Ht. Chang et al., KINETICS OF SUBSTRATE OXIDATION BY WHOLE CELLS AND CELL-MEMBRANES OF HELICOBACTER-PYLORI, FEMS microbiology letters, 129(1), 1995, pp. 33-38
Oxygen uptake by Helicobacter pylori cells and membranes was determine
d. Cells from stirred broth cultures or agar plates, suspended in buff
er, possessed a variable and apparently endogenous respiration which c
ould be sustained for several hours. In contrast, oxygen consumption b
y cells from statically incubated broth cultures, in the absence of ad
ded substrate, was transient or undetectable. These latter cells, howe
ver, oxidised ethanol, fumarate, glucose, D-lactate, pyruvate and succ
inate, though glucose-oxidising ability declined rapidly. The K(m)s fo
r D-lactate, pyruvate and succinate metabolism were low (less than or
equal to 20 mu M) and oxygen uptake was approximately 1.5, 2 and 2 mol
per mol substrate respectively, indicating metabolism beyond acetate
plus CO2 and implying the presence of tricarboxylic acid cycle activit
y. Cell membranes oxidised fumarate, D-lactate, NADH, NADPH and succin
ate. NADPH oxidation was six times more rapid than that of NADH. Rates
of oxygen uptake by cells suspended in buffer with metabolisable subs
trate were < 20% of those for cells suspended in a brain heart infusio
n medium. Uninoculated medium consumed significant quantities of oxyge
n.