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Achromosomal Division of Early Starfish Embryos Cultured in the Presence of Actinomycin D
Author(s) -
Ikegami Susumu,
Ozaki Yoshihiro,
Ooe Yasunori,
Itoh Noriyuki
Publication year - 1991
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1111/j.1440-169x.1991.00193.x
Subject(s) - blastula , starfish , embryo , biology , cell division , blastomere , chromatin , nucleus , microbiology and biotechnology , embryogenesis , rna , dna synthesis , dna , cell , genetics , gastrulation , gene , ecology
Embryos of the starfish Asterina pectinifera were examined for their ability to undergo the early events of embryonic development in the presence of actinomycin D, a most widely used inhibitor of RNA synthesis. Fertilized eggs continued to divide eight or nine times in the presence of 25 μg ml −1 actinomycin D, although delay of development was observed. Chromatin disintegrated in the blastomeres of actinomycin D‐treated embryos specifically at the 32‐cell stage and the nucleus was undetectable at later stages. Before the 32‐cell stage, RNA synthesis was not affected by the presence of actinomycin D whereas DNA synthesis was severely inhibited. The stage when achromosomal divisions cease and embryos begin to die corresponds to the period just before onset of blastulation, suggesting that the presence of the nucleus and chromosomes is a prerequisite for blastula formation and development beyond the 512‐cell stage in this species.