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1.
Bull Math Biol ; 84(11): 121, 2022 Sep 16.
Article in English | MEDLINE | ID: mdl-36112293

ABSTRACT

Due to the role of cytoplasmic incompatibility (CI), releasing Wolbachia-infected male mosquitoes into the wild becomes a very promising strategy to suppress the wild mosquito population. When developing a mosquito suppression strategy, our main concerns are how often, and in what amount, should Wolbachia-infected mosquitoes be released under different CI intensity conditions, so that the suppression is most effective and cost efficient. In this paper, we propose a mosquito population suppression model that incorporates suppression and self-recovery under different CI intensity conditions. We adopt the new modeling idea that only sexually active Wolbachia-infected male mosquitoes are considered in the model and assume the releases of Wolbachia-infected male mosquitoes are impulsive and periodic with period T. We particularly study the case where the release period is greater than the sexual lifespan of the Wolbachia-infected male mosquitoes. We define the CI intensity threshold, mosquito release thresholds, and the release period threshold to characterize the model dynamics. The global and local asymptotic stability of the origin and the existence and stability of T-periodic solutions are investigated. Our findings provide useful guidance in designing practical release strategies to control wild mosquitoes.


Subject(s)
Aedes , Wolbachia , Animals , Male , Mathematical Concepts , Models, Biological
2.
Sci Rep ; 12(1): 15245, 2022 Sep 09.
Article in English | MEDLINE | ID: mdl-36085160

ABSTRACT

The mosquito Aedes aegypti is the primary vector of a range of medically important viruses including dengue, Zika, West Nile, yellow fever, and chikungunya viruses. The endosymbiotic bacterium Wolbachia pipientis wAlbB strain is a promising biocontrol agent for blocking viral transmission by Ae. aegypti. To predict the long-term efficacy of field applications, a thorough understanding of the interactions between symbiont, host, and pathogen is required. Wolbachia influences host physiology in a variety of ways including reproduction, immunity, metabolism, and longevity. MicroRNAs (miRNAs) are highly conserved small non-coding RNAs that regulate gene expression in eukaryotes and viruses. Several miRNAs are known to regulate biological processes in Drosophila and mosquitoes, including facilitating Wolbachia maintenance. We generated the first chromosomal map of Ae. aegypti miRNAs, and compared miRNA expression profiles between a wAlbB-transinfected Ae. aegypti mosquito line and a tetracycline cleared derivative, using deep small RNA-sequencing. We found limited modulation of miRNAs in response to wAlbB infection. Several miRNAs were modulated in response to age, some of which showed greater upregulation in wAlbB-infected mosquitoes than in tetracycline cleared ones. By selectively inhibiting some differentially expressed miRNAs, we identified miR-2946-3p and miR-317-3p as effecting mosquito longevity in Wolbachia-infected mosquitoes.


Subject(s)
Aedes , MicroRNAs , Wolbachia , Zika Virus Infection , Zika Virus , Aedes/genetics , Animals , Anti-Bacterial Agents , Drosophila , Longevity/genetics , MicroRNAs/genetics , Mosquito Vectors , Tetracycline
3.
Math Biosci Eng ; 19(11): 11154-11171, 2022 Aug 04.
Article in English | MEDLINE | ID: mdl-36124585

ABSTRACT

Combining Sterile and Incompatible Insect techniques can significantly reduce mosquito populations and prevent the transmission of diseases between insects and humans. This paper describes impulsive differential equations for the control of a mosquito with Wolbachia. Several interesting conditions are created when sterile male mosquitoes are released impulsively, ensuring both open- and closed-loop control. To determine the wild mosquito population size in real-time, we propose an open-loop control system, which uses impulsive and constant releases of sterile male mosquitoes. A closed-loop control scheme is also being investigated, which specifies the release of sterile mosquitoes according to the size of the wild mosquito population. To eliminate or reduce a mosquito population below a certain threshold, the Sterile insect technique involves mass releases of sterile insects. Numerical simulations verify the theoretical results.


Subject(s)
Aedes , Infertility , Wolbachia , Animals , Humans , Male , Mosquito Control/methods , Mosquito Vectors
4.
Rev Sci Tech ; 41(1): 91-99, 2022 May.
Article in English | MEDLINE | ID: mdl-35925631

ABSTRACT

The Wolbachia insect control method, employed by the World Mosquito Program (WMP), relies on introgressing Wolbachia through target Aedes aegypti populations to reduce the incidence of dengue. Since 2010, the WMP has been producing Wolbachia-infected mosquitoes at numerous sites across the globe for release in 11 countries. As the technology has matured, greater focus has been placed on mosquito production at larger central facilities for transport to remote release sites, both domestically and internationally. Of particular note is the production of Wolbachia-infected mosquitoes at the WMP's Australian production facility for successful international deployments in Fiji, Vanuatu, Kiribati and Sri Lanka. This requires careful management of both production and supply-chain processes to ensure that the quality of the mosquito eggs, specifically the hatch rate and Wolbachia infection rate, is maintained. To ensure the cost-effectiveness and scalability of the Wolbachia method, these processes will be further refined to facilitate deployment from large centralised production facilities.


La méthode de contrôle des insectes mise en oeuvre par le World Mosquito Program (WMP) recourt à la bactérie Wolbachia et repose sur l'introgression de cette dernière par le biais des populations cibles d'Aedes aegypti dans le but de réduire l'incidence de la dengue. Depuis 2010, le WMP produit des moustiques infectés par Wolbachia à partir de nombreux sites répartis dans le monde entier en vue de leur lâcher dans 11 pays. Cette technologie s'étant bien développée, l'accent est désormais mis sur la production de moustiques dans des établissements centralisés de plus grande envergure afin de les expédier vers des sites de lâcher éloignés, tant sur le territoire national qu'à l'échelle internationale. Il importe de souligner la production de moustiques infectés par Wolbachia conduite par le WMP sur son site australien et leur déploiement international couronné de succès aux Fidji, au Vanuatu, à Kiribati et au Sri Lanka. Cela nécessite une gestion rigoureuse des procédures aussi bien lors de la production que tout au long de la chaîne d'approvisionnement afin de veiller au maintien de la qualité des oeufs de moustiques et plus spécifiquement du taux d'éclosion et du taux d'infection par Wolbachia. Afin d'assurer la rentabilité et l'évolutivité de la méthode basée sur Wolbachia, ces procédures seront encore affinées afin de faciliter le déploiement à partir de sites de production à grande échelle centralisés.


El método de control de insectos con Wolbachia que emplea el World Mosquito Program (WMP) reposa en la introgresión de Wolbachia a través de poblaciones de Aedes aegypti para reducir la incidencia del dengue. Desde 2010, el WMP viene generando mosquitos infectados por Wolbachia en numerosas instalaciones repartidas por todo el globo, mosquitos que después son liberados en 11 países. A medida que la tecnología ha ido madurando, la tendencia ha sido cada vez más la de concentrar la producción de mosquitos en grandes instalaciones centrales y desde allí enviarlos a los remotos lugares de suelta, ya estén en el mismo país o en otros países. Especialmente destacable es la producción de mosquitos infectados por Wolbachia en las instalaciones que el WMP tiene en Australia, utilizadas con éxito como centro de operaciones para aplicar el método en otros países como Fiji, Vanuatu, Kiribati y Sri Lanka. Ello exige una cuidadosa gestión de los procesos tanto de producción como de la cadena de suministro, que garantice un nivel constante de calidad de los huevos de mosquito, y más concretamente de las tasas de eclosión y de infección por Wolbachia. A fin de asegurar que el método ofrezca una buena relación costo-eficacia y sea reproducible a mayor escala, esos procesos serán perfeccionados para facilitar el despliegue de los insectos a partir de grandes instalaciones de producción centralizada.


Subject(s)
Aedes , Dengue , Wolbachia , Animals , Australia , Dengue/epidemiology , Dengue/veterinary , Mosquito Vectors , Ovum , Pest Control, Biological
5.
PLoS One ; 17(8): e0272028, 2022.
Article in English | MEDLINE | ID: mdl-36037217

ABSTRACT

Philaenus spumarius is a cosmopolitan species that has become a major threat to European agriculture being recognized as the main vector of the introduced plant pathogen Xylella fastidiosa, the agent of the "olive quick decline syndrome", a disease which is devastating olive orchards in southern Italy. Wolbachia are bacterial symbionts of many insects, frequently as reproductive parasites, sometime by establishing mutualistic relationships, able to spread within host populations. Philaenus spumarius harbors Wolbachia, but the role played by this symbiont is unknown and data on the infection prevalence within host populations are limited. Here, the Wolbachia infection rate was analyzed in relation to the geographic distribution and the genetic diversity of the Italian populations of P. spumarius. Analysis of the COI gene sequences revealed a geographically structured distribution of the three main mitochondrial lineages of P. spumarius. Wolbachia was detected in half of the populations sampled in northern Italy where most individuals belonged to the western-Mediterranean lineage. All populations sampled in southern and central Italy, where the individuals of the eastern-Mediterranean lineage were largely prevalent, were uninfected. Individuals of the north-eastern lineage were found only in populations from the Alps in the northernmost part of Italy, at high altitudes. In this area, Wolbachia infection reached the highest prevalence, with no difference between north-eastern and western-Mediterranean lineage. Analysis of molecular diversity of COI sequences suggested no significant effect of Wolbachia on population genetics of P. spumarius. Using the MLST approach, six new Wolbachia sequence types were identified. Using FISH, Wolbachia were observed within the host's reproductive tissues and salivary glands. Results obtained led us to discuss the role of Wolbachia in P. spumarius, the factors influencing the geographic distribution of the infection, and the exploitation of Wolbachia for the control of the vector insect to reduce the spread of X. fastidiosa.


Subject(s)
Hemiptera , Wolbachia , Xylella , Animals , Europe , Genetic Variation , Hemiptera/genetics , Hemiptera/microbiology , Insect Vectors/microbiology , Italy , Multilocus Sequence Typing , Plant Diseases/microbiology , Wolbachia/genetics , Xylella/genetics
6.
PLoS One ; 17(8): e0273668, 2022.
Article in English | MEDLINE | ID: mdl-36040904

ABSTRACT

Wolbachia Hertig, 1936 is an intracellular bacterial symbiont colonizing many arthropods. Of the studies done on the bacteria present in the superfamily Gerroidea Leach, 1815, no report of Wolbachia infection had yet been made. Thus, we checked the presence of Wolbachia in six Gerroidea species which colonize tropical aquatic environments by PCR using wsp primer set before sequencing and phylogenetic analyses. Insects were collected in the marine fringe of mangroves, in river estuaries, in swampy mangroves, and in ponds from Guadeloupe islands (Caribbean). Two new strains of Wolbachia were detected in these Gerroidea. They were named wLfran and wRmang. The wsp sequences suggest that the strains belong to the already described E supergroup or similar. wLfran is present in Limnogonus franciscanus Stål, 1859 and Rheumatobates trinitatis (China, 1943) while wRmang appears to be present exclusively in R. mangrovensis (China, 1943). Three other species were analysed, but did not appear to be infected: Brachymetra albinerva (Amyot & Serville, 1843), Halobates micans Eschscheltz, 1822, and Microvelia pulchella Westwood, 1834. The results presented here highlight for the first time the presence of new intracellular Wolbachia strains in Gerroidea colonising tropical aquatic environments like mangrove habitats from inlands to sea shore.


Subject(s)
Arthropods , Heteroptera , Wolbachia , Animals , Arthropods/microbiology , DNA, Bacterial , Phylogeny , Wolbachia/genetics
7.
Int J Mol Sci ; 23(16)2022 Aug 21.
Article in English | MEDLINE | ID: mdl-36012723

ABSTRACT

The endosymbiotic Wolbachia bacteria frequently cause cytoplasmic incompatibility (CI) in their insect hosts, where Wolbachia-infected males cross with uninfected females, leading to no or fewer progenies, indicating a paternal modification by Wolbachia. Recent studies have identified a Wolbachia protein, CidB, containing a DUB (deubiquitylating enzyme) domain, which can be loaded into host sperm nuclei and involved in CI, though the DUB activity is not necessary for CI in Drosophila melanogaster. To investigate whether and how Wolbachia affect protein ubiquitination in testes of male hosts and are thus involved in male fertility, we compared the protein and ubiquitinated protein expressions in D. melanogaster testes with and without Wolbachia. A total of 643 differentially expressed proteins (DEPs) and 309 differentially expressed ubiquitinated proteins (DEUPs) were identified to have at least a 1.5-fold change with a p-value of <0.05. Many DEPs were enriched in metabolic pathway, ribosome, RNA transport, and post-translational protein modification pathways. Many DEUPs were involved in metabolism, ribosome, and proteasome pathways. Notably, 98.1% DEUPs were downregulated in the presence of Wolbachia. Four genes coding for DEUPs in ubiquitin proteasome pathways were knocked down, respectively, in Wolbachia-free fly testes. Among them, Rpn6 and Rpn7 knockdown caused male sterility, with no mature sperm in seminal vesicles. These results reveal deubiquitylating effects induced by Wolbachia infection, suggesting that Wolbachia can widely deubiquitinate proteins that have crucial functions in male fertility of their hosts, but are not involved in CI. Our data provide new insights into the regulatory mechanisms of endosymbiont/host interactions and male fertility.


Subject(s)
Drosophila melanogaster , Wolbachia , Animals , Cytoplasm/metabolism , Drosophila melanogaster/genetics , Female , Male , Proteasome Endopeptidase Complex/metabolism , Semen , Testis/metabolism
8.
Bull Math Biol ; 84(9): 95, 2022 08 01.
Article in English | MEDLINE | ID: mdl-35913683

ABSTRACT

In this paper, we propose a delay differential equation model to describe the Wolbachia infection dynamics in mosquitoes in which the key factor of cytoplasmic incompactibility (CI) is incorporated in a more natural way than those in the literature. By analyzing the dynamics of the model, we are able to obtain some information on the impact of four important parameters: the competition capabilities of the wild mosquitoes and infected mosquitoes, the maternal transmission level and the CI level. The analytic results show that there are ranges of parameters that support competition exclusion principle, and there are also ranges of parameters that allow co-persistence for both wild and infected mosquitoes. These ranges account for the scenarios of failure of invasion, invasion and suppressing the wild mosquitoes, and invasion and replacing the wild mosquitoes. We also discuss some possible future problems both in mathematics and in modeling.


Subject(s)
Aedes , Wolbachia , Animals , Dichlorodiphenyl Dichloroethylene , Mathematical Concepts , Models, Biological
9.
BMC Microbiol ; 22(1): 209, 2022 08 30.
Article in English | MEDLINE | ID: mdl-36042402

ABSTRACT

BACKGROUND: Maternally inherited bacterial symbionts are extremely widespread in insects. They owe their success to their ability to promote their own transmission through various manipulations of their hosts' life-histories. Many symbionts however very often go undetected. Consequently, we have only a restricted idea of the true symbiont diversity in insects, which may hinder our understanding of even bigger questions in the field such as the evolution or establishment of symbiosis. RESULTS: In this study, we screened publicly available Lepidoptera genomic material for two of the most common insect endosymbionts, namely Wolbachia and Spiroplasma, in 1904 entries, encompassing 106 distinct species. We compared the performance of two screening software, Kraken2 and MetaPhlAn2, to identify the bacterial infections and using a baiting approach we reconstruct endosymbiont genome assemblies. Of the 106 species screened, 20 (19%) and nine (8.5%) were found to be infected with either Wolbachia or Spiroplasma, respectively. Construction of partial symbiotic genomes and phylogenetic analyses suggested the Wolbachia strains from the supergroup B were the most prevalent type of symbionts, while Spiroplasma infections were scarce in the Lepidoptera species screened here. CONCLUSIONS: Our results indicate that many of the host-symbiont associations remain largely unexplored, with the majority of associations we identify never being recorded before. This highlights the usefulness of public databases to explore the hidden diversity of symbiotic entities, allowing the development of hypotheses regarding host-symbiont associations. The ever-expanding genomic databases provide a diverse databank from which one can characterize and explore the true diversity of symbiotic entities.


Subject(s)
Lepidoptera , Spiroplasma , Wolbachia , Animals , Phylogeny , Spiroplasma/genetics , Symbiosis/genetics , Wolbachia/genetics
10.
Acta Trop ; 235: 106624, 2022 Nov.
Article in English | MEDLINE | ID: mdl-35914568

ABSTRACT

Recently, Wolbachia infection has been described in leishmaniasis vector sandflies. This endosymbiont bacterium is present in 60% of insects, and has been suggested as a mechanism of biological control of vector insects, because it causes a series of changes in the invertebrate host. In addition, recent studies have shown that this bacterium can prevent the development of parasites in vector insects. In this context, the present study aims to molecularly characterize the circulating strain of this bacterium in sandflies in the State of Bahia, Brazil, as well as the natural infection rate of Leishmania sp., and to evaluate the coinfection between Wolbachia and Leishmania. Seven hundred and forty-five (745) specimens of sandflies were collected in nine municipalities of Bahia, belonging to two species, Lutzomyia longipalpis (Lutz and Neiva, 1912) and Nyssomyia whitmani (Antunes and Coutinho, 1939). The results confirm infection by the protozoan Leishmania infantum and Wolbachia in both species collected. The identified strain of Wolbachia in sandflies was wStv MI, known to lead to a phenotype of cytoplasmic incompatibility in vector insects.


Subject(s)
Leishmania infantum , Leishmaniasis , Parasites , Psychodidae , Wolbachia , Animals , Brazil , Insect Vectors/parasitology , Leishmania infantum/genetics , Psychodidae/parasitology , Wolbachia/genetics
11.
J Med Entomol ; 59(5): 1831-1836, 2022 Sep 14.
Article in English | MEDLINE | ID: mdl-35849008

ABSTRACT

Recently, the endobacteria Wolbachia has emerged as a biological tool for the control of arboviruses. Thus, we investigated the rate of natural infection by Wolbachia in Culicidae species from Maranhão, Brazil. For this, we amplified the Wolbachia surface protein gene (wsp) from mosquitoes collected in six localities of Maranhão, and positive samples were subjected to new analysis using group-specific primers. In total, 448 specimens comprising 6 genera and 18 species of mosquitoes were analyzed. Wolbachia DNA was PCR-detected in 7 species, three of which are new records: Aedes scapularis (Rondani, 1848), Coquillettidia juxtamansonia (Chagas, 1907) and Cq. venezuelensis (Theobald, 1912), in addition to Ae. albopictus (Skuse, 1894) and Culex quinquefasciatus Say, 1823, which are commonly described as permissive to maintain this bacterium in natural environments, and two species of the subgenera Anopheles (Nyssorhynchus) Blanchard, 1902 and Culex (Melanoconion) Theobald, 1903 which could not be identified at species level. The infection rate of all species ranged from 0 to 80%, and the average value was 16.5%. This study increases the knowledge about the prevalence of Wolbachia in the culicid fauna and may help in selecting strains for biological control purposes.


Subject(s)
Aedes , Anopheles , Culex , Culicidae , Wolbachia , Aedes/microbiology , Animals , Anopheles/microbiology , Brazil , Culex/microbiology , Culicidae/microbiology
12.
PLoS One ; 17(7): e0263143, 2022.
Article in English | MEDLINE | ID: mdl-35895627

ABSTRACT

Aedes spp. comprise the primary group of mosquitoes that transmit arboviruses such as dengue, Zika, and chikungunya viruses to humans, and thus these insects pose a significant burden on public health worldwide. Advancements in next-generation sequencing and metagenomics have expanded our knowledge on the richness of RNA viruses harbored by arthropods such as Ae. aegypti and Ae. albopictus. Increasing evidence suggests that vector competence can be modified by the microbiome (comprising both bacteriome and virome) of mosquitoes present in endemic zones. Using an RNA-seq-based metataxonomic approach, this study determined the virome structure, Wolbachia presence and mitochondrial diversity of field-caught Ae. aegypti and Ae. albopictus mosquitoes in Medellín, Colombia, a municipality with a high incidence of mosquito-transmitted arboviruses. The two species are sympatric, but their core viromes differed considerably in richness, diversity, and abundance; although the community of viral species identified was large and complex, the viromes were dominated by few virus species. BLAST searches of assembled contigs suggested that at least 17 virus species (16 of which are insect-specific viruses [ISVs]) infect the Ae. aegypti population. Dengue virus 3 was detected in one sample and it was the only pathogenic virus detected. In Ae. albopictus, up to 11 ISVs and one plant virus were detected. Therefore, the virome composition appears to be species-specific. The bacterial endosymbiont Wolbachia was identified in all Ae. albopictus samples and in some Ae. aegypti samples collected after 2017. The presence of Wolbachia sp. in Ae. aegypti was not related to significant changes in the richness, diversity, or abundance of this mosquito's virome, although it was related to an increase in the abundance of Aedes aegypti To virus 2 (Metaviridae). The mitochondrial diversity of these mosquitoes suggested that the Ae. aegypti population underwent a change that started in the second half of 2017, which coincides with the release of Wolbachia-infected mosquitoes in Medellín, indicating that the population of wMel-infected mosquitoes released has introduced new alleles into the wild Ae. aegypti population of Medellín. However, additional studies are required on the dispersal speed and intergenerational stability of wMel in Medellín and nearby areas as well as on the introgression of genetic variants in the native mosquito population.


Subject(s)
Aedes , Insect Viruses , RNA Viruses , Viruses , Wolbachia , Zika Virus Infection , Zika Virus , Animals , Colombia , Humans , Insect Viruses/genetics , Mosquito Vectors , Virome/genetics , Viruses/genetics , Wolbachia/genetics
13.
BMC Res Notes ; 15(1): 240, 2022 Jul 07.
Article in English | MEDLINE | ID: mdl-35799282

ABSTRACT

OBJECTIVES: Environmental constraints, especially temperature, have been identified as a key in understanding host-symbiont relationships, as they can directly impact the fitness of the symbiont population and the host development. Here we investigated the effect of temperature during the host development on the density of intracellular bacteria of the Wolbachia, wTcon strain within the confused flour beetle, Tribolium confusum. The wTcon can induce a complete cytoplasmic incompatibility (CI) in T. confusum beetles; therefore, we observed the effect of heat stress on the symbiont-mediated CI. RESULTS: The density of CI inducing Wolbachia in the Tribolium confusum is temperature-specific. Our observation of the beetles reared in five different temperatures (30-34 °C) measured the highest Wolbachia density at 30-31 °C and lowest at 34 °C within a single insect generation. In this species, changes in the density of Wolbachia related to higher temperature did not influence CI. However, the fertility of beetles reared in higher temperatures showed a substantial decrease in the number of laid and hatched eggs. Thus, we can confirm the effect of high temperature on lowering the wTcon density and no impact on induction of cytoplasmic incompatibility (CI) in T. confusum beetles.


Subject(s)
Coleoptera , Tribolium , Wolbachia , Animals , Cytoplasm , Temperature
14.
Front Cell Infect Microbiol ; 12: 900608, 2022.
Article in English | MEDLINE | ID: mdl-35873163

ABSTRACT

Zika is a vector-borne disease caused by an arbovirus (ZIKV) and overwhelmingly transmitted by Ae. aegypti. This disease is linked to adverse fetal outcomes, mostly microcephaly in newborns, and other clinical aspects such as acute febrile illness and neurologic complications, for example, Guillain-Barré syndrome. One of the most promising strategies to mitigate arbovirus transmission involves releasing Ae. aegypti mosquitoes carrying the maternally inherited endosymbiont bacteria Wolbachia pipientis. The presence of Wolbachia is associated with a reduced susceptibility to arboviruses and a fitness cost in mosquito life-history traits such as fecundity and fertility. However, the mechanisms by which Wolbachia influences metabolic pathways leading to differences in egg production remains poorly known. To investigate the impact of coinfections on the reproductive tract of the mosquito, we applied an isobaric labeling-based quantitative proteomic strategy to investigate the influence of Wolbachia wMel and ZIKV infection in Ae. aegypti ovaries. To the best of our knowledge, this is the most complete proteome of Ae. aegypti ovaries reported so far, with a total of 3913 proteins identified, were also able to quantify 1044 Wolbachia proteins in complex sample tissue of Ae. aegypti ovary. Furthermore, from a total of 480 mosquito proteins modulated in our study, we discuss proteins and pathways altered in Ae. aegypti during ZIKV infections, Wolbachia infections, coinfection Wolbachia/ZIKV, and compared with no infection, focusing on immune and reproductive aspects of Ae. aegypti. The modified aspects mainly were related to the immune priming enhancement by Wolbachia presence and the modulation of the Juvenile Hormone pathway caused by both microorganism's infection.


Subject(s)
Aedes , Coinfection , Wolbachia , Zika Virus Infection , Zika Virus , Aedes/microbiology , Animals , Female , Humans , Infant, Newborn , Mosquito Vectors , Ovary , Proteomics
15.
Med Vet Entomol ; 36(3): 301-308, 2022 09.
Article in English | MEDLINE | ID: mdl-35876244

ABSTRACT

The endosymbiont Wolbachia can have major effects on the reproductive fitness, and vectorial capacity of host insects and may provide new avenues to control mosquito-borne pathogens. Anopheles gambiae s.l is the major vector of malaria in Africa but the use of Wolbachia in this species has been limited by challenges in establishing stable transinfected lines and uncertainty around native infections. High frequencies of infection of Wolbachia have been previously reported in An. gambiae collected from the Valle du Kou region of Burkina Faso in 2011 and 2014. Here, we re-evaluated the occurrence of Wolbachia in natural samples, collected from Valle du Kou over a 12-year time span, and in addition, expanded sampling to other sites in Burkina Faso. Our results showed that, in contrast to earlier reports, Wolbachia is present at an extremely low prevalence in natural population of An. gambiae. From 5341 samples analysed, only 29 were positive for Wolbachia by nested PCR representing 0.54% of prevalence. No positive samples were found with regular PCR. Phylogenetic analysis of 16S rRNA gene amplicons clustered across supergroup B, with some having similarity to sequences previously found in Anopheles from Burkina Faso. However, we cannot discount the possibility that the amplicon positive samples we detected were due to environmental contamination or were false positives. Regardless, the lack of a prominent native infection in An. gambiae s.l. is encouraging for applications utilizing Wolbachia transinfected mosquitoes for malaria control.


Subject(s)
Anopheles , Malaria , Wolbachia , Animals , Anopheles/genetics , Burkina Faso , Malaria/veterinary , Mosquito Vectors , Phylogeny , RNA, Ribosomal, 16S/genetics , Wolbachia/genetics
16.
mBio ; 13(4): e0118222, 2022 Aug 30.
Article in English | MEDLINE | ID: mdl-35862784

ABSTRACT

Wolbachia is a heritable alphaproteobacterial symbiont of arthropods and nematodes, famous for its repertoire of host manipulations, including cytoplasmic incompatibility. To be vertically transmitted, Wolbachia must efficiently colonize the female germ line, although somatic tissues outside the gonads are also infected. In Drosophila spp., Wolbachia is usually distributed systemically in multiple regions of the adult fly, but in some neotropical hosts, Wolbachia's only somatic niches are cerebral bacteriocyte-like structures and the ovarian follicle cells. In their recent article, Strunov and colleagues (A. Strunov, K. Schmidt, M. Kapun, and W. J. Miller. mBio 13:e03863-21, 2022, https://doi.org/10.1128/mbio.03863-21) compared the development of Drosophila spp. with systemic or restricted infections and demonstrated that the restricted pattern is determined in early embryogenesis by an apparently novel autophagic process, involving intimate interactions of Wolbachia with the endoplasmic reticulum. This work has implications not only for the evolution of neotropical Drosophila spp. but also for our understanding of how Wolbachia infections are controlled in other native or artificial hosts.


Subject(s)
Nematoda , Wolbachia , Animals , Brain , Drosophila/microbiology , Female , Symbiosis
17.
PLoS Negl Trop Dis ; 16(6): e0010474, 2022 06.
Article in English | MEDLINE | ID: mdl-35671324

ABSTRACT

The development of new drugs targeting adult-stage lymphatic filarial nematodes is hindered by the lack of a robust long-term in vitro culture model. Testing potential direct-acting and anti-Wolbachia therapeutic candidates against adult lymphatic filariae in vitro requires their propagation via chronic infection of gerbils. We evaluated Brugia malayi parasite burden data from male Mongolian gerbils compared with two immune-deficient mouse strains highly susceptible to B. malayi: CB.17 Severe-Combined Immmuno-Deficient (SCID) and interleukin-4 receptor alpha, interleukin-5 double knockout (IL-4Rα-/-IL-5-/-) mice. Adult worms generated in IL-4Rα-/-IL-5-/- mice were tested with different feeder cells (human embryonic kidney cells, human adult dermal lymphatic endothelial cells and human THP-1 monocyte differentiated macrophages) and comparative cell-free conditions to optimise and validate a long-term in vitro culture system. Cultured parasites were compared against those isolated from mice using motility scoring, metabolic viability assay (MTT), ex vivo microfilariae release assay and Wolbachia content by qPCR. A selected culture system was validated as a drug screen using reference anti-Wolbachia (doxycycline, ABBV-4083 / flubentylosin) or direct-acting compounds (flubendazole, suramin). BALB/c IL-4Rα-/-IL-5-/- or CB.17 SCID mice were superior to Mongolian gerbils in generating adult worms and supporting in vivo persistence for periods of up to 52 weeks. Adult females retrieved from BALB/c IL-4Rα-/-IL-5-/- mice could be cultured for up to 21 days in the presence of a lymphatic endothelial cell co-culture system with comparable motility, metabolic activity and Wolbachia titres to those maintained in vivo. Drug studies confirmed significant Wolbachia depletions or direct macrofilaricidal activities could be discerned when female B. malayi were cultured for 14 days. We therefore demonstrate a novel methodology to generate adult B. malayi in vivo and accurately evaluate drug efficacy ex vivo which may be adopted for drug screening with the dual benefit of reducing overall animal use and improving anti-filarial drug development.


Subject(s)
Brugia malayi , Wolbachia , Animals , Coculture Techniques , Disease Models, Animal , Endothelial Cells , Endothelium, Lymphatic , Female , Interleukin-5 , Male , Mice , Mice, Inbred BALB C
18.
Arch Microbiol ; 204(7): 376, 2022 Jun 09.
Article in English | MEDLINE | ID: mdl-35678877

ABSTRACT

The number of arbovirus cases has increased in recent years, demonstrating a need for investing in effective control actions. Among these actions, are strategies using biological control vectors, a field where Wolbachia pipientis has shown itself as useful. Wolbachia pipientis, an obligatory intracellular Gram-negative bacteria, which parasites arthropods naturally or through laboratory-induced infections, is capable of manipulating the reproduction of its host. A systematic literature review gathering studies on this bacteria over last 10 years (2007-2021) was performed given its important role in the reduction of insect disease vectors. 111 articles were found, from which 78 were used in this study. Information on the Wolbachia biology, mechanism of action and potential for the biological control of insect disease vectors was gathered. The present study may contribute to the knowledge surrounding the bacterium, as well as stimulate the production of other studies with the same theme.


Subject(s)
Arboviruses , Wolbachia , Animals , Insect Vectors/microbiology
19.
Parasit Vectors ; 15(1): 221, 2022 Jun 21.
Article in English | MEDLINE | ID: mdl-35729601

ABSTRACT

BACKGROUND: ICMR-Vector Control Research Centre, Puducherry, India, developed two colonies of Aedes aegypti infected with wMel and wAlbB Wolbacia strains called Ae. aegypti (Pud) lines for dengue control. The sensitivity of wMel and wAlbB strains in Ae. aegypti (Pud) lines to heat stress was studied. METHODS: wMel and wAlbB infected and uninfected Ae. aegypti larvae (first to fourth instars) were reared in the laboratory to adults at 26 °C, 30 °C, 36 °C and 40 °C constant temperatures and also 26-30 °C, 26-36 °C and 26-40 °C diurnal cyclic temperatures. The adults were tested for Wolbachia infection. Experiments were also carried out rearing the larvae under simulated field conditions in summer (April and June) under sunlight using fully open and half open bowls and also under sunlight and natural shade. RESULTS: At 36 °C and 40 °C constant temperatures, complete larval mortality was observed. At 30 °C and 26 °C, no larval mortality occurred, but Wolbachia density was relatively low in wMel infected males compared to control (maintained at 26 ± 1 °C). At diurnal cyclic temperature of 26-40 °C, Wolbachia density was reduced in males of both the (Pud) lines, but not in females. At 26-36 °C, reduction in Wolbachia density was observed in wMel males but not in wAlbB males. At 26-30 °C, no significant reduction in Wolbachia density was observed with wMel and wAlbB strains. In simulated field conditions (April), under sunlight, the daytime water temperature reached a maximum of 35.7 °C in both full and half open bowls. No larval mortality occurred. Wolbachia frequency and density was reduced in wMel-infected Ae. aegypti (Pud) males from both type of bowls and in females from full open bowls, and in wAlbB males from half open bowls. In June, rearing of larvae under sunlight, the first-instar larvae experienced a maximum daytime water temperature of > 38 °C that caused complete mortality. No larval mortality was observed in bowls kept under shade (< 32 °C). CONCLUSIONS: Exposure of larvae to higher rearing temperatures in the laboratory and simulated-field conditions reduced the densities of wMel and wAlbB strains particularly in males, but the impact was more pronounced for wMel strain. The actual effect of heat stress on the stability of these two Wolbachia strains needs to be tested under natural field conditions.


Subject(s)
Aedes , Wolbachia , Animals , Female , Heat-Shock Response , Larva , Male , Mosquito Vectors , Water
20.
PLoS Genet ; 18(6): e1010227, 2022 06.
Article in English | MEDLINE | ID: mdl-35666732

ABSTRACT

Wolbachia are the most common obligate, intracellular bacteria in animals. They exist worldwide in arthropod and nematode hosts in which they commonly act as reproductive parasites or mutualists, respectively. Bacteriophage WO, the largest of Wolbachia's mobile elements, includes reproductive parasitism genes, serves as a hotspot for genetic divergence and genomic rearrangement of the bacterial chromosome, and uniquely encodes a Eukaryotic Association Module with eukaryotic-like genes and an ensemble of putative host interaction genes. Despite WO's relevance to genome evolution, selfish genetics, and symbiotic applications, relatively little is known about its origin, host range, diversification, and taxonomic classification. Here we analyze the most comprehensive set of 150 Wolbachia and phage WO assemblies to provide a framework for discretely organizing and naming integrated phage WO genomes. We demonstrate that WO is principally in arthropod Wolbachia with relatives in diverse endosymbionts and metagenomes, organized into four variants related by gene synteny, often oriented opposite the putative origin of replication in the Wolbachia chromosome, and the large serine recombinase is an ideal typing tool to distinguish the four variants. We identify a novel, putative lytic cassette and WO's association with a conserved eleven gene island, termed Undecim Cluster, that is enriched with virulence-like genes. Finally, we evaluate WO-like Islands in the Wolbachia genome and discuss a new model in which Octomom, a notable WO-like Island, arose from a split with WO. Together, these findings establish the first comprehensive Linnaean taxonomic classification of endosymbiont phages, including non-Wolbachia phages from aquatic environments, that includes a new family and two new genera to capture the collective relatedness of these viruses.


Subject(s)
Arthropods , Bacteriophages , Wolbachia , Animals , Bacteriophages/genetics , Eukaryota , Genomics , Symbiosis/genetics , Wolbachia/genetics
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