%0 Journal Article %A Whatmore, Adrian M. %A Reed, Robert H. %T Determination of turgor pressure in Bacillus subtilis: a possible role for K+ in turgor regulation %D 1990 %J Microbiology, %V 136 %N 12 %P 2521-2526 %@ 1465-2080 %R https://doi.org/10.1099/00221287-136-12-2521 %I Microbiology Society, %X The effects of hypersaline treatment (osmotic upshock) on cell water relations were examined in the Gram-positive bacterium Bacillus subtilis using particle size analysis. Application of the Boyle-van't Hoflf relationship (cell volume versus reciprocal of external osmolality) permitted direct determination of turgor pressure, which was approximately 0·75 osmol kg−1 (1·9 MPa) in exponentially growing bacteria in a defined medium. The abolition of turgor pressure immediately after upshock and the subsequent recovery of turgor were investigated. Recovery of turgor was K+ dependent. Calculation of turgor by an alternative method involving spectrophotometric analysis of shrinkage gave somewhat lower estimates of turgor pressure. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-136-12-2521