ISSN:
1432-0878
Keywords:
Nucleoli
;
Liver cells
;
Ploidy classes
;
Morphometry
;
Numerical data
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary In an investigation comprising different morphometric and numerical data with regard to the nucleoli in smears of isolated parenchymal nuclei of rat liver cells, the following facts were established. 1. Within the three different ploidy classes existing in adult animals, no correlation has been observed between the nucleolar projection area and the number of nucleoli per nucleus. A considerable overlap exists between the numbers of nucleoli in the diploid, tetraploid and octoploid class, so that it is not possible to classify the nuclei of the three classes on the number of nucleoli. 2. The total nucleolar projection area per nucleus in a given ploidy class varies within rather narrow limits, independently of highly variable numbers of individual nucleoli. The means of these nucleolar areas in diploid, tetraploid and octoploid nuclei, showed virtually no deviation from an 1∶2∶4 ratio. 3. The mean numbers of nucleoli in the livers of young adult animals (8 weeks of age) are 2.37, 5.02 and 10.08 for the 2n, 4n and 8n classes, respectively. In embryos and newborn animals, the modal number of nucleoli is 4 in the diploid nucleus, while the first appearing tetraploid and octoploid nuclei, later in development, show at first 8 and 16 nucleoli respectively, the mode of which number falls quickly afterwards. The reduction in nucleolar number, undoubtedly due to fusion, proceeds continuously up to old age: in rats of 21 months, the means are reduced to 1.45 (2n class), 2.66 (4n class) and 5.85 (8n class).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00333998
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