Effect of ozone. On pyridine nucleotide reduction and phosphorylation of Euglena gracilis.

Abstract

Fumigation of a Euglena gracilis suspension for one hour with 0.80 ppm ozone in the absence of light does not affect the concentration of reduced pyridine nucleotide (NADH) in the cells. Oxidative phosphorylation is increased by 9.4%, following fumigation with 0.80 ppm ozone; its efficiency (P/O ratio) remains unchanged. Exposure of Euglena cells to ozone (0.80 ppm) in the presence of light diminishes the rate of NADH formation by 9% to 12% when compared with samples treated with pure air. Photosynthetic phosphorylation of Euglena samples treated with 0.80 ppm ozone is diminished by 3.6%. Data that were obtained following fumigation with ozone in the dark suggest the formation of modified cell structures. Results obtained following fumigation with ozone in the presence of light explain the inhibitory effect of ozone on the rate of photosynthesis of E gracilis in more detail.