ENHANCEMENT OF INTRACELLULAR PROLINE LEVEL IN CELLS OF ANACYSTIS NIDULANS (CYANOBACTERIA) EXPOSED TO DELETERIOUS CONCENTRATIONS OF COPPER1 |
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Authors: | Jiunn-Tzong Wu Shih-Chieh Chang Kuang-Sin Chen |
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Abstract: | The intracellular proline level in Anacystis nidulans cells was enhanced when the cells were exposed to sublethal concentrations of Cu2+; the degree of enhancement was positively related to the concentration of Cu2+. Analysis by high-performance liquid chromatography confirmed that the enhancement of proline levels was the most pronounced change in the composition of the free amino acid pool during copper treatment. A direct supply of exogenous proline to the cultures lowered the inhibitory influence of Cu2+on the growth of cells. Further experiments showed that the supply of exogenous proline lowered the leakage of potassium ions from cells exposed to deleterious concentrations of Cu2+. The inhibition of potassium leakage was particularly pronounced when proline was supplied prior to Cu2+treatment. The present study suggests that enhanced proline protects cell membranes from being affected by deleterious concentrations of Cu2+. |
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Keywords: | amino acids Anacystis nidulans copper cyanobacteria potassium leakage proline accumulation stress protectant |
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