Inhibition of cell division by ultraviolet irradiated unsaturated fatty acid

Ultraviolet irradiation of eggs of Chaetopterus pergamentaceous resulted in the formation of lipid peroxides as measured by the thiobarbituric color reaction. Aqueous extracts of ultraviolet irradiated methyl linolenate inhibited cleavage, reversed furrow formation, and reduced spindle size. These effects were also brought about by ultraviolet irradiation. Irradiated methyl linolenate also reduced the size of the fully formed spindle of the eggs of Lytechinus variegatus. It is suggested that at least a part of the action of ultraviolet irradiation is mediated through the formation of lipid peroxides.