ANAEROBIC RECOVERY OF ASCARIS EGGS FROM X-IRRADIATION

¹ Department of Biology, University of Notre Dame, Notre Dame, Indiana

1. X-irradiation of Ascaris lumbricoides suum eggs produced delay of cell cleavage and reduced the percentage of eggs that completed embryogenesis. The time required for cleavage of irradiated eggs was reduced by an anaerobic treatment after irradiation. The percentage of eggs that completed embryogenesis was increased by the same post-irradiation anaerobiosis. After the anaerobic treatment, eggs must be incubated aerobically since there is no perceptible development under anaerobiosis, although recovery takes place during this period. This recovery is greater at 30° C. than at sub-optimal temperatures.

2. Maximum recovery was obtained for eggs placed immediately after irradiation under anaerobiosis for periods of approximately 15 hours or more at 30° C. If the anaerobic treatment is delayed for 15 hours, the recovery is negligible.

3. Post-irradiation treatment with cyanide also fostered recovery from x-irradiation comparable to that secured with anaerobiosis.

4. Recovery was not due to delay of cleavage: the critical period for recovery took place long before cell division occurred even in air-saturated non-irradiated controls.

5. A cytochrome system in the eggs was demonstrated. The effects of cyanide treatment and anaerobiosis suggest that the mechanism of recovery may involve inhibition of the cytochrome system, which is prevented from participation in the reactions producing the expected deleterious effects of irradiation. There is, however, a positive contribution attributable to anaerobic metabolism, since recovery is greatest at optimal temperatures under anaerobiosis.