Wolbachia Bacteria Research Articles

Using Wolbachia Bacteria to Control Mosquito-Borne Disease

This publication is intended for both the general public and mosquito control professionals. It outlines the use of the bacterium Wolbachia pipientis as a tool to control mosquito populations and reduce the spread of mosquito-borne disease. Biting mosquitoes transmit many pathogens that cause deadly diseases in people, our pets, and our livestock. Collectively, malaria, dengue, West Nile, filariasis, and other mosquito-borne diseases result in millions of infections and hundreds of thousands of deaths every year. Effective vaccines for most of these have not been developed or are not yet available to the general public, and disease management is focused on controlling mosquito populations. Insecticides have become less effective over the past fifty years as mosquito populations all over the world have developed resistance. This has driven scientists to explore new options for controlling mosquitoes, including using the bacterium Wolbachia pipientis.

Wolbachia infection in natural mosquito populations from Argentina.

The increasing spread of mosquito vectors has made mosquito-borne arboviral diseases a global threat to public health, leading to the urgent need for effective population control methods. Strategies based in the intracellular bacterium Wolbachia Hertig, 1936 are considered environmentally friendly, safe for humans, and potentially cost-effective for controlling arboviral diseases. To minimize undesirable side effects, it is relevant to assess whether Wolbachia is present in the area and understand the diversity associated with native infections before implementing these strategies. With this purpose, we investigated Wolbachia infection status, diversity, and prevalence in populations of Aedes albifasciatus (Macquart, 1838), Aedes fluviatilis (Lutz, 1904), and hybrids of the Culex pipiens (Linnaeus, 1758) complex from Argentina. Aedes albifasciatus and C. pipiens complex samples were collected in the province of Buenos Aires, and A. fluviatilis in the province of Misiones. Aedes albifasciatus was found to be uninfected, while infections with strains wFlu and wPip were detected in A. fluviatilis and hybrids of the C. pipiens complex, respectively. All strains were fixed or close to fixation and clustered within supergroup B. These finding provides valuable information on Wolbachia strains found in natural mosquito populations in Argentina that might be used in heterologous infections in the future or be considered when designing control strategies based on Wolbachia infection.

Stable introduction of Wolbachia wPip into invasive Anopheles stephensi for potential malaria control.

The spread and invasion of the urban malaria vector Anopheles stephensi has emerged as a significant threat to ongoing malaria control and elimination efforts, particularly in Africa. The successful use of the maternally inherited endosymbiotic bacterium Wolbachia for arbovirus control has inspired the exploration of similar strategies for managing malaria vectors, necessitating the establishment of a stable Wolbachia-Anopheles symbiosis. In this study, we successfully transferred Wolbachia wPip into An. stephensi, resulting in the establishment of a stable transinfected HP1 line with 100% maternal transmission efficiency. We demonstrate that wPip in the HP1 line induces nearly complete unidirectional cytoplasmic incompatibility (CI) and maintains high densities in both somatic and germline tissues. Despite a modest reduction in lifespan and female reproductive capacity, our results suggest the Wolbachia infection in the HP1 line has little impact on life history traits, body size, and male mating competitiveness, as well as the ability of its larvae to tolerate rearing temperatures up to 38°C, although wPip densities moderately decrease when larvae are exposed to a constant 33°C and diurnal cyclic temperatures of 27-36°C and 27-38°C. These findings highlight the potential of the HP1 line as a robust candidate for further development in malaria control.

Vector competence of Aedes albopictus field populations from Reunion Island exposed to local epidemic dengue viruses

Dengue virus (DENV) is the most prevalent mosquito-borne Flavivirus that affects humans worldwide. Aedes albopictus, which is naturally infected with the bacteria Wolbachia, is considered to be a secondary vector of DENV. However, it was responsible for a recent DENV outbreak of unprecedented magnitude in Reunion Island, a French island in the South West Indian Ocean. Moreover, the distribution of the cases during this epidemic showed a spatially heterogeneous pattern across the island, leading to questions about the differential vector competence of mosquito populations from different geographic areas. The aim of this study was to gain a better understanding of the vector competence of the Ae. albopictus populations from Reunion Island for local DENV epidemic strains, while considering their infection by Wolbachia. Experimental infections were conducted using ten populations of Ae. albopictus sampled across Reunion Island and exposed to three DENV strains: one strain of DENV serotype 1 (DENV-1) and two strains of DENV serotype 2 (DENV-2). We analyzed three vector competence parameters including infection rate, dissemination efficiency and transmission efficiency, at different days post-exposition (dpe). We also assessed whether there was a correlation between the density of Wolbachia and viral load/vector competence parameters. Our results show that the Ae. albopictus populations tested were not able to transmit the two DENV-2 strains, while transmission efficiencies up to 40.79% were observed for the DENV-1 strain, probably due to difference in viral titres. Statistical analyses showed that the parameters mosquito population, generation, dpe and area of sampling significantly affect the transmission efficiencies of DENV-1. Although the density of Wolbachia varied according to mosquito population, no significant correlation was found between Wolbachia density and either viral load or vector competence parameters for DENV-1. Our results highlight the importance of using natural mosquito populations for a better understanding of transmission patterns of dengue.

Effects of developmental stages, sex difference, and diet types of the host marmalade hoverfly (Episyrphus balteatus) on symbiotic bacteria.

Symbiotic bacteria play key roles in a variety of important life processes of insects such as development, reproduction and environmental adaptation, and the elucidation of symbiont population structure and dynamics is crucial for revealing the underlying regulatory mechanisms. The marmalade hoverfly (Episyrphus balteatus) is not only a remarkable aphid predator, but also a worldwide pollinator second to honeybees. However, its symbiont composition and dynamics remain unclear. Herein, we investigate the symbiotic bacterial dynamics in marmalade hoverfly throughout whole life cycle, across two sexes, and in its prey Megoura crassicauda by 16S rRNA sequencing. In general, the dominant phyla were Proteobacteria and Firmicutes, and the dominant genera were Serratia and Wolbachia. Serratia mainly existed in the larval stage of hoverfly with the highest relative abundance of 86.24% in the 1st instar larvae. Wolbachia was found in adults and eggs with the highest relative abundance of 62.80% in eggs. Significant difference in species diversity was observed between the adults feeding on pollen and larvae feeding on M. crassicauda, in which the dominant symbiotic bacteria were Asaia and Serratia, respectively. However, between two sexes, the symbionts exhibited high similarity in species composition. In addition, our results suggested that E. balteatus obtainded Serratia mainly through horizontal transmission by feeding on prey aphids, whereas it acquired Wolbachia mainly through intergeneration vertical transmission. Taken together, our study revealed the effects of development stages, diet types and genders of E. balteatus on symbionts, and explored transmission modes of dominant bacteria Serratia and Wolbachia. Our findings lay a foundation for further studying the roles of symbiotic bacteria in E. balteatus life cycle, which will benefit for revealing the co-adaptation mechanisms of insects and symbiotic bacteria.

Wolbachia strain diversity in a complex group of sympatric cryptic parasitoid wasp species

BackgroundMaternally-inherited symbionts can induce pre-mating and/or post-mating reproductive isolation between sympatric host lineages, and speciation, by modifying host reproductive phenotypes. The large parasitoid wasp genus Cotesia (Braconidae) includes a diversity of cryptic species, each specialized in parasitizing one to few related Lepidoptera host species. Here, we characterized the infection status of an assemblage of 21 Cotesia species from 15 countries by several microbial symbionts, as a first step toward investigating whether symbionts may provide a barrier to gene flow between these parasitoid host lineages.ResultsThe symbiotic microbes Arsenophonus, Cardinium, Microsporidium and Spiroplasma were not detected in the Cotesia wasps. However, the endosymbiotic bacterium Wolbachia was present in at least eight Cotesia species, and hence we concentrated on it upon screening additional DNA extracts and SRAs from NCBI. Some of the closely related Cotesia species carry similar Wolbachia strains, but most Wolbachia strains showed patterns of horizontal transfer between phylogenetically distant host lineages.ConclusionsThe lack of co-phylogenetic signal between Wolbachia and Cotesia suggests that the symbiont and hosts have not coevolved to an extent that would drive species divergence between the Cotesia host lineages. However, as the most common facultative symbiont of Cotesia species, Wolbachia may still function as a key-player in the biology of the parasitoid wasps. Its precise role in the evolution of this complex clade of cryptic species remains to be experimentally investigated.

Optimization approaches to Wolbachia-based biocontrol

This paper proposes two realistic and biologically viable methods for Wolbachia-based biocontrol of Aedes aegypti mosquitoes, assuming imperfect maternal transmission of the Wolbachia bacterium, incomplete cytoplasmic incompatibility, and direct loss of Wolbachia infection caused by thermal stress. Both methods are based on optimization approaches and allow for the stable persistence of Wolbachia-infected mosquitoes in the wild Ae. aegypti populations in a minimum time and using the smallest quantity of Wolbachia-carrying insects to release. The first method stems from the continuous-time optimal release strategy, which is further transformed into a sequence of suboptimal impulses mimicking instantaneous releases of Wolbachia-carrying insects. The second method constitutes a novel alternative to all existing techniques aimed at the design of release strategies. It is developed using metaheuristics (ϵ-constraint method combined with the genetic algorithm) and directly produces a discrete sequence of decisions, where each element represents the quantity of Wolbachia-carrying mosquitoes to be released instantaneously and only once per a specified time unit. It turns out that a direct discrete-time optimization (second method) renders better quantifiable results compared to transforming a continuous-time optimal release function into a sequence of suboptimal impulses (first method). As an illustration, we provide examples of daily, weekly, and fortnightly release strategies designed by both methods for two Wolbachia strains, wMel and wMelPop.

Wolbachia and mosquitoes: Exploring transmission modes and coevolutionary dynamics in Shandong Province, China.

Vector-borne diseases leave a large footprint on global health. Notable culprits include West Nile virus (WNV), St. Louis encephalitis virus (SLEV), and Japanese encephalitis virus (JEV), all transmitted by Culex mosquitoes. Chemical insecticides have been widely used to reduce the spread of mosquito-borne diseases. Still, mosquitoes are becoming more and more resistant to most chemical insecticides which cause particular harm to the ecology. Wolbachia belongs to the family Ehrlichiaceae in the order Rickettsiales and is a matrilineally inherited endosymbiont present in 60% of insects in nature. Wolbachia is capable of inducing a wide range of reproductive abnormalities in its hosts, such as cytoplasmic incompatibility, and can alter mosquito resistance to pathogen infection. Wolbachia has been proposed as a biological alternative to chemical vector control, and specific research progress and effectiveness have been achieved. Despite the importance of Wolbachia, this strategy has not been tested in Culex pipiens pallens, the most prevalent mosquito species in Shandong Province, China. Little is known about how the mass release of Wolbachia-infected mosquitoes may impact the genetic structure of Culex pipiens pallens, and how the symbiotic bacterium Wolbachia interacts with mitochondria during host mosquito transmission. Based on the population genetic structure of Culex pipiens pallens in Shandong Province, this study investigated the infection rate and infection type of Wolbachia in Shandong Province and jointly analysed the evolutionary relationship between the host mosquito and the symbiotic bacterium Wolbachia. Our study showed that Wolbachia naturally infected by Culex pipiens pallens in Shandong Province was less homologous to Wolbachia infected by Aedes albopictus released from mosquito factory in Guangzhou. Our results also show that Culex pipiens pallens is undergoing demographic expansion in Shandong Province. The overall Wolbachia infection rate of Culex pipiens pallens was 92.8%, and a total of 15 WSP haplotypes were detected. We found that the genetic diversity of Wolbachia was low in Culex pipiens pallens from Shandong Province, and the mosquitoes were infected only with type B Wolbachia. Visualizing the relationship between Culex pipiens pallens and Wolbachia using a tanglegram revealed patterns of widespread associations. A specific coevolutionary relationship exists between the host mosquito and Wolbachia. Knowledge of this mosquito-Wolbachia relationship will provide essential scientific information required for Wolbachia-based vector control approaches in Shandong Province and will lead to a better understanding of the diversity and evolution of Wolbachia for its utility as a biocontrol agent.

Addictive manipulation: a perspective on the role of reproductive parasitism in the evolution of bacteria-eukaryote symbioses.

Wolbachia bacteria encompass noteworthy reproductive manipulators of their arthropod hosts. which influence host reproduction to favour their own transmission, also exploiting toxin-antitoxin systems. Recently, multiple other bacterial symbionts of arthropods have been shown to display comparable manipulative capabilities. Here, we wonder whether such phenomena are truly restricted to arthropod hosts. We focused on protists, primary models for evolutionary investigations on eukaryotes due to their diversity and antiquity, but still overall under-investigated. After a thorough re-examination of the literature on bacterial-protist interactions with this question in mind, we conclude that such bacterial 'addictive manipulators' of protists do exist, are probably widespread, and have been overlooked until now as a consequence of the fact that investigations are commonly host-centred, thus ineffective to detect such behaviour. Additionally, we posit that toxin-antitoxin systems are crucial in these phenomena of addictive manipulation of protists, as a result of recurrent evolutionary repurposing. This indicates intriguing functional analogy and molecular homology with plasmid-bacterial interplays. Finally, we remark that multiple addictive manipulators are affiliated with specific bacterial lineages with ancient associations with diverse eukaryotes. This suggests a possible role of addictive manipulation of protists in paving the way to the evolution of bacteria associated with multicellular organisms.

Wolbachia Promotes an Anti-Angiogenic Response Using an In Vitro Model of Vascular Endothelial Cells in Relation to Heartworm Disease.

Heartworm disease caused by Dirofilaria immitis is a vector-borne zoonotic disease responsible for the infection of mainly domestic dogs and cats, or these are those for which the most data are known. Humans are an accidental host where a benign, asymptomatic pulmonary nodule may originate. Dirofilaria immitis also harbours the endosymbiont bacteria of the genus Wolbachia, which play a role in moulting, embryogenesis, inflammatory pathology, and immune response. When Wolbachia sp. is released into the bloodstream, endothelial and pulmonary damage is exacerbated, further encouraging thrombus formation and pulmonary hypertension, facilitating congestive heart failure and death of the animal. Previous studies have shown that parasite excretory/secretory products are able to activate the pro-angiogenic pathway (formation of new vessels) to facilitate parasite survival. The aim of this study was to analyse the role of Wolbachia sp. and its relationship with the cellular processes and the angiogenic pathway in a model of human endothelial cells in vitro. The use of recombinant Wolbachia Surface Protein (rWSP) showed that its stimulation exerted an anti-angiogenic effect by detecting an increase in the production of VEGFR-1/sFlt1 and sEndoglin and did not affect the production of VEGFR-2 and mEndoglin (pro-angiogenic molecules). Furthermore, it did not stimulate cell proliferation or migration, although it did negatively stimulate the formation of pseudocapillaries, slowing down this process. These cellular processes are directly related to the angiogenic pathway so, with these results, we can conclude that Wolbachia sp. is related to the stimulation of the anti-angiogenic pathway, not facilitating the survival of D. immitis in vascular endothelium.

Low-input PacBio sequencing generates high-quality individual fly genomes and characterizes mutational processes

Long-read sequencing, exemplified by PacBio, revolutionizes genomics, overcoming challenges like repetitive sequences. However, the high DNA requirement ( > 1 µg) is prohibitive for small organisms. We develop a low-input (100 ng), low-cost, and amplification-free library-generation method for PacBio sequencing (LILAP) using Tn5-based tagmentation and DNA circularization within one tube. We test LILAP with two Drosophila melanogaster individuals, and generate near-complete genomes, surpassing preexisting single-fly genomes. By analyzing variations in these two genomes, we characterize mutational processes: complex transpositions (transposon insertions together with extra duplications and/or deletions) prefer regions characterized by non-B DNA structures, and gene conversion of transposons occurs on both DNA and RNA levels. Concurrently, we generate two complete assemblies for the endosymbiotic bacterium Wolbachia in these flies and similarly detect transposon conversion. Thus, LILAP promises a broad PacBio sequencing adoption for not only mutational studies of flies and their symbionts but also explorations of other small organisms or precious samples.

Modelling suggests Wolbachia-induced cytoplasmic incompatibility in oak gall wasps with cyclical parthenogenesis.

Oak gall wasps typically exhibit a life cycle with one sexual and one asexual generation each year. These wasps can carry various endosymbionts, one of which is the maternally inherited bacterium Wolbachia that can induce several reproductive manipulations on its host. Cytoplasmic incompatibility (CI) has been described as the most prominent of these manipulations. CI leads to embryonic mortality in the hosts' offspring when infected males mate with either uninfected females or with females that harbour different Wolbachia strains. It has been hypothesized that Wolbachia can induce CI in oak gall wasps. To address this hypothesis, we derived a mathematical model to investigate the spread of a bacterial infection in naive populations and to determine the plausibility of CI occurrence. To validate our model, we used published data from Wolbachia-infected Belonocnema kinseyi populations in two approaches. Our first approach uses measurements of infection frequencies and maternal transmission in the sexual generation. For the second approach, we extended the model to compare predictions to estimates of mtDNA-haplotypes, which, like Wolbachia, are maternally inherited, and can therefore be associated with the infection. Both approaches indicate that CI is present in these populations. Our model can be generalized to investigate the occurrence of CI not only for oak gall wasps but also for other species.

A specific innate immune response silences the virulence of Pseudomonas aeruginosa in a latent infection model in the Drosophila melanogaster host.

Microbial pathogenicity often depends on the route of infection. For instance, P. aeruginosa or S. marcescens cause acute systemic infections when low numbers of bacteria are injected into D. melanogaster flies whereas flies succumb much slower to the continuous ingestion of these pathogens, even though both manage to escape from the gut compartment and reach the hemocoel. Here, we have developed a latent P. aeruginosa infection model by feeding flies on the bacteria for a short period. The bacteria stably colonize internal tissues yet hardly cause any damage since latently-infected flies live almost as long as noninfected control flies. The apparently dormant bacteria display particular characteristics in terms of bacterial colony morphology, composition of the outer cell wall, and motility. The virulence of these bacteria can however be reactivated upon wounding the host. We show that melanization but not the cellular or the systemic humoral response is the predominant host defense that establishes latency and may coerce the bacteria to a dormant state. In addition, the lasting activation of the melanization responses in latently-infected flies provides a degree of protection to the host against a secondary fungal infection. Latent infection by an ingested pathogen protects against a variety of homologous or heterologous systemic secondary infectious challenges, a situation previously described for the endosymbiotic Wolbachia bacteria, a guard against viral infections.

Вопросы эпидемиологии дирофиляриоза в России и Европе в XXI веке

The participation of mosquitoes in the epidemiological process of invasion caused by Dirofilaria spp. – parasites of carnivorous animals and humans is considered. Mosquitoes of the genera Aedes (Stegomyia), Culex, Anopheles, Coquillettidia (Mansonia) participate in the transmission of microfilariae – larvae of helminths. The problem of dirofilariasis is especially acute in cities in the presence of infected dogs, primarily service and stray dogs, and mosquitoes, which contributes to the year-round transmission of the invasion by vector. According to Rospotrebnadzor, since 2016 There is a tendency to increase the incidence of dirofilariasis among the Russian population. The methods of treatment of dirofilariasis are surgical. No dirofilariasis has been detected in mosquitoes infected with the Wolbachia bacterium. Keywords: morbidity, infection, spread, dirofilariae, mosquitoes, wolbachia, prevention (insecticides, larvicides).

Diversity of Wolbachia infections in Sri Lankan mosquitoes with a new record of Wolbachia Supergroup B infecting Aedes aegypti vector populations

Wolbachia bacteria are common endosymbionts of insects and have recently been applied for controlling arboviral vectors, especially Aedes aegypti mosquito populations. However, several medically important mosquito species in Sri Lanka were present with limited information for the Wolbachia infection status. Therefore, the screening of Wolbachia in indigenous mosquitoes is required prior to a successful application of Wolbachia-based vector control strategy. In this study, screening of 78 mosquito species collected from various parts of the country revealed that 13 species were positive for Wolbachia infection, giving ~ 17% infection frequency of Wolbachia among the Sri Lankan mosquitoes. Twelve Wolbachia-positive mosquito species were selected for downstream Wolbachia strain genotyping using Multi Locus Sequencing Type (MLST), wsp gene, and 16S rRNA gene-based approaches. Results showed that these Wolbachia strains clustered together with the present Wolbachia phylogeny of world mosquito populations with some variations. Almost 90% of the mosquito populations were infected with supergroup B while the remaining were infected with supergroup A. A new record of Wolbachia supergroup B infection in Ae. aegypti, the main vectors of dengue, was highlighted. This finding was further confirmed by real-time qPCR, revealing Wolbachia density variations between Ae. aegypti and Ae. albopictus (p = 0.001), and between males and females (p < 0.05). The evidence of natural Wolbachia infections in Ae. aegypti populations in Sri Lanka is an extremely rare incident that has the potential to be used for arboviral vector control.

Dual RNA-seq in filarial nematodes and Wolbachia endosymbionts using RNase H based ribosomal RNA depletion.

Lymphatic filariasis is caused by parasitic nematodes and is a leading cause of disability worldwide. Many filarial worms contain the bacterium Wolbachia as an obligate endosymbiont. RNA sequencing is a common technique used to study their molecular relationships and to identify potential drug targets against the nematode and bacteria. Ribosomal RNA (rRNA) is the most abundant RNA species, accounting for 80-90% of the RNA in a sample. To reduce sequencing costs, it is necessary to remove ribosomal reads through poly-A enrichment or ribosomal depletion. Bacterial RNA does not contain a poly-A tail, making it difficult to sequence both the nematode and Wolbachia from the same library preparation using standard poly-A selection. Ribosomal depletion can utilize species-specific oligonucleotide probes to remove rRNA through pull-down or degradation methods. While species-specific probes are commercially available for many commonly studied model organisms, there are currently limited depletion options for filarial parasites. Here, we performed total RNA sequencing from Brugia malayi containing the Wolbachia symbiont (wBm) and designed ssDNA depletion probes against their rRNA sequences. We compared the total RNA library to poly-A enriched, Terminator 5'-Phosphate-Dependent Exonuclease treated, NEBNext Human/Bacteria rRNA depleted and our custom nematode probe depleted libraries. The custom nematode depletion library had the lowest percentage of ribosomal reads across all methods, with a 300-fold decrease in rRNA when compared to the total RNA library. The nematode depletion libraries also contained the highest percentage of Wolbachia mRNA reads, resulting in a 16-1,000-fold increase in bacterial reads compared to the other enrichment and depletion methods. Finally, we found that the Brugia malayi depletion probes can remove rRNA from the filarial worm Dirofilaria immitis and the majority of rRNA from the more distantly related free living nematode Caenorhabditis elegans. These custom filarial probes will allow for future dual RNA-seq experiments between nematodes and their bacterial symbionts from a single sequencing library.

DNA barcoding reveals cryptic species in the sea slater Ligia italica (Crustacea, Isopoda) from Tunisia

Barcoding studies have provided significant insights into phylogenetic relationships among species belonging to the genus Ligia (Crustacea, Isopoda). Herein the diversity of the Italian sea slater Ligia italica from Tunisia is studied for the first time. Samples were collected from 18 localities in Tunisia, and the analysis included previously published sequences from Italy and Greece available in GenBank. Bayesian and Maximum Likelihood phylogenetic analyses were carried out using a fragment of the mitochondrial COI gene. Putative cryptic species were explored using the ‘barcode gap’ approach in the software ASAP. A genetic landscape shape analysis was carried out using the program Alleles in Space. The analyses revealed highly divergent and well-supported clades of L. italica dispersed across Tunisia (Clades A1 and A2), Greece (Clade B) and Italy (Clades C1 and C2). High genetic dissimilarity among clades suggested that L. italica constitute a cryptic species complex. Divergence among different L. italica lineages (Clades A, B and C) occurred around 7–4.5 Ma. The detected high genetic distances among clades did not result from atypical mitochondrial DNAs or intracellular infection by Wolbachia bacteria. The complex history of the Mediterranean Sea appears to have played a significant role in shaping the phylogeographic pattern of Ligia italica. Additional morphological and molecular studies are needed to confirm the existence of cryptic species in Ligia italica in Mediterranean.

Development, feeding, and sex shape the relative quantity of the nutritional obligatory symbiont Wolbachia in bed bugs.

The common bed bug, Cimex lectularius, is a hemipteran insect that feeds only on blood, and whose bites cause public health issues. Due to globalization and resistance to insecticides, this pest has undergone a significant and global resurgence in recent decades. Blood is an unbalanced diet, lacking notably sufficient B vitamins. Like all strict hematophagous arthropods, bed bugs host a nutritional symbiont supplying B vitamins. In C. lectularius, this nutritional symbiont is the intracellular bacterium Wolbachia (wCle). It is located in specific symbiotic organs, the bacteriomes, as well as in ovaries. Experimental depletion of wCle has been shown to result in longer nymphal development and lower fecundity. These phenotypes were rescued by B vitamin supplementation. Understanding the interaction between wCle and the bed bug may help to develop new pest control methods targeting the disruption of this symbiotic interaction. The objective of this work was thus to quantify accurately the density of wCle over the life cycle of the host and to describe potential associated morphological changes in the bacteriome. We also sought to determine the impact of sex, feeding status, and aging on the bacterial population dynamics. We showed that the relative quantity of wCle continuously increases during bed bug development, while the relative size of the bacteriome remains stable. We also showed that adult females harbor more wCle than males and that wCle relative quantity decreases slightly in adults with age, except in weekly-fed males. These results are discussed in the context of bed bug ecology and will help to define critical points of the symbiotic interaction during the bed bug life cycle.

The MraY Inhibitor Muraymycin D2 and Its Derivatives Induce Enlarged Cells in Obligate Intracellular Chlamydia and Wolbachia and Break the Persistence Phenotype in Chlamydia.

Chlamydial infections and diseases caused by filarial nematodes are global health concerns. However, treatment presents challenges due to treatment failures potentially caused by persisting Chlamydia and long regimens against filarial infections accompanied by low compliance. A new treatment strategy could be the targeting of the reduced peptidoglycan structures involved in cell division in the obligate intracellular bacteria Chlamydia and Wolbachia, the latter being obligate endosymbionts supporting filarial development, growth, and survival. Here, cell culture experiments with C. trachomatis and Wolbachia showed that the nucleoside antibiotics muraymycin and carbacaprazamycin interfere with bacterial cell division and induce enlarged, aberrant cells resembling the penicillin-induced persistence phenotype in Chlamydia. Enzymatic inhibition experiments with purified C. pneumoniae MraY revealed that muraymycin derivatives abolish the synthesis of the peptidoglycan precursor lipid I. Comparative in silico analyses of chlamydial and wolbachial MraY with the corresponding well-characterized enzyme in Aquifex aeolicus revealed a high degree of conservation, providing evidence for a similar mode of inhibition. Muraymycin D2 treatment eradicated persisting non-dividing C. trachomatis cells from an established penicillin-induced persistent infection. This finding indicates that nucleoside antibiotics may have additional properties that can break bacterial persistence.

Wolbachia and Lymphatic Filarial Nematodes and Their Implications in the Pathogenesis of the Disease.

Lymphatic filariasis (LF) is an infection of three closely related filarial worms such as Wuchereria bancrofti, Brugia malayi, and Brugia timori. These worms can cause a devastating disease that involves acute and chronic lymphoedema of the extremities, which can cause elephantiasis in both sexes and hydroceles in males. These important public health nematodes were found to have a mutualistic relationship with intracellular bacteria of the genus Wolbachia, which is essential for the development and survival of the nematode. The host's inflammatory response to parasites and possibly also to the Wolbachia endosymbiont is the cause of lymphatic damage and disease pathogenesis. This review tried to describe and highlight the mutualistic associations between Wolbachia and lymphatic filarial nematodes and the role of bacteria in the pathogenesis of lymphatic filariasis. Articles for this review were searched from PubMed, Google Scholar, and other databases. Article searching was not restricted by publication year; however, only English version full-text articles were included.