title: Effects of soluble fractions from untreated and SiO2-treated subcellular particles of macrophages on nucleic acid metabolism in isolated nuclei of experimental granulation tissue.
abstract: Nuclei isolated from proliferating granulation tissue were incubated with 20 000 g supernatants from untreated and SiO2-treated subcellular particles of rat peritoneal macrophages in the presence of radioactive nucleic acid precursors. The supernatant from SiO2-treated subcellular particles increased the incorporation of [3H]CTP into nuclear RNA maximally by 26% at 5 min, and that of [methyl-3H]dTTP into DNA by 16% at 20 min. The release of radioactivity from labeled DNA was suppressed simultaneously. An RNase preparation from rat peritoneal macrophages enhanced the release of radioactivity from labeled DNA similarly as the soluble fraction from untreated subcellular particles of macrophages. The results suggest that the effects of the soluble fractions upon DNA metabolism of granuloma cells are at least partly independent of the effects on RNA metabolism and that the soluble fraction from SiO2-treated subcellular particles of macrophages stabilizes DNA through inhibition of nuclease activity.
mesh_terms: D000818:Animals; D002457:Cell Extracts / Q000494:pharmacology; D002467:Cell Nucleus / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D006097:Granulation Tissue / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D012313:RNA / Q000378:metabolism*; D051381:Rats; D012822:Silicon Dioxide / Q000494:pharmacology*; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D002457:Cell Extracts; D012313:RNA; D012822:Silicon Dioxide; D004247:DNA