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The cytology of the vitellogenic stages of oogenesis in Drosophila melanogaster . II. Ultrastructural investigations on the origin of protein yolk spheres
Author(s) -
Cummings M. R.,
King R. C.
Publication year - 1970
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051300406
Subject(s) - vitellogenesis , yolk , biology , oocyte , ultrastructure , endoplasmic reticulum , microbiology and biotechnology , drosophila melanogaster , oogenesis , vitelline membrane , organelle , vesicle , anatomy , biochemistry , embryo , membrane , ecology , gene
The cytology of the vitellogenic stages in the development of the oocyte of Drosophila melanogaster is described following an electron microscopic study of sections of plastic‐embedded ovaries and single egg chambers. One of the first morphological manifestations of yolk deposition is an infolding of the plasma membrane of the oocyte and the abscission of membranous tubules and vesicles. The protein (alpha) yolk spheres originate along the oocyte periphery from membranous sacs to which are attached membranous tubules. It is assumed that the majority of the protein within the alpha sphere is synthesized by neighboring tubular, rough surfaced endoplasmic reticulum. The other organelles in the ooplasm are described, and their origin and possible roles in vitellogenesis are examined. The relative importance of intra‐ and extra‐ovarian synthesis of yolk protein in different insect species is discussed.