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At least 19 recordsLinked to original sources

Response of potassium retentivity and survival of yeast to farultraviolet, near-ultraviolet and visible, and x-radiation.

Potassium retentivity and survival of yeast were studied after exposure to various kinds and conditions of irradiation. The radiations used were: 2537 A ultraviolet, 3500 to 4900 A long-ultraviolet and short visible, and 250 kvp(1) x-rays. Both potassium retentivity and survival are decreased by these radiations. The dose-response of survival is about 16 times as sensitive as is potassium retentivity after 2537 A irradiation. Potassium retentivity is about twice as sensitive as survival after irradiation of 3500 to 4900 A. Survival after x-irradiation under aerobic conditions is five times as sensitive as potassium retentivity. Survival of cells irradiated with x-rays under anaerobic conditions was about half as sensitive as under aerobic conditions. The response of potassium retentivity to x-radiation at 25 degrees C. under anaerobic conditions is only slightly affected below 160 kr, at which dose the slope abruptly increases to that obtained under aerobic conditions; lowering the temperature to 0 degrees C. moves this point to about 300 kr. These differential effects are indicative of interaction of radiations with the yeast cell at sites that independently control survival and the retention of potassium.

Cell Survival↗

Photodynamic response in bacteria.

The photodynamic lethal response of Gram negative bacteria was found to be a one event phenomenon as previously reported. However, the kinetics of the lethal response in Gram-positive microorganisms was found to be more complex. The survivor response of the latter was dividable into at least two distinct parts, each of which could be influenced by various environmental and genetic factors. Some correlation was found between sensitivity or resistance to x-ray and ultraviolet radiations and sensitivity or resistance to photodynamic action.

Bacteria↗