39 research outputs found

    Light induced calcium binding to mangrove PS II particles

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    AbstractA combination calcium selective and oxygen electrode system was used to measure the Ca2+ and O2 concentrations of a solution surrounding mangrove PS II particles. Concomitant uptake of Ca2+ and oxygen evolution in the light were observed. The Ca2+ bound during the light was released in a subsequent dark period. The Ca2+ binding was dependent on both chlorophyll and Ca2+ concentrations. Up to 3000 Ca2+ were calculated to be bound per reaction centre

    Effect of depolarizing concentrations of potassium on calcium uptake and metabolism in rat liver

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    AbstractExposure of perfused livers of fed rats to 60 mM K+ induces rapid responses in the Ca2+-sensitive metabolic events, glycogenolysis, cytoplasmic and mitochondrial NADH/NAD ratios and octanoate oxidation. All increase within 45 s of K+ addition. Metabolic responses were not observed following K+ addition to livers perfused in the absence of added Ca2+. Movements of Ca2+ into the liver were suggested from experiments in which 45Ca2+ uptake was measured. The Ca2+ antagonists verapamil, diltiazem and Ni2+ essentially abolished changes to tissue metabolism and Ca2+ fluxes induced by K+ addition. K+-induced changes were consistent with Ca2+ channel activiation.LiverPotassium depolarizationGlycogenolysisCalcium antagonis
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