Premium
The centriole in the parthenogenetic and fertilized eggs of Habrobracon juglandis
Author(s) -
Spotkov Elias Morlenn
Publication year - 1938
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.1050620105
Subject(s) - centrosome , centriole , pronucleus , biology , male pronucleus , centrosome cycle , microbiology and biotechnology , germinal vesicle , mitosis , parthenogenesis , spindle pole body , multipolar spindles , metaphase , spindle apparatus , zygote , genetics , oocyte , cell division , cell , embryo , chromosome , embryogenesis , cell cycle , gene
Cyto‐centrosomes containing centrioles but lacking asters originate de novo in great number throughout the ooplasm of Habrobracon eggs during the formation of the first maturation metaphase. These cyto‐centrosomes apparently arise from accessory nuclei which are formed from granules extruded by the germinal vesicle. The accessory nuclei react negatively to the Feulgen nucleal test. Asters similar to those present in artificially parthenogenetic eggs appear around many of the cyto‐centrosomes, thus forming cytasters. These are manifest only after the female pronucleus establishes an association with a cyto‐centrosome, which thus becomes the nuclear centrosome. In the parthenogenetic egg the centriole of the nuclear centrosome is continuous from one cell generation to the next, whereas the centrioles of the cyto‐centrosomes which are unassociated with nuclear material are not perpetuated and disappear during early cleavage. Concerning the origin of the first cleavage centrioles in fertilized eggs, evidence shows that in some ova it is entirely maternal, that is, from two cyto‐centrosomes, one associated with the female pronucleus and occupying one pole of the first mitotic spindle, and the other associated with the male pronucleus and located at the opposite pole; while in other ova it is maternal‐paternal; from two centrosomes, one the sperm centrosome which occupies one pole of the first cleavage spindle, and the other a cyto‐centrosome associated with the female pronucleus and situated at the opposite pole.