猪繁殖与呼吸综合征病毒ORF6基因在比赤酵母中的表达

根据酵母表达系统的密码子偏爱性、poly（A）信号以及外源基因mRNA5′端的二级结构等特性，对猪繁殖与呼吸综合征病毒（PRRSV）ORF6基因进行简并改造和人工合成，然后以正确的读码框架插和到分泌型母高效表达载体pPICZαA的α因子信号肽编码序列3′端，构建成酵母转移载体，用化学方法转化酵母菌GS115，和酶切鉴定证实，目的基因已整合到重组酵母菌染色体中。对重组酵母进行诱导表达，并通过SDS－PAGE和Western blot分析筛选，获得了一株高效表达目的蛋白的重组酵母菌，该重蛋白有免疫学活性，其表达水平可达2．0g／L，而未经改造的ORF6基因则不表达。     

猪圆环病毒2型ORF2基因在巴斯德毕赤酵母中的表达

为探索猪圆环病毒2型ORF2基因(PCV2 ORF2)的高效表达,本实验将ORF2基因整合到酵母表达载体p GAPZαA中,构建重组质粒p GAPZαA-ORF2。通过AvrⅡ酶切线性化,经电穿孔法转到毕赤酵母菌X33中。经ZeocinTM抗性筛选得到转化子,在GAP强启动子调控下,通过SDS-PAGE分析和Western blotting鉴定,结果证实Cap蛋白在酵母载体p GAPZαA中得到成功分泌表达。     

猪圆环病毒Ⅱ型ORF2基因在酵母中的表达

为探索猪圆环病毒Ⅱ型(PCVⅡ) ORF2基因的高效表达,将ORF2基因整合到酵母表达载体pPICZαC中,构建重组质粒pPICZαC-ORF2,通过SacⅠ酶切线性化,经电穿孔法转到毕赤酵母菌SMD1168。经Zeocin^TM抗性筛选得到转化子,通过SDS-PAGE分析和Western blotting鉴定,结果表明衣壳蛋白在酵母菌中成功分泌表达。     

印第安纳型水泡性口炎病毒核衣壳蛋白基因在毕赤酵母表达系统中的表达

将含有IN型VSV核衣壳蛋白基因的重组质粒pET-32a/N用EcoRI和NotI进行双酶切,目的基因克隆到表达载体pPICZαA,构建重组质粒pPICZαA/N。用SacI酶切线性化,并以电转化方法转化受体酵母菌GS115,PCR证实目的基因整合到重组酵母菌染色体中,经鉴定所获得的重组酵母菌株为Muts表型。用甲醇对重组酵母进行诱导表达,经SDS-PAGE和Westernblot鉴定,核衣壳蛋白基因在毕赤酵母中获得表达,目的蛋白分子量大小为约75kDa,表达量约占菌体总量的20%,并能够被VSV阳性血清所识别,可用于VSV的血清学检测。     

毕赤酵母(Pichia pastoris )分泌表达牛白细胞介素2

利用舍有强启动子PAOX1和α-因子信号肽序列的巴斯德毕赤酵母载体pPICZαA，构建出舍牛白细胞介素2(BoIL-2)基因的重组质粒BoIL2-pPICZαA。线性化的重组表达栽体转化到巴斯德毕赤酵母X-33及KM71H中，筛选Zeoein高抗性酵母菌株，甲醇诱导目的蛋白表达。经SDS-PAGE和Western blot检测表明，BoIL-2以融合蛋白形式在胞内表达，但没能分泌到胞外。通过BoIL-2在巴斯德毕赤酵母中的表达，重点讨论了信号肽、基因的偏爱性等对外源基因分泌表达的影响。     

猪圆环病毒1型ORF2基因的改造及其在大肠杆菌中的表达

根据GenBank中猪圆环病毒1型(PCV1)ORF2基因序列,设计合成了一对引物,对PCV1ORF2基因进行PCR扩增,将扩增出的ORF2基因(702bp)克隆入pMD18-T载体,筛选获得重组质粒命名为pMD-ORF2。由于ORF2前面有120多个信号肽和序列中有大量的稀有密码子,所以将ORF2进行改造并将改造的ORF2双酶切产物插入原核表达载体pET-32α与pET-41α,得到重组子命名为pET-ORF2-1与pET-ORF2-2。用IPTG进行诱导表达,收集菌液进行SDS-PAGE和Westernblot分析,结果表明PCV1-ORF2在pET-32α和pET-41α中获得了高效融合表达,其表达蛋白分子量约为30Kda和45Kda。     

马动脉炎病毒主要结构蛋白基因酵母工程菌的构建及鉴定

目的:构建马动脉炎病毒读码框ORF5、ORF6、ORF7主要结构蛋白基因全长片段的克隆载体及汉逊酵母穿梭载体,并获得重组工程菌,为下一步酵母表达重组目的蛋白奠定基础.方法:应用RT-PCR方法从病毒核酸中扩增ORF5、ORF6和ORF7读码框的全长基因,产物回收后分别与PUC18和PMD18-T载体连接并转化DH5α E.coli,经氨苄筛选及测序,建立克隆载体PUC18-GL、PUC18-M和PMD18T-ORF7;以构建的克隆载体为模板,用重新设计的引物构建了汉逊酵母分泌性穿梭载体,然后电转化至汉逊酵母基因组中.结果:所有重组质粒经 PCR和酶切鉴定均出现目的片段,测序结果证实正确,目的基因ORF5、ORF6与酵母重组成功.结论:构建了含有目的基因ORF5、ORF6的重组酵母工程菌,为实现分泌表达目的蛋白 ,进而研制病毒亚单位疫苗及诊断试剂提供了物质基础.     

马动脉炎病毒主要结构蛋白基区酵母工程菌的构建及鉴定

目的：构建马动脉炎病毒读码框ORF5、ORF6、ORF7主要结构蛋白基因全长片段的克隆载体及汉逊酵母穿梭载体，并获得重组工程菌，为下一步酵母表达重组目的蛋白奠定基础。方法：应用RT-PCR方法从病毒核酸中扩增ORF5、ORF6和ORF7读码框的全长基因，产物回收后分别与PUCl8和PMD18-T载体连接并转化DH5a E．coli，经氨苄筛选及测序，建立克隆载体PUC18-GL、PUC18-M和PMD18T-ORF7；以构建的克隆载体为模板，用重新设计的引物构建了汉逊酵母分泌性穿梭载体，然后电转化至汉逊酵母基因组中。结果：所有重组质粒经PCR和酶切鉴定均出现目的片段，测序结果证实正确，目的基因ORF5、ORF6与酵母重组成功。结论：构建了含有目的基因ORF5、ORF6的重组酵母工程菌，为实现分泌表达目的蛋白，进而研制病毒亚单位疫苗及诊断试剂提供了物质基础。     

番鸭细小病毒VP2基因在毕赤酵母中的表达及表达产物的鉴定

通过DNA重组技术,将克隆到的MDPV-Q和MDPV-26的VP2基因片段,经两种限制性核酸内切酶SaclI和Kp-nl的酶切,将酶切产物再克隆到表达载体pPICZαA中,得到表达重组质粒pPICZαA-M-Q VP2和pPICZαA-M-26 VP2.将这两种表达重组质粒分别转化到毕赤酵母(Pichia Pastoris X-33)中进行表达,经甲醇诱导和SDS-PAGE分析结果表明,MDPV-QVP2和MDPV-26 VP2基因片段的表达产物大小约为73kD,与理论预计相符.此外,本研究还意外地发现,重组质粒转化到酵母菌进行表达,在表达VP2结构蛋白的同时,还表达了一条大小约为60kD的蛋白条带.     

表达鸡α干扰素重组酿酒酵母菌的构建与鉴定

通过构建鸡α干扰素真核表达载体,以获得能够表达鸡α干扰素的酵母工程菌株。首先根据GenBank公布的鸡α干扰素基因序列设计上、下游引物,以略阳乌鸡基因组DNA为模板,PCR扩增鸡α干扰素基因片段。然后,利用基因重组技术将鸡α-干扰素基因插入真核表达载体,通过菌落PCR和DNA测序确定目标载体,构建成功后转化至酿酒酵母AH109,再通过营养缺陷培养、质粒提取和PCR鉴定带JMB440-ChIFN-α载体的重组酵母菌株。最终通过酵母培养、总蛋白收集、SDS-PAGE电泳和Western blot等,确定鸡α干扰素基因能够与酵母菌株重组,并表达α干扰素,蛋白条带大小约为23ku,与预期结果一致,表明成功构建了表达鸡干扰素基因的工程酵母菌株。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

中华人民共和国农业部公告 第267号

为贯彻落实《兽药生产质量管理规范》(简称《兽药GMP》),进一步推动兽药GMP实施进程,我部制定了《兽药生产质量管理规范检查验收办法》,现予公告。本公告自2003年6月1日起施行。附件:兽药生产质量管理规范检查验收办法二○○三年四月十日第一章 总则 第一条 为推动《兽药生产质量管理规范》(以下简称兽药GMP)的实施,规范兽药GMP检查验收工作,制定本办法。 第二条 农业部负责全国兽药GMP管理和检查验收工作;负责制修订兽药GMP检查验收管理规定;负责兽药GMP检查员队伍建设和监督管理工作,负责国际兽药贸易中GMP互认工作。 …     

鸡败血支原体垂直传播模式及其阻断方法

以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.