Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| 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 |
| wolbachia. a tale of sex and survival. | 2001 | 11352061 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| of filariasis, mice and men. | 2001 | 11394345 | |
| 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 |
| 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 |
| 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 |
| evolution. haploids--hapless or happening? | 2001 | 11431554 | |
| one in the eye for river blindness. | 2001 | 11435084 | |
| 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 |
| 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 |
| 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 |
| meet the herod bug. | 2001 | 11452274 | |
| prospects and challenges in lymphatic filariasis. | 2001 | 11472552 | |
| 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 |
| 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 |
| doxycycline and eradication of microfilaremia in patients with loiasis. | 2001 | 11485684 | |
| cytoplasmic incompatibility and maternal-haploid. | 2001 | 11485804 | |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| one in the eye for river blindness. | 2001 | 11685890 | |
| 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 |
| 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| how many wolbachia supergroups exist? | 2002 | 11861893 | |
| 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 |
| infectious disease. new culprit emerges in river blindness. | 2002 | 11884722 | |
| 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 |
| 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 |
| 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 |
| 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 |
| parasitic sex puppeteers. | 2002 | 11905109 | |
| deleterious wolbachia in the ant formica truncorum. | wolbachia is a maternally inherited bacterium that may manipulate the reproduction of its arthropod hosts. in insects, it is known to lead to inviable matings, cause asexual reproduction or kill male offspring, all to its own benefit, but to the detriment of its host. in social hymenoptera, wolbachia occurs widely, but little is known about its fitness effects. we report on a wolbachia infection in the wood ant formica truncorum, and evaluate whether it influences reproductive patterns. all 33 c ... | 2002 | 11916479 |
| wolbachia infection associated with all-female broods in hypolimnas bolina (lepidoptera: nymphalidae): evidence for horizontal transmission of a butterfly male killer. | inherited bacteria that kill male hosts during embryogenesis infect a wide range of insect species. in order to ascertain if there are patterns to host infection, with particular male killing bacteria specialising on particular taxa, we investigated the male killing trait in the butterfly hypolimnas bolina. all-female broods were first reported in this species in the 1920s. investigation of this system in the fiji islands revealed the causal agent of sex ratio distortion in h. bolina to be a mal ... | 2002 | 11920117 |
| dynamics of double and single wolbachia infections in drosophila simulans from new caledonia. | the bacterial symbiont wolbachia can cause cytoplasmic incompatibility in drosophila simulans flies: if an infected male mates with an uninfected female, or a female with a different strain of wolbachia, there can be a dramatic reduction in the number of viable eggs produced. here we explore the dynamics associated with double and single wolbachia infections in new caledonia. doubly infected females were compatible with all males in the population, explaining the high proportion of doubly infect ... | 2002 | 11920119 |
| vertical transmission of wolbachia in tetranychus kanzawai kishida and panonychus mori yokoyama (acari: tetranychidae). | the vertical transmission of wolbachia in two species of spider mite was investigated and compared. one species, tetranychus kanzawai kishida, was infected with a modification negative strain of wolbachia while the other species, panonychus mori yokoyama, was infected with a modification positive strain. the infection showed perfect maternal transmission in the laboratory population of t. kanzawai in which wolbachia-infected females produced infected offspring regardless of whether they mated wi ... | 2002 | 11920120 |
| host age effect and expression of cytoplasmic incompatibility in field populations of wolbachia-superinfected aedes albopictus. | the asian tiger mosquito, aedes albopictus (skuse), is a known vector of dengue in south america and southeast asia. it is naturally superinfected with two strains of wolbachia endosymbiont that are able to induce cytoplasmic incompatibility (ci). in this paper, we report the strength of ci expression in crosses involving field-caught males. ci expression was found to be very strong in all crosses between field males and laboratory-reared uninfected or walba infected young females. in addition, ... | 2002 | 11920134 |
| bacterial endosymbionts of onchocerca volvulus in the pathogenesis of posttreatment reactions. | treatment of onchocerciasis with diethylcarbamazine (dec) or ivermectin is associated with a posttreatment reaction characterized by fever, tachycardia, hypotension, lymphadenopathy, and pruritus. to investigate the role of the wolbachia bacterial endosymbiont of onchocerca volvulus in these reactions, serum samples collected before and after treatment with either anthelmintic were assessed for evidence of wolbachia dna. by use of real-time quantitative polymerase chain reaction, wolbachia dna w ... | 2002 | 11920298 |
| the brugia malayi genome project: expressed sequence tags and gene discovery. | to advance and facilitate molecular studies of brugia malayi, one of the causative agents of human lymphatic filariasis, an expressed sequence tag (est)-based gene discovery programme has been carried out. over 22,000 ests have been produced and deposited in the public databases by a consortium of laboratories from endemic and non-endemic countries. the ests have been analysed using custom informatic tools to reveal patterns of individual gene expression that may point to potential targets for f ... | 2002 | 11925998 |
| human onchocerciasis: the essential partnership between research and disease control efforts. | twenty years ago onchocerciasis was a disease generally ignored by the medical world, except by those who actually worked with the affected people in africa and latin america. now, largely as a result of the success of mass vector control and drug treatment programs, this is a disease management model for developing countries. the recent literature on onchocerciasis has, not surprisingly, mainly focused on various aspects of control. investigation into the more basic questions is needed to ensur ... | 2000 | 11964814 |
| lymphatic filariasis: new insights and prospects for control. | although lymphatic filariasis remains among the major causes of disability among the tropical infectious diseases, dramatic advances have been made in the approach to its diagnosis, epidemiology and treatment, in our understanding of the molecular composition of the parasites that cause these infections, and in the factors underlying the pathology seen. superimposing the tools of modern epidemiology, immunology, and molecular biology on field-based clinical trials has allowed the emergence of th ... | 2001 | 11964873 |
| a new approach to the treatment of filariasis. | the symbiosis of filarial nematodes and intracellular wolbachia bacteria has recently been exploited as a target for antibiotic therapy of filariasis. antibiotic treatment of filarial nematodes results in sterility and inhibits larval development and adult worm viability. in the first trial on human onchocerciasis depletion of bacteria following treatment with doxycycline resulted in a complete and long-term block of embryogenesis. bacteria are unable to repopulate nematode tissues up to 18 mont ... | 2001 | 11964892 |
| wolbachia dna recognition. | 2002 | 11965304 | |
| 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 |
| electron microscopic and molecular identification of wolbachia endosymbionts from onchocerca lupi: implications for therapy. | it was recently demonstrated that wolbachia intracellular bacteria (alpha 2 proteobacteria, rickettsiales) living in filarial nematodes are obligatory symbionts of their hosts. herein, we report the electron microscopic and 16s ribosomal dna-based (16s rdna) identification of the endobacteria harboring in onchocerca lupi. the worm nodules containing the nematodes were removed from three hungarian dogs naturally infected with o. lupi. wolbachia-like endobacteria were detected by electron microsco ... | 2002 | 11992713 |
| evolutionary biology. timing is everything for wolbachia hosts. | 2002 | 12004092 | |
| role of delayed nuclear envelope breakdown and mitosis in wolbachia-induced cytoplasmic incompatibility. | the bacterium wolbachia manipulates reproduction in millions of insects worldwide; the most common effect is cytoplasmic incompatibility (ci). we found that ci resulted from delayed nuclear envelope breakdown of the male pronucleus in nasonia vitripennis. this caused asynchrony between the male and female pronuclei and, ultimately, loss of paternal chromosomes at the first mitosis. when wolbachia were present in the egg, synchrony was restored, which explains suppression of ci in these crosses. ... | 2002 | 12004132 |
| how does infection with parthenogenesis-inducing wolbachia reduce the fitness of trichogramma? | we analyzed the survival rate of the immature stages of trichogramma species and lines that differed in their mode of reproduction. specifically, we compared the mortality of arrhenotokous (w(-)), irrevertable thelytokous (w(-)), and wolbachia-associated thelytokous (w(+)) forms. the embryonic mortality of the w(+) strains was significantly higher than that of the w(-) lines. the embryonic mortality was negligible for the arrhenotokous trichogramma evanescens and the thelytokous trichogramma cac ... | 2001 | 12009809 |
| good news on a tropical disease. | 2002 | 12029099 | |
| a new insight into the pathogenesis of filarial disease. | filariasis is a major public health problem throughout many regions of the tropics. the disease is caused by several species of filarial nematode including wuchereria bancrofti and brugia malayi, the agents of lymphatic filariasis, and onchocerca volvulus, the cause of 'riverblindness'. disease caused by these worms varies depending on the tissue location of the parasite, and is associated with episodes of acute and chronic inflammation. these pathologies, including elephantiasis and blindness, ... | 2002 | 12041732 |
| spatially explicit models of turelli-hoffmann wolbachia invasive wave fronts. | this paper examines different mathematical models of insect dispersal and infection spread and compares these with field data. reaction-diffusion and integro-difference equation models are used to model the spatio-temporal spread of wolbachia in drosophila simulans populations. the models include cytoplasmic incompatibility between infected females and uninfected males that creates a threshold density, similar to an allee effect, preventing increase from low incidence of infection in the host po ... | 2002 | 12051989 |
| feminization of genetic males by a symbiotic bacterium in a butterfly, eurema hecabe (lepidoptera: pieridae). | wolbachia are symbiotic bacteria found in many arthropods and filarian nematodes. they often manipulate the reproduction of host arthropods. in the present study, female-biased sex-ratio distortion in the butterfly eurema hecabe was investigated. breeding experiments showed that this distorted sex ratio is maternally inherited. when treated with tetracycline, adult females of the thelygenic line produced male progeny only. after pcr using wolbachia-specific primers for the ftsz gene a positive r ... | 2002 | 12061400 |
| tracking down the culprit in river blindness. | 2002 | 12062980 | |
| could antibiotics cure river blindness? | 2002 | 12075374 | |
| high wolbachia density in insecticide-resistant mosquitoes. | wolbachia symbionts are responsible for various alterations in host reproduction. the effects of the host genome on endosymbiont levels have often been suggested, but rarely described. here, we show that wolbachia density is strongly modified by the presence of insecticide-resistant genes in the common house mosquito, culex pipiens. the wolbachia density was estimated using a real-time quantitative pcr assay. strains harbouring different genes conferring resistance were more infected than a susc ... | 2002 | 12079666 |
| antibiotics for the treatment of onchocerciasis and other filarial infections. | more effective drugs are needed for the treatment of human filarial diseases and the elimination of these infections as a public health problem. the drugs must either kill or sterilize adult worms. the relevant filariae, onchocerca volvulus, wuchereria bancofti and brugia species, harbor rickettsial endoboacteria of the genus wolbachia as symbionts. animal experiments have shown that the elimination of these endobacteria causes inhibition of embryogenesis, and with onchocerca ochengi a macrofila ... | 2002 | 12090719 |
| bacteria in ovarioles of females from maleless families of ladybird beetles adalia bipunctata l. (coleoptera: coccinellidae) naturally infected with rickettsia, wolbachia, and spiroplasma. | ovarioles were found to be infected with spiroplasma, wolbachia, and rickettsia in adalia bipunctata females with maleless progeny in different natural populations. ooplasm was infected with few wolbachia bacteria. in ooplasm infected by rickettsia, bacteria were present in small foci. spiroplasmas were found encapsulated into ooplasm from the wider intercellular spaces between epithelial and oocyte cells. the cytoplasm of follicular epithelia infected with rickettsia was heavily destroyed, but ... | 2002 | 12095235 |
| presence of wolbachia endosymbionts in different silkworm species and races and in their uzi fly parasites. | 2002 | 12095241 | |
| a host parasite interaction rescues drosophila oogenesis defects. | the cytoplasmically inherited bacterium wolbachia pipientis is a widespread parasite of arthropods that manipulates the reproductive biology of its hosts, often to their detriment, in order to foster its own transmission through egg cytoplasm. here we report that infection by wolbachia restores fertility to drosophila melanogaster mutant females prevented from making eggs by protein-coding lesions in sex-lethal (sxl), the master regulator of sex determination. suppression of sterility by wolbach ... | 2002 | 12097909 |
| in vitro effects of antibiotics on brugia malayi worm survival and reproduction. | recent studies have suggested that intracellular wolbachia spp. endobacteria are necessary for the reproduction and survival of filarial nematodes. the effects of antibiotics that are active against related bacteria on adult worms and microfilariae (mf) of brugia malayi in vitro were investigated. antibiotics tested were doxycycline (doxy), tetracycline (tet), rifampicin (rif), azithromycin (azith), and chloramphenicol (chlor). doxy, tet, rif, and azith reduced release of mf by adult female worm ... | 2002 | 12099435 |
| [river blindness: not only the work of onchocerca volvulus?]. | 2002 | 12102035 | |
| [combatting river blindness by means of chemotherapy directed at the symbiotic wolbachia bacteria in the causative filariae]. | in a mouse model of river blindness it was demonstrated that wolbachia bacteria, endosymbionts of filarial nematodes, play an important role in the inflammatory process leading to the disease and that this process depends on toll-like receptor 4. wolbachia is found in many arthropods and in all filariae pathogenic for man. treatment with doxycycline depletes female filariae of wolbachia and renders them infertile for at least 18 months. chemotherapy of filarial nematodes should be studied for th ... | 2002 | 12132134 |
| maternal transmission efficiency of wolbachia superinfections in aedes albopictus populations in thailand. | we examined the transmission efficiency of 2 strains of wolbachia bacteria that cause cytoplasmic incompatibility in field populations of aedes albopictus by polymerase chain reaction assay. we found mainland and island populations throughout thailand to be superinfected with group a and b bacteria. of 320 wolbachia-positive adult mosquitoes, 97.5% were infected with both groups. single infected individuals of each wolbachia group were encountered in nearly equal numbers. we screened 550 offspri ... | 2002 | 12135258 |
| 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 |
| 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 |
| 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 |
| on the evolution of cytoplasmic incompatibility in haplodiploid species. | the most enigmatic sexual manipulation by wolbachia endosymbionts is cytoplasmic incompatibility (ci): infected males are reproductively incompatible with uninfected females. in this paper, we extend the theory on population dynamics and evolution of ci, with emphasis on haplodiploid species. first, we focus on the problem of the threshold to invasion of the wolbachia infection in a population. simulations of the dynamics of infection in small populations show that it does not suffice to assume ... | 2002 | 12144012 |
| searching for wolbachia (rickettsiales: rickettsiaceae) in mosquitoes (diptera: culicidae): large polymerase chain reaction survey and new identifications. | bacteria of the genus wolbachia constitute a group of intracellular and maternally inherited micro-organisms that are widespread in arthropods, inducing several reproductive disorders such as cytoplasmic incompatibility in their hosts. considering relevant biological implications related to the presence of wolbachia in several insect orders, for example its potential role as mechanism for rapid speciation and as vehicle to drive genetic markers in wild populations of vectors of medical and veter ... | 2002 | 12144285 |
| 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 |
| internal spatiotemporal population dynamics of infection with three wolbachia strains in the adzuki bean beetle, callosobruchus chinensis (coleoptera: bruchidae). | the adzuki bean beetle, callosobruchus chinensis, is infected with three distinct lineages of endosymbiotic bacteria belonging to the genus wolbachia, which were designated wbrucon, wbruori, and wbruaus. in an attempt to understand the mechanisms underlying the infection with these three organisms, the spatiotemporal infection dynamics of the three wolbachia strains was investigated in detail by using a quantitative pcr technique. during the development of c. chinensis, the wbrucon, wbruori, and ... | 2002 | 12147509 |