Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| tissue tropism, transmission and expression of foreign genes in vivo in midgut symbionts of tsetse flies. | tsetse flies (diptera: glossinidae) harbour three different symbiotic organisms in addition to the pathogenic african trypanosomes they transmit. the two gut-associated symbionts (primary, p; secondary, s) are enteric and are nutritionally required, whereas the third microorganism wolbachia (family rickettsiaceae) affects the reproductive biology of the insects it infects. the bacteriome-associated p-symbiont (wigglesworthia glossinidia) displays a concordant phylogeny with its host tsetse speci ... | 1999 | 9927181 |
| spacer 2 region and 5s rdna variation of wolbachia strains involved in cytoplasmic incompatibility or sex-ratio distortion in arthropods. | bacteria in the genus wolbachia are widespread in arthropods and can induce sex-ratio distortion or cytoplasmic incompatibility in their hosts. the phylogeny of wolbachia has been studied using 16s rdna and the cell cycle gene ftsz, but sequence variation of those genes is limited. the spacer 2 region (sr2) was amplified to determine whether this region would improve phylogenetic resolution. the sr2 of wolbachia is 66 bp long, shows higher variation than ftsz and has very low homology with close ... | 1999 | 10030026 |
| 16s rdna phylogeny and ultrastructural characterization of wolbachia intracellular bacteria of the filarial nematodes brugia malayi, b. pahangi, and wuchereria bancrofti. | 1999 | 10092480 | |
| cross-order transfer of wolbachia from muscidifurax uniraptor (hymenoptera: pteromalidae) to drosophila simulans (diptera: drosophilidae). | bacteria of the genus wolbachia are widespread in arthropods and can induce different effects on the host such as cytoplasmic incompatibility (ci), thelytoky (t) or feminization (f). in some wolbachia-infected hosts, no effect (n) has been found. successful transfer of wolbachia by microinjection from one host to an uninfected one has been established with ci, f, n-wolbachia but not with t-wolbachia. in this paper a transfer experiment of t-wolbachia from the parasitoid muscidifurax uniraptor to ... | 1999 | 10098265 |
| wolbachia infections are distributed throughout insect somatic and germ line tissues. | wolbachia are intracellular microorganisms that form maternally-inherited infections within numerous arthropod species. these bacteria have drawn much attention, due in part to the reproductive alterations that they induce in their hosts including cytoplasmic incompatibility (ci), feminization and parthenogenesis. although wolbachia's presence within insect reproductive tissues has been well described, relatively few studies have examined the extent to which wolbachia infects other tissues. we h ... | 1999 | 10196738 |
| horizontal transfer of wolbachia between phylogenetically distant insect species by a naturally occurring mechanism. | wolbachia is a genus of alpha-proteobacteria found in obligate intracellular association with a wide variety of arthropods, including an estimated 10-20% of all insect species [1]. wolbachia represents one of a number of recently identified 'reproductive parasites' [2] which manipulate the reproduction of their hosts in ways that enhance their own transmission [3] [4] [5] [6] [7] [8] [9]. the influence of wolbachia infection on the dynamics of host populations has focused considerable interest o ... | 1999 | 10209097 |
| effects of tetracycline on the filarial worms brugia pahangi and dirofilaria immitis and their bacterial endosymbionts wolbachia. | wolbachia endosymbiotic bacteria have been shown to be widespread among filarial worms and could thus play some role in the biology of these nematodes. indeed, tetracycline has been shown to inhibit both the development of adult worms from third-stage larvae and the development of the microfilaraemia in jirds infected with brugia pahangi. the possibility that these effects are related to the bacteriostatic activity of tetracycline on wolbachia symbionts should be considered. here we show that te ... | 1999 | 10221636 |
| four intracellular genomes direct weevil biology: nuclear, mitochondrial, principal endosymbiont, and wolbachia. | cell physiology in the weevil sitophilus oryzae is coordinated by three integrated genomes: nuclear, mitochondrial, and the "s. oryzae principal endosymbiont" (sope). sope, a cytoplasmic bacterium (2 x 10(3) bacteria per specialized bacteriocyte cell and 3 x 10(6) bacteria per weevil) that belongs to the proteobacteria gamma3-subgroup, is present in all weevils studied. we discovered a fourth prokaryotic genome in somatic and germ tissues of 57% of weevil strains of three species, s. oryzae, sit ... | 1999 | 10359795 |
| preliminary results on the effect of tetracycline on the embryogenesis and symbiotic bacteria (wolbachia) of dirofilaria immitis. an update and discussion. | the distribution and phylogeny of wolbachia in filarial species suggests that these endosymbiotic bacteria may be important in the biology of their filarial hosts. an experiment to falsify this hypothesis would be to treat filarial worms with antibiotics which are active against intracellular bacteria. indeed, it has already been shown that tetracycline treatment inhibits development in a model filarial species (brugia pahangi) at different stages of the life cycle, in both mosquito and mammalia ... | 1998 | 10376278 |
| distribution and phylogeny of wolbachia inducing thelytoky in rhoditini and 'aylacini' (hymenoptera: cynipidae). | wolbachia are endosymbiotic bacteria responsible for thelytoky in several parasitoid hymenopteran genera. after finding these micro-organisms in some populations of diplolepis spinosissimae (hymenoptera: cynipidae) where they are responsible for thelytoky through gamete duplication, we searched for wolbachia spp. using specific pcr primers in nineteen other species of the rhoditini tribe (rose gallwasps) and eight species of the 'aylacini' tribe (gallwasps associated with herbaceous plants). wol ... | 1999 | 10380102 |
| microbe-induced cytoplasmic incompatibility as a mechanism for introducing transgenes into arthropod populations. | many arthropods are infected with maternally transmitted, intracellular bacteria of the genus wolbachia. these infections often produce 'cytoplasmic incompatibility' (ci)--reduced egg-hatch frequencies when uninfected females mate with infected males or when males and females carrying different wolbachia strains mate. because infected females often enjoy a fitness advantage--they are effectively immune to any effects from males carrying the same wolbachia strain--wolbachia and associated cytopla ... | 1999 | 10380108 |
| a stable triple wolbachia infection in drosophila with nearly additive incompatibility effects. | drosophila simulans strains infected with three different wolbachia strains were generated by experimental injection of a third symbiont into a naturally double-infected strain. this transfer led to a substantial increase in total wolbachia density in the host strain. each of the three symbionts was stably transmitted in the presence of the other two. triple-infected males were incompatible with double-infected females. no evidence was obtained for interference between modification effects of th ... | 1999 | 10383683 |
| evolution of wolbachia pipientis transmission dynamics in insects. | wolbachia pipientis is an intracellular bacterial parasite of arthropods that enhances its transmission by manipulating host reproduction, most commonly by inducing cytoplasmic incompatibility. the discovery of isolates with modified cytoplasmic incompatibility phenotypes and others with novel virulence properties is an indication of the potential breadth of evolutionary strategies employed by wolbachia. | 1999 | 10390640 |
| the structure of a glycosylated protein hormone responsible for sex determination in the isopod, armadillidium vulgare. | two glycoforms (ah1 and ah2) of androgenic hormone, and its corresponding hormone precursor derived from hplc-purified androgenic gland extract from the woodlouse armadillidium vulgare were fully characterized by microsequencing and mass spectrometry. the amino-acid sequences of the two glycoforms were identical; they consist of two peptide chains, a and b, of 29 and 44 amino acids, respectively, with chain a carrying one n-glycosylated moiety on asn18. the two chains are linked by two disulfide ... | 1999 | 10411634 |
| the first detection of the insertion sequence isw1 in the intracellular reproductive parasite wolbachia. | wolbachia are maternally inherited intracellular rickettsia-like bacteria known to infect a wide range of arthropods. they are associated with a number of different reproductive phenotypes in their hosts, such as cytoplasmic incompatibility, parthenogenesis, and feminization. we report on a novel insertion sequence (is), isw1, which was identified in the region downstream of groel of a wolbachia strain, wtai. the 573-bp-long isw1 sequence is the first is element observed in this organism, displa ... | 1999 | 10413661 |
| gene organization of the dnaa region of wolbachia. | the dnaa region of wolbachia, an intracellular bacterial parasite of insects, is unique. a glna cognate was found upstream of the dnaa gene, while neither of the two open reading frames detected downstream of dnaa has any homologue in the database. this unusual gene arrangement may reflect requirements associated with the unique ecological niche this agent occupies. | 1999 | 10419978 |
| mitochondrial dna polymorphism, sex ratio distorters and population genetics in the isopod armadillidium vulgare. | two maternally inherited sex ratio distorters (srd) impose female-biased sex ratios on the wood louse armadillidium vulgare by feminizing putative males. these srd are (i) an intracytoplasmic bacterium of the genus wolbachia, and (ii) another non-mendelian element of unknown nature: the f element. mitochondrial dna variation was investigated in a. vulgare field populations to trace the evolution of host-srd relationships and to investigate the effect of srd on host cytoplasmic polymorphism. the ... | 1999 | 10430591 |
| mitochondrial dna variability and wolbachia infection in two sibling woodlice species | several morphological races and subspecies have been described and later included within the terrestrial isopod species porcellionides pruinosus. during our study of this species, we have worked on specimens from france, greece, tunisia and reunion island. laboratory crosses have revealed two separate groups of populations: french populations (four localities) in one group, and those from tunisia, reunion island and greece in the other. french individuals were reproductively isolated from those ... | 1999 | 10447705 |
| phylogeny of the arthropod endosymbiont wolbachia based on the wsp gene. | bacteria of the genus wolbachia (rickettsiae) are widespread in arthropods and can induce cytoplasmic incompatibility (ci), thelytoky (t) or feminization (f) in their host. recent research on the wsp gene of mainly ci inducing wolbachia has shown that this gene evolves at a much faster rate than previously sequenced genes such as 16s or ftsz. as a result this gene appears to be very useful in subdividing the wolbachia and twelve groups have been distinguished to date. here we extend the wolbachi ... | 1999 | 10469257 |
| wolbachia genomes and the many faces of symbiosis. | 1999 | 10511680 | |
| wolbachia bacteria of filarial nematodes. | the finding that the intracellular bacteria of filarial nematodes are related to the wolbachia symbionts of arthropods has generated great interest. here, mark taylor and achim hoerauf review recent studies by several groups on the structure, distribution and phylogeny of these endosymbionts, and discuss the potential role for these bacteria in filarial disease and as a target for chemotherapy. | 1999 | 10511685 |
| wolbachia pipientis: microbial manipulator of arthropod reproduction. | the alpha-proteobacterium wolbachia pipientis is a very common cytoplasmic symbiont of insects, crustaceans, mites, and filarial nematodes. to enhance its transmission, w. pipientis has evolved a large scale of host manipulations: parthenogenesis induction, feminization, and male killing. w. pipientis's most common effect is a crossing incompatibility between infected males and uninfected females. little is known about the genetics and biochemistry of these symbionts because of their fastidious ... | 1999 | 10547686 |
| sequence evolution in bacterial endosymbionts having extreme base compositions. | a major limitation on ability to reconstruct bacterial evolution is the lack of dated ancestors that might be used to evaluate and calibrate molecular clocks. vertically transmitted symbionts that have cospeciated with animal hosts offer a firm basis for calibrating sequence evolution in bacteria, since fossils of the hosts can be used to date divergence events. sequences for a functionally diverse set of genes have been obtained for bacterial endosymbionts (buchnera) from two pairs of aphid hos ... | 1999 | 10555290 |
| phylogenetic analysis of the 16s rdna of the cytoplasmic bacterium wolbachia from the novel host folsomia candida (hexapoda, collembola) and its implications for wolbachial taxonomy. | wolbachia pipientis are intracellular, transovarially inherited alpha-proteobacteria in invertebrates. four major wolbachia groups exist: a, b (contained in divergent arthropods), c and d (harbored by nematoda). by means of transmission electron microscopy, we observed wolbachia-like bacteria in a primitive insect, folsomia candida (hexapoda, collembola, isotomidae). 16s rdna analysis proved them to constitute a novel lineage, henceforth named group e, in the wolbachial phylogenetic tree. it sha ... | 1999 | 10556723 |
| wolbachia infection in the terrestrial isopod oniscus asellus: sex ratio distortion and effect on fecundity | maternally inherited wolbachia bacteria are widespread in arthropods where they are responsible for various reproductive alterations. in terrestrial isopods (woodlice), wolbachia may induce feminization or cytoplasmic incompatibility (ci), but their effect remains unknown in most host species. to increase our understanding of host/symbiont interactions in terrestrial isopods, the effect of wolbachia was investigated in the oniscidean oniscus asellus, mainly to discriminate between feminization a ... | 1999 | 10583549 |
| wolbachia: why these bacteria are important to genome research. | 1999 | 10587942 | |
| the wolbachia genome consortium. | 1999 | 10587943 | |
| germ cells colonized by endosymbiotic bacteria. | 1999 | 10591206 | |
| phylogenetic evidence for horizontal transmission of wolbachia in host-parasitoid associations. | endosymbiotic wolbachia infect a number of arthropod species in which they can affect the reproductive system. while maternally transmitted, unlike mitochondria their molecular phylogeny does not parallel that of their hosts. this strongly suggests horizontal transmission among species, the mechanisms of which remain unknown. such transfers require intimate between-species relationships, and thus host-parasite associations are outstandingly appropriate for study. here, we demonstrate that hymeno ... | 1999 | 10605113 |
| frequency of wolbachia infection in laboratory and field sand fly (diptera: psychodidae) populations. | using a polymerase chain reaction (pcr) assay with primers designed for the wolbachia 16s rrna and outer surface protein (wsp) gene, we screened 11 laboratory colonies and 4 field samples of 6 sand fly species for wolbachia infection. infection was only detected in 3 laboratory colonies of phlebotomus papatasi scopoli, originally collected in israel, egypt, and saudi arabia. | 1999 | 10612622 |
| acetone preservation: a practical technique for molecular analysis. | in attempts to establish a convenient and reliable method for field collection and archival preservation of insects and their endosymbiotic microorganisms for molecular analysis, acetone, ethanol, and other organic solvents were tested for dna preservability of the pea aphid acyrthosiphon pisum and its intracellular symbiotic bacterium buchnera sp. after 6 months' storage, not only the band of high-molecular-size dna but also the bands of rrna were well preserved in acetone, ethanol, 2-propanol, ... | 1999 | 10620236 |
| molecular evidence for multiple infections of a new subgroup of wolbachia in the european raspberry beetle byturus tomentosus. | wolbachia, a group of maternally inherited intracellular parasitic bacteria, alter host reproduction, including the induction of thelytokous parthenogenesis, feminization of genetic males, son killing and, most commonly, the induction of cytoplasmic incompatibility (ci), in a diverse array of arthropods. ci can result in infertility and has attracted attention because of its potential in biological control and as an agent in speciation. although there has been some analysis of overall infection ... | 2000 | 10652077 |
| wolbachia as a speciation agent. | 2000 | 10652551 | |
| a genetic test of the mechanism of wolbachia-induced cytoplasmic incompatibility in drosophila. | cytoplasmic bacteria of the genus wolbachia are best known as the cause of cytoplasmic incompatibility (ci): many uninfected eggs fertilized by wolbachia-modified sperm from infected males die as embryos. in contrast, eggs of infected females rescue modified sperm and develop normally. although wolbachia cause ci in at least five insect orders, the mechanism of ci remains poorly understood. here i test whether the target of wolbachia-induced sperm modification is the male pronucleus (e.g., dna o ... | 2000 | 10655228 |
| high temperatures eliminate wolbachia, a cytoplasmic incompatibility inducing endosymbiont, from the two-spotted spider mite. | wolbachia can induce cytoplasmic incompatibility (ci) in the arrhenotokous two-spotted spider mite between uninfected females and infected males. cytoplasmic incompatibility is expressed through a male-biased sex ratio and a low hatchability, and can be suppressed by removing wolbachia from spider mites reared on a diet with antibiotics. here we investigated whether heat-treatment can elimate wolbachia from infected mites. using a pcr assay with a wolbachia-specific primer pair (ftsz), and by st ... | 1999 | 10668862 |
| sex-ratio-distorting wolbachia causes sex-role reversal in its butterfly host. | sex-role-reversed mating systems in which females compete for males and males may be choosy are usually associated with males investing more than females in offspring. we report that sex-role reversal may also be caused by selfish genetic elements which distort the sex ratio towards females. some populations of the butterflies acraea encedon and acraea encedana are extremely female biased because over 90% of females are infected with a wolbachia bacterium that is maternally inherited and kills m ... | 2000 | 10670955 |
| do wolbachia influence fecundity in nasonia vitripennis? | this paper reports the influence of a vertically transmitted symbiont, wolbachia, on host fitness in the parasitic wasp, nasonia vitripennis. we measured fecundities of uninfected strains and strains infected with either two wolbachia variants (wav,wbv) or one (wav or wbv). preliminary tests suggested that double-infected females produce more offspring on average than uninfected females. however, further studies failed to yield consistent fitness effects. to control for host genetic effects, the ... | 2000 | 10692011 |
| the filarial genome project: analysis of the nuclear, mitochondrial and endosymbiont genomes of brugia malayi. | the filarial genome project (fgp) was initiated in 1994 under the auspices of the world health organisation. brugia malayi was chosen as the model organism due to the availability of all life cycle stages for the construction of cdna libraries. to date, over 20000 cdna clones have been partially sequenced and submitted to the est database (dbest). these ests define approximately 7000 new brugia genes. analysis of the est dataset provides useful information on the expression pattern of the most a ... | 2000 | 10731564 |
| the genomes of onchocerca volvulus. | onchocerca volvulus, the filarial parasite that causes onchocerciasis or river blindness, contains three distinct genomes. these include the nuclear genome, the mitochondrial genome and the genome of an intracellular endosymbiont of the genus wolbachia. the nuclear genome is roughly 1.5x10(8) bp in size, and is arranged on four chromosome pairs. analysis of expressed sequence tags from different life-cycle stages has resulted in the identification of transcripts from roughly 4000 o. volvulus gen ... | 2000 | 10731575 |
| molecular evolution and phylogenetic utility of wolbachia ftsz and wsp gene sequences with special reference to the origin of male-killing. | a detailed assessment of the evolution and phylogenetic utility of two genes, ftsz and wsp, was used to investigate the origin of male-killing wolbachia, previously isolated from the ladybird adalia bipunctata and the butterfly acraea encedon. the analysis included almost all available sequences of b-group wolbachia and two outgroup taxa and showed that (1) the two gene regions differ in phylogenetic utility, (2) sequence variation is here correlated with phylogenetic information content, (3) bo ... | 2000 | 10742050 |
| tissue distribution and prevalence of wolbachia infections in tsetse flies, glossina spp. | tsetse flies glossina spp. (diptera: glossinidae) harbor three different symbiotic microorganisms, one being an intracellular rickettsia of the genus wolbachia. this bacterium infects a wide range of arthropods, where it causes a variety of reproductive abnormalities, one of which is termed cytoplasmic incompatibility (ci) that, when expressed, results in embryonic death due to disruptions in fertilization events. we report here that in colonized flies, wolbachia infections can be detected in 10 ... | 2000 | 10759311 |
| endosymbiotic bacteria in worms as targets for a novel chemotherapy in filariasis. | endosymbiotic bacteria living in plasmodia or worm parasites are required for the homoeostasis of their host and should be excellent targets for chemotherapy of certain parasitic diseases. we show that targeting of wolbachia spp bacteria in onchocerca volvulus filariae by doxycycline leads to sterility of adult worms to an extent not seen with drugs used against onchocerciasis, a leading cause of blindness in african countries. | 2000 | 10770311 |
| inflammatory responses induced by the filarial nematode brugia malayi are mediated by lipopolysaccharide-like activity from endosymbiotic wolbachia bacteria. | the pathogenesis of filarial disease is characterized by acute and chronic inflammation. inflammatory responses are thought to be generated by either the parasite, the immune response, or opportunistic infection. we show that soluble extracts of the human filarial parasite brugia malayi can induce potent inflammatory responses, including tumor necrosis factor (tnf)-alpha, interleukin (il)-1beta, and nitric oxide (no) from macrophages. the active component is heat stable, reacts positively in the ... | 2000 | 10770808 |
| wolbachia bacteria of filarial nematodes: a target for control? | 2000 | 10782070 | |
| offsetting effects of wolbachia infection and heat shock on sperm production in drosophila simulans: analyses of fecundity, fertility and accessory gland proteins. | infection in drosophila simulans with the endocellular symbiont wolbachia pipientis results in egg lethality caused by failure to properly initiate diploid development (cytoplasmic incompatibility, ci). the relationship between wolbachia infection and reproductive factors influencing male fitness has not been well examined. here we compare infected and uninfected strains of d. simulans for (1) sperm production, (2) male fertility, and (3) the transfer and processing of two accessory gland protei ... | 2000 | 10790392 |
| targeting of wolbachia endobacteria in litomosoides sigmodontis: comparison of tetracyclines with chloramphenicol, macrolides and ciprofloxacin. | endobacteria of the genus wolbachia in filarial nematodes are related to rickettsiaceae and can be depleted by tetracycline antibiotics. this depletion blocks female worm development as well as early embryogenesis, in contrast to the currently used microfilaricidal ivermectin which blocks only the last stage of embryogenesis. since targeting wolbachia is becoming an area of research for the treatment of human filariases, it was investigated if antibiotics other than tetracyclines are able to dep ... | 2000 | 10810023 |
| targeting of wolbachia endobacteria in litomosoides sigmodontis: comparison of tetracyclines with chloramphenicol, macrolides and ciprofloxacin | endobacteria of the genus wolbachia in filarial nematodes are related to rickettsiaceae and can be depleted by tetracycline antibiotics. this depletion blocks female worm development as well as early embryogenesis, in contrast to the currently used microfilaricidal ivermectin which blocks only the last stage of embryogenesis. since targeting wolbachia is becoming an area of research for the treatment of human filariases, it was investigated if antibiotics other than tetracyclines are able to dep ... | 2000 | 10810024 |
| infectious parthenogenesis. | parthenogenesis-inducing wolbachia bacteria are reproductive parasites that cause infected female wasps to produce daughters without mating. this manipulation of the host's reproduction enhances the transmission of wolbachia to future generations because the bacteria are passed on vertically only from mothers to daughters. males are dead ends for cytoplasmically inherited bacteria: they do not pass them on to their offspring. vertical transmission of wolbachia has been previously considered to b ... | 2000 | 10821272 |
| [wolbachia--a new bacteria causing sex ratio bias in the two-spot lady-bird adalia bipunctata l]. | some of the male-killing lines of the two-spot ladybird adalia bipunctata l. isolated from the populations of moscow and tomsk and having a female-biased sex ratio were found to be infected with a bacterium of the genus wolbachia. this fact is the first demonstration of the ability of wolbachia to kill males of a host insect. the coexistence of females infected with different male-killing bacteria was recorded in the population of moscow. | 2000 | 10822808 |
| wolbachia density and host fitness components in muscidifurax uniraptor (hymenoptera: pteromalidae). | intracellular bacteria of the genus wolbachia are found in a variety of arthropod hosts, where they cause various reproductive disorders. attempts to study the fitness advantages and disadvantages of carrying these symbionts have yielded contradicting results. using various doses of the antibiotic rifampicin, we were able to manipulate the density of wolbachia in the uniparental parasitoid muscidifurax uniraptor (hymenoptera: pteromalidae). the effect of different titers of the symbiont on the f ... | 2000 | 10843833 |
| multiple causes of male-killing in a single sample of the two-spot ladybird, adalia bipunctata (coleoptera: coccinellidae) from moscow. | thirty-six matrilines from a single muscovite sample of adalia bipunctata were assayed, using appropriate primers, for presence of the four male-killing symbionts known to infect this species of ladybird. all four, a rickettsia, a spiroplasma and two different strains of wolbachia, were found to be present. vertical transmission efficiencies were assessed from f1 and f2 families from each of the matrilines, and were found to differ significantly between symbionts. potential explanations of the p ... | 2000 | 10849086 |
| male killing can select for male mate choice: a novel solution to the paradox of the lek. | in lekking species, intense directional selection is applied to aspects of the male genotype by female choice. under conventional quantitative genetics theory, the expectation is that this will lead to a rapid loss in additive genetic variance for the trait in question. however, despite female choice, male variation is maintained and hence it pays females to continue choosing. this has been termed the 'paradox of the lek'. here we present a theoretical analysis of a putative sex-role-reversed le ... | 2000 | 10853728 |
| wsp gene sequences from the wolbachia of filarial nematodes. | wolbachia endosymbiotic bacteria are widespread in arthropods and are also present in filarial nematodes. almost all filarial species so far examined have been found to harbor these endosymbionts. the sequences of only three genes have been published for nematode wolbachia (i.e., the genes coding for the proteins ftsz and catalase and for 16s rrna). here we present the sequences of the genes coding for the wolbachia surface protein (wsp) from the endosymbionts of eight species of filaria. comple ... | 2000 | 10856373 |
| onchocerca ochengi infections in cattle as a model for human onchocerciasis: recent developments. | the bovine parasite onchocerca ochengi is a nodule-dwelling filarial nematode, closely related to o. volvulus, the causal agent of human river blindness, and, sharing with it, the same vector. this brief review, based on a presentation at the bsp autumn symposium 1999, describes recent work supported by the who drug development research macrofil programme and the edna mcconnell clark foundation vaccine development programme, to research the chemotherapy and immunology of onchocerciasis utilising ... | 2000 | 10874716 |
| macrofilaricidal activity of tetracycline against the filarial nematode onchocerca ochengi: elimination of wolbachia precedes worm death and suggests a dependent relationship. | filarial nematodes are important and widespread parasites of animals and humans. we have been using the african bovine parasite onchocerca ochengi as a chemotherapeutic model for o. volvulus, the causal organism of 'river blindness' in humans, for which there is no safe and effective drug lethal to adult worms. here we report that the antibiotic, oxytetracycline is macrofilaricidal against o. ochengi. in a controlled trial in cameroon, all adult worms (as well as microfilariae) were killed, and ... | 2000 | 10885510 |
| wolbachia infection and cytoplasmic incompatibility in the cricket teleogryllus taiwanemma. | wolbachia are cytoplasmically inherited bacteria found in many arthropods. they induce various reproductive alterations in their hosts, including cytoplasmic incompatibility, thelytokous parthenogenesis, feminization and male-killing. in this study, we examined wolbachia infection and its effects on the host cricket teleogryllus taiwanemma. in a phylogenetic study based on the wsp gene coding for a wolbachia surface protein, the wolbachia strain harboured by t. taiwanemma was clustered together ... | 2000 | 10903165 |
| comparative genomics of mitochondrial dna in drosophila simulans. | the current study compares the nucleotide variation among 22 complete mitochondrial genomes of the three distinct drosophila simulans haplotypes with intron 1 of the alcohol dehydrogenase-related locus. this is the first study to investigate the sequence variation of multiple complete mitochondrial genomes within distinct mitochondrial haplotypes of a single species. patterns of variation suggest distinct forces are influencing the evolution of mitochondrial dna (mtdna) and autosomal dna in d. s ... | 2000 | 10903373 |
| evidence for female mortality in wolbachia-mediated cytoplasmic incompatibility in haplodiploid insects: epidemiologic and evolutionary consequences. | until now, only two wolbachia-mediated cytoplasmic incompatibility (ci) types have been described in haplodiploid species, the first in nasonia (insect) and the second in tetranychus (acari). they both induce a male-biased sex ratio in the incompatible cross. in nasonia, ci does not reduce fertility since incompatible eggs develop as haploid males, whereas in tetranychus ci leads to a partial mortality of incompatible eggs, thus reducing the fertility of females. here, we study wolbachia infecti ... | 2000 | 10937195 |
| mating interactions between two biotypes of the whitefly, bemisia tabaci (hemiptera: aleyrodidae) in australia. | the biological consequences of mating interactions between indigenous and exotic biotypes of bemisia tabaci (gennadius) in australia were studied using a combination of field and laboratory experiments. the key results of the interaction between the b and eastern australian biotypes were reduced population increase, a marked increase in the proportion of male progeny, fewer eggs produced by females paired with males of different biotype and no difference in the numbers of eggs per unmated female ... | 2000 | 10948369 |
| dynamics of wolbachia populations in transfected lines of trichogramma. | fluorescence in situ hybridization was tested to specifically detect symbionts of the genus wolbachia in trichogramma and to allow for semiquantitative estimations of symbiont abundance. extraction solutions used for horizontal transfers of symbionts contain a high abundance of wolbachia, but wolbachia have a low and decreasing abundance in microinjected lines (transfected lines). moreover, eggs of microinjected lines were shown to be polymorphic for the infection. in naturally infected lines, w ... | 2000 | 10963399 |
| long pcr improves wolbachia dna amplification: wsp sequences found in 76% of sixty-three arthropod species. | bacteria belonging to the genus wolbachia are associated with a variety of reproductive anomalies in arthropods. allele-specific polymerase chain reaction (= standard pcr) routinely has been used to amplify wolbachia dna from arthropods. while testing the two-spotted spider mite tetranychus urticae and other arthropods known to be infected with wolbachia, standard pcr frequently produced false negatives, perhaps because the dna from the arthropod host interfered with amplification by taq dna pol ... | 2000 | 10971717 |
| wolbachia infection frequencies in insects: evidence of a global equilibrium? | wolbachia are a group of cytoplasmically inherited bacteria that cause reproduction alterations in arthropods, including parthenogenesis, reproductive incompatibility, feminization of genetic males and male killing. previous general surveys of insects in panama and britain found wolbachia to be common, occurring in 16-22% of species. here, using similar polymerase chain reaction methods, we report that 19.3% of a sample of temperate north american insects are infected with wolbachia, a frequency ... | 2000 | 10972121 |
| male-killing wolbachia in a flour beetle. | the bacteria in the genus wolbachia are cytoplasmically inherited symbionts of arthropods. infection often causes profound changes in host reproduction, enhancing bacterial transmission and spread in a population. the reproductive alterations known to result from wolbachia infection include cytoplasmic incompatibility (ci), parthenogenesis, feminization of genetic males, fecundity enhancement, male killing and, perhaps, lethality here, we report male killing in a third insect, the black flour be ... | 2000 | 10983833 |
| evolutionary novelties in islands: drosophila santomea, a new melanogaster sister species from são tomé. | the finding of new melanogaster sister species may help us in understanding more about how the emergence of genetic novelties, particularly in insular habitats, can result in speciation. here we report on the discovery of drosophila santomea, which is the first melanogaster sibling found off west-equatorial africa, on são tomé, one of the gulf of guinea islands. although the eight other melanogaster sister species are remarkably conservative in their morphology except for their terminalia, the n ... | 2000 | 11007323 |
| lipopolysaccharide-like molecules derived from wolbachia endobacteria of the filaria onchocerca volvulus are candidate mediators in the sequence of inflammatory and antiinflammatory responses of human monocytes. | the majority of onchocerca volvulus-infected persons show signs of cellular anergy, and long-time survival of adult and larval parasites in subcutaneous tissue is observed. the mechanisms leading to immunological hyporesponsiveness are poorly understood. monocytes/macrophages represent a link between the innate and acquired immune system and are candidate cells to promote inflammatory and antiinflammatory processes. in the present study we have shown that products of microfilarial (o. volvulus) ... | 2000 | 11008105 |
| transinfection of wolbachia in the mediterranean flour moth, ephestia kuehniella, by embryonic microinjection. | wolbachia are maternally transmitted intracellular bacteria found in many arthropod species. they cause a reproductive incompatibility called cytoplasmic incompatibility (ci) in several hosts, including the mediterranean flour moth, ephestia kuehniella. two strains of e. kuehniella, one from yokohama city and the other from tsuchiura city, express different levels of ci: the yokohama strain expresses ci at a higher level than the tsuchiura strain. in order to determine whether the difference of ... | 2000 | 11012714 |
| wolbachia segregation rate in drosophila simulans naturally bi-infected cytoplasmic lineages. | wolbachia are maternally transmitted endocellular bacteria infecting several arthropod species. in order to study wolbachia segregation rate, drosophila simulans females from an indo-pacific population (seychelles) bi-infected by the two wolbachia variants wha and wno were backcrossed to uninfected males in two conditions. in the first case, seychelles males from a stock cured from its wolbachia by tetracycline treatment were used. in the second case, the males came from a naturally uninfected t ... | 2000 | 11012722 |
| male-killing wolbachia in drosophila: a temperature-sensitive trait with a threshold bacterial density. | inherited microorganisms that disturb the reproduction of their host have been characterized from a number of host taxa. to understand the general principles underlying the genetic and mechanistic basis of interactions, study of different agents in model host species is required. to this end, the nature and genetics of the maternally inherited sex-ratio trait of drosophila bifasciata were investigated. successful curing of affected lines with antibiotics demonstrated this trait was associated wi ... | 2000 | 11014817 |
| ultrastructural and molecular identification of a wolbachia endosymbiont in a spider, nephila clavata. | wolbachia-like bacteria were observed in the egg cells of golden orb-weaving spider, nephila clavata, by means of transmission electron microscopy. the bacteria exhibited the typical morphology of wolbachia, including three enveloping membranes. based on the amplification and sequencing of partial 16s rdna and ftsz gene, the bacteria were identified as wolbachia, intracellular, transovarially inherited alpha-proteobacteria in invertebrates. phylogenetic analysis based on 16s rdna and ftsz gene s ... | 2000 | 11029673 |
| tetracycline inhibits development of the infective-stage larvae of filarial nematodes in vitro. | in recent years, studies have linked tetracycline treatment of filaria-infected animals with reduced adult worm burdens and decreased levels of microfilaremia. these observations are believed to be attributable to clearance of wolbachia, intracellular rickettsial-like organisms found within filarial tissues. although maximal worm reductions were observed when treatment was initiated early in infection, it is not known whether tetracycline inhibits development of infective-stage larvae. to addres ... | 2000 | 11038309 |
| addition of wsp sequences to the wolbachia phylogenetic tree and stability of the classification. | wolbachia are symbiotic bacteria altering reproductive characters of numerous arthropods. their most recent phylogeny and classification are based on sequences of the wsp gene. we sequenced wsp gene from six wolbachia strains infecting six trichogramma species that live as egg parasitoids on many insects. this allows us to test the effect of the addition of sequences on the wolbachia phylogeny and to check the classification of wolbachia infecting trichogramma. the six wolbachia studied are clas ... | 2000 | 11040288 |
| influential passengers come of age. 1st international wolbachia conference, orthodox academy, kolymbari, crete, greece, 7-12 june 2000. | 2000 | 11041802 | |
| genes for the type iv secretion system in an intracellular symbiont, wolbachia, a causative agent of various sexual alterations in arthropods. | wolbachia species are intracellular bacteria known to cause reproductive abnormalities in their hosts. in this study, we identified wolbachia genes encoding homologs to the type iv secretion system by which many pathogenic bacteria secrete macromolecules. the genes identified encoded most of the essential components of the secretion system and were cotranscribed as an operon. | 2000 | 11053403 |
| wolbachia-induced 'hybrid breakdown' in the two-spotted spider mite tetranychus urticae koch. | the most common post-zygotic isolation mechanism between populations of the phytophagous mite tetranychus urticae is 'hybrid breakdown', i.e. when individuals from two different populations are crossed, f1 hybrid females are produced, but f2 recombinant male offspring suffer increased mortality. two-spotted spider mites collected from two populations, one on rose and the other on cucumber plants, were infected with wolbachia bacteria. these bacteria may induce cytoplasmic incompatibility in thei ... | 2000 | 11075704 |
| distribution and evolution of bacteriophage wo in wolbachia, the endosymbiont causing sexual alterations in arthropods. | wolbachia are obligatory intracellular and maternally inherited bacteria, known to infect many species of arthropod. in this study, we discovered a bacteriophage-like genetic element in wolbachia, which was tentatively named bacteriophage wo. the phylogenetic tree based on phage wo genes of several wolbachia strains was not congruent with that based on chromosomal genes of the same strains, suggesting that phage wo was active and horizontally transmitted among various wolbachia strains. all the ... | 2000 | 11080372 |
| expression of cytoplasmic incompatibility in drosophila simulans and its impact on infection frequencies and distribution of wolbachia pipientis. | the aim of this study is to examine the expression of cytoplasmic incompatibility and investigate the distribution and population frequencies of wolbachia pipientis strains in drosophila simulans. nucleotide sequence data from 16s rdna and a wolbachia surface protein coding sequence and cytoplasmic incompatibility assays identify four distinct wolbachia strains: wha, wri, wma, and wau. the levels of cytoplasmic incompatibility between six lines carrying these strains of bacteria and three contro ... | 2000 | 11108593 |
| wolbachia neither induces nor suppresses transcripts encoding antimicrobial peptides. | wolbachia are intracellular maternally inherited microorganisms that are associated with reproductive abnormalities such as cytoplasmic incompatibility (ci), feminization and parthenogenesis in the various arthropod species they infect. surveys indicate that these bacteria infect more than 16% of all insect species as well as isopods, mites and nematodes, making wolbachia one of the most ubiquitous parasites yet described. however, nothing is known about the interactions of this bacterium with t ... | 2000 | 11122472 |
| wolbachia infections in native and introduced populations of fire ants (solenopsis spp.). | wolbachia are cytoplasmically inherited bacteria that induce a variety of effects with fitness consequences on host arthropods, including cytoplasmic incompatibility, parthenogenesis, male-killing and feminization. we report here the presence of wolbachia in native south american populations of the fire ant solenopsis invicta, but the apparent absence of the bacteria in introduced populations of this pest species in the usa. the wolbachia strains in native s. invicta are of two divergent types ( ... | 2000 | 11122476 |
| physiological cost induced by the maternally-transmitted endosymbiont wolbachia in the drosophila parasitoid leptopilina heterotoma. | endosymbiotic bacteria of the genus wolbachia infect a number of invertebrate species in which they induce various alterations in host reproduction, mainly cytoplasmic incompatibility (ci). in contrast to most other maternally transmitted parasites, manipulation of host reproduction makes the spread of wolbachia possible even if they induce a physiological cost on their hosts. current studies have shown that fitness consequences of wolbachia infection could range from positive (mutualist) to neg ... | 2000 | 11128800 |
| occurrence of novel verrucomicrobial species, endosymbiotic and associated with parthenogenesis in xiphinema americanum-group species (nematoda, longidoridae). | numerous micro-organisms have been described as cytoplasmic symbionts of eukaryotes. many so-called obligate endosymbionts rely exclusively on maternal (vertical or transovarial) transmission to maintain themselves, rendering them dependent on the host sex ratio, which they would tend to manipulate to their own advantage. the latter phenomenon is often associated with the presence of wolbachia pipientis (alpha-proteobacteria) in arthropods and nematodes. a potentially similar situation was disco ... | 2000 | 11155997 |
| mosquito engineering. building a disease-fighting mosquito. | with resistance against insecticides on the rise and a u.n.-backed push to phase out ddt, several labs have embarked on the most ambitious and futuristic of all approaches to combat malaria: they hope to replace billions and billions of mosquitoes in the world's endemic areas with new strains, created in the lab, that would be "refractory," or unable to transmit plasmodium, the parasite that causes the disease. the idea is not that farfetched, these researchers claim. | 2000 | 11183760 |
| automictic parthenogenesis in the parasitoid venturia canescens (hymenoptera: ichneumonidae) revisited. | both arrhenotokous and thelytokous reproduction are known to occur in the parasitoid wasp venturia canescens. the cytological mechanism of thelytoky was previously reported to involve the formation of a restitution metaphase after the reduction division, but the exact nature of the subsequent divisions, whether reductional or equational, remained unclear. we reinvestigated the cytological mechanisms in a thelytokous strain collected in france. our observations confirm previous results, but an eq ... | 2000 | 11195346 |
| antigenic role of the endosymbionts of filarial nematodes: igg response against the wolbachia surface protein in cats infected with dirofilaria immitis. | filarial nematodes harbour intracellular endosymbiotic bacteria, which have been assigned to the genus wolbachia. these bacteria appear to play an important role in the pathogenesis of filarial diseases through their lipopolysaccharides. in view of the presence of wolbachia endosymbionts in the body of filarial nematodes, one might also expect that proteins from these bacteria play an antigenic role in humans and animals affected by filariases. to test this hypothesis, we produced in recombinant ... | 2000 | 11197127 |
| 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 |
| wolbachia bacteria of filarial nematodes in the pathogenesis of disease and as a target for control. | 2000 | 11198638 | |
| diseases of mites. | an overview is given of studies on diseases of mites. knowledge of diseases of mites is still fragmentary but in recent years more attention has been paid to acaropathogens, often because of the economic importance of many mite species. most research on mite pathogens concerns studies on fungal pathogens of eriophyoids and spider mites especially. these fungi often play an important role in the regulation of natural mite populations and are sometimes able to decimate populations of phytophagous ... | 2000 | 11201358 |
| mechanisms of conspecific sperm precedence in drosophila. | the postmating, prezygotic isolating mechanism known as conspecific sperm precedence (csp) may play an important role in speciation, and understanding the mechanism of csp is important in reconstructing its evolution. when a drosophila simulans female mates with both a d. simulans male and a d. mauritiana male, the vast majority of her progeny are fathered by d. simulans, regardless of the order of mating. the dearth of hybrid progeny does not result from inviability of eggs fertilized by hetero ... | 2000 | 11209779 |
| antibiotics and wolbachia in filarial nematodes: antifilarial activity of rifampicin, oxytetracycline and chloramphenicol against onchocerca gutturosa, onchocerca lienalis and brugia pahangi. | the activity against filarial parasites of the antibiotics rifampicin, oxytetracycline and chloramphenicol was examined. in addition, transmission electron microscopy was used to study the effects of rifampicin and oxytetracycline on filarial tissues and on the endosymbiont bacterium, wolbachia. when tested in vitro at a concentration of 50.0 microm, each of the three antibiotics significantly reduced the motility levels of male onchocerca gutturosa. rifampicin, however, was the most active, vir ... | 2000 | 11214099 |
| infectious speciation. | 2001 | 11217844 | |
| 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 |
| 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 |
| 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 |
| 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 |
| evolution. nota bene. wolbachia and wasp evolution. | 2001 | 11253199 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |