Alpha-Particle Bombardment of the Habrobracon Egg: II. Response of the Cytoplasm

Abstract
Alpha-radiation was used to kill newly laid Habrobracon eggs by inactivation of the cytoplasm. Cytoplasmic inactivation is kinetically and morphologically distinct from nuclear inactivation. The egg nucleus is inactivated by one alpha-particle; the 50% lethal dose is approximately 16 x 106 alpha-particles per egg when the cytoplasm is irradiated. Death occurs late in development when the cytoplasm is alpha-irradiated, and in most respects the morphology of the dead embryos resembles that of cytoplasmic ultraviolet irradiation.