哺乳动物α-羟基丁酸脱氢酶的测定及临床意义

α-羟基丁酸脱氢酶（HBDH）是心肌酶谱中的一种酶，在哺乳动物体内普遍存在，主要分布于心肌红细胞、白细胞及肾脏等。HBDH活性升高常见于急性心肌梗塞、骨骼肌损伤、急性肝炎、白血病及恶性肿瘤等。可用紫外动力学法、速率法、酶学比色法、连续检测等方法来测定HBDH的活性。LDH／HBDH比值可以帮助诊断肝病或心脏病。HBDH活性测定在临床诊断中有重要意义，在某些临床诊断中HBDH、CK、CK-MB需联合测定，但就心肌受损相关疾病而言，没必要同时检测。由于酶基因表达的多样性，基因表达调控上的差异性，产生了各种动物酶结构的多样性，进行HBDH的分子遗传研究非常必要。     

杏鲍菇菌柄中SOD活性研究

对不同温度、pH、水浴时间下杏鲍菇菌柄中SOD酶比活性及其保留率进行研究,结果表明,杏鲍菇菌柄具有较高的SOD活性,25℃下,比活性可达351.4U/mg prot,最适宜保存其活性的pH为7.80,杏鲍菇菌柄中的SOD热稳定性突出,即使在100℃下水浴15min后,其SOD酶活保留率仍然高达74.17%（以25℃时测定活性为100%）,具备优良的加工性能,但长时间的高温条件会使SOD酶活性的逐渐下降。     

大蒜素对肉鸡生产性能和消化酶活性的影响

135只1日龄AA鸡随机分成A、B、C3组,每组设3个重复,每个重复15只。A为空白对照组,饲喂基础日粮,B为抗生素组,在基础日粮中添加50mg／kg洛克沙生和750mg／kg10％金霉素,C为试验组,在基础日粮中添加160mg／kg25％大蒜素,以研究大蒜素对肉鸡生产性能和十二指肠消化酶活性的影响。试验结果表明,A、B、C3组肉鸡平均体重和平均日增重差异不显著（P〉0．05）,与A组相比,42日龄时C组料重比差异显著（P〈0．05）。在21日龄和42日龄时,C组淀粉酶活性较A组提高了122．87％（P〈0．01）和40．50％（P〈0．01）,脂肪酶活性较A组提高了89．98％（P〉0．05）和33．33％（P〉0．05）,总蛋白酶活性较A组提高了10．29％％（P〉0．05）和1．7％（／9〉0．05）。本结果提示在肉鸡饲料中添加大蒜素能够提高饲料效率和肠道淀粉酶活性。     

碱性蛋白酶高产菌株的筛选

实验采用土壤为样品,对样品进行分离,纯化,培养,筛选出了3株产酶能力较高的菌株,即R1、R2、R3。复筛确定了R1的产酶能力相对较高。通过相对酶活力的测定,确定了反应最佳温度为30℃,最佳pH为9。菌株在最适条件下产酶能力达246.8U/ml。     

Genotypic and environmental variation in barley limit dextrinase activity and its relation to malt quality

Variation in the limit dextrinase activity of barley malt, and the relationships between limit dextrinase activity and malt quality parameters were investigated using eight cultivars grown at seven diverse locations in China for two successive years. Limit dextrinase activity varied with genotype and location, with the levels ranging from 0.245 U/g to 0.980 U/g. The results showed that the variation in limit dextrinase activity was more attributable to the environment （location and year） than to the genotype. The response of limit dextrinase activity to the environment differed markedly among cultivars, and was reflected by large difference in coefficient of variation of cultivars across diverse locations. Regression analysis showed that limit dextrinase activity was negatively correlated with malt viscosity （r=-0.52, P〈0.01）, positively correlated with Kolbach index （r=0.38, P〈0.01） and malt extract （r=0.30, P〈0.05）, but had no significant correlation with malt protein content and diastatic power.     

Adapting the usage of enzyme unit to its definition

The enzyme unit U, by its definition, is the amount of enzyme that catalyses the transformation of one micromole of substrate per minute under standard assay conditions. However, in practical use, it is identical with micromole or microgram per minute, which deviates from the essence of the definition as a measure of amount of substance. Such usage appears in many publications that involve enzyme kinetics and conveys obscure signification. In this article, we solved the confusion by regarding the unit U as a measure of amount of enzyme having a specified catalytic activity just like the basic SI unit mole (symbol mol) defined as the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kg of carbon 12. We introduced the concept of unit rate, ru, which is defined as the rate of a reaction mediated by 1 U enzyme, in calculating the enzyme units in an amount of enzyme so as to avoid the inconsistence of the expression with the definition of enzyme unit. The method can also be applied to the case of katal, the recommended SI unit of enzyme activity.     

Kinetic analysis of γ-glutamyltransferase reaction process for measuring activity via an integration strategy at low concentrations of γ-glutamyl p-nitroaniline

At 0.12 mmol/L γ-glutamyl p-nitroaniline (GGPNA), an improved integrated method was developed for kinetic analysis of γ-glutamyltransferase (GGT) reaction process and the integration with the classical initial rate method to measure serum GGT. For the improved integrated method, an integrated rate equation, which used the predictor variable of reaction time and considered inhibitions by both GGPNA and products, was nonlinearly fit to GGT reaction processes. For the integration strategy, classical initial rates were estimated when GGPNA consumption percentages were below 50%; otherwise, maximal reaction rates of GGT were estimated by the improved integrated method and converted into initial rates according to the differential rate equation at 0.11 mmol/L GGPNA. The integration strategy was validated using optimized GGT kinetic parameters and 10-s intervals to record reaction curves within 8.0 min. By the integration strategy, there was a linear response from 0.9 to 32.0 U/L GGT, coefficients of variation were below 3.5% for GGT from 8.0 to 32.0 U/L (n=5), and GGT activities in clinical sera responded linearly to their classical initial rates at 2.00 mmol/L GGPNA with an expected slope. Therefore, the integration strategy was successful in measuring GGT at 0.12 mmol/L GGPNA.     

一株产生淀粉糖化酶的拟青霉

从土壤中分离筛选到一株降解生淀粉能力较强的菌株,通过固体发酵其生淀粉糖化酶活为2237U/g（按U/g麦麸计）,RDA值为15.25%。根据形态学特性初步鉴定该菌属于拟青霉属（Paecilomyces sp.）。其最适生长温度为30℃,最适生长起始pH5。其粗酶液24h水解生玉米淀粉的水解率为86.88%;对不同来源的生淀粉的水解能力不同,为玉米粉〉面粉〉米粉〉木薯粉〉甘薯淀粉;其最适作用pH为4,最适作用温度为70℃。     

Variation in β-amylase activity and thermostability in Tibetan annual wild and cultivated barley genotypes

β-Amylase activity (BAA) and thermostability (BAT) are important traits for malt quality. In this study, 138 Tibetan annual wild barley accessions and 20 cultivated genotypes differing in BAA were planted and analyzed in 2009 and 2012. Significant differences were detected among genotypes in BAA and BAT. The cultivated genotypes had a mean BAA of 1137.6 U/g and a range of from 602.1 to 1407.5 U/g, while the wild accessions had a mean of 1517.9 U/g and a range of from 829.7 to 2310.0 U/g. The cultivated genotypes had a mean relative residual β-amylase activity (RRBAA) of 61.6% and a range of from 22.2% to 82.3%, while the wild barleys had a mean of 57.8% and a range of from 21.9% to 96.1%. Moreover, there was a significant difference among genotypes in the response of RRBAA to the temperature and duration of heat treatment. The wild barleys had wider variation in BAA and BAT than cultivated genotypes.     

鸡传染性贫血病弱毒苗免疫对肝线粒体抗氧化酶活性的影响

观察鸡传染性贫血病弱毒苗多次免疫对肝线粒体中抗氧化酶活性的影响。方法：20只SPF鸡随机分为2组,每组10只,免疫组鸡用鸡传染性贫血弱毒苗免疫四次,每次间隔2W,对照组鸡用同剂量的生理盐水。最后一次免疫后10d取肝脏制备线粒体,利用测试盒测定肝线粒体中的GSH-PX活性、SOD活性和MDA含量。结果：对照组肝线粒体中GSH-Px活性、SOD活性和MDA含量分别为20．444±2．64U／mgprot、15．59±1．33U／mgprot和7．32＋1．89nmol／mL,免疫组肝线粒体中GSH-Px活性、SOD活性和MDA含量分别为24．85±3．53U／mgprot、24．284±4．17U／mgprot和5．264±1．24nmol／mL。与对照组相比,免疫组肝线粒体中GSH-PX活性显著提高（P〈0．05）,SOD活性极显著提高（P〈0．01）,MDA含量显著减低（P〈0．05）。结论：鸡传染性贫血病多次免疫可提高机体抗氧化能力。     

抗氮营养阻遏黄孢原毛平革菌pcR5305产酶条件优化

对选育的抗营养阻遏产酶黄孢原毛平革菌pc R5305菌株的产酶营养基质与环境条件进行了优化。实验结果表明pc R5305在37℃、初始p H4.5条件下,以酒石酸铵（富氮2.2g/L）,葡萄糖（20g/L）,Mn^2＋（0.2g/L）,Tween 80（1g/L）为主要成分的优质培养基中培养24h后添加5.2mmol/L苯甲醇,pc R5305的产酶活性最高。上述条件下,该菌接种后静置培养6 d,Li P活力可达到2013.59U/L,Mn P活力达到353.42U/L,分别提高了23.41%和27.97%。     

Preparation of Glutaraldehyde Cross-Linked Chitosan Beads Under Microwave Irradiation and Properties of Urease Immobilized onto the Beads

The glutaraldehyde cross-linked chitosan beads were prepared under microwave irradiation and urease was immobilized onto the beads. The activity and the yield of enzyme activity of the immobilized urease were 10.83 U/g carrier and 47.7%, respectively. The optimum conditions of immobilization were 1% of glutaraldehyde volume fraction, 10 mg/g of urease/beads weight ratio, 24 h of the processing time and pH 6.5 of the reaction medium for immobilization. The properties of the immobilized urease were investigated and compared with those of the free enzyme. The optimum pH values were 6.5 and 7.0 for the immobilized and free urease, respectively. The optimum temperature was 60℃ for the free urease, while it shifted to 65 ℃ for the immobilized enzyme. The Michaelis constant Kr, was 9.1 mmol/L for the immobilized and 12.5 mmol/L for the free urease. The immobilized urease retained 40% of its initial enzyme activity even after 10 repeated uses. The immobilized urease stored at 4 ℃ retained 46% of its initial activity even after 35 d.     

肢体缺血预处理对大鼠坏死心肌的保护作用

目的:研究肢体缺血预处理(LIP)对大鼠缺血再灌后心脏损伤的影响。方法:采用反复捆绑后肢造成缺血预适应的方法,观察其对心肌缺血再灌后梗死面积和形态学改变的影响,对心肌CK-MB和cTn-I的影响,以及对抗氧化物酶的影响。结果:与缺血再灌组比较,预处理能明显降低心肌梗死面积,减轻心肌细胞的损害,减少心肌酶的漏出并能提高SOD的活性。结论:LIP对心肌损伤具有保护作用。     

Expression of Drosophila melanogaster acetylcholinesterase (DmAChE) gene splice variants in Pichia pastoris and evaluation of its sensitivity to organophosphorus pesticides

Acetylcholinesterase(AChE) is a key enzyme used to detect organophosphorus pesticide residues by the enzyme inhibition method.An accidental discovery of a mutant strain with AChE activity was made in our laboratory during the process of AChE expression by Pichia pastoris.The pPIC9 K-Drosophila melanogaster acetylcholinesterase(DmAChE)-like expression vector was constructed by codon optimization of this mutant strain,which was transformed into P.pastoris GS115,and positive clones were selected on yeast peptone dextrose(YPD) plate with G418 at 4.0 mg/mL.The GS115-pPIC9 K-DmAChE-like strain was subjected to 0.5% methanol induction expression for 120 h,with a protein band at 4.3 kDa found by the tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) pattern of the fermentation supernatant.After preliminary purification by ammonium sulfate precipitation,the enzyme activity was detected to be 76.9 U/(mL·min).In addition,the pesticide sensitivity test proved that DmAChE-like is selective and sensitive to organophosphorus pesticides.     

种子劣变机制研究进展

种子劣变是种子内部一系列生理生化反应的结果.主要表现在:细胞膜完整性的丧失和脂质过氧化程度的加深,各种酶类活性的降低,呼吸协调的不断破坏,种子内蛋白质、脂肪等贮藏物质的变化以及赤霉素、脱落酸等激素含量的变化等方面.     

复合蛋白酶和谷氨酰胺转氨酶对潮式卤鸭的嫩化效果研究

以持水力、烹饪失水率及感官评分为指标,探讨复合蛋白酶（木瓜蛋白酶和菠萝蛋白酶）和谷氨酰胺转氨酶（TG）处理对鸭肉的嫩化效果,并通过L9（34）正交试验优化工艺条件.结果表明：复合蛋白酶和谷氨酰胺转氨酶液的酶活、处理温度、处理时间、pH值对鸭肉的持水力和烹饪失水率均有显著影响;复合蛋白酶的最佳嫩化条件为酶用量0.10 mg/mL（即木瓜蛋白酶用量90 U/mL和菠萝蛋白酶用量15 U/mL）,作用温度30℃,作用时间40 min,pH 7.2,此条件下的持水力可达91.25%;在复合蛋白酶嫩化基础上,采用谷氨酰胺转氨酶作用的最优工艺条件为酶用量5 U/g原料,作用温度45℃,作用时间80 min,pH 6.5,此条件下的样品持水力达90.51%.     

造纸黑液厌氧塘-化学混凝工艺处理技术的研究

造纸黑液厌氧塘-化学混凝工艺研究结果表明,厌氧塘作为造纸黑液的初级处理,在有机负荷率为0.2～0.8kg/m2.d时,COD去除率为30～42%,木质素去除率为40～50%;塘出水后处理采用化学混凝法,在泥浆投加量为2.45g/L(提高塘出水的SS),FeCl3投加量为0.91g/L时,COD和色度的去除率分别为84%和94%,最终出水可达到造纸行业的排放标准。     

美国新黑人文化运动及其影响

20世纪20年代,在美国纽约的哈莱姆地区,兴起了轰轰烈烈的新黑人文化运动,它以美国的黑人知识分子为先锋,盛极一时。同时,美国的白人知识分子也推波助澜,鼎力相助,有关黑人的民族文化得到一定的整理和发展,也使黑人的民族意识得到了提高。它虽然随着1929年美国经济大萧条的来临而结束,但仍不愧是一次唤起黑人民族自信心和民族自豪感的思想启蒙运动。     

Electrochemical behavior of insulin on pretreated carbon black electrode enhanced with silicon carbide nanostructure

We previously reported the direct electrochemical detection of insulin at bare carbon electrodes. Here a novel modified acetylene carbon black paste electrode(SiC/CB-CPE), based on the outstanding characteristics of silicon carbide nanostructure,was developed for the electrooxidation of insulin in alkaline solution and it was characterized by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) in 5 mmol/L Fe(CN)63-/4- solution. It is found that silicon carbide nanostructure doped into the CB-CPE greatly facilitates the redox electrochemistry of Fe(CN)63-/4- probe and the electrochemical oxidation of insulin. The electrooxidation of insulin is a one-electron and one-proton reaction and an irreversible adsorption-controlled electrode process. The anodic oxidation current increases linearly with the concentration of insulin from 1×10-7mol/L to1.2×10-6mol/L in 0.1 mol/L Na2CO3-NaHCO3 buffer solution(pH 10.0) and the detection limit was 50 nmol/L. In addition, the SiC/CB-CPE shows good sensitivity, reproducibility, renewability and capacity of resisting disturbance.     

变异系数的统计推断及其应用

变异系数是反映总体离散程度的重要指标。应用delta方法研究了样本变异系数的渐近分布,进一步构造了其置信区间及检验统计量,并用Monte Carlo方法给出了置信区间的模拟覆盖概率和检验的模拟功效,最后分析了一组实际考试成绩。