Excretion of glycolate during synchronous culture of Ankistrodesmus braunii in the presence of disalicylidenepropanediamine or hydroxypyridinemethanesulfonate

The rate of excretion of glycolate by the unicellular greenalga Ankistrodesmus braunii changes during its life cycle. Itis high in the main growth phase during the light period witha maximum 6 hr after the start of illumination, and low duringthe period of cell division in the dark. The glycolate excretion is stimulated by DSPD and HPMS, whilethe total ¹⁴CO₂-fixation is inhibited by DSPD and enhanced byHPMS. Changes in the effects of DSPD and HPMS on glycolate excretionas well as on photosynthetic ¹⁴CO₂-fixation during the courseof the algal life cycle were followed using the technique ofsynchronous culture. How far the change of glycolate excretion is due to a changeof glycolate oxidase activity during the life cycle and to achange of C₂-supply from the carbon reduction cycle is discussed.The effect of DSPD on glycolate excretion suggests a participationof ferredoxin in the glycolate pathway. (Received August 10, 1968; )