the ultrastructure and symbiotic relationships of wolbachia of mosquitoes of the aedes scutellaris group. 19807411685
wolbachia pipientis: bacterial density and unidirectional cytoplasmic incompatibility between infected populations of aedes albopictus.unidirectional cytoplasmic incompatibility is seen when certain wolbachia-infected insect populations are crossed. two hypotheses might explain this phenomenon: superinfections with mutually incompatible strains of wolbachia producing incompatibility when crossed to individuals infected with only a single bacterial strain or, alternatively, a bacterial dosage model, with differences in wolbachia densities responsible for the incompatibility. a quantitative pcr assay was set up as a general metho ...19957498425
wolbachia endosymbionts responsible for various alterations of sexuality in arthropods.rickettsia-like maternally inherited bacteria have been shown to be involved in a variety of alterations of arthropod sexuality, such as female-biased sex ratios, parthenogenesis, and sterility of crosses either between infected males and uninfected females or between infected individuals (cytoplasmic incompatibility). we have characterized several of these microorganisms through partial sequences of the small (16s) and large (23s) subunit ribosomal dna. all the symbionts identified, which inclu ...19921361987
cytoplasmic incompatibility in drosophila simulans: dynamics and parameter estimates from natural drosophila simulans, cytoplasmically transmitted wolbachia microbes cause reduced egg hatch when infected males mate with uninfected females. a wolbachia infection and an associated mtdna variant have spread northward through california since 1986. pcr assays show that wolbachia infection is prevalent throughout the continental us and central and south america, but some lines from florida and ecuador that are pcr-positive for wolbachia do not cause incompatibility. we estimate from natural po ...19957498773
increased male fertility in tribolium confusum beetles after infection with the intracellular parasite wolbachia.the cytoplasmically inherited microorganism wolbachia pipientis behaves like a sexually selected trait in its host, the flour beetle tribolium confusum, enhancing male fertility at the expense of female fecundity. here we show that infected females have fewer offspring than uninfected females but infected males have a large fertility advantage over uninfected males within multiply-inseminated infected or uninfected females. the male fertility effect accelerates the spread of the wolbachia throug ...19957800041
the reproductive incompatibility system in drosophila simulans: dapi-staining analysis of the wolbachia symbionts in sperm cysts.any hitherto available technique used to detect the presence of wolbachia, a rickettsia-like endosymbiont of drosophila simulans, i.e., crossing with tester strains, electron microscope observations, dapi-staining of embryo, or amplification of specific sequences by pcr are notably time-consuming techniques. staining sperm cysts with the fluorochrome dapi is here shown to be a fast and reliable technique to detect the symbiont and evaluate the level of infection of individual males. wolbachia ce ...19937689622
evolution of single and double wolbachia symbioses during speciation in the drosophila simulans complex.maternally inherited bacteria of the genus wolbachia are responsible for the early death of embryos in crosses between uninfected females and infected males in several insect species. this phenomenon, known as cytoplasmic incompatibility, also occurs between strains infected by different symbionts in some species, including drosophila simulans. wolbachia was found in two species closely related to d. simulans, drosophila mauritiana, and drosophila sechellia, and shown to cause incompatibility in ...19957604001
evolution and phylogeny of wolbachia: reproductive parasites of arthropods.wolbachia are cytoplasmically inherited bacteria found in reproductive tissues of many arthropod species. these bacteria are associated with reproductive alterations in their hosts, including parthenogenesis, reproductive incompatibility and feminization. a fine-scale phylogenetic analysis was done using dna sequences from ftsz, a rapidly evolving bacterial cell-cycle gene. ftsz sequences were determined for 38 different wolbachia strains from 31 different species of insects and one isopod. the ...19957644549
cloning and characterization of an ftsz homologue from a bacterial symbiont of drosophila melanogaster.a 1194 bp open reading frame that codes for a 398 amino acid peptide was cloned from a lambda gt11 library of drosophila melanogaster genomic dna. the predicted peptide sequence is very similar to three previously characterized protein sequences that are encoded by the ftsz genes in escherichia coli, bacillus subtilis and rhizobium meliloti. the ftsz protein has a major role in the initiation of cell division in prokaryotic cells. using a tetracycline treatment that eradicates bacterial parasite ...19937689140
wolbachia infections and the expression of cytoplasmic incompatibility in drosophila sechellia and d. mauritiana.various stocks of drosophila mauritiana and d. sechellia were found to be infected with wolbachia, a rickettsia-like bacterium that is known to cause cytoplasmic incompatibility and other reproductive abnormalities in arthropods. testing for the expression of cytoplasmic incompatibility in these two species showed partial incompatibility in d. sechellia but no expression of incompatibility in d. mauritiana. to determine whether absence of cytoplasmic incompatibility in d. mauritiana was due to e ...19957498772
evidence for a wolbachia symbiont in drosophila melanogaster.the bacterial cell division gene, ftsz, was used as a specific probe to show the presence of a symbiotic bacterium in two wild type strains of drosophila melanogaster. under stringent hybridization conditions we have shown that the bacterium is transferred to the progeny of these strains from infected mothers and can be eradicated by treatment with the antibiotic tetracycline. we have characterized this bacterium, by amplifying and sequencing its 16s rrna gene, as being a member of the genus wol ...19937691685
organization of wolbachia pipientis in the drosophila fertilized egg and embryo revealed by an anti-wolbachia monoclonal antibody.cytoplasmic incompatibility (ci) in drosophila is related to the presence of wolbachia, an intracellular microorganism found in many species of insects. in order to study the intracellular localization of wolbachia in eggs and embryos, we have purified the bacteria from fly embryos and subsequently generated a monoclonal antibody (mab wol-1) specific for wolbachia. indirect immunofluorescence staining using wol-1 reveals that during mitosis, wolbachia are localized near spindle poles and centros ...19957547474
diversity within diversity: molecular approaches to studying microbial interactions with insects.dna sequence information has greatly augmented the number of characters available for analysis in phylogenetic research. nowhere is this more evident than in studies of microbial evolution. ribosomal dna sequence data has simultaneously permitted the distinction between individual species and the inference of their phylogenetic relationships in many cases where both were formerly impossible. these have contributed to our understanding of the ecology of particular microbe-host interactions and th ...19947994122
wolbachia and cytoplasmic incompatibility in mycophagous drosophila and their relatives.bacterial symbionts belonging to the genus wolbachia are associated with postzygotic reproductive incompatibility in a number of insect species. using polymerase chain reaction (pcr) amplification of bacterial gene sequences, strains from 10 species belonging to the closely related quinaria, testacea and tripunctata groups of drosophila were screened for the presence of wolbachia in their reproductive tissues. those screened included the mycophagous species d. falleni, d. recens, d. phalerata, d ...19957558891
induction of paternal genome loss by the paternal-sex-ratio chromosome and cytoplasmic incompatibility bacteria (wolbachia): a comparative study of early embryonic events.paternal genome loss (pgl) during early embryogenesis is caused by two different genetic elements in the parasitoid wasp, nasonia vitripennis. paternal sex ratio (psr) is a paternally inherited supernumerary chromosome that disrupts condensation of the paternal chromosomes by the first mitotic division of fertilized eggs. bacteria belonging to the genus wolbachia are present in nasonia eggs and also disrupt paternal chromosome condensation in crosses between cytoplasmically incompatible strains. ...19957598906
taxonomic position of the rickettsiae: current knowledge.the term rickettsiae initially encompassed all intracellular bacteria. early rickettsial taxonomy was based on a comparison of a few phenotypic characteristics and recently, molecular studies brought new bases for rickettsial taxonomy. all rickettsial species studied so far belong to the alpha and gamma groups of the proteobacteria. ehrlichiae complex groups cowdria ruminantium, anaplasma marginale and wolbachia pipientis and the related parthenogenesis and cytoplasmic incompatibility bacteria, ...19948117465
a rickettsia-like microorganism similar to wolbachia pipientis and its occurrence in culex mosquitoes. 19836863975
phylogenetic analysis of the genus rickettsia by 16s rdna sequencing.rickettsiae are gram-negative bacteria which multiply only inside host cells and need arthropods either as reservoirs or as vectors. using the polymerase chain reaction and an automated laser fluorescent dna sequencer, we amplified and sequenced the 16s rrna (rdna) of all available bacteria of the genus rickettsia. r. tsutsugamushi remained close to the other bacteria of the genus rickettsia using this technique, contrary to previous conclusions based on the study of the sta-58 protein antigen. ...19958525055
reproduction of an inbred strain of culex pipiens prevented by loss of wolbachia pipientis. 19836404990
characterization of the unlinked 16s rdna and 23s-5s rrna operon of wolbachia pipientis, a prokaryotic parasite of insect gonads.the rrna-encoding genes (rdnas) have been cloned and characterized from wolbachia pipientis (wp), the gonadial bacteria-like parasite of the mosquito culex pipiens (cp) and the moth ephestia cautella (ec). in wp from both insect species the rdnas are organized in a way which appears to be very unusual. the rrnas are encoded by two unlinked transcription units, each present in a single copy per genome. one contains the 16s rdna only, while the other is an operon encoding both the 23s and 5s rdnas ...19957489921
interspecific and intraspecific horizontal transfer of wolbachia in drosophila.cytoplasmic incompatibility (ci) in drosophila simulans is related to infection of the germ line by a rickettsial endosymbiont (genus wolbachia). wolbachia were transferred by microinjection of egg cytoplasm into uninfected eggs of both d. simulans and d. melanogaster to generate infected populations. transinfected strains of d. melanogaster with lower densities of wolbachia than the naturally infected d. simulans strain did not express high levels of ci. however, transinfected d. melanogaster e ...19938511587
phylogenetic diversity of the rickettsiae.small subunit rrna sequences have been determined for representative strains of six species of the family rickettsiaceae: rickettsia rickettsii, rickettsia prowazekii, rickettsia typhi, coxiella burnetii, ehrlichia risticii, and wolbachia persica. the relationships among these sequences and those of other eubacteria show that all members of the family rickettsiaceae belong to the so-called purple bacterial phylum. the three representatives of the genus rickettsia form a tight monophyletic cluste ...19892753854
factors affecting the distribution of cytoplasmic incompatibility in drosophila drosophila simulans a wolbachia-like microorganism is responsible for reduced egg-hatch when infected males mate with uninfected females. both incompatibility types have previously been found in north america, europe and africa. some california populations have remained polymorphic for over two years, and the infection is apparently spreading in central california. egg hatch proportions for wild-caught females from polymorphic populations show that the incompatibility system acts in nature, b ...19902076821
geographic distribution and inheritance of three cytoplasmic incompatibility types in drosophila simulans.wolbachia-like microorganisms have been implicated in unidirectional cytoplasmic incompatibility between strains of drosophila simulans. reduced egg eclosion occurs when females from uninfected strains (type w) are crossed with males from infected strains (type r). here we characterize a third incompatibility type (type s) which is also correlated with the presence of wolbachia-like microorganisms. despite the fact that the symbionts cannot be morphologically distinguished, we observed complete ...19911743484
rickettsiaceae and chlamydiaceae: comparative electron microscopic studies.the structure and cytopathology of obligate intracellular bacteria belonging to families rickettsiaceae and chlamydiaceae and their interaction with eukaryotic host cells were compared in electron microscopic studies. "rickettsia-like" and "chlamydia-like" types of organization of bacterial cells and their interaction with host cells are presented. the rickettsia-like type is characterized by short rod-shaped cells multiplying freely ( extravacuolarly ) in the cytoplasm or nucleoplasm of the hos ...19846145350
molecular identification of wolbachia, the agent of cytoplasmic incompatibility in drosophila simulans, and variability in relation with host mitochondrial types.sequences of a segment of the 16s ribosomal dna of wolbachia, a rickettsia-like microorganism responsible for cytoplasmic incompatibility in drosophila simulans, have been obtained after polymerase chain reaction (pcr) amplification. their comparison with other eubacterial sequences allows us to assign these endosymbionts to the alpha subdivision of purple bacteria. four related sequences have been obtained for microorganisms carried by eight isofemale lines representative of the three mitochond ...19921350096
fine structure of the vagina, accessory glands, uterus, oviducts and gene's organ in the unfed tick, ornithodoros (pavlovskyella) erraticus (ixodoidea: argasidae).the fine structure of the reproductive system of the unfed female ornithodoros (pavloskyella) erraticus is described. the vagina consisting of vestibular (vv) and cervical (cv) regions is formed of a single epithelial layer lined with cuticle and surrounded by muscle layers. epithelial cells of vv show no signs of activity, while those of cv have structural features of transporting epithelia. a pair of tubular accessory glands opening at the junction of the two vaginal regions consist of a layer ...19883409790
molecular evidence for a close relative of the arthropod endosymbiont wolbachia in a filarial worm. 19958719164
16s rrna phylogenetic analysis of the bacterial endosymbionts associated with cytoplasmic incompatibility in insects.bacterial endosymbionts of insects have long been implicated in the phenomenon of cytoplasmic incompatibility, in which certain crosses between symbiont-infected individuals lead to embryonic death or sex ratio distortion. the taxonomic position of these bacteria has, however, not been known with any certainty. similarly, the relatedness of the bacteria infecting various insect hosts has been unclear. the inability to grow these bacteria on defined cell-free medium has been the major factor unde ...19921557375
isolation of spotted fever group and wolbachia-like agents from field-collected materials by means of plaque formation in mammalian and mosquito cells.three isolations from ticks (dermacentor occidentalis) of a rickettsia of the spotted fever group and 5 isolations from chipmunk (eutamias rugicaudus) blood of a wolbachia-like agent were obtained from plaques formed in singh's aedes albopictus (mosquito) and vero (african green monkey kidney) cell cultures. these organisms could not be isolated by injection of the infected ticks or blood into embryonated chicken eggs, guinea pigs, or voles (microtus pennsylvanicus), but fluid cultures of grace' ...1975241251
wolbachia: intracellular manipulators of mite reproduction.cytoplasmically transmitted wolbachia (alpha-proteobacteria) are a group of closely related intracellular microorganisms that alter reproduction in arthropods. they are found in a few isopods and are widespread in insects. wolbachia are implicated as the cause of parthenogenesis in parasitic wasps, feminization in isopods and reproductive (cytoplasmic) incompatibility in many insects. here we report on the widespread occurrence of wolbachia in spider mites and predatory mites based on a pcr assa ...19968856963
piscirickettsia salmonis gen. nov., sp. nov., the causative agent of an epizootic disease in salmonid fishes.a novel intracellular pathogen morphologically similar to the ehrlichiae has been isolated in cell culture and identified as the cause of an epizootic disease of salmonid fish. like the ehrlichiae, the salmonid pathogen, designated strain lf-89, replicates within membrane-bound cytoplasmic vacuoles in host cells. this agent is the first with characteristics of this type to be isolated from a fish. analysis of the lf-89 16s rrna indicated that, unlike the ehrlichiae, lf-89 is a gamma proteobacter ...19921371057
the ultrastructure of the rickettsia-like microorganism wolbachia pipientis and associated virus-like bodies in the mosquito culex pipiens. 1978671578
in vitro cultivation of wolbachia pipientis in an aedes albopictus cell line.a continuous cell line, aa23, was established from eggs of a strain of the asian tiger mosquito, aedes albopictus, naturally infected with the intracellular symbiont wolbachia pipientis. the resulting cell line was shown to be persistently infected with the bacterial endosymbiont. treatment with antibiotics cured the cells of the infection. in the course of establishing this cell line it was noticed that rflps in the pcr products of two wolbachia genes from the parental mosquitoes were fixed in ...19979013253
transovarial transmission of rickettsia-like microorganisms in mosquitoes.the wolbachiae found in culex pipiens and the tafahi strain of the a. scutellaris group are small rickettsia-like symbionts of the gonads. they are extrachromosomal self-replicating units that are vertically transmitted through the ovaries. their presence in the only two groups of mosquitoes known to exhibit incompatibility, the fact that they are found in only the tafahi strain, and the loss of incompatibility after removal of wolbachia in c. pipiens are compelling evidence for the role that wo ...197520018
the effect of population subdivision on the rate of spread of parasite-mediated cytoplasmic incompatibility.over 20 species of arthropods are known to harbor an endosymbiotic bacterium, wolbachia associated with partial reproductive incompatibility. the micro-organism spreads through a random mating population with positive frequency dependence. many insect populations, however, are subdivided to some degree. in this paper we model the effect of population subdivision on the rate of spread of wolbachia and show that it slows the rate of spread of the micro-organism but by itself cannot cause a stable ...19947909859
electronmicroscopic investigations of wolbachia-like microorganisms in haemaphysalis inermis. 1977600395
phylogeny of the nasonia species complex (hymenoptera: pteromalidae) inferred from an internal transcribed spacer (its2) and 28s rdna sequences.the phylogeny of the cryptic species complex of wasps in the genus nasonia was inferred by analysis of nucleotide sequences of an rdna internal transcribed spacer (its2) and the d2 region of 28s rdna. phylogenetic analysis showed that n. vitripennis descended from a theoretical common ancestor with that of a lineage that diverged into n. longicornis and n. giraulti. differences in the its2 regions clearly distinguished two strains of n. giraulti. another member of the dibrachys group, trichomalo ...19939087560
cytoplasmic incompatibility in australian populations of drosophila drosophila melanogaster, weak incompatibility in crosses between infected and uninfected strains is associated with a wolbachia microorganism. crosses between infected males and uninfected females show a reduction (15-30%) in egg hatch. progeny tests indicated that the infection is widespread in australian d. melanogaster populations and that populations are polymorphic for the presence of the infection. the infection status of 266 lines from 12 populations along the eastern coast of australi ...19948005448
endosymbiotic relationship between a rickettsia-like microorganism and the male germ-cells of culex tigripes.the male mosquitoes of the species culex tigripes possess endosymbionts localized in the cytoplasm of the germ-cells. the somatic cells of the testis do not exhibit this particularity. the spermatogonia, spermatocytes and spermatids all possess a few symbionts. they are eliminated in the residual body at the end of spermiogenesis when the spermatozoon matures. they are absent from the seminal vesicles. a few spermatocytes and spermatids show a proliferation of the endosymbionts. this seems to be ...19938096432
replacement of the natural wolbachia symbiont of drosophila simulans with a mosquito counterpart.inherited rickettsial symbionts of the genus wolbachia occur commonly in arthropods and have been implicated in the expression of parthenogenesis, feminization and cytoplasmic incompatibility wolbachia from the asian tiger mosquito, aedes albopictus, to replace the natural infection of drosophila simulans by means of embryonic microinjection techniques. the transferred wolbachia infection behaves like a natural drosophila infection with regard to its inheritance, cytoskeleton interactions and ab ...19947906391
analysis of 16s ribosomal dna sequences of francisella strains and utilization for determination of the phylogeny of the genus and for identification of strains by pcr.the 16s ribosomal dnas (rdnas) of two strains of francisella tularensis and one strain of francisella philomiragia were sequenced. on the basis of phylogenetic analysis data, the genus francisella was placed in the gamma subclass of the proteobacteria. the most closely related organism was the intracellular bacterium wolbachia persica. the sequenced 16s rdna molecules of the francisella species exhibited very high levels of similarity (98.5 to 99.9%). two variable regions, comprising 390 to 450 ...19948123561
horizontal transmission of parthenogenesis-inducing microbes in trichogramma wasps.complete parthenogenesis (thelytoky) in species of the parasitic wasp trichogramma is usually caused by the cytoplasmically inherited bacterium wolbachia. this symbiont induces gamete duplication, which, in these haplodiploid organisms, results in all-female broods. antibiotic treatment "cures' this condition, restoring normal sexual reproduction. phylogenetic analysis of wolbachia has shown that, in contrast with the strains in other host organisms (where the symbiont also induces different rep ...19979107051
a prokaryotic dnaa sequence in drosophila melanogaster: wolbachia infection and cytoplasmic incompatibility among laboratory strains.using oligonucleotide primers derived from the aligned polypeptide sequences of several prokaryotic dnaa genes, we amplified from drosophila melanogaster dna a 557 bp fragment containing a single open reading frame. the predicted peptide sequence shows a significant similarity to previously characterized protein sequences that are encoded by the dnaa genes of several prokaryotes. the dnaa sequences are also detectable by pcr in dna from drosophila simulans and nasonia vitripennis flies which are ...19947894745
ultrastructure of spotted fever rickettsialike microorganisms observed in tissues of dermacentor taiwanensis (acari: ixodidae).tissues of midguts, malpighian tubules, salivary glands, and ovaries of female dermacentor taiwanensis sugimoto collected in an area endemic for japanese spotted fever were examined with an electron microscope, and the presence of two kinds of rickettsialike microorganisms was confirmed in japan. based on ultrastructural findings, a rod-shaped organism detected in all the tissues is a rickettsia; another, irregularly shaped organism that was found only in the ovary, is a wolbachia. a hemolymph t ...19938510117
wolbachia run amok. 19979326576
groe-homologous operon of wolbachia, an intracellular symbiont of arthropods: a new approach for their phylogeny.wolbachia, a member of rickettsia found in the cells of many arthropod species, are cytoplasmically inherited bacteria which interfere with host's sexuality and reproduction. wolbachia strains have been phylogenetically divided into a and b groups based on the nucleotide sequences of their ftsz genes. in an attempt to further define the phylogenetical relationship among these endosymbionts, we cloned and sequenced the entire length of the groe operon of a wolbachia harbored by a cricket. the ope ...19979401467
conflict between feminizing sex ratio distorters and an autosomal masculinizing gene in the terrestrial isopod armadillidium vulgare latr.female sex determination in the pill bug armadillidium vulgare is frequently under the control of feminizing parasitic sex factors (psf). one of these psf is an intracytoplasmic wolbachia-like bacterium (f), while the other (f) is suspected of being an f-bacterial dna sequence unstably integrated into the host genome. in most wild populations harboring psf, all individuals are genetic males (zz), and female phenotypes occur only due to the presence of psf which overrides the male determinant car ...19938436273
properties of drosophila simulans strains experimentally infected by different clones of the bacterium wolbachia.maternally inherited bacteria of the genus wolbachia are responsible for reproductive incompatibilities between strains of drosophila simulans. such incompatibilities are known in several types of crosses, including both directions of crossing between two types of infected strains, 'r' and 's'. to determine whether the bidirectional incompatibility between r and s flies is due only to differences between their bacteria, flies from an uninfected strain have been experimentally infected with bacte ...19948200813
mitochondrial dna polymorphism and feminizing sex factors dynamics in a natural population of armadillidium vulgare (crustacea, isopoda).sex determination in armadillidium vulgare may be under the control of two parasitic sex factors that reverse genetic males into functional neo-females. the first feminizing factor (f) is a wolbachia and the other (f) is probably a sequence of the f bacterial dna unstably integrated into the host genome. both of these feminizing factors are mainly maternally transmitted. here we investigate the mitochondrial dna polymorphism of wild iso-female lineages harbouring either f or f. among the four ha ...19938163156
phylogenetically distant symbiotic microorganisms reside in glossina midgut and ovary tissues.many blood-feeding insects, including tsetse flies (diptera: glossinidae), harbour intracellular bacterial symbionts. using isolates from tissues of several glossina species and diagnostic dna oligonucleotide primers, a polymerase chain reaction (pcr) based assay was designed to identify symbiotic bacteria. those inhabiting the midgut of glossina were found to belong to the gamma subdivision, whereas ovarian proteobacteria were of the alpha subdivision--probably genus wolbachia (rickettsiaceae). ...19938268495
single and double infections with wolbachia in the parasitic wasp nasonia vitripennis: effects on compatibility.wolbachia are cytoplasmically inherited bacteria responsible for reproductive incompatibility in a wide range of insects. there has been little exploration, however, of within species wolbachia polymorphisms and their effects on compatibility. here we show that some strains of the parasitic wasp nasonia vitripennis are infected with two distinct bacterial strains (a and b) whereas others are singly infected (a or b). double and single infections are confirmed by both pcr amplification and southe ...19968725242
naturally-occurring wolbachia infection in drosophila simulans that does not cause cytoplasmic incompatibility.microbes of the genus wolbachia are transmitted by their hosts via the maternal parent and are responsible for cytoplasmic incompatibility among insect populations. this phenomenon can result in wolbachia spreading through natural populations as previously demonstrated in drosophila simulans. here we describe another wolbachia infection in d. simulans that does not cause cytoplasmic incompatibility. this is a property of the wolbachia rather than the nuclear background. the infection occurs at a ...19968575931
cytological analysis of fertilization and early embryonic development in incompatible crosses of drosophila simulans.cytoplasmic incompatibility (ci) is a unique form of male sterility found in numerous insect species that harbor a bacterial endosymbiont wolbachia. ci is characterized by severe reduction in the progeny produced when infected males are crossed to uninfected females. the reduction in progeny correlates with developmental defects that arise during and immediately following fertilization, suggesting that sperm function is disrupted. to investigate the nature of the cellular defects associated with ...19968817452
variability within the seychelles cytoplasmic incompatibility system in drosophila drosophila simulans, we described a cytoplasmic incompatibility (ci) system (seychelles) restricted to insular populations that harbor the mitochondrial type sii. since then, these populations have been shown to be heterogeneous, some being infected by one wolbachia genetic variant only (wha), while others are infected simultaneously by wha and by another variant (wno) always found in association with wha. we have experimentally obtained two d. simulans strains only infected by the wno varian ...19958582608
wolbachia superinfections and the expression of cytoplasmic incompatibility.strains of drosophila simulans from riverside, california (dsr) and hawaii (dsh) harbour distinct strains of the cytoplasmic incompatibility microorganism wolbachia, resulting in the expression of bidirectional incompatibility when crossed. d. simulans lines carrying both of these (superinfected) wolbachia strains were generated by the transfer of infected dsh cytoplasm into dsr embryos by microinjection. the superinfected flies were unidirectionally incompatible with both dsr and dsh individual ...19958587875
pcr-based detection of wolbachia, cytoplasmic incompatibility microorganisms, infected in natural populations of laodelphax striatellus (homoptera: delphacidae) in central japan: has the distribution of wolbachia spread recently?cytoplasmic incompatibility is caused in various insects by intracellular infection with rickettsia-like microorganisms of the genus wolbachia. in japan laodelphax striatellus shows unidirectional cytoplasmic incompatibility between northeastern and southwestern populations. in this study, nine natural populations of l. striatellus collected from central japan, including the geographic boundary between the two cytotype populations, were analysed for wolbachia infection by pcr using primers speci ...19958825761
an improved microinjection protocol for the transfer of wolbachia pipientis between infected and uninfected strains of the flour beetle tribolium confusum.the lethality of halocarbon and other oils to hatching larvae of the flour beetle tribolium confusum limits existing microinjection protocols, because postinjection survivorship is only 5.6% of the eggs injected. we report the development of an oil-free protocol that improves survivorship fivefold. we used this protocol to transfect the cytoplasmic endosymbiont wolbachia pipientis from infected donor eggs to uninfected host eggs and observed reproductive incompatibility in 40% of the surviving, ...19968764685
contrasting levels of variability between cytoplasmic genomes and incompatibility types in the mosquito culex pipiens.reproductive incompatibilities called cytoplasmic incompatibilities are known to affect a large number of arthropod species and are mediated by wolbachia, a maternally transmitted microorganism. the crossing relationships between strains of potential hosts define their incompatibility types and it is generally assumed that differences between strains of wolbachia induce different crossing types. among all the described host species, the mosquito, culex pipiens, displays the greatest variability ...19979061971
molecular identification of a wolbachia endosymbiont in a tetranychus urticae strain (acari: tetranychidae).wolbachia, a maternally inherited bacterium, is involved in alterations of arthropod sexuality. reproductive incompatibilities are often observed in miles, but the existence of this microorganism in their cytoplasm has not yet been demonstrated. we identified the presence of wolbachia in a strain of the spider mite tetranychus urticae based on the amplification and sequencing of part of the 16s rdna and ftsz genes. in order to establish the phylogenetic relationships between wolbachia found in t ...19968799741
parthenogenesis-inducing microorganisms in aphytis (hymenoptera: aphelinidae).production of males in uniparental lines of two species in the parasitic wasp genus aphytis was induced by rifampicin, and male sexual functioning was determined. wolbachia-specific 16s rdna primers were used in a pcr in order to: (1) assess correlation between thelytokous reproduction and the presence of wolbachia; (2) detect the loss of wolbachia dna in uniparental a. lingnanensis following antibiotic treatments, with or without the presence of a host; and (3) clone and sequence part of the wo ...19958589844
wolbachia-induced delay of paternal chromatin condensation does not prevent maternal chromosomes from entering anaphase in incompatible crosses of drosophila simulans.the behavior of parental chromosomes during the first mitosis of drosophila simulans zygotes obtained from unidirectional incompatible crosses is described and it is demonstrated that the condensation of parental chromatin complements was asynchronous. the timing of paternal chromatin condensation appeared to be delayed in these embryos, so that condensed maternal chromosomes and entangled prophase-like paternal fibers congressed in the equatorial plane of the first metaphase spindle. at anaphas ...19979044057
the role of wolbachia bacteria in reproductive incompatibilities and hybrid zones of diabrotica beetles and gryllus crickets.a rickettsial bacterium in the genus wolbachia is the cause of a unidirectional reproductive incompatibility observed between two major beetle pests of maize, the western corn rootworm, diabrotica virgifera virgifera, and the mexican corn rootworm, d. v. zeae. these subspecies are allopatric except for two known regions of sympatry in texas and mexico. we demonstrate that populations of d. v. virgifera, with the exception of two populations in southern arizona, are infected with a strain of wolb ...19979326628
"curing" wolbachia infections in culex pipiens. 1975808618
wolbachia infection and cytoplasmic incompatibility in drosophila species.forty-one stocks from 30 drosophila species were surveyed for wolbachia infection using pcr technology. d. sechellia and two strains of d. auraria were found to be infected and were tested for the expression of cytoplasmic incompatibility, along with d. ananassae and d. melanogaster strains, which are already known to be infected. d. ananassae and d. melanogaster show levels of incompatibility up to 25%, while d. auraria and d. sechellia exhibit levels of egg mortality approximately 60%. a dot-b ...19968913750
cloning and characterization of a gene encoding the major surface protein of the bacterial endosymbiont wolbachia pipientis.the maternally inherited intracellular symbiont wolbachia pipientis is well known for inducing a variety of reproductive abnormalities in the diverse arthropod hosts it infects. it has been implicated in causing cytoplasmic incompatibility, parthenogenesis, and the feminization of genetic males in different hosts. the molecular mechanisms by which this fastidious intracellular bacterium causes these reproductive and developmental abnormalities have not yet been determined. in this paper, we repo ...19989573188
phylogeny and potential transmission routes of midgut-associated endosymbionts of tsetse (diptera:glossinidae).many tsetse species (diptera: glossinidae) harbour two morphologically different intracellular endosymbiotic microorganisms associated with gut tissue: primary (p) and secondary (s) endosymbionts. the p-endosymbionts of tsetse (wigglesworthia glossinidia) are sequestered in specialized epithelial cells, bacteriocytes, which form a structure (bacteriome) in the anterior portion of the gut. phylogenetic characterization of p-endsymbionts from the three subgenera of genus glossina has shown that th ...19979099582
molecular evidence for single wolbachia infections among geographic strains of the flour beetle tribolium confusum.infections with the rickettsial microorganism wolbachia are cytoplasmically inherited and occur in a wide range of insect species and several other arthropods. wolbachia infection often results in unidirectional cytoplasmic incompatibility (ci): crosses between infected males and uninfected females are incompatible and show a reduction of progeny or complete inviability. unidirectional ci can also occur when males harbouring two incompatible wolbachia strains are crossed with females infected wi ...19979263471
wolbachia, normally a symbiont of drosophila, can be virulent, causing degeneration and early death.wolbachia, a maternally transmitted microorganism of the rickettsial family, is known to cause cytoplasmic incompatibility, parthenogenesis, or feminization in various insect species. the bacterium-host relationship is usually symbiotic: incompatibility between infected males and uninfected females can enhance reproductive isolation and evolution, whereas the other mechanisms enhance progeny production. we have discovered a variant wolbachia carried by drosophila melanogaster in which this cozy ...19979380712
phylogenetic characterization of two transovarially transmitted endosymbionts of the bedbug cimex lectularius (heteroptera:cimicidae).two different inherited bacterial symbionts from ovary tissue of the bedbug cimex lectularius were characterized by gene amplification and sequencing analysis of their 16s rdna gene. the first bacterium belongs to the wolbachia subgroup of the alpha-proteobacteria, the second is a member of the gamma-subdivision, and is closely related to the bacterial parasite of the leafhopper euscelidius variegatus (bev) which was shown to be capable of transovarial transmission. the high similarity (> 97%) b ...19979272448
characterization of an endosymbiont infecting wood ticks, dermacentor andersoni, as a member of the genus francisella.a microorganism (dermacantor andersoni symbiont [das]) infecting rocky mountain wood ticks (d. andersoni) collected in the bitterroot mountains of western montana was characterized as an endosymbiont belonging to the genus francisella. previously described as wolbachia like, the organism's dna was amplified from both naturally infected tick ovarial tissues and vero cell cultures by pcr assay with primer sets derived from eubacterial 16s ribosomal dna (rdna) and francisella membrane protein genes ...19979327558
endosymbionts of ticks and their relationship to wolbachia spp. and tick-borne pathogens of humans and animals.the presence, internal distribution, and phylogenetic position of endosymbiotic bacteria from four species of specific-pathogen-free ticks were studied. these included the hard ticks ixodes scapularis (the black-legged tick), rhipicephalus sanguineus (the brown dog tick), and haemaphysalis longicornis and the african soft tick ornithodoros moubata. pcr assays for bacteria, using two sets of general primers for eubacterial 16s and 23s rrna genes (rdnas) and seven sets of specific primers for wolb ...19979327557
western blotting analysis of heat shock proteins of rickettsiales and other eubacteria.heat shock proteins (hsp) of four rickettsia species, three bartonella species, two ehrlichia species, orientia tsutsugamushi and seventeen other eubacterial species were characterized by the enhanced chemiluminescence western blotting (wb) technique with antibodies raised against recombinant hsp from escherichia coli and purified groes from r. typhi. although e. coli dnak and groel have epitopes that are highly conserved among the homologous proteins found in rickettsia, ehrlichia, o. tsutsugam ...19989809424
distribution of parthenogenesis-inducing symbionts in ovaries and eggs of aphytis (hymentoptera: aphelinidae).in parasitic hymenoptera, severe sex ratio distortions are sometimes associated with the presence of symbiotic microorganisms. symbiont-induced uniparental reproduction is found in several species of the genus aphytis and is suspected in others. these intracellular bacteria (called wolbachia) reside within the egg cytoplasm. in order to follow their vertical transmission, the distribution pattern of the symbionts in ovaries and eggs of two uniparental lines (a. lingnanensis and a. yanonensis) wa ...19989405738
phylogenetically distant intracellular symbionts in termites.cockroaches are known to harbour intracellular bacteria in specialised cells (mycetocytes, or bacteriocytes) of the fat body. in termites, mycetocyte bacteria have been observed only in mastotermes darwiniensis. these symbionts are thought to have originated from a bacterium that infected an ancestor common to cockroaches and termites. thus, loss of the infection should have occurred during evolution in all termite lineages, with the exception of that leading to m. darwiniensis. one might suspec ...19979419851
population dynamics of the wolbachia infection causing cytoplasmic incompatibility in drosophila melanogaster.field populations of drosophila melanogaster are often infected with wolbachia, a vertically transmitted microorganism. under laboratory conditions the infection causes partial incompatibility in crosses between infected males and uninfected females. here we examine factors influencing the distribution of the infection in natural populations. we show that the level of incompatibility under field conditions was much weaker than in the laboratory. the infection was not transmitted with complete fi ...19989475734
ultrastructural differentiation of the genogroups in the genus ehrlichia.ultrastructural characteristics of 15 strains and isolates of ehrlichiae belonging to three genogroups, or clades of genetically related organisms united in the genera ehrlichia, cowdria, anaplasma, neorickettsia and a strain of wolbachia pipientis which represents a fourth genogroup in this cluster of species, were studied in continuous cell culture or in vivo: e. canis (oklahoma strain and vhe isolate), e. muris (as 145), e. chaffeensis (arkansas, 91he17 and sapulpa), human granulocytic ehrlic ...19989511829
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 ...199910030026
rescuing wolbachia have been overlooked. 19989495337
overcoming cytoplasmic incompatibility in drosophila.the endocellular microbe wolbachia pipientis infects a wide variety of invertebrate species, in which its presence is closely linked to a form of reproductive failure termed cytoplasmic incompatibility (ci). ci renders infected males unable to father offspring when mated to uninfected females. because ci can dramatically affect fitness in natural populations, mechanisms that abate ci can have equally large impacts on fitness. we have discovered that repeated copulation by wolbachia-infected male ...19989523438
analysis of wolbachia protein synthesis in drosophila in vivo.intracellular wolbachia infections are extremely common in arthropods and exert profound control over the reproductive biology of the host. however, very little is known about the underlying molecular mechanisms which mediate these interactions with the host. we examined protein synthesis by wolbachia in a drosophila host in vivo by selective metabolic labelling of prokaryotic proteins and subsequent analysis by 1d and 2d gel electrophoresis. using this method we could identify the major protein ...19989535156
screening mollusks for wolbachia infection.we screened 38 species of mollusks for infection by wolbachia, a bacterium that is a common endosymbiont in arthropods, where it induces alterations in reproduction. using a pcr assay, we could not detect the symbiont in any of the samples, indicating that, in mollusks, it might be absent.19989538033
allozyme polymorphism and geographic variation in the small brown planthopper, laodelphax striatellus (homoptera: delphacidae).the small brown planthopper, laodelphax striatellus, immigrates annually into japan over the east china sea from the asian mainland. it is not known whether this long-distance dispersal has any effect on the genetic structure of japanese l. striatellus populations. the dispersal of l. striatellus is suspected to be relevant to the population dynamics of infection with the parasitic bacterium wolbachia, which causes cytoplasmic incompatibility in l. striatellus. wolbachia infection has spread wit ...19979559095
effects of a and b wolbachia and host genotype on interspecies cytoplasmic incompatibility in nasonia.wolbachia endosymbionts cause postmating reproductive isolation between the sibling species nasonia vitripennis and n. giraulti. most nasonia are doubly infected with a representative from each of the two major wolbachia groups (a and b). this study investigates the role of single (a or b) and double (a and b) wolbachia infections in interspecies cytoplasmic incompatibility (ci) and host genomic influences on the incompatibility phenotype. results show that the single a wolbachia harbored in n. ...19989560398
wolbachia as a possible means of driving genes into populations.cytoplasmic incompatibility consists of sterility in cross matings, the crossing type being maternally inherited. it can be explained by the action of wolbachia symbionts which are transmitted through the egg cytoplasm and leave an imprint on the sperm which prevents it fertilizing unless it is 'rescued' by the action of the same type of wolbachia in the egg. thus matings between infected males and uninfected females are sterile, but the reciprocal matings are fertile. hence uninfected females a ...19989695115
horizontal transfer of parasitic sex ratio distorters between crustacean hosts.parasitic sex distorters were artificially transferred within and between crustacean host species in order to study the effects of parasitism on host fitness and sex determination and to investigate parasite host specificity. implantation of nosema sp. to uninfected strains of its gammarus duebeni host resulted in an active parasite infection in the gonad of recipient females and subsequent transovarial parasite transmission. the young of artificially infected females were feminized by the paras ...19989695096
phylogeny and pcr-based classification of wolbachia strains using wsp gene sequences.wolbachia are a group of intracellular inherited bacteria that 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. while it is known that the bacterial strains responsible for these different host phenotypes form a single clade within the alpha-proteobacteria, until now it has not been possible to resolve the evolutionary relationships between different wol ...19989569669
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 ...199910413661
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 ...199910380108
reduced variation in drosophila simulans mitochondrial dna.we investigated the evolutionary dynamics of infection of a drosophila simulans population by a maternally inherited insect bacterial parasite, wolbachia, by analyzing nucleotide variability in three regions of the mitochondrial genome in four infected and 35 uninfected lines. mitochondrial variability is significantly reduced compared to a noncoding region of a nuclear-encoded gene in both uninfected and pooled samples of flies, indicating a sweep of genetic variation. the selective sweep of mi ...19968978041
evidence for widespread wolbachia infection in isopod crustaceans: molecular identification and host feminization.wolbachia are maternally inherited, intracellular, alpha proteobacteria that infect a wide range of arthropods. they cause three kinds of reproductive alterations in their hosts: cytoplasmic incompatibility, parthenogenesis and feminization. there have been many studies of the distribution of wolbachia in arthropods, but very few crustacean species are known to be infected. we investigated the prevalence of wolbachia in 85 species from five crustacean orders. twenty-two isopod species were found ...19989684374
birefringent crystals and abdominal discoloration in the predatory mite phytoseiulus persimilis (acari: phytoseiidae)in response to grower complaints of poor performance of phytoseiulus persimilis, mites from 14 commercial insectaries and research colonies were examined for pathogens. some were found to have abdominal discolorations, manifested initially as two white stripes along the dorsal sides of the body within the malpighian tubules. advanced signs appeared as a large, centrally located, white spot or u-shaped discoloration in the distal opisthosoma within the rectum/anal atrium. white material often acc ...19979056458
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.199910419978
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.199910390640
widespread occurrence of the micro-organism wolbachia in ants.for more than 20 years, sex allocation in hymenopteran societies has been a major topic in insect sociobiology. a recurring idea was that relatedness asymmetrics arising from their haplodiploid sex determination system would lead to various parent-offspring conflicts over optimal reproduction. a possible weakness of existing theory is that only interests of nuclear genes are properly accounted for. yet, a diversity of maternally transmitted elements manipulate the reproduction of their host in m ...19989721689
phylogenetic analysis of parthenogenesis-inducing wolbachia in the genus aphytis (hymenoptera: aphelinidae).parthenogenesis-inducing intracellular bacteria of the genus wolbachia are found in a variety of parasitoid wasp genera. the presence of wolbachia in the uniparental aphytis species a. lingnanensis compere, a. diaspidis (howard), a. chilensis howard, and a. chrysomphali (mercet) was tested using primers specific for the ftsz gene. the symbiont was detected in all of these species. wolbachia ftsz genes that were sequenced from the four hosts show a high degree of similarity. both the pcr with spe ...19989723877
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 ...199910469257
wolbachia in two insect host-parasitoid communities.wolbachia form a group of intracellular bacteria that alter reproduction in their arthropod hosts. two major phylogenetic subdivisions (a and b) of wolbachia occur. using a polymerase chain reaction assay we surveyed for the a and b group wolbachia in 82 insect species from two temperate host-parasitoid communities (food webs) and a general collection of lepidoptera caught at a light trap. one host-parasitoid community was based around leaf-mining lepidoptera, and the other around aphids. we fou ...19989819901
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 ...199910555290
concordant evolution of a symbiont with its host insect species: molecular phylogeny of genus glossina and its bacteriome-associated endosymbiont, wigglesworthia glossinidia.many arthropods with restricted diets rely on symbiotic associations for full nutrition and fecundity. tsetse flies (diptera: glossinidae) harbor three symbiotic organisms in addition to the parasitic african trypanosomes they transmit. two of these microorganisms reside in different gut cells, while the third organism is harbored in reproductive tissues and belongs to the genus wolbachia. the primary symbiont (genus wigglesworthia glossinidia) lives in differentiated epithelial cells (bacterioc ...19999873076
Displaying items 1 - 100 of 1360