Abstract
Dihydrostreptomycin not only depressed the bacterial accumulation of α-ketoglutarate from a variety of carbonaceous substances including glucose, acetate, pyruvate, lactate and C4-dicarboxylic acids such as succinate, fumarate and malate, but also stimulated the bacterial oxidation of α-keto-glutarate under suitable conditions. The dihydrostreptomycin-resistive strains were found to induce α-ketoglutaric acid-fermentation, and an explanation was put forward for the mechanism of development of drug-resistance. Chloramphenicol was observed to inhibit the α-ketoglutarate-synthe-sizing system in the bacteria without causing any inhibition of the oxidative removal of a variety of carbonaceous substances. It was concluded that the bacteria possessed both oxidation oz respiration system; one was sensitive to the drug and the other non-sensitive. The mode of action of streptomycin or chloramphenicol upon the formation of an adaptive enzyme (protein synthesis) was discussed here, based on the results of present investigations. Tetracycline and the related compounds were ascertained to greatly inhibit the consumption of substrates by the bacteria.
