INHIBITION OF MICROBIAL GROWTH AND SEPARATION BY D-SERINE, VANCOMYCIN, AND MITOMYCIN C.

Durham, Norman N. (Oklahoma State University, Stillwater). Inhibition of microbial growth and separation by d-serine, vancomycin, and mitomycin C. J. Bacteriol. 86:380-386. 1963.-A study was made of the growth and separation inhibition of Pseudomonas fluorescens by vancomycin and mitomycin C and of a Flavobacterium sp. sensitive to mitomycin C and d-serine. Aberrant morphological forms (primarily "boat-shaped" cells and "chain-like" filaments) were observed during growth of the sensitive organism in the presence of the inhibitors. Reversal studies indicated that Mg(++), and to a lesser extent Mn(++), partially reversed vancomycin and mitomycin C growth inhibition during the early stages of growth but did not influence d-serine inhibition. Selected metabolites also showed a tendency to partially reverse mitomycin C and vancomycin inhibition of growth during the initial growth phase, and the differences in reversal trends suggested that d-serine, vancomycin, and mitomycin C produce metabolic lesions at different sites in the cell with respect to growth. Cultivation of the sensitive organism in low concentrations of the inhibitors resulted in a structurally fragile population, indicating formation of a defective cell structure. Mg(++) partially reversed the vancomycin inhibition of separation in these organisms. None of the other metals or metabolites, either singly or in varied combinations, was able to reverse inhibition of separation by the various inhibitors.