血管紧张素转换酶2在维持肠道稳态中的作用

血管紧张素转换酶2(ACE2)是首先克隆出的人类血管紧张素转换酶(ACE)的同源基因,是肾素-血管紧张素系统(RAS)的关键调节因子,其主要通过水解血管紧张素Ⅱ(AngⅡ)生成血管紧张素1-7[Ang(1-7)]从而发挥舒张血管、抗炎、抗增殖等作用。近期研究发现,ACE2不仅对心血管和肾功能等具有明显的调控作用,对抑制肠道炎症、维持肠道稳态、保护肠道健康等同样具有积极的影响。当前对ACE2在肠道健康领域的研究较少。论文就ACE2通过影响肠道微生态对维持肠道稳态作用的研究进行综述,为发掘ACE2的新功能提供参考。     

Evaluation of the PATHFAST Chemiluminescent Enzyme Immunoassay for Measuring Progesterone in Whole Blood and Serum of Mares

Evaluation of a new chemiluminescent enzyme immunoassay, the PATHFAST assay system (PATHFAST), for measurement of circulating progesterone in mares was performed. Five mares at the mid-luteal stage were administrated a single i.m. injection of prostaglandin F2α analog (PGF2α; cloprostenol 250 μg/ml), and then blood samples were collected from the jugular vein at 0, 15, 30 and 45 min, at one-hour intervals until 24 and at 48 hr via a catheter in the jugular vein. To monitor the physiological changes in circulating progesterone in mares after induced luteolysis, concentrations of progesterone in whole blood and serum samples were measured by PATHFAST. In addition, concentrations of progesterone in serum samples measured by PATHFAST were compared with those measured by radioimmunoassay (RIA) and enzyme immunoassay (EIA). Using PATHFAST, the serum concentrations of progesterone in mares correlated highly with those of whole blood samples (r=0.9672, n=88). The serum concentrations of progesterone as measured by PATHFAST correlated well with RIA (r=0.9654, n=88) and EIA (r=0.9323, n=112). An abrupt decline in circulating progesterone in whole blood samples was observed within 2 hr (50%), followed by a gradual decline until 48 hr later. The results for progesterone in whole blood samples correlated highly with those in serum samples, and the declining pattern paralleled that of the serum samples. These results demonstrated that PATHFAST is useful in the equine clinic as an accurate diagnostic tool for rapid assay of progesterone within 26 min, using unextracted whole blood.     

酶固定化技术的应用

固定化酶便于运输和贮存,有利于自动化生产,是近年发展起来的酶应用技术。介绍了酶固定化技术的应用,包括传统酶固定化技术的应用、利用不同载体材料的酶固定化技术的应用、利用不同载体材料改性后的酶固定化技术的应用以及新型酶固定化技术的应用。     

Comparison of Some Pharmacokinetic Parameters of 5 Angiotensin-Converting Enzyme Inhibitors in Normal Beagles

This study was designed to determine the degree of inhibition of the angiotensin-converting enzyme (ACE) in 5 normal dogs given single doses of conventionally used ACE inhibitors (ACEis). In addition the time required for that inhibition to return to 50% of the difference between maximum and zero (control values) was measured as an estimate of duration of action. The 5 ACEis (with dosages given in parentheses) were bena/april (0.5 mg/kg), captopril (2.0 mg/kg), enalapril (0.5 mg/kg), lisinopril (0.5 mg/kg), and ramipril (0.25 mg/kg). Blood samples for ACE activities were obtained before dosing and at 1.5, 3.0, 6.0, 12.0, and 24.0 hours after dosing. All ACEis except captopril decreased ACE activities to approximately 25% of control by the 1.5-to 3.0-hour sample, and ACE activities returned to 50% of the difference by the 12-hour sample. The value of ACE activity returned to normal by 24 hours for benazapril, whereas values for ACE activity remained below normal for enalapril, lisinopril, and ramipril at 24 hours. For captopril, however, ACE levels decreased to approximately 80% of control by the 1.5-hour recording, and returned to levels not different from control by the 3-hour recording. Based upon this study performed on normal dogs given a single dose, no pharmacokinctic advantage or disadvantage is apparent for any ACEi except captopril, which, at the dosage used, decreased ACE levels to a much lesser degree and shorter time.     

中药复方对山羊的影响:Ⅲ·瘤胃纤维降解酶及血清酶活性

试验旨在研究中药复方对山羊瘤胃纤维降解酶及血清酶活性的影响。选择6头健康的体重相近的安装有永久性瘤胃瘘管的周岁大足黑山羊羯羊,按3×3重复拉丁方试验设计,随机分为3组,1个对照组和2个处理组。对照组饲喂基础日粮,2个处理组分别在基础日粮上给每头羊日喂15 g复方Ⅰ和复方Ⅱ(由藿香、苍术、黄柏和生石膏等中药按不同比例组成)。结果表明:2种复方均能提高山羊瘤胃内pH及微晶纤维素酶、羧甲基纤维素酶、纤维二糖酶和木聚糖酶等纤维降解酶活性;2种复方均能降低山羊血清谷丙与谷草转氨酶、乳酸脱氢酶、肌酸激酶及碱性磷酸酶活性,仅提高血清α-淀粉酶活性。研究结果提示,中药复方可提高瘤胃纤维降解酶活性,改善机体组织器官的健康状况。     

动物疾病预防诊疗与酶的关系

本文论述了酶与预防和治疗家畜疾病的关系,以及常见的一些应用。酶作为生物催化剂,几乎参与动物机体内所有的代谢反应,酶的活性异常必然导致代谢异常。酶与动物疾病的发生发展、动物疾病的预防、疾病的分析及治疗有着密切的关系,应用越来越广。     

丝素作为固定化酶载体材料的研究进展

酶的固定化在化学、生物医学以及生物感应器等领域应用较广。固定化酶的效果在很大程度上取决于载体结构。丝素作为固定化酶载体材料有其独特的优势。本文综述了国内外以不同的丝素形态作为固定化酶载体材料的研究进展,重点介绍了非纳米丝素固定化酶和纳米丝素固定化酶（丝素纳米颗粒和丝素纳米纤维）的研究进展。     

饲料酶制剂种类及应用前景

本文介绍了几种常用饲料酶制剂，通过作用及需求分析对酶制剂的应用前景进行展望，提出合理利用饲料酶制剂。     

饲粮中添加苜蓿草粉或发酵苜蓿草粉对鹅生长性能、血清抗氧化酶及消化酶活性的影响

本试验旨在研究饲粮中添加苜蓿草粉或发酵苜蓿草粉对鹅生长性能、血清抗氧化酶及消化酶活性的影响。选用162只狮头鹅,随机分为9组,每组3个重复,每重复6只鹅。对照组饲喂基础饲粮,试验组饲喂分别添加5%、10%、15%和20%的苜蓿草粉或发酵苜蓿草粉的试验饲粮。试验期35 d。结果表明:1)饲粮添加苜蓿草粉或发酵苜蓿草粉对鹅的平均日增重产生显著二次和交互影响(P0.05),对平均日采食量的线性和交互无显著影响(P0.05),对料重比无显著影响(P0.05)。饲粮添加10%发酵苜蓿草粉组,鹅的平均日增重最高,较对照组提高了19.48%(P0.05)。2)饲粮中添加苜蓿草粉对鹅血清谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量有显著交互影响(P0.05),5%、10%苜蓿草粉组及5%发酵苜蓿草粉组血清GSH-Px、SOD和CAT活性与对照组差异不显著(P0.05),其他各组与对照组差异显著(P0.05)。3)饲粮中添加苜蓿草粉对胃蛋白酶、胰脂肪酶、十二指肠蛋白酶和脂肪酶活性无显著影响(P0.05)。饲粮中添加苜蓿草粉或发酵苜蓿草粉对胰蛋白酶、胰淀粉酶活性产生显著二次和交互影响(P0.05)。10%苜蓿草粉组胃蛋白酶、胰淀粉酶、十二指肠淀粉酶活性显著高于对照组(P0.05),但与5%苜蓿草粉组无显著差异(P0.05)。由此可见,在鹅饲粮中添加一定量的苜蓿草粉或发酵苜蓿草粉可以促进其生长,提高血清抗氧化酶和消化酶活性,添加发酵苜蓿草粉效果更好。     

论我国酶制剂工业的发展

分析了我国酶制剂工业的发展现状及酶制剂工业面临的主要问题,并介绍了酶制剂工业产品在生产生活中的应用,如在面包焙烤业、果蔬加工业、造纸业、啤酒业、纺织业等行业的应用,以期为进一步研究酶制剂和促进酶制剂工业的发展提供一定的参考。     

微生物胞外酶研究进展

近年来微生物胞外酶的意义已引起广泛关注,成为最活跃的研究领域之一。文章就其研究概况作一综述。     

氯霉素化学发光酶联免疫检测方法的建立

在常规酶联免疫法(ELISA)的基础上,用辣根过氧化物酶标记氯霉素与牛血清白蛋白偶联后免疫小鼠制得的单克隆抗体,并优化抗体工作浓度、反应时间等试验参数,建立了一种简便、快速、准确的氯霉素(CAP)残留一步式化学发光酶联免疫检测方法。结果表明:该方法最佳检测范围为20～1620 pg/mL,IC50值达59.911 pg/mL,检测限为9.3 pg/g,可检出国际规定的CAP残留标准限量值以下的残留量。与常规ELISA检测方法相比,不仅提高了检测限和灵敏度,而且反应时间缩短了60 min。采用一步式化学发光酶联免疫检测氯霉素残留,可以大幅度缩减检测时间,更符合快速检测的要求。     

Enzyme Histochemical Studies of the Normal Pig Kidney

The activity and localization of NAD(P)H-tetrazolium reductase, lactate dehydrogenase, isocitrate dehydrogenase, succinate dehydrogenase, glueose-6-phosphate dehydrogenase, α-glycerophosphate dehydrogenase, acid phosphatase, and alkaline phosphatase in the kidney of 11 female pigs were examined.The pig kidney showed a higher activity of NAD (P) H-tetrazolium reductase in the distal tubules compared with the kidney of rat, mouse, rabbit, dog, cat, and man. The activity of succinate dehydrogenase and alkaline phosphatase was the same in the pig kidney as in the kidney of other examined species. In the pig kidney glucose-6-phosphate dehydrogenase precipitated in situ, while in rat and mouse this enzyme has proved to be highly diffusible.     

常用酶制剂型保鲜剂对乳品的抑菌机理及其应用

生物酶制剂无毒、无味、无嗅,添加到成分复杂的原料乳中不会引起不必要的化学变化,不损害乳品的质量,而且对底物有严格的专一性,催化效率高、用量少。综述了在生产过程中乳酸链球菌素、溶菌酶、葡萄糖氧化酶、过氧化氢酶等酶制剂型保鲜剂的抗菌机理及应用,并探讨了酶制剂型保鲜剂的优化配比。     

植物凝乳酶凝乳特性的研究

从凝乳酶的最适作用温度，酶的热稳定性，ｐＨ对植物凝乳酶活性的影响，植物凝乳酶对ｐＨ的稳定性，Ｃａ＾２＋对植物凝乳酶活性的影响，以及底物浓度对植物凝乳酶凝乳活性的影响等方面深入阐述植物凝乳酶乳特性，并分别进行了讨论。     

蜂胶黄酮苷酶解与抗氧化活性的探讨

蜂胶中含有很多的黄酮苷类物质,而黄酮苷类物质由于自身的抗氧化性能和在人体不能被充分利用使其抗氧化活性没有黄酮苷元的抗氧化活性强.探讨酶法降解黄酮苷的研究现状和在蜂胶加工中应用的可能性,得出结论,酶法降解蜂胶中的黄酮苷能够显著增强蜂胶的抗氧化活性,能够为蜂胶更深层次的利用奠定基础.     

绵羊乳酪蛋白血管紧张素转换酶抑制肽的制备与鉴定

以绵羊乳酪蛋白为原料,采用中性蛋白酶水解制备生物活性肽,研究酶解时间对酶解产物水解度和血管紧张素转换酶(angiotensin converting enzyme,ACE)抑制率的影响,利用液相色谱-质谱联用技术对水解产物进行分析和鉴定,筛选具有潜在ACE抑制作用的生物活性肽.结果表明:酶解时间达到300 min时,水...     

一株高产内切纤维素酶贝莱斯芽孢杆菌的产酶条件优化及酶学性质分析

试验旨在对一株杜仲树皮内生菌贝莱斯芽孢杆菌(Bacillus velezensis)的内切纤维素酶(CMCase)进行产酶条件优化及酶学性质分析,为探究贝莱斯芽孢杆菌CMCase的相关特性提供参考依据。采用单因子试验设计,分别优化pH、接种量、温度、时间、碳源和氮源等发酵条件,并探讨温度、pH、底物专一性、金属离子及表面活性剂对CMCase的影响。结果表明,以玉米秸秆为碳源(30 g/L)、豆粕为氮源(30 g/L)、3%接菌量、pH 7.0的条件下37℃培养48 h,贝莱斯芽孢杆菌157的CMCase最高可达(5.14±0.18) U/mL。经CMCase酶学性质分析发现,贝莱斯芽孢杆菌157的最适酶反应温度为60℃,最适pH为5.0;温度稳定性试验发现,在40和50℃时,相对剩余酶活力均高于80%,随着温度的升高,酶活力逐渐降低,当温度高于55℃,相对剩余酶活力约为50%;pH稳定性试验发现,在pH 5.0～10.0之间耐受性良好,相对剩余酶活力均高于90%,随作用时间的延长,相对剩余酶活力变化不大。贝莱斯芽孢杆菌157 CMCase属于典型内切型纤维素酶。Na^+、Mg²⁺、Ca²⁺可促进贝莱斯芽孢杆菌157 CMCase酶活力,而Co²⁺、Hg²⁺、Fe²⁺、Cu²⁺和SDS抑制CMCase酶活力;表面活性剂Tween-80、Tween-20、Triton X-100对贝莱斯芽孢杆菌157 CMCase无影响。本试验通过对贝莱斯芽孢杆菌157进行产酶条件优化及CMCase酶学性质分析发现,贝莱斯芽孢杆菌157 CMCase具有产酶量高,耐受pH范围广的特点,在饲料添加剂、洗涤剂和造纸领域中具有一定的应用价值。