酸性蛋白酶、微生态制剂和抗生素对肉鸡生长性能的影响研究

选取1日龄健康AA肉鸡1200只,随机分成6组,分别饲喂在基础日粮中添加抗生素(作为对照组)及不同配比酸性蛋白酶与微生态制剂或抗生素(作为处理组).试验期为42 d,分为前期(1～21 d)和后期(22～42 d)两个阶段.结果表明:与抗生素对照组相比,第4组、第5组、第6组肉鸡体增重得到显著的提高,分别提高了15.6%、24%、16.3%(P<0.05),料重比分别降低了6.60%(P>0.05)、7.61%(P<0.05)、6.60%(P>0.05);各处理组能显著地增加空肠中乳酸菌数量(P<0.05),以添加0.01%酸性蛋白酶+0.005%微生态制剂效果最佳,其他各处理组之间乳酸菌数量差异不显著(P>0.05).     

联合应用生长激素和谷氨酰胺对短肠大鼠小肠粘膜IGF-1 mRNA表达的影响

选用 4 0只手术成功的SD短肠大鼠 ,按 2× 2析因实验设计随机分为 4组 ,分别给予常规全肠外营养 (TPN组 ,n =10 )、附加谷氨酰胺 (TPN +Gln组 ,n =10 )、附加生长激素 (TPN +GH组 ,n =10 )及附加谷氨酰胺和生长激素全肠外营养 (TPN +Gln +GH组 ,n =10 ) ,持续 6天 ,取 8只正常大鼠模拟手术后第 1天处死 ,作为基础对照组 (n =8)。应用放免分析法检测血生长激素和血IGF 1的水平 ,Northernblot方法检测残留小肠粘膜IGF 1mRNA表达。探讨了联合应用生长激素和谷氨酰胺防止小肠粘膜萎缩的可能分子机制。结果表明 ,GH组和GG组血浆GH和IGF 1水平较TPN和TPN +Gln组明显增高 (P <0 .0 1) ;TPN组小肠粘膜组织IGF 1mRNA表达明显低于对照组 (P <0 .0 1) ,TPN+Gln组和TPN +GH组小肠粘膜IGF 1mRNA的表达较TPN组明显增高 ;TPN +Gln +GH组小肠粘膜组织IGF 1mR NA的表达水平提高显著 ,高于TPN +GH组和TPN +Gln组 (P <0 .0 1)。这说明 ,生长激素和谷氨酰胺的联合应用可能通过上调小肠粘膜细胞IGF 1mRNA的表达 ,增加IGF 1的自分泌和旁分泌 ,发挥其促进细胞分裂增殖和抑制细胞凋亡作用 ,从而防止小肠粘膜萎缩的发生。     

6-苄基腺嘌呤对长根菇酶活性的影响

6—苄基腺嘌呤(6-BA)在适当浓度下，可促进长根菇的生长，通过测定长根菇相关酶类的活性变化，了解6-BA促进长根菇生长的一些机理．     

Molecular mechanisms of thrombin function

The discovery of thrombin as a Na⁺-dependent allosteric enzyme has revealed a novel strategy for regulating protease activity and specificity. The allosteric nature of this enzyme influences all its physiologically important interactions and rationalizes a large body of structural and functional information. For the first time, a coherent mechanistic framework is available for understanding how thrombin interacts with fibrinogen, thrombomodulin and protein C, and how Na⁺ binding influences the specificity sites of the enzyme. This information can be used for engineering thrombin mutants with selective specificity towards protein C and for the rational design of potent active site inhibitors. Thrombin also serves as a paradigm for allosteric proteases. Elucidation of the molecular basis of the Na⁺-dependent allosteric regulation of catalytic activity, based on the residue present at position 225, provides unprecedented insights into the function and evolution of serine proteases. This mechanism represents one of the simplest and most important structure-function correlations ever reported for enzymes in general. All vitamin K-dependent proteases and some complement factors are subject to the Na⁺-dependent regulation discovered for thrombin. Na⁺ is therefore a key factor in the activation of zymogens in the coagulation and complement systems.     

低温逆境下杏花蕾中保护酶、蛋白质、MDA含量变化初探

为了探明不同杏品种花蕾在低温逆境下,SOD、POD酶活性、MDA、蛋白质含量变化与抗寒性的关系,对5个杏品种进行了测定。     

偏重亚硫酸钠对葡萄保鲜效应研究

以葡萄重3％的偏重亚硫酸钠处理新鲜葡萄1天后，其Sod,Pod,Cat活性增高，膜脂过氧化受抑制，MDA不积累，细胞膜电导率也有一定增加，有机酸，抗坏血酸及糖等营养成分损失减少，表明偏重亚硫酸钠具有一定的保鲜效果。     

Effects of chronic caffeine feeding on the activities of oxygen free radical defense enzymes in the growing rat heart and liver

The purpose of the present study was to determine the relationship between concentration of Zn, Cu and Fe, and the catalase, glutathione peroxidase and superoxide dismutase activities in the heart and liver of newborn rats whose dams were fed a diet supplemented with caffeine. Heart Zn levels of the 22- and 30-day-old rats of the caffeine group showed a decrease, whereas liver Zn levels showed an increase compared to the control. Cu levels in the liver at day 22 in the caffeine group were less than in the control. Cu- and Zn-containing superoxide dismutase activities showed an increase in the hearts of the caffeine group compared to the control. The activity of catalase and glutathion peroxidase showed no difference in the heart and liver between the groups. The present study suggests the possible involvement of superoxide dismutase enzyme in the impairment of heart formation as a result of chronic caffeine intake in the early growing period.     

盐度骤降对点篮子鱼存活率及肝脏抗氧化酶活性的影响

水体盐度是影响鱼类生长的重要环境因素之一,为了解急性盐度胁迫对点篮子鱼(Siganusguttatus)存活率及肝脏超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-PX)活性的影响,设定盐度30(对照)、盐度20、盐度10、盐度5和淡水5个盐度梯度进行试验.结果表明：96 h内各组死亡率均为...     

外源水杨酸浸种对干旱胁迫下国槐根系抗氧化酶系的影响

采用向1/2 Hoagland营养液中按一定比例添加聚乙二醇(PEG—6 000)模拟干旱胁迫的方式,研究了外源SA浸种对干旱胁迫下国槐根系抗氧化酶系的影响。其结果表明:①与对照组相比,干旱胁迫不同程度地降低了国槐根系的SOD、POD、CAT活性等,明显增加了根系MDA含量水平。②使用适当浓度的SA浸种可以提高SOD、POD及CAT活性,也可以显著降低根苗MDA含量水平,SA浸种有利于缓解干旱胁迫带来的不良影响。③低浓度的SA浸种处理能够提高国槐根系抗旱性,缓解干旱胁迫伤害,而高浓度处理则加剧了干旱胁迫的伤害。1 mmol/L浸种具有提高国槐根系抗旱性的最佳效果。     

洱海下游肠道致病菌噬菌体分离与鉴定

目的:分离洱海下游水体中的肠道致病菌噬菌体,了解肠道致病菌污染情况。方法:通过噬菌斑法从洱海下游水体中分离和鉴定各种肠道致病菌噬菌体。结果:成功分离出了痢疾杆菌噬菌体、伤寒杆菌噬菌体、乙型副伤寒杆菌噬菌体、大肠杆菌噬菌体4种肠道致病菌噬菌体。结论:洱海下游水体存在痢疾杆菌、伤寒杆菌、乙型副伤寒杆菌、大肠杆菌污染,提示需进一步加强大理周边生活污水排放的治理工作。