title: [Electron microscopic study of the chromonema and chromomeres in mitotic and interphase chromosomes].
abstract: Study of ultrathin sections of the Chinese hamster normal cells and cells treated with solutions containing decreasing concentrations of Ca++ and Mg++ ions revealed several discrete levels of DNP-fibres organization in mitotic and interphase chromosomes. In total Ca++ and Mg++ concentrations from 4 mM to 0.3 mM, the chromosomes are formed by filamentous elements or chromonema of 100-nm diameter. During gradual decrease of Ca++ concentration to 0.2-0.1 mM the chromosomes decondensate into discrete chromatin structures--chromomeres. In decondensation, the chromomeres acquire a "rosette-like" structure with an electron dense core and DNP-fibers radiating from it. Levels of DNP compactization in chromosomes are supposed to be as follows: the nucleosomal fibres of 10-nm diameter, nucleomeric fibres of 25-nm diameter and chromonema, i.e. a filamentous structure of 100-nm diameter consisting of chromomeres.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002842:Chromatids / Q000648:ultrastructure*; D002843:Chromatin / Q000648:ultrastructure; D002875:Chromosomes / Q000648:ultrastructure*; D006224:Cricetinae; D003412:Cricetulus; D003852:Deoxyribonucleoproteins / Q000032:analysis; D007399:Interphase; D008854:Microscopy, Electron; D008938:Mitosis
chemical_list: D002843:Chromatin; D003852:Deoxyribonucleoproteins
vernacular_title: Elektronno-mikroskopicheskoe izuchenie khromonemy i khromomerov v mitoticheskikh i interfaznykh khromosomakh.