Publications by authors named "Shigeyoshi Miyashiro"
Adenosine at concentrations greater than 6 μg/ml halted embryonic development of the starfish Asterina pectinifera specifically at the 256-cell stage which corresponds to the onset of blastulation. When a fertilized egg was cultured continuously in sea water containing adenosine from fertilization, a gradual increase in intracellular concentrations of free adenosine was observed before a cessation of development took place. On the other hand, intracellular concentrations of ATP, ADP and AMP in the embryo cultured in sea water containing adenosine were nearly the same as those of an embryo cultured in sea water without adenosine.
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- Iturin A-2, a cyclic peptide from Bacillus subtilis, inhibits cell division in starfish fertilized eggs, leading to non-cleaving eggs filled with embryonic nuclei in shared cytoplasm.
- Despite this inhibition, the eggs continue to synthesize DNA, RNA, and proteins at rates consistent with normal embryos until the blastulation stage.
- Treatment with iturin A-2 also disrupts the oocytes’ response to maturation-inducing substances, indicating that it affects membrane function—specifically, the ability to form a cleavage furrow during division.