Premium
CHANGES IN NUCLEOLI AT MATURATION OF NEWT OOCYTE
Author(s) -
IMOH HIROSHI
Publication year - 1981
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.1981.00033.x
Subject(s) - nucleolus , germinal vesicle , extrachromosomal dna , oocyte , polarity in embryogenesis , microbiology and biotechnology , biology , metaphase , nucleolus organizer region , nucleus , oviduct , ribonucleoprotein , genetics , chromosome , embryo , embryogenesis , rna , gastrulation , genome , endocrinology , gene
Changes in the nucleoli of maturing oocytes and the eggs of Cynops pyrrhogaster were studied with light and electron microscopy. Extrachromosomal nucleoli moved toward the center of the germinal vesicle in response to the maturation stimulus, released presumed ribosomal ribonucleoprotein, and further moved toward the center of the nucleus to form an aggregate with chromosomes which behaved in a similar manner. A few. ball‐shaped nucleolar masses were formed from this aggregate, leaving the chromosomes and probably the extrachromosomal nucleolar organizer. The chromosomes then proceeded to the first meiotic metaphase. The nucleolar masses were surrounded by a layer of mitochondria and became smaller with formation of pinched‐off fragments, which were also surrounded by mitochondria, during the time the egg was moving down the oviduct. Only fragments were observed in the subcortical area of the animal hemisphere of the egg after reaching the lowest part of the oviduct.