Aquaporins facilitate the diffusion of water across cell membranes. We previously showed that acid pH or low Ca 2 increase the water permeability of bovine AQP0 expressed in Xenopus oocytes. We now show that external histidines in loops A and C mediate the pH dependence. Furthermore, the position of histidines in different members of the aquaporin family can “tune” the pH sensitivity toward alk...

natural ecosystems provide many goods and services for human beings via their multiple functionalities. one of these important functions is the role of natural ecosystems in regulation of hydrologic cycle and increasing the infiltarion and retention of water in soil context and preventing from water runoff which may cause in unfavorable consequences like soil erosion and flooding. quantificatio...

Regulation of urea concentration in the renal medullary interstitium is important for maintenance of hypertonicity and therefore the osmotic driving force for water reabsorption. Studies in Sprague-Dawley rats showed that restriction of water intake for 3 days results in upregulation of urea transporter (UT) mRNA in the inner stripe of outer medulla of the kidney (2.9-kb UT2) but not in the inn...

serotonin (5-ht), a mono-aminergic neurotransmitter is biochemically derived from tryptophan and is mainly found in gastrointestinal tract, platelets and central nervous system of animals. serotonin (5-ht) in coordination with hypothalamus plays an important role in the cns control of appetite, eating behavior, and energy balance and body weight. it has a special role in control of carbohydrate...

The long-term regulation of arterial pressure requires the maintenance of a balance between sodium and water intake and sodium and water excretion. Normal salt and water balance leads to stable body fluid volumes and the maintenance of normal renal function is critical to establishing extracellular fluid volume homeostasis. This review focuses on the role of the kidney in the long-term control ...

Water-level fluctuations (WLF) affect the ecological processes and patterns of lakes in several ways. Aquatic habitats and feeding or breeding grounds are gained or lost, as light, climate and wave impacts change to mention only a few phenomena. While the phenomenon of WLF has been studied in many rivers (better known as flood pulse, Junk & Wantzen, 2004) and environmental flows (Bunn et al., 2...