Todd W J, Burgdorfer W, Wray G P
Infect Immun. 1983 Sep;41(3):1252-60. doi: 10.1128/iai.41.3.1252-1260.1983.
The ultrastructural appearance of the "halozone" formed at the interface between the spotted fever agent Rickettsia rickettsii and the cytoplasm of persistently infected cultured vole cells (Microtus pennsylvanicus) was studied by transmission electron microscopy. In sections of epoxy-embedded specimens stained with uranyl acetate and lead citrate, the halozone appeared clear and devoid of ultrastructural features. However, when unembedded preparations of whole infected cells were examined at 1,000 kV, fine structural features were observed within the halozone. These features, associated with the rickettsial outer membrane, were more clearly detectable when the infected cells were extracted with the detergent Triton X-100 before fixation. Under such conditions, long extensions of the rickettsial outer membrane, microfilament-like structures attached to that membrane, and extensive attachments between adjacent rickettsiae were seen. The fine structural features within the rickettsial halozone were also seen at 75 kV when unembedded sections were prepared from polyethylene glycol-embedded specimens. Thus, epoxy-embedding medium obscures the fine structural features within the halozone surrounding the rickettsiae in infected cells.
通过透射电子显微镜研究了在斑点热病原体立氏立克次体与持续感染的培养田鼠细胞（宾夕法尼亚田鼠）细胞质之间的界面处形成的“晕环”的超微结构外观。在用醋酸铀和柠檬酸铅染色的环氧树脂包埋标本切片中，晕环显得清晰且没有超微结构特征。然而，当在1000 kV下检查未包埋的完整感染细胞制剂时，在晕环内观察到了精细结构特征。当在固定前用去污剂曲拉通X - 100提取感染细胞时，与立克次体外膜相关的这些特征更清晰可检测。在这种条件下，可以看到立克次体外膜的长延伸、附着在该膜上的微丝样结构以及相邻立克次体之间的广泛附着。当从聚乙二醇包埋的标本制备未包埋切片时，在75 kV下也能看到立克次体晕环内的精细结构特征。因此，环氧树脂包埋介质会掩盖感染细胞中立克次体周围晕环内的精细结构特征。
