A new chemically mutagenic mutant of Synechococcus PCC7942 named high-CO2 re-quiring mutant, which could grow at 4% CO2 but could not grow at air levels of CO2, was isolated. Com-parative studies on some physiological...A new chemically mutagenic mutant of Synechococcus PCC7942 named high-CO2 re-quiring mutant, which could grow at 4% CO2 but could not grow at air levels of CO2, was isolated. Com-parative studies on some physiological aspects of the mutant and high-cO2 growing cells (growing at 4%CO2 ) were conducted. The result showed that the mutant had lower growing rate, about 1/40th photosyn-thetic affinity to inorganic carbon, 25% lower carbonic anhydrase (CA) activity, lower quenching rate ofchlorophyll fluoresence, and about 1/2 alkalinization rate of the medium. The CA activity responses ofthe two types of cells to different concentrations of CO2 were determined. Upon the addition of inorganiccarbon (Ci), the rate of active Ci uptake described by the rate of chlorophyll fluorescence quenching ofthe mutant was obviously lower compared with that of the high-CO2 growing cells; the size of the internalinorganic carbon pool size determined by the extent of fluorescence quenching Of the mutant was alsosmaller.展开更多
文摘A new chemically mutagenic mutant of Synechococcus PCC7942 named high-CO2 re-quiring mutant, which could grow at 4% CO2 but could not grow at air levels of CO2, was isolated. Com-parative studies on some physiological aspects of the mutant and high-cO2 growing cells (growing at 4%CO2 ) were conducted. The result showed that the mutant had lower growing rate, about 1/40th photosyn-thetic affinity to inorganic carbon, 25% lower carbonic anhydrase (CA) activity, lower quenching rate ofchlorophyll fluoresence, and about 1/2 alkalinization rate of the medium. The CA activity responses ofthe two types of cells to different concentrations of CO2 were determined. Upon the addition of inorganiccarbon (Ci), the rate of active Ci uptake described by the rate of chlorophyll fluorescence quenching ofthe mutant was obviously lower compared with that of the high-CO2 growing cells; the size of the internalinorganic carbon pool size determined by the extent of fluorescence quenching Of the mutant was alsosmaller.
