NUTRITIONAL FACTORS INFLUENCING THE POLYSACCHARIDE PRODUCTION OF BRUCELLA SUIS

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Abstract
Growth of B. suis at 37 C in complex media containing varying combinations of 0.5 - 4.0% de-acidified casein partial hydrolyzate, 0.25 - 1.0% yeast autolysate and 1.0 - 5.0% glucose yielded cells with altered cellular polysaccharide content, ranging from 1.5 - 20% of dry cell weight. Maximum polysaccharide synthesis occurred at the termination of the log phase of growth at pH 7.5 with glucose as the C source. Polysaccharide synthesis was inhibited significantly by addition to the medium of increasing concentrations of the casein hydrolyzate or amino acid supplements containing DL-valine; addition of polypeptides exhibited no effect. Polysaccharide synthesis by resting cell suspensions in a solution of phosphate buffer (0.1 [image], pH 6.0 or pH 7.0) and glucose (2%) also was inhibited by the combination of DL-valine and L-lysine. Data do not permit specific conclusions as to the mode of action of the amino acids during inhibition of polysaccharide synthesis.