Article Abstract:
The protein profile of Bacteroides ovatus was analyzed to determine the enzyme patterns involved in the breakdown of guar gum. Growth on guar gum induced 12 soluble proteins and 20 membrane proteins. Among the proteins detected, galactomannanase I and II, membrane polypeptide o, and soluble proteins d and g were induced by both guar gum and glucose. Analysis of transposon-induced mutants revealed unchanged expression in the known degradative enzymes, while the derivative suppressor mutants showed some wild-type induced proteins as not limiting for growth on guar gum. Results indicate that regulation of guar gum utilization is complex.
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Article Abstract:
The effects of glucose and nitrogen limitation on cells of Bacteroides ruminicola B(sub 1)4 were studied. Under nitrogen-limiting conditions, glucose concentrations of 10 to 50 millimolar were toxic to cells. Toxicity was not dueto end product inhibition or nitrogen limitation. A glucose- resistant mutant transported glucose at a much lower rate and stored less polysaccharide than the wild type. These results indicate that B. ruminicola B(sub 1)4 is unable toregulate the transport and utilization of glucose under nitrogen-limiting conditions.
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Article Abstract:
The major sources of carbohydrate for Bacteroides ovatus in the intestinal tract of germfree mice were determined by analysis of the bacterial disaccharidase expression patterns. The enzymes with the highest activities were beta- and alpha-glucosidase and alpha-galactosidase. The patterns observed were most consistent with low-level utilization of many different substrates rather than a single major carbohydrate source. Hence, the absence of even a minor substrate could have deleterious effects in vivo.
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