title: The nucleolar chromatin and the secondary constriction.
abstract: We have traced the nucleolar chromatin from early prophase to the metaphase stage. In prophase this chromatin begins to condense and in metaphase it is fully condensed. In mitotic chromosomes, this chromatin remains surrounded by achromatic materials resembling the fibrillar centre. As such this region of the chromosomes appears as a gap or constriction at the light microscope level. The possible role of this achromatic material in relation to nucleologenesis and satellite association has been discussed.
authors.affiliation: Institute of Cell and Tumor Biology, German Cancer Research Centre, Heidelberg.
authors.forename: S
authors.initials: S
authors.lastname: Ghosh
authors.forename: N
authors.initials: N
authors.lastname: Paweletz
mesh_terms: D000818:Animals; D002466:Cell Nucleolus / Q000378:metabolism* / Q000648:ultrastructure; D002843:Chromatin / Q000378:metabolism* / Q000648:ultrastructure; D007614:Macropodidae; D008677:Metaphase / Q000502:physiology; D009697:Nucleolus Organizer Region / Q000648:ultrastructure*; D011418:Prophase / Q000502:physiology
chemical_list: D002843:Chromatin