Recovery from Radiation-Induced Delay of Cleavage in Gametes of Arbacia punctulata

Abstract

A decrease in delay of cleavage, when irradiated sperm fom Arbacia punctulata were allowed to "recover" inside eggs, occurred when cell division was interrupted by the removal of oxygen soon after fertilization. The recovery mechanisms in irradiated eggs of this species before and after fertilization have been compared and appear to differ.

Post-fertilization Dark Recovery of U.V.-irradiated Sea-urchin Sperm

“…-irradiation compared with the recovery from y-irradiation are difficult to interpret in the absence of detailed information about the dose-response, the nature of the chemical lesions, and the rates of recovery. The rate of recovery from yradiation-induced mitotic delay does not vary with dose (Failla 1965, 1969, andunpublished data) . In the present experiments, a greater percentage of recovery from u .v .-induced mitotic delay occurred at the higher doses (see the table) .…”

“…Failla (1962 b) demonstrated post-fertilization recovery of y-irradiated sperm and eggs when the mitotic cycle was interrupted by anoxia. The occurrence of post-fertilization recovery is also suggested by the observation that the sensitivity to x-ray-induced mitotic delay increases during the early portion of the mitotic cycle (Henshaw and Cohen 1940, Failla 1969) . In contrast, there are long periods of uniform sensitivity to u.v .-induced mitotic delay during the cell-division cycle (Blum andPrice 1950, Rustad 1960) .…”

“…This type of post-fertilization recovery has been studied extensively in eggs inseminated with y-irradiated sperm during the time that the first mitotic cycle is interrupted by making the eggs anoxic (see Failla 1962b, 1965, 1969, Failla and Rustad 1970 . A similar recovery in eggs fertilized with u .v.-irradiated sperm would suggest that seaurchin cells contain enzymes which can repair both types of lesions, even though repair of damage to u .v.-irradiated eggs cannot be demonstrated .…”

“…In unfertilized sea-urchin eggs there is a time-dependent recovery from the damage by x-or y-radiation which leads to mitotic delay (Henshaw 1932, Miwa, Yamashita and Mori 1939, Failla 1962 . However, these eggs do not appear to be capable of`dark recovery' from u .v .-induced mitotic delay during the interval between irradiation and fertilization (cf .…”

Nuclear-Cytoplasmic Relations in the Mitosis of Sea Urchin Eggs. Ii. The Division Times of Whole Eggs and Haploid and Diploid Half-Eggs

“…It seems more likely that the cytoplasmic volume or surface area influences the rate of recovery from radiation damage . Both (Henshaw, 1932) and fertilized eggs (Failla, 1962) exhibit recovery from the damage by X-rays which leads to mitotic delay. Normally, little protein synthesis occurs in the egg until shortly after fertilization (reviewed by Tyler 1966 ;Gross, 1967), but y-irradiation stimulates the incorporation of amino acids into proteins in unfertilized eggs (Rustad, 1967) .…”