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.

Cell envelope of Neisseria gonorrhoeae CS7: peptidoglycan protein complex

“…80 and 20%, respectively). In cells grown at pH 6.0 glucose is catabolized 50% by the Entner-Douderoff pathway and 50% by the pentose-phosphate pathway (17,18). Also, unlike the cells grown at pH 7.2, the cells grown at pH 6.0 had an active tricarboxylic acid cycle.…”

“…We have reported previously that the pH of the growth medium markedly affects the pathways by which glucose is dissimilated (17,18) and the composition of the cell envelope (9,10). In this communication we describe a major modification of the protein content of the peptidoglycan complex during growth at various pH values.…”

Regulation and differential expression of gdhA encoding NADP‐specific glutamate dehydrogenase in Neisseria meningitidis clinical isolates

“…At neutral pH values, the catabolism of glucose results in the accumulation of acetate, which is not further catabolized until glucose is depleted or growth becomes limiting. Indeed, growth on glucose markedly reduces the levels of TCA cycle enzymes in gonococci (Hebeler and Morse, 1976; Morse and Hebeler, 1978).…”

The standard model prediction of the muon anomalous magnetic moment

“…Among the possible causes of this discrepancy, one may wonder about inconsistencies in the e + e − data, in the τ data, or in the isospin-breaking corrections applied to the τ spectral functions. Given the good consistency of the ALEPH and CLEO data sets, and the confirmation by KLOE of the trend exhibited by other e + e − data, further careful investigations of the isospin-violating effects are clearly warranted -see the interesting studies in [92,93,103,[118][119][120], in particular the discussion of the possible difference between the masses and the widths of neutral and charged ρ-mesons. Until we reach a better understanding of this problem, it is probably safer to discard information from τ decays for the evaluation of a HLO µ [93].…”