Radiometric measurement of differential metabolism of fatty acids by Mycobacterium lepraemurium

An assay system has been developed based on automated radiometric quantification of 14CO2 produced through oxidation of (1--14C) fatty acids by mycobacteria. With this system, the Hawaiian strain of M. lepraemurium was studied using the K-36 buffer as a suspending solution for the organisms along with 5.0 muCi of one of the following fatty acids: acetate, butyric, hexanoic, octanoic, decanoic, lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic, and malonic. The 14CO2 production by this organism was greatest with lauric, decanoic, myristic, octanoic, stearic, oleic, linoleic, linolenic, and malonic. The 14CO2 production by this organism was greatest with lauric, decanoic, myristic, octanoic, and stearic acids, in decreasing order. Assimilation studies and radiochromatograms confirmed that most of the oxidized substrates were converted into by-products with no change in those from which no oxidation was found. These data suggest that the radiometric measurement of differential fatty acid metabolism may provide a basis of radiometric identification of M. lepraemurium and assessment of the growth requirements of this organism.