title: Ultrastructure of lipopolysaccharides of Yersinia enterocolitica, Salmonella typhimurium and Escherichia coli.
abstract: The fine structure of isolated lipopolysaccharides (LPS) from the rough and smooth form of an Yersinia enterocolitica strain (Ye 75 R/Ye 75 S) and from smooth forms of Salmonella typhimurium (S 1010) and Escherichia coli (Essen) were examined electron-microscopically by negative staining. Partial denaturation of LPS in Tris-buffer with acid and/or polymyxin B treatment revealed a common structure of strandlike LPS. Electron-microscopically, LPS-strands were found to consist of two identical sub-strands which form a double helix. High resolution electron microscopy permitted the identification of a total of four longitudinal fibrils (diameter approximately 20 A); therefore, each sub-strand consists of two longitudinal fibrils. These results were correlated with those obtained with positive staining procedure and chemical fixation technique. The development of the "double-track"-profile of the outer membrane was interpreted to result from the projection of the helical longitudinal fibrils into the image plane.
mesh_terms: D004926:Escherichia coli / Q000032:analysis*; D008070:Lipopolysaccharides / Q000032:analysis* / Q000302:isolation & purification; D008854:Microscopy, Electron; D008968:Molecular Conformation; D011113:Polymyxins / Q000494:pharmacology; D011135:Polysaccharides, Bacterial / Q000032:analysis* / Q000302:isolation & purification; D012486:Salmonella typhimurium / Q000032:analysis*; D015007:Yersinia / Q000032:analysis*
chemical_list: D008070:Lipopolysaccharides; D011113:Polymyxins; D011135:Polysaccharides, Bacterial