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Bibliography on: Archaea

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ESP: PubMed Auto Bibliography 25 Sep 2018 at 01:30 Created: 


In 1977, Carl Woese and George Fox applied molecular techniques to biodiversity and discovered that life on Earth consisted of three, not two (prokaryotes and eukaryotes), major lineages, tracing back nearly to the very origin of life on Earth. The third lineage has come to be known as the Archaea. Organisms now considered Archaea were originally thought to be a kind of prokaryote, but Woese and Fox showed that they were as different from prokaryotes as they were from eukaryotes. To understand life on Earth one must also understand the Archaea .

Created with PubMed® Query: archaea[TITLE] OR archaebacteria[TITLE] NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

RevDate: 2018-09-24

Zaretsky M, Roine E, J Eichler (2018)

Sialic Acid-Like Sugars in Archaea: Legionaminic Acid Biosynthesis in the Halophile Halorubrum sp. PV6.

Frontiers in microbiology, 9:2133.

N-glycosylation is a post-translational modification that occurs in all three domains. In Archaea, however, N-linked glycans present a degree of compositional diversity not observed in either Eukarya or Bacteria. As such, it is surprising that nonulosonic acids (NulOs), nine-carbon sugars that include sialic acids, pseudaminic acids, and legionaminic acids, are routinely detected as components of protein-linked glycans in Eukarya and Bacteria but not in Archaea. In the following, we report that the N-linked glycan attached to the S-layer glycoprotein of the haloarchaea Halorubrum sp. PV6 includes an N-formylated legionaminic acid. Analysis of the Halorubrum sp. PV6 genome led to the identification of sequences predicted to comprise the legionaminic acid biosynthesis pathway. The transcription of pathway genes was confirmed, as was the co-transcription of several of these genes. In addition, the activities of LegI, which catalyzes the condensation of 2,4-di-N-acetyl-6-deoxymannose and phosphoenolpyruvate to generate legionaminic acid, and LegF, which catalyzes the addition of cytidine monophosphate (CMP) to legionaminic acid, both heterologously expressed in Haloferax volcanii, were demonstrated. Further genome analysis predicts that the genes encoding enzymes of the legionaminic acid biosynthetic pathway are clustered together with sequences seemingly encoding components of the N-glycosylation pathway in this organism. In defining the first example of a legionaminic acid biosynthesis pathway in Archaea, the findings reported here expand our insight into archaeal N-glycosylation, an almost universal post-translational modification in this domain of life.

RevDate: 2018-09-22

Maupin-Furlow JA (2018)

Methionine Sulfoxide Reductases of Archaea.

Antioxidants (Basel, Switzerland), 7(10): pii:antiox7100124.

Methionine sulfoxide reductases are found in all domains of life and are important in reversing the oxidative damage of the free and protein forms of methionine, a sulfur containing amino acid particularly sensitive to reactive oxygen species (ROS). Archaea are microbes of a domain of life distinct from bacteria and eukaryotes. Archaea are well known for their ability to withstand harsh environmental conditions that range from habitats of high ROS, such as hypersaline lakes of intense ultraviolet (UV) radiation and desiccation, to hydrothermal vents of low concentrations of dissolved oxygen at high temperature. Recent evidence reveals the methionine sulfoxide reductases of archaea function not only in the reduction of methionine sulfoxide but also in the ubiquitin-like modification of protein targets during oxidative stress, an association that appears evolutionarily conserved in eukaryotes. Here is reviewed methionine sulfoxide reductases and their distribution and function in archaea.

RevDate: 2018-09-20

Eger M, Graz M, Riede S, et al (2018)

Application of MootralTM Reduces Methane Production by Altering the Archaea Community in the Rumen Simulation Technique.

Frontiers in microbiology, 9:2094.

The reduction of methane emissions by ruminants is a highly desirable goal to mitigate greenhouse gas emissions. Various feed additives have already been tested for their ability to decrease methane production; however, practical use is often limited due to negative effects on rumen fermentation or high costs. Organosulphur compounds from garlic (Allium sativum) and flavonoids have been identified as promising plant-derived compounds which are able to reduce methane production. Here, we evaluated the effects of a combination of garlic powder and bitter orange (Citrus aurantium) extracts, Mootral, on ruminal methane production, ruminal fermentation and the community of methanogenic Archaea by using the rumen simulation technique as ex vivo model. The experiment consisted of an equilibration period of 7 days, an experimental period of 8 days and a withdrawal period of 4 days. During the experimental period three fermenters each were either treated as controls (CON), received a low dose of Mootral (LD), a high dose of Mootral (HD), or monensin (MON) as positive control. Application of Mootral strongly reduced the proportion of methane in the fermentation gas and the production rate of methane. Moreover, the experimental mixture induced a dose-dependent increase in the production rate of short chain fatty acids and in the molar proportion of butyrate. Some effects persisted during the withdrawal period. Both, single strand conformation polymorphism and Illumina MiSeq 16S rRNA amplicon sequencing indicated an archaeal community distinct from CON and MON samples in the LD and HD samples. Among archaeal families the percentage of Methanobacteriaceae was reduced during application of both doses of Mootral. Moreover, several significant differences were observed on OTU level among treatment groups and after withdrawal of the additives for LD and HD group. At day 14, 4 OTUs were positively correlated with methane production. In conclusion this mixture of garlic and citrus compounds appears to effectively reduce methane production by alteration of the archaeal community without exhibiting negative side effects on rumen fermentation.

RevDate: 2018-09-17

Ren L, Cai C, Zhang J, et al (2018)

Key environmental factors to variation of ammonia-oxidizing archaea community and potential ammonia oxidation rate during agricultural waste composting.

Bioresource technology, 270:278-285 pii:S0960-8524(18)31295-1 [Epub ahead of print].

In this research, the abundance and structure of AOA amoA gene during agricultural waste composting were determined by quantitative PCR and sequencing techniques, respectively. Pairwise correlations between potential ammonia oxidation (PAO) rate, physicochemical parameters and the AOA abundance were evaluated using Pearson correlation coefficient. Relationships between these parameters, PAO rates and AOA community structure were evaluated by redundancy analysis. Results showed that 22 AOA gene OTUs were divided into the soil/sediment lineage by phylogenetic analyses. Significant positive correlations were obtained between AOA amoA gene abundance and moisture, ammonium, water soluble carbon (WSC) and organic matter (OM), respectively. Redundancy analysis showed OM, pH and nitrate significantly explained the AOA amoA gene structure. Pearson correlation revealed the PAO rate correlated positively to ammonium, AOA amoA gene abundance. These results indicated that AOA communities sense the fluctuations in surrounding environment, and ultimately react and influence the nitrogen transformation during agricultural waste composting.

RevDate: 2018-09-13

Santoro AE, Richter RA, CL Dupont (2018)

Planktonic Marine Archaea.

Annual review of marine science [Epub ahead of print].

Archaea are ubiquitous and abundant members of the marine plankton. Once thought of as rare organisms found in exotic extremes of temperature, pressure, or salinity, archaea are now known in nearly every marine environment. Though frequently referred to collectively, the planktonic archaea actually comprise four major phylogenetic groups, each with its own distinct physiology and ecology. Only one group-the marine Thaumarchaeota-has cultivated representatives, making marine archaea an attractive focus point for the latest developments in cultivation-independent molecular methods. Here, we review the ecology, physiology, and biogeochemical impact of the four archaeal groups using recent insights from cultures and large-scale environmental sequencing studies. We highlight key gaps in our knowledge about the ecological roles of marine archaea in carbon flow and food web interactions. We emphasize the incredible uncultivated diversity within each of the four groups, suggesting there is much more to be done. Expected final online publication date for the Annual Review of Marine Science Volume 11 is January 3, 2019. Please see for revised estimates.

RevDate: 2018-09-12

Patching SG (2018)

Recent developments in nucleobase cation symporter-1 (NCS1) family transport proteins from bacteria, archaea, fungi and plants.

Journal of biosciences, 43(4):797-815.

The nucleobase cation symporter-1 (NCS1) family of secondary active transport proteins comprises over 2500 sequenced members from bacteria, archaea, fungi and plants. NCS1 proteins use a proton or sodium gradient to drive inward cellular transport of purine and pyrimidine nucleobases and nucleosides, hydantoins and related compounds. The structural organization, substrate binding residues and molecular mechanism of NCS1 proteins are defined by crystal structures of sodium-coupled hydantoin transporter, Mhp1. Plant proteins are most closely related to bacterial/archaeal proteins and the distinct Fur-type and Fcy-type fungal proteins and plant proteins originated through independent horizontal transfers from prokaryotes. Analyses of 25 experimentally characterized proteins reveal high substrate specificity in bacterial proteins, distinct non-overlapping specificities in Fur-type and Fcy-type fungal proteins and broad specificity in plant proteins. Possible structural explanations are identified for differences in substrate specificity between bacterial proteins, whilst specificities of other proteins cannot be predicted by simple sequence comparisons. Specificity appears to be species specific and determined by combinations of effects dictated by multiple residues in the major substrate binding site and gating domains. This is an exploratory research review of evolutionary relationships, function and structural organization, molecular mechanism and origins of substrate specificity in NCS1 proteins and avenues of future direction.

RevDate: 2018-09-10

Pan KL, Gao JF, Fan XY, et al (2018)

The more important role of archaea than bacteria in nitrification of wastewater treatment plants in cold season despite their numerical relationships.

Water research, 145:552-561 pii:S0043-1354(18)30696-1 [Epub ahead of print].

Nitrification failure of wastewater treatment plants (WWTPs) in cold season calls into investigations of the functional ammonia-oxidizing microorganisms (AOMs). In this study, we report the abundance of ammonia-oxidizing archaea (AOA), bacteria (AOB) and complete ammonia-oxidizing (comammox) Nitrospira in 23 municipal WWTPs in cold season, and explore the correlations between AOMs abundance and their relative contribution to nitrification. The copy numbers of AOA and AOB amoA gene ranged from 2.42 × 107 to 2.47 × 109 and 5.54 × 106 to 3.31 × 109 copies/g sludge, respectively. The abundance of amoA gene of Candidatus Nitrospira inopinata, an important strain of comammox Nitrospira, was stable with averaged abundance of 8.47 × 106 copies/g sludge. DNA-based stable isotope probing (DNA-SIP) assays were conducted with three typical WWTPs in which the abundance of AOA was lower than, similar to and higher than that of AOB, respectively. The results showed that considerable 13C-assimilation by AOA was detected during active nitrification in all WWTPs, whereas just a much lesser extent of 13C-incorporation by AOB and comammox Nitrospira was found in one WWTP. High-throughput sequencing with 13C-labeled DNA also showed the higher reads abundance of AOA than AOB and comammox Nitrospira. Nitrososphaera viennensis was the dominant active AOA, while Nitrosomonas oligotropha and Nitrosomonas europaea were identified as active AOB. The results obtained suggest that AOA, rather than AOB and comammox Nitrospira, dominate ammonia oxidation in WWTPs in cold season despite the numerical relationships of AOMs.

RevDate: 2018-09-08

Beulig F, Røy H, McGlynn SE, et al (2018)

Cryptic CH4 cycling in the sulfate-methane transition of marine sediments apparently mediated by ANME-1 archaea.

The ISME journal pii:10.1038/s41396-018-0273-z [Epub ahead of print].

Methane in the seabed is mostly oxidized to CO2 with sulfate as the oxidant before it reaches the overlying water column. This microbial oxidation takes place within the sulfate-methane transition (SMT), a sediment horizon where the downward diffusive flux of sulfate encounters an upward flux of methane. Across multiple sites in the Baltic Sea, we identified a systematic discrepancy between the opposing fluxes, such that more sulfate was consumed than expected from the 1:1 stoichiometry of methane oxidation with sulfate. The flux discrepancy was consistent with an oxidation of buried organic matter within the SMT, as corroborated by stable carbon isotope budgets. Detailed radiotracer experiments showed that up to 60% of the organic matter oxidation within the SMT first produced methane, which was concurrently oxidized to CO2 by sulfate reduction. This previously unrecognized "cryptic" methane cycling in the SMT is not discernible from geochemical profiles due to overall net methane consumption. Sedimentary gene pools suggested that nearly all potential methanogens within and beneath the SMT belonged to ANME-1 archaea, which are typically associated with anaerobic methane oxidation. Analysis of a metagenome-assembled genome suggests that predominant ANME-1 do indeed have the enzymatic potential to catalyze both methane production and consumption.

RevDate: 2018-09-06

Ghuneim LJ, Jones DL, Golyshin PN, et al (2018)

Nano-Sized and Filterable Bacteria and Archaea: Biodiversity and Function.

Frontiers in microbiology, 9:1971.

Nano-sized and filterable microorganisms are thought to represent the smallest living organisms on earth and are characterized by their small size (50-400 nm) and their ability to physically pass through <0.45 μm pore size filters. They appear to be ubiquitous in the biosphere and are present at high abundance across a diverse range of habitats including oceans, rivers, soils, and subterranean bedrock. Small-sized organisms are detected by culture-independent and culture-dependent approaches, with most remaining uncultured and uncharacterized at both metabolic and taxonomic levels. Consequently, their significance in ecological roles remain largely unknown. Successful isolation, however, has been achieved for some species (e.g., Nanoarchaeum equitans and "Candidatus Pelagibacter ubique"). In many instances, small-sized organisms exhibit a significant genome reduction and loss of essential metabolic pathways required for a free-living lifestyle, making their survival reliant on other microbial community members. In these cases, the nano-sized prokaryotes can only be co-cultured with their 'hosts.' This paper analyses the recent data on small-sized microorganisms in the context of their taxonomic diversity and potential functions in the environment.

RevDate: 2018-09-03

Ten-Caten F, Vêncio RZN, Lorenzetti APR, et al (2018)

Internal RNAs overlapping coding sequences can drive the production of alternative proteins in archaea.

RNA biology [Epub ahead of print].

Prokaryotic genomes show a high level of information compaction often with different molecules transcribed from the same locus. Although antisense RNAs have been relatively well studied, RNAs in the same strand, internal RNAs (intraRNAs), are still poorly understood. The question of how common is the translation of overlapping reading frames remains open. We address this question in the model archaeon Halobacterium salinarum. In the present work we used differential RNA-seq (dRNA-seq) in H. salinarum NRC-1 to locate intraRNA signals in subsets of internal transcription start sites (iTSS) and establish the open reading frames associated to them (intraORFs). Using C-terminally flagged proteins, we experimentally observed isoforms accurately predicted by intraRNA translation for kef1, acs3 and orc4 genes. We also recovered from the literature and mass spectrometry databases several instances of protein isoforms consistent with intraRNA translation such as the gas visicle protein gene gvpC1. We found evidence for intraRNAs in horizontally transferred genes such as the chaperone dnaK and the aerobic respiration related cydA in both H. salinarum and Escherichia coli. Also, intraRNA translation evidence in H. salinarum, E. coli and yeast of a universal elongation factor (aEF-2, fusA and eEF-2) suggests that this is an ancient phenomenon present in all domains of life.

RevDate: 2018-09-02

Liu Y, Liu J, Yao P, et al (2018)

Distribution patterns of ammonia-oxidizing archaea and bacteria in sediments of the eastern China marginal seas.

Systematic and applied microbiology pii:S0723-2020(18)30032-8 [Epub ahead of print].

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) vary in their contribution to nitrification in different environments. The eastern China marginal seas (ECMS) are featured by complex river runoffs and ocean currents, forming different sediment patches. Here, via quantitative PCR and clone library analysis of the amoA genes, we showed that AOB were more abundant than AOA in ECMS sediments. The abundance, diversity and richness of AOA, but not AOB, were higher in the East China Sea (ECS) than in the Yellow Sea (YS) and Bohai Sea (BS). Nitrosopumilus (AOA) and Nitrosospira (AOB) were predominant lineages, but their abundances varied significantly between ECS, and BS and YS. This was mainly attributed to salinity and dissolved oxygen of the bottom water. The discovery of a high abundance of Nitrosophaera at estuarine sites suggested strong terrigenous influence exerted on the AOA community. In contrast, variations in ocean conditions played more important roles in structuring the AOB community, which was separated by bottom water dissolved oxygen into two groups: the south YS, and the north YS and BS. This study provides a comprehensive insight into the spatial distribution pattern of ammonia-oxidizing prokaryotes in ECMS sediments, laying a foundation for understanding their relative roles in nitrification.

RevDate: 2018-08-30

Borsodi AK, Anda D, Makk J, et al (2018)

Biofilm forming bacteria and archaea in thermal karst springs of Gellért Hill discharge area (Hungary).

Journal of basic microbiology [Epub ahead of print].

The Buda Thermal Karst System (BTKS) is an extensive active hypogenic cave system located beneath the residential area of the Hungarian capital. At the river Danube, several thermal springs discharge forming spring caves. To reveal and compare the morphological structure and prokaryotic diversity of reddish-brown biofilms developed on the carbonate rock surfaces of the springs, scanning electron microscopy (SEM), and molecular cloning were applied. Microbial networks formed by filamentous bacteria and other cells with mineral crystals embedded in extracellular polymeric substances were observed in the SEM images. Biofilms were dominated by prokaryotes belonging to phyla Proteobacteria, Chloroflexi and Nitrospirae (Bacteria) and Thaumarchaeota (Archaea) but their abundance showed differences according to the type of the host rock, geographic distance, and different water exchange. In addition, representatives of phyla Acidobacteria, Actinobacteria, Caldithrix, Cyanobacteria, Firmicutes Gemmatimonadetes, and several candidate divisions of Bacteria as well as Crenarchaeota and Euryarchaeota were detected in sample-dependent higher abundance. The results indicate that thermophilic, anaerobic sulfur-, sulfate-, nitrate-, and iron(III)-reducing chemoorganotrophic as well as sulfur-, ammonia-, and nitrite-oxidizing chemolithotrophic prokaryotes can interact in the studied biofilms adapted to the unique and extreme circumstances (e.g., aphotic and nearly anoxic conditions, oligotrophy, and radionuclide accumulation) in the thermal karst springs.

RevDate: 2018-09-02

Fournier GP, AM Poole (2018)

A Briefly Argued Case That Asgard Archaea Are Part of the Eukaryote Tree.

Frontiers in microbiology, 9:1896.

The recent discovery of the Lokiarchaeota and other members of the Asgard superphylum suggests that closer analysis of the cell biology and evolution of these groups may help shed light on the origin of the eukaryote cell. Asgard lineages often appear in molecular phylogenies as closely related to eukaryotes, and possess "Eukaryote Signature Proteins" coded by genes previously thought to be unique to eukaryotes. This phylogenetic affinity to eukaryotes has been widely interpreted as indicating that Asgard lineages are "eukaryote-like archaea," with eukaryotes evolving from within a paraphyletic Archaea. Guided by the established principles of systematics, we examine the potential implications of the monophyly of Asgard lineages and Eukarya. We show that a helpful parallel case is that of Synapsida, a group that includes modern mammals and their more "reptile-like" ancestors, united by shared derived characters that evolved in their common ancestor. While this group contains extinct members that share many similarities with modern reptiles and their extinct relatives, they are evolutionarily distinct from Sauropsida, the group which includes modern birds, reptiles, and all other amniotes. Similarly, Asgard lineages and eukaryotes are united by shared derived characters to the exclusion of all other groups. Consequently, the Asgard group is not only highly informative for our understanding of eukaryogenesis, but may be better understood as being early diverging members of a broader group including eukaryotes, for which we propose the name "Eukaryomorpha." Significantly, this means that the relationship between Eukarya and Asgard lineages cannot, on its own, resolve the debate over 2 vs. 3 Domains of life; instead, resolving this debate depends upon identifying the root of Archaea with respect to Bacteria.

RevDate: 2018-09-05

Cavazzini D, Grossi G, Levati E, et al (2018)

Author Correction: A family of archaea-like carboxylesterases preferentially expressed in the symbiotic phase of the mycorrhizal fungus Tuber melanosporum.

Scientific reports, 8(1):13173 pii:10.1038/s41598-018-29606-0.

A correction to this article has been published and is linked from the HTML and the PDF versions of this paper. The error has been fixed in the paper.

RevDate: 2018-08-24

Dulmage KA, Darnell CL, Vreugdenhil A, et al (2018)

Copy number variation is associated with gene expression change in archaea.

Microbial genomics [Epub ahead of print].

Genomic instability, although frequently deleterious, is also an important mechanism for microbial adaptation to environmental change. Although widely studied in bacteria, in archaea the effect of genomic instability on organism phenotypes and fitness remains unclear. Here we use DNA segmentation methods to detect and quantify genome-wide copy number variation (CNV) in large compendia of high-throughput datasets in a model archaeal species, Halobacterium salinarum. CNV hotspots were identified throughout the genome. Some hotspots were strongly associated with changes in gene expression, suggesting a mechanism for phenotypic innovation. In contrast, CNV hotspots in other genomic loci left expression unchanged, suggesting buffering of certain phenotypes. The correspondence of CNVs with gene expression was validated with strain- and condition-matched transcriptomics and DNA quantification experiments at specific loci. Significant correlation of CNV hotspot locations with the positions of known insertion sequence (IS) elements suggested a mechanism for generating genomic instability. Given the efficient recombination capabilities in H. salinarum despite stability at the single nucleotide level, these results suggest that genomic plasticity mediated by IS element activity can provide a source of phenotypic innovation in extreme environments.

RevDate: 2018-08-23

Pohlschroder M, SV Albers (2018)

Editorial: Editorial for thematic issue on Archaea.

FEMS microbiology reviews pii:5078070 [Epub ahead of print].

RevDate: 2018-08-17

Hoshino T, F Inagaki (2018)

Abundance and distribution of Archaea in the subseafloor sedimentary biosphere.

The ISME journal pii:10.1038/s41396-018-0253-3 [Epub ahead of print].

Subseafloor sedimentary environments harbor a remarkable number of microorganisms that constitute anaerobic and aerobic microbial ecosystems beneath the ocean margins and open-ocean gyres, respectively. Microbial biomass and diversity richness generally decrease with increasing sediment depth and burial time. However, there has been a long-standing debate over the contribution and distribution of Archaea in the subseafloor sedimentary biosphere. Here we show the global quantification of archaeal and bacterial 16S rRNA genes in 221 sediment core samples obtained from diverse oceanographic settings through scientific ocean drilling using microfluidic digital PCR. We estimated that archaeal cells constitute 37.3% of the total microbial cells (40.0% and 12.8% in the ocean margin and open-ocean sites, respectively), corresponding to 1.1 × 1029 cells on Earth. In addition, the relative abundance of archaeal 16S rRNA genes generally decreased with the depth of water in the overlying sedimentary habitat, suggesting that Archaea may be more sensitive to nutrient quality and quantity supplied from the overlying ocean.

RevDate: 2018-08-16

Grant CR, Wan J, A Komeili (2018)

Organelle Formation in Bacteria and Archaea.

Annual review of cell and developmental biology [Epub ahead of print].

Uncovering the mechanisms that underlie the biogenesis and maintenance of eukaryotic organelles is a vibrant and essential area of biological research. In comparison, little attention has been paid to the process of compartmentalization in bacteria and archaea. This lack of attention is in part due to the common misconception that organelles are a unique evolutionary invention of the "complex" eukaryotic cell and are absent from the "primitive" bacterial and archaeal cells. Comparisons across the tree of life are further complicated by the nebulous criteria used to designate subcellular structures as organelles. Here, with the aid of a unified definition of a membrane-bounded organelle, we present some of the recent findings in the study of lipid-bounded organelles in bacteria and archaea. Expected final online publication date for the Annual Review of Cell and Developmental Biology Volume 34 is October 6, 2018. Please see for revised estimates.

RevDate: 2018-08-14

Albright MBN, Timalsina B, Martiny JBH, et al (2018)

Comparative Genomics of Nitrogen Cycling Pathways in Bacteria and Archaea.

Microbial ecology pii:10.1007/s00248-018-1239-4 [Epub ahead of print].

Despite the explosion of metagenomic sequencing data, using -omics data to predict environmental biogeochemistry remains a challenge. One or a few genes (referred to as marker genes) in a metabolic pathway of interest in meta-omic data are typically used to represent the prevalence of a biogeochemical reaction. This approach often fails to demonstrate a consistent relationship between gene abundance and an ecosystem process rate. One reason this may occur is if a marker gene is not a good representative of a complete pathway. Here, we map the presence of 11 nitrogen (N)-cycling pathways in over 6000 complete bacterial and archaeal genomes using the Integrated Microbial Genomes database. Incomplete N-cycling pathways occurred in 39% of surveyed archaeal and bacterial species revealing a weakness in current marker-gene analyses. Furthermore, we found that most organisms have limited ability to utilize inorganic N in multiple oxidation states. This suggests that inter-organism exchange of inorganic N compounds is common, highlighting the importance of both community composition and spatial structure in determining the extent of recycling versus loss in an ecosystem.

RevDate: 2018-08-17

Gorlas A, Jacquemot P, Guigner JM, et al (2018)

Greigite nanocrystals produced by hyperthermophilic archaea of Thermococcales order.

PloS one, 13(8):e0201549 pii:PONE-D-18-00690.

Interactions between hyperthermophilic archaea and minerals occur in hydrothermal deep-sea vents, one of the most extreme environments for life on Earth. These interactions occur in the internal pores and at surfaces of active hydrothermal chimneys. In this study, we show that, at 85°C, Thermococcales, the predominant hyperthermophilic microorganisms inhabiting hot parts of hydrothermal deep-sea vents, produce greigite nanocrystals (Fe3S4) on extracellular polymeric substances, and that an amorphous iron phosphate acts as a precursor phase. Greigite, although a minor component of chimneys, is a recognized catalyst for CO2 reduction thus implying that Thermococcales may influence the balance of CO2 in hydrothermal ecosystems. We propose that observation of greigite nanocrystals on extracellular polymeric substances could provide a signature of hyperthermophilic life in hydrothermal deep-sea vents.

RevDate: 2018-07-31

Karray F, Ben Abdallah M, Kallel N, et al (2018)

Extracellular hydrolytic enzymes produced by halophilic bacteria and archaea isolated from hypersaline lake.

Molecular biology reports pii:10.1007/s11033-018-4286-5 [Epub ahead of print].

The screening of bacteria and archaea from Chott El Jerid, a hypersaline lake in the south of Tunisia, led to the isolation of 68 extremely halophilic prokaryotes growing in media with 15-25% of salt. Assessment of 68 partial 16S rRNA analyzed by amplified rDNA restriction analysis (ARDRA) revealed 15 different bacterial and archaeal taxonomic groups. Based on ARDRA results, phenotypic and hydrolytic activity tests, 20 archaeal and 6 bacterial isolates were selected for sequencing. The halophilic isolates were identified as members of the genera: Salicola, Bacillus, Halorubrum, Natrinema and Haloterrigena. Most of these isolates are able to produce hydrolytic enzymes such as amylase, protease, lipase, cellulase, xylanase, pectinase and some of them showed combined activities. Natrinema genus is an excellent candidate for lipase production. These results indicated that the extremely halophilic archaea and bacteria from Chott El Jerid are a potential source of hydrolytic enzymes and may possess commercial value.

RevDate: 2018-07-30

Narrowe AB, Spang A, Stairs CW, et al (2018)

Complex evolutionary history of translation Elongation Factor 2 and diphthamide biosynthesis in Archaea and parabasalids.

Genome biology and evolution pii:5060531 [Epub ahead of print].

Diphthamide is a modified histidine residue which is uniquely present in archaeal and eukaryotic elongation factor 2 (EF-2), an essential GTPase responsible for catalyzing the coordinated translocation of tRNA and mRNA through the ribosome. In part due to the role of diphthamide in maintaining translational fidelity, it was previously assumed that diphthamide biosynthesis genes (dph) are conserved across all eukaryotes and archaea. Here, comparative analysis of new and existing genomes reveals that some archaea (i.e., members of the Asgard superphylum, Geoarchaea, and Korarchaeota) and eukaryotes (i.e., parabasalids) lack dph. In addition, while EF-2 was thought to exist as a single copy in archaea, many of these dph-lacking archaeal genomes encode a second EF-2 paralog missing key-residues required for diphthamide modification and for normal translocase function, perhaps suggesting functional divergence linked to loss of diphthamide biosynthesis. Interestingly, some Heimdallarchaeota previously suggested to be most closely related to the eukaryotic ancestor maintain dph genes and a single gene encoding canonical EF-2. Our findings reveal that the ability to produce diphthamide, once thought to be a universal feature in archaea and eukaryotes, has been lost multiple times during evolution, and suggest that anticipated compensatory mechanisms evolved independently.

RevDate: 2018-07-28

Ma M, Du H, Sun T, et al (2018)

Characteristics of archaea and bacteria in rice rhizosphere along a mercury gradient.

The Science of the total environment pii:S0048-9697(18)32665-2 [Epub ahead of print].

Several strains of archaea have the ability to methylate or resist mercury (Hg), and the paddy field is regarded to be conducive to Hg methylation. However, our knowledge of Hg-methylating or Hg-resistant archaea in paddy soils is very limited so far. Therefore, the distribution of archaea and bacteria in the rhizosphere (RS) and bulk soil (BS) of the rice growing in Xiushan Hg-mining area of southwest China was investigated. Bacterial and archaeal 16S rRNA gene amplicon sequencing of the rice rhizosphere along the Hg gradient was conducted. THg concentrations in RS were significantly higher than that in BS at site S1 and S2, while MeHg concentrations in RS was always higher than that in BS, except S6. Bacterial species richness estimates were much higher than that in archaea. The bacterial α-diversity in high-Hg sites was significant higher than that in low-Hg sites based on ACE and Shannon indices. At the genus level, Thiobacillus, Xanthomonas, Defluviicoccus and Candidatus Nitrosoarchaeum were significantly more abundant in the rhizosphere of high-Hg sites, which meant that strains in these genera might play important roles in response to Hg stress. Hg-methylating archaea in the paddy field could potentially be affiliated to strains in Methanosarcina, but further evidence need to be found. The results provide reference to understand archaeal rhizosphere community along an Hg gradient paddy soils.

RevDate: 2018-09-07

Smith-Moore CM, AM Grunden (2018)

Bacteria and archaea as the sources of traits for enhanced plant phenotypes.

Biotechnology advances, 36(7):1900-1916.

Rising global demand for food and population increases are driving the need for improved crop productivity over the next 30 years. Plants have inherent metabolic limitations on productivity such as inefficiencies in carbon fixation and sensitivity to environmental conditions. Bacteria and archaea inhabit some of the most inhospitable environments on the planet and possess unique metabolic pathways and genes to cope with these conditions. Microbial genes involved in carbon fixation, abiotic stress tolerance, and nutrient acquisition have been utilized in plants to enhance plant phenotypes by increasing yield, photosynthesis, and abiotic stress tolerance. Transgenic plants expressing bacterial and archaeal genes will be discussed along with emerging strategies and tools to increase plant growth and yield.

RevDate: 2018-07-29

Kashyap S, Sklute EC, Dyar MD, et al (2018)

Reduction and Morphological Transformation of Synthetic Nanophase Iron Oxide Minerals by Hyperthermophilic Archaea.

Frontiers in microbiology, 9:1550.

Fe(III) (oxyhydr)oxides are electron acceptors for some hyperthermophilic archaea in mildly reducing geothermal environments. However, the kinds of iron oxides that can be used, growth rates, extent of iron reduction, and the morphological changes that occur to minerals are poorly understood. The hyperthermophilic iron-reducing crenarchaea Pyrodictium delaneyi and Pyrobaculum islandicum were grown separately on six different synthetic nanophase Fe(III) (oxyhydr)oxides. For both organisms, growth on ferrihydrite produced the highest growth rates and the largest amounts of Fe(II), although P. delaneyi produced four times more Fe(II) (25 mM) than P. islandicum (6 mM). Both organisms grew on lepidocrocite and akaganéite and produced 2 and 3 mM Fe(II). Modest growth occurred for both organisms on goethite, hematite, and maghemite where ≤1 mM Fe(II) was produced. The diameters of the spherical mineral end-products following P. delaneyi growth increased by 30 nm for ferrihydrite and 50-150 nm for lepidocrocite relative to heated abiotic controls. For akaganéite, spherical particle sizes were the same for P. delaneyi-reacted samples and heated abiotic controls, but the spherical particles were more numerous in the P. delaneyi samples. For P. islandicum, there was no increase in grain size for the mineral end-products following growth on ferrihydrite, lepidocrocite, or akaganéite relative to the heated abiotic controls. High-resolution transmission electron microscopy of lattice fringes and selected-area electron diffraction of the minerals produced by both organisms when grown on ferrihydrite showed that magnetite and/or possibly maghemite were the end-products while the heated abiotic controls only contained ferrihydrite. These results expand the current view of bioavailable Fe(III) (oxyhydr)oxides for reduction by hyperthermophilic archaea when presented as synthetic nanophase minerals. They show that growth and reduction rates are inversely correlated with the iron (oxyhydr)oxide crystallinity and that iron (oxyhydr)oxide mineral transformation takes different forms for these two organisms.

RevDate: 2018-08-24

Heal KR, Qin W, Amin SA, et al (2018)

Accumulation of NO2 -cobalamin in nutrient-stressed ammonia-oxidizing archaea and in the oxygen deficient zone of the eastern tropical North Pacific.

Environmental microbiology reports, 10(4):453-457.

Cobalamin (vitamin B12) is a precious resource in natural systems that is produced by select prokaryotes and required by a broad range of organisms. In this way, the production of cobalamin reinforces numerous microbial interdependencies. Here we report the accumulation of an unusual form of cobalamin, nitrocobalamin (NO2 -cobalamin), in a marine oxygen deficient zone (ODZ), isolates of ammonia-oxidizing archaea (AOA), and an anaerobic ammonium-oxidizing (anammox) bacteria enriched bioreactor. Low oxygen waters were enriched in NO2 -cobalamin, and AOA isolates experiencing ammonia or copper stress produced more NO2 -cobalamin, though there is wide strain-to-strain and batch-to-batch variability. NO2 -cobalamin has no known biochemical role. We hypothesize that AOA and anammox bacteria are a source of marine NO2 -cobalamin in the environment via a reactive nitrogen intermediate. These findings suggest connections between cobalamin forms and nitrogen transformations, physiological stress and ocean deoxygenation.

RevDate: 2018-09-03

Aiewsakun P, Adriaenssens EM, Lavigne R, et al (2018)

Evaluation of the genomic diversity of viruses infecting bacteria, archaea and eukaryotes using a common bioinformatic platform: steps towards a unified taxonomy.

The Journal of general virology, 99(9):1331-1343.

Genome Relationship Applied to Virus Taxonomy (GRAViTy) is a genetics-based tool that computes sequence relatedness between viruses. Composite generalized Jaccard (CGJ) distances combine measures of homology between encoded viral genes and similarities in genome organizational features (gene orders and orientations). This scoring framework effectively recapitulates the current, largely morphology and phenotypic-based, family-level classification of eukaryotic viruses. Eukaryotic virus families typically formed monophyletic groups with consistent CGJ distance cut-off dividing between and within family divergence ranges. In the current study, a parallel analysis of prokaryotic virus families revealed quite different sequence relationships, particularly those of tailed phage families (Siphoviridae, Myoviridae and Podoviridae), where members of the same family were generally far more divergent and often not detectably homologous to each other. Analysis of the 20 currently classified prokaryotic virus families indeed split them into 70 separate clusters of tailed phages genetically equivalent to family-level assignments of eukaryotic viruses. It further divided several bacterial (Sphaerolipoviridae, Tectiviridae) and archaeal (Lipothrixviridae) families. We also found that the subfamily-level groupings of tailed phages were generally more consistent with the family assignments of eukaryotic viruses, and this supports ongoing reclassifications, including Spounavirinae and Vi1virus taxa as new virus families. The current study applied a common benchmark with which to compare taxonomies of eukaryotic and prokaryotic viruses. The findings support the planned shift away from traditional morphology-based classifications of prokaryotic viruses towards a genome-based taxonomy. They demonstrate the feasibility of a unified taxonomy of viruses into which the vast body of metagenomic viral sequences may be consistently assigned.

RevDate: 2018-07-16

van Tran N, Muller L, Ross RL, et al (2018)

Evolutionary insights into Trm112-methyltransferase holoenzymes involved in translation between archaea and eukaryotes.

Nucleic acids research pii:5053166 [Epub ahead of print].

Protein synthesis is a complex and highly coordinated process requiring many different protein factors as well as various types of nucleic acids. All translation machinery components require multiple maturation events to be functional. These include post-transcriptional and post-translational modification steps and methylations are the most frequent among these events. In eukaryotes, Trm112, a small protein (COG2835) conserved in all three domains of life, interacts and activates four methyltransferases (Bud23, Trm9, Trm11 and Mtq2) that target different components of the translation machinery (rRNA, tRNAs, release factors). To clarify the function of Trm112 in archaea, we have characterized functionally and structurally its interaction network using Haloferax volcanii as model system. This led us to unravel that methyltransferases are also privileged Trm112 partners in archaea and that this Trm112 network is much more complex than anticipated from eukaryotic studies. Interestingly, among the identified enzymes, some are functionally orthologous to eukaryotic Trm112 partners, emphasizing again the similarity between eukaryotic and archaeal translation machineries. Other partners display some similarities with bacterial methyltransferases, suggesting that Trm112 is a general partner for methyltransferases in all living organisms.

RevDate: 2018-07-13

Aalto SL, Saarenheimo J, Mikkonen A, et al (2018)

Resistant ammonia-oxidizing archaea endure, but adapting ammonia-oxidizing bacteria thrive in boreal lake sediments receiving nutrient-rich effluents.

Environmental microbiology [Epub ahead of print].

Climate change along with anthropogenic activities change biogeochemical conditions in lake ecosystems, modifying the sediment microbial communities. Wastewater effluents introduce nutrients and organic material but also novel microbes to lake ecosystems, simulating forthcoming increases in catchment loadings. In this work, we first used 16s rRNA gene sequencing to study how the overall sediment microbial community responds to wastewater in six boreal lakes. To examine forthcoming changes in the lake biogeochemistry, we focused on the ammonia-oxidizing archaea (AOA) and bacteria (AOB), and examined their functional and compositional community response to wastewater. Although we found the least diverse and least resistant prokaryotic communities from the most wastewater-influenced sediments, the community changed fast towards the natural composition with the diminishing influence of wastewater. Each lake hosted a unique resistant AOA community, while AOB communities were adapting, responding to environmental conditions as well as receiving new members from WWTPs. In general, AOB dominated in numbers in wastewater-influenced sediments, while the ratio between AOA and AOB increased when moving towards pristine conditions. Our results suggest that although future climate-change-driven increases in nutrient loading and microbial migration might significantly disrupt lake sediment microbiomes, they can promote nitrification through adapting and abundant AOB communities. This article is protected by copyright. All rights reserved.

RevDate: 2018-07-10

Bowers RM, Kyrpides NC, Stepanauskas R, et al (2018)

Corrigendum: Minimum information about a single amplified genome (MISAG) and a metagenome-assembled genome (MIMAG) of bacteria and archaea.

Nature biotechnology, 36(7):660.

RevDate: 2018-07-06

Yip DZ, Veach AM, Yang ZK, et al (2018)

Methanogenic Archaea dominate mature heartwood habitats of Eastern Cottonwood (Populus deltoides).

The New phytologist [Epub ahead of print].

While recent reports demonstrate that the direct emission of methane from living tree trunks may be a significant terrestrial emission source, there has been debate whether tree emissions are due to transport from soils or produced in the wood environment itself. Reports of methanogens from wood of trees were prominent in the literature 40 years ago but have not been revisited with molecular ecology approaches. We examined communities associated with Populus deltoides using rRNA gene sequence analyses and how these vary with tree and wood properties. Our data indicate that wood environments are dominated by anaerobic microbiomes. Methanogens are prominent in heartwood (mean 34% relative abundance) compared to sapwood environments (13%), and dominant operational taxonomic units (OTUs) were classified as the Methanobacterium sp. Members of the Firmicutes phylum comprised 39% of total sequences and were in 42% greater abundance in sapwood over heartwood niches. Tree diameter was the strongest predictor of methanogen abundance, but wood moisture content and pH were also significant predictors of taxon abundance and overall community composition. Unlike microbiomes of the soil, rhizosphere and phyllosphere, wood associated communities are shaped by unique environmental conditions and may be prominent and overlooked sources of methane emissions in temperate forest systems.

RevDate: 2018-07-08

Karimi B, Terrat S, Dequiedt S, et al (2018)

Biogeography of soil bacteria and archaea across France.

Science advances, 4(7):eaat1808 pii:aat1808.

Over the last two decades, a considerable effort has been made to decipher the biogeography of soil microbial communities as a whole, from small to broad scales. In contrast, few studies have focused on the taxonomic groups constituting these communities; thus, our knowledge of their ecological attributes and the drivers determining their composition and distribution is limited. We applied a pyrosequencing approach targeting 16S ribosomal RNA (rRNA) genes in soil DNA to a set of 2173 soil samples from France to reach a comprehensive understanding of the spatial distribution of bacteria and archaea and to identify the ecological processes and environmental drivers involved. Taxonomic assignment of the soil 16S rRNA sequences indicated the presence of 32 bacterial phyla or subphyla and 3 archaeal phyla. Twenty of these 35 phyla were cosmopolitan and abundant, with heterogeneous spatial distributions structured in patches ranging from a 43- to 260-km radius. The hierarchy of the main environmental drivers of phyla distribution was soil pH > land management > soil texture > soil nutrients > climate. At a lower taxonomic level, 47 dominant genera belonging to 12 phyla aggregated 62.1% of the sequences. We also showed that the phylum-level distribution can be determined largely by the distribution of the dominant genus or, alternatively, reflect the combined distribution of all of the phylum members. Together, our study demonstrated that soil bacteria and archaea present highly diverse biogeographical patterns on a nationwide scale and that studies based on intensive and systematic sampling on a wide spatial scale provide a promising contribution for elucidating soil biodiversity determinism.

RevDate: 2018-07-25

Li F, Xie W, Yuan Q, et al (2018)

Genome-scale metabolic model analysis indicates low energy production efficiency in marine ammonia-oxidizing archaea.

AMB Express, 8(1):106 pii:10.1186/s13568-018-0635-y.

Marine ammonia-oxidizing archaea (AOA) play an important role in the global nitrogen cycle by obtaining energy for biomass production from CO2 via oxidation of ammonium. The isolation of Candidatus "Nitrosopumilus maritimus" strain SCM1, which represents the globally distributed AOA in the ocean, provided an opportunity for uncovering the contributions of those AOA to carbon and nitrogen cycles in ocean. Although several ammonia oxidation pathways have been proposed for SCM1, little is known about its ATP production efficiency. Here, based on the published genome of Nitrosopumilus maritimus SCM1, a genome-scale metabolic model named NmrFL413 was reconstructed. Based on the model NmrFL413, the estimated ATP/NH4+ yield (0.149-0.276 ATP/NH4+) is tenfold lower than the calculated theoretical yield of the proposed ammonia oxidation pathways in marine AOA (1.5-1.75 ATP/NH4+), indicating a low energy production efficiency of SCM1. Our model also suggested the minor contribution of marine AOA to carbon cycle comparing with their significant contribution to nitrogen cycle in the ocean.

RevDate: 2018-08-23

Straub CT, Counts JA, Nguyen DMN, et al (2018)

Biotechnology of extremely thermophilic archaea.

FEMS microbiology reviews, 42(5):543-578.

Although the extremely thermophilic archaea (Topt ≥ 70°C) may be the most primitive extant forms of life, they have been studied to a limited extent relative to mesophilic microorganisms. Many of these organisms have unique biochemical and physiological characteristics with important biotechnological implications. These include methanogens that generate methane, fermentative anaerobes that produce hydrogen gas with high efficiency, and acidophiles that can mobilize base, precious and strategic metals from mineral ores. Extremely thermophilic archaea have also been a valuable source of thermoactive, thermostable biocatalysts, but their use as cellular systems has been limited because of the general lack of facile genetics tools. This situation has changed recently, however, thereby providing an important avenue for understanding their metabolic and physiological details and also opening up opportunities for metabolic engineering efforts. Along these lines, extremely thermophilic archaea have recently been engineered to produce a variety of alcohols and industrial chemicals, in some cases incorporating CO2 into the final product. There are barriers and challenges to these organisms reaching their full potential as industrial microorganisms but, if these can be overcome, a new dimension for biotechnology will be forthcoming that strategically exploits biology at high temperatures.

RevDate: 2018-08-22

Staley JT, G Caetano-Anollés (2018)

Archaea-First and the Co-Evolutionary Diversification of Domains of Life.

BioEssays : news and reviews in molecular, cellular and developmental biology, 40(8):e1800036.

The origins and evolution of the Archaea, Bacteria, and Eukarya remain controversial. Phylogenomic-wide studies of molecular features that are evolutionarily conserved, such as protein structural domains, suggest Archaea is the first domain of life to diversify from a stem line of descent. This line embodies the last universal common ancestor of cellular life. Here, we propose that ancestors of Euryarchaeota co-evolved with those of Bacteria prior to the diversification of Eukarya. This co-evolutionary scenario is supported by comparative genomic and phylogenomic analyses of the distributions of fold families of domains in the proteomes of free-living organisms, which show horizontal gene recruitments and informational process homologies. It also benefits from the molecular study of cell physiologies responsible for membrane phospholipids, methanogenesis, methane oxidation, cell division, gas vesicles, and the cell wall. Our theory however challenges popular cell fusion and two-domain of life scenarios derived from sequence analysis, demanding phylogenetic reconciliation. Also see the video abstract here:

RevDate: 2018-06-24

Wu Y, Wu P, Wang B, et al (2018)

Genome-Wide Analysis Reveals Ancestral Lack of Seventeen Different tRNAs and Clade-Specific Loss of tRNA-CNNs in Archaea.

Frontiers in microbiology, 9:1245.

Transfer RNA (tRNA) is a category of RNAs that specifically decode messenger RNAs (mRNAs) into proteins by recognizing a set of 61 codons commonly adopted by different life domains. The composition and abundance of tRNAs play critical roles in shaping codon usage and pairing bias, which subsequently modulate mRNA translation efficiency and accuracy. Over the past few decades, effort has been concentrated on evaluating the specificity and redundancy of different tRNA families. However, the mechanism and processes underlying tRNA evolution have only rarely been investigated. In this study, by surveying tRNA genes in 167 completely sequenced genomes, we systematically investigated the composition and evolution of tRNAs in Archaea from a phylogenetic perspective. Our data revealed that archaeal genomes are compact in both tRNA types and copy number. Generally, no more than 44 different types of tRNA are present in archaeal genomes to decode the 61 canonical codons, and most of them have only one gene copy per genome. Among them, tRNA-Met was significantly overrepresented, with an average of three copies per genome. In contrast, the tRNA-UAU and 16 tRNAs with A-starting anticodons (tRNA-ANNs) were rarely detected in all archaeal genomes. The conspicuous absence of these tRNAs across the archaeal phylogeny suggests they might have not been evolved in the common ancestor of Archaea, rather than have lost independently from different clades. Furthermore, widespread absence of tRNA-CNNs in the Methanococcales and Methanobacteriales genomes indicates convergent loss of these tRNAs in the two clades. This clade-specific tRNA loss may be attributing to the reductive evolution of their genomes. Our data suggest that the current tRNA profiles in Archaea are contributed not only by the ancestral tRNA composition, but also by differential maintenance and loss of redundant tRNAs.

RevDate: 2018-06-19

Höfer K, A Jäschke (2018)

Epitranscriptomics: RNA Modifications in Bacteria and Archaea.

Microbiology spectrum, 6(3):.

The increasingly complex functionality of RNA is contrasted by its simple chemical composition. RNA is generally built from only four different nucleotides (adenine, guanine, cytosine, and uracil). To date, >160 chemical modifications are known to decorate RNA molecules and thereby alter their function or stability. Many RNA modifications are conserved throughout bacteria, archaea, and eukaryotes, while some are unique to each branch of life. Most known modifications occur at internal positions, while there is limited diversity at the termini. The dynamic nature of RNA modifications and newly discovered regulatory functions of some of these RNA modifications gave birth to a new field, now often referred to as "epitranscriptomics." This review highlights the major developments in this field and summarizes detection principles for internal as well as 5'-terminal mRNA modifications in prokaryotes and archaea to investigate their biological significance.

RevDate: 2018-06-18

Ulrich EC, Kamat SS, Hove-Jensen B, et al (2018)

Methylphosphonic Acid Biosynthesis and Catabolism in Pelagic Archaea and Bacteria.

Methods in enzymology, 605:351-426.

Inorganic phosphate is essential for all life forms, yet microbes in marine environments are in near constant deprivation of this important nutrient. Organophosphonic acids can serve as an alternative source of inorganic phosphate if microbes possess the appropriate biochemical pathways that allow cleavage of the stable carbon-phosphorus bond that defines this class of molecule. One prominent source of inorganic phosphate is methylphosphonic acid, which is found as a constituent of marine-dissolved organic matter. The cycle of biosynthesis and catabolism of methylphosphonic acid by marine microbes is the likely source of supersaturating levels of methane in shallow ocean waters. This review provides an overview of the rich biochemistry that has evolved to synthesize methylphosphonic acid and catabolize this molecule into Pi and methane, with an emphasis on the reactions catalyzed by methylphosphonic acid synthase MpnS and the carbon-phosphorus lyase system. The protocols and experiments that are described for MpnS and carbon-phosphorus lyase provide a foundation for studying the structures and mechanisms of these and related enzymes.

RevDate: 2018-07-11

Rodriguez-R LM, Gunturu S, Harvey WT, et al (2018)

The Microbial Genomes Atlas (MiGA) webserver: taxonomic and gene diversity analysis of Archaea and Bacteria at the whole genome level.

Nucleic acids research, 46(W1):W282-W288.

The small subunit ribosomal RNA gene (16S rRNA) has been successfully used to catalogue and study the diversity of prokaryotic species and communities but it offers limited resolution at the species and finer levels, and cannot represent the whole-genome diversity and fluidity. To overcome these limitations, we introduced the Microbial Genomes Atlas (MiGA), a webserver that allows the classification of an unknown query genomic sequence, complete or partial, against all taxonomically classified taxa with available genome sequences, as well as comparisons to other related genomes including uncultivated ones, based on the genome-aggregate Average Nucleotide and Amino Acid Identity (ANI/AAI) concepts. MiGA integrates best practices in sequence quality trimming and assembly and allows input to be raw reads or assemblies from isolate genomes, single-cell sequences, and metagenome-assembled genomes (MAGs). Further, MiGA can take as input hundreds of closely related genomes of the same or closely related species (a so-called 'Clade Project') to assess their gene content diversity and evolutionary relationships, and calculate important clade properties such as the pangenome and core gene sets. Therefore, MiGA is expected to facilitate a range of genome-based taxonomic and diversity studies, and quality assessment across environmental and clinical settings. MiGA is available at

RevDate: 2018-08-28

Feng X, Sun M, Han W, et al (2018)

A transcriptional factor B paralog functions as an activator to DNA damage-responsive expression in archaea.

Nucleic acids research, 46(14):7465.

RevDate: 2018-06-12

Marshall A, Phillips L, Longmore A, et al (2018)

Primer selection influences abundance estimates of ammonia oxidizing archaea in coastal marine sediments.

Marine environmental research pii:S0141-1136(17)30756-0 [Epub ahead of print].

Quantification of the α-subunit of ammonia monooxygenase (amoA) through PCR is an established technique for estimating the abundance of ammonia oxidizing archaea (AOA) in environmental samples. This study quantified AOA with two established primer sets in 1 cm increments from the sediment surface (0-1 cm) to a depth of 10 cm at two locations within Port Phillip Bay (PPB), Australia. Primer choice had a significant effect on within sample estimates of AOA with copy numbers ranging from 102 to 104 copies per ng DNA. Variation in AOA abundance patterns with increasing sediment depth were site and primer specific. Sequence mismatches between the primer binding region of the isolated amoA sequences from PPB and Nitrosopumilus maritimus SCM1 were identified and may explain the high variation identified between primer estimates. Our results highlight the need for testing multiple primer pairs that target different regions of the AOA amoA sequence prior to large-scale marine sediment environmental studies.

RevDate: 2018-06-15

Fu X, Adams Z, JA Maupin-Furlow (2018)

In vitro Analysis of Ubiquitin-like Protein Modification in Archaea.

Bio-protocol, 8(10):.

The ubiquitin-like (Ubl) protein is widely distributed in Archaea and involved in many cellular pathways. A well-established method to reconstitute archaeal Ubl protein conjugation in vitro is important to better understand the process of archaeal Ubl protein modification. This protocol describes the in vitro reconstitution of Ubl protein modification and following analysis of this modification in Haloferax volcanii, a halophilic archaeon serving as the model organism.

RevDate: 2018-08-13

McDougall M, McEleney K, Francisco O, et al (2018)

Reductive power of the archaea right-handed coiled coil nanotube (RHCC-NT) and incorporation of mercury clusters inside protein cages.

Journal of structural biology, 203(3):281-287.

Coiled coils are well described as powerful oligomerization motifs and exhibit a large diversity of functions, including gene regulation, cell division, membrane fusion and drug extrusion. The archaea S-layer originated right-handed coiled coil -RHCC-NT- is characterized by extreme stability and is free of cysteine and histidine moieties. In the current study, we have followed a multidisciplinary approach to investigate the capacity of RHCC-NT to bind a variety of ionic complex metal ions. At the outside of the RHCC-NT, one mercury ion forms an electrostatic interaction with the S-methyl moiety of the single methionine residue present in each coil. We demonstrate that RHCC-NT is reducing and incorporating metallic mercury in the large-sized interior cavities which are lined up along the tetrameric channel.

RevDate: 2018-08-09

Sun M, Feng X, Liu Z, et al (2018)

An Orc1/Cdc6 ortholog functions as a key regulator in the DNA damage response in Archaea.

Nucleic acids research, 46(13):6697-6711.

While bacteria and eukaryotes show distinct mechanisms of DNA damage response (DDR) regulation, investigation of ultraviolet (UV)-responsive expression in a few archaea did not yield any conclusive evidence for an archaeal DDR regulatory network. Nevertheless, expression of Orc1-2, an ortholog of the archaeal origin recognition complex 1/cell division control protein 6 (Orc1/Cdc6) superfamily proteins was strongly activated in Sulfolobus solfataricus and Sulfolobus acidocaldarius upon UV irradiation. Here, a series of experiments were conducted to investigate the possible functions of Orc1-2 in DNA damage repair in Sulfolobus islandicus. Study of DDR in Δorc1-2 revealed that Orc1-2 deficiency abolishes DNA damage-induced differential expression of a large number of genes and the mutant showed hypersensitivity to DNA damage treatment. Reporter gene and DNase I footprinting assays demonstrated that Orc1-2 interacts with a conserved hexanucleotide motif present in several DDR gene promoters and regulates their expression. Manipulation of orc1-2 expression by promoter substitution in this archaeon revealed that a high level of orc1-2 expression is essential but not sufficient to trigger DDR. Together, these results have placed Orc1-2 in the heart of the archaeal DDR regulation, and the resulting Orc1-2-centered regulatory circuit represents the first DDR network identified in Archaea, the third domain of life.

RevDate: 2018-07-08

Mihara T, Koyano H, Hingamp P, et al (2018)

Taxon Richness of "Megaviridae" Exceeds those of Bacteria and Archaea in the Ocean.

Microbes and environments, 33(2):162-171.

Since the discovery of the giant mimivirus, evolutionarily related viruses have been isolated or identified from various environments. Phylogenetic analyses of this group of viruses, tentatively referred to as the family "Megaviridae", suggest that it has an ancient origin that may predate the emergence of major eukaryotic lineages. Environmental genomics has since revealed that Megaviridae represents one of the most abundant and diverse groups of viruses in the ocean. In the present study, we compared the taxon richness and phylogenetic diversity of Megaviridae, Bacteria, and Archaea using DNA-dependent RNA polymerase as a common marker gene. By leveraging existing microbial metagenomic data, we found higher richness and phylogenetic diversity in this single viral family than in the two prokaryotic domains. We also obtained results showing that the evolutionary rate alone cannot account for the observed high diversity of Megaviridae lineages. These results suggest that the Megaviridae family has a deep co-evolutionary history with diverse marine protists since the early "Big-Bang" radiation of the eukaryotic tree of life.

RevDate: 2018-05-25

Ramiro FS, de Lira E, Soares G, et al (2018)

Effects of different periodontal treatments in changing the prevalence and levels of Archaea present in the subgingival biofilm of subjects with periodontitis: A secondary analysis from a randomized controlled clinical trial.

International journal of dental hygiene [Epub ahead of print].

OBJECTIVE: The aim of this randomized double-blind and placebo-controlled study was to assess if periodontal treatment with or without systemic antibiotic would change the mean level of Archaea.

METHODS: Fifty-nine (59) subjects were randomly assigned to receive scaling and root planing (SRP) alone or combined with metronidazole (MTZ; 400 mg/TID) or either with MTZ and amoxicillin (AMX; 500 mg/TID) for 14 days. Clinical and microbiological examinations were performed at baseline and at 6 months post-SRP. Six subgingival plaque samples per subject were analysed for the presence and levels of Archaea using quantitative polymerase chain reaction.

RESULTS: Scaling and root planing alone or combined with MTZ or MTZ + AMX significantly reduced the prevalence of subjects colonized by Archaea at 6 months post-therapy, without significant differences among groups (P > .05). Both therapies led to a statistically significant decrease in the mean percentage of sites colonized by Archaea (P < .05). The MTZ and MTZ + AMX group had a significantly lower mean number of sites colonized by Archaea and lower levels of these micro-organisms at sites with probing depth ≥5 mm at 6 months compared with SRP group (P < .05).

CONCLUSION: Periodontal treatments including adjunctive MTZ or MTZ + AMX are more effective than mechanical treatment alone in reducing the levels and prevalence of sites colonized by Archaea in subjects with chronic periodontitis.

RevDate: 2018-05-25

Teske A (2018)

Aerobic Archaea in iron-rich springs.

Nature microbiology, 3(6):646-647.

RevDate: 2018-08-01

Pedraza-Pérez Y, Cuevas-Vede RA, Canto-Gómez ÁB, et al (2018)

BLAST-XYPlot Viewer: A Tool for Performing BLAST in Whole-Genome Sequenced Bacteria/Archaea and Visualize Whole Results Simultaneously.

G3 (Bethesda, Md.), 8(7):2167-2172 pii:g3.118.200220.

One of the most commonly used tools to compare protein or DNA sequences against databases is BLAST. We introduce a web tool that allows the performance of BLAST-searches of protein/DNA sequences in whole-genome sequenced bacteria/archaea, and displays a large amount of BLAST-results simultaneously. The circular bacterial replicons are projected as horizontal lines with fixed length of 360, representing the degrees of a circle. A coordinate system is created with length of the replicon along the x-axis and the number of replicon used on the y-axis. When a query sequence matches with a gene/protein of a particular replicon, the BLAST-results are depicted as an "x,y" position in a specially adapted plot. This tool allows the visualization of the results from the whole data to a particular gene/protein in real time with low computational resources.

RevDate: 2018-09-07

Nawrocki EP, Jones TA, SR Eddy (2018)

Group I introns are widespread in archaea.

Nucleic acids research, 46(15):7970-7976.

Group I catalytic introns have been found in bacterial, viral, organellar, and some eukaryotic genomes, but not in archaea. All known archaeal introns are bulge-helix-bulge (BHB) introns, with the exception of a few group II introns. It has been proposed that BHB introns arose from extinct group I intron ancestors, much like eukaryotic spliceosomal introns are thought to have descended from group II introns. However, group I introns have little sequence conservation, making them difficult to detect with standard sequence similarity searches. Taking advantage of recent improvements in a computational homology search method that accounts for both conserved sequence and RNA secondary structure, we have identified 39 group I introns in a wide range of archaeal phyla, including examples of group I introns and BHB introns in the same host gene.

RevDate: 2018-06-26

Lui LM, Uzilov AV, Bernick DL, et al (2018)

Methylation guide RNA evolution in archaea: structure, function and genomic organization of 110 C/D box sRNA families across six Pyrobaculum species.

Nucleic acids research, 46(11):5678-5691.

Archaeal homologs of eukaryotic C/D box small nucleolar RNAs (C/D box sRNAs) guide precise 2'-O-methyl modification of ribosomal and transfer RNAs. Although C/D box sRNA genes constitute one of the largest RNA gene families in archaeal thermophiles, most genomes have incomplete sRNA gene annotation because reliable, fully automated detection methods are not available. We expanded and curated a comprehensive gene set across six species of the crenarchaeal genus Pyrobaculum, particularly rich in C/D box sRNA genes. Using high-throughput small RNA sequencing, specialized computational searches and comparative genomics, we analyzed 526 Pyrobaculum C/D box sRNAs, organizing them into 110 families based on synteny and conservation of guide sequences which determine methylation targets. We examined gene duplications and rearrangements, including one family that has expanded in a pattern similar to retrotransposed repetitive elements in eukaryotes. New training data and inclusion of kink-turn secondary structural features enabled creation of an improved search model. Our analyses provide the most comprehensive, dynamic view of C/D box sRNA evolutionary history within a genus, in terms of modification function, feature plasticity, and gene mobility.

RevDate: 2018-05-22

Xu S, Cai C, Guo J, et al (2018)

Different clusters of Candidatus 'Methanoperedens nitroreducens'-like archaea as revealed by high-throughput sequencing with new primers.

Scientific reports, 8(1):7695 pii:10.1038/s41598-018-24974-z.

The newly discovered Candidatus 'Methanoperedens nitroreducens' (M. nitroreducens), mediating nitrate-dependent anaerobic oxidation of methane, is an important microorganism in linking carbon and nitrogen cycles. In order to explore the diversity of M. nitroreducens-like archaea in various environmental niches with advanced high-throughput sequencing, new primers based on alpha subunit of methyl-coenzyme M reductase gene were designed. The PCR results demonstrated that the new primers could effectively detect M. nitroreducens-like archaea from an enrichment culture dominated by M. nitroreducens as well as samples collected from a natural freshwater lake and a full-scale wastewater treatment plant (WWTP). By high-throughput sequencing, more than 30,000 M. nitroreducens-like sequences were obtained. Phylogenetic analysis of these sequences along with published sequences showed that M. nitroreducens-like archaea could be divided into three sub-branches (named as Group A, Group B and Group C in this study). Clear geographical difference was observed, with Group A and Group B dominating samples in Queensland (Australia) and in European ecosystems, respectively. Further quantitative PCR revealed that the M. nitroreducens-like archaea were more abundant in WWTP than the freshwater lake. The study provided a large number of sequences for M. nitroreducens-like archaeal communities, thus expanded our understanding on the ecological diversity of M. nitroreducens-like archaea.

RevDate: 2018-07-15

Sinha N, TA Kral (2018)

Effect of UVC Radiation on Hydrated and Desiccated Cultures of Slightly Halophilic and Non-Halophilic Methanogenic Archaea: Implications for Life on Mars.

Microorganisms, 6(2): pii:microorganisms6020043.

Methanogens have been considered models for life on Mars for many years. In order to survive any exposure at the surface of Mars, methanogens would have to endure Martian UVC radiation. In this research, we irradiated hydrated and desiccated cultures of slightly halophilic Methanococcus maripaludis and non-halophilic Methanobacterium formicicum for various time intervals with UVC (254 nm) radiation. The survivability of the methanogens was determined by measuring methane concentrations in the headspace gas samples of culture tubes after re-inoculation of the methanogens into their growth-supporting media following exposure to UVC radiation. Hydrated M. maripaludis survived 24 h of UVC exposure, while in a desiccated condition they endured for 16 h. M. formicicum also survived UVC radiation for 24 h in a liquid state; however, in a desiccated condition, the survivability of M. formicicum was only 12 h. Some of the components of the growth media could have served as shielding agents that protected cells from damage caused by exposure to ultraviolet radiation. Overall, these results suggest that limited exposure (12⁻24 h) to UVC radiation on the surface of Mars would not necessarily be a limiting factor for the survivability of M. maripaludis and M. formicicum.

RevDate: 2018-06-19

Liu X, Pan J, Liu Y, et al (2018)

Diversity and distribution of Archaea in global estuarine ecosystems.

The Science of the total environment, 637-638:349-358.

Estuarine ecosystem is a unique geographical transitional zone between freshwater and seawater, harboring a wide range of microbial communities including Archaea. Although a large number of Archaea have been detected in such ecosystem, the global patterns in archaeal diversity and distribution are extremely scarce. To bridge this gap, we carried out a comprehensive survey of archaeal communities using ca. 4000 publicly available archaeal 16S rRNA gene sequences (>300 bp) collected from 24 estuaries in different latitude regions. These sequences were divided into 1450 operational taxonomic units (OTUs) at 97% identity, suggesting a high biodiversity that increased gradually from the high- to low-latitude estuaries. Phylogenetic analysis showed that estuarine ecosystem was a large biodiversity pool of Archaea that was mainly composed of 12 phyla. Among them, the predominant groups were Bathyarchaeota, Euryarchaeota and Thaumarchaeota. Interestingly, archaeal distribution demonstrated a geographical differentiation in that Thaumarchaeota was dominated in the low-latitude estuaries, Bathyarchaeota in the mid-latitude estuaries, and Euryarchaeota in the high-latitude estuaries, respectively. Furthermore, the majority of the most abundant 20 OTUs demonstrated an overrepresented or underrepresented distribution pattern in some specific estuaries or latitude regions while a few were evenly distributed throughout the estuaries. This pattern indicates a potential selectivity of geographical distribution. In addition, the analysis of environmental parameters suggested that latitude would be one of the major factors driving the distribution of archaeal communities in estuarine ecosystem. This study profiles a clear framework on the diversity and distribution of Archaea in the global estuarine ecosystem and explores the general environmental factors that influence these patterns. Our findings constitute an important part of the exploration of the global ecology of Archaea.

RevDate: 2018-08-08

Taffner J, Erlacher A, Bragina A, et al (2018)

What Is the Role of Archaea in Plants? New Insights from the Vegetation of Alpine Bogs.

mSphere, 3(3): pii:3/3/e00122-18.

The Archaea represent a significant component of the plant microbiome, whereas their function is still unclear. Different plant species representing the natural vegetation of alpine bogs harbor a substantial archaeal community originating from five phyla, 60 genera, and 334 operational taxonomic units (OTUs). We identified a core archaeome for all bog plants and ecosystem-specific, so far unclassified Archaea In the metagenomic data set, Archaea were found to have the potential to interact with plants by (i) possible plant growth promotion through auxin biosynthesis, (ii) nutrient supply, and (iii) protection against abiotic (especially oxidative and osmotic) stress. The unexpectedly high degree of plant specificity supports plant-archaeon interactions. Moreover, functional signatures of Archaea reveal genetic capacity for the interplay with fungi and an important role in the carbon and nitrogen cycle: e.g., CO2 and N2 fixation. These facts reveal an important, yet unobserved role of the Archaea for plants as well as for the bog ecosystem.IMPORTANCEArchaea are still an underdetected and little-studied part of the plant microbiome. We provide first and novel insights into Archaea as a functional component of the plant microbiome obtained by metagenomic analyses. Archaea were found to have the potential to interact with plants by (i) plant growth promotion through auxin biosynthesis, (ii) nutrient supply, and (iii) protection against abiotic stress.

RevDate: 2018-07-08

White MF, T Allers (2018)

DNA repair in the archaea-an emerging picture.

FEMS microbiology reviews, 42(4):514-526.

There has long been a fascination in the DNA repair pathways of archaea, for two main reasons. Firstly, many archaea inhabit extreme environments where the rate of physical damage to DNA is accelerated. These archaea might reasonably be expected to have particularly robust or novel DNA repair pathways to cope with this. Secondly, the archaea have long been understood to be a lineage distinct from the bacteria, and to share a close relationship with the eukarya, particularly in their information processing systems. Recent discoveries suggest the eukarya arose from within the archaeal domain, and in particular from lineages related to the TACK superphylum and Lokiarchaea. Thus, archaeal DNA repair proteins and pathways can represent a useful model system. This review focuses on recent advances in our understanding of archaeal DNA repair processes including base excision repair, nucleotide excision repair, mismatch repair and double-strand break repair. These advances are discussed in the context of the emerging picture of the evolution and relationship of the three domains of life.

RevDate: 2018-06-26

Rinta-Kanto JM, Pehkonen K, Sinkko H, et al (2018)

Archaea are prominent members of the prokaryotic communities colonizing common forest mushrooms.

Canadian journal of microbiology [Epub ahead of print].

In this study, the abundance and composition of prokaryotic communities associated with the inner tissue of fruiting bodies of Suillus bovinus, Boletus pinophilus, Cantharellus cibarius, Agaricus arvensis, Lycoperdon perlatum, and Piptoporus betulinus were analyzed using culture-independent methods. Our findings indicate that archaea and bacteria colonize the internal tissues of all investigated specimens and that archaea are prominent members of the prokaryotic community. The ratio of archaeal 16S rRNA gene copy numbers to those of bacteria was >1 in the fruiting bodies of four out of six fungal species included in the study. The largest proportion of archaeal 16S rRNA gene sequences belonged to thaumarchaeotal classes Terrestrial group, Miscellaneous Crenarchaeotic Group (MCG), and Thermoplasmata. Bacterial communities showed characteristic compositions in each fungal species. Bacterial classes Gammaproteobacteria, Actinobacteria, Bacilli, and Clostridia were prominent among communities in fruiting body tissues. Bacterial populations in each fungal species had different characteristics. The results of this study imply that fruiting body tissues are an important habitat for abundant and diverse populations of archaea and bacteria.

RevDate: 2018-06-21

Prakash D, Walters KA, Martinie RJ, et al (2018)

Toward a mechanistic and physiological understanding of a ferredoxin:disulfide reductase from the domains Archaea and Bacteria.

The Journal of biological chemistry, 293(24):9198-9209.

Disulfide reductases reduce other proteins and are critically important for cellular redox signaling and homeostasis. Methanosarcina acetivorans is a methane-producing microbe from the domain Archaea that produces a ferredoxin:disulfide reductase (FDR) for which the crystal structure has been reported, yet its biochemical mechanism and physiological substrates are unknown. FDR and the extensively characterized plant-type ferredoxin:thioredoxin reductase (FTR) belong to a distinct class of disulfide reductases that contain a unique active-site [4Fe-4S] cluster. The results reported here support a mechanism for FDR similar to that reported for FTR with notable exceptions. Unlike FTR, FDR contains a rubredoxin [1Fe-0S] center postulated to mediate electron transfer from ferredoxin to the active-site [4Fe-4S] cluster. UV-visible, EPR, and Mössbauer spectroscopic data indicated that two-electron reduction of the active-site disulfide in FDR involves a one-electron-reduced [4Fe-4S]1+ intermediate previously hypothesized for FTR. Our results support a role for an active-site tyrosine in FDR that occupies the equivalent position of an essential histidine in the active site of FTR. Of note, one of seven Trxs encoded in the genome (Trx5) and methanoredoxin, a glutaredoxin-like enzyme from M. acetivorans, were reduced by FDR, advancing the physiological understanding of FDR's role in the redox metabolism of methanoarchaea. Finally, bioinformatics analyses show that FDR homologs are widespread in diverse microbes from the domain Bacteria.

RevDate: 2018-05-08

Mitić NS, Malkov SN, Kovačević JJ, et al (2018)

Structural disorder of plasmid-encoded proteins in Bacteria and Archaea.

BMC bioinformatics, 19(1):158 pii:10.1186/s12859-018-2158-6.

BACKGROUND: In the last decade and a half it has been firmly established that a large number of proteins do not adopt a well-defined (ordered) structure under physiological conditions. Such intrinsically disordered proteins (IDPs) and intrinsically disordered (protein) regions (IDRs) are involved in essential cell processes through two basic mechanisms: the entropic chain mechanism which is responsible for rapid fluctuations among many alternative conformations, and molecular recognition via short recognition elements that bind to other molecules. IDPs possess a high adaptive potential and there is special interest in investigating their involvement in organism evolution.

RESULTS: We analyzed 2554 Bacterial and 139 Archaeal proteomes, with a total of 8,455,194 proteins for disorder content and its implications for adaptation of organisms, using three disorder predictors and three measures. Along with other findings, we revealed that for all three predictors and all three measures (1) Bacteria exhibit significantly more disorder than Archaea; (2) plasmid-encoded proteins contain considerably more IDRs than proteins encoded on chromosomes (or whole genomes) in both prokaryote superkingdoms; (3) plasmid proteins are significantly more disordered than chromosomal proteins only in the group of proteins with no COG category assigned; (4) antitoxin proteins in comparison to other proteins, are the most disordered (almost double) in both Bacterial and Archaeal proteomes; (5) plasmidal proteins are more disordered than chromosomal proteins in Bacterial antitoxins and toxin-unclassified proteins, but have almost the same disorder content in toxin proteins.

CONCLUSION: Our results suggest that while disorder content depends on genome and proteome characteristics, it is more influenced by functional engagements than by gene location (on chromosome or plasmid).

RevDate: 2018-06-01

Meinhardt KA, Stopnisek N, Pannu MW, et al (2018)

Ammonia-oxidizing bacteria are the primary N2 O producers in an ammonia-oxidizing archaea dominated alkaline agricultural soil.

Environmental microbiology [Epub ahead of print].

Most agricultural N2 O emissions are a consequence of microbial transformations of nitrogen (N) fertilizer, and mitigating increases in N2 O emission will depend on identifying microbial sources and variables influencing their activities. Here, using controlled microcosm and field studies, we found that synthetic N addition in any tested amount stimulated the production of N2 O from ammonia-oxidizing bacteria (AOB), but not archaea (AOA), from a bioenergy crop soil. The activities of these two populations were differentiated by N treatments, with abundance and activity of AOB increasing as nitrate and N2 O production increased. Moreover, as N2 O production increased, the isotopic composition of N2 O was consistent with an AOB source. Relative N2 O contributions by both populations were quantified using selective inhibitors and varying N availability. Complementary field analyses confirmed a positive correlation between N2 O flux and AOB abundance with N application. Collectively, our data indicate that AOB are the major N2 O producers, even with low N addition, and that better-metered N application, complemented by selective inhibitors, could reduce projected N2 O emissions from agricultural soils.

RevDate: 2018-07-29

Aouad M, Taib N, Oudart A, et al (2018)

Extreme halophilic archaea derive from two distinct methanogen Class II lineages.

Molecular phylogenetics and evolution, 127:46-54.

Phylogenetic analyses of conserved core genes have disentangled most of the ancient relationships in Archaea. However, some groups remain debated, like the DPANN, a deep-branching super-phylum composed of nanosized archaea with reduced genomes. Among these, the Nanohaloarchaea require high-salt concentrations for growth. Their discovery in 2012 was significant because they represent, together with Halobacteria (a Class belonging to Euryarchaeota), the only two described lineages of extreme halophilic archaea. The phylogenetic position of Nanohaloarchaea is highly debated, being alternatively proposed as the sister-lineage of Halobacteria or a member of the DPANN super-phylum. Pinpointing the phylogenetic position of extreme halophilic archaea is important to improve our knowledge of the deep evolutionary history of Archaea and the molecular adaptive processes and evolutionary paths that allowed their emergence. Using comparative genomic approaches, we identified 258 markers carrying a reliable phylogenetic signal. By combining strategies limiting the impact of biases on phylogenetic inference, we showed that Nanohaloarchaea and Halobacteria represent two independent lines that derived from two distinct but related methanogen Class II lineages. This implies that adaptation to high salinity emerged twice independently in Archaea and indicates that emergence of Nanohaloarchaea within DPANN in previous studies is likely the consequence of a tree reconstruction artifact, challenging the existence of this super-phylum.

RevDate: 2018-08-23

Clouet-d'Orval B, Batista M, Bouvier M, et al (2018)

Insights into RNA-processing pathways and associated RNA-degrading enzymes in Archaea.

FEMS microbiology reviews, 42(5):579-613.

RNA-processing pathways are at the centre of regulation of gene expression. All RNA transcripts undergo multiple maturation steps in addition to covalent chemical modifications to become functional in the cell. This includes destroying unnecessary or defective cellular RNAs. In Archaea, information on mechanisms by which RNA species reach their mature forms and associated RNA-modifying enzymes are still fragmentary. To date, most archaeal actors and pathways have been proposed in light of information gathered from Bacteria and Eukarya. In this context, this review provides a state of the art overview of archaeal endoribonucleases and exoribonucleases that cleave and trim RNA species and also of the key small archaeal proteins that bind RNAs. Furthermore, synthetic up-to-date views of processing and biogenesis pathways of archaeal transfer and ribosomal RNAs as well as of maturation of stable small non-coding RNAs such as CRISPR RNAs, small C/D and H/ACA box guide RNAs, and other emerging classes of small RNAs are described. Finally, prospective post-transcriptional mechanisms to control archaeal messenger RNA quality and quantity are discussed.

RevDate: 2018-06-07

Keshri V, Panda A, Levasseur A, et al (2018)

Phylogenomic Analysis of β-Lactamase in Archaea and Bacteria Enables the Identification of Putative New Members.

Genome biology and evolution, 10(4):1106-1114.

β-lactamases are enzymes which are commonly produced by bacteria and which degrade the β-lactam ring of β-lactam antibiotics, namely penicillins, cephalosporins, carbapenems, and monobactams, and inactivate these antibiotics. We performed a rational and comprehensive investigation of β-lactamases in different biological databases. In this study, we constructed hidden Markov model profiles as well as the ancestral sequence of four classes of β-lactamases (A, B, C, and D), which were used to identify potential β-lactamases from environmental metagenomic (1206), human microbiome metagenomic (6417), human microbiome reference genome (1310), and NCBI's nonredundant databases (44101). Our analysis revealed the existence of putative β-lactamases in the metagenomic databases, which appeared to be similar to the four different molecular classes (A-D). This is the first report on the large-scale phylogenetic diversity of new members of β-lactamases, and our results revealed that metagenomic database dark-matter contains β-lactamase-like antibiotic resistance genes.

RevDate: 2018-08-09

Ausiannikava D, Mitchell L, Marriott H, et al (2018)

Evolution of Genome Architecture in Archaea: Spontaneous Generation of a New Chromosome in Haloferax volcanii.

Molecular biology and evolution, 35(8):1855-1868.

The common ancestry of archaea and eukaryotes is evident in their genome architecture. All eukaryotic and several archaeal genomes consist of multiple chromosomes, each replicated from multiple origins. Three scenarios have been proposed for the evolution of this genome architecture: 1) mutational diversification of a multi-copy chromosome; 2) capture of a new chromosome by horizontal transfer; 3) acquisition of new origins and splitting into two replication-competent chromosomes. We report an example of the third scenario: the multi-origin chromosome of the archaeon Haloferax volcanii has split into two elements via homologous recombination. The newly generated elements are bona fide chromosomes, because each bears "chromosomal" replication origins, rRNA loci, and essential genes. The new chromosomes were stable during routine growth but additional genetic manipulation, which involves selective bottlenecks, provoked further rearrangements. To the best of our knowledge, rearrangement of a naturally evolved prokaryotic genome to generate two new chromosomes has not been described previously.

RevDate: 2018-04-18

Brugère JF, Ben Hania W, Arnal ME, et al (2018)

Archaea: Microbial Candidates in Next-generation Probiotics Development.

Journal of clinical gastroenterology [Epub ahead of print].

Pharmabiotics and probiotics in current use or under development belong to 2 of 3 domains of life, Eukarya (eg, yeasts) and Bacteria (eg, lactobacilli). Archaea constitute a third domain of life, and are currently not used as probiotics, despite several interesting features. This includes the absence of known pathogens in humans, animals, or plants and the existence of some archaea closely associated to humans in various microbiomes. We promote the concept that some specific archaea that naturally thrive in the human gut are potential next-generation probiotics that can be rationally selected on the basis of their metabolic phenotype not being encountered in other human gut microbes, neither Bacteria nor Eukarya. The example of the possible bioremediation of the proatherogenic compound trimethylamine into methane by archaeal microbes is described.

RevDate: 2018-04-22

Alves RJE, Minh BQ, Urich T, et al (2018)

Unifying the global phylogeny and environmental distribution of ammonia-oxidising archaea based on amoA genes.

Nature communications, 9(1):1517 pii:10.1038/s41467-018-03861-1.

Ammonia-oxidising archaea (AOA) are ubiquitous and abundant in nature and play a major role in nitrogen cycling. AOA have been studied intensively based on the amoA gene (encoding ammonia monooxygenase subunit A), making it the most sequenced functional marker gene. Here, based on extensive phylogenetic and meta-data analyses of 33,378 curated archaeal amoA sequences, we define a highly resolved taxonomy and uncover global environmental patterns that challenge many earlier generalisations. Particularly, we show: (i) the global frequency of AOA is extremely uneven, with few clades dominating AOA diversity in most ecosystems; (ii) characterised AOA do not represent most predominant clades in nature, including soils and oceans; (iii) the functional role of the most prevalent environmental AOA clade remains unclear; and (iv) AOA harbour molecular signatures that possibly reflect phenotypic traits. Our work synthesises information from a decade of research and provides the first integrative framework to study AOA in a global context.

RevDate: 2018-04-30

Rother M, V Quitzke (2018)

Selenoprotein synthesis and regulation in Archaea.

Biochimica et biophysica acta pii:S0304-4165(18)30101-6 [Epub ahead of print].

BACKGROUND: The major biological form of selenium is that of the co-translationally inserted amino acid selenocysteine (Sec). In Archaea, the majority of proteins containing Sec, selenoproteins, are involved in methanogenesis. However, the function of this residue is often not known because selenium-independent homologs of the selenoproteins can be employed, sometimes even in one organism.

SCOPE OF REVIEW: This review summarizes current knowledge about the selenoproteins of Archaea, the metabolic pathways where they are involved, and discusses the (potential) function of individual Sec residues. Also, what is known about the "archaeal" way of selenoprotein synthesis, and the regulatory mechanism leading to the replacement of the selenoproteins with selenium-independent homologs, will be presented. Where appropriate, similarities with (and differences to) the respective steps employed in the other two domains, Bacteria and Eukarya, will be emphasized.

MAJOR CONCLUSIONS: Genetic and biochemical studies guided by analysis of genome sequences of Sec-encoding archaea has revealed that the pathway of Sec synthesis in Archaea and Eukarya are principally identical and that Sec insertion in Eukarya probably evolved from an archaeal mechanism employed prior to the separation of the archaeal and eukaryal lines of decent.

GENERAL SIGNIFICANCE: In light of the emerging close phylogenetic relationship of Eukarya and Archaea, archaeal models may be highly valuable tools for unraveling "eukaryotic" principles in molecular and cell biology.

RevDate: 2018-04-22

Wei Z, Wang J, Zhu L, et al (2018)

Toxicity of enrofloxacin, copper and their interactions on soil microbial populations and ammonia-oxidizing archaea and bacteria.

Scientific reports, 8(1):5828 pii:10.1038/s41598-018-24016-8.

Enrofloxacin (EFX) is one of the most frequently used broad-spectrum veterinary drugs, and copper (Cu) is a heavy metal that could easily bind to certain antibiotic molecules. Hence EFX and Cu were chosen as representatives of antibiotics and heavy metals to explore the abundance and variation of soil microbial populations with a plate-counting technique, as well as the copy numbers of amoA gene in ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) by quantitative PCR methods in Argosols samples. Treatments of applied EFX (0.05, 0.20, 0.80 mmol/kg), Cu (1.60 mmol/kg) and combined EFX and Cu (at molar ratios of 1:32,1:8,1:2) exhibited various effects on different soil microorganisms. The toxicity of combined EFX and Cu was more strongly expressed on both soil microbial populations and amoA gene (AOA and AOB) compared to the EFX treatment alone, in most cases, time and dose effects were observed. With respect to the amoA gene, the AOA-amoA gene was more abundant than the AOB-amoA gene, and the ratio ranged from ~8 to ~11. Moreover, the interaction types of EFX and Cu were more likely to be antagonistic (64.29%) than synergistic (35.71%) on soil abundance and function, which may be related to the incubation time and the ratio of EFX to Cu in the soil.

RevDate: 2018-04-15

Gilmour CC, Bullock AL, McBurney A, et al (2018)

Robust Mercury Methylation across Diverse Methanogenic Archaea.

mBio, 9(2): pii:mBio.02403-17.

RevDate: 2018-04-10

Khallef S, Lestini R, Myllykallio H, et al (2018)

Isolation and identification of two extremely halophilic archaea from sebkhas in the Algerian Sahara.

Cellular and molecular biology (Noisy-le-Grand, France), 64(4):83-91.

In Algeria, many salt lakes are to be found spread from southern Tunisia up to the Atlas Mountains in northern Algeria. Oum Eraneb and Ain El beida sebkhas (salt lakes), are located in the Algerian Sahara. The aim of this study was to explore the diversity of the halobacteria in this type of habitats. The physicochemical properties of these shallow saline environments were examined and compared with other hypersaline and marine ecosystems. Both sites were relatively alkaline with a pH around 8.57- 8.74 and rich in salt at 13% and 16% (w/v) salinity for Oum Eraneb and Ain El beida, respectively, with dominant ions of sodium and chloride. The microbial approach revealed the presence of two halophilic archaea, strains JCM13561 and A33T in both explored sebkhas. Growth occurred between 10 and 25% (w/v) NaCl and the isolates grow optimally at 20% (w/v) NaCl. The pH range for growth was 6 to 9.5 with an optimum at pH 7.5 for the first strain and 7 to 9.5 with an optimum pH at 8.5-9 for the second strain. On the basis of 16S rRNA gene sequence analysis, strains JCM13561 and A33T were most closely related to Halorubrum litoreum and Natronorubrum bangense (99% and 96% similarity, respectively).

RevDate: 2018-05-31

McGlynn SE, Chadwick GL, O'Neill A, et al (2018)

Subgroup characteristics of marine methane-oxidizing ANME-2 archaea and their syntrophic partners revealed by integrated multimodal analytical microscopy.

Applied and environmental microbiology pii:AEM.00399-18 [Epub ahead of print].

Phylogenetically diverse environmental ANME archaea and sulfate-reducing bacteria cooperatively catalyze the anaerobic oxidation of methane oxidation (AOM) in multi-celled consortia within methane seep environments. To better understand these cells and their symbiotic associations, we applied a suite of electron microscopy approaches including correlative fluorescence in situhybridization - electron microscopy (FISH-EM), transmission electron microscopy (TEM), and serial block face scanning electron microscopy 3D reconstructions (SBEM). FISH-EM of methane seep derived consortia revealed phylogenetic variability in terms of cell morphology, ultrastructure, and storage granules. Representatives of the ANME-2b clade, but not other ANME-2 groups, contained polyphosphate-like granules, while some bacteria associated with ANME-2a/2c contained two distinct phases of iron mineral chains resembling magnetosomes. 3D segmentation of two ANME-2 consortia types revealed cellular volumes of ANME and their symbiotic partners which were larger than previous estimates based on light microscopy. Phosphorous granule containing ANME (tentatively ANME-2b) were larger than both ANME with no granules and partner bacteria. This cell type was observed with up to 4 granules per cell and the volume of the cell was larger in proportion to the number of granules inside it, but the percent of the cell occupied by these granules did not vary with granule number. These results illuminate distinctions between ANME-2 archaeal lineages and partnering bacterial populations that are apparently unified in their capability of performing anaerobic methane oxidation.Importance Methane oxidation in anaerobic environments can be accomplished by a number of archaeal groups, some of which live in syntrophic relationships with bacteria in structured consortia. Little is known as to the distinguishing characteristics of these groups. Here we applied imaging approaches to better understand the properties of these cells. We found unexpected morphological, structural, and volume variability of these uncultured groups by correlating fluorescence labeling of cells with electron microscopy observables.

RevDate: 2018-04-15

Poehlein A, Heym D, Quitzke V, et al (2018)

Complete Genome Sequence of the Methanococcus maripaludis Type Strain JJ (DSM 2067), a Model for Selenoprotein Synthesis in Archaea.

Genome announcements, 6(14): pii:6/14/e00237-18.

Methanococcus maripaludis type strain JJ (DSM 2067) is an important organism because it serves as a model for primary energy metabolism and hydrogenotrophic methanogenesis and is amenable to genetic manipulation. The complete genome (1.7 Mb) harbors 1,815 predicted protein-encoding genes, including 9 encoding selenoproteins.

RevDate: 2018-08-29

Feng X, Sun M, Han W, et al (2018)

A transcriptional factor B paralog functions as an activator to DNA damage-responsive expression in archaea.

Nucleic acids research, 46(14):7085-7096.

Previously it was shown that UV irradiation induces a strong upregulation of tfb3 coding for a paralog of the archaeal transcriptional factor B (TFB) in Sulfolobus solfataricus, a crenarchaea. To investigate the function of this gene in DNA damage response (DDR), tfb3 was inactivated by gene deletion in Sulfolobus islandicus and the resulting Δtfb3 was more sensitive to DNA damage agents than the original strain. Transcriptome analysis revealed that a large set of genes show TFB3-dependent activation, including genes of the ups operon and ced system. Furthermore, the TFB3 protein was found to be associated with DDR gene promoters and functional dissection of TFB3 showed that the conserved Zn-ribbon and coiled-coil motif are essential for the activation. Together, the results indicated that TFB3 activates the expression of DDR genes by interaction with other transcriptional factors at the promoter regions of DDR genes to facilitate the formation of transcription initiation complex. Strikingly, TFB3 and Ced systems are present in a wide range of crenarchaea, suggesting that the Ced system function as a primary DNA damage repair mechanism in Crenarchaeota. Our findings further suggest that TFB3 and the concurrent TFB1 form a TFB3-dependent DNA damage-responsive circuit with their target genes, which is evolutionarily conserved in the major lineage of Archaea.

RevDate: 2018-06-02

Da Cunha V, Gaia M, Nasir A, et al (2018)

Asgard archaea do not close the debate about the universal tree of life topology.

PLoS genetics, 14(3):e1007215 pii:PGENETICS-D-17-02216.

RevDate: 2018-06-02

Spang A, Eme L, Saw JH, et al (2018)

Asgard archaea are the closest prokaryotic relatives of eukaryotes.

PLoS genetics, 14(3):e1007080 pii:PGENETICS-D-17-01666.

RevDate: 2018-07-23
CmpDate: 2018-07-23

Kiadehi MSH, Amoozegar MA, Asad S, et al (2018)

Exploring the potential of halophilic archaea for the decolorization of azo dyes.

Water science and technology : a journal of the International Association on Water Pollution Research, 77(5-6):1602-1611.

Azo dyes are being extensively used in textile industries, so finding a proper solution to decolorize them is of high importance. In order to find azo dye decolorizing strains among haloarchaea, which are well known for their tolerance to harsh environmental conditions, fifteen haloarchaeal strains were screened. Halogeometricum sp. strain A and Haloferax sp. strain B with the highest decolorization ability (95% and 91% for Remazol black B; both about 60% for Acid blue 161, respectively) were selected for further studies. It was shown that both strains were able to grow and decolorize the dye in a medium containing up to 5 M NaCl, with optimum decolorization activity at 2.5-3.4 M, pH 7, and a wide temperature range between 30 to 45 °C. Moreover, both strains were able to tolerate and decolorize up to 1,000 mg l-1 Remazol black B. Also, they were able to survive in 5,000 mg l-1 of the dye after 20 days' incubation. Glucose and yeast extract were found to be the best carbon and nitrogen sources in the decolorization medium for both strains. This is the first report studying decolorization of azo dyes using halophilic archaea.

RevDate: 2018-05-30
CmpDate: 2018-05-30

Pillot G, Frouin E, Pasero E, et al (2018)

Specific enrichment of hyperthermophilic electroactive Archaea from deep-sea hydrothermal vent on electrically conductive support.

Bioresource technology, 259:304-311.

While more and more investigations are done to study hyperthermophilic exoelectrogenic communities from environments, none have been performed yet on deep-sea hydrothermal vent. Samples of black smoker chimney from Rainbow site on the Atlantic mid-oceanic ridge have been harvested for enriching exoelectrogens in microbial electrolysis cells under hyperthermophilic (80 °C) condition. Two enrichments were performed in a BioElectrochemical System specially designed: one from direct inoculation of crushed chimney and the other one from inoculation of a pre-cultivation on iron (III) oxide. In both experiments, a current production was observed from 2.4 A/m2 to 5.8 A/m2 with a set anode potential of -0.110 V vs Ag/AgCl. Taxonomic affiliation of the exoelectrogen communities obtained on the electrode exhibited a specific enrichment of Archaea belonging to Thermococcales and Archeoglobales orders, even when both inocula were dominated by Bacteria.

RevDate: 2018-03-09

Anonymous (2018)

Extreme Excitement about Archaea.

Cell, 172(6):1153-1154.

RevDate: 2018-03-28

Gelsinger DR, J DiRuggiero (2018)

The Non-Coding Regulatory RNA Revolution in Archaea.

Genes, 9(3): pii:genes9030141.

Small non-coding RNAs (sRNAs) are ubiquitously found in the three domains of life playing large-scale roles in gene regulation, transposable element silencing and defense against foreign elements. While a substantial body of experimental work has been done to uncover function of sRNAs in Bacteria and Eukarya, the functional roles of sRNAs in Archaea are still poorly understood. Recently, high throughput studies using RNA-sequencing revealed that sRNAs are broadly expressed in the Archaea, comprising thousands of transcripts within the transcriptome during non-challenged and stressed conditions. Antisense sRNAs, which overlap a portion of a gene on the opposite strand (cis-acting), are the most abundantly expressed non-coding RNAs and they can be classified based on their binding patterns to mRNAs (3' untranslated region (UTR), 5' UTR, CDS-binding). These antisense sRNAs target many genes and pathways, suggesting extensive roles in gene regulation. Intergenic sRNAs are less abundantly expressed and their targets are difficult to find because of a lack of complete overlap between sRNAs and target mRNAs (trans-acting). While many sRNAs have been validated experimentally, a regulatory role has only been reported for very few of them. Further work is needed to elucidate sRNA-RNA binding mechanisms, the molecular determinants of sRNA-mediated regulation, whether protein components are involved and how sRNAs integrate with complex regulatory networks.

RevDate: 2018-03-24

Burns JA, Pittis AA, E Kim (2018)

Publisher Correction: Gene-based predictive models of trophic modes suggest Asgard archaea are not phagocytotic.

Nature ecology & evolution, 2(4):751.

In the version of this Article originally published, question marks appeared in Table 1; they should have been tick marks. This has now been corrected in all versions of the Article.

RevDate: 2018-03-04

Liu J, Yu Z, Yao Q, et al (2018)

Ammonia-Oxidizing Archaea Show More Distinct Biogeographic Distribution Patterns than Ammonia-Oxidizing Bacteria across the Black Soil Zone of Northeast China.

Frontiers in microbiology, 9:171.

Black soils (Mollisols) of northeast China are highly productive and agriculturally important for food production. Ammonia-oxidizing microbes play an important role in N cycling in the black soils. However, the information related to the composition and distribution of ammonia-oxidizing microbes in the black soils has not yet been addressed. In this study, we used the amoA gene to quantify the abundance and community composition of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) across the black soil zone. The amoA abundance of AOA was remarkably larger than that of AOB, with ratios of AOA/AOB in the range from 3.1 to 91.0 across all soil samples. The abundance of AOA amoA was positively correlated with total soil C content (p < 0.001) but not with soil pH (p > 0.05). In contrast, the abundance of AOB amoA positively correlated with soil pH (p = 0.009) but not with total soil C. Alpha diversity of AOA did not correlate with any soil parameter, however, alpha diversity of AOB was affected by multiple soil factors, such as soil pH, total P, N, and C, available K content, and soil water content. Canonical correspondence analysis indicated that the AOA community was mainly affected by the sampling latitude, followed by soil pH, total P and C; while the AOB community was mainly determined by soil pH, as well as total P, C and N, water content, and sampling latitude, which highlighted that the AOA community was more geographically distributed in the black soil zone of northeast China than AOB community. In addition, the pairwise analyses showed that the potential nitrification rate (PNR) was not correlated with alpha diversity but weakly positively with the abundance of the AOA community (p = 0.048), whereas PNR significantly correlated positively with the richness (p = 0.003), diversity (p = 0.001) and abundance (p < 0.001) of the AOB community, which suggested that AOB community might make a greater contribution to nitrification than AOA community in the black soils when ammonium is readily available.

RevDate: 2018-03-01
CmpDate: 2018-03-01

Ma W, Sun J, Li Y, et al (2018)

17α-Ethynylestradiol biodegradation in different river-based groundwater recharge modes with reclaimed water and degradation-associated community structure of bacteria and archaea.

Journal of environmental sciences (China), 64:51-61.

This study investigated 17α-ethynylestradiol (EE2) biodegradation process and primary metabolic pathways associated with community structures of microorganism during groundwater recharge using reclaimed water. The attenuation rate is 1.58 times higher in wetting and drying alternative recharge (WDAR) than in continual recharge (CR). The primary biotransformation pathways of EE2 in WDAR system began with the oxidation of C-17 on ring D to form a ketone group, and D-ring was subsequently hydroxylated and cleaved. In the CR system, the metabolic pathway changed from the oxidation of C-17 on ring D to hydroxylation of C-4 on ring A, and ring A or B subsequently cleaved; this transition was related to DO, and the microbial community structure. Four hundred fifty four pyrosequencing of 16s rRNA genes indicated that the bacterial communities in the upper layer of the WDAR system were more diverse than those found in the bottom layer of the CR system; this result was reversed for archaea. Unweighted UniFrac and taxonomic analyses were conducted to relate the change in bacterial community structure to the metabolic pathway. Microorganism community diversity and structure were related to the concentrations of dissolved oxygen, EE2 and its intermediates in the system. Five known bacterial classes and one known archaeal class, five major bacterial genera and one major archaeal genus might be involved in EE2 degradation. The findings of this study provide an understanding of EE2 biodegradation in groundwater recharge areas under different recharging modes and can facilitate the prediction of the fate of EE2 in underground aquifers.

RevDate: 2018-03-07

Oger PM (2018)

Complete Genome Sequences of 11 Type Species from the Thermococcus Genus of Hyperthermophilic and Piezophilic Archaea.

Genome announcements, 6(8): pii:6/8/e00037-18.

We report here the genome sequences of the type strains of the species Thermococcus barossii, T. celer, T. chitonophagus, T. gorgonarius, T. pacificus, T. peptonophilus, T. profundus, T. radiotolerans, T. siculi, and T. thioreducens, as well as the prototype of a possible type strain of a novel Thermococcus species, strain P6.

RevDate: 2018-04-23

Abdul Halim MF, Rodriguez R, Stoltzfus JD, et al (2018)

Conserved residues are critical for Haloferax volcanii archaeosortase catalytic activity: Implications for convergent evolution of the catalytic mechanisms of non-homologous sortases from archaea and bacteria.

Molecular microbiology, 108(3):276-287.

Proper protein anchoring is key to the biogenesis of prokaryotic cell surfaces, dynamic, resilient structures that play crucial roles in various cell processes. A novel surface protein anchoring mechanism in Haloferax volcanii depends upon the peptidase archaeosortase A (ArtA) processing C-termini of substrates containing C-terminal tripartite structures and anchoring mature substrates to the cell membrane via intercalation of lipid-modified C-terminal amino acid residues. While this membrane protein lacks clear homology to soluble sortase transpeptidases of Gram-positive bacteria, which also process C-termini of substrates whose C-terminal tripartite structures resemble those of ArtA substrates, archaeosortases do contain conserved cysteine, arginine and arginine/histidine/asparagine residues, reminiscent of His-Cys-Arg residues of sortase catalytic sites. The study presented here shows that ArtAWT -GFP expressed in trans complements ΔartA growth and motility phenotypes, while alanine substitution mutants, Cys173 (C173A), Arg214 (R214A) or Arg253 (R253A), and the serine substitution mutant for Cys173 (C173S), fail to complement these phenotypes. Consistent with sortase active site replacement mutants, ArtAC173A -GFP, ArtAC173S -GFP and ArtAR214A -GFP cannot process substrates, while replacement of the third residue, ArtAR253A -GFP retains some processing activity. These findings support the view that similarities between certain aspects of the structures and functions of the sortases and archaeosortases are the result of convergent evolution.

RevDate: 2018-03-24

Burns JA, Pittis AA, E Kim (2018)

Gene-based predictive models of trophic modes suggest Asgard archaea are not phagocytotic.

Nature ecology & evolution, 2(4):697-704.

With the current explosion of genomic data, there is a greater need to draw inference on phenotypic information based on DNA sequence alone. We considered complete genomes from 35 diverse eukaryotic lineages, and discovered sets of proteins predictive of trophic mode, including a set of 485 proteins that are enriched among phagocytotic eukaryotes (organisms that internalize large particles). Our model is also predictive of other aspects of trophic mode, including photosynthesis and the ability to synthesize a set of organic compounds needed for growth (prototrophy for those molecules). We applied our model to the Asgard archaea, a group of uncultured microorganisms that show close affinities to eukaryotes, to test whether the organisms are capable of phagocytosis, a phenotypic trait often considered a prerequisite for mitochondrial acquisition. Our analyses suggest that members of the Asgard archaea-despite having some eukaryote-specific protein families not found in other prokaryotes-do not use phagocytosis. Moreover, our data suggest that the process of phagocytosis arose from a combination of both archaeal and bacterial components, but also required additional eukaryote-specific innovations.

RevDate: 2018-03-09

Yan L, Wang G, Ai S, et al (2018)

Abundance of ammonia-oxidizing bacteria and archaea under different ventilation strategies during cattle manure composting.

Journal of environmental management, 212:375-383.

Composting of cattle manure was conducted under four ventilation strategies, i.e., no-aeration (A-00), continuous aeration (B-44), non-aeration for 14 d and then aeration for 42 d (C-04), aeration for 14 d and then no-aeration for 42 d (D-40). Physicochemical parameters and potential ammonia oxidation (PAO) indicated that continuous and intermittent ventilation provide favourable conditions for ammonia-oxidizing bacteria (AOB) and archaea (AOA) to oxidize ammonia. Quantitative PCR (qPCR) analysis showed AOB amoA gene abundance of all treatments on every sampling day ranged from 2.25 × 105 to 2.76 × 109copies/g, was significantly lower than that of archaeal amoA gene from 2.71 × 108 to 9.05 × 1011copies/g. There was also a significantly positive relationship between PAO rates and AOB (r2 ≥ 0.066, p < 0.05) and AOA (r2 ≥ 0.300, p < 0.05) abundance. These data suggested that ammonia oxidation is driven by both AOA and AOB in cattle manure composting.

RevDate: 2018-08-02

Araujo ASF, Mendes LW, Bezerra WM, et al (2018)

Archaea diversity in vegetation gradients from the Brazilian Cerrado.

Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology], 49(3):522-528.

We used 16S rRNA sequencing to assess the archaeal communities across a gradient of Cerrado. The archaeal communities differed across the gradient. Crenarcheota was the most abundant phyla, with Nitrosphaerales and NRPJ as the predominant classes. Euryachaeota was also found across the Cerrado gradient, including the classes Metanocellales and Methanomassiliicoccaceae.

RevDate: 2018-08-16
CmpDate: 2018-08-16

Menasria T, Aguilera M, Hocine H, et al (2018)

Diversity and bioprospecting of extremely halophilic archaea isolated from Algerian arid and semi-arid wetland ecosystems for halophilic-active hydrolytic enzymes.

Microbiological research, 207:289-298.

The diversity of haloarchaea associated with different dry salt lakes in northeastern Algeria was investigated together with their potential of hydrolytic enzyme production. A total of 68 aerobic halophilic archaea were isolated from saline sediments. Based on the 16S rRNA gene sequencing, the isolates were assigned to seven phylotypes within the class Halobacteria, namely Haloarcula, Halococcus, Haloferax, Halogeometricum, Haloterrigena, Natrialba, and Natrinema. The results showed that Haloferax group was found to be dominant in all samples (30 isolates) (44%) with high diversity, followed by Halococcus spp. (13%) (9 isolates). All phylotypes are extreme halophiles and thermotolerant with the ability to grow at temperatures up to 48 °C. In addition, the screening for extracellular halophilic enzymes showed that 89.7% of the isolates were able to produce at least two types of the screened enzymes. The strains producing esterase, gelatinase, inulinase, cellulase and protease activities were the most diverse functional group. These data showed an abundant and diverse haloarchaeal community, detected in Algerian wetland ecosystems, presenting a promising source of molecules with important biotechnological applications.

RevDate: 2018-02-21

He H, Zhen Y, Mi T, et al (2018)

Ammonia-Oxidizing Archaea and Bacteria Differentially Contribute to Ammonia Oxidation in Sediments from Adjacent Waters of Rushan Bay, China.

Frontiers in microbiology, 9:116.

Ammonia oxidation plays a significant role in the nitrogen cycle in marine sediments. Ammonia-oxidizing archaea (AOA) and bacteria (AOB) are the key contributors to ammonia oxidation, and their relative contribution to this process is one of the most important issues related to the nitrogen cycle in the ocean. In this study, the differential contributions of AOA and AOB to ammonia oxidation in surface sediments from adjacent waters of Rushan Bay were studied based on the ammonia monooxygenase (amoA) gene. Molecular biology techniques were used to analyze ammonia oxidizers' community characteristics, and potential nitrification incubation was applied to understand the ammonia oxidizers' community activity. The objective was to determine the community structure and activity of AOA and AOB in surface sediments from adjacent waters of Rushan Bay and to discuss the different contributions of AOA and AOB to ammonia oxidation during summer and winter seasons in the studied area. Pyrosequencing analysis revealed that the diversity of AOA was higher than that of AOB. The majority of AOA and AOB clustered into Nitrosopumilus and Nitrosospira, respectively, indicating that the Nitrosopumilus group and Nitrosospira groups may be more adaptable in studied sediments. The AOA community was closely correlated to temperature, salinity and ammonium concentration, whereas the AOB community showed a stronger correlation with temperature, chlorophyll-a content (chla) and nitrite concentration. qPCR results showed that both the abundance and the transcript abundance of AOA was consistently greater than that of AOB. AOA and AOB differentially contributed to ammonia oxidation in different seasons. AOB occupied the dominant position in mediating ammonia oxidation during summer, while AOA might play a dominant role in ammonia oxidation during winter.

RevDate: 2018-03-19

Řezanka T, Kolouchová I, Gharwalová L, et al (2018)

Lipidomic Analysis: From Archaea to Mammals.

Lipids, 53(1):5-25.

Lipids are among the most important organic compounds found in all living cells, from primitive archaebacteria to flowering plants or mammalian cells. They form part of cell walls and constitute cell storage material. Their biosynthesis and metabolism play key roles in faraway topics such as biofuel production (third-generation biofuels produced by microorganisms, e.g. algae) and human diseases such as adrenoleukodystrophy, Zellweger syndrome, or Refsum disease. Current lipidomic analysis requires fast and accurate processing of samples and especially their characterization. Because the number of possible lipids and, more specifically, molecular species of lipids is of the order of hundreds to thousands, it is necessary to process huge amounts of data in a short time. There are two basic approaches to lipidomic analysis: shotgun and liquid chromatography-mass spectometry. Both methods have their pros and cons. This review deals with lipidomics not according to the type of ionization or the lipid classes analyzed but according to the types of samples (organisms) under study. Thus, it is divided into lipidomic analysis of archaebacteria, bacteria, yeast, fungi, algae, plants, and animals.

RevDate: 2018-07-10

Huang Z, Jiang Y, Song X, et al (2018)

Ammonia-oxidizing bacteria and archaea within biofilters of a commercial recirculating marine aquaculture system.

AMB Express, 8(1):17 pii:10.1186/s13568-018-0551-1.

While biofilters are widely used to metabolize ammonia and other wastes in marine recirculating aquaculture systems, the ammonia-oxidizing bacterial and archaeal communities have not been characterized across a diversity of production systems. Using a metagenomics approach, we characterized the ammonia-oxidizing microbiological community of biofilters in a commercial recirculating marine aquaculture system producing hybrid grouper (Epinephelus lanceolatus × E. fuscoguttatus). Cloning and sequencing of the amoA gene showed that nitrifying bacteria included Nitrosomonas europea, N. stercoris, N. cryotolerans, N. eutropha, N. estuarii, eight strains of N. marina, and 15 strains not associated with described species. Nitrifying archaea included eight strains of Nitrosopumilus maritimus, N. koreensis, N. piranensis, N. adriaticus, undescribed congeners, and other undescribed archaea. The species composition of the bacterial and especially the archaeal communities was beyond that yet reported for aquaculture biofilters. While ammonia flux through the respective communities has yet to be estimated, the diverse environmental adaptations of the bacterial and archaeal communities suggest resilience of function under a range of environmental conditions.

RevDate: 2018-02-09

Bowers RM, Kyrpides NC, Stepanauskas R, et al (2018)

Corrigendum: Minimum information about a single amplified genome (MISAG) and a metagenome-assembled genome (MIMAG) of bacteria and archaea.

Nature biotechnology, 36(2):196.

RevDate: 2018-07-05
CmpDate: 2018-07-05

Brzezińska-Błaszczyk E, Pawłowska E, Płoszaj T, et al (2018)

Presence of archaea and selected bacteria in infected root canal systems.

Canadian journal of microbiology, 64(5):317-326.

Infections of the root canal have polymicrobial etiology. The main group of microflora in the infected pulp is bacteria. There is limited data that archaea may be present in infected pulp tissue. The aim of this study was to check the prevalence of archaea in necrotic root canal samples obtained from patients with primary or post-treatment infection. The prevalence of selected bacteria species (Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Synergistes sp.) in necrotic samples was evaluated as well. Sixty-four samples from root canal were collected for DNA and RNA extraction. A PCR assay based on the 16S rRNA gene was used to determine the presence of archaea and selected bacteria. Of the 64 samples, 6 were analyzed by semiquantitative reverse transcription PCR to estimate expression profiles of 16S rRNA, and another 9 were selected for direct sequencing. Archaea were detected in 48.4% samples. Statistical analysis indicated a negative association in coexistence between archaea and Treponema denticola (P < 0.05; Pearson's χ2 test). The main representative of the Archaea domain found in infected pulp tissue was Methanobrevibacter oralis. Archaea 16S rRNA gene expression was significantly lower than Synergistes sp., Porphyromonas gingivalis, and Tannerella forsythia (P < 0.05; Student's t test). Thus, it can be hypothesized that archaea may participate in the endodontic microbial community.

RevDate: 2018-02-14

Gonzalez-Martinez A, Sihvonen M, Muñoz-Palazon B, et al (2018)

Microbial ecology of full-scale wastewater treatment systems in the Polar Arctic Circle: Archaea, Bacteria and Fungi.

Scientific reports, 8(1):2208 pii:10.1038/s41598-018-20633-5.

Seven full-scale biological wastewater treatment systems located in the Polar Arctic Circle region in Finland were investigated to determine their Archaea, Bacteria and Fungi community structure, and their relationship with the operational conditions of the bioreactors by the means of quantitative PCR, massive parallel sequencing and multivariate redundancy analysis. The results showed dominance of Archaea and Bacteria members in the bioreactors. The activated sludge systems showed strong selection of Bacteria but not for Archaea and Fungi, as suggested by diversity analyses. Core OTUs in influent and bioreactors were classified as Methanobrevibacter, Methanosarcina, Terrestrial Group Thaumarchaeota and unclassified Euryarchaeota member for Archaea; Trichococcus, Leptotrichiaceae and Comamonadaceae family, and Methylorosula for Bacteria and Trichosporonaceae family for Fungi. All influents shared core OTUs in all domains, but in bioreactors this did not occur for Bacteria. Oligotype structure of core OTUs showed several ubiquitous Fungi oligotypes as dominant in sewage and bioreactors. Multivariate redundancy analyses showed that the majority of core OTUs were related to organic matter and nutrients removal. Also, there was evidence of competition among Archaea and Fungi core OTUs, while all Bacteria OTUs were positively correlated among them. The results obtained highlighted interesting features of extremely cold temperature bioreactors.

RevDate: 2018-02-28

Seyler LM, McGuinness LR, Gilbert JA, et al (2018)

Discerning autotrophy, mixotrophy and heterotrophy in marine TACK archaea from the North Atlantic.

FEMS microbiology ecology, 94(3):.

DNA stable isotope probing (SIP) was used to track the uptake of organic and inorganic carbon sources for TACK archaea (Thaumarchaeota/Aigarchaeota/Crenarchaeota/Korarchaeota) on a cruise of opportunity in the North Atlantic. Due to water limitations, duplicate samples from the deep photic (60-115 m), the mesopelagic zones (local oxygen minimum; 215-835 m) and the bathypelagic zone (2085-2835 m) were amended with various combinations of 12C- or 13C-acetate/urea/bicarbonate to assess cellular carbon acquisition. The SIP results indicated the majority of TACK archaeal operational taxonomic units (OTUs) incorporated 13C from acetate and/or urea into newly synthesized DNA within 48 h. A small fraction (16%) of the OTUs, often representing the most dominant members of the archaeal community, were able to incorporate bicarbonate in addition to organic substrates. Only two TACK archaeal OTUs were found to incorporate bicarbonate but not urea or acetate. These results further demonstrate the utility of SIP to elucidate the metabolic capability of mesothermal archaea in distinct oceanic settings and suggest that TACK archaea play a role in organic carbon recycling in the mid-depth to deep ocean.

RevDate: 2018-02-08

Li M, Wei G, Shi W, et al (2018)

Distinct distribution patterns of ammonia-oxidizing archaea and bacteria in sediment and water column of the Yellow River estuary.

Scientific reports, 8(1):1584 pii:10.1038/s41598-018-20044-6.

Ammonia oxidation is a critical process of estuarine nitrogen cycling involving ammonia-oxidizing archaea (AOA) and bacteria (AOB). However, the distribution patterns of ammonia-oxidizing microorganisms (AOMs) between different habitats in the same area remain unclear. The present study investigated the AOMs' abundance and community compositions in both sediment and water habitats of the Yellow River estuary. Quantitative PCR (qPCR) revealed that AOA showed significant higher abundance than AOB both in sediment and water samples. AOA and AOB abundance distribution trends were consistent in sediment but distinct in water along the sampling sites. Clone library-based analyses showed that AOA sequences were affiliated with Nitrososphaera, Nitrosopumilus and Nitrosotalea clusters. Generally, Nitrososphaera was predominant in sediment, while Nitrosopumilus and Nitrosotalea dominated in water column. AOB sequences were classified into genera Nitrosospira and Nitrosomonas, and Nitrosospira dominated in both habitats. Principal coordinate analysis (PCoA) also indicated AOA community structures exhibited significant differences between two habitats, while AOB were not. Ammonium and carbon contents were the potential key factors to influence AOMs' abundance and compositions in sediment, while no measured variables were determined to have major influences on communities in water habitat. These findings increase the understanding of the AOMs' distribution patterns in estuarine ecosystems.

RevDate: 2018-07-10
CmpDate: 2018-07-10

Bell SD (2017)

Initiation of DNA Replication in the Archaea.

Advances in experimental medicine and biology, 1042:99-115.

Organisms within the archaeal domain of life possess a simplified version of the eukaryotic DNA replication machinery. While some archaea possess a bacterial-like mode of DNA replication with single origins of replication per chromosome, the majority of species characterized to date possess chromosomes with multiple replication origins. Genetic, structural, and biochemical studies have revealed the nature of archaeal origin specification. Recent work has begun to shed light on the mechanisms of replication initiation in these organisms.

RevDate: 2018-02-03

Singh A, AK Singh (2018)

Isolation, characterization and exploring biotechnological potential of halophilic archaea from salterns of western India.

3 Biotech, 8(1):45.

Thirteen halophilic archaea were isolated from Kandla and Bhayander salt pans. These isolates were grouped into three different genera Halobacterium, Haloferax and Haloarcula based on morphological and biochemical characterization, polar lipid analysis, Amplified 16S rDNA restriction analysis (ARDRA) and 16S rDNA sequence analysis. Biochemical characterization suggested the ability of isolates to produce protease, amylase and poly-hydroxybutyrate (PHB) indicating their biotechnological potential. The isolates were further screened for the amount of extracellular protease produced. Halobacterium sp. SP1(1) showed significant protease production compared to other isolates. Protease producing ability of the isolate was influenced by several factors such as NaCl concentration, type of protein source, metal ions and surfactants, and presence of amino acid supplements in the production medium. Soybean flour, FeCl3 and dicotylsulfosuccinate were found to increase protease production by 2.36, 1.54 and 1.26 folds, respectively compared to production in basal medium. Effect of organic solvents used in paints (n-decane, n-undecane and n-dodecane) was also investigated on protease production by the isolate. Protease production by Halobacterium sp. SP1(1) was enhanced by 1.2 folds in presence of n-decane compared to control. Furthermore, the ability of isolate to hydrolyse fish protein was investigated using three different edible fishes (Pomfret, Flat fish and Seer fish) as sole protein source. Pomfret was found to be a good protein source for protease production by the isolate. These results revealed that Halobacterium sp. SP1(1) may have potential for paint-based antifouling coating preparations and fish sauce preparation by virtue of its extracellular protease.

RevDate: 2018-09-05
CmpDate: 2018-09-05

Oren A, Hirschberg J, Mann V, et al (2018)

Effects of nicotine on the biosynthesis of carotenoids in halophilic Archaea (class Halobacteria): an HPLC and Raman spectroscopy study.

Extremophiles : life under extreme conditions, 22(3):359-366.

Nicotine has a profound influence on the carotenoid metabolism in halophilic Archaea of the class Halobacteria. In a study of Halobacterium salinarum, Haloarcula marismortui and Halorubrum sodomense, using different analytical techniques to monitor the production of different carotenoids as a function of the presence of nicotine, we showed that the formation of α-bacterioruberin was inhibited in all. In Hbt. salinarum, addition of nicotine led to a significant change in the color of the culture due to the accumulation of lycopene, in addition to the formation of bisanhydrobacterioruberin which does not differ in color from α-bacterioruberin. Very little or no lycopene was formed in Har. marismortui and in Hrr. sodomense; instead bisanhydrobacterioruberin was the only major carotenoid found in nicotine-amended cultures. The findings are discussed in the framework of the recently elucidated biochemical pathway for the formation of the different carotenoid pigments encountered in the Halobacteria.

RevDate: 2018-02-15
CmpDate: 2018-02-15

Bader M, Müller K, Foerstendorf H, et al (2018)

Comparative analysis of uranium bioassociation with halophilic bacteria and archaea.

PloS one, 13(1):e0190953 pii:PONE-D-17-18886.

Rock salt represents a potential host rock formation for the final disposal of radioactive waste. The interactions between indigenous microorganisms and radionuclides, e.g. uranium, need to be investigated to better predict the influence of microorganisms on the safety assessment of the repository. Hence, the association process of uranium with two microorganisms isolated from rock salt was comparatively studied. Brachybacterium sp. G1, which was isolated from the German salt dome Gorleben, and Halobacterium noricense DSM15987T, were selected as examples of a moderately halophilic bacterium and an extremely halophilic archaeon, respectively. The microorganisms exhibited completely different association behaviors with uranium. While a pure biosorption process took place with Brachybacterium sp. G1 cells, a multistage association process occurred with the archaeon. In addition to batch experiments, in situ attenuated total reflection Fourier-transform infrared spectroscopy was applied to characterize the U(VI) interaction process. Biosorption was identified as the dominating process for Brachybacterium sp. G1 with this method. Carboxylic functionalities are the dominant interacting groups for the bacterium, whereas phosphoryl groups are also involved in U(VI) association by the archaeon H. noricense.

RevDate: 2018-03-18

Srithep P, Pornkulwat P, T Limpiyakorn (2018)

Contribution of ammonia-oxidizing archaea and ammonia-oxidizing bacteria to ammonia oxidation in two nitrifying reactors.

Environmental science and pollution research international, 25(9):8676-8687.

In this study, two laboratory nitrifying reactors (NRI and NRII), which were seeded by sludge from different sources and operated under different operating conditions, were found to possess distinct dominant ammonia-oxidizing microorganisms. Ammonia-oxidizing archaeal (AOA) amoA genes outnumbered ammonia-oxidizing bacterial (AOB) amoA genes in reactor NRI, while only AOB amoA genes were detectable in reactor NRII. The AOA amoA gene sequences retrieved from NRI were characterized within the Nitrososphaera sister cluster of the group 1.1b Thaumarchaeota. Two inhibitors for ammonia oxidation, allylthiourea (ATU) and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO), were applied individually and as a mixture to observe the ammonia-oxidizing activity of both microorganisms in the reactors' sludge. The results indicated that AOA and AOB jointly oxidized ammonia in NRI, while AOB played the main role in ammonia oxidation in NRII. DNA-stable isotope probing with labeled 13C-HCO3- was performed on NRI sludge. Incorporation of 13C into AOA and AOB implied that both microorganisms may perform autotrophy during ammonia oxidation. Taken together, the results from this study provide direct evidence demonstrating the contribution of AOA and AOB to ammonia oxidation in the nitrifying reactors.


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.

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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).


ESP now offers a much improved and expanded collection of timelines, designed to give the user choice over subject matter and dates.


Biographical information about many key scientists.

Selected Bibliographies

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

ESP Picks from Around the Web (updated 07 JUL 2018 )