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Sample records for influential passenger wolbachia

  1. Infection by Wolbachia: from passengers to residents.

    PubMed

    Merçot, Hervé; Poinsot, Denis

    2009-01-01

    Wolbachia are endosymbiotic alpha-proteobacteria harboured by terrestrial arthropods and filarial nematodes, where they are maternally transmitted through egg cytoplasm. According to the host group, Wolbachia have developed two contrasting symbiotic strategies. In arthropods, symbiosis is secondary (i.e. facultative), and Wolbachia insure their transmission as reproduction parasites. However, despite of the efficiency of the manipulation mechanisms used, Wolbachia are limited to the state of passenger because some factors can prevent the association between Wolbachia and their hosts to become permanent. On the contrary, symbiosis is primary (i.e. obligatory) in filarial nematodes where Wolbachia insure their transmission via a mutualistic relationship, leading them to become permanent residents of their hosts. However, a few examples show that in arthropods too some Wolbachia have started to present the first stages of a mutualistic behaviour, or are even truly indispensable to their host. Whatever its strategy, Wolbachia infection is a spectacular evolutionary success, this symbiotic bacterium representing one of the most important biomass of its kind.

  2. Wolbachia Infect Ovaries in the Course of Their Maturation: Last Minute Passengers and Priority Travellers?

    PubMed Central

    Genty, Lise-Marie; Bouchon, Didier; Raimond, Maryline; Bertaux, Joanne

    2014-01-01

    Wolbachia are widespread endosymbiotic bacteria of arthropods and nematodes. Studies on such models suggest that Wolbachia's remarkable aptitude to infect offspring may rely on a re-infection of ovaries from somatic tissues instead of direct cellular segregation between oogonia and oocytes. In the terrestrial isopod Armadillidium vulgare, Wolbachia are vertically transmitted to the host offspring, even though ovary cells are cyclically renewed. Using Fluorescence in situ hybridization (FISH), we showed that the proportion of infected oocytes increased in the course of ovary and oocyte maturation, starting with 31.5% of infected oocytes only. At the end of ovary maturation, this proportion reached 87.6% for the most mature oocytes, which is close to the known transmission rate to offspring. This enrichment can be explained by a secondary acquisition of the bacteria by oocytes (Wolbachia can be seen as last minute passengers) and/or by a preferential selection of oocytes infected with Wolbachia (as priority travellers). PMID:24722673

  3. Species in Wolbachia? Proposal for the designation of 'Candidatus Wolbachia bourtzisii', 'Candidatus Wolbachia onchocercicola', 'Candidatus Wolbachia blaxteri', 'Candidatus Wolbachia brugii', 'Candidatus Wolbachia taylori', 'Candidatus Wolbachia collembolicola' and 'Candidatus Wolbachia multihospitum' for the different species within Wolbachia supergroups.

    PubMed

    Ramírez-Puebla, Shamayim T; Servín-Garcidueñas, Luis E; Ormeño-Orrillo, Ernesto; Vera-Ponce de León, Arturo; Rosenblueth, Mónica; Delaye, Luis; Martínez, Julio; Martínez-Romero, Esperanza

    2015-09-01

    Wolbachia are highly extended bacterial endosymbionts that infect arthropods and filarial nematodes and produce contrasting phenotypes on their hosts. Wolbachia taxonomy has been understudied. Currently, Wolbachia strains are classified into phylogenetic supergroups. Here we applied phylogenomic analyses to study Wolbachia evolutionary relationships and examined metrics derived from their genome sequences such as average nucleotide identity (ANI), in silico DNA-DNA hybridization (DDH), G+C content, and synteny to shed light on the taxonomy of these bacteria. Draft genome sequences of strains wDacA and wDacB obtained from the carmine cochineal insect Dactylopius coccus were included. Although all analyses indicated that each Wolbachia supergroup represents a distinct evolutionary lineage, we found that some of the analyzed supergroups showed enough internal heterogeneity to be considered as assemblages of more than one species. Thus, supergroups would represent supraspecific groupings. Consequently, Wolbachia pipientis nomen species would apply only to strains of supergroup B and we propose the designation of 'Candidatus Wolbachia bourtzisii', 'Candidatus Wolbachia onchocercicola', 'Candidatus Wolbachia blaxterii', 'Candidatus Wolbachia brugii', 'Candidatus Wolbachia taylorii', 'Candidatus Wolbachia collembolicola' and 'Candidatus Wolbachia multihospitis' for other supergroups. Copyright © 2015 Elsevier GmbH. All rights reserved.

  4. "Disproportionately Influential?"

    ERIC Educational Resources Information Center

    Stuart, Reginald

    2010-01-01

    This article discusses why the Lumina Foundation is considered so influential in higher education despite its small size and the fact that is is a relatively new foundation. Lumina approaches its 10th anniversary this month with a focused higher education funding mission targeting efforts aimed at expanding access and success beyond high school,…

  5. "Disproportionately Influential?"

    ERIC Educational Resources Information Center

    Stuart, Reginald

    2010-01-01

    This article discusses why the Lumina Foundation is considered so influential in higher education despite its small size and the fact that is is a relatively new foundation. Lumina approaches its 10th anniversary this month with a focused higher education funding mission targeting efforts aimed at expanding access and success beyond high school,…

  6. Evidence for common horizontal transmission of Wolbachia among butterflies and moths.

    PubMed

    Ahmed, Muhammad Z; Breinholt, Jesse W; Kawahara, Akito Y

    2016-05-27

    Wolbachia is one of the most widespread bacteria on Earth. Previous research on Wolbachia-host interactions indicates that the bacterium is typically transferred vertically, from mother to offspring, through the egg cytoplasm. Although horizontal transmission of Wolbachia from one species to another is reported to be common in arthropods, limited direct ecological evidence is available. In this study, we examine horizontal transmission of Wolbachia using a multilocus sequence typing (MLST) strains dataset and used Wolbachia and Lepidoptera genomes to search for evidence for lateral gene transfer (LGT) in Lepidoptera, one of the most diverse cosmopolitan insect orders. We constructed a phylogeny of arthropod-associated MLST Wolbachia strains and calibrated the age of Wolbachia strains associated with lepidopteran species. Our results reveal inter-specific, inter-generic, inter-familial, and inter-ordinal horizontal transmission of Wolbachia strains, without discernible geographic patterns. We found at least seven probable cases of horizontal transmission among 31 species within Lepidoptera and between Lepidoptera and other arthropod hosts. The divergence time analysis revealed that Wolbachia is recently (22.6-4.7 mya, 95 % HPD) introduced in Lepidoptera. Analysis of nine Lepidoptera genomes (Bombyx mori, Danaus plexippus, Heliconius melpomene, Manduca sexta, Melitaea cinxia, Papilio glaucus, P. polytes, P. xuthus and Plutella xylostella) yielded one possible instance of Wolbachia LGT. Our results provide evidence of high incidence of identical and multiple strains of Wolbachia among butterflies and moths, adding Lepidoptera to the growing body of evidence for common horizontal transmission of Wolbachia. This study demonstrates interesting dynamics of this remarkable and influential microorganism.

  7. Wolbachia versus dengue

    PubMed Central

    Bull, James J.; Turelli, Michael

    2013-01-01

    A novel form of biological control is being applied to the dengue virus. The agent is the maternally transmitted bacterium Wolbachia, naturally absent from the main dengue vector, the mosquito Aedes aegypti. Three Wolbachia-based control strategies have been proposed. One is suppression of mosquito populations by large-scale releases of males incompatible with native females; this intervention requires ongoing releases. The other interventions transform wild mosquito populations with Wolbachia that spread via the frequency-dependent fitness advantage of Wolbachia-infected females; those interventions potentially require just a single, local release for area-wide disease control. One of these latter strategies uses Wolbachia that shortens mosquito life, indirectly preventing viral maturation/transmission. The other strategy uses Wolbachia that block viral transmission. All interventions can be undermined by viral, bacterial or mosquito evolution; viral virulence in humans may also evolve. We examine existing theory, experiments and comparative evidence to motivate predictions about evolutionary outcomes. (i) The life-shortening strategy seems the most likely to be thwarted by evolution. (ii) Mosquito suppression has a reasonable chance of working locally, at least in the short term, but long-term success over large areas is challenging. (iii) Dengue blocking faces strong selection for viral resistance but may well persist indefinitely at some level. Virulence evolution is not mathematically predictable, but comparative data provide no precedent for Wolbachia increasing dengue virulence. On balance, our analysis suggests that the considerable possible benefits of these technologies outweigh the known negatives, but the actual risk is largely unknown. PMID:24481199

  8. Filarial and Wolbachia genomics

    PubMed Central

    SCOTT, A. L.; GHEDIN, E.; NUTMAN, T. B.; McREYNOLDS, L. A.; POOLE, C. B.; SLATKO, B. E.; FOSTER, J. M.

    2012-01-01

    SUMMARY Filarial nematode parasites, the causative agents for a spectrum of acute and chronic diseases including lymphatic filariasis and river blindness, threaten the well-being and livelihood of hundreds of millions of people in the developing regions of the world. The 2007 publication on a draft assembly of the 95-Mb genome of the human filarial parasite Brugia malayi – representing the first helminth parasite genome to be sequenced – has been followed in rapid succession by projects that have resulted in the genome sequencing of six additional filarial species, seven nonfilarial nematode parasites of animals and nearly 30 plant parasitic and free-living species. Parallel to the genomic sequencing, transcriptomic and proteomic projects have facilitated genome annotation, expanded our understanding of stage-associated gene expression and provided a first look at the role of epigenetic regulation of filarial genomes through microRNAs. The expansion in filarial genomics will also provide a significant enrichment in our knowledge of the diversity and variability in the genomes of the endosymbiotic bacterium Wolbachia leading to a better understanding of the genetic principles that govern filarial–Wolbachia mutualism. The goal here is to provide an overview of the trends and advances in filarial and Wolbachia genomics. PMID:22098559

  9. Wolbachia modulates Chikungunya replication in Aedes albopictus.

    PubMed

    Mousson, L; Martin, E; Zouache, K; Madec, Y; Mavingui, P; Failloux, A B

    2010-05-01

    The Aedes albopictus mosquito has been involved as the principal vector of recent major outbreaks due to the chikungunya virus (CHIKV). The species is naturally infected by two strains of Wolbachia (wAlbA and wAlbB). Wolbachia infections are thought to have spread by manipulating the reproduction of their hosts; cytoplasmic incompatibility is the mechanism used by Wolbachia to invade natural populations of many insects including Ae. albopictus. Here, we report a study on the effects of removing Wolbachia from Ae. albopictus on CHIKV replication and examine the consequences of CHIKV infection on some life-history traits (survival and reproduction) of Wolbachia-free Ae. albopictus. We found that Wolbachia-free mosquitoes maintained a highly heterogeneous CHIKV replication compared to Wolbachia-infected individuals. In Wolbachia-infected Ae. albopictus, the regular increase of CHIKV followed by a steady viral load from day 4 post-infection onwards was concomitant with a decline in Wolbachia density. This profile was also detected when examining the two key organs for viral transmission, the midgut and the salivary glands. Moreover, Wolbachia-free Ae. albopictus was not altered in life-history traits such as survival, oviposition and hatching characteristics whether infected or not with CHIKV. We found that Wolbachia is not essential for viral replication, its presence could lead to optimize replication from day 4 post-infection onwards, coinciding with a decrease in Wolbachia density. Wolbachia may regulate viral replication in Ae. albopictus, with consequences on survival and reproduction.

  10. The rich somatic life of Wolbachia.

    PubMed

    Pietri, Jose E; DeBruhl, Heather; Sullivan, William

    2016-12-01

    Wolbachia is an intracellular endosymbiont infecting most arthropod and some filarial nematode species that is vertically transmitted through the maternal lineage. Due to this primary mechanism of transmission, most studies have focused on Wolbachia interactions with the host germline. However, over the last decade many studies have emerged highlighting the prominence of Wolbachia in somatic tissues, implicating somatic tissue tropism as an important aspect of the life history of this endosymbiont. Here, we review our current understanding of Wolbachia-host interactions at both the cellular and organismal level, with a focus on Wolbachia in somatic tissues. © 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  11. Most influential FEMS publications.

    PubMed

    Prosser, James I; Cole, Jeff A; Nielsen, Jens; Bavoil, Patrik M; Häggblom, Max M

    2014-05-01

    A selection of influential FEMS publications to celebrate the 40th anniversary of FEMS. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  12. Uncovering Wolbachia diversity upon artificial host transfer.

    PubMed

    Schneider, Daniela I; Riegler, Markus; Arthofer, Wolfgang; Merçot, Hervé; Stauffer, Christian; Miller, Wolfgang J

    2013-01-01

    The common endosymbiotic Wolbachia bacteria influence arthropod hosts in multiple ways. They are mostly recognized for their manipulations of host reproduction, yet, more recent studies demonstrate that Wolbachia also impact host behavior, metabolic pathways and immunity. Besides their biological and evolutionary roles, Wolbachia are new potential biological control agents for pest and vector management. Importantly, Wolbachia-based control strategies require controlled symbiont transfer between host species and predictable outcomes of novel Wolbachia-host associations. Theoretically, this artificial horizontal transfer could inflict genetic changes within transferred Wolbachia populations. This could be facilitated through de novo mutations in the novel recipient host or changes of haplotype frequencies of polymorphic Wolbachia populations when transferred from donor to recipient hosts. Here we show that Wolbachia resident in the European cherry fruit fly, Rhagoletis cerasi, exhibit ancestral and cryptic sequence polymorphism in three symbiont genes, which are exposed upon microinjection into the new hosts Drosophila simulans and Ceratitis capitata. Our analyses of Wolbachia in microinjected D. simulans over 150 generations after microinjection uncovered infections with multiple Wolbachia strains in trans-infected lines that had previously been typed as single infections. This confirms the persistence of low-titer Wolbachia strains in microinjection experiments that had previously escaped standard detection techniques. Our study demonstrates that infections by multiple Wolbachia strains can shift in prevalence after artificial host transfer driven by either stochastic or selective processes. Trans-infection of Wolbachia can claim fitness costs in new hosts and we speculate that these costs may have driven the shifts of Wolbachia strains that we saw in our model system.

  13. Wolbachia Sequence Typing in Butterflies Using Pyrosequencing.

    PubMed

    Choi, Sungmi; Shin, Su-Kyoung; Jeong, Gilsang; Yi, Hana

    2015-09-01

    Wolbachia is an obligate symbiotic bacteria that is ubiquitous in arthropods, with 25-70% of insect species estimated to be infected. Wolbachia species can interact with their insect hosts in a mutualistic or parasitic manner. Sequence types (ST) of Wolbachia are determined by multilocus sequence typing (MLST) of housekeeping genes. However, there are some limitations to MLST with respect to the generation of clone libraries and the Sanger sequencing method when a host is infected with multiple STs of Wolbachia. To assess the feasibility of massive parallel sequencing, also known as next-generation sequencing, we used pyrosequencing for sequence typing of Wolbachia in butterflies. We collected three species of butterflies (Eurema hecabe, Eurema laeta, and Tongeia fischeri) common to Korea and screened them for Wolbachia STs. We found that T. fischeri was infected with a single ST of Wolbachia, ST41. In contrast, E. hecabe and E. laeta were each infected with two STs of Wolbachia, ST41 and ST40. Our results clearly demonstrate that pyrosequencing-based MLST has a higher sensitivity than cloning and Sanger sequencing methods for the detection of minor alleles. Considering the high prevalence of infection with multiple Wolbachia STs, next-generation sequencing with improved analysis would assist with scaling up approaches to Wolbachia MLST.

  14. Oxidative stress correlates with Wolbachia-mediated antiviral protection in Wolbachia-Drosophila associations.

    PubMed

    Wong, Zhee Sheen; Brownlie, Jeremy C; Johnson, Karyn N

    2015-05-01

    Wolbachia mediates antiviral protection in insect hosts and is being developed as a potential biocontrol agent to reduce the spread of insect-vectored viruses. Definition of the molecular mechanism that generates protection is important for understanding the tripartite interaction between host insect, Wolbachia, and virus. Elevated oxidative stress was previously reported for a mosquito line experimentally infected with Wolbachia, suggesting that oxidative stress is important for Wolbachia-mediated antiviral protection. However, Wolbachia experimentally introduced into mosquitoes impacts a range of host fitness traits, some of which are unrelated to antiviral protection. To explore whether elevated oxidative stress is associated with antiviral protection in Wolbachia-infected insects, we analyzed oxidative stress of five Wolbachia-infected Drosophila lines. In flies infected with protective Wolbachia strains, hydrogen peroxide concentrations were 1.25- to 2-fold higher than those in paired fly lines cured of Wolbachia infection. In contrast, there was no difference in the hydrogen peroxide concentrations in flies infected with nonprotective Wolbachia strains compared to flies cured of Wolbachia infection. Using a Drosophila mutant that produces increased levels of hydrogen peroxide, we investigated whether flies with high levels of endogenous reactive oxygen species had altered responses to virus infection and found that flies with high levels of endogenous hydrogen peroxide were less susceptible to virus-induced mortality. Taken together, these results suggest that elevated oxidative stress correlates with Wolbachia-mediated antiviral protection in natural Drosophila hosts.

  15. 77 FR 27054 - Wolbachia pipientis;

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-08

    ... pesticide of insects/mosquitoes. The Agency has determined that the permit may be of regional and national... release of male Aedes polynesienis mosquitoes infected with Wolbachia pipientis in American Samoa. The male mosquitoes will mate with indigenous female Aedes polynesienis, causing conditional sterility...

  16. Wolbachia spread dynamics in stochastic environments.

    PubMed

    Hu, Linchao; Huang, Mugen; Tang, Moxun; Yu, Jianshe; Zheng, Bo

    2015-12-01

    Dengue fever is a mosquito-borne viral disease with 100 million people infected annually. A novel strategy for dengue control uses the bacterium Wolbachia to invade dengue vector Aedes mosquitoes. As the impact of environmental heterogeneity on Wolbachia spread dynamics in natural areas has been rarely quantified, we develop a model of differential equations for which the environmental conditions switch randomly between two regimes. We find some striking phenomena that random regime transitions could drive Wolbachia to extinction from certain initial states confirmed Wolbachia fixation in homogeneous environments, and mosquito releasing facilitates Wolbachia invasion more effectively when the regimes transit frequently. By superimposing the phase spaces of the ODE systems defined in each regime, we identify the threshold curves below which Wolbachia invades the whole population, which extends the theory of threshold infection frequency to stochastic environments. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Supergroup F Wolbachia bacteria parasitise lice (Insecta: Phthiraptera).

    PubMed

    Covacin, Catherine; Barker, Stephen C

    2007-02-01

    We studied six species of lice from three of the four suborders of lice. These lice were infected with Wolbachia bacteria from supergroups A and F. This is the first report of an infection of supergroup F Wolbachia in lice. To date, Wolbachia from supergroup F have been found in filarial nematodes, Mansonella spp., and, rarely, in insects. We inferred the phylogeny of the Wolbachia from lice and representatives of all Wolbachia supergroups, with nucleotide sequences from the small subunit ribosomal RNA gene (SSU rRNA). There was no evidence of congruence between the taxon of louse and the Wolbachia bacteria that infect lice. There is no evidence that Wolbachia and their louse hosts co-evolved at least at the level of Wolbachia supergroups. We propose a novel mechanism for the horizontal transfer of Wolbachia between different species of lice from birds: transfer of Wolbachia during phoresis by hippoboscid flies.

  18. Do Wolbachia-associated incompatibilities promote polyandry?

    PubMed

    Champion de Crespigny, Fleur E; Hurst, Laurence D; Wedell, Nina

    2008-01-01

    The genetic incompatibility avoidance hypothesis as an explanation for the polyandrous mating strategies (mating with more than one male) of females of many species has received significant attention in recent years. It has received support from both empirical studies and a meta-analysis, which concludes that polyandrous females enjoy increased reproductive success through improved offspring viability relative to monandrous females. In this study we investigate whether polyandrous female Drosophila simulans improve their fitness relative to monandrous females in the face of severe Wolbachia-associated reproductive incompatibilities. We use the results of this study to develop models that test the predictions that Wolbachia should promote polyandry, and that polyandry itself may constrain the spread of Wolbachia. Uniquely, our models allow biologically relevant rates of incompatibility to coevolve with a polyandry modifier allele, which allows us to evaluate the fate of the modifier and that of Wolbachia. Our empirical results reveal that polyandrous females significantly reduce the reproductive costs of Wolbachia, owing to infected males being poor sperm competitors. The models show that this disadvantage in sperm competition can inhibit or prevent the invasion of Wolbachia. However, despite the increased reproductive success obtained by polyandrous females, the spread of a polyandry modifier allele is constrained by any costs that might be associated with polyandry and the low frequency of incompatible matings when Wolbachia has reached a stable equilibrium. Therefore, although incompatibility avoidance may be a benefit of polyandry, our findings do not support the hypothesis that genetic incompatibilities caused by Wolbachia promote the evolution of polyandry.

  19. Wolbachia Biocontrol Strategies for Arboviral Diseases and the Potential Influence of Resident Wolbachia Strains in Mosquitoes.

    PubMed

    Jeffries, Claire L; Walker, Thomas

    Arboviruses transmitted by mosquitoes are a major cause of human disease worldwide. The absence of vaccines and effective vector control strategies has resulted in the need for novel mosquito control strategies. The endosymbiotic bacterium Wolbachia has been proposed to form the basis for an effective mosquito biocontrol strategy. Resident strains of Wolbachia inhibit viral replication in Drosophila fruit flies and induce a reproductive phenotype known as cytoplasmic incompatibility that allows rapid invasion of insect populations. Transinfection of Wolbachia strains into the principle mosquito vector of dengue virus, Stegomyia aegypti, has resulted in dengue-refractory mosquito lines with minimal effects on mosquito fitness. Wolbachia strains have now been established in wild St. aegypti populations through open releases in dengue-endemic countries. In this review, we outline the current state of Wolbachia-based biocontrol strategies for dengue and discuss the potential impact of resident Wolbachia strains for additional target mosquito species that transmit arboviruses.

  20. Wolbachia endosymbionts and human disease control.

    PubMed

    Slatko, Barton E; Luck, Ashley N; Dobson, Stephen L; Foster, Jeremy M

    2014-07-01

    Most human filarial nematode parasites and arthropods are hosts for a bacterial endosymbiont, Wolbachia. In filaria, Wolbachia are required for normal development, fertility and survival, whereas in arthropods, they are largely parasitic and can influence development and reproduction, but are generally not required for host survival. Due to their obligate nature in filarial parasites, Wolbachia have been a target for drug discovery initiatives using several approaches including diversity and focused library screening and genomic sequence analysis. In vitro and in vivo anti-Wolbachia antibiotic treatments have been shown to have adulticidal activity, a long sought goal of filarial parasite drug discovery. In mosquitoes, it has been shown that the presence of Wolbachia can inhibit the transmission of certain viruses, such as Dengue, Chikungunya, Yellow Fever, West Nile, as well as the infectivity of the malaria-causing protozoan, Plasmodium and filarial nematodes. Furthermore, Wolbachia can cause a form of conditional sterility that can be used to suppress populations of mosquitoes and additional medically important insects. Thus Wolbachia, a pandemic endosymbiont offers great potential for elimination of a wide-variety of devastating human diseases.

  1. Wolbachia in Anastrepha fruit flies (Diptera: Tephritidae).

    PubMed

    Coscrato, Virginia E; Braz, Antônio S K; P Perondini, André L; Selivon, Denise; Marino, Celso L

    2009-09-01

    Endosymbiotic bacteria of the genus Wolbachia are widespread among arthropods and cause a variety of reproductive abnormalities, such as cytoplasmic incompatibility, thelytokous parthenogenesis, male-killing, and host feminization. In this study, we used three sets of Wolbachia-specific primers (16S rDNA, ftsZ, and wsp) in conjunction with the polymerase chain reaction (PCR), cloning and sequencing to study the infection of fruit flies (Anastrepha spp. and Ceratitis capitata) by Wolbachia. The flies were collected at several localities in Brazil and at Guayaquil, Ecuador. All of the fruit flies studied were infected with Wolbachia supergroup A, in agreement with the high prevalence of this group in South America. Phylogenetic analysis showed that the wsp gene was the most sensitive gene for studying the relationships among Wolbachia strains. The Wolbachia sequences detected in these fruit flies were similar to those such as wMel reported for other fruit flies. These results show that the infection of Anastrepha fruit flies by Wolbachia is much more widespread than previously thought.

  2. Iron Necessity: The Secret of Wolbachia's Success?

    PubMed Central

    Gill, Alessandra Christina; Darby, Alistair C.; Makepeace, Benjamin L.

    2014-01-01

    The bacterium Wolbachia (order Rickettsiales) is probably the world's most successful vertically-transmitted symbiont, distributed among a staggering 40% of terrestrial arthropod species. Wolbachia has great potential in vector control due to its ability to manipulate its hosts' reproduction and to impede the replication and dissemination of arboviruses and other pathogens within haematophagous arthropods. In addition, the unexpected presence of Wolbachia in filarial nematodes of medical and veterinary importance has provided an opportunity to target the adult worms of Wuchereria bancrofti, Onchocerca volvulus, and Dirofilaria immitis with safe drugs such as doxycycline. A striking feature of Wolbachia is its phenotypic plasticity between (and sometimes within) hosts, which may be underpinned by its ability to integrate itself into several key processes within eukaryotic cells: oxidative stress, autophagy, and apoptosis. Importantly, despite significant differences in the genomes of arthropod and filarial Wolbachia strains, these nexuses appear to lie on a continuum in different hosts. Here, we consider how iron metabolism may represent a fundamental aspect of host homeostasis that is impacted by Wolbachia infection, connecting disparate pathways ranging from the provision of haem and ATP to programmed cell death, aging, and the recycling of intracellular resources. Depending on how Wolbachia and host cells interact across networks that depend on iron, the gradient between parasitism and mutualism may shift dynamically in some systems, or alternatively, stabilise on one or the other end of the spectrum. PMID:25329055

  3. Deleterious Wolbachia in the ant Formica truncorum.

    PubMed Central

    Wenseleers, T; Sundström, L; Billen, J

    2002-01-01

    Wolbachia is a maternally inherited bacterium that may manipulate the reproduction of its arthropod hosts. In insects, it is known to lead to inviable matings, cause asexual reproduction or kill male offspring, all to its own benefit, but to the detriment of its host. In social Hymenoptera, Wolbachia occurs widely, but little is known about its fitness effects. We report on a Wolbachia infection in the wood ant Formica truncorum, and evaluate whether it influences reproductive patterns. All 33 colonies of the study population were infected, suggesting that Wolbachia infection is at, or close to, fixation. Interestingly, in colonies with fewer infected workers, significantly more sexuals are produced, indicating that Wolbachia has deleterious effects in this species. In addition, adult workers are shown to have significantly lower infection rates (45%) than worker pupae (87%) or virgin queens (94%), suggesting that workers lose their infection over life. Clearance of Wolbachia infection has, to our knowledge, never been shown in any other natural system, but we argue that it may, in this case, represent an adaptive strategy to reduce colony load. The cause of fixation requires further study, but our data strongly suggest that Wolbachia has no influence on the sex ratio in this species. PMID:11916479

  4. Molecular identification of Wolbachia from the filarial nematode Mansonella perstans

    PubMed Central

    Keiser, Paul B.; Coulibaly, Yaya; Kubofcik, Joseph; Diallo, Abdallah A.; Klion, Amy D.; Traoré, Sekou F.; Nutman, Thomas B.

    2008-01-01

    Wolbachiae are bacterial endosymbionts of insects and many filarial nematodes whose products trigger inflammation in filarial infections. The dependence of the parasites on their endosymbionts has also led to the use of antibiotics directed against the Wolbachiae, therapy that has been demonstrated to have a profound salutary effect on filarial infections. The identification of Wolbachiae in Mansonella species has been conclusively shown for Mansonella ozzardi (Mo), but not for Mansonella perstans (Mp) Using primers known to amplify the 16S ribosomal DNA of other filarial Wolbachiae, an identical 1393 bp band was found in all samples tested. Sequence analysis of these samples demonstrated a single consensus sequence for Mp Wolbachia 16S rDNA that was most similar to Wolbachia sequences from other filarial nematodes. When aligned with the only other Mansonella Wolbachia sequence (Mo) there were only 8 nucleotide differences in the 1369 bp overlapping sequence. Phylogenetic dendrograms, showing the relationship of the Mp Wolbachia to other Wolbachia 16S rDNA, tracked almost identically to the 5S rRNA of their parasite host. Wolbachia surface protein (WSP) was also demonstrated in protein extracted from Mp-containing whole blood. In advance of a treatment trial of Mp, a method for the quantitation of Mp Wolbachia was developed and used to demonstrate not only a relationship between microfilarial numbers and Wolbachia copy numbers, but also to demonstrate the effect of antibiotic on ridding Mp of Wolbachia. PMID:18538871

  5. Parthenogenesis induction by Wolbachia in parasitoids

    USDA-ARS?s Scientific Manuscript database

    The maternally inherited intracellular bacterium, Wolbachia pipientis, induces reproductive alterations in host arthropod populations such as male-killing, feminization, parthenogenesis induction (PI, or reproduction without males) and cytoplasmic incompatibility. Here we report that PI in Mexican O...

  6. Mutualism breakdown by amplification of Wolbachia genes.

    PubMed

    Chrostek, Ewa; Teixeira, Luis

    2015-02-01

    Most insect species are associated with vertically transmitted endosymbionts. Because of the mode of transmission, the fitness of these symbionts is dependent on the fitness of the hosts. Therefore, these endosymbionts need to control their proliferation in order to minimize their cost for the host. The genetic bases and mechanisms of this regulation remain largely undetermined. The maternally inherited bacteria of the genus Wolbachia are the most common endosymbionts of insects, providing some of them with fitness benefits. In Drosophila melanogaster, Wolbachia wMelPop is a unique virulent variant that proliferates massively in the hosts and shortens their lifespan. The genetic bases of wMelPop virulence are unknown, and their identification would allow a better understanding of how Wolbachia levels are regulated. Here we show that amplification of a region containing eight Wolbachia genes, called Octomom, is responsible for wMelPop virulence. Using Drosophila lines selected for carrying Wolbachia with different Octomom copy numbers, we demonstrate that the number of Octomom copies determines Wolbachia titers and the strength of the lethal phenotype. Octomom amplification is unstable, and reversion of copy number to one reverts all the phenotypes. Our results provide a link between genotype and phenotype in Wolbachia and identify a genomic region regulating Wolbachia proliferation. We also prove that these bacteria can evolve rapidly. Rapid evolution by changes in gene copy number may be common in endosymbionts with a high number of mobile elements and other repeated regions. Understanding wMelPop pathogenicity and variability also allows researchers to better control and predict the outcome of releasing mosquitoes transinfected with this variant to block human vector-borne diseases. Our results show that transition from a mutualist to a pathogen may occur because of a single genomic change in the endosymbiont. This implies that there must be constant selection on

  7. Mutualism Breakdown by Amplification of Wolbachia Genes

    PubMed Central

    Chrostek, Ewa; Teixeira, Luis

    2015-01-01

    Most insect species are associated with vertically transmitted endosymbionts. Because of the mode of transmission, the fitness of these symbionts is dependent on the fitness of the hosts. Therefore, these endosymbionts need to control their proliferation in order to minimize their cost for the host. The genetic bases and mechanisms of this regulation remain largely undetermined. The maternally inherited bacteria of the genus Wolbachia are the most common endosymbionts of insects, providing some of them with fitness benefits. In Drosophila melanogaster, Wolbachia wMelPop is a unique virulent variant that proliferates massively in the hosts and shortens their lifespan. The genetic bases of wMelPop virulence are unknown, and their identification would allow a better understanding of how Wolbachia levels are regulated. Here we show that amplification of a region containing eight Wolbachia genes, called Octomom, is responsible for wMelPop virulence. Using Drosophila lines selected for carrying Wolbachia with different Octomom copy numbers, we demonstrate that the number of Octomom copies determines Wolbachia titers and the strength of the lethal phenotype. Octomom amplification is unstable, and reversion of copy number to one reverts all the phenotypes. Our results provide a link between genotype and phenotype in Wolbachia and identify a genomic region regulating Wolbachia proliferation. We also prove that these bacteria can evolve rapidly. Rapid evolution by changes in gene copy number may be common in endosymbionts with a high number of mobile elements and other repeated regions. Understanding wMelPop pathogenicity and variability also allows researchers to better control and predict the outcome of releasing mosquitoes transinfected with this variant to block human vector-borne diseases. Our results show that transition from a mutualist to a pathogen may occur because of a single genomic change in the endosymbiont. This implies that there must be constant selection on

  8. Phylogenomic analyses uncover origin and spread of the Wolbachia pandemic.

    PubMed

    Gerth, Michael; Gansauge, Marie-Theres; Weigert, Anne; Bleidorn, Christoph

    2014-10-06

    Of all obligate intracellular bacteria, Wolbachia is probably the most common. In general, Wolbachia are either widespread, opportunistic reproductive parasites of arthropods or essential mutualists in a single group of filarial nematodes, including many species of medical significance. To date, a robust phylogenetic backbone of Wolbachia is lacking and consequently, many Wolbachia-related phenomena cannot be discussed in a broader evolutionary context. Here we present the first comprehensive phylogenomic analysis of Wolbachia supergroup relationships based on new whole-genome-shotgun data. Our results suggest that Wolbachia has switched between its two major host groups at least twice. The ability of some arthropod-infecting Wolbachia to universally infect and to adapt to a broad range of hosts quickly is restricted to a single monophyletic lineage (containing supergroups A and B). Thus, the currently observable pandemic has likely a single evolutionary origin and is unique within the radiation of Wolbachia strains.

  9. Wolbachia-infection differs among potato psyllid haplotypes

    USDA-ARS?s Scientific Manuscript database

    Wolbachia is a bacterial endosymbiont of insects that can manipulate insect reproduction. In many insects, Wolbachia-free females cannot produce viable offspring when mated by infected males. The manipulation of insect reproduction by Wolbachia has important implications for insect evolution and pop...

  10. Evidence for horizontal transfer of Wolbachia by a Drosophila mite.

    PubMed

    Brown, Amy N; Lloyd, Vett K

    2015-07-01

    Mites are common ectoparasites of Drosophila and have been implicated in bacterial and mobile element invasion of Drosophila stocks. The obligate endobacterium, Wolbachia, has widespread effects on gene expression in their arthropod hosts and alters host reproduction to enhance its survival and propagation, often with deleterious effects in Drosophila hosts. To determine whether Wolbachia could be transferred between Drosophila melanogaster laboratory stocks by the mite Tyrophagus putrescentiae, mites were introduced to Wolbachia-infected Drosophila vials. These vials were kept adjacent to mite-free and Wolbachia-uninfected Drosophila stock vials. The Wolbachia infection statuses of the infected and uninfected flies were checked from generation 1 to 5. Results indicate that Wolbachia DNA could be amplified from mites infesting Wolbachia-infected fly stocks and infection in the previously uninfected stocks arose within generation 1 or 2, concomitant with invasion of mites from the Wolbachia-infected stock. A possible mechanism for the transfer of Wolbachia from flies to mites and vice versa, can be inferred from time-lapse photography of fly and mite interactions. We demonstrated that mites ingest Drosophila corpses, including Wolbachia-infected corpses, and Drosophila larva ingest mites, providing possible sources of Wolbachia infection and transfer. This research demonstrated that T. putrescentiae white mites can facilitate Wolbachia transfer between Drosophila stocks and that this may occur by ingestion of infected corpses. Mite-vectored Wolbachia transfer allows for rapid establishment of Wolbachia infection within a new population. This mode of Wolbachia introduction may be relevant in nature as well as in the laboratory, and could have a variety of biological consequences.

  11. A Wolbachia deubiquitylating enzyme induces cytoplasmic incompatibility.

    PubMed

    Beckmann, John F; Ronau, Judith A; Hochstrasser, Mark

    2017-03-01

    Wolbachia are obligate intracellular bacteria(1) that infect arthropods, including approximately two-thirds of insect species(2). Wolbachia manipulate insect reproduction by enhancing their inheritance through the female germline. The most common alteration is cytoplasmic incompatibility (CI)(3-5), where eggs from uninfected females fail to develop when fertilized by sperm from Wolbachia-infected males. By contrast, if female and male partners are both infected, embryos are viable. CI is a gene-drive mechanism impacting population structure(6) and causing reproductive isolation(7), but its molecular mechanism has remained unknown. We show that a Wolbachia deubiquitylating enzyme (DUB) induces CI. The CI-inducing DUB, CidB, cleaves ubiquitin from substrates and is encoded in a two-gene operon, and the other protein, CidA, binds CidB. Binding is strongest between cognate partners in cidA-cidB homologues. In transgenic Drosophila, the cidA-cidB operon mimics CI when sperm introduce it into eggs, and a catalytically inactive DUB does not induce sterility. Toxicity is recapitulated in yeast by CidB alone; this requires DUB activity but is rescued by coexpressed CidA. A paralogous operon involves a putative nuclease (CinB) rather than a DUB. Analogous binding, toxicity and rescue in yeast were observed. These results identify a CI mechanism involving interacting proteins that are secreted into germline cells by Wolbachia, and suggest new methods for insect control.

  12. Wolbachia increases susceptibility to Plasmodium infection in a natural system.

    PubMed

    Zélé, F; Nicot, A; Berthomieu, A; Weill, M; Duron, O; Rivero, A

    2014-03-22

    Current views about the impact of Wolbachia on Plasmodium infections are almost entirely based on data regarding artificially transfected mosquitoes. This work has shown that Wolbachia reduces the intensity of Plasmodium infections in mosquitoes, raising the exciting possibility of using Wolbachia to control or limit the spread of malaria. Whether natural Wolbachia infections have the same parasite-inhibiting properties is not yet clear. Wolbachia-mosquito combinations with a long evolutionary history are, however, key for understanding what may happen with Wolbachia-transfected mosquitoes after several generations of coevolution. We investigate this issue using an entirely natural mosquito-Wolbachia-Plasmodium combination. In contrast to most previous studies, which have been centred on the quantification of the midgut stages of Plasmodium, we obtain a measurement of parasitaemia that relates directly to transmission by following infections to the salivary gland stages. We show that Wolbachia increases the susceptibility of Culex pipiens mosquitoes to Plasmodium relictum, significantly increasing the prevalence of salivary gland stage infections. This effect is independent of the density of Wolbachia in the mosquito. These results suggest that naturally Wolbachia-infected mosquitoes may, in fact, be better vectors of malaria than Wolbachia-free ones.

  13. Wolbachia infection frequencies in insects: evidence of a global equilibrium?

    PubMed Central

    Werren, J H; Windsor, D M

    2000-01-01

    Wolbachia are a group of cytoplasmically inherited bacteria that cause reproduction alterations in arthropods, including parthenogenesis, reproductive incompatibility, feminization of genetic males and male killing. Previous general surveys of insects in Panama and Britain found Wolbachia to be common, occurring in 16-22% of species. Here, using similar polymerase chain reaction methods, we report that 19.3% of a sample of temperate North American insects are infected with Wolbachia, a frequency strikingly similar to frequencies found in two other studies in widely separated locales. The results may indicate a widespread equilibrium of Wolbachia infection frequencies in insects whose maintenance remains to be explained. Alternatively, Wolbachia may be increasing in global insect communities. Within each of the three geographic regions surveyed, Hymenoptera are more frequently infected with A group Wolbachia and Lepidoptera more frequently infected with B group Wolbachia. PMID:10972121

  14. Wolbachia transmission dynamics in Formica wood ants

    PubMed Central

    2008-01-01

    Background The role of Wolbachia endosymbionts in shaping the mitochondrial diversity of their arthropod host depends on the effects they have on host reproduction and on the mode of transmission of the bacteria. We have compared the sequence diversity of wsp (Wolbachia surface protein gene) and the host mtDNA in a group of Formica ant species that have diverged approximately 0.5 million years ago (MYA). The aim was to study the relationship of Wolbachia and its ant hosts in terms of vertical and horizontal transmission of the bacteria. Results All studied ant species were doubly infected with two Wolbachia strains (wFex1 and wFex4) all over their geographical distribution area in Eurasia. The most common haplotypes of these strains were identical with strains previously described from a more distantly related Formica ant, with an estimated divergence time of 3.5 – 4 MYA. Some strain haplotypes were associated to the same or closely related mtDNA haplotypes as expected under vertical transmission. However, in several cases the wsp haplotypes coexisted with distant mtDNA haplotypes, a pattern which is more compatible with horizontal transmission of the bacteria. Conclusion Two lines of evidence suggest that the sharing of Wolbachia strains by all F. rufa species is rather due to horizontal than vertical transmission. First, the fact that endosymbiont strains identical to those of F. rufa ants have been found in another species that diverged 3.5–4 MYA strongly suggests that horizontal transfer can and does occur between Formica ants. Second, the frequent sharing of identical Wolbachia strains by distant mitochondrial lineages within the F. rufa group further shows that horizontal transmission has occurred repeatedly. Nevertheless, our dataset also provides some evidence for longer-term persistence of infection, indicating that Wolbachia infection within this host clade has been shaped by both horizontal and vertical transmission of symbionts. The fact that all

  15. What the passenger contributes to passenger comfort.

    PubMed

    Richards, L G; Jacobson, I D; Kuhlthau, A R

    1978-09-01

    An individual's reaction to a vehicle environment depends not only on the physical inputs but also on the characteristics of the individual. Surveys of airline passengers were conducted on board regularly scheduled commuter flights. Sex of the respondent and attitude toward flying were found to have import nt influences on passenger comfort. Individual differences were also found regarding (1) perceptions of environmental variables, (2) the importance of factors as determinants of comfort, and (3) the ease of and frequency of performing activities in flight.

  16. Gut microbiota in Drosophila melanogaster interacts with Wolbachia but does not contribute to Wolbachia-mediated antiviral protection.

    PubMed

    Ye, Yixin H; Seleznev, Andrei; Flores, Heather A; Woolfit, Megan; McGraw, Elizabeth A

    2017-02-01

    Animals experience near constant infection with microorganisms. A significant proportion of these microbiota reside in the alimentary tract. There is a growing appreciation for the roles gut microbiota play in host biology. The gut microbiota of insects, for example, have been shown to help the host overcome pathogen infection either through direct competition or indirectly by stimulating host immunity. These defenses may also be supplemented by coinfecting maternally inherited microbes such as Wolbachia. The presence of Wolbachia in a host can delay and/or reduce death caused by RNA viruses. Whether the gut microbiota of the host interacts with Wolbachia, or vice versa, the precise role of Wolbachia in antiviral protection is not known. In this study, we used 16S rDNA sequencing to characterise changes in gut microbiota composition in Drosophila melanogaster associated with Wolbachia infection and antibiotic treatment. We subsequently tested whether changes in gut composition via antibiotic treatment altered Wolbachia-mediated antiviral properties. We found that both antibiotics and Wolbachia significantly reduced the biodiversity of the gut microbiota without changing the total microbial load. We also showed that changing the gut microbiota composition with antibiotic treatment enhanced Wolbachia density but did not confer greater antiviral protection against Drosophila C virus to the host. We concluded there are significant interactions between Wolbachia and gut microbiota, but changing gut microbiota composition is not likely to be a means through which Wolbachia conveys antiviral protection to its host.

  17. The Impact of Wolbachia on Virus Infection in Mosquitoes.

    PubMed

    Johnson, Karyn N

    2015-11-04

    Mosquito-borne viruses such as dengue, West Nile and chikungunya viruses cause significant morbidity and mortality in human populations. Since current methods are not sufficient to control disease occurrence, novel methods to control transmission of arboviruses would be beneficial. Recent studies have shown that virus infection and transmission in insects can be impeded by co-infection with the bacterium Wolbachia pipientis. Wolbachia is a maternally inherited endosymbiont that is commonly found in insects, including a number of mosquito vector species. In Drosophila, Wolbachia mediates antiviral protection against a broad range of RNA viruses. This discovery pointed to a potential strategy to interfere with mosquito transmission of arboviruses by artificially infecting mosquitoes with Wolbachia. This review outlines research on the prevalence of Wolbachia in mosquito vector species and the impact of antiviral effects in both naturally and artificially Wolbachia-infected mosquitoes.

  18. The Impact of Wolbachia on Virus Infection in Mosquitoes

    PubMed Central

    Johnson, Karyn N.

    2015-01-01

    Mosquito-borne viruses such as dengue, West Nile and chikungunya viruses cause significant morbidity and mortality in human populations. Since current methods are not sufficient to control disease occurrence, novel methods to control transmission of arboviruses would be beneficial. Recent studies have shown that virus infection and transmission in insects can be impeded by co-infection with the bacterium Wolbachia pipientis. Wolbachia is a maternally inherited endosymbiont that is commonly found in insects, including a number of mosquito vector species. In Drosophila, Wolbachia mediates antiviral protection against a broad range of RNA viruses. This discovery pointed to a potential strategy to interfere with mosquito transmission of arboviruses by artificially infecting mosquitoes with Wolbachia. This review outlines research on the prevalence of Wolbachia in mosquito vector species and the impact of antiviral effects in both naturally and artificially Wolbachia-infected mosquitoes. PMID:26556361

  19. Population Genomics of the Wolbachia Endosymbiont in Drosophila melanogaster

    PubMed Central

    Richardson, Mark F.; Weinert, Lucy A.; Welch, John J.; Linheiro, Raquel S.; Magwire, Michael M.; Jiggins, Francis M.; Bergman, Casey M.

    2012-01-01

    Wolbachia are maternally inherited symbiotic bacteria, commonly found in arthropods, which are able to manipulate the reproduction of their host in order to maximise their transmission. The evolutionary history of endosymbionts like Wolbachia can be revealed by integrating information on infection status in natural populations with patterns of sequence variation in Wolbachia and host mitochondrial genomes. Here we use whole-genome resequencing data from 290 lines of Drosophila melanogaster from North America, Europe, and Africa to predict Wolbachia infection status, estimate relative cytoplasmic genome copy number, and reconstruct Wolbachia and mitochondrial genome sequences. Overall, 63% of Drosophila strains were predicted to be infected with Wolbachia by our in silico analysis pipeline, which shows 99% concordance with infection status determined by diagnostic PCR. Complete Wolbachia and mitochondrial genomes show congruent phylogenies, consistent with strict vertical transmission through the maternal cytoplasm and imperfect transmission of Wolbachia. Bayesian phylogenetic analysis reveals that the most recent common ancestor of all Wolbachia and mitochondrial genomes in D. melanogaster dates to around 8,000 years ago. We find evidence for a recent global replacement of ancestral Wolbachia and mtDNA lineages, but our data suggest that the derived wMel lineage arose several thousand years ago, not in the 20th century as previously proposed. Our data also provide evidence that this global replacement event is incomplete and is likely to be one of several similar incomplete replacement events that have occurred since the out-of-Africa migration that allowed D. melanogaster to colonize worldwide habitats. This study provides a complete genomic analysis of the evolutionary mode and temporal dynamics of the D. melanogaster–Wolbachia symbiosis, as well as important resources for further analyses of the impact of Wolbachia on host biology. PMID:23284297

  20. Distribution and dynamics of Wolbachia infection in Malaysian Aedes albopictus.

    PubMed

    Joanne, Sylvia; Vythilingam, Indra; Yugavathy, Nava; Leong, Cherng-Shii; Wong, Meng-Li; AbuBakar, Sazaly

    2015-08-01

    Wolbachia are maternally transmitted bacteria found in most arthropods and nematodes, but little is known about their distribution and reproductive dynamics in the Malaysian dengue vector Aedes albopictus. In this study, polymerase chain reaction (PCR) was used to determine the presence of Wolbachia from field collected Ae. albopictus from various parts of the country using wsp specific primers. Ae. albopictus had Wolbachia infection ranging from 60 to 100%. No sequence diversity of wsp gene was found within all wAlbA and wAlbB sequences. Our findings suggest that Wolbachia infection amongst the Malaysian Ae. albopictus were not homogenously distributed in all districts in Malaysia. The presence of Wolbachia in different organs of Ae. albopictus was also determined. Wolbachia were only found in the ovaries and midguts of the mosquitoes, while absent in the salivary glands. The effects of Wolbachia on Ae. albopictus fecundity, longevity and egg viability were studied using infected and uninfected colonies. The removal of Wolbachia from Ae. albopictus resulted in reduced fecundity, longevity and egg viability, thus. Wolbachia seem to play a vital role in Ae. albopictus reproductive system.

  1. Wolbachia as a bacteriocyte-associated nutritional mutualist

    PubMed Central

    Hosokawa, Takahiro; Koga, Ryuichi; Kikuchi, Yoshitomo; Meng, Xian-Ying; Fukatsu, Takema

    2009-01-01

    Many insects are dependent on bacterial symbionts that provide essential nutrients (ex. aphid–Buchnera and tsetse–Wiglesworthia associations), wherein the symbionts are harbored in specific cells called bacteriocytes that constitute a symbiotic organ bacteriome. Facultative and parasitic bacterial symbionts like Wolbachia have been regarded as evolutionarily distinct from such obligate nutritional mutualists. However, we discovered that, in the bedbug Cimex lectularius, Wolbachia resides in a bacteriome and appears to be an obligate nutritional mutualist. Two bacterial symbionts, a Wolbachia strain and an unnamed γ-proteobacterium, were identified from different strains of the bedbug. The Wolbachia symbiont was detected from all of the insects examined whereas the γ-proteobacterium was found in a part of them. The Wolbachia symbiont was specifically localized in the bacteriomes and vertically transmitted via the somatic stem cell niche of germalia to oocytes, infecting the incipient symbiotic organ at an early stage of the embryogenesis. Elimination of the Wolbachia symbiont resulted in retarded growth and sterility of the host insect. These deficiencies were rescued by oral supplementation of B vitamins, confirming the essential nutritional role of the symbiont for the host. The estimated genome size of the Wolbachia symbiont was around 1.3 Mb, which was almost equivalent to the genome sizes of parasitic Wolbachia strains of other insects. These results indicate that bacteriocyte-associated nutritional mutualism can evolve from facultative and prevalent microbial associates like Wolbachia, highlighting a previously unknown aspect of the parasitism-mutualism evolutionary continuum. PMID:20080750

  2. Wolbachia increases susceptibility to Plasmodium infection in a natural system

    PubMed Central

    Zélé, F.; Nicot, A.; Berthomieu, A.; Weill, M.; Duron, O.; Rivero, A.

    2014-01-01

    Current views about the impact of Wolbachia on Plasmodium infections are almost entirely based on data regarding artificially transfected mosquitoes. This work has shown that Wolbachia reduces the intensity of Plasmodium infections in mosquitoes, raising the exciting possibility of using Wolbachia to control or limit the spread of malaria. Whether natural Wolbachia infections have the same parasite-inhibiting properties is not yet clear. Wolbachia–mosquito combinations with a long evolutionary history are, however, key for understanding what may happen with Wolbachia-transfected mosquitoes after several generations of coevolution. We investigate this issue using an entirely natural mosquito–Wolbachia–Plasmodium combination. In contrast to most previous studies, which have been centred on the quantification of the midgut stages of Plasmodium, we obtain a measurement of parasitaemia that relates directly to transmission by following infections to the salivary gland stages. We show that Wolbachia increases the susceptibility of Culex pipiens mosquitoes to Plasmodium relictum, significantly increasing the prevalence of salivary gland stage infections. This effect is independent of the density of Wolbachia in the mosquito. These results suggest that naturally Wolbachia-infected mosquitoes may, in fact, be better vectors of malaria than Wolbachia-free ones. PMID:24500167

  3. Wolbachia: can we save lives with a great pandemic?

    PubMed Central

    LePage, Daniel; Bordenstein, Seth

    2013-01-01

    Wolbachia pipientis is the most common bacterial infection in the animal world and wields a vast influence on invertebrate reproduction, sex determination, speciation, and behavior worldwide. These avenues of research have made seminal gains, including the latest use of Wolbachia to alter mosquito populations and a strengthened focus on using anti-Wolbachia therapies against filarial nematode infections. This work is further bolstered by a more refined knowledge of Wolbachia biology spanning mechanisms to relevance. Here we tally the most up-to-date knowledge in the field and review the immense implications that this global infection has for the basic and applied life sciences. PMID:23845310

  4. Passengers in containers

    NASA Technical Reports Server (NTRS)

    Tarkhanovskiy, V.

    1977-01-01

    A futuristic vision of future passenger and cargo transport is presented. To speed up lengthy transit operations, passengers would be accomodated in comfortable, compartment-like containers. Several diagrams show how such containers can be accomodated aboard an aircraft or a helicopter, on a truck, or in a railroad car. A system would result in great economy in both cost and time. Of particular importance is such a system for cargo traffic.

  5. A feedback loop between Wolbachia and the Drosophila gurken mRNP complex influences Wolbachia titer

    PubMed Central

    Serbus, Laura R.; Ferreccio, Amy; Zhukova, Mariya; McMorris, Chanel L.; Kiseleva, Elena; Sullivan, William

    2011-01-01

    Although much is known about interactions between bacterial endosymbionts and their hosts, little is known concerning the host factors that influence endosymbiont titer. Wolbachia endosymbionts are globally dispersed throughout most insect species and are the causative agent in filarial nematode-mediated disease. Our investigation indicates that gurken (grk), a host gene encoding a crucial axis determinant, has a cumulative, dosage-sensitive impact on Wolbachia growth and proliferation during Drosophila oogenesis. This effect appears to be mediated by grk mRNA and its protein-binding partners Squid and Hrp48/Hrb27C, implicating the grk mRNA–protein (mRNP) complex as a rate-limiting host factor controlling Wolbachia titer. Furthermore, highly infected flies exhibit defects that match those occurring with disruption of grk mRNPs, such as nurse cell chromatin disruptions and malformation of chorionic appendages. These findings suggest a feedback loop in which Wolbachia interaction with the grk mRNP affects both Wolbachia titer and grk mRNP function. PMID:22193955

  6. Closely related Wolbachia recovered from different genera of Mexican Thelytokous figitidae (Hymenoptera)

    USDA-ARS?s Scientific Manuscript database

    Closely related novel Wolbachia strains were recovered from the thelytokous figitids Odontosema anastrephae Borgmeier and Aganaspis alujai Ovruski et al. No Wolbachia were detected in a bi-sexual strain of O. anastrephae. While the presence or absence of Wolbachia does not demonstrate that Wolbachia...

  7. Wolbachia and DNA Barcoding Insects: Patterns, Potential, and Problems

    PubMed Central

    Smith, M. Alex; Bertrand, Claudia; Crosby, Kate; Eveleigh, Eldon S.; Fernandez-Triana, Jose; Fisher, Brian L.; Gibbs, Jason; Hajibabaei, Mehrdad; Hallwachs, Winnie; Hind, Katharine; Hrcek, Jan; Huang, Da-Wei; Janda, Milan; Janzen, Daniel H.; Li, Yanwei; Miller, Scott E.; Packer, Laurence; Quicke, Donald; Ratnasingham, Sujeevan; Rodriguez, Josephine; Rougerie, Rodolphe; Shaw, Mark R.; Sheffield, Cory; Stahlhut, Julie K.; Steinke, Dirk; Whitfield, James; Wood, Monty; Zhou, Xin

    2012-01-01

    Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein – wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When >2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor – for which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region. PMID:22567162

  8. Native microbiome impedes vertical transmission of Wolbachia in Anopheles mosquitoes

    PubMed Central

    Hughes, Grant L.; Dodson, Brittany L.; Johnson, Rebecca M.; Murdock, Courtney C.; Tsujimoto, Hitoshi; Suzuki, Yasutsugu; Patt, Alyssa A.; Cui, Long; Nossa, Carlos W.; Barry, Rhiannon M.; Sakamoto, Joyce M.; Hornett, Emily A.; Rasgon, Jason L.

    2014-01-01

    Over evolutionary time, Wolbachia has been repeatedly transferred between host species contributing to the widespread distribution of the symbiont in arthropods. For novel infections to be maintained, Wolbachia must infect the female germ line after being acquired by horizontal transfer. Although mechanistic examples of horizontal transfer exist, there is a poor understanding of factors that lead to successful vertical maintenance of the acquired infection. Using Anopheles mosquitoes (which are naturally uninfected by Wolbachia) we demonstrate that the native mosquito microbiota is a major barrier to vertical transmission of a horizontally acquired Wolbachia infection. After injection into adult Anopheles gambiae, some strains of Wolbachia invade the germ line, but are poorly transmitted to the next generation. In Anopheles stephensi, Wolbachia infection elicited massive blood meal-induced mortality, preventing development of progeny. Manipulation of the mosquito microbiota by antibiotic treatment resulted in perfect maternal transmission at significantly elevated titers of the wAlbB Wolbachia strain in A. gambiae, and alleviated blood meal-induced mortality in A. stephensi enabling production of Wolbachia-infected offspring. Microbiome analysis using high-throughput sequencing identified that the bacterium Asaia was significantly reduced by antibiotic treatment in both mosquito species. Supplementation of an antibiotic-resistant mutant of Asaia to antibiotic-treated mosquitoes completely inhibited Wolbachia transmission and partly contributed to blood meal-induced mortality. These data suggest that the components of the native mosquito microbiota can impede Wolbachia transmission in Anopheles. Incompatibility between the microbiota and Wolbachia may in part explain why some hosts are uninfected by this endosymbiont in nature. PMID:25114252

  9. Wolbachia and DNA barcoding insects: patterns, potential, and problems.

    PubMed

    Smith, M Alex; Bertrand, Claudia; Crosby, Kate; Eveleigh, Eldon S; Fernandez-Triana, Jose; Fisher, Brian L; Gibbs, Jason; Hajibabaei, Mehrdad; Hallwachs, Winnie; Hind, Katharine; Hrcek, Jan; Huang, Da-Wei; Janda, Milan; Janzen, Daniel H; Li, Yanwei; Miller, Scott E; Packer, Laurence; Quicke, Donald; Ratnasingham, Sujeevan; Rodriguez, Josephine; Rougerie, Rodolphe; Shaw, Mark R; Sheffield, Cory; Stahlhut, Julie K; Steinke, Dirk; Whitfield, James; Wood, Monty; Zhou, Xin

    2012-01-01

    Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein--wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When >2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor--which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region.

  10. A host as an ecosystem: Wolbachia coping with environmental constraints.

    PubMed

    Sicard, Mathieu; Dittmer, Jessica; Grève, Pierre; Bouchon, Didier; Braquart-Varnier, Christine

    2014-12-01

    The Wolbachia are intracellular endosymbionts widely distributed among invertebrates. These primarily vertically transmitted α-proteobacteria have been intensively studied during the last decades because of their intriguing interactions with hosts, ranging from reproductive manipulations to mutualism. To optimize their vertical transmission from mother to offspring, the Wolbachia have developed fine-tuned strategies. However, the Wolbachia are not restricted to the female gonads and frequently exhibit wide intra-host distributions. This extensive colonization of somatic organs might be necessary for Wolbachia to develop their diverse extended phenotypes. From an endosymbiont's perspective, the within-host environment potentially presents different environmental constraints. Hence, the Wolbachia have to face different intracellular habitats, their host's immune system as well as other microorganisms co-occurring in the same host individual and sometimes even in the same cell. A means for the Wolbachia to protect themselves from these environmental constraints may be to live 'hidden' in vacuoles within host cells. In this review, we summarize the current knowledge regarding the extent of the Wolbachia pandemic and discuss the various environmental constraints these bacteria may have to face within their 'host ecosystem'. Finally, we identify new avenues for future research to better understand the complexity of Wolbachia's interactions with their intracellular environment.

  11. Wolbachia endosymbionts induce neutrophil extracellular trap formation in human onchocerciasis

    PubMed Central

    Tamarozzi, Francesca; Turner, Joseph D.; Pionnier, Nicolas; Midgley, Angela; Guimaraes, Ana F.; Johnston, Kelly L.; Edwards, Steven W.; Taylor, Mark J.

    2016-01-01

    The endosymbiotic bacteria, Wolbachia, induce neutrophilic responses to the human helminth pathogen Onchocerca volvulus. The formation of Neutrophil Extracellular Traps (NETs), has been implicated in anti-microbial defence, but has not been identified in human helminth infection. Here, we demonstrate NETs formation in human onchocerciasis. Extracellular NETs and neutrophils were visualised around O. volvulus in nodules excised from untreated patients but not in nodules from patients treated with the anti-Wolbachia drug, doxycycline. Whole Wolbachia or microspheres coated with a synthetic Wolbachia lipopeptide (WoLP) of the major nematode Wolbachia TLR2/6 ligand, peptidoglycan associated lipoprotein, induced NETosis in human neutrophils in vitro. TLR6 dependency of Wolbachia and WoLP NETosis was demonstrated using purified neutrophils from TLR6 deficient mice. Thus, we demonstrate for the first time that NETosis occurs during natural human helminth infection and demonstrate a mechanism of NETosis induction via Wolbachia endobacteria and direct ligation of Wolbachia lipoprotein by neutrophil TLR2/6. PMID:27752109

  12. Bacteria Endosymbiont, Wolbachia, Promotes Parasitism of Parasitoid Wasp Asobara japonica

    PubMed Central

    Matsumoto, Hitoshi; Hayakawa, Yoichi

    2015-01-01

    Wolbachia is the most widespread endosymbiotic bacterium that manipulates reproduction of its arthropod hosts to enhance its own spread throughout host populations. Infection with Wolbachia causes complete parthenogenetic reproduction in many Hymenoptera, producing only female offspring. The mechanism of such reproductive manipulation by Wolbachia has been extensively studied. However, the effects of Wolbachia symbiosis on behavioral traits of the hosts are scarcely investigated. The parasitoid wasp Asobara japonica is an ideal insect to investigate this because symbiotic and aposymbiotic strains are available: Wolbachia-infected Tokyo (TK) and noninfected Iriomote (IR) strains originally collected on the main island and southwest islands of Japan, respectively. We compared the oviposition behaviors of the two strains and found that TK strain females parasitized Drosophila melanogaster larvae more actively than the IR strain, especially during the first two days after eclosion. Removing Wolbachia from the TK strain wasps by treatment with tetracycline or rifampicin decreased their parasitism activity to the level of the IR strain. Morphological and behavioral analyses of both strain wasps showed that Wolbachia endosymbionts do not affect development of the host female reproductive tract and eggs, but do enhance host-searching ability of female wasps. These results suggest the possibility that Wolbachia endosymbionts may promote their diffusion and persistence in the host A. japonica population not only at least partly by parthenogenesis but also by enhancement of oviposition frequency of the host females. PMID:26492411

  13. Mutualistic Wolbachia infection in Aedes albopictus: accelerating cytoplasmic drive.

    PubMed Central

    Dobson, Stephen L; Marsland, Eric J; Rattanadechakul, Wanchai

    2002-01-01

    Maternally inherited rickettsial symbionts of the genus Wolbachia occur commonly in arthropods, often behaving as reproductive parasites by manipulating host reproduction to enhance the vertical transmission of infections. One manipulation is cytoplasmic incompatibility (CI), which causes a significant reduction in brood hatch and promotes the spread of the maternally inherited Wolbachia infection into the host population (i.e., cytoplasmic drive). Here, we have examined a Wolbachia superinfection in the mosquito Aedes albopictus and found the infection to be associated with both cytoplasmic incompatibility and increased host fecundity. Relative to uninfected females, infected females live longer, produce more eggs, and have higher hatching rates in compatible crosses. A model describing Wolbachia infection dynamics predicts that increased fecundity will accelerate cytoplasmic drive rates. To test this hypothesis, we used population cages to examine the rate at which Wolbachia invades an uninfected Ae. albopictus population. The observed cytoplasmic drive rates were consistent with model predictions for a CI-inducing Wolbachia infection that increases host fecundity. We discuss the relevance of these results to both the evolution of Wolbachia symbioses and proposed applied strategies for the use of Wolbachia infections to drive desired transgenes through natural populations (i.e., population replacement strategies). PMID:11901124

  14. Comparative Genomics of a Parthenogenesis-Inducing Wolbachia Symbiont

    PubMed Central

    Lindsey, Amelia R. I.; Werren, John H.; Richards, Stephen; Stouthamer, Richard

    2016-01-01

    Wolbachia is an intracellular symbiont of invertebrates responsible for inducing a wide variety of phenotypes in its host. These host-Wolbachia relationships span the continuum from reproductive parasitism to obligate mutualism, and provide a unique system to study genomic changes associated with the evolution of symbiosis. We present the genome sequence from a parthenogenesis-inducing Wolbachia strain (wTpre) infecting the minute parasitoid wasp Trichogramma pretiosum. The wTpre genome is the most complete parthenogenesis-inducing Wolbachia genome available to date. We used comparative genomics across 16 Wolbachia strains, representing five supergroups, to identify a core Wolbachia genome of 496 sets of orthologous genes. Only 14 of these sets are unique to Wolbachia when compared to other bacteria from the Rickettsiales. We show that the B supergroup of Wolbachia, of which wTpre is a member, contains a significantly higher number of ankyrin repeat-containing genes than other supergroups. In the wTpre genome, there is evidence for truncation of the protein coding sequences in 20% of ORFs, mostly as a result of frameshift mutations. The wTpre strain represents a conversion from cytoplasmic incompatibility to a parthenogenesis-inducing lifestyle, and is required for reproduction in the Trichogramma host it infects. We hypothesize that the large number of coding frame truncations has accompanied the change in reproductive mode of the wTpre strain. PMID:27194801

  15. Bacteria Endosymbiont, Wolbachia, Promotes Parasitism of Parasitoid Wasp Asobara japonica.

    PubMed

    Furihata, Shunsuke; Hirata, Makiko; Matsumoto, Hitoshi; Hayakawa, Yoichi

    2015-01-01

    Wolbachia is the most widespread endosymbiotic bacterium that manipulates reproduction of its arthropod hosts to enhance its own spread throughout host populations. Infection with Wolbachia causes complete parthenogenetic reproduction in many Hymenoptera, producing only female offspring. The mechanism of such reproductive manipulation by Wolbachia has been extensively studied. However, the effects of Wolbachia symbiosis on behavioral traits of the hosts are scarcely investigated. The parasitoid wasp Asobara japonica is an ideal insect to investigate this because symbiotic and aposymbiotic strains are available: Wolbachia-infected Tokyo (TK) and noninfected Iriomote (IR) strains originally collected on the main island and southwest islands of Japan, respectively. We compared the oviposition behaviors of the two strains and found that TK strain females parasitized Drosophila melanogaster larvae more actively than the IR strain, especially during the first two days after eclosion. Removing Wolbachia from the TK strain wasps by treatment with tetracycline or rifampicin decreased their parasitism activity to the level of the IR strain. Morphological and behavioral analyses of both strain wasps showed that Wolbachia endosymbionts do not affect development of the host female reproductive tract and eggs, but do enhance host-searching ability of female wasps. These results suggest the possibility that Wolbachia endosymbionts may promote their diffusion and persistence in the host A. japonica population not only at least partly by parthenogenesis but also by enhancement of oviposition frequency of the host females.

  16. Macronutrients mediate the functional relationship between Drosophila and Wolbachia.

    PubMed

    Ponton, Fleur; Wilson, Kenneth; Holmes, Andrew; Raubenheimer, David; Robinson, Katie L; Simpson, Stephen J

    2015-02-07

    Wolbachia are maternally inherited bacterial endosymbionts that naturally infect a diverse array of arthropods. They are primarily known for their manipulation of host reproductive biology, and recently, infections with Wolbachia have been proposed as a new strategy for controlling insect vectors and subsequent human-transmissible diseases. Yet, Wolbachia abundance has been shown to vary greatly between individuals and the magnitude of the effects of infection on host life-history traits and protection against infection is correlated to within-host Wolbachia abundance. It is therefore essential to better understand the factors that modulate Wolbachia abundance and effects on host fitness. Nutrition is known to be one of the most important mediators of host-symbiont interactions. Here, we used nutritional geometry to quantify the role of macronutrients on insect-Wolbachia relationships in Drosophila melanogaster. Our results show fundamental interactions between diet composition, host diet selection, Wolbachia abundance and effects on host lifespan and fecundity. The results and methods described here open a new avenue in the study of insect-Wolbachia relationships and are of general interest to numerous research disciplines, ranging from nutrition and life-history theory to public health. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  17. The impact of host diet on Wolbachia titer in Drosophila.

    PubMed

    Serbus, Laura R; White, Pamela M; Silva, Jessica Pintado; Rabe, Amanda; Teixeira, Luis; Albertson, Roger; Sullivan, William

    2015-03-01

    While a number of studies have identified host factors that influence endosymbiont titer, little is known concerning environmental influences on titer. Here we examined nutrient impact on maternally transmitted Wolbachia endosymbionts in Drosophila. We demonstrate that Drosophila reared on sucrose- and yeast-enriched diets exhibit increased and reduced Wolbachia titers in oogenesis, respectively. The yeast-induced Wolbachia depletion is mediated in large part by the somatic TOR and insulin signaling pathways. Disrupting TORC1 with the small molecule rapamycin dramatically increases oocyte Wolbachia titer, whereas hyper-activating somatic TORC1 suppresses oocyte titer. Furthermore, genetic ablation of insulin-producing cells located in the Drosophila brain abolished the yeast impact on oocyte titer. Exposure to yeast-enriched diets altered Wolbachia nucleoid morphology in oogenesis. Furthermore, dietary yeast increased somatic Wolbachia titer overall, though not in the central nervous system. These findings highlight the interactions between Wolbachia and germline cells as strongly nutrient-sensitive, and implicate conserved host signaling pathways by which nutrients influence Wolbachia titer.

  18. The Impact of Host Diet on Wolbachia Titer in Drosophila

    PubMed Central

    Serbus, Laura R.; White, Pamela M.; Silva, Jessica Pintado; Rabe, Amanda; Teixeira, Luis; Albertson, Roger; Sullivan, William

    2015-01-01

    While a number of studies have identified host factors that influence endosymbiont titer, little is known concerning environmental influences on titer. Here we examined nutrient impact on maternally transmitted Wolbachia endosymbionts in Drosophila. We demonstrate that Drosophila reared on sucrose- and yeast-enriched diets exhibit increased and reduced Wolbachia titers in oogenesis, respectively. The yeast-induced Wolbachia depletion is mediated in large part by the somatic TOR and insulin signaling pathways. Disrupting TORC1 with the small molecule rapamycin dramatically increases oocyte Wolbachia titer, whereas hyper-activating somatic TORC1 suppresses oocyte titer. Furthermore, genetic ablation of insulin-producing cells located in the Drosophila brain abolished the yeast impact on oocyte titer. Exposure to yeast-enriched diets altered Wolbachia nucleoid morphology in oogenesis. Furthermore, dietary yeast increased somatic Wolbachia titer overall, though not in the central nervous system. These findings highlight the interactions between Wolbachia and germline cells as strongly nutrient-sensitive, and implicate conserved host signaling pathways by which nutrients influence Wolbachia titer. PMID:25826386

  19. Wolbachia distribution in selected beetle taxa characterized by PCR screens and MLST data.

    PubMed

    Sontowski, Rebekka; Bernhard, Detlef; Bleidorn, Christoph; Schlegel, Martin; Gerth, Michael

    2015-10-01

    Wolbachia (Alphaproteobacteria) is an inherited endosymbiont of arthropods and filarial nematodes and was reported to be widespread across insect taxa. While Wolbachia's effects on host biology are not understood from most of these hosts, known Wolbachia-induced phenotypes cover a spectrum from obligate beneficial mutualism to reproductive manipulations and pathogenicity. Interestingly, data on Wolbachia within the most species-rich order of arthropods, the Coleoptera (beetles), are scarce. Therefore, we screened 128 species from seven beetle families (Buprestidae, Hydraenidae, Dytiscidae, Hydrophilidae, Gyrinidae, Haliplidae, and Noteridae) for the presence of Wolbachia. Our data show that, contrary to previous estimations, Wolbachia frequencies in beetles (31% overall) are comparable to the ones in other insects. In addition, we used Wolbachia MLST data and host phylogeny to explore the evolutionary history of Wolbachia strains from Hydraenidae, an aquatic lineage of beetles. Our data suggest that Wolbachia from Hydraenidae might be largely host genus specific and that Wolbachia strain phylogeny is not independent to that of its hosts. As this contrasts with most terrestrial Wolbachia-arthropod systems, one potential conclusion is that aquatic lifestyle of hosts may result in Wolbachia distribution patterns distinct from those of terrestrial hosts. Our data thus provide both insights into Wolbachia distribution among beetles in general and a first glimpse of Wolbachia distribution patterns among aquatic host lineages.

  20. Antiviral Protection and the Importance of Wolbachia Density and Tissue Tropism in Drosophila simulans

    PubMed Central

    Osborne, Sheree E.; Iturbe-Ormaetxe, Iñaki; Brownlie, Jeremy C.; O'Neill, Scott L.

    2012-01-01

    Wolbachia, a maternally transmitted endosymbiont of insects, is increasingly being seen as an effective biological control agent that can interfere with transmission of pathogens, including dengue virus. However, the mechanism of antiviral protection is not well understood. The density and distribution of Wolbachia in host tissues have been implicated as contributing factors by previous studies with both mosquitoes and flies. Drosophila flies infected with five diverse strains of Wolbachia were screened for the ability to mediate antiviral protection. The three protective Wolbachia strains were more closely related and occurred at a higher density within whole flies than the two nonprotective Wolbachia strains. In this study, to further investigate the relationship between whole-fly Wolbachia density and the ability to mediate antiviral protection, tetracycline was used to decrease the abundance of the high-density, protective Wolbachia strain wAu prior to viral challenge. Antiviral protection was lost when the density of the protective Wolbachia strain was decreased to an abundance similar to that of nonprotective Wolbachia strains. We determined the Wolbachia density and distribution in tissues of the same five fly-Wolbachia combinations as used previously. The Wolbachia density within the head, gut, and Malpighian tubules correlated with the ability to mediate antiviral protection. These findings may facilitate the development of Wolbachia biological control strategies and help to predict host-Wolbachia pairings that may interfere with virus-induced pathology. PMID:22843518

  1. Does a parthenogenesis-inducing Wolbachia induce vestigial cytoplasmic incompatibility?

    NASA Astrophysics Data System (ADS)

    Kraaijeveld, Ken; Reumer, Barbara M.; Mouton, Laurence; Kremer, Natacha; Vavre, Fabrice; van Alphen, Jacques J. M.

    2011-03-01

    Wolbachia is a maternally inherited bacterium that manipulates the reproduction of its host. Recent studies have shown that male-killing strains can induce cytoplasmic incompatibility (CI) when introgressed into a resistant host. Phylogenetic studies suggest that transitions between CI and other Wolbachia phenotypes have also occurred frequently, raising the possibility that latent CI may be widespread among Wolbachia. Here, we investigate whether a parthenogenesis-inducing Wolbachia strain can also induce CI. Parthenogenetic females of the parasitoid wasp Asobara japonica regularly produce a small number of males that may be either infected or not. Uninfected males were further obtained through removal of the Wolbachia using antibiotics and from a naturally uninfected strain. Uninfected females that had mated with infected males produced a slightly, but significantly more male-biased sex ratio than uninfected females that had mated with uninfected males. This effect was strongest in females that mated with males that had a relatively high Wolbachia titer. Quantitative PCR indicated that infected males did not show higher ratios of nuclear versus mitochondrial DNA content. Wolbachia therefore does not cause diploidization of cells in infected males. While these results are consistent with CI, other alternatives such as production of abnormal sperm by infected males cannot be completely ruled out. Overall, the effect was very small (9%), suggesting that if CI is involved it may have degenerated through the accumulation of mutations.

  2. Male-killing Wolbachia in two species of insect

    PubMed Central

    Hurst, G. D. D.; Jiggins, F. M.; Schulenburg, J. H. G. von der; Bertrand, D.; West, S. A.; Goriacheva, I. I.; Zakharov, I. A.; Werren, J. H.; Stouthamer, R.; Majerus, M. E. N.

    1999-01-01

    The inherited bacterium Wolbachia spreads through the manipulation of host reproduction, and has been suggested to be an important factor in arthropod evolution, from host speciation to the evolution of sex-determination systems. Past work has shown that members of this group may produce cytoplasmic incompatibility, feminize genetically male hosts, and induce host parthenogenesis. Here, we report an expansion of the range of reproductive manipulations produced by members of this clade, recording Wolbachia strains that kill male hosts during embryogenesis in two host species, the ladybird Adalia bipunctata, and the butterfly Acraea encedon. Both male-killing bacteria belong to the B group of Wolbachia. However, phylogenetic analyses were unable to resolve whether the bacteria in the two species are monophyletic, or represent independent origins of male-killing among the B-group Wolbachia. We also found significant divergence within the wsp gene of Wolbachia strains found in different A. bipunctata individuals, suggesting this host species contains two Wolbachia strains, diverged in wsp sequence but monophyletic. Our observations reinforce the notion that Wolbachia may be an important agent driving arthropod evolution, and corroborates previous suggestions that male-killing behaviour is easily evolved by invertebrate symbionts.

  3. Modelling the spread of Wolbachia in spatially heterogeneous environments.

    PubMed

    Hancock, Penelope A; Godfray, H Charles J

    2012-11-07

    The endosymbiont Wolbachia infects a large number of insect species and is capable of rapid spread when introduced into a novel host population. The bacteria spread by manipulating their hosts' reproduction, and their dynamics are influenced by the demographic structure of the host population and patterns of contact between individuals. Reaction-diffusion models of the spatial spread of Wolbachia provide a simple analytical description of their spatial dynamics but do not account for significant details of host population dynamics. We develop a metapopulation model describing the spatial dynamics of Wolbachia in an age-structured host insect population regulated by juvenile density-dependent competition. The model produces similar dynamics to the reaction-diffusion model in the limiting case where the host's habitat quality is spatially homogeneous and Wolbachia has a small effect on host fitness. When habitat quality varies spatially, Wolbachia spread is usually much slower, and the conditions necessary for local invasion are strongly affected by immigration of insects from surrounding regions. Spread is most difficult when variation in habitat quality is spatially correlated. The results show that spatial variation in the density-dependent competition experienced by juvenile host insects can strongly affect the spread of Wolbachia infections, which is important to the use of Wolbachia to control insect vectors of human disease and other pests.

  4. Rapid Sequential Spread of Two Wolbachia Variants in Drosophila simulans

    PubMed Central

    Kriesner, Peter; Hoffmann, Ary A.; Lee, Siu F.; Turelli, Michael; Weeks, Andrew R.

    2013-01-01

    The maternally inherited intracellular bacteria Wolbachia can manipulate host reproduction in various ways that foster frequency increases within and among host populations. Manipulations involving cytoplasmic incompatibility (CI), where matings between infected males and uninfected females produce non-viable embryos, are common in arthropods and produce a reproductive advantage for infected females. CI was associated with the spread of Wolbachia variant wRi in Californian populations of Drosophila simulans, which was interpreted as a bistable wave, in which local infection frequencies tend to increase only once the infection becomes sufficiently common to offset imperfect maternal transmission and infection costs. However, maternally inherited Wolbachia are expected to evolve towards mutualism, and they are known to increase host fitness by protecting against infectious microbes or increasing fecundity. We describe the sequential spread over approximately 20 years in natural populations of D. simulans on the east coast of Australia of two Wolbachia variants (wAu and wRi), only one of which causes significant CI, with wRi displacing wAu since 2004. Wolbachia and mtDNA frequency data and analyses suggest that these dynamics, as well as the earlier spread in California, are best understood as Fisherian waves of favourable variants, in which local spread tends to occur from arbitrarily low frequencies. We discuss implications for Wolbachia-host dynamics and coevolution and for applications of Wolbachia to disease control. PMID:24068927

  5. Male-killing Wolbachia in a flour beetle.

    PubMed Central

    Fialho, R F; Stevens, L

    2000-01-01

    The bacteria in the genus Wolbachia are cytoplasmically inherited symbionts of arthropods. Infection often causes profound changes in host reproduction, enhancing bacterial transmission and spread in a population. The reproductive alterations known to result from Wolbachia infection include cytoplasmic incompatibility (CI), parthenogenesis, feminization of genetic males, fecundity enhancement, male killing and, perhaps, lethality Here, we report male killing in a third insect, the black flour beetle Tribolium madens, based on highly female-biased sex ratios of progeny from females infected with Wolbachia. The bias is cytoplasmic in nature as shown by repeated backcrossing of infected females with males of a naturally uninfected strain. Infection also lowers the egg hatch rates significantly to approximately half of those observed for uninfected females. Treatment of the host with antibiotics eliminated infection, reverted the sex ratio to unbiased levels and increased the percentage hatch. Typically Wolbachia infection is transmitted from mother to progeny, regardless of the sex of the progeny; however, infected T. madens males are never found. Virgin females are sterile, suggesting that the sex-ratio distortion in T. madens results from embryonic male killing rather than parthenogenesis. Based on DNA sequence data, the male-killing strain of Wolbachia in T. madens was indistinguishable from the CI-inducing Wolbachia in Tribolium confusum, a closely related beetle. Our findings suggest that host symbiont interaction effects may play an important role in the induction of Wolbachia reproductive phenotypes. PMID:10983833

  6. Inactivation of Wolbachia Reveals Its Biological Roles in Whitefly Host

    PubMed Central

    Xue, Xia; Li, Shao-Jian; Ahmed, Muhammad Z.; De Barro, Paul J.; Ren, Shun-Xiang; Qiu, Bao-Li

    2012-01-01

    Background The whitefly Bemisia tabaci is cryptic species complex composed of numerous species. Individual species from the complex harbor a diversity of bacterial endosymbionts including Wolbachia. However, while Wolbachia is known to have a number of different roles, its role in B. tabaci is unclear. Here, the antibiotic rifampicin is used to selectively eliminate Wolbachia from B. tabaci so as to enable its roles in whitefly development and reproduction to be explored. The indirect effects of Wolbachia elimination on the biology of Encarsia bimaculata, a dominant parasitoid of B. tabaci in South China, were also investigated. Methodology/Principal Finding qRT-PCR and FISH were used to show that after 48 h exposure to 1.0 mg/ml rifampicin, Wolbachia was completely inactivated from B. tabaci Mediterranean (MED) without any significant impact on either the primary symbiont, Portiera aleyrodidarum or any of the other secondary endosymbionts present. For B. tabaci MED, Wolbachia was shown to be associated with decreased juvenile development time, increased likelihood that nymphs completed development, increased adult life span and increased percentage of female progeny. Inactivation was associated with a significant decrease in the body size of the 4th instar which leads us to speculate as to whether Wolbachia may have a nutrient supplementation role. The reduction in nymph body size has consequences for its parasitoid, E. bimaculata. The elimination of Wolbachia lead to a marked increase in the proportion of parasitoid eggs that completed their development, but the reduced size of the whitefly host was also associated with a significant reduction in the size of the emerging parasitoid adult and this was in turn associated with a marked reduction in adult parasitoid longevity. Conclusions/Significance Wolbachia increases the fitness of the whitefly host and provides some protection against parasitization. These observations add to our understanding of the roles

  7. Inactivation of Wolbachia reveals its biological roles in whitefly host.

    PubMed

    Xue, Xia; Li, Shao-Jian; Ahmed, Muhammad Z; De Barro, Paul J; Ren, Shun-Xiang; Qiu, Bao-Li

    2012-01-01

    The whitefly Bemisia tabaci is cryptic species complex composed of numerous species. Individual species from the complex harbor a diversity of bacterial endosymbionts including Wolbachia. However, while Wolbachia is known to have a number of different roles, its role in B. tabaci is unclear. Here, the antibiotic rifampicin is used to selectively eliminate Wolbachia from B. tabaci so as to enable its roles in whitefly development and reproduction to be explored. The indirect effects of Wolbachia elimination on the biology of Encarsia bimaculata, a dominant parasitoid of B. tabaci in South China, were also investigated. qRT-PCR and FISH were used to show that after 48 h exposure to 1.0 mg/ml rifampicin, Wolbachia was completely inactivated from B. tabaci Mediterranean (MED) without any significant impact on either the primary symbiont, Portiera aleyrodidarum or any of the other secondary endosymbionts present. For B. tabaci MED, Wolbachia was shown to be associated with decreased juvenile development time, increased likelihood that nymphs completed development, increased adult life span and increased percentage of female progeny. Inactivation was associated with a significant decrease in the body size of the 4(th) instar which leads us to speculate as to whether Wolbachia may have a nutrient supplementation role. The reduction in nymph body size has consequences for its parasitoid, E. bimaculata. The elimination of Wolbachia lead to a marked increase in the proportion of parasitoid eggs that completed their development, but the reduced size of the whitefly host was also associated with a significant reduction in the size of the emerging parasitoid adult and this was in turn associated with a marked reduction in adult parasitoid longevity. Wolbachia increases the fitness of the whitefly host and provides some protection against parasitization. These observations add to our understanding of the roles played by bacterial endosymbionts.

  8. The emerging role of Wolbachia species in heartworm disease.

    PubMed

    Frank, Kristen; Heald, R Dennis

    2010-04-01

    Heartworm disease was first recognized in dogs more than 100 years ago and is still prevalent among dogs and found in cats worldwide. The complications of heartworm disease can be devastating, and treatment carries risks. Wolbachia spp are gram-negative bacteria that infect filarial nematodes, including Dirofilaria immitis, and elicit an inflammatory response in cats and dogs. Antimicrobial therapy directed against these bacteria has resulted in decreased microfilarial loads, inhibition of the development of larval worms, female worm infertility, and reduced numbers of Wolbachia organisms. Antimicrobial therapy against Wolbachia spp may be useful in treating heartworm disease in cats and dogs, but further research is needed.

  9. Monitoring long-term evolutionary changes following Wolbachia introduction into a novel host: the Wolbachia popcorn infection in Drosophila simulans.

    PubMed

    Carrington, Lauren B; Hoffmann, Ary A; Weeks, Andrew R

    2010-07-07

    Wolbachia may act as a biological control agent for pest management; in particular, the Wolbachia variant wMelPop (popcorn) shortens host longevity and may be useful for dengue suppression. However, long-term changes in the host and Wolbachia genomes can alter Wolbachia spread and/or host effects that suppress disease. Here, we investigate the phenotypic effects of wMelPop in a non-native host, Drosophila simulans, following artificial transinfection approximately 200 generations ago. Long-term rearing and maintenance of the bacteria were at 19 degrees C in the original I-102 genetic background that was transinfected with the popcorn strain. The bacteria were then introgressed into three massbred backgrounds, and tetracycline was used to create uninfected sublines. The effect of wMelPop on longevity in this species appears to have changed; longevity was no longer reduced at 25 degrees C in some nuclear backgrounds, reflecting different geographical origin, selection or drift, although the reduction was still evident for flies held at 30 degrees C. Wolbachia influenced productivity and viability, and development time in some host backgrounds. These findings suggest that long-term attenuation of Wolbachia effects may compromise the effectiveness of this bacterium in pest control. They also emphasize the importance of host nuclear background on Wolbachia phenotypic effects.

  10. Monitoring long-term evolutionary changes following Wolbachia introduction into a novel host: the Wolbachia popcorn infection in Drosophila simulans

    PubMed Central

    Carrington, Lauren B.; Hoffmann, Ary A.; Weeks, Andrew R.

    2010-01-01

    Wolbachia may act as a biological control agent for pest management; in particular, the Wolbachia variant wMelPop (popcorn) shortens host longevity and may be useful for dengue suppression. However, long-term changes in the host and Wolbachia genomes can alter Wolbachia spread and/or host effects that suppress disease. Here, we investigate the phenotypic effects of wMelPop in a non-native host, Drosophila simulans, following artificial transinfection approximately 200 generations ago. Long-term rearing and maintenance of the bacteria were at 19°C in the original I-102 genetic background that was transinfected with the popcorn strain. The bacteria were then introgressed into three massbred backgrounds, and tetracycline was used to create uninfected sublines. The effect of wMelPop on longevity in this species appears to have changed; longevity was no longer reduced at 25°C in some nuclear backgrounds, reflecting different geographical origin, selection or drift, although the reduction was still evident for flies held at 30°C. Wolbachia influenced productivity and viability, and development time in some host backgrounds. These findings suggest that long-term attenuation of Wolbachia effects may compromise the effectiveness of this bacterium in pest control. They also emphasize the importance of host nuclear background on Wolbachia phenotypic effects. PMID:20219740

  11. [Genotypic Diversity of Wolbachia pipientis in Native and Invasive Harmonia axyridis Pall., 1773 (Coleoptera, Coccinellidae) Populations].

    PubMed

    Goryacheva, I I; Blekhman, A V; Andrianov, B V; Gorelova, T V; Zakharov, I A

    2015-08-01

    The distribution and variability of reproductive symbiotic Wolbachia pipientis bacteria were studied in seven native and six invasive H. axyridis populations. Wolbachia-infected individuals were found in two invasive and two native populations. We demonstrated for the first time an infection of invasive H. axyridis populations with Wolbachia. Two new molecular forms of Wolbachia were detected by a system of multilocus typing. The supergroup A Wolbachia was found for the first time in H. axyridis. The detected genotypic diversity of Wolbachia indicates repeated and independent infection events in the evolutionary past of H. axyridis.

  12. Asymmetrical reinforcement and Wolbachia infection in Drosophila.

    PubMed

    Jaenike, John; Dyer, Kelly A; Cornish, Chad; Minhas, Miranda S

    2006-10-01

    Reinforcement refers to the evolution of increased mating discrimination against heterospecific individuals in zones of geographic overlap and can be considered a final stage in the speciation process. One the factors that may affect reinforcement is the degree to which hybrid matings result in the permanent loss of genes from a species' gene pool. Matings between females of Drosophila subquinaria and males of D. recens result in high levels of offspring mortality, due to interspecific cytoplasmic incompatibility caused by Wolbachia infection of D. recens. Such hybrid inviability is not manifested in matings between D. recens females and D. subquinaria males. Here we ask whether the asymmetrical hybrid inviability is associated with a corresponding asymmetry in the level of reinforcement. The geographic ranges of D. recens and D. subquinaria were found to overlap across a broad belt of boreal forest in central Canada. Females of D. subquinaria from the zone of sympatry exhibit much stronger levels of discrimination against males of D. recens than do females from allopatric populations. In contrast, such reproductive character displacement is not evident in D. recens, consistent with the expected effects of unidirectional cytoplasmic incompatibility. Furthermore, there is substantial behavioral isolation within D. subquinaria, because females from populations sympatric with D. recens discriminate against allopatric conspecific males, whereas females from populations allopatric with D. recens show no discrimination against any conspecific males. Patterns of general genetic differentiation among populations are not consistent with patterns of behavioral discrimination, which suggests that the behavioral isolation within D. subquinaria results from selection against mating with Wolbachia-infected D. recens. Interspecific cytoplasmic incompatibility may contribute not only to post-mating isolation, an effect already widely recognized, but also to reinforcement

  13. 150 Passenger Commercial Aircraft

    NASA Technical Reports Server (NTRS)

    Bucovsky, Adrian; Romli, Fairuz I.; Rupp, Jessica

    2002-01-01

    It has been projected that the need for a short-range mid-sized, aircraft is increasing. The future strategy to decrease long-haul flights will increase the demand for short-haul flights. Since passengers prefer to meet their destinations quickly, airlines will increase the frequency of flights, which will reduce the passenger load on the aircraft. If a point-to-point flight is not possible, passengers will prefer only a one-stop short connecting flight to their final destination. A 150-passenger aircraft is an ideal vehicle for these situations. It is mid-sized aircraft and has a range of 3000 nautical miles. This type of aircraft would market U.S. domestic flights or inter-European flight routes. The objective of the design of the 150-passenger aircraft is to minimize fuel consumption. The configuration of the aircraft must be optimized. This aircraft must meet CO2 and NOx emissions standards with minimal acquisition price and operating costs. This report contains all the work that has been performed for the completion of the design of a 150 passenger commercial aircraft. The methodology used is the Technology Identification, Evaluation, and Selection (TIES) developed at Georgia Tech Aerospace Systems Design laboratory (ASDL). This is an eight-step conceptual design process to evaluate the probability of meeting the design constraints. This methodology also allows for the evaluation of new technologies to be implemented into the design. The TIES process begins with defining the problem with a need established and a market targeted. With the customer requirements set and the target values established, a baseline concept is created. Next, the design space is explored to determine the feasibility and viability of the baseline aircraft configuration. If the design is neither feasible nor viable, new technologies can be implemented to open up the feasible design space and allow for a plausible solution. After the new technologies are identified, they must be evaluated

  14. Passenger-accompanied luggage.

    PubMed

    Williams, J C

    1977-09-01

    This paper describes an attempt to formalize luggage dimension information obtained in the course of a study of passenger attitudes to various luggage handling systems. Frequency distributions of the dimensions have been plotted, and correlations and partial correlations have been calculated which indicate the degree of dependence of one variable upon another. Regression equations have also been calculated, enabling accurate predictions to be made about the usefulness, or otherwise, of luggage storage areas. Passenger behaviour observed in the process of using a luggage handling system is discussed, and an equation relating luggage dimensions to the dimensions of the storage area and the manipulation area has been derived to aid the design of complete vehicular luggage storage systems where space is at a premium.

  15. Passengers of Impaired Drivers

    PubMed Central

    Romano, Eduardo; Kelley-Baker, Tara; Lacey, John

    2012-01-01

    Introduction The aims of this study are (a) to estimate the prevalence of passengers riding with alcohol-impaired drivers; (b) to investigate the role of demographic factors (age, gender, race/ethnicity, educational status) and relevant driving conditions (time of the day, trip origin, vehicle ownership) on shaping the likelihood of alcohol-impaired driving; (c) to identify and estimate the prevalence of passengers as alternative drivers (PADs); and (d) to examine the role that vehicle ownership plays in shaping the occurrence of PADs. Method Data came from a unique convenience sample of passengers obtained from the 2007 National Roadside Survey, a random sample of drivers from the 48 contiguous states. Results The prevalence of PADs in the targeted population (mostly weekend night vehicles) was higher with drivers at .00

  16. Child passenger safety.

    PubMed

    Durbin, Dennis R

    2011-04-01

    Despite significant reductions in the number of children killed in motor vehicle crashes over the past decade, crashes continue to be the leading cause of death for children 4 years and older. Therefore, the American Academy of Pediatrics continues to recommend inclusion of child passenger safety anticipatory guidance at every health-supervision visit. This technical report provides a summary of the evidence in support of 5 recommendations for best practices to optimize safety in passenger vehicles for children from birth through adolescence that all pediatricians should know and promote in their routine practice. These recommendations are presented in the revised policy statement on child passenger safety in the form of an algorithm that is intended to facilitate their implementation by pediatricians with their patients and families. The algorithm is designed to cover the majority of situations that pediatricians will encounter in practice. In addition, a summary of evidence on a number of additional issues that affect the safety of children in motor vehicles, including the proper use and installation of child restraints, exposure to air bags, travel in pickup trucks, children left in or around vehicles, and the importance of restraint laws, is provided. Finally, this technical report provides pediatricians with a number of resources for additional information to use when providing anticipatory guidance to families.

  17. Child passenger safety.

    PubMed

    Durbin, Dennis R

    2011-04-01

    Child passenger safety has dramatically evolved over the past decade; however, motor vehicle crashes continue to be the leading cause of death of children 4 years and older. This policy statement provides 4 evidence-based recommendations for best practices in the choice of a child restraint system to optimize safety in passenger vehicles for children from birth through adolescence: (1) rear-facing car safety seats for most infants up to 2 years of age; (2) forward-facing car safety seats for most children through 4 years of age; (3) belt-positioning booster seats for most children through 8 years of age; and (4) lap-and-shoulder seat belts for all who have outgrown booster seats. In addition, a fifth evidence-based recommendation is for all children younger than 13 years to ride in the rear seats of vehicles. It is important to note that every transition is associated with some decrease in protection; therefore, parents should be encouraged to delay these transitions for as long as possible. These recommendations are presented in the form of an algorithm that is intended to facilitate implementation of the recommendations by pediatricians to their patients and families and should cover most situations that pediatricians will encounter in practice. The American Academy of Pediatrics urges all pediatricians to know and promote these recommendations as part of child passenger safety anticipatory guidance at every health-supervision visit.

  18. Temperature alters Plasmodium blocking by Wolbachia

    NASA Astrophysics Data System (ADS)

    Murdock, Courtney C.; Blanford, Simon; Hughes, Grant L.; Rasgon, Jason L.; Thomas, Matthew B.

    2014-02-01

    Very recently, the Asian malaria vector (Anopheles stephensi) was stably transinfected with the wAlbB strain of Wolbachia, inducing refractoriness to the human malaria parasite Plasmodium falciparum. However, conditions in the field can differ substantially from those in the laboratory. We use the rodent malaria P. yoelii, and somatically transinfected An. stephensi as a model system to investigate whether the transmission blocking potential of wAlbB is likely to be robust across different thermal environments. wAlbB reduced malaria parasite prevalence and oocyst intensity at 28°C. At 24°C there was no effect on prevalence but a marked increase in oocyst intensity. At 20°C, wAlbB had no effect on prevalence or intensity. Additionally, we identified a novel effect of wAlbB that resulted in reduced sporozoite development across temperatures, counterbalancing the oocyst enhancement at 24°C. Our results demonstrate complex effects of temperature on the Wolbachia-malaria interaction, and suggest the impacts of transinfection might vary across diverse environments.

  19. Exploiting Intimate Relationships: Controlling Mosquito-Transmitted Disease with Wolbachia.

    PubMed

    Caragata, Eric P; Dutra, Heverton L C; Moreira, Luciano A

    2016-03-01

    Mosquito-transmitted diseases impose a growing burden on human health, and current control strategies have proven insufficient to stem the tide. The bacterium Wolbachia is a novel and promising form of control for mosquito-transmitted disease. It manipulates host biology, restricts infection with dengue and other pathogens, and alters host reproduction to promote rapid spread in the field. In this review, we examine how the intimate and diverse relationships formed between Wolbachia and their mosquito hosts can be exploited for disease control purposes. We consider these relationships in the context of recent developments, including successful field trials with Wolbachia-infected mosquitoes to combat dengue, and new Wolbachia infections in key malaria vectors, which have enhanced the disease control prospects of this unique bacterium.

  20. The Tripartite Associations between Bacteriophage, Wolbachia, and Arthropods

    PubMed Central

    Bordenstein, Seth R; Marshall, Michelle L; Fry, Adam J; Kim, Ulandt; Wernegreen, Jennifer J

    2006-01-01

    By manipulating arthropod reproduction worldwide, the heritable endosymbiont Wolbachia has spread to pandemic levels. Little is known about the microbial basis of cytoplasmic incompatibility (CI) except that bacterial densities and percentages of infected sperm cysts associate with incompatibility strength. The recent discovery of a temperate bacteriophage (WO-B) of Wolbachia containing ankyrin-encoding genes and virulence factors has led to intensifying debate that bacteriophage WO-B induces CI. However, current hypotheses have not considered the separate roles that lytic and lysogenic phage might have on bacterial fitness and phenotype. Here we describe a set of quantitative approaches to characterize phage densities and its associations with bacterial densities and CI. We enumerated genome copy number of phage WO-B and Wolbachia and CI penetrance in supergroup A- and B-infected males of the parasitoid wasp Nasonia vitripennis. We report several findings: (1) variability in CI strength for A-infected males is positively associated with bacterial densities, as expected under the bacterial density model of CI, (2) phage and bacterial densities have a significant inverse association, as expected for an active lytic infection, and (3) CI strength and phage densities are inversely related in A-infected males; similarly, males expressing incomplete CI have significantly higher phage densities than males expressing complete CI. Ultrastructural analyses indicate that approximately 12% of the A Wolbachia have phage particles, and aggregations of these particles can putatively occur outside the Wolbachia cell. Physical interactions were observed between approximately 16% of the Wolbachia cells and spermatid tails. The results support a low to moderate frequency of lytic development in Wolbachia and an overall negative density relationship between bacteriophage and Wolbachia. The findings motivate a novel phage density model of CI in which lytic phage repress Wolbachia

  1. Association of Wolbachia with heartworm disease in cats and dogs.

    PubMed

    Dingman, Patricia; Levy, Julie K; Kramer, Laura H; Johnson, Calvin M; Lappin, Michael R; Greiner, Ellis C; Courtney, Charles H; Tucker, Sylvia J; Morchon, Rodrigo

    2010-05-28

    Although the presence of adult Dirofilaria immitis in the pulmonary arteries and its associated arteritis and thromboembolic disease can explain some of the manifestations of canine and feline heartworm disease, the cause of other findings remains unclear. Cats with D. immitis antibodies but lacking adult parasites in the pulmonary arteries frequently develop histological lesions of the airways, resulting in a condition termed Heartworm-Associated Respiratory Disease. All D. immitis parasites harbor Wolbachia pipientis bacteria and D. immitis-infected animals can have circulating Wolbachia antibodies and pro-inflammatory Wolbachia antigens (WSP) deposited in tissues. Little is known about the role that Wolbachia plays in lung disease of animals naturally infected with D. immitis. The purpose of this study was to determine the contribution of Wolbachia to the pathogenesis of natural heartworm disease in cats and dogs. We hypothesized that animals having sufficient Wolbachia burden to be detected in lung tissue by immunohistochemistry and/or polymerase chain reaction (PCR) would have more severe pulmonary disease than those with bacteria below the limits of detection. We further hypothesized that animals that were immunoreactive to pro-inflammatory WSP would have more severe pulmonary lesions than those that were seronegative for WSP antibodies. Blood and lung tissue samples were collected from cats and dogs representing three different D. immitis infection statuses: heartworm-free, heartworm-exposed, heartworm-infected. There was a positive but weak correlation between the magnitude of D. immitis antibody titers and WSP titers in cats (r=0.57, p<0.001) and in dogs (r=0.39, p<0.001). Pulmonary lesions were more common in HW-infected animals than in HW-free animals. Pulmonary arteriolar occlusion was more common in HW-infected cats (57%; p=0.003) than in HW-infected dogs (17%). Although pulmonary lesions were most common in HW-infected animals, there was no clear

  2. Wolbachia Modulates Lipid Metabolism in Aedes albopictus Mosquito Cells

    PubMed Central

    Molloy, Jennifer C.; Sommer, Ulf; Viant, Mark R.

    2016-01-01

    ABSTRACT Certain strains of the intracellular endosymbiont Wolbachia can strongly inhibit or block the transmission of viruses such as dengue virus (DENV) by Aedes mosquitoes, and the mechanisms responsible are still not well understood. Direct infusion and liquid chromatography-Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry-based lipidomics analyses were conducted using Aedes albopictus Aa23 cells that were infected with the wMel and wMelPop strains of Wolbachia in comparison to uninfected Aa23-T cells. Substantial shifts in the cellular lipid profile were apparent in the presence of Wolbachia. Most significantly, almost all sphingolipid classes were depleted, and some reductions in diacylglycerols and phosphatidylcholines were also observed. These lipid classes have previously been shown to be selectively enriched in DENV-infected mosquito cells, suggesting that Wolbachia may produce a cellular lipid environment that is antagonistic to viral replication. The data improve our understanding of the intracellular interactions between Wolbachia and mosquitoes. IMPORTANCE Mosquitoes transmit a variety of important viruses to humans, such as dengue virus and Zika virus. Certain strains of the intracellular bacterial genus called Wolbachia found in or introduced into mosquitoes can block the transmission of viruses, including dengue virus, but the mechanisms responsible are not well understood. We found substantial shifts in the cellular lipid profiles in the presence of these bacteria. Some lipid classes previously shown to be enriched in dengue virus-infected mosquito cells were depleted in the presence of Wolbachia, suggesting that Wolbachia may produce a cellular lipid environment that inhibits mosquito-borne viruses. PMID:26994075

  3. PCR analysis for Wolbachia in human and canine Demodex mites.

    PubMed

    Borgo, Sibylle N; Sattler, Elke C; Hogardt, Michael; Adler, Kristin; Plewig, Gerd

    2009-10-01

    In many skin diseases such as Demodex folliculitis, rosacea- or steroid-induced rosacea Demodex mites are present in abundance and are at least partially held responsible for causing these disorders. Although it is known that these diseases respond well to tetracyclines, it is unclear if this is due to the antiinflammatory effects of the antibiotics or to an antibacterial effect on so far unknown bacteria within the Demodex mites. As in filariasis, where the response to doxycycline can be explained by the presence of Wolbachia within the filarial nematodes, this study was performed to see whether Wolbachia also use Demodex mites as their hosts. Human and canine Demodex mite samples were taken by skin scrapings and tested by PCR for the presence of Wolbachia DNA. Wolbachia pipientis DNA was used as positive control. In none of the DNA extracts, Wolbachia were detected showing no evidence for the presence of these bacteria in Demodex mites. The response of Demodex aggravated or Demodex caused diseases to tetracyclines seems not to be due to the presence of Wolbachia in Demodex mites in contrast to the results seen in filariasis.

  4. Wolbachia increases the susceptibility of a parasitoid wasp to hyperparasitism.

    PubMed

    van Nouhuys, Saskya; Kohonen, Minna; Duplouy, Anne

    2016-10-01

    The success of maternally transmitted endosymbiotic bacteria, such as Wolbachia, is directly linked to their host reproduction but in direct conflict with other parasites that kill the host before it reaches reproductive maturity. Therefore, symbionts that have evolved strategies to increase their host's ability to evade lethal parasites may have high penetrance, while detrimental symbionts would be selected against, leading to lower penetrance or extinction from the host population. In a natural population of the parasitoid wasp Hyposoter horticola in the Åland Islands (Finland), the Wolbachia strain wHho persists at an intermediate prevalence (∼50%). Additionally, there is a negative correlation between the prevalence of Wolbachia and a hyperparasitoid wasp, Mesochorus cf. stigmaticus, in the landscape. Using a manipulative field experiment, we addressed the persistence of Wolbachia at this intermediate level, and tested whether the observed negative correlation could be due to Wolbachia inducing either susceptibility or resistance to parasitism. We show that infection with Wolbachia does not influence the ability of the wasp to parasitize its butterfly host, Melitaea cinxia, but that hyperparasitism of the wasp increases in the presence of wHho. Consequently, the symbiont is detrimental, and in order to persist in the host population, must also have a positive effect on fitness that outweighs the costly burden of susceptibility to widespread parasitism. © 2016. Published by The Company of Biologists Ltd.

  5. Wolbachia infection density in populations of the Asian citrus psyllid (Hemiptera: Liviidae).

    PubMed

    Hoffmann, M; Coy, M R; Kingdom Gibbard, H N; Pelz-Stelinski, K S

    2014-10-01

    The symbiotic relationships between bacteria of the genus Wolbachia (order Rickettsiales) and their arthropod hosts are diverse and can range from mutualism to parasitism. Whereas effects of Wolbachia on host biology are well investigated, little is known about diversity and abundance of Wolbachia in their natural hosts. The phloem-feeding Asian citrus psyllid, Diaphorina citri (Kuwayama) (Hemiptera: Liviidae), is naturally infected with Wolbachia (wDi). In the current study, we calculated the within-host density of Wolbachia in Florida D. citri populations using quantitative polymerase chain reaction for detection of the Wolbachia outer surface protein gene, wsp. Gene quantities were normalized to the D. citri wingless gene (Wg) to estimate Wolbachia abundance in individual D. citri. Using this method, significant geographic differences in Wolbachia densities were detected among Florida D. citri populations, with higher infection levels occurring in male versus female hosts.

  6. Palaeosymbiosis revealed by genomic fossils of Wolbachia in a strongyloidean nematode.

    PubMed

    Koutsovoulos, Georgios; Makepeace, Benjamin; Tanya, Vincent N; Blaxter, Mark

    2014-06-01

    Wolbachia are common endosymbionts of terrestrial arthropods, and are also found in nematodes: the animal-parasitic filaria, and the plant-parasite Radopholus similis. Lateral transfer of Wolbachia DNA to the host genome is common. We generated a draft genome sequence for the strongyloidean nematode parasite Dictyocaulus viviparus, the cattle lungworm. In the assembly, we identified nearly 1 Mb of sequence with similarity to Wolbachia. The fragments were unlikely to derive from a live Wolbachia infection: most were short, and the genes were disabled through inactivating mutations. Many fragments were co-assembled with definitively nematode-derived sequence. We found limited evidence of expression of the Wolbachia-derived genes. The D. viviparus Wolbachia genes were most similar to filarial strains and strains from the host-promiscuous clade F. We conclude that D. viviparus was infected by Wolbachia in the past, and that clade F-like symbionts may have been the source of filarial Wolbachia infections.

  7. Evidence of natural Wolbachia infections in field populations of Anopheles gambiae.

    PubMed

    Baldini, Francesco; Segata, Nicola; Pompon, Julien; Marcenac, Perrine; Shaw, W Robert; Dabiré, Roch K; Diabaté, Abdoulaye; Levashina, Elena A; Catteruccia, Flaminia

    2014-06-06

    Wolbachia are maternally transmitted intracellular bacteria that invade insect populations by manipulating their reproduction and immunity and thus limiting the spread of numerous human pathogens. Experimental Wolbachia infections can reduce Plasmodium numbers in Anopheles mosquitoes in the laboratory, however, natural Wolbachia infections in field anophelines have never been reported. Here we show evidence of Wolbachia infections in Anopheles gambiae in Burkina Faso, West Africa. Sequencing of the 16S rRNA gene identified Wolbachia sequences in both female and male germlines across two seasons, and determined that these sequences are vertically transmitted from mother to offspring. Whole-genome sequencing of positive samples suggests that the genetic material identified in An. gambiae belongs to a novel Wolbachia strain, related to but distinct from strains infecting other arthropods. The evidence of Wolbachia infections in natural Anopheles populations promotes further investigations on the possible use of natural Wolbachia-Anopheles associations to limit malaria transmission.

  8. Wolbachia Has Two Different Localization Patterns in Whitefly Bemisia tabaci AsiaII7 Species

    PubMed Central

    Shi, Peiqiong; He, Zhan; Li, Shaojian; An, Xuan; Lv, Ning; Ghanim, Murad; Cuthbertson, Andrew G. S.; Ren, Shun-Xiang

    2016-01-01

    The whitefly Bemisia tabaci is a cosmopolitan insect species complex that harbors the obligate primary symbiont Portiera aleyrodidarum and several facultative secondary symbionts including Wolbachia, which have diverse influences on the host biology. Here, for the first time, we revealed two different localization patterns of Wolbachia present in the immature and adult stages of B. tabaci AsiaII7 cryptic species. In the confined pattern, Wolbachia was restricted to the bacteriocytes, while in the scattered pattern Wolbachia localized in the bacteriocytes, haemolymph and other organs simultaneously. Our results further indicated that, the proportion of B. tabaci AsiaII7 individuals with scattered Wolbachia were significantly lower than that of confined Wolbachia, and the distribution patterns of Wolbachia were not associated with the developmental stage or sex of whitefly host. This study will provide a new insight into the various transmission routes of Wolbachia in different whitefly species. PMID:27611575

  9. Wolbachia Has Two Different Localization Patterns in Whitefly Bemisia tabaci AsiaII7 Species.

    PubMed

    Shi, Peiqiong; He, Zhan; Li, Shaojian; An, Xuan; Lv, Ning; Ghanim, Murad; Cuthbertson, Andrew G S; Ren, Shun-Xiang; Qiu, Bao-Li

    2016-01-01

    The whitefly Bemisia tabaci is a cosmopolitan insect species complex that harbors the obligate primary symbiont Portiera aleyrodidarum and several facultative secondary symbionts including Wolbachia, which have diverse influences on the host biology. Here, for the first time, we revealed two different localization patterns of Wolbachia present in the immature and adult stages of B. tabaci AsiaII7 cryptic species. In the confined pattern, Wolbachia was restricted to the bacteriocytes, while in the scattered pattern Wolbachia localized in the bacteriocytes, haemolymph and other organs simultaneously. Our results further indicated that, the proportion of B. tabaci AsiaII7 individuals with scattered Wolbachia were significantly lower than that of confined Wolbachia, and the distribution patterns of Wolbachia were not associated with the developmental stage or sex of whitefly host. This study will provide a new insight into the various transmission routes of Wolbachia in different whitefly species.

  10. Palaeosymbiosis Revealed by Genomic Fossils of Wolbachia in a Strongyloidean Nematode

    PubMed Central

    Koutsovoulos, Georgios; Makepeace, Benjamin; Tanya, Vincent N.; Blaxter, Mark

    2014-01-01

    Wolbachia are common endosymbionts of terrestrial arthropods, and are also found in nematodes: the animal-parasitic filaria, and the plant-parasite Radopholus similis. Lateral transfer of Wolbachia DNA to the host genome is common. We generated a draft genome sequence for the strongyloidean nematode parasite Dictyocaulus viviparus, the cattle lungworm. In the assembly, we identified nearly 1 Mb of sequence with similarity to Wolbachia. The fragments were unlikely to derive from a live Wolbachia infection: most were short, and the genes were disabled through inactivating mutations. Many fragments were co-assembled with definitively nematode-derived sequence. We found limited evidence of expression of the Wolbachia-derived genes. The D. viviparus Wolbachia genes were most similar to filarial strains and strains from the host-promiscuous clade F. We conclude that D. viviparus was infected by Wolbachia in the past, and that clade F-like symbionts may have been the source of filarial Wolbachia infections. PMID:24901418

  11. Wolbachia Endosymbionts Modify Drosophila Ovary Protein Levels in a Context-Dependent Manner

    PubMed Central

    Christensen, Steen; Pérez Dulzaides, Ricardo; Hedrick, Victoria E.; Momtaz, A. J. M. Zehadee; Nakayasu, Ernesto S.; Paul, Lake N.

    2016-01-01

    ABSTRACT Endosymbiosis is a unique form of interaction between organisms, with one organism dwelling inside the other. One of the most widespread endosymbionts is Wolbachia pipientis, a maternally transmitted bacterium carried by insects, crustaceans, mites, and filarial nematodes. Although candidate proteins that contribute to maternal transmission have been identified, the molecular basis for maternal Wolbachia transmission remains largely unknown. To investigate transmission-related processes in response to Wolbachia infection, ovarian proteomes were analyzed from Wolbachia-infected Drosophila melanogaster and D. simulans. Endogenous and variant host-strain combinations were investigated. Significant and differentially abundant ovarian proteins were detected, indicating substantial regulatory changes in response to Wolbachia. Variant Wolbachia strains were associated with a broader impact on the ovary proteome than endogenous Wolbachia strains. The D. melanogaster ovarian environment also exhibited a higher level of diversity of proteomic responses to Wolbachia than D. simulans. Overall, many Wolbachia-responsive ovarian proteins detected in this study were consistent with expectations from the experimental literature. This suggests that context-specific changes in protein abundance contribute to Wolbachia manipulation of transmission-related mechanisms in oogenesis. IMPORTANCE Millions of insect species naturally carry bacterial endosymbionts called Wolbachia. Wolbachia bacteria are transmitted by females to their offspring through a robust egg-loading mechanism. The molecular basis for Wolbachia transmission remains poorly understood at this time, however. This proteomic study identified specific fruit fly ovarian proteins as being upregulated or downregulated in response to Wolbachia infection. The majority of these protein responses correlated specifically with the type of host and Wolbachia strain involved. This work corroborates previously identified

  12. Breakdown of coevolution between symbiotic bacteria Wolbachia and their filarial hosts.

    PubMed

    Lefoulon, Emilie; Bain, Odile; Makepeace, Benjamin L; d'Haese, Cyrille; Uni, Shigehiko; Martin, Coralie; Gavotte, Laurent

    2016-01-01

    Wolbachia is an alpha-proteobacterial symbiont widely distributed in arthropods. Since the identification of Wolbachia in certain animal-parasitic nematodes (the Onchocercidae or filariae), the relationship between arthropod and nematode Wolbachia has attracted great interest. The obligate symbiosis in filariae, which renders infected species susceptible to antibiotic chemotherapy, was held to be distinct from the Wolbachia-arthropod relationship, typified by reproductive parasitism. While co-evolutionary signatures in Wolbachia-arthropod symbioses are generally weak, reflecting horizontal transmission events, strict co-evolution between filariae and Wolbachia has been reported previously. However, the absence of close outgroups for phylogenetic studies prevented the determination of which host group originally acquired Wolbachia. Here, we present the largest co-phylogenetic analysis of Wolbachia in filariae performed to date including: (i) a screening and an updated phylogeny of Wolbachia; (ii) a co-phylogenetic analysis; and (iii) a hypothesis on the acquisition of Wolbachia infection. First, our results show a general overestimation of Wolbachia occurrence and support the hypothesis of an ancestral absence of infection in the nematode phylum. The accuracy of supergroup J is also underlined. Second, although a global pattern of coevolution remains, the signal is derived predominantly from filarial clades associated with Wolbachia in supergroups C and J. In other filarial clades, harbouring Wolbachia supergroups D and F, horizontal acquisitions and secondary losses are common. Finally, our results suggest that supergroup C is the basal Wolbachia clade within the Ecdysozoa. This hypothesis on the origin of Wolbachia would change drastically our understanding of Wolbachia evolution.

  13. Breakdown of coevolution between symbiotic bacteria Wolbachia and their filarial hosts

    PubMed Central

    Lefoulon, Emilie; Makepeace, Benjamin L.; d’Haese, Cyrille; Uni, Shigehiko; Gavotte, Laurent

    2016-01-01

    Wolbachia is an alpha-proteobacterial symbiont widely distributed in arthropods. Since the identification of Wolbachia in certain animal-parasitic nematodes (the Onchocercidae or filariae), the relationship between arthropod and nematode Wolbachia has attracted great interest. The obligate symbiosis in filariae, which renders infected species susceptible to antibiotic chemotherapy, was held to be distinct from the Wolbachia-arthropod relationship, typified by reproductive parasitism. While co-evolutionary signatures in Wolbachia-arthropod symbioses are generally weak, reflecting horizontal transmission events, strict co-evolution between filariae and Wolbachia has been reported previously. However, the absence of close outgroups for phylogenetic studies prevented the determination of which host group originally acquired Wolbachia. Here, we present the largest co-phylogenetic analysis of Wolbachia in filariae performed to date including: (i) a screening and an updated phylogeny of Wolbachia; (ii) a co-phylogenetic analysis; and (iii) a hypothesis on the acquisition of Wolbachia infection. First, our results show a general overestimation of Wolbachia occurrence and support the hypothesis of an ancestral absence of infection in the nematode phylum. The accuracy of supergroup J is also underlined. Second, although a global pattern of coevolution remains, the signal is derived predominantly from filarial clades associated with Wolbachia in supergroups C and J. In other filarial clades, harbouring Wolbachia supergroups D and F, horizontal acquisitions and secondary losses are common. Finally, our results suggest that supergroup C is the basal Wolbachia clade within the Ecdysozoa. This hypothesis on the origin of Wolbachia would change drastically our understanding of Wolbachia evolution. PMID:27069790

  14. The Native Wolbachia Endosymbionts of Drosophila melanogaster and Culex quinquefasciatus Increase Host Resistance to West Nile Virus Infection

    PubMed Central

    Glaser, Robert L.; Meola, Mark A.

    2010-01-01

    Background The bacterial endosymbiont Wolbachia pipientis has been shown to increase host resistance to viral infection in native Drosophila hosts and in the normally Wolbachia-free heterologous host Aedes aegypti when infected by Wolbachia from Drosophila melanogaster or Aedes albopictus. Wolbachia infection has not yet been demonstrated to increase viral resistance in a native Wolbachia-mosquito host system. Methodology/Principal Findings In this study, we investigated Wolbachia-induced resistance to West Nile virus (WNV; Flaviviridae) by measuring infection susceptibility in Wolbachia-infected and Wolbachia-free D. melanogaster and Culex quinquefasciatus, a natural mosquito vector of WNV. Wolbachia infection of D. melanogaster induces strong resistance to WNV infection. Wolbachia-infected flies had a 500-fold higher ID50 for WNV and produced 100,000-fold lower virus titers compared to flies lacking Wolbachia. The resistance phenotype was transmitted as a maternal, cytoplasmic factor and was fully reverted in flies cured of Wolbachia. Wolbachia infection had much less effect on the susceptibility of D. melanogaster to Chikungunya (Togaviridae) and La Crosse (Bunyaviridae) viruses. Wolbachia also induces resistance to WNV infection in Cx. quinquefasciatus. While Wolbachia had no effect on the overall rate of peroral infection by WNV, Wolbachia-infected mosquitoes produced lower virus titers and had 2 to 3-fold lower rates of virus transmission compared to mosquitoes lacking Wolbachia. Conclusions/Significance This is the first demonstration that Wolbachia can increase resistance to arbovirus infection resulting in decreased virus transmission in a native Wolbachia-mosquito system. The results suggest that Wolbachia reduces vector competence in Cx. quinquefasciatus, and potentially in other Wolbachia-infected mosquito vectors. PMID:20700535

  15. Energy efficient passenger vehicle

    SciTech Connect

    Dessert, R.

    1980-01-01

    An energy efficient passenger carrying vehicle for road use comprised of a long, narrow body carrying two passengers in a back-to-back relationship is described. The vehicle is basically a battery powered electric vehicle that can be charged by all free energy sources; namely, the sun, the wind, human muscles and momentum. The vehicle comprises four modules: body, solar, and two power modules. An electric power module is located within each end of the body module. This module includes electric motors driving the vehicle supporting wheels and rechargeable batteries to power the motors. Pedals, similar to those on a bicycle, located at each power module, drive generators to help recharge the batteries during operation of the vehicle, or directly help drive the vehicle wheels. A solar module comprising a large electricity generating solar cell panel covers most of the vehicle roof to aid in charging the batteries. Means are provided to tilt the solar cell panel toward the sun about a longitudinal axis. A unique flexible duct below the solar panel serves to cool the cells and, if desired, heat the passenger compartment. Further energy savings are obtained by canting the rear wheels while steering with the front wheels, so that the vehicle moves down the road at a crab angle which provides a sail effect when wind is from the vehicle beam or aft of the beam. Regenerative braking means can be used when slowing down, on a long down grade, when sailing speed is greater than required, or any other time when vehicle momentum is greater than necessary for vehicle operation, to use the excess forward momentum to drive generators to charge the batteries. Thus, a single battery charge will be conserved and vehicle operation will be assisted in a manner giving maximum vehicle range and speed.

  16. Energy efficient passenger vehicle

    SciTech Connect

    Dessert, R.

    1983-02-22

    An energy efficient passenger carrying vehicle for road use. The vehicle basically comprises a long, narrow body carrying two passengers in a back-to-back relationship. The vehicle is basically a battery powered electric vehicle that can be charged by all free energy sources; namely, the sun, the wind, human muscles and momentum. The vehicle comprises four modules, namely body, solar, and two power modules. An electric power module is located within each end of the body module. This module includes electric motors driving the vehicle supporting wheels and rechargeable batteries to power the motors. Pedals, similar to those on a bicycle, located at each power module, drive generators to help recharge the batteries during operation of the vehicle, or directly help drive the vehicle wheels. A solar module comprising a large electricity generating solar cell panel covers most of the vehicle roof to aid in charging the batteries. Means are provided to tilt the solar cell panel toward the sun about a longitudinal axis. A unique flexible duct below the solar panel serves to cool the cells and, if desired, heat the passenger compartment. Further energy savings are obtained by canting the rear wheels while steering with the front wheels, so that the vehicle moves down the road at a crab angle which provides a sail effect when wind is from the vehicle beam or aft of the beam. Regenerative braking means can be used when slowing down, on a long down grade, when sailing speed is greater than required, or any other time when vehicle momentum is greater than necessary for vehicle operation, to use the excess forward momentum to drive generators to charge the batteries. Thus, a single battery charge will be conserved and vehicle operation will be assisted in a manner giving maximum vehicle range and speed.

  17. The distribution of Wolbachia in fig wasps: correlations with host phylogeny, ecology and population structure.

    PubMed Central

    Shoemaker, D DeWayne; Machado, Carlos A; Molbo, Drude; Werren, John H; Windsor, Donald M; Herre, Edward Allen

    2002-01-01

    We surveyed for the presence and identity of Wolbachia in 44 species of chalcid wasps associated with 18 species of Panamanian figs. We used existing detailed knowledge of the population structures of the host wasps, as well as the ecological and evolutionary relationships among them, to explore the relevance of each of these factors to Wolbachia prevalence and mode of transmission. Fifty-nine per cent of these wasp species have Wolbachia infections, the highest proportion reported for any group of insects. Further, neither the presence nor the frequency of Wolbachia within hosts was correlated with the population structure of pollinator hosts. Phylogenetic analyses of wsp sequence data from 70 individuals representing 22 wasp species show that neither the close phylogenetic relationship nor close ecological association among host species is consistently linked to close phylogenetic affinities of the Wolbachia associated with them. Moreover, no genetic variation was detected within any Wolbachia strain from a given host species. Thus, the spread of Wolbachia within host species exceeds the rate of horizontal transmission among species and both exceed the rate of mutation of the wsp gene in Wolbachia. The presence and, in some cases, high frequency of Wolbachia infections within highly inbred species indicate that the Wolbachia either directly increase host fitness or are frequently horizontally transferred within these wasp species. However, the paucity of cospeciation of Wolbachia and their wasp hosts indicates that Wolbachia do not persist within a given host lineage for long time-periods relative to speciation times. PMID:12427319

  18. Costs and benefits of Wolbachia infection in immature Aedes albopictus depend upon sex and competition level.

    PubMed

    Gavotte, Laurent; Mercer, David R; Stoeckle, John J; Dobson, Stephen L

    2010-11-01

    Bacterial endosymbionts induce various effects on hosts and can dramatically impact host fitness and development. An example is provided by obligate, maternally-inherited Wolbachia, which infect a broad range of invertebrates. Wolbachia are capable of altering host reproduction, thereby promoting infection spread. Wolbachia also pose direct physiological costs and benefits to hosts, complicating their categorization as parasites or mutualists. This study examines for an effect of Wolbachia infection in intra-specific larval competition by Aedes albopictus mosquitoes, with the goal of examining for an impact of Wolbachia infection in mixed populations. Similar to prior work examining for an influence of Wolbachia infection on the fitness of A. albopictus in adults, the results presented here support the hypothesized impact of Wolbachia across all life stages, including immatures. The differential competitiveness of infected larvae detected in our experiments indicates that Wolbachia infected A. albopictus females are less competitive relative to uninfected females when competing under highly competitive conditions. In contrast, under low competitive pressures, infected females experience higher survivorship. Thus, Wolbachia infection shifts from parasitism to mutualism as a function of developmental conditions. Results are discussed in relation to the invasion and persistence of Wolbachia in A. albopictus populations. The results are important to the evolution of stable Wolbachia symbioses, including Wolbachia invasion of an uninfected population. The resulting infection dynamics that occur in an infected population are discussed.

  19. Cytonuclear Epistasis Controls the Density of Symbiont Wolbachia pipientis in Nongonadal Tissues of Mosquito Culex quinquefasciatus.

    PubMed

    Emerson, Kevin J; Glaser, Robert L

    2017-08-07

    Wolbachia pipientis, a bacterial symbiont infecting arthropods and nematodes, is vertically transmitted through the female germline and manipulates its host's reproduction to favor infected females. Wolbachia also infects somatic tissues where it can cause nonreproductive phenotypes in its host, including resistance to viral pathogens. Wolbachia-mediated phenotypes are strongly associated with the density of Wolbachia in host tissues. Little is known, however, about how Wolbachia density is regulated in native or heterologous hosts. Here, we measure the broad-sense heritability of Wolbachia density among families in field populations of the mosquito Culex pipiens, and show that densities in ovary and nongonadal tissues of females in the same family are not correlated, suggesting that Wolbachia density is determined by distinct mechanisms in the two tissues. Using introgression analysis between two different strains of the closely related species C. quinquefasciatus, we show that Wolbachia densities in ovary tissues are determined primarily by cytoplasmic genotype, while densities in nongonadal tissues are determined by both cytoplasmic and nuclear genotypes and their epistatic interactions. Quantitative-trait-locus mapping identified two major-effect quantitative-trait loci in the C. quinquefasciatus genome explaining a combined 23% of variance in Wolbachia density, specifically in nongonadal tissues. A better understanding of how Wolbachia density is regulated will provide insights into how Wolbachia density can vary spatiotemporally in insect populations, leading to changes in Wolbachia-mediated phenotypes such as viral pathogen resistance. Copyright © 2017 Emerson, Glaser.

  20. Cytonuclear Epistasis Controls the Density of Symbiont Wolbachia pipientis in Nongonadal Tissues of Mosquito Culex quinquefasciatus

    PubMed Central

    Emerson, Kevin J.; Glaser, Robert L.

    2017-01-01

    Wolbachia pipientis, a bacterial symbiont infecting arthropods and nematodes, is vertically transmitted through the female germline and manipulates its host’s reproduction to favor infected females. Wolbachia also infects somatic tissues where it can cause nonreproductive phenotypes in its host, including resistance to viral pathogens. Wolbachia-mediated phenotypes are strongly associated with the density of Wolbachia in host tissues. Little is known, however, about how Wolbachia density is regulated in native or heterologous hosts. Here, we measure the broad-sense heritability of Wolbachia density among families in field populations of the mosquito Culex pipiens, and show that densities in ovary and nongonadal tissues of females in the same family are not correlated, suggesting that Wolbachia density is determined by distinct mechanisms in the two tissues. Using introgression analysis between two different strains of the closely related species C. quinquefasciatus, we show that Wolbachia densities in ovary tissues are determined primarily by cytoplasmic genotype, while densities in nongonadal tissues are determined by both cytoplasmic and nuclear genotypes and their epistatic interactions. Quantitative-trait-locus mapping identified two major-effect quantitative-trait loci in the C. quinquefasciatus genome explaining a combined 23% of variance in Wolbachia density, specifically in nongonadal tissues. A better understanding of how Wolbachia density is regulated will provide insights into how Wolbachia density can vary spatiotemporally in insect populations, leading to changes in Wolbachia-mediated phenotypes such as viral pathogen resistance. PMID:28606944

  1. Obligatory symbiotic Wolbachia endobacteria are absent from Loa loa

    PubMed Central

    Büttner, Dietrich W; Wanji, Samuel; Bazzocchi, Chiara; Bain, Odile; Fischer, Peter

    2003-01-01

    Background Many filarial nematodes harbour Wolbachia endobacteria. These endobacteria are transmitted vertically from one generation to the next. In several filarial species that have been studied to date they are obligatory symbionts of their hosts. Elimination of the endobacteria by antibiotics interrupts the embryogenesis and hence the production of microfilariae. The medical implication of this being that the use of doxycycline for the treatment of human onchocerciasis and bancroftian filariasis leads to elimination of the Wolbachia and hence sterilisation of the female worms. Wolbachia play a role in the immunopathology of patients and may contribute to side effects seen after antifilarial chemotherapy. In several studies Wolbachia were not observed in Loa loa. Since these results have been doubted, and because of the medical significance, several independent methods were applied to search for Wolbachia in L. loa. Methods Loa loa and Onchocerca volvulus were studied by electron microscopy, histology with silver staining, and immunohistology using antibodies against WSP, Wolbachia aspartate aminotransferase, and heat shock protein 60. The results achieved with L. loa and O. volvulus were compared. Searching for Wolbachia, genes were amplified by PCR coding for the bacterial 16S rDNA, the FTSZ cell division protein, and WSP. Results No Wolbachia endobacteria were discovered by immunohistology in 13 male and 14 female L. loa worms and in numerous L. loa microfilariae. In contrast, endobacteria were found in large numbers in O. volvulus and 14 other filaria species. No intracellular bacteria were seen in electron micrographs of oocytes and young morulae of L. loa in contrast to O. volvulus. In agreement with these results, Wolbachia DNA was not detected by PCR in three male and six female L. loa worms and in two microfilariae samples of L. loa. Conclusions Loa loa do not harbour obligatory symbiotic Wolbachia endobacteria in essential numbers to enable their

  2. Passenger distractions among adolescent drivers.

    PubMed

    Heck, Katherine E; Carlos, Ramona M

    2008-01-01

    Adolescents who drive with peers are known to have a higher risk of crashes. While passengers may distract drivers, little is known about the circumstances of these distractions among teen drivers. This study used survey data on driving among 2,144 California high school seniors to examine distractions caused by passengers. Overall, 38.4% of youths who drove reported having been distracted by a passenger. Distractions were more commonly reported among girls and students attending moderate- to high-income schools. Talking or yelling was the most commonly reported type of distraction. About 7.5% of distractions reported were deliberate, such as hitting or tickling the driver or attempting to use the vehicle's controls. Driving after alcohol use and having had a crash as a driver were both significant predictors of reporting passenger-related distraction. Adolescents often experience distractions related to passengers, and in some cases these distractions are intentional. These results provide information about teenage drivers who are distracted by passenger behaviors. In some cases, passengers attempted to use vehicle controls; however, it seems unlikely that this behavior is common enough to warrant redesign of controls to make them less accessible to passengers.

  3. Wolbachia Induces Density-Dependent Inhibition to Dengue Virus in Mosquito Cells

    PubMed Central

    Lu, Peng; Bian, Guowu; Pan, Xiaoling; Xi, Zhiyong

    2012-01-01

    Wolbachia is a maternal transmitted endosymbiotic bacterium that is estimated to infect up to 65% of insect species. The ability of Wolbachia to both induce viral interference and spread into mosquito vector population makes it possible to develop Wolbachia as a biological control agent for dengue control. While Wolbachia induces resistance to dengue virus in the transinfected Aedes aegypti mosquitoes, a similar effect was not observed in Aedes albopictus, which naturally carries Wolbachia infection but still serves as a dengue vector. In order to understand the mechanism of this lack of Wolbachia-mediated viral interference, we used both Ae. albopictus cell line (Aa23) and mosquitoes to characterize the impact of Wolbachia on dengue infection. A serial of sub-lethal doses of antibiotic treatment was used to partially remove Wolbachia in Aa23 cells and generate cell cultures with Wolbachia at different densities. We show that there is a strong negative linear correlation between the genome copy of Wolbachia and dengue virus with a dengue infection completely removed when Wolbacha density reaches a certain level. We then compared Wolbachia density between transinfected Ae. aegypti and naturally infected Ae. albopictus. The results show that Wolbachia density in midgut, fatbody and salivary gland of Ae. albopictus is 80-, 18-, and 24-fold less than that of Ae. aegypti, respectively. We provide evidence that Wolbachia density in somatic tissues of Ae. albopictus is too low to induce resistance to dengue virus. Our results will aid in understanding the mechanism of Wolbachia-mediated pathogen interference and developing novel methods to block disease transmission by mosquitoes carrying native Wolbachia infections. PMID:22848774

  4. Molecular evidence of Wolbachia infection in natural populations of tropical odonates.

    PubMed

    Thipaksorn, Apisit; Jamnongluk, Wanwisa; Kittayapong, Pattamaporn

    2003-10-01

    Wolbachia are endosymbiotic bacteria that cause reproductive alterations in numerous arthropod species. Using a PCR-based method, we found that, out of 33 odonate species, four species were infected with Wolbachia. This finding represents the first record of Wolbachia infection in tropical odonates. Identical wsp gene sequences were found in the Wolbachia-infected common odonate species, Agriocnemis f. femina, collected from different locations in Thailand. The infection frequencies in several natural populations suggest that replacement of uninfected populations by Wolbachia-infected ones has recently occurred in this damselfly species.

  5. Human filarial Wolbachia lipopeptide directly activates human neutrophils in vitro

    PubMed Central

    Tamarozzi, F; Wright, H L; Johnston, K L; Edwards, S W; Turner, J D; Taylor, M J

    2014-01-01

    The host inflammatory response to the Onchocerca volvulus endosymbiont, Wolbachia, is a major contributing factor in the development of chronic pathology in humans (onchocerciasis/river blindness). Recently, the toll-like pattern recognition receptor motif of the major inflammatory ligands of filarial Wolbachia, membrane-associated diacylated lipoproteins, was functionally defined in murine models of pathology, including mediation of neutrophil recruitment to the cornea. However, the extent to which human neutrophils can be activated in response to this Wolbachia pattern recognition motif is not known. Therefore, the responses of purified peripheral blood human neutrophils to a synthetic N-terminal diacylated lipopeptide (WoLP) of filarial Wolbachia peptidoglycan-associated lipoprotein (PAL) were characterized. WoLP exposure led to a dose-dependent activation of healthy, human neutrophils that included gross morphological alterations and modulation of surface expressed integrins involved in tethering, rolling and extravasation. WoLP exposure induced chemotaxis but not chemokinesis of neutrophils, and secretion of the major neutrophil chemokine, interleukin 8. WoLP also induced and primed the respiratory burst, and enhanced neutrophil survival by delay of apoptosis. These results indicate that the major inflammatory motif of filarial Wolbachia lipoproteins directly activates human neutrophils in vitro and promotes a molecular pathway by which human neutrophils are recruited to sites of Onchocerca parasitism. PMID:24909063

  6. Infections of Wolbachia may destabilize mosquito population dynamics.

    PubMed

    Telschow, Arndt; Grziwotz, Florian; Crain, Philip; Miki, Takeshi; Mains, James W; Sugihara, George; Dobson, Stephen L; Hsieh, Chih-Hao

    2017-09-07

    Recent efforts in controlling mosquito-borne diseases focus on biocontrol strategies that incapacitate pathogens inside mosquitoes by altering the mosquito's microbiome. A case in point is the introduction of Wolbachia into natural mosquito populations in order to eliminate Dengue virus. However, whether this strategy can successfully control vector-borne diseases is debated; particularly, how artificial infection affects population dynamics of hosts remains unclear. Here, we show that natural Wolbachia infections are associated with unstable mosquito population dynamics by contrasting Wolbachia-infected versus uninfected cage populations of the Asian tiger mosquito (Aedes albopictus). By analyzing weekly data of adult mosquito abundances, we found that the variability of the infected populations is significantly higher than that of the uninfected. The elevated population variability is explained by increased instability in dynamics, as quantified by system nonlinearity (i.e., state-dependence). In addition, predictability of infected populations is substantially lower. A mathematical model analysis suggests that Wolbachia may alter mosquito population dynamics by modifying larval competition of hosts. These results encourage examination for effects of artificial Wolbachia establishment on mosquito populations, because an enhancement of population variability with reduced predictability could pose challenges in management. Our findings have implications for application of microbiome alterations in biocontrol programs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Human filarial Wolbachia lipopeptide directly activates human neutrophils in vitro.

    PubMed

    Tamarozzi, F; Wright, H L; Johnston, K L; Edwards, S W; Turner, J D; Taylor, M J

    2014-10-01

    The host inflammatory response to the Onchocerca volvulus endosymbiont, Wolbachia, is a major contributing factor in the development of chronic pathology in humans (onchocerciasis/river blindness). Recently, the toll-like pattern recognition receptor motif of the major inflammatory ligands of filarial Wolbachia, membrane-associated diacylated lipoproteins, was functionally defined in murine models of pathology, including mediation of neutrophil recruitment to the cornea. However, the extent to which human neutrophils can be activated in response to this Wolbachia pattern recognition motif is not known. Therefore, the responses of purified peripheral blood human neutrophils to a synthetic N-terminal diacylated lipopeptide (WoLP) of filarial Wolbachia peptidoglycan-associated lipoprotein (PAL) were characterized. WoLP exposure led to a dose-dependent activation of healthy, human neutrophils that included gross morphological alterations and modulation of surface expressed integrins involved in tethering, rolling and extravasation. WoLP exposure induced chemotaxis but not chemokinesis of neutrophils, and secretion of the major neutrophil chemokine, interleukin 8. WoLP also induced and primed the respiratory burst, and enhanced neutrophil survival by delay of apoptosis. These results indicate that the major inflammatory motif of filarial Wolbachia lipoproteins directly activates human neutrophils in vitro and promotes a molecular pathway by which human neutrophils are recruited to sites of Onchocerca parasitism. © 2014 The Authors. Parasite Immunology Published by John Wiley & Sons Ltd.

  8. New Wolbachia supergroups detected in quill mites (Acari: Syringophilidae).

    PubMed

    Glowska, Eliza; Dragun-Damian, Anna; Dabert, Miroslawa; Gerth, Michael

    2015-03-01

    Wolbachia is the most abundant intracellular bacterial genus infecting a wide range of arthropods and filarial nematodes. Wolbachia have evolved parasitic, mutualistic and commensal relationships with their hosts but in arthropods generally act as reproductive parasites, inducing a wide range of phenotypic effects such as cytoplasmic incompatibility, parthenogenesis, feminization and male-killing. Up to now, the genus has been divided into 14 supergroups successively named A-O. Here, we describe two new Wolbachia supergroups from syringophilid mites (Acari: Cheyletoidea). These obligatory ectoparasites of birds inhabit the quills of feathers in many avian groups. The species of this family reproduce in a haplodiploid mode sensu arrhenotoky and are usually strongly female-biased. Based on the sequences of four protein-coding genes (ftsZ, gltA and groEL and coxA) and the 16S rRNA we identified strains of three Wolbachia supergroups (F and two distinct, yet undescribed ones) in five quill mite species. Our results suggest that in some cases the distribution of the bacteria can be better correlated with the mite's bird host rather than with mite taxonomy as such. The discovery of two new Wolbachia supergroups not only broadens the knowledge of the diversity of this bacterium but also raises questions about potential effects induced in quill mites and transmission mechanisms of the endosymbionts in this peculiar bacteria-quill mite-bird system. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Wolbachia Infection in a Natural Parasitoid Wasp Population.

    PubMed

    Duplouy, Anne; Couchoux, Christelle; Hanski, Ilkka; van Nouhuys, Saskya

    2015-01-01

    The maternally transmitted bacterium Wolbachia pipientis is well known for spreading and persisting in insect populations through manipulation of the fitness of its host. Here, we identify three new Wolbachia pipientis strains, wHho, wHho2 and wHho3, infecting Hyposoter horticola, a specialist wasp parasitoid of the Glanville fritillary butterfly. The wHho strain (ST435) infects about 50% of the individuals in the Åland islands in Finland, with a different infection rate in the two mitochondrial (COI) haplotypes of the wasp. The vertical transmission rate of Wolbachia is imperfect, and lower in the haplotype with lower infection rate, suggesting a fitness trade-off. We found no association of the wHho infection with fecundity, longevity or dispersal ability of the parasitoid host. However, preliminary results convey spatial associations between Wolbachia infection, host mitochondrial haplotype and parasitism of H. horticola by its hyperparasitoid, Mesochorus cf. stigmaticus. We discuss the possibility that Wolbachia infection protects H. horticola against hyperparasitism.

  10. Depletion of host cell riboflavin reduces Wolbachia levels in cultured mosquito cells

    PubMed Central

    Baldridge, Gerald D.; Carroll, Elissa M.; Kurtz, Cassandra M.

    2015-01-01

    Wolbachia is an obligate intracellular alphaproteobacterium that occurs in arthropod and nematode hosts. Wolbachia presumably provides a fitness benefit to its hosts, but the basis for its retention and spread in host populations remains unclear. Wolbachia genomes retain biosynthetic pathways for some vitamins, and the possibility that these vitamins benefit host cells provides a potential means of selecting for Wolbachia-infected cell lines. To explore whether riboflavin produced by Wolbachia is available to its host cell, we established that growth of uninfected C7–10 mosquito cells decreases in riboflavin-depleted culture medium. A well studied inhibitor of riboflavin uptake, lumiflavin, further inhibits growth of uninfected C7–10 cells with an LC50 of approximately 12 µg/ml. Growth of C/wStr1 mosquito cells, infected with Wolbachia from the planthopper, Laodelphax striatellus, was enhanced in medium containing low levels of lumiflavin, but Wolbachia levels decreased. Lumiflavin-enhanced growth thus resembled the improved growth that accompanies treatment with antibiotics that deplete Wolbachia, rather than a metabolic advantage provided by the Wolbachia infection. We used the polymerase chain reaction to validate the decrease in Wolbachia abundance and evaluated our results in the context of a proteomic analysis in which we detected nearly 800 wStr proteins. Our data indicate that Wolbachia converts riboflavin to FMN and FAD for its own metabolic needs, and does not provide a source of riboflavin for its host cell. PMID:24789726

  11. Flow cytometric evaluation of the intracellular bacterium, Wolbachia pipientis, in mosquito cells

    PubMed Central

    Fallon, Ann M

    2014-01-01

    Wolbachia is an obligate intracellular bacterium (Anaplasmataceae, Rickettisales) that occurs in arthropods and filarial worms, and spreads by vertical transmission in the oocyte cytoplasm. In insects, reproductive distortions associated with Wolbachia, such as cytoplasmic incompatibility in mosquitoes, have potential value for controlling pests, including species that transmit human, animal and plant diseases. Wolbachia strains that propagate as a persistent infection in insect cell lines provide an important resource for developing the genetic tools that will facilitate these applications. Here I describe conditions for flow cytometric evaluation of Wolbachia growth in persistently infected mosquito cells. Cytometry parameters were established using uninfected mosquito cells and Escherichia coli as a surrogate for Wolbachia, and quantitation was correlated with cell counts determined with a Coulter electronic cell counter and bacterial counts based on optical density. The protocol was validated by showing depletion of Wolbachia in medium containing tetracycline and rifampicin, and sensitivity of Wolbachia to treatment of host cells with paraquat, an oxidizing agent, and lumiflavin, an inhibitor of riboflavin uptake. The Wolbachia peak on the flow cytometry histogram was shown to contain Wolbachia by DNA analysis using the polymerase chain reaction, and by infection of naive recipient cells. This approach will streamline investigation of Wolbachia growth in insect cell lines and facilitate identification of culture conditions that select for Wolbachia-infected cells. PMID:25300665

  12. Depletion of host cell riboflavin reduces Wolbachia levels in cultured mosquito cells.

    PubMed

    Fallon, Ann M; Baldridge, Gerald D; Carroll, Elissa M; Kurtz, Cassandra M

    2014-09-01

    Wolbachia is an obligate intracellular alphaproteobacterium that occurs in arthropod and nematode hosts. Wolbachia presumably provides a fitness benefit to its hosts, but the basis for its retention and spread in host populations remains unclear. Wolbachia genomes retain biosynthetic pathways for some vitamins, and the possibility that these vitamins benefit host cells provides a potential means of selecting for Wolbachia-infected cell lines. To explore whether riboflavin produced by Wolbachia is available to its host cell, we established that growth of uninfected C7-10 mosquito cells decreases in riboflavin-depleted culture medium. A well-studied inhibitor of riboflavin uptake, lumiflavin, further inhibits growth of uninfected C7-10 cells with an LC50 of approximately 12 μg/ml. Growth of C/wStr1 mosquito cells, infected with Wolbachia from the planthopper, Laodelphax striatellus, was enhanced in medium containing low levels of lumiflavin, but Wolbachia levels decreased. Lumiflavin-enhanced growth thus resembled the improved growth that accompanies treatment with antibiotics that deplete Wolbachia, rather than a metabolic advantage provided by the Wolbachia infection. We used the polymerase chain reaction to validate the decrease in Wolbachia abundance and evaluated our results in the context of a proteomic analysis in which we detected nearly 800 wStr proteins. Our data indicate that Wolbachia converts riboflavin to FMN and FAD for its own metabolic needs, and does not provide a source of riboflavin for its host cell.

  13. Wolbachia density changes seasonally amongst populations of the pale grass blue butterfly, Zizeeria maha (Lepidoptera: Lycaenidae).

    PubMed

    Sumi, Takuto; Miura, Kazuki; Miyatake, Takahisa

    2017-01-01

    Previous studies showed that the survival rate of Wolbachia decreases under high temperature in incubators. It is also known that a high density of Wolbachia in the host body reduces the host emergence rate, while low densities fail to change reproduction rates. However, few studies have examined the density of Wolbachia in hosts in the field. Here, we focus on Wolbachia infection of the pale grass blue butterfly, Zizeeria maha (Lepidoptera: Lycaenidae), which is distributed throughout the Japanese islands. We examined the rate and density of Wolbachia infection in the bodies of butterflies at thirteen locations in Japan. At seven of these places, we collected butterflies in different seasons to determine seasonal differences in the infection rate and density and found that Wolbachia density has seasonal differences within the same population. Moreover, to determine whether Wolbachia density has a geographical cline, we compared the infection density of Wolbachia amongst all geographical populations. In addition, we determined the sequences of Wolbachia wsp and host mtDNA CO1 haplotypes of all populations. The results showed that Wolbachia density increased in early summer and decreased in autumn. Further, the density of Wolbachia infecting the same strain of Z. maha varied amongst populations, although no tendency in geographical cline was observed.

  14. Wolbachia density changes seasonally amongst populations of the pale grass blue butterfly, Zizeeria maha (Lepidoptera: Lycaenidae)

    PubMed Central

    Sumi, Takuto; Miura, Kazuki; Miyatake, Takahisa

    2017-01-01

    Previous studies showed that the survival rate of Wolbachia decreases under high temperature in incubators. It is also known that a high density of Wolbachia in the host body reduces the host emergence rate, while low densities fail to change reproduction rates. However, few studies have examined the density of Wolbachia in hosts in the field. Here, we focus on Wolbachia infection of the pale grass blue butterfly, Zizeeria maha (Lepidoptera: Lycaenidae), which is distributed throughout the Japanese islands. We examined the rate and density of Wolbachia infection in the bodies of butterflies at thirteen locations in Japan. At seven of these places, we collected butterflies in different seasons to determine seasonal differences in the infection rate and density and found that Wolbachia density has seasonal differences within the same population. Moreover, to determine whether Wolbachia density has a geographical cline, we compared the infection density of Wolbachia amongst all geographical populations. In addition, we determined the sequences of Wolbachia wsp and host mtDNA CO1 haplotypes of all populations. The results showed that Wolbachia density increased in early summer and decreased in autumn. Further, the density of Wolbachia infecting the same strain of Z. maha varied amongst populations, although no tendency in geographical cline was observed. PMID:28403227

  15. A Wolbachia-Sensitive Communication between Male and Female Pupae Controls Gamete Compatibility in Drosophila.

    PubMed

    Pontier, Stéphanie M; Schweisguth, François

    2015-09-21

    Gamete compatibility is fundamental to sexual reproduction. Wolbachia are maternally inherited endosymbiotic bacteria that manipulate gamete compatibility in many arthropod species. In Drosophila, the fertilization of uninfected eggs by sperm from Wolbachia-infected males often results in early developmental arrest. This gamete incompatibility is called cytoplasmic incompatibility (CI). CI is highest in young males, suggesting that Wolbachia affect sperm properties during male development. Here, we show that Wolbachia modulate testis development. Unexpectedly, this effect was associated with Wolbachia infection in females, not males. This raised the possibility that females influenced testis development by communicating with males prior to adulthood. Using a combinatorial rearing protocol, we provide evidence for such a female-to-male communication during metamorphosis. This communication involves the perception of female pheromones by male olfactory receptors. We found that this communication determines the compatibility range of sperm. Wolbachia interfere with this female-to-male communication through changes in female pheromone production. Strikingly, restoring this communication partially suppressed CI in Wolbachia-infected males. We further identified a reciprocal male-to-female communication at metamorphosis that restricts the compatibility range of female gametes. Wolbachia also perturb this communication by feminizing male pheromone production. Thus, Wolbachia broaden the compatibility range of eggs, promoting thereby the reproductive success of Wolbachia-infected females. We conclude that pheromone communication between pupae regulates gamete compatibility and is sensitive to Wolbachia in Drosophila. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. [Presumptive role of Wolbachia in deltamethrin resistance of Culex pipiens pallens].

    PubMed

    Hong, Shan-Chao; Lv, Yuan; Fang, Fu-Jin; Zhu, Chang-Liang

    2014-12-01

    To investigate the relationship between Wolbachia and deltamethrin resistance in Culex pipiens pallens. PCR was used to detect Wolbachia in Culex pipiens pallens and qRT-PCR was performed to determine and compare the expression of Wolbachia between deltamethrin- resistant and - susceptible strains of Culex pipiens pallens. Wolbachia was detected in Culex pipiens pallens in the laboratory. The expression of Wolbachia was 18.42, 3.69, 4.43, 3.96, 6.31, 1.55 and 3.76 folds higher in the deltamethrin-resistant strain than in susceptible strain in the egg, 1st, 2nd, 3rd, 4th stages, and male and female adults, but there was no statistical difference in the pupae stage. The expression of Wolbachia was 2.64 folds higher in deltamethrin-resistant females than in susceptible females which were caught in Jiangxinzhou of Nanjing. Wolbachia is associated with deltamethrin resistance in Culex pipines pallens.

  17. Bacteriophage WO Can Mediate Horizontal Gene Transfer in Endosymbiotic Wolbachia Genomes

    PubMed Central

    Wang, Guan H.; Sun, Bao F.; Xiong, Tuan L.; Wang, Yan K.; Murfin, Kristen E.; Xiao, Jin H.; Huang, Da W.

    2016-01-01

    Phage-mediated horizontal gene transfer (HGT) is common in free-living bacteria, and many transferred genes can play a significant role in their new bacterial hosts. However, there are few reports concerning phage-mediated HGT in endosymbionts (obligate intracellular bacteria within animal or plant hosts), such as Wolbachia. The Wolbachia-infecting temperate phage WO can actively shift among Wolbachia genomes and has the potential to mediate HGT between Wolbachia strains. In the present study, we extend previous findings by validating that the phage WO can mediate transfer of non-phage genes. To do so, we utilized bioinformatic, phylogenetic, and molecular analyses based on all sequenced Wolbachia and phage WO genomes. Our results show that the phage WO can mediate HGT between Wolbachia strains, regardless of whether the transferred genes originate from Wolbachia or other unrelated bacteria. PMID:27965627

  18. Detection of Wolbachia from field collected Aedes albopictus Skuse in Malaysia

    PubMed Central

    Afizah, A. Noor; Roziah, A.; Nazni, W.A.; Lee, H.L.

    2015-01-01

    Background & objectives: Wolbachia-based vector control strategies have been proposed as a mean to augment the existing measures for controlling dengue vector. Prior to utilizing Wolbachia in novel vector control strategies, it is crucial to understand the Wolbachia-mosquito interactions. Many studies have only focused on the prevalence of Wolbachia in female Aedes albopictus with lack of attention on Wolbachia infection on the male Ae. albopictus which also affects the effective expression of Wolbachia induced- cytoplasmic incompatibility (CI). In this study, field surveys were conducted to screen for the infection status of Wolbachia in female and male Ae. albopictus from various habitats including housing areas, islands and seashore. Methods: Adult Ae. albopictus (n=104) were collected using human landing catches and hand aspirator. Standard ovitraps were also set in the selected areas for five days and the larvae were identified to species level. All the collected Ae. albopictus were screened for the presence of Wolbachia using multiplex polymerase chain reaction (PCR) and gene sequencing of Wolbachia surface protein (wsp) gene. Results: A 100 per cent positivity of Wolbachia infection was observed for individual Ae. albopictus screened. For pooled mosquitoes, 73 of the 76 pools (female) and 83 of the 87 pools (male) were positive with Wolbachia infection. The wsp gene sequence of the Wolbachia strain isolated from individual and pooled mosquitoes showed a 100 per cent homology with Wolbachia sp. of Ae. albopictus isolated from various geographical regions. Phylogenetic analysis based on wsp gene fragments showed that the isolates were clustered into groups A and B, respectively. Interpretation & conclusions: The results indicated that Wolbachia infection was widespread in Ae. albopictus population both in female and male Ae. albopictus. All the infected females were superinfected with both A and B strains while the infected males showed a combination of

  19. Detection of Wolbachia from field collected Aedes albopictus Skuse in Malaysia.

    PubMed

    Noor Afizah, A; Roziah, A; Nazni, W A; Lee, H L

    2015-08-01

    Wolbachia-based vector control strategies have been proposed as a mean to augment the existing measures for controlling dengue vector. Prior to utilizing Wolbachia in novel vector control strategies, it is crucial to understand the Wolbachia-mosquito interactions. Many studies have only focused on the prevalence of Wolbachia in female Aedes albopictus with lack of attention on Wolbachia infection on the male Ae. albopictus which also affects the effective expression of Wolbachia induced- cytoplasmic incompatibility (CI). In this study, field surveys were conducted to screen for the infection status of Wolbachia in female and male Ae. albopictus from various habitats including housing areas, islands and seashore. Adult Ae. albopictus (n=104) were collected using human landing catches and hand aspirator. Standard ovitraps were also set in the selected areas for five days and the larvae were identified to species level. All the collected Ae. albopictus were screened for the presence of Wolbachia using multiplex polymerase chain reaction (PCR) and gene sequencing of Wolbachia surface protein (wsp) gene. A 100 per cent positivity of Wolbachia infection was observed for individual Ae. albopictus screened. For pooled mosquitoes, 73 of the 76 pools (female) and 83 of the 87 pools (male) were positive with Wolbachia infection. The wsp gene sequence of the Wolbachia strain isolated from individual and pooled mosquitoes showed a 100 per cent homology with Wolbachia sp. of Ae. albopictus isolated from various geographical regions. Phylogenetic analysis based on wsp gene fragments showed that the isolates were clustered into groups A and B, respectively. The results indicated that Wolbachia infection was widespread in Ae. albopictus population both in female and male Ae. albopictus. All the infected females were superinfected with both A and B strains while the infected males showed a combination of superinfection of A and B strains and single infection of B strain.

  20. Transfer of a parthenogenesis-inducing Wolbachia endosymbiont derived from Trichogramma dendrolimi into Trichogramma evanescens.

    PubMed

    Watanabe, Masaya; Kageyama, Daisuke; Miura, Kazuki

    2013-01-01

    Wolbachia, which are maternally transmitted endosymbionts, are considered to have moved horizontally between invertebrate hosts multiple times. However, it is not well understood how easily Wolbachia are transmitted horizontally between different hosts and how frequently horizontally-transmitted Wolbachia become established in their new hosts. We transferred a parthenogenesis-inducing Wolbachia endosymbiont derived from the parasitic wasp Trichogramma dendrolimi to Trichogramma evanescens. Specifically, Wolbachia was cultivated in a mosquito cell line and the Wolbachia-infected cells were microinjected into uninfected T. evanescens. Among 276 pupae inoculated with Wolbachia-infected cells, 65 adults emerged (G0). Diagnostic PCR demonstrated that 25 of 37 G0 females (68%) were Wolbachia-positive. Among isofemale lines established from G0 females, the proportions of infected lines were 80% (20 of 25) in G1 and 100% (18 of 18) in G2. In an isofemale line, infection was stably maintained for more than 10 generations. These results indicate invasion of Wolbachia into the germline of the recipient insect. Quantitative PCR demonstrated that the Wolbachia titer in the recipient host was significantly lower than that in the native host. The absence or very low number, if any, of parthenogenetically-reproducing individuals in the recipient host may be caused by the low Wolbachia titer. The Wolbachia titer in the recipients was lower in G11 than in G5, suggesting a decline in the density. Together with a previous report, our study may imply that Wolbachia in Trichogramma species are highly adapted to their hosts, which hinders robust expression of the Wolbachia phenotype in non-native host species.

  1. Phage WO of Wolbachia: lambda of the endosymbiont world

    PubMed Central

    Kent, Bethany N.; Bordenstein, Seth R.

    2010-01-01

    The discovery of an extraordinarily high level of mobile elements in the genome of Wolbachia, a widespread arthropod and nematode endosymbiont, suggests that this bacterium could be an excellent model for assessing the evolution and function of mobile DNA in specialized bacteria. Here, we discuss how studies on the temperate bacteriophage WO of Wolbachia have revealed unexpected levels of genomic flux and are challenging previously held views about the clonality of obligate intracellular bacteria. We also discuss the roles that this phage might play in the Wolbachia-arthropod symbiosis, and infer how this research can be translated to combating human diseases vectored by arthropods. We expect that this temperate phage will be a preeminent model system to understand phage genetics, evolution, and ecology in obligate intracellular bacteria. In this sense, phage WO might be likened to phage λ of the endosymbiont world. PMID:20083406

  2. Wolbachia: A biological control strategy against arboviral diseases.

    PubMed

    Mohanty, Ipsita; Rath, Animesha; Mahapatra, Namita; Hazra, Rupenangshu K

    2016-01-01

    Vector-borne diseases particularly those transmitted by mosquitoes like Dengue are among the leading causes of mortality and morbidity in human population. There are no effective vaccines or treatment against dengue fever till date and the control methods are limited. So, new approaches are urgently in need to reverse these trends. Vector control is currently the primary intervention tool. Strategies that reduce or block pathogen transmission by mosquitoes have been proposed as a means of augmenting current control measures to reduce the growing burden of vector-borne diseases. Wolbachia an endosymbiont of arthropod vectors is being explored as a novel ecofriendly control strategy. Studies in Drosophila have shown that Wolbachia can confer resistance to diverse RNA viruses and protect flies from virus-induced mortality. This review was focused on biology of the Wolbachia and its implication as a control measure for arboviral diseases mainly Dengue and Chikungunya.

  3. Wolbachia and the biological control of mosquito-borne disease.

    PubMed

    Iturbe-Ormaetxe, Iñaki; Walker, Thomas; O' Neill, Scott L

    2011-06-01

    Mosquito-borne diseases such as malaria, dengue fever and filariasis cause an enormous health burden to people living in tropical and subtropical regions of the world. Despite years of intense effort to control them, many of these diseases are increasing in prevalence, geographical distribution and severity, and options to control them are limited. The transinfection of mosquitos with the maternally inherited, endosymbiotic bacteria Wolbachia is a promising new biocontrol approach. Fruit fly Wolbachia strains can invade and sustain themselves in mosquito populations, reduce adult lifespan, affect mosquito reproduction and interfere with pathogen replication. Wolbachia-infected Aedes aegypti mosquitoes have been released in areas of Australia in which outbreaks of dengue fever occur, as a prelude to the application of this technology in dengue-endemic areas of south-east Asia.

  4. Modulation of host immunity and reproduction by horizontally acquired Wolbachia.

    PubMed

    Pigeault, Romain; Braquart-Varnier, Christine; Marcadé, Isabelle; Mappa, Gaëtan; Mottin, Elmina; Sicard, Mathieu

    2014-11-01

    The Wolbachia are symbiotic bacteria vertically transmitted from one host generation to another. However, a growing amount of data shows that horizontal transfers of Wolbachia also frequently occur within and between host species. The consequences of the arrival of new symbionts on host physiology can be studied by their experimental introduction in asymbiotic hosts. After experimental transfers of the eight major isopod Wolbachia strains in the isopod Porcellio dilatatus only two of them (wCon and wDil) were found to (1) have no pathogenic effect on the host and (2) be able to pass vertically to the host offspring. In the present work, we studied the influence of these two strains, able to complete an horizontal transfer, on immunity and reproduction of P. dilatatus at two stages of the transfer: (1) in recipient hosts that encounter the symbionts: to test the influence of symbiont when acquired during host life and (2) in vertically infected offspring: to test the influence of a symbiotic interaction occurring all lifelong. The impact of Wolbachia varied depending on the stage: there were clearer effects in vertically infected individuals than in those that acquired the symbionts during their lives. Moreover, the two Wolbachia strains showed contrasted effects: the strain wCon tended to reduce the reproductive investment but to maintain or increase immune parameters whilst wDil had positive effects on reproductive investment but decreased the investment in some immune parameters. These results suggest that horizontally acquisition of Wolbachia can influence the balance between host immune and reproductive traits. Copyright © 2014. Published by Elsevier Ltd.

  5. "Good Passengers and Not Good Passengers:" Adolescent Drivers' Perceptions About Inattention and Peer Passengers.

    PubMed

    McDonald, Catherine C; Sommers, Marilyn S

    The purpose of this qualitative focus group elicitation research study was to explore teen driver perceptions of peer passengers and driver inattention. We utilized focus groups for data collection and content analysis to analyze the data, both of which were guided by the theory of planned behavior. We conducted 7 focus groups with 30 teens, ages 16-18, licensed for ≤1year to examine attitudes, perceived behavioral control, and norms related to driving inattention and peer passengers. The sample was 50% male, mean age 17.39 (SD 0.52) with mean length of licensure 173.7days (SD 109.2). Three themes emerged: 1) "Good and not good" passengers; 2) Passengers and technology as harmful and helpful; and 3) The driver is in charge. While passengers can be a source of distraction, our participants also identified passenger behaviors that reduced risk, such as assistance with technology and guidance for directions. An understanding of teens' perceptions of peer passengers can contribute to the development of effective interventions targeting teen driver inattention. Nurses are well-positioned to contribute to these teen crash prevention efforts. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Comparison of Stable and Transient Wolbachia Infection Models in Aedes aegypti to Block Dengue and West Nile Viruses

    PubMed Central

    Joubert, Dirk Albert; O’Neill, Scott L.

    2017-01-01

    Pathogen replication and transmission in Wolbachia infected insects are currently studied using three Wolbachia infection systems: naturally infected Wolbachia hosts, hosts transinfected with Wolbachia (stably maintained and inherited infections) and hosts transiently infected with Wolbachia. All three systems have been used to test the effect of Wolbachia on mosquito transmitted pathogens such as dengue virus (DENV), West Nile virus (WNV) and Plasmodium. From these studies it is becoming increasingly clear that the interaction between a particular pathogen and Wolbachia is heavily influenced by the host-Wolbachia interaction and the model of infection. In particular, there is some evidence that under very specific conditions, Wolbachia can enhance pathogen infection in some hosts. In this study, we compared the effect of Wolbachia in two infection models (stable transinfected and transiently infected) on the replication, infection- and transmission rates of two flaviviruses, DENV and WNV (Kunjin strain). Our results indicate that Wolbachia had similar blocking effects in both stable and transient models of infection, however, the magnitude of the blocking effect was significantly lower in mosquitoes transiently infected with Wolbachia. More importantly, no evidence was found for any enhancement of either DENV or WNV (Kunjin strain) infection in Ae. aegypti infected with Wolbachia, supporting a role for Wolbachia as an effective and safe means for restricting transmission of these viruses. PMID:28052065

  7. Comparison of Stable and Transient Wolbachia Infection Models in Aedes aegypti to Block Dengue and West Nile Viruses.

    PubMed

    Joubert, Dirk Albert; O'Neill, Scott L

    2017-01-01

    Pathogen replication and transmission in Wolbachia infected insects are currently studied using three Wolbachia infection systems: naturally infected Wolbachia hosts, hosts transinfected with Wolbachia (stably maintained and inherited infections) and hosts transiently infected with Wolbachia. All three systems have been used to test the effect of Wolbachia on mosquito transmitted pathogens such as dengue virus (DENV), West Nile virus (WNV) and Plasmodium. From these studies it is becoming increasingly clear that the interaction between a particular pathogen and Wolbachia is heavily influenced by the host-Wolbachia interaction and the model of infection. In particular, there is some evidence that under very specific conditions, Wolbachia can enhance pathogen infection in some hosts. In this study, we compared the effect of Wolbachia in two infection models (stable transinfected and transiently infected) on the replication, infection- and transmission rates of two flaviviruses, DENV and WNV (Kunjin strain). Our results indicate that Wolbachia had similar blocking effects in both stable and transient models of infection, however, the magnitude of the blocking effect was significantly lower in mosquitoes transiently infected with Wolbachia. More importantly, no evidence was found for any enhancement of either DENV or WNV (Kunjin strain) infection in Ae. aegypti infected with Wolbachia, supporting a role for Wolbachia as an effective and safe means for restricting transmission of these viruses.

  8. A data mining approach to investigate the factors influencing the crash severity of motorcycle pillion passengers.

    PubMed

    Tavakoli Kashani, Ali; Rabieyan, Rahim; Besharati, Mohammad Mehdi

    2014-12-01

    Motorcycle passengers comprise a considerable proportion of traffic crash victims. During a 5 year period (2006-2010) in Iran, an average of 3.4 pillion passengers are killed daily due to motorcycle crashes. This study investigated the main factors influencing crash severity of this group of road users. The Classification and Regression Trees (CART) method was employed to analyze the injury severity of pillion passengers in Iran over a 4 y ear period (2009-2012). The predictive accuracy of the model built with a total of 16 variables was 74%, which showed a considerable improvement compared to previous studies. The results indicate that area type, land use, and injured part of the body (head, neck, etc.) are the most influential factors affecting the fatality of motorcycle passengers. Results also show that helmet usage could reduce the fatality risk among motorcycle passengers by 28%. The findings of this study might help develop more targeted countermeasures to reduce the death rate of motorcycle pillion passengers. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Passage of Wolbachia pipientis through mutant drosophila melanogaster induces phenotypic and genomic changes.

    PubMed

    Newton, Irene L G; Sheehan, Kathy B

    2015-02-01

    Wolbachia pipientis is a nearly ubiquitous, maternally transmitted bacterium that infects the germ line of insect hosts. Estimates are that Wolbachia infects 40 to 60% of insect species on the planet, making it one of the most prevalent infections on Earth. However, we know surprisingly little about the molecular mechanisms used by Wolbachia to infect its hosts. We passaged Wolbachia through normally restrictive Drosophila melanogaster hosts, bottlenecking Wolbachia through stochastic segregation while simultaneously selecting for mutants that could recolonize these previously restrictive hosts. Here, we show that Wolbachia alters its behavior when passaged through heterozygous mutant flies. After only three generations, Wolbachia was able to colonize the previously restrictive hosts at control titers. Additionally, the Wolbachia organisms passaged through heterozygous mutant D. melanogaster alter their pattern of tissue-specific Wsp protein production, suggesting a behavioral response to the host genotype. Using whole-genome resequencing, we identified the mutations accumulated by these lineages of Wolbachia and confirmed the existence and persistence of the mutations through clone library Sanger sequencing. Our results suggest that Wolbachia can quickly adapt to new host contexts, with genomic mutants arising after only two generations.

  10. Transinfection: a method to investigate Wolbachia-host interactions and control arthropod-borne disease.

    PubMed

    Hughes, G L; Rasgon, J L

    2014-04-01

    The bacterial endosymbiont Wolbachia manipulates arthropod host biology in numerous ways, including sex ratio distortion and differential offspring survival. These bacteria infect a vast array of arthropods, some of which pose serious agricultural and human health threats. Wolbachia-mediated phenotypes such as cytoplasmic incompatibility and/or pathogen interference can be used for vector and disease control; however, many medically important vectors and important agricultural species are uninfected or are infected with strains of Wolbachia that do not elicit phenotypes desirable for disease or pest control. The ability to transfer strains of Wolbachia into new hosts (transinfection) can create novel Wolbachia-host associations. Transinfection has two primary benefits. First, Wolbachia-host interactions can be examined to tease apart the influence of the host and bacteria on phenotypes. Second, desirable phenotypes induced by Wolbachia in a particular insect can be transferred to another recipient host. This can allow the manipulation of insect populations that transmit pathogens or detrimentally affect agriculture. As such, transinfection is a valuable tool to explore Wolbachia biology and control arthropod-borne disease. The present review summarizes what is currently known about Wolbachia transinfection methods and applications. We also provide a comprehensive list of published successful and unsuccessful Wolbachia transinfection attempts.

  11. Transinfection: a method to investigate Wolbachia-host interactions and control arthropod-borne disease

    PubMed Central

    Hughes, Grant L.; Rasgon, Jason L.

    2014-01-01

    The bacterial endosymbiont Wolbachia manipulates arthropod host biology in numerous ways including sex ratio distortion and differential offspring survival. These bacteria infect a vast array of arthropods, some of which pose serious agricultural and human health threats. Wolbachia-mediated phenotypes such as cytoplasmic incompatibility and/or pathogen interference can be utilized for vector and disease control. However, many medically important vectors and important agricultural species are uninfected or are infected with strains of Wolbachia that do not elicit phenotypes desirable for disease or pest control. The ability to transfer strains of Wolbachia into new hosts (transinfection) can create novel Wolbachia-host associations. Transinfection has two primary benefits. First, Wolbachia-host interactions can be examined to tease apart the influence of the host and bacteria on phenotypes. Secondly, desirable phenotypes induced by Wolbachia in a particular insect can be transferred to another recipient host. This can allow for manipulation of insect populations that transmit pathogens or detrimentally affect agriculture. As such, transinfection is a valuable tool to explore Wolbachia biology and control arthropod-borne disease. This review summarizes what is currently known about Wolbachia transinfection methods and applications. We also provide a comprehensive list of published successful and unsuccessful Wolbachia transinfection attempts. PMID:24329998

  12. Comparative genomics provides a timeframe for Wolbachia evolution and exposes a recent biotin synthesis operon transfer.

    PubMed

    Gerth, Michael; Bleidorn, Christoph

    2016-12-22

    The genus Wolbachia (Alphaproteobacteria) comprises the most abundant inherited intracellular bacteria(1). Despite their relevance as manipulators of human pathogen transmission(2) and arthropod reproduction(3), many aspects of their evolutionary history are not well understood(4). In arthropods, Wolbachia infections are typically transient on evolutionary timescales(5,6) and co-divergence between hosts and Wolbachia is supposedly rare. Consequently, much of our knowledge of Wolbachia genome evolution derives from very recently diverged strains, and a timescale for Wolbachia is lacking. Here, we investigated the genomes of four Wolbachia strains that have persisted within and co-diverged with their host lineage for ∼2 million years. Although the genomes showed very little evolutionary change on a nucleotide level, we found evidence for a recent lateral transfer of a complete biotin synthesis operon that has the potential to transform Wolbachia-host relationships(7). Furthermore, this evolutionary snapshot enabled us to calibrate the divergence times of the supergroup A and B Wolbachia lineages using genome-wide data sets and relaxed molecular clock models. We estimated the origin of Wolbachia supergroups A and B to be ∼200 million years ago (Ma), which is considerably older than previously appreciated. This age coincides with the diversification of many insect lineages(8) that represent most of Wolbachia's host spectrum.

  13. Diversity and evolution of the Wolbachia endosymbionts of Bemisia (Hemiptera: Aleyrodidae) whiteflies

    PubMed Central

    Bing, Xiao-Li; Xia, Wen-Qiang; Gui, Jia-Dong; Yan, Gen-Hong; Wang, Xiao-Wei; Liu, Shu-Sheng

    2014-01-01

    Wolbachia is the most prevalent symbiont described in arthropods to date. Wolbachia can manipulate host reproduction, provide nutrition to insect hosts and protect insect hosts from pathogenic viruses. So far, 13 supergroups of Wolbachia have been identified. The whitefly Bemisia tabaci is a complex containing more than 28 morphologically indistinguishable cryptic species. Some cryptic species of this complex are invasive. In this study, we report a comprehensive survey of Wolbachia in B. tabaci and its relative B. afer from 1658 insects representing 54 populations across 13 provinces of China and one state of Australia. Based on the results of PCR or sequencing of the 16S rRNA gene, the overall rates of Wolbachia infection were 79.6% and 0.96% in the indigenous and invasive Bemisia whiteflies, respectively. We detected a new Wolbachia supergroup by sequencing five molecular marker genes including 16S rRNA, groEL, gltA, hcpA, and fbpA genes. Data showed that many protein-coding genes have limitations in detecting and classifying newly identified Wolbachia supergroups and thus raise a challenge to the known Wolbachia MLST standard analysis system. Besides, the other Wolbachia strains detected from whiteflies were clustered into supergroup B. Phylogenetic trees of whitefly mitochondrial cytochrome oxidase subunit I and Wolbachia multiple sequencing typing genes were not congruent. In addition, Wolbachia was also detected outside the special bacteriocytes in two cryptic species by fluorescence in situ hybridization, indicating the horizontal transmission of Wolbachia. Our results indicate that members of Wolbachia are far from well explored. PMID:25077022

  14. Tissue and Stage-Specific Distribution of Wolbachia in Brugia malayi

    PubMed Central

    Fischer, Kerstin; Beatty, Wandy L.; Jiang, Daojun; Weil, Gary J.; Fischer, Peter U.

    2011-01-01

    Background Most filarial parasite species contain Wolbachia, obligatory bacterial endosymbionts that are crucial for filarial development and reproduction. They are targets for alternative chemotherapy, but their role in the biology of filarial nematodes is not well understood. Light microscopy provides important information on morphology, localization and potential function of these bacteria. Surprisingly, immunohistology and in situ hybridization techniques have not been widely used to monitor Wolbachia distribution during the filarial life cycle. Methods/Principal Findings A monoclonal antibody directed against Wolbachia surface protein and in situ hybridization targeting Wolbachia 16S rRNA were used to monitor Wolbachia during the life cycle of B. malayi. In microfilariae and vector stage larvae only a few cells contain Wolbachia. In contrast, large numbers of Wolbachia were detected in the lateral chords of L4 larvae, but no endobacteria were detected in the genital primordium. In young adult worms (5 weeks p.i.), a massive expansion of Wolbachia was observed in the lateral chords adjacent to ovaries or testis, but no endobacteria were detected in the growth zone of the ovaries, uterus, the growth zone of the testis or the vas deferens. Confocal laser scanning and transmission electron microscopy showed that numerous Wolbachia are aligned towards the developing ovaries and single endobacteria were detected in the germline. In inseminated females (8 weeks p.i.) Wolbachia were observed in the ovaries, embryos and in decreasing numbers in the lateral chords. In young males Wolbachia were found in distinct zones of the testis and in large numbers in the lateral chords in the vicinity of testicular tissue but never in mature spermatids or spermatozoa. Conclusions Immunohistology and in situ hybridization show distinct tissue and stage specific distribution patterns for Wolbachia in B. malayi. Extensive multiplication of Wolbachia occurs in the lateral chords of L4

  15. A Study of the Educationally Influential Physician.

    ERIC Educational Resources Information Center

    Kaufman, David M.; Ryan, Kurt; Hodder, Ian

    1999-01-01

    A survey of 172 family doctors found that they approached educationally influential (EI) physicians they knew through their hospitals; only 20% used e-mail and 40% the Internet for medical information; EI physicians helped extend their knowledge and validate innovations found in the literature; and health care reform was negatively affecting…

  16. Differentially expressed profiles in the larval testes of Wolbachia infected and uninfected Drosophila

    PubMed Central

    2011-01-01

    Background Wolbachia are endosymbiotic bacteria that are frequently found in arthropods and nematodes. These maternally inherited bacteria manipulate host reproduction by several mechanisms including cytoplasmic incompatibility (CI). CI is the most common phenotype induced by Wolbachia and results in the developmental arrest of embryos derived from crosses between Wolbachia-infected males and uninfected females. Although the molecular mechanisms of CI are currently unknown, several studies suggest that host sperm is modified by Wolbachia during spermatogenesis. Results We compared the gene expression of Drosophila melanogaster larval testes with and without the wMel strain of Wolbachia to identify candidate genes that could be involved in the interaction between Wolbachia and the insect host. Microarray, quantitative RT-PCR and in situ hybridization analyses were carried out on D. melanogaster larval testes to determine the effect of Wolbachia infection on host gene expression. A total of 296 genes were identified by microarray analysis to have at least a 1.5 fold change [q-value < 5%] in expression. When comparing Wolbachia-infected flies to uninfected flies, 167 genes were up-regulated and 129 genes down-regulated. Differential expression of genes related to metabolism, immunity, reproduction and other functions were observed. Quantitative RT-PCR (qRT-PCR) confirmed 12 genes are differentially expressed in the testes of the 3rd instar larvae of Wolbachia-infected and uninfected flies. In situ hybridization demonstrated that Wolbachia infection changes the expression of several genes putatively associated with spermatogenesis including JH induced protein-26 and Mst84Db, or involved in immune (kenny) or metabolism (CG4988-RA). Conclusions Wolbachia change the gene expression of 296 genes in the larval testes of D. melanogaster including genes related to metabolism, immunity and reproduction. Interestingly, most of the genes putatively involved in immunity were up

  17. Interspecific transfer of Wolbachia between two lepidopteran insects expressing cytoplasmic incompatibility: a Wolbachia variant naturally infecting Cadra cautella causes male killing in Ephestia kuehniella.

    PubMed Central

    Sasaki, Tetsuhiko; Kubo, Takeo; Ishikawa, Hajime

    2002-01-01

    Wolbachia is known as the causative agent of various reproductive alterations in arthropods. The almond moth Cadra cautella is doubly infected with A- and B-group Wolbachia and expresses complete cytoplasmic incompatibility (CI). The Mediterranean flour moth Ephestia kuehniella carries A-group Wolbachia and expresses partial CI. In the present study, the Wolbachia in C. cautella was transferred to E. kuehniella from which the original Wolbachia had been removed. We obtained transfected lines of three different infection states: single infection with A, single infection with B, and double infection with A and B. The doubly transfected lines and those transfected with only A produced exclusively female progeny. Two lines of evidence suggested that the sex ratio distortion was due to male killing. First, reduced egg hatch rate was observed. Second, removal of the Wolbachia from the transfected lines resulted in the recovery of a normal sex ratio of approximately 1:1. The occurrence of male killing following transfection showed that host factors influence the determination of the reproductive phenotype caused by Wolbachia. The transfected E. kuehniella males carrying exclusively B-group Wolbachia expressed partial incompatibility when crossed with the uninfected females. In addition, the transfected lines were bidirectionally incompatible with the naturally infected strain, which was the first demonstration of bidirectional CI in a lepidopteran. PMID:12454075

  18. Wolbachia and the insect immune system: what reactive oxygen species can tell us about the mechanisms of Wolbachia-host interactions.

    PubMed

    Zug, Roman; Hammerstein, Peter

    2015-01-01

    Wolbachia are intracellular bacteria that infect a vast range of arthropod species, making them one of the most prevalent endosymbionts in the world. Wolbachia's stunning evolutionary success is mostly due to their reproductive parasitism but also to mutualistic effects such as increased host fecundity or protection against pathogens. However, the mechanisms underlying Wolbachia phenotypes, both parasitic and mutualistic, are only poorly understood. Moreover, it is unclear how the insect immune system is involved in these phenotypes and why it is not more successful in eliminating the bacteria. Here we argue that reactive oxygen species (ROS) are likely to be key in elucidating these issues. ROS are essential players in the insect immune system, and Wolbachia infection can affect ROS levels in the host. Based on recent findings, we elaborate a hypothesis that considers the different effects of Wolbachia on the oxidative environment in novel vs. native hosts. We propose that newly introduced Wolbachia trigger an immune response and cause oxidative stress, whereas in coevolved symbioses, infection is not associated with oxidative stress, but rather with restored redox homeostasis. Redox homeostasis can be restored in different ways, depending on whether Wolbachia or the host is in charge. This hypothesis offers a mechanistic explanation for several of the observed Wolbachia phenotypes.

  19. The Wolbachia endosymbiont as an anti-filarial nematode target

    PubMed Central

    Taylor, Mark J.; Foster, Jeremy M.

    2010-01-01

    Human disease caused by parasitic filarial nematodes is a major cause of global morbidity. The parasites are transmitted by arthropod intermediate hosts and are responsible for lymphatic filariasis (elephantiasis) or onchocerciasis (river blindness). Within these filarial parasites are intracellular alpha-proteobacteria, Wolbachia, that were first observed almost 30 years ago. The obligate endosymbiont has been recognized as a target for anti-filarial nematode chemotherapy as evidenced by the loss of worm fertility and viability upon antibiotic treatment in an extensive series of human trials. While current treatments with doxycycline and rifampicin are not practical for widespread use due to the length of required treatments and contraindications, anti-Wolbachia targeting nevertheless appears a promising alternative for filariasis control in situations where current programmatic strategies fail or are unable to be delivered and it provides a superior efficacy for individual therapy. The mechanisms that underlie the symbiotic relationship between Wolbachia and its nematode hosts remain elusive. Comparative genomics, bioinfomatic and experimental analyses have identified a number of potential interactions, which may be drug targets. One candidate is de novo heme biosynthesis, due to its absence in the genome sequence of the host nematode, Brugia malayi, but presence in Wolbachia and its potential roles in worm biology. We describe this and several additional candidate targets, as well as our approaches for understanding the nature of the host-symbiont relationship. PMID:20730111

  20. Assessing the epidemiological effect of wolbachia for dengue control.

    PubMed

    Lambrechts, Louis; Ferguson, Neil M; Harris, Eva; Holmes, Edward C; McGraw, Elizabeth A; O'Neill, Scott L; Ooi, Eng E; Ritchie, Scott A; Ryan, Peter A; Scott, Thomas W; Simmons, Cameron P; Weaver, Scott C

    2015-07-01

    Dengue viruses cause more human morbidity and mortality than any other arthropod-borne virus. Dengue prevention relies mainly on vector control; however, the failure of traditional methods has promoted the development of novel entomological approaches. Although use of the intracellular bacterium wolbachia to control mosquito populations was proposed 50 years ago, only in the past decade has its use as a potential agent of dengue control gained substantial interest. Here, we review evidence that supports a practical approach for dengue reduction through field release of wolbachia-infected mosquitoes and discuss the additional studies that have to be done before the strategy can be validated and implemented. A crucial next step is to assess the efficacy of wolbachia in reducing dengue virus transmission. We argue that a cluster randomised trial is at this time premature because choice of wolbachia strain for release and deployment strategies are still being optimised. We therefore present a pragmatic approach to acquiring preliminary evidence of efficacy through various complementary methods including a prospective cohort study, a geographical cluster investigation, virus phylogenetic analysis, virus surveillance in mosquitoes, and vector competence assays. This multipronged approach could provide valuable intermediate evidence of efficacy to justify a future cluster randomised trial.

  1. Inhibition of Zika virus by Wolbachia in Aedes aegypti

    PubMed Central

    Caragata, Eric Pearce; Dutra, Heverton Leandro Carneiro; Moreira, Luciano Andrade

    2016-01-01

    Through association with cases of microcephaly in 2015, Zika virus (ZIKV) has transitioned from a relatively unknown mosquito-transmitted pathogen to a global health emergency, emphasizing the need to improve existing mosquito control programs to prevent future disease outbreaks. The response to Zika must involve a paradigm shift from traditional to novel methods of mosquito control, and according to the World Health Organization should incorporate the release of mosquitoes infected with the bacterial endosymbiont Wolbachia pipientis. In our recent paper [Dutra, HLC et al., Cell Host & Microbe 2016] we investigated the potential of Wolbachia infections in Aedes aegypti to restrict infection and transmission of Zika virus recently isolated in Brazil. Wolbachia is now well known for its ability to block or reduce infection with a variety of pathogens in different mosquito species including the dengue (DENV), yellow fever, and chikungunya viruses, and malaria-causing Plasmodium, and consequently has great potential to control mosquito-transmitted diseases across the globe. Our results demonstrated that the wMel Wolbachia strain in Brazilian Ae. aegypti is a strong inhibitor of ZIKV infection, and furthermore appears to prevent transmission of infectious viral particles in mosquito saliva, which highlights the bacterium’s suitability for more widespread use in Zika control. PMID:28357366

  2. Effects of Wolbachia on fitness of Culex quinquefasciatus (Diptera; Culicidae).

    PubMed

    Almeida, Fábio de; Moura, Alexandre S; Cardoso, André F; Winter, Carlos E; Bijovsky, A Tania; Suesdek, Lincoln

    2011-12-01

    Wolbachia are α-proteobacteria that were first reported in Culex pipiens mosquitoes early in the twentieth century. Since then, the effect of Wolbachia on their host's reproduction has drawn attention and has been increasingly investigated. Given the extreme complexity of this interaction, new study cases are welcomed to enhance its understanding. The present work addressed the influence of Wolbachia on Cx. quinquefasciatus, the cosmopolitan member of the Cx. pipiens complex. Samples of a Cx. quinquefasciatus colony (wPip(+)) originated from individuals naturally infected by Wolbachiapipientis B strain, were cured with tetracycline, yielding a Wolbachia-free colony (wPip(-)). Both the presence of bacteria and the efficiency of bacterial elimination were checked by PCR of the wsp gene. Total reproductive unidirectional incompatibility occurred when wPip(-) females were crossed with wPip(+) males, whereas the other three types of reciprocal crosses were viable. Reproductive aspects were also comparatively evaluated between colonies. Concerning oviposition time during the first gonotrophic cycle, wPip(+) females developed and laid eggs earlier than did wPip(-) females. Reproductive fitness was higher among wPip(-) than wPip(+) females regarding the following parameters: fertility: egg rafts/fed females; fecundity: eggs/raft, and viability: larvae/eggs. Conversely, longevity of wPip(-) females was lower. Summarising, although the infected mosquitoes have the advantage of a higher longevity, they have lower reproductive fitness. Our results are partly distinct from all other reports on Aedes and Culex mosquitoes previously published.

  3. Wolbachia strains for disease control: ecological and evolutionary considerations

    PubMed Central

    Hoffmann, Ary A; Ross, Perran A; Rašić, Gordana

    2015-01-01

    Wolbachia are endosymbionts found in many insects with the potential to suppress vectorborne diseases, particularly through interfering with pathogen transmission. Wolbachia strains are highly variable in their effects on hosts, raising the issue of which attributes should be selected to ensure that the best strains are developed for disease control. This depends on their ability to suppress viral transmission, invade host populations, persist without loss of viral suppression and not interfere with other control strategies. The potential to achieve these objectives is likely to involve evolutionary constraints; viral suppression may be limited by the ability of infections to spread due to deleterious host fitness effects. However, there are exceptions to these patterns in both natural infections and in novel associations generated following interspecific transfer, suggesting that pathogen blockage, deleterious fitness effects and changes to reproductive biology might be at least partly decoupled to achieve ideal infection attributes. The stability of introduced Wolbachia and its effects on viral transmission remain unclear, but rapid evolutionary changes seem unlikely. Although deliberate transfers of Wolbachia across species remain particularly challenging, the availability of strains with desirable attributes should be expanded, taking advantage of the diversity available across thousands of strains in natural populations. PMID:26366194

  4. Wolbachia infection decreased the resistance of Drosophila to lead.

    PubMed

    Wang, Ling; Zhou, Chun; He, Zhen; Wang, Zheng-Guang; Wang, Jia-Lin; Wang, Yu-Feng

    2012-01-01

    The heavy metal lead has been shown to be associated with a genotoxic risk. Drosophila melanogaster is a model organism commonly utilized in genetic toxicology testing. The endosymbionts--Wolbachia are now very common in both wild populations and laboratory stocks of Drosophila. Wolbachia may induce resistance to pathogenic viruses, filarial nematodes and Plasmodium in fruit fly and mosquito hosts. However the effect of Wolbachia infection on the resistance of their hosts to heavy metal is unknown. Manipulating the lead content in the diet of Drosophila melanogaster, we found that lead consumption had no different effects on developmental time between Wolbachia-infected (Dmel wMel) and -uninfected (Dmel T) flies. While in Pb-contaminated medium, significantly reduced amount of pupae and adults of Dmel wMel were emerged, and Dmel wMel adults had significantly shorter longevity than that of Dmel T flies. Lead infusion in diet resulted in significantly decreased superoxide dismutase (SOD) activity in Dmel T flies (P<0.05), but not in Dmel wMel flies. Correspondingly, lead cultures induced a 10.8 fold increase in malonaldehyde (MDA) contents in Dmel T larvae (P<0.05). While in Dmel wMel larvae, it resulted in only a 1.3 fold increase. By quantitative RT-PCR, we showed that lead infused medium caused significantly increased expression level of relish and CecA2 genes in Dmel T flies (P<0.01). Lead cultures did not change dramatically the expression of these genes in Dmel wMel flies. These results suggest that Wolbachia infection decreased the resistance of Drosophila to lead likely by limiting the production of peroxides resulted from lead, thus being unable to activate the immunological pathway in the host to prevent them from lead damage. This represents a novel Wolbachia-host interaction and provides information that researchers working on Drosophila toxicology should take in consideration the presence of Wolbachia in the stocks they are analyzing.

  5. Social parasitism in fire ants (Solenopsis spp.): a potential mechanism for interspecies transfer of Wolbachia.

    PubMed

    Dedeine, Franck; Ahrens, Michael; Calcaterra, Luis; Shoemaker, D Dewayne

    2005-04-01

    One possible mechanism for interspecific transfer of Wolbachia is through the intimate contact between parasites and their hosts. We surveyed 10 species of fly parasitoids (Pseudacteon spp.) and one inquiline social parasite, Solenopsis daguerrei, for the presence and sequence identity (wsp gene) of Wolbachia. Two Wolbachia variants infecting S. daguerrei were identical to known variants infecting the two common ant host species, Solenopsis invicta and Solenopsis richteri, suggesting possible transfers of Wolbachia between this parasite and their hosts have occurred. Our data also revealed an unexpectedly high diversity of Wolbachia variants within S. daguerrei: up to eight variants were found within each individual, which, to our knowledge, is the highest reported number of Wolbachia variants infecting a single individual of any host species.

  6. Detection of Wolbachia in Aedes albopictus and Their Effects on Chikungunya Virus

    PubMed Central

    Ahmad, Noor Afizah; Vythilingam, Indra; Lim, Yvonne A. L.; Zabari, Nur Zatil Aqmar M.; Lee, Han Lim

    2017-01-01

    Wolbachia-based vector control strategies have been proposed as a means to augment the currently existing measures for controlling dengue and chikungunya vectors. Prior to utilizing Wolbachia as a novel vector control strategy, it is crucial to understand the Wolbachia–mosquito interactions. In this study, field surveys were conducted to screen for the infection status of Wolbachia in field-collected Aedes albopictus. The effects of Wolbachia in its native host toward the replication and dissemination of chikungunya virus (CHIKV) was also studied. The prevalence of Wolbachia-infected field-collected Ae. albopictus was estimated to be 98.6% (N = 142) for females and 95.1% (N = 102) for males in the population studied. The Ae. albopictus were naturally infected with both wAlbA and wAlbB strains. We also found that the native Wolbachia has no impact on CHIKV infection and minimal effect on CHIKV dissemination to secondary organs. PMID:27920393

  7. Ultrastructural and molecular identification of a Wolbachia endosymbiont in a spider, Nephila clavata.

    PubMed

    Oh, H W; Kim, M G; Shin, S W; Bae, K S; Ahn, Y J; Park, H Y

    2000-10-01

    Wolbachia-like bacteria were observed in the egg cells of golden orb-weaving spider, Nephila clavata, by means of transmission electron microscopy. The bacteria exhibited the typical morphology of Wolbachia, including three enveloping membranes. Based on the amplification and sequencing of partial 16S rDNA and ftsZ gene, the bacteria were identified as Wolbachia, intracellular, transovarially inherited alpha-proteobacteria in invertebrates. Phylogenetic analysis based on 16S rDNA and ftsZ gene sequences invariably indicated that the intracellular bacteria from N. clavata belonged to group A Wolbachia, which were found only from insects. Clustering of Wolbachia from N. clavata with group A Wolbachia indicates that the bacteria were probably transferred horizontally between insects and the spider.

  8. Pathogenicity of life-shortening Wolbachia in Aedes albopictus after transfer from Drosophila melanogaster.

    PubMed

    Suh, Eunho; Mercer, David R; Fu, Yuqing; Dobson, Stephen L

    2009-12-01

    Maternally inherited Wolbachia bacteria have evolved mechanisms to manipulate the reproduction of their invertebrate hosts, promoting infection spread. A high fitness cost to the host is maladaptive for obligate endosymbionts, and prior studies show rapid selection of new Wolbachia associations toward commensal or mutualistic symbioses. Here, wMelPop Wolbachia is transferred from Drosophila melanogaster into the mosquito Aedes albopictus. Characterization of the resulting strain provides an extreme example of Wolbachia as a pathogen. In addition to reduced longevity and fecundity, abnormally high Wolbachia density is associated with embryonic mortality that masks the typical pattern of cytoplasmic incompatibility. The results are consistent with earlier reports that show unpredictable shifts in the Wolbachia phenotype after interspecific transfer, which can complicate proposed strategies to modify the age structure of medically important vector populations.

  9. Evolutionary origin of insect–Wolbachia nutritional mutualism

    PubMed Central

    Nikoh, Naruo; Hosokawa, Takahiro; Moriyama, Minoru; Oshima, Kenshiro; Hattori, Masahira; Fukatsu, Takema

    2014-01-01

    Obligate insect–bacterium nutritional mutualism is among the most sophisticated forms of symbiosis, wherein the host and the symbiont are integrated into a coherent biological entity and unable to survive without the partnership. Originally, however, such obligate symbiotic bacteria must have been derived from free-living bacteria. How highly specialized obligate mutualisms have arisen from less specialized associations is of interest. Here we address this evolutionary issue by focusing on an exceptional insect–Wolbachia nutritional mutualism. Although Wolbachia endosymbionts are ubiquitously found in diverse insects and generally regarded as facultative/parasitic associates for their insect hosts, a Wolbachia strain associated with the bedbug Cimex lectularius, designated as wCle, was shown to be essential for host’s growth and reproduction via provisioning of B vitamins. We determined the 1,250,060-bp genome of wCle, which was generally similar to the genomes of insect-associated facultative Wolbachia strains, except for the presence of an operon encoding the complete biotin synthetic pathway that was acquired via lateral gene transfer presumably from a coinfecting endosymbiont Cardinium or Rickettsia. Nutritional and physiological experiments, in which wCle-infected and wCle-cured bedbugs of the same genetic background were fed on B-vitamin–manipulated blood meals via an artificial feeding system, demonstrated that wCle certainly synthesizes biotin, and the wCle-provisioned biotin significantly contributes to the host fitness. These findings strongly suggest that acquisition of a single gene cluster consisting of biotin synthesis genes underlies the bedbug–Wolbachia nutritional mutualism, uncovering an evolutionary transition from facultative symbiosis to obligate mutualism facilitated by lateral gene transfer in an endosymbiont lineage. PMID:24982177

  10. Evolutionary origin of insect-Wolbachia nutritional mutualism.

    PubMed

    Nikoh, Naruo; Hosokawa, Takahiro; Moriyama, Minoru; Oshima, Kenshiro; Hattori, Masahira; Fukatsu, Takema

    2014-07-15

    Obligate insect-bacterium nutritional mutualism is among the most sophisticated forms of symbiosis, wherein the host and the symbiont are integrated into a coherent biological entity and unable to survive without the partnership. Originally, however, such obligate symbiotic bacteria must have been derived from free-living bacteria. How highly specialized obligate mutualisms have arisen from less specialized associations is of interest. Here we address this evolutionary issue by focusing on an exceptional insect-Wolbachia nutritional mutualism. Although Wolbachia endosymbionts are ubiquitously found in diverse insects and generally regarded as facultative/parasitic associates for their insect hosts, a Wolbachia strain associated with the bedbug Cimex lectularius, designated as wCle, was shown to be essential for host's growth and reproduction via provisioning of B vitamins. We determined the 1,250,060-bp genome of wCle, which was generally similar to the genomes of insect-associated facultative Wolbachia strains, except for the presence of an operon encoding the complete biotin synthetic pathway that was acquired via lateral gene transfer presumably from a coinfecting endosymbiont Cardinium or Rickettsia. Nutritional and physiological experiments, in which wCle-infected and wCle-cured bedbugs of the same genetic background were fed on B-vitamin-manipulated blood meals via an artificial feeding system, demonstrated that wCle certainly synthesizes biotin, and the wCle-provisioned biotin significantly contributes to the host fitness. These findings strongly suggest that acquisition of a single gene cluster consisting of biotin synthesis genes underlies the bedbug-Wolbachia nutritional mutualism, uncovering an evolutionary transition from facultative symbiosis to obligate mutualism facilitated by lateral gene transfer in an endosymbiont lineage.

  11. Comparative genomics of Wolbachia and the bacterial species concept.

    PubMed

    Ellegaard, Kirsten Maren; Klasson, Lisa; Näslund, Kristina; Bourtzis, Kostas; Andersson, Siv G E

    2013-04-01

    The importance of host-specialization to speciation processes in obligate host-associated bacteria is well known, as is also the ability of recombination to generate cohesion in bacterial populations. However, whether divergent strains of highly recombining intracellular bacteria, such as Wolbachia, can maintain their genetic distinctness when infecting the same host is not known. We first developed a protocol for the genome sequencing of uncultivable endosymbionts. Using this method, we have sequenced the complete genomes of the Wolbachia strains wHa and wNo, which occur as natural double infections in Drosophila simulans populations on the Seychelles and in New Caledonia. Taxonomically, wHa belong to supergroup A and wNo to supergroup B. A comparative genomics study including additional strains supported the supergroup classification scheme and revealed 24 and 33 group-specific genes, putatively involved in host-adaptation processes. Recombination frequencies were high for strains of the same supergroup despite different host-preference patterns, leading to genomic cohesion. The inferred recombination fragments for strains of different supergroups were of short sizes, and the genomes of the co-infecting Wolbachia strains wHa and wNo were not more similar to each other and did not share more genes than other A- and B-group strains that infect different hosts. We conclude that Wolbachia strains of supergroup A and B represent genetically distinct clades, and that strains of different supergroups can co-exist in the same arthropod host without converging into the same species. This suggests that the supergroups are irreversibly separated and that barriers other than host-specialization are able to maintain distinct clades in recombining endosymbiont populations. Acquiring a good knowledge of the barriers to genetic exchange in Wolbachia will advance our understanding of how endosymbiont communities are constructed from vertically and horizontally transmitted genes.

  12. Comparative Genomics of Wolbachia and the Bacterial Species Concept

    PubMed Central

    Näslund, Kristina; Bourtzis, Kostas; Andersson, Siv G. E.

    2013-01-01

    The importance of host-specialization to speciation processes in obligate host-associated bacteria is well known, as is also the ability of recombination to generate cohesion in bacterial populations. However, whether divergent strains of highly recombining intracellular bacteria, such as Wolbachia, can maintain their genetic distinctness when infecting the same host is not known. We first developed a protocol for the genome sequencing of uncultivable endosymbionts. Using this method, we have sequenced the complete genomes of the Wolbachia strains wHa and wNo, which occur as natural double infections in Drosophila simulans populations on the Seychelles and in New Caledonia. Taxonomically, wHa belong to supergroup A and wNo to supergroup B. A comparative genomics study including additional strains supported the supergroup classification scheme and revealed 24 and 33 group-specific genes, putatively involved in host-adaptation processes. Recombination frequencies were high for strains of the same supergroup despite different host-preference patterns, leading to genomic cohesion. The inferred recombination fragments for strains of different supergroups were of short sizes, and the genomes of the co-infecting Wolbachia strains wHa and wNo were not more similar to each other and did not share more genes than other A- and B-group strains that infect different hosts. We conclude that Wolbachia strains of supergroup A and B represent genetically distinct clades, and that strains of different supergroups can co-exist in the same arthropod host without converging into the same species. This suggests that the supergroups are irreversibly separated and that barriers other than host-specialization are able to maintain distinct clades in recombining endosymbiont populations. Acquiring a good knowledge of the barriers to genetic exchange in Wolbachia will advance our understanding of how endosymbiont communities are constructed from vertically and horizontally transmitted genes

  13. Prevailing triple infection with Wolbachia in Callosobruchus chinensis (Coleoptera: Bruchidae).

    PubMed

    Kondo, Natsuko; Ijichi, Nobuyuki; Shimada, Masakazu; Fukatsu, Takema

    2002-02-01

    Prevailing triple infection with three distinct Wolbachia strains was identified in Japanese populations of the adzuki bean beetle, Callosobruchus chinensis. When a polymerase chain reaction (PCR) assay was conducted using universal primers for ftsZ and wsp, Wolbachia was detected in all the individuals examined, 288 males and 334 females from nine Japanese populations. PCR-restriction fragment length polymorphism (RFLP) analysis of cloned wsp gene fragments from single insects revealed that three types of wsp sequences coexist in the insects. Molecular phylogenetic analysis of the wsp sequences unequivocally demonstrated that C. chinensis harbours three phylogenetically distinct Wolbachia, tentatively designated as wBruCon, wBruOri and wBruAus, respectively. Diagnostic PCR analysis using specific primers demonstrated that, of 175 males and 235 females from nine local populations, infection frequencies with wBruCon, wBruOri and wBruAus were 100%, 96.3% and 97.0%, respectively. As for the infection status of individuals, triple infection (93.7%) dominated over double infection (6.1%) and single infection (0.2%). The amounts of wBruCon, wBruOri and wBruAus in field-collected adult insects were analysed by using a quantitative PCR technique in terms of wsp gene copies per individual insect. Irrespective of original populations, wBruCon and wBruOri (107 -108 wsp copies/insect) were consistently greater in amount than wBruAus (106 -107 wsp copies/insect), suggesting that the population sizes of the three Wolbachia strains are controlled, although the mechanism is unknown. Mating experiments suggested that the three Wolbachia cause cytoplasmic incompatibility at different levels of intensity.

  14. Sequences of Wolbachia wsp genes reveal multiple infection of individual northern corn rootworms (Diabrotica barberi) by several Wolbachia strains

    USDA-ARS?s Scientific Manuscript database

    Northern corn rootworm (Diabrotica barberi)(NCR) populations in the USA are infected with at least 4 strains of the endosymbiont, Wolbachia. NCR from eastern Illinois to Pennsylvania appear to harbor at least 4 different strains designated wBar1, wBar3, wBar4, and wBar5. NCR from central Illinois ...

  15. Wolbachia Infections in the Cimicidae: Museum Specimens as an Untapped Resource for Endosymbiont Surveys

    PubMed Central

    Sakamoto, Joyce M.; Feinstein, Julie; Rasgon, Jason L.

    2006-01-01

    Wolbachia spp. are obligate maternally inherited endosymbiotic bacteria that infect diverse arthropods and filarial nematodes. Previous microscopic and molecular studies have identified Wolbachia in several bed bug species (Cimicidae), but little is known about how widespread Wolbachia infections are among the Cimicidae. Because cimicids of non-medical importance are not commonly collected, we hypothesized that preserved museum specimens could be assayed for Wolbachia infections. For the screening of museum specimens, we designed a set of primers that specifically amplify small diagnostic fragments (130 to 240 bp) of the Wolbachia 16S rRNA gene. Using these and other previously published primers, we screened 39 cimicid species (spanning 16 genera and all 6 recognized subfamilies) and 2 species of the sister family Polyctenidae for Wolbachia infections using museum and wild-caught material. Amplified fragments were sequenced to confirm that our primers were amplifying Wolbachia DNA. We identified 10 infections, 8 of which were previously undescribed. Infections in the F supergroup were common in the subfamily Cimicinae, while infections in the A supergroup were identified in the subfamilies Afrocimicinae and Haematosiphoninae. Even though specimens were degraded, we detected infections in over 23% of cimicid species. Our results indicate that Wolbachia infections may be common among cimicids and that archived museum material is a useful untapped resource for invertebrate endosymbiont surveys. The new screening primers listed in this report will be useful for other researchers conducting Wolbachia surveys with specimens with less-than-optimum DNA quality. PMID:16672453

  16. Bad guys turned nice? A critical assessment of Wolbachia mutualisms in arthropod hosts.

    PubMed

    Zug, Roman; Hammerstein, Peter

    2015-02-01

    Wolbachia are the most abundant bacterial endosymbionts among arthropods. Although maternally inherited, they do not conform to the widespread view that vertical transmission inevitably selects for beneficial symbionts. Instead, Wolbachia are notorious for their reproductive parasitism which, although lowering host fitness, ensures their spread. However, even for reproductive parasites it can pay to enhance host fitness. Indeed, there is a recent upsurge of reports on Wolbachia-associated fitness benefits. Therefore, the question arises how such instances of mutualism are related to the phenotypes of reproductive parasitism. Here, we review the evidence of Wolbachia mutualisms in arthropods, including both facultative and obligate relationships, and critically assess their biological relevance. Although many studies report anti-pathogenic effects of Wolbachia, few actually prove these effects to be relevant to field conditions. We further show that Wolbachia frequently have beneficial and detrimental effects at the same time, and that reproductive manipulations and obligate mutualisms may share common mechanisms. These findings undermine the idea of a clear-cut distinction between Wolbachia mutualism and parasitism. In general, both facultative and obligate mutualisms can have a strong, and sometimes unforeseen, impact on the ecology and evolution of Wolbachia and their arthropod hosts. Acknowledging this mutualistic potential might be the key to a better understanding of some unresolved issues in the study of Wolbachia-host interactions.

  17. Bidirectional cytoplasmic incompatibility caused by Wolbachia in the terrestrial isopod Porcellio dilatatus.

    PubMed

    Sicard, Mathieu; Bouchon, Didier; Ceyrac, Laura; Raimond, Roland; Thierry, Magali; Le Clec'h, Winka; Marcadé, Isabelle; Caubet, Yves; Grève, Pierre

    2014-09-01

    In the terrestrial isopod species Porcellio dilatatus, unidirectional Cytoplasmic Incompatibility (CI) between two morphs (P. d. dilatatus and P. d. petiti) caused by a Wolbachia strain (wPet) infecting the morph P. d. petiti has been previously described by experiments initiated four decades ago. Here, we studied another Wolbachia that has been recently detected in a population of the morph P. d. dilatatus. The MLST markers reveal that this Wolbachia is a new strain called wDil distinct from wPet also belonging to the isopod clade of Wolbachia. Quantifications of both Wolbachia strains in the gonads of the two P. dilatatus morphs revealed that all males exhibit similar Wolbachia titers while the titers in females depend on the Wolbachia strain they host. Crossing experiments showed that both wDil and wPet induced partial unidirectional CI with different intensities. Moreover, these two strains induced bidirectional CI when individuals were both infected with one of the two different Wolbachia strains. This way, we demonstrated that P. dilatatus can be infected by two closely related Wolbachia strains (wDil and wPet), that seem to have different modification-rescue systems.

  18. Experimental evolution reveals habitat-specific fitness dynamics among Wolbachia clades in Drosophila melanogaster.

    PubMed

    Versace, Elisabetta; Nolte, Viola; Pandey, Ram Vinay; Tobler, Ray; Schlötterer, Christian

    2014-02-01

    The diversity and infection dynamics of the endosymbiont Wolbachia can be influenced by many factors, such as transmission rate, cytoplasmic incompatibility, environment, selection and genetic drift. The interplay of these factors in natural populations can result in heterogeneous infection patterns with substantial differences between populations and strains. The causes of these heterogeneities are not yet understood, partly due to the complexity of natural environments. We present experimental evolution as a new approach to study Wolbachia infection dynamics in replicate populations exposed to a controlled environment. A natural Drosophila melanogaster population infected with strains of Wolbachia belonging to different clades evolved in two laboratory environments (hot and cold) for 1.5 years. In both treatments, the rate of Wolbachia infection increased until fixation. In the hot environment, the relative frequency of different Wolbachia clades remained stable over 37 generations. In the cold environment, however, we observed marked changes in the composition of the Wolbachia population: within 15 generations, one Wolbachia clade increased more than 50% in frequency, whereas the other two clades decreased in frequency, resulting in the loss of one clade. The frequency change was highly reproducible not only among replicates, but also when flies that evolved for 42 generations in the hot environment were transferred to the cold environment. These results document how environmental factors can affect the composition of Wolbachia in D. melanogaster. The high reproducibility of the pattern suggests that experimental evolution studies can efficiently determine the functional basis of habitat-specific fitness among Wolbachia strains.

  19. Inter-population variation for Wolbachia induced reproductive incompatibility in the haplodiploid mite Tetranychus urticae.

    PubMed

    Suh, Eunho; Sim, Cheolho; Park, Jung-Joon; Cho, Kijong

    2015-01-01

    Recent studies have revealed diverse patterns of cytoplasmic incompatibility (CI) induced by Wolbachia in the two spotted spider mite (Tetranychus urticae Koch). The mechanism of CI consists of two steps: modification (mod) of sperm of infected males and the rescue (resc) of these chromosomes by Wolbachia in the egg, which results in female embryonic mortality (FM), male development (MD) or no CI. Our study reports that Wolbachia infections were highly prevalent infecting all T. urticae populations from various crops in 14 commercial greenhouses in Korea, with two Wolbachia strains expressing distinctive phenotypic effects on hosts. Analyses for wsp gene sequences obtained from collected mite populations revealed all sequences were categorized into two groups (group W1 and W2) discriminated by three diagnostic nucleotides while all Wolbachia strains belonged to the subgroup Ori in Wolbachia supergroup B. Host plants of each mite population were also generally correlated this grouping. Various mating experiments with two mite populations from each group showed that CI patterns and host plants of the mite populations were completely matched with the grouping; no CI (mod(-)resc(+)) for group W1 and mixed pattern of FM and MD (mod(+)resc(+)) for group W2. No distinct changes in fecundity or sex ratio due to Wolbachia infections were observed in four mite populations regardless of Wolbachia grouping. Our study suggests a potential correlation between phenotypic effect of Wolbachia infection and its genetic diversity associated with host plants in Korean mite populations.

  20. Wolbachia enhance Drosophila stem cell proliferation and target the germline stem cell niche.

    PubMed

    Fast, Eva M; Toomey, Michelle E; Panaram, Kanchana; Desjardins, Danielle; Kolaczyk, Eric D; Frydman, Horacio M

    2011-11-18

    Wolbachia are widespread maternally transmitted intracellular bacteria that infect most insect species and are able to alter the reproduction of innumerous hosts. The cellular bases of these alterations remain largely unknown. Here, we report that Drosophila mauritiana infected with a native Wolbachia wMau strain produces about four times more eggs than the noninfected counterpart. Wolbachia infection leads to an increase in the mitotic activity of germline stem cells (GSCs), as well as a decrease in programmed cell death in the germarium. Our results suggest that up-regulation of GSC division is mediated by a tropism of Wolbachia for the GSC niche, the cellular microenvironment that supports GSCs.

  1. Wolbachia Endobacteria in Natural Populations of Culex pipiens of Iran and Its Phylogenetic Congruence

    PubMed Central

    Karami, Mohsen; Moosa-Kazemi, Seyed Hassan; Oshaghi, Mohammad Ali; Vatandoost, Hasan; Sedaghat, Mohammad Mehdi; Rajabnia, Ramazan; Hosseini, Mostafa; Maleki-Ravasan, Naseh; Yahyapour, Yousef; Ferdosi-Shahandashti, Elaheh

    2016-01-01

    Background: Wolbachia are common intracellular bacteria that infect different groups of arthropods including mosquitoes. These bacteria modify host biology and may induce feminization, parthenogenesis, male killing and cytoplasmic incompatibility (CI). Recently Wolbachia is being nominated as a bio-agent and paratransgenic candidate to control mosquito borne diseases. Methods: Here we report the results of a survey for presence, frequency, and phylogenetic congruence of these endosymbiont bacteria in Culex pipiens populations in Northern, Central, and Southern parts of Iran using nested-PCR amplification of wsp gene. Results: Wolbachia DNA were found in 227 (87.3%) out of 260 wild-caught mosquitoes. The rate of infection in adult females ranged from 61.5% to 100%, while in males were from 80% to 100%. The Blast search and phylogenetic analysis of the wsp gene sequence revealed that the Wolbachia strain from Iranian Cx. pipiens was identical to the Wolbachia strains of supergroup B previously reported in members of the Cx. pipiens complex. They had also identical sequence homology with the Wolbachia strains from a group of distinct arthropods including lepidopteran, wasps, flies, damselfly, thrips, and mites from remote geographical areas of the world. Conclusion: It is suggested that Wolbachia strains horizontally transfer between unrelated host organisms over evolutionary time. Also results of this study indicates that Wolbachia infections were highly prevalent infecting all Cx. pipiens populations throughout the country, however further study needs to define Wolbachia inter-population reproductive incompatibility pattern and its usefulness as a bio-agent control measure. PMID:27308293

  2. Perturbed cholesterol and vesicular trafficking associated with dengue blocking in Wolbachia-infected Aedes aegypti cells.

    PubMed

    Geoghegan, Vincent; Stainton, Kirsty; Rainey, Stephanie M; Ant, Thomas H; Dowle, Adam A; Larson, Tony; Hester, Svenja; Charles, Philip D; Thomas, Benjamin; Sinkins, Steven P

    2017-09-13

    Wolbachia are intracellular maternally inherited bacteria that can spread through insect populations and block virus transmission by mosquitoes, providing an important approach to dengue control. To better understand the mechanisms of virus inhibition, we here perform proteomic quantification of the effects of Wolbachia in Aedes aegypti mosquito cells and midgut. Perturbations are observed in vesicular trafficking, lipid metabolism and in the endoplasmic reticulum that could impact viral entry and replication. Wolbachia-infected cells display a differential cholesterol profile, including elevated levels of esterified cholesterol, that is consistent with perturbed intracellular cholesterol trafficking. Cyclodextrins have been shown to reverse lipid accumulation defects in cells with disrupted cholesterol homeostasis. Treatment of Wolbachia-infected Ae. aegypti cells with 2-hydroxypropyl-β-cyclodextrin restores dengue replication in Wolbachia-carrying cells, suggesting dengue is inhibited in Wolbachia-infected cells by localised cholesterol accumulation. These results demonstrate parallels between the cellular Wolbachia viral inhibition phenotype and lipid storage genetic disorders. Wolbachia infection of mosquitoes can block dengue virus infection and is tested in field trials, but the mechanism of action is unclear. Using proteomics, Geoghegan et al. here identify effects of Wolbachia on cholesterol homeostasis and dengue virus replication in Aedes aegypti.

  3. Invasion of Wolbachia into Anopheles and Other Insect Germlines in an Ex vivo Organ Culture System

    PubMed Central

    Xue, Ping; Rasgon, Jason L.

    2012-01-01

    The common bacterial endosymbiont Wolbachia manipulates its host's reproduction to promote its own maternal transmission, and can interfere with pathogen development in many insects making it an attractive agent for the control of arthropod-borne disease. However, many important species, including Anopheles mosquitoes, are uninfected. Wolbachia can be artificially transferred between insects in the laboratory but this can be a laborious and sometimes fruitless process. We used a simple ex vivo culturing technique to assess the suitability of Wolbachia-host germline associations. Wolbachia infects the dissected germline tissue of multiple insect species when the host tissue and bacteria are cultured together. Ovary and testis infection occurs in a density-dependent manner. Wolbachia strains are more capable of invading the germline of their native or closely related rather than divergent hosts. The ability of Wolbachia to associate with the germline of novel hosts is crucial for the development of stably-transinfected insect lines. Rapid assessment of the suitability of a strain-host combination prior to transinfection may dictate use of a particular Wolbachia strain. Furthermore, the cultured germline tissues of two major Anopheline vectors of Plasmodium parasites are susceptible to Wolbachia infection. This finding further enhances the prospect of using Wolbachia for the biological control of malaria. PMID:22558418

  4. Wolbachia enhances West Nile virus (WNV) infection in the mosquito Culex tarsalis.

    PubMed

    Dodson, Brittany L; Hughes, Grant L; Paul, Oluwatobi; Matacchiero, Amy C; Kramer, Laura D; Rasgon, Jason L

    2014-07-01

    Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain) on infection, dissemination and transmission of West Nile virus (WNV) in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway) was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector-borne disease control program.

  5. Molecular characterization of Wolbachia strains associated with the invasive Asian citrus psyllid Diaphorina citri in Brazil.

    PubMed

    Guidolin, A S; Cônsoli, F L

    2013-02-01

    Wolbachia is a symbiont intensively studied due to its ability to interfere with their host's reproduction, and it has been recently proposed as an alternative tool to control insect pests or vectors of diseases. The Asian citrus psyllid Diaphorina citri is an important pest of citrus since it vectors the bacterium that causes the "Huanglongbing" disease in citrus. The frequency and diversity of Wolbachia associated with D. citri is unknown, limiting the utilization of Wolbachia as an alternative strategy for insect management. Thus, we aimed to determine the natural rate of infection, to characterize the Wolbachia strains associated with this psyllid by "multilocus sequencing typing" (MLST) and wsp analysis, and to verify the association of the symbiont to particular genotypes of the host. Analysis indicated Wolbachia infects 100 % of all specimens tested from all 15 sampled populations. MLST revealed the occurrence of five new sequence types (STs) of Wolbachia, while analysis based on the wsp sequences indicated only four different types of Wolbachia. ST-173 was predominant, while the remaining STs were population specific. Analysis of the host-symbiont relationship did not reveal any particular association of Wolbachia and haplotypes or a decrease in nucleotide diversity of D. citri in populations in which more than one ST was recorded. The consequences of the diversity of STs reported are still unknown, but the fact that Wolbachia infection is fixed and that there is one ST with a broad distribution highlights the use of this symbiont as an alternative strategy to control D. citri.

  6. Wolbachia Utilizes Host Microtubules and Dynein for Anterior Localization in the Drosophila Oocyte

    PubMed Central

    Li, Jennifer M; Cao, Jian; Wieschaus, Eric; Sullivan, William

    2005-01-01

    To investigate the role of the host cytoskeleton in the maternal transmission of the endoparasitic bacteria Wolbachia, we have characterized their distribution in the female germ line of Drosophila melanogaster. In the germarium, Wolbachia are distributed to all germ cells of the cyst, establishing an early infection in the cell destined to become the oocyte. During mid-oogenesis, Wolbachia exhibit a distinct concentration between the anterior cortex and the nucleus in the oocyte, where many bacteria appear to contact the nuclear envelope. Following programmed rearrangement of the microtubule network, Wolbachia dissociate from this anterior position and become dispersed throughout the oocyte. This localization pattern is distinct from mitochondria and all known axis determinants. Manipulation of microtubules and cytoplasmic Dynein and Dynactin, but not Kinesin-1, disrupts anterior bacterial localization in the oocyte. In live egg chambers, Wolbachia exhibit movement in nurse cells but not in the oocyte, suggesting that the bacteria are anchored by host factors. In addition, we identify mid-oogenesis as a period in the life cycle of Wolbachia in which bacterial replication occurs. Total bacterial counts show that Wolbachia increase at a significantly higher rate in the oocyte than in the average nurse cell, and that normal Wolbachia levels in the oocyte depend on microtubules. These findings demonstrate that Wolbachia utilize the host microtubule network and associated proteins for their subcellular localization in the Drosophila oocyte. These interactions may also play a role in bacterial motility and replication, ultimately leading to the bacteria's efficient maternal transmission. PMID:16228015

  7. Invasion of Wolbachia into Anopheles and other insect germlines in an ex vivo organ culture system.

    PubMed

    Hughes, Grant L; Pike, Andrew D; Xue, Ping; Rasgon, Jason L

    2012-01-01

    The common bacterial endosymbiont Wolbachia manipulates its host's reproduction to promote its own maternal transmission, and can interfere with pathogen development in many insects making it an attractive agent for the control of arthropod-borne disease. However, many important species, including Anopheles mosquitoes, are uninfected. Wolbachia can be artificially transferred between insects in the laboratory but this can be a laborious and sometimes fruitless process. We used a simple ex vivo culturing technique to assess the suitability of Wolbachia-host germline associations. Wolbachia infects the dissected germline tissue of multiple insect species when the host tissue and bacteria are cultured together. Ovary and testis infection occurs in a density-dependent manner. Wolbachia strains are more capable of invading the germline of their native or closely related rather than divergent hosts. The ability of Wolbachia to associate with the germline of novel hosts is crucial for the development of stably-transinfected insect lines. Rapid assessment of the suitability of a strain-host combination prior to transinfection may dictate use of a particular Wolbachia strain. Furthermore, the cultured germline tissues of two major Anopheline vectors of Plasmodium parasites are susceptible to Wolbachia infection. This finding further enhances the prospect of using Wolbachia for the biological control of malaria.

  8. Wolbachia endosymbionts in haplodiploid and diploid scolytine beetles (Coleoptera: Curculionidae: Scolytinae).

    PubMed

    Kawasaki, Yuuki; Schuler, Hannes; Stauffer, Christian; Lakatos, Ferenc; Kajimura, Hisashi

    2016-05-19

    Haplodiploidy is a sex determination system in which fertilized diploid eggs develop into females and unfertilized haploid eggs develop into males. The evolutionary explanations for this phenomenon include the possibility that haplodiploidy can be reinforced by infection with endosymbiotic bacteria, such as Wolbachia. The subfamily Scolytinae contains species with haplodiploid and diploid sex determination systems. Thus, we studied the association with Wolbachia in 12 diploid and 11 haplodiploid scolytine beetles by analyzing wsp and multilocus sequence typing (MLST) of five loci in this endosymbiont. Wolbachia genotypes were compared with mitochondrial (COI) and nuclear (EF) genotypes in the scolytines. Eight of the 23 scolytine species were infected with Wolbachia, with haplodiploids at significantly higher rates than diploid species. Cloning and sequencing detected multiple infections with up to six Wolbachia strains in individual species. Phylogenetic analyses of wsp and five MLST genes revealed different Wolbachia strains in scolytines. Comparisons between the beetle and Wolbachia phylogenies revealed that closely related beetles were infected with genetically different Wolbachia strains. These results suggest the horizontal transmission of multiple Wolbachia strains between scolytines. We discuss these results in terms of the evolution of different sex determination systems in scolytine beetles. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  9. Symbionts Commonly Provide Broad Spectrum Resistance to Viruses in Insects: A Comparative Analysis of Wolbachia Strains

    PubMed Central

    Martinez, Julien; Longdon, Ben; Bauer, Simone; Chan, Yuk-Sang; Miller, Wolfgang J.; Bourtzis, Kostas; Teixeira, Luis; Jiggins, Francis M.

    2014-01-01

    In the last decade, bacterial symbionts have been shown to play an important role in protecting hosts against pathogens. Wolbachia, a widespread symbiont in arthropods, can protect Drosophila and mosquito species against viral infections. We have investigated antiviral protection in 19 Wolbachia strains originating from 16 Drosophila species after transfer into the same genotype of Drosophila simulans. We found that approximately half of the strains protected against two RNA viruses. Given that 40% of terrestrial arthropod species are estimated to harbour Wolbachia, as many as a fifth of all arthropods species may benefit from Wolbachia-mediated protection. The level of protection against two distantly related RNA viruses – DCV and FHV – was strongly genetically correlated, which suggests that there is a single mechanism of protection with broad specificity. Furthermore, Wolbachia is making flies resistant to viruses, as increases in survival can be largely explained by reductions in viral titer. Variation in the level of antiviral protection provided by different Wolbachia strains is strongly genetically correlated to the density of the bacteria strains in host tissues. We found no support for two previously proposed mechanisms of Wolbachia-mediated protection — activation of the immune system and upregulation of the methyltransferase Dnmt2. The large variation in Wolbachia's antiviral properties highlights the need to carefully select Wolbachia strains introduced into mosquito populations to prevent the transmission of arboviruses. PMID:25233341

  10. Quantitative Proteomic Analyses of Molecular Mechanisms Associated with Cytoplasmic Incompatibility in Drosophila melanogaster Induced by Wolbachia.

    PubMed

    Yuan, Lin-Ling; Chen, Xiulan; Zong, Qiong; Zhao, Ting; Wang, Jia-Lin; Zheng, Ya; Zhang, Ming; Wang, Zailong; Brownlie, Jeremy C; Yang, Fuquan; Wang, Yu-Feng

    2015-09-04

    To investigate the molecular mechanisms of cytoplasmic incompatibility (CI) induced by Wolbachia bacteria in Drosophila melanogaster, we applied an isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomic assay to identify differentially expressed proteins extracted from spermathecae and seminal receptacles (SSR) of uninfected females mated with either 1-day-old Wolbachia-uninfected (1T) or infected males (1W) or 5-day-old infected males (5W). In total, 1317 proteins were quantified; 83 proteins were identified as having at least a 1.5-fold change in expression when 1W was compared with 1T. Differentially expressed proteins were related to metabolism, immunity, and reproduction. Wolbachia changed the expression of seminal fluid proteins (Sfps). Wolbachia may disrupt the abundance of proteins in SSR by affecting ubiquitin-proteasome-mediated proteolysis. Knocking down two Sfp genes (CG9334 and CG2668) in Wolbachia-free males resulted in significantly lower embryonic hatch rates with a phenotype of chromatin bridges. Wolbachia-infected females may rescue the hatch rates. This suggests that the changed expression of some Sfps may be one of the mechanisms of CI induced by Wolbachia. This study provides a panel of candidate proteins that may be involved in the interaction between Wolbachia and their insect hosts and, through future functional studies, may help to elucidate the underlying mechanisms of Wolbachia-induced CI.

  11. [Drosophila melanogaster Cell Culture as an Experimental Model to Study Recombination in Wolbachia pipientis].

    PubMed

    Goryacheva, I I; Gorelova, T V; Andrianov, B V

    2015-12-01

    Wolbachiapipientis is an obligate intracellular endosymbiont that commonly infects arthropods. Comparative genomic studies of Wolbachia reveal traces of numerous events of intergenic and intragenic recombination. The molecular mechanisms of recombination in Wolbachia are not currently known. We conducted experimental verification of the possibility of recombination of two strains of Wolbachia: wMel and wRi, after using these strains for double infection of the Dm2008Wb1 (D. melanogaster) cell culture clone permissive to Wolbachia. We obtained cell culture subclones with double Wolbachia infection and subclones infected only by strain wMel. Dual infection with the Wolbachia strains wMel and wRi has been stably maintained in the subclones for two years. Multilocus sequence typing (MLST) of the obtained subclones revealed the presence of dual infection for all five Wolbachia genes used for MLST Cloning and nucleotide sequence analysis of individual forms of the fbpA gene of Wolbachia from cell clones with dual infection showed intragenic recombination events between strains wMel and wRi, which occurred in the permanent D. melanogaster culture cell culture. The fact that putative recombination sites contain no insertions of nucleotide sequences of phages or IS elements, as well as the asymmetrical character of recombinants, favors the hypothesis that gene conversion is the most probable molecular mechanism of recombination in Wolbachia.

  12. Mitochondrial DNA variants help monitor the dynamics of Wolbachia invasion into host populations.

    PubMed

    Yeap, H L; Rašić, G; Endersby-Harshman, N M; Lee, S F; Arguni, E; Le Nguyen, H; Hoffmann, A A

    2016-03-01

    Wolbachia is the most widespread endosymbiotic bacterium of insects and other arthropods that can rapidly invade host populations. Deliberate releases of Wolbachia into natural populations of the dengue fever mosquito, Aedes aegypti, are used as a novel biocontrol strategy for dengue suppression. Invasion of Wolbachia through the host population relies on factors such as high fidelity of the endosymbiont transmission and limited immigration of uninfected individuals, but these factors can be difficult to measure. One way of acquiring relevant information is to consider mitochondrial DNA (mtDNA) variation alongside Wolbachia in field-caught mosquitoes. Here we used diagnostic mtDNA markers to differentiate infection-associated mtDNA haplotypes from those of the uninfected mosquitoes at release sites. Unique haplotypes associated with Wolbachia were found at locations outside Australia. We also performed mathematical and qualitative analyses including modelling the expected dynamics of the Wolbachia and mtDNA variants during and after a release. Our analyses identified key features in haplotype frequency patterns to infer the presence of imperfect maternal transmission of Wolbachia, presence of immigration and possibly incomplete cytoplasmic incompatibility. We demonstrate that ongoing screening of the mtDNA variants should provide information on maternal leakage and immigration, particularly in releases outside Australia. As we demonstrate in a case study, our models to track the Wolbachia dynamics can be successfully applied to temporal studies in natural populations or Wolbachia release programs, as long as there is co-occurring mtDNA variation that differentiates infected and uninfected populations.

  13. 33 CFR 104.106 - Passenger access area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SECURITY MARITIME SECURITY: VESSELS General § 104.106 Passenger access area. (a) A ferry, passenger vessel... measures for access control, of a ferry, passenger vessel, or cruise ship that is open to passengers. It is...

  14. 33 CFR 104.106 - Passenger access area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., or cruise ship may designate areas within the vessel as passenger access areas. (b) A passenger... measures for access control, of a ferry, passenger vessel, or cruise ship that is open to passengers. It...

  15. 33 CFR 104.106 - Passenger access area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., or cruise ship may designate areas within the vessel as passenger access areas. (b) A passenger... measures for access control, of a ferry, passenger vessel, or cruise ship that is open to passengers. It...

  16. 33 CFR 104.106 - Passenger access area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., or cruise ship may designate areas within the vessel as passenger access areas. (b) A passenger... measures for access control, of a ferry, passenger vessel, or cruise ship that is open to passengers. It...

  17. 33 CFR 104.106 - Passenger access area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., or cruise ship may designate areas within the vessel as passenger access areas. (b) A passenger... measures for access control, of a ferry, passenger vessel, or cruise ship that is open to passengers. It...

  18. Locating influential nodes in complex networks

    PubMed Central

    Malliaros, Fragkiskos D.; Rossi, Maria-Evgenia G.; Vazirgiannis, Michalis

    2016-01-01

    Understanding and controlling spreading processes in networks is an important topic with many diverse applications, including information dissemination, disease propagation and viral marketing. It is of crucial importance to identify which entities act as influential spreaders that can propagate information to a large portion of the network, in order to ensure efficient information diffusion, optimize available resources or even control the spreading. In this work, we capitalize on the properties of the K-truss decomposition, a triangle-based extension of the core decomposition of graphs, to locate individual influential nodes. Our analysis on real networks indicates that the nodes belonging to the maximal K-truss subgraph show better spreading behavior compared to previously used importance criteria, including node degree and k-core index, leading to faster and wider epidemic spreading. We further show that nodes belonging to such dense subgraphs, dominate the small set of nodes that achieve the optimal spreading in the network. PMID:26776455

  19. Locating influential nodes in complex networks

    NASA Astrophysics Data System (ADS)

    Malliaros, Fragkiskos D.; Rossi, Maria-Evgenia G.; Vazirgiannis, Michalis

    2016-01-01

    Understanding and controlling spreading processes in networks is an important topic with many diverse applications, including information dissemination, disease propagation and viral marketing. It is of crucial importance to identify which entities act as influential spreaders that can propagate information to a large portion of the network, in order to ensure efficient information diffusion, optimize available resources or even control the spreading. In this work, we capitalize on the properties of the K-truss decomposition, a triangle-based extension of the core decomposition of graphs, to locate individual influential nodes. Our analysis on real networks indicates that the nodes belonging to the maximal K-truss subgraph show better spreading behavior compared to previously used importance criteria, including node degree and k-core index, leading to faster and wider epidemic spreading. We further show that nodes belonging to such dense subgraphs, dominate the small set of nodes that achieve the optimal spreading in the network.

  20. Reliance of Wolbachia on High Rates of Host Proteolysis Revealed by a Genome-Wide RNAi Screen of Drosophila Cells.

    PubMed

    White, Pamela M; Serbus, Laura R; Debec, Alain; Codina, Adan; Bray, Walter; Guichet, Antoine; Lokey, R Scott; Sullivan, William

    2017-04-01

    Wolbachia are gram-negative, obligate, intracellular bacteria carried by a majority of insect species worldwide. Here we use a Wolbachia-infected Drosophila cell line and genome-wide RNA interference (RNAi) screening to identify host factors that influence Wolbachia titer. By screening an RNAi library targeting 15,699 transcribed host genes, we identified 36 candidate genes that dramatically reduced Wolbachia titer and 41 that increased Wolbachia titer. Host gene knockdowns that reduced Wolbachia titer spanned a broad array of biological pathways including genes that influenced mitochondrial function and lipid metabolism. In addition, knockdown of seven genes in the host ubiquitin and proteolysis pathways significantly reduced Wolbachia titer. To test the in vivo relevance of these results, we found that drug and mutant inhibition of proteolysis reduced levels of Wolbachia in the Drosophila oocyte. The presence of Wolbachia in either cell lines or oocytes dramatically alters the distribution and abundance of ubiquitinated proteins. Functional studies revealed that maintenance of Wolbachia titer relies on an intact host Endoplasmic Reticulum (ER)-associated protein degradation pathway (ERAD). Accordingly, electron microscopy studies demonstrated that Wolbachia is intimately associated with the host ER and dramatically alters the morphology of this organelle. Given Wolbachia lack essential amino acid biosynthetic pathways, the reliance of Wolbachia on high rates of host proteolysis via ubiquitination and the ERAD pathways may be a key mechanism for provisioning Wolbachia with amino acids. In addition, the reliance of Wolbachia on the ERAD pathway and disruption of ER morphology suggests a previously unsuspected mechanism for Wolbachia's potent ability to prevent RNA virus replication. Copyright © 2017 by the Genetics Society of America.

  1. 76 FR 28998 - Implementation of Revised Passenger Weight Standards for Existing Passenger Vessels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-19

    ... SECURITY Coast Guard Implementation of Revised Passenger Weight Standards for Existing Passenger Vessels... Passenger Weight Standards for Existing Passenger Vessels.'' This policy letter provides guidance on how the... person standard that will become effective in December 2011. DATES: The policy letter announced in this...

  2. Wolbachia Infection Decreased the Resistance of Drosophila to Lead

    PubMed Central

    Wang, Ling; Zhou, Chun; He, Zhen; Wang, Zheng-Guang; Wang, Jia-Lin; Wang, Yu-Feng

    2012-01-01

    Background The heavy metal lead has been shown to be associated with a genotoxic risk. Drosophila melanogaster is a model organism commonly utilized in genetic toxicology testing. The endosymbionts — Wolbachia are now very common in both wild populations and laboratory stocks of Drosophila. Wolbachia may induce resistance to pathogenic viruses, filarial nematodes and Plasmodium in fruit fly and mosquito hosts. However the effect of Wolbachia infection on the resistance of their hosts to heavy metal is unknown. Methodology/Principal Findings Manipulating the lead content in the diet of Drosophila melanogaster, we found that lead consumption had no different effects on developmental time between Wolbachia-infected (Dmel wMel) and –uninfected (Dmel T) flies. While in Pb-contaminated medium, significantly reduced amount of pupae and adults of Dmel wMel were emerged, and Dmel wMel adults had significantly shorter longevity than that of Dmel T flies. Lead infusion in diet resulted in significantly decreased superoxide dismutase (SOD) activity in Dmel T flies (P<0.05), but not in Dmel wMel flies. Correspondingly, lead cultures induced a 10.8 fold increase in malonaldehyde (MDA) contents in Dmel T larvae (P<0.05). While in Dmel wMel larvae, it resulted in only a 1.3 fold increase. By quantitative RT-PCR, we showed that lead infused medium caused significantly increased expression level of relish and CecA2 genes in Dmel T flies (P<0.01). Lead cultures did not change dramatically the expression of these genes in Dmel wMel flies. Conclusions/Significance These results suggest that Wolbachia infection decreased the resistance of Drosophila to lead likely by limiting the production of peroxides resulted from lead, thus being unable to activate the immunological pathway in the host to prevent them from lead damage. This represents a novel Wolbachia–host interaction and provides information that researchers working on Drosophila toxicology should take in consideration the

  3. Absence of Wolbachia endobacteria in the human parasitic nematode Dracunculus medinensis and two related Dracunculus species infecting wildlife

    PubMed Central

    2014-01-01

    Background Wolbachia endosymbionts are a proven target for control of human disease caused by filarial nematodes. However, little is known about the occurrence of Wolbachia in taxa closely related to the superfamily Filarioidea. Our study addressed the status of Wolbachia presence in members of the superfamily Dracunculoidea by screening the human parasite Dracunculus medinensis and related species from wildlife for Wolbachia. Findings D. medinensis, D. lutrae and D. insignis specimens were all negative for Wolbachia colonization by PCR screening for the Wolbachia ftsZ, 16S rRNA and Wolbachia surface protein (wsp) sequences. The quality and purity of the DNA preparations was confirmed by amplification of nematode 18S rRNA and cytochrome c oxidase subunit I sequences. Furthermore, Wolbachia endobacteria were not detected by whole mount fluorescence staining, or by immunohistochemistry using a Wolbachia-specific antiserum. In contrast, positive control Brugia malayi worms were shown to harbour Wolbachia by PCR, fluorescence staining and immunohistochemistry. Conclusions Three examined species of Dracunculus showed no evidence of Wolbachia endobacteria. This supports that members of the superfamily Dracunculoidea are free of Wolbachia. Within the order Spirurida, these endosymbionts appear restricted to the Filarioidea. PMID:24685011

  4. 14 CFR 125.217 - Passenger information.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Seat Belt” sign is lighted. (d) Each passenger shall comply with instructions given him or her by... them when smoking is prohibited and when safety belts must be fastened. The signs must be so... passenger or crewmember smoke in any lavatory. (c) Each passenger required by § 125.211(b) to occupy a...

  5. 49 CFR 523.4 - Passenger automobile.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 6 2012-10-01 2012-10-01 false Passenger automobile. 523.4 Section 523.4... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.4 Passenger automobile. A passenger automobile is any automobile (other than an automobile capable of off-highway operation)...

  6. 49 CFR 523.4 - Passenger automobile.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 6 2013-10-01 2013-10-01 false Passenger automobile. 523.4 Section 523.4... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.4 Passenger automobile. A passenger automobile is any automobile (other than an automobile capable of off-highway operation)...

  7. 49 CFR 523.4 - Passenger automobile.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 6 2014-10-01 2014-10-01 false Passenger automobile. 523.4 Section 523.4... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.4 Passenger automobile. A passenger automobile is any automobile (other than an automobile capable of off-highway operation)...

  8. 49 CFR 523.4 - Passenger automobile.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 6 2011-10-01 2011-10-01 false Passenger automobile. 523.4 Section 523.4... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.4 Passenger automobile. A passenger automobile is any automobile (other than an automobile capable of off-highway operation)...

  9. 14 CFR 91.1035 - Passenger awareness.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... orally briefed on— (1) Smoking: Each passenger must be briefed on when, where, and under what conditions smoking is prohibited. This briefing must include a statement, as appropriate, that the regulations require passenger compliance with lighted passenger information signs and no smoking placards,...

  10. 14 CFR 91.1035 - Passenger awareness.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... orally briefed on— (1) Smoking: Each passenger must be briefed on when, where, and under what conditions smoking is prohibited. This briefing must include a statement, as appropriate, that the regulations require passenger compliance with lighted passenger information signs and no smoking placards,...

  11. 14 CFR 91.517 - Passenger information.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... smoking is prohibited and when safety belts must be fastened. The signs must be so constructed that the... belts and when smoking is prohibited. (c) If passenger information signs are installed, no passenger or crewmember may smoke while any “no smoking” sign is lighted nor may any passenger or crewmember smoke in...

  12. 14 CFR 91.517 - Passenger information.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... smoking is prohibited and when safety belts must be fastened. The signs must be so constructed that the... belts and when smoking is prohibited. (c) If passenger information signs are installed, no passenger or crewmember may smoke while any “no smoking” sign is lighted nor may any passenger or crewmember smoke in...

  13. 14 CFR 91.517 - Passenger information.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... smoking is prohibited and when safety belts must be fastened. The signs must be so constructed that the... belts and when smoking is prohibited. (c) If passenger information signs are installed, no passenger or crewmember may smoke while any “no smoking” sign is lighted nor may any passenger or crewmember smoke in...

  14. 14 CFR 91.517 - Passenger information.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... smoking is prohibited and when safety belts must be fastened. The signs must be so constructed that the... belts and when smoking is prohibited. (c) If passenger information signs are installed, no passenger or crewmember may smoke while any “no smoking” sign is lighted nor may any passenger or crewmember smoke in...

  15. 14 CFR 91.519 - Passenger briefing.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... briefed on— (1) Smoking. Each passenger shall be briefed on when, where, and under what conditions smoking... Regulations require passenger compliance with lighted passenger information signs and no smoking placards, prohibit smoking in lavatories, and require compliance with crewmember instructions with regard to...

  16. 14 CFR 91.519 - Passenger briefing.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... briefed on— (1) Smoking. Each passenger shall be briefed on when, where, and under what conditions smoking... Regulations require passenger compliance with lighted passenger information signs and no smoking placards, prohibit smoking in lavatories, and require compliance with crewmember instructions with regard to...

  17. 14 CFR 91.519 - Passenger briefing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... briefed on— (1) Smoking. Each passenger shall be briefed on when, where, and under what conditions smoking... Regulations require passenger compliance with lighted passenger information signs and no smoking placards, prohibit smoking in lavatories, and require compliance with crewmember instructions with regard to...

  18. 14 CFR 91.519 - Passenger briefing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... briefed on— (1) Smoking. Each passenger shall be briefed on when, where, and under what conditions smoking... Regulations require passenger compliance with lighted passenger information signs and no smoking placards, prohibit smoking in lavatories, and require compliance with crewmember instructions with regard to...

  19. 14 CFR 91.519 - Passenger briefing.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Regulations require passenger compliance with lighted passenger information signs and no smoking placards, prohibit smoking in lavatories, and require compliance with crewmember instructions with regard to these... briefed on— (1) Smoking. Each passenger shall be briefed on when, where, and under what conditions...

  20. 49 CFR 523.4 - Passenger automobile.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Passenger automobile. 523.4 Section 523.4... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.4 Passenger automobile. A passenger automobile is any automobile (other than an automobile capable of off-highway operation)...

  1. Cytoplasmic incompatibility and sperm cyst infection in different Drosophila-Wolbachia associations.

    PubMed Central

    Veneti, Zoe; Clark, Michael E; Zabalou, Sofia; Karr, Timothy L; Savakis, Charalambos; Bourtzis, Kostas

    2003-01-01

    Wolbachia are a group of maternally transmitted obligatory intracellular alpha-proteobacteria that infect a wide range of arthropod and nematode species. Wolbachia infection in Drosophila in most cases is associated with the induction of cytoplasmic incompatibility (CI), manifested as embryonic lethality of offspring in a cross between infected males and uninfected females. While the molecular basis of CI is still unknown, it has been suggested that two bacterial functions are involved: mod (for modification) modifies the sperm during spermatogenesis and resc (for rescue) acts in the female germline and/or in early embryos, neutralizing the modification. There is considerable variation in the level of incompatibility in different Wolbachia/host interactions. We examine the relationship between the levels of CI in a number of naturally infected and transinfected Drosophila hosts and the percentage of Wolbachia-infected sperm cysts. Our results indicate the presence of two main groups of Drosophila-Wolbachia associations: group I, which exhibits a positive correlation between CI levels and the percentage of infected sperm cysts (mod(+) phenotype), and group II, which does not express CI (mod(-) phenotype) irrespective of the infection status of the sperm cysts. Group II can be further divided into two subgroups: The first one contains associations with high numbers of heavily Wolbachia-infected sperm cysts while in the second one, Wolbachia is rarely detected in sperm cysts, being mostly present in somatic cells. We conclude that there are three requirements for the expression of CI in a host-Wolbachia association: (a) Wolbachia has to be able to modify sperm (mod(+) genotype), (b) Wolbachia has to infect sperm cysts, and (c) Wolbachia has to be harbored by a permissive host. PMID:12807775

  2. Detection of Wolbachia endobacteria in Culex quinquefasciatus by Gimenez staining and confirmation by PCR.

    PubMed

    Muniaraj, M; Paramasivan, R; Sunish, I P; Arunachalam, N; Mariappan, T; Jerald Leo, S Victor; Dhananjeyan, K J

    2012-12-01

    Wolbachia are common intracellular bacteria that are found in arthropods and nematodes. These endosymbionts are transmitted vertically through host eggs and alter host biology in diverse ways, including the induction of reproductive manipulations, such as feminization, parthenogenesis, male killing and sperm-egg incompatibility. Since they can also move horizontally across species boundaries, Wolbachia is gaining importance in recent days as it could be used as a biological control agent to control vector mosquitoes or for paratransgenic approaches. However, the study of Wolbachia requires sophisticated techniques such as PCR and cell culture facilities which cannot be affordable for many laboratories where the diseases transmitted by arthropod vectors are common. Hence, it would be beneficial to develop a simple method to detect the presence of Wolbachia in arthropods. In this study, we described a method of staining Wolbachia endobacteria, present in the reproductive tissues of mosquitoes. The reliability of this method was compared with Gram staining and PCR based detection. The microscopic observation of the Gimenez stained smear prepared from the teased ovary of wild caught and Wolbachia (+) Cx. quinquefasciatus revealed the presence of pink coloured pleomorphic cells of Wolbachia ranging from cocci, comma shaped cells to bacillus and chain forms. The ovaries of Wolbachia (-) cured mosquito did not show any cell. Although Gram's staining is a reliable differential staining for the other bacteria, the bacterial cells in the smears from the ovaries of wild caught mosquitoes did not take the stain properly and the cells were not clearly visible. The PCR amplified product from the pooled remains of wild caught and Wolbachia (+) Cx. quinquefasciatus showed clear banding, whereas, no banding was observed for the negative control (distilled water) and Wolbachia (-) Cx. quinquefasciatus. The Gimenez staining technique applied, could be used to detect the members of

  3. Wolbachia-Based Dengue Virus Inhibition Is Not Tissue-Specific in Aedes aegypti.

    PubMed

    Amuzu, Hilaria E; McGraw, Elizabeth A

    2016-11-01

    Dengue fever, caused by the dengue virus (DENV), is now the most common arbovirus transmitted disease globally. One novel approach to control DENV is to use the endosymbiotic bacterium, Wolbachia pipientis, to limit DENV replication inside the primary mosquito vector, Aedes aegypti. Wolbachia that is naturally present in a range of insects reduces the capacity for viruses, bacteria, parasites and fungi to replicate inside insects. Wolbachia's mode of action is not well understood but may involve components of immune activation or competition with pathogens for limited host resources. The strength of Wolbachia-based anti DENV effects appear to correlate with bacterial density in the whole insect and in cell culture. Here we aimed to determine whether particular tissues, especially those with high Wolbachia densities or immune activity, play a greater role in mediating the anti DENV effect. Ae. aegypti mosquito lines with and without Wolbachia (Wildtype) were orally fed DENV 3 and their viral loads subsequently measured over two time points post infection in the midgut, head, salivary glands, Malpighian tubules, fat body and carcass. We did not find correlations between Wolbachia densities and DENV loads in any tissue, nor with DENV loads in salivary glands, the endpoint of infection. This is in contrast with strong positive correlations between DENV loads in a range of tissues and salivary gland loads for Wildtype mosquitoes. Lastly, there was no evidence of a heightened role for tissues with known immune function including the fat body and the Malpighian tubules in Wolbachia's limitation of DENV. We conclude that the efficacy of DENV blocking in Wolbachia infected mosquitoes is not reliant on any particular tissue. This work therefore suggests that the mechanism of Wolbachia-based antiviral effects is either systemic or acts locally via processes that are fundamental to diverse cell types. We further conclude that the relationship between DENV blocking and

  4. Wolbachia-Mediated Antiviral Protection in Drosophila Larvae and Adults following Oral Infection

    PubMed Central

    Stevanovic, Aleksej L.; Arnold, Pieter A.

    2015-01-01

    Understanding viral dynamics in arthropods is of great importance when designing models to describe how viral spread can influence arthropod populations. The endosymbiotic bacterium Wolbachia spp., which is present in up to 40% of all insect species, has the ability to alter viral dynamics in both Drosophila spp. and mosquitoes, a feature that in mosquitoes may be utilized to limit spread of important arboviruses. To understand the potential effect of Wolbachia on viral dynamics in nature, it is important to consider the impact of natural routes of virus infection on Wolbachia antiviral effects. Using adult Drosophila strains, we show here that Drosophila-Wolbachia associations that have previously been shown to confer antiviral protection following systemic viral infection also confer protection against virus-induced mortality following oral exposure to Drosophila C virus in adults. Interestingly, a different pattern was observed when the same fly lines were challenged with the virus when still larvae. Analysis of the four Drosophila-Wolbachia associations that were protective in adults indicated that only the w1118-wMelPop association conferred protection in larvae following oral delivery of the virus. Analysis of Wolbachia density using quantitative PCR (qPCR) showed that a high Wolbachia density was congruent with antiviral protection in both adults and larvae. This study indicates that Wolbachia-mediated protection may vary between larval and adult stages of a given Wolbachia-host combination and that the variations in susceptibility by life stage correspond with Wolbachia density. The differences in the outcome of virus infection are likely to influence viral dynamics in Wolbachia-infected insect populations in nature and could also have important implications for the transmission of arboviruses in mosquito populations. PMID:26407882

  5. Wolbachia-mediated antiviral protection in Drosophila larvae and adults following oral infection.

    PubMed

    Stevanovic, Aleksej L; Arnold, Pieter A; Johnson, Karyn N

    2015-12-01

    Understanding viral dynamics in arthropods is of great importance when designing models to describe how viral spread can influence arthropod populations. The endosymbiotic bacterium Wolbachia spp., which is present in up to 40% of all insect species, has the ability to alter viral dynamics in both Drosophila spp. and mosquitoes, a feature that in mosquitoes may be utilized to limit spread of important arboviruses. To understand the potential effect of Wolbachia on viral dynamics in nature, it is important to consider the impact of natural routes of virus infection on Wolbachia antiviral effects. Using adult Drosophila strains, we show here that Drosophila-Wolbachia associations that have previously been shown to confer antiviral protection following systemic viral infection also confer protection against virus-induced mortality following oral exposure to Drosophila C virus in adults. Interestingly, a different pattern was observed when the same fly lines were challenged with the virus when still larvae. Analysis of the four Drosophila-Wolbachia associations that were protective in adults indicated that only the w1118-wMelPop association conferred protection in larvae following oral delivery of the virus. Analysis of Wolbachia density using quantitative PCR (qPCR) showed that a high Wolbachia density was congruent with antiviral protection in both adults and larvae. This study indicates that Wolbachia-mediated protection may vary between larval and adult stages of a given Wolbachia-host combination and that the variations in susceptibility by life stage correspond with Wolbachia density. The differences in the outcome of virus infection are likely to influence viral dynamics in Wolbachia-infected insect populations in nature and could also have important implications for the transmission of arboviruses in mosquito populations. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  6. Wolbachia lipoproteins: abundance, localisation and serology of Wolbachia peptidoglycan associated lipoprotein and the Type IV Secretion System component, VirB6 from Brugia malayi and Aedes albopictus.

    PubMed

    Voronin, Denis; Guimarães, Ana F; Molyneux, Gemma R; Johnston, Kelly L; Ford, Louise; Taylor, Mark J

    2014-10-06

    Lipoproteins are the major agonists of Wolbachia-dependent inflammatory pathogenesis in filariasis and a validated target for drug discovery. Here we characterise the abundance, localisation and serology of the Wolbachia lipoproteins: Wolbachia peptidoglycan associated lipoprotein and the Type IV Secretion System component, VirB6. We used proteomics to confirm lipoprotein presence and relative abundance; fractionation, immunoblotting and confocal and electron immuno-microscopy for localisation and ELISA for serological analysis. Proteomic analysis of Brugia malayi adult female protein extracts confirmed the presence of two lipoproteins, previously predicted through bioinformatics: Wolbachia peptidoglycan associated lipoprotein (wBmPAL) and the Type IV Secretion System component, VirB6 (wBmVirB6). wBmPAL was among the most abundant Wolbachia proteins present in an extract of adult female worms with wBmVirB6 only detected at a much lower abundance. This differential abundance was reflected in the immunogold-labelling, which showed wBmPAL localised at numerous sites within the bacterial membranes, whereas wBmVirB6 was present as a single cluster on each bacterial cell and also located within the bacterial membranes. Immunoblotting of fractionated extracts confirmed the localisation of wBmPAL to membranes and its absence from cytosolic fractions of C6/36 mosquito cells infected with wAlbB. In whole worm mounts, antibody labelling of both lipoproteins were associated with Wolbachia. Serological analysis showed that both proteins were immunogenic and raised antibody responses in the majority of individuals infected with Wuchereria bancrofti. Two Wolbachia lipoproteins, wBmPAL and wBmVirB6, are present in extracts of Brugia malayi with wBmPAL among the most abundant of Wolbachia proteins. Both lipoproteins localised to bacterial membranes with wBmVirB6 present as a single cluster suggesting a single Type IV Secretory System on each Wolbachia cell.

  7. Determinants of injuries in passenger vessel accidents.

    PubMed

    Yip, Tsz Leung; Jin, Di; Talley, Wayne K

    2015-09-01

    This paper investigates determinants of crew and passenger injuries in passenger vessel accidents. Crew and passenger injury equations are estimated for ferry, ocean cruise, and river cruise vessel accidents, utilizing detailed data of individual vessel accidents that were investigated by the U.S. Coast Guard during the time period 2001-2008. The estimation results provide empirical evidence (for the first time in the literature) that crew injuries are determinants of passenger injuries in passenger vessel accidents. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Cannibalism and predation as paths for horizontal passage of Wolbachia between terrestrial isopods.

    PubMed

    Le Clec'h, Winka; Chevalier, Frédéric D; Genty, Lise; Bertaux, Joanne; Bouchon, Didier; Sicard, Mathieu

    2013-01-01

    The alpha-proteobacteria Wolbachia are the most widespread endosymbionts in arthropods and nematodes. Mainly maternally inherited, these so-called sex parasites have selected several strategies that increase their vertical dispersion in host populations. However, the lack of congruence between the Wolbachia and their host phylogenies suggests frequent horizontal transfers. One way that could be used for horizontal Wolbachia transfers between individuals is predation. The aim of this study was to test whether horizontal passage of Wolbachia is possible when an uninfected terrestrial isopod eats an infected one. After having eaten Armadillidium vulgare harbouring Wolbachia, the predator-recipients (the two woodlice A. vulgare and Porcellio dilatatus dilatatus) that were initially Wolbachia-free were tested positive for the presence of Wolbachia both by quantitative PCR and Fluorescence in situ Hybridization (FISH). Even if the titers were low compared to vertically infected individuals, this constitutes the first demonstration of Wolbachia occurrence in various organs of an initially uninfected host after eating an infected one.

  9. The potential role of Wolbachia in controlling the transmission of emerging human arboviral infections

    PubMed Central

    Kamtchum-Tatuene, Joseph; Makepeace, Benjamin L.; Benjamin, Laura; Baylis, Matthew; Solomon, Tom

    2017-01-01

    Purpose of review Wolbachia is a genus of Gram-negative intracellular bacteria that is naturally found in more than half of all arthropod species. These bacteria cannot only reduce the fitness and the reproductive capacities of arthropod vectors, but also increase their resistance to arthropod-borne viruses (arboviruses). This article reviews the evidence supporting a Wolbachia-based strategy for controlling the transmission of dengue and other arboviral infections. Recent findings Studies conducted 1 year after the field release of Wolbachia-infected mosquitoes in Australia have demonstrated the suppression of dengue virus (DENV) replication in and dissemination by mosquitoes. Recent mathematical models show that this strategy could reduce the transmission of DENV by 70%. Consequently, the WHO is encouraging countries to boost the development and implementation of Wolbachia-based prevention strategies against other arboviral infections. However, the evidence regarding the efficacy of Wolbachia to prevent the transmission of other arboviral infections is still limited to an experimental framework with conflicting results in some cases. There is a need to demonstrate the efficacy of such strategies in the field under various climatic conditions, to select the Wolbachia strain that has the best pathogen interference/spread trade-off, and to continue to build community acceptance. Summary Wolbachia represents a promising tool for controlling the transmission of arboviral infections that needs to be developed further. Long-term environmental monitoring will be necessary for timely detection of potential changes in Wolbachia/vector/virus interactions. PMID:27849636

  10. Chaos of Wolbachia sequences inside the compact fig syconia of Ficus benjamina (Ficus: moraceae).

    PubMed

    Yang, Chun-Yan; Xiao, Jin-Hua; Niu, Li-Ming; Ma, Guang-Chang; Cook, James M; Bian, Sheng-Nan; Fu, Yue-Guan; Huang, Da-Wei

    2012-01-01

    Figs and fig wasps form a peculiar closed community in which the Ficus tree provides a compact syconium (inflorescence) habitat for the lives of a complex assemblage of Chalcidoid insects. These diverse fig wasp species have intimate ecological relationships within the closed world of the fig syconia. Previous surveys of Wolbachia, maternally inherited endosymbiotic bacteria that infect vast numbers of arthropod hosts, showed that fig wasps have some of the highest known incidences of Wolbachia amongst all insects. We ask whether the evolutionary patterns of Wolbachia sequences in this closed syconium community are different from those in the outside world. In the present study, we sampled all 17 fig wasp species living on Ficus benjamina, covering 4 families, 6 subfamilies, and 8 genera of wasps. We made a thorough survey of Wolbachia infection patterns and studied evolutionary patterns in wsp (Wolbachia Surface Protein) sequences. We find evidence for high infection incidences, frequent recombination between Wolbachia strains, and considerable horizontal transfer, suggesting rapid evolution of Wolbachia sequences within the syconium community. Though the fig wasps have relatively limited contact with outside world, Wolbachia may be introduced to the syconium community via horizontal transmission by fig wasps species that have winged males and visit the syconia earlier.

  11. Wolbachia Divergence and the Evolution of Cytoplasmic Incompatibility in Culex pipiens

    PubMed Central

    Atyame, Célestine M.; Labbé, Pierrick; Dumas, Emilie; Milesi, Pascal; Charlat, Sylvain; Fort, Philippe; Weill, Mylène

    2014-01-01

    Many insect species harbor Wolbachia bacteria that induce cytoplasmic incompatibility (CI), i.e. embryonic lethality in crosses between infected males and uninfected females, or between males and females carrying incompatible Wolbachia strains. The molecular mechanism of CI remains unknown, but the available data are best interpreted under a modification–rescue model, where a mod function disables the reproductive success of infected males’ sperm, unless the eggs are infected and express a compatible resc function. Here we examine the evolution of CI in the mosquito Culex pipiens, harbouring a large number of closely related Wolbachia strains structured in five distinct phylogenetic groups. Specifically, we used a worldwide sample of mosquito lines to assess the hypothesis that genetic divergence should correlate with the divergence of CI properties on a low evolutionary scale. We observed a significant association of Wolbachia genetic divergence with CI patterns. Most Wolbachia strains from the same group were compatible whereas those from different groups were often incompatible. Consistently, we found a strong association between Wolbachia groups and their mod-resc properties. Finally, lines from the same geographical area were rarely incompatible, confirming the conjecture that the spatial distribution of Wolbachia compatibility types should be constrained by selection. This study indicates a clear correlation between Wolbachia genotypes and CI properties, paving the way toward the identification of the molecular basis of CI through comparative genomics. PMID:24498078

  12. A preliminary survey for Wolbachia and bacteriophage WO infections in Indian mosquitoes (Diptera: Culicidae).

    PubMed

    Ravikumar, H; Ramachandraswamy, N; Sampathkumar, S; Prakash, B M; Huchesh, H C; Uday, J; Puttaraju, H P

    2010-12-01

    Maternally inherited Wolbachia endosymbiotic bacteria are known to induce various kinds of reproductive alterations in their arthropod hosts. It has been proposed that this bacterium can be used as a tool for gene drive system in mosquitoes and also for the reduction of population size and modulating population age structure in order to reduce disease transmission. In the present study, we carried out a survey to determine the prevalence of Wolbachia and its phage WO infection in Indian mosquitoes and classified Wolbachia infection into groups A and B based on extensive polymerase chain reaction assay using Wolbachia specific wsp and orf7 gene primers. Out of 20 fieldcaught mosquito species, eight species have shown to be infected. Singly infected with Wolbachia A was found in two species and B group found in four species, while double infection with AB group were found in two species. All the screened mosquito species with positive Wolbachia infection were also infected with phage WO. The knowledge of variation in Wolbachia and phage WO infection rates and inferred susceptibility to infection among different mosquito genera has fundamental implications for designing and successful application of Wolbachia based vector-borne disease control strategies.

  13. Finding Wolbachia in Filarial larvae and Culicidae Mosquitoes in Upper Egypt Governorate.

    PubMed

    Dyab, Ahmed K; Galal, Lamia A; Mahmoud, Abeer E; Mokhtar, Yasser

    2016-06-01

    Wolbachia is an obligatory intracellular endosymbiotic bacterium, present in over 20% of all insects altering insect reproductive capabilities and in a wide range of filarial worms which is essential for worm survival and reproduction. In Egypt, no available data were found about Wolbachia searching for it in either mosquitoes or filarial worms. Thus, we aimed to identify the possible concurrent presence of Wolbachia within different mosquitoes and filarial parasites, in Assiut Governorate, Egypt using multiplex PCR. Initially, 6 pools were detected positive for Wolbachia by single PCR. The simultaneous detection of Wolbachia and filarial parasites (Wuchereria bancrofti, Dirofilaria immitis, and Dirofilaria repens) by multiplex PCR was spotted in 5 out of 6 pools, with an overall estimated rate of infection (ERI) of 0.24%. Unexpectedly, the highest ERI (0.53%) was for Anopheles pharoensis with related Wolbachia and W. bancrofti, followed by Aedes (0.42%) and Culex (0.26%). We also observed that Wolbachia altered Culex spp. as a primary vector for W. bancrofti to be replaced by Anopheles sp. Wolbachia within filaria-infected mosquitoes in our locality gives a hope to use bacteria as a new control trend simultaneously targeting the vector and filarial parasites.

  14. A Cell-Based Screen Reveals that the Albendazole Metabolite, Albendazole Sulfone, Targets Wolbachia

    PubMed Central

    Bray, Walter M.; White, Pamela M.; Ruybal, Jordan; Lokey, R. Scott; Debec, Alain; Sullivan, William

    2012-01-01

    Wolbachia endosymbionts carried by filarial nematodes give rise to the neglected diseases African river blindness and lymphatic filariasis afflicting millions worldwide. Here we identify new Wolbachia-disrupting compounds by conducting high-throughput cell-based chemical screens using a Wolbachia-infected, fluorescently labeled Drosophila cell line. This screen yielded several Wolbachia-disrupting compounds including three that resembled Albendazole, a widely used anthelmintic drug that targets nematode microtubules. Follow-up studies demonstrate that a common Albendazole metabolite, Albendazole sulfone, reduces intracellular Wolbachia titer both in Drosophila melanogaster and Brugia malayi, the nematode responsible for lymphatic filariasis. Significantly, Albendazole sulfone does not disrupt Drosophila microtubule organization, suggesting that this compound reduces titer through direct targeting of Wolbachia. Accordingly, both DNA staining and FtsZ immunofluorescence demonstrates that Albendazole sulfone treatment induces Wolbachia elongation, a phenotype indicative of binary fission defects. This suggests that the efficacy of Albendazole in treating filarial nematode-based diseases is attributable to dual targeting of nematode microtubules and their Wolbachia endosymbionts. PMID:23028321

  15. A cell-based screen reveals that the albendazole metabolite, albendazole sulfone, targets Wolbachia.

    PubMed

    Serbus, Laura R; Landmann, Frederic; Bray, Walter M; White, Pamela M; Ruybal, Jordan; Lokey, R Scott; Debec, Alain; Sullivan, William

    2012-09-01

    Wolbachia endosymbionts carried by filarial nematodes give rise to the neglected diseases African river blindness and lymphatic filariasis afflicting millions worldwide. Here we identify new Wolbachia-disrupting compounds by conducting high-throughput cell-based chemical screens using a Wolbachia-infected, fluorescently labeled Drosophila cell line. This screen yielded several Wolbachia-disrupting compounds including three that resembled Albendazole, a widely used anthelmintic drug that targets nematode microtubules. Follow-up studies demonstrate that a common Albendazole metabolite, Albendazole sulfone, reduces intracellular Wolbachia titer both in Drosophila melanogaster and Brugia malayi, the nematode responsible for lymphatic filariasis. Significantly, Albendazole sulfone does not disrupt Drosophila microtubule organization, suggesting that this compound reduces titer through direct targeting of Wolbachia. Accordingly, both DNA staining and FtsZ immunofluorescence demonstrates that Albendazole sulfone treatment induces Wolbachia elongation, a phenotype indicative of binary fission defects. This suggests that the efficacy of Albendazole in treating filarial nematode-based diseases is attributable to dual targeting of nematode microtubules and their Wolbachia endosymbionts.

  16. Finding Wolbachia in Filarial larvae and Culicidae Mosquitoes in Upper Egypt Governorate

    PubMed Central

    Dyab, Ahmed K.; Galal, Lamia A.; Mahmoud, Abeer E.; Mokhtar, Yasser

    2016-01-01

    Wolbachia is an obligatory intracellular endosymbiotic bacterium, present in over 20% of all insects altering insect reproductive capabilities and in a wide range of filarial worms which is essential for worm survival and reproduction. In Egypt, no available data were found about Wolbachia searching for it in either mosquitoes or filarial worms. Thus, we aimed to identify the possible concurrent presence of Wolbachia within different mosquitoes and filarial parasites, in Assiut Governorate, Egypt using multiplex PCR. Initially, 6 pools were detected positive for Wolbachia by single PCR. The simultaneous detection of Wolbachia and filarial parasites (Wuchereria bancrofti, Dirofilaria immitis, and Dirofilaria repens) by multiplex PCR was spotted in 5 out of 6 pools, with an overall estimated rate of infection (ERI) of 0.24%. Unexpectedly, the highest ERI (0.53%) was for Anopheles pharoensis with related Wolbachia and W. bancrofti, followed by Aedes (0.42%) and Culex (0.26%). We also observed that Wolbachia altered Culex spp. as a primary vector for W. bancrofti to be replaced by Anopheles sp. Wolbachia within filaria-infected mosquitoes in our locality gives a hope to use bacteria as a new control trend simultaneously targeting the vector and filarial parasites. PMID:27417080

  17. Diversity and phylogenetic relationships of Wolbachia in Drosophila and other native Hawaiian insects.

    PubMed

    Bennett, Gordon M; Pantoja, Norma A; O'Grady, Patrick M

    2012-01-01

    Wolbachia is a genus of parasitic alphaproteobacteria found in arthropods and nematodes, and represents on of the most common, widespread endosymbionts known. Wolbachia affects a variety of reproductive functions in its host (e.g., male killing, cytoplasmic incompatibility, parthenogenesis), which have the potential to dramatically impact host evolution and species formation. Here, we present the first broad-scale study to screen natural populations of native Hawaiian insects for Wolbachia, focusing on the endemic Diptera. Results indicate that Wolbachia infects native Hawaiian taxa, with alleles spanning phylogenetic supergroups, A and B. The overall frequency of Wolbachia incidene in Hawaiian insects was 14%. The incidence of infection in native Hawaiian Diptera was 11% for individuals and 12% for all species screened. Wolbachia was not detected in two large, widespread Hawaiian dipteran families-Dolichopodidae (44 spp screened) and Limoniidae (12 spp screened). Incidence of infection within endemic Hawaiian lineages that carry Wolbachia was 18% in Drosophilidae species, 25% in Caliphoridae species, > 90% in Nesophrosyne species, 20% in Drosophila dasycnemia and 100% in Nesophrosyne craterigena. Twenty unique alleles were recovered in this study, of which 18 are newly recorded. Screening of endemic populations of D. dasycnemia across Hawaii Island revealed 4 unique alleles. Phylogenetic relationships and allele diversity provide evidence for horizontal transfer of Wolbachia among Hawaiian arthropod lineages.

  18. Diversity and phylogenetic relationships of Wolbachia in Drosophila and other native Hawaiian insects

    PubMed Central

    Bennett, Gordon M.; Pantoja, Norma A.; O’Grady, Patrick M.

    2012-01-01

    Wolbachia is a genus of parasitic alphaproteobacteria found in arthropods and nematodes, and represents on of the most common, widespread endosymbionts known. Wolbachia affects a variety of reproductive functions in its host (e.g., male killing, cytoplasmic incompatibility, parthenogenesis), which have the potential to dramatically impact host evolution and species formation. Here, we present the first broad-scale study to screen natural populations of native Hawaiian insects for Wolbachia, focusing on the endemic Diptera. Results indicate that Wolbachia infects native Hawaiian taxa, with alleles spanning phylogenetic supergroups, A and B. The overall frequency of Wolbachia incidene in Hawaiian insects was 14%. The incidence of infection in native Hawaiian Diptera was 11% for individuals and 12% for all species screened. Wolbachia was not detected in two large, widespread Hawaiian dipteran families—Dolichopodidae (44 spp screened) and Limoniidae (12 spp screened). Incidence of infection within endemic Hawaiian lineages that carry Wolbachia was 18% in Drosophilidae species, 25% in Caliphoridae species, > 90% in Nesophrosyne species, 20% in Drosophila dasycnemia and 100% in Nesophrosyne craterigena. Twenty unique alleles were recovered in this study, of which 18 are newly recorded. Screening of endemic populations of D. dasycnemia across Hawaii Island revealed 4 unique alleles. Phylogenetic relationships and allele diversity provide evidence for horizontal transfer of Wolbachia among Hawaiian arthropod lineages. PMID:22878693

  19. Removing symbiotic Wolbachia bacteria specifically inhibits oogenesis in a parasitic wasp

    PubMed Central

    Dedeine, Franck; Vavre, Fabrice; Fleury, Frédéric; Loppin, Benjamin; Hochberg, Michael E.; Boulétreau, Michel

    2001-01-01

    Wolbachia are bacteria that live in the cells of various invertebrate species to which they cause a wide range of effects on physiology and reproduction. We investigated the effect of Wolbachia infection in the parasitic wasp, Asobara tabida Nees (Hymenoptera, Braconidae). In the 13 populations tested, all individuals proved to be infected by Wolbachia. The removal of Wolbachia by antibiotic treatment had a totally unexpected effect—aposymbiotic female wasps were completely incapable of producing mature oocytes and therefore could not reproduce. In contrast, oogenesis was not affected in treated Asobara citri, a closely related species that does not harbor Wolbachia. No difference between natural symbiotic and cured individuals was found for other adult traits including male fertility, locomotor activity, and size, indicating that the effect on oogenesis is highly specific. We argue that indirect effects of the treatments used in our study (antibiotic toxicity or production of toxic agents) are very unlikely to explain the sterility of females, and we present results showing a direct relationship between oocyte production and Wolbachia density in females. We conclude that Wolbachia is necessary for oogenesis in these A. tabida strains, and this association would seem to be the first example of a transition from facultative to obligatory symbiosis in arthropod–Wolbachia associations. PMID:11353833

  20. Chaos of Wolbachia Sequences Inside the Compact Fig Syconia of Ficus benjamina (Ficus: Moraceae)

    PubMed Central

    Niu, Li-Ming; Ma, Guang-Chang; Cook, James M.; Bian, Sheng-Nan; Fu, Yue-Guan; Huang, Da-Wei

    2012-01-01

    Figs and fig wasps form a peculiar closed community in which the Ficus tree provides a compact syconium (inflorescence) habitat for the lives of a complex assemblage of Chalcidoid insects. These diverse fig wasp species have intimate ecological relationships within the closed world of the fig syconia. Previous surveys of Wolbachia, maternally inherited endosymbiotic bacteria that infect vast numbers of arthropod hosts, showed that fig wasps have some of the highest known incidences of Wolbachia amongst all insects. We ask whether the evolutionary patterns of Wolbachia sequences in this closed syconium community are different from those in the outside world. In the present study, we sampled all 17 fig wasp species living on Ficus benjamina, covering 4 families, 6 subfamilies, and 8 genera of wasps. We made a thorough survey of Wolbachia infection patterns and studied evolutionary patterns in wsp (Wolbachia Surface Protein) sequences. We find evidence for high infection incidences, frequent recombination between Wolbachia strains, and considerable horizontal transfer, suggesting rapid evolution of Wolbachia sequences within the syconium community. Though the fig wasps have relatively limited contact with outside world, Wolbachia may be introduced to the syconium community via horizontal transmission by fig wasps species that have winged males and visit the syconia earlier. PMID:23145008

  1. Evidence for widespread Wolbachia infection in isopod crustaceans: molecular identification and host feminization.

    PubMed Central

    Bouchon, D; Rigaud, T; Juchault, P

    1998-01-01

    Wolbachia are maternally inherited, intracellular, alpha proteobacteria that infect a wide range of arthropods. They cause three kinds of reproductive alterations in their hosts: cytoplasmic incompatibility, parthenogenesis and feminization. There have been many studies of the distribution of Wolbachia in arthropods, but very few crustacean species are known to be infected. We investigated the prevalence of Wolbachia in 85 species from five crustacean orders. Twenty-two isopod species were found to carry these bacteria. The bacteria were found mainly in terrestrial species, suggesting that Wolbachia came from a continental environment. The evolutionary relationships between these Wolbachia strains were determined by sequencing bacterial genes and by interspecific transfers. All the bacteria associated with isopods belonged to the Wolbachia B group, based on 16S rDNA sequence data. All the terrestrial isopod symbionts in this group except one formed an independent clade. The results of interspecific transfers show evidence of specialization of Wolbachia symbionts to their isopod hosts. They also suggest that host species plays a more important role than bacterial phylogeny in determining the phenotype induced by Wolbachia infection. PMID:9684374

  2. Interaction of Wolbachia and Bloodmeal Type in Artificially Infected Aedes albopictus (Diptera: Culicidae)

    PubMed Central

    Suh, Eunho; Fu, Yuqing; Mercer, David R.; Dobson, Stephen L.

    2016-01-01

    Maternally inherited Wolbachia bacteria are being introduced into vector mosquito populations, with the goal of reducing the transmission of diseases such as dengue fever. The infection dynamics of Wolbachia depends upon the ability of Wolbachia to manipulate host reproduction as well as any fitness costs imposed upon the host. Some vector mosquito species are opportunistic blood feeders, utilizing both human and nonhuman vertebrate hosts, and the effects of bloodmeal source on Wolbachia phenotype is not well understood. Here we transfer wMelPop Wolbachia from Drosophila melanogaster (Meigen) into wild-type Aedes albopictus (Skuse) and characterize the resulting triple infection by examining for an effect of human and mouse blood on the Wolbachia infection persistence and phenotypes. When provided with human blood, the triple Wolbachia infection was persistent, with high maternal inheritance and relatively little fecundity cost, and a pattern of imperfect unidirectional cytoplasmic incompatibility was observed in mating experiments between wild-type and triply infected individuals. With mouse blood, reduced female fecundity and low maternal inheritance were observed in wMelPop-infected females, which affected the typical pattern of unidirectional CI. Our findings indicate the interactive effects of Wolbachia infection and blood source drive distinct shifts in the Wolbachia–host symbiotic association. PMID:27313167

  3. Using Wolbachia Releases to Estimate Aedes aegypti (Diptera: Culicidae) Population Size and Survival

    PubMed Central

    Garcia, Gabriela de Azambuja; dos Santos, Lilha Maria Barbosa; Villela, Daniel Antunes Maciel; Maciel-de-Freitas, Rafael

    2016-01-01

    Mosquitoes carrying the endosymbiont bacterium Wolbachia have been deployed in field trials as a biological control intervention due to Wolbachia effects on reducing transmission of arboviruses. We performed mark, release and recapture (MRR) experiments using Wolbachia as an internal marker with daily collections with BG-Traps during the first two weeks of releases in Rio de Janeiro, Brazil. The MRR design allowed us to investigate two critical parameters that determine whether Wolbachia would successful invade a field population: the probability of daily survival (PDS) of Wolbachia-infected Aedes aegypti females, and the wild population density during releases. Released females had a PDS of 0.82 and 0.89 in the first and second weeks, respectively, immediately after releases, which is well within the range of previous estimates of survivorship of wild mosquitoes in Rio de Janeiro. Abundance estimation of wild population varied up to 10-fold higher depending on the estimation method used (634–3565 females on the average-difference model to 6365–16188 females according to Lincoln-Petersen). Wolbachia-released mosquitoes were lower than the density estimation of their wild counterparts, irrespectively of the model used. Individually screening mosquitoes for the presence of Wolbachia reduced uncertainty on abundance estimations due to fluctuation in capturing per week. A successful invasion into local population requires Ae. aegypti fitness is unaffected by Wolbachia presence, but also reliable estimates on the population size of wild mosquitoes. PMID:27479050

  4. Multi-Infections of Feminizing Wolbachia Strains in Natural Populations of the Terrestrial Isopod Armadillidium Vulgare

    PubMed Central

    Valette, Victorien; Bitome Essono, Paul-Yannick; Le Clec’h, Winka; Johnson, Monique; Bech, Nicolas; Grandjean, Frédéric

    2013-01-01

    Maternally inherited Wolbachia (α-Proteobacteria) are widespread parasitic reproductive manipulators. A growing number of studies have described the presence of different Wolbachia strains within a same host. To date, no naturally occurring multiple infections have been recorded in terrestrial isopods. This is true for Armadillidium vulgare which is known to harbor non simultaneously three Wolbachia strains. Traditionally, such Wolbachia are detected by PCR amplification of the wsp gene and strains are characterized by sequencing. The presence of nucleotide deletions or insertions within the wsp gene, among these three different strains, provides the opportunity to test a novel genotyping method. Herein, we designed a new primer pair able to amplify products whose lengths are specific to each Wolbachia strain so as to detect the presence of multi-infections in A. vulgare. Experimental injections of Wolbachia strains in Wolbachia-free females were used to validate the methodology. We re-investigated, using this novel method, the infection status of 40 females sampled in 2003 and previously described as mono-infected based on the classical sequencing method. Among these females, 29 were identified as bi-infected. It is the first time that naturally occuring multiple infections of Wolbachia are detected within an individual A. vulgare host. Additionally, we resampled 6 of these populations in 2010 to check the infection status of females. PMID:24324814

  5. Influence of oxidative homeostasis on bacterial density and cost of infection in Drosophila-Wolbachia symbioses.

    PubMed

    Monnin, D; Kremer, N; Berny, C; Henri, H; Dumet, A; Voituron, Y; Desouhant, E; Vavre, F

    2016-06-01

    The evolution of symbioses along the continuum between parasitism and mutualism can be influenced by the oxidative homeostasis, that is the balance between reactive oxygen species (ROS) and antioxidant molecules. Indeed, ROS can contribute to the host immune defence to regulate symbiont populations, but are also toxic. This interplay between ROS and symbiosis is notably exemplified by recent results in arthropod-Wolbachia interactions. Wolbachia are symbiotic bacteria involved in a wide range of interactions with their arthropods hosts, from facultative, parasitic associations to obligatory, mutualistic ones. In this study, we used Drosophila-Wolbachia associations to determine whether the oxidative homeostasis plays a role in explaining the differences between phenotypically distinct arthropod-Wolbachia symbioses. We used Drosophila lines with different Wolbachia infections and measured the effects of pro-oxidant (paraquat) and antioxidant (glutathione) treatments on the Wolbachia density and the host survival. We show that experimental manipulations of the oxidative homeostasis can reduce the cost of the infection through its effect on Wolbachia density. We discuss the implication of this result from an evolutionary perspective and argue that the oxidative homeostasis could underlie the evolution of tolerance and dependence on Wolbachia. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  6. Effects of Wolbachia on mitochondrial DNA variation in populations of Athetis lepigone (Lepidoptera: Noctuidae) in China

    USDA-ARS?s Scientific Manuscript database

    Wolbachia are endosymbiotic bacteria that infect arthropods and incompatibility among strains can affect gene flow within host insect populations, that can result in significant host mitochondrial DNA (MtD) variation. The effects of Wolbachia infection on mtDNA variation was studied in Athetis lepi...

  7. Northern corn rootworm (Diabrotica barberi) populations infected by at least 5 Wolbachia strains

    USDA-ARS?s Scientific Manuscript database

    Wolbachia infections are present in northern corn rootworm (Diabrotica barberi) populations from east of the Mississippi River. The boundary between infected and uninfected populations is in central Illinois. DNA sequencing of Wolbachia ftsZ and wsp segments indicates that east central Illinois popu...

  8. Using Wolbachia Releases to Estimate Aedes aegypti (Diptera: Culicidae) Population Size and Survival.

    PubMed

    Garcia, Gabriela de Azambuja; Dos Santos, Lilha Maria Barbosa; Villela, Daniel Antunes Maciel; Maciel-de-Freitas, Rafael

    2016-01-01

    Mosquitoes carrying the endosymbiont bacterium Wolbachia have been deployed in field trials as a biological control intervention due to Wolbachia effects on reducing transmission of arboviruses. We performed mark, release and recapture (MRR) experiments using Wolbachia as an internal marker with daily collections with BG-Traps during the first two weeks of releases in Rio de Janeiro, Brazil. The MRR design allowed us to investigate two critical parameters that determine whether Wolbachia would successful invade a field population: the probability of daily survival (PDS) of Wolbachia-infected Aedes aegypti females, and the wild population density during releases. Released females had a PDS of 0.82 and 0.89 in the first and second weeks, respectively, immediately after releases, which is well within the range of previous estimates of survivorship of wild mosquitoes in Rio de Janeiro. Abundance estimation of wild population varied up to 10-fold higher depending on the estimation method used (634-3565 females on the average-difference model to 6365-16188 females according to Lincoln-Petersen). Wolbachia-released mosquitoes were lower than the density estimation of their wild counterparts, irrespectively of the model used. Individually screening mosquitoes for the presence of Wolbachia reduced uncertainty on abundance estimations due to fluctuation in capturing per week. A successful invasion into local population requires Ae. aegypti fitness is unaffected by Wolbachia presence, but also reliable estimates on the population size of wild mosquitoes.

  9. 100 Most Influential Publications in Scoliosis Surgery.

    PubMed

    Zhou, James Jun; Koltz, Michael T; Agarwal, Nitin; Tempel, Zachary J; Kanter, Adam S; Okonkwo, David O; Hamilton, D Kojo

    2017-03-01

    Bibliometric analysis. To apply the established technique of citation analysis to identify the 100 most influential articles in scoliosis surgery research published between 1900 and 2015. Previous studies have applied the technique of citation analysis to other areas of study. This is the first article to apply this technique to the field of scoliosis surgery. A two-step search of the Thomson Reuters Web of Science was conducted to identify all articles relevant to the field of scoliosis surgery. The top 100 articles with the most citations were identified based on analysis of titles and abstracts. Further statistical analysis was conducted to determine whether measures of author reputation and overall publication influence affected the rate at which publications were recognized and incorporated by other researchers in the field. Total citations for the final 100 publications included in the list ranged from 82 to 509. The period for publication ranged from 1954 to 2010. Most studies were published in the journal Spine (n = 63). The most frequently published topics of study were surgical techniques (n = 35) and outcomes (n = 35). Measures of author reputation (number of total studies in the top 100, number of first-author studies in the top 100) were found to have no effect on the rate at which studies were adopted by other researchers (number of years until first citation, and number of years until maximum citations). The number of citations/year a publication received was found to be negatively correlated with the rate at which it was adopted by other researchers, indicating that more influential manuscripts attained more rapid recognition by the scientific community at large. In assembling this publication, we have strived to identify and recognize the 100 most influential articles in scoliosis surgery research from 1900 to 2015. N/A.

  10. Significant heterogeneity in Wolbachia copy number within and between populations of Onchocerca volvulus.

    PubMed

    Armoo, Samuel; Doyle, Stephen R; Osei-Atweneboana, Mike Y; Grant, Warwick N

    2017-04-18

    Wolbachia are intracellular bacteria found in arthropods and several filarial nematode species. The filarial Wolbachia have been proposed to be involved in the immunopathology associated with onchocerciasis. Higher Wolbachia-to-nematode ratios have been reported in the savannah-ecotype compared to the forest-ecotype, and have been interpreted as consistent with a correlation between Wolbachia density and disease severity. However, factors such as geographic stratification and ivermectin drug exposure can lead to significant genetic heterogeneity in the nematode host populations, so we investigated whether Wolbachia copy number variation is also associated with these underlying factors. Genomic DNA was prepared from single adult nematodes representing forest and savannah ecotypes sampled from Togo, Ghana, Côte d'Ivoire and Mali. A qPCR assay was developed to measure the number of Wolbachia genome(s) per nematode genome. Next-generation sequencing (NGS) was also used to measure relative Wolbachia copy number, and independently verify the qPCR assay. Significant variation was observed within the forest (range: 0.02 to 452.99; median: 10.58) and savannah (range: 0.01 to 1106.25; median: 9.10) ecotypes, however, no significant difference between ecotypes (P = 0.645) was observed; rather, strongly significant Wolbachia variation was observed within and between the nine study communities analysed (P = 0.021), independent of ecotype. Analysis of ivermectin-treated and untreated nematodes by qPCR showed no correlation (P = 0.869); however, an additional analysis of a subset of the nematodes by qPCR and NGS revealed a correlation between response to ivermectin treatment and Wolbachia copy number (P = 0.020). This study demonstrates that extensive within and between population variation exists in the Wolbachia content of individual adult O. volvulus. The origin and functional significance of such variation (up to ~ 100,000-fold between worms; ~10 to 100

  11. The Gut Commensal Microbiome of Drosophila melanogaster Is Modified by the Endosymbiont Wolbachia

    PubMed Central

    Fast, Eva M.; Guo, Rong; Vaisman, Natalie; Ortiz, Luis; Bybee, Joanna; Slatko, Barton E.

    2017-01-01

    ABSTRACT Endosymbiotic Wolbachia bacteria and the gut microbiome have independently been shown to affect several aspects of insect biology, including reproduction, development, life span, stem cell activity, and resistance to human pathogens, in insect vectors. This work shows that Wolbachia bacteria, which reside mainly in the fly germline, affect the microbial species present in the fly gut in a lab-reared strain. Drosophila melanogaster hosts two main genera of commensal bacteria—Acetobacter and Lactobacillus. Wolbachia-infected flies have significantly reduced titers of Acetobacter. Sampling of the microbiome of axenic flies fed with equal proportions of both bacteria shows that the presence of Wolbachia bacteria is a significant determinant of the composition of the microbiome throughout fly development. However, this effect is host genotype dependent. To investigate the mechanism of microbiome modulation, the effect of Wolbachia bacteria on Imd and reactive oxygen species pathways, the main regulators of immune response in the fly gut, was measured. The presence of Wolbachia bacteria does not induce significant changes in the expression of the genes for the effector molecules in either pathway. Furthermore, microbiome modulation is not due to direct interaction between Wolbachia bacteria and gut microbes. Confocal analysis shows that Wolbachia bacteria are absent from the gut lumen. These results indicate that the mechanistic basis of the modulation of composition of the microbiome by Wolbachia bacteria is more complex than a direct bacterial interaction or the effect of Wolbachia bacteria on fly immunity. The findings reported here highlight the importance of considering the composition of the gut microbiome and host genetic background during Wolbachia-induced phenotypic studies and when formulating microbe-based disease vector control strategies. IMPORTANCE Wolbachia bacteria are intracellular bacteria present in the microbiome of a large fraction of

  12. Ensuring successful introduction of Wolbachia in natural populations of Aedes aegypti by means of feedback control.

    PubMed

    Bliman, Pierre-Alexandre; Aronna, M Soledad; Coelho, Flávio C; da Silva, Moacyr A H B

    2017-08-30

    The control of the spread of dengue fever by introduction of the intracellular parasitic bacterium Wolbachia in populations of the vector Aedes aegypti, is presently one of the most promising tools for eliminating dengue, in the absence of an efficient vaccine. The success of this operation requires locally careful planning to determine the adequate number of individuals carrying the Wolbachia parasite that need to be introduced into the natural population. The introduced mosquitoes are expected to eventually replace the Wolbachia-free population and guarantee permanent protection against the transmission of dengue to human. In this study, we propose and analyze a model describing the fundamental aspects of the competition between mosquitoes carrying Wolbachia and mosquitoes free of the parasite. We then use feedback control techniques to devise an introduction protocol that is proved to guarantee that the population converges to a stable equilibrium where the totality of mosquitoes carry Wolbachia.

  13. The wMel strain of Wolbachia Reduces Transmission of Zika virus by Aedes aegypti

    PubMed Central

    Aliota, Matthew T.; Peinado, Stephen A.; Velez, Ivan Dario; Osorio, Jorge E.

    2016-01-01

    Zika virus (ZIKV) is causing an explosive outbreak of febrile disease in the Americas. There are no effective antiviral therapies or licensed vaccines for this virus, and mosquito control strategies have not been adequate to contain the virus. A promising candidate for arbovirus control and prevention relies on the introduction of the intracellular bacterium Wolbachia into Aedes aegypti mosquitoes. This primarily has been proposed as a tool to control dengue virus (DENV) transmission; however, evidence suggests Wolbachia infections confer protection for Ae. aegypti against other arboviruses. At present, it is unknown whether or not ZIKV can infect, disseminate, and be transmitted by Wolbachia-infected Ae. aegypti. Using Ae. aegypti infected with the wMel strain of Wolbachia that are being released in Medellin, Colombia, we report that these mosquitoes have reduced vector competence for ZIKV. These results support the use of Wolbachia biocontrol as a multivalent strategy against Ae. aegypti-transmitted viruses. PMID:27364935

  14. Wolbachia infections in natural Anopheles populations affect egg laying and negatively correlate with Plasmodium development

    PubMed Central

    Shaw, W. Robert; Marcenac, Perrine; Childs, Lauren M.; Buckee, Caroline O.; Baldini, Francesco; Sawadogo, Simon P.; Dabiré, Roch K.; Diabaté, Abdoulaye; Catteruccia, Flaminia

    2016-01-01

    The maternally inherited alpha-proteobacterium Wolbachia has been proposed as a tool to block transmission of devastating mosquito-borne infectious diseases like dengue and malaria. Here we study the reproductive manipulations induced by a recently identified Wolbachia strain that stably infects natural mosquito populations of a major malaria vector, Anopheles coluzzii, in Burkina Faso. We determine that these infections significantly accelerate egg laying but do not induce cytoplasmic incompatibility or sex-ratio distortion, two parasitic reproductive phenotypes that facilitate the spread of other Wolbachia strains within insect hosts. Analysis of 221 blood-fed A. coluzzii females collected from houses shows a negative correlation between the presence of Plasmodium parasites and Wolbachia infection. A mathematical model incorporating these results predicts that infection with these endosymbionts may reduce malaria prevalence in human populations. These data suggest that Wolbachia may be an important player in malaria transmission dynamics in Sub-Saharan Africa. PMID:27243367

  15. Impacts of temperature and crowding on sex ratio, fecundity and Wolbachia infection intensity in the copepod, Mesocyclops thermocyclopoides.

    PubMed

    Wiwatanaratanabutr, Itsanun; Grandjean, Frederic

    2016-11-01

    Wolbachia are a group of intracellular bacteria that cause reproductive alterations in arthropods. Here, we describe the effects of two environmental factors (crowding and temperature) on phenotypic expression of feminization, the host's fecundity and Wolbachia infection intensity among life cycle stages in the naturally Wolbachia-infected copepod, Mesocyclops thermocyclopoides. The copepod was first found to be co-infected with Wolbachia A- and B-supergroups Wolbachia strains based on wsp primers. The relative Wolbachia infection intensity within individuals was determined using quantitative real-time PCR and was significantly higher in the B-supergroup than in the A-supergroup. Experimental results of temperature effect on bacterial density in each developmental stage revealed a significant decrease in Wolbachia infection intensity following exposure to high temperature (37°C) in both sexes and implied that Wolbachia might survive in room temperature (25°C) better than in high temperature. Experimental results of crowding effects on Wolbachia infection intensity suggested a negative correlation between copepod nauplii and Wolbachia infection intensity. No effect of rearing temperature on the sex ratio was reported although the fecundity was significantly decreased by high temperature. The results showed that Wolbachia infection intensity to be correlated with crowding conditions and was decreased following exposure of elevated temperature. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Wolbachia Infection Dynamics in Tribolium confusum (Coleoptera: Tenebrionidae) and Their Effects on Host Mating Behavior and Reproduction.

    PubMed

    Ming, Qing-Lei; Shen, Jia-Fei; Cheng, Chao; Liu, Chan-Min; Feng, Zhao-Jun

    2015-06-01

    Wolbachia interact with their hosts in a broad variety of relationships that range from parasitism to mutualism. To improve the understanding of complex relationships between Wolbachia and host, we performed not only mating and crossing experiments to investigate effects of Wolbachia on mate choice, mating performance, and reproduction in the confused flour beetles Tribolium confusum (Jacquelin du Val), but also quantitative PCR to determine Wolbachia spatiotemporal infection density dynamics within beetles. Wolbachia induced strong cytoplasmic incompatibility, but had no effects on male mate choice and mating performance. Compared with Wolbachia-uninfected females, infected females had very high fecundity irrespective of male's infection status. Wolbachia infection densities in beetles were higher in eggs and adults and in the reproductive tissues and abdomens, whereas Wolbachia density in adults did not differ between sexes and among different ages. These results suggest that Wolbachia have evolved mutualistic interactions with T. confusum, which provides the first evidence of Wolbachia mutualisms in this beetle species. We discussed these findings and their evolutionary implications in light of Wolbachia-host interactions. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Host tissues as microhabitats for Wolbachia and quantitative insights into the bacterial community in terrestrial isopods.

    PubMed

    Dittmer, J; Beltran-Bech, S; Lesobre, J; Raimond, M; Johnson, M; Bouchon, D

    2014-05-01

    Animal-bacterial symbioses are highly dynamic in terms of multipartite interactions, both between the host and its symbionts as well as between the different bacteria constituting the symbiotic community. These interactions will be reflected by the titres of the individual bacterial taxa, for example via host regulation of bacterial loads or competition for resources between symbionts. Moreover, different host tissues represent heterogeneous microhabitats for bacteria, meaning that host-associated bacteria might establish tissue-specific bacterial communities. Wolbachia are widespread endosymbiotic bacteria, infecting a large number of arthropods and filarial nematodes. However, relatively little is known regarding direct interactions between Wolbachia and other bacteria. This study represents the first quantitative investigation of tissue-specific Wolbachia-microbiota interactions in the terrestrial isopod Armadillidium vulgare. To this end, we obtained a more complete picture of the Wolbachia distribution patterns across all major host tissues, integrating all three feminizing Wolbachia strains (wVulM, wVulC, wVulP) identified to date in this host. Interestingly, the different Wolbachia strains exhibited strain-specific tissue distribution patterns, with wVulM reaching lower titres in most tissues. These patterns were consistent across different host genetic backgrounds and might reflect different co-evolutionary histories between the Wolbachia strains and A. vulgare. Moreover, Wolbachia-infected females carried higher total bacterial loads in several, but not all, tissues, irrespective of the Wolbachia strain. Taken together, this quantitative approach indicates that Wolbachia is part of a potentially more diverse bacterial community, as exemplified by the presence of highly abundant bacterial taxa in the midgut caeca of several A. vulgare populations.

  18. Wolbachia infections in native and introduced populations of fire ants (Solenopsis spp.).

    PubMed

    Shoemaker, D D; Ross, K G; Keller, L; Vargo, E L; Werren, J H

    2000-12-01

    Wolbachia are cytoplasmically inherited bacteria that induce a variety of effects with fitness consequences on host arthropods, including cytoplasmic incompatibility, parthenogenesis, male-killing and feminization. We report here the presence of Wolbachia in native South American populations of the fire ant Solenopsis invicta, but the apparent absence of the bacteria in introduced populations of this pest species in the USA. The Wolbachia strains in native S. invicta are of two divergent types (A and B), and the frequency of infection varies dramatically between geographical regions and social forms of this host. Survey data reveal that Wolbachia also are found in other native fire ant species within the Solenopsis saevissima species complex from South America, including S. richteri. This latter species also has been introduced in the USA, where it lacks Wolbachia. Sequence data reveal complete phylogenetic concordance between mtDNA haplotype in S. invicta and Wolbachia infection type (A or B). In addition, the mtDNA and associated group A Wolbachia strain in S. invicta are more closely related to the mtDNA and Wolbachia strain found in S. richteri than they are to the mtDNA and associated group B Wolbachia in S. invicta. These data are consistent with historical introgression of S. richteri cytoplasmic elements into S. invicta populations, resulting in enhanced infection and mtDNA polymorphisms in S. invicta. Wolbachia may have significant fitness effects on these hosts (either directly or by cytoplasmic incompatibility) and therefore these microbes potentially could be used in biological control programmes to suppress introduced fire ant populations.

  19. Onchocerca armillata contains the endosymbiotic bacterium Wolbachia and elicits a limited inflammatory response

    PubMed Central

    Neary, Joseph M.; Trees, Alexander J.; Ekale, David D.; Tanya, Vincent N.; Hetzel, Udo; Makepeace, Benjamin L.

    2010-01-01

    Human onchocerciasis, also known as River Blindness, is a debilitating disease caused by the filarial nematode Onchocerca volvulus. Many, but not all, filarial nematodes carry within their tissues endosymbiotic, Rickettsia-like bacteria of the genus Wolbachia. Onchocerca spp. infections in cattle offer the most relevant, analogous host–parasite model system. West African cattle are commonly co-infected with four Onchocerca spp.; two of these are Wolbachia-positive (Onchocerca gutturosa and Onchocerca ochengi), and the remainder are of unknown Wolbachia status (Onchocerca dukei and Onchocerca armillata). Previous studies have suggested that worm survival is dependent on this bacterium. O. armillata, an abundant parasite of African cattle that has received little attention, is a primitive species that may lack Wolbachia. The objectives of this study were to determine if O. armillata carries Wolbachia and to provide preliminary descriptions of the host inflammatory cell environment around the adult worms. The findings may support or refute the hypothesis that a prime contribution of Wolbachia is to permit long-term survival and reproduction of certain Onchocerca spp. (including O. volvulus in humans). O. armillata adult worms were found in the aorta of 90.7% of cattle (n = 54) slaughtered at an abattoir in Ngaoundéré, Adamawa Region, Cameroon. The presence of Wolbachia in O. armillata was confirmed by a specific anti-Wolbachia surface protein antibody detected using a peroxidase conjugate (immunohistochemistry) and PCR for detection of Wolbachia-specific sequences within DNA extracts from frozen worms. Tissue sections stained with haematoxylin and eosin showed the host cell response to be dominated by macrophages and fibroblasts. This is unusual compared with nodule-dwelling Wolbachia-positive Onchocerca spp., where the host response is typically characterised by granulocytes, and suggests that the mechanisms for worm survival employed by this species (which is

  20. The Mutualistic Side of Wolbachia–Isopod Interactions: Wolbachia Mediated Protection Against Pathogenic Intracellular Bacteria

    PubMed Central

    Braquart-Varnier, Christine; Altinli, Mine; Pigeault, Romain; Chevalier, Frédéric D.; Grève, Pierre; Bouchon, Didier; Sicard, Mathieu

    2015-01-01

    Wolbachia is a vertically transmitted endosymbiont whose radiative success is mainly related to various host reproductive manipulations that led to consider this symbiont as a conflictual reproductive parasite. However, lately, some Wolbachia have been shown to act as beneficial symbionts by protecting hosts against a broad range of parasites. Still, this protection has been mostly demonstrated in artificial Wolbachia-host associations between partners that did not co-evolved together. Here, we tested in two terrestrial isopod species Armadillidium vulgare and Porcellio dilatatus whether resident Wolbachia (native or non-native) could confer protection during infections with Listeria ivanovii and Salmonella typhimurium and also during a transinfection with a Wolbachia strain that kills the recipient host (i.e., wVulC in P. dilatatus). Survival analyses showed that (i) A. vulgare lines hosting their native Wolbachia (wVulC) always exhibited higher survival than asymbiotic ones when infected with pathogenic bacteria (ii) P. dilatatus lines hosting their native wDil Wolbachia strain survived the S. typhimurium infection better, while lines hosting non-native wCon Wolbachia strain survived the L. ivanovii and also the transinfection with wVulC from A. vulgare better. By studying L. ivanovii and S. typhimurium loads in the hemolymph of the different host-Wolbachia systems, we showed that (i) the difference in survival between lines after L. ivanovii infections were not linked to the difference between their pathogenic bacterial loads, and (ii) the difference in survival after S. typhimurium infections corresponds to lower loads of pathogenic bacteria. Overall, our results demonstrate a beneficial effect of Wolbachia on survival of terrestrial isopods when infected with pathogenic intracellular bacteria. This protective effect may rely on different mechanisms depending on the resident symbiont and the invasive bacteria interacting together within the hosts. PMID:26733946

  1. Glucose and Glycogen Metabolism in Brugia malayi Is Associated with Wolbachia Symbiont Fitness

    PubMed Central

    Voronin, Denis; Bachu, Saheed; Shlossman, Michael; Unnasch, Thomas R.; Ghedin, Elodie; Lustigman, Sara

    2016-01-01

    Wolbachia are endosymbiotic bacteria found in the majority of arthropods and filarial nematodes of medical and veterinary importance. They have evolved a wide range of symbiotic associations. In filarial nematodes that cause human lymphatic filariasis (Wuchereria bancrofti, Brugia malayi) or onchocerciasis (Onchocerca volvulus), Wolbachia are important for parasite development, reproduction and survival. The symbiotic bacteria rely in part on nutrients and energy sources provided by the host. Genomic analyses suggest that the strain of Wolbachia found in B. malayi (wBm) lacks the genes for two glycolytic enzymes—6-phosphofructokinase and pyruvate kinase—and is thus potentially unable to convert glucose into pyruvate, an important substrate for energy generation. The Wolbachia surface protein, wBm00432, is complexed to six B. malayi glycolytic enzymes, including aldolase. In this study we characterized two B. malayi aldolase isozymes and found that their expression is dependent on Wolbachia fitness and number. We confirmed by immuno-transmission electron microscopy that aldolase is associated with the Wolbachia surface. RNAi experiments suggested that aldolase-2 plays a significant role in both Wolbachia survival and embryogenesis in B. malayi. Treatment with doxycycline reduced Wolbachia fitness and increased the amount of both glucose and glycogen detected in the filarial parasite, indicating that glucose metabolism and glycogen storage in B. malayi are associated with Wolbachia fitness. This metabolic co-dependency between Wolbachia and its filarial nematode indicates that glycolysis could be a shared metabolic pathway between the bacteria and B. malayi, and thus a potential new target for anti-filarial therapy. PMID:27078260

  2. Onchocerca armillata contains the endosymbiotic bacterium Wolbachia and elicits a limited inflammatory response.

    PubMed

    Neary, Joseph M; Trees, Alexander J; Ekale, David D; Tanya, Vincent N; Hetzel, Udo; Makepeace, Benjamin L

    2010-12-15

    Human onchocerciasis, also known as River Blindness, is a debilitating disease caused by the filarial nematode Onchocerca volvulus. Many, but not all, filarial nematodes carry within their tissues endosymbiotic, Rickettsia-like bacteria of the genus Wolbachia. Onchocerca spp. infections in cattle offer the most relevant, analogous host-parasite model system. West African cattle are commonly co-infected with four Onchocerca spp.; two of these are Wolbachia-positive (Onchocerca gutturosa and Onchocerca ochengi), and the remainder are of unknown Wolbachia status (Onchocerca dukei and Onchocerca armillata). Previous studies have suggested that worm survival is dependent on this bacterium. O. armillata, an abundant parasite of African cattle that has received little attention, is a primitive species that may lack Wolbachia. The objectives of this study were to determine if O. armillata carries Wolbachia and to provide preliminary descriptions of the host inflammatory cell environment around the adult worms. The findings may support or refute the hypothesis that a prime contribution of Wolbachia is to permit long-term survival and reproduction of certain Onchocerca spp. (including O. volvulus in humans). O. armillata adult worms were found in the aorta of 90.7% of cattle (n=54) slaughtered at an abattoir in Ngaoundéré, Adamawa Region, Cameroon. The presence of Wolbachia in O. armillata was confirmed by a specific anti-Wolbachia surface protein antibody detected using a peroxidase conjugate (immunohistochemistry) and PCR for detection of Wolbachia-specific sequences within DNA extracts from frozen worms. Tissue sections stained with haematoxylin and eosin showed the host cell response to be dominated by macrophages and fibroblasts. This is unusual compared with nodule-dwelling Wolbachia-positive Onchocerca spp., where the host response is typically characterised by granulocytes, and suggests that the mechanisms for worm survival employed by this species (which is

  3. Effect of repeat human blood feeding on Wolbachia density and dengue virus infection in Aedes aegypti.

    PubMed

    Amuzu, Hilaria E; Simmons, Cameron P; McGraw, Elizabeth A

    2015-04-24

    The introduction of the endosymbiotic bacterium, Wolbachia into Aedes aegypti populations is a novel approach to reduce disease transmission. The presence of Wolbachia limits the ability of the mosquito to transmit dengue virus (DENV) and the strength of this effect appears to correlate with Wolbachia densities in the mosquito. There is also some evidence that Wolbachia densities may increase following the consumption of a bloodmeal. Here we have examined whether multiple blood feeds lead to increases in density or associated changes in Wolbachia-mediated blocking of DENV. The Wolbachia infected Aedes aegypti mosquito line was used for the study. There were three treatment groups; a non-blood fed control, a second group fed once and a third group fed twice on human blood. All groups were orally infected with DENV-2 and then their midguts and salivary glands were dissected 10-11 days post infection. RNA/DNA was simultaneously extracted from each tissue and subsequently used for DENV RNA copies and Wolbachia density quantification, respectively. We found variation between replicate vector competence experiments and no clear evidence that Wolbachia numbers increased in either the salivary glands or remainder of the body with feeding and hence saw no corresponding improvements in DENV blocking. Aedes aegypti are "sip" feeders returning often to obtain bloodmeals and hence it is important to assess whether repeat blood feeding improved the efficacy of Wolbachia-based DENV blocking. Our work suggests in the laboratory context when Wolbachia densities are high that repeat feeding does not improve blocking and hence this ability should likely be stable with respect to feeding cycle in the field.

  4. The Endosymbiotic Bacterium Wolbachia Selectively Kills Male Hosts by Targeting the Masculinizing Gene.

    PubMed

    Fukui, Takahiro; Kawamoto, Munetaka; Shoji, Keisuke; Kiuchi, Takashi; Sugano, Sumio; Shimada, Toru; Suzuki, Yutaka; Katsuma, Susumu

    2015-07-01

    Pathogens are known to manipulate the reproduction and development of their hosts for their own benefit. Wolbachia is an endosymbiotic bacterium that infects a wide range of insect species. Wolbachia is known as an example of a parasite that manipulates the sex of its host's progeny. Infection of Ostrinia moths by Wolbachia causes the production of all-female progeny, however, the mechanism of how Wolbachia accomplishes this male-specific killing is unknown. Here we show for the first time that Wolbachia targets the host masculinizing gene of Ostrinia to accomplish male-killing. We found that Wolbachia-infected O. furnacalis embryos do not express the male-specific splice variant of doublesex, a gene which acts at the downstream end of the sex differentiation cascade, throughout embryonic development. Transcriptome analysis revealed that Wolbachia infection markedly reduces the mRNA level of Masc, a gene that encodes a protein required for both masculinization and dosage compensation in the silkworm Bombyx mori. Detailed bioinformatic analysis also elucidated that dosage compensation of Z-linked genes fails in Wolbachia-infected O. furnacalis embryos, a phenomenon that is extremely similar to that observed in Masc mRNA-depleted male embryos of B. mori. Finally, injection of in vitro transcribed Masc cRNA into Wolbachia-infected embryos rescued male progeny. Our results show that Wolbachia-induced male-killing is caused by a failure of dosage compensation via repression of the host masculinizing gene. Our study also shows a novel strategy by which a pathogen hijacks the host sex determination cascade.

  5. Native Wolbachia from Aedes albopictus Blocks Chikungunya Virus Infection In Cellulo.

    PubMed

    Raquin, Vincent; Valiente Moro, Claire; Saucereau, Yoann; Tran, Florence-Hélène; Potier, Patrick; Mavingui, Patrick

    2015-01-01

    Wolbachia, a widespread endosymbiont of terrestrial arthropods, can protect its host against viral and parasitic infections, a phenotype called "pathogen blocking". However, in some cases Wolbachia may have no effect or even enhance pathogen infection, depending on the host-Wolbachia-pathogen combination. The tiger mosquito Aedes albopictus is naturally infected by two strains of Wolbachia, wAlbA and wAlbB, and is a competent vector for different arboviruses such as dengue virus (DENV) and chikungunya virus (CHIKV). Interestingly, it was shown in some cases that Ae. albopictus native Wolbachia strains are able to inhibit DENV transmission by limiting viral replication in salivary glands, but no such impact was measured on CHIKV replication in vivo. To better understand the Wolbachia/CHIKV/Ae. albopictus interaction, we generated a cellular model using Ae. albopictus derived C6/36 cells that we infected with the wAlbB strain. Our results indicate that CHIKV infection is negatively impacted at both RNA replication and virus assembly/secretion steps in presence of wAlbB. Using FISH, we observed CHIKV and wAlbB in the same mosquito cells, indicating that the virus is still able to enter the cell in the presence of the bacterium. Further work is needed to decipher molecular pathways involved in Wolbachia-CHIKV interaction at the cellular level, but this cellular model can be a useful tool to study the mechanism behind virus blocking phenotype induced by Wolbachia. More broadly, this put into question the ecological role of Wolbachia symbiont in Ae. albopictus, but also the ability of the CHIKV to counteract Wolbachia's antiviral potential in vivo.

  6. Glucose and Glycogen Metabolism in Brugia malayi Is Associated with Wolbachia Symbiont Fitness.

    PubMed

    Voronin, Denis; Bachu, Saheed; Shlossman, Michael; Unnasch, Thomas R; Ghedin, Elodie; Lustigman, Sara

    2016-01-01

    Wolbachia are endosymbiotic bacteria found in the majority of arthropods and filarial nematodes of medical and veterinary importance. They have evolved a wide range of symbiotic associations. In filarial nematodes that cause human lymphatic filariasis (Wuchereria bancrofti, Brugia malayi) or onchocerciasis (Onchocerca volvulus), Wolbachia are important for parasite development, reproduction and survival. The symbiotic bacteria rely in part on nutrients and energy sources provided by the host. Genomic analyses suggest that the strain of Wolbachia found in B. malayi (wBm) lacks the genes for two glycolytic enzymes--6-phosphofructokinase and pyruvate kinase--and is thus potentially unable to convert glucose into pyruvate, an important substrate for energy generation. The Wolbachia surface protein, wBm00432, is complexed to six B. malayi glycolytic enzymes, including aldolase. In this study we characterized two B. malayi aldolase isozymes and found that their expression is dependent on Wolbachia fitness and number. We confirmed by immuno-transmission electron microscopy that aldolase is associated with the Wolbachia surface. RNAi experiments suggested that aldolase-2 plays a significant role in both Wolbachia survival and embryogenesis in B. malayi. Treatment with doxycycline reduced Wolbachia fitness and increased the amount of both glucose and glycogen detected in the filarial parasite, indicating that glucose metabolism and glycogen storage in B. malayi are associated with Wolbachia fitness. This metabolic co-dependency between Wolbachia and its filarial nematode indicates that glycolysis could be a shared metabolic pathway between the bacteria and B. malayi, and thus a potential new target for anti-filarial therapy.

  7. Model of aircraft passenger acceptance

    NASA Technical Reports Server (NTRS)

    Jacobson, I. D.

    1978-01-01

    A technique developed to evaluate the passenger response to a transportation system environment is described. Reactions to motion, noise, temperature, seating, ventilation, sudden jolts and descents are modeled. Statistics are presented for the age, sex, occupation, and income distributions of the candidates analyzed. Values are noted for the relative importance of system variables such as time savings, on-time arrival, convenience, comfort, safety, the ability to read and write, and onboard services.

  8. Model of aircraft passenger acceptance

    NASA Technical Reports Server (NTRS)

    Jacobson, I. D.

    1978-01-01

    A technique developed to evaluate the passenger response to a transportation system environment is described. Reactions to motion, noise, temperature, seating, ventilation, sudden jolts and descents are modeled. Statistics are presented for the age, sex, occupation, and income distributions of the candidates analyzed. Values are noted for the relative importance of system variables such as time savings, on-time arrival, convenience, comfort, safety, the ability to read and write, and onboard services.

  9. Regulation of arginine methyltransferase 3 by a Wolbachia-induced microRNA in Aedes aegypti and its effect on Wolbachia and dengue virus replication.

    PubMed

    Zhang, Guangmei; Hussain, Mazhar; Asgari, Sassan

    2014-10-01

    The gram-negative endosymbiotic bacteria, Wolbachia, have been found to colonize a wide range of invertebrates, including over 40% of insect species. Best known for host reproductive manipulations, some strains of Wolbachia have been shown to reduce the host life span by about 50% and inhibit replication and transmission of dengue virus (DENV) in the mosquito vector, Aedes aegypti. The molecular mechanisms underlying these effects still are not well understood. Our previous studies showed that Wolbachia uses host microRNAs (miRNAs) to manipulate host gene expression for its efficient maintenance and limiting replication of DENV in Ae. aegypti. Protein arginine methyltransferases are structurally and functionally conserved proteins from yeast to human. In mammals, it has been reported that protein arginine methyltransferases such as PRMT1, 5 and 6 could regulate replication of different viruses. Ae. aegypti contains eight members of protein arginine methyltransferases (AaArgM1-8). Here, we show that the wMelPop strain of Wolbachia introduced into Ae. aegypti significantly induces the expression of AaArgM3. Interestingly, we found that Wolbachia uses aae-miR-2940, which is highly upregulated in Wolbachia-infected mosquitoes, to upregulate the expression of AaArgM3. Silencing of AaArgM3 in a mosquito cell line led to a significant reduction in Wolbachia replication, but had no effect on the replication of DENV. These results provide further evidence that Wolbachia uses the host miRNAs to manipulate host gene expression and facilitate colonization in Ae. aegypti mosquito.

  10. Wolbachia in the Flesh: Symbiont Intensities in Germ-Line and Somatic Tissues Challenge the Conventional View of Wolbachia Transmission Routes

    PubMed Central

    Frost, Crystal L.; Pollock, Steven W.; Smith, Judith E.; Hughes, William O. H.

    2014-01-01

    Symbionts can substantially affect the evolution and ecology of their hosts. The investigation of the tissue-specific distribution of symbionts (tissue tropism) can provide important insight into host-symbiont interactions. Among other things, it can help to discern the importance of specific transmission routes and potential phenotypic effects. The intracellular bacterial symbiont Wolbachia has been described as the greatest ever panzootic, due to the wide array of arthropods that it infects. Being primarily vertically transmitted, it is expected that the transmission of Wolbachia would be enhanced by focusing infection in the reproductive tissues. In social insect hosts, this tropism would logically extend to reproductive rather than sterile castes, since the latter constitute a dead-end for vertically transmission. Here, we show that Wolbachia are not focused on reproductive tissues of eusocial insects, and that non-reproductive tissues of queens and workers of the ant Acromyrmex echinatior, harbour substantial infections. In particular, the comparatively high intensities of Wolbachia in the haemolymph, fat body, and faeces, suggest potential for horizontal transmission via parasitoids and the faecal-oral route, or a role for Wolbachia modulating the immune response of this host. It may be that somatic tissues and castes are not the evolutionary dead-end for Wolbachia that is commonly thought. PMID:24988478

  11. Wolbachia in the flesh: symbiont intensities in germ-line and somatic tissues challenge the conventional view of Wolbachia transmission routes.

    PubMed

    Frost, Crystal L; Pollock, Steven W; Smith, Judith E; Hughes, William O H

    2014-01-01

    Symbionts can substantially affect the evolution and ecology of their hosts. The investigation of the tissue-specific distribution of symbionts (tissue tropism) can provide important insight into host-symbiont interactions. Among other things, it can help to discern the importance of specific transmission routes and potential phenotypic effects. The intracellular bacterial symbiont Wolbachia has been described as the greatest ever panzootic, due to the wide array of arthropods that it infects. Being primarily vertically transmitted, it is expected that the transmission of Wolbachia would be enhanced by focusing infection in the reproductive tissues. In social insect hosts, this tropism would logically extend to reproductive rather than sterile castes, since the latter constitute a dead-end for vertically transmission. Here, we show that Wolbachia are not focused on reproductive tissues of eusocial insects, and that non-reproductive tissues of queens and workers of the ant Acromyrmex echinatior, harbour substantial infections. In particular, the comparatively high intensities of Wolbachia in the haemolymph, fat body, and faeces, suggest potential for horizontal transmission via parasitoids and the faecal-oral route, or a role for Wolbachia modulating the immune response of this host. It may be that somatic tissues and castes are not the evolutionary dead-end for Wolbachia that is commonly thought.

  12. Wolbachia density and cytoplasmic incompatibility in Aedes albopictus: concerns with using artificial Wolbachia infection as a vector suppression tool.

    PubMed

    Calvitti, Maurizio; Marini, Francesca; Desiderio, Angiola; Puggioli, Arianna; Moretti, Riccardo

    2015-01-01

    The mosquito Aedes albopictusi is a competent vector of harmful human pathogens, including viruses causing dengue and chikungunya. Cytoplasmic incompatibility (CI) induced by endosymbiotic Wolbachia can be used to produce functionally sterile males that can be released in the field as a suppression tool against this mosquito. Because the available sexing methods are not efficient enough to avoid unintentional release of a few transinfected females, we assessed the CI pattern in crosses between wPip Wolbachia-transinfected (ARwP) females and wild-type males of Ae. albopictus in this study. Quantitative polymerase chain reaction was used to monitor the titer of the Wolbachia strains that naturally infect Ae. albopictus, that is, wAlbA and wAlbB, in age-controlled males and females. Data were coupled with incompatibility level detected when the above-mentioned males were crossed with ARwP females. Wolbachia infection titer was also monitored in samples of wild caught males. Incompatibility level was positively correlated only with wAlbA density. Crosses between wild-type males having very low wAlbA density (<0.001 wAlbA/actin copy numbers) and ARwP females were partially fertile (CIcorr = 68.06 ± 6.20). Individuals with low wAlbA titer were frequently found among sampled wild males (30%-50% depending on the site and period). ARwP males can be as considered as a very promising tool for suppressing Ae. albopictus. However, crosses between wild males having low wAlbA density and ARwP females may be partially fertile. In the case of local establishment of the transinfected mosquito line, this occurrence may favor the replacement of the wild-type mosquitoes with the ARwP line, thus reducing the long-term efficacy of incompatible insect technique. Various alternative strategies have been discussed to prevent this risk and to exploit Wolbachia as a tool to control Ae. albopictus.

  13. Wolbachia Density and Cytoplasmic Incompatibility in Aedes albopictus: Concerns with Using Artificial Wolbachia Infection as a Vector Suppression Tool

    PubMed Central

    Calvitti, Maurizio; Marini, Francesca; Desiderio, Angiola; Puggioli, Arianna; Moretti, Riccardo

    2015-01-01

    The mosquito Aedes albopictusi is a competent vector of harmful human pathogens, including viruses causing dengue and chikungunya. Cytoplasmic incompatibility (CI) induced by endosymbiotic Wolbachia can be used to produce functionally sterile males that can be released in the field as a suppression tool against this mosquito. Because the available sexing methods are not efficient enough to avoid unintentional release of a few transinfected females, we assessed the CI pattern in crosses between wPip Wolbachia-transinfected (ARwP) females and wild-type males of Ae. albopictus in this study. Quantitative polymerase chain reaction was used to monitor the titer of the Wolbachia strains that naturally infect Ae. albopictus, that is, wAlbA and wAlbB, in age-controlled males and females. Data were coupled with incompatibility level detected when the above-mentioned males were crossed with ARwP females. Wolbachia infection titer was also monitored in samples of wild caught males. Incompatibility level was positively correlated only with wAlbA density. Crosses between wild-type males having very low wAlbA density (<0.001 wAlbA/actin copy numbers) and ARwP females were partially fertile (CIcorr = 68.06 ± 6.20). Individuals with low wAlbA titer were frequently found among sampled wild males (30%–50% depending on the site and period). ARwP males can be as considered as a very promising tool for suppressing Ae. albopictus. However, crosses between wild males having low wAlbA density and ARwP females may be partially fertile. In the case of local establishment of the transinfected mosquito line, this occurrence may favor the replacement of the wild-type mosquitoes with the ARwP line, thus reducing the long-term efficacy of incompatible insect technique. Various alternative strategies have been discussed to prevent this risk and to exploit Wolbachia as a tool to control Ae. albopictus. PMID:25812130

  14. Wolbachia-induced paternal defect in Drosophila is likely by interaction with the juvenile hormone pathway.

    PubMed

    Liu, Chen; Wang, Jia-Lin; Zheng, Ya; Xiong, En-Juan; Li, Jing-Jing; Yuan, Lin-Ling; Yu, Xiao-Qiang; Wang, Yu-Feng

    2014-06-01

    Wolbachia are endosymbionts that infect many insect species. They can manipulate the host's reproduction to increase their own maternal transmission. Cytoplasmic incompatibility (CI) is one such manipulation, which is expressed as embryonic lethality when Wolbachia-infected males mate with uninfected females. However, matings between males and females carrying the same Wolbachia strain result in viable progeny. The molecular mechanisms of CI are currently not clear. We have previously reported that the gene Juvenile hormone-inducible protein 26 (JhI-26) exhibited the highest upregulation in the 3rd instar larval testes of Drosophila melanogaster when infected by Wolbachia. This is reminiscent of an interaction between Wolbachia and juvenile hormone (JH) pathway in flies. Considering that Jhamt gene encodes JH acid methyltransferase, a key regulatory enzyme of JH biosynthesis, and that methoprene-tolerant (Met) has been regarded as the best JH receptor candidate, we first compared the expression of Jhamt and Met between Wolbachia-infected and uninfected fly testes to investigate whether Wolbachia infection influence the JH signaling pathway. We found that the expressions of Jhamt and Met were significantly increased in the presence of Wolbachia, suggesting an interaction of Wolbachia with the JH signaling pathway. Then, we found that overexpression of JhI-26 in Wolbachia-free transgenic male flies caused paternal-effect lethality that mimics the defects associated with CI. JhI-26 overexpressing males resulted in significantly decrease in hatch rate. Surprisingly, Wolbachia-infected females could rescue the egg hatch. In addition, we showed that overexpression of JhI-26 caused upregulation of the male accessory gland protein (Acp) gene CG10433, but not vice versa. This result suggests that JhI-26 may function at the upstream of CG10433. Likewise, overexpression of CG10433 also resulted in paternal-effect lethality. Both JhI-26 and CG10433 overexpressing males

  15. Variable Inhibition of Zika Virus Replication by Different Wolbachia Strains in Mosquito Cell Cultures.

    PubMed

    Schultz, Michaela J; Isern, Sharon; Michael, Scott F; Corley, Ronald B; Connor, John H; Frydman, Horacio M

    2017-07-15

    Mosquito-borne arboviruses are a major source of human disease. One strategy to reduce arbovirus disease is to reduce the mosquito's ability to transmit virus. Mosquito infection with the bacterial endosymbiont Wolbachia pipientis wMel is a novel strategy to reduce Aedes mosquito competency for flavivirus infection. However, experiments investigating cyclic environmental temperatures have shown a reduction in maternal transmission of wMel, potentially weakening the integration of this strain into a mosquito population relative to that of other Wolbachia strains. Consequently, it is important to investigate additional Wolbachia strains. All Zika virus (ZIKV) suppression studies are limited to the wMel Wolbachia strain. Here we show ZIKV inhibition by two different Wolbachia strains: wAlbB (isolated from Aedes albopictus mosquitoes) and wStri (isolated from the planthopper Laodelphax striatellus) in mosquito cells. Wolbachia strain wStri inhibited ZIKV most effectively. Single-cycle infection experiments showed that ZIKV RNA replication and nonstructural protein 5 translation were reduced below the limits of detection in wStri-containing cells, demonstrating early inhibition of virus replication. ZIKV replication was rescued when Wolbachia was inhibited with a bacteriostatic antibiotic. We observed a partial rescue of ZIKV growth when Wolbachia-infected cells were supplemented with cholesterol-lipid concentrate, suggesting competition for nutrients as one of the possible mechanisms of Wolbachia inhibition of ZIKV. Our data show that wAlbB and wStri infection causes inhibition of ZIKV, making them attractive candidates for further in vitro mechanistic and in vivo studies and future vector-centered approaches to limit ZIKV infection and spread.IMPORTANCE Zika virus (ZIKV) has swiftly spread throughout most of the Western Hemisphere. This is due in large part to its replication in and spread by a mosquito vector host. There is an urgent need for approaches that limit

  16. Absence of influential spreaders in rumor dynamics

    NASA Astrophysics Data System (ADS)

    Borge-Holthoefer, Javier; Moreno, Yamir

    2012-02-01

    Recent research [Kitsak, Gallos, Havlin, Liljeros, Muchnik, Stanley, and Makse, Nature Physics1745-247310.1038/nphys1746 6, 888 (2010)] has suggested that coreness, and not degree, constitutes a better topological descriptor to identify influential spreaders in complex networks. This hypothesis has been verified in the context of disease spreading. Here, we instead focus on rumor spreading models, which are more suited for social contagion and information propagation. To this end, we perform extensive computer simulations on top of several real-world networks and find opposite results. Namely, we show that the spreading capabilities of the nodes do not depend on their k-core index, which instead determines whether or not a given node prevents the diffusion of a rumor to a system-wide scale. Our findings are relevant both for sociological studies of contagious dynamics and for the design of efficient commercial viral processes.

  17. 46 CFR 122.515 - Passenger safety bill.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Passenger safety bill. 122.515 Section 122.515 Shipping... Emergencies § 122.515 Passenger safety bill. (a) A passenger safety bill must be posted by the master in each... accommodations for more than 49 passengers. (b) Each passenger safety bill required by this section must list:...

  18. 46 CFR 122.515 - Passenger safety bill.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Passenger safety bill. 122.515 Section 122.515 Shipping... Emergencies § 122.515 Passenger safety bill. (a) A passenger safety bill must be posted by the master in each... accommodations for more than 49 passengers. (b) Each passenger safety bill required by this section must list:...

  19. Helicopter crew/passenger vibration sensitivity -

    NASA Technical Reports Server (NTRS)

    Gabel, R.; Reed, D. A.

    1972-01-01

    Helicopter crew and passenger vibration sensitivity are presented. Pilot subjective ratings are established for discrete frequencies and the impact of combinations of harmonic frequencies is examined. A passenger long term comfort level and a short term limit are defined for discrete frequencies and compared with pilot ratings. The results show reasonable agreement between pilot and passenger. Subjective comfort levels obtained for mixed frequency environments clearly demonstrate the need for a multi-frequency criterion.

  20. The impacts of Wolbachia and the microbiome on mate choice in Drosophila melanogaster.

    PubMed

    Arbuthnott, D; Levin, T C; Promislow, D E L

    2016-02-01

    Symbionts and parasites can manipulate their hosts' reproduction to their own benefit, profoundly influencing patterns of mate choice and evolution of the host population. Wolbachia is one of the most widespread symbionts among arthropods, and one that alters its hosts' reproduction in diverse and dramatic ways. While we are beginning to appreciate how Wolbachia's extreme manipulations of host reproduction can influence species diversification and reproductive isolation, we understand little about how symbionts and Wolbachia, in particular, may affect intrapopulation processes of mate choice. We hypothesized that the maternally transmitted Wolbachia would increase the attractiveness of its female hosts to further its own spread. We therefore tested the effects of Wolbachia removal and microbiome disruption on female attractiveness and male mate choice among ten isofemale lines of Drosophila melanogaster. We found variable effects of general microbiome disruption on female attractiveness, with indications that bacteria interact with hosts in a line-specific manner to affect female attractiveness. However, we found no evidence that Wolbachia influence female attractiveness or male mate choice among these lines. Although the endosymbiont Wolbachia can greatly alter the reproduction of their hosts in many species, there is no indication that they alter mate choice behaviours in D. melanogaster.

  1. Wolbachia in guilds of Anastrepha fruit flies (Tephritidae) and parasitoid wasps (Braconidae)

    PubMed Central

    Mascarenhas, Rodrigo O; Prezotto, Leandro F; Perondini, André Luiz P; Marino, Celso Luiz; Selivon, Denise

    2016-01-01

    Abstract The endosymbiont Wolbachia is efficiently transmitted from females to their progenies, but horizontal transmission between different taxa is also known to occur. Aiming to determine if horizontal transmission might have occurred between Anastrepha fruit flies and associated braconid wasps, infection by Wolbachia was screened by amplification of a fragment of the wsp gene. Eight species of the genus Anastrepha were analyzed, from which six species of associated parasitoid wasps were recovered. The endosymbiont was found in seven Anastrepha species and in five species of braconids. The WSP Typing methodology detected eight wsp alleles belonging to Wolbachia supergroup A. Three were already known and five were new ones, among which four were found to be putative recombinant haplotypes. Two samples of Anastrepha obliqua and one sample of Doryctobracon brasiliensis showed multiple infection. Single infection by Wolbachia was found in the majority of samples. The distribution of Wolbachia harboring distinct alleles differed significantly between fruit flies and wasps. However, in nine samples of fruit flies and associated wasps, Wolbachia harbored the same wsp allele. These congruences suggest that horizontal transfer of Wolbachia might have occurred in the communities of fruit flies and their braconid parasitoids. PMID:27648768

  2. Heat Sensitivity of wMel Wolbachia during Aedes aegypti Development

    PubMed Central

    Beier, John C.; Devine, Gregor J.; Hugo, Leon E.

    2016-01-01

    The wMel strain of Wolbachia bacteria is known to prevent dengue and Zika virus transmission in the mosquito vector Aedes aegypti. Accordingly, the release of wMel-infected A. aegypti in endemic regions has been recommended by the World Health Organization as a potential strategy for controlling dengue and Zika outbreaks. However, the utility of this approach could be limited if high temperatures in the aquatic habitats where A. aegypti develop are detrimental to Wolbachia. We exposed wMel-infected A. aegypti eggs and larvae to fluctuating daily temperatures of 30–40°C for three, five, or seven days during their development. We found that Wolbachia levels in females emerging from heat treatments were significantly lower than in the controls that had developed at 20–30°C. Notably, seven days of high temperatures starting at the egg stage reduced Wolbachia levels in emerging females to less than 0.1% of the wMel control levels. However, after adult females returned to 20–30°C for 4–7 days, they experienced differing degrees of Wolbachia recovery. Our findings suggest that the spread of Wolbachia in wild A. aegypti populations and any consequent protection from dengue and Zika viruses might be limited in ecosystems that experience periods of extreme heat, but Wolbachia levels recover partially after temperatures return to normal. PMID:27459519

  3. Many compatible Wolbachia strains coexist within natural populations of Culex pipiens mosquito

    PubMed Central

    Duron, O; Raymond, M; Weill, M

    2011-01-01

    Maternally inherited Wolbachia often manipulate the reproduction of arthropods to promote their transmission. In most species, Wolbachia exert a form of conditional sterility termed cytoplasmic incompatibility (CI), characterized by the death of embryos produced by the mating between individuals with incompatible Wolbachia infections. From a theoretical perspective, no stable coexistence of incompatible Wolbachia infections is expected within host populations and CI should induce the invasion of one strain or of a set of compatible strains. In this study, we investigated this prediction on CI dynamics in natural populations of the common house mosquito Culex pipiens. We surveyed the Wolbachia diversity and the expression of CI in breeding sites of the south of France between 1990 and 2005. We found that geographically close C. pipiens populations harbor considerable Wolbachia diversity, which is stably maintained over 15 years. We also observed a very low frequency of infertile clutches within each sampled site. Meanwhile, mating choice experiments conducted in laboratory conditions showed that assortative mating does not occur. Overall, this suggests that a large set of compatible Wolbachia strains are always locally dominant within mosquito populations thus, fitting with the theoretical expectations on CI dynamics. PMID:21119702

  4. Onchocerciasis: the role of Wolbachia bacterial endosymbionts in parasite biology, disease pathogenesis, and treatment.

    PubMed

    Tamarozzi, Francesca; Halliday, Alice; Gentil, Katrin; Hoerauf, Achim; Pearlman, Eric; Taylor, Mark J

    2011-07-01

    The discovery of Wolbachia intracellular bacteria within filarial nematodes, including Onchocerca volvulus, the causative agent of onchocerciasis or "river blindness," has delivered a paradigm shift in our understanding of the parasite's biology, to where we now know that the bacterial endosymbionts are essential for normal development of larvae and embryos and may support the long-term survival of adult worms. The apparent mutualistic dependency has also offered a novel approach to the treatment of onchocerciasis through the use of antibiotics to eliminate Wolbachia, delivering for the first time a treatment which has significant macrofilaricidal efficacy. Studies with other filarial nematode species have also highlighted a role for Wolbachia in transmission and infection of the mammalian host through a fascinating manipulation of mast cell-mediated vasodilation to enhance infectivity of vector-borne larvae. Wolbachia has also been identified as the principal driver of innate and adaptive Th1 inflammatory immunity, which can either contribute to disease pathogenesis or, with the Wolbachia-mediated recruitment of mast cells, enhance infectivity. The Wolbachia activation of innate inflammation also drives inflammatory adverse events in response to chemotherapy with either diethylcarbamazine (DEC) or ivermectin. In this review we summarize the experimental and field trial data which have uncovered the importance of Wolbachia symbiosis in onchocerciasis.

  5. Wolbachia in guilds of Anastrepha fruit flies (Tephritidae) and parasitoid wasps (Braconidae).

    PubMed

    Mascarenhas, Rodrigo O; Prezotto, Leandro F; Perondini, André Luiz P; Marino, Celso Luiz; Selivon, Denise

    2016-01-01

    The endosymbiont Wolbachia is efficiently transmitted from females to their progenies, but horizontal transmission between different taxa is also known to occur. Aiming to determine if horizontal transmission might have occurred between Anastrepha fruit flies and associated braconid wasps, infection by Wolbachia was screened by amplification of a fragment of the wsp gene. Eight species of the genus Anastrepha were analyzed, from which six species of associated parasitoid wasps were recovered. The endosymbiont was found in seven Anastrepha species and in five species of braconids. The WSP Typing methodology detected eight wsp alleles belonging to Wolbachia supergroup A. Three were already known and five were new ones, among which four were found to be putative recombinant haplotypes. Two samples of Anastrepha obliqua and one sample of Doryctobracon brasiliensis showed multiple infection. Single infection by Wolbachia was found in the majority of samples. The distribution of Wolbachia harboring distinct alleles differed significantly between fruit flies and wasps. However, in nine samples of fruit flies and associated wasps, Wolbachia harbored the same wsp allele. These congruences suggest that horizontal transfer of Wolbachia might have occurred in the communities of fruit flies and their braconid parasitoids.

  6. Wolbachia strains in cryptic species of the Anastrepha fraterculus complex (Diptera, Tephritidae) along the Neotropical Region.

    PubMed

    Prezotto, Leandro F; Perondini, André L P; Hernández-Ortiz, Vicente; Marino, Celso L; Selivon, Denise

    2017-01-01

    Infection by Wolbachia was described previously in eleven species of Anastrepha fruit flies some of which are important pests of fruticulture. One such species is the nominal Anastrepha fraterculus, the South American fruit fly, which actually comprises a complex of cryptic species. The suggestions of using Wolbachia for the control of these pest species, make imperative a more precise characterization of the existing strains of the bacteria. In this study, population samples of the A. fraterculus complex from Brazil, Argentina, Peru, Ecuador, Colombia, Guatemala and Mexico were analyzed for Wolbachia infection. The bacteria were genotyped by the MLST and WSP Typing methodologies. All samples were infected with Wolbachia of supergroup "A". For each of the five MLST genes, unique as well as already known alleles were detected. Nineteen sequence types for the concatenated sequences of the five MLST genes, and twenty wsp alleles were found in the samples. Host-specific haplotypes, shared strains among distinct hosts, and more than one strain of Wolbachia were found in some population samples. Recombination among the MLST genes and intragenic recombination between wsp haplotypes was rare. Phylogenetic analysis showed a great similarity among the Wolbachia strains in the A. fraterculus complex. However, some strains of Wolbachia are found throughout the Neotropical Region and there are specific strains in determined geographical areas. Copyright © 2016 Elsevier GmbH. All rights reserved.

  7. Evidence for a new feminizing Wolbachia strain in the isopod Armadillidium vulgare: evolutionary implications.

    PubMed

    Cordaux, R; Michel-Salzat, A; Frelon-Raimond, M; Rigaud, T; Bouchon, D

    2004-07-01

    Wolbachia are intracellular maternally inherited alpha-Proteobacteria infecting a wide range of arthropods. In the common pill bug Armadillidium vulgare, the known Wolbachia strain is responsible for feminization of genetic males. We have investigated Wolbachia diversity in 20 populations of A. vulgare from west and east Europe, north Africa and north America. A new Wolbachia strain (wVulM) was identified through the variability of the wsp gene, distantly related to that previously known (wVulC) in this host species. No individual with multiple infections was detected. Inoculation experiments indicated that the new wVulM bacterial strain also induces feminization in A. vulgare. However, the wVulC strain showed a higher transmission rate than the wVulM strain and was the most geographically widespread Wolbachia in A. vulgare populations. Mitochondrial 16SrDNA gene sequencing was conducted in Wolbachia-infected individuals, revealing the occurrence of four host lineages. The comparison of bacterial strains and their respective host mitochondrial phylogenies failed to show concordance, indicating horizontal transmission of the Wolbachia strains within populations of A. vulgare.

  8. Molecular characterization of Wolbachia infection in bed bugs (Cimex lectularius) collected from several localities in France.

    PubMed

    Akhoundi, Mohammad; Cannet, Arnaud; Loubatier, Céline; Berenger, Jean-Michel; Izri, Arezki; Marty, Pierre; Delaunay, Pascal

    2016-01-01

    Wolbachia symbionts are maternally inherited intracellular bacteria that have been detected in numerous insects including bed bugs. The objective of this study, the first epidemiological study in Europe, was to screen Wolbachia infection among Cimex lectularius collected in the field, using PCR targeting the surface protein gene (wsp), and to compare obtained Wolbachia strains with those reported from laboratory colonies of C. lectularius as well as other Wolbachia groups. For this purpose, 284 bed bug specimens were caught and studied from eight different regions of France including the suburbs of Paris, Bouches-du-Rhône, Lot-et-Garonne, and five localities in Alpes-Maritimes. Among the samples, 166 were adults and the remaining 118 were considered nymphs. In all, 47 out of 118 nymphs (40%) and 61 out of 166 adults (37%) were found positive on wsp screening. Among the positive cases, 10 samples were selected randomly for sequencing. The sequences had 100% homology with wsp sequences belonging to the F-supergroup strains of Wolbachia. Therefore, we confirm the similarity of Wolbachia strains detected in this epidemiological study to Wolbachia spp. reported from laboratory colonies of C. lectularius.

  9. Molecular evidence for single Wolbachia infections among geographic strains of the flour beetle Tribolium confusum.

    PubMed Central

    Fialho, R F; Stevens, L

    1997-01-01

    Infections with the rickettsial microorganism Wolbachia are cytoplasmically inherited and occur in a wide range of insect species and several other arthropods. Wolbachia infection often results in unidirectional cytoplasmic incompatibility (CI): crosses between infected males and uninfected females are incompatible and show a reduction of progeny or complete inviability. Unidirectional CI can also occur when males harbouring two incompatible Wolbachia strains are crossed with females infected with only one of the two strains. In the flour beetle Tribolium confusum, Wolbachia infections are of particular interest because of the severity of incompatibility. Typically, no progeny results from the incompatible cross, whereas only partial incompatibility is observed in most other hosts. Werren et al. (1995a) reported that Wolbachia infections in T. confusum consist of two bacterial strains belonging to distinct phylogenic groups, based on PCR amplification and sequence analysis of the bacterial cell division gene ftsZ. However, Fialho & Stevens (1996) showed that eight strains of T. confusum were infected with a single and common incompatibility type. Here we report analysis of the ftsZ gene by specific PCR amplification. Diagnostic restriction enzyme assays revealed no evidence of double infections in 11 geographic strains of T. confusum, including the strain examined by Werren et al. (1995a). Further, sequence analysis of the Wolbachia ftsZ gene and an internal transcribed spacer (ITS) region in two of these strains displayed no nucleotide variation or evidence of polymorphisms. Results suggest that T. confusum is infected with B-group Wolbachia only. PMID:9263471

  10. Molecular characterization of Wolbachia infection in bed bugs (Cimex lectularius) collected from several localities in France

    PubMed Central

    Akhoundi, Mohammad; Cannet, Arnaud; Loubatier, Céline; Berenger, Jean-Michel; Izri, Arezki; Marty, Pierre; Delaunay, Pascal

    2016-01-01

    Wolbachia symbionts are maternally inherited intracellular bacteria that have been detected in numerous insects including bed bugs. The objective of this study, the first epidemiological study in Europe, was to screen Wolbachia infection among Cimex lectularius collected in the field, using PCR targeting the surface protein gene (wsp), and to compare obtained Wolbachia strains with those reported from laboratory colonies of C. lectularius as well as other Wolbachia groups. For this purpose, 284 bed bug specimens were caught and studied from eight different regions of France including the suburbs of Paris, Bouches-du-Rhône, Lot-et-Garonne, and five localities in Alpes-Maritimes. Among the samples, 166 were adults and the remaining 118 were considered nymphs. In all, 47 out of 118 nymphs (40%) and 61 out of 166 adults (37%) were found positive on wsp screening. Among the positive cases, 10 samples were selected randomly for sequencing. The sequences had 100% homology with wsp sequences belonging to the F-supergroup strains of Wolbachia. Therefore, we confirm the similarity of Wolbachia strains detected in this epidemiological study to Wolbachia spp. reported from laboratory colonies of C. lectularius. PMID:27492563

  11. Supergroup C Wolbachia, mutualist symbionts of filarial nematodes, have a distinct genome structure

    PubMed Central

    Comandatore, Francesco; Cordaux, Richard; Bandi, Claudio; Blaxter, Mark; Darby, Alistair; Makepeace, Benjamin L.; Montagna, Matteo; Sassera, Davide

    2015-01-01

    Wolbachia pipientis is possibly the most widespread endosymbiont of arthropods and nematodes. While all Wolbachia strains have historically been defined as a single species, 16 monophyletic clusters of diversity (called supergroups) have been described. Different supergroups have distinct host ranges and symbiotic relationships, ranging from mutualism to reproductive manipulation. In filarial nematodes, which include parasites responsible for major diseases of humans (such as Onchocerca volvulus, agent of river blindness) and companion animals (Dirofilaria immitis, the dog heartworm), Wolbachia has an obligate mutualist role and is the target of new treatment regimens. Here, we compare the genomes of eight Wolbachia strains, spanning the diversity of the major supergroups (A–F), analysing synteny, transposable element content, GC skew and gene loss or gain. We detected genomic features that differ between Wolbachia supergroups, most notably in the C and D clades from filarial nematodes. In particular, strains from supergroup C (symbionts of O. volvulus and D. immitis) present a pattern of GC skew, conserved synteny and lack of transposable elements, unique in the Wolbachia genus. These features could be the consequence of a distinct symbiotic relationship between C Wolbachia strains and their hosts, highlighting underappreciated differences between the mutualistic supergroups found within filarial nematodes. PMID:26631376

  12. Presence of extensive Wolbachia symbiont insertions discovered in the genome of its host Glossina morsitans morsitans.

    PubMed

    Brelsfoard, Corey; Tsiamis, George; Falchetto, Marco; Gomulski, Ludvik M; Telleria, Erich; Alam, Uzma; Doudoumis, Vangelis; Scolari, Francesca; Benoit, Joshua B; Swain, Martin; Takac, Peter; Malacrida, Anna R; Bourtzis, Kostas; Aksoy, Serap

    2014-04-01

    Tsetse flies (Glossina spp.) are the cyclical vectors of Trypanosoma spp., which are unicellular parasites responsible for multiple diseases, including nagana in livestock and sleeping sickness in humans in Africa. Glossina species, including Glossina morsitans morsitans (Gmm), for which the Whole Genome Sequence (WGS) is now available, have established symbiotic associations with three endosymbionts: Wigglesworthia glossinidia, Sodalis glossinidius and Wolbachia pipientis (Wolbachia). The presence of Wolbachia in both natural and laboratory populations of Glossina species, including the presence of horizontal gene transfer (HGT) events in a laboratory colony of Gmm, has already been shown. We herein report on the draft genome sequence of the cytoplasmic Wolbachia endosymbiont (cytWol) associated with Gmm. By in silico and molecular and cytogenetic analysis, we discovered and validated the presence of multiple insertions of Wolbachia (chrWol) in the host Gmm genome. We identified at least two large insertions of chrWol, 527,507 and 484,123 bp in size, from Gmm WGS data. Southern hybridizations confirmed the presence of Wolbachia insertions in Gmm genome, and FISH revealed multiple insertions located on the two sex chromosomes (X and Y), as well as on the supernumerary B-chromosomes. We compare the chrWol insertions to the cytWol draft genome in an attempt to clarify the evolutionary history of the HGT events. We discuss our findings in light of the evolution of Wolbachia infections in the tsetse fly and their potential impacts on the control of tsetse populations and trypanosomiasis.

  13. Wolbachia infection and mitochondrial DNA comparisons among Culex mosquitoes in South West Iran.

    PubMed

    Behbahani, A

    2012-01-01

    The control of mosquito borne diseases needs new methods given widespread insecticide resistance in many mosquito species. The inherited endosymbiont Wolbachia, found in many arthropods, provides a biological system to reduce the transmission of these diseases and replace the population of vectors with non-vectors using cytoplasmic incompatibility. The aim of this study was to understand the rate of Wolbachia infection among Culex species in the region and to see the effect of Wolbachia infection on mitochondrial genome. In this study three species of Culex mosquitoes were collected from Shoushtar in south west of Iran and examined for Wolbachia infection by Polymerase Chain Reaction (PCR). All of the C. quinquefasciatus specimens were infected with Wolbachia, while C. tritaeniorynchus and C. theileri showed no infection with Wolbachia. The 340 bp of AT rich of mtDNA was sequenced from 30 individuals, 10 individuals of each species. Three sequence haplotypes were found in C. tritaeniorynchus and C. theileri while there was only one haplotype in C. quinquefasciatus. The reduction of haplotypes diversity may be result of a sweep of Wolbachia in this species.

  14. Wolbachia infection and the expression of cytoplasmic incompatibility in sandflies (Diptera: Psychodidae) from Egypt.

    PubMed

    Kassem, H A; Hassan, A N; Abdel-Hamid, I; Osman, G; El Khalab, E M; Madkour, M A

    2003-09-01

    A PCR-based method was used to screen four laboratory colonies of sandflies for Wolbachia infection. The colonies - one of Phlebotomus langeroni, one of P. bergeroti and two of P. papatasi - were all derived from sandflies collected in Egypt. Only one of the colonies, derived from P. papatasi collected in Sinai, was found infected. The sequence of the PCR product for this colony was identical to that previously reported for the Wolbachia in P. papatasi from Israel. The induction with tetracycline of cytoplasmic incompatibility (CI) in flies from the P. papatasi (Sinai) colony was then investigated, through reciprocal crosses between treated and untreated P. papatasi siblings. Partial CI expression was attained in the crosses involving antibiotic-treated (i.e. uninfected) females, whether the males used were infected with Wolbachia or had also been cleared of Wolbachia by antibiotic treatment. Most (75%) of the eggs oviposited by uninfected females that had been crossed with infected males, and most (58%) of those laid by uninfected females that had been crossed with uninfected males, failed to hatch. These results provide the first published evidence showing that Wolbachia infection in sandflies is advantageous to the insects. The failure to detect Wolbachia in one of the colonies derived from Egyptian P. papatasi or in the colonies derived from Egyptian P. bergeroti and P. langeroni may indicate that the inter- and intra-specific spread of Wolbachia is discontinuous, even within one country.

  15. Wolbachia Influences the Production of Octopamine and Affects Drosophila Male Aggression

    PubMed Central

    Rohrscheib, Chelsie E.; Bondy, Elizabeth; Josh, Peter; Riegler, Markus; Eyles, Darryl; van Swinderen, Bruno; Weible, Michael W.

    2015-01-01

    Wolbachia bacteria are endosymbionts that infect approximately 40% of all insect species and are best known for their ability to manipulate host reproductive systems. Though the effect Wolbachia infection has on somatic tissues is less well understood, when present in cells of the adult Drosophila melanogaster brain, Wolbachia exerts an influence over behaviors related to olfaction. Here, we show that a strain of Wolbachia influences male aggression in flies, which is critically important in mate competition. A specific strain of Wolbachia was observed to reduce the initiation of aggressive encounters in Drosophila males compared to the behavior of their uninfected controls. To determine how Wolbachia was able to alter aggressive behavior, we investigated the role of octopamine, a neurotransmitter known to influence male aggressive behavior in many insect species. Transcriptional analysis of the octopamine biosynthesis pathway revealed that two essential genes, the tyrosine decarboxylase and tyramine β-hydroxylase genes, were significantly downregulated in Wolbachia-infected flies. Quantitative chemical analysis also showed that total octopamine levels were significantly reduced in the adult heads. PMID:25934616

  16. Wolbachia Influences the Maternal Transmission of the gypsy Endogenous Retrovirus in Drosophila melanogaster

    PubMed Central

    Touret, Franck; Guiguen, François

    2014-01-01

    ABSTRACT The endosymbiotic bacteria of the genus Wolbachia are present in most insects and are maternally transmitted through the germline. Moreover, these intracellular bacteria exert antiviral activity against insect RNA viruses, as in Drosophila melanogaster, which could explain the prevalence of Wolbachia bacteria in natural populations. Wolbachia is maternally transmitted in D. melanogaster through a mechanism that involves distribution at the posterior pole of mature oocytes and then incorporation into the pole cells of the embryos. In parallel, maternal transmission of several endogenous retroviruses is well documented in D. melanogaster. Notably, gypsy retrovirus is expressed in permissive follicle cells and transferred to the oocyte and then to the offspring by integrating into their genomes. Here, we show that the presence of Wolbachia wMel reduces the rate of gypsy insertion into the ovo gene. However, the presence of Wolbachia does not modify the expression levels of gypsy RNA and envelope glycoprotein from either permissive or restrictive ovaries. Moreover, Wolbachia affects the pattern of distribution of the retroviral particles and the gypsy envelope protein in permissive follicle cells. Altogether, our results enlarge the knowledge of the antiviral activity of Wolbachia to include reducing the maternal transmission of endogenous retroviruses in D. melanogaster. PMID:25182324

  17. Unravelling the Wolbachia evolutionary role: the reprogramming of the host genomic imprinting.

    PubMed

    Negri, Ilaria; Franchini, Antonella; Gonella, Elena; Daffonchio, Daniele; Mazzoglio, Peter John; Mandrioli, Mauro; Alma, Alberto

    2009-07-07

    Environmental factors can induce significant epigenetic changes that may also be inherited by future generations. The maternally inherited symbiont of arthropods Wolbachia pipientis is an excellent candidate as an 'environmental' factor promoting trans-generational epigenetic changes: by establishing intimate relationships with germ-line cells, epigenetic effects of Wolbachia symbiosis would be manifested as a 'maternal effect', in which infection of the mother modulates the offspring phenotype. In the leafhopper Zyginidia pullula, Wolbachia feminizes genetic males, leaving them as intersexes. With the exception of male chitinous structures that are present in the last abdominal segment, feminized males display phenotypic features that are typical of females. These include ovaries that range from a typical histological architecture to an altered structure. Methylation-sensitive random amplification of polymorphic DNA profiles show that they possess a female genomic imprint. On the other hand, some rare feminized males bear testes instead of ovaries. These specimens possess a Wolbachia density approximately four orders of magnitude lower than feminized males with ovaries and maintain a male genome-methylation pattern. Our results indicate that Wolbachia infection disrupts male imprinting, which dramatically influences the expression of genes involved in sex differentiation and development, and the alteration occurs only if Wolbachia exceeds a density threshold. Thus, a new Wolbachia's role as an environmental evolutionary force, inducing epigenetic trans-generational changes, should now be considered.

  18. Molecular evidence for single Wolbachia infections among geographic strains of the flour beetle Tribolium confusum.

    PubMed

    Fialho, R F; Stevens, L

    1997-07-22

    Infections with the rickettsial microorganism Wolbachia are cytoplasmically inherited and occur in a wide range of insect species and several other arthropods. Wolbachia infection often results in unidirectional cytoplasmic incompatibility (CI): crosses between infected males and uninfected females are incompatible and show a reduction of progeny or complete inviability. Unidirectional CI can also occur when males harbouring two incompatible Wolbachia strains are crossed with females infected with only one of the two strains. In the flour beetle Tribolium confusum, Wolbachia infections are of particular interest because of the severity of incompatibility. Typically, no progeny results from the incompatible cross, whereas only partial incompatibility is observed in most other hosts. Werren et al. (1995a) reported that Wolbachia infections in T. confusum consist of two bacterial strains belonging to distinct phylogenic groups, based on PCR amplification and sequence analysis of the bacterial cell division gene ftsZ. However, Fialho & Stevens (1996) showed that eight strains of T. confusum were infected with a single and common incompatibility type. Here we report analysis of the ftsZ gene by specific PCR amplification. Diagnostic restriction enzyme assays revealed no evidence of double infections in 11 geographic strains of T. confusum, including the strain examined by Werren et al. (1995a). Further, sequence analysis of the Wolbachia ftsZ gene and an internal transcribed spacer (ITS) region in two of these strains displayed no nucleotide variation or evidence of polymorphisms. Results suggest that T. confusum is infected with B-group Wolbachia only.

  19. Longicorn beetle that vectors pinewood nematode carries many Wolbachia genes on an autosome.

    PubMed

    Aikawa, Takuya; Anbutsu, Hisashi; Nikoh, Naruo; Kikuchi, Taisei; Shibata, Fukashi; Fukatsu, Takema

    2009-11-07

    Monochamus alternatus is the longicorn beetle notorious as a vector of the pinewood nematode that causes the pine wilt disease. When two populations of M. alternatus were subjected to diagnostic polymerase chain reaction (PCR) detection of four Wolbachia genes, only the ftsZ gene was detected from one of the populations. The Wolbachia ftsZ gene persisted even after larvae were fed with a tetracycline-containing diet for six weeks. The inheritance of the ftsZ gene was not maternal but biparental, exhibiting a typical Mendelian pattern. The ftsZ gene titres in homozygotic ftsZ(+) insects were nearly twice as high as those in heterozygotic ftsZ(+) insects. Exhaustive PCR surveys revealed that 31 and 30 of 214 Wolbachia genes examined were detected from the two insect populations, respectively. Many of these Wolbachia genes contained stop codon(s) and/or frame shift(s). Fluorescent in situ hybridization confirmed the location of the Wolbachia genes on an autosome. On the basis of these results, we conclude that a large Wolbachia genomic region has been transferred to and located on an autosome of M. alternatus. The discovery of massive gene transfer from Wolbachia to M. alternatus would provide further insights into the evolution and fate of laterally transferred endosymbiont genes in multicellular host organisms.

  20. Longicorn beetle that vectors pinewood nematode carries many Wolbachia genes on an autosome

    PubMed Central

    Aikawa, Takuya; Anbutsu, Hisashi; Nikoh, Naruo; Kikuchi, Taisei; Shibata, Fukashi; Fukatsu, Takema

    2009-01-01

    Monochamus alternatus is the longicorn beetle notorious as a vector of the pinewood nematode that causes the pine wilt disease. When two populations of M. alternatus were subjected to diagnostic polymerase chain reaction (PCR) detection of four Wolbachia genes, only the ftsZ gene was detected from one of the populations. The Wolbachia ftsZ gene persisted even after larvae were fed with a tetracycline-containing diet for six weeks. The inheritance of the ftsZ gene was not maternal but biparental, exhibiting a typical Mendelian pattern. The ftsZ gene titres in homozygotic ftsZ+ insects were nearly twice as high as those in heterozygotic ftsZ+ insects. Exhaustive PCR surveys revealed that 31 and 30 of 214 Wolbachia genes examined were detected from the two insect populations, respectively. Many of these Wolbachia genes contained stop codon(s) and/or frame shift(s). Fluorescent in situ hybridization confirmed the location of the Wolbachia genes on an autosome. On the basis of these results, we conclude that a large Wolbachia genomic region has been transferred to and located on an autosome of M. alternatus. The discovery of massive gene transfer from Wolbachia to M. alternatus would provide further insights into the evolution and fate of laterally transferred endosymbiont genes in multicellular host organisms. PMID:19692404

  1. Presence of Extensive Wolbachia Symbiont Insertions Discovered in the Genome of Its Host Glossina morsitans morsitans

    PubMed Central

    Falchetto, Marco; Gomulski, Ludvik M.; Telleria, Erich; Alam, Uzma; Doudoumis, Vangelis; Scolari, Francesca; Benoit, Joshua B.; Swain, Martin; Takac, Peter; Malacrida, Anna R.; Bourtzis, Kostas; Aksoy, Serap

    2014-01-01

    Tsetse flies (Glossina spp.) are the cyclical vectors of Trypanosoma spp., which are unicellular parasites responsible for multiple diseases, including nagana in livestock and sleeping sickness in humans in Africa. Glossina species, including Glossina morsitans morsitans (Gmm), for which the Whole Genome Sequence (WGS) is now available, have established symbiotic associations with three endosymbionts: Wigglesworthia glossinidia, Sodalis glossinidius and Wolbachia pipientis (Wolbachia). The presence of Wolbachia in both natural and laboratory populations of Glossina species, including the presence of horizontal gene transfer (HGT) events in a laboratory colony of Gmm, has already been shown. We herein report on the draft genome sequence of the cytoplasmic Wolbachia endosymbiont (cytWol) associated with Gmm. By in silico and molecular and cytogenetic analysis, we discovered and validated the presence of multiple insertions of Wolbachia (chrWol) in the host Gmm genome. We identified at least two large insertions of chrWol, 527,507 and 484,123 bp in size, from Gmm WGS data. Southern hybridizations confirmed the presence of Wolbachia insertions in Gmm genome, and FISH revealed multiple insertions located on the two sex chromosomes (X and Y), as well as on the supernumerary B-chromosomes. We compare the chrWol insertions to the cytWol draft genome in an attempt to clarify the evolutionary history of the HGT events. We discuss our findings in light of the evolution of Wolbachia infections in the tsetse fly and their potential impacts on the control of tsetse populations and trypanosomiasis. PMID:24763283

  2. Wolbachia infections in world populations of bean beetles (Coleoptera: Chrysomelidae: Bruchinae) infesting cultivated and wild legumes.

    PubMed

    Kondo, Natsuko I; Tuda, Midori; Toquenaga, Yukihiko; Lan, Yen-Chiu; Buranapanichpan, Sawai; Horng, Shwu-Bin; Shimada, Masakazu; Fukatsu, Takema

    2011-07-01

    Wolbachia endosymbionts are widespread among insects and other arthropods, often causing cytoplasmic incompatibility and other reproductive phenotypes in their hosts. Recently, possibilities of Wolbachia-mediated pest control and management have been proposed, and the bean beetles of the subfamily Bruchinae are known as serious pests of harvested and stored beans worldwide. Here we investigated Wolbachia infections in bean beetles from the world, representing seven genera, 20 species and 87 populations. Of 20 species examined, Wolbachia infections were detected in four species, Megabruchidius sophorae, Callosobruchus analis, C. latealbus and C. chinensis. Infection frequencies were partial in M. sophorae but perfect in the other species. In addition to C. chinensis described in the previous studies, C. latealbus was infected with two distinct Wolbachia strains. These Wolbachia strains from the bean beetles were phylogenetically not closely related to each other. Among world populations of C. chinensis, some Taiwanese populations on a wild leguminous plant, Rhynchosia minima, exhibited a peculiar Wolbachia infection pattern, suggesting the possibility that these populations comprise a distinct host race or a cryptic species.

  3. Onchocerciasis: the Role of Wolbachia Bacterial Endosymbionts in Parasite Biology, Disease Pathogenesis, and Treatment

    PubMed Central

    Tamarozzi, Francesca; Halliday, Alice; Gentil, Katrin; Hoerauf, Achim; Pearlman, Eric; Taylor, Mark J.

    2011-01-01

    Summary: The discovery of Wolbachia intracellular bacteria within filarial nematodes, including Onchocerca volvulus, the causative agent of onchocerciasis or “river blindness,” has delivered a paradigm shift in our understanding of the parasite's biology, to where we now know that the bacterial endosymbionts are essential for normal development of larvae and embryos and may support the long-term survival of adult worms. The apparent mutualistic dependency has also offered a novel approach to the treatment of onchocerciasis through the use of antibiotics to eliminate Wolbachia, delivering for the first time a treatment which has significant macrofilaricidal efficacy. Studies with other filarial nematode species have also highlighted a role for Wolbachia in transmission and infection of the mammalian host through a fascinating manipulation of mast cell-mediated vasodilation to enhance infectivity of vector-borne larvae. Wolbachia has also been identified as the principal driver of innate and adaptive Th1 inflammatory immunity, which can either contribute to disease pathogenesis or, with the Wolbachia-mediated recruitment of mast cells, enhance infectivity. The Wolbachia activation of innate inflammation also drives inflammatory adverse events in response to chemotherapy with either diethylcarbamazine (DEC) or ivermectin. In this review we summarize the experimental and field trial data which have uncovered the importance of Wolbachia symbiosis in onchocerciasis. PMID:21734243

  4. Fitness advantage and cytoplasmic incompatibility in Wolbachia single- and superinfected Aedes albopictus.

    PubMed

    Dobson, S L; Rattanadechakul, W; Marsland, E J

    2004-08-01

    Wolbachia are obligate, maternally inherited, intracellular bacteria that infect numerous insects and other invertebrates. Wolbachia infections have evolved multiple mechanisms to manipulate host reproduction and facilitate invasion of naive host populations. One such mechanism is cytoplasmic incompatibility (CI) that occurs in many insect species, including Aedes albopictus (Asian tiger mosquito). The multiple Wolbachia infections that occur naturally in A. albopictus make this mosquito a useful system in which to study CI. Here, experiments employ mosquito strains that have been introgressed to provide genetically similar strains that harbor differing Wolbachia infection types. Cytoplasmic incompatibility levels, host longevity, egg hatch rates, and fecundity are examined. Crossing results demonstrate a pattern of additive unidirectional cytoplasmic incompatibility. Furthermore, relative to uninfected females, infected females are at a reproductive advantage due to both cytoplasmic incompatibility and a fitness increase associated with Wolbachia infection. In contrast, no fitness difference was observed in comparisons of single- and superinfected females. We discuss the observed results in regard to the evolution of the Wolbachia/A. albopictus symbiosis and the observed pattern of Wolbachia infection in natural populations.

  5. Detection of Wolbachia in Aedes albopictus and Their Effects on Chikungunya Virus.

    PubMed

    Ahmad, Noor Afizah; Vythilingam, Indra; Lim, Yvonne A L; Zabari, Nur Zatil Aqmar M; Lee, Han Lim

    2017-01-11

    Wolbachia-based vector control strategies have been proposed as a means to augment the currently existing measures for controlling dengue and chikungunya vectors. Prior to utilizing Wolbachia as a novel vector control strategy, it is crucial to understand the Wolbachia-mosquito interactions. In this study, field surveys were conducted to screen for the infection status of Wolbachia in field-collected Aedes albopictus The effects of Wolbachia in its native host toward the replication and dissemination of chikungunya virus (CHIKV) was also studied. The prevalence of Wolbachia-infected field-collected Ae. albopictus was estimated to be 98.6% (N = 142) for females and 95.1% (N = 102) for males in the population studied. The Ae. albopictus were naturally infected with both wAlbA and wAlbB strains. We also found that the native Wolbachia has no impact on CHIKV infection and minimal effect on CHIKV dissemination to secondary organs. © The American Society of Tropical Medicine and Hygiene.

  6. Heat Sensitivity of wMel Wolbachia during Aedes aegypti Development.

    PubMed

    Ulrich, Jill N; Beier, John C; Devine, Gregor J; Hugo, Leon E

    2016-07-01

    The wMel strain of Wolbachia bacteria is known to prevent dengue and Zika virus transmission in the mosquito vector Aedes aegypti. Accordingly, the release of wMel-infected A. aegypti in endemic regions has been recommended by the World Health Organization as a potential strategy for controlling dengue and Zika outbreaks. However, the utility of this approach could be limited if high temperatures in the aquatic habitats where A. aegypti develop are detrimental to Wolbachia. We exposed wMel-infected A. aegypti eggs and larvae to fluctuating daily temperatures of 30-40°C for three, five, or seven days during their development. We found that Wolbachia levels in females emerging from heat treatments were significantly lower than in the controls that had developed at 20-30°C. Notably, seven days of high temperatures starting at the egg stage reduced Wolbachia levels in emerging females to less than 0.1% of the wMel control levels. However, after adult females returned to 20-30°C for 4-7 days, they experienced differing degrees of Wolbachia recovery. Our findings suggest that the spread of Wolbachia in wild A. aegypti populations and any consequent protection from dengue and Zika viruses might be limited in ecosystems that experience periods of extreme heat, but Wolbachia levels recover partially after temperatures return to normal.

  7. Wolbachia Influences the Production of Octopamine and Affects Drosophila Male Aggression.

    PubMed

    Rohrscheib, Chelsie E; Bondy, Elizabeth; Josh, Peter; Riegler, Markus; Eyles, Darryl; van Swinderen, Bruno; Weible, Michael W; Brownlie, Jeremy C

    2015-07-01

    Wolbachia bacteria are endosymbionts that infect approximately 40% of all insect species and are best known for their ability to manipulate host reproductive systems. Though the effect Wolbachia infection has on somatic tissues is less well understood, when present in cells of the adult Drosophila melanogaster brain, Wolbachia exerts an influence over behaviors related to olfaction. Here, we show that a strain of Wolbachia influences male aggression in flies, which is critically important in mate competition. A specific strain of Wolbachia was observed to reduce the initiation of aggressive encounters in Drosophila males compared to the behavior of their uninfected controls. To determine how Wolbachia was able to alter aggressive behavior, we investigated the role of octopamine, a neurotransmitter known to influence male aggressive behavior in many insect species. Transcriptional analysis of the octopamine biosynthesis pathway revealed that two essential genes, the tyrosine decarboxylase and tyramine β-hydroxylase genes, were significantly downregulated in Wolbachia-infected flies. Quantitative chemical analysis also showed that total octopamine levels were significantly reduced in the adult heads. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. Comparative Analysis of Wolbachia Genomes Reveals Streamlining and Divergence of Minimalist Two-Component Systems

    PubMed Central

    Christensen, Steen; Serbus, Laura Renee

    2015-01-01

    Two-component regulatory systems are commonly used by bacteria to coordinate intracellular responses with environmental cues. These systems are composed of functional protein pairs consisting of a sensor histidine kinase and cognate response regulator. In contrast to the well-studied Caulobacter crescentus system, which carries dozens of these pairs, the streamlined bacterial endosymbiont Wolbachia pipientis encodes only two pairs: CckA/CtrA and PleC/PleD. Here, we used bioinformatic tools to compare characterized two-component system relays from C. crescentus, the related Anaplasmataceae species Anaplasma phagocytophilum and Ehrlichia chaffeensis, and 12 sequenced Wolbachia strains. We found the core protein pairs and a subset of interacting partners to be highly conserved within Wolbachia and these other Anaplasmataceae. Genes involved in two-component signaling were positioned differently within the various Wolbachia genomes, whereas the local context of each gene was conserved. Unlike Anaplasma and Ehrlichia, Wolbachia two-component genes were more consistently found clustered with metabolic genes. The domain architecture and key functional residues standard for two-component system proteins were well-conserved in Wolbachia, although residues that specify cognate pairing diverged substantially from other Anaplasmataceae. These findings indicate that Wolbachia two-component signaling pairs share considerable functional overlap with other α-proteobacterial systems, whereas their divergence suggests the potential for regulatory differences and cross-talk. PMID:25809075

  9. Comparative analysis of wolbachia genomes reveals streamlining and divergence of minimalist two-component systems.

    PubMed

    Christensen, Steen; Serbus, Laura Renee

    2015-03-24

    Two-component regulatory systems are commonly used by bacteria to coordinate intracellular responses with environmental cues. These systems are composed of functional protein pairs consisting of a sensor histidine kinase and cognate response regulator. In contrast to the well-studied Caulobacter crescentus system, which carries dozens of these pairs, the streamlined bacterial endosymbiont Wolbachia pipientis encodes only two pairs: CckA/CtrA and PleC/PleD. Here, we used bioinformatic tools to compare characterized two-component system relays from C. crescentus, the related Anaplasmataceae species Anaplasma phagocytophilum and Ehrlichia chaffeensis, and 12 sequenced Wolbachia strains. We found the core protein pairs and a subset of interacting partners to be highly conserved within Wolbachia and these other Anaplasmataceae. Genes involved in two-component signaling were positioned differently within the various Wolbachia genomes, whereas the local context of each gene was conserved. Unlike Anaplasma and Ehrlichia, Wolbachia two-component genes were more consistently found clustered with metabolic genes. The domain architecture and key functional residues standard for two-component system proteins were well-conserved in Wolbachia, although residues that specify cognate pairing diverged substantially from other Anaplasmataceae. These findings indicate that Wolbachia two-component signaling pairs share considerable functional overlap with other α-proteobacterial systems, whereas their divergence suggests the potential for regulatory differences and cross-talk. Copyright © 2015 Christensen and Serbus.

  10. Discovery of putative small non-coding RNAs from the obligate intracellular bacterium Wolbachia pipientis.

    PubMed

    Woolfit, Megan; Algama, Manjula; Keith, Jonathan M; McGraw, Elizabeth A; Popovici, Jean

    2015-01-01

    Wolbachia pipientis is an endosymbiotic bacterium that induces a wide range of effects in its insect hosts, including manipulation of reproduction and protection against pathogens. Little is known of the molecular mechanisms underlying the insect-Wolbachia interaction, though it is likely to be mediated via the secretion of proteins or other factors. There is an increasing amount of evidence that bacteria regulate many cellular processes, including secretion of virulence factors, using small non-coding RNAs (sRNAs), but sRNAs have not previously been described from Wolbachia. We have used two independent approaches, one based on comparative genomics and the other using RNA-Seq data generated for gene expression studies, to identify candidate sRNAs in Wolbachia. We experimentally characterized the expression of one of these candidates in four Wolbachia strains, and showed that it is differentially regulated in different host tissues and sexes. Given the roles played by sRNAs in other host-associated bacteria, the conservation of the candidate sRNAs between different Wolbachia strains, and the sex- and tissue-specific differential regulation we have identified, we hypothesise that sRNAs may play a significant role in the biology of Wolbachia, and in particular in its interactions with its host.

  11. Diet-Induced Nutritional Stress and Pathogen Interference in Wolbachia-Infected Aedes aegypti.

    PubMed

    Caragata, Eric Pearce; Rezende, Fernanda Oliveira; Simões, Taynãna César; Moreira, Luciano Andrade

    2016-11-01

    The pathogen interference phenotype greatly restricts infection with dengue virus (DENV) and other pathogens in Wolbachia-infected Aedes aegypti, and is a vital component of Wolbachia-based mosquito control. Critically, the phenotype's causal mechanism is complex and poorly understood, with recent evidence suggesting that the cause may be species specific. To better understand this important phenotype, we investigated the role of diet-induced nutritional stress on interference against DENV and the avian malarial parasite Plasmodium gallinaceum in Wolbachia-infected Ae. aegypti, and on physiological processes linked to the phenotype. Wolbachia-infected mosquitoes were fed one of four different concentrations of sucrose, and then challenged with either P. gallinaceum or DENV. Interference against P. gallinaceum was significantly weakened by the change in diet however there was no effect on DENV interference. Immune gene expression and H2O2 levels have previously been linked to pathogen interference. These traits were assayed for mosquitoes on each diet using RT-qPCR and the Amplex Red Hydrogen Peroxide/Peroxidase Assay Kit, and it was observed that the change in diet did not significantly affect immune expression, but low carbohydrate levels led to a loss of ROS induction in Wolbachia-infected mosquitoes. Our data suggest that host nutrition may not influence DENV interference for Wolbachia-infected mosquitoes, but Plasmodium interference may be linked to both nutrition and oxidative stress. This pathogen-specific response to nutritional change highlights the complex nature of interactions between Wolbachia and pathogens in mosquitoes.

  12. Supergroup C Wolbachia, mutualist symbionts of filarial nematodes, have a distinct genome structure.

    PubMed

    Comandatore, Francesco; Cordaux, Richard; Bandi, Claudio; Blaxter, Mark; Darby, Alistair; Makepeace, Benjamin L; Montagna, Matteo; Sassera, Davide

    2015-12-01

    Wolbachia pipientis is possibly the most widespread endosymbiont of arthropods and nematodes. While all Wolbachia strains have historically been defined as a single species, 16 monophyletic clusters of diversity (called supergroups) have been described. Different supergroups have distinct host ranges and symbiotic relationships, ranging from mutualism to reproductive manipulation. In filarial nematodes, which include parasites responsible for major diseases of humans (such as Onchocerca volvulus, agent of river blindness) and companion animals (Dirofilaria immitis, the dog heartworm), Wolbachia has an obligate mutualist role and is the target of new treatment regimens. Here, we compare the genomes of eight Wolbachia strains, spanning the diversity of the major supergroups (A-F), analysing synteny, transposable element content, GC skew and gene loss or gain. We detected genomic features that differ between Wolbachia supergroups, most notably in the C and D clades from filarial nematodes. In particular, strains from supergroup C (symbionts of O. volvulus and D. immitis) present a pattern of GC skew, conserved synteny and lack of transposable elements, unique in the Wolbachia genus. These features could be the consequence of a distinct symbiotic relationship between C Wolbachia strains and their hosts, highlighting underappreciated differences between the mutualistic supergroups found within filarial nematodes. © 2015 The Authors.

  13. Localization of a filarial phosphate permease that is up-regulated in response to depletion of essential Wolbachia endobacteria.

    PubMed

    Arumugam, Sridhar; Hoerauf, Achim; Pfarr, Kenneth M

    2014-03-01

    Wolbachia of filarial nematodes are essential, obligate endobacteria. When depleted by doxycycline worm embryogenesis, larval development and worm survival are inhibited. The molecular basis governing the endosymbiosis between Wolbachia and their filarial host is still being deciphered. In rodent filarial nematode Litomosoides sigmodontis, a nematode encoded phosphate permease gene (Ls-ppe-1) was up-regulated at the mRNA level in response to Wolbachia depletion and this gene promises to have an important role in Wolbachia-nematode endosymbiosis. To further characterize this gene, the regulation of phosphate permease during Wolbachia depletion was studied at the protein level in L. sigmodontis and in the human filaria Onchocerca volvulus. And the localization of phosphate permease (PPE) and Wolbachia in L. sigmodontis and O. volvulus was investigated in untreated and antibiotic treated worms. Depletion of Wolbachia by tetracycline (Tet) resulted in up-regulation of Ls-ppe-1 in L. sigmodontis. On day 36 of Tet treatment, compared to controls (Con), >98% of Wolbachia were depleted with a 3-fold increase in mRNA levels of Ls-ppe-1. Anti-Ls-PPE serum used in Western blots showed up-regulation of Ls-PPE at the protein level in Tet worms on day 15 and 36 of treatment. Immunohistology revealed the localization of Wolbachia and Ls-PPE in the embryos, microfilariae and hypodermis of L. sigmodontis female worms and up-regulation of Ls-PPE in response to Wolbachia depletion. Expression of O. volvulus phosphate permease (Ov-PPE) studied using anti-Ov-PPE serum, showed up-regulation of Ov-PPE at the protein level in doxycycline treated Wolbachia depleted O. volvulus worms and immunohistology revealed localization of Ov-PPE and Wolbachia and up-regulation of Ov-PPE in the hypodermis and embryos of doxycycline treated worms. Ls-PPE and Ov-PPE are upregulated upon Wolbachia depletion in same tissues and regions where Wolbachia are located in untreated worms, reinforcing a link

  14. Wolbachia association with the tsetse fly, Glossina fuscipes fuscipes, reveals high levels of genetic diversity and complex evolutionary dynamics

    PubMed Central

    2013-01-01

    Background Wolbachia pipientis, a diverse group of α-proteobacteria, can alter arthropod host reproduction and confer a reproductive advantage to Wolbachia-infected females (cytoplasmic incompatibility (CI)). This advantage can alter host population genetics because Wolbachia-infected females produce more offspring with their own mitochondrial DNA (mtDNA) haplotypes than uninfected females. Thus, these host haplotypes become common or fixed (selective sweep). Although simulations suggest that for a CI-mediated sweep to occur, there must be a transient phase with repeated initial infections of multiple individual hosts by different Wolbachia strains, this has not been observed empirically. Wolbachia has been found in the tsetse fly, Glossina fuscipes fuscipes, but it is not limited to a single host haplotype, suggesting that CI did not impact its population structure. However, host population genetic differentiation could have been generated if multiple Wolbachia strains interacted in some populations. Here, we investigated Wolbachia genetic variation in G. f. fuscipes populations of known host genetic composition in Uganda. We tested for the presence of multiple Wolbachia strains using Multi-Locus Sequence Typing (MLST) and for an association between geographic region and host mtDNA haplotype using Wolbachia DNA sequence from a variable locus, groEL (heat shock protein 60). Results MLST demonstrated that some G. f. fuscipes carry Wolbachia strains from two lineages. GroEL revealed high levels of sequence diversity within and between individuals (Haplotype diversity = 0.945). We found Wolbachia associated with 26 host mtDNA haplotypes, an unprecedented result. We observed a geographical association of one Wolbachia lineage with southern host mtDNA haplotypes, but it was non-significant (p = 0.16). Though most Wolbachia-infected host haplotypes were those found in the contact region between host mtDNA groups, this association was non-significant (p = 0

  15. Airline passenger misconduct: management implications for physicians.

    PubMed

    Pierson, Kathleen; Power, Yuri; Marcus, Adeyinka; Dahlberg, Angela

    2007-04-01

    The history and etiology of airline passenger misconduct are discussed and relevant medico-legal and management implications reviewed. The medical literature was reviewed and supplemented with internet searches for relevant information. Organizations including the Federal Aviation Administration, International Air Transport Association, Transportation Safety Board of Canada, and the Canadian Transportation Agency were contacted for unpublished information. Three cases of in-flight psychiatric emergencies in which two of the authors were involved are presented along with a review of relevant literature pertaining to the etiology and medical management of passenger misconduct. Recommendations for the in-flight management of disruptive passengers are discussed. Incidents of in-flight passenger misconduct represent a serious threat to passenger safety. The three cases presented highlight the difficulties involved in managing incidents of passenger misconduct in the context of limited resources and treatment options aboard aircraft. Ambiguity remains in regard to the responding physician's medico-legal obligations (and liabilities) during the management of an unruly passenger. However, liability risks appear minimal at this time. Awareness of the causes of passenger misconduct is required to adequately prevent, identify, and treat in-flight cases of passenger misconduct. Although most physicians will not be obligated to respond, liability issues do not appear to be a major factor preventing the offer of medical assistance.

  16. US Advanced Freight and Passenger MAGLEV System

    NASA Technical Reports Server (NTRS)

    Morena, John J.; Danby, Gordon; Powell, James

    1996-01-01

    Japan and Germany will operate first generation Maglev passenger systems commercially shortly after 2000 A.D. The United States Maglev systems will require sophisticated freight and passenger carrying capability. The U.S. freight market is larger than passenger transport. A proposed advanced freight and passenger Maglev Project in Brevard County Florida is described. Present Maglev systems cost 30 million dollars or more per mile. Described is an advanced third generation Maglev system with technology improvements that will result in a cost of 10 million dollars per mile.

  17. Extreme divergence of Wolbachia tropism for the stem-cell-niche in the Drosophila testis.

    PubMed

    Toomey, Michelle E; Frydman, Horacio M

    2014-12-01

    Microbial tropism, the infection of specific cells and tissues by a microorganism, is a fundamental aspect of host-microbe interactions. The intracellular bacteria Wolbachia have a peculiar tropism for the stem cell niches in the Drosophila ovary, the microenvironments that support the cells producing the eggs. The molecular underpinnings of Wolbachia stem cell niche tropism are unknown. We have previously shown that the patterns of tropism in the ovary show a high degree of conservation across the Wolbachia lineage, with closely related Wolbachia strains usually displaying the same pattern of stem cell niche tropism. It has also been shown that tropism to these structures in the ovary facilitates both vertical and horizontal transmission, providing a strong selective pressure towards evolutionary conservation of tropism. Here we show great disparity in the evolutionary conservation and underlying mechanisms of stem cell niche tropism between male and female gonads. In contrast to females, niche tropism in the male testis is not pervasive, present in only 45% of niches analyzed. The patterns of niche tropism in the testis are not evolutionarily maintained across the Wolbachia lineage, unlike what was shown in the females. Furthermore, hub tropism does not correlate with cytoplasmic incompatibility, a Wolbachia-driven phenotype imprinted during spermatogenesis. Towards identifying the molecular mechanism of hub tropism, we performed hybrid analyses of Wolbachia strains in non-native hosts. These results indicate that both Wolbachia and host derived factors play a role in the targeting of the stem cell niche in the testis. Surprisingly, even closely related Wolbachia strains in Drosophila melanogaster, derived from a single ancestor only 8,000 years ago, have significantly different tropisms to the hub, highlighting that stem cell niche tropism is rapidly diverging in males. These findings provide a powerful system to investigate the mechanisms and evolution of

  18. Costs of Three Wolbachia Infections on the Survival of Aedes aegypti Larvae under Starvation Conditions

    PubMed Central

    Ross, Perran A.; Endersby, Nancy M.; Hoffmann, Ary A.

    2016-01-01

    The mosquito Aedes aegypti, the principal vector of dengue virus, has recently been infected experimentally with Wolbachia: intracellular bacteria that possess potential as dengue biological control agents. Wolbachia depend on their hosts for nutrients they are unable to synthesize themselves. Consequently, competition between Wolbachia and their host for resources could reduce host fitness under the competitive conditions commonly experienced by larvae of Ae. aegypti in the field, hampering the invasion of Wolbachia into natural mosquito populations. We assess the survival and development of Ae. aegypti larvae under starvation conditions when infected with each of three experimentally-generated Wolbachia strains: wMel, wMelPop and wAlbB, and compare their fitness to wild-type uninfected larvae. We find that all three Wolbachia infections reduce the survival of larvae relative to those that are uninfected, and the severity of the effect is concordant with previously characterized fitness costs to other life stages. We also investigate the ability of larvae to recover from extended food deprivation and find no effect of Wolbachia on this trait. Aedes aegypti larvae of all infection types were able to resume their development after one month of no food, pupate rapidly, emerge at a large size, and exhibit complete cytoplasmic incompatibility and maternal transmission. A lowered ability of Wolbachia-infected larvae to survive under starvation conditions will increase the threshold infection frequency required for Wolbachia to establish in highly competitive natural Ae. aegypti populations and will also reduce the speed of invasion. This study also provides insights into survival strategies of larvae when developing in stressful environments. PMID:26745630

  19. Wolbachia infections that reduce immature insect survival: Predicted impacts on population replacement

    PubMed Central

    2011-01-01

    Background The evolutionary success of Wolbachia bacteria, infections of which are widespread in invertebrates, is largely attributed to an ability to manipulate host reproduction without imposing substantial fitness costs. Here, we describe a stage-structured model with deterministic immature lifestages and a stochastic adult female lifestage. Simulations were conducted to better understand Wolbachia invasions into uninfected host populations. The model includes conventional Wolbachia parameters (the level of cytoplasmic incompatibility, maternal inheritance, the relative fecundity of infected females, and the initial Wolbachia infection frequency) and a new parameter termed relative larval viability (RLV), which is the survival of infected larvae relative to uninfected larvae. Results The results predict the RLV parameter to be the most important determinant for Wolbachia invasion and establishment. Specifically, the fitness of infected immature hosts must be close to equal to that of uninfected hosts before population replacement can occur. Furthermore, minute decreases in RLV inhibit the invasion of Wolbachia despite high levels of cytoplasmic incompatibility, maternal inheritance, and low adult fitness costs. Conclusions The model described here takes a novel approach to understanding the spread of Wolbachia through a population with explicit dynamics. By combining a stochastic female adult lifestage and deterministic immature/adult male lifestages, the model predicts that even those Wolbachia infections that cause minor decreases in immature survival are unlikely to invade and spread within the host population. The results are discussed in relation to recent theoretical and empirical studies of natural population replacement events and proposed applied research, which would use Wolbachia as a tool to manipulate insect populations. PMID:21975225

  20. Variations in the sensitivity of different primers for detecting Wolbachia in Anastrepha (diptera: tephritidae)

    PubMed Central

    Marcon, Helena Sanches; Coscrato, Virgínia Elias; Selivon, Denise; Perondini, André Luiz Paranhos; Marino, Celso Luis

    2011-01-01

    Wolbachia are endosymbiont bacteria of the family Rickettsiacea that are widespread in invertebrates and occur between 20% and 60% of Neotropical insects. These bacteria are responsible for reproductive phenomena such as cytoplasmic incompatibility, male killing, feminization and parthenogenesis. Supergroups A and B of Wolbachia are common in insects and can be identified using primers for 16S rDNA, ftsZ and wsp; these primers vary in their ability to detect Wolbachia. The ftsZ primer was the first primer used to detect Wolbachia in Anastrepha fruit flies. The primers for 16S rDNA, ftsZ and wsp and the corresponding PCR conditions have been optimized to study the distribution of Wolbachia and their effect on the biology of Anastrepha in Brazil. In this work, we examined the ability of these primers to detect Wolbachia in Anastrepha populations from three regions in the State of São Paulo, southeastern Brazil. All of the samples were positive for Wolbachia supergroup A when screened with primers for 16S A rDNA and wsp A; the wsp B primer also gave a positive result, indicating cross-reactivity. The ftsZ primer showed a poor ability to detect Wolbachia in Anastrepha and generated false negatives in 44.9% of the samples. These findings indicate that reliable PCR detection of Wolbachia requires the use of primers for 16S rDNA and wsp to avoid cross-reactions and false negatives, and that the ftsZ primer needs to be redesigned to improve its selectivity. PMID:24031693

  1. Open release of male mosquitoes infected with a wolbachia biopesticide: field performance and infection containment.

    PubMed

    O'Connor, Linda; Plichart, Catherine; Sang, Ayo Cheong; Brelsfoard, Corey L; Bossin, Hervé C; Dobson, Stephen L

    2012-01-01

    Lymphatic filariasis (LF) is a globally significant disease, with 1.3 billion persons in 83 countries at risk. A coordinated effort of administering annual macrofilaricidal prophylactics to the entire at-risk population has succeeded in impacting and eliminating LF transmission in multiple regions. However, some areas in the South Pacific are predicted to persist as transmission sites, due in part to the biology of the mosquito vector, which has led to a call for additional tools to augment drug treatments. Autocidal strategies against mosquitoes are resurging in the effort against invasive mosquitoes and vector borne disease, with examples that include field trials of genetically modified mosquitoes and Wolbachia population replacement. However, critical questions must be addressed in anticipation of full field trials, including assessments of field competitiveness of transfected males and the risk of unintended population replacement. We report the outcome of field experiments testing a strategy that employs Wolbachia as a biopesticide. The strategy is based upon Wolbachia-induced conditional sterility, known as cytoplasmic incompatibility, and the repeated release of incompatible males to suppress a population. A criticism of the Wolbachia biopesticide approach is that unintended female release or horizontal Wolbachia transmission can result in population replacement instead of suppression. We present the outcome of laboratory and field experiments assessing the competitiveness of transfected males and their ability to transmit Wolbachia via horizontal transmission. The results demonstrate that Wolbachia-transfected Aedes polynesiensis males are competitive under field conditions during a thirty-week open release period, as indicated by mark, release, recapture and brood-hatch failure among females at the release site. Experiments demonstrate the males to be 'dead end hosts' for Wolbachia and that methods were adequate to prevent population replacement at the

  2. Wolbachia infection status and genetic structure in natural populations of Polytremis nascens (Lepidoptera: Hesperiidae).

    PubMed

    Jiang, Weibin; Zhu, Jianqing; Chen, Minghan; Yang, Qichang; Du, Xuan; Chen, Shiyan; Zhang, Lina; Yu, Yiming; Yu, Weidong

    2014-10-01

    The maternally inherited obligate bacteria Wolbachia is known for infecting the reproductive tissues of a wide range of arthropods. In this study, we surveyed Wolbachia infections in Polytremis nascens (Lepidoptera: Hesperiidae) from 14 locations in China by amplifying the 16S rRNA gene with a nested PCR method and revealed the effect of Wolbachia on host mitochondrial DNA. The results show that 31% (21/67) are Wolbachia positive among all specimens and mainly prevails in southern populations in China. No significant difference in the prevalence is found between the sexes. Notably, the nucleotide diversity of Wolbachia infected butterflies is smaller compared to that of uninfected butterflies. The mitochondrial DNA of infected group appear to be not evolving neutrally (Tajima's D value=-2.3303 and Fu's F values=-3.7068). The analysis of molecular variance shows significant differentiation of mitochondrial haplotypes between infected and uninfected specimens (FST=0.6064). The mismatch analysis speculated the different expansion pattern in Wolbachia infected specimens and all P. nascens specimens. These results suggest that the populations of P. nascens may have recently been subjected to a Wolbachia-induced sweep. Additionally, phylogenetic analysis differentiated the mitochondrial haplotypes of P. nascens into three major clades. The clades are in perfect agreement with the pattern of Wolbachia infection. One of the clades grouped with the butterflies infected with Wolbachia. The remaining two clades grouped with uninfected butterflies from the central-west of China populations and Eastern and Southern China populations respectively, which are isolated mainly by the Yangtze River. The analysis of haplotype networks, geographic distribution and population size change shows that Haplotype 1 in central-west of China is the ancestral haplotype and the populations of P. nascens are expanded.

  3. Mechanisms of Horizontal Cell-to-Cell Transfer of Wolbachia spp. in Drosophila melanogaster.

    PubMed

    White, Pamela M; Pietri, Jose E; Debec, Alain; Russell, Shelbi; Patel, Bhavin; Sullivan, William

    2017-04-01

    Wolbachia is an intracellular endosymbiont present in most arthropod and filarial nematode species. Transmission between hosts is primarily vertical, taking place exclusively through the female germ line, although horizontal transmission has also been documented. The results of several studies indicate that Wolbachia spp. can undergo transfer between somatic and germ line cells during nematode development and in adult flies. However, the mechanisms underlying horizontal cell-to-cell transfer remain largely unexplored. Here, we establish a tractable system for probing horizontal transfer of Wolbachia cells between Drosophila melanogaster cells in culture using fluorescence in situ hybridization (FISH). First, we show that horizontal transfer is independent of cell-to-cell contact and can efficiently take place through the culture medium within hours. Further, we demonstrate that efficient transfer utilizes host cell phagocytic and clathrin/dynamin-dependent endocytic machinery. Lastly, we provide evidence that this process is conserved between species, showing that horizontal transfer from mosquito to Drosophila cells takes place in a similar fashion. Altogether, our results indicate that Wolbachia utilizes host internalization machinery during infection, and this mechanism is conserved across insect species.IMPORTANCE Our work has broad implications for the control and treatment of tropical diseases. Wolbachia can confer resistance against a variety of human pathogens in mosquito vectors. Elucidating the mechanisms of horizontal transfer will be useful for efforts to more efficiently infect nonnatural insect hosts with Wolbachia as a biological control agent. Further, as Wolbachia is essential for the survival of filarial nematodes, understanding horizontal transfer might provide new approaches to treating human infections by targeting Wolbachia Finally, this work provides a key first step toward the genetic manipulation of Wolbachia.

  4. Wolbachia-Based Dengue Virus Inhibition Is Not Tissue-Specific in Aedes aegypti

    PubMed Central

    Amuzu, Hilaria E.; McGraw, Elizabeth A.

    2016-01-01

    Background Dengue fever, caused by the dengue virus (DENV), is now the most common arbovirus transmitted disease globally. One novel approach to control DENV is to use the endosymbiotic bacterium, Wolbachia pipientis, to limit DENV replication inside the primary mosquito vector, Aedes aegypti. Wolbachia that is naturally present in a range of insects reduces the capacity for viruses, bacteria, parasites and fungi to replicate inside insects. Wolbachia’s mode of action is not well understood but may involve components of immune activation or competition with pathogens for limited host resources. The strength of Wolbachia-based anti DENV effects appear to correlate with bacterial density in the whole insect and in cell culture. Here we aimed to determine whether particular tissues, especially those with high Wolbachia densities or immune activity, play a greater role in mediating the anti DENV effect. Methodology/findings Ae. aegypti mosquito lines with and without Wolbachia (Wildtype) were orally fed DENV 3 and their viral loads subsequently measured over two time points post infection in the midgut, head, salivary glands, Malpighian tubules, fat body and carcass. We did not find correlations between Wolbachia densities and DENV loads in any tissue, nor with DENV loads in salivary glands, the endpoint of infection. This is in contrast with strong positive correlations between DENV loads in a range of tissues and salivary gland loads for Wildtype mosquitoes. Lastly, there was no evidence of a heightened role for tissues with known immune function including the fat body and the Malpighian tubules in Wolbachia’s limitation of DENV. Conclusion/significance We conclude that the efficacy of DENV blocking in Wolbachia infected mosquitoes is not reliant on any particular tissue. This work therefore suggests that the mechanism of Wolbachia-based antiviral effects is either systemic or acts locally via processes that are fundamental to diverse cell types. We further

  5. Wolbachia utilize host actin for efficient maternal transmission in Drosophila melanogaster.

    PubMed

    Newton, Irene L G; Savytskyy, Oleksandr; Sheehan, Kathy B

    2015-04-01

    Wolbachia pipientis is a ubiquitous, maternally transmitted bacterium that infects the germline of insect hosts. Estimates are that Wolbachia infect nearly 40% of insect species on the planet, making it the most prevalent infection on Earth. The bacterium, infamous for the reproductive phenotypes it induces in arthropod hosts, has risen to recent prominence due to its use in vector control. Wolbachia infection prevents the colonization of vectors by RNA viruses, including Drosophila C virus and important human pathogens such as Dengue and Chikungunya. Here we present data indicating that Wolbachia utilize the host actin cytoskeleton during oogenesis for persistence within and transmission between Drosophila melanogaster generations. We show that phenotypically wild type flies heterozygous for cytoskeletal mutations in Drosophila profilin (chic(221/+) and chic(1320/+)) or villin (qua(6-396/+)) either clear a Wolbachia infection, or result in significantly reduced infection levels. This reduction of Wolbachia is supported by PCR evidence, Western blot results and cytological examination. This phenotype is unlikely to be the result of maternal loading defects, defects in oocyte polarization, or germline stem cell proliferation, as the flies are phenotypically wild type in egg size, shape, and number. Importantly, however, heterozygous mutant flies exhibit decreased total G-actin in the ovary, compared to control flies and chic(221) heterozygous mutants exhibit decreased expression of profilin. Additionally, RNAi knockdown of profilin during development decreases Wolbachia titers. We analyze evidence in support of alternative theories to explain this Wolbachia phenotype and conclude that our results support the hypothesis that Wolbachia utilize the actin skeleton for efficient transmission and maintenance within Drosophila.

  6. Wolbachia Utilize Host Actin for Efficient Maternal Transmission in Drosophila melanogaster

    PubMed Central

    Newton, Irene L. G.; Savytskyy, Oleksandr; Sheehan, Kathy B.

    2015-01-01

    Wolbachia pipientis is a ubiquitous, maternally transmitted bacterium that infects the germline of insect hosts. Estimates are that Wolbachia infect nearly 40% of insect species on the planet, making it the most prevalent infection on Earth. The bacterium, infamous for the reproductive phenotypes it induces in arthropod hosts, has risen to recent prominence due to its use in vector control. Wolbachia infection prevents the colonization of vectors by RNA viruses, including Drosophila C virus and important human pathogens such as Dengue and Chikungunya. Here we present data indicating that Wolbachia utilize the host actin cytoskeleton during oogenesis for persistence within and transmission between Drosophila melanogaster generations. We show that phenotypically wild type flies heterozygous for cytoskeletal mutations in Drosophila profilin (chic221/+ and chic1320/+) or villin (qua6-396/+) either clear a Wolbachia infection, or result in significantly reduced infection levels. This reduction of Wolbachia is supported by PCR evidence, Western blot results and cytological examination. This phenotype is unlikely to be the result of maternal loading defects, defects in oocyte polarization, or germline stem cell proliferation, as the flies are phenotypically wild type in egg size, shape, and number. Importantly, however, heterozygous mutant flies exhibit decreased total G-actin in the ovary, compared to control flies and chic221 heterozygous mutants exhibit decreased expression of profilin. Additionally, RNAi knockdown of profilin during development decreases Wolbachia titers. We analyze evidence in support of alternative theories to explain this Wolbachia phenotype and conclude that our results support the hypothesis that Wolbachia utilize the actin skeleton for efficient transmission and maintenance within Drosophila. PMID:25906062

  7. Native Wolbachia from Aedes albopictus Blocks Chikungunya Virus Infection In Cellulo

    PubMed Central

    Raquin, Vincent; Valiente Moro, Claire; Saucereau, Yoann; Tran, Florence-Hélène; Potier, Patrick; Mavingui, Patrick

    2015-01-01

    Wolbachia, a widespread endosymbiont of terrestrial arthropods, can protect its host against viral and parasitic infections, a phenotype called "pathogen blocking". However, in some cases Wolbachia may have no effect or even enhance pathogen infection, depending on the host-Wolbachia-pathogen combination. The tiger mosquito Aedes albopictus is naturally infected by two strains of Wolbachia, wAlbA and wAlbB, and is a competent vector for different arboviruses such as dengue virus (DENV) and Chikungunya virus (CHIKV). Interestingly, it was shown in some cases that Ae. albopictus native Wolbachia strains are able to inhibit DENV transmission by limiting viral replication in salivary glands, but no such impact was measured on CHIKV replication in vivo. To better understand the Wolbachia/CHIKV/Ae. albopictus interaction, we generated a cellular model using Ae. albopictus derived C6/36 cells that we infected with the wAlbB strain. Our results indicate that CHIKV infection is negatively impacted at both RNA replication and virus assembly/secretion steps in presence of wAlbB. Using FISH, we observed CHIKV and wAlbB in the same mosquito cells, indicating that the virus is still able to enter the cell in the presence of the bacterium. Further work is needed to decipher molecular pathways involved in Wolbachia-CHIKV interaction at the cellular level, but this cellular model can be a useful tool to study the mechanism behind virus blocking phenotype induced by Wolbachia. More broadly, this underlines that despite Wolbachia antiviral potential other complex interactions occur in vivo to determine mosquito vector competence in Ae. albopictus. PMID:25923352

  8. Costs of Three Wolbachia Infections on the Survival of Aedes aegypti Larvae under Starvation Conditions.

    PubMed

    Ross, Perran A; Endersby, Nancy M; Hoffmann, Ary A

    2016-01-01

    The mosquito Aedes aegypti, the principal vector of dengue virus, has recently been infected experimentally with Wolbachia: intracellular bacteria that possess potential as dengue biological control agents. Wolbachia depend on their hosts for nutrients they are unable to synthesize themselves. Consequently, competition between Wolbachia and their host for resources could reduce host fitness under the competitive conditions commonly experienced by larvae of Ae. aegypti in the field, hampering the invasion of Wolbachia into natural mosquito populations. We assess the survival and development of Ae. aegypti larvae under starvation conditions when infected with each of three experimentally-generated Wolbachia strains: wMel, wMelPop and wAlbB, and compare their fitness to wild-type uninfected larvae. We find that all three Wolbachia infections reduce the survival of larvae relative to those that are uninfected, and the severity of the effect is concordant with previously characterized fitness costs to other life stages. We also investigate the ability of larvae to recover from extended food deprivation and find no effect of Wolbachia on this trait. Aedes aegypti larvae of all infection types were able to resume their development after one month of no food, pupate rapidly, emerge at a large size, and exhibit complete cytoplasmic incompatibility and maternal transmission. A lowered ability of Wolbachia-infected larvae to survive under starvation conditions will increase the threshold infection frequency required for Wolbachia to establish in highly competitive natural Ae. aegypti populations and will also reduce the speed of invasion. This study also provides insights into survival strategies of larvae when developing in stressful environments.

  9. Modelling the transmission dynamics of dengue in the presence of Wolbachia.

    PubMed

    Ndii, Meksianis Z; Hickson, R I; Allingham, David; Mercer, G N

    2015-04-01

    Use of the bacterium Wolbachia is an innovative new strategy designed to break the cycle of dengue transmission. There are two main mechanisms by which Wolbachia could achieve this: by reducing the level of dengue virus in the mosquito and/or by shortening the host mosquito's lifespan. However, although Wolbachia shortens the lifespan, it also gives a breeding advantage which results in complex population dynamics. This study focuses on the development of a mathematical model to quantify the effect on human dengue cases of introducing Wolbachia into the mosquito population. The model consists of a compartment-based system of first-order differential equations; seasonal forcing in the mosquito population is introduced through the adult mosquito death rate. The analysis focuses on a single dengue outbreak typical of a region with a strong seasonally-varying mosquito population. We found that a significant reduction in human dengue cases can be obtained provided that Wolbachia-carrying mosquitoes persist when competing with mosquitoes without Wolbachia. Furthermore, using the Wolbachia strain WMel reduces the mosquito lifespan by at most 10% and allows them to persist in competition with non-Wolbachia-carrying mosquitoes. Mosquitoes carrying the WMelPop strain, however, are not likely to persist as it reduces the mosquito lifespan by up to 50%. When all other effects of Wolbachia on the mosquito physiology are ignored, cytoplasmic incompatibility alone results in a reduction in the number of human dengue cases. A sensitivity analysis of the parameters in the model shows that the transmission probability, the biting rate and the average adult mosquito death rate are the most important parameters for the outcome of the cumulative proportion of human individuals infected with dengue. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Extreme Divergence of Wolbachia Tropism for the Stem-Cell-Niche in the Drosophila Testis

    PubMed Central

    Toomey, Michelle E.; Frydman, Horacio M.

    2014-01-01

    Microbial tropism, the infection of specific cells and tissues by a microorganism, is a fundamental aspect of host-microbe interactions. The intracellular bacteria Wolbachia have a peculiar tropism for the stem cell niches in the Drosophila ovary, the microenvironments that support the cells producing the eggs. The molecular underpinnings of Wolbachia stem cell niche tropism are unknown. We have previously shown that the patterns of tropism in the ovary show a high degree of conservation across the Wolbachia lineage, with closely related Wolbachia strains usually displaying the same pattern of stem cell niche tropism. It has also been shown that tropism to these structures in the ovary facilitates both vertical and horizontal transmission, providing a strong selective pressure towards evolutionary conservation of tropism. Here we show great disparity in the evolutionary conservation and underlying mechanisms of stem cell niche tropism between male and female gonads. In contrast to females, niche tropism in the male testis is not pervasive, present in only 45% of niches analyzed. The patterns of niche tropism in the testis are not evolutionarily maintained across the Wolbachia lineage, unlike what was shown in the females. Furthermore, hub tropism does not correlate with cytoplasmic incompatibility, a Wolbachia-driven phenotype imprinted during spermatogenesis. Towards identifying the molecular mechanism of hub tropism, we performed hybrid analyses of Wolbachia strains in non-native hosts. These results indicate that both Wolbachia and host derived factors play a role in the targeting of the stem cell niche in the testis. Surprisingly, even closely related Wolbachia strains in Drosophila melanogaster, derived from a single ancestor only 8,000 years ago, have significantly different tropisms to the hub, highlighting that stem cell niche tropism is rapidly diverging in males. These findings provide a powerful system to investigate the mechanisms and evolution of

  11. Experimental evolution reveals habitat-specific fitness dynamics among Wolbachia clades in Drosophila melanogaster

    PubMed Central

    Versace, Elisabetta; Nolte, Viola; Pandey, Ram Vinay; Tobler, Ray; Schlötterer, Christian

    2014-01-01

    The diversity and infection dynamics of the endosymbiont Wolbachia can be influenced by many factors, such as transmission rate, cytoplasmic incompatibility, environment, selection and genetic drift. The interplay of these factors in natural populations can result in heterogeneous infection patterns with substantial differences between populations and strains. The causes of these heterogeneities are not yet understood, partly due to the complexity of natural environments. We present experimental evolution as a new approach to study Wolbachia infection dynamics in replicate populations exposed to a controlled environment. A natural Drosophila melanogaster population infected with strains of Wolbachia belonging to different clades evolved in two laboratory environments (hot and cold) for 1.5 years. In both treatments, the rate of Wolbachia infection increased until fixation. In the hot environment, the relative frequency of different Wolbachia clades remained stable over 37 generations. In the cold environment, however, we observed marked changes in the composition of the Wolbachia population: within 15 generations, one Wolbachia clade increased more than 50% in frequency, whereas the other two clades decreased in frequency, resulting in the loss of one clade. The frequency change was highly reproducible not only among replicates, but also when flies that evolved for 42 generations in the hot environment were transferred to the cold environment. These results document how environmental factors can affect the composition of Wolbachia in D. melanogaster. The high reproducibility of the pattern suggests that experimental evolution studies can efficiently determine the functional basis of habitat-specific fitness among Wolbachia strains. PMID:24387805

  12. The mitochondrial heat shock protein 60 (HSP60) is up-regulated in Onchocerca volvulus after the depletion of Wolbachia.

    PubMed

    Pfarr, K M; Heider, U; Schmetz, C; Büttner, D W; Hoerauf, A

    2008-04-01

    Wolbachia, a genus of endosymbiotic bacteria of filarial worms, represent novel targets for anti-filarial therapy. The efficacy of compounds against Wolbachia has been evaluated using antiserum raised against the 60 kDa heat shock protein (HSP60) which binds specifically to this protein in both Wolbachia and mitochondria. It has been shown that Wolbachia stains (using such specific probes) stronger than the mitochondria in untreated Onchocerca volvulus, whereas after the depletion of Wolbachia (with drugs) staining of the mitochondria is increased. Herein, immunogold electron microscopy showed that specific anti-HSP60 serum specifically labelled Wolbachia and filarial mitochondria, and that both have distinct localization patterns, thus allowing them to be differentiated. Immunohistochemistry of O. volvulus showed that HSP60 staining is increased in the mitochondria after Wolbachia depletion in the hypodermis, epithelia, muscles, oocytes, embryos, and developing spermatozoa. This could have been the result of the antiserum preferentially binding to the Wolbachia when they are present or due to increased expression of the protein in the absence of the bacteria. To address this, mRNA levels of filarial hsp60 in O. volvulus were measured. After the depletion of Wolbachia, the transcription of hsp60 was significantly greater (7.7 fold) compared with untreated worms. We hypothesize that the increased expression of HSP60 in the absence of Wolbachia is due to a disruption of the homeostasis of the endosymbiosis.

  13. Distribution and molecular characterization of Wolbachia endosymbionts and filarial nematodes in Maryland populations of the lone star tick (Amblyomma americanum).

    PubMed

    Zhang, Xing; Norris, Douglas E; Rasgon, Jason L

    2011-07-01

    The lone star tick Amblyomma americanum is host to a wide diversity of endosymbiotic bacteria. We identified a novel Wolbachia symbiont infecting A. americanum. Multilocus sequence typing phylogenetically placed the endosymbiont in the increasingly diverse F supergroup. We assayed a total of 1031 ticks (119 females, 78 males and 834 nymphs in 89 pools) from 16 Maryland populations for infection. Infection frequencies in the natural populations were approximately 5% in females and <2% (minimum infection rate) in nymphs; infection was not detected in males. Infected populations were only observed in southern Maryland, suggesting the possibility that Wolbachia is currently invading Maryland A. americanum populations. Because F supergroup Wolbachia have been detected previously in filarial nematodes, tick samples were assayed for nematodes by PCR. Filarial nematodes were detected in 70% and 9% of Wolbachia-positive and Wolbachia-negative tick samples, respectively. While nematodes were more common in Wolbachia-positive tick samples, the lack of a strict infection concordance (Wolbachia-positive, nematode-negative and Wolbachia-negative, nematode-positive ticks) suggests that Wolbachia prevalence in ticks is not due to nematode infection. Supporting this hypothesis, phylogenetic analysis indicated that the nematodes were likely a novel species within the genus Acanthocheilonema, which has been previously shown to be Wolbachia-free. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  14. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  15. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  16. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  17. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  18. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  19. New Insights into the Evolution of Wolbachia Infections in Filarial Nematodes Inferred from a Large Range of Screened Species

    PubMed Central

    Barbuto, Michela; Martin, Coralie; Lo, Nathan; Uni, Shigehiko; Landmann, Frederic; Baccei, Sara G.; Guerrero, Ricardo; de Souza Lima, Sueli; Bandi, Claudio; Wanji, Samuel; Diagne, Moustapha; Casiraghi, Maurizio

    2011-01-01

    Background Wolbachia are intriguing symbiotic endobacteria with a peculiar host range that includes arthropods and a single nematode family, the Onchocercidae encompassing agents of filariases. This raises the question of the origin of infection in filariae. Wolbachia infect the female germline and the hypodermis. Some evidences lead to the theory that Wolbachia act as mutualist and coevolved with filariae from one infection event: their removal sterilizes female filariae; all the specimens of a positive species are infected; Wolbachia are vertically inherited; a few species lost the symbiont. However, most data on Wolbachia and filaria relationships derive from studies on few species of Onchocercinae and Dirofilariinae, from mammals. Methodology/Principal Findings We investigated the Wolbachia distribution testing 35 filarial species, including 28 species and 7 genera and/or subgenera newly screened, using PCR, immunohistochemical staining, whole mount fluorescent analysis, and cocladogenesis analysis. (i) Among the newly screened Onchocercinae from mammals eight species harbour Wolbachia but for some of them, bacteria are absent in the hypodermis, or in variable density. (ii) Wolbachia are not detected in the pathological model Monanema martini and in 8, upon 9, species of Cercopithifilaria. (iii) Supergroup F Wolbachia is identified in two newly screened Mansonella species and in Cercopithifilaria japonica. (iv) Type F Wolbachia infect the intestinal cells and somatic female genital tract. (v) Among Oswaldofilariinae, Waltonellinae and Splendidofilariinae, from saurian, anuran and bird respectively, Wolbachia are not detected. Conclusions/Significance The absence of Wolbachia in 63% of onchocercids, notably in the ancestral Oswaldofilariinae estimated 140 mya old, the diverse tissues or specimens distribution, and a recent lateral transfer in supergroup F Wolbachia, modify the current view on the role and evolution of the endosymbiont and their hosts. Further

  20. High Levels of Multiple Infections, Recombination and Horizontal Transmission of Wolbachia in the Andricus mukaigawae (Hymenoptera; Cynipidae) Communities

    PubMed Central

    Yang, Xiao-Hui; Zhu, Dao-Hong; Liu, Zhiwei; Zhao, Ling; Su, Cheng-Yuan

    2013-01-01

    Wolbachia are maternally inherited endosymbiotic bacteria of arthropods and nematodes. In arthropods, they manipulate the reproduction of their hosts to facilitate their own spread in host populations, causing cytoplasmic incompatibility, parthenogenesis induction, feminization of genetic males and male-killing. In this study, we investigated Wolbachia infection and studied wsp (Wolbachia surface protein) sequences in three wasp species associated with the unisexual galls of A. mukaigawae with the aim of determining the transmission mode and the reason for multiple infections of Wolbachia. Frequency of Wolbachia infected populations for A. mukaigawae, Synergus japonicus (inquiline), and Torymus sp. (parasitoid) was 75%, 100%, and 100%, respectively. Multiple Wolbachia infections were detected in A. mukaigawae and S. japonicus, with 5 and 8 Wolbachia strains, respectively. The two host species shared 5 Wolbachia strains and were infected by identical strains in several locations, indicating horizontal transmission of Wolbachia. The transmission potentially takes place through gall tissues, which the larvae of both wasps feed on. Furthermore, three recombination events of Wolbachia were observed: the strains W8, W2 and W6 apparently have derived from W3 and W5a, W6 and W7, W4 and W9, respectively. W8 and W2 and their respective parental strains were detected in S. japonicus. W6 was detected with only one parent (W4) in S. japonicus; W9 was detected in Torymus sp., suggesting horizontal transmission between hosts and parasitoids. In conclusion, our research supports earlier studies that horizontal transmission of Wolbachia, a symbiont of the Rickettsiales order, may be plant-mediated or take place between hosts and parasitoids. Our research provides novel molecular evidence for multiple recombination events of Wolbachia in gall wasp communities. We suggest that genomic recombination and potential plant-mediated horizontal transmission may be attributable to the high

  1. Genomes of Candidatus Wolbachia bourtzisii wDacA and Candidatus Wolbachia pipientis wDacB from the Cochineal Insect Dactylopius coccus (Hemiptera: Dactylopiidae)

    PubMed Central

    Ramírez-Puebla, Shamayim T.; Ormeño-Orrillo, Ernesto; Vera-Ponce de León, Arturo; Lozano, Luis; Sanchez-Flores, Alejandro; Rosenblueth, Mónica; Martínez-Romero, Esperanza

    2016-01-01

    Dactylopius species, known as cochineal insects, are the source of the carminic acid dye used worldwide. The presence of two Wolbachia strains in Dactylopius coccus from Mexico was revealed by PCR amplification of wsp and sequencing of 16S rRNA genes. A metagenome analysis recovered the genome sequences of Candidatus Wolbachia bourtzisii wDacA (supergroup A) and Candidatus Wolbachia pipientis wDacB (supergroup B). Genome read coverage, as well as 16S rRNA clone sequencing, revealed that wDacB was more abundant than wDacA. The strains shared similar predicted metabolic capabilities that are common to Wolbachia, including riboflavin, ubiquinone, and heme biosynthesis, but lacked other vitamin and cofactor biosynthesis as well as glycolysis, the oxidative pentose phosphate pathway, and sugar uptake systems. A complete tricarboxylic acid cycle and gluconeogenesis were predicted as well as limited amino acid biosynthesis. Uptake and catabolism of proline were evidenced in Dactylopius Wolbachia strains. Both strains possessed WO-like phage regions and type I and type IV secretion systems. Several efflux systems found suggested the existence of metal toxicity within their host. Besides already described putative virulence factors like ankyrin domain proteins, VlrC homologs, and patatin-like proteins, putative novel virulence factors related to those found in intracellular pathogens like Legionella and Mycobacterium are highlighted for the first time in Wolbachia. Candidate genes identified in other Wolbachia that are likely involved in cytoplasmic incompatibility were found in wDacB but not in wDacA. PMID:27543297

  2. Genomes of Candidatus Wolbachia bourtzisii wDacA and Candidatus Wolbachia pipientis wDacB from the Cochineal Insect Dactylopius coccus (Hemiptera: Dactylopiidae).

    PubMed

    Ramírez-Puebla, Shamayim T; Ormeño-Orrillo, Ernesto; Vera-Ponce de León, Arturo; Lozano, Luis; Sanchez-Flores, Alejandro; Rosenblueth, Mónica; Martínez-Romero, Esperanza

    2016-10-13

    Dactylopius species, known as cochineal insects, are the source of the carminic acid dye used worldwide. The presence of two Wolbachia strains in Dactylopius coccus from Mexico was revealed by PCR amplification of wsp and sequencing of 16S rRNA genes. A metagenome analysis recovered the genome sequences of Candidatus Wolbachia bourtzisii wDacA (supergroup A) and Candidatus Wolbachia pipientis wDacB (supergroup B). Genome read coverage, as well as 16S rRNA clone sequencing, revealed that wDacB was more abundant than wDacA. The strains shared similar predicted metabolic capabilities that are common to Wolbachia, including riboflavin, ubiquinone, and heme biosynthesis, but lacked other vitamin and cofactor biosynthesis as well as glycolysis, the oxidative pentose phosphate pathway, and sugar uptake systems. A complete tricarboxylic acid cycle and gluconeogenesis were predicted as well as limited amino acid biosynthesis. Uptake and catabolism of proline were evidenced in Dactylopius Wolbachia strains. Both strains possessed WO-like phage regions and type I and type IV secretion systems. Several efflux systems found suggested the existence of metal toxicity within their host. Besides already described putative virulence factors like ankyrin domain proteins, VlrC homologs, and patatin-like proteins, putative novel virulence factors related to those found in intracellular pathogens like Legionella and Mycobacterium are highlighted for the first time in Wolbachia Candidate genes identified in other Wolbachia that are likely involved in cytoplasmic incompatibility were found in wDacB but not in wDacA.

  3. Analysis of bus passenger comfort perception based on passenger load factor and in-vehicle time.

    PubMed

    Shen, Xianghao; Feng, Shumin; Li, Zhenning; Hu, Baoyu

    2016-01-01

    Although bus comfort is a crucial indicator of service quality, existing studies tend to focus on passenger load and ignore in-vehicle time, which can also affect passengers' comfort perception. Therefore, by conducting surveys, this study examines passengers' comfort perception while accounting for both factors. Then, using the survey data, it performs a two-way analysis of variance and shows that both in-vehicle time and passenger load significantly affect passenger comfort. Then, a bus comfort model is proposed to evaluate comfort level, followed by a sensitivity analysis. The method introduced in this study has theoretical implications for bus operators attempting to improve bus service quality.

  4. 14 CFR 91.1035 - Passenger awareness.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Passenger awareness. 91.1035 Section 91.1035 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... Operations Program Management § 91.1035 Passenger awareness. (a) Prior to each takeoff, the pilot in...

  5. 14 CFR 91.1035 - Passenger awareness.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Passenger awareness. 91.1035 Section 91.1035 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... Operations Program Management § 91.1035 Passenger awareness. (a) Prior to each takeoff, the pilot in...

  6. 14 CFR 91.1035 - Passenger awareness.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Passenger awareness. 91.1035 Section 91.1035 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... Operations Program Management § 91.1035 Passenger awareness. (a) Prior to each takeoff, the pilot in...

  7. Passenger and Naturalization Lists: The New Sources.

    ERIC Educational Resources Information Center

    Filby, P. William

    1983-01-01

    Reviews information sources designed to assist the genealogical researcher with the arrival of his/her ancestors: "A Bibliography of Ship Passenger Lists 1538-1825"; "Passenger and Immigration Lists Index"; "Philadelphia Naturalization Records." Examples provided include name entry, source citation, annotation, and…

  8. Airline policy relating to passengers with epilepsy.

    PubMed

    Mumford, C J; Warlow, C P

    1995-12-01

    To identify the policy of international airlines for the carriage of passengers with epilepsy. Postal questionnaire asking about policy for epileptic passengers, training of cabin crew, onboard drugs suitable for the treatment of seizures, and details of any problems reported by crews as a result of in-flight passenger seizures. The questionnaire was addressed to the medical advisors of 42 international airlines. Thirty (71%) of 42 airlines responded. Eleven (37%) of the 30 airlines that responded had a stated policy or restriction on the carriage of passengers with epilepsy. Five of these airlines advised increasing the dose of anticonvulsant drugs before travel. One airline insisted that epileptic passengers travel with a companion. Twenty-five (83%) of 30 airlines dealt specifically with epilepsy in the training program of their cabin crews. Seventeen (57%) of 30 airlines carried diazepam onboard, mostly in injectable form. Most airlines reported no, or very few, incidents of in-flight passenger seizures annually. The advice offered to intending epileptic passengers differs greatly between airlines. Some airlines instruct intending passengers to increase their regular medication, probably without justification, since in-flight seizures are very infrequent. Training of cabin crew and the medical equipment carried onboard also vary and in some cases are inadequate.

  9. Influential input classification in probabilistic multimedia models

    SciTech Connect

    Maddalena, Randy L.; McKone, Thomas E.; Hsieh, Dennis P.H.; Geng, Shu

    1999-05-01

    Monte Carlo analysis is a statistical simulation method that is often used to assess and quantify the outcome variance in complex environmental fate and effects models. Total outcome variance of these models is a function of (1) the uncertainty and/or variability associated with each model input and (2) the sensitivity of the model outcome to changes in the inputs. To propagate variance through a model using Monte Carlo techniques, each variable must be assigned a probability distribution. The validity of these distributions directly influences the accuracy and reliability of the model outcome. To efficiently allocate resources for constructing distributions one should first identify the most influential set of variables in the model. Although existing sensitivity and uncertainty analysis methods can provide a relative ranking of the importance of model inputs, they fail to identify the minimum set of stochastic inputs necessary to sufficiently characterize the outcome variance. In this paper, we describe and demonstrate a novel sensitivity/uncertainty analysis method for assessing the importance of each variable in a multimedia environmental fate model. Our analyses show that for a given scenario, a relatively small number of input variables influence the central tendency of the model and an even smaller set determines the shape of the outcome distribution. For each input, the level of influence depends on the scenario under consideration. This information is useful for developing site specific models and improving our understanding of the processes that have the greatest influence on the variance in outcomes from multimedia models.

  10. Train Timetable Evaluation from the Viewpoints of Passengers by Microsimulation of Train Operation and Passenger Flow

    NASA Astrophysics Data System (ADS)

    Kunimatsu, Taketoshi; Hirai, Chikara; Tomii, Norio

    In order to evaluate train timetables from passengers' points of view, it is indispensable to estimate the disutilities of passengers. This can be done by estimating the movements of passengers and trains accurately. In particular, when there are many passengers, an interaction between the passengers and trains must be considered. To this end, we have developed a microsimulation system to simulate both train operation and passengers' train choice behavior. The system can simulate train choice behaviors of more than one million passengers as well as their positions in trains. It is possible to estimate the delays caused by congestion in trains as well. The system is based on models of different attitudes of the passengers with respect to the train choice behavior, with includes the choice of the earliest train, transfer avoidance, and congestion avoidance; a passengers' train choice behavior reflects his/her preferences. We applied this system to an actual railway line in a metropolitan area and evaluated two train schedules by calculating the generalized cost that reflects each passenger's disutility in his/her experience. Through the numerical experiments, we have confirmed that the proposed method is very useful for evaluating timetables from passengers' points of view.

  11. Content Analysis of the 20 Most Influential Articles in "PIQ"

    ERIC Educational Resources Information Center

    Cho, Yonjoo; Park, Sunyoung

    2012-01-01

    The purpose of this study is to examine key research themes in human performance technology (HPT) through content analysis of the 20 most influential articles identified in Cho, Jo, Park, Kang, and Chen (2011). Three questions guiding this inquiry are: (1) What are the key themes of the 20 most influential articles in "PIQ", (2) What information…

  12. Content Analysis of the 20 Most Influential Articles in "PIQ"

    ERIC Educational Resources Information Center

    Cho, Yonjoo; Park, Sunyoung

    2012-01-01

    The purpose of this study is to examine key research themes in human performance technology (HPT) through content analysis of the 20 most influential articles identified in Cho, Jo, Park, Kang, and Chen (2011). Three questions guiding this inquiry are: (1) What are the key themes of the 20 most influential articles in "PIQ", (2) What information…

  13. A novel approach to eliminate Wolbachia infections in Nasonia vitripennis revealed different antibiotic resistance between two bacterial strains.

    PubMed

    Liu, Hai-Yang; Wang, Yan-Kun; Zhi, Cong-Cong; Xiao, Jin-Hua; Huang, Da-Wei

    2014-06-01

    Wolbachia are widespread in insects and can manipulate host reproduction. Nasonia vitripennis is a widely studied organism with a very high prevalence of Wolbachia infection. To study the effect of Wolbachia infection in Nasonia spp., it is important to obtain noninfected individuals by artificial methods. Current methods that employ sugar water-containing antibiotics can successfully eliminate Wolbachia from the parasitic wasps; however, treatment of at least three generations is required. Here, we describe a novel, feasible, and effective approach to eliminate Wolbachia from N. vitripennis by feeding fly pupae continuously offering antibiotics to Nasonia populations, which shortened the time to eliminate the pathogens to two generations. Additionally, the Wolbachia Uni and CauB strains have obviously different rifampicin-resistance abilities, which is a previously unknown phenomenon.

  14. Eukaryotic association module in phage WO genomes from Wolbachia

    PubMed Central

    Bordenstein, Sarah R.; Bordenstein, Seth R.

    2016-01-01

    Viruses are trifurcated into eukaryotic, archaeal and bacterial categories. This domain-specific ecology underscores why eukaryotic viruses typically co-opt eukaryotic genes and bacteriophages commonly harbour bacterial genes. However, the presence of bacteriophages in obligate intracellular bacteria of eukaryotes may promote DNA transfers between eukaryotes and bacteriophages. Here we report a metagenomic analysis of purified bacteriophage WO particles of Wolbachia and uncover a eukaryotic association module in the complete WO genome. It harbours predicted domains, such as the black widow latrotoxin C-terminal domain, that are uninterrupted in bacteriophage genomes, enriched with eukaryotic protease cleavage sites and combined with additional domains to forge one of the largest bacteriophage genes to date (14,256 bp). To the best of our knowledge, these eukaryotic-like domains have never before been reported in packaged bacteriophages and their phylogeny, distribution and sequence diversity imply lateral transfers between bacteriophage/prophage and animal genomes. Finally, the WO genome sequences and identification of attachment sites will potentially advance genetic manipulation of Wolbachia. PMID:27727237

  15. Eukaryotic association module in phage WO genomes from Wolbachia.

    PubMed

    Bordenstein, Sarah R; Bordenstein, Seth R

    2016-10-11

    Viruses are trifurcated into eukaryotic, archaeal and bacterial categories. This domain-specific ecology underscores why eukaryotic viruses typically co-opt eukaryotic genes and bacteriophages commonly harbour bacterial genes. However, the presence of bacteriophages in obligate intracellular bacteria of eukaryotes may promote DNA transfers between eukaryotes and bacteriophages. Here we report a metagenomic analysis of purified bacteriophage WO particles of Wolbachia and uncover a eukaryotic association module in the complete WO genome. It harbours predicted domains, such as the black widow latrotoxin C-terminal domain, that are uninterrupted in bacteriophage genomes, enriched with eukaryotic protease cleavage sites and combined with additional domains to forge one of the largest bacteriophage genes to date (14,256 bp). To the best of our knowledge, these eukaryotic-like domains have never before been reported in packaged bacteriophages and their phylogeny, distribution and sequence diversity imply lateral transfers between bacteriophage/prophage and animal genomes. Finally, the WO genome sequences and identification of attachment sites will potentially advance genetic manipulation of Wolbachia.

  16. Hindrances to bistable front propagation: application to Wolbachia invasion.

    PubMed

    Nadin, Grégoire; Strugarek, Martin; Vauchelet, Nicolas

    2017-09-22

    We study the biological situation when an invading population propagates and replaces an existing population with different characteristics. For instance, this may occur in the presence of a vertically transmitted infection causing a cytoplasmic effect similar to the Allee effect (e.g. Wolbachia in Aedes mosquitoes): the invading dynamics we model is bistable. We aim at quantifying the propagules (what does it take for an invasion to start?) and the invasive power (how far can an invading front go, and what can stop it?). We rigorously show that a heterogeneous environment inducing a strong enough population gradient can stop an invading front, which will converge in this case to a stable front. We characterize the critical population jump, and also prove the existence of unstable fronts above the stable (blocking) fronts. Being above the maximal unstable front enables an invading front to clear the obstacle and propagate further. We are particularly interested in the case of artificial Wolbachia infection, used as a tool to fight arboviruses.

  17. Taxonomic status of the intracellular bacterium Wolbachia pipientis.

    PubMed

    Lo, N; Paraskevopoulos, C; Bourtzis, K; O'Neill, S L; Werren, J H; Bordenstein, S R; Bandi, C

    2007-03-01

    Wolbachia pipientis is a maternally inherited, intracellular bacterium found in more than 20 % of all insects, as well as numerous other arthropods and filarial nematodes. It has been the subject of a growing number of studies in recent decades, because of the remarkable effects it has on its arthropod hosts, its potential as a tool for biological control of arthropods of agricultural and medical importance and its use as a target for treatment of filariasis. W. pipientis was originally discovered in cells of the mosquito Culex pipiens and is the only formally described member of the genus. Molecular sequence-based studies have revealed a number of phylogenetically diverse strains of W. pipientis. Owing to uncertainty about whether W. pipientis comprises more than one species, researchers in the field now commonly refer to W. pipientis simply as Wolbachia. In this note, we briefly review higher-level phylogenetic and recombination studies of W. pipientis and propose that all the intracellular symbionts known to cluster closely with the type strain of W. pipientis, including those in the currently recognized supergroups (A-H), are officially given this name.

  18. Evidence for Metabolic Provisioning by a Common Invertebrate Endosymbiont, Wolbachia pipientis, during Periods of Nutritional Stress

    PubMed Central

    Brownlie, Jeremy C.; Cass, Bodil N.; Riegler, Markus; Witsenburg, Joris J.; Iturbe-Ormaetxe, Iñaki; McGraw, Elizabeth A.; O'Neill, Scott L.

    2009-01-01

    Wolbachia are ubiquitous inherited endosymbionts of invertebrates that invade host populations by modifying host reproductive systems. However, some strains lack the ability to impose reproductive modification and yet are still capable of successfully invading host populations. To explain this paradox, theory predicts that such strains should provide a fitness benefit, but to date none has been detected. Recently completed genome sequences of different Wolbachia strains show that these bacteria may have the genetic machinery to influence iron utilization of hosts. Here we show that Wolbachia infection can confer a positive fecundity benefit for Drosophila melanogaster reared on iron-restricted or -overloaded diets. Furthermore, iron levels measured from field-collected flies indicated that nutritional conditions in the field were overall comparable to those of flies reared in the laboratory on restricted diets. These data suggest that Wolbachia may play a previously unrecognized role as nutritional mutualists in insects. PMID:19343208

  19. Wolbachia Blocks Currently Circulating Zika Virus Isolates in Brazilian Aedes aegypti Mosquitoes.

    PubMed

    Dutra, Heverton Leandro Carneiro; Rocha, Marcele Neves; Dias, Fernando Braga Stehling; Mansur, Simone Brutman; Caragata, Eric Pearce; Moreira, Luciano Andrade

    2016-06-08

    The recent association of Zika virus with cases of microcephaly has sparked a global health crisis and highlighted the need for mechanisms to combat the Zika vector, Aedes aegypti mosquitoes. Wolbachia pipientis, a bacterial endosymbiont of insect, has recently garnered attention as a mechanism for arbovirus control. Here we report that Aedes aegypti harboring Wolbachia are highly resistant to infection with two currently circulating Zika virus isolates from the recent Brazilian epidemic. Wolbachia-harboring mosquitoes displayed lower viral prevalence and intensity and decreased disseminated infection and, critically, did not carry infectious virus in the saliva, suggesting that viral transmission was blocked. Our data indicate that the use of Wolbachia-harboring mosquitoes could represent an effective mechanism to reduce Zika virus transmission and should be included as part of Zika control strategies. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  20. Wolbachia Infections Responsible for Thelytoky in Dryinid Wasps. The Case of Gonatopus bonaerensis Virla (Hymenoptera: Dryinidae).

    PubMed

    Espinosa, M S; Virla, E G; Cuozzo, S

    2017-08-01

    We studied the occurrence of Wolbachia in the parasitoid Gonatopus bonaerensis Virla (Hymenoptera: Dryinidae). In order to verify the existence of natural infections in the parasitoid, a field survey was conducted. Identification of Wolbachia was performed on the basis of 16S rDNA, wsp_F1, and wsp_R1-sequences. After the detection of the bacteria, infected specimens of G. bonaerensis were treated with a solution of tetracycline. In Tucumán, parasitoids hold Wolbachia endosymbiont, which seems to control the wasp's reproduction in the nature turning it into thelytokous. The symbiont was identified as the Wolbachia sp. wRi strain. The cure of infected unfertilized females determined the normal arrhenotokous parthenogenesis and the production of male offspring. As a consequence of this procedure, the male of G. bonaerensis is described for the first time.

  1. Wolbachia Do Not Induce Reactive Oxygen Species-Dependent Immune Pathway Activation in Aedes albopictus

    PubMed Central

    Molloy, Jennifer C.; Sinkins, Steven P.

    2015-01-01

    Aedes albopictus is a major vector of dengue (DENV) and chikungunya (CHIKV) viruses, causing millions of infections annually. It naturally carries, at high frequency, the intracellular inherited bacterial endosymbiont Wolbachia strains wAlbA and wAlbB; transinfection with the higher-density Wolbachia strain wMel from Drosophila melanogaster led to transmission blocking of both arboviruses. The hypothesis that reactive oxygen species (ROS)-induced immune activation plays a role in arbovirus inhibition in this species was examined. In contrast to previous observations in Ae. aegypti, elevation of ROS levels was not observed in either cell lines or mosquito lines carrying the wild-type Wolbachia or higher-density Drosophila Wolbachia strains. There was also no upregulation of genes controlling innate immune pathways or with antioxidant/ROS-producing functions. These data suggest that ROS-mediated immune activation is not an important component of the viral transmission-blocking phenotype in this species. PMID:26287231

  2. Tsetse-Wolbachia symbiosis: Comes of age and has great potential for pest and disease control

    PubMed Central

    Doudoumis, Vangelis; Alam, Uzma; Aksoy, Emre; Abd-Alla, Adly M.M.; Tsiamis, George; Brelsfoard, Corey; Aksoy, Serap; Bourtzis, Kostas

    2013-01-01

    Tsetse flies (Diptera: Glossinidae) are the sole vectors of African trypanosomes, the causative agent of sleeping sickness in human and nagana in animals. Like most eukaryotic organisms, Glossina species have established symbiotic associations with bacteria. Three main symbiotic bacteria have been found in tsetse flies: Wigglesworthia glossinidia, an obligate symbiotic bacterium, the secondary endosymbiont Sodalis glossinidius and the reproductive symbiont Wolbachia pipientis. In the present review, we discuss recent studies on the detection and characterization of Wolbachia infections in Glossina species, the horizontal transfer of Wolbachia genes to tsetse chromosomes, the ability of this symbiont to induce cytoplasmic incompatibility in Glossina morsitans morsitans and also how new environment-friendly tools for disease control could be developed by harnessing Wolbachia symbiosis. PMID:22835476

  3. Closely related Wolbachia (Rickettsiales:Rickettsiaceae) recovered from different genera of Mexican Thelytokous figitidae (Hymenoptera)

    USDA-ARS?s Scientific Manuscript database

    Thelytokous parasitoid strains are theoretically advantageous when utilized for biological control, as the absence of males should reduce production costs and potentially increase field efficacy. The maternally inherited intracellular bacterium, Wolbachia pipientis, is capable of inducing thelytokou...

  4. Wolbachia co-infection in a hybrid zone: discovery of horizontal gene transfers from two Wolbachia supergroups into an animal genome.

    PubMed

    Funkhouser-Jones, Lisa J; Sehnert, Stephanie R; Martínez-Rodríguez, Paloma; Toribio-Fernández, Raquel; Pita, Miguel; Bella, José L; Bordenstein, Seth R

    2015-01-01

    Hybrid zones and the consequences of hybridization have contributed greatly to our understanding of evolutionary processes. Hybrid zones also provide valuable insight into the dynamics of symbiosis since each subspecies or species brings its unique microbial symbionts, including germline bacteria such as Wolbachia, to the hybrid zone. Here, we investigate a natural hybrid zone of two subspecies of the meadow grasshopper Chorthippus parallelus in the Pyrenees Mountains. We set out to test whether co-infections of B and F Wolbachia in hybrid grasshoppers enabled horizontal transfer of phage WO, similar to the numerous examples of phage WO transfer between A and B Wolbachia co-infections. While we found no evidence for transfer between the divergent co-infections, we discovered horizontal transfer of at least three phage WO haplotypes to the grasshopper genome. Subsequent genome sequencing of uninfected grasshoppers uncovered the first evidence for two discrete Wolbachia supergroups (B and F) contributing at least 448 kb and 144 kb of DNA, respectively, into the host nuclear genome. Fluorescent in situ hybridization verified the presence of Wolbachia DNA in C. parallelus chromosomes and revealed that some inserts are subspecies-specific while others are present in both subspecies. We discuss our findings in light of symbiont dynamics in an animal hybrid zone.

  5. How Diverse Is the Genus Wolbachia? Multiple-Gene Sequencing Reveals a Putatively New Wolbachia Supergroup Recovered from Spider Mites (Acari: Tetranychidae)▿ †

    PubMed Central

    Ros, Vera I. D.; Fleming, Vicki M.; Feil, Edward J.; Breeuwer, Johannes A. J.

    2009-01-01

    At least 20% of all arthropods and some nematode species are infected with intracellular bacteria of the genus Wolbachia. This highly diverse genus has been subdivided into eight “supergroups” (A to H) on the basis of nucleotide sequence data. Here, we report the discovery of a new Wolbachia supergroup recovered from the spider mite species Bryobia species V (Acari: Tetranychidae), based on the sequences of three protein-coding genes (ftsZ, gltA, and groEL) and the 16S rRNA gene. Other tetranychid mites possess supergroup B Wolbachia strains. The discovery of another Wolbachia supergroup expands the known diversity of Wolbachia and emphasizes the high variability of the genus. Our data also clarify the existing supergroup structure and highlight the use of multiple gene sequences for robust phylogenetic analysis. In addition to previous reports of recombination between the arthropod-infecting supergroups A and B, we provide evidence for recombination between the nematode-infecting supergroups C and D. Robust delineation of supergroups is essential for understanding the origin and spread of this common reproductive parasite and for unraveling mechanisms of host adaptation and manipulation across a wide range of hosts. PMID:19098217

  6. Wolbachia co-infection in a hybrid zone: discovery of horizontal gene transfers from two Wolbachia supergroups into an animal genome

    PubMed Central

    Sehnert, Stephanie R.; Martínez-Rodríguez, Paloma; Toribio-Fernández, Raquel; Pita, Miguel; Bella, José L.; Bordenstein, Seth R.

    2015-01-01

    Hybrid zones and the consequences of hybridization have contributed greatly to our understanding of evolutionary processes. Hybrid zones also provide valuable insight into the dynamics of symbiosis since each subspecies or species brings its unique microbial symbionts, including germline bacteria such as Wolbachia, to the hybrid zone. Here, we investigate a natural hybrid zone of two subspecies of the meadow grasshopper Chorthippus parallelus in the Pyrenees Mountains. We set out to test whether co-infections of B and F Wolbachia in hybrid grasshoppers enabled horizontal transfer of phage WO, similar to the numerous examples of phage WO transfer between A and B Wolbachia co-infections. While we found no evidence for transfer between the divergent co-infections, we discovered horizontal transfer of at least three phage WO haplotypes to the grasshopper genome. Subsequent genome sequencing of uninfected grasshoppers uncovered the first evidence for two discrete Wolbachia supergroups (B and F) contributing at least 448 kb and 144 kb of DNA, respectively, into the host nuclear genome. Fluorescent in situ hybridization verified the presence of Wolbachia DNA in C. parallelus chromosomes and revealed that some inserts are subspecies-specific while others are present in both subspecies. We discuss our findings in light of symbiont dynamics in an animal hybrid zone. PMID:26664808

  7. Detection and characterization of Wolbachia infections in laboratory and natural populations of different species of tsetse flies (genus Glossina)

    PubMed Central

    2012-01-01

    Background Wolbachia is a genus of endosymbiotic α-Proteobacteria infecting a wide range of arthropods and filarial nematodes. Wolbachia is able to induce reproductive abnormalities such as cytoplasmic incompatibility (CI), thelytokous parthenogenesis, feminization and male killing, thus affecting biology, ecology and evolution of its hosts. The bacterial group has prompted research regarding its potential for the control of agricultural and medical disease vectors, including Glossina spp., which transmits African trypanosomes, the causative agents of sleeping sickness in humans and nagana in animals. Results In the present study, we employed a Wolbachia specific 16S rRNA PCR assay to investigate the presence of Wolbachia in six different laboratory stocks as well as in natural populations of nine different Glossina species originating from 10 African countries. Wolbachia was prevalent in Glossina morsitans morsitans, G. morsitans centralis and G. austeni populations. It was also detected in G. brevipalpis, and, for the first time, in G. pallidipes and G. palpalis gambiensis. On the other hand, Wolbachia was not found in G. p. palpalis, G. fuscipes fuscipes and G. tachinoides. Wolbachia infections of different laboratory and natural populations of Glossina species were characterized using 16S rRNA, the wsp (Wolbachia Surface Protein) gene and MLST (Multi Locus Sequence Typing) gene markers. This analysis led to the detection of horizontal gene transfer events, in which Wobachia genes were inserted into the tsetse flies fly nuclear genome. Conclusions Wolbachia infections were detected in both laboratory and natural populations of several different Glossina species. The characterization of these Wolbachia strains promises to lead to a deeper insight in tsetse flies-Wolbachia interactions, which is essential for the development and use of Wolbachia-based biological control methods. PMID:22376025

  8. Association of a New Wolbachia Strain with, and Its Effects on, Leptopilina victoriae, a Virulent Wasp Parasitic to Drosophila spp.

    PubMed Central

    Gueguen, Gwenaelle; Onemola, Bodunde

    2012-01-01

    Wolbachia bacteria are ubiquitous intracellular bacteria of arthropods. Often considered reproductive parasites, they can benefit certain host species. We describe a new Wolbachia strain from Leptopilina victoriae, a Drosophila wasp. The strain is closely related to Wolbachia from Culex sp. Located to the posterior poles of oocytes, it manipulates its host's reproduction by inducing a male development type of cytoplasmic incompatibility. We also report its diverse effects on the wasp's life history traits. PMID:22685158

  9. Association of a new Wolbachia strain with, and its effects on, Leptopilina victoriae, a virulent wasp parasitic to Drosophila spp.

    PubMed

    Gueguen, Gwenaelle; Onemola, Bodunde; Govind, Shubha

    2012-08-01

    Wolbachia bacteria are ubiquitous intracellular bacteria of arthropods. Often considered reproductive parasites, they can benefit certain host species. We describe a new Wolbachia strain from Leptopilina victoriae, a Drosophila wasp. The strain is closely related to Wolbachia from Culex sp. Located to the posterior poles of oocytes, it manipulates its host's reproduction by inducing a male development type of cytoplasmic incompatibility. We also report its diverse effects on the wasp's life history traits.

  10. Effect of Wolbachia on replication of West Nile virus in a mosquito cell line and adult mosquitoes.

    PubMed

    Hussain, Mazhar; Lu, Guangjin; Torres, Shessy; Edmonds, Judith H; Kay, Brian H; Khromykh, Alexander A; Asgari, Sassan

    2013-01-01

    Wolbachia as an endosymbiont is widespread in insects and other arthropods and is best known for reproductive manipulations of the host. Recently, it has been shown that wMelpop and wMel strains of Wolbachia inhibit the replication of several RNA viruses, including dengue virus, and other vector-borne pathogens (e.g., Plasmodium and filarial nematodes) in mosquitoes, providing an alternative approach to limit the transmission of vector-borne pathogens. In this study, we tested the effect of Wolbachia on the replication of West Nile Virus (WNV). Surprisingly, accumulation of the genomic RNA of WNV for all three strains of WNV tested (New York 99, Kunjin, and New South Wales) was enhanced in Wolbachia-infected Aedes aegypti cells (Aag2). However, the amount of secreted virus was significantly reduced in the presence of Wolbachia. Intrathoracic injections showed that replication of WNV in A. aegypti mosquitoes infected with wMel strain of Wolbachia was not inhibited, whereas wMelPop strain of Wolbachia significantly reduced the replication of WNV in mosquitoes. Further, when wMelPop mosquitoes were orally fed with WNV, virus infection, transmission, and dissemination rates were very low in Wolbachia-free mosquitoes and were completely inhibited in the presence of Wolbachia. The results suggest that (i) despite the enhancement of viral genomic RNA replication in the Wolbachia-infected cell line the production of secreted virus was significantly inhibited, (ii) the antiviral effect in intrathoracically infected mosquitoes depends on the strain of Wolbachia, and (iii) replication of the virus in orally fed mosquitoes was completely inhibited in wMelPop strain of Wolbachia.

  11. Wolbachia in the Drosophila yakuba Complex: Pervasive Frequency Variation and Weak Cytoplasmic Incompatibility, but No Apparent Effect on Reproductive Isolation.

    PubMed

    Cooper, Brandon S; Ginsberg, Paul S; Turelli, Michael; Matute, Daniel R

    2017-01-01

    Three hybridizing species-the clade [(Drosophila yakuba, D. santomea), D. teissieri]-comprise the yakuba complex in the D. melanogaster subgroup. Their ranges overlap on Bioko and São Tomé, islands off west Africa. All three species are infected with Wolbachia-maternally inherited, endosymbiotic bacteria, best known for manipulating host reproduction to favor infected females. Previous analyses reported no cytoplasmic incompatibility (CI) in these species. However, we discovered that Wolbachia from each species cause intraspecific and interspecific CI. In D teissieri, analyses of F1 and backcross genotypes show that both host genotype and Wolbachia variation modulate CI intensity. Wolbachia-infected females seem largely protected from intraspecific and interspecific CI, irrespective of Wolbachia and host genotypes. Wolbachia do not affect host mating behavior or female fecundity, within or between species. The latter suggests little apparent effect of Wolbachia on premating or gametic reproductive isolation (RI) between host species. In nature, Wolbachia frequencies varied spatially for D. yakuba in 2009, with 76% (N = 155) infected on São Tomé, and only 3% (N = 36) infected on Bioko; frequencies also varied temporally in D. yakuba and D. santomea on São Tomé between 2009 and 2015. These temporal frequency fluctuations could generate asymmetries in interspecific mating success, and contribute to postzygotic RI. However, the fluctuations in Wolbachia frequencies that we observe also suggest that asymmetries are unlikely to persist. Finally, we address theoretical questions that our empirical findings raise about Wolbachia persistence when conditions fluctuate, and about the stable coexistence of Wolbachia and host variants that modulate Wolbachia effects. Copyright © 2017 by the Genetics Society of America.

  12. Wolbachia influences the maternal transmission of the gypsy endogenous retrovirus in Drosophila melanogaster.

    PubMed

    Touret, Franck; Guiguen, François; Terzian, Christophe

    2014-09-02

    The endosymbiotic bacteria of the genus Wolbachia are present in most insects and are maternally transmitted through the germline. Moreover, these intracellular bacteria exert antiviral activity against insect RNA viruses, as in Drosophila melanogaster, which could explain the prevalence of Wolbachia bacteria in natural populations. Wolbachia is maternally transmitted in D. melanogaster through a mechanism that involves distribution at the posterior pole of mature oocytes and then incorporation into the pole cells of the embryos. In parallel, maternal transmission of several endogenous retroviruses is well documented in D. melanogaster. Notably, gypsy retrovirus is expressed in permissive follicle cells and transferred to the oocyte and then to the offspring by integrating into their genomes. Here, we show that the presence of Wolbachia wMel reduces the rate of gypsy insertion into the ovo gene. However, the presence of Wolbachia does not modify the expression levels of gypsy RNA and envelope glycoprotein from either permissive or restrictive ovaries. Moreover, Wolbachia affects the pattern of distribution of the retroviral particles and the gypsy envelope protein in permissive follicle cells. Altogether, our results enlarge the knowledge of the antiviral activity of Wolbachia to include reducing the maternal transmission of endogenous retroviruses in D. melanogaster. Animals have established complex relationships with bacteria and viruses that spread horizontally among individuals or are vertically transmitted, i.e., from parents to offspring. It is well established that members of the genus Wolbachia, maternally inherited symbiotic bacteria present mainly in arthropods, reduce the replication of several RNA viruses transmitted horizontally. Here, we demonstrate for the first time that Wolbachia diminishes the maternal transmission of gypsy, an endogenous retrovirus in Drosophila melanogaster. We hypothesize that gypsy cannot efficiently integrate into the germ

  13. Wolbachia do not live by reproductive manipulation alone: infection polymorphism in Drosophila suzukii and D. subpulchrella.

    PubMed

    Hamm, Christopher A; Begun, David J; Vo, Alexandre; Smith, Chris C R; Saelao, Perot; Shaver, Amanda O; Jaenike, John; Turelli, Michael

    2014-10-01

    Drosophila suzukii recently invaded North America and Europe. Populations in Hawaii, California, New York and Nova Scotia are polymorphic for Wolbachia, typically with <20% infection frequency. The Wolbachia in D. suzukii, denoted wSuz, is closely related to wRi, the variant prevalent in continental populations of D. simulans. wSuz is also nearly identical to Wolbachia found in D. subpulchrella, plausibly D. suzukii's sister species. This suggests vertical Wolbachia transmission through cladogenesis ('cladogenic transmission'). The widespread occurrence of 7-20% infection frequencies indicates a stable polymorphism. wSuz is imperfectly maternally transmitted, with wild infected females producing on average 5-10% uninfected progeny. As expected from its low frequency, wSuz produces no cytoplasmic incompatibility (CI), that is, no increased embryo mortality when infected males mate with uninfected females, and no appreciable sex-ratio distortion. The persistence of wSuz despite imperfect maternal transmission suggests positive fitness effects. Assuming a balance between selection and imperfect transmission, we expect a fitness advantage on the order of 20%. Unexpectedly, Wolbachia-infected females produce fewer progeny than do uninfected females. We do not yet understand the maintenance of wSuz in D. suzukii. The absence of detectable CI in D. suzukii and D. subpulchrella makes it unlikely that CI-based mechanisms could be used to control this species without transinfection using novel Wolbachia. Contrary to their reputation as horizontally transmitted reproductive parasites, many Wolbachia infections are acquired through introgression or cladogenesis and many cause no appreciable reproductive manipulation. Such infections, likely to be mutualistic, may be central to understanding the pervasiveness of Wolbachia among arthropods.

  14. Wolbachia-Induced Cytoplasmic Incompatibility Is Associated with Decreased Hira Expression in Male Drosophila

    PubMed Central

    Wang, Jia-Lin; Wang, Yu-Feng

    2011-01-01

    Background Wolbachia are obligate endosymbiotic bacteria that infect numerous species of arthropods and nematodes. Wolbachia can induce several reproductive phenotypes in their insect hosts including feminization, male-killing, parthenogenesis and cytoplasmic incompatibility (CI). CI is the most common phenotype and occurs when Wolbachia-infected males mate with uninfected females resulting in no or very low numbers of viable offspring. However, matings between males and females infected with the same strain of Wolbachia result in viable progeny. Despite substantial scientific effort, the molecular mechanisms underlying CI are currently unknown. Methodology/Principal Findings Gene expression studies were undertaken in Drosophila melanogaster and D. simulans which display differential levels of CI using quantitative RT-PCR. We show that Hira expression is correlated with the induction of CI and occurs in a sex-specific manner. Hira expression is significantly lower in males which induce strong CI when compared to males inducing no CI or Wolbachia-uninfected males. A reduction in Hira expression is also observed in 1-day-old males that induce stronger CI compared to 5-day-old males that induce weak or no CI. In addition, Hira mutated D. melanogaster males mated to uninfected females result in significantly decreased hatch rates comparing with uninfected crosses. Interestingly, wMel-infected females may rescue the hatch rates. An obvious CI phenotype with chromatin bridges are observed in the early embryo resulting from Hira mutant fertilization, which strongly mimics the defects associated with CI. Conclusions/Significance Our results suggest Wolbachia-induced CI in Drosophila occurs due to a reduction in Hira expression in Wolbachia-infected males leading to detrimental effects on sperm fertility resulting in embryo lethality. These results may help determine the underlying mechanism of CI and provide further insight in to the important role Hira plays in the

  15. Determination of Wolbachia Diversity in Butterflies from Western Ghats, India, by a Multigene Approach

    PubMed Central

    Salunke, Bipinchandra K.; Salunkhe, Rahul C.; Dhotre, Dhiraj P.; Walujkar, Sandeep A.; Khandagale, Avinash B.; Chaudhari, Rahul; Chandode, Rakesh K.; Ghate, Hemant V.; Patole, Milind S.; Werren, John H.

    2012-01-01

    Members of the genus Wolbachia are intracellular bacteria that are widespread in arthropods and establish diverse symbiotic associations with their hosts, ranging from mutualism to parasitism. Here we present the first detailed analyses of Wolbachia in butterflies from India with screening of 56 species. Twenty-nine species (52%) representing five families were positive for Wolbachia. This is the first report of Wolbachia infection in 27 of the 29 species; the other two were reported previously. This study also provides the first evidence of infection in the family Papilionidae. A striking diversity was observed among Wolbachia strains in butterfly hosts based on five multilocus sequence typing (MLST) genes, with 15 different sequence types (STs). Thirteen STs are new to the MLST database, whereas ST41 and ST125 were reported earlier. Some of the same host species from this study carried distinctly different Wolbachia strains, whereas the same or different butterfly hosts also harbored closely related Wolbachia strains. Butterfly-associated STs in the Indian sample originated by recombination and point mutation, further supporting the role of both processes in generating Wolbachia diversity. Recombination was detected only among the STs in this study and not in those from the MLST database. Most of the strains were remarkably similar in their wsp genotype, despite divergence in MLST. Only two wsp alleles were found among 25 individuals with complete hypervariable region (HVR) peptide profiles. Although both wsp and MLST show variability, MLST gives better separation between the strains. Completely different STs were characterized for the individuals sharing the same wsp alleles. PMID:22504801

  16. Evolutionary Dynamics of wAu-Like Wolbachia Variants in Neotropical Drosophila spp.

    PubMed Central

    Miller, Wolfgang J.; Riegler, Markus

    2006-01-01

    Wolbachia bacteria are common intracellular symbionts of arthropods and have been extensively studied in Drosophila. Most research focuses on two Old Word hosts, Drosophila melanogaster and Drosophila simulans, and does not take into account that some of the Wolbachia associations in these species may have evolved only after their fast global expansion and after the exposure to Wolbachia of previously isolated habitats. Here we looked at Wolbachia of Neotropical Drosophila species. Seventy-one lines of 16 Neotropical Drosophila species sampled in different regions and at different time points were analyzed. Wolbachia is absent in lines of Drosophila willistoni collected before the 1970s, but more recent samples are infected with a strain designated wWil. Wolbachia is absent in all other species of the willistoni group. Polymorphic wWil-related strains were detected in some saltans group species, with D. septentriosaltans being coinfected with at least four variants. Based on wsp and ftsZ sequence data, wWil of D. willistoni is identical to wAu, a strain isolated from D. simulans, but can be discriminated when using a polymorphic minisatellite marker. In contrast to wAu, which infects both germ line and somatic tissues of D. simulans, wWil is found exclusively in the primordial germ line cells of D. willistoni embryos. We report on a pool of closely related Wolbachia strains in Neotropical Drosophila species as a potential source for the wAu strain in D. simulans. Possible evolutionary scenarios reconstructing the infection history of wAu-like Wolbachia in Neotropical Drosophila species and the Old World species D. simulans are discussed. PMID:16391124

  17. Molecular diversity of Wolbachia in Lepidoptera: Prevalent allelic content and high recombination of MLST genes.

    PubMed

    Ilinsky, Yury; Kosterin, Oleg E

    2017-04-01

    Wolbachia are common endosymbiotic bacteria of Arthropoda and Nematoda that are ordinarily transmitted vertically in host lineages through the egg cytoplasm. Despite the great interest in the Wolbachia symbiont, many issues of its biology remain unclear, including its evolutionary history, routes of transfer among species, and the molecular mechanisms underlying the symbiont's effect on its host. In this report, we present data relating to Wolbachia infection in 120 species of 13 Lepidoptera families, mostly butterflies, from West Siberian localities based on Multilocus sequence typing (MLST) and the wsp locus and perform a comprehensive survey of the distribution of Wolbachia and its genetic diversity in Lepidoptera worldwide. We observed a high infection incidence in the studied region; this finding is probably also true for other temperate latitude regions because many studied species have broad Palearctic and even Holarctic distribution. Although 40 new MLST alleles and 31 new STs were described, there was no noticeable difference in the MLST allele content in butterflies and probably also in moths worldwide. A genetic analysis of Wolbachia strains revealed the MLST allele core in lepidopteran hosts worldwide, viz. the ST-41 allele content. The key finding of our study was the detection of rampant recombination among MLST haplotypes. High rates of homologous recombination between Wolbachia strains indicate a substantial contribution of genetic exchanges to the generation of new STs. This finding should be considered when discussing issues related to the reconstruction of Wolbachia evolution, divergence time, and the routes of Wolbachia transmission across arthropod hosts. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Wolbachia do not live by reproductive manipulation alone: infection polymorphism in Drosophila suzukii and D. subpulchrella

    PubMed Central

    Hamm, Christopher A.; Begun, David J.; Vo, Alexandre; Smith, Chris C. R.; Saelao, Perot; Shaver, Amanda O.; Jaenike, John; Turelli, Michael

    2014-01-01

    Drosophila suzukii recently invaded North America and Europe. Populations in Hawaii, California, New York and Nova Scotia are polymorphic for Wolbachia, typically with <20% infection frequency. The Wolbachia in D. suzukii, denoted wSuz, is closely related to wRi, the variant prevalent in continental populations of D. simulans. wSuz is also nearly identical to Wolbachia found in D. subpulchrella, plausibly D. suzukii's sister species. This suggests vertical Wolbachia transmission through cladogenesis (“cladogenic transmission”). The widespread occurrence of 7-20% infection frequencies indicates a stable polymorphism. wSuz is imperfectly maternally transmitted, with wild infected females producing on average 5-10% uninfected progeny. As expected from its low frequency, wSuz produces no cytoplasmic incompatibility (CI), i.e., no elevated embryo mortality when infected males mate with uninfected females, and no appreciable sex-ratio distortion. The persistence of wSuz despite imperfect maternal transmission suggests positive fitness effects. Assuming a balance between selection and imperfect transmission, we expect a fitness advantage on the order of 20%. Unexpectedly, Wolbachia-infected females produce fewer progeny than do uninfected females. We do not yet understand the maintenance of wSuz in D. suzukii. The absence of detectable CI in D. suzukii and D. subpulchrella makes it unlikely that CI-based mechanisms could be used to control this species without transinfection using novel Wolbachia. Contrary to their reputation as horizontally transmitted reproductive parasites, many Wolbachia infections are acquired through introgression or cladogenesis and many cause no appreciable reproductive manipulation. Such infections, likely to be mutualistic, may be central to understanding the pervasiveness of Wolbachia among arthropods. PMID:25156506

  19. Tropical tephritid fruit fly community with high incidence of shared Wolbachia strains as platform for horizontal transmission of endosymbionts.

    PubMed

    Morrow, J L; Frommer, M; Shearman, D C A; Riegler, M

    2014-12-01

    Wolbachia are endosymbiotic bacteria that infect 40-65% of arthropod species. They are primarily maternally inherited with occasional horizontal transmission for which limited direct ecological evidence exists. We detected Wolbachia in 8 out of 24 Australian tephritid species. Here, we have used multilocus sequence typing (MLST) to further characterize these Wolbachia strains, plus a novel quantitative polymerase chain reaction method for allele assignment in multiple infections. Based on five MLST loci and the Wolbachia surface protein gene (wsp), five Bactrocera and one Dacus species harboured two identical strains as double infections; furthermore, Bactrocera neohumeralis harboured both of these as single or double infections, and sibling species B. tryoni harboured one. Two Bactrocera species contained Wolbachia pseudogenes, potentially within the fruit fly genomes. A fruit fly parasitoid, Fopius arisanus shared identical alleles with two Wolbachia strains detected in one B. frauenfeldi individual. We report an unprecedented high incidence of four shared Wolbachia strains in eight host species from two trophic levels. This suggests frequent exposure to Wolbachia in this tropical tephritid community that shares host plant and parasitoid species, and also includes species that hybridize. Such insect communities may act as horizontal transmission platforms that contribute to the ubiquity of the otherwise maternally inherited Wolbachia.

  20. First record of Wolbachia in South American terrestrial isopods: Prevalence and diversity in two species of Balloniscus (Crustacea, Oniscidea)

    PubMed Central

    Almerão, Mauricio Pereira; Fagundes, Nelson Jurandi Rosa; de Araújo, Paula Beatriz; Verne, Sébastien; Grandjean, Frédéric; Bouchon, Didier; Araújo, Aldo Mellender

    2012-01-01

    Wolbachia are endosymbiotic bacteria that commonly infect arthropods, inducing certain phenotypes in their hosts. So far, no endemic South American species of terrestrial isopods have been investigated for Wolbachia infection. In this work, populations from two species of Balloniscus (B. sellowii and B. glaber) were studied through a diagnostic PCR assay. Fifteen new Wolbachia 16S rDNA sequences were detected. Wolbachia found in both species were generally specific to one population, and five populations hosted two different Wolbachia 16S rDNA sequences. Prevalence was higher in B. glaber than in B. sellowii, but uninfected populations could be found in both species. Wolbachia strains from B. sellowii had a higher genetic variation than those isolated from B. glaber. AMOVA analyses showed that most of the genetic variance was distributed among populations of each species rather than between species, and the phylogenetic analysis suggested that Wolbachia strains from Balloniscus cluster within Supergroup B, but do not form a single monophyletic clade, suggesting multiple infections for this group. Our results highlight the importance of studying Wolbachia prevalence and genetic diversity in Neotropical species and suggest that South American arthropods may harbor a great number of diverse strains, providing an interesting model to investigate the evolution of Wolbachia and its hosts. PMID:23413179

  1. Tunga penetrans: molecular identification of Wolbachia endobacteria and their recognition by antibodies against proteins of endobacteria from filarial parasites.

    PubMed

    Fischer, Peter; Schmetz, Christel; Bandi, Claudio; Bonow, Insa; Mand, Sabine; Fischer, Kerstin; Büttner, Dietrich W

    2002-01-01

    In search of Wolbachia in human parasites, Wolbachia were identified in the sand flea Tunga penetrans. PCR and DNA sequencing of the bacterial 16S rDNA, the ftsZ cell division protein, the Wolbachia surface protein (wsp) and the Wolbachia aspartate aminotransferase genes revealed a high similarity to the respective sequences of endosymbionts of filarial nematodes. Using these sequences a phylogenetic tree was generated, that indicates a close relationship between Wolbachia from T. penetrans and from filarial parasites, but possibly as a member of a new supergroup. Ultrastructural studies showed that Wolbachia are abundant in the ovaries of neosomic fleas, whereas other, smaller and morphologically distinct, bacteria were observed in the lumen of the intestine. Wolbachia were labeled by immunohistology and immunogold electron microscopy using polyclonal antibodies against wsp of Drosophila, of the filarial parasite Dirofilaria immitis, or against hsp 60 from Yersinia enterocolitica. These results show that as in filariasis, humans with tungiasis are exposed to Wolbachia. Furthermore, antisera raised against proteins of Wolbachia from arthropods or from filarial parasites can be immunologically cross-reactive.

  2. Requirement of lipid II biosynthesis for cell division in cell wall-less Wolbachia, endobacteria of arthropods and filarial nematodes.

    PubMed

    Vollmer, Jennifer; Schiefer, Andrea; Schneider, Tanja; Jülicher, Karen; Johnston, Kelly L; Taylor, Mark J; Sahl, Hans-Georg; Hoerauf, Achim; Pfarr, Kenneth

    2013-04-01

    Obligate Wolbachia endobacteria have a reduced genome and retained genes are hypothesized to be crucial for survival. Although intracellular bacteria do not need a stress-bearing peptidoglycan cell wall, Wolbachia encode proteins necessary to synthesize the peptidoglycan precursor lipid II. The activity of the enzymes catalyzing the last two steps of this pathway was previously shown, and Wolbachia are sensitive to inhibition of lipid II synthesis. A puzzling characteristic of Wolbachia is the lack of genes for l-amino acid racemases essential for lipid II synthesis. Transcription analysis showed the expression of a possible alternative racemase metC, and recombinant Wolbachia MetC indeed had racemase activity that may substitute for the absent l-Ala racemase. However, enzymes needed to form mature peptidoglycan are absent and the function of Wolbachia lipid II is unknown. Inhibition of lipid II biosynthesis resulted in enlargement of Wolbachia cells and redistribution of Wolbachia peptidoglycan-associated lipoprotein, demonstrating that lipid II is required for coordinated cell division and may interact with the lipoprotein. We conclude that lipid II is essential for Wolbachia cell division and that this function is potentially conserved in the Gram-negative bacteria. Copyright © 2013 Elsevier GmbH. All rights reserved.

  3. Job satisfaction and its influential factors.

    PubMed

    Amiri, Mohammad; Khosravi, Ahmad; Mokhtari, Abbas Ali

    2010-06-24

    This study aimed at determining the job satisfaction level of the staff in Shahroud University of Medical Sciences (SUMS), northern Iran, and its influential factors.                         In this descriptive study, conducted in 2008, the participants were 384 workers in SUMS selected through simple random sampling procedure. The par-ticipants received a 33-item questionnaire in a Likert format (8 general items and 25 items related to job satisfaction facets). The collected data in form of frequen-cies and percentages were analyzed with SPSS software. 53.4% of interviewees were female and more than 60% had associate or higher degrees. 42.6% had less than 10 yr and 30.9% had 20 to 30 yr of job experience, respectively. The mean of the overall satisfaction was 13.02 out of 20. Regarding the facets of job satisfaction, work, coworkers, supervisor, and pro-motion had the highest means, respectively. Pearson and Spearman correla-tion coefficients showed a significant relationship between overall satisfaction and the facets (P= 0.001). Analysis of variance also showed significant difference in overall satisfaction based on organizational units; however, no significant rela-tionship was observed between overall satisfaction and gender, degree, age, job experience and type of employment. Improvement of promotion process, training and qualifying manag-ers, observing meritocracy principles in appointments, using  cooperative man-agement, creating convivial and friendly atmosphere and improving work envi-ronment conditions, have brought about an increase in overall satisfaction of em-ployees in SUMS.

  4. Wolbachia small noncoding RNAs and their role in cross-kingdom communications.

    PubMed

    Mayoral, Jaime G; Hussain, Mazhar; Joubert, D Albert; Iturbe-Ormaetxe, Iñaki; O'Neill, Scott L; Asgari, Sassan

    2014-12-30

    In prokaryotes, small noncoding RNAs (snRNAs) of 50-500 nt are produced that are important in bacterial virulence and response to environmental stimuli. Here, we identified and characterized snRNAs from the endosymbiotic bacteria, Wolbachia, which are widespread in invertebrates and cause reproductive manipulations. Most importantly, some strains of Wolbachia inhibit replication of several vector-borne pathogens in insects. We demonstrate that two abundant snRNAs, WsnRNA-46 and WsnRNA-49, are expressed in Wolbachia from noncoding RNA transcripts that contain precursors with stem-loop structures. WsnRNAs were detected in Aedes aegypti mosquitoes infected with the wMelPop-CLA strain of Wolbachia and in Drosophila melanogaster and Drosophila simulans infected with wMelPop and wAu strains, respectively, indicating that the WsnRNAs are conserved across species and strains. In addition, we show that the WsnRNAs may potentially regulate host genes and Wolbachia genes. Our findings provide evidence for the production of functional snRNAs by Wolbachia that play roles in cross-kingdom communication between the endosymbiont and the host.

  5. Influence of two Wolbachia strains on population structure of East African Drosophila simulans.

    PubMed Central

    Dean, Matthew D; Ballard, Kirrie J; Glass, Anne; Ballard, J William O

    2003-01-01

    Drosophila simulans is hypothesized to have originated in continental East Africa or Madagascar. In this study, we investigated evolutionary forces operating on mitochondrial DNA (mtDNA) in populations of D. simulans from Zimbabwe, Malawi, Tanzania, and Kenya. Variation in mtDNA may be affected by positive selection, background selection, demographic history, and/or any maternally inherited factor such as the bacterial symbiont Wolbachia. In East Africa, the wRi and wMa Wolbachia strains associate with the siII or siIII mitochondrial haplogroups, respectively. To ask how polymorphism relates to Wolbachia infection status, we sequenced 1776 bp of mitochondrial DNA and 1029 bp of the X-linked per locus from 79 lines. The two southern populations were infected with wRi and exhibited significantly reduced mtDNA variation, while Wolbachia-uninfected siII flies from Tanzania and Kenya showed high levels of mtDNA polymorphism. These are the first known populations of D. simulans that do not exhibit reduced mtDNA variation. We observed no mitochondrial variation in the siIII haplogroup regardless of Wolbachia infection status, suggesting positive or background selection. These populations offer a unique opportunity to monitor evolutionary dynamics in ancestral populations that harbor multiple strains of Wolbachia. PMID:14704179

  6. Multiple Horizontal Transfers of Bacteriophage WO and Host Wolbachia in Fig Wasps in a Closed Community.

    PubMed

    Wang, Ningxin; Jia, Sisi; Xu, Heng; Liu, Yong; Huang, Dawei

    2016-01-01

    Wolbachia-bacteriophage WO is a good model system for studying interactions between bacteria and viruses. Previous surveys of insect hosts have been conducted via sampling from open or semi-open communities; however, no studies have reported the infection patterns of phage WO of insects living in a closed community. Figs and fig wasps form a peculiar closed community in which the Ficus tree provides a compact syconium habitat for a variety of fig wasp. Therefore, in this study, we performed a thorough survey of Wolbachia and bacteriophage WO infection patterns in a total of 1406 individuals from 23 fig wasps species living on three different fig tree species. The infection rates of Wolbachia and phage WO were 82.6% (19/23) and 39.1% (9/23), respectively. Additionally, phage WO from fig wasps showed strong insect host specificity based on orf7 sequences from fig wasps and 21 other insect species. Probably due to the physical barrier of fig syconium, most phage WO from fig wasps form a specific clade. Phylogenetic analysis showed the absence of congruence between WO and host Wolbachia, WO and insect host, as well as Wolbachia and fig wasps, suggesting that both Wolbachia and phage WO exchanged frequently and independently within the closed syconium. Thus, the infection pattern of bacteriophage WO from fig wasps appeared quite different from that in other insects living outside, although the effect and the transfer routes of phage WO are unclear, which need to be investigated in the future.

  7. Multiple Horizontal Transfers of Bacteriophage WO and Host Wolbachia in Fig Wasps in a Closed Community

    PubMed Central

    Wang, Ningxin; Jia, Sisi; Xu, Heng; Liu, Yong; Huang, Dawei

    2016-01-01

    Wolbachia-bacteriophage WO is a good model system for studying interactions between bacteria and viruses. Previous surveys of insect hosts have been conducted via sampling from open or semi-open communities; however, no studies have reported the infection patterns of phage WO of insects living in a closed community. Figs and fig wasps form a peculiar closed community in which the Ficus tree provides a compact syconium habitat for a variety of fig wasp. Therefore, in this study, we performed a thorough survey of Wolbachia and bacteriophage WO infection patterns in a total of 1406 individuals from 23 fig wasps species living on three different fig tree species. The infection rates of Wolbachia and phage WO were 82.6% (19/23) and 39.1% (9/23), respectively. Additionally, phage WO from fig wasps showed strong insect host specificity based on orf7 sequences from fig wasps and 21 other insect species. Probably due to the physical barrier of fig syconium, most phage WO from fig wasps form a specific clade. Phylogenetic analysis showed the absence of congruence between WO and host Wolbachia, WO and insect host, as well as Wolbachia and fig wasps, suggesting that both Wolbachia and phage WO exchanged frequently and independently within the closed syconium. Thus, the infection pattern of bacteriophage WO from fig wasps appeared quite different from that in other insects living outside, although the effect and the transfer routes of phage WO are unclear, which need to be investigated in the future. PMID:26913026

  8. Transcriptional Regulation of Culex pipiens Mosquitoes by Wolbachia Influences Cytoplasmic Incompatibility

    PubMed Central

    Harris, Simon; Kambris, Zakaria; Sutton, Elizabeth R.; Bonsall, Michael B.; Parkhill, Julian; Sinkins, Steven P.

    2013-01-01

    Cytoplasmic incompatibility (CI) induced by the endosymbiont Wolbachia pipientis causes complex patterns of crossing sterility between populations of the Culex pipiens group of mosquitoes. The molecular basis of the phenotype is yet to be defined. In order to investigate what host changes may underlie CI at the molecular level, we examined the transcription of a homolog of the Drosophila melanogaster gene grauzone that encodes a zinc finger protein and acts as a regulator of female meiosis, in which mutations can cause sterility. Upregulation was observed in Wolbachia-infected C. pipiens group individuals relative to Wolbachia-cured lines and the level of upregulation differed between lines that were reproductively incompatible. Knockdown analysis of this gene using RNAi showed an effect on hatch rates in a Wolbachia infected Culex molestus line. Furthermore, in later stages of development an effect on developmental progression in CI embryos occurs in bidirectionally incompatible crosses. The genome of a wPip Wolbachia strain variant from Culex molestus was sequenced and compared with the genome of a wPip variant with which it was incompatible. Three genes in inserted or deleted regions were newly identified in the C. molestus wPip genome, one of which is a transcriptional regulator labelled wtrM. When this gene was transfected into adult Culex mosquitoes, upregulation of the grauzone homolog was observed. These data suggest that Wolbachia-mediated regulation of host gene expression is a component of the mechanism of cytoplasmic incompatibility. PMID:24204251

  9. Multiple Wolbachia determinants control the evolution of cytoplasmic incompatibilities in Culex pipiens mosquito populations.

    PubMed

    Atyame, Celestine M; Duron, Olivier; Tortosa, Pablo; Pasteur, Nicole; Fort, Philippe; Weill, Mylene

    2011-01-01

    Wolbachia are maternally inherited endosymbionts that can invade arthropod populations through manipulation of their reproduction. In mosquitoes, Wolbachia induce embryonic death, known as cytoplasmic incompatibility (CI), whenever infected males mate with females either uninfected or infected with an incompatible strain. Although genetic determinants of CI are unknown, a functional model involving the so-called mod and resc factors has been proposed. Natural populations of Culex pipiens mosquito display a complex CI relationship pattern associated with the highest Wolbachia (wPip) genetic polymorphism reported so far. We show here that C. pipiens populations from La Réunion, a geographically isolated island in the southwest of the Indian Ocean, are infected with genetically closely related wPip strains. Crossing experiments reveal that these Wolbachia are all mutually compatible. However, crosses with genetically more distant wPip strains indicate that Wolbachia strains from La Réunion belong to at least five distinct incompatibility groups (or crossing types). These incompatibility properties which are strictly independent from the nuclear background, formally establish that in C. pipiens, CI is controlled by several Wolbachia mod/resc factors.

  10. Dynamics of Wolbachia pipientis Gene Expression Across the Drosophila melanogaster Life Cycle

    PubMed Central

    Gutzwiller, Florence; Carmo, Catarina R.; Miller, Danny E.; Rice, Danny W.; Newton, Irene L. G.; Hawley, R. Scott; Teixeira, Luis; Bergman, Casey M.

    2015-01-01

    Symbiotic interactions between microbes and their multicellular hosts have manifold biological consequences. To better understand how bacteria maintain symbiotic associations with animal hosts, we analyzed genome-wide gene expression for the endosymbiotic α-proteobacteria Wolbachia pipientis across the entire life cycle of Drosophila melanogaster. We found that the majority of Wolbachia genes are expressed stably across the D. melanogaster life cycle, but that 7.8% of Wolbachia genes exhibit robust stage- or sex-specific expression differences when studied in the whole-organism context. Differentially-expressed Wolbachia genes are typically up-regulated after Drosophila embryogenesis and include many bacterial membrane, secretion system, and ankyrin repeat-containing proteins. Sex-biased genes are often organized as small operons of uncharacterized genes and are mainly up-regulated in adult Drosophila males in an age-dependent manner. We also systematically investigated expression levels of previously-reported candidate genes thought to be involved in host-microbe interaction, including those in the WO-A and WO-B prophages and in the Octomom region, which has been implicated in regulating bacterial titer and pathogenicity. Our work provides comprehensive insight into the developmental dynamics of gene expression for a widespread endosymbiont in its natural host context, and shows that public gene expression data harbor rich resources to probe the functional basis of the Wolbachia-Drosophila symbiosis and annotate the transcriptional outputs of the Wolbachia genome. PMID:26497146

  11. Vector competence of Malaysian Aedes albopictus with and without Wolbachia to four dengue virus serotypes.

    PubMed

    Joanne, Sylvia; Vythilingam, Indra; Teoh, Boon-Teong; Leong, Cherng-Shii; Tan, Kim-Kee; Wong, Meng-Li; Yugavathy, Nava; AbuBakar, Sazaly

    2017-09-01

    To determine the susceptibility status of Aedes albopictus with and without Wolbachia to the four dengue virus serotypes. Two newly colonised colonies of Ae. albopictus from the wild were used for the study. One colony was naturally infected with Wolbachia while in the other Wolbachia was removed by tetracycline treatment. Both colonies were orally infected with dengue virus-infected fresh blood meal. Dengue virus load was measured using quantitative RT-PCR at four-time intervals in the salivary glands, midguts and ovaries. Wolbachia did not significantly affect Malaysian Ae. albopictus dengue infection or the dissemination rate for all four dengue virus serotypes. Malaysian Ae. albopictus had the highest replication kinetics for DENV-1 and the highest salivary gland and midgut infection rate for DENV-4. Wolbachia, which naturally exists in Malaysian Ae. albopictus, does not significantly affect dengue virus replication. Malaysian Ae. albopictus is susceptible to dengue virus infections and capable of transmitting dengue virus, especially DENV-1 and DENV-4. Removal of Wolbachia from Malaysian Ae. albopictus would not reduce their susceptibility status. © 2017 John Wiley & Sons Ltd.

  12. Tetracycline treatment targeting Wolbachia affects expression of an array of proteins in Brugia malayi parasite.

    PubMed

    Dangi, Anil; Vedi, Satish; Nag, Jeetendra Kumar; Paithankar, Sameer; Singh, Mahendra Pratap; Kar, Santosh Kumar; Dube, Anuradha; Misra-Bhattacharya, Shailja

    2009-09-01

    Wolbachia is an intracellular endosymbiont of Brugia malayi parasite whose presence is essential for the survival of the parasite. Treatment of B. malayi-infected jirds with tetracycline eliminates Wolbachia, which affects parasite survival and fitness. In the present study we have tried to identify parasite proteins that are affected when Wolbachia is targeted by tetracycline. For this Wolbachia depleted parasites (B. malayi) were obtained by tetracycline treatment of infected Mongolian jirds (Meriones unguiculatus) and their protein profile after 2-DE separation was compared with that of untreated parasites harboring Wolbachia. Approximately 100 protein spots could be visualized followed by CBB staining of 2-D gel and included for comparative analysis. Of these, 54 showed differential expressions, while two new protein spots emerged (of 90.3 and 64.4 kDa). These proteins were subjected to further analysis by MALDI-TOF for their identification using Brugia coding sequence database composed of both genomic and EST sequences. Our study unravels two crucial findings: (i) the parasite or Wolbachia proteins, which disappeared/down-regulated appear be essential for parasite survival and may be used as drug targets and (ii) tetracycline treatment interferes with the regulatory machinery vital for parasites cellular integrity and defense and thus could possibly be a molecular mechanism for the killing of filarial parasite. This is the first proteomic study substantiating the wolbachial genome integrity with its nematode host and providing functional genomic data of human lymphatic filarial parasite B. malayi.

  13. Identification and characterization of Wolbachia in Solenopsis saevissima fire ants (Hymenoptera: Formicidae) in southeastern Brazil.

    PubMed

    Fernando de Souza, Rodrigo; Daivison Silva Ramalho, João; Santina de Castro Morini, Maria; Wolff, José Luiz Caldas; Araújo, Ronaldo Carvalho; Mascara, Douglas

    2009-03-01

    The genus Solenopsis appears to have evolved and radiated very rapidly in South America and then spread throughout the rest of the continent. As part of the expansion process, distribution patterns and different degrees of geographic isolation among populations of S. saevissima can be observed. We have investigated the presence of Wolbachia in 52 colonies and 1623 individuals in southeastern Brazil. Detection of Wolbachia infection was based on amplification of the 16S rRNA and wsp genes by polymerase chain reactions. Wolbachia was found in only one of the four locations investigated and it was observed that the populations were polymorphic for infection. The infection level observed increased during the period of screening. In particular, double infection (16SWA and B) increased from 44% in 2005 to 90% in 2006. The A-group of Wolbachia from the wsp sequences was determined by sequencing. However, two variant wsp sequences were detected in Wolbachia present in these populations. The alignment of our sequences with those deposited in GenBank indicated significant differences in relation to homologous sequences. Phylogenetic relationships were inferred using parsimony, and confidence intervals were estimated by bootstrapping. Then the divergence of the Wolbachia of S. saevissima in the populations studied with other variants allowed us to verify that wSS1 and dwSS2 formed a distinct clade within the A-group (>75%). These results can be useful in studies on the dynamics of ant populations.

  14. Detection of the Wolbachia Protein WPIP0282 in Mosquito Spermathecae: Implications for Cytoplasmic Incompatibility

    PubMed Central

    Beckmann, John F.; Fallon, Ann M.

    2013-01-01

    Cytoplasmic incompatibility (CI) is a conditional sterility induced by the bacterium Wolbachia pipientis that infects reproductive tissues in many arthropods. Although CI provides a potential tool to control insect vectors of arthropod-borne diseases, the molecular basis for CI induction is unknown. We hypothesized that a Wolbachia-encoded, CI-inducing factor would be enriched in sperm recovered from spermathecae of female mosquitoes. Using SDS-PAGE and mass spectrometry, we detected peptides from the 56 kDa hypothetical protein, encoded by wPip_0282, associated with sperm transferred to females by Wolbachia infected males. We also detected peptides from the same protein in Wolbachia infected ovaries. Homologs of wPip_0282 and the co-transcribed downstream gene, wPip_0283, occur as multiple divergent copies in genomes of CI-inducing strains of Wolbachia. The operon is located in a genomic context that includes mobile genetic elements. The absence of wPip_0282 and wPip_0283 homologs from genomes of Wolbachia in filarial nematodes, as well as other members of the Rickettsiales, suggests a role as a candidate CI effector. PMID:23856508

  15. Genomic evidence for plant-parasitic nematodes as the earliest Wolbachia hosts

    PubMed Central

    Brown, Amanda M. V.; Wasala, Sulochana K.; Howe, Dana K.; Peetz, Amy B.; Zasada, Inga A.; Denver, Dee R.

    2016-01-01

    Wolbachia, one of the most widespread endosymbionts, is a target for biological control of mosquito-borne diseases (malaria and dengue virus), and antibiotic elimination of infectious filarial nematodes. We sequenced and analyzed the genome of a new Wolbachia strain (wPpe) in the plant-parasitic nematode Pratylenchus penetrans. Phylogenomic analyses placed wPpe as the earliest diverging Wolbachia, suggesting two evolutionary invasions into nematodes. The next branches comprised strains in sap-feeding insects, suggesting Wolbachia may have first evolved as a nutritional mutualist. Genome size, protein content, %GC, and repetitive DNA allied wPpe with mutualistic Wolbachia, whereas gene repertoire analyses placed it between parasite (A, B) and mutualist (C, D, F) groups. Conservation of iron metabolism genes across Wolbachia suggests iron homeostasis as a potential factor in its success. This study enhances our understanding of this globally pandemic endosymbiont, highlighting genetic patterns associated with host changes. Combined with future work on this strain, these genomic data could help provide potential new targets for plant-parasitic nematode control. PMID:27734894

  16. Life-shortening Wolbachia infection reduces population growth of Aedes aegypti.

    PubMed

    Suh, Eunho; Mercer, David R; Dobson, Stephen L

    2017-08-01

    Wolbachia bacteria are being introduced into natural populations of vector mosquitoes, with the goal of reducing the transmission of human diseases such as Zika and dengue fever. The successful establishment of Wolbachia infection is largely dependent on the effects of Wolbachia infection to host fitness, but the effects of Wolbachia infection on the individual life-history traits of immature mosquitoes can vary. Here, the effects of life-shortening Wolbachia (wMelPop) on population growth of infected individuals were evaluated by measuring larval survival, developmental time and adult size of Aedes aegypti in intra- (infected or uninfected only) and inter-group (mixed with infected and uninfected) larval competition assays. At low larval density conditions, the population growth of wMelPop infected and uninfected individuals was similar. At high larval densities, wMelPop infected individuals had a significantly reduced population growth rate relative to uninfected individuals, regardless of competition type. We discuss the results in relation to the invasion of the wMelPop Wolbachia infection into naturally uninfected populations. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Evidence for selective sweeps by Wolbachia infections: phylogeny of Altica leaf beetles and their reproductive parasites.

    PubMed

    Jäckel, Regina; Mora, Diana; Dobler, Susanne

    2013-08-01

    Infections with maternally inherited Wolbachia bacteria may have dramatic influences on reproductive traits and speciation patterns of their hosts. We here show that in the beetle genus Altica, infection has influenced phylogenetic patterns of the host's mtDNA and different strains led to repeated selective sweeps. By comparing a COI/II-based phylogeny of the hosts with a phylogeny of the bacteria based on ftsZ, we show that cospeciation is rare and restricted to few recently diverged species. While in general each species apparently harbours a single Wolbachia strain, Altica lythri presents a strikingly different pattern: in the polyphyletic species, three highly divergent mtDNA haplotypes (2.1-4.6% p-distance) are coupled with three different Wolbachia strains (wLytA1, wLytA2 and wLytB). These haplotypes and Wolbachia strains are widely distributed and mostly found in sympatry. A phylogeny based on microsatellite data supports the monophyly of A. lythri. The discrepancy between mtDNA and nuclear phylogeny may best be explained by interspecific hybridization that led to introgression of mtDNA coupled with a different Wolbachia strain. Selective sweeps apparently drove the introgressed haplotypes to widespread distribution. As for effects of Wolbachia on reproduction, infection with wLytA1 appears to be correlated with a substantial sex ratio distortion, which was most prominent in A. lythri.

  18. The intracellular bacterium Wolbachia uses parasitoid wasps as phoretic vectors for efficient horizontal transmission.

    PubMed

    Ahmed, Muhammad Z; Li, Shao-Jian; Xue, Xia; Yin, Xiang-Jie; Ren, Shun-Xiang; Jiggins, Francis M; Greeff, Jaco M; Qiu, Bao-Li

    2015-02-01

    Facultative bacterial endosymbionts are associated with many arthropods and are primarily transmitted vertically from mother to offspring. However, phylogenetic affiliations suggest that horizontal transmission must also occur. Such horizontal transfer can have important biological and agricultural consequences when endosymbionts increase host fitness. So far horizontal transmission is considered rare and has been difficult to document. Here, we use fluorescence in situ hybridization (FISH) and multi locus sequence typing (MLST) to reveal a potentially common pathway of horizontal transmission of endosymbionts via parasitoids of insects. We illustrate that the mouthparts and ovipositors of an aphelinid parasitoid become contaminated with Wolbachia when this wasp feeds on or probes Wolbachia-infected Bemisia tabaci AsiaII7, and non-lethal probing of uninfected B. tabaci AsiaII7 nymphs by parasitoids carrying Wolbachia resulted in newly and stably infected B. tabaci matrilines. After they were exposed to infected whitefly, the parasitoids were able to transmit Wolbachia efficiently for the following 48 h. Whitefly infected with Wolbachia by parasitoids had increased survival and reduced development times. Overall, our study provides evidence for the horizontal transmission of Wolbachia between insect hosts by parasitic wasps, and the enhanced survival and reproductive abilities of insect hosts may adversely affect biological control programs.

  19. Wolbachia density and virulence attenuation after transfer into a novel host.

    PubMed

    McGraw, E A; Merritt, D J; Droller, J N; O'Neill, S L

    2002-03-05

    The factors that control replication rate of the intracellular bacterium Wolbachia pipientis in its insect hosts are unknown and difficult to explore, given the complex interaction of symbiont and host genotypes. Using a strain of Wolbachia that is known to over-replicate and shorten the lifespan of its Drosophila melanogaster host, we have tracked the evolution of replication control in both somatic and reproductive tissues in a novel host/Wolbachia association. After transinfection (the transfer of a Wolbachia strain into a different species) of the over-replicating Wolbachia popcorn strain from D. melanogaster to Drosophila simulans, we demonstrated that initial high densities in the ovaries were in excess of what was required for perfect maternal transmission, and were likely causing reductions in reproductive fitness. Both densities and fitness costs associated with ovary infection rapidly declined in the generations after transinfection. The early death effect in D. simulans attenuated only slightly and was comparable to that induced in D. melanogaster. This study reveals a strong host involvement in Wolbachia replication rates, the independence of density control responses in different tissues, and the strength of natural selection acting on reproductive fitness.

  20. Loss of Wolbachia infection during colonisation in the invasive Argentine ant Linepithema humile.

    PubMed

    Reuter, M; Pedersen, J S; Keller, L

    2005-03-01

    WOLBACHIA are maternally inherited bacteria, which are very common in arthropods and nematodes. Wolbachia infection may affect host reproduction through feminisation, parthenogenesis, male-killing, cytoplasmic incompatibility and increased fecundity. Previous studies showing discrepancies between the phylogenies of Wolbachia and its arthropod hosts indicate that infection is frequently lost, but the causes of symbiont extinction have so far remained elusive. Here, we report data showing that colonisation of new habitats is a possible mechanism leading to the loss of infection. The presence and prevalence of Wolbachia were studied in three native and eight introduced populations of the Argentine ant Linepithema humile. The screening shows that the symbiont is common in the three native L. humile populations analysed. In contrast, Wolbachia was detected in only one of the introduced populations. The loss of infection associated with colonisation of new habitats may result from drift (founder effect) or altered selection pressures in the new habitat. Furthermore, a molecular phylogeny based on sequences of the Wolbachia wsp gene indicates that L. humile has been infected by a single strain. Horizontal transmission of the symbiont may be important in ants as suggested by the sequence similarity of strains in the three genera Linepithema, Acromyrmex, and Solenopsis native from South and Central America.

  1. Proteomic profiling of a robust Wolbachia infection in an Aedes albopictus mosquito cell line

    PubMed Central

    Baldridge, Gerald D; Baldridge, Abigail S; Witthuhn, Bruce A; Higgins, LeeAnn; Markowski, Todd W; Fallon, Ann M

    2014-01-01

    Wolbachia pipientis a widespread vertically transmitted intracellular bacterium, provides a tool for insect control through manipulation of host-microbe interactions. We report proteomic characterization of wStr, a Wolbachia strain associated with a strong cytoplasmic incompatibility phenotype in its native host, Laodelphax striatellus. In the Aedes albopictus C/wStr1 mosquito cell line, wStr maintains a robust, persistent infection. MS/MS analyses of gel bands revealed a protein “footprint” dominated by Wolbachia-encoded chaperones, stress response and cell membrane proteins, including the surface antigen WspA, a peptidoglycan-associated lipoprotein and a 73 kDa outer membrane protein. Functional classifications and estimated abundance levels of 790 identified proteins suggested that expression, stabilization and secretion of proteins predominate over bacterial genome replication and cell division. High relative abundances of cysteine desulfurase, serine/glycine hydroxymethyl transferase, and components of the α-ketoglutarate dehydrogenase complex in conjunction with above average abundances of glutamate dehydrogenase and proline utilization protein A support Wolbachia genome-based predictions for amino acid metabolism as a primary energy source. wStr expresses 15 Vir proteins of a Type IV secretion system and its transcriptional regulator. Proteomic characterization of a robust insect-associated Wolbachia strain provides baseline information that will inform further development of in vitro protocols for Wolbachia manipulation. PMID:25155417

  2. An endosymbiotic bacterium in a plant-parasitic nematode: member of a new Wolbachia supergroup.

    PubMed

    Haegeman, Annelies; Vanholme, Bartel; Jacob, Joachim; Vandekerckhove, Tom T M; Claeys, Myriam; Borgonie, Gaetan; Gheysen, Godelieve

    2009-07-15

    Wolbachia is an endosymbiotic bacterium widely present in arthropods and animal-parasitic nematodes. Despite previous efforts, it has never been identified in plant-parasitic nematodes. Random sequencing of genes expressed by the burrowing nematode Radopholus similis resulted in several sequences with similarity to Wolbachia genes. The presence of a Wolbachia-like endosymbiont in this plant-parasitic nematode was investigated using both morphological and molecular approaches. Transmission electronmicroscopy, fluorescent immunolocalisation and staining with DAPI confirmed the presence of the endosymbiont within the reproductive tract of female adults. 16S rDNA, ftsZ and groEL gene sequences showed that the endosymbiont of R. similis is distantly related to the known Wolbachia supergroups. Finally, based on our initial success in finding sequences of this endosymbiont by screening an expressed sequence tag (EST) dataset, all nematode ESTs were mined for Wolbachia-like sequences. Although the retained sequences belonged to six different nematode species, R. similis was the only plant-parasitic nematode with traces of Wolbachia. Based on our phylogenetic study and the current literature we designate the endosymbiont of R. similis to a new supergroup (supergroup I) rather than considering it as a new species. Although its role remains unknown, the endosymbiont was found in all individuals tested, pointing towards an essential function of the bacteria.

  3. Broader prevalence of Wolbachia in insects including potential human disease vectors.

    PubMed

    de Oliveira, C D; Gonçalves, D S; Baton, L A; Shimabukuro, P H F; Carvalho, F D; Moreira, L A

    2015-06-01

    Wolbachia are intracellular, maternally transmitted bacteria considered the most abundant endosymbionts found in arthropods. They reproductively manipulate their host in order to increase their chances of being transmitted to the offspring, and currently are being used as a tool to control vector-borne diseases. Studies on distribution of Wolbachia among its arthropod hosts are important both for better understanding why this bacterium is so common, as well as for its potential use as a biological control agent. Here, we studied the incidence of Wolbachia in a broad range of insect species, collected from different regions of Brazil, using three genetic markers (16S rRNA, wsp and ftsZ), which varied in terms of their sensitivity to detect this bacterium. The overall incidence of Wolbachia among species belonging to 58 families and 14 orders was 61.9%. The most common positive insect orders were Coleoptera, Diptera, Hemiptera and Hymenoptera, with Diptera and Hemiptera having the highest numbers of Wolbachia-positive families. They included potential human disease vectors whose infection status has never been reported before. Our study further shows the importance of using quantitative polymerase chain reaction for high-throughput and sensitive Wolbachia screening.

  4. The Intracellular Bacterium Wolbachia Uses Parasitoid Wasps as Phoretic Vectors for Efficient Horizontal Transmission

    PubMed Central

    Ahmed, Muhammad Z.; Li, Shao-Jian; Xue, Xia; Yin, Xiang-Jie; Ren, Shun-Xiang; Jiggins, Francis M.; Greeff, Jaco M.; Qiu, Bao-Li

    2015-01-01

    Facultative bacterial endosymbionts are associated with many arthropods and are primarily transmitted vertically from mother to offspring. However, phylogenetic affiliations suggest that horizontal transmission must also occur. Such horizontal transfer can have important biological and agricultural consequences when endosymbionts increase host fitness. So far horizontal transmission is considered rare and has been difficult to document. Here, we use fluorescence in situ hybridization (FISH) and multi locus sequence typing (MLST) to reveal a potentially common pathway of horizontal transmission of endosymbionts via parasitoids of insects. We illustrate that the mouthparts and ovipositors of an aphelinid parasitoid become contaminated with Wolbachia when this wasp feeds on or probes Wolbachia-infected Bemisia tabaci AsiaII7, and non-lethal probing of uninfected B. tabaci AsiaII7 nymphs by parasitoids carrying Wolbachia resulted in newly and stably infected B. tabaci matrilines. After they were exposed to infected whitefly, the parasitoids were able to transmit Wolbachia efficiently for the following 48 h. Whitefly infected with Wolbachia by parasitoids had increased survival and reduced development times. Overall, our study provides evidence for the horizontal transmission of Wolbachia between insect hosts by parasitic wasps, and the enhanced survival and reproductive abilities of insect hosts may adversely affect biological control programs. PMID:25675099

  5. Dynamics of Wolbachia pipientis Gene Expression Across the Drosophila melanogaster Life Cycle.

    PubMed

    Gutzwiller, Florence; Carmo, Catarina R; Miller, Danny E; Rice, Danny W; Newton, Irene L G; Hawley, R Scott; Teixeira, Luis; Bergman, Casey M

    2015-10-23

    Symbiotic interactions between microbes and their multicellular hosts have manifold biological consequences. To better understand how bacteria maintain symbiotic associations with animal hosts, we analyzed genome-wide gene expression for the endosymbiotic α-proteobacteria Wolbachia pipientis across the entire life cycle of Drosophila melanogaster. We found that the majority of Wolbachia genes are expressed stably across the D. melanogaster life cycle, but that 7.8% of Wolbachia genes exhibit robust stage- or sex-specific expression differences when studied in the whole-organism context. Differentially-expressed Wolbachia genes are typically up-regulated after Drosophila embryogenesis and include many bacterial membrane, secretion system, and ankyrin repeat-containing proteins. Sex-biased genes are often organized as small operons of uncharacterized genes and are mainly up-regulated in adult Drosophila males in an age-dependent manner. We also systematically investigated expression levels of previously-reported candidate genes thought to be involved in host-microbe interaction, including those in the WO-A and WO-B prophages and in the Octomom region, which has been implicated in regulating bacterial titer and pathogenicity. Our work provides comprehensive insight into the developmental dynamics of gene expression for a widespread endosymbiont in its natural host context, and shows that public gene expression data harbor rich resources to probe the functional basis of the Wolbachia-Drosophila symbiosis and annotate the transcriptional outputs of the Wolbachia genome. Copyright © 2015 Gutzwiller et al.

  6. Defining Brugia malayi and Wolbachia symbiosis by stage-specific dual RNA-seq.

    PubMed

    Grote, Alexandra; Voronin, Denis; Ding, Tao; Twaddle, Alan; Unnasch, Thomas R; Lustigman, Sara; Ghedin, Elodie

    2017-03-01

    Filarial nematodes currently infect up to 54 million people worldwide, with millions more at risk for infection, representing the leading cause of disability in the developing world. Brugia malayi is one of the causative agents of lymphatic filariasis and remains the only human filarial parasite that can be maintained in small laboratory animals. Many filarial nematode species, including B. malayi, carry an obligate endosymbiont, the alpha-proteobacteria Wolbachia, which can be eliminated through antibiotic treatment. Elimination of the endosymbiont interferes with development, reproduction, and survival of the worms within the mamalian host, a clear indicator that the Wolbachia are crucial for survival of the parasite. Little is understood about the mechanism underlying this symbiosis. To better understand the molecular interplay between these two organisms we profiled the transcriptomes of B. malayi and Wolbachia by dual RNA-seq across the life cycle of the parasite. This helped identify functional pathways involved in this essential symbiotic relationship provided by the co-expression of nematode and bacterial genes. We have identified significant stage-specific and gender-specific differential expression in Wolbachia during the nematode's development. For example, during female worm development we find that Wolbachia upregulate genes involved in ATP production and purine biosynthesis, as well as genes involved in the oxidative stress response. This global transcriptional analysis has highlighted specific pathways to which both Wolbachia and B. malayi contribute concurrently over the life cycle of the parasite, paving the way for the development of novel intervention strategies.

  7. Wolbachia from Drosophila incompta: just a hitchhiker shared by Drosophila in the New and Old World?

    PubMed

    Wallau, G L; da Rosa, M T; De Ré, F C; Loreto, E L S

    2016-08-01

    Wolbachia are intracellular endosymbionts that infect arthropods and filarial nematodes, occasionally causing a wide variety of modifications in host biology, such as male-killing and cytoplasmic incompatibility (CI), amongst others. This study assembled draft genomes for Wolbachia infecting Drosophila incompta, a species that uses flowers as exclusive breeding and feeding sites, in two distinct Brazilian populations. The absence of four genes involved in CI from this genome, together with literature reports of low frequencies of infected flies in wild populations that contain high mitogenome polymorphism, suggests that this bacterium does not induce CI in D. incompta. Phylogenomic analysis placed Wolbachia infecting D. incompta as closely related to the wMel strain which received such name since it was originally detected in Drosophila melanogaster. In addition, phylogenetic analysis using the Wolbachia surface protein gene and five genes used for multilocus sequence typing of Wolbachia found infecting Drosophila and other arthropod species of Old and New World displayed a complex evolutionary scenario involving recent horizontal transfer bursts in all major clades of Wolbachia pipens belonging to the supergroup A in both geographical regions. © 2016 The Royal Entomological Society.

  8. Molecular evidence of Wolbachia endosymbiosis in Mansonella perstans in Gabon, Central Africa.

    PubMed

    Gehringer, Christian; Kreidenweiss, Andrea; Flamen, Arnaud; Antony, Justin S; Grobusch, Martin P; Bélard, Sabine

    2014-11-15

    The discovery of obligatory intracellular bacteria of the genus Wolbachia in filariae infecting humans led to the use of antibiotics as a potent treatment option. Mansonella perstans is the cause of the second most prevalent filariasis in Gabon, but so far reports on the presence of Wolbachia in this nematode have been inconsistent. We report on the presence of Wolbachia in M. perstans in patients from Gabon, which we identified using polymerase chain reaction (PCR) with primer sets specific for 16S rDNA and ftsZ. Sequence analysis revealed a single consensus sequence, which could be phylogenetically assigned to Wolbachia of the supergroup F. Wolbachia could only be identified in 5 of 14 or 7 of 14 cases, depending on the investigated gene; detection of Wolbachia was associated with higher-level filaremia. Before generalizing the use of antibiotics for mansonellosis, further clarification of the obligatory nature of the endosymbiosis in this nematode is needed. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. Evolution of cooperation in a heterogeneous population with influential individuals

    NASA Astrophysics Data System (ADS)

    Zhuang, Qian; Wang, Dong; Fan, Ying; Di, Zengru

    2012-02-01

    Influential individuals are introduced and integrated with the public goods game (PGG) to investigate their influence on the emergence and evolution of cooperation. In the model, some influential individuals whose behaviors can be controlled by us are introduced into a homogeneous population on a square lattice. The influential individuals can play three kinds of roles: I. exemplar, II. supervisor with the power to punish defectors, and III. supervisor with the power to reward cooperative co-players. It is found that the existence of influential individuals who play Role I turns out to be detrimental to cooperation and that the larger the number of influential individuals is, the more difficult it is for cooperation to be maintained. For those playing supervisory roles, both punishment and reward are found to be effective ways for the influential individuals to promote and stabilize cooperative behavior. By comparing the critical costs and the mean payoffs for a low multiplication factor under the role of punishment and the role of reward, it is found that reward is a more effective intervention measure than punishment for influential individuals seeking to improve cooperation and that reward leads to a higher mean payoff.

  10. Passenger behavior in trains during emergency situations.

    PubMed

    Dell'Olio, Luigi; Ibeas, Angel; Barreda, Rosa; Sañudo, Roberto

    2013-09-01

    This research presents a methodology for analyzing the behavior of people (passengers and crew) involved in emergency situations on passenger trains. This methodological tool centers around a qualitative character study coming from Focus Groups (FG) and in-depth interviews to extract the determinant variables on passenger and crew behavior when faced with certain emergency situations on trains. This research has led to the creation of a classification of possible behaviors associated to each type of incident and dependent on certain variables. The qualitative study was used as the basis for modeling stated preference data using logit type discrete choice models to characterize and quantify the behavior. The most important results show that the determinant variables on passenger behavior correspond to the type of emergency suffered (its degree of seriousness), the type of passenger, the reasons for the journey (demands of time), the information received during the incident, the relationship between crew and passengers, the duration of the incident and the conditions (temperature control, availability of water, occupancy of the train), the distance to the destination station, and finally, the outside weather conditions. This research was carried out using the Spanish railway network as its reference, although it is applicable to any geographical area. The results show that the information variable should be considered in the development of future research and that the evidences of this research can be used to develop behavioral models for modeling railway passenger evacuations. Copyright © 2013 National Safety Council and Elsevier Ltd. All rights reserved.

  11. Access improvement to aircraft passengers' hand luggage.

    PubMed

    Alberda, W; Kampinga, O; Kassels, R; van Kester, R; Noriega, J; Vink, P

    2015-01-01

    Efficient use of space and passenger comfort in aircraft interiors are major issues. There is not much research available about the flying experience regarding passengers' personal belongings. The objective of this study is to explore concepts within the current aircraft seats which improve the passenger experience related to their personal belongings like wallets, mobile phones and laptops. Through on-site observations, interviews and online questionnaires, data regarding the number of personal belongings taken into the airplane and opinions about access to hand luggage were gathered. These data were used to develop different concepts to optimize the aircraft interior, which were evaluated by passengers. Almost every passenger carries a phone (88%), wallet (94%), travel documents (98%) and keys (76%) with them and they like to have these stored close by. Passengers rate the concept that provides integrated storage in the tray table of the aircraft seat the best. Extra storage possibility in the table-tray seems a promising solution according to the passengers.

  12. Comparison of airline passenger oxygen systems.

    PubMed

    Byrne, N J

    1995-08-01

    The principal sources of oxygen for inflight passenger use, scheduled and unscheduled, are examined. Present practices of assessment of the passenger's "fitness to fly" are described. Three partner airlines, British Airways, U.S. Air, and Qantas, catering for more than 8000 oxygen requests annually, are compared. Analysis of customer use suggests that medical oxygen requests are frequently not clinically justified. The growth in demand, for both scheduled and unscheduled use of an expensive resource, supports the need for a "recommended best practice" among carriers. Passengers with respiratory disorders who will most benefit from inflight oxygen are vulnerable either to hypoxia or asthma.

  13. 19 CFR 122.88 - Aircraft carrying domestic (stopover) passengers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Aircraft carrying domestic (stopover) passengers... Passengers § 122.88 Aircraft carrying domestic (stopover) passengers. Airlines that commingle domestic... domestic (stopover) passengers must be transported on U.S.-registered aircraft, or...

  14. 49 CFR 523.5 - Non-passenger automobile.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 6 2014-10-01 2014-10-01 false Non-passenger automobile. 523.5 Section 523.5... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.5 Non-passenger automobile. A non-passenger automobile means an automobile that is not a passenger automobile or a work truck and...

  15. 49 CFR 523.5 - Non-passenger automobile.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 6 2012-10-01 2012-10-01 false Non-passenger automobile. 523.5 Section 523.5... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.5 Non-passenger automobile. A non-passenger automobile means an automobile that is not a passenger automobile or a work truck and...

  16. 49 CFR 523.5 - Non-passenger automobile.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 6 2011-10-01 2011-10-01 false Non-passenger automobile. 523.5 Section 523.5... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.5 Non-passenger automobile. A non-passenger automobile means an automobile that is not a passenger automobile or a work truck and...

  17. 49 CFR 523.5 - Non-passenger automobile.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 6 2013-10-01 2013-10-01 false Non-passenger automobile. 523.5 Section 523.5... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.5 Non-passenger automobile. A non-passenger automobile means an automobile that is not a passenger automobile or a work truck and...

  18. 19 CFR 122.88 - Aircraft carrying domestic (stopover) passengers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Aircraft carrying domestic (stopover) passengers... Passengers § 122.88 Aircraft carrying domestic (stopover) passengers. Airlines that commingle domestic... continuing on another aircraft to a second U.S. destination) with international passengers who are...

  19. 19 CFR 122.88 - Aircraft carrying domestic (stopover) passengers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Aircraft carrying domestic (stopover) passengers... Passengers § 122.88 Aircraft carrying domestic (stopover) passengers. Airlines that commingle domestic... continuing on another aircraft to a second U.S. destination) with international passengers who are...

  20. 46 CFR 176.910 - Passenger Ship Safety Certificate.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Passenger Ship Safety Certificate. 176.910 Section 176..., as Amended (SOLAS) § 176.910 Passenger Ship Safety Certificate. (a) A vessel, which carries more than 12 passengers on an international voyage must have a valid SOLAS Passenger Ship Safety Certificate...

  1. 46 CFR 176.910 - Passenger Ship Safety Certificate.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Passenger Ship Safety Certificate. 176.910 Section 176..., as Amended (SOLAS) § 176.910 Passenger Ship Safety Certificate. (a) A vessel, which carries more than 12 passengers on an international voyage must have a valid SOLAS Passenger Ship Safety Certificate...

  2. 46 CFR 176.910 - Passenger Ship Safety Certificate.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Passenger Ship Safety Certificate. 176.910 Section 176..., as Amended (SOLAS) § 176.910 Passenger Ship Safety Certificate. (a) A vessel, which carries more than 12 passengers on an international voyage must have a valid SOLAS Passenger Ship Safety Certificate...

  3. 46 CFR 176.910 - Passenger Ship Safety Certificate.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Passenger Ship Safety Certificate. 176.910 Section 176..., as Amended (SOLAS) § 176.910 Passenger Ship Safety Certificate. (a) A vessel, which carries more than 12 passengers on an international voyage must have a valid SOLAS Passenger Ship Safety Certificate...

  4. 46 CFR 176.910 - Passenger Ship Safety Certificate.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Passenger Ship Safety Certificate. 176.910 Section 176..., as Amended (SOLAS) § 176.910 Passenger Ship Safety Certificate. (a) A vessel, which carries more than 12 passengers on an international voyage must have a valid SOLAS Passenger Ship Safety Certificate...

  5. Teen Drivers' Perceptions of Their Peer Passengers: Qualitative Study.

    PubMed

    Ehsani, Johnathon P; Haynie, Denise L; Luthers, Christina; Perlus, Jessamyn; Gerber, Eli; Ouimet, Marie Claude; Klauer, Sheila G; Simons-Morton, Bruce

    The presence of peer passengers increases teenage drivers' fatal crash risk. Distraction and social influence are the two main factors that have been associated with increased risk. Teen drivers' perceptions of their peer passengers on these factors could inform our understanding of the conditions under which peer passengers increase crash risk or promote safer driving. The purpose of this study was to examine teen drivers' perceptions of their peer passengers on distraction and social influence. A convenience sample of male and female drivers participated in a semi-structured interview that included questions on their perceptions of the effects of peer passengers on driving on distraction and social influence. The analysis of the interviews was guided by a grounded theory approach. Teenage drivers were aware of the risk that peer passengers posed. Some described having passengers in the vehicle as distracting, and recognized that the level of distraction increased with the number of passengers in the vehicle. Drivers that felt responsible for the safety of their peer passengers described strategies they used to control the in-vehicle environment. Drivers described driving with passengers as a performance, and articulated direct and indirect sources of pressure, gender norms, and unspoken expectations of their passengers as influencing their driving behavior. The influence of passengers is situation specific and dependent on whom the passenger(s) may be. Passenger influence may be either protective or harmful, depending on the circumstances. Some passengers exert direct influence, but often their influence appears more indirect and subtle.

  6. 46 CFR 171.045 - Weight of passengers and crew.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Weight of passengers and crew. 171.045 Section 171.045... PERTAINING TO VESSELS CARRYING PASSENGERS Intact Stability § 171.045 Weight of passengers and crew. (a) This... requirements applicable to each vessel, using a total weight of passengers and crew carried, is based upon an...

  7. 46 CFR 46.05-25 - New passenger vessel.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false New passenger vessel. 46.05-25 Section 46.05-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES SUBDIVISION LOAD LINES FOR PASSENGER VESSELS Definitions Used in This Part § 46.05-25 New passenger vessel. A new passenger vessel is a vessel...

  8. 46 CFR 46.05-25 - New passenger vessel.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false New passenger vessel. 46.05-25 Section 46.05-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES SUBDIVISION LOAD LINES FOR PASSENGER VESSELS Definitions Used in This Part § 46.05-25 New passenger vessel. A new passenger vessel is a vessel...

  9. 46 CFR 46.05-25 - New passenger vessel.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false New passenger vessel. 46.05-25 Section 46.05-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES SUBDIVISION LOAD LINES FOR PASSENGER VESSELS Definitions Used in This Part § 46.05-25 New passenger vessel. A new passenger vessel is a...

  10. 46 CFR 46.05-25 - New passenger vessel.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false New passenger vessel. 46.05-25 Section 46.05-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES SUBDIVISION LOAD LINES FOR PASSENGER VESSELS Definitions Used in This Part § 46.05-25 New passenger vessel. A new passenger vessel is a...

  11. 49 CFR 223.15 - Requirements for existing passenger cars.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Requirements for existing passenger cars. 223.15... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION SAFETY GLAZING STANDARDS-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.15 Requirements for existing passenger cars. (a) Passenger cars built...

  12. 49 CFR 223.15 - Requirements for existing passenger cars.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Requirements for existing passenger cars. 223.15... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION SAFETY GLAZING STANDARDS-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.15 Requirements for existing passenger cars. (a) Passenger cars built...

  13. 49 CFR 223.15 - Requirements for existing passenger cars.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Requirements for existing passenger cars. 223.15... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION SAFETY GLAZING STANDARDS-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.15 Requirements for existing passenger cars. (a) Passenger cars built...

  14. 49 CFR 223.15 - Requirements for existing passenger cars.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Requirements for existing passenger cars. 223.15... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION SAFETY GLAZING STANDARDS-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.15 Requirements for existing passenger cars. (a) Passenger cars built...

  15. 49 CFR 223.15 - Requirements for existing passenger cars.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Requirements for existing passenger cars. 223.15... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION SAFETY GLAZING STANDARDS-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.15 Requirements for existing passenger cars. (a) Passenger cars built...

  16. 19 CFR 122.88 - Aircraft carrying domestic (stopover) passengers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Aircraft carrying domestic (stopover) passengers... Passengers § 122.88 Aircraft carrying domestic (stopover) passengers. Airlines that commingle domestic... continuing on another aircraft to a second U.S. destination) with international passengers who are continuing...

  17. Effects of Doxycycline on gene expression in Wolbachia and Brugia malayi adult female worms in vivo

    PubMed Central

    2012-01-01

    Background Most filarial nematodes contain Wolbachia symbionts. The purpose of this study was to examine the effects of doxycycline on gene expression in Wolbachia and adult female Brugia malayi. Methods Brugia malayi infected gerbils were treated with doxycycline for 6-weeks. This treatment largely cleared Wolbachia and arrested worm reproduction. RNA recovered from treated and control female worms was labeled by random priming and hybridized to the Version 2- filarial microarray to obtain expression profiles. Results and discussion Results showed significant changes in expression for 200 Wolbachia (29% of Wolbachia genes with expression signals in untreated worms) and 546 B. malayi array elements after treatment. These elements correspond to known genes and also to novel genes with unknown biological functions. Most differentially expressed Wolbachia genes were down-regulated after treatment (98.5%). In contrast, doxycycline had a mixed effect on B. malayi gene expression with many more genes being significantly up-regulated after treatment (85% of differentially expressed genes). Genes and processes involved in reproduction (gender-regulated genes, collagen, amino acid metabolism, ribosomal processes, and cytoskeleton) were down-regulated after doxycycline while up-regulated genes and pathways suggest adaptations for survival in response to stress (energy metabolism, electron transport, anti-oxidants, nutrient transport, bacterial signaling pathways, and immune evasion). Conclusions Doxycycline reduced Wolbachia and significantly decreased bacterial gene expression. Wolbachia ribosomes are believed to be the primary biological target for doxycycline in filarial worms. B. malayi genes essential for reproduction, growth and development were also down-regulated; these changes are consistent with doxycycline effects on embryo development and reproduction. On the other hand, many B. malayi genes involved in energy production, electron-transport, metabolism, anti

  18. Wolbachia infections in Anopheles gambiae cells: transcriptomic characterization of a novel host-symbiont interaction.

    PubMed

    Hughes, Grant L; Ren, Xiaoxia; Ramirez, Jose L; Sakamoto, Joyce M; Bailey, Jason A; Jedlicka, Anne E; Rasgon, Jason L

    2011-02-01

    The endosymbiotic bacterium Wolbachia is being investigated as a potential control agent in several important vector insect species. Recent studies have shown that Wolbachia can protect the insect host against a wide variety of pathogens, resulting in reduced transmission of parasites and viruses. It has been proposed that compromised vector competence of Wolbachia-infected insects is due to up-regulation of the host innate immune system or metabolic competition. Anopheles mosquitoes, which transmit human malaria parasites, have never been found to harbor Wolbachia in nature. While transient somatic infections can be established in Anopheles, no stable artificially-transinfected Anopheles line has been developed despite numerous attempts. However, cultured Anopheles cells can be stably infected with multiple Wolbachia strains such as wAlbB from Aedes albopictus, wRi from Drosophila simulans and wMelPop from Drosophila melanogaster. Infected cell lines provide an amenable system to investigate Wolbachia-Anopheles interactions in the absence of an infected mosquito strain. We used Affymetrix GeneChip microarrays to investigate the effect of wAlbB and wRi infection on the transcriptome of cultured Anopheles Sua5B cells, and for a subset of genes used quantitative PCR to validate results in somatically-infected Anopheles mosquitoes. Wolbachia infection had a dramatic strain-specific effect on gene expression in this cell line, with almost 700 genes in total regulated representing a diverse array of functional classes. Very strikingly, infection resulted in a significant down-regulation of many immune, stress and detoxification-related transcripts. This is in stark contrast to the induction of immune genes observed in other insect hosts. We also identified genes that may be potentially involved in Wolbachia-induced reproductive and pathogenic phenotypes. Somatically-infected mosquitoes had similar responses to cultured cells. The data show that Wolbachia has a profound

  19. Wolbachia Infections in Anopheles gambiae Cells: Transcriptomic Characterization of a Novel Host-Symbiont Interaction

    PubMed Central

    Hughes, Grant L.; Ren, Xiaoxia; Ramirez, Jose L.; Sakamoto, Joyce M.; Bailey, Jason A.; Jedlicka, Anne E.; Rasgon, Jason L.

    2011-01-01

    The endosymbiotic bacterium Wolbachia is being investigated as a potential control agent in several important vector insect species. Recent studies have shown that Wolbachia can protect the insect host against a wide variety of pathogens, resulting in reduced transmission of parasites and viruses. It has been proposed that compromised vector competence of Wolbachia-infected insects is due to up-regulation of the host innate immune system or metabolic competition. Anopheles mosquitoes, which transmit human malaria parasites, have never been found to harbor Wolbachia in nature. While transient somatic infections can be established in Anopheles, no stable artificially-transinfected Anopheles line has been developed despite numerous attempts. However, cultured Anopheles cells can be stably infected with multiple Wolbachia strains such as wAlbB from Aedes albopictus, wRi from Drosophila simulans and wMelPop from Drosophila melanogaster. Infected cell lines provide an amenable system to investigate Wolbachia-Anopheles interactions in the absence of an infected mosquito strain. We used Affymetrix GeneChip microarrays to investigate the effect of wAlbB and wRi infection on the transcriptome of cultured Anopheles Sua5B cells, and for a subset of genes used quantitative PCR to validate results in somatically-infected Anopheles mosquitoes. Wolbachia infection had a dramatic strain-specific effect on gene expression in this cell line, with almost 700 genes in total regulated representing a diverse array of functional classes. Very strikingly, infection resulted in a significant down-regulation of many immune, stress and detoxification-related transcripts. This is in stark contrast to the induction of immune genes observed in other insect hosts. We also identified genes that may be potentially involved in Wolbachia-induced reproductive and pathogenic phenotypes. Somatically-infected mosquitoes had similar responses to cultured cells. The data show that Wolbachia has a profound

  20. Mutual exclusion of Asaia and Wolbachia in the reproductive organs of mosquito vectors.

    PubMed

    Rossi, Paolo; Ricci, Irene; Cappelli, Alessia; Damiani, Claudia; Ulissi, Ulisse; Mancini, Maria Vittoria; Valzano, Matteo; Capone, Aida; Epis, Sara; Crotti, Elena; Chouaia, Bessem; Scuppa, Patrizia; Joshi, Deepak; Xi, Zhiyong; Mandrioli, Mauro; Sacchi, Luciano; O'Neill, Scott L; Favia, Guido

    2015-05-17

    Wolbachia is a group of intracellular maternally inherited bacteria infecting a high number of arthropod species. Their presence in different mosquito species has been largely described, but Aedes aegypti, the main vector of Dengue virus, has never been found naturally infected by Wolbachia. Similarly, malaria vectors and other anophelines are normally negative to Wolbachia, with the exception of an African population where these bacteria have recently been detected. Asaia is an acetic acid bacterium stably associated with several mosquito species, found as a dominant microorganism of the mosquito microbiota. Asaia has been described in gut, salivary glands and in reproductive organs of adult mosquitoes in Ae. aegypti and in anophelines. It has recently been shown that Asaia may impede vertical transmission of Wolbachia in Anopheles mosquitoes. Here we present an experimental study, aimed at determining whether there is a negative interference between Asaia and Wolbachia, for the gonad niche in mosquitoes. Different methods (PCR and qPCR, monoclonal antibody staining and FISH) have been used to address the question of the co-localization and the relative presence/abundance of the two symbionts. PCR and qPCR were performed to qualitatively and quantitatively verify the distribution of Asaia and Wolbachia in different mosquito species/organs. Monoclonal antibody staining and FISH were performed to localize the symbionts in different mosquito species. Here we provide evidence that, in Anopheles and in other mosquitoes, there is a reciprocal negative interference between Asaia and Wolbachia symbionts, in terms of the colonization of the gonads. In particular, we have shown that in some mosquito species the presence of one of the symbionts prevented the establishment of the second, while in other systems the symbionts were co-localized, although at reduced densities. A mutual exclusion or a competition between Asaia and Wolbachia may contribute to explain the inability

  1. High Pressure Freezing/Freeze Substitution Fixation Improves the Ultrastructural Assessment of Wolbachia Endosymbiont – Filarial Nematode Host Interaction

    PubMed Central

    Fischer, Kerstin; Beatty, Wandy L.; Weil, Gary J.; Fischer, Peter U.

    2014-01-01

    Background Wolbachia α-proteobacteria are essential for growth, reproduction and survival for many filarial nematode parasites of medical and veterinary importance. Endobacteria were discovered in filarial parasites by transmission electron microscopy in the 1970’s using chemically fixed specimens. Despite improvements of fixation and electron microscopy techniques during the last decades, methods to study the Wolbachia/filaria interaction on the ultrastructural level remained unchanged and the mechanisms for exchange of materials and for motility of endobacteria are not known. Methodology/Principal Finding We used high pressure freezing/freeze substitution to improve fixation of Brugia malayi and its endosymbiont, and this led to improved visualization of different morphological forms of Wolbachia. The three concentric, bilayer membranes that surround the endobacterial cytoplasm were well preserved. Vesicles with identical membrane structures were identified close to the endobacteria, and multiple bacteria were sometimes enclosed within a single outer membrane. Immunogold electron microscopy using a monoclonal antibody directed against Wolbachia surface protein-1 labeled the membranes that enclose Wolbachia and Wolbachia-associated vesicles. High densities of Wolbachia were observed in the lateral chords of L4 larvae, immature, and mature adult worms. Extracellular Wolbachia were sometimes present in the pseudocoelomic cavity near the developing female reproductive organs. Wolbachia-associated actin tails were not observed. Wolbachia motility may be explained by their residence within vacuoles, as they may co-opt the host cell’s secretory pathway to move within and between cells. Conclusions/Significance High pressure freezing/freeze substitution significantly improved the preservation of filarial tissues for electron microscopy to reveal membranes and sub cellular structures that could be crucial for exchange of materials between Wolbachia and its host. PMID

  2. Identifying influential and susceptible members of social networks.

    PubMed

    Aral, Sinan; Walker, Dylan

    2012-07-20

    Identifying social influence in networks is critical to understanding how behaviors spread. We present a method that uses in vivo randomized experimentation to identify influence and susceptibility in networks while avoiding the biases inherent in traditional estimates of social contagion. Estimation in a representative sample of 1.3 million Facebook users showed that younger users are more susceptible to influence than older users, men are more influential than women, women influence men more than they influence other women, and married individuals are the least susceptible to influence in the decision to adopt the product offered. Analysis of influence and susceptibility together with network structure revealed that influential individuals are less susceptible to influence than noninfluential individuals and that they cluster in the network while susceptible individuals do not, which suggests that influential people with influential friends may be instrumental in the spread of this product in the network.

  3. 46 CFR 176.113 - Passengers permitted.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... equipment or line handling gear, in the way of sail booms, running rigging, or paddle wheels, or along... of sail booms or running rigging; (v) Spaces below deck that are unsuitable for passengers or...

  4. 46 CFR 176.113 - Passengers permitted.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... equipment or line handling gear, in the way of sail booms, running rigging, or paddle wheels, or along... of sail booms or running rigging; (v) Spaces below deck that are unsuitable for passengers or...

  5. 46 CFR 176.113 - Passengers permitted.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... equipment or line handling gear, in the way of sail booms, running rigging, or paddle wheels, or along... of sail booms or running rigging; (v) Spaces below deck that are unsuitable for passengers or...

  6. 46 CFR 176.113 - Passengers permitted.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... or line handling gear, in the way of sail booms, running rigging, or paddle wheels, or along pulpits... of sail booms or running rigging; (v) Spaces below deck that are unsuitable for passengers or...

  7. Optimal boarding method for airline passengers

    SciTech Connect

    Steffen, Jason H.; /Fermilab

    2008-02-01

    Using a Markov Chain Monte Carlo optimization algorithm and a computer simulation, I find the passenger ordering which minimizes the time required to board the passengers onto an airplane. The model that I employ assumes that the time that a passenger requires to load his or her luggage is the dominant contribution to the time needed to completely fill the aircraft. The optimal boarding strategy may reduce the time required to board and airplane by over a factor of four and possibly more depending upon the dimensions of the aircraft. I explore some features of the optimal boarding method and discuss practical modifications to the optimal. Finally, I mention some of the benefits that could come from implementing an improved passenger boarding scheme.

  8. 75 FR 26839 - Metrics and Standards for Intercity Passenger Rail Service under Section 207 of the Passenger...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ... performance and service quality of intercity passenger train operations. In compliance with the statute, the FRA and Amtrak jointly drafted performance metrics and standards for intercity passenger rail service...-0016] Metrics and Standards for Intercity Passenger Rail Service under Section 207 of the Passenger...

  9. 49 CFR 238.307 - Periodic mechanical inspection of passenger cars and unpowered vehicles used in passenger trains.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Periodic mechanical inspection of passenger cars... Passenger Equipment § 238.307 Periodic mechanical inspection of passenger cars and unpowered vehicles used in passenger trains. (a) General. (1) Railroads shall conduct periodic mechanical inspections of all...

  10. 49 CFR 238.307 - Periodic mechanical inspection of passenger cars and unpowered vehicles used in passenger trains.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Periodic mechanical inspection of passenger cars... Passenger Equipment § 238.307 Periodic mechanical inspection of passenger cars and unpowered vehicles used in passenger trains. (a) General. (1) Railroads shall conduct periodic mechanical inspections of all...

  11. Locating influential nodes via dynamics-sensitive centrality.

    PubMed

    Liu, Jian-Guo; Lin, Jian-Hong; Guo, Qiang; Zhou, Tao

    2016-02-24

    With great theoretical and practical significance, locating influential nodes of complex networks is a promising issue. In this paper, we present a dynamics-sensitive (DS) centrality by integrating topological features and dynamical properties. The DS centrality can be directly applied in locating influential spreaders. According to the empirical results on four real networks for both susceptible-infected-recovered (SIR) and susceptible-infected (SI) spreading models, the DS centrality is more accurate than degree, k-shell index and eigenvector centrality.

  12. The impact of interior cabin noise on passenger acceptance

    NASA Technical Reports Server (NTRS)

    Rudrapatna, A. N.; Jacobson, I. D.

    1976-01-01

    Based on flight test data gathered in general aviation aircraft, a composite motion-noise passenger comfort model has been developed which enables the assessment of cabin interior noise impact on passenger acceptance. Relationships between special subject responses and passenger responses are given, as well as the effect of comfort on passenger acceptance. The importance of comfort and noise on the overall passenger reaction is discussed.

  13. The distribution of Wolbachia in Cubitermes (Termitidae, Termitinae) castes and colonies: a modelling approach.

    PubMed

    Roy, Virginie; Girondot, Marc; Harry, Myriam

    2015-01-01

    Wolbachia are endosymbiotic bacteria of arthropods and nematodes that are able to manipulate host reproduction. Although vertically transmitted via the cytoplasm in eggs, horizontal transmission of Wolbachia among and within arthropod species has been shown to be common. Eusocial insects represent interesting models for studying Wolbachia transmission due to colonial organization and close interaction between nestmates. Here we conducted a detailed screening of Wolbachia infection for 15 colonies of the very common soil-feeding termites Cubitermes spp. affinis subarquatus (Termitidae, Termitinae) that consist of four distinct phylogenetic species in the Lopé forest Reserve, Gabon. Infection tests showed that 50% of the individuals were Wolbachia positive (N = 555) with 90% of reproductives and 48% of offspring infected. White soldiers, which are transitional stages preceding mature soldiers, had a significantly higher mean infection rate (74%) than the other castes and stages (63%, 33% and 39% for larvae, workers and mature soldiers, respectively). We used a maximum likelihood method and Akaike's Information Criterion in order to explain the non-expected high rate of Wolbachia infection in white soldiers. The best model included a species effect for the stochastic loss of Wolbachia and a caste effect for the rate of gain. After fitting, the best model selected was for a species-specific rate of loss with a null rate of new gain for larvae, workers and soldiers and a probability of 0.72 whatever the species, that a white soldier becomes newly contaminated during that stage. The mean expected infection rate in white soldiers without a new gain was estimated to 17% instead of the 74% observed. Here we discuss the possible explanations to the high infection rate observed in white soldiers.

  14. The Distribution of Wolbachia in Cubitermes (Termitidae, Termitinae) Castes and Colonies: A Modelling Approach

    PubMed Central

    Roy, Virginie; Girondot, Marc; Harry, Myriam

    2015-01-01

    Wolbachia are endosymbiotic bacteria of arthropods and nematodes that are able to manipulate host reproduction. Although vertically transmitted via the cytoplasm in eggs, horizontal transmission of Wolbachia among and within arthropod species has been shown to be common. Eusocial insects represent interesting models for studying Wolbachia transmission due to colonial organization and close interaction between nestmates. Here we conducted a detailed screening of Wolbachia infection for 15 colonies of the very common soil-feeding termites Cubitermes spp. affinis subarquatus (Termitidae, Termitinae) that consist of four distinct phylogenetic species in the Lopé forest Reserve, Gabon. Infection tests showed that 50% of the individuals were Wolbachia positive (N = 555) with 90% of reproductives and 48% of offspring infected. White soldiers, which are transitional stages preceding mature soldiers, had a significantly higher mean infection rate (74%) than the other castes and stages (63%, 33% and 39% for larvae, workers and mature soldiers, respectively). We used a maximum likelihood method and Akaike’s Information Criterion in order to explain the non-expected high rate of Wolbachia infection in white soldiers. The best model included a species effect for the stochastic loss of Wolbachia and a caste effect for the rate of gain. After fitting, the best model selected was for a species-specific rate of loss with a null rate of new gain for larvae, workers and soldiers and a probability of 0.72 whatever the species, that a white soldier becomes newly contaminated during that stage. The mean expected infection rate in white soldiers without a new gain was estimated to 17% instead of the 74% observed. Here we discuss the possible explanations to the high infection rate observed in white soldiers. PMID:25671520

  15. Population genetics of Wolbachia-infected, parthenogenetic and uninfected, sexual populations of Tetrastichus coeruleus (Hymenoptera: Eulophidae).

    PubMed

    Reumer, Barbara M; van Alphen, Jacques J M; Kraaijeveld, Ken

    2013-09-01

    Wolbachia are endosymbiotic bacteria known to manipulate the reproduction of their hosts. These manipulations are expected to have consequences on the population genetics of the host, such as heterozygosity levels, genetic diversity and gene flow. The parasitoid wasp Tetrastichus coeruleus has populations that are infected with parthenogenesis-inducing Wolbachia and populations that are not infected. We studied the population genetics of T. coeruleus between and within Wolbachia-infected and uninfected populations, using nuclear microsatellites and mitochondrial DNA. We expected reduced genetic diversity in both DNA types in infected populations. However, migration and gene flow could introduce new DNA variants into populations. We therefore paid special attention to individuals with unexpected (genetic) characteristics. Based on nuclear and mitochondrial DNA, two genetic clusters were evident: a thelytokous cluster containing all Wolbachia-infected, parthenogenetic populations and an arrhenotokous cluster containing all uninfected, sexual populations. Nuclear and mitochondrial DNA did not exhibit concordant patterns of variation, although there was reduced genetic diversity in infected populations for both DNA types. Within the thelytokous cluster, there was nuclear DNA variation, but no mitochondrial DNA variation. This nuclear DNA variation may be explained by occasional sex between infected females and males, by horizontal transmission of Wolbachia, and/or by novel mutations. Several females from thelytokous populations were uninfected and/or heterozygous for microsatellite loci. These unexpected characteristics may be explained by migration, by inefficient transmission of Wolbachia, by horizontal transmission of Wolbachia, and/or by novel mutations. However, migration has not prevented the build-up of considerable genetic differentiation between thelytokous and arrhenotokous populations. © 2013 John Wiley & Sons Ltd.

  16. Evolution of Wolbachia-induced cytoplasmic incompatibility in Drosophila simulans and D. sechellia.

    PubMed

    Charlat, Sylvain; Nirgianaki, Androniki; Bourtzis, Kostas; Merçot, Hervé

    2002-09-01

    The intracellular bacterium Wolbachia invades arthropod host populations through various mechanisms, the most common of which being cytoplasmic incompatibility (CI). CI involves elevated embryo mortality when infected males mate with uninfected females or females infected with different, incompatible Wolbachia strains. The present study focuses on this phenomenon in two Drosophila species: D. simulans and D. sechellia. Drosophila simulans populations are infected by several Wolbachia strains, including wHa and wNo. Drosophila sechellia is infected by only two Wolbachia: wSh and wSn. In both Drosophila species, double infections with Wolbachia are found. As indicated by several molecular markers, wHa is closely related to wSh, and wNo to wSn. Furthermore, the double infections in the two host species are associated with closely related mitochondrial haplotypes, namely siI (associated with wHa and wNo in D. simulans) and se (associated with wSh and wSn in D. sechellia). To test the theoretical prediction that Wolbachia compatibility types can diverge rapidly, we injected wSh and wSn into D. simulans, to compare their CI properties to those of their sister strains wHa and wNo, respectively, in the same host genetic background. We found that within each pair of sister strains CI levels were similar and that sister strains were fully compatible. We conclude that the short period for which the Wolbachia sister strains have been evolving separated from each other was not sufficient for their CI properties to diverge significantly.

  17. Widespread infection and diverse infection patterns of Wolbachia in Chinese aphids.

    PubMed

    Wang, Zhe; Su, Xiao-Min; Wen, Juan; Jiang, Li-Yun; Qiao, Ge-Xia

    2014-06-01

    Wolbachia are intracellular symbionts that infect a wide range of arthropods and filarial nematodes. Aphids are engaged in diverse and complex relationships with their endosymbionts. Four supergroups (A, B, M and N) of Wolbachia were previously detected in aphids and supergroups M and N were only found in aphids. In this study, we detected and described Wolbachia infections in natural populations of aphids in China. Three supergroups (A, B and M) were found in the examined aphid species. Supergroup M was preponderant, whereas supergroups A and B were only detected in certain species. Supergroup N was not found in this study. There were four infection patterns of Wolbachia in aphids, namely, infection with supergroup M alone, co-infection with supergroups A and M, co-infection with supergroups B and M, and co-infection with supergroups A, B and M. The pattern of infection only with supergroup M was universal and was found in all evaluated subfamilies. Only two subfamilies, Aphidinae and Lachninae, manifested to present all four infection patterns. Three patterns were observed in Calaphidinae (M, A&M, B&M) and Eriosomatinae (M, B&M, A&B&M). Two patterns were observed in the Anoeciinae (M, A&M) and Greenideinae (M, B&M), and only one pattern (M) was observed in the remaining families and/or subfamilies of Aphidoidea. These results indicated that Wolbachia infections in Chinese aphids are widespread. Phylogenetic analyses suggest that Wolbachia supergroup M spread rapidly and recently among all host species of aphids in China. Reasons for this spread and its mechanisms are discussed along with the possible effects of Wolbachia on their aphid hosts.

  18. Diet-Induced Nutritional Stress and Pathogen Interference in Wolbachia-Infected Aedes aegypti

    PubMed Central

    Caragata, Eric Pearce; Rezende, Fernanda Oliveira; Simões, Taynãna César; Moreira, Luciano Andrade

    2016-01-01

    The pathogen interference phenotype greatly restricts infection with dengue virus (DENV) and other pathogens in Wolbachia-infected Aedes aegypti, and is a vital component of Wolbachia-based mosquito control. Critically, the phenotype’s causal mechanism is complex and poorly understood, with recent evidence suggesting that the cause may be species specific. To better understand this important phenotype, we investigated the role of diet-induced nutritional stress on interference against DENV and the avian malarial parasite Plasmodium gallinaceum in Wolbachia-infected Ae. aegypti, and on physiological processes linked to the phenotype. Wolbachia-infected mosquitoes were fed one of four different concentrations of sucrose, and then challenged with either P. gallinaceum or DENV. Interference against P. gallinaceum was significantly weakened by the change in diet however there was no effect on DENV interference. Immune gene expression and H2O2 levels have previously been linked to pathogen interference. These traits were assayed for mosquitoes on each diet using RT-qPCR and the Amplex Red Hydrogen Peroxide/Peroxidase Assay Kit, and it was observed that the change in diet did not significantly affect immune expression, but low carbohydrate levels led to a loss of ROS induction in Wolbachia-infected mosquitoes. Our data suggest that host nutrition may not influence DENV interference for Wolbachia-infected mosquitoes, but Plasmodium interference may be linked to both nutrition and oxidative stress. This pathogen-specific response to nutritional change highlights the complex nature of interactions between Wolbachia and pathogens in mosquitoes. PMID:27893736

  19. Sex and stripping: The key to the intimate relationship between Wolbachia and host?

    PubMed

    Negri, Ilaria; Pellecchia, Marco; Grève, Pierre; Daffonchio, Daniele; Bandi, Claudio; Alma, Alberto

    2010-03-01

    Wolbachia pipientis is known to infect only arthropods and nematodes (mainly filarial worms). A unique feature shared by the two Phyla is the ability to replace the exoskeleton, a process known as ecdysis. This shared characteristic is thought to reflect a common ancestry. Arthropod moulting is induced by the steroid hormone 20-hydroxyecdysone (20E) and a role for ecdysteroids in nematode ecdysis has also been suggested. Removing Wolbachia from filarial worms impairs the host's development. From analyses of the genome of Wolbachia harbored by the filarial nematode Brugia malayi and that of its host, the bacterium may provide a source of heme, an essential component of cytochrome P450's that are necessary for steroid hormone biosynthetic pathways.In arthropods, Wolbachia is a reproductive manipulator, inducing various phenotypic effects that may be due to differences in host physiology, in particular, endocrine-related processes governing development and reproduction. Insect steroids have well-defined roles in the coordination of multiple developmental processes, and in adults they control important aspects of reproduction, including ovarian development, oogenesis, sexual behavior, and in some taxa vitellogenin biosynthesis.According to some authors ecdysteroids may also act as sex hormones. In insects sex differentiation is generally thought to be a strictly genetic process, in which each cell decides its own sexual fate based on its sex chromosome constitution, but, surprisingly, recent data demonstrate that in Drosophila sex determination is not cell-autonomous, as it happens in mammals. Thus the presence of signals coordinating the development of a gender-specific phenotype cannot be excluded.This could explain why Wolbachia interferes with insect reproduction; and also could explain why Wolbachia interferes with insect development.Thus, is "sex (=reproduction) and stripping (=ecdysis)" the key to the intimate relationship between Wolbachia and its host?

  20. Influential sources affecting Bangkok adolescent body image perceptions.

    PubMed

    Thianthai, Chulanee

    2006-01-01

    The study of body image-related problems in non-Western countries is still very limited. Thus, this study aims to identify the main influential sources and show how they affect the body image perceptions of Bangkok adolescents. The researcher recruited 400 Thai male and female adolescents in Bangkok, attending high school to freshmen level, ranging from 16-19 years, to participate in this study. Survey questionnaires were distributed to every student and follow-up interviews conducted with 40 students. The findings showed that there are eight main influential sources respectively ranked from the most influential to the least influential: magazines, television, peer group, familial, fashion trend, the opposite gender, self-realization and health knowledge. Similar to those studies conducted in Western countries, more than half of the total percentage was the influence of mass media and peer groups. Bangkok adolescents also internalized Western ideal beauty through these mass media channels. Alike studies conducted in the West, there was similarities in the process of how these influential sources affect Bangkok adolescent body image perception, with the exception of familial source. In conclusion, taking the approach of identifying the main influential sources and understanding how they affect adolescent body image perceptions can help prevent adolescents from having unhealthy views and taking risky measures toward their bodies. More studies conducted in non-Western countries are needed in order to build a cultural sensitive program, catered to the body image problems occurring in adolescents within that particular society.

  1. Deleterious Passengers in Adapting Populations

    PubMed Central

    Good, Benjamin H.; Desai, Michael M.

    2014-01-01

    Most new mutations are deleterious and are eventually eliminated by natural selection. But in an adapting population, the rapid amplification of beneficial mutations can hinder the removal of deleterious variants in nearby regions of the genome, altering the patterns of sequence evolution. Here, we analyze the interactions between beneficial “driver” mutations and linked deleterious “passengers” during the course of adaptation. We derive analytical expressions for the substitution rate of a deleterious mutation as a function of its fitness cost, as well as the reduction in the beneficial substitution rate due to the genetic load of the passengers. We find that the fate of each deleterious mutation varies dramatically with the rate and spectrum of beneficial mutations and the deleterious substitution rate depends nonmonotonically on the population size and the rate of adaptation. By quantifying this dependence, our results allow us to estimate which deleterious mutations will be likely to fix and how many of these mutations must arise before the progress of adaptation is significantly reduced. PMID:25194161

  2. Effects of parasitic sex-ratio distorters on host genetic structure in the Armadillidium vulgare-Wolbachia association.

    PubMed

    Verne, S; Johnson, M; Bouchon, D; Grandjean, F

    2012-02-01

    In the pill bug Armadillidium vulgare (Crustacea, Oniscidea), Wolbachia facilitates its spread through vertical transmission via the eggs by inducing feminization of genetic males. The spread of feminizing Wolbachia within and across populations is therefore expected to influence mitochondrial DNA (mtDNA) genetic structure by hitchhiking. To test this hypothesis, we analysed nuclear and mtDNA genetic structure, and Wolbachia prevalence in 13 populations of the pill bug host. Wolbachia prevalence (ranging from 0% to 100% of sampled females) was highly variable among populations. All three Wolbachia strains previously observed in A. vulgare were present (wVulC, wVulM and wVulP) with wVulC being the most prevalent (nine of 13 populations). The host showed a genetic structure on five microsatellite loci that is compatible with isolation by distance. The strong genetic structure observed on host mtDNA was correlated with Wolbachia prevalence: three mitotypes were in strong linkage disequilibrium with the three strains of Wolbachia. Neutrality tests showed that the mtDNA polymorphism is not neutral, and we thus suggest that this unusual pattern of mtDNA polymorphism found in A. vulgare was due to Wolbachia.

  3. Variable Infection Frequency and High Diversity of Multiple Strains of Wolbachia pipientis in Perkinsiella Planthoppers ▿ †

    PubMed Central

    Hughes, G. L.; Allsopp, P. G.; Brumbley, S. M.; Woolfit, M.; McGraw, E. A.; O'Neill, S. L.

    2011-01-01

    This survey of Wolbachia infections in populations of the planthoppers Perkinsiella saccharicida and Perkinsiella vitiensis revealed variable frequencies, low-titer infections, and high phylogenetic diversities of strains. These observations add to the growing realization that Wolbachia infections may be extremely common within invertebrates and yet occur infrequently within populations and at low titer within individuals. PMID:21278277

  4. Rapid and non-destructive detection and identification two strains of Wolbachia in Aedes aegypti by near-infrared spectroscopy

    USDA-ARS?s Scientific Manuscript database

    We investigated the potential of using near-infrared spectroscopy (NIRS) to detect the presence of Wolbachia pipientis (wMel) in male and female laboratory-reared Aedes aegypti mosquitoes. The release of Wolbachia transinfected mosquitoes is likely to form a key component of disease control strategi...

  5. Incomplete removal of Wolbachia with tetracycline has two-edged reproductive effects in the thelytokous wasp Encarsia formosa (Hymenoptera: Aphelinidae)

    PubMed Central

    Wang, Xiao-Xiang; Qi, Lan-Da; Jiang, Rui; Du, Yu-Zhou; Li, Yuan-Xi

    2017-01-01

    Wolbachia pipientis are intracellular endosymbionts that induce parthenogenesis in the parasitoid Encarsia formosa. Previous studies that focused on effects of Wolbachia on the wasp usually used tetracycline to remove Wolbachia without concern for the joint influences of tetracycline and Wolbachia. Here we treated the wasps (F0 lines) with tetracycline to produce offspring (F1 lines) which were not fed tetracycline to avoid antibiotic influence. The quantitative data and fluorescence in situ hybridization showed that Wolbachia titers were reduced but not totally removed. The Wolbachia that infected the male offspring were unpredictably detected. Low dose tetracycline enhanced the fertility of 2-day-old F0 wasps after 24 h of treatment; however, compared with controls, the oocyte load of 3- to 6-day-old tetracycline-treated wasps decreased day by day, and tetracycline reduced the longevity of the wasps. The fecundity of controls was significantly higher than that of the treated F1-10 and F1-20 generations. Gene expression of vitellogenin reflected the same trend as that of wasp fecundities in both F0 and F1 lines. Moreover, female offspring proportions of F0 and F1 lines were related to the titer of infected Wolbachia, demonstrating that Wolbachia titer affected the sex determination of E. formosa. PMID:28266601

  6. Wolbachia effects on host fitness and the influence of male aging on cytoplasmic incompatibility in Aedes polynesiensis (Diptera: Culicidae).

    PubMed

    Brelsfoard, C L; Dobson, S L

    2011-09-01

    The endosymbiotic bacteria Wolbachia manipulate host reproduction by inducing a form of sterility known as cytoplasmic incompatibility (CI), promoting the invasion of infection into natural host populations. CI has received attention for use in applied strategies to control insect vectors of disease. Thus, to understand both naturally occurring Wolbachia invasions and evaluate potential applied strategies, it is important to understand Wolbachia interactions with its host, including impacts on fitness and the CI level. In this study, we examined for an effect of Wolbachia on survivorship, developmental time, sex ratio, longevity, fecundity, and egg hatch of Aedes polynesiensis Marks, which is the primary vector of Wuchereria bancrofti in the South Pacific. In this study, we have compared strains of A. polynesiensis that are naturally and artificially infected with Wolbachia and additional strains that are aposymbiotic (Wolbachia removed to generate an uninfected strain). Artificially infected strains were observed to have increased larval mortality and decreased adult longevity when compared with aposymbiotic strains. Naturally infected strains were observed to have decreased larval mortality, pupal mortality, increased adult longevity, and a larger adult size when compared with aposymbiotic strains. Artificially infected males that were 4 wk old were able to induce high rates of CI, similar to young males. We discuss the results in relation to the natural spread of Wolbachia and Wolbachia-based applied strategies to modify A. polynesiensis populations.

  7. The effect of Wolbachia on dengue dynamics in the presence of two serotypes of dengue: symmetric and asymmetric epidemiological characteristics.

    PubMed

    Ndii, M Z; Allingham, D; Hickson, R I; Glass, K

    2016-10-01

    An innovative strategy to reduce dengue transmission uses the bacterium Wolbachia. We analysed the effects of Wolbachia on dengue transmission dynamics in the presence of two serotypes of dengue using a mathematical model, allowing for differences in the epidemiological characteristics of the serotypes. We found that Wolbachia has a greater effect on secondary infections than on primary infections across a range of epidemiological characteristics. If one serotype is more transmissible than the other, it will dominate primary infections and Wolbachia will be less effective at reducing secondary infections of either serotype. Differences in the antibody-dependent enhancement of the two serotypes have considerably less effect on the benefits of Wolbachia than differences in transmission probability. Even if the antibody-dependent enhancement rate is high, Wolbachia is still effective in reducing dengue. Our findings suggest that Wolbachia will be effective in the presence of more than one serotype of dengue; however, a better understanding of serotype-specific differences in transmission probability may be needed to optimize delivery of a Wolbachia intervention.

  8. A short, high-temperature treatment of host larvae to analyze Wolbachia-host interactions in the moth Ostrinia scapulalis.

    PubMed

    Sugimoto, Takafumi N; Kayukawa, Takumi; Matsuo, Takashi; Tsuchida, Tsutomu; Ishikawa, Yukio

    2015-10-01

    Maternally inherited endosymbiotic bacteria of the genus Wolbachia cause various reproductive alterations in their hosts. Wolbachia induces male-specific death during embryonic and larval stages in the moth Ostrinia scapulalis. To investigate how the density of Wolbachia affects their performance in the host, we attempted to reduce its density using a short, high-temperature treatment of the host at the larval stage. Individuals cured of infection as well as sexual mosaics, which harbor Wolbachia, were obtained by this method in the next generation. The sex of uninfected offspring was exclusively male, similar to that of the offspring of larvae treated with antibiotics. A strong correlation was found between Wolbachia density in female moths and the sex ratio of their progeny. These results suggest that a short, high-temperature treatment at the larval stage reduced the density of Wolbachia in the adult stage, and, hence, inhibited interference with the host's development in the next generation. Since the direct effects of the heat treatment on Wolbachia were transient, this method may be useful for specifying the critical time for interference by Wolbachia in host development. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Wolbachia wsp gene clones detect the distribution of Wolbachia variants and wsp hypervariable regions among individuals of a multistrain infected population of Diabrotica barberi (Coleoptera: Chrysomelidae)

    USDA-ARS?s Scientific Manuscript database

    The northern corn rootworm (Diabrotica barberi) in eastern and central North America exhibits at least three distinct populations with respect to Wolbachia infection: uninfected; singly-infected; multi-infected. The infected states are associated with different mtDNA haplotypes and reduced mtDNA var...

  10. Male-killing Wolbachia and mitochondrial selective sweep in a migratory African insect

    PubMed Central

    2012-01-01

    Background Numerous recent studies have shown that resident symbiotic microorganisms of insects play a fundamental role in host ecology and evolution. The lepidopteran pest, African armyworm (Spodoptera exempta), is a highly migratory and destructive species found throughout sub-Saharan Africa, that can experience eruptive outbreaks within the space of a single generation, making predicting population dynamics and pest control forecasting extremely difficult. Three strains of Wolbachia have recently been identified infecting this species in populations sampled from Tanzania. In this study, we examined the interaction between Wolbachia pipiensis infections and the co-inherited marker, mtDNA, within populations of armyworm, as a means to investigate the population biology and evolutionary history of Wolbachia and its host. Results A Wolbachia-infected isofemale line was established in the laboratory. Phenotypic studies confirmed the strain wExe1 as a male-killer. Partial sequencing of the mitochondrial COI gene from 164 individual field-collected armyworm of known infection status revealed 17 different haplotypes. There was a strong association between Wolbachia infection status and mtDNA haplotype, with a single dominant haplotype, haplo1 (90.2% prevalence), harbouring the endosymbiont. All three Wolbachia strains were associated with this haplotype. This indicates that Wolbachia may be driving a selective sweep on armyworm haplotype diversity. Despite very strong biological and molecular evidence that the samples represent a single species (including from nuclear 28S gene markers), the 17 haplotypes did not fall into a monophyletic clade within the Spodoptera genus; with six haplotypes (2 each from 3 geographically separate populations) differing by >11% in their nucleotide sequence to the other eleven. Conclusions This study suggests that three strains of Wolbachia may be driving a selective sweep on armyworm haplotype diversity, and that based on COI sequence

  11. Wolbachia infections in mosquitoes and their predators inhabiting rice field communities in Thailand and China.

    PubMed

    Wiwatanaratanabutr, Itsanun; Zhang, Chongxing

    2016-07-01

    Wolbachia are inherited, endocytoplasmic bacteria that infect a wide range of arthropods. Here is the first systematic report on the study of Wolbachia infection in mosquitoes and their predators from both Thailand and China. In Thailand, 632 mosquito specimens (20 spp.) and 424 insect predators (23 spp.) were collected from the rice agroecosystem, mostly from the Central region, followed by the Northeast, the North and the South and were inhabiting rice fields, wetlands and ditches. In China, 928 mosquitoes (15 spp.) and 149 insect predators (16 spp.) were collected from rice fields along the Weishan Lake in Shandong province. Specimens were classified in the orders Diptera, Coleoptera, Odonata and Hemiptera. Using wsp, ftsZ, 16S rRNA and groE gene amplifications, Wolbachia were detected in 12 mosquito spp. and 6 predator spp. from Thailand and 11 mosquito spp. and 5 predator spp. from China. The relative Wolbachia densities of these species were determined using quantitative real-time PCR. The mosquito, Aedes albopictus, and the predator, Agriocnemis femina, had the highest bacterial densities. These results imply that Wolbachia of supergroup B are distributed throughout these insects, probably via horizontal transmission in rice agroecosystems.

  12. Wolbachia Infection and Resource Competition Effects on Immature Aedes albopictus (Diptera: Culicidae)

    PubMed Central

    Gavotte, Laurent; Mercer, David R.; Vandyke, Rhonda; Mains, James W.; Dobson, Stephen L.

    2009-01-01

    Wolbachia pipientis Hertig and Wolbach (Rickettsiales: Rickettsiaceae) are intracellular α-proteobacteria that occur naturally in Aedes albopictus (Skuse) (Diptera: Culicidae) and numerous other invertebrates. These endosymbionts can invade host populations by manipulating host reproduction. Wolbachia infections have been shown to impart both costs and benefits to hosts in terms of development, survival, and fecundity. Here, we monitor intraspecific competition among independent cohorts of infected or uninfected larvae. Levels of competition are manipulated by varying initial larval densities and food levels. Although larval density is observed to have major impacts on immature survivorship, sex ratio of eclosing adults, and developmental rates, the Wolbachia infection status had minimal impact on male immatures and no effect on immature females under these experimental conditions. Female and male immatures were observed to respond differently to competitive pressure, with the functional relationships of females and males consistent with scramble and contest competition, respectively. The results are discussed in relation to the evolution of naturally occurring Wolbachia infections in Ae. albopictus (i.e., natural population replacement events) and public health strategies that propose the manipulation of Wolbachia infections in Ae. albopictus populations. PMID:19496412

  13. Birth of a W sex chromosome by horizontal transfer of Wolbachia bacterial symbiont genome.

    PubMed

    Leclercq, Sébastien; Thézé, Julien; Chebbi, Mohamed Amine; Giraud, Isabelle; Moumen, Bouziane; Ernenwein, Lise; Grève, Pierre; Gilbert, Clément; Cordaux, Richard

    2016-12-27

    Sex determination is a fundamental developmental pathway governing male and female differentiation, with profound implications for morphology, reproductive strategies, and behavior. In animals, sex differences between males and females are generally determined by genetic factors carried by sex chromosomes. Sex chromosomes are remarkably variable in origin and can differ even between closely related species, indicating that transitions occur frequently and independently in different groups of organisms. The evolutionary causes underlying sex chromosome turnover are poorly understood, however. Here we provide evidence indicating that Wolbachia bacterial endosymbionts triggered the evolution of new sex chromosomes in the common pillbug Armadillidium vulgare We identified a 3-Mb insert of a feminizing Wolbachia genome that was recently transferred into the pillbug nuclear genome. The Wolbachia insert shows perfect linkage to the female sex, occurs in a male genetic background (i.e., lacking the ancestral W female sex chromosome), and is hemizygous. Our results support the conclusion that the Wolbachia insert is now acting as a female sex-determining region in pillbugs, and that the chromosome carrying the insert is a new W sex chromosome. Thus, bacteria-to-animal horizontal genome transfer represents a remarkable mechanism underpinning the birth of sex chromosomes. We conclude that sex ratio distorters, such as Wolbachia endosymbionts, can be powerful agents of evolutionary transitions in sex determination systems in animals.

  14. Birth of a W sex chromosome by horizontal transfer of Wolbachia bacterial symbiont genome

    PubMed Central

    Leclercq, Sébastien; Thézé, Julien; Chebbi, Mohamed Amine; Giraud, Isabelle; Moumen, Bouziane; Ernenwein, Lise; Grève, Pierre; Cordaux, Richard

    2016-01-01

    Sex determination is a fundamental developmental pathway governing male and female differentiation, with profound implications for morphology, reproductive strategies, and behavior. In animals, sex differences between males and females are generally determined by genetic factors carried by sex chromosomes. Sex chromosomes are remarkably variable in origin and can differ even between closely related species, indicating that transitions occur frequently and independently in different groups of organisms. The evolutionary causes underlying sex chromosome turnover are poorly understood, however. Here we provide evidence indicating that Wolbachia bacterial endosymbionts triggered the evolution of new sex chromosomes in the common pillbug Armadillidium vulgare. We identified a 3-Mb insert of a feminizing Wolbachia genome that was recently transferred into the pillbug nuclear genome. The Wolbachia insert shows perfect linkage to the female sex, occurs in a male genetic background (i.e., lacking the ancestral W female sex chromosome), and is hemizygous. Our results support the conclusion that the Wolbachia insert is now acting as a female sex-determining region in pillbugs, and that the chromosome carrying the insert is a new W sex chromosome. Thus, bacteria-to-animal horizontal genome transfer represents a remarkable mechanism underpinning the birth of sex chromosomes. We conclude that sex ratio distorters, such as Wolbachia endosymbionts, can be powerful agents of evolutionary transitions in sex determination systems in animals. PMID:27930295

  15. Wolbachia Infections in Aedes aegypti Differ Markedly in Their Response to Cyclical Heat Stress

    PubMed Central

    Wiwatanaratanabutr, Itsanun; White, Vanessa L.; Hoffmann, Ary A.

    2017-01-01

    Aedes aegypti mosquitoes infected with Wolbachia bacteria are currently being released for arbovirus suppression around the world. Their potential to invade populations and persist will depend on interactions with environmental conditions, particularly as larvae are often exposed to fluctuating and extreme temperatures in the field. We reared Ae. aegypti larvae infected with different types of Wolbachia (wMel, wAlbB and wMelPop-CLA) under diurnal cyclical temperatures. Rearing wMel and wMelPop-CLA-infected larvae at 26–37°C reduced the expression of cytoplasmic incompatibility, a reproductive manipulation induced by Wolbachia. We also observed a sharp reduction in the density of Wolbachia in adults. Furthermore, the wMel and wMelPop-CLA infections were not transmitted to the next generation when mosquitoes were exposed to 26–37°C across all life stages. In contrast, the wAlbB infection was maintained at a high density, exhibited complete cytoplasmic incompatibility, and was transmitted from mother to offspring with a high fidelity under this temperature cycle. These findings have implications for the potential success of Wolbachia interventions across different environments and highlight the importance of temperature control in rearing. PMID:28056065

  16. Reproductive compensation favours male-killing Wolbachia in a live-bearing host

    PubMed Central

    Koop, Julie L.; Zeh, David W.; Bonilla, Melvin M.; Zeh, Jeanne A.

    2009-01-01

    Wolbachia are maternally inherited, cellular endosymbionts that can enhance their fitness by biasing host sex ratio in favour of females. Male killing (MK) is an extreme form of sex-ratio manipulation that is selectively advantageous if the self-sacrifice of Wolbachia in males increases transmission through females. In live-bearing hosts, females typically produce more embryos than can be carried to term, and reproductive compensation through maternal resource reallocation from dead males to female embryos could increase the number of daughters born to infected females. Here, we report a new strain of MK Wolbachia (wCsc2) in the pseudoscorpion, Cordylochernes scorpioides, and present the first empirical evidence that reproductive compensation favours the killing of males in a viviparous host. Females infected with the wCsc2 strain produced 26 per cent more and significantly larger daughters than tetracycline-cured females. In contrast to the previously described wCsc1 MK Wolbachia strain in C. scorpioides, wCsc2 infection was not accompanied by an increase in the rate of spontaneous brood abortion. Characterization of the wCsc1 and wCsc2 strains by multi-locus sequence typing and by Wolbachia surface protein (wsp) gene sequencing indicates that the marked divergence between these two MK strains in their impact on host reproductive success, and hence in their potential to spread, has occurred in association with homologous recombination in the wsp gene. PMID:19710065

  17. Wolbachia restricts insect-specific flavivirus infection in Aedes aegypti cells

    PubMed Central

    Sreenu, Vatipally B.; Mottram, Timothy; McFarlane, Melanie

    2016-01-01

    Mosquito-borne viruses are known to cause disease in humans and livestock and are often difficult to control due to the lack of specific antivirals and vaccines. The Wolbachia endosymbiont has been widely studied for its ability to restrict positive-strand RNA virus infection in mosquitoes, although little is known about the precise antiviral mechanism. In recent years, a variety of insect-specific viruses have been discovered in mosquitoes and an interaction with mosquito-borne viruses has been reported for some of them; however, nothing is known about the effect of Wolbachia on insect-specific virus infection in mosquitoes. Here, we show that transinfection of the Drosophila-derived wMelPop Wolbachia strain into Aedes aegypti-derived cells resulted in inhibition and even clearance of the persistent cell-fusing agent flavivirus infection in these cells. This broadens the antiviral activity of Wolbachia from acute infections to persistent infections and from arboviruses to mosquito-specific viruses. In contrast, no effect on the Phasi Charoen-like bunyavirus persistent infection in these cells was observed, suggesting a difference in Wolbachia inhibition between positive- and negative-strand RNA viruses. PMID:27692043

  18. Wolbachia restricts insect-specific flavivirus infection in Aedes aegypti cells.

    PubMed

    Schnettler, Esther; Sreenu, Vatipally B; Mottram, Timothy; McFarlane, Melanie

    2016-11-01

    Mosquito-borne viruses are known to cause disease in humans and livestock and are often difficult to control due to the lack of specific antivirals and vaccines. The Wolbachia endosymbiont has been widely studied for its ability to restrict positive-strand RNA virus infection in mosquitoes, although little is known about the precise antiviral mechanism. In recent years, a variety of insect-specific viruses have been discovered in mosquitoes and an interaction with mosquito-borne viruses has been reported for some of them; however, nothing is known about the effect of Wolbachia on insect-specific virus infection in mosquitoes. Here, we show that transinfection of the Drosophila-derived wMelPop Wolbachia strain into Aedes aegypti-derived cells resulted in inhibition and even clearance of the persistent cell-fusing agent flavivirus infection in these cells. This broadens the antiviral activity of Wolbachia from acute infections to persistent infections and from arboviruses to mosquito-specific viruses. In contrast, no effect on the Phasi Charoen-like bunyavirus persistent infection in these cells was observed, suggesting a difference in Wolbachia inhibition between positive- and negative-strand RNA viruses.

  19. Wolbachia in European Populations of the Invasive Pest Drosophila suzukii: Regional Variation in Infection Frequencies

    PubMed Central

    Gibert, Patricia; Martinez, Julien; Fraimout, Antoine; Jiggins, Francis; Andrieux, Thibault; Siozios, Stefanos; Anfora, Gianfranco; Miller, Wolfgang; Rota-Stabelli, Omar; Mouton, Laurence

    2016-01-01

    The invasive pest Drosophila suzukii is characterized by a specific fresh-fruit targeting behavior and has quickly become a menace for the fruit economy of newly infested North American and European regions. D. suzukii carries a strain of the endosymbiotic bacterium Wolbachia, named wSuz, which has a low infection frequency and no reproductive manipulation capabilities in American populations of D. suzukii. To further understand the nature of wSuz biology and assess its utility as a tool for controlling this pest’s populations, we investigated the prevalence of Wolbachia in 23 European D. suzukii populations, and compared our results with those available in American populations. Our data showed a highly variable infection frequency with a mean prevalence of 46%, which is significantly higher than the 17% found in American populations. Based on Multilocus Sequence Typing analysis, a single wSuz strain was diagnosed in all European populations of D. suzukii. In agreement with American data, we found no evidence of cytoplasmic incompatibility induced by wSuz. These findings raise two questions: a) why Wolbachia is maintained in field populations of D. suzukii and b) what are the selective forces responsible for the variation in prevalence within populations, particularly between European and American continents? Our results provide new insights into the D. suzukii-Wolbachia association and highlight regional variations that await further investigation and that should be taken into account for using Wolbachia-based pest management programs. PMID:26809119

  20. From Parasite to Mutualist: Rapid Evolution of Wolbachia in Natural Populations of Drosophila

    PubMed Central

    Weeks, Andrew R; Turelli, Michael; Harcombe, William R; Reynolds, K. Tracy; Hoffmann, Ary A

    2007-01-01

    Wolbachia are maternally inherited bacteria that commonly spread through host populations by causing cytoplasmic incompatibility, often expressed as reduced egg hatch when uninfected females mate with infected males. Infected females are frequently less fecund as a consequence of Wolbachia infection. However, theory predicts that because of maternal transmission, these “parasites” will tend to evolve towards a more mutualistic association with their hosts. Drosophila simulans in California provided the classic case of a Wolbachia infection spreading in nature. Cytoplasmic incompatibility allowed the infection to spread through individual populations within a few years and from southern to northern California (more than 700 km) within a decade, despite reducing the fecundity of infected females by 15%–20% under laboratory conditions. Here we show that the Wolbachia in California D. simulans have changed over the last 20 y so that infected females now exhibit an average 10% fecundity advantage over uninfected females in the laboratory. Our data suggest smaller but qualitatively similar changes in relative fecundity in nature and demonstrate that fecundity-increasing Wolbachia variants are currently polymorphic in natural populations. PMID:17439303

  1. The symbiotic role of Wolbachia in Onchocercidae and its impact on filariasis.

    PubMed

    Bouchery, T; Lefoulon, E; Karadjian, G; Nieguitsila, A; Martin, C

    2013-02-01

    Symbiotic associations between eukaryotes and microorganisms are frequently observed in nature, and range along the continuum between parasitism and mutualism. The genus Wolbachia contains well-known intracellular bacteria of arthropods that induce several reproductive phenotypes that benefit the transmission of the bacteria. Interestingly, Wolbachia bacteria have been found in the Onchocercidae, a family of filarial nematodes, including species that cause human filarial diseases, e.g. lymphatic filariasis and onchocerciasis. The endosymbiont is thought to be mutualistic in the Onchocercidae, and to provide essential metabolites to the filariae. Currently, Wolbachia bacteria are targets of antibiotic therapy with tetracyclines, which have profound effects on the development, viability and fertility of filarial parasites. This overview article presents the Onchocercidae and Wolbachia, and then discusses the origin and the nature of the symbiosis. It highlights the contribution of Wolbachia to the survival of the filariae and to the development of pathology. Finally, the infection control implications for filariases are debated. Potential directions for future research are also discussed.

  2. Successful establishment of Wolbachia in Aedes populations to suppress dengue transmission.

    PubMed

    Hoffmann, A A; Montgomery, B L; Popovici, J; Iturbe-Ormaetxe, I; Johnson, P H; Muzzi, F; Greenfield, M; Durkan, M; Leong, Y S; Dong, Y; Cook, H; Axford, J; Callahan, A G; Kenny, N; Omodei, C; McGraw, E A; Ryan, P A; Ritchie, S A; Turelli, M; O'Neill, S L

    2011-08-24

    Genetic manipulations of insect populations for pest control have been advocated for some time, but there are few cases where manipulated individuals have been released in the field and no cases where they have successfully invaded target populations. Population transformation using the intracellular bacterium Wolbachia is particularly attractive because this maternally-inherited agent provides a powerful mechanism to invade natural populations through cytoplasmic incompatibility. When Wolbachia are introduced into mosquitoes, they interfere with pathogen transmission and influence key life history traits such as lifespan. Here we describe how the wMel Wolbachia infection, introduced into the dengue vector Aedes aegypti from Drosophila melanogaster, successfully invaded two natural A. aegypti populations in Australia, reaching near-fixation in a few months following releases of wMel-infected A. aegypti adults. Models with plausible parameter values indicate that Wolbachia-infected mosquitoes suffered relatively small fitness costs, leading to an unstable equilibrium frequency <30% that must be exceeded for invasion. These findings demonstrate that Wolbachia-based strategies can be deployed as a practical approach to dengue suppression with potential for area-wide implementation.

  3. Comparative analysis of Wolbachia surface protein in D. melanoagster, A. tabida and B. malayi

    PubMed Central

    Uday, Jayaramaiah; Puttaraju, Hosagavi Puttegowda

    2012-01-01

    Wolbachia surface protein (WSP) is an eight beta-barrel transmembrane structure which participates in host immune response, cell proliferation, pathogenicity and controlled cell death program. The protein has four extracellular loops containing hyper variable regions separated by conserved regions. The WSP structure is homologous to Neisseria surface protein (Nsp A) which has about 34% similarity including antigenic variation and hydrophilicity. Recombination has a large impact on diversity of this protein including positive selection which is major constraint on protein evolution. The molecular mechanism through which Wolbachia induces various reproductive anomalies is unclear; a key feature observed for such anomalies might be because of Wolbachia undergoing extensive recombination. In Wolbachia, increased recombination is observed in ankyrin proteins, surface proteins and in some hypothetical proteins. Genetic divergence is extensive in the WSP gene, WSP is known to be a chimeric protein involved in host-symbiont interactions. Here we predicted the structural and functional variations in WSP sequences of Wolbachia present in D. melanogaster, A. tabida and in B. malayi. PMID:23055615

  4. Detection of Low-Level Cardinium and Wolbachia Infections in Culicoides

    PubMed Central

    Mee, Peter T.; Weeks, Andrew R.; Walker, Peter J.; Hoffmann, Ary A.

    2015-01-01

    Bacterial endosymbionts have been identified as potentially useful biological control agents for a range of invertebrate vectors of disease. Previous studies of Culicoides (Diptera: Ceratopogonidae) species using conventional PCR assays have provided evidence of Wolbachia (1/33) and Cardinium (8/33) infections. Here, we screened 20 species of Culicoides for Wolbachia and Cardinium, utilizing a combination of conventional PCR and more sensitive quantitative PCR (qPCR) assays. Low levels of Cardinium DNA were detected in females of all but one of the Culicoides species screened, and low levels of Wolbachia were detected in females of 9 of the 20 Culicoides species. Sequence analysis based on partial 16S rRNA gene and gyrB sequences identified “Candidatus Cardinium hertigii” from group C, which has previously been identified in Culicoides from Japan, Israel, and the United Kingdom. Wolbachia strains detected in this study showed 98 to 99% sequence identity to Wolbachia previously detected from Culicoides based on the 16S rRNA gene, whereas a strain with a novel wsp sequence was identified in Culicoides narrabeenensis. Cardinium isolates grouped to geographical regions independent of the host Culicoides species, suggesting possible geographical barriers to Cardinium movement. Screening also identified Asaia bacteria in Culicoides. These findings point to a diversity of low-level endosymbiont infections in Culicoides, providing candidates for further characterization and highlighting the widespread occurrence of these endosymbionts in this insect group. PMID:26150447

  5. Wolbachia in European Populations of the Invasive Pest Drosophila suzukii: Regional Variation in Infection Frequencies.

    PubMed

    Cattel, Julien; Kaur, Rupinder; Gibert, Patricia; Martinez, Julien; Fraimout, Antoine; Jiggins, Francis; Andrieux, Thibault; Siozios, Stefanos; Anfora, Gianfranco; Miller, Wolfgang; Rota-Stabelli, Omar; Mouton, Laurence

    2016-01-01

    The invasive pest Drosophila suzukii is characterized by a specific fresh-fruit targeting behavior and has quickly become a menace for the fruit economy of newly infested North American and European regions. D. suzukii carries a strain of the endosymbiotic bacterium Wolbachia, named wSuz, which has a low infection frequency and no reproductive manipulation capabilities in American populations of D. suzukii. To further understand the nature of wSuz biology and assess its utility as a tool for controlling this pest's populations, we investigated the prevalence of Wolbachia in 23 European D. suzukii populations, and compared our results with those available in American populations. Our data showed a highly variable infection frequency with a mean prevalence of 46%, which is significantly higher than the 17% found in American populations. Based on Multilocus Sequence Typing analysis, a single wSuz strain was diagnosed in all European populations of D. suzukii. In agreement with American data, we found no evidence of cytoplasmic incompatibility induced by wSuz. These findings raise two questions: a) why Wolbachia is maintained in field populations of D. suzukii and b) what are the selective forces responsible for the variation in prevalence within populations, particularly between European and American continents? Our results provide new insights into the D. suzukii-Wolbachia association and highlight regional variations that await further investigation and that should be taken into account for using Wolbachia-based pest management programs.

  6. Wolbachia Infections in Aedes aegypti Differ Markedly in Their Response to Cyclical Heat Stress.

    PubMed

    Ross, Perran A; Wiwatanaratanabutr, Itsanun; Axford, Jason K; White, Vanessa L; Endersby-Harshman, Nancy M; Hoffmann, Ary A

    2017-01-01

    Aedes aegypti mosquitoes infected with Wolbachia bacteria are currently being released for arbovirus suppression around the world. Their potential to invade populations and persist will depend on interactions with environmental conditions, particularly as larvae are often exposed to fluctuating and extreme temperatures in the field. We reared Ae. aegypti larvae infected with different types of Wolbachia (wMel, wAlbB and wMelPop-CLA) under diurnal cyclical temperatures. Rearing wMel and wMelPop-CLA-infected larvae at 26-37°C reduced the expression of cytoplasmic incompatibility, a reproductive manipulation induced by Wolbachia. We also observed a sharp reduction in the density of Wolbachia in adults. Furthermore, the wMel and wMelPop-CLA infections were not transmitted to the next generation when mosquitoes were exposed to 26-37°C across all life stages. In contrast, the wAlbB infection was maintained at a high density, exhibited complete cytoplasmic incompatibility, and was transmitted from mother to offspring with a high fidelity under this temperature cycle. These findings have implications for the potential success of Wolbachia interventions across different environments and highlight the importance of temperature control in rearing.

  7. Effects of Larval Nutrition on Wolbachia-Based Dengue Virus Interference in Aedes aegypti (Diptera: Culicidae).

    PubMed

    Kho, Elise A; Hugo, Leon E; Lu, Guangjin; Smith, David D; Kay, Brian H

    2016-07-01

    In order to assess the broad-scale applicability of field releases of