Viewport Size Code:
Login | Create New Account
picture

  MENU

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

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

icon

Bibliography Options Menu

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

Bibliography on: Wolbachia

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

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

ESP: PubMed Auto Bibliography 27 Mar 2024 at 01:58 Created: 

Wolbachia

WIKIPEDIA: Wolbachia is a genus of bacteria which "infects" (usually as intracellular symbionts) arthropod species, including a high proportion of insects, as well as some nematodes. It is one of the world's most common parasitic microbes and is possibly the most common reproductive parasite in the biosphere. Its interactions with its hosts are often complex, and in some cases have evolved to be mutualistic rather than parasitic. Some host species cannot reproduce, or even survive, without Wolbachia infection. One study concluded that more than 16% of neotropical insect species carry bacteria of this genus, and as many as 25 to 70 percent of all insect species are estimated to be potential hosts. Wolbachia also harbor a temperate bacteriophage called WO. Comparative sequence analyses of bacteriophage WO offer some of the most compelling examples of large-scale horizontal gene transfer between Wolbachia coinfections in the same host. It is the first bacteriophage implicated in frequent lateral transfer between the genomes of bacterial endosymbionts. Gene transfer by bacteriophages could drive significant evolutionary change in the genomes of intracellular bacteria that were previously considered highly stable or prone to loss of genes overtime. Outside of insects, Wolbachia infects a variety of isopod species, spiders, mites, and many species of filarial nematodes (a type of parasitic worm), including those causing onchocerciasis ("River Blindness") and elephantiasis in humans as well as heartworms in dogs. Not only are these disease-causing filarial worms infected with Wolbachia, but Wolbachia seem to play an inordinate role in these diseases. A large part of the pathogenicity of filarial nematodes is due to host immune response toward their Wolbachia. Elimination of Wolbachia from filarial nematodes generally results in either death or sterility of the nematode.

Created with PubMed® Query: wolbachia NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

-->

RevDate: 2024-03-26

Fricke LC, ARI Lindsey (2024)

Identification of parthenogenesis-inducing effector proteins in Wolbachia.

Genome biology and evolution pii:7635173 [Epub ahead of print].

Bacteria in the genus Wolbachia have evolved numerous strategies to manipulate arthropod sex, including the conversion of would-be male offspring to asexually reproducing females. This so-called "parthenogenesis-induction" phenotype can be found in a number of Wolbachia strains that infect arthropods with haplodiploid sex determination systems, including parasitoid wasps. Despite the discovery of microbe-mediated parthenogenesis more than 30 years ago, the underlying genetic mechanisms have remained elusive. We used a suite of genomic, computational, and molecular tools to identify and characterize two proteins that are uniquely found in parthenogenesis-inducing Wolbachia and have strong signatures of host-associated bacterial effector proteins. These putative parthenogenesis-inducing proteins have structural homology to eukaryotic protein domains including nucleoporins, the key insect sex-determining factor Transformer, and a eukaryotic-like serine-threonine kinase with leucine rich repeats. Furthermore, these proteins significantly impact eukaryotic cell biology in the model Saccharomyces cerevisiae. We suggest these proteins are parthenogenesis-inducing factors and our results indicate this would be made possible by a novel mechanism of bacterial-host interaction.

RevDate: 2024-03-26

Soo WF, Gunasekaran K, Ng DX, et al (2024)

Literacy and attitude of Asian youths on dengue and its prevention in an endemic developed community.

Frontiers in public health, 12:1361717.

BACKGROUND: Over the past few decades, the incidence of dengue fever has considerably increased. Effective vector control strategies and specific protection using dengue vaccine are thought to be the key elements to combat dengue. The dengue incidence among the Singapore youths (15-24 years) was second only to that of adults (25-44 years). This study evaluated the knowledge and attitude of Singapore youths on dengue and its preventive measures.

METHODS: A cross-sectional study using online-based questionnaire survey was conducted among Singapore youths from September to November 2022. Data were analyzed for descriptive statistics whereas Chi-squared test, linear regression analysis and Pearson correlation were used to determine the association between demographic factors and youth's attitude on dengue prevention using Rstudio.

RESULTS: A total of 624 respondents completed the survey out of 1822 surveys distributed nation-wide, with a response rate of 34.2% (mean age 17.4 years ± 1.84; 59.3% female; 89.9% Chinese). The mean dengue knowledge scores of participants were 14.1 ±2.8. Univariate analysis showed that teenagers (15-19 years) had significantly higher knowledge score than the young adults (20-24 years) (β=0.82,95%CI = 0.13-1.51, p = 0.021). Majority of them were aware of the Mozzie Wipeout campaign (90.2%) followed by the release of Wolbachia mosquitos (69.1%). Two-thirds of the youths who were aware of Wolbachia and Gravitrap considered that it was effective in reducing dengue infection rates. Participants suggested information about the current dengue infection rate (71.9%) as the most effective of the five proposed strategies to improve uptake of dengue preventive measures. In comparison to young adults, teenagers were more likely to uptake dengue preventive measures if widespread mosquito control practices were implemented (69.1% vs. 42.3%).

CONCLUSION: The overall knowledge of the youths on dengue and its prevention was satisfactory. Future health promotion campaigns targeting the youths should focus on transforming the knowledge into practice.

RevDate: 2024-03-25

Guse K, JE Pietri (2024)

Endosymbiont and gut bacterial communities of the brown-banded cockroach, Supella longipalpa.

PeerJ, 12:e17095.

The brown-banded cockroach (Supella longipalpa) is a widespread nuisance and public health pest. Like the German cockroach (Blattella germanica), this species is adapted to the indoor biome and completes the entirety of its life cycle in human-built structures. Recently, understanding the contributions of commensal and symbiotic microbes to the biology of cockroach pests, as well as the applications of targeting these microbes for pest control, have garnered significant scientific interest. However, relative to B. germanica, the biology of S. longipalpa, including its microbial associations, is understudied. Therefore, the goal of the present study was to quantitatively examine and characterize both the endosymbiont and gut bacterial communities of S. longipalpa for the first time. To do so, bacterial 16S rRNA gene amplicon sequencing was conducted on DNA extracts from whole adult females and males, early instar nymphs, and late instar nymphs. The results demonstrate that the gut microbiome is dominated by two genera of bacteria known to have beneficial probiotic effects in other organisms, namely Lactobacillus and Akkermansia. Furthermore, our data show a significant effect of nymphal development on diversity and variation in the gut microbiome. Lastly, we reveal significant negative correlations between the two intracellular endosymbionts, Blattabacterium and Wolbachia, as well as between Blattabacterium and the gut microbiome, suggesting that Blattabacterium endosymbionts could directly or indirectly influence the composition of other bacterial populations. These findings have implications for understanding the adaptation of S. longipalpa to the indoor biome, its divergence from other indoor cockroach pest species such as B. germanica, the development of novel control approaches that target the microbiome, and fundamental insect-microbe interactions more broadly.

RevDate: 2024-03-20

Hollingsworth BD, Cho C, Vella M, et al (2024)

Economic Optimization of Wolbachia-infected Aedes aegypti release to prevent dengue.

Pest management science [Epub ahead of print].

BACKGROUND: Dengue virus, primarily transmitted by the Aedes aegypti mosquito, is a major public health concern affecting approximately 3.83 billion people worldwide. Recent releases of Wolbachia-transinfected Ae. aegypti in several cities worldwide have shown that it can reduce dengue transmission. However, these releases are costly, and, to date, no framework has been proposed for determining economically optimal release strategies that account for both costs associated with disease risk and releases.

RESULTS: We present a flexible stochastic dynamic programming framework for determining optimal release schedules for Wolbachia-transinfected mosquitoes that balances the cost of dengue infection with the costs of rearing and releasing transinfected mosquitoes. Using an ordinary differential equation model of Wolbachia and dengue in a hypothetical city loosely describing areas at risk of new dengue epidemics, we determined that an all-or-nothing release strategy that quickly brings Wolbachia to fixation is often the optimal solution. Based on this, we examined the optimal facility size, finding that it was less than unitary elastic with respect to the mosquito population size, with a 100% increase in population size resulting in a 50-67% increase in optimal facility size. Further, we found that these results are robust to mosquito life-history parameters and are mostly determined by the mosquito population size and the fitness costs associated with Wolbachia.

CONCLUSIONS: These results reinforce that Wolbachia-transinfected mosquitoes can reduce the cost of dengue epidemics. Further, they emphasize the importance of determining the size of the target population and fitness costs associated with Wolbachia before releases occur. This article is protected by copyright. All rights reserved.

RevDate: 2024-03-20

Du Toit A (2024)

Drosophila sperm sabotage by Wolbachia prophage.

Nature reviews. Microbiology [Epub ahead of print].

RevDate: 2024-03-19

Singh AS, Pathak D, Devi MS, et al (2024)

Antibiotic alters host's gut microbiota, fertility, and antimicrobial peptide gene expression vis-à-vis ampicillin treatment on model organism Drosophila melanogaster.

International microbiology : the official journal of the Spanish Society for Microbiology [Epub ahead of print].

Antibiotics are commonly used to treat infectious diseases; however, persistence is often expressed by the pathogenic bacteria and their long-term relative effect on the host have been neglected. The present study investigated the impact of antibiotics in gut microbiota (GM) and metabolism of host. The effect of ampicillin antibiotics on GM of Drosophila melanogaster was analyzed through deep sequencing of 16S rRNA amplicon gene. The dominant phyla consisted of Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, Planctomycetes, Chloroflexi, Euryarchaeota, Acedobacteria, Verrucomicrobia, and Cyanobacteria. It was found that the composition of GM was significantly altered on administration of antibiotics. On antibiotic treatments, there were decline in relative abundance of Proteobacteria and Firmicutes, while there were increase in relative abundance of Chlorophyta and Bacteroidota. High abundance of 14 genera, viz., Wolbachia, Lactobacillus, Bacillus, Pseudomonas, Thiolamprovum, Pseudoalteromonas, Vibrio, Romboutsia, Staphylococcus, Alteromonas, Clostridium, Lysinibacillus, Litoricola, and Cellulophaga were significant (p ≤ 0.05) upon antibiotic treatment. Particularly, the abundance of Acetobacter was significantly (p ≤ 0.05) declined but increased for Wolbachia. Further, a significant (p ≤ 0.05) increase in Wolbachia endosymbiont of D. melanogaster, Wolbachia endosymbiont of Curculio okumai, and Wolbachia pipientis and a decrease in the Acinetobacter sp. were observed. We observed an increase in functional capacity for biosynthesis of certain nucleotides and the enzyme activities. Further, the decrease in antimicrobial peptide production in the treated group and potential effects on the host's defense mechanisms were observed. This study helps shed light on an often-overlooked dimension, namely the persistence of antibiotics' effects on the host.

RevDate: 2024-03-18

Hague MTJ, Wheeler TB, BS Cooper (2024)

Comparative analysis of Wolbachia maternal transmission and localization in host ovaries.

bioRxiv : the preprint server for biology pii:2024.03.03.583170.

Many insects and other animals carry microbial endosymbionts that influence their reproduction and fitness. These relationships only persist if endosymbionts are reliably transmitted from one host generation to the next. Wolbachia are maternally transmitted endosymbionts found in most insect species, but transmission rates can vary across environments. Maternal transmission of w Mel Wolbachia depends on temperature in natural Drosophila melanogaster hosts and in transinfected Aedes aegypti , where w Mel is used to block pathogens that cause human disease. In D. melanogaster , w Mel transmission declines in the cold as Wolbachia become less abundant in host ovaries and at the posterior pole plasm (the site of germline formation) in mature oocytes. Here, we assess how temperature affects maternal transmission and underlying patterns of Wolbachia localization across 10 Wolbachia strains diverged up to 50 million years-including strains closely related to w Mel-and their natural Drosophila hosts. Many Wolbachia maintain high transmission rates across temperatures, despite highly variable (and sometimes low) levels of Wolbachia in the ovaries and at the developing germline in late-stage oocytes. Identifying strains like closely related w Mel-like Wolbachia with stable transmission across variable environmental conditions may improve the efficacy of Wolbachia -based biocontrol efforts as they expand into globally diverse environments.

RevDate: 2024-03-17

González MA, Ruiz-Arrondo I, Bravo-Barriga D, et al (2024)

Surveillance and screening of Stomoxyinae flies from Mallorca Island (Spain) reveal the absence of selected pathogens but confirm the presence of the endosymbiotic bacterium Wolbachia pipientis.

Research in veterinary science, 171:105206 pii:S0034-5288(24)00072-9 [Epub ahead of print].

Adult brachycera biting flies can significantly impact livestock through both direct effects (reduction of food intake, disturbance, painful bites, and blood loss) and indirect effects (pathogen transmission), leading to substantial economic losses and production damage. This study aimed to assess the presence of blood-sucking flies in six mixed-animal farm environments on the island of Mallorca (Balearic Islands, Spain) by employing multiple trapping methods. Additionally, distribution maps of brachycera biting fly species recorded in Spain were created, based on data extracted thorough review of scientific literature and citizen digital databases. Investigation of several pathogens, including equine infectious anemia virus (EIAV), Anaplasmataceae bacteria, and piroplasm protozoa, was carried out using different PCR targets (18S rRNA, 16S rRNA, groESL, and tat genes). Citizen science databases and literature review corroborated the consistent distribution trend for two Stomoxyinae species, underscoring the importance of citizen collaboration as a complement to traditional entomological surveillance. Our study confirmed the presence of two biting Stomoxyinae species: the prevalent stable fly Stomoxys calcitrans across all sampled farms, and the horn fly Haematobia irritans, which turned out to be less abundant. DNA barcoding techniques validated the identification of the two species. Neither EIAV nor bacterial/protozoan pathogens were detected using the selected PCR targets in either fly species. However, Wolbachia pipientis (clustered in the supergroup A together with the only sequence of W. pipientis from the USA) was identified through PCR targeting 16S rRNA, groESL and wsp genes in all pools of H. irritans (n = 13) collected from two of the examined farms. This study represents the first attempt to investigate pathogens in Stomoxyinae biting flies in Spain. The discovery of the endosymbiotic Wolbachia organism in H. irritans represents the first record in Spain and the second from Europe. This finding holds significant implications for future research on the applications of this bacterium in biocontrol programs.

RevDate: 2024-03-15

Calleros-González P, Ibarra-Juarez A, Lamelas A, et al (2024)

How host species and body part determine the microbial communities of five ambrosia beetle species.

International microbiology : the official journal of the Spanish Society for Microbiology [Epub ahead of print].

The ambrosia beetles are farming insects that feed mainly on their cultivated fungi, which in some occasions are pathogens from forest and fruit trees. We used a culture-independent approach based on 16S and 18S rRNA gene metabarcoding analysis to investigate the diversity and composition of the bacterial and fungal communities associated with five ambrosia beetle species: four species native to America (Monarthrum dimidiatum, Dryocoetoides capucinus, Euwallacea discretus, Corthylus consimilis) and an introduced species (Xylosandrus morigerus). For the bacterial community, the beetle species hosted a broad diversity with 1,579 amplicon sequence variants (ASVs) and 66 genera, while for the fungal community they hosted 288 ASVs and 39 genera. Some microbial groups dominated the community within a host species or a body part (Wolbachia in the head-thorax of E. discretus; Ambrosiella in the head-thorax and abdomen of X. morigerus). The taxonomic composition and structure of the microbial communities appeared to differ between beetle species; this was supported by beta-diversity analysis, which indicated that bacterial and fungal communities were clustered mainly by host species. This study characterizes for the first time the microbial communities associated with unexplored ambrosia beetle species, as well as the factors that affect the composition and taxonomic diversity per se, contributing to the knowledge of the ambrosia beetle system.

RevDate: 2024-03-14

Simmons CP, Donald W, Tagavi L, et al (2024)

Successful introgression of wMel Wolbachia into Aedes aegypti populations in Fiji, Vanuatu and Kiribati.

PLoS neglected tropical diseases, 18(3):e0012022 pii:PNTD-D-23-00714 [Epub ahead of print].

Pacific Island countries have experienced periodic dengue, chikungunya and Zika outbreaks for decades. The prevention and control of these mosquito-borne diseases rely heavily on control of Aedes aegypti mosquitoes, which in most settings are the primary vector. Introgression of the intracellular bacterium Wolbachia pipientis (wMel strain) into Ae. aegypti populations reduces their vector competence and consequently lowers dengue incidence in the human population. Here we describe successful area-wide deployments of wMel-infected Ae. aegypti in Suva, Lautoka, Nadi (Fiji), Port Vila (Vanuatu) and South Tarawa (Kiribati). With community support, weekly releases of wMel-infected Ae. aegypti mosquitoes for between 2 to 5 months resulted in wMel introgression in nearly all locations. Long term monitoring confirmed a high, self-sustaining prevalence of wMel infecting mosquitoes in almost all deployment areas. Measurement of public health outcomes were disrupted by the Covid19 pandemic but are expected to emerge in the coming years.

RevDate: 2024-03-14

Maciel-de-Freitas R, Sauer FG, Kliemke K, et al (2024)

Wolbachia strains wMel and wAlbB differentially affect Aedes aegypti traits related to fecundity.

Microbiology spectrum [Epub ahead of print].

Two Wolbachia strains, wMel and wAlbB, have been transinfected into Aedes aegypti mosquitoes for population replacement with the aim of reducing dengue transmission. Epidemiological data from various endemic sites suggest a pronounced decrease in dengue transmission after implementing this strategy. In this study, we investigated the impact of the Wolbachia strains wMel and wAlbB on Ae. aegypti fitness in a common genetic background. We found that Ae. aegypti females infected with the wMel strain exhibited several significant differences compared with those infected with the wAlbB strain. Specifically, wMel-infected females laid significantly fewer eggs, ingested a lower amount of blood, had a reduced egg production rate, and exhibited a decreased Wolbachia density at a later age compared with mosquitoes infected with the wAlbB strain. Conversely, the wAlbB strain showed only mild negative effects when compared with Wolbachia-uninfected specimens. These differential effects on Ae. aegypti fitness following infection with either wMel or wAlbB may have important implications for the success of population replacement strategies in invading native Ae. aegypti populations in endemic settings. Further research is needed to better understand the underlying mechanisms responsible for these differences in fitness effects and their potential impact on the long-term efficacy of Wolbachia-based dengue control programs.IMPORTANCEThe transmission of arboviruses such as dengue, Zika, and chikungunya is on the rise globally. Among the most promising strategies to reduce arbovirus burden is the release of one out of two strains of Wolbachia-infected Aedes aegypti: wMel and wAlbB. One critical aspect of whether this approach will succeed involves the fitness cost of either Wolbachia strains on mosquito life history traits. For instance, we found that wMel-infected Ae. aegypti females laid significantly fewer eggs, ingested a lower amount of blood, had a reduced egg production rate, and exhibited a decreased Wolbachia density at a later age compared with mosquitoes infected with the wAlbB strain. Conversely, the wAlbB strain showed only mild negative effects when compared with Wolbachia-uninfected specimens. These differential effects on mosquito fitness following infection with either wMel or wAlbB may have important implications for the success of population replacement strategies in invading native Ae. aegypti populations.

RevDate: 2024-03-12

Auguste A, Ris N, Belgaidi Z, et al (2024)

Insect population dynamics under Wolbachia-induced cytoplasmic incompatibility: Puzzle more than buzz in Drosophila suzukii.

PloS one, 19(3):e0300248 pii:PONE-D-23-25628.

In theory, the introduction of individuals infected with an incompatible strain of Wolbachia pipientis into a recipient host population should result in the symbiont invasion and reproductive failures caused by cytoplasmic incompatibility (CI). Modelling studies combining Wolbachia invasion and host population dynamics show that these two processes could interact to cause a transient population decline and, in some conditions, extinction. However, these effects could be sensitive to density dependence, with the Allee effect increasing the probability of extinction, and competition reducing the demographic impact of CI. We tested these predictions with laboratory experiments in the fruit fly Drosophila suzukii and the transinfected Wolbachia strain wTei. Surprisingly, the introduction of wTei into D. suzukii populations at carrying capacity did not result in the expected wTei invasion and transient population decline. In parallel, we found no Allee effect but strong negative density dependence. From these results, we propose that competition interacts in an antagonistic way with Wolbachia-induced cytoplasmic incompatibility on insect population dynamics. If future models and data support this hypothesis, pest management strategies using Wolbachia-induced CI should target populations with negligible competition but a potential Allee effect, for instance at the beginning of the reproductive season.

RevDate: 2024-03-12

Field EN, RC Smith (2023)

Seasonality influences key physiological components contributing to Culex pipiens vector competence.

Frontiers in insect science, 3:1144072.

Mosquitoes are the most important animal vector of disease on the planet, transmitting a variety of pathogens of both medical and veterinary importance. Mosquito-borne diseases display distinct seasonal patterns driven by both environmental and biological variables. However, an important, yet unexplored component of these patterns is the potential for seasonal influences on mosquito physiology that may ultimately influence vector competence. To address this question, we selected Culex pipiens, a primary vector of the West Nile virus (WNV) in the temperate United States, to examine the seasonal impacts on mosquito physiology by examining known immune and bacterial components implicated in mosquito arbovirus infection. Semi-field experiments were performed under spring, summer, and late-summer conditions, corresponding to historically low-, medium-, and high-intensity periods of WNV transmission, respectively. Through these experiments, we observed differences in the expression of immune genes and RNA interference (RNAi) pathway components, as well as changes in the distribution and abundance of Wolbachia in the mosquitoes across seasonal cohorts. Together, these findings support the conclusion that seasonal changes significantly influence mosquito physiology and components of the mosquito microbiome, suggesting that seasonality may impact mosquito susceptibility to pathogen infection, which could account for the temporal patterns in mosquito-borne disease transmission.

RevDate: 2024-03-12

Ahouandjinou MJ, Sovi A, Sidick A, et al (2024)

First report of natural infection of Anopheles gambiae s.s. and Anopheles coluzzii by Wolbachia and Microsporidia in Benin: a cross-sectional study.

Malaria journal, 23(1):72.

BACKGROUND: Recently, bacterial endosymbiont, including Wolbachia and Microsporidia were found to limit the infection of Anopheles mosquitoes with Plasmodium falciparum. This study aimed to investigate the natural presence of key transmission-blocking endosymbionts in Anopheles gambiae and Anopheles coluzzii in Southern Benin.

METHODS: The present study was conducted in seven communes (Cotonou, Porto-Novo, Aguégués, Ifangni, Pobè Athiémé, and Grand-Popo) of Southern Benin. Anopheles were collected using indoor/outdoor Human Landing Catches (HLCs) and Pyrethrum Spray Catches (PSCs). Following morphological identification, PCR was used to identify An. gambiae sensu lato (s.l.) to species level and to screen for the presence of both Wolbachia and Microsporidia. Plasmodium falciparum sporozoite infection was also assessed using ELISA.

RESULTS: Overall, species composition in An. gambiae s.l. was 53.7% An. coluzzii, while the remainder was An. gambiae sensu stricto (s.s.). Combined data of the two sampling techniques revealed a mean infection prevalence with Wolbachia of 5.1% (95% CI 0.90-18.6) and 1.3% (95% CI 0.07-7.8) in An. gambiae s.s. and An. coluzzii, respectively. The mean infection prevalence with Microsporidia was 41.0% (95% CI 25.9-57.8) for An. gambiae s.s. and 57.0% (95% CI 45.4-67.9) for An. coluzzii. Wolbachia was only observed in Ifangni, Pobè, and Cotonou, while Microsporidia was detected in all study communes. Aggregated data for HLCs and PSCs showed a sporozoite rate (SR) of 0.80% (95% CI 0.09-2.87) and 0.69% (95% CI 0.09-2.87) for An. gambiae and An. coluzzii, respectively, with a mean of 0.74% (95% CI 0.20-1.90). Of the four individual mosquitoes which harboured P. falciparum, none were also infected with Wolbachia and one contained Microsporidia.

CONCLUSIONS: The present study is the first report of natural infections of field-collected An. gambiae s.l. populations from Benin with Wolbachia and Microsporidia. Sustained efforts should be made to widen the spectrum of bacteria identified in mosquitoes, with the potential to develop endosymbiont-based control tools; such interventions could be the game-changer in the control of malaria and arboviral disease transmission.

RevDate: 2024-03-12

Fernández MB, Bleidorn C, LA Calcaterra (2022)

Wolbachia Infection in Native Populations of the Invasive Tawny Crazy Ant Nylanderia fulva.

Frontiers in insect science, 2:905803.

Antagonistic interactions can affect population growth and dispersal of an invasive species. Wolbachia are intracellular endosymbiont bacteria that infect arthropod and nematode hosts and are able to manipulate reproduction, which in some cases leads to cocladogenesis. Moreover, the presence of the strictly maternally transferred Wolbachia in a population can indirectly induce selective sweeps on the hosts' mitochondria. Ants have a Wolbachia infection rate of about 34%, which makes phylogenetic studies using mitochondrial markers vulnerable of being confounded by the effect of the endosymbiont. Nylanderia fulva is an invasive ant native to South America, considered a pest in the United States. Its distribution and biology are poorly known in its native range, and the taxonomic identity of this and its closely related species, Nylanderia pubens, has only recently been understood with the aid of molecular phylogenies. Aiming at estimating robust phylogenetic relationships of N. fulva in its native range, we investigated the presence and pattern of Wolbachia infection in populations of N. fulva from Argentina, part of its native range, to account for its possible effect on the host population structure. Using the ftsZ gene, 30 nests of N. fulva and four from sympatric Nylanderia species were screened for the presence of Wolbachia. We sequenced the MLST genes, the highly variable gene wsp, as well as glyQ, a novel target gene for which new primers were designed. Phylogeny of the ants was estimated using mtDNA (COI). We found supergroup A Wolbachia strains infecting 73% of N. fulva nests and two nests of Nylanderia sp. 1. Wolbachia phylogenetic tree inferred with MLST genes is partially congruent with the host phylogeny topology, with the exception of a lineage of strains shared by ants from different N. fulva clades. Furthermore, by comparing with Wolbachia sequences infecting other ants, we found that the strains infecting different N. fulva clades are not monophyletic. Our findings suggest there are three recent independent horizontally transmitted Wolbachia infections in N. fulva, and we found no evidence of influence of Wolbachia in the host mtDNA based phylogeny.

RevDate: 2024-03-10

Ateutchia-Ngouanet S, Nanfack-Minkeu F, Mavridis K, et al (2024)

Monitoring Aedes populations for arboviruses, Wolbachia, insecticide resistance and its mechanisms in various agroecosystems in Benin.

Acta tropica pii:S0001-706X(24)00062-7 [Epub ahead of print].

Aedes mosquitoes are the main vectors of arboviruses in Benin. Cases of dengue have been reported in Benin with all four serotypes of the virus actively circulating in this region. Some agricultural settings are known to harbor Aedes vectors responsible for the transmission of arboviruses. The massive use of certain insecticides in agricultural settings has probably contributed to insecticide resistance in these vectors. In Benin, the susceptibility of arbovirus vectors to insecticides is poorly studied. In addition, the distribution of Wolbachia spp., which is used against some arboviruses is unknown. Moreover, there is limited information regarding the vectors responsible for the transmission of arboviruses in Benin. This present study monitored the species composition, arboviruses, and Wolbachia symbiont status, as well as the phenotypic and molecular insecticide resistance profile of Aedes populations from three agroecosystems in Benin. Aedes species identification was performed morphologically and confirmed using qPCR. (RT)-qPCR assay was applied for monitoring the presence of DENV, CHIKV, ZIKV, and WNV pathogens as well as for naturally occurring Wolbachia symbionts. Insecticide resistance was assessed phenotypically, by permethrin (0.75%) exposure of Adults (F0) using World Health Organization (WHO) bioassay protocols, and at the molecular level, using TaqMan (RT)-qPCR assays for assessing knock-down resistance (kdr) mutations (F1534C, V1016G/I, and S989P) and the expression levels of eight detoxification genes (P450s from the CYP9 and CYP6 families, carboxylesterases and glutathione-S-transferases). Aedes aegypti (Ae. aegypti) mosquitoes were the most abundant (93.9%) in the three agroecosystems studied, followed by Aedes albopictus (Ae. albopictus) mosquitoes (6.1%). No arboviruses were detected in the study's mosquito populations. Naturally occurring Wolbachia symbionts were present in 7 pools out of 15 pools tested. This could influence the effectiveness of vector control strategies based on exogenously introduced Wolbachia, all present in the three agroecosystems. Full susceptibility to permethrin was observed in all tested populations of Ae. albopictus. On the contrary, Ae. aegypti were found to be resistant in all three agroecosystem sites except for banana plantation sites, where full susceptibility was observed. Molecular analysis revealed that individual target site resistance kdr mutations F1534C and V1016G/I were detected in most Ae. aegypti populations. Additionally, double mutant (F1534C + V1016G/I) mosquitoes were found in some populations, and in one case, triple mutant (F1534C + V1016G/I + S989P) mosquitoes were detected. Metabolic resistance, as reflected by overexpression of three P450 genes (CYP6BB2, CYP9J26, and CYP9J32), was also detected in Ae. aegypti mosquitoes. Our study provides information that could be used to strategize future vector control strategies and highlights the importance of continuing vector surveillance. Future studies should assess the effect of piperonyl butoxide (PBO) on metabolic resistance and identify the different strains of Wolbachia spp., to choose the best vector control strategies in Benin.

RevDate: 2024-03-09

Zurita A, Trujillo I, C Cutillas (2024)

New records of pathogenic bacteria in different species of fleas collected from domestic and peridomestic animals in Spain. A potential zoonotic threat?.

Comparative immunology, microbiology and infectious diseases, 107:102153 pii:S0147-9571(24)00030-4 [Epub ahead of print].

Climate change is causing many vectors of infectious diseases to expand their geographic distribution as well as the pathogens they transmit are also conditioned by temperature for their multiplication. Within this context, it is worth highlighting the significant role that fleas can play as vectors of important pathogenic bacteria. For this purpose, our efforts focused on detecting and identifying a total of 9 bacterial genera (Rickettsia sp.; Bartonella sp.; Yersinia sp.; Wolbachia sp., Mycobacterium sp., Leishmania sp., Borrelia sp., Francisella sp. and Coxiella sp.) within fleas isolated from domestic and peridomestic animals in the southwestern region of Spain (Andalusia). Over a 19-months period, we obtained flea samples from dogs, cats and hedgehogs. A total of 812 fleas was collected for this study. Five different species were morphologically identified, including C. felis, C. canis, S. cuniculi, P. irritans, and A. erinacei. Wolbachia sp. was detected in all five species identified in our study which a total prevalence of 86%. Within Rickettsia genus, two different species, R. felis and R. asembonensis were mainly identified in C. felis and A. erinacei, respectively. On the other hand, our results revealed a total of 131 fleas testing positive for the presence of Bartonella sp., representing a prevalence rate of 16% for this genus identifying two species B. henselae and B. clarridgeiae. Lastly, both Y. pestis and L. infantum were detected in DNA of P. irritans and C. felis, respectively isolated from dogs. With these data we update the list of bacterial zoonotic agents found in fleas in Spain, emphasizing the need to continue conducting future experimental studies to assess and confirm the potential vectorial role of certain synanthropic fleas.

RevDate: 2024-03-08

Moore CO, André MR, Šlapeta J, et al (2024)

Vector biology of the cat flea Ctenocephalides felis.

Trends in parasitology pii:S1471-4922(24)00031-X [Epub ahead of print].

Ctenocephalides felis, the cat flea, is among the most prevalent and widely dispersed vectors worldwide. Unfortunately, research on C. felis and associated pathogens (Bartonella and Rickettsia spp.) lags behind that of other vectors and vector-borne pathogens. Therefore, we aimed to review fundamental aspects of C. felis as a vector (behavior, epidemiology, phylogenetics, immunology, and microbiome composition) with an emphasis on key techniques and research avenues employed in other vector species. Future laboratory C. felis experimental infections with Bartonella, Rickettsia, and Wolbachia species/strains should examine the vector-pathogen interface utilizing contemporary visualization, transcriptomic, and gene-editing techniques. Further environmental sampling will inform the range and prevalence of C. felis and associated pathogens, improving the accuracy of vector and pathogen modeling to improve infection/infestation risk assessment and diagnostic recommendations.

RevDate: 2024-03-08

Carlassara M, Khorramnejad A, Oker H, et al (2024)

Population-specific responses to developmental temperature in the arboviral vector Aedes albopictus: Implications for climate change.

Global change biology, 30(3):e17226.

The increase of environmental temperature due to current global warming is not only favouring the expansion of the distribution range of many insect species, but it is also changing their phenology. Insect phenology is tightly linked to developmental timing, which is regulated by environmental temperatures. However, the degree to which the effects of developmental temperatures extend across developmental stages and their inter-stage relationships have not been thoroughly quantified in mosquitoes. Here, we used the mosquito Aedes albopictus, which is an aggressive invasive species and an arboviral vector, to study how developmental temperature influences fitness across developmental stages, thermal traits, energy reserves, transcriptome and Wolbachia prevalence in laboratory-reared populations originally collected from either temperate or tropical regions. We show that hatchability, larval and pupal viability and developmental speed are strongly influenced by temperature, and these effects extend to wing length, body mass, longevity and content of water, protein and lipids in adults in a population-specific manner. On the contrary, neither adult thermal preference nor heat resistance significantly change with temperature. Wolbachia density was generally lower in adult mosquitoes reared at 18°C than at other tested temperatures, and transcriptome analysis showed enrichment for functions linked to stress responses (i.e. cuticle proteins and chitin, cytochrome p450 and heat shock proteins) in mosquitoes reared at both 18 and 32°C. Our data showed an overall reduced vector fitness performance when mosquitoes were reared at 32°C, and the absence of isomorphy in the relationship between developmental stages and temperature in the laboratory population deriving from larvae collected in northern Italy. Altogether, these results have important implications for reliable model projections of the invasion potentials of Ae. albopictus and its epidemiological impact.

RevDate: 2024-03-07

Kaur R, McGarry A, Shropshire JD, et al (2024)

Prophage proteins alter long noncoding RNA and DNA of developing sperm to induce a paternal-effect lethality.

Science (New York, N.Y.), 383(6687):1111-1117.

The extent to which prophage proteins interact with eukaryotic macromolecules is largely unknown. In this work, we show that cytoplasmic incompatibility factor A (CifA) and B (CifB) proteins, encoded by prophage WO of the endosymbiont Wolbachia, alter long noncoding RNA (lncRNA) and DNA during Drosophila sperm development to establish a paternal-effect embryonic lethality known as cytoplasmic incompatibility (CI). CifA is a ribonuclease (RNase) that depletes a spermatocyte lncRNA important for the histone-to-protamine transition of spermiogenesis. Both CifA and CifB are deoxyribonucleases (DNases) that elevate DNA damage in late spermiogenesis. lncRNA knockdown enhances CI, and mutagenesis links lncRNA depletion and subsequent sperm chromatin integrity changes to embryonic DNA damage and CI. Hence, prophage proteins interact with eukaryotic macromolecules during gametogenesis to create a symbiosis that is fundamental to insect evolution and vector control.

RevDate: 2024-03-07

Urakova N, Joseph RE, Huntsinger A, et al (2024)

Alpha-mannosidase-2 modulates arbovirus infection in a pathogen- and Wolbachia-specific manner in Aedes aegypti mosquitoes.

Insect molecular biology [Epub ahead of print].

Multiple Wolbachia strains can block pathogen infection, replication and/or transmission in Aedes aegypti mosquitoes under both laboratory and field conditions. However, Wolbachia effects on pathogens can be highly variable across systems and the factors governing this variability are not well understood. It is increasingly clear that the mosquito host is not a passive player in which Wolbachia governs pathogen transmission phenotypes; rather, the genetics of the host can significantly modulate Wolbachia-mediated pathogen blocking. Specifically, previous work linked variation in Wolbachia pathogen blocking to polymorphisms in the mosquito alpha-mannosidase-2 (αMan2) gene. Here we use CRISPR-Cas9 mutagenesis to functionally test this association. We developed αMan2 knockouts and examined effects on both Wolbachia and virus levels, using dengue virus (DENV; Flaviviridae) and Mayaro virus (MAYV; Togaviridae). Wolbachia titres were significantly elevated in αMan2 knockout (KO) mosquitoes, but there were complex interactions with virus infection and replication. In Wolbachia-uninfected mosquitoes, the αMan2 KO mutation was associated with decreased DENV titres, but in a Wolbachia-infected background, the αMan2 KO mutation significantly increased virus titres. In contrast, the αMan2 KO mutation significantly increased MAYV replication in Wolbachia-uninfected mosquitoes and did not affect Wolbachia-mediated virus blocking. These results demonstrate that αMan2 modulates arbovirus infection in A. aegypti mosquitoes in a pathogen- and Wolbachia-specific manner, and that Wolbachia-mediated pathogen blocking is a complex phenotype dependent on the mosquito host genotype and the pathogen. These results have a significant impact for the design and use of Wolbachia-based strategies to control vector-borne pathogens.

RevDate: 2024-03-07

Mancini MV, Murdochy SM, Bilgo E, et al (2024)

Wolbachia strain wAlbB shows favourable characteristics for dengue control use in Aedes aegypti from Burkina Faso.

Environmental microbiology, 26(3):e16588.

Dengue represents an increasing public health burden worldwide. In Africa, underreporting and misdiagnosis often mask its true epidemiology, and dengue is likely to be both more widespread than reported data suggest and increasing in incidence and distribution. Wolbachia-based dengue control is underway in Asia and the Americas but has not to date been deployed in Africa. Due to the genetic heterogeneity of African Aedes aegypti populations and the complexity of the host-symbiont interactions, characterization of key parameters of Wolbachia-carrying mosquitoes is paramount for determining the potential of the system as a control tool for dengue in Africa. The wAlbB Wolbachia strain was stably introduced into an African Ae. aegypti population by introgression, and showed high intracellular density in whole bodies and different mosquito tissues; high intracellular density was also maintained following larval rearing at high temperatures. No effect on the adult lifespan induced by Wolbachia presence was detected. Moreover, the ability of this strain to strongly inhibit DENV-2 dissemination and transmission in the host was also demonstrated in the African background. Our findings suggest the potential of harnessing Wolbachia for dengue control for African populations of Ae. aegypti.

RevDate: 2024-03-06

Pérez-Guerra CL, Rosado-Santiago C, Ramos SA, et al (2024)

Acceptability of emergent Aedes aegypti vector control methods in Ponce, Puerto Rico: A qualitative assessment.

PLOS global public health, 4(3):e0002744 pii:PGPH-D-23-01366.

Aedes aegypti control has been fraught with challenges in Puerto Rico. The government has implemented commonly used vector control methods, but arboviral epidemics still occur. It is necessary to explore new Ae. aegypti control methods. This study aimed to understand the perceptions of community members in Ponce, Puerto Rico about emergent and traditional Ae. aegypti vector control methods and determine their acceptability and support for these methods. We identified the type of information needed to increase support for emergent vector control methods, and the preferred strategies to disseminate this information. Four group discussions were conducted with a total of 32 participants representing eight of the 14 clusters participating in the Communities Organized for the Prevention of Arboviruses (COPA), a project designed to mobilize communities in Ponce, Puerto Rico to prevent diseases transmitted by mosquitoes. Group discussions began with an overview of different methods used for controlling Ae. aegypti mosquitoes. These overviews facilitated participant understanding of the mosquito control methods presented. Use of source reduction, autocidal gravid ovitraps (AGO), and manual application of larvicide for arboviral mosquito control received support from almost all participants. Vector control methods that use more familiar techniques in Puerto Rico such as truck-mounted larvicide spraying (TMLS) and insecticide residual spraying received support from most participants. More than half of participants supported the use of emergent mosquito control methods including Wolbachia suppression, Wolbachia replacement, or genetically modified mosquitoes (GMM). Participants preferred to receive vector control information through house-to-house visits with the distribution of written materials, followed by dissemination of information through traditional (i.e., radio, television) and social media. The detailed information resulting from this study was used to develop messages for a communications campaign to garner future community support. Community acceptance and support are critical for the success of vector control programs using emergent mosquito control methods.

RevDate: 2024-03-04

Dye D, JW Cain (2024)

Efficacy of Wolbachia-based mosquito control: Predictions of a spatially discrete mathematical model.

PloS one, 19(3):e0297964 pii:PONE-D-23-27458.

Wolbachia is an endosymbiont bacterium present in many insect species. When Wolbachia-carrying male Aedes aegypti mosquitoes mate with non-carrier females, their embryos are not viable due to cytoplasmic incompatibility. This phenomenon has been exploited successfully for the purpose of controlling mosquito populations and the spread of mosquito-borne illnesses: Wolbachia carriers are bred and released into the environment. Because Wolbachia is not harmful to humans, this method of mosquito control is regarded as a safer alternative to pesticide spraying. In this article, we introduce a mathematical framework for exploring (i) whether a one-time release of Wolbachia carriers can elicit a sustained presence of carriers near the release site, and (ii) the extent to which spatial propagation of carriers may allow them to establish fixation in other territories. While some prior studies have formulated mosquito dispersal models using advection-reaction-diffusion PDEs, the predictive power of such models requires careful ecological mapping: advection and diffusion coefficients exhibit significant spatial dependence due to heterogeneity of resources and topography. Here, we adopt a courser-grained view, regarding the environment as a network of discrete, diffusively-coupled "habitats"-distinct zones of high mosquito density such as stagnant ponds. We extend two previously published single-habitat mosquito models to multiple habitats, and calculate rates of migration between pairs of habitats using dispersal kernels. Our primary results are quantitative estimates regarding how the success of carrier fixation in one or more habitats is determined by: the number of carriers released, sizes of habitats, distances between habitats, and the rate of migration between habitats. Besides yielding sensible and potentially useful predictions regarding the success of Wolbachia-based control, our framework applies to other approaches (e.g., gene drives) and contexts beyond the realm of insect pest control.

RevDate: 2024-03-02

Walt HK, King JG, Sheele JM, et al (2024)

Do bed bugs transmit human viruses, or do humans spread bed bugs and their viruses? A worldwide survey of the bed bug RNA virosphere.

Virus research pii:S0168-1702(24)00042-X [Epub ahead of print].

BED BUGS (HEMIPTERA: : Cimicidae) are a globally distributed hematophagous pest that routinely feed on humans. Unlike many blood-sucking arthropods, they have never been linked to pathogen transmission in a natural setting, and despite increasing interest in their role as disease vectors, little is known about the viruses that bed bugs naturally harbor. Here, we present a global-scale survey of the bed bug RNA virosphere. We sequenced the metatranscriptomes of 22 individual bed bugs (Cimex lectularius and Cimex hemipterus) from 8 locations around the world. We detected sequences from two known bed bug viruses (Shuangao bedbug virus 1 and Shuangao bedbug virus 2) which extends their geographical range. We identified three novel bed bug virus sequences from a tenui-like virus (Bunyavirales), a toti-like virus (Ghabrivirales), and a luteo-like virus (Tolivirales). Interestingly, some of the bed bug viruses branch near to insect-transmitted plant-infecting viruses, opening questions regarding the evolution of plant virus infection. When we analyzed the viral sequences by their host's collection location, we found unexpected patterns of geographical diversity that may reflect humans' role in bed bug dispersal. Additionally, we investigated the effect that Wolbachia, the primary bed bug endosymbiont, may have on viral abundance and found that Wolbachia infection neither promotes nor inhibits viral infection. Finally, our results provide no evidence that bed bugs transmit any known human pathogenic viruses.

RevDate: 2024-03-01

Aldridge RL, Gibson S, KJ Linthicum (2024)

Aedes aegypti Controls AE. Aegypti: SIT and IIT-An Overview.

Journal of the American Mosquito Control Association, 40(1):32-49.

The sterile insect technique (SIT) and the incompatible insect technique (IIT) are emerging and potentially revolutionary tools for controlling Aedes aegypti (L.), a prominent worldwide mosquito vector threat to humans that is notoriously difficult to reduce or eliminate in intervention areas using traditional integrated vector management (IVM) approaches. Here we provide an overview of the discovery, development, and application of SIT and IIT to Ae. aegypti control, and innovations and advances in technology, including transgenics, that could elevate these techniques to a worldwide sustainable solution to Ae. aegypti when combined with other IVM practices.

RevDate: 2024-03-01

Cantin LJ, Dunning Hotopp JC, JM Foster (2024)

Improved metagenome assemblies through selective enrichment of bacterial genomic DNA from eukaryotic host genomic DNA using ATAC-seq.

Frontiers in microbiology, 15:1352378.

Genomics can be used to study the complex relationships between hosts and their microbiota. Many bacteria cannot be cultured in the laboratory, making it difficult to obtain adequate amounts of bacterial DNA and to limit host DNA contamination for the construction of metagenome-assembled genomes (MAGs). For example, Wolbachia is a genus of exclusively obligate intracellular bacteria that live in a wide range of arthropods and some nematodes. While Wolbachia endosymbionts are frequently described as facultative reproductive parasites in arthropods, the bacteria are obligate mutualistic endosymbionts of filarial worms. Here, we achieve 50-fold enrichment of bacterial sequences using ATAC-seq (Assay for Transposase-Accessible Chromatin using sequencing) with Brugia malayi nematodes, containing Wolbachia (wBm). ATAC-seq uses the Tn5 transposase to cut and attach Illumina sequencing adapters to accessible DNA lacking histones, typically thought to be open chromatin. Bacterial and mitochondrial DNA in the lysates are also cut preferentially since they lack histones, leading to the enrichment of these sequences. The benefits of this include minimal tissue input (<1 mg of tissue), a quick protocol (<4 h), low sequencing costs, less bias, correct assembly of lateral gene transfers and no prior sequence knowledge required. We assembled the wBm genome with as few as 1 million Illumina short paired-end reads with >97% coverage of the published genome, compared to only 12% coverage with the standard gDNA libraries. We found significant bacterial sequence enrichment that facilitated genome assembly in previously published ATAC-seq data sets from human cells infected with Mycobacterium tuberculosis and C. elegans contaminated with their food source, the OP50 strain of E. coli. These results demonstrate the feasibility and benefits of using ATAC-seq to easily obtain bacterial genomes to aid in symbiosis, infectious disease, and microbiome research.

RevDate: 2024-02-27

Liu K, Fang S, Li Q, et al (2024)

Effectiveness evaluation of mosquito suppression strategies on dengue transmission under changing temperature and precipitation.

Acta tropica pii:S0001-706X(24)00043-3 [Epub ahead of print].

Widespread resurgence of dengue outbreaks has seriously threatened the global health. Due to lack of treatments and vaccines, one key strategy in dengue control is to reduce the vector population size. As an environment-friendly mosquito control approach, releasing male mosquitoes transinfected with specific Wolbachia strain into the field to suppress the wild mosquito population size has become wildly accepted. The current study evaluates the effectiveness of this suppression strategy on dengue control under changing temperature and precipitation profiles. We formulate a mathematical model which includes larval intra-specific competition, the maturation period for mosquitoes, the extrinsic incubation period (EIP) and intrinsic incubation period (IIP). The persistence of mosquitoes and disease is discussed in terms of two basic reproduction numbers (RM and R0) and the release ratio pw. Further numerical simulations are carried out to not only validate theoretical results, but also provide interesting quantitative observations. Sensitivity analysis on the reproduction numbers, peak size, peak time and the final epidemic size is performed with respect to model parameters, which highlights effective control measures against dengue transmission. Moreover, by assuming temperature and precipitation dependent mosquito-related parameters, the model can be used to project the effectiveness of releasing Wolbachia-carrying males under climatic variations. It is shown that the effectiveness of various control strategies is highly dependent on the changing temperature and precipitation profiles. In particular, the model projects that it is most challenging to control the disease at the favorable temperature (around 27∼30[∘]C) and precipitation (5∼8mm/day) range, during which the basic reproduction number R0 is very high and more Wolbachia-infected males should be released.

RevDate: 2024-02-26

Yan J, Green K, Noel K, et al (2024)

Effects of seasonality and developed land cover on Culex mosquito abundance and microbiome diversity.

Frontiers in microbiology, 15:1332970.

The vectorial capacity of mosquitoes, which influences the dynamics of vector-borne disease transmission, is intricately linked to mosquito abundance and the composition and diversity of their associated microbiomes. However, the influence of environmental factors on mosquito populations and microbiome diversity remains underexplored. Here we examined the effects of seasonality and developed land cover on Culex mosquito abundance and bacterial diversity. Biweekly field sampling of female Culex mosquitoes was conducted using gravid and CDC light traps, spanning summer to autumn across varying developed land cover levels in two urban areas in Central Illinois. Mosquito abundance was assessed by the number of mosquitoes captured per trap night and compared across seasons and developed levels. The mean mosquito abundance for gravid and light traps was 12.96 ± 2.15 and 7.67 ± 1.44, respectively. Notably, higher levels of developed land cover exhibited higher Culex abundance than the low level for light traps, but no significant difference was found between summer and early autumn. In gravid traps, no significant differences were detected across seasons or developed levels. Microbial analysis of the mosquito microbiome revealed that Proteobacteria and Wolbachia, with a mean relative abundance of 80.77 and 52.66% respectively, were identified as the most dominant bacterial phylum and genus. Their relative abundance remained consistent across seasons and developed land cover levels, with negligible variations. Alpha diversity, as measured by observed species, Chao1, Shannon, and Simpson, showed slightly higher values in early-autumn compared to late-summer. A notable pattern of bacterial diversity, as indicated by all four diversity indexes, is evident across varying levels of land development. Significantly, high or intermediate developed levels consistently showed reduced alpha diversity when compared to the lower level. This underscores the pronounced impact of anthropogenic ecological disturbances in shaping mosquito microbiomes. Beta diversity analysis revealed no significant dissimilarities in bacterial community composition across seasons and developed levels, although some separation was noted among different levels of developed land cover. These findings highlight the significant role of environmental factors in shaping mosquito abundance and their associated microbiomes, with potential implications for the vectorial capacity in the transmission of vector-borne diseases.

RevDate: 2024-02-24

Corrêa-Antônio J, David MR, Couto-Lima D, et al (2024)

DENV-1 Titer Impacts Viral Blocking in wMel Aedes aegypti with Brazilian Genetic Background.

Viruses, 16(2): pii:v16020214.

Several countries have been using Wolbachia deployments to replace highly competent native Aedes aegypti populations with Wolbachia-carrying mosquitoes with lower susceptibility to arboviruses such as dengue, Zika, and chikungunya. In Rio de Janeiro, Wolbachia deployments started in 2015 and still present a moderate introgression with a modest reduction in dengue cases in humans (38%). Here, we evaluated the vector competence of wild-type and wMel-infected Ae. aegypti with a Brazilian genetic background to investigate whether virus leakage could contribute to the observed outcomes in Brazil. We collected the specimens in three areas of Rio de Janeiro with distinct frequencies of mosquitoes with wMel strain and two areas with wild Ae. aegypti. The mosquitoes were orally exposed to two titers of DENV-1 and the saliva of DENV-1-infected Ae. aegypti was microinjected into wMel-free mosquitoes to check their infectivity. When infected with the high DENV-1 titer, the presence of wMel did not avoid viral infection in mosquitoes' bodies and saliva but DENV-1-infected wMel mosquitoes produced lower viral loads than wMel-free mosquitoes. On the other hand, wMel mosquitoes infected with the low DENV-1 titer were less susceptible to virus infection than wMel-free mosquitoes, although once infected, wMel and wMel-free mosquitoes exhibited similar viral loads in the body and the saliva. Our results showed viral leakage in 60% of the saliva of wMel mosquitoes with Brazilian background; thus, sustained surveillance is imperative to monitor the presence of other circulating DENV-1 strains capable of overcoming the Wolbachia blocking phenotype, enabling timely implementation of action plans.

RevDate: 2024-02-24

Voronin D, Tricoche N, Peguero R, et al (2024)

Repurposed Drugs That Activate Autophagy in Filarial Worms Act as Effective Macrofilaricides.

Pharmaceutics, 16(2): pii:pharmaceutics16020256.

Onchocerciasis and lymphatic filariasis are two neglected tropical diseases caused by filarial nematodes that utilize insect vectors for transmission to their human hosts. Current control strategies are based on annual or biannual mass drug administration (MDA) of the drugs Ivermectin or Ivermectin plus Albendazole, respectively. These drug regimens kill the first-stage larvae of filarial worms (i.e., microfilariae) and interrupt the transmission of infections. MDA programs for these microfilaricidal drugs must be given over the lifetime of the filarial adult worms, which can reach 15 years in the case of Onchocerca volvulus. This is problematic because of suboptimal responses to ivermectin in various endemic regions and inefficient reduction of transmission even after decades of MDA. There is an urgent need for the development of novel alternative treatments to support the 2030 elimination goals of onchocerciasis and lymphatic filariasis. One successful approach has been to target Wolbachia, obligatory endosymbiotic bacteria on which filarial worms are dependent for their survival and reproduction within the human host. A 4-6-week antibiotic therapy with doxycycline, for example, resulted in the loss of Wolbachia that subsequently led to extensive apoptosis of somatic cells, germline, embryos, and microfilariae, as well as inhibition of fourth-stage larval development. However, this long-course regimen has limited use in MDA programs. As an alternative approach to the use of bacteriostatic antibiotics, in this study, we focused on autophagy-inducing compounds, which we hypothesized could disturb various pathways involved in the interdependency between Wolbachia and filarial worms. We demonstrated that several such compounds, including Niclosamide, an FDA-approved drug, Niclosamide ethanolamine (NEN), and Rottlerin, a natural product derived from Kamala trees, significantly reduced the levels of Wolbachia in vitro. Moreover, when these compounds were used in vivo to treat Brugia pahangi-infected gerbils, Niclosamide and NEN significantly decreased adult worm survival, reduced the release of microfilariae, and decreased embryonic development depending on the regimen and dose used. All three drugs given orally significantly reduced Wolbachia loads and induced an increase in levels of lysosome-associated membrane protein in worms from treated animals, suggesting that Niclosamide, NEN, and Rottlerin were effective in causing drug-induced autophagy in these filarial worms. These repurposed drugs provide a new avenue for the clearance of adult worms in filarial infections.

RevDate: 2024-02-23

Zhang X, PM Ferree (2024)

PSRs: Selfish chromosomes that manipulate reproductive development.

Seminars in cell & developmental biology, 159-160:66-73 pii:S1084-9521(24)00020-X [Epub ahead of print].

B chromosomes are intriguing "selfish" genetic elements, many of which exhibit higher-than-Mendelian transmission. This perspective highlights a group of B chromosomes known as Paternal Sex Ratio chromosomes (PSRs), which are found in several insects with haplo-diploid reproduction. PSRs harshly alter the organism's reproduction to facilitate their own inheritance. A manifestation of this effect is the conversion of female destined individuals into males. Key to this conversion is the mysterious ability of PSRs to cause elimination of the sperm-inherited half of the genome during zygote formation. Here we discuss how PSRs were discovered, what is known about how they alter paternal chromatin dynamics to cause sex conversion, and how PSR-induced genome elimination is different from other forms of programmed genome elimination in different insects. PSRs also stand out because their DNA sequence compositions differ in remarkable ways from their insect's essential chromosomes, a characteristic suggestive of interspecies origins. Broadly, we also highlight poorly understood aspects of PSR dynamics that need to be investigated.

RevDate: 2024-02-23

Lamichhane B, Brockway C, Evasco K, et al (2024)

Metatranscriptomic Sequencing of Medically Important Mosquitoes Reveals Extensive Diversity of RNA Viruses and Other Microbial Communities in Western Australia.

Pathogens (Basel, Switzerland), 13(2): pii:pathogens13020107.

Mosquitoes harbor a wide diversity of microorganisms, including viruses that are human pathogens, or that are insect specific. We used metatranscriptomics, an unbiased high-throughput molecular approach, to describe the composition of viral and other microbial communities in six medically important mosquito species from across Western Australia: Aedes vigilax, Culex annulirostris, Cx. australicus, Cx. globocoxitus, Cx. pipiens biotype molestus, and Cx. quinquefasciatus. We identified 42 viral species, including 13 novel viruses, from 19 families. Culex mosquitoes exhibited a significantly higher diversity of viruses than Aedes mosquitoes, and no virus was shared between the two genera. Comparison of mosquito populations revealed a heterogenous distribution of viruses between geographical regions and between closely related species, suggesting that geography and host species may play a role in shaping virome composition. We also detected bacterial and parasitic microorganisms, among which Wolbachia bacteria were detected in three members of the Cx. pipiens complex, Cx. australicus, Cx. pipiens biotype molestus, and Cx. quinquefasciatus. In summary, our unbiased metatranscriptomics approach provides important insights into viral and other microbial diversity in Western Australian mosquitoes that vector medically important viruses.

RevDate: 2024-02-23

Zhu X, Li J, He A, et al (2024)

Developmental Shifts in the Microbiome of a Cosmopolitan Pest: Unraveling the Role of Wolbachia and Dominant Bacteria.

Insects, 15(2): pii:insects15020132.

Wolbachia bacteria (phylum Proteobacteria) are ubiquitous intracellular parasites of diverse invertebrates. In insects, coevolution has forged mutualistic associations with Wolbachia species, influencing reproduction, immunity, development, pathogen resistance, and overall fitness. However, the impact of Wolbachia on other microbial associates within the insect microbiome, which are crucial for host fitness, remains less explored. The diamondback moth (Plutella xylostella), a major pest of cruciferous vegetables worldwide, harbors the dominant Wolbachia strain plutWB1, known to distort its sex ratio. This study investigated the bacterial community diversity and dynamics across different developmental life stages and Wolbachia infection states in P. xylostella using high-throughput 16S rDNA amplicon sequencing. Proteobacteria and Firmicutes dominated the P. xylostella microbiome regardless of life stage or Wolbachia infection. However, the relative abundance of dominant genera, including an unclassified genus of Enterobacteriaceae, Wolbachia, Carnobacterium, and Delftia tsuruhatensis, displayed significant stage-specific variations. While significant differences in bacterial diversity and composition were observed across life stages, Wolbachia infection had no substantial impact on overall diversity. Nonetheless, relative abundances of specific genera differed between infection states. Notably, Wolbachia exhibited a stable, high relative abundance across all stages and negatively correlated with an unclassified genus of Enterobacteriaceae, Delftia tsuruhatensis, and Carnobacterium. Our findings provide a foundational understanding of the complex interplay between the host, Wolbachia, and the associated microbiome in P. xylostella, paving the way for a deeper understanding of their complex interactions and potential implications for pest control strategies.

RevDate: 2024-02-23

Budrys E, Orlovskytė S, A Budrienė (2024)

Ecological Speciation without Morphological Differentiation? A New Cryptic Species of Diodontus Curtis (Hymenoptera, Pemphredonidae) from the Centre of Europe.

Insects, 15(2): pii:insects15020086.

Upon exploring the mitotype diversity of the aphid-hunting wasp, Diodontus tristis, we revealed specimens with highly divergent mitotypes from two localities in Lithuania and nesting in clayey substrate, while the specimens with typical mitotypes were found nesting in sandy sites. The comparison of inter- and intra-specific distances and application of delimitation algorithms supported the species status of the clay-nesting populations. Using a set of DNA markers that included complete or partial sequences of six mitochondrial genes, three markers of ribosomal operon, two homeobox genes, and four other nuclear genes, we clarified the phylogenetic relationships of the new cryptic species. The endosymbiotic bacteria infestation was checked, considering the option that the divergent populations may represent clades isolated by Wolbachia infection; however, it did not demonstrate any specificity. We found only subtle morphological differences in the new clay-nesting species, D. argillicola sp. nov.; the discriminant analysis of morphometric measurements did not reliably segregate it as well. Thus, we provide the molecular characters of the cryptic species, which allow confident identification, its phylogenetic position within the genus, and an updated identification key for the D. tristis species group.

RevDate: 2024-02-23

Reese C, Graber LC, Ramalho MO, et al (2024)

The Diversity of Wolbachia across the Turtle Ants (Formicidae: Cephalotes spp.).

Biology, 13(2): pii:biology13020121.

Wolbachia is a widespread and well-known bacterium that can induce a wide range of changes within its host. Ants specifically harbor a great deal of Wolbachia diversity and are useful systems to study endosymbiosis. The turtle ants (Cephalotes) are a widespread group of tropical ants that rely on gut microbes to support their herbivorous diet for their survival, yet little is known of the extent of this diversity. Therefore, studying their endosymbionts and categorizing the diversity of bacteria within Cephalotes hosts could help to delimit species and identify new strains and can help lead to a further understanding of how the microbiome leads to survival and speciation in the wild. In our study, 116 individual samples were initially tested for positive infection with the wsp gene. Of the initial 116 samples, 9 samples were infected with only one strain of Wolbachia, and 7 were able to be used successfully for multilocus sequence typing (MLST). We used the new MLST data to infer a phylogeny with other Formicidae samples from the MLST online database to identify new Wolbachia strains and related genes, of which only one came back as an exact match. The 18 Wolbachia-positive samples ranged across 15 different species and 7 different countries, which we further test for species identity and geographic correlation. This study is the first comprehensive look into the diversity of Wolbachia in the turtle ants, providing insight into how endosymbionts are oriented in widespread species and providing a strong foundation for further research in host-microbe interactions.

RevDate: 2024-02-22

Ye QT, Gong X, Liu HH, et al (2024)

The symbiont Wolbachia alleviates pesticide susceptibility in the two-spotted spider mite Tetranychus urticae through enhanced host detoxification pathways.

Insect science [Epub ahead of print].

The two-spotted spider mite (Tetranychus urticae) is one of the most well-known pesticide-resistant agricultural pests, with resistance often attributed to changes such as target-site mutations and detoxification activation. Recent studies show that pesticide resistance can also be influenced by symbionts, but their involvement in this process in spider mites remains uncertain. Here, we found that infection with Wolbachia, a well-known bacterial reproductive manipulator, significantly increased mite survival after exposure to the insecticides abamectin, cyflumetofen, and pyridaben. Wolbachia-infected (WI) mites showed higher expression of detoxification genes such as P450, glutathione-S-transferase (GST), ABC transporters, and carboxyl/cholinesterases. RNA interference experiments confirmed the role of the two above-mentioned detoxification genes, TuCYP392D2 and TuGSTd05, in pesticide resistance. Increased GST activities were also observed in abamectin-treated WI mites. In addition, when wild populations were treated with abamectin, WI mites generally showed better survival than uninfected mites. However, genetically homogeneous mites with different Wolbachia strains showed similar survival. Finally, abamectin treatment increased Wolbachia abundance without altering the mite's bacterial community. This finding highlights the role of Wolbachia in orchestrating pesticide resistance by modulating host detoxification. By unraveling the intricate interplay between symbionts and pesticide resistance, our study lays the groundwork for pioneering strategies to combat agricultural pests.

RevDate: 2024-02-21

Mendoza-Roldan JA, Perles L, Filippi E, et al (2024)

Parasites and microorganisms associated with the snakes collected for the "festa Dei serpari" in Cocullo, Italy.

PLoS neglected tropical diseases, 18(2):e0011973 pii:PNTD-D-23-01442 [Epub ahead of print].

While in much of the Western world snakes are feared, in the small, rural, mountainous town of Cocullo, in the middle of central Italy, snakes are annually collected and celebrated in a sacro-profane ritual. Every 1st of May, Serpari (snake catchers) capture and showcase dozens of non-venomous snakes to celebrate the ritual of San Domenico. In order to detect potential zoonotic pathogens within this unique epidemiological context, parasites and microorganisms of snakes harvested for the "festa dei serpari" ritual was investigated. Snakes (n = 112) were examined and ectoparasites collected, as well as blood and feces sampled. Ectoparasites were identified morpho-molecularly, and coprological examination conducted through direct smear and flotation. Molecular screenings were performed to identify parasites and microorganisms in collected samples (i.e., Mesostigmata mites, Anaplasma/Ehrlichia spp., Rickettsia spp., Borrelia burgdorferi sensu lato, Coxiella burnetii, Babesia/Theileria spp., Cryptosporidium spp., Giardia spp., Leishmania spp. and helminths). Overall, 28.5% (32/112) of snakes were molecularly positive for at least one parasite and/or microorganism. Endosymbiont Wolbachia bacteria were identified from Macronyssidae mites and zoonotic vector-borne bacteria (e.g., Rickettsia, Leishmania), as well as orally transmitted pathogens (i.e., Cryptosporidium, Giardia, Proteus vulgaris, Pseudomonas), were detected from blood and feces. Thus, given the central role of the snakes in the tradition of Cocullo, surveys of their parasitic fauna and associated zoonotic pathogens may aid to generate conservation policies to benefit the human-snake interactions, whilst preserving the cultural patrimony of this event.

RevDate: 2024-02-21

Pramono AK, Hidayanti AK, Tagami Y, et al (2024)

Bacterial community and genome analysis of cytoplasmic incompatibility-inducing Wolbachia in American serpentine leafminer, Liriomyza trifolii.

Frontiers in microbiology, 15:1304401.

Liriomyza trifolii, an agricultural pest, is occasionally infected by Wolbachia. A Wolbachia strain present in Liriomyza trifolii is associated with cytoplasmic incompatibility (CI) effects, leading to the death of embryos resulting from incompatible crosses between antibiotic-treated or naturally Wolbachia-free strain females and Wolbachia-infected males. In this study, high-throughput sequencing of hypervariable rRNA genes was employed to characterize the bacterial community in Wolbachia-infected L. trifolii without antibiotic treatment. The analysis revealed that Wolbachia dominates the bacterial community in L. trifolii, with minor presence of Acinetobacter, Pseudomonas, and Limnobacter. To elucidate the genetic basis of the CI phenotype, metagenomic sequencing was also conducted to assemble the genome of the Wolbachia strain. The draft-genome of the Wolbachia strain wLtri was 1.35 Mbp with 34% GC content and contained 1,487 predicted genes. Notably, within the wLtri genome, there are three distinct types of cytoplasmic incompatibility factor (cif) genes: Type I, Type III, and Type V cifA;B. These genes are likely responsible for inducing the strong cytoplasmic incompatibility observed in L. trifolii.

RevDate: 2024-02-20

Mazel F, Pitteloud C, Guisan A, et al (2024)

Contrasted host specificity of gut and endosymbiont bacterial communities in alpine grasshoppers and crickets.

ISME communications, 4(1):ycad013.

Bacteria colonize the body of macroorganisms to form associations ranging from parasitic to mutualistic. Endosymbiont and gut symbiont communities are distinct microbiomes whose compositions are influenced by host ecology and evolution. Although the composition of horizontally acquired symbiont communities can correlate to host species identity (i.e. harbor host specificity) and host phylogeny (i.e. harbor phylosymbiosis), we hypothesize that the microbiota structure of vertically inherited symbionts (e.g. endosymbionts like Wolbachia) is more strongly associated with the host species identity and phylogeny than horizontally acquired symbionts (e.g. most gut symbionts). Here, using 16S metabarcoding on 336 guts from 24 orthopteran species (grasshoppers and crickets) in the Alps, we observed that microbiota correlated to host species identity, i.e. hosts from the same species had more similar microbiota than hosts from different species. This effect was ~5 times stronger for endosymbionts than for putative gut symbionts. Although elevation correlated with microbiome composition, we did not detect phylosymbiosis for endosymbionts and putative gut symbionts: closely related host species did not harbor more similar microbiota than distantly related species. Our findings indicate that gut microbiota of studied orthopteran species is more correlated to host identity and habitat than to the host phylogeny. The higher host specificity in endosymbionts corroborates the idea that-everything else being equal-vertically transmitted microbes harbor stronger host specificity signal, but the absence of phylosymbiosis suggests that host specificity changes quickly on evolutionary time scales.

RevDate: 2024-02-16

Hegde S, Marriott AE, Pionnier N, et al (2024)

Combinations of the azaquinazoline anti-Wolbachia agent, AWZ1066S, with benzimidazole anthelmintics synergise to mediate sub-seven-day sterilising and curative efficacies in experimental models of filariasis.

Frontiers in microbiology, 15:1346068.

Lymphatic filariasis and onchocerciasis are two major neglected tropical diseases that are responsible for causing severe disability in 50 million people worldwide, whilst veterinary filariasis (heartworm) is a potentially lethal parasitic infection of companion animals. There is an urgent need for safe, short-course curative (macrofilaricidal) drugs to eliminate these debilitating parasite infections. We investigated combination treatments of the novel anti-Wolbachia azaquinazoline small molecule, AWZ1066S, with benzimidazole drugs (albendazole or oxfendazole) in up to four different rodent filariasis infection models: Brugia malayi-CB.17 SCID mice, B. malayi-Mongolian gerbils, B. pahangi-Mongolian gerbils, and Litomosoides sigmodontis-Mongolian gerbils. Combination treatments synergised to elicit threshold (>90%) Wolbachia depletion from female worms in 5 days of treatment, using 2-fold lower dose-exposures of AWZ1066S than monotherapy. Short-course lowered dose AWZ1066S-albendazole combination treatments also delivered partial adulticidal activities and/or long-lasting inhibition of embryogenesis, resulting in complete transmission blockade in B. pahangi and L. sigmodontis gerbil models. We determined that short-course AWZ1066S-albendazole co-treatment significantly augmented the depletion of Wolbachia populations within both germline and hypodermal tissues of B. malayi female worms and in hypodermal tissues in male worms, indicating that anti-Wolbachia synergy is not limited to targeting female embryonic tissues. Our data provides pre-clinical proof-of-concept that sub-seven-day combinations of rapid-acting novel anti-Wolbachia agents with benzimidazole anthelmintics are a promising curative and transmission-blocking drug treatment strategy for filarial diseases of medical and veterinary importance.

RevDate: 2024-02-13

Yang K, Zhang HY, Wang P, et al (2023)

Both symbionts and environmental factors contribute to shape the microbiota in a pest insect, Sogatella furcifera.

Frontiers in microbiology, 14:1336345.

INTRODUCTION: Bacterial symbionts are prevalent in arthropods globally and play a vital role in the fitness and resistance of hosts. While several symbiont infections have been identified in the white-backed planthopper Sogatella furcifera, the impact of environmental factors on the microbiota within S. furcifera remains elusive.

METHODS: In this study, a total of 142 S. furcifera individuals from 18 populations were collected from 14 locations across six countries (China, Thailand, Myanmar, Cambodia, Vietnam, and Laos) analyzed with 2bRAD-M sequencing, to examine the effects of symbionts on the microbiota in the S. furcifera population, as well as the vital effects of environmental factors on the bacterial communities.

RESULTS AND DISCUSSION: Based on the results, in S. furcifera, the presence of symbionts Wolbachia and Cardinium negatively influenced the abundance of other bacteria, including Enterobacter, Acinetobacter, and Lysinibacillus, while Wolbachia infection significantly decreased the diversity of the microbial community. Moreover, several environmental factors, including longitude, latitude, temperature, and precipitation, affected the abundance of symbionts and microbiota diversity in S. furcifera. These results collectively highlight the vital role of Wolbachia in S. furcifera microbiota, as well as the intricate effects of environmental factors on the bacterial communities of S. furcifera.

RevDate: 2024-02-11

Lim JT, Bansal S, Chong CS, et al (2024)

Efficacy of Wolbachia-mediated sterility to reduce the incidence of dengue: a synthetic control study in Singapore.

The Lancet. Microbe pii:S2666-5247(23)00397-X [Epub ahead of print].

BACKGROUND: Due to the absence of available therapeutics and good vaccines, vector control solutions are needed to mitigate the spread of dengue. Matings between male Aedes aegypti mosquitoes infected with the wAlbB strain of Wolbachia and wildtype females yield non-viable eggs. We evaluated the efficacy of releasing wAlbB-infected A aegypti male mosquitoes to suppress dengue incidence.

METHODS: In this synthetic control study, we conducted large-scale field trials in Singapore involving release of wAlbB-infected A aegypti male mosquitoes for dengue control via vector population suppression, from epidemiological week (EW) 27, 2018, to EW 26, 2022. We selected two large towns (Yishun and Tampines) to adopt an expanding release strategy and two smaller towns (Bukit Batok and Choa Chu Kang) to adopt a targeted-release approach. Releases were conducted two times a week in high-rise public housing estates. All intervention and control locations practised the same baseline dengue control protocol. The main outcome was weekly dengue incidence rate caused by any dengue virus serotype. We used incidence data collected by the Singapore Ministry of Health to assess the efficacy of the interventions. To compare interventions, we used the synthetic control method to generate appropriate counterfactuals for the intervention towns using a weighted combination of 30 control towns between EW 1, 2014 and EW 26, 2022.

FINDINGS: Our study comprised an at-risk population of 607 872 individuals living in intervention sites and 3 894 544 individuals living in control sites. Interventions demonstrated up to 77·28% (121/156, 95% CI 75·81-78·58) intervention efficacy despite incomplete coverage across all towns until EW 26, 2022. Intervention efficacies increased as release coverage increased across all intervention sites. Releases led to 2242 (95% CI 2092-2391) fewer cases per 100 000 people in intervention sites during the study period. Secondary analysis showed that these intervention effects were replicated across all age groups and both sexes for intervention sites.

INTERPRETATION: Our results demonstrated the potential of Wolbachia-mediated incompatible insect technique for strengthening dengue control in tropical cities, where dengue burden is the greatest.

FUNDING: Singapore Ministry of Finance, Ministry of Sustainability, and the National Environment Agency, and the Singapore National Robotics Program.

RevDate: 2024-02-08

Hoffmann AA, Ahmad NW, Keong WM, et al (2024)

Introduction of Aedes aegypti mosquitoes carrying wAlbB Wolbachia sharply decreases dengue incidence in disease hotspots.

iScience, 27(2):108942 pii:S2589-0042(24)00163-9.

Partial replacement of resident Aedes aegypti mosquitoes with introduced mosquitoes carrying certain strains of inherited Wolbachia symbionts can result in transmission blocking of dengue and other viruses of public health importance. Wolbachia strain wAlbB is an effective transmission blocker and stable at high temperatures, making it particularly suitable for hot tropical climates. Following trial field releases in Malaysia, releases using wAlbB Ae. aegypti have become operationalized by the Malaysian health authorities. We report here on an average reduction in dengue fever of 62.4% (confidence intervals 50-71%) in 20 releases sites when compared to 76 control sites in high-rise residential areas. Importantly the level of dengue reduction increased with Wolbachia frequency, with 75.8% reduction (61-87%) estimated at 100% Wolbachia frequency. These findings indicate large impacts of wAlbB Wolbachia invasions on dengue fever incidence in an operational setting, with incidence expected to further decrease as wider areas are invaded.

RevDate: 2024-02-08

Liu Y, Zhao L, Qiu Z, et al (2023)

The gut microbiota diversity of five Orthoptera (Insecta, Polyneoptera) insects determined by DNA metabarcoding.

Biodiversity data journal, 11:e98162 pii:98162.

Most orthopteran insects are phytophagous and some are important pests in agriculture and forests. Many intestinal microflora of Orthoptera insects have been reported, primarily from Acridoidea and there have been few reports of other taxa. In this study, we collected 15 individuals representing five species (Ruspolialineosa, Tetrixjaponica, Erianthusversicolor, Gryllotalpaorientalis and Teleogryllusemma) belonging to five orthopteran superfamilies (Tettigonioidea, Tetrigoidea, Eumastacoidea, Gryllotalpoidea and Grylloidea) to characterise and compare the gut microbiota with greater taxonomic width by performing sequencing analysis of the 16S rRNA V4 region in gut material. A total of 606,053 high-quality sequences and 3,105 OTUs were acquired from 15 gut samples representing 24 phyla, 48 classes, 69 orders, 133 families and 219 genera. Firmicutes and bacteria were the most abundant phyla, followed by Bacteroidetes, Cyanobacteria, Actinobacteria and Acidobacteria. At the genus level, Serratia, Citrobacter, Wolbachia, Lactobacillus and Parabacteroides were the most predominant genera in R.lineosa, T.japonica, E.versicolor, G.orientalis and T.emma, respectively. Both Principal Coordinates Analysis (PCoA) and heatmap results revealed significant differences in bacterial community composition across species. Additionally, alpha diversity analysis indicated the bacterial richness was significantly different amongst the five species.

RevDate: 2024-02-05

Namias A, Ngaku A, Makoundou P, et al (2024)

Intra-lineage microevolution of Wolbachia leads to the emergence of new cytoplasmic incompatibility patterns.

PLoS biology, 22(2):e3002493 pii:PBIOLOGY-D-23-01655 [Epub ahead of print].

Mosquitoes of the Culex pipiens complex are worldwide vectors of arbovirus, filarial nematodes, and avian malaria agents. In these hosts, the endosymbiotic bacteria Wolbachia induce cytoplasmic incompatibility (CI), i.e., reduced embryo viability in so-called incompatible crosses. Wolbachia infecting Culex pipiens (wPip) cause CI patterns of unparalleled complexity, associated with the amplification and diversification of cidA and cidB genes, with up to 6 different gene copies described in a single wPip genome. In wPip, CI is thought to function as a toxin-antidote (TA) system where compatibility relies on having the right antidotes (CidA) in the female to bind and neutralize the male's toxins (CidB). By repeating crosses between Culex isofemale lines over a 17 years period, we documented the emergence of a new compatibility type in real time and linked it to a change in cid genes genotype. We showed that loss of specific cidA gene copies in some wPip genomes results in a loss of compatibility. More precisely, we found that this lost antidote had an original sequence at its binding interface, corresponding to the original sequence at the toxin's binding interface. We showed that these original cid variants are recombinant, supporting a role for recombination rather than point mutations in rapid CI evolution. These results strongly support the TA model in natura, adding to all previous data acquired with transgenes expression.

RevDate: 2024-01-31

Li JH, Liu XH, Liang GR, et al (2024)

Microplastics affect mosquito from aquatic to terrestrial lifestyles and are transferred to mammals through mosquito bites.

The Science of the total environment pii:S0048-9697(24)00684-3 [Epub ahead of print].

Microplastics (MPs) transfer from the environment to living organisms is a nonignorable global problem. As a complete metamorphosis insect, the larvae and adult Culex quinquefasciatus mosquito live in aquatic and terrestrial environments, respectively, where they easily access MPs. However, little is known about mosquitoes' potential role in MPs accumulation throughout ecosystems. Therefore, we conducted a study with different MPs particle sizes (0.1/1/10 μm) and concentrations (0.5/5/50 μg/mL) on Cx. quinquefasciatus to address this issue. Once exposed at the young larval stage, MPs could accompany the mosquitoes their entire life. The fluorescence signals of MPs in the larvae were mainly located in the intestines. Its intensity increased (from 3.72 × 10[6] AU to 5.45 × 10[7] AU) as the concentrations of MPs increases. The fluorescence signals of MPs were also detected in the blood and skin tissues of mice bitten by adult mosquitoes with MPs containing in their bodies. Mosquitos exposed to MPs showed longer larval pupation and eclosion time as well as lower adult body weight. In addition, MPs significantly reduced the lethal effect of pyrethroid insecticides (97.77 % vs. 48.88 %, p < 0.05) with 15.1 % removal of the deltamethrin concentration. After MPs exposure, the relative abundance of the Cx. quinquefasciatus gut microbiome, such as Wolbachia spp., Elizabethkingia spp., and Asaia spp., changed as the MPs size and concentration changes. Mosquitoes provide a new pathway for MPs accumulation and transfer to higher-level living organisms. Moreover, MPs significantly reduce the control effect of deltamethrin, providing new guidelines for mosquito insecticide application in MPs contamination circumstances.

RevDate: 2024-01-29

McNamara CJ, Ant TH, Harvey-Samuel T, et al (2024)

Transgenic expression of cif genes from Wolbachia strain wAlbB recapitulates cytoplasmic incompatibility in Aedes aegypti.

Nature communications, 15(1):869.

The endosymbiotic bacteria Wolbachia can invade insect populations by modifying host reproduction through cytoplasmic incompatibility (CI), an effect that results in embryonic lethality when Wolbachia-carrying males mate with Wolbachia-free females. Here we describe a transgenic system for recreating CI in the major arbovirus vector Aedes aegypti using CI factor (cif) genes from wAlbB, a Wolbachia strain currently being deployed to reduce dengue transmission. CI-like sterility is induced when cifA and cifB are co-expressed in testes; this sterility is rescued by maternal cifA expression, thereby reproducing the pattern of Wolbachia-induced CI. Expression of cifB alone is associated with extensive DNA damage and disrupted spermatogenesis. The strength of rescue by maternal cifA expression is dependent on the comparative levels of cifA/cifB expression in males. These findings are consistent with CifB acting as a toxin and CifA as an antitoxin, with CifA attenuating CifB toxicity in both the male germline and in developing embryos. These findings provide important insights into the interactions between cif genes and their mechanism of activity and provide a foundation for the building of a cif gene-based drive system in Ae. aegypti.

RevDate: 2024-01-26

Piccinno R, Tatti A, Avosani S, et al (2024)

A multidisciplinary approach to tackling invasive species: barcoding, morphology, and metataxonomy of the leafhopper Arboridia adanae.

Scientific reports, 14(1):2229.

The leafhopper genus Arboridia includes several species that feed on Vitis vinifera and cause leaf chlorosis. We report the first alien Arboridia infestation in Italy in 2021 in an Apulian vineyard. To confirm the taxonomic status of the species responsible for crop damage, and reconstruct its demographic history, we barcoded individuals from Apulia together with Arboridia spp. from Crete (Greece), A. adanae from Central Turkey and other specimens of the presumed sister species, A. dalmatina from Dalmatia (Croatia). Molecular phylogenies and barcoding gap analysis identified clades not associated with sampling locations. This result is incongruent with classical specimen assignment and is further supported by morphological analyses, which did not reveal significant differences among the populations. Therefore, we propose A. dalmatina as a junior synonym of A. adanae, which would become the only grapevine-related Arboridia species in the eastern Mediterranean. To further characterise A. adanae evolution, we performed a molecular clock analysis that suggested a radiation during the Pleistocene glaciations. Finally, to assess whether the Apulian individuals carried microorganisms of agricultural relevance, we sequenced their bacterial microbiota using 16S rRNA amplicon sequencing identifying three phytopathogens not generally associated with Arboridia activities as well as Wolbachia in one Apulian haplogroup. We discuss the agricultural implications of this infestation.

RevDate: 2024-01-23

Rainey SM, Lefteri DA, Darby C, et al (2024)

Evidence of Differences in Cellular Regulation of Wolbachia-Mediated Viral Inhibition between Alphaviruses and Flaviviruses.

Viruses, 16(1): pii:v16010115.

The intracellular bacterium Wolbachia is increasingly being utilised in control programs to limit the spread of arboviruses by Aedes mosquitoes. Achieving a better understanding of how Wolbachia strains can reduce viral replication/spread could be important for the long-term success of such programs. Previous studies have indicated that for some strains of Wolbachia, perturbations in lipid metabolism and cholesterol storage are vital in Wolbachia-mediated antiviral activity against the flaviviruses dengue and Zika; however, it has not yet been examined whether arboviruses in the alphavirus group are affected in the same way. Here, using the reporters for the alphavirus Semliki Forest virus (SFV) in Aedes albopictus cells, we found that Wolbachia strains wMel, wAu and wAlbB blocked viral replication/translation early in infection and that storage of cholesterol in lipid droplets is not key to this inhibition. Another alphavirus, o'nyong nyong virus (ONNV), was tested in both Aedes albopictus cells and in vivo in stable, transinfected Aedes aegypti mosquito lines. The strains wMel, wAu and wAlbB show strong antiviral activity against ONNV both in vitro and in vivo. Again, 2-hydroxypropyl-β-cyclodextrin (2HPCD) was not able to rescue ONNV replication in cell lines, suggesting that the release of stored cholesterol caused by wMel is not able to rescue blockage of ONNV. Taken together, this study shows that alphaviruses appear to be inhibited early in replication/translation and that there may be differences in how alphaviruses are inhibited by Wolbachia in comparison to flaviviruses.

RevDate: 2024-01-23

Cheng Z, Liu Q, X Huang (2024)

Partial Correspondence between Host Plant-Related Differentiation and Symbiotic Bacterial Community in a Polyphagous Insect.

Animals : an open access journal from MDPI, 14(2): pii:ani14020283.

Host plants play a vital role in insect population differentiation, while symbiotic associations between bacteria and insects are ubiquitous in nature. However, existing studies have given limited attention to the connection between host-related differentiation and symbiotic bacterial communities in phytophagous insects. In this study, we collected 58 samples of Aphis odinae from different host plants in southern China and constructed phylogenetic trees to investigate their differentiation in relation to host plants. We also selected aphid samples from the five most preferred host plants and analyzed their symbiotic bacterial composition using Illumina sequencing of the V3-V4 hypervariable region of the 16S rRNA gene. The phylogeny and symbiotic bacterial community structure of A. odinae populations on different host plants showed that samples from Triadica sebifera (Euphorbiaceae) had a consistent presence of Wolbachia as the predominant secondary symbiont and suggested the possibility of undergoing differentiation. Conversely, although differentiation was observed in samples from Rhus chinensis (Anacardiaceae), no consistent presence of predominant secondary symbionts was found. Additionally, the samples from Heptapleurum heptaphyllum (Araliaceae) consistently carried Serratia, but no host differentiation was evident. In summary, this study reveals a partial correspondence between symbiotic bacterial communities and host-related differentiation in A. odinae. The findings contribute to our understanding of the microevolutionary influencing the macroevolutionary relationships between bacterial symbionts and phytophagous insects. The identification of specific symbionts associated with host-related differentiation provides valuable insights into the intricate dynamics of insect-bacteria interactions.

RevDate: 2024-01-20

Sohail A, Anders KL, McGuinness SL, et al (2024)

The epidemiology of imported and locally-acquired dengue in Australia, 2012-2022.

Journal of travel medicine pii:7577676 [Epub ahead of print].

BACKGROUND: Dengue is the most important arboviral disease globally, and poses ongoing challenges for control including in non-endemic countries with competent mosquito vectors at risk of local transmission through imported cases. We examined recent epidemiological trends in imported and locally-acquired dengue in Australia, where the Wolbachia mosquito population replacement method was implemented throughout dengue-prone areas of northern Queensland between 2011-2019.

METHODS: We analysed dengue cases reported to the Australian National Notifiable Disease Surveillance System (NNDSS) between January 2012 and December 2022, and Australian traveller movement data.

RESULTS: Between 2012 and 2022, 13 343 dengue cases were reported in Australia (median 1466 annual cases); 12 568 cases (94.2%) were imported, 584 (4.4%) were locally acquired and 191 (1.4%) had no origin recorded. Locally-acquired cases decreased from a peak in 2013 (n = 236) to zero in 2021-2022. Annual incidence of imported dengue ranged from 8·29/100000 (n = 917 cases) to 22·10/100000 (n = 2203) annual traveller movements between 2012 and 2019, decreased in 2020 (6·74/100000 traveller movements; n = 191) and 2021 (3·32/100000 traveller movements; n = 10) during COVID-19-related border closures, then rose to 34·79/100000 traveller movements (n = 504) in 2022. Imported cases were primarily acquired in Southeast Asia (n = 9323; 74%), Southern and Central Asia (n = 1555; 12%) and Oceania (n = 1341; 11%). Indonesia (n = 5778; 46%) and Thailand (n = 1483; 12%) were top acquisition countries. DENV-2 (n = 2147; 42%) and DENV-1 (n = 1526; 30%) were predominant serotypes.

CONCLUSION: Our analysis highlights Australia's successful control of locally-acquired dengue with Wolbachia. Imported dengue trends reflect both Australian travel destinations and patterns and local epidemiology in endemic countries.

FUNDING: AS is supported by a National Health and Medical Research (NHMRC) Postgraduate Scholarship (grant number 2002792), SLM by NHMRC Investigator Grants (grant number 2017229), KL by a NHMRC Senior Research Fellowship (grant number 1155005), and KLA by the Welcome Trust (grant number 224459/Z/21/Z).

RevDate: 2024-01-19

Mantilla-Granados JS, Castellanos JE, ML Velandia-Romero (2023)

A tangled threesome: understanding arbovirus infection in Aedes spp. and the effect of the mosquito microbiota.

Frontiers in microbiology, 14:1287519.

Arboviral infections transmitted by Aedes spp. mosquitoes are a major threat to human health, particularly in tropical regions but are expanding to temperate regions. The ability of Aedes aegypti and Aedes albopictus to transmit multiple arboviruses involves a complex relationship between mosquitoes and the virus, with recent discoveries shedding light on it. Furthermore, this relationship is not solely between mosquitoes and arboviruses, but also involves the mosquito microbiome. Here, we aimed to construct a comprehensive review of the latest information about the arbovirus infection process in A. aegypti and A. albopictus, the source of mosquito microbiota, and its interaction with the arbovirus infection process, in terms of its implications for vectorial competence. First, we summarized studies showing a new mechanism for arbovirus infection at the cellular level, recently described innate immunological pathways, and the mechanism of adaptive response in mosquitoes. Second, we addressed the general sources of the Aedes mosquito microbiota (bacteria, fungi, and viruses) during their life cycle, and the geographical reports of the most common microbiota in adults mosquitoes. How the microbiota interacts directly or indirectly with arbovirus transmission, thereby modifying vectorial competence. We highlight the complexity of this tripartite relationship, influenced by intrinsic and extrinsic conditions at different geographical scales, with many gaps to fill and promising directions for developing strategies to control arbovirus transmission and to gain a better understanding of vectorial competence. The interactions between mosquitoes, arboviruses and their associated microbiota are yet to be investigated in depth.

RevDate: 2024-01-17

Nindrea RD (2024)

Wolbachia: New Hopes for the Prevention of Dengue Hemorrhagic Fever in Indonesia.

RevDate: 2024-01-12

Arai H, Watada M, D Kageyama (2024)

Two male-killing Wolbachia from Drosophila birauraia that are closely related but distinct in genome structure.

Royal Society open science, 11(1):231502.

Insects harbour diverse maternally inherited bacteria and viruses, some of which have evolved to kill the male progeny of their hosts (male killing: MK). The fly species Drosophila biauraria carries a maternally transmitted MK-inducing partiti-like virus, but it was unknown if it carries other MK-inducing endosymbionts. Here, we identified two male-killing Wolbachia strains (wBiau1 and wBiau2) from D. biauraria and compared their genomes to elucidate their evolutionary processes. The two strains were genetically closely related but had exceptionally different genome structures with considerable rearrangements compared with combinations of other Wolbachia strains. Despite substantial changes in the genome structure, the two Wolbachia strains did not experience gene losses that would disrupt the male-killing expression or persistence in the host population. The two Wolbachia-infected matrilines carried distinct mitochondrial haplotypes, suggesting that wBiau1 and wBiau2 have invaded D. biauraria independently and undergone considerable genome changes owing to unknown selective pressures in evolutionary history. This study demonstrated the presence of three male-killers from two distinct origins in one fly species and highlighted the diverse and rapid genome evolution of MK Wolbachia in the host.

RevDate: 2024-01-11
CmpDate: 2024-01-11

Côrtes N, Lira A, Prates-Syed W, et al (2023)

Integrated control strategies for dengue, Zika, and Chikungunya virus infections.

Frontiers in immunology, 14:1281667.

Arboviruses are a major threat to public health in tropical regions, encompassing over 534 distinct species, with 134 capable of causing diseases in humans. These viruses are transmitted through arthropod vectors that cause symptoms such as fever, headache, joint pains, and rash, in addition to more serious cases that can lead to death. Among the arboviruses, dengue virus stands out as the most prevalent, annually affecting approximately 16.2 million individuals solely in the Americas. Furthermore, the re-emergence of the Zika virus and the recurrent outbreaks of chikungunya in Africa, Asia, Europe, and the Americas, with one million cases reported annually, underscore the urgency of addressing this public health challenge. In this manuscript we discuss the epidemiology, viral structure, pathogenicity and integrated control strategies to combat arboviruses, and the most used tools, such as vaccines, monoclonal antibodies, treatment, etc., in addition to presenting future perspectives for the control of arboviruses. Currently, specific medications for treating arbovirus infections are lacking, and symptom management remains the primary approach. However, promising advancements have been made in certain treatments, such as Chloroquine, Niclosamide, and Isatin derivatives, which have demonstrated notable antiviral properties against these arboviruses in vitro and in vivo experiments. Additionally, various strategies within vector control approaches have shown significant promise in reducing arbovirus transmission rates. These encompass public education initiatives, targeted insecticide applications, and innovative approaches like manipulating mosquito bacterial symbionts, such as Wolbachia. In conclusion, combatting the global threat of arbovirus diseases needs a comprehensive approach integrating antiviral research, vaccination, and vector control. The continued efforts of research communities, alongside collaborative partnerships with public health authorities, are imperative to effectively address and mitigate the impact of these arboviral infections on public health worldwide.

RevDate: 2024-01-10

Mat Udin AS, Uni S, Rodrigues J, et al (2024)

Redescription, molecular characterisation and Wolbachia endosymbionts of Mansonella (Tupainema) dunni (Mullin & Orihel, 1972) (Spirurida: Onchocercidae) from the common treeshrew Tupaia glis Diard & Duvaucel (Mammalia: Scandentia) in Peninsular Malaysia.

Current research in parasitology & vector-borne diseases, 5:100154.

The genus Mansonella Faust, 1929 includes 29 species, mainly parasites of platyrrhine monkeys in South America and anthropoid apes in Africa. In Malaysia, Mansonella (Tupainema) dunni (Mullin & Orihel, 1972) was described from the common treeshrew Tupaia glis Diard & Duvaucel (Scandentia). In a recent classification of the genus Mansonella, seven subgenera were proposed, with M. (Tup.) dunni as a monotypic species in the subgenus Tupainema. In this study, we collected new material of M. (Tup.) dunni from common treeshrews in Peninsular Malaysia and redescribed the morphological features of this species. We found that M. (Tup.) dunni differs from M. (Cutifilaria) perforata Uni et al., 2004 from sika deer Cervus nippon (Cetartiodactyla) in Japan, with regards to morphological features and predilection sites in their respective hosts. Based on multi-locus sequence analyses, we examined the molecular phylogeny of M. (Tup.) dunni and its Wolbachia genotype. Species of the genus Mansonella grouped monophyletically in clade ONC5 and M. (Tup.) dunni was placed in the most derived position within this genus. Mansonella (Tup.) dunni was closely related to M. (M.) ozzardi (Manson, 1897) from humans in Central and South America, and most distant from M. (C.) perforata. The calculated p-distances between the cox1 gene sequences for M. (Tup.) dunni and its congeners were 13.09% for M. (M.) ozzardi and 15.6-16.15% for M. (C.) perforata. The molecular phylogeny of Mansonella spp. thus corroborates their morphological differences. We determined that M. (Tup.) dunni harbours Wolbachia endosymbionts of the supergroup F genotype, in keeping with all other Mansonella species screened to date.

RevDate: 2024-01-09

Strunov A, Schönherr C, M Kapun (2024)

Wolbachia effects on thermal preference of natural Drosophila melanogaster are influenced by host genetic background, Wolbachia type, and bacterial titer.

Environmental microbiology [Epub ahead of print].

Temperature plays a fundamental role in the fitness of all organisms. In particular, it strongly affects metabolism and reproduction in ectotherms that have limited physiological capabilities to regulate their body temperature. The influence of temperature variation on the physiology and behaviour of ectotherms is well studied but we still know little about the influence of symbiotic interactions on thermal preference (Tp) of the host. A growing number of studies focusing on the Wolbachia-Drosophila host-symbiont system found that Wolbachia can influence Tp in Drosophila laboratory strains. Here, we investigated the effect of Wolbachia on Tp in wild-type D. melanogaster flies recently collected from nature. Consistent with previous data, we found reduced Tp compared to an uninfected control in one of two fly strains infected with the wMelCS Wolbachia type. Additionally, we, for the first time, found that Wolbachia titer variation influences the thermal preference of the host fly. These data indicate that the interaction of Wolbachia and Drosophila resulting in behavioural variation is strongly influenced by the genetic background of the host and symbiont. More studies are needed to better understand the evolutionary significance of Tp variation influenced by Wolbachia in natural Drosophila populations.

RevDate: 2024-01-08
CmpDate: 2024-01-05

Volpe HXL, Carmo-Sousa M, Luvizotto RAG, et al (2024)

The greening-causing agent alters the behavioral and electrophysiological responses of the Asian citrus psyllid to a putative sex pheromone.

Scientific reports, 14(1):455.

The Asian Citrus Psyllid (ACP), Diaphorina citri, is a vector of the pathological bacterium Candidatus Liberibacter asiaticus (CLas), which causes the most devastating disease to the citrus industry worldwide, known as greening or huanglongbing (HLB). Earlier field tests with an acetic acid-based lure in greening-free, 'Valencia' citrus orange groves in California showed promising results. The same type of lures tested in São Paulo, Brazil, showed unsettling results. During the unsuccessful trials, we noticed a relatively large proportion of females in the field, ultimately leading us to test field-collected males and females for Wolbachia and CLas. The results showed high rates of Wolbachia and CLas infection in field populations. We then compared the olfactory responses of laboratory-raised, CLas-free, and CLas-infected males to acetic acid. As previously reported, CLas-uninfected males responded to acetic acid at 1 µg. Surprisingly, CLas-infected males required 50 × higher doses of the putative sex pheromone, thus explaining the failure to capture CLas-infected males in the field. CLas infection was also manifested in electrophysiological responses. Electroantennogram responses from CLas-infected ACP males were significantly higher than those obtained with uninfected males. To the best of our knowledge, this is the first report of a pathogen infection affecting a vector's response to a sex attractant.

RevDate: 2024-01-06
CmpDate: 2024-01-03

Muharromah AF, Reyes JIL, Kagia N, et al (2023)

Genome-wide detection of Wolbachia in natural Aedes aegypti populations using ddRAD-Seq.

Frontiers in cellular and infection microbiology, 13:1252656.

BACKGROUND: Wolbachia, an endosymbiotic bacterium, is globally used to control arboviruses because of its ability to block arboviral replication and manipulate the reproduction of Wolbachia host, Aedes aegypti. Polymerase chain reaction (PCR)-based Wolbachia detection has been recently reported from natural Ae. aegypti populations. However, due to the technical limitations of PCR, such as primer incompatibility, PCR-based assays are not sufficiently reliable or accurate. In this study, we examined double digestion restriction site-associated DNA sequencing (ddRAD-Seq) efficiency and limitations in Wolbachia detection and quantification in field-collected Ae. aegypti natural populations in Metro Manila, the Philippines, compared with PCR-based assays.

METHODS: A total of 217 individuals Ae. aegypti were collected from Metropolitan Manila, Philippines. We separated it into 14 populations consisting of 7 female and male populations. We constructed a library for pool ddRAD-Seq per population and also screened for Wolbachia by PCR assays using wsp and 16S rRNA. Wolbachia density per population were measured using RPS17 as the housekeeping gene.

RESULTS: From 146,239,637 sequence reads obtained, 26,299 and 43,778 reads were mapped across the entire Wolbachia genome (with the wAlbA and wAlbB strains, respectively), suggesting that ddRAD-Seq complements PCR assays and supports more reliable Wolbachia detection from a genome-wide perspective. The number of reads mapped to the Wolbachia genome per population positively correlated with the number of Wolbachia-infected individuals per population based on PCR assays and the relative density of Wolbachia in the Ae. aegypti populations based on qPCR, suggesting ddRAD-Seq-based semi-quantification of Wolbachia by ddRAD-Seq. Male Ae. aegypti exhibited more reads mapped to the Wolbachia genome than females, suggesting higher Wolbachia prevalence rates in their case. We detected 150 single nucleotide polymorphism loci across the Wolbachia genome, allowing for more accurate the detection of four strains: wPip, wRi, TRS of Brugia malayi, and wMel.

CONCLUSIONS: Taken together, our results demonstrate the feasibility of ddRAD-Seq-based Wolbachia detection from field-collected Ae. aegypti mosquitoes.

RevDate: 2024-01-06
CmpDate: 2024-01-03

PLOS Neglected Tropical Diseases Editors (2023)

Expression of Concern: A Potential Role for the Interaction of Wolbachia Surface Proteins with the Brugia malayi Glycolytic Enzymes and Cytoskeleton in Maintenance of Endosymbiosis.

PLoS neglected tropical diseases, 17(12):e0011860.

RevDate: 2023-12-25

Mouillaud T, Berger A, Buysse M, et al (2023)

Limited association between Wolbachia and Plasmodium falciparum infections in natural populations of the major malaria mosquito Anopheles moucheti.

Evolutionary applications, 16(12):1999-2006.

Since the discovery of natural malaria vector populations infected by the endosymbiont bacterium Wolbachia, a renewed interest has arisen for using this bacterium as an alternative for malaria control. Among naturally infected mosquitoes, Anopheles moucheti, a major malaria mosquito in Central Africa, exhibits one of the highest prevalences of Wolbachia infection. To better understand whether this maternally inherited bacterium could be used for malaria control, we investigated Wolbachia influence in An. moucheti populations naturally infected by the malaria parasite Plasmodium falciparum. To this end, we collected mosquitoes in a village from Cameroon, Central Africa, where this mosquito is the main malaria vector. We found that the prevalence of Wolbachia bacterium was almost fixed in the studied mosquito population, and was higher than previously recorded. We also quantified Wolbachia in whole mosquitoes and dissected abdomens, confirming that the bacterium is also elsewhere than in the abdomen, but at lower density. Finally, we analyzed the association of Wolbachia presence and density on P. falciparum infection. Wolbachia density was slightly higher in mosquitoes infected with the malaria parasite than in uninfected mosquitoes. However, we observed no correlation between the P. falciparum and Wolbachia densities. In conclusion, our study indicates that naturally occurring Wolbachia infection is not associated to P. falciparum development within An. moucheti mosquitoes.

RevDate: 2023-12-25
CmpDate: 2023-12-25

Gruntenko NE, Deryuzhenko MA, Andreenkova OV, et al (2023)

Drosophila melanogaster Transcriptome Response to Different Wolbachia Strains.

International journal of molecular sciences, 24(24):.

Wolbachia is a maternally inherited, intercellular bacterial symbiont of insects and some other invertebrates. Here, we investigated the effect of two different Wolbachia strains, differing in a large chromosomal inversion, on the differential expression of genes in D. melanogaster females. We revealed significant changes in the transcriptome of the infected flies compared to the uninfected ones, as well as in the transcriptome of flies infected with the Wolbachia strain, wMelPlus, compared to flies infected with the wMelCS[112] strain. We linked differentially expressed genes (DEGs) from two pairwise comparisons, "uninfected-wMelPlus-infected" and "uninfected-wMelCS[112]-infected", into two gene networks, in which the following functional groups were designated: "Proteolysis", "Carbohydrate transport and metabolism", "Oxidation-reduction process", "Embryogenesis", "Transmembrane transport", "Response to stress" and "Alkaline phosphatases". Our data emphasized similarities and differences between infections by different strains under study: a wMelPlus infection results in more than double the number of upregulated DEGs and half the number of downregulated DEGs compared to a wMelCS[112] infection. Thus, we demonstrated that Wolbachia made a significant contribution to differential expression of host genes and that the bacterial genotype plays a vital role in establishing the character of this contribution.

RevDate: 2023-12-22

Loterio RK, Monson EA, Templin R, et al (2023)

Antiviral Wolbachia strains associate with Aedes aegypti endoplasmic reticulum membranes and induce lipid droplet formation to restrict dengue virus replication.

mBio [Epub ahead of print].

Aedes aegypti transmits a range of important human pathogenic viruses like dengue. However, infection of Ae. aegypti with the insect endosymbiotic bacterium, Wolbachia, reduces the risk of mosquito to human viral transmission. Wolbachia is being utilized at field sites across more than 13 countries to reduce the incidence of viruses like dengue, but it is not well understood how Wolbachia induces its antiviral effects. To examine this at the subcellular level, we compared how different strains of Wolbachia with varying antiviral strengths associate with and modify host cell structures. Strongly antiviral strains were found to specifically associate with the host endoplasmic reticulum and induce striking impacts on host cell lipid droplets. Inhibiting Wolbachia-induced lipid redistribution partially restored dengue virus replication demonstrating this is a contributing role for Wolbachia's antiviral activity. These findings provide new insights into how antiviral Wolbachia strains associate with and modify Ae. aegypti host cells.

RevDate: 2023-12-24

Shapoval NA, Kir'yanov AV, Krupitsky AV, et al (2023)

Phylogeography of Two Enigmatic Sulphur Butterflies, Colias mongola Alphéraky, 1897 and Colias tamerlana Staudinger, 1897 (Lepidoptera, Pieridae), with Relations to Wolbachia Infection.

Insects, 14(12):.

The genus Colias Fabricius, 1807 includes numerous taxa and forms with uncertain status and taxonomic position. Among such taxa are Colias mongola Alphéraky, 1897 and Colias tamerlana Staudinger, 1897, interpreted in the literature either as conspecific forms, as subspecies of different but morphologically somewhat similar Colias species or as distinct species-level taxa. Based on mitochondrial and nuclear DNA markers, we reconstructed a phylogeographic pattern of the taxa in question. We recover and include in our analysis DNA barcodes of the century-old type specimens, the lectotype of C. tamerlana deposited in the Natural History Museum (Museum für Naturkunde), Berlin, Germany (ZMHU) and the paralectotype of C. tamerlana and the lectotype of C. mongola deposited in the Zoological Institute, Russian Academy of Sciences, St. Petersburg, Russia (ZISP). Our analysis grouped all specimens within four (HP_I-HP_IV) deeply divergent but geographically poorly structured clades which did not support nonconspecifity of C. mongola-C. tamerlana. We also show that all studied females of the widely distributed haplogroup HP_II were infected with a single Wolbachia strain belonging to the supergroup B, while the males of this haplogroup, as well as all other investigated specimens of both sexes, were not infected. Our data highlight the relevance of large-scale sampling dataset analysis and the need for testing for Wolbachia infection to avoid erroneous phylogenetic reconstructions and species misidentification.

RevDate: 2023-12-24

Adonyeva NV, Efimov VM, NE Gruntenko (2023)

The Effect of Genotype Combinations of Wolbachia and Its Drosophila melanogaster Host on Fertility, Developmental Rate and Heat Stress Resistance of Flies.

Insects, 14(12):.

The best-known effect of the intracellular bacterium Wolbachia is its mostly negative influence on the reproduction of the host. However, there is evidence of a positive influence of Wolbachia on the host's resistance to stress, pathogens, and viruses. Here, we analyzed the effects of two Wolbachia strains belonging to wMel and wMelCS genotypes on D. melanogaster traits, such as fertility, survival under acute heat stress, and developmental rate. We found that D. melanogaster lines under study differ significantly in the above-mentioned characteristics, both when the natural infection was preserved, and when it was eliminated. One of Wolbachia strains, wMel, did not affect any of the studied traits. Another strain, wMelPlus, had a significant effect on the development time. Moreover, this effect is observed not only in the line in which it was discovered but also in the one it was transferred to. When transferred to a new line, wMelPlus also caused changes in survival under heat stress. Thus, it could be concluded that Wolbachia-Drosophila interaction depends on the genotypes of both the host and the symbiont, but some Wolbachia effects could depend not on the genotypes, but on the fact of recent transfer of the symbiont.

RevDate: 2023-12-24

Zadra N, Tatti A, Silverj A, et al (2023)

Shallow Whole-Genome Sequencing of Aedes japonicus and Aedes koreicus from Italy and an Updated Picture of Their Evolution Based on Mitogenomics and Barcoding.

Insects, 14(12):.

Aedes japonicus and Aedes koreicus are two invasive mosquitoes native to East Asia that are quickly establishing in temperate regions of Europe. Both species are vectors of arboviruses, but we currently lack a clear understanding of their evolution. Here, we present new short-read, shallow genome sequencing of A. japonicus and A. koreicus individuals from northern Italy, which we used for downstream phylogenetic and barcode analyses. We explored associated microbial DNA and found high occurrences of Delftia bacteria in both samples, but neither Asaia nor Wolbachia. We then assembled complete mitogenomes and used these data to infer divergence times estimating the split of A. japonicus from A. koreicus in the Oligocene, which was more recent than that previously reported using mitochondrial markers. We recover a younger age for most other nodes within Aedini and other Culicidae. COI barcoding and phylogenetic analyses indicate that A. japonicus yaeyamensis, A. japonicus amamiensis, and the two A. koreicus sampled from Europe should be considered as separate species within a monophyletic species complex. Our studies further clarify the evolution of A. japonicus and A. koreicus, and indicate the need to obtain whole-genome data from putative species in order to disentangle their complex patterns of evolution.

RevDate: 2023-12-22

Lin YJ, Yeh CH, Wu CZ, et al (2023)

Climate and Wolbachia Impacts on Anoplolepis gracilipes (Hymenoptera: Formicidae).

Biology, 12(12): pii:biology12121482.

The yellow crazy ant (Anoplolepis gracilipes (Smith, 1857)) is a prominent invasive species exhibiting variable population dynamics. Through collecting long-term climate data and validating field surveys with MaxEnt SDM projections, our results indicated that winter temperature and precipitation accumulation strongly influence the population dynamics. An aggression analysis showed that A. gracilipes nests with higher aggression levels (over 2.5 scores) experienced a higher mean maximum temperature (31.84 ± 0.43 °C) and lower prevalence of wAgra (84.8 ± 4.70%) in A. gracilipes from June to October. The nest manipulation and aggression experiments confirmed that temperature increases aggression (1.3 to 2.8 scores) among A. gracilipes workers due to the reduced prevalence of wAgra. To the best of our knowledge, this is the first case of a notable reduction in the prevalence of Wolbachia (100 to 66%) within a colony of A. gracilipes while maintaining stable nests for further experiments.

RevDate: 2023-12-22

Ochieng FO (2024)

SEIRS model for malaria transmission dynamics incorporating seasonality and awareness campaign.

Infectious Disease Modelling, 9(1):84-102.

Malaria, a devastating disease caused by the Plasmodium parasite and transmitted through the bites of female Anopheles mosquitoes, remains a significant public health concern, claiming over 600,000 lives annually, predominantly among children. Novel tools, including the application of Wolbachia, are being developed to combat malaria-transmitting mosquitoes. This study presents a modified susceptible-exposed-infectious-recovered-susceptible (SEIRS) compartmental mathematical model to evaluate the impact of awareness-based control measures on malaria transmission dynamics, incorporating mosquito interactions and seasonality. Employing the next-generation matrix approach, we calculated a basic reproduction number (R0) of 2.4537, indicating that without robust control measures, the disease will persist in the human population. The model equations were solved numerically using fourth and fifth-order Runge-Kutta methods. The model was fitted to malaria incidence data from Kenya spanning 2000 to 2021 using least squares curve fitting. The fitting algorithm yielded a mean absolute error (MAE) of 2.6463 when comparing the actual data points to the simulated values of infectious human population (Ih). This finding indicates that the proposed mathematical model closely aligns with the recorded malaria incidence data. The optimal values of the model parameters were estimated from the fitting algorithm, and future malaria dynamics were projected for the next decade. The research findings suggest that social media-based awareness campaigns, coupled with specific optimization control measures and effective management methods, offer the most cost-effective approach to managing malaria.

RevDate: 2023-12-28

Shropshire JD, Conner WR, Vanderpool D, et al (2023)

Rapid turnover of pathogen-blocking Wolbachia and their incompatibility loci.

bioRxiv : the preprint server for biology.

At least half of all insect species carry maternally inherited Wolbachia alphaproteobacteria, making Wolbachia the most common endosymbionts in nature. Wolbachia spread to high frequencies is often due to cytoplasmic incompatibility (CI), a Wolbachia-induced sperm modification that kills embryos without Wolbachia. Several CI-causing Wolbachia variants, including wMel from Drosophila melanogaster, also block viruses. Establishing pathogen-blocking wMel in natural Aedes aegypti mosquito populations has reduced dengue disease incidence, with one study reporting about 85% reduction when wMel frequency is high. However, wMel transinfection establishment is challenging in many environments, highlighting the importance of identifying CI-causing Wolbachia variants that stably persist in diverse hosts and habitats. We demonstrate that wMel-like variants have naturally established in widely distributed holometabolous dipteran and hymenopteran insects that diverged approximately 350 million years ago, with wMel variants spreading rapidly among these hosts over only the last 100,000 years. Wolbachia genomes contain prophages that encode CI-causing operons (cifs). These cifs move among Wolbachia genomes - with and without prophages - even more rapidly than Wolbachia move among insect hosts. Our results shed light on how rapid host switching and horizontal gene transfer contribute to Wolbachia and cif diversity in nature. The diverse wMel variants we report here from hosts present in different climates offer many new options for broadening Wolbachia-based biocontrol of diseases and pests.

RevDate: 2023-12-19
CmpDate: 2023-12-19

Cain JL, Norris JK, Swan MP, et al (2023)

A diverse microbial community and common core microbiota associated with the gonad of female Parascaris spp.

Parasitology research, 123(1):56.

The microbiome plays an important role in health, where changes in microbiota composition can have significant downstream effects within the host, and host-microbiota relationships can be exploited to affect health outcomes. Parasitic helminths affect animals globally, but an exploration of their microbiota has been limited, despite the development of anti-Wolbachia drugs to help control infections with some filarial nematodes. The equine ascarids, Parascaris spp., are considered the most pathogenic nematodes affecting juvenile horses and are also the only ascarid parasite to have developed widespread anthelmintic resistance. The aim of this study was to characterize the microbiota of this helminth, focusing on the female gonad, determine a core microbiota for this organ, identify bacterial species, and show bacterial localization to the female gonad via in situ hybridization (ISH). A total of 22 gonads were isolated from female Parascaris spp. collected from three foals, and 9 female parasites were formalin-fixed and paraffin-embedded for ISH. Next-generation sequencing was performed using V3-V4 primers as well as the Swift Amplicon™ 16S+ ITS Panel. Overall, ten genera were identified as members of the Parascaris spp. female gonad and twelve bacterial species were identified. The most prevalent genus was Mycoplasma, followed by Reyranella, and there were no differences in alpha diversity between parasites from different horses. Specific eubacteria staining was identified in both the intestine and within the gonad using ISH. Overall, this study provided in-depth information regarding the female Parascaris spp. microbiota and was the first to identify the core microbiota within a specific parasite organ.

RevDate: 2023-12-25
CmpDate: 2023-12-25

Lau DC, Power RI, J Šlapeta (2024)

Exploring multiplex qPCR as a diagnostic tool for detecting microfilarial DNA in dogs infected with Dirofilaria immitis: A comparative analysis with the modified Knott's test.

Veterinary parasitology, 325:110097.

Current recommendations to diagnose cardiopulmonary dirofilariosis in dogs caused by Dirofilaria immitis involves tandem antigen and circulating microfilariae tests. The modified Knott's test is an important tool in heartworm diagnosis, allowing identification of circulating microfilariae. However, the subjective nature of the modified Knott's test affects its accuracy and diagnostic laboratories usually do not provide a quantitative outcome. Quantitative enumeration of microfilariae enables clinicians to track treatment progress and acts as a proxy for detecting emerging macrocyclic lactone resistance. There is a need for better diagnostic tools suitable for routine use to efficiently and accurately quantify the presence of D. immitis microfilaremia. The aim of this study was to determine whether the quantitative modified Knott's test can be substituted by multiplex quantitative polymerase chain reaction (qPCR) targeting D. immitis and associated Wolbachia endosymbiont DNA in canine blood samples. To do this, genomic DNA samples (n = 161) from Australian dogs, collected as part of a previous 2021 study, were assessed in a TaqMan qPCR targeting DNA of D. immitis, Wolbachia sp. and Canis lupus familiaris. Of the 161 genomic DNA samples, eight were considered positive for D. immitis microfilariae. The qPCR assay demonstrated good efficiency (E = 90 to 110%, R[2] > 0.94). Considering the performance and efficient use of bench time, this TaqMan qPCR assay is a suitable alternative to the modified Knott's test for quantitative enumeration of microfilariae (Cohen's kappa coefficient [κ]: κ = 1 using D. immitis qPCR marker, κ = 0.93 using Wolbachia qPCR marker). The qPCR data demonstrated a comparable result to that of the quantitative modified Knott's test in a 2022 survey of D. immitis in Australian dogs (n = 23) before and after macrocyclic lactone (ML) administration. Improving the detection and diagnosis of canine heartworm infections will assist veterinarians in better managing and controlling disease outcomes and will be valuable for tracking the spread of ML resistance in Australia.

RevDate: 2023-12-17

Malavige GN, Sjö P, Singh K, et al (2023)

Facing the escalating burden of dengue: Challenges and perspectives.

PLOS global public health, 3(12):e0002598.

Dengue is the most rapidly emerging mosquito-borne infection and, due to climate change and unplanned urbanization, it is predicted that the global burden of dengue will rise further as the infection spreads to new geographical locations. Dengue-endemic countries are often unable to cope with such increases, with health care facilities becoming overwhelmed during each dengue season. Furthermore, although dengue has been predominantly a childhood illness in the past, it currently mostly affects adults in many countries, with higher incidence of severe disease and mortality rates in pregnant women and in those with comorbidities. As there is currently no specific treatment for dengue and no early biomarker to identify those who will progress to develop vascular leakage, all individuals with dengue are closely monitored in case they need fluid management. Furthermore, diagnosing patients with acute dengue is challenging due to the similarity of clinical symptoms during early illness and poor sensitivity and specificity of point-of-care diagnostic tests. Novel vector control methods, such as the release of Wolbachia-infected mosquitoes, have shown promising results by reducing vector density and dengue incidence in clinical trial settings. A new dengue vaccine, TAK-003, had an efficacy of 61.2% against virologically confirmed dengue, 84.1% efficacy against hospitalizations and a 70% efficacy against development of dengue haemorrhagic fever (DHF) at 54 months. While vaccines and mosquito control methods are welcome, they alone are unlikely to fully reduce the burden of dengue, and a treatment for dengue is therefore essential. Several novel antiviral drugs are currently being evaluated along with drugs that inhibit host mediators, such as mast cell products. Although viral proteins such as NS1 contribute to the vascular leak observed in severe dengue, the host immune response to the viral infection also plays a significant role in progression to severe disease. There is an urgent need to discover safe and effective treatments for dengue to prevent disease progression.

RevDate: 2023-12-18

Fricke LC, AR Lindsey (2023)

Identification of parthenogenesis-inducing effector proteins in Wolbachia.

bioRxiv : the preprint server for biology.

Bacteria in the genus Wolbachia have evolved numerous strategies to manipulate arthropod sex, including the conversion of would-be male offspring to asexually reproducing females. This so-called "parthenogenesis-induction" phenotype can be found in a number of Wolbachia strains that infect arthropods with haplodiploid sex determination systems, including parasitoid wasps. Despite the discovery of microbe-mediated parthenogenesis more than 30 years ago, the underlying genetic mechanisms have remained elusive. We used a suite of genomic, computational, and molecular tools to identify and characterize two proteins that are uniquely found in parthenogenesis-inducing Wolbachia and have strong signatures of host-associated bacterial effector proteins. These putative parthenogenesis-inducing proteins have structural homology to eukaryotic protein domains including nucleoporins, the key insect sex-determining factor Transformer, and a eukaryotic-like serine-threonine kinase with leucine rich repeats. Furthermore, these proteins significantly impact eukaryotic cell biology in the model, Saccharomyces cerevisiae. We suggest these proteins are parthenogenesis-inducing factors and our results indicate this would be made possible by a novel mechanism of bacterial-host interaction.

RevDate: 2023-12-10

Urairi C, S Fujito (2023)

Interbiotype hybridization between biotypes A and B of Liriomyza chinensis (Diptera: Agromyzidae).

Journal of economic entomology pii:7468523 [Epub ahead of print].

Liriomyza chinensis (Kato) is a formidable pest of Allium species, especially the Japanese bunching onion Allium fistulosum L. Recently, a novel biotype of L. chinensis (biotype B) has emerged, which causes more severe damage than the native biotype A. It has been reported that biotype B has frequently displaced biotype A in the Japanese bunching onion fields in Japan. As interbiotype hybridization is a possible factor that influences such displacement, interbiotype hybridization was conducted between L. chinensis biotypes A and B. Eggs were not laid under one-by-one crossing conditions; however, adult hybrid progeny of both sexes emerged from no-choice mating combinations-when multiple males and females were present. The fertility of F1 hybrid adults was also investigated, and backcrossed adults emerged from F1 females in both mating combinations. F1 males might have exhibited reproductive abnormalities because only a small number of backcross progeny emerged from the mating combinations using F1 males. Additionally, 3 representative endosymbionts (Wolbachia, Spiroplasma, and Cardinium) were investigated, and both biotypes were found to be infected by the same strain of Wolbachia. In addition, the courtship signals (tapping) of male adults differed between biotypes A and B as well as between F1 hybrids; the F1 males exhibited tapping behavior that was intermediate between biotypes A and B. Therefore, mating sounds serve as a form of premating reproductive isolation between biotypes A and B.

RevDate: 2023-12-09

Arai H, Ueda M, Hirano T, et al (2023)

Conserved infections and reproductive phenotypes of Wolbachia symbionts in Asian tortrix moths.

Environmental microbiology reports [Epub ahead of print].

Wolbachia is a ubiquitous endosymbiotic bacterium that manipulates insect reproduction. A notable feature of Wolbachia is male killing (MK), whereby sons of infected females are killed during development; however, the evolutionary processes by which Wolbachia acquired the MK ability remain unclear. The tea tortrix moth Homona magnanima (Tortricidae) harbours three non-MK Wolbachia strains (wHm-a, wHm-b and wHm-c) and an MK strain wHm-t. Although wHm-t and wHm-c are closely related, only wHm-t has an MK-associated prophage region. To understand the evolutionary processes underlying the emergence of MK wHm-t, we examined Wolbachia infections and phenotypes in 62 tortricid species collected from 39 localities across Japan, Taiwan, Vietnam and Indonesia. PCR assays detected wHm-c relatives in 51 species and triple infection of wHm-a, wHm-b and wHm-c in 31 species. Apart from Taiwanese H. magnanima, no species exhibited the MK phenotype and were positive for the wHm-t-specific prophage. While wHm-t infection was dominant in Taiwanese H. magnanima, wHm-a, wHm-b and wHm-c were dominant in Japanese H. magnanima populations. These results suggest that wHm-a, wHm-b and wHm-c strains descended from a common ancestor with repeated infection loss and that wHm-t evolved from the wHm-c acquiring MK ability in allopatric populations of H. magnanima.

RevDate: 2023-12-16
CmpDate: 2023-12-16

Valdez-Delgado KM, Ríos-Delgado JC, Nettel-Cruz JA, et al (2023)

Aerial release of Aedes aegypti male mosquitoes using an unmanned aerial vehicle: a novel control strategy.

Salud publica de Mexico, 65(4, jul-ago):387-393.

OBJECTIVE: To development of a methodology for the chilling, handling, transport, and release of male Aedes aegypti mosquitoes, reared in insectary conditions to release in the field with unmanned vehicles to compete sexually with wild males in the field.

MATERIALS AND METHODS: A population of Ae. aegypti from different areas in Tapachula, Chiapas, was used. Laboratory tests were conducted: Effect of temperature and cooling time on the knockdown, recovery of males, and copulatory success.

RESULTS: The chilling temperature of 3 ± 1ºC for 30 min, was used as a knockdown temperature before handling, packing, transportation, and aerial release. The males subjected to the entire process, including the semi-field aerial release test, showed normal sexual behavior activity, obtaining 100% of females inseminated.

CONCLUSION: These results present the feasibility of applying a new control methodology using unmanned aerial vehicle (UAV) as support for the sterile insect release technique (SIT), use of Wolbachia or both, in male Ae. aegypti, for the design of strategies to control their populations.

RevDate: 2023-12-17
CmpDate: 2023-12-16

López-Ordóñez T, Díaz-Rodarte KI, Torres-Monzón JA, et al (2023)

[Not Available].

Salud publica de Mexico, 65(2 mar-abr):136-143.

OBJETIVO: Analizar la expresión diferencial de proteínas de Aedes aegypti infectados con Wolbachia y su asociación con el ciclo viral del virus dengue (DENV). Material y métodos. Se revisó una base de datos de proteínas de Ae. aegypti infec-tados y no infectados con Wolbachia, cepa wMel y se buscaron estas en revistas indizadas, que hablaran de la proteína y el ciclo viral de DENV.

RESULTADOS: La expresión diferencial de proteínas de los mosquitos durante la infección con Wolbachia intervienen en los procesos de entrada, replicación y salida del DENV.

CONCLUSIONES: Existen cambios en la expresión de proteínas de células infectadas con Wolbachia, que son necesarias para el ciclo de replicación de DENV, explicando porque algunos mosquitos infectados con Wolbachia son refractarios a la infección por DENV.

RevDate: 2023-12-07
CmpDate: 2023-12-07

Liu Z, T Zhou (2023)

The effect of migration on transmission of Wolbachia in Nilaparvata lugens.

Mathematical biosciences and engineering : MBE, 20(11):20213-20244.

Brown planthopper Nilaparvata lugens, which can transmit rice ragged stunt virus, is a serious and damaging pest to rice plants. Rice plants can protect themselves from the associated diseases of N.lugens by either suppressing or replacing N.lugens by releasing N.lugens infected by a special strain of Wolbachia wStri. The long-distance migration habit of N.lugens is one of the important precursors leading up to the large-scale occurrence of N.lugens. To study the effect of migration on the transmission of Wolbachia in N.lugens, a Wolbachia spreading dynamics model with migration of N.lugens between two patches is put forward. The existence and local stability conditions of equilibrium points of the system and its subsystems are obtained. Moreover, the effects of migration on the dynamic properties and the control of N.lugens are analyzed; the results show that the system can exhibit a bistable phenomenon, and the migration can change the stability of equilibrium infected with wStri from stable to unstable. The quantitative control methods for the migration of the insect N.lugens are proposed, which provide a theoretical guidance for future field experiments. Lastly, we use the Markov chain Monte Carlo (MCMC) method to estimate the parameters of the wild N.lugens migration model based on limited observational data; the numerical simulation results show that migration can increase the quantity of N.lugens, which is consistent with the relevant experimental results.

RevDate: 2024-01-15
CmpDate: 2024-01-15

Nakabachi A, T Suzaki (2024)

Ultrastructure of the bacteriome and bacterial symbionts in the Asian citrus psyllid, Diaphorina citri.

Microbiology spectrum, 12(1):e0224923.

Omics analyses suggested a mutually indispensable tripartite association among the host D. citri and organelle-like bacteriome associates, Carsonella and Profftella, which are vertically transmitted through host generations. This relationship is based on the metabolic complementarity among these organisms, which is partly enabled by horizontal gene transfer between partners. However, little was known about the fine morphology of the symbionts and the bacteriome, the interface among these organisms. As a first step to address this issue, the present study performed transmission electron microscopy, which revealed previously unrecognized ultrastructures, including aggregations of ribosomes in Carsonella, numerous tubes and occasional protrusions of Profftella, apparently degrading Profftella, and host organelles with different abundance and morphology in distinct cell types. These findings provide insights into the behaviors of the symbionts and host cells to maintain the symbiotic relationship in D. citri.

RevDate: 2023-12-16
CmpDate: 2023-12-04

Lühken R, Brattig N, N Becker (2023)

Introduction of invasive mosquito species into Europe and prospects for arbovirus transmission and vector control in an era of globalization.

Infectious diseases of poverty, 12(1):109.

BACKGROUND: Mosquito research in Europe has a long history, primarily focused on malaria vectors. In recent years, invasive mosquito species like the Asian tiger mosquito (Aedes albopictus) and the spread of arboviruses like dengue virus, chikungunya virus or bluetongue virus have led to an intensification of research and monitoring in Europe. The risk of further dissemination of exotic species and mosquito-borne pathogens is expected to increase with ongoing globalization, human mobility, transport geography, and climate warming. Researchers have conducted various studies to understand the ecology, biology, and effective control strategies of mosquitoes and associated pathogens.

MAIN BODY: Three invasive mosquito species are established in Europe: Asian tiger mosquito (Aedes albopictus), Japanese bush mosquito (Ae. japonicus), and Korean bush mosquito (Aedes koreicus). Ae. albopictus is the most invasive species and has been established in Europe since 1990. Over the past two decades, there has been an increasing number of outbreaks of infections by mosquito-borne viruses in particular chikungunya virus, dengue virus or Zika virus in Europe primary driven by Ae. albopictus. At the same time, climate change with rising temperatures results in increasing threat of invasive mosquito-borne viruses, in particular Usutu virus and West Nile virus transmitted by native Culex mosquito species. Effective mosquito control programs require a high level of community participation, going along with comprehensive information campaigns, to ensure source reduction and successful control. Control strategies for container breeding mosquitoes like Ae. albopictus or Culex species involve community participation, door-to-door control activities in private areas. Further measures can involve integration of sterile insect techniques, applying indigenous copepods, Wolbachia sp. bacteria, or genetically modified mosquitoes, which is very unlike to be practiced as standard method in the near future.

CONCLUSIONS: Climate change and globalization resulting in the increased establishment of invasive mosquitoes in particular of the Asian tiger mosquito Ae. albopictus in Europe within the last 30 years and increasing outbreaks of infections by mosquito-borne viruses warrants intensification of research and monitoring. Further, effective future mosquito control programs require increase in intense community and private participation, applying physical, chemical, biological, and genetical control activities.

RevDate: 2023-12-16
CmpDate: 2023-12-16

Ngnindji-Youdje Y, Lontsi-Demano M, Diarra AZ, et al (2024)

Morphological, molecular, and MALDI-TOF MS identification of bed bugs and associated Wolbachia species from Cameroon.

Acta tropica, 249:107086.

After vanishing from the public eye for more than 50 years, bed bugs have resurged to become one of the most widely discussed and heavily researched insect pests in the world. This study presents the basic information of infestations of tropical bed bugs, Cimex hemipterus (Hemiptera: Cimicidae), in Cameroon. A total of 248 immature stage and adult bed bug specimens were collected from households and a travel agency in Yaoundé and Douala, Cameroon. The ability of MALDI-TOF MS to identify bed bugs was tested using heads for adults and cephalothoraxes for immature stages. Microorganism screening was performed by qPCR and confirmed by regular PCR and sequencing. Based on morphometrical criteria, four stages of immature bed bugs are represented. Of the 248 bed bug specimens morphologically identified as Cimex hemipterus, 246 (77 males, 65 females and 104 immature specimens) were submitted to MALDI-TOF MS analysis. Of the 222 adults and immature specimens tested, 122 (59.9 %) produced good quality MALDI-TOF MS spectra (35 adults and 87 immature specimens). Blind testing allowed species level identification of 98.21 % of adult and immature C. hemipterus. Among the bacteria tested, only Wolbachia DNA was found in 12/246 (4.8 %) bed bugs. More surveys in the country are warranted to assess the true level of bed bug infestations, in order to take appropriate action for their control.

RevDate: 2023-12-17
CmpDate: 2023-12-04

Velez ID, Tanamas SK, Arbelaez MP, et al (2023)

Reduced dengue incidence following city-wide wMel Wolbachia mosquito releases throughout three Colombian cities: Interrupted time series analysis and a prospective case-control study.

PLoS neglected tropical diseases, 17(11):e0011713.

BACKGROUND: The introduction of Wolbachia (wMel strain) into Aedes aegypti mosquitoes reduces their capacity to transmit dengue and other arboviruses. Randomised and non-randomised studies in multiple countries have shown significant reductions in dengue incidence following field releases of wMel-infected Ae. aegypti. We report the public health outcomes from phased, large-scale releases of wMel-Ae. aegypti mosquitoes throughout three contiguous cities in the Aburrá Valley, Colombia.

Following pilot releases in 2015-2016, staged city-wide wMel-Ae. aegypti deployments were undertaken in the cities of Bello, Medellín and Itagüí (3.3 million people) between October 2016 and April 2022. The impact of the Wolbachia intervention on dengue incidence was evaluated in two parallel studies. A quasi-experimental study using interrupted time series analysis showed notified dengue case incidence was reduced by 95% in Bello and Medellín and 97% in Itagüí, following establishment of wMel at ≥60% prevalence, compared to the pre-intervention period and after adjusting for seasonal trends. A concurrent clinic-based case-control study with a test-negative design was unable to attain the target sample size of 63 enrolled virologically-confirmed dengue (VCD) cases between May 2019 and December 2021, consistent with low dengue incidence throughout the Aburrá Valley following wMel deployments. Nevertheless, VCD incidence was 45% lower (OR 0.55 [95% CI 0.25, 1.17]) and combined VCD/presumptive dengue incidence was 47% lower (OR 0.53 [95% CI 0.30, 0.93]) among participants resident in wMel-treated versus untreated neighbourhoods.

CONCLUSIONS/SIGNIFICANCE: Stable introduction of wMel into local Ae. aegypti populations was associated with a significant and sustained reduction in dengue incidence across three Colombian cities. These results from the largest contiguous Wolbachia releases to-date demonstrate the real-world effectiveness of the method across large urban populations and, alongside previously published results, support the reproducibility of this effectiveness across different ecological settings.

TRIAL REGISTRATION: NCT03631719.

RevDate: 2023-12-04
CmpDate: 2023-12-04

Velez ID, Uribe A, Barajas J, et al (2023)

Large-scale releases and establishment of wMel Wolbachia in Aedes aegypti mosquitoes throughout the Cities of Bello, Medellín and Itagüí, Colombia.

PLoS neglected tropical diseases, 17(11):e0011642.

BACKGROUND: The wMel strain of Wolbachia has been successfully introduced into Aedes aegypti mosquitoes and has been shown to reduce the transmission of dengue and other Aedes-borne viruses. Here we report the entomological results from phased, large-scale releases of Wolbachia infected Ae. aegypti mosquitoes throughout three contiguous cities located in the Aburrá Valley, Colombia.

Local wMel Wolbachia-infected Ae. aegypti mosquitoes were generated and then released in an initial release pilot area in 2015-2016, which resulted in the establishment of Wolbachia in the local mosquito populations. Subsequent large-scale releases, mainly involving vehicle-based releases of adult mosquitoes along publicly accessible roads and streets, were undertaken across 29 comunas throughout Bello, Medellín and Itagüí Colombia between 2017-2022. In 9 comunas these were supplemented by egg releases that were undertaken by staff or community members. By the most recent monitoring, Wolbachia was found to be stable and established at consistent levels in local mosquito populations (>60% prevalence) in the majority (67%) of areas.

CONCLUSION: These results, from the largest contiguous releases of wMel Wolbachia mosquitoes to date, highlight the operational feasibility of implementing the method in large urban settings. Based on results from previous studies, we expect that Wolbachia establishment will be sustained long term. Ongoing monitoring will confirm Wolbachia persistence in local mosquito populations and track its establishment in the remaining areas.

RevDate: 2023-12-01

Bawm S, Khaing Y, Chel HM, et al (2023)

Molecular detection of Dirofilaria immitis and its Wolbachia endosymbionts in dogs from Myanmar.

Current research in parasitology & vector-borne diseases, 4:100148.

Heartworm disease in dogs and cats caused by Dirofilaria immitis continues to be a major clinical issue globally. This study focused on dogs suspicious of having tick-borne diseases (TBD) brought to a clinic and a veterinary teaching hospital in Myanmar. Blood samples were collected and initially screened using SNAP® 4Dx® Plus test kit. All dog blood samples were subjected to conventional PCR to detect both Dirofilaria spp. (cox1 gene) and Wolbachia spp. (16S rDNA) infections. Infection with D. immitis was detected in 14 (28.0%) of 50 examined samples, while the detection rate of TBD causative agents, including Anaplasma phagocytophilum and Ehrlichia canis, was 26.0% (13/50) and 26.0% (13/50), respectively, as determined by ELISA rapid test. In this study, D. immitis infection was moderately but significantly correlated with TBD infections (Pearson's r = 0.397, P = 0.008). Comparative sequence and phylogenetic analyses provided molecular identification of D. immitis in Myanmar and confirmed the identity of its Wolbachia endosymbiont with Wolbachia endosymbionts isolated from D. immitis, Rhipicephalus sanguineus and Aedes aegypti. The present study contributes to our understanding of the coexistence of D. immitis and Wolbachia endosymbiosis in dogs, and the findings may benefit the future prevention and control of dirofilariasis in dogs.

RevDate: 2023-12-01

McPherson AE, Abram PK, Curtis CI, et al (2023)

Dynamic changes in Wolbachia infection over a single generation of Drosophila suzukii, across a wide range of resource availability.

Ecology and evolution, 13(11):e10722.

Wolbachia bacteria are maternally inherited symbionts that commonly infect terrestrial arthropods. Many Wolbachia reach high frequencies in their hosts by manipulating their reproduction, for example by causing reproductive incompatibilities between infected male and uninfected female hosts. However, not all strains manipulate reproduction, and a key unresolved question is how these non-manipulative Wolbachia persist in their hosts, often at intermediate to high frequencies. One such strain, wSuz, infects the invasive fruit pest Drosophila suzukii, spotted-wing drosophila. Here, we tested the hypothesis that wSuz infection provides a competitive benefit when resources are limited. Over the course of one season, we established population cages with varying amounts of food in a semi-field setting and seeded them with a 50:50 mixture of flies with and without Wolbachia. We predicted that Wolbachia-infected individuals should have higher survival and faster development than their uninfected counterparts when there was little available food. We found that while food availability strongly impacted fly fitness, there was no difference in development times or survival between Wolbachia-infected and uninfected flies. Interestingly, however, Wolbachia infection frequencies changed dramatically, with infections either increasing or decreasing by as much as 30% in a single generation, suggesting the possibility of unidentified factors shaping Wolbachia infection over the course of the season.

RevDate: 2023-11-30
CmpDate: 2023-11-30

Dai X, Quan Q, J Jiao (2023)

Modelling and analysis of periodic impulsive releases of the Nilaparvata lugens infected with wStri-Wolbachia.

Journal of biological dynamics, 17(1):2287077.

In this paper, we formulate a population suppression model and a population replacement model with periodic impulsive releases of Nilaparvata lugens infected with wStri. The conditions for the stability of wild-N.lugens-eradication periodic solution of two systems are obtained by applying the Floquet theorem and comparison theorem. And the sufficient conditions for the persistence in the mean of wild N.lugens are also given. In addition, the sufficient conditions for the extinction and persistence of the wild N.lugens in the subsystem without wLug are also obtained. Finally, we give numerical analysis which shows that increasing the release amount or decreasing the release period are beneficial for controlling the wild N.lugens, and the efficiency of population replacement strategy in controlling wild populations is higher than that of population suppression strategy under the same release conditions.

RevDate: 2023-11-28

Azarm A, Koosha M, Dalimi A, et al (2023)

Association Between Wolbachia Infection and Susceptibility to Deltamethrin Insecticide in Phlebotomus papatasi (Diptera: Psychodidae), the Main Vector of Zoonotic Cutaneous Leishmaniasis.

Vector borne and zoonotic diseases (Larchmont, N.Y.) [Epub ahead of print].

Background: Phlebotomus papatasi (Diptera: Psychodidae) is the main vector of zoonotic cutaneous leishmaniasis. Wolbachia is a symbiotic alphaproteobacteria of arthropods that can be involved in susceptibility or resistance. This study aimed to investigate the relationship between Wolbachia and Deltamethrin susceptibility/resistance in Ph. papatasi. Deltamethrin filter papers (0.00002%) were used to test sand fly field collected from southern Iran. After the test, PCR amplification of the Wolbachia surface protein gene (wsp) was used to measure Wolbachia infection rate in the killed, surviving, and control groups. Result: The rates of infection by Wolbachia strain (wPap, super group A) differed between killed (susceptible) and surviving (resistant) Ph. papatasi specimens. The rate of Wolbachia infection in susceptible individuals was more than twice (2.3) (39% vs. 17%) in resistant individuals with the same genetic background. This difference was highly significant (p < 0.001), indicating a positive association between Wolbachia infection and susceptibility to Deltamethrin. In addition, the results showed that Deltamethrin can act as a PCR inhibitor during detection of Wolbachia in Ph. papatasi. Conclusion: Results of this study show that Wolbachia is associated with Deltamethrin susceptibility level in Ph. papatasi. Also, as Deltamethrin has been identified as a PCR inhibitor, great care must be taken in interpreting Wolbachia infection status in infected populations. The results of this study may provide information for a better understanding of the host-symbiont relationship, as well as application of host symbiosis in pest management.

RevDate: 2024-01-08
CmpDate: 2023-11-29

Zhang H, Trueman E, Hou X, et al (2023)

Different mechanisms of X-ray irradiation-induced male and female sterility in Aedes aegypti.

BMC biology, 21(1):274.

BACKGROUND: Aedes aegypti (Ae. aegypti) is the major vector that transmits many diseases including dengue, Zika, and filariasis in tropical and subtropical regions. Due to the growing resistance to chemical-based insecticides, biological control methods have become an emerging direction to control mosquito populations. The sterile insect technique (SIT) deploys high doses of ionizing radiation to sterilize male mosquitoes before the release. The Wolbachia-based population suppression method of the incompatible insect technique (IIT) involves the release of Wolbachia-infected males to sterilize uninfected field females. Due to the lack of perfect sex separation tools, a low percentage of female contamination is detected in the male population. To prevent the unintentional release of these Wolbachia-infected females which might result in population replacement, a low dose of X-ray irradiation is deployed to sterilize any female escapees. However, it remains unclear whether these irradiation-induced male and female sterilizations share common mechanisms.

RESULTS: In this work, we set out to define the minimum dose of X-ray radiation required for complete female sterilization in Ae. aegypti (NEA-EHI strain). Further results showed that this minimum dose of X-ray irradiation for female sterilization significantly reduced male fertility. Similar results have been reported previously in several operational trials. By addressing the underlying causes of the sterility, our results showed that male sterility is likely due to chromosomal damage in the germ cells induced by irradiation. In contrast, female sterility appears to differ and is likely initiated by the elimination of the somatic supporting cells, which results in the blockage of the ovariole maturation. Building upon these findings, we identified the minimum dose of X-ray irradiation on the Wolbachia-infected NEA-EHI (wAlbB-SG) strain, which is currently being used in the IIT-SIT field trial. Compared to the uninfected parental strain, a lower irradiation dose could fully sterilize wAlbB-SG females. This suggests that Wolbachia-carrying mosquitoes are more sensitive to irradiation, consistent with a previous report showing that a lower irradiation dose fully sterilized Wolbachia-infected Ae. aegypti females (Brazil and Mexican strains) compared to those uninfected controls.

CONCLUSIONS: Our findings thus reveal the distinct mechanisms of ionizing X-ray irradiation-induced male or female sterility in Ae. aegypti mosquitoes, which may help the design of X-ray irradiation-based vector control methods.

RevDate: 2023-11-29
CmpDate: 2023-11-29

Oliveira TMP, Rojas MVR, Amorim JA, et al (2023)

Bacterial diversity on larval and female Mansonia spp. from different localities of Porto Velho, Rondonia, Brazil.

PloS one, 18(11):e0293946.

Studies based on the bacterial diversity present in Mansonia spp. are limited; therefore, the aim of this study was to investigate the bacterial diversity in females and larvae of Mansonia spp., describe the differences between the groups identified, and compare the microbiota of larvae from different collection sites. Sequences of the 16S rRNA region from the larvae and females of Mansonia spp. were analyzed. Diversity analyzes were performed to verify the possible bacterial differences between the groups and the collection sites. The results showed Pseudomonas was the most abundant genus in both females and larvae, followed by Wolbachia in females and Rikenellaceae and Desulfovibrio in larvae. Desulfovibrio and Sulfurospirillum, sulfate- and sulfur-reducing bacteria, respectively, were abundant on the larvae. Aminomonas, an amino acid-degrading bacterium, was found only in larvae, whereas Rickettsia was identified in females. Bacterial diversity was observed between females and larvae of Mansonia and between larvae from different collection sites. In addition, the results suggest that the environment influenced bacterial diversity.

RevDate: 2023-11-27
CmpDate: 2023-11-27

Serbus LR (2024)

A Light in the Dark: Uncovering Wolbachia-Host Interactions Using Fluorescence Imaging.

Methods in molecular biology (Clifton, N.J.), 2739:349-373.

The success of microbial endosymbionts, which reside naturally within a eukaryotic "host" organism, requires effective microbial interaction with, and manipulation of, the host cells. Fluorescence microscopy has played a key role in elucidating the molecular mechanisms of endosymbiosis. For 30 years, fluorescence analyses have been a cornerstone in studies of endosymbiotic Wolbachia bacteria, focused on host colonization, maternal transmission, reproductive parasitism, horizontal gene transfer, viral suppression, and metabolic interactions in arthropods and nematodes. Fluorescence-based studies stand to continue informing Wolbachia-host interactions in increasingly detailed and innovative ways.

RevDate: 2023-11-27
CmpDate: 2023-11-27

Bordenstein SR (2024)

Isolation of Phage WO Particles from Wolbachia-Infected Arthropods.

Methods in molecular biology (Clifton, N.J.), 2739:337-348.

Nearly all arthropod-associated Wolbachia contain intact and/or genomic remnants of phage WO, temperate bacteriophages that facilitate horizontal gene transfer, genomic rearrangement of the bacterial chromosome, and symbiotic interactions between Wolbachia and their arthropod hosts. Integrated prophage WO genomes produce active, lytic particles; but the lack of a cell-free culturing system for Wolbachia render them difficult to purify and study. This chapter describes polyethylene glycol (PEG) precipitation of phage particles from Wolbachia-infected arthropods, followed by confirmation of phage WO isolation and purification using electron microscopy and PCR.

RevDate: 2023-11-27
CmpDate: 2023-11-27

Murphy RO, JF Beckmann (2024)

Using Baker's Yeast to Determine Functions of Novel Wolbachia (and Other Prokaryotic) Effectors.

Methods in molecular biology (Clifton, N.J.), 2739:321-336.

Yeasts are single-celled eukaryotic organisms classified as fungi, mostly in the phylum Ascomycota. Of about 1500 named species, Saccharomyces cerevisiae, also known as baker's yeast, domesticated by humans in the context of cooking and brewing, is a profound genetic tool for exploring functions of novel effector proteins from Wolbachia and prokaryotes in general. Wolbachia is a Gram-negative alpha-proteobacterium that infects up to ~75% of all insects as an obligate intracellular microbe (Jeyaprakash A, Hoy MA, Insect Mol Biol 9:393-405, 2000). Wolbachia's lifestyle presents unique challenges for researchers. Wolbachia cannot be axenically cultured and has never been genetically manipulated. Furthermore, many Wolbachia genes have no known function or well-annotated orthologs in other genomes. Yet given the effects of Wolbachia on host phenotypes, which have considerable practical applications for pest control, they undoubtedly involve secreted effector proteins that interact with host gene products. Studying these effectors is challenging with Wolbachia's current genetic limitations. However, some of the constraints to working with Wolbachia can be overcome by expressing candidate proteins in S. cerevisiae. This approach capitalizes on yeast's small genome (~6500 genes), typical eukaryotic cellular organization, and the sophisticated suite of genetic tools available for its manipulation in culture. Thus, yeast can serve as a powerful mock eukaryotic host background to study Wolbachia effector function. Specifically, yeast is used for recombinant protein expression, drug discovery, protein localization studies, protein interaction mapping (yeast two-hybrid system), modeling chromosomal evolution, and examining interactions between proteins responsible for complex phenotypes in less tractable prokaryotic systems. As an example, the paired genes responsible for Wolbachia-mediated cytoplasmic incompatibility (CI) encode novel proteins with limited homology to other known proteins, and no obvious function. This article details how S. cerevisiae was used as an initial staging ground to explore the molecular basis of one of Wolbachia's trademark phenotypes (CI).

RevDate: 2023-11-27
CmpDate: 2023-11-27

Cortez CT, Murphy RO, Owens IM, et al (2024)

Use of Drosophila Transgenics to Identify Functions for Symbiont Effectors.

Methods in molecular biology (Clifton, N.J.), 2739:301-320.

Wolbachia, one of the most successful and studied insect symbionts, and Drosophila, one of the most understood model insects, can be exploited as complementary tools to unravel mechanisms of insect symbiosis. Although Wolbachia itself cannot be grown axenically as clonal isolates or genetically manipulated by standard methods, its reproductive phenotypes, including cytoplasmic incompatibility (CI), have been elucidated using well-developed molecular tools and precise transgenic manipulations available for Drosophila melanogaster. Current research only scratches the surface of how Drosophila can provide a tool for understanding Wolbachia's evolutionary success and the molecular roles of its genetic elements. Here, we briefly outline basic methodologies inherent to transgenic Drosophila systems that have already contributed significant advances in understanding CI, but may be unfamiliar to those who lack experience in Drosophila genetics. In the future, these approaches will continue providing significant insights into Wolbachia that undoubtedly will be extended to other insect symbionts and their biological capabilities.

RevDate: 2023-11-27
CmpDate: 2023-11-27

Valerio F, Twort VG, A Duplouy (2024)

A Worked Example of Screening Genomic Material for the Presence of Wolbachia Infection.

Methods in molecular biology (Clifton, N.J.), 2739:275-299.

This chapter gives a brief overview of how to screen existing host genomic data for the presence of endosymbionts, such as Wolbachia. The various programs used provide test examples, and the corresponding manuals and discussion boards provide invaluable information. Please do consult these resources.

RevDate: 2023-11-27
CmpDate: 2023-11-27

Valerio F, Twort VG, A Duplouy (2024)

Screening Host Genomic Data for Wolbachia Infections.

Methods in molecular biology (Clifton, N.J.), 2739:251-274.

Less than a decade ago, the production of Wolbachia genomic assemblies was tedious, time-consuming, and expensive. The production of Wolbachia genomic DNA free of contamination from host DNA, as required for Wolbachia-targeted sequencing, was then only possible after the amplification and extraction of a large amount of clonal Wolbachia DNA. However, as an endosymbiotic bacterium, Wolbachia does not grow outside the host cell environment, and large-scale recovery of the bacteria required mass rearing of their host, preferably clones of a single individual to avoid strain genetic diversity, or amplification of cell cultures infected with a single Wolbachia strain. Bacterial DNA could be separated from host DNA based on genomic size. Nowadays, the production of full Wolbachia genomes does not require the physical isolation of the bacterial strains from their respective hosts, and the bacterium is often sequenced as a by-catch of host genomic projects. Here, we provide a step-by-step protocol to (1) identify whether host genome projects contain reads from associated Wolbachia and (2) isolate/retrieve the Wolbachia reads from the rest of the sequenced material. We hope this simple protocol will support many projects aiming at studying diverse Wolbachia genome assemblies.

RevDate: 2023-11-27
CmpDate: 2023-11-27

Chrostek E (2024)

Procedures for the Detection of Wolbachia-Conferred Antiviral Protection in Drosophila melanogaster.

Methods in molecular biology (Clifton, N.J.), 2739:219-237.

Spread of Wolbachia infections in host populations may be enhanced by Wolbachia-conferred protection from viral pathogens. Wolbachia-infected Drosophila melanogaster survive the pathogenic effects of positive-sense single-stranded RNA virus infections at a higher rate than the flies without Wolbachia. The protection can occur with or without detectable reduction in virus titer. For the comparisons to be meaningful, Wolbachia-harboring and Wolbachia-free insects need to be genetically matched, and original populations of gut microbiota need to be restored after the removal of Wolbachia using antibiotics. Here, I describe the procedures needed to detect Wolbachia-conferred antiviral protection against Drosophila C virus measured as the difference in survival and viral titer between flies with and without Wolbachia.

RevDate: 2023-11-27
CmpDate: 2023-11-27

Walker T (2024)

Detection of Natural Wolbachia Strains in Anopheles Mosquitoes.

Methods in molecular biology (Clifton, N.J.), 2739:205-218.

Wolbachia is an endosymbiotic bacterium that naturally infects many insect species, including mosquitoes that transmit human diseases. Wolbachia strains have been shown to inhibit the transmission of both arboviruses and malaria Plasmodium parasites. The existence of natural strains in wild Anopheles (An.) mosquitoes, the vectors of malaria parasites, in an endosymbiotic relationship is still to be fully determined. Although Wolbachia has been reported to be present in wild populations of the An. gambiae complex, the primary vectors of malaria in Sub-Saharan Africa, Wolbachia DNA sequence density and infection frequencies are low. As most studies have used highly sensitive nested PCR as the only detection method, more robust evidence is required to determine whether Wolbachia strains are established as endosymbionts in Anopheles species. Techniques such as fluorescent in situ hybridization, microbiome sequencing, and Wolbachia whole genome sequencing have provided concrete evidence for genuine Wolbachia strains in two mosquito species: An. moucheti and An. demeilloni. In this chapter, the current methodology used to determine if resident strains exist in Anopheles mosquitoes will be reviewed, including both PCR- and non-PCR-based protocols.

RevDate: 2023-11-27
CmpDate: 2023-11-27

Ross PA (2024)

Measuring Host Fitness Effects and Transmission of Wolbachia Strains in Aedes aegypti Mosquitoes.

Methods in molecular biology (Clifton, N.J.), 2739:189-203.

Lines of Aedes aegypti mosquitoes infected with heritable Wolbachia bacteria are being developed and released for arbovirus control. Coordinated releases of lab-reared Wolbachia mosquitoes have reduced local disease incidence by spreading virus-blocking Wolbachia strains and by crashing mosquito populations through incompatible male releases. The phenotypic effects of Wolbachia are diverse and depend on both genetics and the environment. Accurate assessments of Wolbachia effects in mosquitoes are essential, as such effects can make the difference between success and failure of a Wolbachia release program. This chapter provides guidelines for testing key Wolbachia host effects and transmission in Aedes aegypti: the most important arbovirus vector and the most common target of Wolbachia release programs. The protocols should be useful for evaluating mosquito strains prior to field release.

RevDate: 2023-11-27
CmpDate: 2023-11-27

Zhang M, Z Xi (2024)

Wolbachia Transinfection Via Embryonic Microinjection.

Methods in molecular biology (Clifton, N.J.), 2739:175-188.

The process of transferring Wolbachia from one species to another to establish a stable, maternally inherited infection in the target species is known as transinfection. The success of transinfection is primarily achieved through embryonic microinjection, which is the most direct and efficient means of delivering Wolbachia into the germline of the target species and establishing stable maternal transmission. For the fundamental studies, transinfection is often used to characterize Wolbachia-host interactions, including Wolbachia host range, the role of host or bacterial factors in symbiosis, and evolution of Wolbachia-host associations. For the applied studies, use of transinfection to generate a novel infection in the target species is the first step to build the weapon for both population replacement and population suppression for controlling insect pests or their transmitted diseases. For the primary dengue vector Aedes aegypti and Anopheles vectors of malaria, which either do not naturally carry Wolbachia or are infected with strains that lack necessary features for implementation, transinfection can be established by introducing a novel strain capable of inducing both cytoplasmic incompatibility (CI) and pathogen blocking. For A. albopictus and Culex mosquito species, which naturally harbor CI-inducing Wolbachia, transinfection can be achieved by either introducing a novel strain to generate superinfection or replacing the native infection with a different Wolbachia strain in a symbiont-free line, which is derived from antibiotic treatment of the wild type. Here, we use A. aegypti as an example to describe the Wolbachia transinfection method, which can be adapted to other insect species, such as planthoppers, according to their specific developmental requirements.

LOAD NEXT 100 CITATIONS

ESP Quick Facts

ESP Origins

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

ESP Support

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

ESP Rationale

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

ESP Goal

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

ESP Usage

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

ESP Content

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

ESP Help

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

ESP Plans

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

Electronic Scholarly Publishing
961 Red Tail Lane
Bellingham, WA 98226

E-mail: RJR8222 @ gmail.com

Papers in Classical Genetics

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

Digital Books

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

Timelines

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

Biographies

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

Selected Bibliographies

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

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