ELECTRON-TRANSPORT COMPONENTS OF STREPTOMYCIN-DEPENDENT ESCHERICHIA COLI.

Bragg, P. D. (University of British Columbia, Vancouver, B. C, Canada) and W. J. Polglase. Electron-transport components of streptomycin-dependent Escherichia coli. J. Bacteriol. 86:544-547. 1963.-When a streptomycin-dependent strain of Escherichia coli was grown in antibiotic-free medium, the resulting streptomycin-depleted cells were found to contain relatively large amounts of vitamin K(2). Cytochromes a(1) and a(2) were absent from depleted cells, and these cells metabolized glucose with the accumulation of lactic acid. Depleted cells were normal in their content of coenzyme Q(8), total flavine, and cytochrome b. Growth of depleted cells on medium containing dihydrostreptomycin restored their ability to metabolize lactic acid concomitantly with a decrease in vitamin K(2) to a normal level, and with the formation of cytochromes a(1) and a(2). It is concluded that streptomycin (or dihydrostreptomycin) is required by dependent E. coli for maintenance of the integrity of the electron-transport system.