Growth Inhibition of Tubercle Bacilli by Analogues of Biotin

Abstract

Woods' report in 1940 on the mode of action of sulfanilamide initiated a new era in the study of chemotherapeutic agents. In the past decade hundreds of new drugs patterned after specific metabolites have been synthesized. Among these are a number of biotin analogues whose inhibitory activity for a variety of organisms has been described. In most instances activity of the compound has been limited to nonpathogenic organsms requiring an exogenous source of the vitamin, but biotin analogues have shown little activity against organisms that synthesize their own biotin. The present paper reports the inhibitory activity of several biotin antagonists on a virulent strain of Mycobacterium tuberculosis. Our interest in these compounds lies not only in their potential chemotherapeutic value but also in their use in studies of biotin metabolism in the tubercle bacillus. MATERIALS AND METHODS A. In vitro studies. The virulent H37Rv strain of Mycobacterium tuberculovsi was used in this study. Test cultures were made in Proskauer-Beck synthetic medium in 4-oz prescription bottles containing the analogue up to a final volume of 20 ml. One loopful of organisms from a young culture (2 to 4 weeks old) was used as the inoculum and was floated on the surface of the medium. The micro

The Roles of Biotin and Carbon Dioxide in the Cultivation of Mycobacterium Tuberculosis,

“…Having shown that incubation under increased C02 tension substitutes for a requirement for biotin, it seemed of interest to investigate whether increased C02 tension actually eliminates the need for biotin as a necessary growth factor or only decreases the amount of biotin required for C02 assimilation. For this study the biotin analogue 4-(imidazolidone-2) caproic acid" was used because it is known to inhibit growth of tubercle bacilli by antagonizing endogenous biotin (Pope, 1952). The effect of increased C02 tension and of biotin on this inhibition was studied.…”