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The Uptake and Metabolism of Sulphate in Scenedesmus as Influenced by Citrate, Carbon Dioxide, and Metabolic Inhibitors
Author(s) -
Kylin Anders
Publication year - 1967
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1967.tb07151.x
Subject(s) - selenate , chemistry , phosphate , metabolism , selenium , biochemistry , carbon dioxide , chlorella , carboxylation , scenedesmus , decarboxylation , inorganic chemistry , environmental chemistry , algae , botany , biology , organic chemistry , catalysis
The incorporation of sulphur from external sulphate into different fractions was studied in cells with a P content of 0.6 to 1 mg/g fresh weight as against 3 to 5 mg/g fresh weight in normal cells. — There is a flat and broad optimum for the action of pH in the region between 5.7 and 7. — In most cases, citrate inhibits the uptake of sulphur. — Five per cent CO 2 in the air enhances the incorporation of S. It is suggested that the effects of CO 2 may well be exerted by way of the carboxylation and decarboxylation mechanisms in the cells. — Selenate inhibits the formation of DNA‐S and protein S more than that of lipid S, but the main effect in both cases seems to be in an early step of the assimilation of sulphate. In the absence of external phosphate, the inhibition is counteracted by CO 2 , especially in darkness. Phosphate enhances the action of selenate on the organic S fractions, and in its presence CO 2 and darkness make the inhibition more pronounced. — Without P in the medium, the effects of selenate on uptake into the inorganic sulphate fraction are smaller than when the organic fractions are concerned. In the presence of CO 2 even stimulations due to selenate have been observed. External phosphate brings the inhibition of uptake into cellular SO 4 2‐ to the same level as found in the case of organic S. More than one pathway for the uptake as SO 4 2‐ seem possible. — Anaerobiosis and menadione affect the organic S fractions more than the sulphate; 2,4‐dinitrophenol has a more uniform action all over the field.