Pengaruh Paparan Hipoksia terhadap Aktivitas Antioksidan Katalase dan Kadar Malondialdehid (MDA) pada Jaringan Hati Tikus

content in the tissue. Hypoxia can make the formation of free radicals or reactive oxygen species (ROS) which reactive to cell membrane. Body will avoid free radicals by producing antioxidant, such as catalase enzyme. The reaction between ROS and cell membrane will form malondialdehyde (MDA). Liver is the main location of catalase. This research was aimed to know the influence of hypoxia exposure toward catalase antioxidant activity and MDA content in the rat liver tissue. This research used experiment method with fully randomized design. Based on one way Anova test (p≤0.01), it was shown that there had no average difference on catalase activity and MDA content toward length hypoxia exposure. The conclusion of this research was no influence of hypoxia exposure toward catalase activity and MDA content in rat liver tissue. Key words: catalase antioxidant activity, hypoxia, malondialdehyde (MDA) content,rat liver tissue

Homology among bacterial catalase genes

Catalase activities in crude extracts of exponential and stationary phase cultures of various bacteria were visualized following gel electrophoresis for comparison with the enzymes from Escherichia coli. Citrobacter freundii, Edwardsiella tarda, Enterobacter aerogenes, Klebsiella pneumoniae, and Salmonella typhimurium exhibited patterns of catalase activity similar to E. coli, including bifunctional HPI-like bands and a monofunctional HPII-like band. Proteus mirabilis, Erwinia carotovora, and Serratia marcescens contained a single band of monofunctional catalase with a mobility intermediate between the HPI-like and HPII-like bands. The cloned genes for catalases HPI (katG) and HPII (katE) from E. coli were used as probes in Southern hybridization analyses for homologous sequences in genomic DNA of the same bacteria. katG was found to hybridize with fragments from C. freundii, Ent. aerogenes, Sal. typhimurium, and K. pneumoniae but not at all with Ed. tarda, P. mirabilis, S. marcesens, or Er. carotovora. katE hydridized with C. freundii and K. pneumoniae DNAs and not with the other bacterial DNAs. Key words: catalase genes, bacteria, homology.

Inheritance and expression of tissue-specific catalase activity during development and aging in mice

The catalase activity in the liver, kidney, lung, and blood hemolysate was measured in newborn, 21-, 70-, 175-, and >400-day-old mice from the strains BALB/c, Csb, C3H/HeSnJ, C3H/S, C57BL/6J, SW, and 129/ReJ. Catalase activity was found to be highest in the liver (~0.33 U/mg protein) followed by the kidney (~0.13 U/mg protein), lung (~0.05 U/mg protein), and blood hemolysate (~0.03 U/mg protein). ANOVA analysis indicated significant differences in enzyme activity among strains and age groups studied. The developmental profiles of enzyme activity were tissue and strain specific. Catalase activity in the blood, for example, was generally higher at birth and at old age, whereas the kidney catalase activity was low at birth and increased substantially with age. Strains could be classified as normal (129/ReJ, BALB/c, C3H/HeSnJ, C3H/S), hypocatalasemic (C57BL/6J, SW), and acatalasemic (Csb) with respect to enzyme activity and it was on this basis that the inheritance of the catalase phenotype was studied using appropriate crosses. The enzyme activity level in each tissue appears to be governed by a unique set of genetic regulators/modifiers that interact with a single structural gene (Cs) or its product to produce the catalase phenotype. Some of these (e.g., Ce-1 and Ce-2) have been previously described but based on the results of various crosses reported here, more must exist that remain still uncharacterized at the molecular level. Models proposed for the inheritance of the catalase phenotype vary in complexity from single allelic differences between strains (e.g., BALB/c × Csb; blood) to a system of multiple interacting genetic determinants (e.g., BALB/c × Csb; liver) each having dominant (e.g., C57BL/6J over BALB/c; liver) and recessive components (e.g., gene(s) conferring the acatalasemic phenotype in BALB/c × Csb; blood and kidney). Such results are important and offer an interesting model to further characterize aspects of eukaryotic gene regulation. Key words: catalase, inbred mice, tissue specificity, developmental profile, inheritance.