Effect of high oxygen tension on potassium retentivity and colony formation of baker's yeast.

The ability of yeast cells to retain potassium and to form colonies was studied after exposure to pressures ranging from 2 to 143 atmospheres of oxygen. The investigations allow comparison of these responses with those found after x-ray exposure. Exposure to 2 to 8 atmospheres of oxygen for 2, 20, and 40 hours showed decreased potassium leakage as measured by an elution technique.

The production of hydrogen peroxide by high oxygen pressures.

Hydrogen peroxide is formed in solutions of glutathione exposed to oxygen. This hydrogen peroxide or its precursors will decrease the viscosity of polymers like desoxyribonucleic acid and sodium alginate. Further knowledge of the mechanism of these chemical effects of oxygen might further the understanding of the biological effects of oxygen.

Experiments on the role of potassium in the blocking of neuromuscular transmission by curare and other drugs.

1. Experiments with perfused frog muscles and with isolated frog muscles immersed in Ringer's solution have failed to show any effect of curare in liberating potassium from muscle tissue. This makes it difficult to suppose that the paralytic effect of curare can be attributed to cation exchange between curare and K whereby a labile potassium compound needed for stimulation is removed from the neuromuscular junction.

The loss of potassium from frog nerves in anoxia and other conditions.

1. Frog nerves immersed in Ringer's solution lose on the average 23 per cent more potassium if the solution is equilibrated with pure nitrogen than if equilibrated with oxygen. 2.