| spiroplasmas: infectious agents of plants, arthropods and vertebrates. | the spiroplasmas are mollicutes characterized by motility and helical morphology. they were discovered through studies on corn stunt and citrus stubborn diseases. the stubborn agent was the first mollicute of plant origin to be obtained in culture and the first cultured mollicute to possess a helical morphology. the citrus pathogen has been known as spiroplasma citri since 1973. the corn stunt agent was cultured in 1975 and fully characterized as spiroplasma kunkelii by 1986. the third and only ... | 1997 | 9286068 |
| spiroplasma poulsonii sp. nov., a new species associated with male-lethality in drosophila willistoni, a neotropical species of fruit fly. | progenies from some wild-caught females of drosophila willistoni and three other sibling species are entirely female. the proclivity for production of unisexual female progeny by these flies was named the sex ratio (sr) trait and was originally thought to be genetic. however, experiments in the laboratory of donald f. poulson in the early 1960s demonstrated that this 'trait' was vertically transmitted and infectious, in that it could be artificially transferred by injection from infected females ... | 1999 | 10319483 |
| hidden from the host: spiroplasma bacteria infecting drosophila do not cause an immune response, but are suppressed by ectopic immune activation. | insects and other arthropods have an effective innate immune system that can clear infections with bacteria and other microorganisms. despite this ability, one group of bacteria, the spiroplasmas, survive unharmed within the haemolymph of a wide range of arthropod hosts. we investigated the interaction between one member of this clade, a relative of spiroplasma poulsonii, and the immune system of its drosophila host. expression of antimicrobial genes in spiroplasma-infected flies did not differ ... | 2003 | 12542640 |
| a functional dosage compensation complex required for male killing in drosophila. | bacteria that selectively kill males ("male-killers") were first characterized more than 50 years ago in drosophila and have proved to be common in insects. however, the mechanism by which sex specificity of virulence is achieved has remained unknown. we tested the ability of spiroplasma poulsonii to kill drosophila melanogaster males carrying mutations in genes that encode the dosage compensation complex. the bacterium failed to kill males lacking any of the five protein components of the compl ... | 2005 | 15746426 |
| interspecific transmission of endosymbiotic spiroplasma by mites. | the occurrence of closely related strains of maternally transmitted endosymbionts in distantly related insect species indicates that these infections can colonize new host species by lateral transfer, although the mechanisms by which this occurs are unknown. we investigated whether ectoparasitic mites, which feed on insect haemolymph, can serve as interspecific vectors of spiroplasma poulsonii, a male-killing endosymbiont of drosophila. using spiroplasma-specific primers for pcr, we found that m ... | 2007 | 17443956 |
| spiroplasma and host immunity: activation of humoral immune responses increases endosymbiont load and susceptibility to certain gram-negative bacterial pathogens in drosophila melanogaster. | spiroplasma poulsonii and its relatives are facultative, vertically transmitted endosymbionts harboured by several drosophila species. their long-term survival requires not only evasion of host immunity, but also that spiroplasma does not have a net detrimental effect on host fitness. these requirements provide the central framework for interactions between host and endosymbiont. we use drosophila melaogaster as a model to unravel aspects of the mechanistic basis of endosymbiont-host immune inte ... | 2011 | 21740495 |
| insect endosymbiont proliferation is limited by lipid availability. | spiroplasma poulsonii is a maternally transmitted bacterial endosymbiont that is naturally associated with drosophila melanogaster. s. poulsonii resides extracellularly in the hemolymph, where it must acquire metabolites to sustain proliferation. in this study, we find that spiroplasma proliferation specifically depletes host hemolymph diacylglyceride, the major lipid class transported by the lipoprotein, lpp. rnai-mediated knockdown of lpp expression, which reduces the amount of circulating lip ... | 2014 | 25027439 |
| cell division by longitudinal scission in the insect endosymbiont spiroplasma poulsonii. | spiroplasma bacteria are highly motile bacteria with no cell wall and a helical morphology. this clade includes many vertically transmitted insect endosymbionts, including spiroplasma poulsonii, a natural endosymbiont of drosophila melanogaster s. poulsonii bacteria are mainly found in the hemolymph of infected female flies and exhibit efficient vertical transmission from mother to offspring. as is the case for many facultative endosymbionts, s. poulsonii can manipulate the reproduction of its h ... | 2016 | 27460796 |
| the role of lipid competition for endosymbiont-mediated protection against parasitoid wasps in drosophila. | insects commonly harbor facultative bacterial endosymbionts, such as wolbachia and spiroplasma species, that are vertically transmitted from mothers to their offspring. these endosymbiontic bacteria increase their propagation by manipulating host reproduction or by protecting their hosts against natural enemies. while an increasing number of studies have reported endosymbiont-mediated protection, little is known about the mechanisms underlying this protection. here, we analyze the mechanisms und ... | 2016 | 27406568 |
| genome sequence of the drosophila melanogaster male-killing spiroplasma strain msro endosymbiont. | spiroplasmas are helical and motile members of a cell wall-less eubacterial group called mollicutes. although all spiroplasmas are associated with arthropods, they exhibit great diversity with respect to both their modes of transmission and their effects on their hosts; ranging from horizontally transmitted pathogens and commensals to endosymbionts that are transmitted transovarially (i.e., from mother to offspring). here we provide the first genome sequence, along with proteomic validation, of ... | 2015 | 25827421 |
| novel strain of spiroplasma found in flower bugs of the genus orius (hemiptera: anthocoridae): transovarial transmission, coexistence with wolbachia and varied population density. | spiroplasma, a group of small, wall-less, helical, and motile bacteria belonging to the mollicutes, contains species with diverse life histories. to date, all the spiroplasma strains that are known to be transmitted vertically in arthropod lineages belong to either the spiroplasma ixodetis group or the spiroplasma poulsonii group. here, we found that a unique strain of spiroplasma vertically transmitted in predatory flower bugs of the genus orius belongs to the spiroplasma insolitum group, which ... | 2014 | 24337178 |
| male killing spiroplasma protects drosophila melanogaster against two parasitoid wasps. | maternally transmitted associations between endosymbiotic bacteria and insects are diverse and widespread in nature. owing to imperfect vertical transmission, many heritable microbes have evolved compensational mechanisms to enhance their persistence in host lineages, such as manipulating host reproduction and conferring fitness benefits to host. symbiont-mediated defense against natural enemies of hosts is increasingly recognized as an important mechanism by which endosymbionts enhance host fit ... | 2014 | 24281548 |
| vertical transmission of a drosophila endosymbiont via cooption of the yolk transport and internalization machinery. | spiroplasma is a diverse bacterial clade that includes many vertically transmitted insect endosymbionts, including spiroplasma poulsonii, a natural endosymbiont of drosophila melanogaster. these bacteria persist in the hemolymph of their adult host and exhibit efficient vertical transmission from mother to offspring. in this study, we analyzed the mechanism that underlies their vertical transmission, and here we provide strong evidence that these bacteria use the yolk uptake machinery to coloniz ... | 2013 | 23462112 |