EVOLUTIONARY AND CELLH BIOLOGICAL STUDIES ON Wolbachia, ENDOCELLULAR SYMBIOTIC MICROORGANISMS

沃尔巴克氏菌是一组遗传的类立克次体细菌，发现于多种节肢动物中，可引起宿主的各种生殖变化，包括雌性化、孤雌生殖和细胞质不亲和性。我们检测了三种飞蛾的沃尔巴克氏菌感染情况，这三种飞蛾分别是：印度粉蛾Plodia interpotella、杏仁蛾Ephstia cautea和地中海面粉蛾Ephstia kuehniella。我们检测到了卡氏肠杆菌和两株库尼埃希氏菌的感染，其中一株来自土浦市，另一株来自横滨市。点状巴氏杆菌中未检出沃尔巴克氏菌。根据编码沃尔巴克氏菌细胞表面蛋白的wsp基因序列，推测了霍氏菌和库尼氏埃希氏菌的系统发育位置。我们还进行了交叉实验，以检查细胞质不亲和性。结果表明，黑纹伊蚊体内的沃尔巴克氏菌引起细胞质完全不亲和：感染的雄虫与未感染的雌虫杂交，未观察到卵孵化。土浦株和横滨株均表现出部分胞质不亲和性，但两株间的胞质不亲和性存在显著差异。土浦品系和横滨品系不亲和杂交的卵孵化率分别为60.8%和16.9%。

Wolbachia are a group of inherited Rickettia-like bacteria found in a number of arthropods and known to cause various reproductive alterations of their hosts, including feminization, parthenogenesis and cytoplasmic incompatibility. We examined Wolbachia infection in three species of moths belonging to the sub-family Phycitinae, the Indian meal moth Plodia interpunctella, the almond moth Ephestia cautella and the Mediterranean flour moth Ephestia kuehniella. We detected infections in E. cautella and two strains of E. kuehniella, one from Tsuchiura city and the other from Yokohama city. Wolbachia was not detected in P. interpunctella. The phylogenetic positions of Wolbachia harbored by E. cautella and E. kuehniella were estimated based on the sequences of the wsp gene that encodes a Wolbachia cell surface protein. We also performed crossing experiments to examine cytoplasmic incompatibility. It was shown that Wolbachia in E. cautella caused complete cytoplasmic incompatibility : no egg-hatch was observed in the cross between infected males and uninfected females. Both Tsuchiura and Yokohama strains of E. kuehniella showed partial cytoplasmic incompatibility, but the levels were significantly different between the two strains. The rates of egg hatch in the incompatible crosses within Tsuchiura and Yokohama strains were 60.8% and 16.9%, respectively.