Beobachtungen zur Struktur des Nucleolus in normalen Zellen sowie in Tumorzellen

Nucleolus and Chromosomes in <i>Euglena gracilis</i>

“…The author's observations on the cells of Spirogyra (Chlorophyceae) (108,109), confirmed early interpretations of the chromosomal nature of the Feulgen positive nucleolar structures (61, 87,88,89), but the light microscopy used did not resolve details of the nucleolar struc tures containing DNA and failed to disclose the expected association of intranucleolar DNA with extranucleolar DNA (chromosomes) (Figs. 1-8).…”

“…Nucleolar proteins are laid down as short, coiled fibrils almost at right angles with the organizer and intimately associated with it. These short nucleolar fibrils, which are depolymerizable RNAse and proteinases, may correspond to the ground nucleolar material described by light microscopy under the name of "pars amorpha" and known to b e Feulgen-negative and pyroninophilic (50, 51, 61, 62, 64, 87,88,103,108,109,110,133).…”

“…Feulgen positive structures have been described inside the nucleolus of a variety of cell types (7,15,16,17,18,36,43,84,87,88,105,108,109,110,139,141); and a "nu cleolar" DNA fraction has been reported in chemical analysis of isolated nucleoli (19,29,30,44,104,106,130,136,149). This chemically identified nucleolar DNA has been regarded as contamination by chromatin; however, nucleolar incorporation of DNA precursors has been shown to occur (65, 68, 69, 121) and a nucleolar constituent has been demonstrated to be hydrolyzable by DNAse (15,108,109,110,139,141).…”