%0 Journal Article %A Walter, Robert P. %A Morris, J. Gareth %A Kell, Douglas B. %T The Roles of Osmotic Stress and Water Activity in the Inhibition of the Growth, Glycolysis and Glucose Phosphotransferase System of Clostridium pasteurianum %D 1987 %J Microbiology, %V 133 %N 2 %P 259-266 %@ 1465-2080 %R https://doi.org/10.1099/00221287-133-2-259 %I Microbiology Society, %X Growth of Clostridium pasteurianum was inhibited in media of high solute content. At equal osmolarities, permeant solutes (glycerol and acetamide) were much less growth-inhibitory than non-permeant solutes (KC1 and xylitol). Glycolysis by washed cell suspensions was inhibited by these solutes in parallel with growth. However, in their inhibition of glucose 6-phosphate dissimilation by permeabilized cells the distinction between permeant and impermeant solutes was significantly less marked. The glucose phosphotransferase system (PTS) of intact cells was much more strongly inhibited by non-permeant than by permeant solutes. It was concluded that the predominant inhibitory effects on this organism of media of high solute content are due not to the low water activity of such media per se, but to the creation of an osmotic pressure across the bacterial cytoplasmic membrane, which acts to inhibit the glucose PTS by which the organism effects glucose uptake. Parallel measurements of the effects of xylitol on both glycolysis and the activity of the glucose PTS suggested that despite this correlation between the osmotic inhibition of growth, glycolysis and the PTS, the flux-control coefficient of the PTS on glycolysis did not exceed 0.2 under the conditions used. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-133-2-259