Viewport Size Code:
Login | Create New Account
picture

  MENU

About | Classical Genetics | Timelines | What's New | What's Hot

About | Classical Genetics | Timelines | What's New | What's Hot

icon

Bibliography Options Menu

icon
QUERY RUN:
HITS:
PAGE OPTIONS:
Hide Abstracts   |   Hide Additional Links
NOTE:
Long bibliographies are displayed in blocks of 100 citations at a time. At the end of each block there is an option to load the next block.

Bibliography on: Horizontal Gene Transfer

The Electronic Scholarly Publishing Project: Providing world-wide, free access to classic scientific papers and other scholarly materials, since 1993.

More About:  ESP | OUR CONTENT | THIS WEBSITE | WHAT'S NEW | WHAT'S HOT

ESP: PubMed Auto Bibliography 07 Sep 2025 at 01:30 Created: 

Horizontal Gene Transfer

The pathology-inducing genes of O157:H7 appear to have been acquired, likely via prophage, by a nonpathogenic E. coli ancestor, perhaps 20,000 years ago. That is, horizontal gene transfer (HGT) can lead to the profound phenotypic change from benign commensal to lethal pathogen. "Horizontal" in this context refers to the lateral or "sideways" movement of genes between microbes via mechanisms not directly associated with reproduction. HGT among prokaryotes can occur between members of the same "species" as well as between microbes separated by vast taxonomic distances. As such, much prokaryotic genetic diversity is both created and sustained by high levels of HGT. Although HGT can occur for genes in the core-genome component of a pan-genome, it occurs much more frequently among genes in the optional, flex-genome component. In some cases, HGT has become so common that it is possible to think of some "floating" genes more as attributes of the environment in which they are useful rather than as attributes of any individual bacterium or strain or "species" that happens to carry them. For example, bacterial plasmids that occur in hospitals are capable of conferring pathogenicity on any bacterium that successfully takes them up. This kind of genetic exchange can occur between widely unrelated taxa.

Created with PubMed® Query: ( "horizontal gene transfer" OR "lateral gene transfer") NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

-->

RevDate: 2025-09-06

Zhang B, Hu X, Guo Z, et al (2025)

In-situ remediation efficiency and mechanism of tylosin contaminated soil with biochar immobilized degrading enzyme.

Journal of hazardous materials, 497:139483 pii:S0304-3894(25)02399-4 [Epub ahead of print].

Residues of veterinary antibiotics such as tylosin in soils can induce selective pressure on indigenous soil microbes and increase the dissemination risk of antibiotic resistance genes (ARGs) by horizontal gene transfer (HGT), which poses a serious threat to both soil and public health. While conventional bioremediation methods face challenges in efficiency and stability, enzyme-based approaches offer promising alternatives. This study developed a novel biochar-immobilized tylosin-degrading enzyme (BIE) system to simultaneously address tylosin contamination and antibiotic resistance gene (ARG) proliferation in agricultural soils. Using HPLC-MS, qPCR, and 16S rRNA sequencing, we comprehensively evaluated tylosin degradation kinetics, ARG dynamics, and microbial community responses during BIE treatment towards tylosin-contaminated soil. The results revealed the remarkable degradation efficiency of tylosin (99.85 %) by BIE within 7 days. In addition, after 20 days of BIE treatment, the relative abundances of ARGs and mobile gene elements (MGEs) significantly decreased by 11.63-100 % depending on the specific gene which favored the recovery of soil bacterial community diversity. Mechanistic studies revealed that biochar synergistically enhanced enzyme stability and provided protective microenvironments, enabling efficient lactone bond hydrolysis and tylosin detoxification. These findings establish biochar-immobilized degrading enzyme technology as a sustainable solution for dual challenges of antibiotic persistence and resistance spread in contaminated soils. Future research should focus on field validation, large-scale application protocols, and long-term ecological impacts to facilitate practical implementation of this innovative approach.

RevDate: 2025-09-06

Zhang J, Li W, Zhang X, et al (2025)

Higher chlorine dosage does not consistently enhance antibiotic resistance mitigation in the Cl2-UV process.

Water research, 287(Pt B):124534 pii:S0043-1354(25)01438-1 [Epub ahead of print].

Health problems arising from antibiotic resistance are a global concern. The Cl2-UV disinfection process has shown potential for controlling antibiotic resistance in water; however, the influence of disinfectant dosage on its effectiveness remains insufficiently understood. Can antibiotic resistance be controlled by simply increasing the disinfectant dosage? This study demonstrated that higher disinfectant levels improved antibiotic resistance gene (ARG) removal, with certain ARGs reaching 1.82 log removal under conventional conditions. Nevertheless, higher disinfectant dosages also led to an increase in the relative abundance of multidrug resistance genes (MRGs), aminoglycoside resistance genes (AmRGs), and fosmidomycin resistance genes (FRGs). Correlation analysis of ARGs with mobile genetic elements (MGEs) and ARG-host bacteria indicated that this enrichment was primarily driven by enhanced horizontal gene transfer (HGT). Notably, increases in UV fluence and chlorine dose had distinct impacts on the total relative abundance of ARGs: higher UV fluence reduced total relative abundance, whereas higher chlorine dose increased it. These contrasting trends are likely linked to differences in the dominant HGT pathways under each condition. Greater UV fluence tended to promote conjugative transfer among surviving bacteria, while higher chlorine dosages more effectively facilitated natural transformation. Considering both the absolute and relative abundances of ARGs, along with calculated health-risk indices for each treatment condition, the findings indicated that increasing UV fluence is more effective for controlling ARGs in water. These results provide valuable insights for optimizing the Cl2-UV disinfection process to better manage antibiotic resistance in aquatic environments.

RevDate: 2025-09-05
CmpDate: 2025-09-05

Chang ACG, Amaral MWW, Greenwood M, et al (2025)

Evolutionary dynamics in plastomes and mitogenomes of diatoms.

PloS one, 20(9):e0331749.

Diatoms are pivotal in global oxygen, carbon dioxide, and silica cycling, contributing significantly to photosynthesis and serving as fundamental components in aquatic ecosystems. Recent advancements in genomic sequencing have shed light on their evolutionary dynamics, revealing evolutionary complex genomes influenced by symbiotic relationships and horizontal gene transfer events. By analyzing publicly available sequences for 120 plastomes and 70 mitogenomes, this paper aims to elucidate the evolutionary dynamics of diatoms across diverse lineages. Gene losses and pseudogenes were more frequently observed in plastomes compared with mitogenomes. Overall, gene losses were particularly abundant in the plastomes of Astrosyne radiata, Toxarium undulatum, and Proboscia sp. Frequently lost and pseudogenized genes were acpP, ilv, serC, tsf, tyrC, ycf42 and bas1. In mitogenomes, mttB, secY and tatA genes were lost repeatedly across several diatom taxa. Analysis of nucleotide substitution rates indicated that, in general, mitogenomes were evolving at a more rapid rate compared to plastomes. This is contrary to what was observed in synteny analyses, where plastomes exhibited more structural rearrangements than mitogenomes, with the exception of the genus Coscinodiscus and one group of species within Thalassiosira.

RevDate: 2025-09-05

Liu Y, X Wang (2025)

Post-translational Modifications of the Nucleoid Protein H-NS: Sites, Mechanisms, and Regulatory Cues.

FEMS microbiology reviews pii:8248507 [Epub ahead of print].

Histone-like nucleoid structuring protein H-NS plays a pivotal role in orchestrating bacterial chromatin and regulating horizontal gene transfer (HGT) elements. In response to environmental signals, H-NS undergoes dynamic post-translational modifications (PTMs) that resemble the epigenetic codes of eukaryotic histones. This review explores how environmental cues regulate PTMs at specific sites within distinct domains of H-NS, thereby modulating its oligomerization and DNA-binding capabilities to reprogram bacterial responses. Notably, HGT elements commonly encode counter-silencing factors, including PTM-modifying enzymes, that counteract H-NS repression. We propose that combinatorial PTM patterns on H-NS form the bacterial histone-like epigenetic code, regulating the expression of HGT elements. Collectively, these interactions establish a sophisticated network of silencing and counter-silencing mechanisms that drive bacterial genome evolution.

RevDate: 2025-09-05

Vandierendonck J, Valcek A, Nguyen VS, et al (2025)

Isolation and characterization of bacteriophages from clinical enterohemorrhagic Escherichia coli strains.

Microbiology spectrum [Epub ahead of print].

Temperate bacteriophages play a pivotal role in the biology of their bacterial host. Of particular interest are bacteriophages infecting enterohemorrhagic E. coli (EHEC) due to their significant contribution to the pathogenicity of its host, most notably by encoding the key virulence factor of this pathogen, the Shiga toxin. To better understand the role of EHEC phages on the functionality of its host, we isolated eight temperate phages from clinical EHEC isolates and characterized their genomic composition, morphology, and receptor targeting. Morphological analysis identified one long-tailed siphophage, targeting the OmpC receptor for host recognition, whereas the other seven phages are short-tailed podophages and target the essential BamA protein. Genomic characterization revealed significant variations between the long- and short-tailed phages. Five of the eight isolated phages encode the potent Shiga toxin. Comparative analysis displays the typical lambdoid mosaicism, indicative of horizontal gene transfer driving evolution. These findings provide insights into the genetic and morphologic diversity and receptor specificity of EHEC phages, highlighting their role in the evolution and pathogenicity of clinical EHEC strains.IMPORTANCECharacterizing bacteriophages from clinical EHEC isolates is crucial in understanding the mechanisms underlying bacterial evolution and virulence. Despite the clinical relevance of EHEC bacteriophages, they remain underexplored, and particularly phage receptors are often not characterized. Studying temperate EHEC phages is essential in the development of strategies to address the global burden of these foodborne infections. Notably, identifying the phage receptors is critical in unraveling the specific interaction between phage and host. Knowledge of the phage receptors can provide insights into the mechanisms of phage infection, host range, and bacterial resistance and is fundamental in the design of targeted therapies like new antimicrobials, phage therapy, or prevention of those infections.

RevDate: 2025-09-05

Stepanauskas R, Brown JM, Arasti S, et al (2025)

Net rate of lateral gene transfer in marine prokaryoplankton.

The ISME journal pii:8248340 [Epub ahead of print].

Lateral gene transfer is a major evolutionary process in Bacteria and Archaea. Despite its importance, lateral gene transfer quantification in nature using traditional phylogenetic methods has been hampered by the rarity of most genes within the enormous microbial pangenomes. Here, we estimated lateral gene transfer rates within the epipelagic tropical and subtropical ocean using a global, randomized collection of single amplified genomes and a non-phylogenetic computational approach. By comparing the fraction of shared genes between pairs of genomes against a lateral gene transfer-free model, we show that an average cell line laterally acquires and retains ~13% of its genes every 1 million years. This translates to a net lateral gene transfer rate of ~250 genes L-1 seawater day-1 and involves both "flexible" and "core" genes. Our study indicates that whereas most genes are exchanged among closely related cells, the range of lateral gene transfer exceeds the contemporary definition of bacterial species, thus providing prokaryoplankton with extensive genetic resources for lateral gene transfer-based adaptation to environmental stressors. This offers an important starting point for the quantitative analysis of lateral gene transfer in natural settings and its incorporation into evolutionary and ecosystem studies and modeling.

RevDate: 2025-09-04

Chu WC, Wu YX, FF Liu (2025)

Bio-based microplastics as vectors of resistance genes under combined pressure of antibiotics and heavy metals in marine environment.

Journal of hazardous materials, 497:139698 pii:S0304-3894(25)02617-2 [Epub ahead of print].

In this study, we investigated the characteristics of biofilm formation on petroleum-based polyethylene (PE) and bio-based polylactic acid (PLA) microplastics, the structure of bacterial communities, and the enrichment and transfer of related resistance genes in marine environments. We examined these factors under varying concentrations of the heavy metal zinc (Zn) and the sulfadiazine (SDZ), both individually and in combination, and analyzed the underlying mechanisms and interrelationships. The results indicated that PE surface was more conducive to bacterial colonization and biofilm stabilization. Conversely, the prolonged combined exposure to SDZ and Zn promoted the growth of PLA biofilm. Bacterial communities within the biofilms responded to external stresses through oxidative stress responses, alterations in extracellular polymeric substances, shifts in the relative abundance of specific microbial taxa, and adjustments in metabolic pathways. These adaptations positively influenced the enrichment and transfer of resistance genes. Under experimental conditions, PLA microplastics were more likely than PE to serve as carriers of resistance genes in marine environments. Zn promoted the spread of resistance genes by enhancing horizontal gene transfer (HGT) in the short term, and in the later stages, shaped microbial community composition and co-selected with SDZ, thereby influencing the distribution and dissemination of resistance genes.

RevDate: 2025-09-04

Li J, Zuo J, Xu H, et al (2025)

Sub-inhibitory gentamicin promotes extracellular vesicles biogenesis and blaNDM dissemination in carbapenem-resistant Escherichia coli via mrdA/mrdB pathway.

Veterinary microbiology, 310:110704 pii:S0378-1135(25)00339-6 [Epub ahead of print].

The increasing prevalence of carbapenem-resistant Escherichia coli (CRE) in swine production poses a significant public health threat, largely driven by the misuse of antibiotics. Recent studies highlight extracellular vesicles (EVs) as emerging mediators of horizontal gene transfer and antibiotic resistance dissemination. In this study, we investigated the regulatory effects of sub-inhibitory concentrations of gentamicin (GEN), a commonly used antibiotic in pig farms, on EVs production and blaNDM gene transfer in CRE isolates. EVs purified from porcine CRE strains exhibited typical spherical morphology with average diameters around 100 nm and particle concentrations exceeding 2.0 × 10 [11] particles/mL. Treatment with 1/64 minimum inhibitory concentration (MIC) GEN significantly increased EV secretion and enhanced the protective effect of EVs against meropenem in both intra-species (E. coli ATCC 25922) and inter-species recipient strains (S. Typhimurium ATCC 14028, P. aeruginosa ATCC 15692, K. pneumoniae CMCC 46117, L. monocytogenes ATCC 19115, and O. burkholderi ATCC 25416), in a dose- and time-dependent manner. Moreover, GEN-induced EVs facilitated blaNDM-5 (New Delhi metallo-β-lactamase-5) transfer preferentially to E. coli strains. Transcriptomic analysis revealed that GEN treatment led to differential expression of multiple genes, among which mrdA and mrdB were identified as key regulators of EVs biogenesis. Targeted deletion of mrdA or mrdB markedly reduced EVs production and blaNDM transfer frequency. These findings suggest that the mrdA/mrdB pathway plays a crucial role in GEN-mediated EVs formation and resistance gene dissemination, providing novel insights into the molecular mechanisms by which sub-inhibitory antibiotic exposure promotes antimicrobial resistance propagation. Our work may inform future strategies for controlling resistance dissemination in livestock production.

RevDate: 2025-09-04

Nucci A, Le Bris J, Diaz-Diaz S, et al (2025)

Phenotypic heterogeneity of capsule production across opportunistic pathogens.

mBio [Epub ahead of print].

Phenotypic heterogeneity allows bacteria to adapt fast to changing environments. Extracellular capsules are well-known virulence factors, but also increase the cell adaptability and prevalence under hostile conditions. To limit their cost, some species regulate capsule production by genetic phase variation. Here, we demonstrated that phenotypic heterogeneity is a major mechanism controlling capsule production in Klebsiella and Acinetobacter species. We designed a method to agnostically measure heterogeneity and show that 71% of Klebsiella pneumoniae strains can be heterogeneous. This is mostly associated with K. pneumoniae strains that do not encode rmp, a genetic determinant of hypervirulence. Capsule serotype exchanges across several genetic backgrounds revealed that heterogeneity depends on specific genome-capsule locus interactions. Importantly, we showed that heterogeneity provides a fitness advantage especially in conditions where the capsule is costly, as estimated by comparing non-heterogeneous and heterogeneous strains during competition with their non-capsulated variants. Finally, heterogeneity impacts phage adsorption patterns, and could thus alter the rate of horizontal gene transfer events. This unsuspected heterogeneity may help understand the transition from commensalism to pathogenesis and can have important implications in virulence, environmental survival and evolution of some ESKAPE pathogens.IMPORTANCEThe polysaccharidic capsule is present in ~50% of species across the bacterial phylogeny, including all ESKAPE microorganisms, the six most significant multidrug-resistant (MDR) nosocomial pathogens. It is also an important virulence factor and a major target for both phage therapy and the development of vaccines. Here, we reveal that in two major genera of ESKAPE pathogens, Klebsiella spp. and Acinetobacter spp., capsule production within clonal populations is heterogeneous, leading to mixed populations of hyper-, hypo-, and intermediate-capsulated cells. Such heterogeneity responds to different environmental cues, including changes in nutrient availability and spatial structure. We show that this plasticity, known to enable faster, more efficient adaptation to environmental changes, limits capsule costs and could explain Klebsiella and Acinetobacter resilience. Finally, capsule heterogeneity can play a major role in bacterial evolution, as a driver of horizontal gene transfer, and in treatment failure. Thus, it should be taken into account in the design of prophylactic strategies and antimicrobial therapy.

RevDate: 2025-09-04

Bucknell A, Wilson HM, Gonçalves Dos Santos KC, et al (2025)

Sanctuary: a Starship transposon facilitating the movement of the virulence factor ToxA in fungal wheat pathogens.

mBio [Epub ahead of print].

There is increasing evidence that mobile genetic elements can drive the emergence of pathogenic fungal species by moving virulence genes horizontally. The 14 kbp ToxhAT transposon was shown to move the necrotrophic effector, ToxA, horizontally between wheat pathogens, namely Parastagonospora nodorum, Pyrenophora tritici-repentis, and Bipolaris sorokiniana. All three species utilize the ToxA protein to infect wheat. Previous work found ToxhAT in distinct chromosomal positions in two B. sorokiniana isolates, indicating that the transposon remains active in this species. Here, we confirm the movement of ToxhAT using long-read sequencing of eight new and one previously published B. sorokiniana isolates. One event of independent transposition of ToxhAT was observed, and target site duplications of "TA" were identified, confirming that this is an active transposon in this species that likely falls into the Tc1/Mariner transposon family. We propose renaming this non-autonomous transposon to ToxTA. Whole genome analysis revealed that ToxTA is a passenger embedded in a much larger, conserved 170-196 kbp mobile genetic element. This element, termed Sanctuary, belongs to the newly described Starship transposon superfamily. This classification is based on the presence of direct repeats, empty insertion sites, a putative tyrosine recombinase gene, and other features of Starship transposons. We also show that ToxTA has been independently acquired by two different Starships, Sanctuary and Horizon, which share little to no sequence identity, outside of ToxTA. This classification makes Horizon and Sanctuary part of a growing number of Starships involved in the horizontal gene transfer of adaptive genetic material between fungal species.IMPORTANCEThe work presented here expands our understanding of a novel group of mobile genetic elements called Starships that facilitate the horizontal exchange of numerous genes between fungal pathogens. Our analysis shows that Sanctuary and ToxTA are both active transposons within the Bipolaris sorokiniana genome. We also show that the smaller ToxTA transposon has been independently acquired by two different Starships, namely Sanctuary in B. sorokiniana and Horizon in Pyrenophora tritici-repentis and Parastagonospora nodorum. Outside of ToxTA, these two Starships share no sequence identity. The acquisition of ToxTA by two different mobile elements in three different fungal wheat pathogens demonstrates how horizontal transposon transfer is driving the evolution of virulence in these important wheat pathogens.

RevDate: 2025-09-04
CmpDate: 2025-09-04

Wang C, Qin JX, Li M, et al (2025)

[Genomic characteristics and mechanisms of horizontal plasmid transfer in Klebsiella pneumoniae producing NDM-1 and IMP-4 carbapenemases].

Zhonghua yi xue za zhi, 105(34):3013-3016.

A retrospective analysis was conducted on a clinically isolated Klebsiella pneumoniae strain KP1050 that produces both New Delhi Metallo-β-lactamase (NDM)-1 and Imipenem-hydrolyzing β-lactamase (IMP)-4 carbapenemases. The minimum inhibitory concentrations of various antimicrobial agents were determined using the microbroth dilution method. Whole-genome sequencing was performed to identify the resistance genes and resistance plasmids carried by the strain. Conjugation assays and gene knockout techniques were employed to clarify the mechanisms of horizontal transfer of resistance plasmids. Klebsiella pneumoniae KP1050 was resistant to multiple antimicrobial agents, including carbapenems, and only susceptible to amikacin, tigecycline, and polymyxin. The strain belonged to ST1245, carrying the blaNDM-1 and blaIMP-4 carbapenemase resistance genes on the 59 730 bp IncN-type and 289 270 bp IncHI5-type plasmids, respectively. Both IncN and IncHI5-type plasmids harbored complete gene clusters encoding the type Ⅳ secretion system and could be conjugated to recipient bacteria; however, the conjugation efficiency of the IncN-type NDM-1 plasmid (1×10[-3]) was higher than that of the IncHI5-type IMP-4 plasmid (5×10[-6]). Knockout of key genes in the plasmid type Ⅳ secretion system revealed that the IncHI5-type IMP-4 plasmid was not an independently conjugative plasmid but could undergo horizontal transmission through conjugation with the assistance of the IncN-type NDM-1 plasmid. Interactions between plasmids can promote the spread of carbapenemase resistance genes.

RevDate: 2025-09-02

Zhu L, Chen K, Xu L, et al (2025)

Genomic Investigation of a Bacillus subtilis Strain Sourced from Commercially Available Milk Powder in China Reveals Potential Risk Factors.

Infection and drug resistance, 18:4311-4328.

BACKGROUND: Milk powder is a key food source, especially for infants and vulnerable groups. However, Bacillus contamination during production, storage, or handling can cause spoilage, quality issues, or health risks. This study identified and isolated Bacillus subtilis from commercially available Chinese milk powder.

METHODS: A pure colony of Bacillus subtilis was isolated from an LB agar plate supplemented with milk powder and identified using mass spectrometry. The genome of this strain was sequenced using third-generation sequencing technology. Following assembly, the genome was functionally annotated and subjected to comprehensive bioinformatic analysis.

RESULTS: Genomic analysis classified the strain as Bacillus subtilis via MALDI-TOF and ANI (98.82% with B. subtilis AMR1). Its genome features a 4.26 Mbp chromosome and 97.6 kbp plasmid encoding 4,539 genes, including virulence factors (209 genes), antibiotic resistance genes (19 genes), and carbohydrate-active enzymes (253 genes). Key virulence mechanisms include immune modulation, stress adaptation, toxin production, and biofilm formation. Antibiotic resistance involves efflux pumps (eg, qacJ, bmr), enzymatic inactivation (eg, FosBx1, aadK), and target modification (eg, vanG cluster, tet(45)). Phylogenetically (LIN78), the strain clusters with foodborne B. subtilis isolates (eg, from Korean gochujang and soybean), diverging from B. cereus and environmental Bacillus clades. Comparative genomics revealed 53 LIN78-specific genes, encompassing defense mechanisms and mobile elements, and synteny in all homologs except B. subtilis ATCC 11774. Genomic islands, CRISPR arrays, and recombination-associated repeats indicate adaptive evolution.

CONCLUSION: This study characterizes Bacillus subtilis LIN78, a genomically plastic strain isolated from Chinese milk powder. It exhibits adaptation to food environments via horizontal gene transfer, stress tolerance, and spoilage traits, while carrying antimicrobial resistance risks and potential biotechnological applications. The findings necessitate genomic monitoring to manage food safety, resistance spread, and leverage its dual role as both a spoilage organism and source of bioactive compounds..

RevDate: 2025-09-04
CmpDate: 2025-09-04

Fang Z, Li Y, Huang J, et al (2025)

Experimental insights into genome reconstruction driven by horizontal transfer of supernumerary chromosomes in Magnaporthe oryzae.

The New phytologist, 248(1):140-156.

Many pathogenic fungi display 'two-speed genome', with the fast-evolving genomic compartments enriched with repetitive sequences, particularly the transposons, which have been shown to drive the variation of pathogenicity-associated genes. Supernumerary chromosomes (SCs) are known to facilitate genomic variation in fungal pathogens, but their specific role in such processes remains understudied. In this study, we assessed the transferability of SCs between asexual Magnaporthe oryzae strains during co-culture and co-infection, and investigated their role in genome reconstruction through experimental evolution assays. We found that SCs could be horizontally transferred between M. oryzae strains and revealed frequent structural variations facilitated by SCs, including deletions, duplications, translocations, and SC-core chromosome recombinations during and after horizontal transfer. Remarkably, all observed intra- and inter-chromosome rearrangements were confined to core chromosome ends and SCs, indicating a robust role of SCs in facilitating genetic exchange within fast-evolving genomic compartments. Additionally, SC carrying the avirulence gene AvrPik[E] modulates M. oryzae virulence against Pikh rice through horizontal transfer, loss of whole SC, and segmental deletions. Our findings establish SCs as critical players in shaping the diversity and dynamics of the pathogenic fungal genomes, highlighting them as a cradle for the variation of pathogenicity-associated genes.

RevDate: 2025-09-04
CmpDate: 2025-09-04

Rana MS, Kim S, Ko SY, et al (2025)

Co-carriage of blaNDM-1 and blaVIM-2 in different plasmids of Acinetobacter junii isolate and the transfer of blaNDM-1-carrying plasmids to Gram-negative bacteria.

Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi, 58(5):613-616.

Carbapenem-resistant Acinetobacter junii isolate co-carried blaVIM-2 and blaNDM-1 in different plasmids. blaNDM-1- and blaVIM-2-carrying plasmids were characterized using the whole genome sequencing. The expression of blaNDM-1 was higher than that of blaVIM-2. blaNDM-1-carrying plasmid was conjugally transferred to various Gram-negative bacterial species. The transferability of blaNDM-1-carrying plasmid raises concerns about the potential spread of carbapenem resistance across diverse bacterial populations.

RevDate: 2025-09-03
CmpDate: 2025-09-03

Muller H, Savisaar R, Peccoud J, et al (2025)

Phylogenetic relatedness rather than aquatic habitat fosters horizontal transfer of transposable elements in animals.

Genome research, 35(9):2011-2022.

Horizontal transfer of transposable elements (HTT) is an important driver of genome evolution, yet the factors conditioning this phenomenon remain poorly characterized. Here, we screen 247 animal genomes from four phyla (annelids, arthropods, mollusks, chordates), spanning 19 independent transitions between aquatic and terrestrial lifestyles, to evaluate the suspected positive effects of aquatic habitat and of phylogenetic relatedness on HTT. Among the 6043 independent HTT events recovered, the vast majority (>85%) involve DNA transposons, of which Mariner-like and hAT-like elements have the highest rates of horizontal transfer and of intragenomic amplification. Using a novel approach that circumvents putative biases linked to phylogenetic inertia and taxon sampling, we find that HTT rates positively correlate with similarity in habitat type but are not significantly higher in aquatic than in terrestrial animals. However, modeling the number of HTT events as a function of divergence time in a Bayesian framework reveals a clear positive effect of phylogenetic relatedness on HTT rates in most of the animal species studied (162 out of 247). The effect is very pronounced: A typical species is expected to show 10 times more transfers with a species it diverged from 250 million years (My) ago than with a species it diverged from 650 My ago. Overall, our study underscores the pervasiveness of HTT throughout animals and the impact of evolutionary relatedness on its dynamics.

RevDate: 2025-09-02

Tanu R, Chaudhary AA, Prakash G, et al (2025)

Exploring the potential of photodynamic therapy in overcoming multidrug resistance: mechanisms, synergies, and clinical advancements in infectious diseases.

Frontiers in cellular and infection microbiology, 15:1624036.

Multidrug resistance (MDR) in bacterial and fungal pathogens poses a growing global health crisis, rendering many conventional antimicrobial therapies ineffective. The rise of MDR strains complicates treatment, prolongs illness, increases healthcare costs, and contributes to higher mortality rates. Mechanisms driving MDR include enzymatic drug inactivation, target modification, efflux pump activity, decreased permeability, and biofilm formation-often fueled by horizontal gene transfer and selective pressure from antimicrobial overuse. In response to the urgent need for novel therapeutic strategies, photodynamic therapy (PDT) has emerged as a promising, non-traditional approach. PDT utilizes a photosensitizing agent, light of a specific wavelength, and oxygen to generate reactive oxygen species (ROS) that inflict oxidative damage on microbial or cancer cells. This mechanism circumvents conventional resistance pathways, offering targeted, minimally invasive, and effective treatment for infections and malignancies. PDT is particularly adept at penetrating biofilms and resistant microbial populations, thus broadening its clinical applicability. In addition to direct microbial eradication, PDT may stimulate immune responses and demonstrates a favorable safety profile compared to traditional antibiotics or chemotherapy. Furthermore, advances in Antimicrobial Blue Light (aBL) and next-generation photosensitizers enhance PDT's effectiveness while minimizing resistance development. This review explores the biological mechanisms underlying MDR, the principles and evolution of PDT, and its synergistic potential in managing infectious diseases. By addressing critical gaps in antimicrobial therapy, PDT stands out as a transformative modality in the ongoing battle against drug-resistant pathogens.

RevDate: 2025-09-02

Khan MSI, Wu J, Ji S, et al (2025)

Expanding structural insights into DNA packaging apparatus and endolysin LysSA05 function of Epsilon15 bacteriophage.

Frontiers in cellular and infection microbiology, 15:1643576.

The rising prevalence of multidrug-resistant (MDR) foodborne pathogens, particularly Salmonella spp., necessitates alternative antimicrobial solutions. Phage therapy offers a promising solution against MDR Gram-negative infections; however, its clinical application is constrained by the presence of endotoxins, residual cellular debris, the risk of horizontal gene transfer by temperate phages, and an incomplete understanding of how phage structural integrity influences infectivity and enzyme function. In this study, we present a structural and functional analysis of temperate bacteriophage Epsilon15 (ϵ15), focusing on its DNA packaging and injection machinery, along with characterization of the dual-acting endolysin LysSA05. Iodixanol-purified virions suspended in phosphate-buffered saline (PBS), under conditions optimized to preserve virion stability, were analyzed using graphene oxide (GO)-supported cryo-electron microscopy. This approach resolved the full asymmetric architecture of ϵ15, revealing a detailed internal nucleic acid organization with at least eight concentric layers radially and approximately 28 axially compacted layers within the capsid. The DNA packaging machinery, comprising the core, portal, and hub, was resolved at high resolution, including a 42 nm-long and 18 nm-wide injection channel anchored by a dodecameric portal complex visualized at ~7 Å resolution. Concurrently, we characterized LysSA05, a dual-acting endolysin harboring a glycoside hydrolase 19 (GH19) catalytic domain accommodating peptidoglycan (PG) residues N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) through structural docking, indicating plausible binding interactions that promote hydrolysis support vector machine (SVM), random forest (RF), discriminant analysis (DA), artificial neural network (ANN) and physicochemical scanning identified an amphipathic helix (residues 59-112) with predicted antimicrobial peptide (AMP)-like properties. Biochemical validation confirmed that LysSA05 destabilizes lipopolysaccharides (LPS) and permeabilizes the outer membrane of Gram-negative bacteria independently of permeabilizers, with enhanced efficacy observed upon co-treatment with Ethylenediaminetetraacetic acid (EDTA) or citric acid. In summary, our findings elucidate key structural features of ϵ15 relevant to infection and genome delivery, while positioning LysSA05 as a promising enzybiotic candidate against MDR Gram-negative pathogens.

RevDate: 2025-09-02

Charbonnier M, Probst-Lotze S, Racine H, et al (2025)

A Zur-dependent regulatory RNA involved in maintaining zinc homeostasis in Staphylococcus aureus.

bioRxiv : the preprint server for biology pii:2025.08.23.671911.

Small regulatory RNAs (sRNAs) are key drivers of bacterial adaptation to environmental fluctuations, including iron and manganese restriction imposed by the host. This study explored the repertoire of sRNAs produced by the human pathogen Staphylococus aureus in response to metal limitation. Two sRNAs, S1077 and ZinS (RsaX20), regulated by zinc (Zn) availability, were identified. Further investigations revealed that, similar to the cnt operon from which it derives, S1077 synthesis is controlled by the transcription factors Zur and Fur. In contrast, zinS transcription is solely repressed by Zur. Amongst the ZinS targets are several Zn-dependent enzymes, such as the alcohol dehydrogenase Adh, whose synthesis is negatively regulated by ZinS. Loss of ZinS does not alter staphylococcal metal accumulation, suggesting a role in a Zn-sparing response. Remarkably, zinS also encodes a small peptide, ZinP. Genomic analysis suggests that the regulatory portion of ZinS emerged from the 3' untranslated region of zinP in S. aureus and closely related species after horizontal gene transfer from phylogenetically distant organisms. All our findings demonstrate that sRNAs also facilitate bacterial adaptation to Zn limitation, and that genetic exchange and subsequent neofunctionalization have enabled S. aureus to adapt to metal-restricted environments.

RevDate: 2025-09-02

Forterre P (2025)

Extensive lateral gene transfer between proto-eukaryotes and Heimdallarchaeia suggests their close association during eukaryogenesis.

mLife, 4(4):345-362 pii:MLF270030.

It has been proposed by Ettema and colleagues, in the two-domain framework for the tree of life, that Eukarya emerged from Heimdallarchaeia, as sister group to Hodarchaeales. Looking at the individual trees of the protein markers used by these authors, I notice that Eukarya are only sister to Hodarchaeales or other Heimdallarchaeia in a minority of trees, whereas they are located far apart from these Asgard archaea in most other trees. Examination of single trees also reveals massive gene transfers from Crenarchaeota and/or Korachaeota to hyperthermophilic Njordarchaeales, explaining why their belonging to Asgard archaea is sometimes difficult to recover. Finally, I discuss several points raised by Ettema and colleagues, such as the phylogeny of Asgard archaea and the hyperthermophilic nature of their last common ancestor. The patchy localization of Eukarya in individual trees relative to Hodarchaeales and other Heimdallarchaeia, as well as the patchy distribution of eukaryotic signature proteins among Asgard archaea, is best explained by suggesting that multiple gene transfers take place between proto-eukaryotes and Asgard archaea in both directions. This suggests that the co-evolution of proto-eukaryotes and Asgard archaea has played a major role in eukaryogenesis but also in shaping the physiology and diversification of Asgard archaea.

RevDate: 2025-09-02

Wang X, Fan F, Dong S, et al (2025)

Emergence of carbapenem-resistant Serratia marcescens co-harboring blaNDM-1, blaKPC-2, and blaSRT-2 in bloodstream infection.

Microbiology spectrum [Epub ahead of print].

Serratia marcescens is an emerging opportunistic pathogen with high genetic diversity. The emergence and prevalence of carbapenem-resistant S. marcescens poses a major health threat due to its intrinsic resistance to multiple antibiotics, which severely restricts the selection and treatment of antibiotics for S. marcescens infection. This study presents the first documented case in China of a bloodstream infection caused by Staphylococcus epidermidis and S. marcescens strain (designated S96) co-producing blaNDM-1, blaKPC-2, and blaSRT-2. Strain S96 exhibited resistance to nearly all categories of β-lactam antimicrobials, β-lactam/inhibitor combinations, aminoglycosides, quinolones, and other clinical antibacterial agents, with the exception of tigecycline. Our main objective was to characterize the genetic mechanisms underlying its carbapenem resistance and plasmid transfer potential. Whole-genome sequencing revealed blaKPC-2 on a 44,047 bp "IncX6-like" plasmid and blaNDM-1 on a 100,081 bp IncFII(Yp)-type plasmid, alongside chromosomal blaSRT-2 and aac(6')-Ic. "IncX6-like" and IncFII(Yp)-type plasmids are widely distributed among carbapenem-resistant Enterobacteriaceae strains globally. Conjugation experiments demonstrated that the blaNDM-1-carrying plasmid could be successfully transferred to recipient Escherichia coli 600, with no significant fitness cost observed (P > 0.05). The experimental results demonstrate that carbapenem-resistant genes can disseminate among Enterobacteriaceae via plasmid-mediated horizontal transfer between bacterial cells. Comparative genomic analysis revealed plasmid structural homology with global counterparts, demonstrating IS-mediated recombination and horizontal gene transfer. The low adaptive cost of plasmid carriage and multidrug resistance phenotype pose significant challenges for clinical management. This study highlights the need for enhanced clinical surveillance and antibiotic stewardship to curb the spread of such multidrug-resistant pathogens.IMPORTANCECarbapenem resistance in Serratia marcescens is primarily mediated by Klebsiella pneumoniae carbapenemase (KPC), with New Delhi metallo-β-lactamase (NDM) being a relatively uncommon alternative resistance mechanism. KPC-2 and NDM-1 coexisting in S. marcescens is extremely rare clinically. This study reports the first clinical isolate of S. marcescens in China co-harboring blaNDM-1, blaKPC-2, and blaSRT-2. The isolate exhibits multidrug resistance to nearly all β-lactam antibiotics and β-lactam/inhibitor combinations, with low adaptive costs and high dissemination potential. The potential spread of resistance genes through mobile genetic elements poses a serious public health risk. The study underscores the need for enhanced surveillance, rational antibiotic use, and novel strategies to combat resistance. It also provides insights into the evolutionary mechanisms of bacterial resistance, emphasizing the urgent need for interventions to address the growing threat of antimicrobial resistance.

RevDate: 2025-09-01

RoyChowdhury D, Manna A, Mandal S, et al (2025)

Colistin resistance in the era of antimicrobial resistance: challenges and strategic countermeasures.

Folia microbiologica [Epub ahead of print].

Colistin resistance represents a mounting global health concern, particularly alarming in the face of multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacterial infections. As a polymyxin-class antibiotic, colistin has long served as a critical last-line defence against severe Gram-negative infections caused by pathogens such as Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae. However, its increasing and, at times, indiscriminate use has driven the emergence of resistant strains, thereby compromising its clinical utility.Mechanistically, colistin resistance arises from diverse genetic adaptations that alter the bacterial outer membrane, diminishing the drug's binding affinity. Prominent among these are modifications to lipopolysaccharides (LPS), including the incorporation of cationic groups that neutralise the membrane's negative charge, effectively impeding colistin interaction. In addition to chromosomal mutations, resistance is often mediated through horizontal gene transfer-most notably via mobile colistin resistance (mcr) genes-which facilitates rapid dissemination among bacterial populations.To counter this growing threat, innovative therapeutic strategies are urgently needed. These include the development of novel antibiotics with distinct mechanisms of action, synergistic combination regimens (e.g., colistin paired with potentiating agents), and the exploration of alternative modalities such as bacteriophage therapy. Gene-editing technologies like CRISPR-Cas9 also offer a promising frontier for targeting resistance determinants directly at the genetic level.Equally important are robust antimicrobial stewardship programmes and comprehensive surveillance systems to monitor resistance trends and guide rational antibiotic use. Ultimately, overcoming colistin resistance demands a multifaceted and integrative approach-one that merges scientific innovation with global public health initiatives.

RevDate: 2025-09-01
CmpDate: 2025-09-01

Wang MG, Liu KD, Jin WJ, et al (2026)

Mechanistic insight into curcumin-induced conjugative plasmid transfer acceleration: Role of intracellular arginine uptake.

Food microbiology, 133:104895.

Curcumin exhibits a broad spectrum of applications spanning multiple domains, including its incorporation in dietary supplements, functional beverages, cosmetic formulations, and nutraceutical products. Nevertheless, its potential influence on the development of antibiotic resistance remains to be fully elucidated. Therefore, this study aims to investigate the effects of curcumin on the conjugative transfer of plasmids carrying antibiotic resistance genes (ARGs). Our findings indicate that curcumin significantly enhanced the transfer of RP4 plasmid, as well as clinically relevant plasmids carrying blaNDM, mcr-1 and tet(X4). Further mechanisms analysis revealed that curcumin facilitated plasmid conjugation transfer by increasing bacterial membrane permeability, inducing oxidative stress, and accelerating energy metabolism, while altering the expression levels of key genes involved in horizontal gene transfer (HGT). Notably, curcumin elevated intracellular arginine levels, and exogenous arginine supplementation further promoted plasmid transfer. Arginine uptake genes (artJ, artI and argT) were upregulated following curcumin exposure, and the absence of artJ significantly attenuated curcumin-induced arginine accumulation and plasmid transfer, demonstrating the crucial role of the artJ gene in facilitating curcumin-induced plasmid transfer through its promotion of arginine uptake. These findings provide new insights into an unrecognized risk of curcumin in potentially accelerating the spread of antibiotic resistance, highlight the unintended consequences of curcumin use in the food industry.

RevDate: 2025-09-01

Yang H, Y Wang (2025)

From Fragmentation to Resolution: High-Fidelity Genome Assembly of Zancudomyces culisetae through Comparative Insights from PacBio, Nanopore, and Illumina Sequencing.

G3 (Bethesda, Md.) pii:8244970 [Epub ahead of print].

Zancudomyces culisetae is an obligate symbiotic fungus inhabiting the digestive tracts of aquatic insect larvae, including black flies, midges, and mosquitoes. With a global distribution and high prevalence in disease-transmitting insects, Z. culisetae serves as a model for studying insect gut fungi. A previous draft genome assembly using Illumina short reads provided insights into its genome composition, such as a low GC ratio and evidence of horizontal gene transfer. However, its fragmented nature has limited deeper exploration of the evolutionary mechanisms shaping these gut symbionts. To address this gap, we generated a wealth of genomic resources for Z. culisetae using multiple sequencing platforms, including Illumina, Oxford Nanopore, PacBio-CLR (Complete Long Reads), and PacBio-HiFi (High Fidelity). This also provides an opportunity to compare these popular sequencing methods to suggest the optimal approach for fungal genome assembly. Our results suggest that PacBio-HiFi produced the most complete assembly, yielding a 27.8 Mb genome size with 26 contigs, representing the highest-quality genome of insect gut fungi to date. Additionally, we generated transcriptomic data to support genome annotation, identifying 8,484 protein-coding genes. Despite the improved genome quality, Z. culisetae lacks approximately 20% of Benchmarking Universal Single-Copy Orthologue (BUSCO) commonly found in fungi, reflecting adaptations to its obligate symbiotic lifestyle. This study not only provides valuable genomic resources for insect gut fungal research but also evaluates the strengths and limitations of current genome sequencing and assembly approaches, offering best practices for fungal genome analysis and genetic research.

RevDate: 2025-08-30

Sanati S, Bakhti A, F Mohammadipanah (2025)

Long-term toxic effects of nanoparticles on human microbiota.

Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS), 91:127723 pii:S0946-672X(25)00136-1 [Epub ahead of print].

Synthetic nanomaterials can penetrate various organs, such as the skin, lungs, and gastrointestinal tract, enter systemic circulation, and ultimately reach tissues and human cells. Nanomaterials used in medicine, food, cosmetics, and agricultural processes can accumulate in our intestines and cause dysbiosis. The direct and indirect detrimental impacts of nanomaterials on humans by altering our cells and microbiota are discussed in this paper. These adverse effects of nanomaterials can be slightly reduced by changing their physicochemical characteristics. Some of the gut microbiota can reduce or mitigate the toxicity of nanomaterials through various strategies providing approaches for pro- or postbiotics with detoxifying function. Moreover, nanomaterials influence the rate of horizontal gene transfer. The use of nanomaterials in food, water, and medicines needs to be legitimized based on the duration, dose, type, and level of toxicity. The negative implications of nanomaterials in human cells and their microbiota are surveyed in this paper.

RevDate: 2025-08-29

Khosravi H (2025)

Environmental risks of biofertilizers and their impact on soil microbial diversity: a mini review.

Folia microbiologica [Epub ahead of print].

Chemical fertilizers have substantially increased crop yields but have also contributed to significant environmental challenges, including soil and water contamination and the emergence of human health issues. As a more sustainable alternative, biofertilizers-comprising beneficial microorganisms such as bacteria-have been promoted as eco-friendly solutions. However, their use may pose risks to soil microbial communities and biodiversity under certain conditions. For instance, horizontal gene transfer among bacteria can convert non-pathogenic strains into pathogenic ones. Additionally, the introduction of microbial inoculants may outcompete native microbial species, potentially disrupting soil microbial balance and impairing ecosystem functioning. The long-term effects of biofertilizers on nutrient cycling and soil biodiversity remain insufficiently studied. To mitigate these risks, it is crucial to establish rigorous production standards, prioritize native microbial strains, continuously monitor soil microbial dynamics, and implement comprehensive regulatory frameworks. Therefore, the adoption of biofertilizers in agricultural practices should be approached cautiously and guided by evidence-based regulations.

RevDate: 2025-08-29

Pennings PS (2025)

Explaining the stable coexistence of drug-resistant and -susceptible pathogens: the resistance acquisition purifying selection model.

Epidemics, 52:100848 pii:S1755-4365(25)00036-2 [Epub ahead of print].

Drug resistance is a problem in many pathogens. While overall, levels of resistance have risen in recent decades, there are many examples where after an initial rise, levels of resistance have stabilized. The stable coexistence of resistance and susceptibility has proven hard to explain - in most evolutionary models, either resistance or susceptibility ultimately "wins" and takes over the population. Here, we show that a simple model, mathematically akin to mutation-selection balance theory, can explain several key observations about drug resistance: (1) the stable coexistence of resistant and susceptible strains (2) at levels that depend on population-level drug usage and (3) with resistance often due to many different strains (resistance is present on many different genetic backgrounds). The model is applicable to resistance due to both mutations and horizontal gene transfer (HGT). It predicts that new resistant strains should continuously appear (through mutation or HGT and positive selection within treated hosts) and disappear (due to a fitness cost of resistance). The result is that while resistance is stable, which strains carry resistance is constantly changing. We used data from a longitudinal genomic study on E. coli in Norway to test this prediction for resistance to five different drugs and found that, consistent with the model, most resistant strains indeed disappear quickly after they appear in the dataset. Having a model that explains the dynamics of drug resistance will allow us to plan science-backed interventions to reduce the burden of drug resistance.

RevDate: 2025-08-29

Hong W, Yang Z, Wu G, et al (2025)

Integrating serotyping, MLST, and phenotypic data: decoding the evolutionary drivers of Salmonella pathogenicity and drug resistance.

Applied and environmental microbiology [Epub ahead of print].

Global surveillance of Salmonella enterica reveals dynamic evolutionary forces shaping pathogenicity and antimicrobial resistance (AMR), yet the integration of serotyping, multilocus sequence typing (MLST), and phenotypic landscapes remains unexplored. Here, we dissect 935 Salmonella isolates, collected from both clinical and food chain sources, through integrated genomics and phenomics to resolve population structure, spatiotemporal dynamics, and evolutionary drivers. Salmonella Typhimurium (18.7%) and Salmonella Enteritidis (17.1%) dominate the serotype landscape, while MLST uncovers ST34 (20.7%) as the pivotal sequence type bridging multiple serotypes. Temporal tracking (2018-2022) exposes alarming AMR trajectories: ciprofloxacin resistance doubled (15.3% to 30.4%) by 2020, and tetracycline resistance peaked at 77.3%. The serotype-specific epidemiology reveals that S. Typhimurium declined and then stabilized, S. Enteritidis fluctuated due to vaccination, and S. Derby emerged persistently (+69%). Network analysis reveals two evolutionary clusters: one anchored by S. Typhimurium/S. Enteritidis-ST34/ST11 and another harboring diverse STs associated with S. Derby. Notably, ST34 acts as a genetic backbone for serotype switching. Notably, S. Typhimurium exhibits the highest AMR gene burden (median: 4.2 genes/isolate) and virulence arsenal (spvB: 85.1%; pefA: 75.4%), which correlates with invasive disease. Geographic heterogeneity results in distinct serotype distributions: S. Enteritidis dominates in Xinyu (28.4%), S. Typhimurium prevails in Shangrao (31.5%), and Ganzhou exhibits balanced diversity. Our findings establish that clonal expansion, horizontal gene transfer, and regional ecologies are key factors jointly driving Salmonella evolution. This necessitates genotype-phenotype-integrated surveillance to preempt the emergence and widespread dissemination of resistance and virulence.IMPORTANCESalmonella enterica is a globally significant foodborne pathogen, whose pathogenicity and antimicrobial resistance (AMR) evolution are driven by complex mechanisms. This study provides a comprehensive analysis of 935 Salmonella isolates from clinical and food chain sources, integrating genomic and phenotypic data to elucidate population structure, spatiotemporal dynamics, and key evolutionary drivers. We reveal critical resistance trends, including a concerning doubling of ciprofloxacin resistance by 2020 and sustained high tetracycline resistance. Our comparative analysis of serotypes (e.g., S. Typhimurium and S. Enteritidis) highlights associations between AMR gene burden and virulence factors and identifies ST34 as a pivotal genetic element facilitating serotype switching. These findings underscore the imperative for integrated genotypic-phenotypic surveillance to predict resistance evolution and inform "One Health"-based interventions. By disrupting AMR dissemination across the animal food chain, this research offers novel strategies for global Salmonella control and improved public health outcomes.

RevDate: 2025-08-29

Li XL, Megdadi M, HS Quadri (2025)

Interaction between gut virome and microbiota on inflammatory bowel disease.

World journal of methodology, 15(3):100332.

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is a chronic condition marked by recurring gastrointestinal inflammation. While immune, genetic, and environmental factors are well-studied, the gut virome has received less attention. This editorial highlights the work which investigates the gut virome's role in IBD and its interactions with the bacterial microbiome and host immune system. The gut virome consists of bacteriophages, eukaryotic viruses, and endogenous retroviruses. Among these, Caudovirales bacteriophages are predominant and influence bacterial communities via lysogenic and lytic cycles. Eukaryotic viruses infect host cells directly, while endogenous retroviruses impact gene regulation and immune responses. In IBD, the virome shows distinct alterations, including an increased abundance of Caudovirales phages and reduced Microviridae diversity, suggesting a pro-inflammatory viral environment. Dysbiosis, chronic inflammation, and aberrant immune responses contribute to these changes by disrupting microbial communities and modifying virome composition. Phages affect bacterial dynamics through lysis, lysogeny, and horizontal gene transfer, shaping microbial adaptability and resilience. Understanding these interactions is crucial for identifying novel therapeutic targets and restoring microbial balance in IBD.

RevDate: 2025-08-29

Osunla CA, Akinbobola A, Elshafea A, et al (2025)

Genomic and Bioinformatic Insights Into Enterococcus faecalis From Retail Meats in Nigeria.

International journal of microbiology, 2025:7325430.

Enterococcus faecalis is a commensal and opportunistic pathogen increasingly recognized for its antimicrobial resistance (AMR) and zoonotic potential. This study employs whole-genome sequencing (WGS) to characterize E. faecalis isolates from retail meat samples, focusing on antimicrobial resistance genes (ARGs), virulence determinants, mobile genetic elements, and phylogenomic relationships. Fifty raw meat samples, including chicken (n = 18), beef (n = 17), and turkey (n = 15), were collected from retail markets in Akungba-Akoko, Nigeria. Confirmed isolates underwent antimicrobial susceptibility testing and WGS-based genomic analysis. Ten E. faecalis isolates were recovered, predominantly from chicken. All exhibited resistance to clindamycin, erythromycin, and tetracycline. Dominant AMR genes included aac(6⁣')-aph(2⁣[″]), ant(6)-Ia, lsa(A), erm(B), tet(M), and tet(L). Plasmid replicons rep9c and repUS43 were associated with sequence types ST477 and ST16, respectively. MGEs such as IS3, IS6, IS256, and IS1380 colocalized with resistance and virulence genes. Phylogenomic analysis revealed two major lineages (ST477 and ST16) and indicated geographic clustering across African isolates. The co-occurrence of multidrug resistance, virulence factors, and MGEs in foodborne E. faecalis poses a public health concern due to the risk of horizontal gene transfer and zoonotic spread. These findings support the need for strengthened genomic surveillance and AMR control strategies in food systems, particularly within low- and middle-income countries.

RevDate: 2025-08-29

Torosian N, Covington JK, Cook AM, et al (2025)

Characterization of the thermophilic xylanase Fsa02490Xyn from the hyperthermophile Fervidibacter sacchari belonging to glycoside hydrolase family 10.

FEBS open bio [Epub ahead of print].

Fervidibacter sacchari is an aerobic hyperthermophile belonging to the phylum Armatimonadota that degrades a variety of polysaccharides. Its genome encodes 117 enzymes with one or more annotated glycoside hydrolase (GH) domain, but the roles of these putative GHs in polysaccharide catabolism are poorly defined. Here, we describe one F. sacchari enzyme encoding a GH10 domain, Fsa02490Xyn, that was previously shown to be active on Miscanthus, oat β-glucan, and beech-wood xylan, with optimal activity at 90-100 °C. We show that Fsa02490Xyn is also active on birch-wood xylan and gellan gum. The pH range on beech-wood xylan was 4.5 to 9.5 (pHopt 7.0-8.0). Fsa024940Xyn had a Km of 2.375 mm, Vmax of 1250 μm·min[-1], and kcat/Km of 1.259 × 10[4] s[-1]·m[-1] when using a para-nitrophenyl-𝛽-xylobioside assay. A phylogenetic analysis of GH10 family enzymes revealed a large clade of enzymes from diverse members of the class Fervidibacteria, including Fsa02490Xyn and a second enzyme from F. sacchari, with apparent horizontal gene transfer within Fervidibacteria and between Fervidibacteria and thermophilic Bacillota. This study establishes Fsa02490Xyn as a hyperthermophilic GH10 enzyme with endo-β-1,4-xylanase activity and identifies a large clade of homologous GH10 enzymes within the class Fervidibacteria. Impact statement The depolymerization of xylan at high temperatures is important because this process limits the degradation of polysaccharides in nature and the synthesis of biofuels from plant wastes. Our study is also important because F. sacchari is one of only a few cultivated members of the Armatimonadota, which are polysaccharide-degradation specialists.

RevDate: 2025-08-29

Takano S, Takenawa S, Divya N, et al (2025)

Enrichment of Horizontally Transferred Gene Clusters in Bacterial Extracellular Vesicles via Non-Lytic Mechanisms.

The ISME journal pii:8243901 [Epub ahead of print].

Bacterial extracellular vesicles are emerging as key mediators of horizontal gene transfer, enhancing microbial adaptability. A critical factor determining the effectiveness of horizontal gene transfer is the fraction of vesicles containing specific functional genes. However, the proportion of containing specific DNA fragments has not been adequately determined, which hinders the understanding of the conditions and mechanisms that facilitate the incorporation of specific genes into the vesicles and possible evolutionary roles of vesicle-derived DNA. Here, we demonstrate that enrichment of horizontally transferred genes into bacterial extracellular vesicles is driven by cellular processes by profiling the DNA content of hundreds of individual vesicles using a microdroplet-based sequencing technique. This approach revealed unique DNA profiles in vesicles from the oral pathogen Porphyromonas gingivalis, pinpointing genomic regions related to DNA reorganization such as CRISPR-Cas clusters. Comparative genomic and phylogenetic analyses of Porphyromonas genomes revealed traces of horizontal gene transfer in vesicle-enriched genes. Modulating vesicle-biogenesis routes, quantitative real-time PCR revealed that this selective enrichment was driven by blebbing-driven DNA packaging mechanisms rather than stress-induced lysis. Applied to dental plaque-derived bacterial extracellular vesicles, the droplet-based approach reveled O-antigen biosynthetic genes, key for host-bacterial interactions, were prevalent in the vesicles from Alcaligenes faecalis, suggesting the vesicles from this bacterium can modulate pathogenicity in oral biofilms through targeted DNA packaging. These findings suggest the prevalence of functionally relevant gene clusters in bacterial extracellular vesicles in oral microbiota and their evolutionary roles as DNA cargoes for modulating phage-bacterial and host-bacterial interactions via horizontal gene transfer.

RevDate: 2025-08-28
CmpDate: 2025-08-29

Xu L, Jiao JY, Ling C, et al (2025)

Mobilome-mediated transcriptional activation of biosynthetic gene clusters and its impact on strain competitiveness in food fermentation microbiomes.

Microbiome, 13(1):191.

BACKGROUND: Microbial interactions are critical for maintaining the stability of food fermentation microbiomes, and mobile genetic elements (MGEs) significantly influence these interactions by horizontal gene transfer events. Although MGEs are known to facilitate horizontal gene transfer, their distribution among microorganisms and specific effects on microbial interactions remain poorly understood.

RESULTS: We analyzed 590 metagenomic and 42 metatranscriptomic samples from food fermentations, recovering 1133 metagenome-assembled genomes (MAGs). Our analysis revealed that MGEs were widely distributed in food fermentation microbiomes, with higher occurrence rates in Firmicutes (Bacillota: 0.71 ~ 11.85%) and Proteobacteria (Pseudomonadota: 0.47 ~ 11.05%). MGEs tended to be located adjacent to functional genes, particularly biosynthetic gene clusters (BGCs), with co-occurrence rates ranging from 9.41 to 23.99%. Furthermore, the transcriptional activity of BGCs was significantly correlated with the number of MGEs that were co-located with BGCs, which might enhance the competitiveness of strains. Variability in the diversity of MGEs that were co-located with BGCs was also evident at the strain level. Using Lactiplantibacillus plantarum as a case, we revealed that the strain-level differences in MGEs that were co-located with BGCs are positively correlated with the transcription of BGCs and competitiveness of strains within the species.

CONCLUSIONS: This study highlighted the role of MGEs in enhancing transcription of BGCs and facilitating strain competitiveness, providing new insights into how MGEs enhance the adaptability of microbial communities. Video Abstract.

RevDate: 2025-08-28

Skarlatoudi T, Anagnostou GM, Theodorakis V, et al (2025)

Escherichia coli Strains Originating from Raw Sheep Milk, with Special Reference to Their Genomic Characterization, Such as Virulence Factors (VFs) and Antimicrobial Resistance (AMR) Genes, Using Whole-Genome Sequencing (WGS).

Veterinary sciences, 12(8): pii:vetsci12080744.

The objective of this work was to deliver a comprehensive genetic characterization of a collection of E. coli strains isolated from raw sheep milk. To complete our purpose, the technique of whole-genome sequencing, coupled with bioinformatics and phenotypic characterization of antimicrobial resistance, was performed. These Gram-negative, facultative anaerobic bacteria belong to the family Enterobacteriaceae, together with other intestinal pathogens, such as Shigella spp. and Salmonella spp. Genetic analysis was carried out on all strains (phylogram, sequence types, VFs, AMR genes, and pangenome). The results showed the presence of various genetic traits that are related to virulence factors contributing to their pathogenic potential. In addition, genes conferring resistance to antibiotics were also detected and confirmed using phenotypic tests. Finally, the genome of the E. coli strains was characterized by the presence of several mobile genetic elements, thus facilitating the exchange of various genetic elements, associated with virulence and antimicrobial resistance, within and beyond the species, through horizontal gene transfer. Contaminated raw sheep milk with pathogenic E. coli strains is particularly alarming for cheese production in artisan dairies.

RevDate: 2025-08-28

El Samak M, Lotfy H, Sedeek AM, et al (2025)

Genomic Characterization of Marine Staphylococcus shinii Strain SC-M1C: Potential Genetic Adaptations and Ecological Role.

Microorganisms, 13(8): pii:microorganisms13081866.

Staphylococcus shinii (S. shinii) is a coagulase-negative species primarily associated with the degradation of organic matter, contributing to nutrient cycling in natural environments. This species has been mainly studied in clinical and terrestrial contexts, with no previous reports of its presence in marine environments. In this study, we report the first isolation of S. shinii from a marine habitat. The strain SC-M1C was isolated from the Red Sea sponge Negombata magnifica. Whole-genome sequencing confirmed its taxonomic identity as S. shinii. The genome uncovers potential adaptive characteristics that facilitate survival in marine ecosystems, comprising genes associated with osmoregulation, nutrient acquisition, stress response, and resistance to heavy metals. Moreover, multiple genomic islands and plasmids were identified, suggesting a potential role in horizontal gene transfer and environmental adaptability. The presence of biosynthetic gene clusters linked to non-ribosomal peptides, siderophores, and terpene production indicates potential for biochemical versatility beyond traditional metabolic expectations. This study presents the first genomic insights into S. shinii in a marine context, highlighting its ecological significance and adaptive mechanisms in a high-salinity environment. These findings expand our understanding of staphylococcal ecology beyond terrestrial and clinical origins and provide a foundation for exploring the role of S. shinii in marine microbial interactions and environmental resilience.

RevDate: 2025-08-28

Watanabe Y, Ishiga Y, N Sakata (2025)

The Role of Genomic Islands in the Pathogenicity and Evolution of Plant-Pathogenic Gammaproteobacteria.

Microorganisms, 13(8): pii:microorganisms13081803.

Genomic islands (GIs) including integrative and conjugative elements (ICEs), prophages, and integrative plasmids are central drivers of horizontal gene transfer in bacterial plant pathogens. These elements often carry cargo genes encoding virulence factors, antibiotic and metal resistance determinants, and metabolic functions that enhance environmental adaptability. In plant-pathogenic species such as Pseudomonas syringae, GIs contribute to host specificity, immune evasion, and the emergence of novel pathogenic variants. ICEclc and its homologs represent integrative and mobilizable elements whose tightly regulated excision and transfer are driven by a specialized transcriptional cascade, while ICEs in P. syringae highlight the ecological impact of cargo genes on pathogen virulence and fitness. Pathogenicity islands further modulate virulence gene expression in response to in planta stimuli. Beyond P. syringae, GIs in genera such as Erwinia, Pectobacterium, and Ralstonia underpin critical traits like toxin biosynthesis, secretion system acquisition, and topoisomerase-mediated stability. Leveraging high-throughput genomics and structural biology will be essential to dissect GI regulation and develop targeted interventions to curb disease spread. This review synthesizes the current understanding of GIs in plant-pathogenic gammaproteobacteria and outlines future research priorities for translating mechanistic insights into sustainable disease control strategies.

RevDate: 2025-08-28

Yang Y, Liu Y, Wang J, et al (2025)

Proteus mirabilis from Captive Giant Pandas and Red Pandas Carries Diverse Antimicrobial Resistance Genes and Virulence Genes Associated with Mobile Genetic Elements.

Microorganisms, 13(8): pii:microorganisms13081802.

Proteus mirabilis is a zoonotic pathogen that poses a growing threat to both animal and human health due to rising antimicrobial resistance (AMR). It is widely found in animals, including China's nationally protected captive giant and red pandas. This study isolated Proteus mirabilis from panda feces to assess AMR and virulence traits, and used whole-genome sequencing (WGS) to evaluate the spread of resistance genes (ARGs) and virulence genes (VAGs). In this study, 37 isolates were obtained, 20 from red pandas and 17 from giant pandas. Multidrug-resistant (MDR) strains were present in both hosts. Giant panda isolates showed the highest resistance to ampicillin and cefazolin (58.8%), while red panda isolates were most resistant to trimethoprim/sulfamethoxazole (65%) and imipenem (55%). Giant panda-derived strains also exhibited stronger biofilm formation and swarming motility. WGS identified 31 ARGs and 73 VAGs, many linked to mobile genetic elements (MGEs) such as plasmids, integrons, and ICEs. In addition, we found frequent co-localization of drug resistance genes/VAGs with MGEs, indicating a high possibility of horizontal gene transfer (HGT). This study provides crucial insights into AMR and virulence risks in P. mirabilis from captive pandas, supporting targeted surveillance and control strategies.

RevDate: 2025-08-28

Wu Z, Shao X, Q Wang (2025)

Antibiotics and Antibiotic Resistance Genes in the Environment: Dissemination, Ecological Risks, and Remediation Approaches.

Microorganisms, 13(8): pii:microorganisms13081763.

Global antibiotic use saturates ecosystems with selective pressure, driving mobile genetic element (MGE)-mediated antibiotic resistance gene (ARG) dissemination that destabilizes ecological integrity and breaches public health defenses. This review synthesizes the sources, environmental distribution, and ecological risks of antibiotics and ARGs, emphasizing the mechanisms of horizontal gene transfer (HGT) driven by MGEs such as plasmids, transposons, and integrons. We further conduct a comparative critical analysis of the effectiveness and limitations of antibiotics and ARGs remediation strategies for adsorption (biochar, activated carbon, carbon nanotubes), chemical degradation (advanced oxidation processes, Fenton-based systems), and biological treatment (microbial degradation, constructed wetlands). To effectively curb the spread of antimicrobial resistance and safeguard the sustainability of ecosystems, we propose an integrated "One Health" framework encompassing enhanced global surveillance (antibiotic residues and ARGs dissemination) as well as public education.

RevDate: 2025-08-28
CmpDate: 2025-08-28

Yang C, Liang W, Qin Y, et al (2025)

Mitochondrial Genome and RNA Editing Tissue Specificity of Centella asiatica.

Genes, 16(8): pii:genes16080953.

BACKGROUND: Centella asiatica, a medicinally important species that is rich in bioactive compounds, lacks a characterized mitochondrial genome, despite nuclear and chloroplast assemblies. We sequenced and annotated its mitochondrial genome to elucidate its genetic foundations and evolutionary mechanisms.

METHODS: Assembly using Illumina short-reads and Nanopore long-reads was used to characterize the mitochondrial genome. Analyses included structural characterization, codon usage bias, repetitive sequences, horizontal gene transfer (HGT), collinearity, and phylogeny. The resulting tissue-specific (root, stem, and leaf) long non-coding RNA (lncRNA) profiles identified RNA editing sites.

RESULTS: The complete mitochondrial genome (249,777 bp, 45.5% GC) comprises three circular contigs encoding 51 genes (33 protein-coding, 15 tRNA, and 3 rRNA). Comparative genomics revealed synteny with the Apiaceae family of plants and evidence of HGT. Phylogenetic analysis resolved taxonomic relationships within Apiales. We predicted that 547 RNA editing sites would be identified in its protein-coding genes. Tissue profiling identified 725 (root), 711 (stem), and 668 (leaf) editing sites, with >71% concordance to predictions. RNA editing-generated cryptic promoters/terminators occur in mitochondrial core function genes (e.g., ATP synthase, cytochrome c reductase/oxidase, ribosome large subunit, and cytochrome c biogenesis), exhibiting a lower frequency in the leaves compared to the roots and stems.

CONCLUSIONS: We provide the first complete mitochondrial genome assembly for C. asiatica, delineating its complex structure, tissue-modulated RNA editing, and evolutionary trajectory. This high-quality genomic resource establishes a foundation for molecular evolutionary studies and enhances the genomic toolkit for this pharmacologically significant species.

RevDate: 2025-08-28
CmpDate: 2025-08-28

Li R, C Bi (2025)

Comparative Genomic Analysis of Lactiplantibacillus plantarum: Insights into Its Genetic Diversity, Metabolic Function, and Antibiotic Resistance.

Genes, 16(8): pii:genes16080869.

Background/Objectives: Lactiplantibacillus plantarum is widely utilized in the fermentation industry and offers potential health benefits. However, large-scale comparative genomic analyses aimed at exploring its metabolic functions and conducting safety assessments are still lacking. Methods: In this study, we performed a comparative genomic analysis of 324 L. plantarum strains sourced from various origins and geographical locations. Results: The results revealed that L. plantarum possesses a total of 2403 core genes, of which 12.3% have an unknown function. The phylogenetic analysis revealed a mixed distribution from various origins, suggesting complex transmission pathways. The metabolic analysis demonstrated that L. plantarum strains can produce several beneficial metabolites, including lysine, acetate, and riboflavin. Furthermore, L. plantarum is highly capable of degrading various carbohydrates and proteins, increasing its adaptability. Further, we profiled the antimicrobial peptides (AMPs) in the genomes of L. plantarum. We identified a widely distributed AMP and its variants, presenting in a total of 280 genomes. In our biosafety assessment of L. plantarum, we identified several antibiotic resistance genes, such as Tet(M), ANT(6)-Ia, and mdeA, which may have potential for horizontal gene transfer within the Lactobacillaceae family. Conclusions: This study provides genomic insights into the genetic diversity, metabolic functions, antimicrobial properties, and biosafety of L. plantarum, underscoring its potential applications in biotechnology and environmental adaptation.

RevDate: 2025-08-28
CmpDate: 2025-08-28

Horodyska I, Kasperska P, Michalski K, et al (2025)

Natural Microbiota of Dogs and Cats as a Source and Vector of Resistance Genes-Clinical Significance.

International journal of molecular sciences, 26(16): pii:ijms26167717.

Antimicrobial resistance (AMR) presents a growing global threat, driven by widespread antibiotic misuse across human and veterinary medicine. Companion animals, particularly dogs and cats, harbor complex natural microbiota-including skin, mucosal, and gastrointestinal communities-that are essential to their health yet also serve as reservoirs of antibiotic resistance genes (ARGs). These ARGs can spread through horizontal gene transfer (HGT), especially during bacterial imbalances such as endogenous infections or surgical interventions, increasing the risk of difficult-to-treat infections. Documented zoonotic and anthroponotic transmissions of resistant strains such as MRSA, MRSP, and ESBL-producing E. coli highlight the bidirectional nature of ARG flow between animals and humans. This underscores the critical importance of the One Health approach, which promotes interdisciplinary collaboration to monitor, understand, and combat AMR across the human-animal-environment interface. Key mechanisms of ARG dissemination, the role of companion animal microbiota, and real-world examples of resistance transfer between species illustrate the complexity and urgency of addressing AMR. Targeted surveillance, rational antibiotic use, and public awareness are essential to preserving antimicrobial efficacy and safeguarding both human and animal populations.

RevDate: 2025-08-28

Sartori L, Furlan JPR, Sellera FP, et al (2025)

Clonal Diversity of Extraintestinal Pathogenic Escherichia coli Strains Isolated from Canine Urinary Tract Infections in Brazil.

Antibiotics (Basel, Switzerland), 14(8): pii:antibiotics14080819.

BACKGROUND/OBJECTIVES: Extraintestinal pathogenic Escherichia coli (ExPEC) strains, particularly those belonging to phylogenetic group B2, are clinically significant due to their frequent involvement in urinary tract infections (UTIs) and display antimicrobial resistance profiles. While the association of phylogroup B2 E. coli with human urinary tract infections is well established, the growing number of reports of ExPEC strains in canine UTIs highlights their clinical relevance in small animal medicine and raises concerns about their potential role in zoonotic transmission. This study investigated the microbiological and genomic features of E. coli strains isolated from dogs with UTIs in São Paulo, Brazil.

METHODS: Between March and May 2023, a total of 60 E. coli strains from canine UTIs were screened for antimicrobial susceptibility and phylotyping. Accordingly, four strains (6.6%) were identified as multidrug-resistant (MDR) or belonging to phylogroup B2 and, therefore, were submitted for characterization by whole-genome sequencing.

RESULTS: The four E. coli strains exhibited diverse antimicrobial resistance profiles, including resistance to third- and fourth-generation cephalosporins and fluoroquinolones. Phylogenetic groups B1, B2, and G, and sequence types (ST) 73, ST224, ST1193, and ST12960 were identified. The resistome included clinically important β-lactam resistance genes, such as blaCTX-M-55 and blaCMY-2, as well as mutations in the quinolone-resistance-determining region. Virulence factors associated with ExPEC pathogenesis, including adhesion, iron acquisition, immune evasion, and toxin, were detected. Plasmid sequences were identified as carrying antimicrobial resistance and virulence genes, highlighting the potential for horizontal gene transfer.

CONCLUSIONS: Our findings underscore the importance of genomic surveillance in companion animals to better understand the epidemiology of ExPEC strains and monitor the spread of MDR strains.

RevDate: 2025-08-28

Sassi A, Basher NS, Kirat H, et al (2025)

The Role of the Environment (Water, Air, Soil) in the Emergence and Dissemination of Antimicrobial Resistance: A One Health Perspective.

Antibiotics (Basel, Switzerland), 14(8): pii:antibiotics14080764.

Antimicrobial resistance (AMR) has emerged as a planetary health emergency, driven not only by the clinical misuse of antibiotics but also by diverse environmental dissemination pathways. This review critically examines the role of environmental compartments-water, soil, and air-as dynamic reservoirs and transmission routes for antibiotic-resistant bacteria (ARB) and resistance genes (ARGs). Recent metagenomic, epidemiological, and mechanistic evidence demonstrates that anthropogenic pressures-including pharmaceutical effluents, agricultural runoff, untreated sewage, and airborne emissions-amplify resistance evolution and interspecies gene transfer via horizontal gene transfer mechanisms, biofilms, and mobile genetic elements. Importantly, it is not only highly polluted rivers such as the Ganges that contribute to the spread of AMR; even low concentrations of antibiotics and their metabolites, formed during or after treatment, can significantly promote the selection and dissemination of resistance. Environmental hotspots such as European agricultural soils and airborne particulate zones near wastewater treatment plants further illustrate the complexity and global scope of pollution-driven AMR. The synergistic roles of co-selective agents, including heavy metals, disinfectants, and microplastics, are highlighted for their impact in exacerbating resistance gene propagation across ecological and geographical boundaries. The efficacy and limitations of current mitigation strategies, including advanced wastewater treatments, thermophilic composting, biosensor-based surveillance, and emerging regulatory frameworks, are evaluated. By integrating a One Health perspective, this review underscores the imperative of including environmental considerations in global AMR containment policies and proposes a multidisciplinary roadmap to mitigate resistance spread across interconnected human, animal, and environmental domains.

RevDate: 2025-08-28

Meradji S, Basher NS, Sassi A, et al (2025)

The Role of Water as a Reservoir for Antibiotic-Resistant Bacteria.

Antibiotics (Basel, Switzerland), 14(8): pii:antibiotics14080763.

Water systems serve as multifaceted environmental pools for antibiotic-resistant bacteria (ARB) and resistance genes (ARGs), influencing human, animal, and ecosystem health. This review synthesizes current understanding of how antibiotics, ARB, and ARGs enter surface, ground, and drinking waters via wastewater discharge, agricultural runoff, hospital effluents, and urban stormwater. We highlight key mechanisms of biofilm formation, horizontal gene transfer, and co-selection by chemical stressors that facilitate persistence and spread. Case studies illustrate widespread detection of clinically meaningful ARB (e.g., Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae) and mobile ARGs (e.g., sul1/2, tet, bla variants) in treated effluents, recycled water, and irrigation return flows. The interplay between treatment inefficiencies and environmental processes underscores the need for advanced treatment technologies, integrated monitoring, and policy interventions. Addressing these challenges is critical to curbing the environmental dissemination of resistance and protecting human and ecosystem health.

RevDate: 2025-08-28

Yinsai O, Yuantrakul S, Srisithan P, et al (2025)

Genomic Insights into Emerging Multidrug-Resistant Chryseobacterium indologenes Strains: First Report from Thailand.

Antibiotics (Basel, Switzerland), 14(8): pii:antibiotics14080746.

Background: Chryseobacterium indologenes, an environmental bacterium, is increasingly recognized as an emerging nosocomial pathogen, particularly in Asia, and is often characterized by multidrug resistance. Objectives: This study aimed to investigate the genomic features of clinical C. indologenes isolates from Maharaj Nakorn Chiang Mai Hospital, Thailand, to understand their mechanisms of multidrug resistance, virulence factors, and mobile genetic elements (MGEs). Methods: Twelve C. indologenes isolates were identified, and their antibiotic susceptibility profiles were determined. Whole genome sequencing (WGS) was performed using a hybrid approach combining Illumina short-reads and Oxford Nanopore long-reads to generate complete bacterial genomes. The hybrid assembled genomes were subsequently analyzed to detect antimicrobial resistance (AMR) genes, virulence factors, and MGEs. Results: C. indologenes isolates were primarily recovered from urine samples of hospitalized elderly male patients with underlying conditions. These isolates generally exhibited extensive drug resistance, which was subsequently explored and correlated with genomic determinants. With one exception, CMCI13 showed a lower resistance profile (Multidrug resistance, MDR). Genomic analysis revealed isolates with genome sizes of 4.83-5.00 Mb and GC content of 37.15-37.35%. Genomic characterization identified conserved resistance genes (blaIND-2, blaCIA-4, adeF, vanT, and qacG) and various virulence factors. Phylogenetic and pangenome analysis showed 11 isolates clustering closely with Chinese strain 3125, while one isolate (CMCI13) formed a distinct branch. Importantly, each isolate, except CMCI13, harbored a large genomic island (approximately 94-100 kb) carrying significant resistance genes (blaOXA-347, tetX, aadS, and ermF). The absence of this genomic island in CMCI13 correlated with its less resistant phenotype. No plasmids, integrons, or CRISPR-Cas systems were detected in any isolate. Conclusions: This study highlights the alarming emergence of multidrug-resistant C. indologenes in a hospital setting in Thailand. The genomic insights into specific resistance mechanisms, virulence factors, and potential horizontal gene transfer (HGT) events, particularly the association of a large genomic island with the XDR phenotype, underscore the critical need for continuous genomic surveillance to monitor transmission patterns and develop effective treatment strategies for this emerging pathogen.

RevDate: 2025-08-27
CmpDate: 2025-08-27

Pozzi CM, Gaiti A, A Spada (2025)

Climate change and plant genomic plasticity.

TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik, 138(9):231.

Genome adaptation, driven by mutations, transposable elements, and structural variations, relies on plasticity and instability. This allows populations to evolve, enhance fitness, and adapt to challenges like climate change. Genomes adapt via mutations, transposable elements, DNA structural changes, and epigenetics. Genome plasticity enhances fitness by providing the genetic variation necessary for organisms to adapt their traits and survive, which is especially critical during rapid climate shifts. This plasticity often stems from genome instability, which facilitates significant genomic alterations like duplications or deletions. While potentially harmful initially, these changes increase genetic diversity, aiding adaptation. Major genome reorganizations arise from polyploidization and horizontal gene transfer, both linked to instability. Plasticity and restructuring can modify Quantitative Trait Loci (QTLs), contributing to adaptation. Tools like landscape genomics identify climate-selected regions, resurrection ecology reveals past adaptive responses, and pangenome analysis examines a species' complete gene set. Signatures of past selection include reduced diversity and allele frequency shifts. Gene expression plasticity allows environmental adaptation without genetic change through mechanisms like alternative splicing, tailoring protein function. Co-opted transposable elements also generate genetic and regulatory diversity, contributing to genome evolution. This review consolidates these findings, repositioning genome instability not as a mere source of random error but as a fundamental evolutionary engine that provides the rapid adaptive potential required for plant survival in the face of accelerating climate change.

RevDate: 2025-08-27

Zhao E, Li Y, Zhang J, et al (2025)

A Review on the Degradation of Antibiotic Resistance Genes During Composting of Livestock Manure.

Toxics, 13(8):.

As emerging pollutants, antibiotic resistance genes (ARGs) have been recognized as originating from diverse sources. Among these, the use of livestock feed and veterinary drugs was identified as the primary source of ARGs in livestock manure. ARGs were found to be widely distributed in global environments, particularly in agriculture-related soils, water bodies, and the atmosphere, posing potential threats to ecological environments and human health. This paper reviewed the degradation mechanisms of ARGs during aerobic composting of livestock manure and the safety evaluation of compost products. Aerobic composting was demonstrated to be an effective method for degrading ARGs, primarily through mechanisms such as high-temperature elimination of ARG-carrying microorganisms, reduction in host bacterial abundance, and inhibition of horizontal gene transfer. Factors including the physicochemical properties of the composting substrate, the use of additives, and the presence of antibiotic and heavy metal residues were shown to influence the degradation efficiency of ARGs, with compost temperature being the core factor. The safety of organic fertilizers encompassed multiple aspects, including heavy metal content, seed germination index, and risk assessments based on ARG residues. The analysis indicated that deficiencies existed in areas such as the persistence of thermotolerant bacteria carrying ARGs, the dissemination of extracellular antibiotic resistance genes (eARGs), and virus-mediated gene transfer. Future research should focus on (1) the removal of thermotolerant bacteria harboring ARGs; (2) the decomposition of eARGs or the blocking of their transmission pathways; (3) the optimization of ultra-high temperature composting parameters; and (4) the analysis of interactions between viruses and resistant hosts. This study reviews the mechanisms, influencing factors, and safety assessment of aerobic composting for degrading ARGs in livestock manure. It not only deepens the understanding of this important environmental biotechnology process but also provides a crucial knowledge base and practical guidance for effectively controlling ARG pollution, ensuring agricultural environmental safety, and protecting public health. Additionally, it clearly outlines the key paths for future technological optimization, thus holding significant implications for the environment, agriculture, and public health.

RevDate: 2025-08-27

Gopal C, Al Tarify H, Pirhadi E, et al (2025)

Membrane Stress Enhances Specific PQS-Lipid Interactions That Drive Bacterial Outer Membrane Vesicle Biogenesis.

Membranes, 15(8):.

Gram-negative bacteria use outer membrane vesicles (OMVs) for toxin trafficking, immune interference, horizontal gene transfer, antibiotic protection, and cell-cell communication. Despite their direct contribution to many pathogenesis-related behaviors, our understanding of how OMVs are produced remains surprisingly incomplete. The Bilayer Couple model describes the induction of OMV formation resulting from the preferential accumulation of small molecules in the outer leaflet of the membrane, resulting in leaflet expansion and membrane bending. Previous work has highlighted the importance of the structure of the Pseudomonas Quinolone Signal (PQS) in driving OMV formation, but the nature of interactions with membrane lipids remains unclear. Our recent in silico analysis suggested that a new interaction, between the PQS ring nitrogen and Lipid A, is critical for PQS function. Here, we used chemical analogs to interrogate the importance of specific PQS functional groups in its ability to stimulate OMV biogenesis. We demonstrated that OMV induction requires the presence of all PQS functional groups together. Further modeling uncovered that PQS prefers interaction with the outer leaflet of the membrane, consistent with its unique ability to drive OMV biogenesis. This was explained by much greater hydrogen bond formation between PQS and Lipid A. Interestingly, the preference of PQS for the outer leaflet coincided with that leaflet becoming crowded. Thus, the initial insertion of PQS into the outer leaflet would be expected to encourage local accumulation of more PQS to drive the induction of membrane curvature and subsequent OMV formation.

RevDate: 2025-08-27

Wang Y, Jiang L, Zhou F, et al (2025)

The hidden dancers in water: the symbiotic mystery of Legionella pneumophila and free-living amoebae.

Frontiers in microbiology, 16:1634806.

Legionella pneumophila, a Gram-negative bacillus, is the primary etiological agent of Legionnaires' disease, a severe respiratory infection. The symbiotic relationship between L. pneumophila and free-living amoebae (FLAs), particularly Acanthamoeba spp., represents a critical intersection of microbial ecology and human pathogenesis. This symbiosis provides Legionella with a protective intracellular niche, enhancing its resistance to biocides, increasing its pathogenicity, and facilitating horizontal gene transfer. These interactions not only boost the environmental persistence and dissemination of L. pneumophila but also elevate the risk of human exposure through contaminated drinking water systems. This review delves into the sophisticated survival strategies employed by L. pneumophila within host cells, including evasion of endocytic pathways, inhibition of phagosome maturation and acidification, and prevention of phagosome-lysosome fusion. By elucidating these mechanisms, we underscore the critical need for in-depth research into the Legionella-amoebae symbiosis and its broader implications for public health. Additionally, we address the challenges and strategies for mitigating environmental risks, emphasizing the importance of innovative approaches to ensure water system safety and prevent pathogen transmission.

RevDate: 2025-08-27

Pacheco-Acosta S, Castro-Toro G, Rojas-Villalobos C, et al (2025)

Exploring the eco-evolutionary role of plasmids and defense systems in 'Fervidacidithiobacillus caldus' extreme acidophile.

Frontiers in microbiology, 16:1610279.

Plasmids are major drivers of microbial evolution, enabling horizontal gene transfer (HGT) and facilitating adaptation through the dissemination of relevant functional genes and traits. However, little is known about plasmid diversity and function in extremophiles. 'Fervidacidithiobacillus caldus', a meso-thermo-acidophilic sulfur oxidizer, is a key player in sulfur cycling in natural and industrially engineered acidic environments. Here, we present a bioinformatic analysis of the plasmidome, and associated anti-mobile genetic element (anti-MGE) defense systems (defensome), across genomes of this species and metagenomes from diverse natural and industrial settings harboring 'F. caldus'. We identified >30 distinct plasmids, representing five consistent replication-mobilization families. Plasmids ranged in size between 2.5-65 kb, with gene content and plasmid modularity scaling with element size and copy numbers inversely correlating with size. Plasmids carried variable numbers of hypothetical proteins and transposases, with annotated cargo genes reflecting functional differentiation by habitat. Defensome profiling revealed over 50 anti-MGE systems in sequenced 'F. caldus' isolates, including diverse restriction-modification systems, CRISPR-Cas types IV-A and V-F, and widespread abortive infection and composite defense systems such as Wadjet, Gabija, and Zorya. In environmental populations, an inverse relationship was observed between defensome complexity and plasmidome abundance and diversity, underscoring a pivotal role of the host defensome in modulating persistence, compatibility, and overall plasmid diversity across 'F. caldus' populations. Yet, other plasmids appeared decoupled from both host abundance and defensome complexity, suggesting potential host shifts, environmental persistence, or differential replication under suboptimal growth conditions for the host. Altogether, these findings point to a modular, functionally diverse adaptive plasmidome shaped by environmental pressures, by the interplay with the host's defensome, and likely also by other eco-evolutionary processes at play in natural environments. While these associations are compelling, causal relationships remain to be experimentally validated. These insights broaden our understanding of mobile genetic elements in extreme environments and provide a foundation for plasmid-based vector design and synthetic biology applications in acidophiles, with direct implications to biomining and environmental remediation.

RevDate: 2025-08-27

She T, Tan D, Balcazar JL, et al (2025)

Phage-mediated horizontal transfer of Salmonella enterica virulence genes with regulatory feedback from the host.

iMeta, 4(4):e70042.

Phage-mediated horizontal transfer of virulence genes can enhance the transmission and pathogenicity of Salmonella enterica (S. enterica), a process potentially regulated by its regulatory mechanisms. In this study, we explored the global dynamics of phage-mediated horizontal transfer in S. enterica and investigated the role of its regulatory mechanisms in transduction. A total of 5178 viral sequences encoding 12 S. enterica virulence genes were retrieved from the Integrated Microbial Genomes and Virome (IMG/VR) database, alongside 466,136 S. enterica genomes from EnteroBase. Virulence genes, including iacP (acyl carrier protein), mgtB (P-type Mg[2+] transporter), misL (autotransporter porin), and fliC (flagellar filament protein), were widely distributed in phages and S. enterica across North America, Europe, and Asia. Phylogenetic analysis revealed close genetic affinity between phage- and bacterial-encoded virulence genes, suggesting shared ancestry and historical horizontal gene transfer events. The global regulator carbon storage regulator A (csrA) was highly conserved and ubiquitous in S. enterica. Overexpression of csrA inhibited prophage cyclization and release by upregulating the prophage cI repressor during horizontal gene transfer. Overall, these findings enhance our understanding of phage-mediated horizontal transfer of virulence genes, explore new areas of bacterial regulators that inhibit gene exchange and evolution by affecting phage life cycles, and offer a novel approach to controlling the transmission of phage-mediated S. enterica virulence genes.

RevDate: 2025-08-26

Ji Q, Zhu J, Hou G, et al (2025)

Antibiotic stress alters lysogeny-lysis dynamics and drives phage-mediated transfer of antibiotic resistance genes in the activated sludge process.

Journal of hazardous materials, 497:139659 pii:S0304-3894(25)02578-6 [Epub ahead of print].

The spread of antibiotic resistance genes (ARGs) in wastewater treatment systems poses a significant public health concern, yet the role of bacteriophages (phages), particularly temperate phages, in mediating horizontal gene transfer (HGT) of ARGs under antibiotic stress remains poorly understood. This study investigated the effects of escalating ciprofloxacin (CIP; 0-200 μg/L)-selected as a representative antibiotic due to its frequent occurrence and persistence in wastewater-on phage lysogeny-lysis dynamics and phage-mediated ARG transfer in a laboratory-scale activated sludge reactor. Integrating metaviromic and metagenomic analysis revealed that the phage-mediated ARG-HGT events mainly occurred at the highest CIP concentration stage (200 μg/L), indicating that high-level antibiotic stress is essential for triggering significant ARG transfer. Notably, all these HGT events were associated with temperate phages. The HGT-associated ARGs may confer host resistance to antibiotics, as supported by the ARG expression and antibiotic resistance activity experiment. Although temperate dynamics generally shifted toward lysogeny under escalating stress, most of the temperate phages involved in ARG-HGT became more active at higher CIP concentration stages, which may facilitate host survival under stress conditions.

RevDate: 2025-08-23

Kumar M, Ballamoole KK, Shetty VA, et al (2025)

Perspective on integrated multi-omics approaches and constraint-based modeling to explore metabolic functionality on the evolution of bacterial antibiotic resistance.

Microbial pathogenesis pii:S0882-4010(25)00724-7 [Epub ahead of print].

Antimicrobial resistance (AMR) is one of the greatest threats to humanity globally as it has been escalated by the over-prescription and usage of antibiotics for both humans and animals. AMR occurs when the bacteria develop a way of resisting the antimicrobial compounds, thus leading to increased mortality rates, health expenses, and issues of handling infections. The development of AMR occurs through mutations of bacterial genes or through horizontal gene transfer that results in increased minimum inhibitory concentration and bacterial tolerance. Perspectives from evolutionary trade-offs and constraint-based modeling were used to analyze the relationship between mutational changes and antimicrobial resistance. The idea of "adaptive landscape" helps in explaining how microbial traits develop based on selective forces, and the "dimensionality of phenotypic states" looks at how resistance occurs in various biological systems. The omics approaches give multi-dimensional data to focus further on bacterial adaptation factors and explore future antimicrobial resistance trends. Information on condition-dependent resistance and the weakness of the resistant strains is obtained when involving constraint-based modeling and resequencing of the genome. It also involves bacterial metabolic plasticity under antibiotic pressure and provides fresh approaches to combat antimicrobial resistance. This perspective emphasizes the importance of new strategies highlighting the availability of multiple omics approaches to understand the bacterial resistance mechanisms and construct early therapeutic approaches.

RevDate: 2025-08-26
CmpDate: 2025-08-26

Jiang Q, Zhuang W, Zhang Z, et al (2025)

Reactive chlorine species inhibiting interspecies spread of antibiotic resistance via disrupting donor - Recipient cells and regulating plasmid conjugation genes.

Journal of hazardous materials, 495:138864.

Current drinking water treatment plant (DWTP) disinfection technologies face limitations, allowing plasmid-mediated antibiotic resistance genes (ARGs) transfer to occur among viable but nonculturable (VBNC) bacteria, heightening the risk of antibiotic-resistant infections. While UV/Chlorine has been adopted to curb ARGs abundance, its impacts on the interspecies transfer of ARG-carrying plasmids remain hardly explored. This study investigated how reactive chlorine species (RCS) in the UV/Chlorine system inhibited the transfer of antibiotic resistance from antibiotic-resistant Escherichia coli (AR E. coli) to Bacillus subtilis (B.S) by inactivating both donor and recipient strains and regulating plasmid conjugation genes. RCS reduced plasmid transfer frequencies by 2.1-log and 3.2-log compared to UV or chlorine alone. By impairing [•]OH scavenging ability, it led to ROS accumulation in AR E. coli, disrupting cellular energy metabolism and DNA repair, ultimately causing DNA degradation and membrane damage, resulting in AR E. coli inactivation rather than entering the VBNC state. Additionally, RCS induced structural and intracellular disruption in B.S, compromising its capacity for plasmid uptake and stable maintenance. Finally, RCS inhibited plasmid horizontal transfer while enhancing vertical transfer, with its damage to outer membrane proteins further restricting interspecies plasmid conjugation transfer. This study provides novel insights for DWTPs to better control ARGs interspecies transfer and improve drinking water safety.

RevDate: 2025-08-23

Zhaxybayeva O, CL Nesbø (2025)

Impact of Horizontal Gene Transfer on Adaptations to Extreme Environments.

Journal of molecular biology pii:S0022-2836(25)00469-3 [Epub ahead of print].

Horizontal (or lateral) gene transfer - an acquisition of genetic material not associated with the organismal reproduction - is known to alter genomes of most, if not all, living organisms. There is mounting evidence for the importance of gene exchange in organismal adaptations to new or changing environmental conditions. In comparison to accumulation of de novo mutations, acquisition of a gene already beneficial in the environment is fast and less costly, and thus an advantageous, way to adjust to survival and growth in new conditions. Adaptation to extreme environments at the boundaries of habitat conditions beyond which cellular integrity, metabolism and growth are not possible, is not an exception. Here we review the impact of horizontal gene transfer on organismal adaptations to natural and human-made extreme environments. This includes thermophiles living at high temperatures, psychrophiles found at low temperatures, acidophiles inhabiting high acidity environments, alkaliphiles thriving at high pH, halophiles found in high salt environments, xerophiles that can tolerate extremely low water availability, oligotrophes thriving at low nutrient availability, piezophiles inhabiting high pressure environments, and organisms that can withstand high levels of ionizing radiation. We also discuss the challenges and future directions for deciphering genetic determinants and horizontal gene transfer events of extremophiles' adaptations.

RevDate: 2025-08-22

Yoshimoto S, Hattori M, Inoue S, et al (2025)

Identification of toluene degradation genes in Acinetobacter sp. Tol 5.

Journal of bioscience and bioengineering pii:S1389-1723(25)00192-6 [Epub ahead of print].

Microbial degradation of aromatic compounds provides sustainable solutions for environmental remediation and bioconversion. Acinetobacter sp. Tol 5 is notable for its strong adhesiveness and potential as a biocatalyst for toluene degradation; however, its toluene metabolic pathway has not been fully elucidated. In this study, genomic analysis identified a cluster of genes in Tol 5 highly similar to the well-known tod operon of Pseudomonas putida, encoding enzymes responsible for toluene metabolism. Phylogenetic analyses indicated that these tod genes, unusual among Acinetobacter species, were likely acquired through horizontal gene transfer. Transcriptomic analyses revealed that todF and todC1 are co-transcribed, while the adjacent fadL2 gene, encoding a putative outer membrane transporter corresponding to P. putida todX, is independently transcribed. Growth experiments using gene-knockout mutants revealed that TodC1, the large subunit of dioxygenase, is essential for growth on toluene, whereas FadL2 is not essential. Growth curves on each carbon source further showed that the todC1 knockout mutant could metabolize benzoate, but not toluene or benzene, confirming that the TOD pathway is the primary route for toluene and benzene degradation in Tol 5. The identification of the functional TOD pathway, which is unique within Acinetobacter, provides genetic and biochemical insights for the development of Tol 5 as an efficient immobilized biocatalyst for the bioremediation and bioconversion of aromatic compounds.

RevDate: 2025-08-21

Fang J, Chen Z, Yu Z, et al (2025)

Biochar suppresses conjugative transfer of antibiotic resistance genes in manure-amended soils.

The ISME journal pii:8239162 [Epub ahead of print].

The environmental dissemination of antibiotic resistance genes (ARGs), particularly in manure-amended soils, poses a growing threat to public health due to the potential transfer of ARGs to humans and animals. Effective strategies are urgently needed to mitigate ARG spread in agricultural settings. Biochar, an eco-friendly soil amendment, shows promise for pollution control, yet its role in suppressing ARG horizontal gene transfer remains unclear. Here, metagenomic analysis showed that manure application significantly increased the relative abundance of ARGs in soil microbiota, whereas biochar amendment reduced it. To determine whether biochar suppresses ARG dissemination by inhibiting horizontal transfer, we established a soil microcosm. Manure application increased the conjugative transfer ratio by 3-fold, whereas biochar effectively suppressed this transfer reducing it to levels observed in unamended soils. Cell sorting and 16S rRNA gene amplicon sequencing demonstrated that biochar treatment reduced the diversity of transconjugant pools at both phylum and genus level. Transconjugants were primarily affiliated with Pseudomonadota, Bacillota, and Actinomycetota, with Massilia, Delftia, and Ammoniphilus being the most abundant genera in biochar treatment soil. Mechanistic investigations revealed that biochar-mediated inhibition of ARG transfer was linked to reduced ATP energy supply, decreased reactive oxygen species production, and lower cell membrane permeability, and diminished bioavailability of heavy metals and antibiotics. Additionally, biochar altered soil enzyme activity and microbial community structure, further limiting ARG dissemination. The findings provide insights into biochar-induced mitigation of ARG spread in manure-amended soils and highlight its potential as an effective strategy for controlling environmental ARG transmission.

RevDate: 2025-08-21

Zhai ZQ, Yang LK, Zhu LB, et al (2025)

Early Life Exposure to Manure-Fertilized Soil Shapes the Gut Antibiotic Resistome.

Environment & health (Washington, D.C.), 3(8):931-941.

The global rise of antimicrobial resistance (AMR) presents a pressing public health challenge with agricultural practices such as the use of manure fertilization, excessive antibiotic use in livestock, and the irrigation of crops with contaminated water contributing to the spread of antibiotic resistance genes (ARGs). Despite growing concerns, the pathways through which ARGs migrate from environmental reservoirs to animal microbiomes are poorly understood. In this study, we raised mice from birth in pig manure-fertilized red (Ultisols) and black (Mollisols) soils or unfertilized controls, sampling their gut microbiomes at 8 weeks, to show that early life exposure to manure-fertilized soil profoundly shapes the gut antibiotic resistome in mice. Application of organic manure significantly enriched tetracycline-resistant ARGs in both red and black soils. Mice living in these environments harbored markedly higher abundances of ARGs, particularly the tet-(Q) gene, compared to those in nonfertilized environments. Notably, Muribaculaceae and Bacteroidaceae were identified as key hosts of tet-(Q), with evidence suggesting a horizontal gene transfer between these families. These findings indicate that manure fertilization not only increases ARG abundance in soils but also facilitates its transfer to animal microbiomes, thereby amplifying the risk of AMR dissemination. This research underscores the importance of improved agricultural management practices to mitigate the environmental transmission of AMR.

RevDate: 2025-08-21

Trejo-Meléndez VJ, J Contreras-Garduño (2025)

Master of Puppets: How Microbiota Drive the Nematoda Ecology and Evolution?.

Ecology and evolution, 15(8):e71549.

In recent decades, the microbiota has emerged as a key driver of biological functions in metazoans, and nematodes are no exception. Advances in genomic technologies have enabled detailed exploration of nematode-microbiota interactions, revealing compelling insights. However, much of our current understanding is derived from studies on the model organism Caenorhabditis elegans, where the microbiota's role in shaping host phenotypes and genotypes has been extensively characterized. These studies have uncovered the selective pressures influencing the function, structure, and assembly of the microbiota, highlighting the dynamic interplay between nematodes and their associated microbial communities. Despite these findings, the ecological and evolutionary implications of the microbiota in nematodes remain underappreciated. Emerging evidence indicates that the microbiota can modulate nematode life-history traits and mediate trade-offs among fitness components. Moreover, mechanisms such as horizontal gene transfer from bacteria have been shown to alter nematode phenotypes and genotypes, facilitating adaptation to novel or challenging environments. In this review, we integrate life-history theory into the nematodes-microbiota interactions, offering a framework to identify the mechanisms driving phenotypic variation in nematodes. Understanding these processes is essential for uncovering the evolutionary and ecological bases of metazoan diversification, with the microbiota acting as a crucial source of phenotypic and genetic variability.

RevDate: 2025-08-20

Bui-Nguyen TA, Huynh TB, H Tran-Van (2025)

Molecular Epidemiology of Acute Hepatopancreatic Necrosis Disease: A Review.

Developmental and comparative immunology pii:S0145-305X(25)00133-8 [Epub ahead of print].

Acute hepatopancreatic necrosis disease (AHPND) is one of the major shrimp diseases worldwide which affects global economy up to 44 billion USD from 2010 to 2016. The causative agent of AHPND is the binary toxin PirAB, a toxin that causes sloughing effect on shrimp hepatopancreatic cells. This toxin is encoded by pirAB[vp] gene located within a 5.5-kb composite transposon Tn6264, on a ∼70-kb plasmid pVA carried by Vibrio parahaemolyticus. Up to date, the pathogenesis and epidemiological links between AHPND-causing strains are still unclear. Therefore, this review aims to collect achieved results about the distribution, origin, transmission, and antibiotic resistance status of AHPND-causing strains, the molecular mechanism of PirAB toxin, and the mobile genetic elements that promote the spread of AHPND to provide valuable insights for future studies. Phylogenetic studies on AHPND reveal its evolutionary history, transmission routes, and genetic variations, with findings suggesting diverse origins of AHPND strains across different regions, facilitated by horizontal gene transfer and adaptation mechanisms in V. parahaemolyticus populations. Antimicrobial resistance profiles of AHPND-causing strains are also diverse and prevalent, particularly in Vietnam, South Korea, and Thailand, encompassing antibiotics like ampicillin, amoxicillin, sulfadiazine sodium, streptomycin, colistin, cefalexin, erythromycin, ceftazidime, and neomycin, raising concerns regarding multidrug resistance. PirAB toxin might function through the pore-forming activity of PirB[vp] and the receptor-binding activity of PirA[vp], as predicted by Cry toxin model, while its expression is regulated by the quorum sensing system in V. parahaemolyticus. The pVA plasmid and the composite transposon Tn6264 both facilitates the dissemination of AHPND-causing strains, while the evolutionary mechanisms of these elements have not been widely understood. Transcriptomic and metabolomic studies also identify numerous differentially expressed genes in shrimp infected by AHPND-causing V. parahaemolyticus, and its immunity is also dependent on developmental stage and gut microbiota.

RevDate: 2025-08-20

Mariault L, Puginier C, Keller J, et al (2025)

Mechanisms, Detection, and Impact of Horizontal Gene Transfer in Plant Functional Evolution.

The Plant cell pii:8238793 [Epub ahead of print].

Horizontal gene transfers (HGT) have been observed across the tree of life. While their adaptive importance in bacteria is conspicuous, the occurrence of HGT and their evolutionary significance in Eukaryotes has only recently started to be considered. In this review, we explore the extent of HGT in the plant kingdom, indicating the widespread occurrence of microbe - plant HGT and Plant - Plant HGT. We propose mechanisms that mediate these transfers, and detail the methods available to identify and test the robustness of putative HGT using both sequence-based and phylogenomic approaches. Exploring recently sequenced plant genomes across the green lineage has revealed hundreds of such HGT. We discuss the impact of these transfers on plant adaptation and functional diversification. In the future, expanding the phylogenomic scrutinization of the plant kingdom should reveal the full extent of HGT. In situ sequencing and combinations of synthetic biology and experimental evolution may allow catching ongoing HGT and testing the functional relevance of such events.

RevDate: 2025-08-20

Meza C, Sepulveda B, Flores-Castañón N, et al (2025)

Genomic basis and functional characterization of the exopolysaccharide production by a thermotolerant Bacillus isolated from Tolhuaca hot spring.

Frontiers in microbiology, 16:1622325.

Bacillus licheniformis Tol1, a thermotolerant bacterial strain isolated from the Tolhuaca hot spring in Chile, was investigated for its genomic features and the functional properties of its exopolysaccharide (EPS). The whole-genome sequencing revealed ∼4.25 Mbp genome with a GC content of 45.9% and a rich repertoire of genes associated with environmental stress adaptation, antibiotic resistance, sporulation, biofilm formation, and EPS biosynthesis, including the presence of epsD and epsC. The strain also harbored intact prophage elements and a Type I-A CRISPR-Cas system, indicating potential horizontal gene transfer and genome plasticity. Confocal microscopy revealed robust biofilm formation at 45-55°C under neutral to slightly alkaline pH, with strong EPS matrix development. EPS production was optimized using OFAT and Response Surface Methodology (RSM), achieving a yield of 2.11 g L[-1] under optimized conditions, which was further validated using an Artificial Neural Network (ANN) model (R [2] = 0.9909). The EPS exhibited promising antioxidant activity and significant emulsification potential across various vegetable oils, which were comparable or superior to commercial bacterial EPS xanthan gum. Notably, the EPS also showed cytotoxic effects against AGS gastric adenocarcinoma cells, reducing viability by 38.38 and 37% at 50-100 μg μL[-1] concentrations, respectively, suggesting potential anticancer activity. Altogether, the study highlights B. licheniformis Tol1 as a multifunctional thermophile with valuable biotechnological potential, particularly for applications in food, pharmaceutical, and biomedical industries.

RevDate: 2025-08-20

Cerda-Herrera JD, Zhang H, Wafula EK, et al (2025)

Chromosome level assembly and annotation of Cuscuta campestris Yunck. ("field dodder"), a model parasitic plant.

G3 (Bethesda, Md.) pii:8238363 [Epub ahead of print].

We present the first chromosome-level genome assembly and annotation for the genus Cuscuta, a twining and leafless parasitic plant of the morning glory family (Convolvulaceae). C. campestris, the study species, is a widely studied model parasite, due in part to its worldwide occurrence as a weed of agricultural and natural plant communities. The species has served as a model parasite for studies of parasite biology, haustorium development, growth responses to chemical and light stimuli, gene content and expression, horizontal gene transfer, interspecies RNA movement, and has a recently developed transformation system. The 505 Mb (1C) genome is assembled into 31 chromosomes and supports annotation of 47,199 protein-coding genes, 214 small RNA loci (including 146 haustoria-specific miRNAs), and 3,238 interspecies mobile mRNA loci. C. campestris is a recent tetraploid with a high retention of duplicated genes and chromosomes, and less than 8% nucleotide divergence between homoeologous chromosomes. We also show that transformation of C. campestris with the RUBY marker system allows visualization of transformed Cuscuta-derived fluorescent mobile molecules that have entered the host stem. This genome will be of value for scientists performing fundamental research in a wide range of molecular, developmental, population and evolutionary biology, as well as a research tool for studying interspecies mobile molecules, generating genetic markers for species and genotype identification, and for the development of highly specific herbicides.

RevDate: 2025-08-20
CmpDate: 2025-08-20

Saffari Natanzi A, Poudineh M, Karimi E, et al (2025)

Innovative approaches to combat antibiotic resistance: integrating CRISPR/Cas9 and nanoparticles against biofilm-driven infections.

BMC medicine, 23(1):486.

The increasing prevalence of antibiotic-resistant bacterial infections is a major global health concern, with biofilms playing a key role in bacterial persistence and resistance. Biofilms provide a protective matrix that limits antibiotic penetration, enhances horizontal gene transfer, and enables bacterial survival in hostile environments. Conventional antimicrobial therapies are often ineffective against biofilm-associated infections, necessitating the development of novel therapeutic strategies. The CRISPR/Cas9 gene-editing system has emerged as a revolutionary tool for precision genome modification, offering targeted disruption of antibiotic resistance genes, quorum sensing pathways, and biofilm-regulating factors. However, the clinical application of CRISPR-based antibacterials faces significant challenges, particularly in efficient delivery and stability within bacterial populations. Nanoparticles (NPs) present an innovative solution, serving as effective carriers for CRISPR/Cas9 components while exhibiting intrinsic antibacterial properties. Nanoparticles can enhance CRISPR delivery by improving cellular uptake, increasing target specificity, and ensuring controlled release within biofilm environments. Recent advances have demonstrated that liposomal CRISPR-Cas9 formulations can reduce Pseudomonas aeruginosa biofilm biomass by over 90% in vitro, while gold nanoparticle carriers enhance editing efficiency up to 3.5-fold compared to non-carrier systems. These hybrid platforms also enable co-delivery with antibiotics, producing synergistic antibacterial effects and superior biofilm disruption. Additionally, they can facilitate co-delivery of antibiotics or antimicrobial peptides, further enhancing therapeutic efficacy. This review explores the synergistic integration of CRISPR/Cas9 and nanoparticles in combating biofilm-associated antibiotic resistance. We discuss the mechanisms of action, recent advancements, and current challenges in translating this approach into clinical practice. While CRISPR-nanoparticle hybrid systems hold immense potential for next-generation precision antimicrobial therapies, further research is required to optimize delivery platforms, minimize off-target effects, and assess long-term safety. Understanding and overcoming these challenges will be critical for developing effective biofilm-targeted antibacterial strategies.

RevDate: 2025-08-19

Sibbald SJ, Lawton M, Maclean C, et al (2025)

Pangenome biology and evolution in harmful algal-bloom-forming pelagophytes.

Current biology : CB pii:S0960-9822(25)00964-9 [Epub ahead of print].

In prokaryotes, lateral gene transfer (LGT) is a key mechanism leading to intraspecies variability in gene content and the phenomenon of pangenomes. In microbial eukaryotes, however, the extent to which LGT-driven pangenomes exist is unclear. Pelagophytes are ecologically important marine algae that include Aureococcus anophagefferens-a species notorious for causing harmful algal blooms. To investigate genome evolution across Pelagophyceae and within Ac. anophagefferens, we used long-read sequencing to produce high-quality genome assemblies for five strains of Ac. anophagefferens (52-54 megabase pairs [Mbp]), a telomere-to-telomere assembly for Pelagomonas calceolata (32 Mbp), and the first reference genome for Aureoumbra lagunensis (41 Mbp). Using comparative genomics and phylogenetics, we show remarkable strain-level genetic variation in Ac. anophagefferens, with a pangenome (23,356 orthogroups) that is 81.1% core and 18.9% accessory. Although gene content variation within Ac. anophagefferens does not appear to be largely driven by recent prokaryotic LGTs (2.6% of accessory orthogroups), 368 orthogroups were acquired from bacteria in a common ancestor of all analyzed strains and are not found in P. calceolata or Au. lagunensis. A total of 1,077 recent LGTs from prokaryotes and viruses were identified within Pelagophyceae overall, constituting 3.5%-4.0% of the orthogroups in each species. This includes genes likely contributing to the ecological success of pelagophytes globally and in long-lasting harmful blooms.

RevDate: 2025-08-19

Zhang J, Chen J, Wang C, et al (2025)

Nitrate input enriched the antibiotic resistance genes in lake sediments by shaping co-host community and promoting horizontal gene transfer.

Journal of hazardous materials, 497:139580 pii:S0304-3894(25)02499-9 [Epub ahead of print].

The impact of various non-antibiotic factors on antibiotic resistance has garnered widespread attention. However, there has been little investigation into whether the coexistence of nutrients with antibiotic resistance genes (ARGs) in aquatic ecosystems contributes to the increasing abundance of ARGs. We employed a microcosm experiment and metagenomic analysis to investigate the impact of nitrate on ARG profiles in lake sediments. Our results revealed that increased nitrate input correspondingly elevated the abundance of sediment ARGs, virulence factor genes (VFGs), mobile genetic elements (MGEs), and nitrate reduction genes (NRGs). Among the metagenome-assembled genomes (MAGs) harboring ARGs found by binning analysis, nitrate inputs increased the abundance of 78.4 % ARG-carried MAGs, especially in genera Nitrosomonas and Sulfuriomonas. All MAGs carrying ARGs simultaneously encoded NRGs, suggesting that ARG-NRG co-hosts are important factors for ARG proliferation. Co-localization and Pearson's correlation analyses suggested that nitrate input most likely accelerated the acquisition of ARGs by particular bacterial taxa via horizontal gene transfer (HGT). Genes involved in HGT, including those related to reactive oxygen species production, membrane permeability, ATP synthesis, and pili synthesis, were also upregulated by nitrate input, thus potentially enhancing ARG transfer. Based on the partial least squares path modeling analysis, abundances of genes involved in HGT (r = 0.43) and ARG-NRG co-hosts (r = 0.41) had the highest direct positive impact on the ARG abundance. Our study suggests the increased nitrate levels may drive the dissemination of antibiotic resistance, consequently affecting human health.

RevDate: 2025-08-19

Wang X, Chen Z, Liu C, et al (2025)

Type I-F CRISPR-associated transposons contribute to genomic plasticity in Shewanella and mediate efficient programmable DNA integration.

Microbial genomics, 11(8):.

The genome plasticity of species and strains in the genus Shewanella is closely associated with the diverse mobile genetic elements embedded in its genomes. One mobile element with potential for accurate and efficient DNA insertion in Shewanella is the type I-F3 CRISPR-associated transposon (I-F3 CAST). However, relatively little is known about the distribution and ecological significance of I-F3 CASTs and whether they could be suitable as a tool for targeted genetic manipulation in situ. To better understand the distribution of I-F3 CASTs in Shewanella, we analysed 602 Shewanella genomes. We found that I-F3 CASTs were present in 12% of all genomes, although differences in both gene arrangement and integration locus were observed. These Shewanella I-F3 CASTs carried up to 89 cargo genes, which were associated with diverse functions, including defence, resistance and electron transfer, demonstrating an important role in genomic diversification and ecological adaptation. We tested whether the I-F3 CAST present in Shewanella sp. ANA-3 enhanced gene insertion, both in situ and in a heterologous host. We observed I-F3 CAST-mediated crRNA-targeted integration of the supplied genes into the pyrF locus in Shewanella sp. ANA-3. Heterologous gene insertion with high integration efficiency in Escherichia coli was also demonstrated using a simplified version of ANA-3 I-F3 CAST. Altogether, this work highlights the important role of I-F3 CASTs in promoting genomic plasticity of the Shewanella genus and demonstrates the gene-editing capability of ANA-3-CAST both endogenously and heterologously.

RevDate: 2025-08-18

Suzuki H, Moriguchi K, Shintani M, et al (2025)

Insights from public database sequences related to the replication initiation protein TrfA of the IncP-1 plasmid RK2.

Plasmid pii:S0147-619X(25)00014-9 [Epub ahead of print].

Replicon typing identifies sequences similar to known DNA replication initiators and is widely used to detect specific plasmid groups (e.g., IncP-1) in genome and metagenome sequencing data. However, the characteristics of these homologous sequences in public databases have not been systematically assessed, making it difficult to determine whether detecting a specific replicon type reliably indicates the presence of a particular plasmid group. Here, we conducted amino acid sequence alignments to identify sequences similar to the replication initiation protein TrfA of the IncP-1 plasmid RK2 in the NCBI non-redundant (nr) database. In the nr nucleotide database, TrfA-matched nucleotide sequences were found across diverse taxonomic groups and replicons, including complete and partial plasmids and chromosomes. In total, 76 protein sequences from the reference plasmid RK2 were screened against the nucleotide sequences of the trfA-harboring plasmids to identify candidate IncP-1 plasmids. TrfA-related proteins, originating from bacterial chromosomes, plasmids, and phages, were selected from the nr amino acid database and used to infer phylogenetic trees. Our phylogenetic analyses reveal that TrfA homologs have diverged through vertical inheritance within IncP-1 and horizontal gene transfer across replicons and taxa. These findings caution against overreliance on single-gene replicon typing to infer plasmid group identity from sequence data.

RevDate: 2025-08-18

Sadler MC, Wietz M, Mino S, et al (2025)

Genomic diversity and adaptation in Arctic marine bacteria.

mBio [Epub ahead of print].

Arctic marine bacteria experience seasonal changes in temperature, salinity, light, and sea ice cover. Time-series and metagenomic studies have identified spatiotemporal patterns in Arctic microbial communities, but a lack of complete genomes has limited efforts to identify the extent of genomic diversity in Arctic populations. We cultured and sequenced the complete genomes of 34 Arctic marine bacteria to identify patterns of gene gain, loss, and rearrangement that structure genomes and underlie adaptations to Arctic conditions. We found that the most abundant lineage in the Arctic (SAR11) is comprised of diverse species and subspecies, each encoding 50-150 unique genes. Half of the 16 SAR11 genomes harbor a genomic island with the potential to enhance survival in the Arctic by utilizing the osmoprotectant and potential methyl donor glycine betaine. We also cultured and sequenced four species representing an uncultured family of Pseudomonadales, four subspecies of Pseudothioglobus (SUP05), a genus of high GC Puniceispirillales (SAR116), and a family of low GC SAR116. Time-series 16S rRNA amplicon data indicate that this culture collection represents up to 60% of the marine bacterial community in Arctic waters. Their genomes provide insights into the evolutionary processes that underlie bacterial diversity and adaptation to Arctic waters.IMPORTANCEGenetic diversity has limited efforts to assemble and compare whole genomes from natural populations of marine bacteria. We developed a cultivation-based population genomics approach to culture and sequence the complete genomes of bacteria from the Arctic Ocean. Cultures and closed genomes obtained in this study represent previously uncultured families, genera, and species from the most abundant lineages of bacteria in the Arctic. We report patterns of gene gain, loss, rearrangement, and adaptation in the dominant lineage (SAR11), as well as the size, composition, and structure of genomes from several other groups of marine bacteria. This work demonstrates the potential for cultivation-based high-throughput genomics to enhance understanding of the processes underlying genomic diversity and adaptation.

RevDate: 2025-08-18

Teixeira P, Ramos M, Rivière R, et al (2025)

Genomic epidemiology and resistome dynamics of Enterobacter species in a Portuguese Open Air Laboratory: the emergence of the FRI-8 carbapenemase.

Frontiers in microbiology, 16:1593872.

Interconnected reservoirs contribute to the global spread of antimicrobial resistance (AMR), including carbapenem- and colistin-resistant Enterobacterales, highlighting the need for a One Health approach. We assessed the genomic epidemiology, diversity and AMR mechanisms of Enterobacter spp. across interconnected human, animal, plant, and environmental reservoirs in a Portuguese Open Air Laboratory. Over a one year monitoring period, samples from 12 different compartments were collected and processed using selective media to isolate Enterobacter spp., which were subjected to antibiotic susceptibility testing, whole-genome sequencing and subsequent analyses to identify AMR determinants, characterize plasmids and phylogenetic relationships. We established a collection of 61 Enterobacter isolates spanning nine species and 32 sequence types, including 16 novel ones, across nine compartments (river water, wastewater, soil, manure, feed, air, farmers, pigs, wild animals), reflecting the diversity and ubiquity of Enterobacter species. Core-genome analysis revealed eight genetic clusters, suggesting clonal transmission across compartments. In total, 29 antibiotic resistance genes were detected across all isolates. Notably, this is the first documentation of bla FRI-harbouring Enterobacterales in European environmental settings and the first to describe bla FRI, bla IMI and mcr-10 genes in Portugal. bla FRI-8 was detected in all E. vonholyi isolates (n = 17), located on four different IncFII(Yp) plasmids, and bla IMI-6 in an E. asburiae isolate, flanked by IS3 family transposases. E. vonholyi and the bla IMI-6-harbouring E. asburiae isolate were resistant to carbapenems. A mcr-10.1 gene was identified in an E. roggenkampii isolate on an IncFII(pECLA) plasmid. These plasmids exhibited high sequence similarity with global counterparts, indicating potential for horizontal gene transfer. Other antimicrobial resistance genes included qnrE1, sul1, and aadA2. Our findings underscore the importance of Enterobacter as vectors for AMR and the critical role of environmental compartments in its dissemination, reinforcing the importance of adopting a One Health approach to fully understand AMR dynamics.

RevDate: 2025-08-18

Li X, Chen H, Chen Y, et al (2025)

In-silico Analysis of a Novel MCR-1.1 Variant on an IncX4 Plasmid Attenuating Colistin Resistance in Multidrug-Resistant Escherichia coli ST131.

Infection and drug resistance, 18:4053-4066.

INTRODUCTION: The emergence of mcr-1.1-mediated colistin resistance in Escherichia coli poses a significant threat to last-resort antibiotic therapy. This study investigates a novel variant of mcr-1.1 found in a highly virulent E. coli ST131 strain isolated from a pediatric patient with severe aplastic anemia and recurrent infections.

METHODS: Blood samples were collected from a 4-year-old patient, and the E. coli isolate underwent antimicrobial susceptibility testing, multi-locus sequence typing, serotyping, and whole-genome sequencing. In-silico analyses included molecular docking and molecular dynamics simulations to assess the structural and functional impact of the mcr-1.1 variant. Horizontal gene transfer experiments evaluated plasmid mobility.

RESULTS: The E. coli ST131 isolate harboured a mcr-1.1 gene located on a stable IncX4 plasmid and exhibited a multidrug-resistant phenotype. A missense mutation (T797C) led to an F265L substitution in the MCR-1.1 enzyme, reducing its phosphoethanolamine transferase activity. This mutation likely impairs lipid A modification, decreasing colistin resistance. Molecular modeling supported the reduced binding affinity of the mutated MCR-1.1 for lipid A. The plasmid demonstrated a horizontal transfer frequency of 1.3 × 10[-]². Phylogenetic analysis showed close relatedness to global ST131 clones.

CONCLUSION: This novel mcr-1.1 variant potentially restores colistin susceptibility in a globally prevalent E. coli lineage. The findings highlight a unique resistance attenuation mechanism and offer a promising avenue for restoring colistin efficacy. Further in-vivo validation is warranted to explore therapeutic strategies exploiting such mutations.

RevDate: 2025-08-18

Gómez-Rubio E, Arana L, Vicario-Martín R, et al (2025)

Exploring Inhibition of Bacterial Conjugation Coupling Protein TrwB: Novel Ligands to Fight Antimicrobial Resistance Spread.

ACS omega, 10(31):34645-34658.

Bacterial conjugation is the most sophisticated mechanism for horizontal gene transfer. Conjugative plasmids allow the recipient bacterium to acquire new traits from the donor, such as antimicrobial resistance (AMR). Among the proteins involved in the plasmid transfer machinery, the Type IV Coupling Protein (T4CP) links the relaxosome and the Type IV Secretion System (T4SS). However, despite their biological relevance and their potential as a target to control AMR, only a few T4CPs have been exhaustively studied. The archetype of the T4CP family is the coupling protein of the conjugative plasmid R388, TrwB. The inhibition of TrwB ATPase activity or oligomerization with small-molecule modulators is expected to control the transfer of R388, contributing to combat AMR spread. Following a drug repurposing approach, we have combined in silico screening studies, molecular dynamics (MD) simulations, and in vitro bacterial conjugation assays to identify a small collection of compounds that selectively decrease the frequency of conjugation of the plasmid R388 (30-40%). Our results suggest that this inhibition is the result of the specific interaction of these drugs with TrwB. The search for conjugation inhibitors, via the inactivation of proteins such as T4CPs, rises as a strategy to advance in solutions to combat the silent pandemic of AMR.

RevDate: 2025-08-15

Li H, Yan Y, Shi Y, et al (2025)

Mechanisms underlying the role of Fe3O4 in enhancing antibiotic degradation and mitigating the spread of antibiotic resistance in aquaculture sediment: Coupling dissimilatory iron reduction with methanogenesis.

Journal of hazardous materials, 496:139526 pii:S0304-3894(25)02442-2 [Epub ahead of print].

Ferric oxides play a critical role in transforming organic contaminants within anaerobic aquaculture sediments; however, their effect on the removal of antibiotics and antibiotic resistance genes (ARGs) remains unexplored. This study revealed that the addition of Fe3O4 significantly promoted microbial Fe(III) reduction, SMX degradation, and methanogenesis by enhancing metabolic activity and facilitating electron transfer. While nutrient supplementation similarly improved SMX removal, it notably increased ARG abundance, unlike Fe3O4, which effectively suppressed ARGs. Although the presence of the electron shuttle AQDS in Fe3O4-amended systems further stimulated dissimilatory iron reduction, no additional benefit to SMX degradation was observed. Inhibition of methanogenesis reduced SMX degradation by 48 %, whereas Fe3O4 supplementation enriched the methane metabolic pathway, suggesting that SMX removal occurred through a conductive network involving Fe3O4 and methanogens. Moreover, Fe3O4 supplementation induced significant shifts in bacterial community composition, enhanced antioxidase activity, and reduced reactive oxygen species levels. These alterations were associated with the repression of genes related to horizontal gene transfer and a decrease in ARG hosts. Overall, these results indicate that Fe3O4 serves as an effective conductor, enhancing antibiotic degradation and limiting ARG propagation in aquaculture sediments.

RevDate: 2025-08-15

McDonagh F, Ryan K, Kovářová A, et al (2025)

Identification of blaESBL- and blaCARBA- Positive Multi-Drug Resistant Mixta calida Isolates from Distinct Human Hosts.

International journal of medical microbiology : IJMM, 320:151669 pii:S1438-4221(25)00025-6 [Epub ahead of print].

OBJECTIVE: This study aimed to investigate the identification of blaCARBA-positive multidrug-resistant Mixta calida isolates from human hosts and to elucidate their genomic determinants in a species-wide context.

METHODS: Two carbapenemase-producing M. calida isolates were received by the Galway Reference Laboratory Service in Ireland between June and July 2024. One isolate originated from a sputum sample, while the other was recovered from a routine screening rectal swab. Initial identification was performed using MALDI-ToF mass spectrometry, with genomic confirmation via 16S rRNA sequencing, digital DNA-DNA hybridization, and Average Nucleotide Identity analysis. Antimicrobial susceptibility testing was conducted using a MicroScan panel, following EUCAST and CLSI guidelines. Whole-genome sequencing, plasmid replicon typing, and antibiotic-resistance-gene and virulence-factor profiling were employed. Comparative analysis included all additional canonical M. calida genomes from NCBI database.

RESULTS: Both Irish isolates were taxonomically placed as M. calida and exhibited multidrug resistance against penicillins, cephalosporins, monobactams and ertapenem. The acquired genes blaKPC-3, blaOXA-9, and blaTEM-122 were detected on plasmid-borne contigs, indicating horizontal acquisition. Seven plasmid replicon types were shared between the two isolates. Both plasmid replicons and acquired antimicrobial-resistance-genes (ARGs) were seldomly identified across the species. Phylogenetic inference based on core genome analysis identified a monophyletic cluster, suggesting a single introductory event.

CONCLUSION: This study documents a dual occurrence of blaCARBA-positive M. calida in human colonisation and infection. The findings highlight the potential for horizontal-gene-transfer to drive the emergence of multidrug-resistant profiles in the species, underscoring the need for enhanced surveillance, diagnostic precision, and targeted infection control strategies to mitigate public health risks.

IMPACT STATEMENT: This study reports blaESBL and blaCARBA-positive multi-drug resistant Mixta calida isolates from distinct human hosts. Genomic analysis revealed the co-occurrence of plasmid-borne resistance genes blaKPC-3, blaOXA-9, and blaTEM-122. Species-wide phylogenetic analysis grouped the two isolates into a monophyletic cluster, suggesting a single introductory event.

RevDate: 2025-08-15

Anonymous (2025)

Pathway to Independence - an interview with Sonya Widen.

Development (Cambridge, England), 152(16):.

Sonya Widen is a Postdoctoral Fellow in Alejandro Burga's lab at the Vienna BioCenter, Austria. She is interested in large DNA transposons called Polintons (or Mavericks) that facilitate horizontal gene transfer across nematodes and how they and other transposons with viral-like properties can influence development and evolution. Sonya is part of the 2025 cohort of Development's Pathway to Independence programme, which aims to support postdocs in their transition towards establishing their own labs and securing independent funding. We spoke to Sonya online to learn about her research interests in genome evolution, hopes for the programme and plans for her future lab.

RevDate: 2025-08-18

Kiu R, Darby EM, Alcon-Giner C, et al (2025)

Impact of early life antibiotic and probiotic treatment on gut microbiome and resistome of very-low-birth-weight preterm infants.

Nature communications, 16(1):7569.

Preterm infants (<37 weeks' gestation) are commonly given broad-spectrum antibiotics due to their risk of severe conditions like necrotising enterocolitis and sepsis. However, antibiotics can disrupt early-life gut microbiota development, potentially impairing gut immunity and colonisation resistance. Probiotics (e.g., certain Bifidobacterium strains) may help restore a healthy gut microbiota. In this study, we investigated the effects of probiotics and antibiotics on the gut microbiome and resistome in two unique cohorts of 34 very-low-birth-weight, human-milk-fed preterm infants - one of which received probiotics. Within each group, some infants received antibiotics (benzylpenicillin and/or gentamicin), while others did not. Using shotgun metagenomic sequencing on 92 longitudinal faecal samples, we reconstructed >300 metagenome-assembled genomes and obtained ~90 isolate genomes via targeted culturomics, allowing strain-level analysis. We also assessed ex vivo horizontal gene transfer (HGT) capacity of multidrug-resistant (MDR) Enterococcus using neonatal gut models. Here we show that probiotic supplementation significantly reduced antibiotic resistance gene prevalence, MDR pathogen load, and restored typical early-life microbiota profile. However, persistent MDR pathogens like Enterococcus, with high HGT potential, underscore the need for continued surveillance. Our findings underscore the complex interplay between antibiotics, probiotics, and HGT in shaping the neonatal microbiome and support further research into probiotics for antimicrobial stewardship in preterm populations.

RevDate: 2025-08-14

Chen Y, Liu S, Ouyang T, et al (2025)

Reshaping the antibiotic resistance genes in plastisphere upon deposition in sediment-water interface: Dynamic evolution and propagation mechanism.

Journal of hazardous materials, 496:139532 pii:S0304-3894(25)02448-3 [Epub ahead of print].

Microplastics (MPs) could provide unique niches for microbiota and aggravate their gravity, leading to vertical travel from waters to sediments. Although the plastisphere functions as hotspots for antibiotic resistance genes (ARGs) enrichment, the dynamic evolution and mechanisms of ARGs remain poorly understood when MPs deposited at sediment-water interface (SWI). Herein, this study investigated the dynamic response and reshaping mechanism of ARGs in plastisphere across SWI. It reveals that in deep waters, the ARGs abundance in biodegradable polylactic acid (PLA) plastisphere was higher than non-biodegradable polyethylene terephthalate (PET). However, when plastisphere deposited at SWI from deep waters, the ARGs abundance in PET plastisphere was increased by 45.71-65.10 %, while that decreased by 52.15-53.25 % in PLA. The plastisphere across SWI possessed higher species richness and diversity, more complex interactions, and more key species regulating ARGs compared to deep waters. During sedimentation, the horizontal gene transfer potential was enhanced in PET plastisphere but inhibited PLA. In addition, the function response related to oxidative stress response, cell membrane permeability, and energy metabolism may be underlying mechanisms in regulating ARGs propagation during the travel of plastisphere across SWI. This study highlights the critical roles of SWI in regulating the ARGs propagation in the traveling plastisphere.

RevDate: 2025-08-16

Liu G, Mao C, Li Q, et al (2025)

Comparative genomic analysis reveals the adaptive traits of Ralstonia spp. in aquatic environments.

Frontiers in microbiology, 16:1625651.

Ralstonia spp. are highly adaptable bacteria that are widely distributed across diverse environments. Here, we isolated four Ralstonia pickettii (R. pickettii) genomes from cultures of Dolichospermum spp., and using a comparative genomic framework of 228 Ralstonia genomes. We performed phylogenetic analyses that grouped them into water, soil, plant, and human-associated clades based on their predominant isolation habitats. Fluorescence in situ hybridization revealed minimal physical interactions between R. pickettii and cyanobacterial cells, indicating a commensal or independent ecological relationship. Distinct differences in carbohydrate-active enzymes (CAZymes) and secondary metabolite profiles were observed between water and human-associated dominant groups compared to plant-associated dominant groups, highlighting potential niche-specific adaptations. The water-associated dominant groups harbored antibiotic resistance genes, including CeoB and OXA-type β-lactamase genes. These genes are typically linked to human-associated strains, suggesting potential horizontal gene transfer or shared selective pressures, and the gene content of T3SS is reduced. Notably, water-associated dominant groups exhibited a unique pyrimidine degradation pathway, potentially enabling the utilization of exogenous pyrimidines to support survival in nutrient-limited aquatic environments. We propose that the gene content loss of T3SS and the acquisition of specialized metabolic pathways reflect adaptive strategies of Ralstonia spp. for thriving in aquatic free-living niches.

RevDate: 2025-08-17

Sadikalay S, Cavé L, Ducat C, et al (2025)

Tracking Enterobacteria, microbiomes, and antibiotic resistance genes from waste to soil with repeated compost applications.

PloS one, 20(8):e0329200.

The dissemination of antibiotic resistant bacteria (ARB) and genes is one factor responsible for the increasing antibiotic resistance and the environment plays a role in resistance spread. Animal excreta can contribute to the contamination of the environment with ARBs and antibiotics and in some cases, environmental bacteria under antibiotic pressure may acquire antibiotic resistance genes (ARGs) from ARBs by horizontal gene transfer. In Guadeloupe, a French overseas department, organic amendments derived from human and animal waste are widely used in soil fertilization, but their contribution to antibiotic resistance remains unknown. The objective of this study was to evaluate the impact of composting animal and human raw waste and the repeated application of their derived-composts, on the fate of ARGs and antibiotic resistant Enterobacteria, for the first time, in tropical soils of Guadeloupe used for vegetable production. An unculturable approach was used to characterize the bacterial community composition and ARG content from raw waste to composts. A cultivable approach was used to enumerate Enterobacteria, and resistant isolates were further characterized phenotypically and genotypically. Based on this original approach, we demonstrated that the raw poultry droppings exhibited a depletion of Escherichia and Shigella populations during the composting treatment, which was corroborated by the results on the culturable resistant Enterobacteria. Significant differences in the abundance of ARGs were also observed, with some gene levels increasing or decreasing after composting. In addition, other bacterial genera potentially involved in the spread of antimicrobial resistance were identified. Taken together, these results demonstrate that successive applications of raw waste-derived-composts from green waste, sewage sludge, and poultry droppings reshape the Enterobacterial community and influences the abundance of ARGs, with some gene levels increasing or decreasing, in Guadeloupe's tropical vegetable production soils.

RevDate: 2025-08-13

Vesel N, Stare E, Štefanič P, et al (2025)

Naturally competent bacteria and their genetic parasites - A battle for control over horizontal gene transfer?.

FEMS microbiology reviews pii:8233665 [Epub ahead of print].

Host-mediated natural competence for transformation of DNA and mobile genetic element (MGE)-driven conjugation and transduction are key modes of horizontal gene transfer. While these mechanisms are traditionally believed to shape bacterial evolution by enabling the acquisition of new genetic traits, numerous studies have elucidated an antagonistic relationship between natural transformation and MGEs. A new role of natural transformation as a chromosome curing mechanism has now been proposed. Experimental data, along with mathematical models, suggest that transformation can eliminate deleterious MGEs. Supporting this hypothesis, MGEs have been shown to use various mechanisms to decrease or block transformability, such as disrupting competence genes, regulating the development of competence, hindering DNA uptake machinery, producing DNases that target the exogenous (transforming) DNA, and causing lysis of competent cells. A few examples of synergistic relationships between natural transformation and MGEs have also been reported, with natural transformation facilitating MGE transfer and phages enhancing transformation by supplying extracellular DNA through lysis and promoting competence via kin discrimination. Given the complexity of the relationships between natural transformation and MGEs, the balance between antagonism and synergy likely depends on specific selection pressures in a given context. The evidence collected here indicates a continuous conflict over horizontal gene transfer in bacteria, with semiautonomous MGEs attempting to disrupt host-controlled DNA acquisition, while host competence mechanisms work to resist MGE interference.

RevDate: 2025-08-13

Mougin J, Labreuche Y, Boulo V, et al (2025)

Antibiotic Use in Oyster Hatcheries Promotes Rapid Spread of a Highly Transferable and Modular Resistance Plasmid in Vibrio.

The ISME journal pii:8233092 [Epub ahead of print].

Plasmids play a key role in the horizontal gene transfer of antibiotic resistance genes, particularly in aquaculture where ARG-carrying Vibrio bacteria are frequently detected. Given the expansion of global aquaculture and its reliance on antibiotics, we investigated how these practices influence the emergence, dynamics, and spread of ARGs, focusing on Magallana gigas hatcheries - the world's most widely farmed shellfish. Among the three antibiotics tested, only chloramphenicol led to a pronounced selection and dissemination of chloramphenicol-resistant Vibrio isolates. Resistance was mediated by catA2, located in a highly modular, insertion sequence- and transposase-rich region of a conjugative plasmid, alongside tet(B). This plasmid was closely related to emerging pAQU-type plasmids unreported in Europe. pAQU-MAN, derived from Marine ANtimicrobial resistance, is a low-copy, highly transferable plasmid that rapidly spread throughout the hatchery following CHL treatment. Though naturally found in commensal Vibrio, it exhibited a broad host range, transferring efficiently to both oyster- and human-pathogenic Vibrio strains, as well as to E. coli, with high conjugation rates. Additionally, it remained stable in Vibrio hosts and was transmitted from oyster parents to progenies, even in the absence of antibiotic. It eventually disappeared from the microbial community associated to adults. Our findings highlight that antibiotic use in oyster hatcheries can select for highly modular and transferable multidrug-resistant plasmids, posing a risk of environmental dissemination, although their limited persistence in juvenile oyster reduces the likelihood of transmission to humans. We discuss the human and ecological factor driving pAQU-MAN spread and control in aquaculture settings.

RevDate: 2025-08-16

Gichure J, Hald T, E Buys (2025)

Exploring the Genetic Diversity, Virulence and Antimicrobial Resistance of Diarrhoeagenic Escherichia coli From Southern Africa Using Whole-Genome Data.

Public health challenges, 4(3):e70098.

Introduction: Previous studies, including our research, provide critical insights on the contamination of food, water and environment in the Southern African Development Community (SADC) with diarrhoeagenic Escherichia coli (DEC). This study used whole-genome sequencing to investigate the genetic diversity, virulence-associated factors and antimicrobial resistance (AMR) patterns of DEC isolated from children under 5 years old and food sources in Maputo and compared these findings with publicly available DEC genome assemblies from the Southern Africa region. Methods: Whole-genome sequence data from 11 DEC isolates from food, children under 5 and water sources in Maputo, Mozambique, were analysed alongside 125 publicly available DEC genomic assemblies from the SADC region. The latter were retrieved from the EnteroBase database (http://enterobase.warwick.ac.uk) and included isolates previously collected from food, animals and environmental sources. Genomic analyses were performed using the online pipelines provided by the Centre for Genomic Epidemiology (CGE), Denmark. Unsupervised hierarchical clustering was applied to visualize patterns in genetic diversity, AMR, virulence-associated genes and plasmid content using the R software. Results: Clustering based on single nucleotide polymorphism (SNP) and core genome multilocus sequence typing (cgMLST) alleles revealed associations based on geographic locations, sample niche, pathovar and O:H antigen, pointing to evolutionary relatedness between the clades with principal coordinate analysis uncovering this accounted for 27.55% of the genetic diversity. Virulence-associated genes encoding for attaching and effacing (eae) (63.97%), heat-labile toxin (LT) (25.00%) and Shiga toxin 1 (Stx1) (15.44%) were most abundant, with an inverse association between genes encoding for the presence of LT and eae. Resistance to folate pathway antagonists (sulfamethoxazole-55.9%), β-lactamases (amoxicillin, ampicillin and piperacillin-all 54.4%) and aminoglycoside (streptomycin-55.1%) was most abundant. Conclusions: The study revealed region-specific lineages, evidence of horizontal gene transfer and the clustering patterns suggest both localized and cross-border transmission. The study provides insightful evidence on DEC transmission patterns associated with antimicrobial and disinfectant resistance and associated virulence factors.

RevDate: 2025-08-12

Qing Y, Liao Z, An D, et al (2025)

Comparative genomics reveals the genetic diversity and plasticity of Clostridium tertium.

Journal of applied microbiology pii:8232670 [Epub ahead of print].

AIMS: Clostridium tertium, increasingly recognized as the emerging human pathogen frequently isolated from environmental and clinical specimens, remains genetically underexplored despite its clinical relevance. This study aims to explore the genetic characteristics of C. tertium by genomic analysis.

METHODS AND RESULTS: This study presented a comprehensive genomic investigation of 45 C. tertium strains from the GenBank database. Genome sizes (3.27-4.55 Mbp) and coding gene counts varied markedly across strains. Phylogenetic analyses based on 16S rRNA gene and core genome uncovered distinct intra-species lineages, including evolutionarily divergent clusters likely shaped by niche specialization. Pan-genomic analysis confirmed an open genome, with accessory and strain-specific genes enriched in functions related to environmental adaptation and regulation. Functional annotation further identified diverse virulence factor genes (e.g. clpP, nagK) and antibiotic resistance genes (e.g. vatB, tetA(P)) co-occurring with mobile genetic elements (MGEs), suggesting that horizontal gene transfer (HGT) may be a key driver of genome plasticity in C. tertium. Notably, one-third of the strains carried CRISPR-Cas systems, indicating the defense potential against exogenous genetic elements.

CONCLUSIONS: C. tertium exhibited extensive genetic diversity and genome plasticity, probably driven by MGE-mediated HGT, defense mechanisms of CRISPR-Cas systems, and functional adaptation related to virulence and resistance. These traits may underlie its ability to colonize diverse environments and acquire pathogenicity and resistance.

RevDate: 2025-08-19

Mazzamurro F, Touchon M, Charpentier X, et al (2025)

Impact of Natural Transformation on the Acquisition of Novel Genes in Bacteria.

Molecular biology and evolution, 42(8):.

Natural transformation is the only process of gene exchange under the exclusive control of the recipient bacteria. It has often been considered as a source of novel genes, but quantitative assessments of this claim are lacking. To investigate the potential role of natural transformation in gene acquisition, we analyzed a large collection of genomes of Acinetobacter baumannii (Ab) and Legionella pneumophila (Lp) for which transformation rates were experimentally determined. Natural transformation rates are weakly correlated with genome size. But they are negatively associated with gene turnover in both species. This might result from a negative balance between the transformation's ability to cure the chromosome from mobile genetic elements (MGEs), resulting in gene loss, and its facilitation of gene acquisition. By comparing gene gains by transformation and MGEs, we found that transformation was associated with the acquisition of small sets of genes per event, which were also spread more evenly in the chromosome. We estimated the contribution of natural transformation to gene gains by comparing recombination-driven gene acquisition rates between transformable and non-transformable strains, finding that it facilitated the acquisition of ca. 6.4% (Ab) and 1.1% (Lp) of the novel genes. This moderate contribution of natural transformation to gene acquisition implies that most novel genes are acquired by other means. Yet, 15% of the recently acquired antibiotic resistance genes in A. baumannii may have been acquired by transformation. Hence, natural transformation may drive the acquisition of relatively few novel genes, but these may have a high fitness impact.

RevDate: 2025-08-14

Jiang Y, Shu L, Wen H, et al (2025)

Enhancement of bla IMP-carrying plasmid transfer in Klebsiella pneumoniae by hospital wastewater: a transcriptomic study.

Frontiers in microbiology, 16:1626123.

INTRODUCTION: Klebsiella pneumoniae is a critical ESKAPE pathogen that presents a significant challenge to public health because of its multidrug-resistant strains. This study investigates the impact and mechanisms of hospital wastewater on the horizontal gene transfer of carbapenem resistance genes, particularly bla IMP, in K. pneumoniae.

METHODS: LB broth was prepared using sterile filtered wastewater as the substrate to investigate the impact of wastewater on the transfer of carbapenem-resistant gene bla IMP in K. pneumoniae. The mechanisms of sewage effects on the horizontal transfer of bla IMP were explored by integrating transcriptome sequencing with the detection of extracellular membrane permeability, intracellular reactive oxygen species (ROS), and other test results.

RESULTS: Hospital wastewater significantly enhances the conjugation frequency of plasmids containing bla IMP, showing a two-fold increase in wastewater-based LB broth compared to regular LB broth. In comparison to regular LB broth culture, the wastewater-based LB broth culture group showed significant alterations in the expression of 1,415 genes, with 907 genes upregulated and 508 genes downregulated. Genes related to conjugation transfer systems and the type IV secretion system were significantly upregulated, indicating a potential role in promoting plasmid transfer. Moreover, the treatment of wastewater resulted in elevated intracellular ROS production and increased permeability of bacterial outer membranes, potentially facilitating the spread of antibiotic resistance genes.

DISCUSSION: This research shows that hospital wastewater facilitates the transfer of drug-resistant plasmids containing bla IMP and elucidates its potential mechanisms. A more detailed investigation into these mechanisms may facilitate the prevention of resistance transmission between healthcare and environmental contexts and inform future strategies for managing carbapenem resistance.

RevDate: 2025-08-12

Hamrock FJ, Guest T, Daum MN, et al (2025)

DNA uptake and twitching motility are controlled by the small RNA Arp through repression of pilin translation in Acinetobacter baumannii.

bioRxiv : the preprint server for biology pii:2025.07.19.665661.

UNLABELLED: Acinetobacter baumannii is a major opportunistic pathogen capable of natural transformation, a process driven by type IV pili (T4P) that facilitates horizontal gene transfer and accelerates the spread of antimicrobial resistance. While the transcriptional regulation of T4P is increasingly understood, post-transcriptional mechanisms controlling pilus assembly remain unexplored. Here, we identify and characterise a small RNA, Arp (Acinetobacter repressor of pilin), as a post-transcriptional repressor of T4P-mediated functions in A. baumannii . In a previous Hi-GRIL-seq experiment, we detected specific ligation events between Arp and the ribosome binding site of the pilA mRNA, encoding the major pilin subunit PilA. In-line probing and translational reporter assays revealed that Arp represses pilA translation by sequestering the Shine-Dalgarno sequence and the first 17 codons of the mRNA. Overexpression of Arp significantly impairs DNA uptake and twitching motility, two hallmark T4P-dependent phenotypes. Together, our findings identify a native A. baumannii sRNA that modulates natural competence by targeting pilin synthesis, revealing a new regulatory layer that could be exploited to disrupt horizontal gene transfer in multidrug-resistant strains.

SIGNIFICANCE STATEMENT: Acinetobacter baumannii is a multidrug-resistant WHO #1 priority pathogen that acquires antibiotic resistance genes through natural transformation, a process dependent on type IV pili (T4P). This work reveals Arp, the first native post-transcriptional repressor of natural competence in A. baumannii , uncovering a novel regulatory layer that modulates horizontal gene transfer. The widespread presence of arp in pathogenic Acinetobacter strains suggests that sRNA is an important regulator in those organisms. Furthermore, these findings broaden our understanding of RNA-based regulation in this priority pathogen and open potential avenues for interfering with antibiotic resistance dissemination.

RevDate: 2025-08-14
CmpDate: 2025-08-10

Luo L, Chen X, Liu B, et al (2025)

Strengthen or Weaken: Evolutionary Directions of Cross-Feeding After Formation.

Environmental microbiology reports, 17(4):e70175.

Interactions between species and the evolution of strains are important biotic factors determining the microbial community dynamics, with these two processes being deeply intertwined. Cross-feeding is a prevailing mutualistic interaction in natural microbial communities in which metabolites secreted by one microbe can be utilised by another. Constructing synthetic microbial consortia based on cross-feeding is a promising strategy for bioremediation and bioproduction. But how to improve the performance and the stability of consortia remains a challenge. This review discusses the features of two opposite evolutionary directions of cross-feeding consortia over time, providing insights into the factors affecting the evolutionary process. While coevolving, cross-feeding may strengthen with stronger metabolic coupling, deeper growth dependence, and/or deeper evolutionary dependence; then the consortia become reinforced. Conversely, unsuitable environmental conditions can lead to the direct collapse of the cross-feeding consortia due to metabolic decoupling, partner extinction, or cheater dominance. The loss of the fitness advantage and the constraints on the evolutionary ability can also lead to the weakening of cross-feeding. Cross-feeding partners can affect the evolution of focal strains from different aspects, such as niche space, selective pressure, horizontal gene transfer, and evolutionary rate. Analysing cross-feeding from an evolutionary perspective will advance our understanding of microbial community dynamics and enable rational designs of efficient and stable synthetic microbial consortia.

RevDate: 2025-08-08

Feng X, Li S, Huang D, et al (2025)

Emergence of carbapenem-resistant XDR Salmonella enterica in pediatric patients in South China: a genomic perspective study.

International journal of antimicrobial agents pii:S0924-8579(25)00144-X [Epub ahead of print].

BACKGROUND AND AIM: Carbapenem-resistant Salmonella enterica (CRSE), mostly driven by plasmids, poses a growing public health threat, especially in pediatric populations. This study investigates a cluster of pediatric CRSE infections in pediatric populations, characterizes genomic features of CRSE isolates, assesses global CRSE prevalence, and explores plasmid-mediated horizontal gene transfer.

METHODS: An epidemiological investigation of 18 pediatric CRSE cases was conducted. Genomic analysis included resistome profiling, plasmid typing, and phylogenetic clustering to assess genetic diversity. A global analysis of 530,113 Salmonella genomes identified carbapenemase-carrying isolates. Plasmid transfer experiments between S. enterica and E. coli were performed to evaluate horizontal gene transmission.

RESULTS: Respiratory co-infections (67% of cases, primarily RSV and HPIVs) were associated with severe clinical outcomes. Genomic analysis revealed multiple genetically distinct CRSE clones carrying blaNDM-5, predominantly on IncI-gamma/K1 and IncHI2A plasmids. Plasmid-mediated transfer of carbapenem resistance genes between S. enterica and E. coli was confirmed. Global surveillance identified 228 carbapenemase-positive Salmonella isolates (2000-2023) across 35 genetically diverse populations and 24 countries, demonstrating widespread dissemination.

CONCLUSION: Respiratory co-infections may exacerbate CRSE severity in children, while plasmid circulation drives carbapenem resistance transmission. The high genetic diversity and global distribution of CRSE highlight urgent needs for integrated surveillance, antimicrobial stewardship, and interventions targeting co-infections and environmental reservoirs.

RevDate: 2025-08-19

Bao Y, Ho YW, Shen Z, et al (2025)

Ecological Roles and Shared Microbes Differentiate the Plastisphere from Natural Particle-Associated Microbiomes in Urban Rivers.

Environmental science & technology, 59(32):17298-17309.

The "plastisphere," comprising microbes associated with microplastics (MPs), may have substantial ecological impacts on riverine ecosystems. However, little is known about how the microbiomes associated with anthropogenic MPs compare with those associated with natural particles (NPs) in urban rivers with varying MP pollution levels. We therefore conducted a comparative analysis of the metagenomes associated with MPs and NPs (100-5000 μm) and river water (RW) across 10 urban river systems. Although we found similarities in taxonomic and functional compositions between the microbiomes associated with MPs and NPs, the plastisphere exhibited distinct associations with specialized taxa and life-history strategies. These unique traits enhanced the potential of the plastisphere for complex carbohydrate and plastic degradation, nitrate and nitric oxide reduction, and antibiotic resistance and virulence compared with the NP or RW microbiomes. Furthermore, MPs supported the sharing of unique microbes with the surrounding RW; these shared microbes possessed enhanced horizontal gene transfer capabilities and potentially could disperse traits of the plastisphere into the broader RW microbiomes. This study highlights the distinct ecological roles and shared microbes of the plastisphere, indicating that MP pollution may substantially and uniquely impact the function and health of riverine ecosystems.

RevDate: 2025-08-08

Phimphong T, Hashimoto S, Songwattana P, et al (2025)

Diversity of bradyrhizobial T3SS systems and their roles in symbiosis with peanut (Arachis hypogaea) and Vigna species (V. radiata and V. mungo).

Applied and environmental microbiology [Epub ahead of print].

Symbiosis between Bradyrhizobium strains isolated from Lao People's Democratic Republic (Lao PDR) and intercropped legumes (Arachis hypogaea, Vigna radiata, and V. mungo) was regulated by the type III secretion system (T3SS), which delivers effector proteins (T3Es) into host plant cells to modulate nodulation. To explore this mechanism, we sequenced and analyzed seven Bradyrhizobium genomes, identifying putative T3Es across five T3SS groups (G.1-G.5), which were classified based on the sequence of rhcN, a conserved ATPase gene essential for T3SS function. Phylogenetic analysis of rhcN more closely reflected the evolutionary relationships of nodulation genes than those based on 16S rRNA or whole-genome comparisons, underscoring its symbiotic relevance. Functional assays using rhcN mutants revealed group-specific effects on nodulation; G.1 strains showed neutral effects on A. hypogaea, negative effects on V. radiata, and positive effects on V. mungo. G.2 strains consistently promoted nodulation across all hosts and lacked effectors related to SUMO (small ubiquitin-like modifier) pathways, which have been implicated in host defense regulation. G.3 strains reduced nodulation in A. hypogaea but enhanced it in Vigna species. G.4 strains suppressed nodulation in A. hypogaea, and G.5 strains inhibited nodulation across all tested legumes. These findings highlight the diversity in T3SS organization, effector composition, and symbiotic responses among native Bradyrhizobium strains. The identification of known and uncharacterized effectors suggests roles in host compatibility and specificity. These strains, along with their effector profiles, provide a foundation for future functional studies to better understand T3SS-mediated interactions and support the development of targeted inoculants for legume hosts.IMPORTANCEThis study advances our understanding of legume-Bradyrhizobium symbiosis by examining the genetic organization and evolutionary patterns of T3SS genes. Our findings revealed that T3SS gene evolution does not always align with phylogenies based on 16S rRNA or whole-genome sequences, suggesting that horizontal gene transfer and functional adaptation may shape diversification. The observed variation in T3SS architecture and effector profiles among the five distinct Bradyrhizobium groups was correlated with host-specific nodulation outcomes in A. hypogaea, V. radiata, and V. mungo. We also identified novel candidate genes influencing symbiotic signaling and compatibility. These insights into the diversity and function of T3SS components contribute to a broader understanding of host-microbe communication and may support the development of more targeted and efficient rhizobial inoculants for sustainable legume cultivation and improved biological nitrogen fixation.

RevDate: 2025-08-16

Singh R, Lim CS, Kim H, et al (2025)

Sustainable material platforms for multi-log removal of antibiotic-resistant bacteria and genes from wastewater: A review.

International journal of biological macromolecules, 321(Pt 4):146561.

Antibiotic-resistant bacteria (ARB) and the associated resistance genes (ARGs) are now recognized as emerging contaminants that can disseminate via wastewater streams, posing significant risks to both human and ecosystem health. Conventional physicochemical treatment approaches (e.g., chlorination, ozonation, advanced oxidation processes) typically suppress these contaminants but may also result in the formation of hazardous by-products. This critical review comprehensibly evaluates bio-based and other sustainable materials designed for the removal of ARB and ARGs from aqueous environments. The materials are systematically categorized into (i) biopolymers and their composites (chitosan, alginate, cellulose), (ii) carbon-rich adsorbents and (photo-)catalysts (biochar, activated carbon, graphene), (iii) metal- and semiconductor-based nanomaterials, and (iv) nature-based treatment solutions (constructed wetlands, soil-aquifer treatment, clay sorbents). Observed log-reduction value range from 2 to 7 for ARB with platforms such as zinc oxide/activated-carbon alginate beads, Fe/N-doped biochars, and graphene-supramolecular-porphyrin hybrids demonstrating high multifunctional efficacy. Mechanistic studies reveal that removal involves synergistic adsorption, photodynamic or Fenton-like oxidation, cell-membrane disruption, and inhibition of horizontal gene transfer. This review emphasizes the advancing potential of sustainable material solutions for mitigating antibiotic resistance and highlights the urgent need to develop scalable, environmentally sustainable treatment methods for protecting water resources and public health.

RevDate: 2025-08-14

Vinogradov E, Zou L, Stupak J, et al (2025)

Capsular Polysaccharide of Acinetobacter baumannii MRSN 31196 (a KL1 Variant Strain) and its Degradation by a Recombinant Depolymerase from Bacteriophage vB_AbaP_B5.

Carbohydrate research, 556:109621.

Acinetobacter baumannii MRSN 31196 was assigned as KL1, but has now been reassigned as KL1-v as new polymerase wzy and acetyl transferase (atr25) genes are discovered outside of its gene locus due to horizontal gene transfer. Its capsular polysaccharide (CPS), namely K1v, was isolated by a standard water-phenol extraction and an aqueous base extraction. K1v is degradable by a recombinant phage depolymerase B5 which is known to hydrolyze A. baumannii K9 CPS. The structure of oligosaccharides obtained were determined by NMR and mass spectroscopic analysis. The results showed that the K1v structure is closely related to K1 CPS, with the same sugar composition and linkages except β-QuiNAcNR-(1-3)-GlcNAc in K1v replaced β-QuiNAcNR-(1-4)-GlcNAc in K1, due to an altered Wzy. However, the atr25 gene is likely silenced, or the transferase activity is inhibited, as K1v is not O-acetylated. We also found that the N-acetyl and N-3-hydroxybutyryl (HBu) substitutions (R) in QuiNAcNR has approximately a 1:1 ratio. The mass spectroscopic analysis provided evidence that structural blocks with consecutive QuiNAcNAc or QuiNAcNHBu are present in the polysaccharide. The K1v CPS structure has the following trisaccharide repeating unit.

RevDate: 2025-08-09
CmpDate: 2025-08-09

Yang X, Heng H, Zhang H, et al (2025)

IncFIBK/FIIK conjugative iuc3-carrying virulence plasmids of clinical hypervirulent Klebsiella pneumoniae are multi-drug resistant.

Microbiological research, 300:128288.

Aerobactin encoding loci is the key virulence factor in the virulence plasmid of Klebsiella pneumoniae (Kp). The iuc1 and iuc2 loci are most commonly detected and well-studied, while the iuc3 lineage is less understood. The study investigated comprehensively the iuc3-carrying plasmids in Kp strains providing insights into the diversity, transmission potential and contribution to Kp virulence. The iuc3 was encoded on plasmids ranging from 177,328 bp to 249,880 bp, primarily of the IncFIBK/FIIK5 type, often carrying multi-drug resistance (MDR) regions. Conjugation experiments demonstrated the transferability of iuc3-carrying plasmids, conferring additional resistance to recipient strains. Siderophore production assays indicated that the iuc3 gene cluster significantly enhanced iron acquisition in transconjugants. Analysis of 69,969 Kp isolates from the NCBI Pathogen Detection database identified 872 iuc3-carrying strains across 205 STs and 69 KLs, indicating widespread genetic diversity. These strains were increasingly detected in human clinical samples over time, with additional reservoirs in animals, food, and the environment. The findings underscore the public health threat posed by iuc3-carrying Kp strains, emphasizing the need for surveillance and control measures to prevent the spread of MDR-HvKp clones. This study highlights the complex interplay between plasmid-mediated resistance, virulence, and the potential for horizontal gene transfer in Klebsiella spp.

RevDate: 2025-08-07
CmpDate: 2025-08-07

Hu L, Ye Y, Li Y, et al (2025)

Bacteria-algae synergy in carbon sequestration: Molecular mechanisms, ecological dynamics, and biotechnological innovations.

Biotechnology advances, 83:108655.

Rising atmospheric CO2 levels require innovative strategies to increase carbon sequestration. Bacteria-algae interactions, as pivotal yet underexplored drivers of marine and freshwater carbon sinks, involve multiple mechanisms that amplify CO2 fixation and long-term storage. This review systematically describes the synergistic effects of bacteria-algae consortia spanning both microalgae (e.g., Chlorella vulgaris and Phaeodactylum tricornutum) and macroalgae (e.g., Macrocystis and Laminaria) on carbon sequestration. These effects include (1) molecular-level regulation (e.g., signal transduction via N-acyl-homoserine lactones (AHLs), and horizontal gene transfer), (2) ecological facilitation of recalcitrant dissolved organic carbon (RDOC) formation, and (3) biotechnological applications in wastewater treatment and bioenergy production. We highlight that microbial crosstalk increases algal photosynthesis by 20-40 % and contributes to 18.9 % of kelp-derived RDOC storage. Furthermore, engineered systems integrating algal-bacterial symbiosis achieve greater than 80 % nutrient removal and a 22-35 % increase in CO2 fixation efficiency (compared with axenic algal systems), demonstrating their dual role in climate mitigation and a circular economy. This review is the first to integrate molecular mechanisms (e.g., quorum sensing), ecological carbon transformation processes (e.g., the formation of RDOC), and applications in synthetic biology (e.g., CRISPR-engineered consortia) into a unified framework. Moreover, the novel strategy "microbial interaction network optimization" for enhancing carbon sinks is proposed. However, scalability challenges persist, including light limitations in photobioreactors and the ecological risks of synthetic consortia. By bridging microbial ecology with synthetic biology, this work provides a roadmap for harnessing bacteria-algae synergy to achieve carbon neutrality.

RevDate: 2025-08-14

Tang J, Hu Z, Zhang X, et al (2025)

Evolutionary insights from the pangenome and pigment profiles of Parasynechococcus.

Molecular phylogenetics and evolution, 212:108408.

Parasynechococcus is one of the two essential alongside Prochlorococcus photosynthetic cyanobacteria that contribute primary productivity in the ocean. Despite its global importance its specie delimitation remains controversial. Herein, a pangenome analysis of 39 high-quality genomes was conducted to delineate Parasynechococcus species. Core-gene phylogram revealed the classification of these genomes into 18 well-defined putative genospecies, which was corroborated by ANI index and GTDB classification. Moreover, numerous interspecies and intraspecies HGT events were detected, some of which may be responsible for the inconsistencies between core-gene and pan-gene phylograms. Besides, the profiling of phycobilisome rod region in Parasynechococcus genomes unraveled intriguing diversity of their genomic organization, pigment type and genomic cluster variants. The diversification process was hypothesized to be mediated by the putative mobile elements located in these regions. Moreover, phylogeny incongruence between the genes within phycobilisome rod region and the core genome indicate distinct evolutionary history, which could be ascribed to lateral gene transfer. Conclusively, the results provide insights into the diversity and evolution of Parasynechococcus from the perspective of pangenome and pigment type, facilitating the evolutionary research and exploration of this important taxon.

RevDate: 2025-06-28

Gonzalez Moreno PJ, MK Nishiguchi (2025)

The Competitive Edge: T6SS-Mediated Interference Competition by Vibrionaceae Across Marine Ecological Niches.

Microorganisms, 13(6):.

Interference competition, wherein bacteria actively antagonize and damage their microbial neighbors, is a key ecological strategy governing microbial community structure and composition. To gain a competitive edge, bacteria can deploy a diverse array of antimicrobial weapons-ranging from diffusible toxins to contact-mediated systems in order to eliminate their bacterial rivals. Among Gram-negative bacteria, the type VI secretion system (T6SS) has emerged as a potent and sophisticated contact-dependent mechanism that enables the delivery of toxic cargo into neighboring cells, thereby promoting the colonization and dominance of a bacterial taxon within an ecological niche. In this review, we examine the ecological significance of T6SS-mediated interference competition by members of the Vibrionaceae family across a range of marine habitats that include free-living microbial communities and host-associated niches such as coral and squid symbioses. Additionally, we explore the ecological impact of T6SS-mediated competition in modulating biofilm community structure and promoting horizontal gene transfer within those complex microbial populations. Together, these insights underscore the ecological versatility of the T6SS and emphasize its role in driving antagonistic bacterial interactions and shaping microbial community dynamics within marine ecosystems.

RevDate: 2025-06-28

Lucero J, MK Nishiguchi (2025)

Host-Associated Biofilms: Vibrio fischeri and Other Symbiotic Bacteria Within the Vibrionaceae.

Microorganisms, 13(6):.

Biofilm formation is important for microbial survival, adaptation, and persistence within mutualistic and pathogenic systems in the Vibironaceae. Biofilms offer protection against environmental stressors, immune responses, and antimicrobial treatments by increasing host colonization and resilience. This review examines the mechanisms of biofilm formation in Vibrio species, focusing on quorum sensing, cyclic-di-GMP signaling, and host-specific adaptations that influence biofilm structure and function. We discuss how biofilms differ between mutualistic and pathogenic species based on environmental and host signals. Recent advances in omics technologies such as transcriptomics and metabolomics have enhanced research in biofilm regulation under different conditions. Horizontal gene transfer and phase variation promote the greater fitness of bacterial biofilms due to the diversity of environmental isolates that utilize biofilms to colonize host species. Despite progress, questions remain regarding the long-term effects of biofilm formation and persistence on host physiology and biofilm community dynamics. Research integrating multidisciplinary approaches will help advance our understanding of biofilms and their implications for influencing microbial adaptation, symbiosis, and disease. These findings have applications in biotechnology and medicine, where the genetic manipulation of biofilm regulation can enhance or disrupt microbiome stability and pathogen resistance, eventually leading to targeted therapeutic strategies.

RevDate: 2025-06-24

Li Y, Liu X, Yang J, et al (2025)

Characteristics of intracellular/extracellular antibiotic resistance genes and microbial community in sludge compost under sulfadiazine stress.

Environmental technology [Epub ahead of print].

The accumulation of emerging antibiotics in sewage sludge, which serves as a repository for antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs), is raising growing concern. To accurately assess the environmental risks, it is essential to separately investigate intracellular and extracellular ARGs (iARGs and eARGs) due to their distinct roles in resistance persistence and horizontal gene transfer. However, the impact of sulfadiazine (SDZ) on iARGs and eARGs, and the mechanisms involved in the composting process remain under further investigation. In this study, composts with SDZ concentrations of 5 and 50 mg/kg were constructed, and ARGs, microbial community composition and functional pathways were analyzed. The results showed that the abundance of iARGs varied significantly under SDZ selective pressure, while eARGs showed no significant differences. Specifically, i-erm decreased in the 50SDZ group, likely due to competition for ecological niches. The abundance of ermA, ermB and ermF decreased by approximately 97%, 85%, and 84%, respectively. i-sul increased by 127% to 156% in SDZ-added groups but not dose-dependently. Bacillus, Paracoccus, Pseudomonas, and Caproiciproducens were predominant in the SDZ-added groups. The abundance of potential ARG hosts, such as Bacillus and Paracoccus, increased significantly, with Paracoccus showing 2.3-fold and 1.8-fold higher abundance in the 50SDZ and 5SDZ treatments, respectively, compared to the CK. Functional genes related to the ABC-2 type transport system, signal transduction, and genome maintenance decreased with SDZ application. These findings suggested that the dynamics of ARGs should be continuously monitored during sludge composting and land application of compost products to reduce their environmental risks.

RevDate: 2025-08-12
CmpDate: 2025-08-12

Fang C, Liu H, Chen X, et al (2025)

Thioredoxin-mediated sulfur cycling and biogenic sulfur encapsulation synergistically enhance co-removal of nitrogen, sulfamethoxazole, and resistance genes in constructed wetlands.

Water research, 284:123939.

The interplay between sulfur-driven denitrification and antibiotic resistance genes (ARGs) proliferation remains unresolved in constructed wetlands (CWs), where sulfide accumulation and reactive oxygen species generation paradoxically enhance nitrogen removal while compromising microbial integrity. To resolve this conflict, this study engineered a FeS2@S° composite filler that synergized thioredoxin (Trx)-mediated sulfur cycling and biogenic sulfur (bio-S[0]) encapsulation. Upregulation of trxA/B genes (2.3-fold increase) enabled Trx to convert toxic sulfide into adhesive bio-S[0], exhibiting higher microbial adhesion that shielded functional denitrifiers like Thiomonas (84.03 % viability under SMX stress). Concurrently, sulfur vacancies (SVs) at FeS2 {210} crystal facets generated hydroxyl radicals (•OH) and singlet oxygen ([1]O2) via vacancy-activated pathways, selectively degrading about 73.00 % of extracellular polymeric substance (EPS)-bound ARGs while suppressing horizontal gene transfer (tolC downregulation). The 6:4 FeS2@S[0] system achieved 68.66 % total nitrogen removal and 50.17 % sulfamethoxazole degradation, outperforming conventional substrates by 28.00-39.00 %, alongside a 61.24-67.31 % reduction in ARG abundance. A self-sustaining sulfur cycle recycled about 89.00 % of sulfides into bio-S[0] or FeS2, minimizing H2S emissions (0.045 mg·m[-2]·h[-1]) and maintaining electron flux. By bridging Trx-driven redox homeostasis and bio-S[0]'s physical protection, this work redefines CWs as robust systems capable of simultaneous nitrogen retention, antibiotic degradation, and ARGs suppression, establishing a transformative paradigm for sustainable wastewater treatment.

RevDate: 2025-05-16
CmpDate: 2025-05-16

Gross N, Brodard I, Overesch G, et al (2025)

Genetic basis of β-lactam resistance in Corynebacterium auriscanis and association with otitis externa in dogs and cats.

Veterinary microbiology, 305:110526.

Corynebacterium (C.) auriscanis is an opportunistic pathogen regularly isolated from canine otitis externa, an important condition often hard to treat. We found a surprisingly high prevalence of β-lactam resistant isolates of C. auriscanis (47 %), even though β-lactams are not routinely used for otitis externa treatment in Switzerland. To determine the genetic base of this phenotype, a selection of isolates of C. auriscanis with high and low minimal inhibitory concentration values were subjected to whole genome sequencing. Comparative analysis revealed a gene cassette containing three genes (hdfR encoding a LysR-family transcriptional regulator, blaB encoding a β-lactamase related protein and pbp2c encoding a D,D-transpeptidase) as the likely resistance-encoding determinant in the isolates from otitis externa. This locus had previously been described in C. jeikeium as well as C. diphtheriae and was associated with mobile genetic elements. In our six C. auriscanis isolates the pbp2c locus was always associated with the same IS3 family transposase, an association also found on C. diphtheriae plasmid CP091096, indicating horizontal gene transfer between species. To elucidate the function of the three genes in the pbp2c locus, we constructed plasmids with different combinations of these genes, transformed β-lactam sensitive isolates with the plasmids and tested resistance in the mutants phenotypically. By doing so we confirmed Pbp2c to be the primary factor conferring β-lactam resistance and HdfR and BlaB being important for expression and regulation. Interestingly, resistance to all β-lactams including carbapenems was constitutive in one C. auriscanis transformant while an induction effect was visible for the other transformed C. auriscanis strain, C. glutamicum and C. rouxii as previously described for C. jeikeium. Therefore, testing of β-lactam resistance should be done in combination including induction in Corynebacterium spp.

RevDate: 2025-06-05
CmpDate: 2025-06-02

Lind AL, McDonald NA, Gerrick ER, et al (2025)

Contiguous and complete assemblies of Blastocystis gut microbiome-associated protists reveal evolutionary diversification to host ecology.

Genome research, 35(6):1377-1390.

Blastocystis, an obligate host-associated protist, is the most common microbial eukaryote in the human gut, and is widely distributed across vertebrate hosts. The evolutionary transition of Blastocystis from its free-living stramenopile ancestors to a radiation of host-associated organisms is poorly understood. To explore this, we cultured and sequenced eight strains representing the significant phylogenetic diversity of the genus using long-read, short-read, and Hi-C DNA sequencing, alongside gene annotation and RNA sequencing. Comparative genomic analyses reveal significant variation in gene content and genome structure across Blastocystis. Notably, three strains from herbivorous tortoises, phylogenetically distant from human subtypes, have markedly larger genomes with longer introns and intergenic regions, and retain canonical stop codons absent in the human-associated strains. Despite these genetic differences, all eight isolates exhibit gene losses linked to the reduced cellular complexity of Blastocystis, including losses of cilia and flagella genes, microtubule motor genes, and signal transduction genes. Isolates from herbivorous tortoises contain higher numbers of plant carbohydrate-metabolizing enzymes, suggesting that, like gut bacteria, these protists ferment plant material in the host gut. We find evidence that some of these carbohydrate-metabolizing enzymes were horizontally acquired from bacteria, indicating that horizontal gene transfer is an ongoing process in Blastocystis that has contributed to host-related adaptation. Together, these results highlight substantial genetic and metabolic diversity within the Blastocystis genus, indicating that different lineages of Blastocystis have varied ecological roles in the host gut.

LOAD NEXT 100 CITATIONS

ESP Quick Facts

ESP Origins

In the early 1990's, Robert Robbins was a faculty member at Johns Hopkins, where he directed the informatics core of GDB — the human gene-mapping database of the international human genome project. To share papers with colleagues around the world, he set up a small paper-sharing section on his personal web page. This small project evolved into The Electronic Scholarly Publishing Project.

ESP Support

In 1995, Robbins became the VP/IT of the Fred Hutchinson Cancer Research Center in Seattle, WA. Soon after arriving in Seattle, Robbins secured funding, through the ELSI component of the US Human Genome Project, to create the original ESP.ORG web site, with the formal goal of providing free, world-wide access to the literature of classical genetics.

ESP Rationale

Although the methods of molecular biology can seem almost magical to the uninitiated, the original techniques of classical genetics are readily appreciated by one and all: cross individuals that differ in some inherited trait, collect all of the progeny, score their attributes, and propose mechanisms to explain the patterns of inheritance observed.

ESP Goal

In reading the early works of classical genetics, one is drawn, almost inexorably, into ever more complex models, until molecular explanations begin to seem both necessary and natural. At that point, the tools for understanding genome research are at hand. Assisting readers reach this point was the original goal of The Electronic Scholarly Publishing Project.

ESP Usage

Usage of the site grew rapidly and has remained high. Faculty began to use the site for their assigned readings. Other on-line publishers, ranging from The New York Times to Nature referenced ESP materials in their own publications. Nobel laureates (e.g., Joshua Lederberg) regularly used the site and even wrote to suggest changes and improvements.

ESP Content

When the site began, no journals were making their early content available in digital format. As a result, ESP was obliged to digitize classic literature before it could be made available. For many important papers — such as Mendel's original paper or the first genetic map — ESP had to produce entirely new typeset versions of the works, if they were to be available in a high-quality format.

ESP Help

Early support from the DOE component of the Human Genome Project was critically important for getting the ESP project on a firm foundation. Since that funding ended (nearly 20 years ago), the project has been operated as a purely volunteer effort. Anyone wishing to assist in these efforts should send an email to Robbins.

ESP Plans

With the development of methods for adding typeset side notes to PDF files, the ESP project now plans to add annotated versions of some classical papers to its holdings. We also plan to add new reference and pedagogical material. We have already started providing regularly updated, comprehensive bibliographies to the ESP.ORG site.

cover-pic

SUPPORT ESP: Order from Amazon
The ESP project will earn a commission.

If you thought that the history of life could be organized into a simple tree and that genes only moved from parents to progeny, think again. Recent science has shown that sometimes genes move sideways, skipping the reproductive process, and the tree of life looks more like a tangled bush. David Quammen, a masterful science writer, explains these new findings and more. Read this book and you'll learn about the discovery of the archaea — an entirely different form of life, living right here on this planet, and not noticed until Carl Woese found them, by being among the first to use molecular tools to look at organismal relationships. R. Robbins

Electronic Scholarly Publishing
961 Red Tail Lane
Bellingham, WA 98226

E-mail: RJR8222 @ gmail.com

Papers in Classical Genetics

The ESP began as an effort to share a handful of key papers from the early days of classical genetics. Now the collection has grown to include hundreds of papers, in full-text format.

Digital Books

Along with papers on classical genetics, ESP offers a collection of full-text digital books, including many works by Darwin and even a collection of poetry — Chicago Poems by Carl Sandburg.

Timelines

ESP now offers a large collection of user-selected side-by-side timelines (e.g., all science vs. all other categories, or arts and culture vs. world history), designed to provide a comparative context for appreciating world events.

Biographies

Biographical information about many key scientists (e.g., Walter Sutton).

Selected Bibliographies

Bibliographies on several topics of potential interest to the ESP community are automatically maintained and generated on the ESP site.

ESP Picks from Around the Web (updated 28 JUL 2024 )