FIXATION OF C14O2 INTO NUCLEIC ACID CONSTITUENTS BY BRUCELLA ABORTUS

In a variety of animal tissues, the synthesis of nucleic acid constituents can take place from elementary precursors; among these, carbon dioxide and glycine have been demonstrated to be incorporated into purines of many higher animals as well as yeast (Buchanan, 1951). Relatively little direct evidence is available on the precursors of nucleic acid constituents in bacteria. Sutton et al. (1951) reported the incorporation of glycine into purines of Aerobacter aerogenes, and recently Bolton et al. (1952) have shown that carbon dioxide is a precursor of the nucleic acid purines and pyrimidines of Escherichia coli. The synthesis of nucleic acid constituents in Brucella abortus is of particular interest because many strains of the organism require added carbon dioxide for growth, and glycine appears to be a major product of CO2 fixation in such strains (AIarr and Wilson, 1951). However, neither glycine nor any compound or complex mixture yet tested will replace added CO2 for growth of B. abortus. Wte have investigated the fixation of C'402 into nucleic acid constituents by B. abortus to examine further the biochemical basis of the need for CO2 by members of this species.