The Roles of Osmotic Stress and Water Activity in the Inhibition of the Growth, Glycolysis and Glucose Phosphotransferase System of Clostridium pasteurianum

Abstract

Growth of Clostridium pasteurianurn 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.

Control of metabolite efflux in microbial cell factories: current advances and future prospects

“…Increasing the rate of such steps will by definition increase fluxes. Both influx and efflux transporters tend to have this property (for an early example, see [77]). …”

“…Osmotic stress can modulate the activity of membrane transporters (e.g. [77]), and this is the basis for the mechanosensitive efflux pumps e.g. for glutamate (see above).…”

Synergistic effect of sonication and high osmotic pressure enhances membrane damage and viability loss of Salmonella in orange juice

“…High osmotic pressure also affects bacterial survival (Bayer, 1967;Del Valle, 1983;Levandowsky, 1981;Mille, Beney, & Gervais, 2005;Poirier, Marechal, Evrard, & Gervais, 1998;Walter, Morris, & Kell, 1987). Abrupt changes of osmotic pressure in the medium are well known to affect bacterial survival, whether through osmotic shock (immediate effect) or long exposure to high osmotic pressure (Bayer, 1967;Mille, Beney, & Gervais, 2002;Poirier et al, 1998).…”

“…Abrupt changes of osmotic pressure in the medium are well known to affect bacterial survival, whether through osmotic shock (immediate effect) or long exposure to high osmotic pressure (Bayer, 1967;Mille, Beney, & Gervais, 2002;Poirier et al, 1998). High osmotic pressure causes metabolic perturbation, presumably by inhibiting the glucose phosphotransferase system through which microorganisms take up glucose (Walter et al, 1987).…”

Influence of Osmotic Stress on Fermentative Production of Succinic Acid by Actinobacillus succinogenes

“…Increased osmotic stress of the culture broth results in simultaneous cell shrinkage, water flux out of the cytoplasm, and reduced turgor pressure in most of the industrial strains. This results in the inhibition of a variety of physiological processes [7][8][9][10][11]. A variety of stress-adaptation mechanisms are acquired to protect these cells from such osmotic stress.…”