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Topology of the germ plasm and development of primordial germ cells in inverted amphibian eggsInverted Xenopus eggs have reduced numbers of primordial germ cells (PGCs). The extent of the reduction varies from spawning to spawning. Histologic examination revealed that PGC counts were lowest in inverted eggs which displayed the greatest amount of shift in the vegetal mass of large yolk platelets, although the germ plasm itself always remained localized in the egg's original vegetal hemisphere. Even at blastulation the germ plasm continued to be localized in the egg's original vegetal hemisphere. In many cases, however, it was confined to the periphery of the embryo, which probably accounts for the reduced PGC number in some tadpoles. In other cases it may have been dispersed and therefore not detectable in histologic analyses. Although the altered site of involution in inverted embryos did not influence PGC development, subsequent cell movement patterns apparently did. Those embryos which displayed the largest degree of pattern reversal at the tail-bud stage also exhibited the most extreme reduction in PGC numbers. A brief cold shock (4 degrees C, 10 min) prior to first cleavage leads to a further reduction in PGC numbers in inverted embryos, probably as a result of the displacement of the germ plasm away from its original vegetal pole location.
Document ID
20040120819
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Wakahara, M.
(Indiana University Bloomington 47405, United States)
Neff, A. W.
Malacinski, G. M.
Date Acquired
August 22, 2013
Publication Date
May 1, 1984
Publication Information
Publication: Differentiation; research in biological diversity
Volume: 26
Issue: 3
ISSN: 0301-4681
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAGW-60
Distribution Limits
Public
Copyright
Other

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