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SEM observation of the External Yolk Syncytial Layer in Blastopore Closure of the Medaka, Oryzias latipes
Author(s) -
KAGEYAMA TETSUO
Publication year - 1985
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.1985.00633.x
Subject(s) - epiboly , oryzias , blastoderm , anatomy , yolk , biology , yolk sac , zebrafish , microbiology and biotechnology , embryogenesis , embryo , gastrulation , fishery , fish <actinopterygii> , biochemistry , gene
The embryonic surface of the teleost, Oryzias latipes , was observed by scanning electron microscopy (SEM) to examine the last phase of epiboly or blastopore closure. The surface of the external yolk syncytial layer (E–YSL), a surface cytoplasmic layer encompassing the yolk sphere situated beyond the blastoderm, was highly undulated with surface folds of random orientation throughout most of epiboly (st. 14–20). Scattered microvilli were observed on the surface of the margin of the yolk plug in st. 18–20. The microvilli, 1 to 6 μm in length, were projected in a bunch at the end of blastopore closure (st. 20–21). The appearance of these microvilli in the last phase of epiboly is discussed with respect to the mechanism of epiboly.