Here we found that the enantioselectivity of G-quadruplex DNA-based Diels-Alder reaction can be switched by just changing Na(+) to K(+), which is ascribed to the structural transformation of the G-quadruplex from antiparallel to hybrid-type. By tuning the ratio of Na(+)/K(+), the enantioselectivity of the Diels-Alder reaction could be switchable and shows much more sensitive to K(+) than to Na(+).

The electrophysiology of the renal Na-K ATPase was studied in isolated perfused amphibian proximal tubules during alterations in bath (serosal) potassium. Intracellular and extracellular ionic activity measurements permitted continuous evaluation of the Nernst potentials for Na+, K+, and Cl- across the basolateral membrane. The cell membrane and transepithelial potential differences and resista...

introduction abiotic stresses cause 71% reduction in crop yield around the world, from which 20% is related to salinity stress. the importance of sugarcane increases every day due to greater demand for sugar. since sugarcane has mainly grown in arid and semi-arid regions, salinity is one of the main problems for this crop due to higher evaporation in these areas. salicylic acid (sa) is classifi...

Genetic and physiological data establish that Arabidopsis AtHKT1 facilitates Na(+) homeostasis in planta and by this function modulates K(+) nutrient status. Mutations that disrupt AtHKT1 function suppress NaCl sensitivity of sos1-1 and sos2-2, as well as of sos3-1 seedlings grown in vitro and plants grown in controlled environmental conditions. hkt1 suppression of sos3-1 NaCl sensitivity is li...

The lens of the toad Bufo marinus, like that of mammals, slowly gains Na and loses K when incubated in vitro. This process is facilitated by a low temperature (5° C), iodoacetate, cyanide, or ouabain. The ratio of Na/K exchange is about 1.5. Decapsulation of the lens (following brief incubation in collagenase) did not change its ionic content. Such lenses maintained their Na levels in vitro bet...

Previous studies have demonstrated that electrically induced seizures in rat result in an increased brain intracellular sodium which can be decreased by treatment with sodium diphenylhydantoin (DPH). The correlation of cation transport with membrane-oriented sodium-potassium-adenosine triphosphatase (Na-K-ATPase) prompted an investigation of the effect of DPH upon ATPase enzyme activity.Rat cer...

Resealed human red blood cell ghosts were prepared to contain a range of ADP concentrations at fixed ATP concentrations and vice versa. ATP/ADP ratios ranging from approximately 0.2 to 50 were set and maintained (for up to 45 min) in this system. ATP and ADP concentrations were controlled by the addition of either a phosphoarginine- or phosphocreatine-based regenerating system. Ouabain-sensitiv...

Two methods of detecting early inapparent myocardial infarcts have been studied and their value in diagnostic practice compared. The better method proved to be the determination of the potassium to sodium ratio (ionic ratio) which falls in infarcted tissue within minutes of the onset of anoxia. The second method was nitro blue tetrazolium staining of gross sections of myocardium which revealed ...

salinity problem is continuously increasing in the arid and semi-arid regions of iran. to effectively utilize germplasm resources in breeding, it is necessary to characterize and evaluate genotypes for the desirable traits and as well for salinity tolerance. salinity tolerance of 80 wheat landraces from different parts of iran was studied in two steps. at first, the degree of salnity tolerance ...

Ethanol intoxication resulted in high extent of lipid peroxidation, and reduction in antioxidant defenses (decreased GSH, GSH/GSSG ratio, and catalase, SOD and GPx activities) and (Na+/K+)-ATPase activity in kidney. Alpha-tocopherol treatment effectively protected kidney from ethanol induced oxidative challenge and improved renal (Na+/K+)-ATPase activity. Ethanol induced oxidative stress in the...