The cell wall structure of Selenomonas ruminantium

Abstract

The cell wall structure of Selenomonas ruminantium subsp. lactilytica Str GA192 and subsp. ruminantium Str PC18 was examined. Whole cell walls of strain GA192 contained: - 11% total carbohydrate; 1% phosphorus; rhamnose; fucose; mannose; glucose; galactose; glucosamine; galactosamine; muramic acid; and two unidentified amino sugars; while Str PC18 walls contained 10% total carbohydrate; 0.9% phosphorus; mannose; glucose; galactose; glucosamine; galactosamine; muramic acid and two unidentified amino sugars. The peptidoglycan layer of Str GA192 was purified by extraction with sodium dodecyl sulphate and phenol. It contained: muramic acid; glucosamine; alanine; glutamic acid and diaminopimelic acid; indicating that the peptidoglycan structure is similar to that of other gram negative bacteria. Lipoprotein does not appear to be a major component of this peptidoglycan.

Two lipopolysaccharides (LPS) were extracted from PC18 cell walls with phenol/water. One lipopolysaccharide appeared in the aqueous phase (PC18Aq) and one in the phenol phase (PC18Phe). One phenol phase lipopolysaccharide (GA192Phe) and one aqueous phase polysaccharide (GA192Aq) were extracted from str GA192 walls. All three lipopolysaccharides contained mannose, glucose, heptose, 3-deoxy-octulosonic acid, glucosamine and galactosamine in common. The main fatty acids were C₁₁:₀' C₁₃:₀ and 30H C₁₃:₀ . Both PC18 lipopolysaccharides contained a second heptose which was not present in GA192Phe . Sugars unique to each lipopolysaccharide were; PC18Aq, two unidentified amino sugars; GA192Phe, fucose. Each of the phenol soluble lipopolysaccharides could be further separated into chloroform/methanol soluble and insoluble fractions. GA192Aq contained rhamnose, glucose and two unidentified amino sugars.

A glycogen/amylopectin type polysaccharide (presumably the main storage polysaccharide) was isolated from the cytoplasmic fraction of each strain. The results are discussed in terms of known LPS structure and data previously published for S. ruminantium.