不同凝乳酶对干酪成熟期间蛋白质降解的影响

本试验以西安常兴乳品厂当日生产鲜奶为原料,以进口的EZAL、MA0LL作发酵荆（由乳油连球菌和乳酸链球菌组成）,以微生物酶,小牛皱胃酶和胃蛋白酶,羔羊皱胃酶,木瓜蛋白酶。无花果蛋白酶作为凝乳酶生产硬质干酪,研究不同凝乳酶对干酪成熟期间蛋白质降解的影响。蛋白质降解测定结果表明,在干酪成熟过程中残留微生物凝乳酶和小牛皱胃酶对酪蛋白能力最强,天花果蛋白酶和木瓜蛋白酶最低,羔羊皱昌酶和猪胃蛋白酶居中。     

Impairment of liver regeneration by the histone deacetylase inhibitor valproic acid in mice

Background and objective: Liver regeneration is a complex process regulated by a group of genetic and epigenetic factors. A variety of genetic factors have been reported, whereas few investigations have focused on epigenetic regulation during liver regeneration. In the present study, valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, was used to investigate the effect of HDAC on liver regeneration. Methods: VPA was administered via intraperitoneal injection to 2/3 partially hepatectomized mice to detect hepatocyte proliferation during liver regeneration. The mice were sacrificed, and their liver tissues were harvested at sequential time points from 0 to 168 h after treatment. DNA synthesis was detected via a BrdU assay, and cell proliferation was tested using Ki-67. The expressions of cyclin D1, cyclin E, cyclin dependent kinase 2 (CDK2), and CDK4 were detected by Western blot analysis. Chromatin immunoprecipitation (ChIP) assay was used to examine the recruitment of HDACs to the target promoter regions and the expression of the target gene was detected by Western blot. Results: Immunohistochemical analysis showed that cells positive for BrdU and Ki-67 decreased, and the peak of BrdU was delayed in the VPA-administered mice. Consistently, cyclin D1 expression was also delayed. We identified B-myc as a target gene of HDACs by complementary DNA (cDNA) microarray. The expression of B-myc increased in the VPA-administered mice after hepatectomy (PH). The ChIP assay confirmed the presence of HDACs at the B-myc promoter. Conclusions: HDAC activities are essential for liver regeneration. Inhibiting HDAC activities delays liver regeneration and induces liver cell cycle arrest, thereby causing an anti-proliferative effect on liver regeneration.     

调节动物脂肪酸合成的核转录因子

脂肪酸的从头合成主要发生在肝脏和脂肪组织,肝脏脂肪酸的合成受到多种因素的调节,文章重点介绍调节脂肪酸合成的核转录因子:肝脏X受体固醇调节元件结合蛋白、碳水化合物反应元件结合蛋白。     

A new local ablation for unresectable primary liver tumor： effect of electrothermal and electrochemical therapy on rat liver

Background： Electrochemical therapy （ECT） has been used to treat unresectable hepatic tumor. In order to improve its efficacy, we combined ECT with hyperthermia induced by electrothermal needle （ETN） （ETECT）. The aim of this study is to investigate the destructive effect of ETECT on normal rat liver. Methods： Twenty rats were randomized into 4 treatment groups （n=5 in each group）： control, ECT alone, hyperthermia alone and ETECT. Following the treatment, sections of the livers were histologically examined by light microscopy and the destructive volumes were measured with micrometer. Results： We found that the destructive volumes in ETECT group were the largest （P〈0.01）. In ETECT group coagulative necrosis was found in both anode and cathode areas, around which transition zones existed. The transition zones can only be seen when coulomb was increased in ECT group. Conclusion： ETECT was demonstrated to enhance the destructive effect of ECT. This study provides theoretical and experimental basis for a new local ablative treatment for unresectable primary liver tumor.     

Proteomic analysis of differentially expressed proteins in mice with concanavalin A-induced hepatitis

Objective: To find new protein biomarkers for the detection and evaluation of liver injury and to analyze the relationship between such proteins and disease progression in concanavalin A (Con A)-induced hepatitis. Methods: Twenty-five mice were randomly divided into five groups: an untreated group, a control group injected with phosphate buffered saline (PBS), and groups with Con A-induced hepatitis evaluated at 1, 3 and 6 h. Two-dimensional gel elec-trophoresis (2-DE) and mass spectrometry (MS) were used to identify differences in protein expression among groups. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to verify the results. Results: In mice with Con A-induced hepatitis, expression levels of four proteins were increased: RIKEN, fructose bisphosphatase 1 (fbp1), ketohexokinase (khk), and Chain A of class pi glutathione S-transferase. Changes in fbp1 and khk were confirmed by qRT-PCR. Conclusion: Levels of two proteins, fbp1 and khk, are cleady up-regulated in mice with Con A-induced hepatitis.     

运动与自由基

本文采用文献综述法,阐述了自由基的类型、功能、自由基产生的机制以及抗氧化系统的种类等基本理论,特别随着自由基理论在竞技体育运动领域的运用,在运动过程中,不同形式的运动对体内自由基代谢及抗氧化酶活性的影响,成为运动医学关注的热点。通过4种不同形式的运动(急性运动、耐力运动、力竭运动和无氧运动)对自由基代谢及抗氧化酶活性的研究现状进行分析得出结论,并提出目前自由基研究中存在的不足。     

运动对抗氧化酶活性影响的研究进展

剧烈运动时自由基的大量生成与清除能力下降是导致运动性疲劳和运动性损伤的主要原因之一。抗氧化酶在保护机体免受自由基损伤中发挥着重要的作用。运动训练能增加抗氧化酶的活性，提高机体清除自由基的能力。不同抗氧化酶对不同运动训练的反应不同。本文通过文献查阅的方法，对国内外学者近年来关于运动训练对抗氧化酶影响的研究进行综述，为该领域的研究提供一定的理论指导。     

有氧运动协同抗氧化剂对老年小鼠肾脏线粒体质和量的影响

目的:研究小鼠衰老时肾脏线粒体形态、结构、功能及mtDNA的变化规律,观察有氧运动训练和抗氧化剂延缓肾脏老化的效果.方法:用电镜对线粒体观察计数,Clark氧电极法测定线粒体呼吸链CytC氧化酶及NADH脱氢酶活性,分光光度法测定抗氧化酶活性,聚合酶链反应检测mtDNA3866bp片段缺失率.结果:与5月龄小鼠比较,20月龄的老年小鼠肾脏线粒体数量减少、体积增大,线粒体呼吸控制率、ADP/O比值减小,呼吸链NADH脱氢酶、CytC氧化酶活性下降,mtDNA3866bp片段缺失率增加,而抗氧化酶活性却增大.结论:长期进行有氧运动和/或补充抗氧化剂可在一定程度上维持机体氧化与抗氧化的平衡,延缓mtDNA片段缺失率随增龄积累,预防线粒体老化,改善线粒体功能.     

Arsenic-Induced Hepatic Toxicity and Its Attenuation by Fruit Extract of Emblica officinalis (Amla) in Mice

Arsenic a metalloid and environmental contaminated has been found to be associated with public health problems in the affected areas. It is naturally occurred in groundwater and its accumulation in plant and animals leads to toxicity in several tissues most notably hepatic organ. Arsenic exposures (3 mg/kg body weight/day for 30 days) in mice exhibited increased arsenic and Zn levels in hepatocytes associated with enhanced oxidative stress in hepatocytes while there were no significantly changes were observed in Cu level. An increase in the lipid peroxidation and decrease in the levels of reduced glutathione and activity of superoxide dismutase, catalase, and glutathione peroxidase were observed in arsenic treated mice as compared to controls. Arsenic exposure in mice also caused a significant change in serum biomarkers in the SGOT, SGPT and creatinine as compared to the controls. There were no significant changes in the serum levels of total protein in these mice. Co-administration of arsenic and fruit extract of amla (500 mg/kg body weight/day for 30 days) caused a significant reduction of arsenic transference associated with significantly decreases hepatic arsenic levels and balanced the antioxidant enzyme and levels of serum hepatic enzymes like SGOT and SGPT. The results of the present study clearly demonstrate the antioxidant property of amla that could be responsible for its protective efficacy in arsenic induced hepatic toxicity.     

Enhancing polyphenol extraction from unripe apples by carbohydrate-hydrolyzing enzymes

The effects of process variables such as enzyme types, enzyme ratio, reaction temperature, pH, time, and ethanol concentration on the extraction of unripe apple polyphenol were investigated. The results indicated that Viscozyme L had the strongest effect on polyphenols extraction and was selected to study the polyphenol composition. The ratio of enzyme (Viscozyme L) to substrate (2 fungal beta-glucanase units (FBG)) at 0.02, reaction at pH 3.7,50 ℃ for 12 h, and ethanol concentration of 70% were chosen as the most favorable extraction condition. Total phenolic content (TPC), reducing sugar content (RSC), and extraction yield increased by about 3,1.5, and 2 times, respectively, compared with control. The contents of p-coumaric acid, ferulic acid, and caffeic acid increased to 8,4, and 32 times, respectively. The enzyme-aided polyphenol extraction process from unripe apples might be applied to food industry for enhancing bioactive compound production.