猪β干扰素基因17位丝氨酸突变体重组酵母表达载体的构建

根据猪β干扰素基因序列设计一对引物,并按酵母密码子的偏好性,在引物中对稀有密码子进行同义突变,即第3位的TAT基因突变为TAC,第7位的CGA基因突变为AGA,第164位的CGG基因突变为CGT。同时,利用聚合酶链式反应基因定点突变技术,把17位的半胱氨酸密码子TGT突变为丝氨酸密码子TCT,构建poIFNβSer17...     

pGH基因全序列ApaⅠ酶切位点多态性与生产性能的相关分析

本实验利用PCR-RFLP技术分析了约克夏和长白猪pGH基因ApaⅠ酶切位点多态性及其与生产性能的关系.结果表明,在pGH基因序列中共检测到5种基因型,4种等位基因,基因型频率和等位基因频率在2个猪品种间分布差异不显著;约克夏ApaⅠ酶切多态位点中,AC基因型个体在165日龄体重和70-165日龄日增重上显著高于AA基因型个体(P<0.1);但长白猪ApaⅠ多态位点不同基因型在这两个生产性状上的差异不显著.     

猪源纤维蛋白粘合剂对大鼠皮肤创伤的愈合及羟脯氨酸表达的影响

【】 目的 为促进皮肤创伤愈合提供实验依据,最终为临床新应用提供依据,探究猪源纤维蛋白粘合剂(FS)其对大鼠皮肤创伤的愈合及其对创面皮肤羟脯氨酸表达的影响,。方法 72只体重为160-200 g SD雄性大鼠随机分为空白对照组、白凡士林组和FS组,于背部制作直径为1.5 cm的全层圆形皮肤切除创面,每组各24只,空白对照组不做任何处理,白凡士林组和FS组则分别用医用白凡士林和FS涂抹伤口。术后3 d、7 d、14 d和21 d测量各组大鼠的皮肤伤口面积,计算各组皮肤创面愈合率,取术后7d和14d伤口皮肤标本进行HE病理组织学观察;并于术后7d、14d和21d取组织进行酶联免疫法测定愈合组织中羟脯氨酸蛋白含量。结果 在术后3 d、7 d、14 d和21 d时,FS组的伤口愈合率高于空白对照组,且其差异具有统计学意义(p<0.05)。HE染色结果显示在第7d时FS组胶原沉积高于空白对照组,血管新生数亦高于空白组、白凡士林组,差异均具有统计学意义 (p<0.05);在14 d时,与空白对照组相比,FS组胶原沉积较高且差异具有统计学意义(p<0.05),而血管新生数各组之间无统计学意义(p>0.05)。对各组创面组织中HYP含量进行测定,结果发现,在第7 d、14 d和21 d时,FS组大鼠皮肤创伤组织中HYP含量均明显高于空白对照组 (p<0.05)。结论 猪源纤维蛋白粘合剂能有效促进大鼠皮肤创伤的愈合,缩短愈合时间,其具有潜在的应用价值,为临床皮肤创伤治愈提供了新思路。     

High sensitivity of porcine cerebral arteries to endothelin

Summary The threshold concentration of endothelin to induce contractions in porcine cerebral arteries (anterior cerebral, Willis ring and basilar artery) was lower than those for coronary and renal arteries. The median effective concentrations (ED₅₀) of endothelin in cerebral arteries were also significantly lower than those for coronary and renal arteries. There was no significant difference in the sensitivity to endothelin among cerebral arteries, or between coronary and renal arteries. The maximal percentage of contractions induced by endothelin, as compared to that induced by 10^–1 M potassium chloride, was not significantly different between the arteries.     

Limited proteolysis of lactate dehydrogenase from procine heart with trypsin: Characterization and reactivation of the fragments

Summary The ternary complex formed by native lactate dehydrogenase (LDH) from porcine heart, NAD⁺ and sulfite, was digested with trypsin over a period of 12–16 h³. After removal of the ligands and residual native lactate dehydrogenase by ion exchange chromatography dimers were obtained which were almost inactive. The dimers were lacking a hexapeptide at the N-terminus; however, the secondary structure was the same as that of native lactate dehydrogenase. The circular dichroism spectra showed a dependence on temperature which suggested an equilibrium of two different structural states.The reaction of antibodies against native porcine heart LDH with the dimers restored the catalytic activity, and subsequently the dimers behaved similarly to the native enzyme. Addition of 1 M phosphate or NAD-sulfite to the dimers restored 80–90% of the catalytic activity. It could be demonstrated that the behaviour of the reactivated dimers, in contrast to that of the inactive dimers, was similar to the behaviour of native lactate dehydrogenase. For instance, ultracentrifugal analysis showed that dimers reactivated with NAD–SO₃ ^– were associated to give tetramers.The reaction of antibodies against native LDH with the dimers reactivated with NAD–SO ₃ ^– demonstrated that the native LDH and the dimers have the same surface determinants.     

Rudimentary study on humanization of porcine red blood cells:Enzymatic removal of galactose-α1,3-galactose antigen from porcine red blood cell

The serological and biochemical characterization of porcine red blood cells (pRBCs) are similar to human red blood cells,Porcine erythrocytes are considered as an alternative source for human blood transfusion.But there exist galactose-α1,3-galactose antigens (Galα1,3Galβ1,4galNAc-R,abbreviated αGal antigen ) on pRBCs,which can induce anti-αGai antibodies in human serum ,The αGal epitopes are the major antigen responsible for hyperacute rejection in exnotransfusion .In this study ,recombined soybean α-galactosidase (rSα-GalE) was used to remove the αGal antigens from pPRCs for humanization .The results showed that αGal antigen was eleared by rSα-GalE and the structure and function of rSα-GalE treated pRBC were normal.     

Xenozoonoses in xenotransplantation

Pig to human xenotransplantation is one of the possible ways to solve the problem of organ shortage, but the potential risk of xenozoonoses hinders the progress of xenotransplantation. Among pathogens that might cause xenozoonoses, porcine endogenous retrovirus (PERV) is undoubtedly the most noticeable. Current researches show that PERV exists in pigs' genomes and is able to express in multiple tissues and organs in pigs. Other experiments also show that PERV could successfully infect several human cell lines in vitro and could infect SCID mice through pig to mouse islet transplantation. The discussion and research on the risk of PERV is one of the hottest topics in current xenotransplantation, but the question of whether PERV will transmit to human through xenotransplantation has not been answered due to the lack of suitable animal models. More work should be done to evaluate the risk of xenozoonoses caused by PERV after pig to human xenotransplantation.     

猪白细胞介素-6基因的原核表达及其活性研究

用DNA重组技术，将已克隆的猪IL－6 cDNA片段插入pGEX-1λT质粒，转化大肠杆菌，以BamHI和Pst I酶切鉴定重组子，以IPTG诱导融合蛋白表达，并作RT－PCR及SDS－PAGE分析表达情况，从聚丙烯酰胺制备凝胶中回收融合蛋白，用MTT法测定重组蛋白刺激小鼠脾淋巴母细胞增殖反应的活性，并免疫家兔制备高免血清，得到高效表达猪IL－6的质粒pGPIL-6,RT-PCR确证pGPIL-6在大肠杆菌中能正确转录，经SDS－PAGE分析表达蛋白分子量为49kD，融合蛋白具有较高的促小鼠淋巴细胞增殖反应活性，以此免疫家兔，可制备滴度为1：128 000的兔高免血清。     

猪凝血酶的分离纯化与鉴定

本文报导以猪血为材料，制备凝血酶，血浆在低离子强度下经等电沉淀得优球蛋白，从该沉淀中采用稀盐溶液提取，氢氧化镁吸附和二氧化碳解吸等步骤获得凝血酶原粗品。后者经脑提取液激活，再经乙醇分级、ＤＥＡＥ－纤维素与磷酸纤维素离子交换层析和ＳｅｐｈａｄｅｘＧ－１００凝胶过滤，得凝血酶制品，经ＳＤＳ－ＰＡＧＥ分析，制品呈单一条带，分子量约为３９ｋＤ，比活达１６１０ＮＩＨＵ／ｍｇ蛋白，以活化的粗品活性为１００％，活性回收率为４８％，纯化倍数约为１０。