IL-10对感染口蹄疫病毒的树突状细胞的影响

树突状细胞(dendritic cells,DC)是机体中重要的抗原递呈细胞,在病毒感染机体后的免疫调节过程中具有重要作用。为研究调节IL-10的分泌是否会影响DC感染病毒后的免疫反应,本研究用FMDV感染DC后发现,IL-10的分泌量可以影响DC在免疫过程中各种细胞因子的表达,故认为IL-10在口蹄疫病毒感染过程中对机体的免疫调节具有重要的影响。     

口蹄疫病毒利用自身蛋白逃逸宿主天然免疫应答的研究进展

口蹄疫（foot-and-mouth disease,FMD）是由口蹄疫病毒（foot-and-mouth disease virus,FMDV）感染偶蹄兽所引起的一种急性、热性、高度接触性传染病,FMDV有7个血清型,加之病毒传播迅速,严重影响畜牧业的发展。FMDV为小RNA病毒科、口蹄疫病毒属的唯一成员,其基因组编码4种结构蛋白和10种非结构蛋白。FMDV感染宿主后利用自身蛋白通过多种途径和方式来影响宿主天然免疫应答,从而有利于FMDV复制的微环境。这些策略包括FMDV参与细胞自噬、内质网应激和应激颗粒形成的细胞过程,破坏多种宿主蛋白的功能,如劫持、裂解宿主蛋白或干扰宿主蛋白的表达、去除宿主蛋白的泛素化以及抑制宿主蛋白的磷酸化。这些逃避天然免疫的策略也是目前研究的热点。基于现有的研究结果,作者总结了近几年FMDV蛋白在抑制宿主天然免疫方面的研究进展,以期为FMDV的研究与防控提供参考。     

逆转录病毒载体介导的口蹄疫病毒衣壳前体基因和绿色荧光蛋白基因在BHK-21细胞中的表达

为建立逆转录病毒载体介导的口蹄疫病毒衣壳前体蛋白哺乳动物细胞表达体系,将口蹄疫病毒（FMDV）衣壳前体基因（P1）和绿色荧光蛋白基因（EGFP）依次插入逆转录病毒载体pBABEpuro构建重组逆转录病毒载体pBABEpuro-P1-2A-EGFP。将重组逆转录病毒载体和pVSV-G质粒载体共转染GP2-293包装细胞,用产生的重组逆转录病毒感染幼仓鼠肾细胞（BHK-21）。荧光显微镜下观察绿色荧光蛋白的表达,用嘌呤霉素筛选抗性细胞,间接免疫荧光方法检测细胞中FMDV衣壳前体蛋白的表达。结果表明,重组逆转录病毒载体pBABEpuro-P1-2A-EGFP构建正确,绿色荧光蛋白和FMDV衣壳前体蛋白在细胞中能稳定表达。FMDV衣壳前体蛋白基因细胞表达体系的成功建立为进一步开展口蹄疫亚单位疫苗的研制奠定了基础。     

Gα12蛋白抑制口蹄疫病毒在PK-15细胞上复制

鸟嘌呤核苷酸结合蛋白Gα12参与多种细胞反应的调节,但是在口蹄疫病毒（foot-and-mouth disease virus,FMDV）方面的研究较少。本研究中,用FMDV感染PK-15细胞,发现Gα12的mRNA和蛋白水平都有所上调,预示Gα12可能与FMDV复制存在某种联系,需要进一步研究Gα12蛋白对FMDV在PK-15细胞上复制的影响。为此,在过表达Gα12和干扰Gα12表达的情况下,通过实时荧光定量、Western blot和TCID₅₀检测Gα12对FMDV复制的影响。结果表明,过表达Gα12后,FMDV的mRNA水平、蛋白水平和病毒滴度都有所降低,然而,下调Gα12后,FMDV的复制呈相反的趋势,说明Gα12可以抑制FMDV在PK-15细胞上的复制。本研究首次发现Gα12具有抑制口蹄疫病毒复制的作用,为抗FMDV的研究提供了新思路和理论基础,对FMDV相关研究具有重要意义。     

TPL2促进口蹄疫病毒在BHK-21细胞复制

为研究肿瘤进行性位点2(TPL2)在仓鼠肾细胞(BHK-21)中对口蹄疫病毒(FMDV)复制的影响,使用FMDV感染BHK-21细胞,通过qRT-PCR技术检测FMDV感染对内源性TPL2转录水平的影响;根据GenBank公布的TPL2基因序列(NM007746.2)设计构建TPL2的真核表达质粒以及设计并合成宿主TPL2的RNAi序列,利用脂质体方法转染BHK-21细胞,通过qRT-PCR和Western blotting技术分析TPL2在BHK-21细胞过表达和干扰对FMDV复制的影响。结果表明,FMDV感染BHK-21细胞后,TPL2转录水平显著上调;过表达TPL2能够促进FMDV在BHK-21细胞中复制,而下调表达内源性TPL2后FMDV的复制受到抑制,表明TPL2促进FMDV在BHK-21细胞中进行复制,本结果进一步拓展了我们对FMDV与天然免疫机制之间关系的认识,同时为TPL2的相关研究积累了科学资料。     

猪黑色素瘤分化相关基因5(MDA5)对口蹄疫病毒感染宿主的影响

为研究猪黑色素瘤分化相关基因5(MDA5)对口蹄疫病毒(FMDV)感染宿主细胞的影响,本研究通过构建含有猪MDA5基因的表达质粒,转染细胞后接种FMDV,检测猪MDA5对FMDV的感染能力的影响。结果显示,重组质粒pCMV-Myc-pMDA5能在PK-15细胞中获得表达,并且上调MDA5基因能够一定程度地抑制FMDV感染。本试验结果表明,MDA5具有一定的抗病毒作用,为研究FMDV逃逸宿主天然免疫的机制奠定了一定基础。     

Asia1型FMDV感染BHK-21细胞差异蛋白质点2-DE分析

为研究Asia 1型口蹄疫病毒(FMDV)感染BHK-21细胞后蛋白质组的变化及差异,将FMDV接种于培养的单层BHK-21细胞,同时设未接毒的BHK-21细胞作对照组.待细胞病变后分别提取2组细胞总蛋白借助2-DE技术及PDQuest8.0软件进行细胞蛋白质组二维电泳图谱差异性分析.结果显示感染组有1 457个可见蛋白质点,而对照组可见的蛋白质点为1 427个.感染组蛋白点的表达量与对照组相比,二者具有统计学差异(P<0.05)的蛋白质点472个,其中表达上调251个点,表达下调221个点,新合成蛋白点30个.结果表明FMDV感染BHK-21细胞后弓l起了细胞蛋白质组表达模式的改变,这种变化是病毒与细胞相互作用的结果.本研究首次利用蛋白质组学技术研究Asia 1型FMDV感染BHK-21细胞后蛋白质组学差异,有助于深入研究Asia 1型FMDV和BHK-21细胞相互作用的分子机制.     

PK-15细胞的TPL2基因敲除有利于口蹄疫病毒和塞内卡病毒复制

旨在构建TPL2（MAP3K8/COT）基因敲除PK-15细胞系PK-15-TPL2^-/-,评估该基因敲除前后对口蹄疫病毒（FMDV）和塞内卡病毒（SVA）复制的影响及产生影响的原因,为研究TPL2在病毒感染过程中的作用机制提供良好的生物材料,也为疫苗生产过程中进一步提升FMDV和SVA产量指明方向。筛选2条针对TPL2基因的单向导RNA（sg RNA）,合成sg RNA并将其插入到含有GFP标签的慢病毒表达载体,构建sg RNA/Cas9慢病毒表达质粒,包装慢病毒并感染PK-15细胞,通过流式细胞仪分选出已被转入sg RNA的单细胞。通过测序确认细胞系中TPL2的DNA序列,通过蛋白质印迹（Western blot）方法检测细胞系中TPL2表达情况。使用FMDV和SVA感染构建好的细胞系,利用IFA、RT-qPCR、Western blot和TCID₅₀评估FMDV和SVA在PK-15-TPL2^-/-细胞中的复制水平,在此基础上通过测定干扰素（IFN）和IFN刺激基因（ISG）的mRNA表达水平,研究了FMDV或SVA感染的PK-15-TPL2^-/-细胞中干扰素途径的激活状态。TPL2基因敲除PK-15细胞系中TPL2基因发生了碱基插入突变和碱基缺失突变,构建的细胞系中均未检测到TPL2蛋白质表达。测定并比较了FMDV和SVA感染的PK-15和PK-15-TPL2^-/-细胞中病毒含量,表明TPL2基因敲除显著促进了FMDV和SVA的复制。同时,RT-qPCR进一步表明与FMDV和SVA感染期间的PK-15细胞相比,PK-15-TPL2^-/-细胞中IFN-α、IFN-β、IFN-γ、ISG15、ISG54和ISG56的mRNA表达明显降低。综上所述,本研究成功构建了TPL2基因敲除的PK-15细胞系,与对照细胞相比,TPL2基因的敲除更利于FMDV和SVA的复制,这可能与IFN-α、IFN-β、IFN-γ、ISG15、ISG54和ISG56表达的抑制有关。本研究提示CRISPR/Cas9基因编辑技术可以作为在动物和疫苗开发过程中编辑细胞系以提高病毒产量的有效工具,本结果为进一步提升FMDV和SVA产量指明了方向,也为研究TPL2在病毒感染过程中的作用机制提供了良好的生物材料。     

口蹄疫病毒突破宿主细胞天然免疫应答的机制

口蹄疫病毒(FMDV)感染宿主必须突破天然免疫应答,细胞天然免疫应答是宿主天然免疫应答最关键的组成部分。FMDV只有突破宿主细胞天然免疫才能在细胞内生长、繁殖和传播,为达到这一目的要利用多种途径来抗衡甚至破坏宿主细胞天然免疫应答。然而FMDV突破宿主细胞天然免疫应答的机制至今尚不十分清楚,深入了解FMDV突破宿主细胞天然免疫应答机制,有助于人们进一步认知FMDV致病机理,开发新型疫苗和生物治疗药物以应对口蹄疫的暴发和流行。本文从FMDV感染后宿主细胞的转录和翻译系统,病毒抗原性多肽的递呈、天然免疫细胞功能损伤和免疫病理作用四个方面对FMDV突破宿主细胞天然免疫的机制作以综述。     

口蹄疫病毒VP2基因的真核表达及其产物抗原性的检测

利用PCR技术，扩增出口蹄疫病毒（FMDV）VP2基因，并克隆到杆状病毒转移载体pBlueBacHis2A上。用重组质粒pB-VP2与重组病毒同时转染sf9昆虫细胞，获得了重组病毒。经过蚀斑筛选纯化后，感染sf9细胞，表达VP2融合蛋白，分子质量为33ku左右。以牛抗O型FMDV血清为第一抗体，通过Western-blotting和Dot-ELISA鉴定，说明VP2基因在真核表达系统中获得正确表达，且可以与牛抗。型FMDV血清发生特异性反应。     

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.