Abstract
Summary
1) Nitrate reductase is inactive in non-proliferating dihydro streptomycin resistant and dependent V. comma cells and their extracts, as compared to the sensitive parent strain. Nitratase activity was found in resting cells of the sensitive strain but not in resistant and dependent mutants. Dihydro streptomycin did not inhibit but rather stimulated the nitratase activity of the sensitive strain. 2) Oxygen uptake in the presence of any of the following substrates was strongly inhibited in resistant and dependent mutant as compared to the sensitive strain: glucose, pyruvate, succinate, malate, oxaloacetate, α-ketoglutarate and fumarate. 3) Striking differences in rate of reduction of neo-tetrazolium were also observed in the presence of various substrates when the 3 strains were compared. The same pattern of high activity in the sensitive strain and practically, no activity in the dependent and resistant strains was always prevalent. Here too, the presence of antibiotic resulted in stimulation of activity of the sensitive strain in the presence of most substrates tested.
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