title: Ultraviolet light inhibits grey crescent formation on the frog egg.
abstract: Work by others has shown that ultraviolet (UV) irradiation of the vegetal half of the uncleaved frog egg causes defects in neural development. We find that the earliest effect of irradiation ofRana pipiens eggs is to prevent grey crescent formation, the first indication of dorso-ventral polarization of the egg. The UV effect on the grey crescent and on neural development shows similarities in timing, dose-responses, and reversal by cold. We suggest that the UV effect on neural morphogenesis may be caused by the inhibition of cortical-cytoplasmic movement involved in grey crescent formation.
authors.affiliation: Department of Zoology, University of Toronto, 25 Harbord Street, M5S 1A1, Toronto, Ontario, Canada.
authors.forename: Mario E
authors.initials: ME
authors.lastname: Manes
authors.affiliation: Department of Zoology, University of Toronto, 25 Harbord Street, M5S 1A1, Toronto, Ontario, Canada.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Elinson
keywords: Amphibian; Embryology; Grey crescent; Ultraviolet irradiation