Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| real-time pcr for quantification of the bacterial endosymbionts (wolbachia) of filarial nematodes. | filarial nematodes harbour intracellular symbiotic bacteria belonging to the genus wolbachia. wolbachia is thought to play an important role in the biology of the nematode. moreover, wolbachia appears to be involved in the immunopathogenesis of filariasis and in the onset of the side-effects of antifilarial therapy. investigations in these research areas require reliable methods to quantify wolbachia both in nematodes and in vertebrate tissues. to this purpose, we designed a quantitative real-ti ... | 2001 | 12402526 |
| 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 |
| one in the eye for river blindness. | 2001 | 11435084 | |
| of filariasis, mice and men. | 2001 | 11394345 | |
| 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 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 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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-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 | |
| prospects and challenges in lymphatic filariasis. | 2001 | 11472552 | |
| 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 |
| infectious speciation. | 2001 | 11217844 | |
| 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 |
| evolution. nota bene. wolbachia and wasp evolution. | 2001 | 11253199 | |
| 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-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 |
| evolution. haploids--hapless or happening? | 2001 | 11431554 | |
| 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 |
| cytoplasmic incompatibility and maternal-haploid. | 2001 | 11485804 | |
| meet the herod bug. | 2001 | 11452274 | |
| 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-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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| doxycycline and eradication of microfilaremia in patients with loiasis. | 2001 | 11485684 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| wolbachia. a tale of sex and survival. | 2001 | 11352061 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 | |
| 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 |
| 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 |
| 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 |
| 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 |
| use of tetracycline in larval diet to study the effect of wolbachia on host fecundity and clarify taxonomic status of trichogramma species in cured bisexual lines. | endosymbionts of the genus wolbachia were efficiently cured from trichogramma species by incorporating 0.02% tetracycline into the artificial diet used to rear larvae. use of this technique yielded stable cured lines (bisexual and arrhenotokous lines) in which no wolbachia organisms were detected by pcr for up to 14 generations after curing. four cured strains of trichogramma pretiosum showed a significantly lower total fecundity compared to their wolbachia-infected counterpart. however, the fec ... | 2002 | 12234537 |
| influence of antibiotics on the offspring production of the wolbachia-infected parthenogenetic parasitoid encarsia formosa. | three different concentrations of the antibiotic tetracycline in honey were tested for their influence on the offspring production and longevity of the parasitoid wasp encarsia formosa. several earlier publications did not provide a conclusive answer on the effect that the wolbachia have on these wasps. the results of our experiments show that at high tetracycline hydrochloride concentrations in honey (50mg/ml) the antibiotic is toxic to the females, all females died within three days after the ... | 2002 | 12234541 |
| 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 |
| 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 |
| 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 |
| 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 |
| [river blindness: not only the work of onchocerca volvulus?]. | 2002 | 12102035 | |
| in vitro cultivation of wolbachia in insect and mammalian cell lines. | wolbachia infecting the small brown planthopper, laodelphax striatellus, were successfully maintained and cultivated in two insect and one mammalian cell lines. the bacteria with the planthopper ovary were introduced into the flasks with the cultures of the cell lines. the wolbachia proliferated in mosquito (aedes albopictus) and lepidopteran (heliothis zea) cell lines and in the mouse cell line, l929. proliferation of wolbachia was confirmed by electron microscopy and quantitative polymerase ch ... | 2002 | 12534342 |
| the filarial endosymbiont wolbachia sp. is absent from setaria equina. | wolbachia sp. was first reported in filarial nematodes over 25 yr ago. today, much research is focused on the role of these bacteria in filarial worm biology. the filarial symbionts are closely related to arthropod symbionts, which are known to modify host reproduction and biology through various mechanisms. similarly, it has been suggested that wolbachia sp. is essential for long-term survival and reproduction of filariae. we report that wolbachia sp. 16s rdna was not found in the equine filari ... | 2002 | 12537121 |
| diversity and geographic distribution of secondary endosymbiotic bacteria in natural populations of the pea aphid, acyrthosiphon pisum. | in addition to the essential intracellular symbiotic bacterium buchnera, several facultative endosymbiotic bacteria called collectively secondary symbionts (s-symbionts) have been identified from the pea aphid acyrthosiphon pisum. we conducted an extensive and systematic survey of s-symbionts in japanese local populations of a. pisum using a specific pcr detection technique. five s-symbionts of a. pisum, pass, paus, pabs, rickettsia and spiroplasma, and two facultative endosymbionts universally ... | 2002 | 12296954 |
| [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 |
| 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 |
| 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 |
| feminizing wolbachia in an insect, ostrinia furnacalis (lepidoptera: crambidae). | wolbachia, which forms a group of maternally inherited bacteria in arthropods, often cause reproduction alterations in their hosts, such as cytoplasmic incompatibility, parthenogenesis, male-killing, hybrid breakdown and feminization. to date, wolbachia-induced feminization has been reported only in isopods. here we report that a wolbachia strain feminizes an insect host, ostrinia furnacalis. among 79 wild females of o. furnacalis examined, wolbachia infection was detected in 13 females. twelve ... | 2002 | 12180086 |
| two novel strains of wolbachia coexisting in both species of mulberry leafhoppers. | wolbachia is an intracellular symbiont that causes reproductive disorders in many insects. its presence in the leafhoppers hishimonoides sellatiformis and hishimonus sellatus, vectors of mulberry dwarf-phytoplasma, was confirmed by the pcr analysis of 16s rdna, ftsz and wsp. sequencing of cloned pcr products revealed that two wolbachia strains coexist in both leafhoppers. the phylogenetic analysis of wsp revealed that these strains belong in novel positions in the b-group of wolbachia. these str ... | 2002 | 12421415 |
| the distribution of wolbachia in fig wasps: correlations with host phylogeny, ecology and population structure. | we surveyed for the presence and identity of wolbachia in 44 species of chalcid wasps associated with 18 species of panamanian figs. we used existing detailed knowledge of the population structures of the host wasps, as well as the ecological and evolutionary relationships among them, to explore the relevance of each of these factors to wolbachia prevalence and mode of transmission. fifty-nine per cent of these wasp species have wolbachia infections, the highest proportion reported for any group ... | 2002 | 12427319 |
| 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 |
| interspecific transfer of wolbachia between two lepidopteran insects expressing cytoplasmic incompatibility: a wolbachia variant naturally infecting cadra cautella causes male killing in ephestia kuehniella. | wolbachia is known as the causative agent of various reproductive alterations in arthropods. the almond moth cadra cautella is doubly infected with a- and b-group wolbachia and expresses complete cytoplasmic incompatibility (ci). the mediterranean flour moth ephestia kuehniella carries a-group wolbachia and expresses partial ci. in the present study, the wolbachia in c. cautella was transferred to e. kuehniella from which the original wolbachia had been removed. we obtained transfected lines of ... | 2002 | 12454075 |
| wolbachia infections and superinfections in cytoplasmically incompatible populations of the european cherry fruit fly rhagoletis cerasi (diptera, tephritidae). | wolbachia is an obligately intracellular, maternally inherited bacterium which has been detected in many arthropods. wolbachia infections disperse in host populations by mechanisms such as cytoplasmic incompatibility (ci). ci leads to embryonic mortality which occurs when infected males mate with uninfected females or females with a different wolbachia strain. populations of the european cherry fruit fly rhagoletis cerasi (diptera, tephritidae) were found to be infected by two different wolbachi ... | 2002 | 12406252 |
| immunomodulatory properties of cystatins. | cystatins are natural tight-binding reversible inhibitors of cysteine proteases. because these cysteine proteases exist in all living organisms and because they are involved in various biological and pathological processes, the control of these protease functions by cystatins is of cardinal importance. cystatins are found in mammals but cystatin-like molecules are also present in mammals and parasites. in the immune system, cystatins modulate cathepsin activities and antigen presentation. they a ... | 2002 | 12440772 |
| cloning and characterization of a gene encoding glutathione-regulated potassium-efflux system protein kefkl from the endosymbiont wolbachia. | the maternally inherited intracellular symbiont wolbachia is well known for inducing a variety of reproductive and developmental abnormalities in the diverse arthropod hosts it infects. it has been implicated in causing cytoplasmic incompatibility (ci), parthenogenesis, feminization of genetic males and male killing in different hosts. however, the molecular mechanisms by which this fastidious bacterium causes these abnormalities have not yet been determined. in our study, representational diffe ... | 2002 | 12652910 |
| wolbachia interactions that determine drosophila melanogaster survival. | we have recently described a mutualistic symbiosis in which wolbachia bacteria were shown to improve the fitness of some drosophila melanogaster stocks. wolbachia did not extend longevity in all drosophila genotypes, even though 16s rdna sequences indicated that our drosophila stocks were infected with the same wolbachia strain. here, we use reciprocal hybrid crosses between two drosophila strains, one that lived longer with wolbachia (z53) and one that did not (z2), to investigate the inheritan ... | 2002 | 12449484 |
| different rates of nucleotide substitutions in wolbachia endosymbionts of arthropods and nematodes: arms race or host shifts? | the genus wolbachia encompasses intracellular bacteria found in arthropods and in filarial nematodes. in arthropods, wolbachia is primarily a reproductive parasite and shows relatively frequent horizontal transfer between host species, while in nematodes it appears to be a mutualist and is strictly vertically transmitted. we can expect that different selective pressures are acting on their genomes. here we present an analysis of three wolbachia genes, wsp, ftsz and dnaa. in wsp of arthropod wolb ... | 2002 | 12701381 |
| 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 |