Curtis B. Thorne, Carmen G. Gómez, Riley D. Housewright
1952 Journal of Bacteriology  
In a previous paper (Housewright and Thorne, 1950) it was shown that Bacillus anthracis is able to synthesize large quantities of glutamic acid by transamination. However, the glutamic acid synthesized by transamination was entirely the L-isomer, and under the conditions of those experiments none was bound as glutamyl polypeptide. The present paper deals with the synthesis of glutamyl polypeptide by growing cultures and the effect of CO2 or bicarbonate on that synthesis. Although the
more » ... ough the stimulating effect of CO2 or bicarbonate on capsule formation by B. anthracis has been known forseveral years (IvAnovics, 1937; Sterne, 1937) , most of the results reported in the literature are based only on observations by use of the microscope. Little or no quantitative work on the effect of CO2 on glutamyl polypeptide (capsule) production has appeared. In the work reported here, the glutamyl polypeptide was determined quantitatively. EXPERIMENTAL METHODS Cultures. The cultures of B. anthracis used included three highly virulent strains, 994, M-36, and 99, and two avirulent strains, M and HM. Stock spore suspensions of all strains except HM were used. This strain, which does not form spores, was maintained on nutrient agar. Analytical methods. Total glutamic acid was determined by the paper chromatographic method described in the first paper of this series (Housewright and Thorne, 1950) . L-Glutamic acid was determined by a modification of the decarboxylase method of Umbreit and Gunsalus (1945). D-Glutamic acid was estimated by subtracting the amount of the L-isomer from the total amount of glutamic acid present. Kjeldahl nitrogen was determined by a modification of the method of Johnson (1941). Media. The synthetic medium was a modification of that described by Brewer et al. (1946) . Tyrosine and glutamine were omitted, and 0.1 per cent (NH4)2SO4 and 2.5 per cent agar were added. When NaHCO3 was used, it was sterilized by filtration and added after the medium had cooled to 45 to 50 C. The CCY medium was the hydrolyzed casein-yeast extract medium of Gladstone and Fildes (1940) . The other natural medium contained 0.8 per cent nutrient broth (Difco), 0.3 per cent yeast extract (Difco), 0.5 per cent glucose, and 2.5 per cent agar. Method for studying factors affecting peptide production. The following method 363 on May 7, 2020 by guest
doi:10.1128/jb.63.3.363-368.1952 fatcat:jkxcv4ftevglxfntooqiuhyhlq