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on the evolution of cytoplasmic incompatibility in haplodiploid species.the most enigmatic sexual manipulation by wolbachia endosymbionts is cytoplasmic incompatibility (ci): infected males are reproductively incompatible with uninfected females. in this paper, we extend the theory on population dynamics and evolution of ci, with emphasis on haplodiploid species. first, we focus on the problem of the threshold to invasion of the wolbachia infection in a population. simulations of the dynamics of infection in small populations show that it does not suffice to assume ...200212144012
searching for wolbachia (rickettsiales: rickettsiaceae) in mosquitoes (diptera: culicidae): large polymerase chain reaction survey and new identifications.bacteria of the genus wolbachia constitute a group of intracellular and maternally inherited micro-organisms that are widespread in arthropods, inducing several reproductive disorders such as cytoplasmic incompatibility in their hosts. considering relevant biological implications related to the presence of wolbachia in several insect orders, for example its potential role as mechanism for rapid speciation and as vehicle to drive genetic markers in wild populations of vectors of medical and veter ...200212144285
recent changes in phenotype and patterns of host specialization in wolbachia bacteria.wolbachia are a genus of bacterial symbionts that are known to manipulate the reproduction of their arthropod hosts, both by distorting the host sex ratio and by inducing cytoplasmic incompatibility. previous work has suggested that some wolbachia clades specialize in particular host taxa, but others are diverse. furthermore, the frequency with which related strains change in phenotype is unknown. we have examined these issues for wolbachia bacteria from acraea butterflies, where different inter ...200212144650
internal spatiotemporal population dynamics of infection with three wolbachia strains in the adzuki bean beetle, callosobruchus chinensis (coleoptera: bruchidae).the adzuki bean beetle, callosobruchus chinensis, is infected with three distinct lineages of endosymbiotic bacteria belonging to the genus wolbachia, which were designated wbrucon, wbruori, and wbruaus. in an attempt to understand the mechanisms underlying the infection with these three organisms, the spatiotemporal infection dynamics of the three wolbachia strains was investigated in detail by using a quantitative pcr technique. during the development of c. chinensis, the wbrucon, wbruori, and ...200212147509
feminizing wolbachia in an insect, ostrinia furnacalis (lepidoptera: crambidae).wolbachia, which forms a group of maternally inherited bacteria in arthropods, often cause reproduction alterations in their hosts, such as cytoplasmic incompatibility, parthenogenesis, male-killing, hybrid breakdown and feminization. to date, wolbachia-induced feminization has been reported only in isopods. here we report that a wolbachia strain feminizes an insect host, ostrinia furnacalis. among 79 wild females of o. furnacalis examined, wolbachia infection was detected in 13 females. twelve ...200212180086
the rate of recombination in wolbachia bacteria. 200212200493
within- and between-population variation for wolbachia-induced reproductive incompatibility in a haplodiploid mite.wolbachia pipientis is a bacterium that induces cytoplasmic incompatibility (ci), the phenomenon in which infected males are reproductively incompatible with uninfected females. ci spreads in a population of hosts because it reduces the fitness of uninfected females relative to infected females. ci encompasses two steps: modification (mod) of sperm of infected males and rescuing (resc) of these chromosomes by wolbachia in the egg. infections associated with ci have mod+ resa+ phenotypes. however ...200212206235
molecular phylogenetic analysis of onchocerca lupi and its wolbachia endosymbiont.the morphology of onchocerca lupi, responsible for canine ocular onchocercosis, is unique within the genus. earlier analyses of the 5s ribosomal rna gene spacer region sequence of the parasite and the 16s ribosomal rna gene sequence of its wolbachia endosymbiotic bacteria (rickettsiales) supported the morphological and biological arguments that o. lupi is a distinct species. however, the exact phylogenetic position of o. lupi and its endosymbiont could not be unambiguously determined. herein we ...200212208043
the filarial endosymbiont wolbachia sp. is absent from setaria equina.wolbachia sp. was first reported in filarial nematodes over 25 yr ago. today, much research is focused on the role of these bacteria in filarial worm biology. the filarial symbionts are closely related to arthropod symbionts, which are known to modify host reproduction and biology through various mechanisms. similarly, it has been suggested that wolbachia sp. is essential for long-term survival and reproduction of filariae. we report that wolbachia sp. 16s rdna was not found in the equine filari ...200212537121
interspecific transfer of wolbachia between two lepidopteran insects expressing cytoplasmic incompatibility: a wolbachia variant naturally infecting cadra cautella causes male killing in ephestia kuehniella.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 ...200212454075
maternal transmission efficiency of wolbachia superinfections in aedes albopictus populations in thailand.we examined the transmission efficiency of 2 strains of wolbachia bacteria that cause cytoplasmic incompatibility in field populations of aedes albopictus by polymerase chain reaction assay. we found mainland and island populations throughout thailand to be superinfected with group a and b bacteria. of 320 wolbachia-positive adult mosquitoes, 97.5% were infected with both groups. single infected individuals of each wolbachia group were encountered in nearly equal numbers. we screened 550 offspri ...200212135258
wolbachia infections and superinfections in cytoplasmically incompatible populations of the european cherry fruit fly rhagoletis cerasi (diptera, tephritidae).wolbachia is an obligately intracellular, maternally inherited bacterium which has been detected in many arthropods. wolbachia infections disperse in host populations by mechanisms such as cytoplasmic incompatibility (ci). ci leads to embryonic mortality which occurs when infected males mate with uninfected females or females with a different wolbachia strain. populations of the european cherry fruit fly rhagoletis cerasi (diptera, tephritidae) were found to be infected by two different wolbachi ...200212406252
cloning and sequencing of wsp encoding gene fragments reveals a diversity of co-infecting wolbachia strains in acromyrmex leafcutter ants.by sequencing part of the wsp gene of a series of clones, we detected an unusually high diversity of nine wolbachia strains in queens of three species of leafcutter ants. up to four strains co-occurred in a single ant. most strains occurred in two clusters (inva and invb), but the social parasite acromyrmex insinuator hosted two additional infections. the multiple wolbachia strains may influence the expression of reproductive conflicts in leafcutter ants, but the expected turnover of infections ...200312470942
host-symbiont conflicts: positive selection on an outer membrane protein of parasitic but not mutualistic rickettsiaceae.the rickettsiaceae is a family of intracellular bacterial symbionts that includes both vertically transmitted parasites that spread by manipulating the reproduction of their host (wolbachia in arthropods) and horizontally transmitted parasites (represented by cowdria ruminantium), and mutualists (wolbachia pipientis in nematode worms). we have investigated the nature of natural selection acting on an outer membrane protein, the wsp gene in wolbachia and its homologue map1 in cowdria, thought lik ...200212140246
two novel strains of wolbachia coexisting in both species of mulberry leafhoppers.wolbachia is an intracellular symbiont that causes reproductive disorders in many insects. its presence in the leafhoppers hishimonoides sellatiformis and hishimonus sellatus, vectors of mulberry dwarf-phytoplasma, was confirmed by the pcr analysis of 16s rdna, ftsz and wsp. sequencing of cloned pcr products revealed that two wolbachia strains coexist in both leafhoppers. the phylogenetic analysis of wsp revealed that these strains belong in novel positions in the b-group of wolbachia. these str ...200212421415
how can sex ratio distorters reach extreme prevalences? male-killing wolbachia are not suppressed and have near-perfect vertical transmission efficiency in acraea encedon.maternally transmitted bacteria that kill male hosts early in their development are found in many insects. these parasites typically infect 1-30% of wild females, but in a few species of insects, prevalences exceed 95%. we investigated one such case in the butterfly acraea encedon, which is infected with a male-killing wolbachia bacterium. we measured three key parameters that affect the prevalence of the parasite: transmission efficiency, rate of survival of infected males, and the direct cost ...200212487358
diploidy restoration in wolbachia-infected muscidifurax uniraptor (hymenoptera: pteromalidae).thelytokous reproduction, where females produce diploid female offspring without fertilization, can be found in many insects. in some hymenoptera species, thelytoky is induced by wolbachia, a group of cytoplasmically inherited bacteria. we compare and contrast early embryonic development in the thelytokous parthenogenetic species muscidifurax uniraptor with the development of unfertilized eggs of the closely related arrhenotokous species, muscidifurax raptorellus. in the wolbachia-infected paras ...200212507486
immunoglobulin g antibodies against the endosymbionts of filarial nematodes (wolbachia) in patients with pulmonary dirofilariasis.the dog parasite dirofilaria immitis can infect humans. patients with pulmonary dirofilariasis were tested for immunoglobulin g (igg) antibodies against the surface protein of wolbachia, the bacterial endosymbiont of d. immitis. these patients showed significantly higher igg titers than healthy individuals from areas in which d. immitis was endemic as well as areas in which it was not endemic. titration of anti-wolbachia surface protein igg could become useful for diagnostic applications.200312522059
characterization of non-cytoplasmic incompatibility inducing wolbachia in two continental african populations of drosophila simulans.wolbachia is an endocellular bacterium infecting arthropods and nematodes. in arthropods, it invades host populations through various mechanisms, affecting host reproduction, the most common of which being cytoplasmic incompatibility (ci). ci is an embryonic mortality occurring when infected males mate with uninfected females or females infected by a different wolbachia strain. this phenomenon is observed in drosophila simulans, an intensively studied wolbachia host, harbouring at least five dis ...200312522425
superinfection of laodelphax striatellus with wolbachia from drosophila simulans.wolbachia are maternally inherited, intracellular alpha-proteobacteria that infect a wide range of arthropods. they manipulate the reproduction of hosts to facilitate their spread into host populations, through ways such as cytoplasmic incompatibility (ci), parthenogenesis, feminization and male killing. the influence of wolbachia infection on host populations has attracted considerable interest in their possible role in speciation and as a potential agent of biological control. in this study, w ...200312522428
male age, host effects and the weak expression or non-expression of cytoplasmic incompatibility in drosophila strains infected by maternally transmitted wolbachia.in drosophila melanogaster, the maternally inherited endocellular microbe wolbachia causes cytoplasmic incompatibility (ci) in crosses between infected males and uninfected females. ci results in a reduction in the number of eggs that hatch. the level of ci expression in this species has been reported as varying from partial (a few eggs fail to hatch) to nonexistent (all eggs hatch). we show that male age in this host species has a large impact on the level of ci exhibited and explains much of t ...200212534211
madness. 200212219740
the distribution of wolbachia in fig wasps: correlations with host phylogeny, ecology and population structure.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 ...200212427319
the evolution of alternative genetic systems in insects.there are three major classes of insect genetic systems: those with diploid males (diplodiploidy), those with effectively haploid males (haplodiploidy), and those without males (thelytoky). mixed systems, involving cyclic or facultative switching between thelytoky and either of the other systems, also occur. i present a classification of the genetic systems of insects and estimate the number of evolutionary transitions between them that have occurred. obligate thelytoky has arisen from each of t ...200312221039
immunomodulatory properties of cystatins.cystatins are natural tight-binding reversible inhibitors of cysteine proteases. because these cysteine proteases exist in all living organisms and because they are involved in various biological and pathological processes, the control of these protease functions by cystatins is of cardinal importance. cystatins are found in mammals but cystatin-like molecules are also present in mammals and parasites. in the immune system, cystatins modulate cathepsin activities and antigen presentation. they a ...200212440772
influence of antibiotics on the offspring production of the wolbachia-infected parthenogenetic parasitoid encarsia formosa.three different concentrations of the antibiotic tetracycline in honey were tested for their influence on the offspring production and longevity of the parasitoid wasp encarsia formosa. several earlier publications did not provide a conclusive answer on the effect that the wolbachia have on these wasps. the results of our experiments show that at high tetracycline hydrochloride concentrations in honey (50mg/ml) the antibiotic is toxic to the females, all females died within three days after the ...200212234541
brugia malayi: effects of antibacterial agents on larval viability and development in vitro.recent studies have suggested that intracellular wolbachia bacteria are necessary for reproduction and survival of adult filarial worms. we now report results of in vitro studies of effects of antibacterial antibiotics (tetracycline, rifampicin, chloramphenicol, azithromycin, and doxycycline) on brugia malayi infective larvae (l3) motility and molting. all of the antibiotics tested except chloramphenicol decreased l3 motility by 50% or more at 10 days, with minimal effective concentrations (mecs ...200212243742
diversity and geographic distribution of secondary endosymbiotic bacteria in natural populations of the pea aphid, acyrthosiphon pisum.in addition to the essential intracellular symbiotic bacterium buchnera, several facultative endosymbiotic bacteria called collectively secondary symbionts (s-symbionts) have been identified from the pea aphid acyrthosiphon pisum. we conducted an extensive and systematic survey of s-symbionts in japanese local populations of a. pisum using a specific pcr detection technique. five s-symbionts of a. pisum, pass, paus, pabs, rickettsia and spiroplasma, and two facultative endosymbionts universally ...200212296954
evolution of wolbachia-induced cytoplasmic incompatibility in drosophila simulans and d. sechellia.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, in ...200212389718
wolbachia interactions that determine drosophila melanogaster survival.we have recently described a mutualistic symbiosis in which wolbachia bacteria were shown to improve the fitness of some drosophila melanogaster stocks. wolbachia did not extend longevity in all drosophila genotypes, even though 16s rdna sequences indicated that our drosophila stocks were infected with the same wolbachia strain. here, we use reciprocal hybrid crosses between two drosophila strains, one that lived longer with wolbachia (z53) and one that did not (z2), to investigate the inheritan ...200212449484
tetracycline treatment and sex-ratio distortion: a role for wolbachia in the moulting of filarial nematodes?filarial nematodes harbour intracellular bacteria of the genus wolbachia. these bacteria are thought to be beneficial to the host nematode. indeed, tetracycline treatments reduce the population of wolbachia in filarial worms and have detrimental effects on the nematode. even though various antibiotic-curing experiments have been performed on filariae, the actual role of wolbachia in the biology of these nematodes is not yet clear. to address this issue, we designed a first experiment on a model ...200212392911
real-time pcr for quantification of the bacterial endosymbionts (wolbachia) of filarial nematodes.filarial nematodes harbour intracellular symbiotic bacteria belonging to the genus wolbachia. wolbachia is thought to play an important role in the biology of the nematode. moreover, wolbachia appears to be involved in the immunopathogenesis of filariasis and in the onset of the side-effects of antifilarial therapy. investigations in these research areas require reliable methods to quantify wolbachia both in nematodes and in vertebrate tissues. to this purpose, we designed a quantitative real-ti ...200112402526
onchocerciasis. 200312543839
gene transfer: gene swapping craze reaches eukaryotes.recent studies have provided evidence for gene transfers from prokaryotes to eukaryotes and between eukaryotes. the mechanisms and frequencies of these transfers remain the subject of speculation, but the findings provide ample reason to seriously consider interspecies gene transfer as an important evolutionary process in eukaryotes.200312546803
wolbachia distribution and cytoplasmic incompatibility during sperm development: the cyst as the basic cellular unit of ci expression.the growth and distribution of the intracellular microbe wolbachia pipientis during spermatogenesis in several different host/symbiont genetic combinations in drosophila melanogaster and drosophila simulans is described. considerable intra- and inter-strain variation in wolbachia density and tissue distribution was observed. wolbachia were found inside spermatocytes and spermatids or within the somatic cyst cells surrounding the germ cells. some strains displayed both tissue distributions. high ...200312559491
space and the persistence of male-killing endosymbionts in insect populations.male-killing bacteria are bacteria that are transmitted vertically through the females of their insect hosts. they can distort the sex ratio of their hosts by killing infected male offspring. in nature, male-killing endosymbionts (male killers) often have a 100% efficient vertical transmission, and multiple male-killing bacteria infecting a single population are observed. we use different model formalisms to study these observations. in mean-field models a male killer with perfect transmission d ...200212573064
th1 response in balb/c mice immunized with dirofilaria immitis soluble antigens: a possible role for wolbachia?the immune response to filarial infection has been shown to be of both the th1 and th2 types. studies aimed at developing immunization strategies against dirofilaria immitis infection in dogs have shown that protection against larval challenge is of the th2 type and that several proteins are recognized by immunized or infected animals. the bacterial endosymbiont wolbachia, harbored by many filarial species including d. immitis, has recently been shown to interact with the host immune system. spe ...200312581590
involvement of toll-like receptor 4 in the embryogenesis of the rodent filaria litomosoides sigmodontis.to examine the role that lipopolysaccharide (lps)-like molecules from the filarial intracellular endobacteria wolbachia might play in the development of filarial infections, a natural infection in the lps-nonresponsive c3h/hej mouse strain was compared to that of the lps-responsive c3h/hen mouse strain. c3h/hen mice have been shown to be susceptible to the rodent filarial nematode litomosoides sigmodontis, with the development of adult worms including females containing mature microfilariae (fir ...200312592564
wolbachia pipientis growth kinetics and susceptibilities to 13 antibiotics determined by immunofluorescence staining and real-time pcr.wolbachia spp. are strict intracellular bacteria that infect a wide range of arthropods and filarial nematodes. filarial nematodes are important causes of human diseases. there is increasing evidence that wolbachia spp. influence important functions in the biology of the hosts, specifically, infertility. preliminary experiments with humans and animals have suggested that antibiotics with activity against wolbachia may help to treat filariasis. in this study, we determined using a real-time quant ...200312709338
immunopathogenesis of onchocerca volvulus keratitis (river blindness): a novel role for endosymbiotic wolbachia bacteria.river blindness is thought to occur as a result of the host response to degenerating microfilariae in the eye. utilizing a murine model of corneal inflammation (keratitis) to investigate the immune and inflammatory responses associated with river blindness, we recently demonstrated an important role for endotoxin-like products from endosymbiotic bacteria and for activation of toll-like receptor 4 (tlr4). these observations have led to a new understanding of the pathogenesis of this disease200312592565
[possible bacterial etiologies for diseases of unknown origin]. 200312717985
on the mechanism of wolbachia-induced cytoplasmic incompatibility: confronting the models with the facts.the endocellular bacterium wolbachia manipulates the reproduction of its arthropod hosts for its own benefit by various means, the most widespread being cytoplasmic incompatibility (ci). to date, the molecular mechanism involved in ci has not been elucidated. we examine here three different ci models described in previous literature, namely, the "lock-and-key", "titration-restitution" and "slow-motion" models. we confront them with the full range of ci patterns discovered so far, including the m ...200312596230
molecular phylogeny of wolbachia endosymbionts in southeast asian mosquitoes (diptera: culicidae) based on wsp gene sequences.wolbachia are maternally inherited intracellular bacteria that infect a wide range of arthropods and nematodes and are associated with various reproductive abnormalities in their hosts. insect-associated wolbachia form a monophyletic clade in the alpha-proteobacteria and recently have been separated into two supergroups (a and b) and 19 groups. our recent polymerase chain reaction (pcr) survey using wsp specific primers indicated that various strains of wolbachia were present in mosquitoes colle ...200312597646
differences in extent of genetic introgression between sympatric culex pipiens and culex quinquefasciatus (diptera: culicidae) in california and south africa.comparisons of five morphological characters, 12 enzyme electrophoresis profiles, and wolbachia pipientis infection rates were used to characterize populations of members of the culex pipiens l. complex in california and south africa. in south africa, male phallosome dv/d ratio, male maxillary palp index, branching of siphonal seta 1a, the enzyme locus mdhp-1, and w. pipientis infection rates proved highly diagnostic for separating culex quinquefasciatus from cx. pipiens phenotypes. in johannesb ...200312597651
wolbachia as a potential tool for suppressing filarial transmission.there is currently a great deal of interest in wolbachia because of their wide distribution in arthropods and filarial nematodes and their striking effects on the biology of their hosts, including a possible role in speciation. they manipulate the reproduction of arthropod hosts through various effects on their hosts' biology, particularly cytoplasmic incompatibility (ci), to increase the proportion of infected individuals in the population, often to the point of fixation. this ability of wolbac ...200212625925
pcr-based detection and identification of the filarial parasite brugia timori from alor island, indonesia.brugia timori is widely distributed on alor island, indonesia, where it causes a high degree of morbidity. the hhai tandem repeat of b. timori was found to be identical to that of b. malayi, for which sensitive pcr-based assays have already been developed. using one of these assays, a single microfilaria (mf) of b. timori, present in a spot of dry blood on filter paper, could be detected. the assay was equally sensitive in the detection of b. timori and b. malayi. when the collected mosquitoes w ...200212625936
in vitro cultivation of wolbachia in insect and mammalian cell lines.wolbachia infecting the small brown planthopper, laodelphax striatellus, were successfully maintained and cultivated in two insect and one mammalian cell lines. the bacteria with the planthopper ovary were introduced into the flasks with the cultures of the cell lines. the wolbachia proliferated in mosquito (aedes albopictus) and lepidopteran (heliothis zea) cell lines and in the mouse cell line, l929. proliferation of wolbachia was confirmed by electron microscopy and quantitative polymerase ch ...200212534342
the pathogenesis of filarial lymphedema: is it the worm or is it the host?our understanding of the pathogenesis of filarial lymphedema, although evolving, is still limited. recurrent bacterial infections play a major role in the progression of lymphedema to elephantiasis, but the host and parasite factors that trigger disease development are not known. field studies in haiti show that lymphedema and host responses to parasite antigens cluster in families, consistent with the hypothesis that host genes influence lymphedema susceptibility. the recent recognition that fi ...200212543723
immunohistochemical/immunogold detection and distribution of the endosymbiont wolbachia of dirofilaria immitis and brugia pahangi using a polyclonal antiserum raised against wsp (wolbachia surface protein).intracellular bacteria in filarial nematodes were described as early as the 1970s, yet it was only with the work on dirofilaria immitis, the agent of canine and feline heartworm disease, that these microorganisms were identified as belonging to wolbachia, a genus known for encompassing bacteria infecting insects and other arthropods. the implications for the presence of intracellular bacteria in filarial nematodes is now the subject of intense research, particularly regarding their role in the i ...200312632152
wolbachia segregation dynamics and levels of cytoplasmic incompatibility in drosophila sechellia.in drosophila sechellia, the endocellular bacterium wolbachia induces cytoplasmic incompatibility (ci): in crosses involving infected males, a partial or complete embryonic mortality occurs unless the female bears the same wolbachia. d. sechellia is known to harbour two wolbachia variants, namely wsh and wsn, closely related to wha and wno, respectively, two strains infecting the populations of d. simulans from the seychelles archipelago and new caledonia. strikingly, the two species show simila ...200312634822
molecular detection of bartonella quintana, b. koehlerae, b. henselae, b. clarridgeiae, rickettsia felis, and wolbachia pipientis in cat fleas, france.the prevalences of bartonella, rickettsia, and wolbachia were investigated in 309 cat fleas from france by polymerase chain reaction (pcr) assay and sequencing with primers derived from the glta gene for rickettsia, the its and pap31 genes for bartonella, and the 16s rrna gene for anaplasmataceae. positive pcr results were confirmed by using the lightcycler and specific primers for the rompb of rickettsia and glta of bartonella. r. felis was detected in 25 fleas (8.1%), w. pipientis, an insect s ...200312643829
cytoplasmic incompatibility and sperm cyst infection in different drosophila-wolbachia associations.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 ...200312807775
reversing wolbachia-based population replacement.genetic manipulation that reduces the competence of a vector population to transmit pathogens would provide a useful tool to complement current control strategies, which are based primarily on the reduction/exclusion of vector populations and the prophylactic/therapeutic treatment of the vertebrate host population. genetic drive is an important component of vector population replacement strategies, facilitating the replacement of natural populations with a genetically modified population. geneti ...200312643996
cloning and characterization of a gene encoding glutathione-regulated potassium-efflux system protein kefkl from the endosymbiont wolbachia.the maternally inherited intracellular symbiont wolbachia is well known for inducing a variety of reproductive and developmental abnormalities in the diverse arthropod hosts it infects. it has been implicated in causing cytoplasmic incompatibility (ci), parthenogenesis, feminization of genetic males and male killing in different hosts. however, the molecular mechanisms by which this fastidious bacterium causes these abnormalities have not yet been determined. in our study, representational diffe ...200212652910
regulation of wolbachia density in the mediterranean flour moth, ephestia kuehniella, and the almond moth, cadra cautella.the mediterranean flour moth, ephestia kuehniella, is infected with a-group wolbachia (wkue), and the almond moth, cadra cautella, is doubly infected with a- and b-group wolbachia, which are designated as wcaua and wcaub, respectively. in both insects, the wolbachia populations increased greatly during embryonic and larval stages. the wolbachia population doubled every 3.6 days on average in e. kuehniella larvae, whereas those of wcaua and wcaub doubled every 2.1 days in c. cautella larvae. the ...200312655178
the cytogenetics of thelytoky in a predominantly asexual parasitoid wasp with covert sex.asexual lineages in the parasitoid wasp lysiphlebus fabarum (hymenoptera: braconidae: aphidiinae) have previously been shown to have occasionally undergone sexual reproduction and recombination with males from related sexual populations. in the present study, the cytogenetic system of asexual females in this species is shown by 4',6-diamidino-2-phenylindole dihydrochloride (dapi) staining to be central fusion automixis. this system has the potential to allow occasional sex and recombination with ...200312669810
genetic conflicts over sex ratio: mite-endosymbiont interactions.nucleocytoplasmic genetic conflicts arise as a result of asymmetric transmission of cytoplasmic and nuclear genes. spread of a cytoplasmic element promoting female-biased sex ratios creates selection on nuclear genes for mechanisms that decrease the bias. here we investigate the conflict over sex ratio between the cytoplasmic bacterium wolbachia and the two-spotted spider mite tetranychus urticae koch. we show that, first, infected females produce significantly more female-biased sex ratios than ...200312675371
high levels of multiple wolbachia infection and recombination in the ant formica exsecta.wolbachia bacteria are intracellular symbionts of many arthropod species. their spread through host populations is promoted by drastic alterations imposed on their hosts' reproductive physiology. in the present study, we analyzed the association between wolbachia strains and host mitochondrial haplotypes in a swiss population of the ant formica exsecta. in this species, female dispersal is extremely limited and the mitochondrial haplotypes are strongly differentiated between and within subpopula ...200312679529
doxycycline as a novel strategy against bancroftian filariasis-depletion of wolbachia endosymbionts from wuchereria bancrofti and stop of microfilaria production.chemotherapy of onchocerciasis by doxycycline, which targets symbiotic wolbachia endobacteria, has been shown to result in a long-term sterility of adult female worms and corresponding absence of microfilariae. it represents an additional chemotherapeutic approach. the aim of this study was to determine whether a similar regimen would also show efficacy against wuchereria bancrofti. ghanaian individuals ( n=93) with lymphatic filariasis and a minimum microfilaremia of 40 microfilariae/ml were in ...200312684759
wolbachia-induced mortality as a mechanism to modulate pathogen transmission by vector arthropods.insecticide resistance and absence of clinical cures or vaccines for many vector-borne diseases has stimulated interest in using genetically modified arthropod vectors for disease control. current transgenic strategies focus on vector susceptibility to pathogen infection, which is an inefficient target for pathogen transmission interference. manipulation of vector survival is theoretically more effective, resulting in larger reductions in the expected number of human infections. a hypothetical m ...200312693838
molecular evidence for novel tick-associated spotted fever group rickettsiae from thailand.ticks are of considerable medical and veterinary importance because they directly harm the host through their feeding action and indirectly through vectoring many bacterial pathogens. despite many ticks being known from thailand, very little is known about the bacteria they may harbor. we report here the results of a survey of tick-associated bacteria in thailand. a total of 334 individuals representing 14 species of ticks in five genera were collected from 10 locations in thailand and were exam ...200312693853
different rates of nucleotide substitutions in wolbachia endosymbionts of arthropods and nematodes: arms race or host shifts?the genus wolbachia encompasses intracellular bacteria found in arthropods and in filarial nematodes. in arthropods, wolbachia is primarily a reproductive parasite and shows relatively frequent horizontal transfer between host species, while in nematodes it appears to be a mutualist and is strictly vertically transmitted. we can expect that different selective pressures are acting on their genomes. here we present an analysis of three wolbachia genes, wsp, ftsz and dnaa. in wsp of arthropod wolb ...200212701381
doxycycline in the treatment of human onchocerciasis: kinetics of wolbachia endobacteria reduction and of inhibition of embryogenesis in female onchocerca worms.recently, experts have warned that mass treatment with ivermectin alone may not interrupt the transmission of onchocerca. hence, additional drugs are needed, such as antibiotics acting on symbiotic endobacteria of the filariae, the causative agents of onchocerciasis. based on animal experiments, human onchocerciasis was treated with doxycycline, and preliminary observations published in 2001 in the lancet showed sterility in female worms by depletion and marked reduction in symbiotic wolbachia e ...200312706439
rna polymerase beta-subunit-based phylogeny of ehrlichia spp., anaplasma spp., neorickettsia spp. and wolbachia pipientis.sequence analysis of rpob, the gene encoding the beta-subunit of rna polymerase, was used in a phylogenetic investigation of nine species from the genera ehrlichia, neorickettsia, wolbachia and anaplasma. the complete nucleotide sequences obtained for anaplasma phagocytophilum (hge agent), ehrlichia chaffeensis, neorickettsia sennetsu, neorickettsia risticii, anaplasma marginale and wolbachia pipientis were amongst the longest rpob sequences in genbank and ranged from 4074 bp for n. sennetsu to ...200312710612
an aspartate aminotransferase of wolbachia endobacteria from onchocerca volvulus is recognized by igg1 antibodies from residents of endemic areas.wolbachia are intracellular alpha-proteobacteria, closely related to rickettsia, that infect various arthropods and filarial parasites. in the present study, the cdna encoding the aspartate aminotransferase (aspat) of wolbachia from the human pathogenic filarial parasite onchocerca volvulus (ov-wolaspat) was identified. at the amino acid level, the identity of the ov-wolaspat was 56% to rickettsia prowazekii aspat and 54% to the aspat of the nitrogen-fixing bacterium sinorhizobium meliloti, but ...200312743802
no evidence of wolbachia endosymbiosis with loa loa and mansonella perstans.endosymbiotic wolbachia bacteria from different filarial species, including major pathogens of humans such as wuchereria bancrofti, brugia malayi and onchocerca volvulus, seem to play an important role in the development, viability and fertility of these worms. wolbachia trigger inflammatory host responses as well as adverse reactions against standard treatment regimens and are therefore under investigation as novel treatment targets. we investigated whether wolbachia are also endosymbiotic in l ...200312748849
male-killing wolbachia and mitochondrial dna: selective sweeps, hybrid introgression and parasite population dynamics.mitochondrial dna (mtdna) sequences are widely used as neutral genetic markers in insects. however, patterns of mtdna variability are confounded by the spread of maternally transmitted parasites, which are genetically linked to the mitochondria. we have investigated these effects in the butterflies acraea encedon (which is host to two strains of male-killing wolbachia bacteria) and a. encedana (which is host to one strain). within a population, the mitochondria are in linkage disequilibrium with ...200312750316
host genotype determines cytoplasmic incompatibility type in the haplodiploid genus nasonia.in haplodiploid species, wolbachia-induced cytoplasmic incompatibility (ci) can be expressed in one of two ways: as a "conversion" of diploid fertilized eggs into haploid males or as embryonic mortality. here we describe ci-type variation within the parasitic wasp genus nasonia and genetically analyze the basis of this variation. we reach four main conclusions: (i) ci is expressed primarily as conversion in n. vitripennis, but as embryonic mortality in the sibling species n. giraulti and n. long ...200312750334
wolbachia infection complexity among insects in the tropical rice-field community.wolbachia are a group of intracellular bacteria that cause reproductive alterations in their arthropod hosts. widely discordant host and wolbachia phylogenies indicate that horizontal transmission of these bacteria among species sometimes occurs. a likely means of horizontal transfer is through the feeding relations of organisms within communities. feeding interactions among insects within the rice-field insect community have been well documented in the past. here, we present the results of a po ...200312753223
antibiotic therapy in murine filariasis (litomosoides sigmodontis): comparative effects of doxycycline and rifampicin on wolbachia and filarial viability.the symbiosis of filarial nematodes and rickettsial wolbachia endobacteria has been exploited as a target for antibiotic therapy of filariasis. depletion of wolbachia after tetracycline treatment results in filarial sterility because of interruption of embryogenesis and inhibits larval development and adult worm viability. the aim of this study was to investigate if antibiotic intervention of balb/c mice infected with the rodent filaria litomosoides sigmodontis with rifampicin or the combination ...200312753632
respiration of a rickettsialike microorganism, wolbachia persica. 196214005862
wolbachia endosymbionts in fleas (siphonaptera).intracellular endosymbionts, wolbachia spp., have been reported in many different orders of insects and in nematodes but not previously in fleas. this is the first conclusive report of wolbachia spp. within members of the siphonaptera. using nested polymerase chain reaction (pcr) targeting of the 16s ribosomal rna gene, we screened for wolbachia spp. in fleas collected from 3 counties in georgia and 1 in new york. the prevalence of wolbachia spp. detected varied among the 6 different species scr ...200312760642
obligatory symbiotic wolbachia endobacteria are absent from loa loa.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 filar ...200312801420
effects of wolbachia on mtdna variation in two fire ant species.wolbachia are endosymbiotic bacteria that infect arthropods. as they are maternally transmitted, the spread of wolbachia variants within host populations may affect host mtdna evolution. we sequenced a portion of the mitochondrial cytochrome oxidase i gene from numerous individuals of two wolbachia-infected fire ant species, solenopsis invicta and s. richteri, to determine how these bacteria influence patterns of mtdna variation. as predicted, there was a strong association between wolbachia str ...200312803629
studies on the cell envelope of wolbachia persica. 196414144721
wolbachia and genetic variability in the birdnest blowfly protocalliphora sialia.wolbachia are widespread cytoplasmically inherited bacteria that induce various reproductive alterations in host arthropods, including cytoplasmic incompatibility (ci), an incompatibility between sperm and egg that typically results in embryonic death. ci has been invoked as a possible mechanism for reproductive isolation and speciation in arthropods, by restricting gene flow and promoting maintenance (and evolution) of genetic divergence between populations. here we investigate patterns of wolb ...200312803636
brugia pahangi and wolbachia: the kinetics of bacteria elimination, worm viability, and host responses following tetracycline treatment.wolbachia spp., first reported from filariae nearly 30 years ago, have been suggested to contribute to the pathogenesis associated with human filarial infection. tetracycline has been used to cure filariae of wolbachia, as a novel means of chemotherapeutic treatment for both ocular and lymphatic filariasis. tetracycline treatment of l4 or adult brugia pahangi in vivo resulted in wolbachia clearance. less tetracycline was required to clear wolbachia when treatment began at the l4 stage, compared ...200312810042
evidence against wolbachia symbiosis in loa loa.background: the majority of filarial nematode species are host to wolbachia bacterial endosymbionts, although a few including acanthocheilonema viteae, onchocerca flexuosa and setaria equina have been shown to be free of infection. comparisons of species with and without symbionts can provide important information on the role of wolbachia symbiosis in the biology of the nematode hosts and the contribution of the bacteria to the development of disease. previous studies by electron microscopy and ...200312816546
the invasion and coexistence of competing wolbachia strains.cytoplasmic incompatibility between arthropods infected with different strains of wolbachia has been proposed as an important mechanism for speciation. however, a basic requirement for this mechanism is the coexistence of different strains in neighbouring populations. here we test whether this required coexistence is possible in a spatial context. continuous-time models for the behaviour of one and two strains of wolbachia within a single well-mixed population demonstrate the allee effect and fo ...200314512953
endosymbiotic bacterium wolbachia pipientis in synanthropic populations of the mosquito culex pipiens pipiens l. (diptera, culicidae). 200312854423
tunga penetrans: molecular identification of wolbachia endobacteria and their recognition by antibodies against proteins of endobacteria from filarial parasites.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 ...200212856318
wolbachia in the inflammatory pathogenesis of human filariasis.filarial nematodes cause some of the most debilitating diseases in tropical medicine. recent studies, however, have implicated the parasites' endosymbiotic wolbachia bacteria, rather than the nematode, as the cause of inflammatory-mediated filarial disease. soluble extracts of a variety of filarial species stimulate innate inflammatory responses, which are absent or reduced when using extracts derived from species either devoid of bacteria, or those cleared of bacteria by antibiotics. characteri ...200312860672
between- and within-host species selection on cytoplasmic incompatibility-inducing wolbachia in haplodiploids.the most common effect of the endosymbiont wolbachia is cytoplasmic incompatibility (ci), a form of postzygotic reproductive isolation that occurs in crosses where the male is infected by at least one wolbachia strain that the female lacks. we revisited two puzzling features of wolbachia biology: how wolbachia can invade a new species and spread among populations, and how the association, once established in a host species, can evolve, with emphasis on the possible process of infection loss. the ...200312683537
evolutionary consequences of wolbachia infections.the past decade has revealed the bacterium wolbachia as the most widespread symbiont of arthropods and nematodes. behind this evolutionary success is an remarkable variety of effects on host biology, ranging from manipulation of reproduction in favor of females to more classical mutualistic interactions. here we discuss the potential of wolbachia for promoting evolutionary changes in its hosts.200312683975
bacterial diversity in worker adults of apis mellifera capensis and apis mellifera scutellata (insecta: hymenoptera) assessed using 16s rrna sequences.high-fidelity pcr of 16s rrna sequences was used to identify bacteria associated with worker adults of the honeybee subspecies apis mellifera capensis and apis mellifera scutellata. an expected approximately 1.5-kb dna band, representing almost the entire length of the 16s rrna gene, was amplified from both subspecies and cloned. ten unique sequences were obtained: one sequence each clustered with bifidobacterium (gram-positive eubacteria), lactobacillus (gram-positive eubacteria), and gluconace ...200314615218
the effects of host age, host nuclear background and temperature on phenotypic effects of the virulent wolbachia strain popcorn in drosophila melanogaster.because of their obligate endosymbiotic nature, wolbachia strains by necessity are defined by their phenotypic effects upon their host. nevertheless, studies on the influence of host background and environmental conditions upon the manifestation of wolbachia effects are relatively uncommon. here we examine the behavior of the overreplicating wolbachia strain popcorn in four different drosophila melanogaster backgrounds at two temperatures. unlike other strains of wolbachia in drosophila, popcorn ...200312871912
evolution 2003 meeting. genetic deficiency blamed on bacteria. 200312881548
analysis of 16s rrna gene sequences of ehrlichia canis, anaplasma platys, and wolbachia species from canine blood in japan.in the present study, three canine blood samples from japan, that were suspected to be ehrlichia positive were examined. after sequencing the 16s rrna genes, each dog was found to be infected either with ehrlichia canis (kagoshima 1), anaplasma platys (okinawa 1), or wolbachia sp. (okinawa 2). phylogenic analysis was performed on these sequences. the nearly entire 16s rrna sequence of kagoshima 1 was found to be most similar to the sequences from oklahoma and venezuela e. canis strains (1 base p ...200312860708
trans-species transfer of wolbachia: microinjection of wolbachia from litomosoides sigmodontis into acanthocheilonema viteae.intracellular bacteria of the genus wolbachia are found in most filarial nematodes, but are lacking in some species like acanthocheilonema viteae. due to their symbiotic nature and their role in the pathology of filarial infections they are considered to be potential targets for intervention against filarial infections in man. infection of a. viteae (a species which does not naturally carry wolbachia) with wolbachia bacteria could allow comparative studies on the effect of the endobacterium on t ...200312866789
sperm chromatin remodelling and wolbachia-induced cytoplasmic incompatibility in drosophila.wolbachia pipientis is an obligate bacterial endosymbiont, which has successfully invaded approximately 20% of all insect species by manipulating their normal developmental patterns. wolbachia-induced phenotypes include parthenogenesis, male killing, and, most notably, cytoplasmic incompatibility. in the future these phenotypes might be useful in controlling or modifying insect populations but this will depend on our understanding of the basic molecular processes underlying insect fertilization ...200312897857
characterization of antibody responses to wolbachia surface protein in humans with lymphatic filariasis.symbiotic wolbachia organisms of filarial nematodes have received much attention as possible chemotherapy targets and disease-causing organisms. in order to further investigate the association between anti-wolbachia immune responses and chronic filarial disease in humans, antibody responses to wolbachia surface protein (wsp) were assayed in serum samples collected from 232 individuals living in leogane, haiti, an area where wuchereria bancrofti infection is endemic, and from 67 north americans w ...200312933853
wolbachia distribution and cytoplasmic incompatibility based on a survey of 42 spider mite species (acari: tetranychidae) in japan.wolbachia are a group of maternally inherited bacteria that infect a wide range of arthropods. wolbachia infections are known to result in the expression of various abnormal reproductive phenotypes, the best known being cytoplasmic incompatibility. the first systematic survey of 42 spider mite species in japan revealed that seven species (16.7%) were infected with wolbachia. wolbachia in the spider mites were grouped into three subgroups in supergroup b by phylogenetic analyses of the wsp gene. ...200312939620
identification of wolbachia--host interacting factors through cytological analysis.manipulation of host reproduction and efficient maternal transmission have facilitated the global spread of wolbachia through millions of insect species. cytological studies of the most common wolbachia-induced phenotype, cytoplasmic incompatibility (ci), demonstrate that wolbachia induce ci by altering host cell cycle timing. cytological analyses also suggest that microtubules and motor proteins may play a role in the maternal and somatic transmission of wolbachia.200312941392
infection of new- and old-world aedes albopictus (diptera: culicidae) by the intracellular parasite wolbachia: implications for host mitochondrial dna evolution.wolbachia are cytoplasmically inherited, endosymbiotic bacteria known to infect a wide variety of arthropods. polymerase chain reaction (pcr) amplification of the wolbachia surface protein (wsp) gene was used to assay the infection of geographically disparate populations of aedes albopictus (skuse) by wolbachia. nine north american, four south american, one hawaiian, and four old world populations of a. albopictus were all doubly infected with both the walba and walbb strains of wolbachia. a 365 ...200312943116
incidence of a new sex-ratio-distorting endosymbiotic bacterium among arthropods.many intracellular micro-organisms are now known to cause reproductive abnormalities and other phenomena in their hosts. the endosymbiont wolbachia is the best known of these reproductive manipulators owing to its extremely high incidence among arthropods and the diverse host effects it has been implicated as causing. however, recent evidence suggests that another intracellular bacterium, a cytophaga-like organism (clo), may also induce several reproductive effects in its hosts. here, we present ...200312964989
variable male potential rate of reproduction: high male mating capacity as an adaptation to parasite-induced excess of females?numerous animals are known to harbour intracytoplasmic symbionts that gain transmission to a new host generation via female eggs and not male sperm. bacteria of the genus wolbachia are a typical example. they infect a large range of arthropod species and manipulate host reproduction in several ways. in terrestrial isopods (woodlice), wolbachia are responsible for converting males into females (feminization (f)) in some species, or for infertility in certain host crosses in other species (cytopla ...200312965021
infection density of wolbachia and level of cytoplasmic incompatibility in the mediterranean flour moth, ephestia kuehniella.wolbachia, a causative agent of various reproductive changes in arthropods, induces cytoplasmic incompatibility (ci) in the mediterranean flour moth, ephestia kuehniella. two strains of e. kuehniella, yokohama and tsuchiura, harbor closely related wolbachia, but the yokohama strain expresses stronger ci than the tsuchiura strain. a transinfected e. kuehniella strain that harbors the wolbachia derived from the almond moth cadra cautella, expresses weak ci at a similar level to the tsuchiura strai ...200313678706
the potential of virulent wolbachia to modulate disease transmission by insects.a virulent strain of wolbachia has recently been identified in drosophila that drastically reduces adult lifespan. it has been proposed that this phenotype might be introduced into insect disease vector populations to reduce pathogen transmission. here we model the requirements for spread of such an agent and the associated reduction in disease transmission. first, a simulation of mosquito population age structure was used to describe the age distribution of mosquitoes transmitting dengue virus. ...200313678709
lipid metabolism of the rickettsialike microorganism wolbachia persica. i. incorporation of long chain fatty acids into phosphatides. 196414118046
lipid metabolism of the rickettsialike microorganism wolbachia persica. ii. studies with labeled nonlipid substrates. 196414118047
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