EFFECT OF THE ISOMERIC CONFIGURATION OF THE SOURCE OF NITROGEN ON CHANGES IN POPULATION AND METABOLISM IN CULTURES OF BRUCELLA

Abstract

In initially smooth cultures of Brucella, alanine accumulation and population changes differ greatly depending on whether D or L-asparagine is employed as the sole source of N in the synthetic medium employed. Thus, in contrast to results obtained previously with D or DL-asparagine, smooth cultures of B. abortus, strain 6232, showed neither establishment of non-smooth types when grown in L-asparagine nor significant amts. of alanine in filtrates from such cultures incubated for prolonged periods. The establishment of a non-smooth (mucoid) mutant differing from the rough mutant observed after growth in D or DL-asparagine was noted in initially smooth cultures of B. suis grown in L-asparagine. In the latter medium no alanine was detectable, but an amino acid that appears to be identical with valine accumulated at the time of population change. Preliminary tests indicate that, for this strain of B. suis, valine accumulating during growth in L-asparagine may act in a manner similar to the action of alanine accumulating during growth in D-asparagine. Data illustrating these differential effects of isomers of amino acids upon growth, population changes, and metabolite production are presented.