Growth of 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 , 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.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error