Respiratory activities of in vitro grown Mycobacterium lepraemurium

Mycobacterium lepraemurium was cultivated on Ogawa egg-yolk medium and its respiratory activities using several substrates were investigated. Glycerol and succinate were oxidized at a slow rate by the cell-free extracts prepared from in vitro grown Hawaiian and Keishicho strains of M. lepraemurium. None of the other intermediates of the glycolysis cycle as well as of the tricarboxylic acid cycle was oxidized by the whole cell suspensions or cell-free extracts. Likewise, many sulfur compounds such as cystine, mercaptosuccinate, monothioglycerol, thioacetate, etc., were inactive. However, sulfhydryl compounds such as L-cysteine, D-cysteine, DL-cysteine, dithioerythritol, dithiothritol, and DL-penicillamine were actively oxidized. Yeast extract was also readily oxidized by cell suspensions of in vitro grown M. lepraemurium. Tween 80 was very poorly oxidized by whole cell suspensions but the cell-free preparations catalyzed an active oxidation of Tween 80. While bovine serum albumin was oxidized at a slow rate by cell-free extracts, egg albumin was inactive. The thiol-binding agents, p-hydroxymercuribenzoate and N-ethylmaleimide were effective inhibitors of succinate and NADH oxidation, thus indicating the involvement of sulfhydryl compounds in the metabolism of M. lepraemurium.