Susceptibility of ixodid ticks to Lyme disease borreliae : a search of the control molecules

蓖麻硬蜱种复合体的硬蜱充当属于疏螺旋体属的莱姆病螺旋体的载体。三个基因种，伯氏疏螺旋体、伽氏疏螺旋体和阿氏疏螺旋体，对人类是致病的;然而，有几种密切相关的微生物由其他硬蜱传播。通常，蜱物种充当某些疏螺旋体物种的载体。为了研究蜱和疏螺旋体之间的特异性关系，进行了以下实验。(1)实验感染疏螺旋体的几个不合适的蜱种透露，蜱的易感性涉及两个阶段（驱逐和许可的疏螺旋体）通过蜱的蜕皮过程。实验还表明，保留疏螺旋体的蜕皮蜱并不总是作为将疏螺旋体传播给脊椎动物的载体。(2)在套装中连续观察了疏螺旋体的定量和定性动态 ...更多信息 能蜱种类。疏螺旋体增殖滞育蜱后，采取血餐，然而，疏螺旋体的数量急剧下降后蜕皮。我发现蜱虫中肠里多余的疏螺旋体会从刚蜕皮的蜱虫的粪便中排出。蜕皮蜱体内剩余的疏螺旋体在饥饿期间没有增殖，并且未能保持对脊椎动物的感染性。然而，当蜱虫被允许以新的脊椎动物宿主为食时，传染性又恢复了。疏螺旋体在摄食过程中表达部分外表面蛋白。(3)我假设控制蜱易感性的分子是疏螺旋体上的osp分子。尽管进行了将osp质粒转染到异源疏螺旋体物种的实验，但寻找合适的转染条件的试验失败。(4)在日本两个地区北海道和长野进行了蜱和疏螺旋体的比较遗传学研究。蜱和疏螺旋体DNA中的特征碱基替换表明地理隔离对蜱和疏螺旋体的卷积很重要。少

The ixodid ticks of the Ixodes ricinus species complex serve as vectors for Lyme disease spirochetes belonging to the genus Borrelia. The three genospecies, Borrelia burgdorferi, Borrelia garinii, and Borrelia afzelii, are pathogenic for humans ; however, there are several closely related microbes which are transmitted by other ixodid ticks. In general, a tick species serves as a vector for a certain Borrelia species. In order to investigate the specific relationship between ticks and borreliae, the following experiments were conducted. (1) Experimental infection of borreliae to several unsuitable tick species revealed that the susceptibility of ticks involves two phases (expulsion and permission of borreliae) through the molting process of ticks. The experiments also demonstrated that molted ticks retaining borreliae do not always serve as a vector for transmitting borreliae to vertebrates. (2) The quantitative and qualitative dynamics of borreliae were sequentially observed in a suit … More able tick species. Borreliae proliferated in diapausing ticks after taking blood meals ; however, the number of borreliae was dramatically decreased after molting. I found that excess borreliae in tick midgut discharged in feces of newly molted ticks. The remaining borreliae within the molted ticks did not proliferate through the period of starvation and failed to maintain the infectivity to vertebrates. However, the infectivity revived when the ticks were allowed to feed on new vertebrate host. During the feeding process, a part of outer surface proteins (osp) was expressed on borreliae. (3) I postulated that the control molecules for the susceptibility of ticks are the osp molecules on borreliae. Although the experiment for transfecting the osp plasmid to heterogenous Borrelia species was carried out, the trial to find an appropriate condition for transfection was failed. (4) The comparative genetic study on ticks and borreliae was conducted in two Japanese regions, Hokkaido and Nagano. The characteristic base substitution in DNAs of ticks and borreliae suggests that geographical isolation is important for convolution of ticks and borreliae. Less