PERTURBATION OF ANION BALANCE DURING INHIBITION OF GROWTH OF ESCHERICHIA-COLI BY WEAK ACIDS

During inhibition of cell growth by weak acids, there is substantial a ccumulation of the weak acid anions in the cytoplasm. This study was u ndertaken to determine the impact of anion accumulation on cellular po ols. At pH 6, growth in the presence of 8 mM acetate led to an interna l pool of greater than 240 mM acetate anion and resulted in reduced le vels of glutamate in the cell, but there were no significant changes i n K+ and Na+ levels. At low osmolarity, the change in the glutamate po ol compensated for only a small fraction of the accumulated acetate an ion. However, at high osmolarity, glutamate compensated for over half of the accumulated acetate. Recovery of the normal cytoplasmic pH afte r the removal of acetate was dependent on the synthesis of glutamate.