Publications

linkage disequilibria between mtdna haplotypes and chromosomal arrangements in a natural population of drosophila subobscura.	the association between mtdna haplotypes and chromosomal arrangements in a natural population of drosophila subobscura from calvia (balearic islands, spain) was studied in order to search for linkage disequilibria, in an attempt to explain the populational dynamics of the mtdna haplotypes of this species in nature. the presence of wolbachia was not detected. two main haplotypes (i and ii) were found, as well as a series of less common ones. the tajima d-test seemed to indicate some kind of seaso ...	2002	12136416
genome fragment of wolbachia endosymbiont transferred to x chromosome of host insect.	the adzuki bean beetle, callosobruchus chinensis, is triple-infected with distinct lineages of wolbachia endosymbiont, wbrucon, wbruori, and wbruaus, which were identified by their wsp (wolbachia surface protein) gene sequences. whereas wbrucon and wbruori caused cytoplasmic incompatibility of the host insect, wbruaus did not. although wbrucon and wbruori were easily eliminated by antibiotic treatments, wbruaus persisted over five treated generations and could not be eliminated. the inheritance ...	2002	12386340
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 ...	2002	12144650
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 ...	2002	12392911
the incidence and diversity of wolbachia in gallwasps (hymenoptera; cynipidae) on oak.	wolbachia bacteria infect approximately 20% of all insect species, and cause a range of alterations to host reproduction, including imposition of thelytoky. the incidence and phenotypic impact of wolbachia remains to be established in many insect taxa, and considerable research effort is currently focused on its association with particular reproductive modes and the relative importance of the various pathways via which infection occurs. gallwasps represent an attractive system for addressing the ...	2002	12207731
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 ...	2002	12537121
[river blindness: not only the work of onchocerca volvulus?].		2002	12102035
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 ...	2002	12180086
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 ...	2002	12534342
wolbachia endosymbiotic bacteria of filarial nematodes. a new insight into disease pathogenesis and control.	filarial nematodes are parasitic worms that cause some of the most devastating of all tropical diseases such as elephantiasis and river blindness. studies on the inflammatory pathogenesis of filarial disease have shown that endotoxin-like activity derived from endosymbiotic wolbachia bacteria is the major inflammatory stimulus of filarial nematodes. wolbachia appear to have evolved as essential symbionts of their filarial nematode hosts. antibiotic depletion of bacteria shows that they are requi ...	2002	12234534
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 ...	2002	12573064
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 ...	2002	12243742
use of tetracycline in larval diet to study the effect of wolbachia on host fecundity and clarify taxonomic status of trichogramma species in cured bisexual lines.	endosymbionts of the genus wolbachia were efficiently cured from trichogramma species by incorporating 0.02% tetracycline into the artificial diet used to rear larvae. use of this technique yielded stable cured lines (bisexual and arrhenotokous lines) in which no wolbachia organisms were detected by pcr for up to 14 generations after curing. four cured strains of trichogramma pretiosum showed a significantly lower total fecundity compared to their wolbachia-infected counterpart. however, the fec ...	2002	12234537
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 ...	2002	12440772
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 ...	2002	12449484
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 ...	2002	12454075
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 ...	2002	12487358
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 ...	2002	12625936
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 ...	2002	12421415
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 ...	2002	12534211
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 ...	2002	12427319
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 ...	2002	12234541
the distribution and proliferation of the intracellular bacteria wolbachia during spermatogenesis in drosophila.	wolbachia is a cytoplasmically inherited alpha-proteobacterium found in a wide range of host arthropod and nematode taxa. wolbachia infection in drosophila is closely associated with the expression of a unique form of post-fertilization lethality termed cytoplasmic incompatibility (ci). this form of incompatibility is only expressed by infected males suggesting that wolbachia exerts its effect during spermatogenesis. the growth and distribution of wolbachia throughout sperm development in indivi ...	2002	11804774
does fertilization in the filarial nematode dirofilaria immitis occur through endocytosis of spermatozoa?	information on the ultrastructural details of fertilization in filarial nematodes are still unavailable. here we report new data on this process in dirofilaria immits, the heartworm of dogs and cats. electron microscopy allowed us to observe oocytes engulfing spermatozoa through an endocytosis-like process. we also observed spermatozoa inside the oocytes which still possessed their plasma membrane and which were clearly enveloped by a further membrane, likely derived from the endocytosis process ...	2002	11811805
characterization of wolbachia host cell range via the in vitro establishment of infections.	maternally transmitted bacteria of the genus wolbachia are obligate, intracellular symbionts that are frequently found in insects and cause a diverse array of reproductive manipulations, including cytoplasmic incompatibility, male killing, parthenogenesis, and feminization. despite the existence of a broad range of scientific interest, many aspects of wolbachia research have been limited to laboratories with insect-rearing facilities. the inability to culture these bacteria outside of the invert ...	2002	11823204
evolutionary biology. timing is everything for wolbachia hosts.		2002	12004092
the role of endosymbiotic wolbachia bacteria in the pathogenesis of river blindness.	parasitic filarial nematodes infect more than 200 million individuals worldwide, causing debilitating inflammatory diseases such as river blindness and lymphatic filariasis. using a murine model for river blindness in which soluble extracts of filarial nematodes were injected into the corneal stroma, we demonstrated that the predominant inflammatory response in the cornea was due to species of endosymbiotic wolbachia bacteria. in addition, the inflammatory response induced by these bacteria was ...	2002	11884755
infectious disease. new culprit emerges in river blindness.		2002	11884722
how many wolbachia supergroups exist?		2002	11861893
prevailing triple infection with wolbachia in callosobruchus chinensis (coleoptera: bruchidae).	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 thr ...	2002	11856419
wolbachia density and virulence attenuation after transfer into a novel host.	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 transf ...	2002	11880639
field prevalence of wolbachia in the mosquito vector aedes albopictus.	the endosymbiotic bacteria in the genus wolbachia have been proposed as a potential candidate to deliver pathogen-blocking genes into natural populations of medically important insects. the successful application of wolbachia in insect vector control depends on the ability of the agent to successfully invade and maintain itself at high frequency under field conditions. here, we evaluated the prevalence of wolbachia infections in a field population of the wolbachia-superinfected mosquito aedes al ...	2002	12135259
wolbachia dna recognition.		2002	11965304
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 ...	2002	12140246
infection polymorphism and cytoplasmic incompatibility in hymenoptera-wolbachia associations.	most cases of wolbachia infection so far documented in haplodiploid hymenoptera are associated with parthenogenesis induction. only three examples of wolbachia-mediated cytoplasmic incompatibility (ci) have been reported, resulting either in haploidisation of fertilised eggs, which develop into viable males, or in their death. to better document this variability, we studied two new wolbachia-wasp associations involving drosophila parasitoids. in trichopria cf. drosophilae, individuals are infect ...	2002	11986872
divergence of mitochondrial dna is not corroborated by nuclear dna, morphology, or behavior in drosophila simulans.	we ask whether the observed mitochondrial dna (mtdna) population subdivision of drosophila simulans is indicative of organismal structure or of specific processes acting on the mitochondrial genome. factors either intrinsic or extrinsic to the host genome may influence the evolutionary dynamics of mtdna. potential intrinsic factors include adaptation of the mitochondrial genome and of nucleomitochondrial gene complexes specific to the local environment. an extrinsic force that has been shown to ...	2002	11989683
humoral immune response of simulium damnosum s.l. following filarial and bacterial infections.	the time-course of the humoral immune response of female blackflies after a challenge with bacteria, different onchocerca microfilariae species, bacterial endotoxin and microfilarial extract was investigated. strong bacteriolytic and growth inhibition activities against the gram-positive bacterium micrococcus luteus were induced by all agents. specific differences were found in activity levels and time-course. notably the endotoxin lipopolysaccharide (lps) induced a very early, profound bacterio ...	2002	12403324
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 ...	2002	12406252
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 ...	2002	12296954
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 ...	2002	12543723
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 ...	2002	12625925
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 ...	2002	12652910
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 ...	2002	12507486
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 ...	2002	12389718
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 ...	2002	12856318
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 ...	2002	12701381
[molecular diagnostic techniques of wolbachia].	wolbachia is a common and widespread group of bacteria found in reproductive tissues of arthropods. these bacteria are transmitted through the cytoplasm of eggs and have evolved various mechanisms for manipulating reproduction of their hosts. because of important relationship with some major biological issues and implication of biological control and genetic engineering, the study of wolbachia has under gone an explosive growth in recent years. a tremendous progress has been made based on the ad ...	2002	16118145
effects of wolbachia on genetic divergence between populations: mainland-island model.	cytoplasmic incompatibility (ci) induced by intracellular bacteria is a possible mechanism for speciation. growing empirical evidence suggests that bacteria of the group wolbachia may indeed act as isolating factors in recent insect speciation. wolbachia are cytoplasmically transmitted and can cause uni- or bidirectional ci. we present a mainland-island model to investigate how much impact wolbachia can have on genetic divergence between populations. in the first scenario we assume that the isla ...	2002	21708727
distribution of wolbachia within drosophila reproductive tissue: implications for the expression of cytoplasmic incompatibility.	a pcr based quantitative assay was used to determine wolbachia infection levels in three different drosophila strains. in addition, confocal microscopy was used to confirm and calibrate these results. wolbachia infection levels ranged from 2,600 to 18,500 per egg. single ovaries and testes from each of the three strains were also assayed using the calibrated quantitative pcr assay. a general correlation was found between bacterial levels in eggs and those found in ovaries and testis. these infec ...	2002	21708726
the effect of wolbachia on genetic divergence between populations: models with two-way migration.	wolbachia are intracellular bacteria that cause various reproduction alterations in their hosts, including cytoplasmic incompatibility (ci), an incompatibility between sperm and egg that typically results in embryonic death. we investigate theoretically the effects of wolbachia-induced bidirectional ci on levels of divergence between two populations, where there is migration in both directions and differential selection at a single locus. the main findings are as follows: wolbachia differences i ...	2002	18707453
which way to manipulate host reproduction? wolbachia that cause cytoplasmic incompatibility are easily invaded by sex ratio-distorting mutants.	the bacterium wolbachia manipulates its hosts by inducing cytoplasmic incompatibility (ci), where zygotes formed from crosses between uninfected mothers and infected fathers die. in addition, it distorts the host's sex ratio via male killing, parthenogenesis induction, or feminization. here, we model transitions between these states, examining the evolution of mutants of ci strains that retain both the ability to induce and resist ci but, in addition, cause sex ratio distortion. the model shows ...	2002	18707445
absence of wolbachia in nonfilariid nematodes.	intracellular bacteria of the genus wolbachia are among the most abundant endosymbionts on the planet, occurring in at least two major phyla-the arthropoda and nematoda. current surveys of wolbachia distribution have found contrasting patterns within these groups. whereas wolbachia are widespread and occur in all three major subphyla of arthropods, with estimates placing them in at least several million arthropod species, the presence of nematodes carrying wolbachia is currently confined to the ...	2003	19262760
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 ...	2003	12816546
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 ...	2003	12866789
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 ...	2003	12871912
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.	2003	12941392
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 ...	2003	12943116
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 ...	2003	12803629
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 ...	2003	12803636
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 ...	2003	12753223
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 ...	2003	12964989
removal of wolbachia from brugia pahangi is closely linked to worm death and fecundity but does not result in altered lymphatic lesion formation in mongolian gerbils (meriones unguiculatus).	approximately 30 years ago, researchers reported intracellular bacteria in filarial nematodes. these bacteria are relatives of the arthropod symbiont wolbachia and occur in many filarial nematodes, including brugia pahangi and brugia malayi. wolbachia bacteria have been implicated in a variety of roles, including filaria development and fecundity and the pathogenesis of lymphatic lesions associated with filarial infections. however, the role of the bacteria in worm biology or filarial disease is ...	2003	14638788
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 ...	2003	12965021
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 ...	2003	12753632
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 ...	2003	13678706
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 ...	2003	12748849
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 ...	2003	12860672
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 ...	2003	12860708
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. ...	2003	13678709
evolution 2003 meeting. genetic deficiency blamed on bacteria.		2003	12881548
control of filarial infections: not the beginning of the end, but more research is needed.	infections with the filarial nematodes affect more than 150 million people mainly in the tropics. the very successful efforts to control filarial infections, however, have to be sustained by new tools that require long-term commitment to research. this review, focusing on reports from 2002 and 2003, highlights recent advances in research on immunology, understanding of pathogenesis and drug development in lymphatic filariasis and onchocerciasis research with potential relevance to the generation ...	2003	14501992
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 ...	2003	12750334
a bacterial symbiont in the bacteroidetes induces cytoplasmic incompatibility in the parasitoid wasp encarsia pergandiella.	vertically transmitted symbionts of arthropods have been implicated in several reproductive manipulations of their hosts. these include cytoplasmic incompatibility (ci), parthenogenesis induction in haplodiploid species (pi), feminization and male killing. one symbiont lineage in the alpha-proteobacteria, wolbachia, is the only bacterium known to cause all of these effects, and has been thought to be unique in causing ci, in which the fecundity of uninfected females is reduced after mating with ...	2003	14561283
no variation for wolbachia-induced hybrid breakdown in two populations of a spider mite.	wolbachia are cytoplasmically transmitted bacteria that infect several species of mites. in the two-spotted spider mite tetranychus urticae koch this symbiont can induce reproductive incompatibility. wolbachia-induced reproductive incompatibility is observed in crosses between wolbachia-infected (w) males and uninfected (u) females. this incompatibility is expressed in f1 broods as male-biased sex ratios, an effect called cytoplasmic incompatibility (ci). however, in the two-spotted spider mite, ...	2003	14580056
wolbachia infections of the whitefly bemisia tabaci.	we report the first systematic survey for the presence of wolbachia endosymbionts in aphids and whiteflies, particularly different populations and biotypes of bemisia tabaci. additional agriculturally important species included were predator species, leafhoppers, and lepidopterans. we used a polymerase chain reaction (pcr)-based detection assay with ribosomal 16s rdna and wolbachia cell surface protein (wsp) gene primers. wolbachia were detected in a number of whitefly populations and species, w ...	2003	14506854
immunopathogenesis of onchocerca volvulus keratitis (river blindness): a novel role for tlr4 and endosymbiotic wolbachia bacteria.	infection with the parasitic nematode onchocerca volvulus is associated with inflammation of the skin and cornea that can lead to blindness. corneal damage is thought to occur as a result of the host inflammatory responses to degenerating microfilariae in the eye. we have utilized a murine model of corneal inflammation (keratitis) to investigate the immune and inflammatory responses associated with river blindness. soluble extracts of o. volvulus, a filarial species that contains the endosymbion ...	2003	14733727
wolbachia infection and the expression of cytoplasmic incompatibility in sandflies (diptera: psychodidae) from egypt.	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 tetracyclin ...	2003	14511562
molecular and electron microscopic identification of wolbachia in culex pipiens complex populations from the upper rhine valley, germany, and cebu city, philippines.	we detected wolbachia infections in culex pipiens complex mosquitoes from the upper rhine valley, germany, and cebu city, philippines, with the use of polymerase chain reaction (pcr) amplification of the 16s rdna of the bacteria and further confirmation by electron microscopy. species of 5 different autogenous and anautogenous populations of culex pipiens from germany and 1 population of culex quinquefasciatus from the philippines were used in this study. larvae were sampled from different local ...	2003	14524541
diversity of wolbachia endosymbionts in heteropteran bugs.	an extensive survey of wolbachia endosymbionts in japanese terrestrial heteropteran bugs was performed by pcr detection with universal primers for wsp and ftsz genes of wolbachia, cloning of the pcr products, restriction fragment length polymorphism analysis of infecting wolbachia types, and molecular phylogenetic characterization of all the detected wolbachia strains. of 134 heteropteran species from 19 families examined, wolbachia infection was detected in 47 species from 13 families. from the ...	2003	14532065
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 ...	2003	14615218
the distribution and evolutionary history of wolbachia infection in native and introduced populations of the invasive argentine ant (linepithema humile).	wolbachia pipientis is a maternally transmitted bacterium that often alters the life history of its insect host to maximize transmission to subsequent generations. here we report on the frequency and distribution of wolbachia infection in a widespread invasive species, the argentine ant (linepithema humile). we screened 1175 individual argentine ants from 89 nests on five continents and several islands, including numerous locations in both the native (south american) and introduced ranges. we de ...	2003	14629385
sorting out the effects of wolbachia, genotype and inbreeding on life-history traits of a spider mite.	wolbachia bacteria manipulate host reproduction by inducing cytoplasmic incompatibility (ci) and sex ratio distortion. wolbachia are transmitted from mother to offspring through the cytoplasm of the egg. therefore, reproduction of wolbachia is tightly coupled to reproduction of its host. mathematical analysis predicts that in the course of evolution, traits that reduce the physiological costs of the infection will be selectively favored. for a wolbachia-host system to evolve, traits under select ...	2003	14635812
host-specific wolbachia strains in widespread populations of phlebotomus perniciosus and p. papatasi (diptera: psychodidae), and prospects for driving genes into these vectors of leishmania.	a single strain of wolbachia (alpha-proteobacteria, rickettsiales) was found in widespread geographical populations of each of two phlebotomus species, within which there was no indication of 'infectious speciation'. the two strains were identified by sequencing a fragment of wsp (a major surface protein gene), amplified by polymerase chain reaction from dna extracted from the body parts of individual sandflies. infection rates were high in the males and females of both sandflies, but they were ...	2003	14641977
influence of two wolbachia strains on population structure of east african drosophila simulans.	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 associa ...	2003	14704179
development of a physical and genetic map of the virulent wolbachia strain wmelpop.	we report here the construction of a physical and genetic map of the virulent wolbachia strain, wmelpop. this map was determined by ordering 28 chromosome fragments that resulted from digestion with the restriction endonucleases fsei, apai, smai, and asci and were resolved by pulsed-field gel electrophoresis. southern hybridization was done with 53 wolbachia-specific genes as probes in order to determine the relative positions of these restriction fragments and use them to serve as markers. comp ...	2003	14645266
presence of wolbachia endosymbionts in microfilariae of wuchereria bancrofti (spirurida: onchocercidae) from different geographical regions in india.	in view of the recent discovery of rickettsial endosymbionts, wolbachia in lymphatic filarial parasites, wuchereria bancrofti and brugia malayi and subsequently of their vital role in the survival and development of the latter, antibiotics such as tetracycline are being suggested for the treatment of lymphatic filariasis, by way of eliminating the endosymbiont. but, it is essential to assess their presence in parasites from areas endemic for lymphatic filariasis before such a new control tool is ...	2003	15049082
proinflammatory cytokines dominate the early immune response to filarial parasites.	although the early human immune response to the infective-stage larvae (l3) of brugia malayi has not been well-characterized in vivo (because of the inability to determine the precise time of infection), the consensus has been that it must involve a predominant th2 environment. we have set up an in vitro system to study this early immune response by culturing pbmc from unexposed individuals with live l3 of b. malayi. after 24 h of culture, t cell responses were examined by flow cytometry and by ...	2003	14662876
culture and phenotypic characterization of a wolbachia pipientis isolate.	the recent isolation of wolbachia pipientis in the continuous cell line aa23, established from eggs of a strain of the asian tiger mosquito aedes albopictus, allowed us to perform extensive characterization of the isolate. bacterial growth could be obtained in c6/36, another a. albopictus cell line, at 28 degrees c and in a human embryonic lung fibroblast monolayer at 28 and 37 degrees c, confirming that its host cell range is broader than was initially thought. the bacteria were best visualized ...	2003	14662922
immunological role of the endosymbionts of dirofilaria immitis: the wolbachia surface protein activates canine neutrophils with production of il-8.	filarial nematodes, including dirofilaria immitis and d. repens, harbour intracellular bacteria belonging to the genus wolbachia. these bacteria have been implicated in the pathogenesis of filarial diseases, possibly through their endotoxins. recent studies have shown that a major surface protein of wolbachia (wsp) induces a specific igg response in hosts infected by d. immitis. wsp from the wolbachia of d. immitis was produced in recombinant form. the purified protein was used in stimulation as ...	2003	14597281
sexual mosaics induced by tetracycline treatment in the wolbachia-infected adzuki bean borer, ostrinia scapulalis.	wolbachia-infected ostrinia scapulalis (lepidoptera: crambidae) females generate all-female or nearly all-female broods. curing the infection by tetracycline treatment during larval stages results in the generation of all-male broods in the next generation. here we show that sexually mosaic offspring are produced by wolbachia-infected females treated with tetracycline at the adult stage. the sexual mosaics had wings that were composed of distinctive female and male sectors. besides wings, the se ...	2003	14663517
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 ...	2003	14512953
strain-specific regulation of intracellular wolbachia density in multiply infected insects.	vertically transmitted symbionts suffer a severe reduction in numbers when they pass through host generations, resulting in genetic homogeneity or even clonality of their populations. wolbachia endosymbionts that induce cytoplasmic incompatibility in their hosts depart from this rule, because cytoplasmic incompatibility actively maintains multiple infection within hosts. hosts and symbionts are thus probably under peculiar selective pressures that must shape the way intracellular bacterial popul ...	2003	14629360
mitochondrial and wolbachia markers for the sandfly phlebotomus papatasi: little population differentiation between peridomestic sites and gerbil burrows in isfahan province, iran.	in iran, phlebotomus papatasi (scopoli) (diptera: psychodidae) is the main vector of leishmania major yakimoff & schokhor (kinetoplastida: trypanosomatidae), the causative agent of rural zoonotic cutaneous leishmaniasis. this sandfly is abundant both in villages and in the burrows of the main reservoir host, the gerbil rhombomys opimus (licht.) (rodentia: gerbillidae). populations of p. papatasi were sampled from the edges of villages in isfahan province, using cdc miniature light traps in perid ...	2003	14651648
two kinds of sex ratio distorters in a moth, ostrinia scapulalis.	we surveyed female-biased sex ratio traits (sr traits) in a moth, ostrinia scapulalis (lepidoptera: crambidae) from six geographic locations in japan. a small proportion (8.3%) of females showed the sr trait. about half of them were associated with a wolbachia infection (srw+), whereas the remaining ones were not (srw-). no significant differences in frequencies were detected among locations and years for either srw+ or srw- females. in srw+ matrilines, the sr trait was inherited. curing the wol ...	2003	14663516
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 ...	2003	12710612
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 ...	2003	12684759
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 ...	2003	12522425
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 ...	2003	12655178
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 ...	2003	12933853
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 ...	2003	12743802