Publications

mutualistic wolbachia infection in aedes albopictus: accelerating cytoplasmic drive.	maternally inherited rickettsial symbionts of the genus wolbachia occur commonly in arthropods, often behaving as reproductive parasites by manipulating host reproduction to enhance the vertical transmission of infections. one manipulation is cytoplasmic incompatibility (ci), which causes a significant reduction in brood hatch and promotes the spread of the maternally inherited wolbachia infection into the host population (i.e., cytoplasmic drive). here, we have examined a wolbachia superinfecti ...	2002	11901124
history of infection with different male-killing bacteria in the two-spot ladybird beetle adalia bipunctata revealed through mitochondrial dna sequence analysis.	the two-spot ladybird beetle adalia bipunctata (coleoptera: coccinellidae) is host to four different intracellular maternally inherited bacteria that kill male hosts during embryogenesis: one each of the genus rickettsia (alpha-proteobacteria) and spiroplasma (mollicutes) and two distinct strains of wolbachia (alpha-proteobacteria). the history of infection with these male-killers was explored using host mitochondrial dna, which is linked with the bacteria due to joint maternal inheritance. two ...	2002	11901123
the effect of wolbachia-induced cytoplasmic incompatibility on host population size in natural and manipulated systems.	obligate, intracellular bacteria of the genus wolbachia often behave as reproductive parasites by manipulating host reproduction to enhance their vertical transmission. one of these reproductive manipulations, cytoplasmic incompatibility, causes a reduction in egg-hatch rate in crosses between individuals with differing infections. applied strategies based upon cytoplasmic incompatibility have been proposed for both the suppression and replacement of host populations. as wolbachia infections occ ...	2002	11886634
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
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
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
the stockholm populations of adalia bipunctata (l) (coleoptera: coccinellidae)--a case of extreme female-biased population sex ratio.	the genetic composition and sex ratio in the stockholm populations of adalia bipunctata have been studied. the overall frequency of melanics is 3.2%, which is significantly lower than in the populations of st. petersburg and other large cities along the baltic sea. the secondary sex ratio in the stockholm populations is female-biased 82:18. more than half of a. bipunctata females are infected with the male-killing spiroplasma bacterium. beetles of the co-existing species adalia decempunctata are ...	2001	11833290
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
sequencing and analysis of a 63 kb bacterial artificial chromosome insert from the wolbachia endosymbiont of the human filarial parasite brugia malayi.	wolbachia endosymbiotic bacteria are widespread in filarial nematodes and are directly involved in the immune response of the host. in addition, antibiotics which disrupt wolbachia interfere with filarial nematode development thus, wolbachia provide an excellent target for control of filariasis. a 63.1 kb bacterial artificial chromosome insert, from the wolbachia endosymbiont of the human filarial parasite brugia malayi, has been sequenced using the new england biolabs inc. genome priming system ...	2002	11812492
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
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
on the mod resc model and the evolution of wolbachia compatibility types.	cytoplasmic incompatibility (ci) is induced by the endocellular bacterium wolbachia. it results in an embryonic mortality occurring when infected males mate with uninfected females. the mechanism involved is currently unknown, but the mod resc model allows interpretation of all observations made so far. it postulates the existence of two bacterial functions: modification (mod) and rescue (resc). the mod function acts in the males' germline, before wolbachia are shed from maturing sperm. if sperm ...	2001	11779785
a novel technique for removing wolbachia infections from aedes albopictus (diptera: culicidae).	intracellular bacteria of the genus wolbachia often behave as reproductive parasites by manipulating host reproduction to enhance the vertical transmission of infections. wolbachia infections in aedes albopictus (skuse) cause a reproductive manipulation known as cytoplasmic incompatibility, which can reduce brood hatch. because field populations of ae. albopictus are naturally infected, studies of wolbachia-induced effects on ae. albopictus reproduction and fitness require that wolbachia be arti ...	2001	11761383
reorganization of genera in the families rickettsiaceae and anaplasmataceae in the order rickettsiales: unification of some species of ehrlichia with anaplasma, cowdria with ehrlichia and ehrlichia with neorickettsia, descriptions of six new species combinations and designation of ehrlichia equi and 'hge agent' as subjective synonyms of ehrlichia phagocytophila.	the genera anaplasma, ehrlichia, cowdria, neorickettsia and wolbachia encompass a group of obligate intracellular bacteria that reside in vacuoles of eukaryotic cells and were previously placed in taxa based upon morphological, ecological, epidemiological and clinical characteristics. recent genetic analyses of 16s rrna genes, groesl and surface protein genes have indicated that the existing taxa designations are flawed. all 16s rrna gene and groesl sequences deposited in genbank prior to 2000 a ...	2001	11760958
[bacterial symbionts (wolbachia) of filarial nematodes: implications for the treatment and pathology of filariasis].	filarial nematodes harbour intracellular, gram-negative bacteria belonging to the genus wolbachia. these bacteria have been observed in various species of filariae, including the main filariasis agents of humans and animals. it has been suggested that wolbachia could play an important role in the biology of filarial nematodes and could be implicated in the pathogenesis of filarial diseases. wolbachia could thus represent a target for the control of filariasis and key to the understanding of thes ...	2001	11758285
wolbachia-mediated sperm modification is dependent on the host genotype in drosophila.	estimates of wolbachia density in the eggs, testes and whole flies of drosophilid hosts have been unable to predict the lack of cytoplasmic incompatibility (ci) expression in so-called mod(-) variants. consequently, the working hypothesis has been that ci expression, although related to wolbachia density, is also governed by unknown factors that are influenced by both host and bacterial genomes. here, we compare the behaviour of the mod(-) over-replicating wolbachia popcorn strain in its native ...	2001	11749711
severe reactions to filarial chemotherapy and release of wolbachia endosymbionts into blood.	wolbachia bacteria seem to have evolved as essential endosymbionts of their filarial nematode hosts. studies in mice have suggested that these bacteria are associated with systemic inflammatory reactions to filarial chemotherapy. we took blood samples from 15 indonesian patients before and after treatment with diethylcarbamazine for brugia malayi infection, and recorded the severity of any post-treatment inflammatory reactions. blood from all three patients with severe adverse reactions and from ...	2001	11741630
late male-killing phenomenon found in a japanese population of the oriental tea tortrix, homona magnanima (lepidoptera: tortricidae).	a female-biased sex ratio was found in the oriental tea tortrix, homona magnanima (lepidoptera: tortricidae), in tsukuba, ibaraki, japan. there was no difference in mean egg hatch between the all-female and normal strains. greater than 50% mortality was observed in the all-female strain larvae, suggesting that female-only broods are produced as a result of late male-killing. the female-biased sex ratio was maternally inherited and maintained, even when females were backcrossed with males of the ...	2001	11737291
wolbachia diversity in the porcellionides pruinosus complex of species (crustacea: oniscidea): evidence for host-dependent patterns of infection.	porcellionides pruinosus is a cosmopolitan woodlouse. it is known to exhibit patterns of geographical variation between populations, and has been suspected to consist of several very closely related species. this species was found to carry wolbachia endosymbionts, alpha-proteobacteria which are known to modify the reproduction of their crustacean hosts by inducing cytoplasmic incompatibility or feminization. in the p. pruinosus complex, wolbachia induced feminization, but two different patterns ...	2001	11737290
understanding patterns of genetic diversity in the oak gallwasp biorhiza pallida: demographic history or a wolbachia selective sweep?	the endosymbiont wolbachia can be responsible for selective sweeps on mitochondrial dna variability within species. similar signals can also result from demographic processes, although crucially the latter affect nuclear as well as mitochondrial loci. here we present data on wolbachia infection status and phylogeographic patterning for a widely distributed insect host, the oak gallwasp biorhiza pallida (hymenoptera: cynipidae). two hundred and eighteen females from eight european countries were ...	2001	11737276
wolbachia: evolutionary novelty in a rickettsial bacteria.	although closely related, the alpha-proteobacteria wolbachia and the rickettsiaceae (rickettsia and ehrlichia), employ different evolutionary life history strategies. wolbachia are obligate endocellular symbionts that infect an extraordinary host range and, in contrast to the infectious and pathogenic rickettsia and ehrlichia, profoundly influence host reproductive biology.	2001	11734058
sex ratio and wolbachia infection in the ant formica exsecta.	sex allocation data in social hymenoptera provide some of the best tests of kin selection, parent-offspring conflict and sex ratio theories. however, these studies critically depend on controlling for confounding ecological factors and on identifying all parties that potentially manipulate colony sex ratio. it has been suggested that maternally inherited parasites may influence sex allocation in social hymenoptera. if the parasites can influence sex allocation, infected colonies are predicted to ...	2001	11703514
what causes inefficient transmission of male-killing wolbachia in drosophila?	selfish genetic elements that distort the sex ratio are common in arthropods. theory predicts they will invade and spread to fixation if they are vertically transmitted with perfect fidelity, potentially leading to host extinction. for inherited microorganisms that distort the sex ratio, inefficient vertical transmission or incomplete sex ratio distorting ability is required for host persistence. however, the relative roles of genetic and environmental factors in permitting the survival of male ...	2001	11703513
one in the eye for river blindness.		2001	11685890
wolbachia-induced parthenogenesis in a genus of phytophagous mites.	the vertically transmitted endosymbiotic bacterium wolbachia modifies host reproduction in several ways in order to enhance its own spread. one such modification results in the induction of parthenogenesis, where males, which are unable to transmit wolbachia, are not produced. interestingly, parthenogenesis-inducing wolbachia have only been found within haplodiploid insects and it is not known whether this exclusivity is the result of functional constraints of wolbachia. here we find a unique pa ...	2001	11674872
a field cage test of the effects of the endosymbiont wolbachia on drosophila melanogaster.	wolbachia endosymbionts are known to affect the fitness of their hosts, but most of this information is from laboratory studies. in drosophila melanogaster, wolbachia frequencies vary clinically in frequency in australia and may confound climatic adaptation. here we use field cages in a reciprocal exchange design to test for wolbachia effects in d. melanogaster in winter at temperate and tropical sites. infected flies of both populations had a lower fecundity in tropical north queensland, whilst ...	2001	11595053
a newly discovered bacterium associated with parthenogenesis and a change in host selection behavior in parasitoid wasps.	the symbiotic bacterium wolbachia pipientis has been considered unique in its ability to cause multiple reproductive anomalies in its arthropod hosts. here we report that an undescribed bacterium is vertically transmitted and associated with thelytokous parthenogenetic reproduction in encarsia, a genus of parasitoid wasps. although wolbachia was found in only one of seven parthenogenetic encarsia populations examined, the "encarsia bacterium" (eb) was found in the other six. among seven sexually ...	2001	11592990
within-species diversity of wolbachia-induced cytoplasmic incompatibility in haplodiploid insects.	wolbachia-induced cytoplasmic incompatibility (ci) can have two consequences in haplodiploid insects: fertilized eggs either die (female mortality, fm) or they develop into haploid males (male development, md). origin of this diversity remains poorly understood, but current hypotheses invoke variation in damage suffered by paternal chromosomes in incompatible eggs, thus intermediate ci types should be expected. here, we show the existence of such a particular ci type. in the parasitoid wasp lept ...	2001	11580031
sexually antagonistic cytonuclear fitness interactions in drosophila melanogaster.	theoretical and empirical studies have shown that selection cannot maintain a joint nuclear-cytoplasmic polymorphism within a population except under restrictive conditions of frequency-dependent or sex-specific selection. these conclusions are based on fitness interactions between a diploid autosomal locus and a haploid cytoplasmic locus. we develop a model of joint transmission of x chromosomes and cytoplasms and through simulation show that nuclear-cytoplasmic polymorphisms can be maintained ...	2001	11560895
wolbachia infection shared among planthoppers (homoptera: delphacidae) and their endoparasite (strepsiptera: elenchidae): a probable case of interspecies transmission.	wolbachia, a group of parasitic bacteria of arthropods, are believed to be horizontally transmitted among arthropod taxa. we present a new probable example of interspecies horizontal transmission of wolbachia by way of an endoparasite based on the conformity of wolbachia gene sequences. field samples of two rice planthoppers, laodelphax striatellus and sogatella furcifera possessed identical wolbachia. among three major endoparasites of planthoppers, a strepsipteran, elenchus japonicus, harboure ...	2001	11555254
wolbachia in filarial nematodes: evolutionary aspects and implications for the pathogenesis and treatment of filarial diseases.	the presence of intracellular bacteria in the body of various species of filarial nematodes, including important parasites such as brugia malayi, dirofilaria immitis, and onchocerca volvulus, was observed as early as the mid-1970s. these bacteria were shown to be transovarially transmitted (from the female worm to the offspring) and to be present in significant amounts in the body of the nematode. as highlighted by their discoverers, the potential importance of these bacteria is fairly obvious: ...	2001	11516587
wolbachia endosymbiont responsible for cytoplasmic incompatibility in a terrestrial crustacean: effects in natural and foreign hosts.	wolbachia bacteria are vertically transmitted endosymbionts that disturb the reproduction of many arthropods thereby enhancing their spread in host populations. wolbachia are often responsible for changes of sex ratios in terrestrial isopods, a result of the feminization of genotypic males. here we found that the wolbachia hosted by cylisticus convexus (wcc) caused unidirectional cytoplasmic incompatibility (ci), an effect commonly found in insects. to understand the diversity of wolbachia-induc ...	2001	11488969
cytoplasmic incompatibility and maternal-haploid.		2001	11485804
doxycycline and eradication of microfilaremia in patients with loiasis.		2001	11485684
wolbachia bacteria in filarial immunity and disease.	lymphatic filarial nematodes are infected with endosymbiotic wolbachia bacteria. lipopolysaccharide from these bacteria is the major activator of innate inflammatory responses induced directly by the parasite. here, we propose a mechanism by which wolbachia initiates acute inflammatory responses associated with death of parasites, leading to acute filarial lymphangitis and adverse reactions to antifilarial chemotherapy. we also speculate that repeated exposure to acute inflammatory responses and ...	2001	11472559
immunological genomics of brugia malayi: filarial genes implicated in immune evasion and protective immunity.	filarial nematodes are metazoan parasites with genome sizes of> 100 million base pairs, probably encoding 15 000-20 000 genes. within this considerable gene complement, it seems likely that filariae have evolved a spectrum of immune evasion products which underpin their ability to live for many years within the human host. moreover, no suitable vaccine currently exists for human filarial diseases, and few markers have yet been established for diagnostic use. in this review, we bring together bio ...	2001	11472553
prospects and challenges in lymphatic filariasis.		2001	11472552
meet the herod bug.		2001	11452274
intracellular bacterial symbiosis in the genus sitophilus: the 'biological individual' concept revisited.	eukaryotic cells, as genetic entities, most often involve several physically associated genomes that direct the metabolic cell equilibrium. in the coleopteran insects of the genus sitophilus, in addition to the nucleus and the mitochondrial genomes, two other intracellular bacterial genomes belonging to the alpha and the gamma groups of proteobacteria are also present. coexisting with the eukaryotic host cell genomes, they intervene in the physiology and reproduction of the host. they are both t ...	2001	11446511
detection of serum igg antibodies specific for wolbachia surface protein in rhesus monkeys infected with brugia malayi.	the mechanism of lymphedema development in individuals with lymphatic filariasis is presently poorly understood. to investigate whether wolbachia, symbiotic bacteria living within filarial nematodes, may be involved in disease progression, wolbachia-specific immune responses were assayed in a group of brugia malayi-infected rhesus monkeys. serum igg antibodies specific for a major wolbachia surface protein (wsp) were detected in 2 of 12 infected monkeys. it is interesting that both of these monk ...	2001	11443570
wolbachia bacteria effects after experimental interspecific transfers in terrestrial isopods.	wolbachia bacteria are intracellular parasites, vertically transmitted from mothers to offspring through the cytoplasm of the eggs. they manipulate the reproduction of their hosts to increase in frequency in host populations. in terrestrial isopods for example, wolbachia are responsible for the full feminization of putative males, therefore increasing the proportion of females, the sex by which they are transmitted. vertical transmission, however, is not the only means for wolbachia propagation. ...	2001	11437528
one in the eye for river blindness.		2001	11435084
evolution. haploids--hapless or happening?		2001	11431554
recombination confounds interpretations of wolbachia evolution.	wolbachia are vertically transmitted bacteria known from arthropods and nematode worms, which are maintained in host populations because they either physiologically benefit infected individuals or parasitically manipulate their reproduction. the different manipulation phenotypes are scattered across the wolbachia phylogeny, suggesting that there have been multiple evolutions of similar phenotypes. this conclusion relies on the assumption of an absence of recombination between bacterial strains, ...	2001	11429144
wolbachia in the asian rice gall midge, orseolia oryzae (wood-mason): correlation between host mitotypes and infection status.	using a pcr-based method, we detected wolbachia in the asian rice gall midge. furthermore, results showed that all females across all biotypes are infected with wolbachia. however, all male flies are not infected and show different infection frequency in different biotypes. we have also identified three mitotypes, in the rice gall midge, based on drai restriction pattern of a portion of the 12s rrna gene that was pcr amplified using primers specific to this gene. all the females and infected mal ...	2001	11422512
molecular identification of wolbachia from the filarial nematode mansonella ozzardi.	mansonella ozzardi, a filarial parasite of humans in latin america, has been shown to harbour intracellular bacteria not yet identified. here we show that these bacteria, like those of other filarial nematodes, belong to the genus wolbachia (alpha 2 proteobacteria; rickettsiales). their unambiguous placement in the wolbachia group was shown by 16s rdna sequence analysis. however, the exact position of the wolbachia from m. ozzardi relative to the other wolbachiae is not clear. indeed, 16s rdna s ...	2001	11403387
of filariasis, mice and men.		2001	11394345
nitric oxide synthase in filariae: demonstration of nitric oxide production by embryos in brugia malayi and acanthocheilonema viteae.	the radical gas nitric oxide (no) is synthesized by nitric oxide synthase (nos) from l-arginine and molecular oxygen. nitric oxide is an important signaling molecule in invertebrate and vertebrate systems. previously we have shown that nos is localized to more tissues in brugia malayi than has been reported in ascaris suum. in this paper, we analyze the distribution of nos in acanthocheilonema viteae, a filarial nematode that differs from b. malayi in that a. viteae females release microfilariae ...	2001	11384164
two male-killing wolbachia strains coexist within a population of the butterfly acraea encedon.	inherited bacteria that kill male hosts early in their development are known from five insect orders. we ask to what extent the incidence of male-killers might be restricted by the rate at which new host-parasite interactions arise, by testing whether multiple male-killers have invaded a single host species. in uganda, the butterflies acraea encedon and a. encedana are both infected by the same strain of male-killing wolbachia and there was no evidence of variation within the population. in tanz ...	2001	11380661
neutrophil accumulation around onchocerca worms and chemotaxis of neutrophils are dependent on wolbachia endobacteria.	unlike in many other helminth infections, neutrophilic granulocytes are major cellular components in the hosts immune response against filarial worms. the pathways that drive the immune response involving neutrophils are unclear. this study shows that wolbachia endobacteria (detectable by polyclonal antibodies against endobacterial heat shock protein 60 and catalase and by polymerase chain reaction being sensitive to doxycycline treatment) are direct and indirect sources of signals accounting fo ...	2001	11377205
how many species are infected with wolbachia? cryptic sex ratio distorters revealed to be common by intensive sampling.	inherited bacterial symbionts from the genus wolbachia have attracted much attention by virtue of their ability to manipulate the reproduction of their arthropod hosts. the potential importance of these bacteria has been underlined by surveys, which have estimated that 17% of insect species are infected. we examined whether these surveys have systematically underestimated the proportion of infected species through failing to detect the low-prevalence infections that are expected when wolbachia d ...	2001	11375098
wolbachia-mediated parthenogenesis in the predatory thrips franklinothrips vespiformis (thysanoptera: insecta).	wolbachia are bacterial endosymbionts in arthropods and filarial nematodes. they cause thelytoky, which is a form of parthenogenesis in which females produce females without males, in hymenopteran insects. infection of this parthenogenesis-inducing wolbachia has been restricted to the order hymenoptera, but was found in another insect order, thysanoptera. a parthenogenetic colony of a predatory thrips franklinothrips vespiformis (aeolothripidae) possessed b-group wolbachia. male progeny were pro ...	2001	11375084
wolbachia-induced cytoplasmic incompatibility in single- and superinfected aedes albopictus (diptera: culicidae).	maternally inherited bacteria of the genus volbachia can cause cytoplasmic incompatibility resulting in the developmental arrest of early embryos. previous studies have shown that both single- and superinfections of wolbachia naturally occur in populations of aedes albopictus (skuse). here, we report crossing experiments using three infection types occurring in ae. albopictus: uninfected, single-infected, and superinfected individuals. crosses were monitored over the lifetime of adults to detect ...	2001	11372962
depletion of wolbachia endobacteria in onchocerca volvulus by doxycycline and microfilaridermia after ivermectin treatment.	ivermectin is the drug used for mass chemotherapy of onchocerciasis within the who african programme for onchocerciasis control. this approach aims to eliminate the disease as a public health problem but using one dose per year may not completely interrupt transmission since it does not suppress microfilaridermia thoroughly enough. here we show that additional treatment with doxycycline, previously shown to sterilise adult female worms for a few months by depletion of symbiotic wolbachia endobac ...	2001	11356444
bacteriophage wo and virus-like particles in wolbachia, an endosymbiont of arthropods.	wolbachia are intracellular symbionts mainly found in arthropods, causing various sexual alterations on their hosts by unknown mechanisms. here we report the results that strongly suggest that wolbachia have virus-like particles of phage wo, which was previously identified as a prophage-like element in the wolbachia genome. wolbachia (strain wtai) infection in an insect was detected with the antibody against wsp, an outer surface protein of wolbachia, by fluorescence microscopy and immunoelectro ...	2001	11355885
removing symbiotic wolbachia bacteria specifically inhibits oogenesis in a parasitic wasp.	wolbachia are bacteria that live in the cells of various invertebrate species to which they cause a wide range of effects on physiology and reproduction. we investigated the effect of wolbachia infection in the parasitic wasp, asobara tabida nees (hymenoptera, braconidae). in the 13 populations tested, all individuals proved to be infected by wolbachia. the removal of wolbachia by antibiotic treatment had a totally unexpected effect-aposymbiotic female wasps were completely incapable of producin ...	2001	11353833
wolbachia. a tale of sex and survival.		2001	11352061
transfection of wolbachia in lepidoptera: the feminizer of the adzuki bean borer ostrinia scapulalis causes male killing in the mediterranean flour moth ephestia kuehniella.	two species of lepidoptera, ostrinia scapulalis and ephestia kuehniella, harbour wolbachia, which are maternally transmitted intracellular bacteria that often cause reproductive abnormalities in arthropods. while the infection in o. scapulalis causes conversion of genetic males into functional females (feminization), that in e. kuehniella induces cytoplasmic incompatibility. in the present study, we investigated the relative importance of host and wolbachia factors in the differential expression ...	2001	11345332
in vitro activity of antimicrobial agents against the endosymbiont wolbachia pipientis.	arthropod-transmitted (filarial) nematodes are important causes of disease in humans in tropical countries, yet no safe drug appropriate for mass delivery kills the adult worms. however, most filarial nematodes contain rickettsia-like bacteria of the genus wolbachia, and related bacteria also occur in insects. there is increasing evidence that these bacteria have significant functions in the biology of filarial nematodes. they are thus important targets in the search for antifilarial drugs and e ...	2001	11328780
recombination in wolbachia.	wolbachia are widely distributed intracellular bacteria that cause a number of reproductive alterations in their eukaryotic hosts. such alterations include the induction of parthenogenesis, feminization, cytoplasmic incompatibility, and male killing [1-11]. these important bacteria may play a role in rapid speciation in insects [12-14], and there is growing interest in their potential uses as tools for biological control and genetic manipulation of pests and disease vectors [15-16]. here, we sho ...	2001	11301253
do wolbachia infections play a role in unidirectional incompatibilities in a field cricket hybrid zone?	two closely related field crickets, gryllus firmus and g. pennsylvanicus, hybridize along an extensive north-south zone in the eastern united states. crosses between g. firmus males and g. pennsylvanicus females produce viable and fertile f1, but the reciprocal cross consistently fails to produce offspring. wolbachia, a bacterial parasite of arthropods that causes unidirectional incompatibilities in a variety of insect species, has been suggested as the cause of the observed incompatibility betw ...	2001	11298981
selfish element maintains sex in natural populations of a parasitoid wasp.	genomic conflicts between heritable elements with different modes of inheritance are important in the maintenance of sex and in the evolution of sex ratio. generally, we expect sexual populations to exhibit a 1:1 sex ratio. however, because of their biology, parasitoid wasps often exhibit a female-biased sex ratio. sex-ratio distorters can further alter this optimum, sometimes leading to the complete loss of sexual reproduction. in the parasitoid wasp trichogramma kaykai ca. 4-26% of females in ...	2001	11297179
wolbachia infections of phlebotomine sand flies (diptera: psychodidae).	old and new world phlebotomine sand fly species were screened for infection with wolbachia, intracellular bacterial endosymbionts found in many arthropods and filarial nematodes. of 53 samples representing 15 species, nine samples offour species were found positive for wolbachia by polymerase chain reaction amplification using primers for the wolbachia surface protein (wsp) gene. five of the wsp gene fragments from four species were cloned, sequenced, and used for phylogenetic analysis. these ws ...	2001	11296829
infection density of wolbachia and incompatibility level in two planthopper species, laodelphax striatellus and sogatella furcifera.	wolbachia, a bacterial endosymbiote of arthropods, causes cytoplasmic incompatibility (ci) in many insect species. ci traits were studied in two planthopper species, laodelphax striatellus and sogatella furcifera, and wolbachia densities in these planthopper species were calculated by quantitative pcr methods. the ci level of l. striatellus was quite high and even aged males strongly caused ci. in contrast, s. furcifera showed partial ci, and males lost their ability to cause ci with age. wolbac ...	2001	11267910
evolution. nota bene. wolbachia and wasp evolution.		2001	11253199
determination of wolbachia genome size by pulsed-field gel electrophoresis.	genome sizes of six different wolbachia strains from insect and nematode hosts have been determined by pulsed-field gel electrophoresis of purified dna both before and after digestion with rare-cutting restriction endonucleases. enzymes smai, apai, asci, and fsei cleaved the studied wolbachia strains at a small number of sites and were used for the determination of the genome sizes of wmelpop, wmel, and wmelcs (each 1.36 mb), wri (1.66 mb), wbma (1.1 mb), and wdim (0.95 mb). the wolbachia genome ...	2001	11244060
paternal chromosome incorporation into the zygote nucleus is controlled by maternal haploid in drosophila.	maternal haploid (mh) is a strict maternal effect mutation that causes the production of haploid gynogenetic embryos (eggs are fertilized but only maternal chromosomes participate in development). we conducted a cytological analysis of fertilization and early development in mh eggs to elucidate the mechanism of paternal chromosome elimination. in mh eggs, as in wild-type eggs, male and female pronuclei migrate and appose, the first mitotic spindle forms, and both parental sets of chromosomes con ...	2001	11237467
inherited microorganisms, sex-specific virulence and reproductive parasitism.	parasites show an amazing repertoire of adaptations, highlighted by complex life cycles that allow both survival in the host and transmission among hosts. however, there is one heterogeneous group of microorganisms whose adaptations are perhaps even more surprising: parthenogenesis induction, feminization of genetic males, killing of male hosts and sperm-mediated sterilization of uninfected eggs. the common feature of these microorganisms is their mode of transmission: inheritance from mother to ...	2001	11228015
wolbachia-induced incompatibility precedes other hybrid incompatibilities in nasonia.	wolbachia are cytoplasmically inherited bacteria that cause a number of reproductive alterations in insects, including cytoplasmic incompatibility, an incompatibility between sperm and egg that results in loss of sperm chromosomes following fertilization. wolbachia are estimated to infect 15-20% of all insect species, and also are common in arachnids, isopods and nematodes. therefore, wolbachia-induced cytoplasmic incompatibility could be an important factor promoting rapid speciation in inverte ...	2001	11217858
infectious speciation.		2001	11217844
antibiotics and wolbachia in filarial nematodes: antifilarial activity of rifampicin, oxytetracycline and chloramphenicol against onchocerca gutturosa, onchocerca lienalis and brugia pahangi.	the activity against filarial parasites of the antibiotics rifampicin, oxytetracycline and chloramphenicol was examined. in addition, transmission electron microscopy was used to study the effects of rifampicin and oxytetracycline on filarial tissues and on the endosymbiont bacterium, wolbachia. when tested in vitro at a concentration of 50.0 microm, each of the three antibiotics significantly reduced the motility levels of male onchocerca gutturosa. rifampicin, however, was the most active, vir ...	2000	11214099
mechanisms of conspecific sperm precedence in drosophila.	the postmating, prezygotic isolating mechanism known as conspecific sperm precedence (csp) may play an important role in speciation, and understanding the mechanism of csp is important in reconstructing its evolution. when a drosophila simulans female mates with both a d. simulans male and a d. mauritiana male, the vast majority of her progeny are fathered by d. simulans, regardless of the order of mating. the dearth of hybrid progeny does not result from inviability of eggs fertilized by hetero ...	2000	11209779
diseases of mites.	an overview is given of studies on diseases of mites. knowledge of diseases of mites is still fragmentary but in recent years more attention has been paid to acaropathogens, often because of the economic importance of many mite species. most research on mite pathogens concerns studies on fungal pathogens of eriophyoids and spider mites especially. these fungi often play an important role in the regulation of natural mite populations and are sometimes able to decimate populations of phytophagous ...	2000	11201358
wolbachia bacteria of filarial nematodes in the pathogenesis of disease and as a target for control.		2000	11198638
a phylogenetic analysis of filarial nematodes: comparison with the phylogeny of wolbachia endosymbionts.	infection with the endosymbiotic bacteria wolbachia is widespread in filarial nematodes. previous studies have suggested concordance between the phylogeny of wolbachia with that of their nematode hosts. however, there is only one published molecular phylogenetic study of filarial species, based on the 5s rrna gene spacer. the phylogeny proposed by this study is partially incongruent with previous classifications of filarial nematodes, based on morphological characters. furthermore, both traditio ...	2001	11197770
antigenic role of the endosymbionts of filarial nematodes: igg response against the wolbachia surface protein in cats infected with dirofilaria immitis.	filarial nematodes harbour intracellular endosymbiotic bacteria, which have been assigned to the genus wolbachia. these bacteria appear to play an important role in the pathogenesis of filarial diseases through their lipopolysaccharides. in view of the presence of wolbachia endosymbionts in the body of filarial nematodes, one might also expect that proteins from these bacteria play an antigenic role in humans and animals affected by filariases. to test this hypothesis, we produced in recombinant ...	2000	11197127
automictic parthenogenesis in the parasitoid venturia canescens (hymenoptera: ichneumonidae) revisited.	both arrhenotokous and thelytokous reproduction are known to occur in the parasitoid wasp venturia canescens. the cytological mechanism of thelytoky was previously reported to involve the formation of a restitution metaphase after the reduction division, but the exact nature of the subsequent divisions, whether reductional or equational, remained unclear. we reinvestigated the cytological mechanisms in a thelytokous strain collected in france. our observations confirm previous results, but an eq ...	2000	11195346
mosquito engineering. building a disease-fighting mosquito.	with resistance against insecticides on the rise and a u.n.-backed push to phase out ddt, several labs have embarked on the most ambitious and futuristic of all approaches to combat malaria: they hope to replace billions and billions of mosquitoes in the world's endemic areas with new strains, created in the lab, that would be "refractory," or unable to transmit plasmodium, the parasite that causes the disease. the idea is not that farfetched, these researchers claim.	2000	11183760
occurrence of novel verrucomicrobial species, endosymbiotic and associated with parthenogenesis in xiphinema americanum-group species (nematoda, longidoridae).	numerous micro-organisms have been described as cytoplasmic symbionts of eukaryotes. many so-called obligate endosymbionts rely exclusively on maternal (vertical or transovarial) transmission to maintain themselves, rendering them dependent on the host sex ratio, which they would tend to manipulate to their own advantage. the latter phenomenon is often associated with the presence of wolbachia pipientis (alpha-proteobacteria) in arthropods and nematodes. a potentially similar situation was disco ...	2000	11155997
physiological cost induced by the maternally-transmitted endosymbiont wolbachia in the drosophila parasitoid leptopilina heterotoma.	endosymbiotic bacteria of the genus wolbachia infect a number of invertebrate species in which they induce various alterations in host reproduction, mainly cytoplasmic incompatibility (ci). in contrast to most other maternally transmitted parasites, manipulation of host reproduction makes the spread of wolbachia possible even if they induce a physiological cost on their hosts. current studies have shown that fitness consequences of wolbachia infection could range from positive (mutualist) to neg ...	2000	11128800
wolbachia infections in native and introduced populations of fire ants (solenopsis spp.).	wolbachia are cytoplasmically inherited bacteria that induce a variety of effects with fitness consequences on host arthropods, including cytoplasmic incompatibility, parthenogenesis, male-killing and feminization. we report here the presence of wolbachia in native south american populations of the fire ant solenopsis invicta, but the apparent absence of the bacteria in introduced populations of this pest species in the usa. the wolbachia strains in native s. invicta are of two divergent types ( ...	2000	11122476
wolbachia neither induces nor suppresses transcripts encoding antimicrobial peptides.	wolbachia are intracellular maternally inherited microorganisms that are associated with reproductive abnormalities such as cytoplasmic incompatibility (ci), feminization and parthenogenesis in the various arthropod species they infect. surveys indicate that these bacteria infect more than 16% of all insect species as well as isopods, mites and nematodes, making wolbachia one of the most ubiquitous parasites yet described. however, nothing is known about the interactions of this bacterium with t ...	2000	11122472
expression of cytoplasmic incompatibility in drosophila simulans and its impact on infection frequencies and distribution of wolbachia pipientis.	the aim of this study is to examine the expression of cytoplasmic incompatibility and investigate the distribution and population frequencies of wolbachia pipientis strains in drosophila simulans. nucleotide sequence data from 16s rdna and a wolbachia surface protein coding sequence and cytoplasmic incompatibility assays identify four distinct wolbachia strains: wha, wri, wma, and wau. the levels of cytoplasmic incompatibility between six lines carrying these strains of bacteria and three contro ...	2000	11108593
distribution and evolution of bacteriophage wo in wolbachia, the endosymbiont causing sexual alterations in arthropods.	wolbachia are obligatory intracellular and maternally inherited bacteria, known to infect many species of arthropod. in this study, we discovered a bacteriophage-like genetic element in wolbachia, which was tentatively named bacteriophage wo. the phylogenetic tree based on phage wo genes of several wolbachia strains was not congruent with that based on chromosomal genes of the same strains, suggesting that phage wo was active and horizontally transmitted among various wolbachia strains. all the ...	2000	11080372
wolbachia-induced 'hybrid breakdown' in the two-spotted spider mite tetranychus urticae koch.	the most common post-zygotic isolation mechanism between populations of the phytophagous mite tetranychus urticae is 'hybrid breakdown', i.e. when individuals from two different populations are crossed, f1 hybrid females are produced, but f2 recombinant male offspring suffer increased mortality. two-spotted spider mites collected from two populations, one on rose and the other on cucumber plants, were infected with wolbachia bacteria. these bacteria may induce cytoplasmic incompatibility in thei ...	2000	11075704
genes for the type iv secretion system in an intracellular symbiont, wolbachia, a causative agent of various sexual alterations in arthropods.	wolbachia species are intracellular bacteria known to cause reproductive abnormalities in their hosts. in this study, we identified wolbachia genes encoding homologs to the type iv secretion system by which many pathogenic bacteria secrete macromolecules. the genes identified encoded most of the essential components of the secretion system and were cotranscribed as an operon.	2000	11053403
influential passengers come of age. 1st international wolbachia conference, orthodox academy, kolymbari, crete, greece, 7-12 june 2000.		2000	11041802
addition of wsp sequences to the wolbachia phylogenetic tree and stability of the classification.	wolbachia are symbiotic bacteria altering reproductive characters of numerous arthropods. their most recent phylogeny and classification are based on sequences of the wsp gene. we sequenced wsp gene from six wolbachia strains infecting six trichogramma species that live as egg parasitoids on many insects. this allows us to test the effect of the addition of sequences on the wolbachia phylogeny and to check the classification of wolbachia infecting trichogramma. the six wolbachia studied are clas ...	2000	11040288
tetracycline inhibits development of the infective-stage larvae of filarial nematodes in vitro.	in recent years, studies have linked tetracycline treatment of filaria-infected animals with reduced adult worm burdens and decreased levels of microfilaremia. these observations are believed to be attributable to clearance of wolbachia, intracellular rickettsial-like organisms found within filarial tissues. although maximal worm reductions were observed when treatment was initiated early in infection, it is not known whether tetracycline inhibits development of infective-stage larvae. to addres ...	2000	11038309
ultrastructural and molecular identification of a wolbachia endosymbiont in a spider, nephila clavata.	wolbachia-like bacteria were observed in the egg cells of golden orb-weaving spider, nephila clavata, by means of transmission electron microscopy. the bacteria exhibited the typical morphology of wolbachia, including three enveloping membranes. based on the amplification and sequencing of partial 16s rdna and ftsz gene, the bacteria were identified as wolbachia, intracellular, transovarially inherited alpha-proteobacteria in invertebrates. phylogenetic analysis based on 16s rdna and ftsz gene s ...	2000	11029673
male-killing wolbachia in drosophila: a temperature-sensitive trait with a threshold bacterial density.	inherited microorganisms that disturb the reproduction of their host have been characterized from a number of host taxa. to understand the general principles underlying the genetic and mechanistic basis of interactions, study of different agents in model host species is required. to this end, the nature and genetics of the maternally inherited sex-ratio trait of drosophila bifasciata were investigated. successful curing of affected lines with antibiotics demonstrated this trait was associated wi ...	2000	11014817
wolbachia segregation rate in drosophila simulans naturally bi-infected cytoplasmic lineages.	wolbachia are maternally transmitted endocellular bacteria infecting several arthropod species. in order to study wolbachia segregation rate, drosophila simulans females from an indo-pacific population (seychelles) bi-infected by the two wolbachia variants wha and wno were backcrossed to uninfected males in two conditions. in the first case, seychelles males from a stock cured from its wolbachia by tetracycline treatment were used. in the second case, the males came from a naturally uninfected t ...	2000	11012722
transinfection of wolbachia in the mediterranean flour moth, ephestia kuehniella, by embryonic microinjection.	wolbachia are maternally transmitted intracellular bacteria found in many arthropod species. they cause a reproductive incompatibility called cytoplasmic incompatibility (ci) in several hosts, including the mediterranean flour moth, ephestia kuehniella. two strains of e. kuehniella, one from yokohama city and the other from tsuchiura city, express different levels of ci: the yokohama strain expresses ci at a higher level than the tsuchiura strain. in order to determine whether the difference of ...	2000	11012714
lipopolysaccharide-like molecules derived from wolbachia endobacteria of the filaria onchocerca volvulus are candidate mediators in the sequence of inflammatory and antiinflammatory responses of human monocytes.	the majority of onchocerca volvulus-infected persons show signs of cellular anergy, and long-time survival of adult and larval parasites in subcutaneous tissue is observed. the mechanisms leading to immunological hyporesponsiveness are poorly understood. monocytes/macrophages represent a link between the innate and acquired immune system and are candidate cells to promote inflammatory and antiinflammatory processes. in the present study we have shown that products of microfilarial (o. volvulus) ...	2000	11008105
evolutionary novelties in islands: drosophila santomea, a new melanogaster sister species from são tomé.	the finding of new melanogaster sister species may help us in understanding more about how the emergence of genetic novelties, particularly in insular habitats, can result in speciation. here we report on the discovery of drosophila santomea, which is the first melanogaster sibling found off west-equatorial africa, on são tomé, one of the gulf of guinea islands. although the eight other melanogaster sister species are remarkably conservative in their morphology except for their terminalia, the n ...	2000	11007323
male-killing wolbachia in a flour beetle.	the bacteria in the genus wolbachia are cytoplasmically inherited symbionts of arthropods. infection often causes profound changes in host reproduction, enhancing bacterial transmission and spread in a population. the reproductive alterations known to result from wolbachia infection include cytoplasmic incompatibility (ci), parthenogenesis, feminization of genetic males, fecundity enhancement, male killing and, perhaps, lethality here, we report male killing in a third insect, the black flour be ...	2000	10983833
wolbachia infection frequencies in insects: evidence of a global equilibrium?	wolbachia are a group of cytoplasmically inherited bacteria that cause reproduction alterations in arthropods, including parthenogenesis, reproductive incompatibility, feminization of genetic males and male killing. previous general surveys of insects in panama and britain found wolbachia to be common, occurring in 16-22% of species. here, using similar polymerase chain reaction methods, we report that 19.3% of a sample of temperate north american insects are infected with wolbachia, a frequency ...	2000	10972121
long pcr improves wolbachia dna amplification: wsp sequences found in 76% of sixty-three arthropod species.	bacteria belonging to the genus wolbachia are associated with a variety of reproductive anomalies in arthropods. allele-specific polymerase chain reaction (= standard pcr) routinely has been used to amplify wolbachia dna from arthropods. while testing the two-spotted spider mite tetranychus urticae and other arthropods known to be infected with wolbachia, standard pcr frequently produced false negatives, perhaps because the dna from the arthropod host interfered with amplification by taq dna pol ...	2000	10971717