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Jiang Z Arnér ES Mu Y Johansson L Shi J Zhao S Liu S Wang R Zhang T Yan G Liu J Shen J Luo G 《Biochemical and biophysical research communications》2004,321(1):94-101
Evolution of a probable 'glutathione-binding ancestor' resulting in a common thioredoxin-fold for glutathione S-transferases and glutathione peroxidases may possibly suggest that a glutathione S-transferase could be engineered into a selenium-containing glutathione S-transferase (seleno-GST), having glutathione peroxidase (GPX) activity. Here, we addressed this question by production of such protein. In order to obtain a recombinant seleno-GST produced in Escherichia coli, we introduced a variant bacterial-type selenocysteine insertion sequence (SECIS) element which afforded substitution with selenocysteine for the catalytic Tyr residue in the active site of GST from Schistosoma japonica. Utilizing coexpression with the bacterial selA, selB, and selC genes (encoding selenocysteine synthase, SelB, and tRNA(Sec), respectively) the yield of recombinant seleno-GST was about 2.9 mg/L bacterial culture, concomitant with formation of approximately 85% truncation product as a result of termination of translation at the selenocysteine-encoding UGA codon. The mutations inferred as a result of the introduction of a SECIS element did not affect the glutathione-binding capacity (Km = 53 microM for glutathione as compared to 63 microM for the wild-type enzyme) nor the GST activity (kcat = 14.3 s(-1) vs. 16.6 s(-1)), provided that the catalytic Tyr residue was intact. When this residue was changed to selenocysteine, however, the resulting seleno-GST lost the GST activity. It also failed to display any novel GPX activity towards three standard peroxide substrates (hydrogen peroxide, butyl hydroperoxide or cumene hydroperoxide). These results show that recombinant selenoproteins with internal selenocysteine residues may be heterologously produced in E. coli at sufficient amounts for purification. We also conclude that introduction of a selenocysteine residue into the catalytic site of a glutathione S-transferase is not sufficient to induce GPX activity in spite of a maintained glutathione-binding capacity. 相似文献
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Yuanyuan Li Yuanyuan Zhang Yanhui Gao Wei Zhang Xiaohui Cui Junqiu Liu Yudan Wei 《Biological trace element research》2018,181(2):234-241
To further characterize the mechanisms underlying liver toxicity induced by arsenic, we examined in this study the effect of arsenic on thioredoxin (Trx) and the apoptotic signaling pathways in human liver HHL-5 cells. The cells were treated with 0, 2, 5, and 10 μM of sodium arsenite for 24 h, and the changes of Trx1 and thioredoxin reductase (TrxR1) as well as intracellular ROS and apoptosis were examined. A concentration-dependent increase in mRNA and protein levels of Trx1 and TrxR1 was observed in arsenic-treated cells. Intracellular ROS levels and apoptosis were also significantly increased in a concentration-dependent manner. In line with this, protein levels of Bax and cytochrome C were increased and Bcl-2 was decreased by arsenic treatments. Increases in caspase 3 activity were observed. These results indicate that Trx is involved in arsenic-induced liver cell injury, probably through the apoptotic signaling pathway. However, further studies are needed to elucidate on these findings. 相似文献
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Protection of epidermal cells against UVB injury by the antioxidant selenium-containing single-chain Fv catalytic antibody 总被引:2,自引:0,他引:2
Sun Y Mu Y Li W Lv S Jiang Z Zhang K Zheng K Lin F Yan G Luo G Liu J Shen J 《Archives of biochemistry and biophysics》2003,412(1):90-94
The antioxidant effect of selenium-containing single-chain Fv catalytic antibody (Se-scFv2F3), a new mimic of glutathione peroxidase, was confirmed using a model system in which cultured rat skin epidermal cells were injured by ultraviolet B (UVB). The cell damage was characterized in terms of lipid peroxidation of the cells, cell viability, and cell membrane integrity. The injury effects of UVB and protection effects of Se-scFv2F3 on the cells were studied using the model system. UVB can damage the cells severely. Upon precultivation of the cells with 0.4U/ml Se-scFv2F3, however, the damage was significantly reduced as shown by the increase in cell viability, the decrease in the malondialdehyde and hydrogen peroxide levels, and the normalization of lactate dehydrogenase activity. In addition, a novel finding that Se-scFv2F3 can stimulate cultured epidermal cells to proliferate under certain conditions was observed. 相似文献
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Zhiwu Han Daobing Chen Ka Zhang Honglie Song Kejun Wang Shichao Niu Junqiu Zhang Luquan Ren 《仿生工程学报(英文版)》2017,14(4)
The paper revealed the fine structure of the scorpion (Mesobuthus martensii) pectines and showed how the fine structure of the pecten influences odor flow.The first step of our investigation was to prove that scorpion pectines work as olfactory and this was done via experiments utilizing paraffin coverage.Subsequently,the location,morphology,section structure,and arrangement of the pectines were studied via stereomicroscopy and Scanning Electron Microscopy (SEM).The fine structure ofpecten comprises a comb-like structure with 24-30 knife-like teeth and thousands of micron bowl-like pecten sensilla in staggered arrangement on the surface of the tooth.Computational Fluid Dynamics (CFD) was applied to predict odor flow around the pecten via the relevant Reynolds numbers.The comb-like structure amplified the odor flow velocity similar to an amplifier,transporting the odor flow of increased velocity to the micron pecten sensilla,improving transport efficiency of the odor flow.The staggered arrangement of the pecten sensilla generated a vortex,improving contact duration between pecten sensilla and odorant molecules.Thus,the pecten finc structure was likely acting as an effective comb with non-smooth teeth for the transport and capture of odorant molecules. 相似文献
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2-位硒桥联β-环糊精的合成及催化性质 总被引:2,自引:0,他引:2
将β-环糊精(β-CD)2位羟基选择性磺酰化后,再用NaHSe处理使谷胱甘肽过氧化物酶(GPX)的催化基团-SeH引入β-CD的2位上,经空气氧化得到了GPX模拟物双硒桥联β-环糊精.利用元素分析、核磁共振、红外光谱对此模拟物进行了表征.X光电子能谱技术测定了模拟物中硒的价态和含量.测活结果表明模拟物的GPX活性是PZ51的7.5倍 相似文献
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Hu Zhao Junqiu Chen Jin Chen Xuhui Kong Hehuan Zhu Yongping Zhang Huiyue Dong Jie Wang Qun Ren Qinghua Wang Shushang Chen Zhen Deng Zhan Chen Qiang Cui Junqiong Zheng Jun Lu Shuiliang Wang Jianming Tan 《Journal of cellular physiology》2019,234(11):21060-21075
MicroRNAs have emerged as key regulators involved in a variety of biological processes. Previous studies have demonstrated that miR-192/215 participated in progression of Crohn's disease and colorectal cancer. However, their concrete relationships and regulation networks in diseases remain unclear. Here, we used bioinformatics methods to expound miR-192/215-5p macrocontrol regulatory networks shared by two diseases. For data mining and figure generation, several miRNA prediction tools, Human miRNA tissue atlas, FunRich, miRcancer, MalaCards, STRING, GEPIA, cBioPortal, GEO databases, Pathvisio, Graphpad Prism 6 software, etc . are extensively applied. miR-192/215-5p were specially distributed in colon tissues and enriched biological pathways were closely associated with human cancers. Emerging role of miR-192/215-5p and their common pathways in Crohn's disease and colorectal cancer was also analyzed. Based on results derived from multiple approaches, we identified the biological functions of miR-192/215-5p as a tumor suppressor and link Crohn's disease and colorectal cancer by targeting triglyceride synthesis and extracellular matrix remodeling pathways. 相似文献
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Junqiu Jiang Qingliang Zhao Liangliang Wei Kun Wang Duu-Jong Lee 《Bioresource technology》2011,102(1):272-277
Microbial fuel cell (MFC) could be an efficient sludge treatment unit in regard of rates and extents of total chemical oxygen demand (TCOD) removal, particularly when ultrasound was applied to pretreat the sludge. This study characterized the organic matter in sludge before and after MFC treatment, with or without ultrasound as a pretreatment stage. The 5-d MFC tests with electric load significantly enhanced TCOD removal rate from 11.3% to 19.2% for raw sludge and from 25% to 57% for sludge pretreated with >0.6 W ml?1 ultrasound, using conventional anaerobic digestion test (without electric load) as control. The aromatic proteins, soluble microbial byproduct-like fluorescent compounds and carboxylic components, aliphatic components (C–H related), hydrocarbon and carbohydrate materials were identified to be principally released by ultrasound pretreatment and the fuels in the present MFC study. 相似文献