| Autor: |
Warr, S. R. C., Reed, R. H., Stewart, W. D. P. |
| Předmět: |
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| Zdroj: |
Plant, Cell & Environment; Mar1988, Vol. 11 Issue 2, p137-142, 6p |
| Abstrakt: |
The solutes accumulated by cyanobacteria in response to hyper-osmotic stress include Na+, K+, sucrose, trehalose, glucosyl-glycerol, glycine betaine and glutamate betaine. The compatibility of several of these solutes with glutamine synthetase activity has been examined using cell-free extracts from a range of freshwater, marine and halotolerant cyanobacteria. All of the solutes tested were compatible with (i.e. non-inhibitory to) enzymic activity at physiological concentrations and the results demonstrate a rank order of compatibility which correlates with the concentrations at which the organic solutes occur in cyanobacteria, i.e. glycine betaine > polyol-derivatives > disaccharides and with the upper salinity limit for growth. The protection against inhibition by NaCl (halo-protection) afforded by these solutes to enzymic activity was also examined. Only glycine betaine was found to exert a significant halo-protective effect and this may be explained by differences in the mechanism of compatible solute function between small charged molecules and sugars/polyols. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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