Osmoregulator function

Surprisingly, very little physiological work has been done to understand the nature and processes of plant recovery from extreme drought stress, especially in relation to plant production (Chapter 7). In order for the plant to recover properly from severe water stress, its various meristems must survive. The association between severe plant stress and the factors that affect meristem survival and function upon rehydration are unclear though osmoregulation may have a possible protective role and as a potential source of carbon for recovery. Active plant apices generally excel in osmoregulation and do not lose much water upon plant dehydration (Barlow, Munns Brady, 1980). 

DMSP (21) is produced by many marine micro- and macroalgae and is especially prominent in dinoflagellates and haptophytes. The nontoxic DMSP (21) fulfills multiple cellular functions including cryoprotection, the involvement as osmolyte in osmoregulation and as a methyl donor in transmethylation reactions [18]. 

Urea has been of interest to the biological oceanographer because of its role as an excretion product of protein metabolism, its function in osmoregulation, and its reported use as a nitrogen source for phytoplankton growth. 

N-acetylaspartate is among the most abundant amino acids in the brain, although its precise function remains elusive. Putative roles have included osmoregulation and... 

Chalker-Scott, L., Do anthocyanins function as osmoregulators in leaf tissues, in Anthocyanins in Leaves. Advances in Botanical Research, vol. 37, Gould, K.S. and Lee, D.W., Eds., Academic Press, Amsterdam, 2002, 103. 

Tokishita, S. Kojima, A. Mizuno, T. Transmembrane signal transduction and osmoregulation in Escherichia coli functional importance of the transmembrane regions of membrane-located protein kinase, EnvZ. J. Biochem., Ill, 707-713 (1992)... 

The kidney of most fish is primarily involved in hematopoiesis and osmoregulation. Fresh-water fish are hypertonic relative to the water. The continual osmotic uptake of water is balanced by production of as large amounts as 2-4 ml/kg/h of dilute urine. Salt-water fish, on the other hand, are hypotonic relative to their environment, resulting in body water loss. In response, marine species produce much smaller volumes of urine. Large differences exist among different fish species in regard to nephron structure to facilitate these functional responses. These features may influence the renal contribution to drug disposition apprecia-... 

Delauney, A.J. Verma, D.P.S. (19906). A soybean gene encoding A pyrroline-S-carboxylate reductase was isolated by functional complementation in Escherichia coli and found to be osmoregulated. Molecular and General Genetics 221, 299-305. 

Clark, M.E. (1985). The osmotic role of amino acids discovery and function. In Transport Processes, Iono- and Osmoregulation, pp. 412—423, ed. R. Gilles and M. Gilles-Baillien. Berlin Springer-Verlag. 

Skadhauge, E., Warui, C.N., Kamau, J.M.Z. Maloiy, G.M.D. (1984). Function of the lower intestine and osmoregulation in the ostrich, Struthio camelus preliminary anatomical and physiological considerations. Quarterly Journal of Experimental Physiology, 69, 809-18. 

Lynn, J. K., Murty, C. N., and Sidransky, H., Osmoregulation of ribosomal function in mouse liver, Biochim. Biophys. Acta, 299, 444, 1973. 

How trematodes re-establish osmotic equilibrium is not known. They have a well-developed protonephridial system that may function in osmoregulation. However, there is no evidence that the protonephridial system responds to ionic or osmotic stress... 

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