Cells of Porphyra perforata, a red marine alga, accumulate K in the absence of concomitant Na or Li extrusion while immersed in Li- or Mg-sea waters lacking Na. This suggests that the coupling observed between K and Na transport is facultative. No evidence is obtained for net extrusion of Li. Na efflux, with the concentration gradient, is facilitated by K and is proportional to the cellular Na ...

PURPOSE In a previous study, an increase in Na,K-ATPase alpha 2 expression was detected in the epithelium of porcine lenses exposed to amphotericin B, an ionophore that also increases lens sodium and stimulates active sodium transport. The purpose of the present study was to determine whether an increase of Na,K-ATPase alpha 2 synthesis is a response to an episode of rapid Na-K transport or whe...

With a view to test how the branchial and intestinal tissues of fish, the two sites of metal acquisition, utilize the water-borne ferric [Fe(III)] iron and whether the accumulation of this form of iron influences cellular Na/K gradient in these tissues, the gills and intestines of climbing perch adapted to freshwater (FW) and acclimated to dilute seawater (20 ppt; SW) were analyzed for ouabain-...

Previous publications have described a "volume controlling mechanism" in duck erythrocytes that returns both enlarged and shrunken cells to their original isotonic volume. Enlarged cells return to their original size by readjusting their K content. To study the specificity of this aspect of the mechanism for K, we prepared enlarged cells with various Na and K contents. Only cells containing a h...

Hemisodium is a novel Na ionophore that belongs to the class of compounds called cryptands. These compounds possess an electron-rich cavity for binding of cations and are conformationally organized during synthesis to favor the selective binding of one cation over another. In media containing 145 mM NaCl and 5 mM KCl, hemisodium (10(-5) M) increased erythrocyte Na content from 23 to 345 mmol/kg...

Samples of external oblique muscles were surgically removed from 45 renal stone patients and analyzed for their K, Na and Mg content. The muscle samples were also measured for membrane Na, K-ATPase activity from the assay of its K+-dependent 3-0-methyl fluorescein phosphatase (K+-dependent 3-0-MFPase) activity. The results showed that the mean muscle contents +/- SEM of K, Na and Mg were 65.2 +...

crops growing in salt-affected soils may suffer from physiological drought stress, ion toxicity, and mineral deficiency. a pot study was conducted in 2004-2005 in the aghala area (northern iran) to study the effect of different salinity levels, i.e. ece= 3 (control), 8, 12 and 16 ds m-1 on wheat grain, yield components and leaf ion uptake of four iranian wheat genotypes, i.e. kouhdasht, atrak, ...

This study was carried out in the Middle Governorate of Gaza Strip, Palestine. The coastal aquifer is the main source of water for domestic, agricultural, and industrial purposes in the study area. During the last three decades the aquifer has deteriorated to a high degree in the quality and quantity due to the over-pumping and the encroachment of seawater.  Hydrogeochemical analysis for ground...