[USF1 Suppresses Expression of Fibrillar Type I, II, and III Collagen and pNP Adamts-3 in Osteosarcoma Cells].

Collagens are the main components of human tissues. Various regulatory factors and cytokines may influence expression levels for collagen-encoding genes, and, therefore, contrubite to some collagen-associated pathologies. In this study, we demonstrate regulatory effects of USF1 on expression of genes encoding fibrillar collagen types I, II, and III in osteoblastic Saos-2 and MG-63 cells. An ectopic expression of the human USF1 led to a decrease in both mRNA and protein expression levels of the collagen-encoding genes mentioned above. ADAMTS-3 is a proteinase primarily responsible for the amino-terminal cleavage of type I and type II collagen precursors. The ADAMTS-3 promoter region contains potential binding sites for USF1. Here we show that an overexpression of USF1 lead to a decrease in ADAMTS-3 mRNA and protein expression levels. In co-transfection studies, USF1 negatively regulated ADAMTS-3 promoter activity. Further, in EMSA studies, we showed that USF1 binds to the ADAMTS-3 promoter region. In conclusion, it seems that ADAMTS-3 and USF1 contribute to the regulation of collagen encoding genes in osteosarcoma.

Effects of Se, Cu and Se + vitamin E deficiency on the activities of CuZnSOD, GSH-Px, CAT and LPO levels in chicken erythrocytes.

Antioxidant enzymes and vitamins provide a defence against the damage of cells by reactive oxygen species in living systems. The effect of Cu, Se and vitamin E deficiencies on the antioxidant enzyme activities and lipid peroxide levels of chicken erythrocytes were investigated during 6 weeks of a depletion diet. CuZnSOD activity and the plasma Cu level of the Cu-deficient group which was fed a diet containing 0.2 mg Cu x kg(-1) were reduced to 62 and 71% respectively. GSH-Px activity of the Se-deficient group was decreased by 46% but by 21% in the Cu-deficient group. CAT activity values of Se- and Cu-deficient groups were increased by 28 and 10% respectively. The maximum increase of LPO levels in erythrocyte membranes was observed as 32% for the Se+E-deficient group. The LPO level of the Cu-deficient group which had decreased CuZnSOD and GSH-Px activity, was also observed to be significantly increased when compared with the controls (p < 0.05).

Purification and characterization of catalase from chard (Beta vulgaris var. cicla).

Catalase is a major primary antioxidant defence component that primarily catalyses the decomposition of H(2) O(2) to H(2) O. Here we report the purification and characterization of catalase from chard (Beta vulgaris var. cicla). Following a procedure that involved chloroform treatment, ammonium sulfate precipitation and three chromatographic steps (CM-cellulose, Sephadex G-25, and Sephadex G-200), catalase was purified about 250-fold to a final specific activity of 56947 U/mg of protein. The molecular weight of the purified catalase and its subunit were determined to be 235 000 and 58 500 daltons, indicating that the chard catalase is a tetramer. The absorption spectra showed a soret peak at 406 nm, and there was slightly reduction by dithionite. The ratio of absorption at 406 and 275 nanometers was 1.5, the value being similar to that obtained for catalase from other plant sources. In the catalytic reaction, the apparent Km value for chard catalase was 50 mM. The purified protein has a broad pH optimum for catalase activity between 6.0 and 8.0. The enzyme had an optimum reaction temperature at 30 degrees C. Heme catalase inhibitors, such as azide and cyanide, inhibited the enzyme activity markedly and the enzyme was also inactivated by ?-mercaptoethanol, dithiothreitol and iodoacetamide.

Effects of antioxidant vitamins A, C, E and trace elements Cu, Se on CuZn SOD, GSH-Px, CAT and LPO levels in chicken erythrocytes.

The biologically damaging effects of reactive oxygen species are controlled in vivo by a wide spectrum of antioxidant defence mechanisms. Dietary constituents of antioxidant vitamins and trace elements may play an important role in protecting against oxidant damage. The effects of supplementation of vitamins A, C, E and trace elements Cu and Se on the activities of antioxidant enzymes and lipid peroxide levels in chicken erythrocytes were investigated depend on the time. CuZnSOD activity and plasma Cu levels in the Cu group were increased by 39 and 37 per cent respectively. CuZnSOD activity in vitamin C groups was also increased by 20 per cent. The GSH-Px activity in Se, Se+E and Se+Cu groups was raised by 35, 46 and 69 per cent respectively. Also, the GSH-Px activity in the vitamin C group was increased by 33 per cent. Catalase activity in all of these groups was not significantly different when compared with controls (p<0.01). The maximum decrease in LPO levels of 42 per cent was obtained for the Se+E group.