Changes in turgor pressure in response to increases in external NaCl concentration in the gas-vacuolate cyanobacteriumMicrocystissp.

✍ Scribed by R. H. Reed; A. E. Walsby

• Book ID: 104762954
• Publisher: Springer
• Year: 1985
• Tongue: English
• Weight: 806 KB
• Volume: 143
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00411252

✦ Synopsis

Changes in cell turgot pressure have been followed in cells of Microcystis sp. transferred to culture medium containing, added NaC1 at osmolalities of 3 0 -1,500 mosmolkg -1 ( -74-3,680 kPa). Upon upshock turgor decreased, due to osmotically-induced water loss from the cell. However, partial recovery of turgot was then observed in illuminated cells, with maximum turgor regain in media containing 3 0 -500 mosmol kg-1 NaC1. The lightdependent recovery of turgor pressure was completed within 60 rain, with no evidence of further changes in cell turgor up to 24 h. This is the first direct evidence that turgor regulation may occur in a prokaryotic organism. Short-term increases in cell K + content were also observed upon upshock in NaC1, indicating that turgot regain may involve a turgotsensitive K + uptake system. Estimation of internal K + concentration in cells transferred to 250 mosmol kg-1 NaC1 showed that changes in cell K + may account for at least half of the observed turgot regain up to 60 min.