The Photometabolism of glucose in Chlorella

Uniformly labelled radioactive glucose was fed to Chlorella cells in the presence of non-radio­ active carbon dioxide. The concentration of carbon dioxide was varied and the distribution of radio­ activity determined in the light. At low concentrations of carbon dioxide much of the radioactivity appeared in glycollate or derivatives thereform. By contrast, at higher concentrations of carbon dioxide, most of the radioactivity appeared in sucrose. If the concentration of oxygen was increased above that normally present in air, there was relatively more activity in glycollate. The effect of the addition of isoniazid in these conditions was also investigated. It was concluded that glucose fed to Chlorella exogenously is metabolised in the light in Chlorella via sugar phosphate inter­ mediates of the C a l v i n cycle.