1. Isolated surviving frog skin, when bathed with the same kind of diluted Ringer's solution on both sides, shows a negative correlation between net active salt uptake by the epithelium and spontaneous skin potential. Average values of 0.15 to 0.86 microeq. x hr.(-1) x cm.(-2) were measured and correlated with average skin potentials ranging from 107 to 25 mv. 2. Sodium uptake exceeded chloride...

Sparks D.L., Martens D.C., Zelazny L. W.: Plant Uptake and Leaching of applied and indigenous Potassium in Dothan Soils. Sparks D.L., Zelazny L. W., Martens D.C.: Kinetics of Potassium Exchange in a Paleudult from the Coastal Plain of Virginia. Sparks D. L., Zelazny L. W., Martens D. C.: Kinetics of Potassium Desorption in Soils using Miscible Displacement, Sparks D.L.: Chemistry of Soil Potass...

Treatment of erythrocytes with the divalent cation ionophore A23187 results in net uptake of calcium and a calcium-dependent decrease in cellular potassium content and cell volume. These changes in membrane properties are associated with a selective stimulation of fatty acid incorporation into membrane phosphatidylethanolamine (PE). In this study the relationship between this selective stimulat...

to differentiation of the spermatozoon to the mature motile condition. During differentiation, striking variations occur not only in cell shape but also in the ionic composition of the developing spermatozoa and their surrounding media, specifically in the ratio of sodium to potassium (Cragle, Salisbury & Muntz, 1958). The membrane potential (Em) of cells isolated from mouse testis is dependent...

Calcium uptake produced by a potassium contracture in isolated frog twitch fibers was 6.7 +/- 0.8 pmol in 0.7 cm of fiber (mean +/- SEM, 21 observations) in the presence of 30 microM D600. When potassium was applied to fibers paralyzed by the combination of 30 microM D600, cold, and a prior contracture, the calcium uptake fell to 3.0 +/- 0.7 pmol (11): the fibers were soaked in 45Ca in sodium R...

The distribution of sodium and potassium throughout corn (Zea mays L. [A632 x Crows 3640] x Oh 43) plants is not simply a matter of uptake by cortical cells and irreversible delivery to the xylem for upward transport. We show that sodium, but not potassium, accumulates in the mesocotyl of corn seedlings grown on NaCl medium. Upon transfer to NaCl-free medium, total sodium is reduced by export t...

Inflow of potassium ions into the alga Hydrodictyon reticulatum is reduced in the dark, the reduction being accompanied by a change in the selectivity pattern with respect to alkali metal ions, observed in competition experiments and evaluated by the gnostic analysis as described by Kovanic. This suggests that in the light a special mechanism of potassium uptake with a characteristic selectivit...

Streptococcus bovis JB1 cells were able to transport serine, threonine, or alanine, but only when they were incubated in sodium buffers. If glucose-energized cells were washed in potassium phosphate and suspended in potassium phosphate buffer, there was no detectable uptake. Cells deenergized with 2-deoxyglucose and incubated in sodium phosphate buffer were still able to transport serine, and t...

We studied the requirement for potassium and for potassium transport activity for the biotechnologically important bacterium Corynebacterium glutamicum, which is used for large-scale production of amino acids. Different from many other bacteria, at alkaline or neutral pH, C. glutamicum is able to grow without the addition of potassium, resulting in very low cytoplasmic potassium concentrations....

Saccharomyces cerevisiae cells containing a deletion of TRK1, the gene encoding the high affinity potassium transporter, retain only low affinity uptake of this ion and consequently lose the ability to grow in media containing low levels (0.2 mM) of potassium. Using a trk1 delta strain, we selected spontaneous Trk+ pseudorevertants that regained the ability to grow on low concentrations of pota...