Action of metal chelates on growth initiation of Bacillus subtilis

Mayer, Gerald D. (University of Southwestern Louisiana, Lafayette) and R. W. Traxler. Action of metal chelates on growth initiation of Bacillus subtilis. J. Bacteriol. 83:1281-1286. 1962.-Certain compounds which have a potential as metal chelates are stimulatory for Bacillus subtilis at low concentrations. If the concentration of these compounds is increased beyond the optimum for prompt growth initiation, they become inhibitory. It is demonstrated that this organism requires a critical concentration of manganese for growth initiation. If the manganese concentration is increased there is a corresponding increase in the lag time and, therefore, in the growth time of the culture. At a manganese concentration of 10 mug per ml growth is completely inhibited. The manganese inhibition can be reversed by the addition of a chelate. Dialysis of cells with chelate presumably removes a metal ion(s) essential for the initiation of growth. Supplementing kojic acid-dialyzed cells with additional manganese reverses this inhibitory effect to some extent, indicating that the removal of manganese by the chelate dialysis is partially responsible for the increased time for growth initiation.