ST细胞酵母双杂交cDNA文库的构建及鉴定

为了筛选与猪细小病毒（porcine parvovirus,PPV）结构蛋白VP2相互作用的宿主蛋白,深入研究病毒入侵及致病的分子机制,本试验建立了ST细胞酵母双杂交cDNA文库。采用RNeasy Min Kit提取ST细胞的总RNA,反转录合成cDNA第一链之后,通过SMART技术合成了双链cDNA,并利用同源重组的方法,构建了ST细胞的酵母cDNA文库。结果显示,文库滴度为8.1×10⁸ CFU/mL,插入的双链cDNA片段大小为250~1 000 bp,平均大小约为500 bp,文库的重组率为96%。此文库可用于筛选与病毒相互作用的ST细胞宿主蛋白,为进一步阐明病毒的致病机制奠定了基础。     

绵羊卵巢组织细胞酵母双杂交cDNA文库的构建及鉴定

试验旨在构建绵羊卵巢组织细胞的cDNA文库,为进一步研究绵羊卵巢中蛋白互作机制提供工具。本研究以不同发情周期的绵羊卵巢组织为材料,利用TRIzol试剂提取绵羊卵巢组织细胞总RNA,应用SMART技术经过长链PCR(LD-PCR)合成双链cDNA(ds cDNA),通过CHROMA SPIN~(TM)+TE-400柱纯化得到ds cDNA,并与线性pGADT7-Rec共转化酵母Y187感受态细胞。用同源重组的方式,在酵母细胞内构建绵羊卵巢组织细胞酵母双杂交cDNA表达文库。结果构建了含有3×10~8个重组子的绵羊卵巢组织cDNA文库,插入片段长度多数为500～2 000 bp,重组率达96%,重组子中平均插入的片段长度为1 000 bp,文库滴度为2×10~7cfu/mL,符合建库标准。     

牛源犬新孢子虫酵母双杂交cDNA文库的构建及鉴定

旨在构建酵母双杂交牛源犬新孢子虫cDNA表达文库,进而为研究新孢子虫功能结构以及为其入侵宿主致病机理研究提供良好的试验体系。体外培养牛源犬新孢子虫延边株,纯化并提取虫体总RNA,应用SMART技术合成双链cDNA(ds cDNA)。利用CHROMA SPINT+TE-400Columns纯化柱纯化ds cDNA,并与线性化的p GADT7-Rec共转化酵母菌菌株Y187,以同源重组的方式在酵母细胞内构建牛源犬新孢子虫酵母双杂交cDNA表达文库。结果显示,文库容量为5.78×108cfu/m L,随机挑取23个单克隆进行菌落PCR检测,插入的双链c DNA片段大小为400~4 000 bp,平均长度在2 000 bp左右,文库重组率为100%,此文库可用于酵母双杂交筛选。试验为筛选新孢子虫与宿主之间相互作用蛋白研究奠定了基础。     

鸭胚成纤维细胞酵母双杂交cDNA文库的构建与鉴定

为了解与坦布苏病毒(TMUV)E蛋白相互作用的宿主细胞蛋白,本试验制备鸭胚成纤维细胞(DEF)。采用Trizol法提取细胞总RNA,通过LD-PCR技术合成双链cDNA,经CHROMA SPIN TE-400column纯化后,与pGADT7载体连接,利用同源重组的方法克隆到Y187酵母感受态细胞,构建了鸭胚成纤维细胞的cDNA文库。结果显示:构建的文库滴度为3×107 CFU/mL,文库插入的双链cDNA片段为0.5~2.5kb,平均约为1.5kb,符合酵母双杂交筛选的要求。     

猪肺泡巨噬细胞酵母双杂交cDNA文库的构建与鉴定

为研究猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)与猪肺泡巨噬细胞(porcine alveolar macrophages,PAM)蛋白质间相互的作用,本研究使用SMART技术成功构建了猪肺泡巨噬细胞酵母双杂交cDNA文库。首先提取PAM总RNA,使用SMART RACE法经LD PCR合成双链cDNA,运用SMART技术,通过同源重组的方法将双链cDNA与pGADT7-Rec质粒共转化进酵母Y187感受态,再利用营养缺陷的方法在SD/-Leu平板上筛选阳性克隆,最终构建的文库滴度达到了6.96×10~7 CFU/mL,重组率初步计算达到95%,插入片段范围在200~2 000bp。本研究为PRRSV致病蛋白的筛选以及相关疾病的研究奠定了基础。     

柔嫩艾美耳球虫子孢子酵母双杂交cDNA文库的构建

为了筛选柔嫩艾美耳球虫子孢子入侵相关的蛋白,利用酵母双杂交体系构建了柔嫩艾美耳球虫子孢子酵母双杂交cDNA文库。提取纯化的子孢子总RNA,经MMLV-RT反转录合成cDNA第一链后,利用LD-PCR扩增合成双链cDNA(ds cDNA),dscDNA经纯化柱CHROMA SPINT+TE-400 Columns纯化剔除小于200 bp的片段。将纯化后dscDNA、pGADT7-Rec及Carrier DNA共转化到已经制备好的酵母感受态细胞Y187中,dscDNA与pGADT7-Rec以同源重组的方式在细胞内进行连接,经过缺陷性培养基(SD/-Leu)的筛选得到酵母双杂交cDNA文库。结果显示,构建的柔嫩艾美耳球虫子孢子酵母双杂交cDNA文库的转化率为4.33×105/μg pGADT7-Rec,文库滴度为3.62×107 cfu/m L。随机挑取32个单克隆进行PCR检测,插入片段大小为200~2000bp,重组率为93.75%,并以该文库作为模板,用柔嫩艾美耳球虫5对特异性引物进行PCR扩增,获得了这5个基因片段。结果表明成功构建了柔嫩艾美耳球虫子孢子酵母双杂交cDNA文库,为进一步筛选和研究球虫入侵互作蛋白奠定了基础。     

猪小肠上皮细胞酵母双杂交cDNA文库的构建及鉴定

为了更系统的研究病毒在猪肠道内侵入及致病的分子机制,本试验以猪小肠上皮细胞(intestinal epithelial cells,IEC)为模型,应用RNeasy Min Kit从猪IEC中提取细胞总RNA,反转录后,利用SMART技术合成双链cDNA(ds-cDNA),通过同源重组的方法构建猪IEC酵母双杂交cDNA文库。结果显示,文库的滴度为8.4×10⁸ CFU/mL,插入的ds-cDNA片段大小为0.5~2.0 kb,平均长度约为1.1 kb,文库重组率为100%。此文库为筛选与猪腹泻病毒相互作用的宿主蛋白及进一步阐明病毒的致病机制奠定了基础,为研制有效的药物或疫苗提供了依据。     

猪小肠上皮细胞酵母双杂交cDNA文库的构建

猪小肠上皮细胞(intestinal epithelial cell,IECs)是猪流行性腹泻病毒(Porcine epidemic diarrhea virus,PEDV)在宿主体内感染的靶细胞,为了研究PEDV在体内与宿主细胞蛋白之间的互作关系以便于揭示其致病机理,本研究以IECs为研究对象,提取了IECs的总RNA,利用SMART技术经过反转录、扩增和纯化获得双链cDNAs后,将其与pGADT7-Rec和carrier DNA共同转化至酵母Y187菌株,进行选择性培养基(SD/-Leu)筛选以及文库容量及质量的鉴定。结果显示,本研究构建的IECs-cDNA文库其库容量为1.3×10~8 pfu/mL,插入cDNA片段长度为250～2500 bp,文库阳性率达100%。本研究结果表明构建的IECs-cDNA文库具有较好的多态性,为后续研究PEDV与宿主细胞蛋白之间的互作关系提供了有力支持。     

酵母双杂交筛选与呼肠孤病毒σ1、σ1S互作宿主蛋白

提取猪肠上皮细胞IPEC-1的总RNA,构建了IPEC-1的靶标cDNA文库。随机挑取文库克隆子进行PCR扩增,发现插入片段长度为200～1 500bp,文库的重组率为100%。以猪源呼肠孤病毒GD-1株S1基因节段为模板,通过PCR扩增,定向克隆构建诱饵载体pGBKT7-S1、pGBKT7-S1s。通过菌落PCR和测序验证的质粒被转化至酵母菌株Y2H Gold,诱饵载体pGBKT7-S1、pGBKT7-S1s均能在酵母细胞中正确表达出对应的σ1和σ1S蛋白,且无自激活活性,对酵母细胞无毒性,满足文库筛选实验的要求。将含有pGBKT7-S1、pGBKT7-S1s的酵母菌株Y2H Gold分别与靶标cDNA文库菌株Y187进行杂交,筛选、验证、测序后得到13个与σ1、6个与σ1S相互作用的宿主蛋白,其中的1个蛋白与σ1、σ1S同时存在相互作用。本试验成功构建了适用于研究肠道细菌、病毒作用机制的猪肠上皮细胞IPEC-1cDNA文库,筛选出18个与猪呼肠孤病毒σ1或σ1S的互作蛋白,为研究呼肠孤病毒与宿主相互作用,以及鉴定疾病控制的新靶标提供了线索。     

鸡法氏囊B淋巴细胞三框cDNA表达文库的构建

分离纯化3周龄SPF鸡法氏囊B淋巴细胞的mRNA,以5'端生物素标记的Oligo(dT)primer为引物反转录后连接3种读码框的Adapter,层析柱分级纯化,通过BP重组反应分别构建3种读码框的cDNA入门文库,平均滴度分别为1×105 CFU/mL、1×105CFU/mL、1.2×105CFU/mL,文库总容量分别为1.2×106CFU、1.2×106CFU、1.5×106CFU,平均插入片段分别为1 270 bp、1 190 bp和1 120 bp,阳性重组率均为100%.将3种读码框的cDNA入门文库扩增后提取质粒,取等量的质粒通过LR重组反应将入门文库转换为三框表达文库,经测定平均滴度为1×105CFU/mL,文库总容量为1.2×106CFU,平均插入片段为1 017 bp,阳性重组率为100%.结果表明所构建的三框cDNA表达文库具有较高的重组率和较大的库容量,为进一步筛选鸡传染性法氏囊病病毒(IBDV)在法氏囊B淋巴细胞中的受体及研究细胞嗜性奠定了基础.     

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。     

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.     

Mechanism of Action of Probiotic Function of Lactobacilli

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.     

Evaluation of serum concentrations of biomarkers of skeletal metabolism and results of radiography as indicators of severity of osteochondrosis in foals

OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis.