Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have conducted studies to obtain practical knowledge regarding the stability, digestion, and analytical determination of the content of 8-hydroxy-2-deoxy-guanosine (8-OHdG) in oxidatively damaged DNA. Utilizing H2O2 plus uv light to form oxidatively damaged DNA, we found that storage of the DNA at -20 degrees C at alkaline pH caused a significant loss of 8-OHdG, whereas storage at -20 degrees C at neutral or acidic pH prevented loss of 8-OHdG. The 8-OHdG within DNA is stable at 100 degrees C for at least 15 min. Formation of 8-OHdG within DNA using uv light and H2O2 as a hydroxyl free radical-generating system yields the highest amounts when low levels of phosphate buffer are used; but the use of Tris or citrate buffers causes a lower yield of 8-OHdG because these buffers act as scavengers for the hydroxyl free radicals. Independent assessment of hydroxyl free radical flux by the use of salicylate trapping allows assessment of competitive radical reactions. Ethanol washing of plastic microfuge tubes prior to DNA enzymatic digestion improved the yield of 8-OHdG and reduced the variability between samples. Digestion of the oxidatively damaged DNA by the use of a method involving DNase I, endonuclease, phosphodiesterase, and alkaline phosphatase produced the highest yield of 8-OHdG.
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PMID:Conditions influencing yield and analysis of 8-hydroxy-2'-deoxyguanosine in oxidatively damaged DNA. 222 56

In the current study, the role of endonuclease activity in calcium ionophore A23187-induced gastric mucosal cellular disruption was examined using rabbit gastric mucosal cells. Cell integrity was assessed using trypan blue dye exclusion and Alamar blue dye absorbance. Ionophore A23187 (1.6-25 microM) induced a concentration-dependent decrease in dye exclusion and cell metabolism in cells suspended in a medium containing Ca2+ (2 mM), while no such effect was observed in cells incubated in the absence of extracellular Ca2+. Cells that were pretreated with the endonuclease inhibitors aurintricarboxylic acid (ATCA; 0.2 or 0.5 mM or Zn2+; 0.01 and 0.1 mM) exhibited significant reduction in the total extent of cell injury when incubated with A23187 in the presence of Ca2+. DNA fragmentation as assessed by measurement of [3H]thymidine liberation or gel electrophoresis was increased in response to ionophore A23187 (12.5 or 25 microM) treatment. A minimal degree of fragmentation was observed when cells were suspended in a Ca(2+)-free medium or incubated in the presence of ATCA or Zn2+. Addition of ethanol (8% w/v) induced a significant increase in cell injury, which was not affected by either removal of extracellular Ca2+ or ATCA pretreatment. Furthermore, treatment with the antioxidants catalase (50 micrograms/ml) or 2',2'-dipyridyl (2 mM) reduced ionophore-induced cell injury but did not reduce the extent of DNA fragmentation. These data suggest that sustained increases in intracellular Ca2+ result in increased endonuclease activity in gastric mucosal cells, leading to extensive DNA lysis and cell damage. Ethanol-induced cell damage does not involve Ca2+ influx and therefore is not mediated by endonuclease activation. Furthermore, sustained increases in cellular Ca2+ may also mediate their effects via formation of reactive oxygen metabolites, but this mechanism of cell damage does not appear to involve DNA fragmentation.
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PMID:Role of endonuclease activity and DNA fragmentation in Ca2+ ionophore A23187-mediated injury to rabbit isolated gastric mucosal cells. 865 49

Ethanol-inducible cytochrome P4502E1 is the main pathway in the non-alcohol dehydrogenase oxidation of ethanol. Its coding gene, CYP2E1, is polymorphic at the Rsa I restriction site in the 5'-flanking region. The mutant genotype c2c2 has a higher transcriptional activity than the genotype c1c1 or c1c2. Heavy drinkers carrying the c2 allele might be at a higher risk of alcoholic cirrhosis since they might synthesize greater amounts of acetaldehyde, the compound believed responsible for hepatotoxicity of ethanol. With the aim of establishing if the c2 allele increases the risk of cirrhosis in heavy drinkers, we studied 58 (6 female) chronic heavy drinkers with liver cirrhosis and 137 healthy normal controls of the same ethnic (white Spaniards) origin. After extraction of DNA from white blood cells, alleles c1 and c2 of CYP2E1 were identified by restriction fragment length polymorphism (RFLP) with endonuclease Rsa I. Fifty-six patients and 130 controls were classified as homozygous c1c1 and two and seven, respectively, as heterozygous c1c2. No homozygous c2c2 were detected. The c2 allele frequencies were 0.017 in patients and 0.026 in controls (non-significant differences). We conclude that the Rsa I RFLP polymorphism is probably not related to the risk of cirrhosis in Spanish heavy drinkers.
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PMID:Rsa I polymorphism at the cytochrome P4502E1 locus is not related to the risk of alcohol-related severe liver disease. 902 17

The heat and ethanol stress response of Bacillus licheniformis DSM13 was analyzed at the transcriptional and/or translational level. During heat shock, regulons known to be heat-induced in Bacillus subtilis 168 are upregulated in B. licheniformis, such as the HrcA, SigB, CtsR, and CssRS regulon. Upregulation of the SigY regulon and of genes controlled by other extracytoplasmic function (ECF) sigma factors indicates a cell-wall stress triggered by the heat shock. Furthermore, tryptophan synthesis enzymes were upregulated in heat stressed cells as well as regulons involved in usage of alternative carbon and nitrogen sources. Ethanol stress led to an induction of the SigB, HrcA, and CtsR regulons. As indicated by the upregulation of a SigM-dependent protein, ethanol also triggered a cell wall stress. To characterize the SigB regulon of B. licheniformis, we analyzed the heat stress response of a sigB mutant. It is shown that the B. licheniformis SigB regulon comprises additional genes, some of which do not exist in B. subtilis, such as BLi03885, encoding a hypothetical protein, the Na/solute symporter gene BLi02212, the arginase homolog-encoding gene BLi00198 and mcrA, encoding a protein with endonuclease activity.
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PMID:The response of Bacillus licheniformis to heat and ethanol stress and the role of the SigB regulon. 2359 18