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U.V.‐INDUCED MITOTIC DELAY IN THE SEA URCHIN EGG *
Author(s) -
Rustad Ronald C.
Publication year - 1964
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1964.tb08172.x
Subject(s) - mitosis , sea urchin , centriole , biology , microbiology and biotechnology , acridine orange , spindle apparatus , cytoplasm , biophysics , cell division , cell , genetics , staining
Summary Quantitative studies on u.v. and X‐ray‐induced mitotic delay in the sea urchin egg have been reviewed in order to discuss the nature of the target and the expression of the delay. U.V.‐induced division delay arises from damage to a single system which is also senstitive to X‐rays. Centrifugation can displace a sensitive cytoplasmic component into the centripetal half of the egg. This component may be of secondary importance, because no delay results from the irradiation of a small portion of the cytoplasm with a u.v. microbeam. The primary target is some component of the mitotic apparatus (chromosomes, centrioles, asters or spindle). The multiplication of centrioles is delayed. Data concerning the u.v. action spectra, photoreactivation, and acridine orange damage additivity are consistent with the view that the primary target is a nucleic acid or nucleoprotein. Protein synthesis is required before the cell can pass through the radiation‐sensitive stage. The mitotic delay involves an inhibition of protein synthesis.