Experimental analysis of symbiosis of Orientia tsutsugamushi and Leptotrombidium

为了了解恙虫病东方体Gilliam、Karp、Kato、川崎、Kuroki、Shimokoshi和Ikeda 7株的系统发育关系，对恙虫病东方体11 kDa、22 kDa、46 kDa、56 kDa、60 kDa蛋白基因、16 SrRNA基因和23 S-5SrRNA内转录序列（ITS）进行了序列测定。7个菌株之间的平均同源性为79.7 ~ 99.3%，每个序列有21个组合。16 SrRA基因和胞质蛋白（11 kDa和60 kDa）基因的变异较小。其他蛋白质和ITS序列在菌株间表现出相当大的差异。其他蛋白质则定位于微生物的外膜，说明环境选择压力对0。恙虫病。这导致抗原性变异为0。与恙虫病病毒的同源性最低的56 kDa蛋白的结构有关。根据同源性推断的菌株系统发育关系因基因的不同而不同，这表明从少量基因进行系统发育分析是困难的。然而，Shomokoshi，总是表现出较低的同源性，其他菌株，这表明在该微生物的系统发育分离的位置。ITS，这是经常分析，以了解细菌的同源性，也显示了很大的差异菌株之间，但这个序列太短，绘制一个显着的系统发育树。我们正在通过随机鸟枪策略对池田的整个基因组进行测序，但重复的序列阻止了完成。当全基因组序列出现时，通过比较假基因和基因组结构来分析遗传学。

We sequenced 11kDa, 22kDa, 46kDa, 56kDa, 60kDa protein genes, 16SrRNA gene and 23S-5SrRNA internal transcribed sequence (ITS) of Orientia tsutsugamushi to know the phylogenetic relationship of seven strains, Gilliam, Karp, Kato, Kawasaki, Kuroki, Shimokoshi and Ikeda. The average homology among the seven strains, 21 combinations in each sequence, varied from 79.7 to 99.3%. The genes of 16SrRA and cytoplasmic protein (11 kDa and 60 kDa) genes vary a little. The sequences of the other proteins and ITS showed considerable variation among the strains. The other proteins locate in the outer membrane of the microorganism, suggesting that selection pressure of the circumstance affected on the surface structure of 0. tsutsugamushi. This causes the antigenic variation of 0. tsutsugamushi, which depends on structure of the 56kDa protein, the sequence of which showed the lowest homology among the proteins. Phylogenetic relations of the strains deduced from the homologies were different each other depending on the genes, suggesting the difficulty in phylogenetic analysis from a small number of genes. Shomokoshi, however, always showed low homology to the other strains, suggesting separated position in the pylogeny of this microorganism. The ITS, that is frequently analyzed to know bacterial aphlogeny, also showed great variation among the strains, but this sequence was too short to draw a significant phylogenetic tree. We are sequencing the whole genome of Ikeda by random shotgun strategy, but repeated sequences prevent from completion. When the whole genome sequence appears, the phylogeny would be analyzed by comparison of psuedogenes and structure of the genome.