Uptake of the lipophilic cation triphenylmethylphosphonium into mesophyll protoplasts of oat (Avena sativa L. cv. "Garry") approaches equilibrium at 3 to 4 hours. The resulting external and internal concentrations are then used with the Nernst equation to obtain a membrane potential of -62 millivolts, inside negative. Potentials calculated in this manner are depolarized by adding 2 mm sodium az...

A tonoplast enriched fraction was obtained from Zea mays L. coleoptiles by isopycnic centrifugation of microsomal membranes in a sucrose step gradient. At the 18/26% interface chloride-stimulated and nitrate-inhibited proton pumping activity coincided with a Mg(2+)-ATP dependent accumulation of 3-O-methyl-d-glucose (OMG) as determined by a membrane filtration technique using (14)C-labeled subst...

Glycidate (2,3-epoxypropionate) increased CO(2) photoassimilation in intact spinach (Spinacia oleracea L.) chloroplasts in the presence of various inhibitors of photosynthesis, including O(2), arsenite, azide, iodo-acetamide, and carbonylcyanide 3-chlorophenylhydrazone. Although the mechanism by which glycidate enhances photosynthesis is obscure, the stimulatory effect cannot be ascribed to eit...

The molecular mechanisms of drug resistance in 19 strains of Vibrio fluvialis isolated from 1998 to 2002 in Kolkata, India, were investigated. Class 1 integrons were detected in eight strains, and four strains were found to carry SXT integrases. In the presence of carbonyl cyanide m-chlorophenylhydrazone or reserpine, all nalidixic acid- and ciprofloxacin-resistant strains became sensitive, sug...

The effect of collapsing the electrochemical proton gradient (AjiH) on [3H]erythromycin and ['4C]azithromycin transport in Haemophilus influenzae ATCC 19418 was studied. The proton gradient and membrane potential were determined from the distribution of [2-14C]dimethadione and rubidium-86, respectively. A.LH was reduced from 124 to 3 mV in EDTA-valinomycin-treated cells at 22°C with 150 mM KCI ...

A polarographic technique was used to demonstrate the rapid restoration by bovine serum albumin of respiratory control to rat liver mitochondria uncoupled with various reagents. Albumin also restored respiratory control to mitochondria isolated from animals treated by injection with an uncoupling reagent and to mitochondria incubated with the reagent prior to the polarographic assay. Albumin wa...

Valinomycin-induced uptake of rubidium by membrane vesicles prepared from Escherichia coli, Staphylococcus QUreus, and Micrococcus denifrificans is analogous in nearly all respects to the transport of sugars or amino acids, or both, by these membrane vesicles. In E. coli membrane vesicles, concentrative rubidium uptake is stimulated maximally by D-lactate and by the artificial electron donor as...