engleski

Effect of metal ions on the liver nuclei

The influence of metal ions Mg (0, 1mg/L), Pb (0, 3mg/L) and Se (0, 1 mg/L) on liver cells of carps (Cyprinus carpio L.) was investigated during the period of 80 days. Already after 7 days of treatment a major increase in number of nuclei with two or three nucleoli was observed. After this initial increase oscillations followed but with a reduction tendency of nucleoli number to untreated group level. Nucleolus is the place of ribosomal RNA production and is especially well developed in cells active in protein synthesis. A larger number of nucleoli suggest metal inducted increase of protein synthesis, probably connected to cells detoxification mechanism. Apart from the nucleolus significant changes were found in nucleus chromatin formation. In all cases metal contamination led to the presence of small heterochromatin grains circularly arranged around nucleus. During prolonged period of contamination grains become bigger and can mask the nucleolus. Heterochromatin present in karyoplasm is regarded to be inactive chromatin, and the increase in number and density of chromatin grains suggests metal inhibitory effect on some genetic activity. It is possible that prolonged contamination causes cells polyploidia that is manifested by the presence of big nuclei.

toxicology; magnesium; lead; selenium; nuclei; morphology

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