86Rb Influx Research Articles

Erythrocyte membrane sulfhydryl groups and the active transport of cations.

AbstractParachloromercuribenzenesulfonate (PCMBS) has two opposing effects on the influx of Rb+ into red blood cells. The ouabain‐insensitive component, indicative of passive permeability of the membrane to cations, is increased whereas the ouabain‐sensitive or active transport component is inhibited. The increased passive permeability is paralleled by the action of PCMBS on net K+ efflux into a K+‐free medium. Inhibibition of active transport of Rb+ is paralleled by the inhibitory action of PCMBS on net Na+ efilux from Na+‐rich cells. Both effects are reversed rapidly by the penetrating sulfhydryl compound, cysteine, and considerably more slowly by the non‐penetrating sulfhydryl compound, ovalbumin. Measurements of PCMBS binding and of elution in the presence of cysteine and albumin indicate that only a fraction of the total sulfhydryl groups of the membrane is involved in either the effect on permeability or transport, and that the affected groups are located within the interior of the membrane.

Foliar uptake and translocation of rubidium in bean plants as affected by root absorbed growth regulators

The absorption and subsequent transport of foliar applied Rb86 labeled Rb Cl (10 mM) was studied on bean plants (Phaseolus vulgaris, L. cv. Black Seeded Blue Lake) exposed to physiologically tolerable levels of certain plant growth substances in the solution culture root media. Gibberellin A3 (10-5 M) increased Rb uptake but did not affect total translocation from the treated leaf. Translocation was directed to the upper vegetative parts and markedly reduced to the roots. Foliar influx of Rb and transport to the roots were greatly enhanced by 1-naphthaleneacetic acid (10-6 M) but mobilization of Rb into the leaves and upper stem was reduced. 2-Chloroethyltrimethylammonium chloride (10-3 M) and N,N-dimethylaminosuccinamic acid (3×10-4 M) decreased the mobility of Rb to the upper stem, increased it to the roots, and had no effect on initial uptake. Rb absorption was depressed by 2,4-dichlorobenzyltributylphosphonium chloride (10-5 M) with no effect on subsequent translocation. Both uptake and mobility were strikingly inhibited by N6-benzyladenine (10-6 M).