Hyperosmotic stress

Kanesaki, Y., I. Suzuki, S. I. Allakverdiev, K. Mikami, and N. Murata (2002). Salt stress and hyperosmotic stress regulate the expression of different sets of genes in Synechocystis sp PCC6803. Biochem Biophys... 

A beneficial function of urea preventing covalent damage to DNA during hyperosmotic stress... 

Although most of the focus on solute effects on macromolecular systems has involved proteins, there is evidence that some of the patterns of solute accumulation reflect the dangers that high salt concentrations pose for the covalent structure of DNA. Using cultured mammalian kidney cells Kiiltz and Chakravarty (2001) showed that hyperosmotic stress could cause double strand breaks (dsb) in DNA. Hyperosmolality due to elevated [NaCl] in the culture medium caused the most dsb. Potassium chloride and mannitol led to less damage and, interestingly, no damage to DNA was found in cells exposed to elevated levels of urea. 

The second event in this initial phase of the response of E. coli to hyperosmotic stress is the synthesis of glutamate, which replaces Cr as a counterion to K+ (figure 6.15). Increased synthesis of glutamate occurs quickly, usually within a minute of exposure to hyperosmotic stress, but it cannot occur until the initial rise in concentration of intracellular K+ has taken place. 

When external salinity is decreased from 0.5 M to 0.1 M, there is a rapid fall in glycerol content within several minutes. Starch content appears to be restored almost immediately to the value observed prior to hyperosmotic stress (figure 6.16, lower panel). These data show that the ability to rejoin an osmolyte molecule to an osmotically inert polymer enables the cell to decrease its osmotic content very rapidly,... 

It is instructive to compare the mechanisms used by mammalian kidney cells to adapt to hyperosmotic stress with the osmoregulatory mechanisms used by soil bacteria exposed to high ambient osmolality. The unity in diversity so commonly found in comparative biochemistry is well illustrated by this comparison. Cells of the inner medulla of the mammalian kidney, like hyperosmotically stressed bacteria cells, (i) accumulate compatible organic osmolytes when... 

The synthesis of several proteins playing key roles in osmotic regulation is increased following exposure to hyperosmotic stress (reviewed in Burg et al., 1997). Transporters for glycine betaine, taurine, and inositol all increase in abundance over a period of several hours. This up-regulation of transporter activity... 

Cohen, D., J. Wasserman, and S. Gullans (1991). Immediate early gene and HSP70 expression in hyperosmotic stress in MDCK cells. Am. J. Physiol. (Cell Physiol.) 261 C594-601. 

Ferarris, J.D., C.K. Williams, K.-Y. Jung, J.J. Bedford, M.B. Burg, and A. Garcia-Perez (1996). ORE, a eukaryotic minimal essential osmotic response element the aldose reductase gene in hyperosmotic stress. J. Biol. Chem. 271 18318-18321. 

The alga Phaerodactilum tricornutum was found to respond to hyperosmotic stress by a marked elongation of PolyP and a decrease in its total amount, while exposure to hypoosmotic stress resulted in a higher content of shorter PolyPs and an increased total PolyPs content (Leitao et al., 1995). It is probable that, such variations might allow the adjustment of the intracellular osmotic pressure to an extracellular one. 

Drbak, B.K., and Watkins, P.A., 2000, Inositol(l,4,5)trisphosphate production in plant cells an early response to salinity and hyperosmotic stress. FEBS Lett. 481 240-244. 

Monks, D.E., Aghoram, K., Courtney, P.D., DeWald, D.B., and Dewey, R.E., 2001, Hyperosmotic stress induces the rapid phosphorylation of a soybean phosphatidylinositol transfer protein homolog through activation of the protein kinases SPK1 and SPK2. Plant Cell 13 1205-1219. 

Pical, C., Westergren, T., Dove, S.K., Larsson, C., and Sommarin, M., 1999, Salinity and hyperosmotic stress induce rapid increases in phosphatidylinositol 4,5-bisphosphate, diacylglycerol pyrophosphate, and phosphatidylcholine in Arabidopsis thaliana cells. J. Biol. Chem. 274 38232-38240. 

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