On X-ray Sensitivity in Xenopus Embryogenesis.

We examined the effects of X-ray irradiation on Xenopus laevis , focusing on pre- and post-fertilization exposure. We applied X-ray doses of 10, 50, 100, 250, and 500 Gy. Fifty percent of the 360 eggs irradiated at 250 Gy failed to fertilize, while fertilized eggs developed normally until the gastrula stage. Doses ranging from 10 to 250 Gy caused developmental anomalies. High mortality rates were observed at doses of 100 to 500 Gy. Post-fertilization irradiation at 50 to 100 Gy resulted in 100% lethality, while exposure to 10 Gy led to only 13% lethality, although both exposure levels produced similar types of developmental anomalies compared to pre-fertilization irradiation. This study highlights how the timing and intensity of exposure critically affect embryo viability, especially during the sensitive stages of fertilization and gastrulation. We establish the necessary and sufficient dosage to further investigate the molecular mechanisms of X-ray damage to DNA and protein.