The biological clock control over the rate of whole cell oxygen evolution was studied in Euglena gracilis, Klebs strain Z under various conditions that altered calcium availability to the cells. In control cells, the rate of oxygen evolution increased throughout the day, reached a maximum in mid light cycle and then decreased for the remainder of the light/dark cycle. When calcium availability to the cells was altered by exposure to calcium channel antagonists or to antagonists to cell surface calcium, the rate of oxygen evolution was no longer controlled by the biological clock. Instead, the light reactions were uncoupled from the clock. Exposure of cells to neomycin or LiCl, both of which inhibited the inositol trisphosphate calcium signaling system also uncoupled the light reactions from the clock.
Buy this Article