细菌鞭毛蛋白免疫佐剂活性作用机制及应用研究进展

正鞭毛是位于细菌表面的一种长丝状附属物,由基体部(Basal body)、鞭毛钩(Hook)和鞭毛丝(Fila-ment)3部分组成,其中fliC是鞭毛蛋白编码基因的主要结构成分。鞭毛蛋白是一种重要的病原体相关分子模式(Pathogen-associated molecular patterns,PAMPs),能激活细胞表面Toll样受体5(Toll-like re-     

E.coli纤毛抗原K_(99)菌株电子显微镜观察试验

肠致病性埃希氏大肠杆菌(E.co1i)的粘附因子K_(99)抗原,是一种易热蛋白质,从形态上看是一种纤毛结构,这种纤毛可以粘附于小肠上皮细胞,使细菌在小肠中聚集产生肠毒素而致病。这种纤毛的致病作用越来越引起人们的重视,在兽医研究方面,现已发现猪的肠致病性大肠杆菌带有K_(88)、K_(99)和987P三种纤毛抗原,在引起新生仔猪腹泻     

论药效学的药理机制对提高药剂应用水平的作用(下)

4特异性作用机制的药剂 　　特异性作用机制的药剂具有如下特性： 　　(1)选择作用于动物体细胞或酶或其特定的部位 (靶细胞或靶分子 )；其作用与化学结构有关； 　　(2)通过特定的第二信使或效应系统引起药理反应； 　　(3)能产生特定的药效与临床效果，有明确的适应证和禁忌证； 　　(4)多数药物的反应浓度低 (剂量小 )而作用显著； 　　(5)多数都有相应的拮抗剂。 　　与受体发生作用的药物 [见 (上 )文 2]是典型的特异性作用机制的药剂，此外，还列出下列类型。 4.1影响细胞膜离子通道的药剂 　　根据细胞膜生理电位学说：细胞膜内外分…     

畜禽传染病及其传播途径

畜禽传染病是指某种病原微生物(细菌、病毒或其它微生物)侵入畜禽机体后,使机体低抗力减弱而引起的具有一定潜伏期、临床表现和传染性的疾病。 传染病与非传染病相比较,有三个特点: 一、致病因子是活的病原微生物,当这种微生物侵入易感畜禽体内后,能使机体出现固有的临床症     

大肠杆菌鞭毛研究进展

鞭毛是位于细菌表面的长螺旋形可旋转附属物,长约10μm,主要与细菌的运动有关。鞭毛的驱动力是许多细菌病原体的重要毒力特征,并且是建立感染所必需的。感染发生后,鞭毛有利于细菌到达侵入部位。大肠杆菌(Escherichia coli,E.coli)一般周身鞭毛,具有运动性。鞭毛蛋白,又称为H抗原,是大肠杆菌分类的重要表面抗原。本文对大肠杆菌鞭毛的结构、功能和H抗原分型作一简要综述,旨在为本领域的相关研究提供一定的理论基础和依据。     

补体C3b肽段的免疫功能

补体既是动物非特异性免疫系统的重要组成部分,又在特异性体液免疫中发挥重要作用,在细菌免疫过程中发挥主要作用。特异性的抗体与细菌结合后,可以出现凝集和鞭毛制动现象,但一般而言,对于细菌的活力只有微弱的影响,甚至没有影响,而细菌的清除主要是靠补体的溶菌作用或吞噬细胞的吞噬作用。C3b是补体激活过程中产生的重要片断,它是连接3 条补体激活途径的中心环节;由α、β两条肽链组成,两肽链间以二硫键相连;在α链的半胱氨酸和谷氨酸残基之间的分子内硫酯键,使之对病原微生物发挥调理作用;在动物体的多种细胞上都存在C3b受体,C3b 通过与其受体的相互作用而发挥免疫调节作用,例如巨噬细胞的免疫吞噬作用,红细胞的免疫黏附作用,巨噬细胞、树突状细胞、B细胞等的抗原提呈作用等。     

牛产肠毒素性大肠杆菌病的防治

<正>1发病原因和机制产肠毒素性大肠杆菌有两个毒力因子,既能吸附到肠上皮细胞黏膜表面,又能产生肠毒素,据此可以将它与非致病性大肠杆菌区分开。黏附是由一种被称之为菌毛的丝状结构蛋白介导的,这种丝状结构蛋白有时也被称为纤毛或黏附素,它能与肠上皮细胞膜上的特异性受体结合。与EPEC(肠致病性大肠杆菌)和EHEC(肠出血性大肠杆菌)能和肠上皮细胞的肠腔面紧密接触不同,菌毛介     

细菌鞭毛运动、黏附和免疫逃逸机制的研究进展

鞭毛是细菌表面重要的附属结构之一,很长一段时间以来被认为仅负责细菌的运动。然而随着对鞭毛的结构以及致病性深入研究发现,鞭毛的运动性能够促进细菌与宿主的相互作用,鞭毛介导的黏附在几种动植物病原体对宿主的定植过程中起很重要作用,而促进鞭毛结合到不同宿主组织的特异性互作机制至今仍不清楚。鞭毛素单体的保守区是机体先天性免疫应答的有效诱导剂,能够诱导机体发生免疫应答,然而细菌也进化出多重策略来逃避免疫识别。现对近年来细菌鞭毛在动植物宿主环境中的作用作一综述,为更全面认识和研究鞭毛提供参考。     

霉菌毒素对养猪生产的危害与防控技术

霉菌是丝状真菌,含有菌丝结构(丝状或线状)或者形成孢子体.真菌毒素是指存在于自然界的各种真菌所产生的有毒次生代谢产物.这些代谢产物可作为毒力因子,增加真菌的生存能力,增加植物致病性抑制细菌竞争或作为真菌物种间的化学信号.这些霉菌产生的毒素对人类、动物和农作物均具有较大的毒性作用,给农牧业生产造成了严重的危害.据联合国粮...     

细菌表面抗原单克隆抗体的应用研究近况

细菌表面抗原结构复杂,并与细菌的致病、免疫诊断、免疫治疗以及疫苗制备等密切相关。多年来,细菌的表面抗原结构一直是人们深入研究的重要课题。单克隆抗体(McAb)技术的问世,使人们在这一领域有许多重大发现,解决了不少过去无法解决的难题。现已制备出多种针对细菌表面抗原的McAb,除用于分析研究细菌表面抗原外,在其它方面的应用也取得好的结果。     

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.