[State of the liver antioxidant system and content of matrix metalloproteinase-2 of the large intestine under the effect of maleimide derivative in experimental colorectal carcinogenesis in rats].

The maleimide derivative--1-(4-Cl-benzyl)-3-Cl-4-(CF3-phenylamino)-1H-pyrrol-2.5-dione (MI-1) with cytostatic activity did not cause substantial changes of liver antioxidant system and level of matrix metalloproteinase-2 in intestinal mucosa after chronic treatment (for 20 weeks). MI-1 did not cause significant changes in the content of thiobarbituric-active products and plasma membrane protein carbonyl groups in the rat liver. However activities of superoxide dismutase, glutathione peroxidase, and content of reduced glutathione were decreased in both doses--0.027 and 2.7 mg/kg. The level of matrix metalloproteinase-2 in intestinal mucosa was decreased just in maximum dose--2.7 mg/kg. The contents of thiobarbituric-active products, protein carbonyl groups, reduced glutathione, matrix metalloproteinase-2, activities of glutathione peroxidase and glutathione-S-transferase in the liver cells have increased in 1.2-dimethylhydrazine-induced colon cancer in rats. The activities of enzymes of the first line of antioxidant defense--superoxide dismutase and catalase were decreased to 40%. The maleimide derivative prevents development of oxidation stress and partially reduce them to control level.

[Role of Cu, Zn- and Mn-containing superoxide dismutases during the yeast Saccharomyces cerevisiae growing on ethanol and glycerol].

Growth of the yeast Saccharomyces cerevisiae deficient as to superoxidedismutase (SOD) genes in the media containing ethanol or glycerol has been investigated. It was shown that the role of the two isoforms of SOD was different under conditions used in this study. The strain which has only mitochondrial Mn-SOD demonstrated higher velocity of culture growth on ethanol compared with the other strains investigated. In contrast to that, cytosolic Cu, Zn-SOD played more important role under growth on glycerol than Mn-SOD. The levels of carbonyl proteins in SOD-deficient strains grown on glycerol and in the cells of strain producing only Cu, Zn-SOD exposed to inhibitor diethyldithiocarbamate were investigated. The strains lacking Mn-SOD and Cu, Zn-SOD demonstrated virtually the same levels of carbonyl proteins. It is supposed that Cu, Zn-SOD can compensate Mn-SOD and vice versa. Nonlinear correlation between SOD activity and the level of carbonyl proteins was found that indicates to the uncertain role of SOD in protein oxidation.

[The role of catalases in protection of proteins against oxidation in Saccharomyces cerevisiae utilizing ethanol as a carbon source].

The content of protein carbonyls and thiobarbituric acid reactive substances (TBARS) in the wild and catalase-deficient strains of the yeast Saccharomyces cerevisiae grown in glucose and ethanol media are compared. The deficient strain cells reproduced 10.6-fold slower in ethanol-containing medium. Activity of glucose-6-phosphate dehydrogenase in YWT1 cells was 1.7-fold lower when yeast are grown in ethanol, and content of protein carbonyls was 4.7-fold higher, than when they are grown in the medium with glucose. At the same time, reproduction of the wild type cells in ethanol was 2.7-fold slower and carbonyl groups of protein content was 2-fold lower, than under cultivation in glucose. TBARS content in both strains was similar when they were grown in ethanol and in glucose. It has been supposed that catalases play a certain role in the protection of S. cerevisiae proteins against oxidative modification when they are grown on the media with glucose and ethanol.