Effect of pH on the growth and glucose metabolism of Neisseria gonorrhoeae

Abstract

This study examined the effect of pH on the metabolism of glucose by Neisseria gonorrhoeae. Radiorespirometric studies revealed that cells growing at pH 7.2 or 8.0 metabolized glucose primarily (ca. 80%) via the Entner-Doudoroff pathway. The remainder of the glucose was metabolized via the pentose phosphate pathway (ca. 20%). The tricarboxylic acid cycle was not active during glucose catabolism at either pH 7.2 or 8.0, and acetate accumulated in the medium. Cells growing at pH 6.0 had markedly increased pentose phosphate pathway activity (ca. 50%) and a functioning tricarboxylic acid cycle. The alteration in pathways was not due to differences in growth rate, but to the pH of the medium. Chemical fractionation of labeled cells and total hexose analyses revealed that growth pH markedly affected the composition of the gonococcus.