An Attempt to Stimulate Cell Division in Saccharomyces cerevisiae with Weak Ultraviolet Light

Abstract
Liquid cultures of the yeast Saccharomyces cerevisiae were irradiated with weak light having irradiances ranging from ca. 1 .times. 102 to 5 .times. 109 photons cm-2 s-1 and at wavelengths ranging from 200 to 700 nm. When particular care was taken to control the temperature of the cultures and the flow rate of oxygen, no evidence was obtained for stimulation of either yeast growth or division by the incident light. These results do not support the cliams of early workers that very low intensity uv light can stimulate cell division in living organisms.