Silverman D J, Wisseman C L, Waddell A D, Jones M
Infect Immun. 1978 Oct;22(1):233-46. doi: 10.1128/iai.22.1.233-246.1978.
Using a simple specific-antibody stabilization procedure on organisms gently liberated from their host cells, we have demonstrated by electron microscopy that Rickettsia prowazekii and Rickettsia rickettsii possess a coat of variable thickness, external to the outer leaflet of the cell wall and the structure designated by others as a "microcapsule," which corresponds most closely to the slime layer of certain other bacteria. Reactions in the methenamine silver and ruthenium red staining procedures and the failure to be visualized by standard procedures suggest that the slime layer is largely polysaccharide in nature. It is postulated that this slime layer accounts in large part for the large, electron-lucent, halo-like zone which is found by electron microscopy to surround organisms of the typhus and spotted fever groups in the cytoplasm of their host cells, that it may be the locus of some major group-specific antigens, and that it may function as an antiphagocytic mechanism, as an aid for attachment of rickettsiae to potential host cells, or both. Moreover, because the attenuated E strain of R. prowazekii has been shown to possess a substantial slime layer, the basis for attenuation is not likely to be a simple smooth-to-rough variation.
通过对从宿主细胞中温和释放出来的生物体采用一种简单的特异性抗体稳定化程序，我们利用电子显微镜证明，普氏立克次体和立氏立克次体在细胞壁外小叶以及其他人称为“微荚膜”的结构外部具有一层厚度可变的包膜，这与某些其他细菌的黏液层最为相似。六胺银和钌红染色程序中的反应以及无法通过标准程序观察到，表明黏液层在很大程度上是多糖性质的。据推测，这层黏液层在很大程度上解释了在电子显微镜下发现的围绕宿主细胞胞质中斑疹伤寒群和斑点热群生物体的大的、电子透明的、晕状区域，它可能是一些主要群特异性抗原的所在部位，并且它可能作为一种抗吞噬机制，作为立克次体附着于潜在宿主细胞的辅助手段，或者兼而有之。此外，由于已证明普氏立克次体的减毒E菌株具有大量黏液层，减毒的基础不太可能是简单的光滑到粗糙的变异。
