Research in Medicine

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Zotero  

Nayebi M, Kohan P. Comparison of Aerobic Sporadic Bacilli Structure with Electron Microscopy. Research in Medicine 1977; 5 (3) :234-247
URL: http://pejouhesh.sbmu.ac.ir/article-1-2761-en.html

I. The existence of differences and similarities in the sur- 4.
face features not only of different organisms or groups but also within given species has been demonstrated by a variety of techniques.

2. The different reactions of various organisms to the Gram stain might well be taken as one piece of evidence, the use of the electron microscop and associated prepa­rative techniques (including direct shadows, thin sec­tions, negative stains, and freeze-etches) provided clear indications and details for such variations.

3. Many of these preparative procedures when used alo­ne, however, do not provide adequate views, and the­reby sufficient information, to permit the desired com­prehension of the three dimensional nature of the cell surface.

 Direct shadows or the preparation of carbon replicas by the use of metals of fine grain (e.g., platinum-car­bon) afford the opportunity to determine the charac­teristics of cell surfaces and to provide cleares under­standing of the nature of such surfaces than is possible with negative staining. It is thus possible to observe, for example, not only gross morphological features but also globular or meshlike surfaces with these tech­niques; clearly, however, only exposed surfaces can be viewed. When spores of B. polymyxa and B. fastidiosus are compared by means of the carbon replica the utility of the freeze-etching approach, particularly for analysis of surface structures and their component lay­ers, becomes readily appeant.