Biological effect of high and low oxygen tension,2.

1. With strain L cells in culture the biological effects of oxygen rich environment have been observed with special reference to the cell growth, glycolysis, respiration, incorporation of P³² into Δ10 P and DNA synthesis. 2. Oxygen rich environment produces an increase in the vital activity of the cells at the initial stage of culture, i. e. increased activity of succinoxidase system, low glucose consumption and active cell growth, but in the later stage the activity of the cells is lowered likewise the activity of succinoxidase with the decreased oxidative phosphorylation, and an increase in the uptake of glucose and the enhanced lactic acid production. 3. The most adequate atmosphere for cell proliferation is found to be air though the reason for this remains unsolved. 4. Suppressed cell growth in the later stage of cell culture under the oxygen rich environment is accompanied by the increase of the cells containing smaller amount of DNA, but it is uncertain whether or not the decreased rate in DNA synthesis is responsible for the depressed cell growth.