External layers of Rickettsia prowazekii and Rickettsia rickettsii: occurrence of a slime layer.
AUTOR(ES)
Silverman, D J
RESUMO
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.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=422141Documentos Relacionados
- Experimental infection of dogs with a Brazilian strain of Rickettsia rickettsii: clinical and laboratory findings
- Comparative ultrastructural study on the cell envelopes of Rickettsia prowazekii, Rickettsia rickettsii, and Rickettsia tsutsugamushi.
- Expression of the gene encoding the 17-kilodalton antigen from Rickettsia rickettsii: transcription and posttranslational modification.
- In Vitro Activities of Telithromycin (HMR 3647) against Rickettsia rickettsii, Rickettsia conorii, Rickettsia africae, Rickettsia typhi, Rickettsia prowazekii, Coxiella burnetii, Bartonella henselae, Bartonella quintana, Bartonella bacilliformis, and Ehrlichia chaffeensis
- Characterization of the gene encoding the protective paracrystalline-surface-layer protein of Rickettsia prowazekii: presence of a truncated identical homolog in Rickettsia typhi.