D-Cycloserine-induced alterations in the transport of D-alanine and glycine in Bacillus subtilis 168.

d-Alanine, l-alanine, and glycine transport was investigated in Bacillus subtilis 168 cells that were phenotypically resistant to d-cycloserine. These cells showed enhanced rates of uptake as compared with that observed in sensitive cells. The usual enhancement in d-alanine and glycine transport resulting from treatment of the cells with d-cycloserine could be prevented by the addition of rifampin. Kinetic analyses of the initial rate of glycine transport indicated an increase in the V(max) for transport in resistant cells, with no alteration in the K(m) for glycine. Investigations of the net transport of glycine revealed that resistant cells maintained a higher gradient of glycine than did sensitive cells. Kinetic analyses of the net transport of glycine suggested that a new system for the accumulation of glycine was present in d-cycloserine-resistant cells.