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Antioxidant Protein (antioxidant + protein)
Selected AbstractsProteomic identification of peroxiredoxin 6 for host defence against Opisthorchis viverrini infectionPARASITE IMMUNOLOGY, Issue 5 2010J. KHOONTAWAD Summary Opisthorchis viverrini infection causes opisthorchiasis and is a risk factor for cholangiocarcinoma via chronic inflammation. To investigate the mechanism of O. viverrini -induced liver disease, we applied a proteomic approach to examine alterations in hepatic protein levels in O. viverrini -infected hamsters. Two-dimensional gel electrophoresis (2DE) revealed that O. viverrini infection induced upregulation (1·5- to 4·3-fold) of 25 proteins and downregulation (1·5 to 2·5-fold) of 24 proteins compared with uninfected animals. Expression of proteins related to stress response, DNA replication and repair, and cell structure was significantly increased, whereas that of proteins associated with normal liver function, such as metabolism, blood volume maintenance and fatty acid cycle was decreased. Among the upregulated proteins, a 2·7-fold increase in peroxiredoxin 6 (Prdx6), an antioxidant protein, was confirmed by 2DE and immunoblot analysis, Western blot and quantitative PCR. Immunohistochemical analysis showed that Prdx6 expression was observed mainly in the cytoplasm of inflammatory cells. These results suggest that Prdx6 is important for host defence against O. viverrini infection. This study provides basic information for Prdx6 as a potential biomarker and therapeutic target for opisthorchiasis. [source] Susceptibility to oxidative stress: proteomic analysis of bronchoalveolar lavage from ozone-sensitive and ozone-resistant strains of micePROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 5 2003Ruddy Wattiez Abstract Previous studies have shown that the pulmonary response to ozone (O3) varies greatly among strains of mice, but the factor(s) and the mechanism(s) that are responsible for this differential susceptibility have not yet been clearly identified. The present study explores the molecular bases for this differential O3 susceptibility by studying the expression of proteins associated to the epithelial lining fluid (ELF) from two strains of mice, C57BL/6J and the C3H/HeJ, respectively described as O3 -sensitive and O3 -resistant. The ELF proteins of these two strains were displayed by two-dimensional gel electrophoresis (2-DE) of bronchoalveolar lavage fluids (BALFs) and the protein patterns obtained with BALF samples of both strains were compared. Two major differences were observed between the BALF 2-DE protein maps obtained from C57BL/6J and C3H/HeJ strains. First, two isoforms of the antioxidant protein 2 (AOP2) were detected in a strain-dependent manner: C3J/HeJ possesses only AOP2a (isoelectric point 5.7) and C57BL/6J exhibits only AOP2b (isoelectric point 6.0). Second, the levels of anti-inflammatory and immunosuppressive Clara cell protein-16 (CC16) were 1.3 times higher in the BALF from resistant C3H/HeJ than from sensitive C57BL/6 mice. Moreover, two 6 kDa isoforms of CC16 with isoelectric points of 4.9 (CC16a) and 5.2 (CC16b) are detected in both strains. Interestingly, the C57BL/6J strain had a twice decreased level of the acidic isoform of CC16 compared to C3H/HeJ. Our results suggest that AOP2 and CC16 might participate in the protection of the pulmonary tract to O3 -induced lung injury. The possible differential contribution of specific protein isoforms in the differential susceptibility to oxidative stress is discussed. [source] Protein expression profiling of glutathione S -transferase pi null mice as a strategy to identify potential markers of resistance to paracetamol-induced toxicity in the liverPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 2 2003Neil R. Kitteringham Abstract GST pi (GSTP) is a member of the glutathione S -transferase (EC 2.5.1.18; GST) family of enzymes that catalyse the conjugation of electrophilic species with reduced glutathione and thus play an important role in the detoxification of electrophilic metabolites. Deletion of GSTP in mice has previously been shown to lead to enhanced susceptibility to chemical-induced skin carcinoma, consistent with its known metabolic functions. A decreased susceptibility to paracetamol hepatotoxicity has also been observed, which has not been fully explained. One possibility is that deletion of the GSTP gene locus results in compensatory changes in other proteins involved in defence against chemical stress. We have therefore used complementary protein expression profiling techniques to perform a systematic comparison of the protein expression profiles of livers from GSTP null and wild-type mice. Analysis of liver proteins by two-dimensional electrophoresis confirmed the absence of GSTP in null mice whereas GSTP represented 3,5% of soluble protein in livers from wild-type animals. There was a high degree of quantitative and qualitative similarity in other liver proteins between GSTP null and wild-type mice. There was no evidence that the absence of GSTP in null animals resulted in enhanced expression of other GST isoforms in the null mice (GST alpha, 1.48%, GST mu, 1.68% of resolved proteins) compared with the wild-type animals (GST alpha, 1.50%, GST mu, 1.40%). In contrast, some members of the thiol specific antioxidant family of proteins, notably antioxidant protein 2 and thioredoxin peroxidases, were expressed at a higher level in the GSTP null mouse livers. These changes presumably reflect the recently described role of GSTP in cell signalling and may underlie the protection against paracetamol toxicity seen in these animals. [source] Molecular cloning and characterization of ATX1 cDNA from the mole cricket, Gryllotalpa orientalisARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 4 2006Iksoo Kim Abstract To search for an insect homologue of antioxidant protein 1 (ATX1), a mole cricket, Gryllotalpa orientalis, cDNA library was screened and a cDNA clone, which encodes a 73 amino acid polypeptide with a predicted molecular mass of 8.0 kDa and pI of 5.68, was isolated. The G. orientalis ATX1 (GoATX1) cDNA features both a MTCXXC copper-binding site in the N-terminus and a KTGK lysine-rich region in the C-terminus. The deduced amino acid sequence of the GoATX1 cDNA showed 63% identity to Drosophila melanogaster ATX1 and 55% to Ixodes pacificus ATX1. Northern blot analysis revealed the presence of GoATX1 transcripts in midgut, fat body, and epidermis. When H2O2 was injected into the body cavity of G. orientalis adult, GoATX1 mRNA expression was up-regulated in the fat body tissue. Fat body expression level of GoATX1 mRNA in the fat body was increased following exposure to low (4°C) and high (37°C) temperatures, suggesting that GoATX1 plays a protective role against oxidative stress caused by temperature shock. This is the first report about a functional role of insect ATX1 in antioxidant defense. Arch. Insect Biochem. Physiol. 61:231,238, 2006. © 2006 Wiley-Liss, Inc. [source] Oxidative mutagenicity of polar fractions from polycyclic aromatic hydrocarbon,contaminated soilsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2008Joanna Park Abstract Soils at hazardous waste sites contain complex mixtures of chemicals and often are difficult to characterize in terms of risk to human and ecological health. Over time, biogeochemical processes can decrease the apparent concentrations of pollutants but also can lead to accumulation of new products for which toxicity and behavior in the environment are largely unknown. A bioassay-directed fractionation technique was used to assess the contribution of redox-active bacterial metabolites to the toxicity of soil contaminated with polycyclic aromatic hydrocarbons (PAHs). A reverse mutation assay with Escherichia coli WP2 uvrA/pKM101 (IC188) and E. coli WP2 uvrA oxyR/pKM101 (IC203) was used to screen fractions for genotoxicity. Strain IC203 carries the ,oxyR30 mutation, which prevents the expression of antioxidant proteins in response to oxidative stress and increases its reversion by compounds that generate reactive oxygen species (ROS). Polar fractions of PAH-contaminated soil extracts were mutagenic to strain IC203 but not to strain IC188, suggesting the involvement of ROS in genotoxicity. Genotoxic potencies ranged from 300 to 1,700 revertants per milligram of fraction. Catalase was able to decrease IC203 reversion, implicating the involvement of hydrogen peroxide as a key ROS. Oxidized PAH compounds, including quinones, were identified in the mutagenic fractions but were not by themselves mutagenic. Deasphalted whole extracts and recombined fractions were not mutagenic, indicating that interactions between compounds in different fractions can mitigate genotoxicity. [source] Proteomic analysis of pulmonary sclerosing hemangiomaPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 17 2006Lian-Jin Jin Abstract Sclerosing hemangioma (SH) is a rare benign pulmonary tumor derived from the primitive respiratory epithelium. However, the pathogenesis of SH has not yet been clear. Surfactant protein, thyroid transcription factor-1, epithelial membrane antigen, cytokeratin, and vimentin have been identified in SH by immunohistochemistry and electron microscopy. To identify proteins specifically regulated in SH, 2-D PAGE was performed using SH and paired normal tissues. Ten selected differentially expressed protein spots were identified by PMF, MALDI-TOF-MS, and database searching. Apolipoprotein,A-1, antizyme inhibitor, heat shock 27-kDa protein,1, and antioxidant proteins, such as peroxiredoxin,II (Prx,II) and GST, were identified among the down-regulated proteins in SH. Western blot and immunohistochemistry confirmed reduced expressions of Prx,II and GST in SH versus normal lung tissue. This study is the first report on the reduced expressions of Prx,II and GST in SH. [source] Structures of two superoxide dismutases from Bacillus anthracis reveal a novel active centreACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2005Ian W. Boucher The BA4499 and BA5696 genes of Bacillus anthracis encode proteins homologous to manganese superoxide dismutase, suggesting that this organism has an expanded repertoire of antioxidant proteins. Differences in metal specificity and quaternary structure between the dismutases of prokaryotes and higher eukaryotes may be exploited in the development of therapeutic antibacterial compounds. Here, the crystal structure of two Mn superoxide dismutases from B. anthracis solved to high resolution are reported. Comparison of their structures reveals that a highly conserved residue near the active centre is substituted in one of the proteins and that this is a characteristic feature of superoxide dismutases from the B. cereus/B. anthracis/B. thuringiensis group of organisms. [source] | ||||||||||