The incidence of micronucleoli in the course of terminal differentiation of human erythroblasts was studied by the cytochemical procedures for demonstration of RNA and characteristic proteins of interphase AgNORs. The last dividing stages of the erythroid lineage--polychromatophylic erythroblasts--characterized by the presence of micronucleoli exhibited significantly larger values of the nucleolar coefficient in specimens stained for AgNOR proteins than in those stained for RNA. In addition, both these and terminal non-dividing nucleated stages of the erythroid lineage--orthochromatic erythroblasts--possessed micronucleoli after staining for RNA in a much smaller percentage of cells than after staining for AgNOR proteins. Thus, both these observations indicate that micronucleoli in the course of terminal maturation of erythroblasts apparently lose the nucleolar RNA detectable by the light microscopic cytochemistry. In addition, silver-stained micronucleoli--nucleolar remnants--were also noted in erythroblasts expelling the nucleus.
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Folia Biol (Praha)
April 2001
Clinical Department, Institute of Hematology and Blood Transfusion, Prague, Czech Republic.
Anat Embryol (Berl)
June 1994
Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague.
The primitive erythroid line cells of chick embryos were studied during embryonic days 2-14 by means of a cytochemical method to investigate the appearance and frequency of the main nucleolar types. The populations of erythroblasts and erythrocytes were classified according to the presence of functionally dominant nucleoli in their nuclei. In the course of primitive erythroid cell differentiation and maturation, compact nucleoli and nucleoli with nucleolonemas (both supposed to be RNA biosynthetically active) were gradually replaced by ring-shaped nucleoli and finally by micronucleoli reflecting the reversible and irreversible inhibition of RNA synthesis, respectively.
View Article and Find Full Text PDFJ Hered
August 1991
Department of Poultry and Avian Sciences, Cornell University, Ithaca, New York 14853.
Variations in nucleolar size are common in animals and man, yet the basis and significance of this variation are not well understood. In this report, we describe the generation de novo of individuals that express nucleolar size variations (polymorphisms) and the underlying basis for this phenotype in a vertebrate animal system (Gallus domesticus). Individuals that express nucleolar size polymorphisms were produced from mating chickens trisomic for the nucleolar organizer (NO) chromosome; 10%-18% of progeny demonstrated nucleolar polymorphisms.
View Article and Find Full Text PDFIn antheridial filaments of Chara vulgaris the number of nucleoli within a single cell nucleus ranges from 3 to 12. The sizes of nucleoli vary from 0.2 to 3.
View Article and Find Full Text PDFFolia Histochem Cytobiol
August 1984
The aim of the study was to observe the changes of the nucleoli index of lymphocytes in the blood of eight-week-old chickens which, after a 15-19 day quantitatively limited diet, were administered intravenously a single dose of 1 IU ACTH per 100 g body weight of a chicken. The experimental chickens, as compared with the control ones, showed an increased nucleolar index of lymphocytes (percent ratio of lymphocytes with active nucleoli to the per cent of lymphocytes with micronucleoli). The value of this index was inversely proportional to that calculated from mean weights of lymphatic organs and suprarenal glands, used for assessment of stress in chickens.
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