Role of deubiquitinating enzymes in DNA double-strand break repair     

Yunhui LI  Jian YUAN 《Journal of Zhejiang University. Science. B》2021,22(1):63-72

DNA is the hereditary material in humans and almost all other organisms. It is essential for maintaining accurate transmission of genetic information. In the life cycle, DNA replication, cell division, or genome damage, including that caused by endogenous and exogenous agents, may cause DNA aberrations. Of all forms of DNA damage, DNA double-strand breaks(DSBs) are the most serious. If the repair function is defective, DNA damage may cause gene mutation, genome instability, and cell chromosome loss, which in turn can even lead to tumorigenesis. DNA damage can be repaired through multiple mechanisms. Homologous recombination(HR) and non-homologous end joining(NHEJ) are the two main repair mechanisms for DNA DSBs. Increasing amounts of evidence reveal that protein modifications play an essential role in DNA damage repair.Protein deubiquitination is a vital post-translational modification which removes ubiquitin molecules or polyubiquitinated chains from substrates in order to reverse the ubiquitination reaction. This review discusses the role of deubiquitinating enzymes(DUBs) in repairing DNA DSBs. Exploring the molecular mechanisms of DUB regulation in DSB repair will provide new insights to combat human diseases and develop novel therapeutic approaches.  相似文献   

泌尿生殖系统感染状况及药敏分析     

廖晓林  张子雯 《中国科技信息》2006,(14):174-174,176

近年来，非淋菌性尿道炎（NGU）等的发病率呈上升趋势，而支原体是引起疾病的主要病原体之一。为了解支原体感染及耐药情况，我们对本地区支原体引起泌尿生殖道感染人群状况以及用9种抗生素进行了药敏分析，从而为临床治疗支原体感染的抗生素选择，泌尿生殖道感染患者的诊断，提供参考依据。  相似文献   

Effect of vitamin E on platelet enzymatic anti-oxidants in the patients of myocardial infarction     

Vivek K. Dwivedi  Mahesh Chandra  P. C. Misra  M. K. Misra 《Indian journal of clinical biochemistry : IJCB》2005,20(1):21-25

Effect of administration of 600 mg. vitamin E each day, for six days, was observed on activity of some of the anti-oxidant enzymes and levels of malondialdehyde (as an index of free radical mediated damage) in the platelets of patients reperfused after myocardial infarction. It has been found that vitamin E administration significantly lowers the level of malondialdehyde in the patients. Vitamin E administration increases the activities of anti oxidant enzymes (viz. superoxide dismutase, glutathione reductase and catalase) tested both in the patients and healthy controls. Vitamin E administration causes general stimulation of anti-oxidant enzyme activities both in healthy persons and the patients, however, lowering of lipid per-oxidation upon administration of vitamin E is specific for patients. These findings exhibit beneficial role of vitamin E administration in the management of the patients reperfused after myocardial infarction.  相似文献   

强电场电离放电对水稻幼苗生长生物学效应的试验性研究     

陈信  康珏  熊建平 《茂名学院学报》2011,21(6):20-24

为了研究强电场电离辐射对水稻种子酶活性的影响,在相同激励电压下,用不同时间辐射国稻6号水稻种子。发现用160V激励电压分别辐射10s、15s、20s、25s、30s、50s的试验组与对照组相比,淀粉酶、过氧化氢酶（CAT）和过氧化物酶（POD）的活性均有明显提高,淀粉酶辐射时间为25s效果最好,而CAT和POD辐射时间为25—30s时效果最佳。实验表明强电场电离辐射能促进水稻幼苗的生长发育和蛋白质合成,并降低活性氧对幼苗的损害。  相似文献   

Evaluation of the radioprotective effect of turmeric extract and vitamin E in mice exposed to therapeutic dose of radioiodine     

Uma S. Bhartiya  Yogita S. Raut  Lebana J. Joseph  Rohini W. Hawaldar  Badanidiyoor S. Rao 《Indian journal of clinical biochemistry : IJCB》2008,23(4):382-386

The aim of this study was to evaluate the radioprotective effect of turmeric extract (40 mg/kg body weight) and vitamin E (α- tocopherol acetate, 400 IU/kg body weight) supplementation on lipid peroxidation, reduced glutathione and antioxidant defense enzymes in various organs like liver, kidney and salivary glands at 24 h in adult Swiss mice. ¹³¹Iodine exposure significantly increased lipid peroxidation in kidney and salivary glands in comparison to control animals. Pre supplementation with turmeric extract for 15 days showed significant lowering of lipid peroxidation in kidney. On the other hand vitamin E pre supplementation showed marked reduction in lipid peroxidation in salivary glands. Reduced glutathione levels decreased significantly in liver after radiation exposure. However, pre supplementation with turmeric extract and vitamin E did not improve glutathione levels in liver. In conclusion, we have observed differential radioprotective effect of turmeric extract and vitamin E in kidney and salivary glands. However, Vitamin E seems to offer better radioprotection for salivary glands which is known to be the major site of cellular destruction after radioiodine therapy in patients.  相似文献   

烤烟种子萌发活动中有关酶及物质动态研究     

柴家荣  管仕军  刘敬业 《昆明师范高等专科学校学报》2009,31(3):16-19

以K326品种为材料,探索烤烟种子萌发活动中有关酶活性及相关物质的变化动态,结果表明：呼吸强度、淀粉酶与可溶性总糖和还原糖,蛋白酶与总游离氨基酸,脂肪酶与脂肪酸,以及过氧化物酶（POD）、多酚氧化酶（PPO）、可溶性蛋白质、脯氨酸（pro）、丙二醛（MDA）等的活性或含量都随种子萌发进程呈上升趋势,虽然其间有所起伏,但高峰期大都在第84～168h之间,仅POD、总游离氨基酸与MDA含量在萌发中期才开始明显上升,直到萌发结束时达高峰期．淀粉酶、蛋白酶、脂肪酶活性与各自催化水解的产物含量相关性显著,粗脂肪含量随萌发进程而下降,与脂肪酸含量呈极显著负相关．萌发集中在46～68h,发芽势96％,同步指数0．94．萌发动态符合Logistic生长曲线方程．  相似文献   

Extracellular expression in Bacillus subtilis of a thermostable Geobacillus stearothermophilus lipase     

《Electronic Journal of Biotechnology》2021

BackgroundThe extracellular expression of enzymes in a secretion host such as Bacillus subtilis is a useful strategy in reducing the cost of downstream processing of industrial enzymes. Here, we present the first report of the successful extracellular expression in Bacillus subtilis WB800 of Geobacillus stearothermophilus lipase (T1.2RQ), a novel industriallydesirable thermostable lipolytic enzyme which has an excellent hydrolytic and transesterification activity. Signal peptides of α-amylase, extracellular protease, and lipase A, as well as two different promoters, were used in the secretion and expression of lipase T1.2RQ.ResultsLipase activity assay using p-nitrophenyl laurate showed that all three signal peptides directed the secretion of lipase T1.2RQ into the extracellular medium. The signal peptide of lipase A, resulted in the highest extracellular yield of 5.6 U/ml, which corresponds to a 6-fold increase over the parent Bacillus subtilis WB800 strain. SDS-PAGE and zymogram analysis confirmed that lipase T1.2RQ was correctly processed and secreted in its original size of 44 kDa. A comparison of the expression levels of lipase T1.2RQ in rich medium and minimal media showed that the enzyme was better expressed in rich media, with up to an 8-fold higher yield over minimal media. An attempt to further increase the lipase expression level by promoter optimization showed that, contrary to expectation, the optimized promoter exhibited similar expression levels as the original one, suggesting the need for the optimization of downstream factors.ConclusionsThe successful extracellular secretion of lipase T1.2RQ in Bacillus subtilis represents a remarkable feat in the industrial-scale production of this enzyme.How to cite: Ridwan E, Suwanto A, Thenawidjaja M. Extracellular expression in Bacillus subtilis of a thermostable Geobacillus stearothermophilus lipase. Electron J Biotechnol 2021;53. https://doi.org/10.1016/j.ejbt.2021.07.003  相似文献   

昆虫壳聚糖对运动训练大鼠肝脏抗氧化酶系与SOD基因表达的影响     

高颖晖  周万红  曹军  王敦 《体育科学》2011,31(5):75-78

目的:报道了补充虫源壳聚糖对大鼠肝脏抗氧化酶系和SOD基因表达影响的研究结果。方法:对大负荷游泳训练大鼠补充剂量分别为各组平均体重的0.5 g/kg、1.0 g/kg和2.0 g/kg的虫源壳聚糖,在8周大负荷训练结束后测定肝脏抗氧化酶系的活性,并分析不同处理组动物肝脏SOD基因表达水平差异。结果:补充虫源壳聚糖能够显著提高抗氧化酶系活性,虫源壳聚糖0.5 g/kg补充组与单纯大负荷运动组相比,SOD、CAT和GSH-Px酶活性显著升高(P<0.05);虫源壳聚糖1.0 g/kg和2.0 g/kg补充组与单纯大负荷运动组相比:SOD、CAT和GSH-Px酶活性升高极为显著(P<0.01)。MDA含量在不同水平虫源壳聚糖补充组均显著低于单纯大负荷运动组(P<0.01)。对SOD基因表达分析结果显示,SOD酶活性的升高与其基因表达水平提高呈正相关。结论:补充虫源壳聚糖有助于提高训练大鼠的运动肝脏抗氧化酶系活性,活性的提高与相关编码基因的表达水平提高有关。  相似文献   

不同运动强度对肾上腺原癌基因C-fos蛋白表达的作用   总被引：9，自引：0，他引：9  

郭林  曹建民  田敏  徐晓阳  王琳  周铁民 《体育学刊》2002,9(3):33-34,37

通过观察在 3种不同运动强度下 ,大鼠肾上腺原癌基因C -fos蛋白表达的变化、尿总蛋白 (TP)排泄率的变化和相互关系 ,研究运动强度对肾上腺C -fos蛋白表达的影响 ,以及C -fos蛋白表达的变化在运动性疲劳、恢复及机能评定中的意义。结果表明 ,运动强度越大 ,肾上腺C -fos蛋白表达增加也大 ,且运动后恢复期恢复时间越长 ,肾上腺C -fos蛋白表达量越大。研究中第 4次C -fos表达测定都比第一次测定显著升高 (P <0 .0 5 )。在尿TP排泄率早已恢复的情况下 ,代表肾上腺结构、机能状态的C -fos表达却持续升高 ,表明利用肾上腺C -fos蛋白表达来进行运动性疲劳、恢复的判断及机能评定时 ,应注意肾上腺C -fos蛋白表达的时间特性。  相似文献   

Influence of dietary conjugated linoleic acid on growth, fatty acid composition and hepatic lipogenesis in large yellow croaker (Pseudosciaena crocea R.)     

Zhao ZY  Wu TX  Tang HG  Zhang JZ 《Journal of Zhejiang University. Science. B》2008,9(9):691-700

We examined the effects of conjugated linoleic acid (CLA) on growth, fatty acid composition and enzyme activity of fatty acid oxidation in the liver of large yellow croaker. We divided 1600 fish (average initial weight 150 g) into 4 groups and reared them in 8 cages. Four dietary treatments were formulated to contain 0%, 1%, 2% and 4% (w/w) CLA, respectively. The fish were fed for 10 weeks ad libitum twice daily. We found that the dietary CLA had no effect on growth, biometric parameters and whole body proximate (P>0.05), but showed some significant effects on the fatty acid composition in both muscle and the liver.The activities oflipogenic enzymes were slightly depressed in fish fed with increasing levels of CLA when compared with control (P>0.05). Dietary CLA supplementation had no effects on liver lipid content, but significantly increased the contents of saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) (P＜0.05) and decreased monounsaturated fatty acid (MUFA) content in both muscle and the liver. Dietary CLA inclusion resulted in significant increases of the biologically active cis-9, trans-11 and trans-10, cis-12 isomers in both tissues (P＜0.05). The total accumulation of CLA was higher in the liver (3.83%, w/w) than in muscle (3.77%, w/w) when fed with 4% (w/w) CLA. This study demonstrates that large yellow croakers are capable of absorbing and depositing CLA and long-chain n-3 PUFA in the liver and muscle, showing that this species fed with CLA could be an important human food source for these healthful fatty acids.  相似文献