Interactions between respiration and inorganic phosphate uptake in phosphate-limited cells of Chlamydomonas reinhardtii |
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Authors: | Harold G. Weger |
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Affiliation: | Dept of Biology. Univ. of Regina, Regina, SK, S4S 0A2, Canada. |
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Abstract: | Phosphate addition to P-limited cells of Chlamydomonas reinhardtii resulted in an immediate increase in the rate of respiratory O2 consumption. The respiration rate continued to increase for several minutes after the addition of P1. Similar patterns of P1 stimulation of respiratory O2 consumption were observed in the presence of cyanide (cytochrome oxidase inhibitor) and propyl gallate (alternative oxidase inhibitor). Stimulation of O2 consumption was accompanied by rapid changes in levels of glycolytic intermediates. These changes were consistent with activation of ATP-dependent phosphofructokinase and pyruvate kinase. The adenylate pool exhibited only minor perturbations, P1, uptake resulted in extracellular acidification, which continued for several minutes after the exhaustion of added P1, whereas exhaustion of extracellular P1 resulted in a rapid decline in the O2 consumption rate. These results are consistent with control of respiration in P-limited cells occurring largely at the level of glycolysis. |
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Keywords: | Chlamydomonas reinhardtii glycolysis metabolites O2 consumption pH phosphate respiration |
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