The fine structure of cleavage, blastula, and gastrula stages of Fundulus heteroclitus was investigated. Cleavage blastomeres are relatively unspecialized, containing few or poorly developed organelles. Beginning in blastula stages, signs of differentiation were noted, including development of the endoplasmic reticulum and Golgi apparatus and appearance of a primary nucleolus and polyribosomes. More extensive structural specializations occur in gastrula stages, including further development of the endoplasmic reticulum and appearance of a granular component in the nucleolus. These changes are associated with cell differentiation and an increased capacity for protein synthesis, and may be preparatory to subsequent histogenesis. The periblast is a continuous syncytial cytoplasmic layer located between the blastodisc and yolk and is formed during late cleavage by incomplete division of the cytoplasm of the blastodisc. Cytoplasmic projections extend from the periblast (and from the basal region of cleavage blastomeres prior to formation of the periblast) into the yolk and function in uptake of yolk material in the absence of pinocytosis. Yolk material appears to be digested by the periblast and transferred into the segmentation cavity where it is available to the blastomeres. Protein granules, lipid droplets, glycogen, crystalline arrays, and multivesicular bodies are related to food storage and utilization by blastomeres. The yolk gel layer enclosing the yolk sphere was found to be a thin layer of cytoplasm continuous with the margin of the periblast and is renamed the yolk cytoplasmic layer.
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1 January 1967
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January 01 1967
A FINE STRUCTURAL STUDY OF CYTODIFFERENTIATION DURING CLEAVAGE, BLASTULA, AND GASTRULA STAGES OF FUNDULUS HETEROCLITUS
Thomas L. Lentz,
Thomas L. Lentz
From the Departments of Anatomy and Biology, Yale University, New Haven, Connecticut, and The Marine Biological Laboratory, Woods Hole, Massachusetts
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J. P. Trinkaus
J. P. Trinkaus
From the Departments of Anatomy and Biology, Yale University, New Haven, Connecticut, and The Marine Biological Laboratory, Woods Hole, Massachusetts
Search for other works by this author on:
Thomas L. Lentz
From the Departments of Anatomy and Biology, Yale University, New Haven, Connecticut, and The Marine Biological Laboratory, Woods Hole, Massachusetts
J. P. Trinkaus
From the Departments of Anatomy and Biology, Yale University, New Haven, Connecticut, and The Marine Biological Laboratory, Woods Hole, Massachusetts
Received:
July 05 1966
Online ISSN: 1540-8140
Print ISSN: 0021-9525
Copyright © 1967 by The Rockefeller University Press
1967
J Cell Biol (1967) 32 (1): 121–138.
Article history
Received:
July 05 1966
Citation
Thomas L. Lentz, J. P. Trinkaus; A FINE STRUCTURAL STUDY OF CYTODIFFERENTIATION DURING CLEAVAGE, BLASTULA, AND GASTRULA STAGES OF FUNDULUS HETEROCLITUS . J Cell Biol 1 January 1967; 32 (1): 121–138. doi: https://doi.org/10.1083/jcb.32.1.121
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