猪流行性腹泻病毒的分子生物学特性以及胰酶对其作用机理

猪流行性腹泻病毒(PEDV)在体外分离培养需依赖胰酶,目前胰酶对猪流行性腹泻病毒的作用机理尚未完全清晰,文中从分子生物学方面阐述胰酶对猪流行性腹泻病毒的作用。     

Plasma trypsin level in horses suffering from acute intestinal obstruction

Gastrointestinal disorders in horses leading to endotoxic shock could have further consequences on other splanchnic organs such as the pancreas, as can be seen in humans suffering from septic shock. In this study, the range of enzymatically active trypsin (EAT) in healthy horses was established and is similar to the range observed in healthy humans. EAT values were determined in horses with acute abdominal crises on admission as well as during anaesthesia and in the postoperative phase. A significant increase in plasma EAT was found in 59% of the horses with surgical colic when compared to our established reference range. Significantly higher values were found in severe shock cases. When separated in groups according to the duration of colic before referral, significantly higher EAT values were observed in the non-survivor group compared to the survivor group of colics of short duration. EAT plasma values increased significantly during the postoperative phase, and were significantly higher in small intestine obstructions than in large bowel disorders. In human medicine, hypovolaemic or septic shock patients show an increase in pancreatic proteases. Splanchnic hypoperfusion during shock could lead to pancreatic damage resulting in trypsin liberation into the peritoneal space and an increase in plasma levels. Trypsin is able to activate inflammatory cascades and leucocytes and could play a role in multiple organ failure. Further studies are needed to evaluate the implications of changes in plasma trypsin in the disease process of equine acute abdomen and to demonstrate possible pancreatic damage.     

Toxicity of novel aromatic and aliphatic organic acid and ester analogs of trypsin modulating oostatic factor to larvae of the northern house mosquito, Culex pipiens complex, and the tobacco hornworm, Manduca sexta

Eight non-peptidic chemical analogs of trypsin modulating oostatic factor (TMOF, NH₂-YDPAP₆), an insect hormone inhibiting trypsin biosynthesis in mosquitoes, were synthesized based on the structure of the native peptide. The median lethal concentration (LC₅₀) for the chemical analogs, TMOF and FDPAP (a peptidic analog of TMOF) was estimated for larvae of the northern house mosquito, the Culex pipiens complex, using a static 5-day bioassay. Four of these compounds demonstrated the same larvicidal activity as TMOF, while three of these compounds were 1.2-2.5-fold more active than TMOF. The compounds introduced by injection were toxic to fourth instars of the tobacco hornworm, Manduca sexta, except for TMOF, FDPAP, and PPHEN. Injection of TMOF and FDPAP into fourth stadium and TMOF into second stadium M. sexta had no effect on trypsin activity, growth, or mortality. Apparently the mosquito hormone is inactive in the tobacco hornworm at the developmental stages examined. Three TMOF analogs (CHEA, PHEA, and PHA) demonstrating the highest activity by injection in M. sexta were also found to be toxic by injection in fourth instars of the tobacco budworm, Heliothis virescens, and the cotton bollworm, Helicoverpa zea, as well as adult male German cockroaches, Blattela germanica. A two-choice feeding bioassay with H. virescens indicated that at least one of the TMOF analogs, PHEA, has anti-feeding properties.     

0～3周肉仔鸡消化道酶发育规律的研究

本试验以０～３周Ａｖａｉｎ商品代肉仔鸡公雏为研究对象,测试０,４,７,１０,１４,１７和２１日龄肉仔鸡体重,消化道器官重量,胰腺和肠道食糜中淀粉酶、胰蛋白酶、糜蛋白酶和脂肪酶活性的变化,基本摸清了０～３周肉仔鸡体重、消化器官的生长规律及消化道酶的发育规律。试验结果表明：（１）肉仔鸡在４～１０日龄日均相对生长率达到最大值（平均每天增重达１９％）,１０日龄后下降,到１４～２１日龄,基本维持在１３％～１４％左右;（２）各器官的相对重量（ｇ／ｋｇ体重）达到峰值的时间并不一致,腺胃和肌胃的相对重量在４～７天为最高,肝和胰在７～１０天,小肠在７天左右;（３）从异速生长的指标看,肌胃的最大增长倍数是体重增长倍数的１．５倍,腺胃是２倍,肝脏是２．３倍,小肠是３倍,胰腺达６倍;（４）小肠内容物的相对重量（ｇ／ｋｇ体重）在４～１０日龄达到最大值,以后呈下降趋势;（５）胰腺和肠道的消化酶活性（活性单位／ｋｇ体重）基本上随着日龄的升高而上升。在胰腺,淀粉酶、胰蛋白酶、糜蛋白酶和脂肪酶活性均在１０,７,２１和１０日龄达到峰值。在肠道,淀粉酶、胰蛋白酶、糜蛋白酶和脂肪酶活性均在１０日龄达到峰值。从消化道酶的分泌情况看,肉仔鸡早期消化酶     

花生种子胰蛋白酶抑制剂与抗黄曲霉侵染的关系

通过丙酮分级沉淀和DEAE-Sephadex A50离子交换柱, 从花生种子醋酸提取液中分离纯化出具有胰蛋白酶抑制剂活性的物质. SDS-PAGE电泳图谱显示, 纯化的胰蛋白酶抑制剂是以二聚体形式存在, 分子量分别为17.1和10.3 kDa, 纯化的胰蛋白酶抑制剂在体外能显著地抑制黄曲霉(Aspergillus flavus)孢子的萌发和菌丝的生长, 表明胰蛋白酶     

Influence of trypsin on the dynamic mechanical properties of intact RBC membrane

AIM: To study the influence of trypsin on the membrane dynamic mechanical properties and the surface charge density of single living intact red blood cell (RBC). METHODS: Young and old RBCs were separated from health adult human blood using the density gradient centrifugation. Then RBCs at different ages were incubated with trypsin at different concentration at 37 ℃ for 60 min. The surface negative charge density of RBCs was determined using ZetaPLUS potential analyzer. The size and membrane bending elastic modulus (Kc) and shear elastic modulus (μc) were determined by fast micro-image analyzing technology. RESULTS: (1) The surface negative charge density of normal and trypsin-treated old RBCs was significantly lower than those of normal and trypsin-treated young RBCs respectively (P<0.01). (2) The contact area of normal old RBCs was significantly smaller than that of normal young RBCs(P<0.05), but there was no difference in shape between normal young RBCs and normal old ones. Trypsin reduced the size of RBCs but did not affect the shape and size of both young and old RBCs. (3) The Kc and μc of normal old RBCs membrane were markedly larger than those of normal young RBCs respectively (P<0.05). The Kc and μc of young and old RBCs membrane were both increased at different concentration of trypsin. CONCLUSION: The surface negative charge density of young and old RBCs decreases, and the membrane elastic modulus of young and old RBCs membrane increases after treatment with trypsin. Therefore, the mechanical deformability of RBCs membrane is reduced.     

胰蛋白酶水解酪蛋白生产CPP水解工艺条件的研究

本研究利用胰蛋白解水解酪蛋白制取ＣＰＰ,通过旋转回归设计研究了底物浓度为１５％,水解１ｈ时酶－底物浓度比（〔Ｅ〕／〔Ｓ〕）,ｐＨ值和温度（Ｔ）对水解度（ＤＨ）的影响,建立了数学模型,根据Ｎ／Ｐ,ＣＰＰ得率优化水解条件为：〔Ｅ〕／〔Ｓ〕＝０．８２％,ｐＨ＝７．５,Ｔ＝４８℃,ｔ＝２ｈｒ,得出最适水解度为９．５％。     

不同盐度对弓斑东方鲀消化酶活性的影响

本研究探讨了不同水体盐度对弓斑东方鲀α-淀粉酶、胃蛋白酶和胰蛋白酶活性的影响,同时得出最适于该鱼种消化吸收养分的盐度值,以发挥其生长潜力.试验用360尾鱼,分为4个处理(淡水对照,盐度8‰、18‰和35‰),每处理3个重复,每个重复30尾,通过15 d饲养试验,采样时间分别为:第1天、第4天、第7天和第15天.结果显示:随着盐度的增加,α-淀粉酶、胃蛋白酶和胰蛋白酶的活性有显著变化(P<0.05).在试验后期,α-淀粉酶活性在盐度18‰时显著高于盐度8‰和35‰的情况(P<0.05);胃蛋白酶活性则在8‰和18‰2种盐度下有显著差异(P<0.05);胰蛋白酶活性在8‰时最大,显著高于35‰和18‰处理(P<0.05).试验结果表明弓斑东方鲍饲养的水体盐度为8‰～18‰时能更有效的促进其消化酶的活性.     

亲和层析纯化猪胰蛋白酶的研究

采用猪胰蛋白酶的天然抑制剂-鸡卵类粘蛋白(CHOM)作为配基合成亲和吸附剂,从猪胰脏的粗提液中,通过亲和层析直接获得高纯度的胰蛋白酶.此法具有操作简便、产品纯度、比活力和获得率高等优点.     

河北省野生大豆天然群体中胰蛋白酶抑制剂蛋白的多态性

 在河北省搜集了东北部山区、东北部平原、白洋淀湖泊区、西南丘陵山区等 18个天然野生大豆群体的 4 6 1份植株种子样本 ,调查其Kunitz型胰蛋白酶抑制剂蛋白 (KTI)的形态及蛋白位点在野生大豆天然个体群体及地理的频率变化。结果显示超过 5 0 %个体群体的KTI位点是多态的 ,18个天然个体群体中 12个群体形态是由Tia和Tib构成的混合群体。这次测定的河北野生大豆中没有发现Tic形态存在。在 12个混合群体中 ,4个群体发现存在Tia/Tib杂合种子 ,约占调查群体的 2 2 % ,在野生大豆总群体中至少有 1%的异交率。河北天然野生大豆Tia基因频率约占 85 % ,Tib约 15 %。地理上 ,东北部山区和平原生态区比南部的白洋淀和西南丘陵山地生态区有较高的Tib频率 ,无论在南部或北部 ,山区生态区Tib频率高于平原生态区 ,同时山区生态区内的个体群体间的基因频率差异变化程度高于平原群体间的变化 ;个体群体的基因频率没有看到与地理距离有相关性。白洋淀湖泊生态区虽然有河北最大的野生群落 ,但是KTI位点是Tia单态的 ,湖内和湖外群体KTI位点是一致的单态性 ,暗示白洋淀区域野生群体间受湖水流动的影响 ,使Tia型种子在群体传播形成一个单态优势型 ,也许这个区域的野生大豆遗传背景较其它地区群体狭窄。在这个研究中 ,我们还首