Frydman Horacio M, Li Jennifer M, Robson Drew N, Wieschaus Eric
Howard Hughes Medical Institute, Princeton University, Princeton, New Jersey 08540, USA.
Nature. 2006 May 25;441(7092):509-12. doi: 10.1038/nature04756.
Wolbachia are intracellular bacteria found in the reproductive tissue of all major groups of arthropods. They are transmitted vertically from the female hosts to their offspring, in a pattern analogous to mitochondria inheritance. But Wolbachia phylogeny does not parallel that of the host, indicating that horizontal infectious transmission must also occur. Insect parasitoids are considered the most likely vectors, but the mechanism for horizontal transfer is largely unknown. Here we show that newly introduced Wolbachia cross several tissues and infect the germline of the adult Drosophila melanogaster female. Through investigation of bacterial migration patterns during the course of infection, we found that Wolbachia reach the germline through the somatic stem cell niche in the D. melanogaster germarium. In addition, our data suggest that Wolbachia are highly abundant in the somatic stem cell niche of long-term infected hosts, implying that this location may also contribute to efficient vertical transmission. This is, to our knowledge, the first report of an intracellular parasite displaying tropism for a stem cell niche.
沃尔巴克氏体是在所有主要节肢动物类群的生殖组织中发现的细胞内细菌。它们以类似于线粒体遗传的模式从雌性宿主垂直传播到其后代。但沃尔巴克氏体的系统发育与宿主并不平行，这表明水平感染传播也必定会发生。昆虫寄生蜂被认为是最有可能的传播媒介，但水平转移的机制在很大程度上尚不清楚。在这里，我们表明新引入的沃尔巴克氏体穿过多个组织并感染成年黑腹果蝇雌性的生殖系。通过研究感染过程中的细菌迁移模式，我们发现沃尔巴克氏体通过黑腹果蝇卵巢管中的体细胞干细胞生态位到达生殖系。此外，我们的数据表明，在长期感染宿主的体细胞干细胞生态位中，沃尔巴克氏体数量非常丰富，这意味着该位置也可能有助于高效的垂直传播。据我们所知，这是关于一种细胞内寄生虫对干细胞生态位具有嗜性的首次报道。
