重组绿脓杆菌外毒素A受体结构区蛋白的初步复性及细胞生物学？…

用逐步稀释透析法将将纯化的大肠杆菌表达的重组绿脓杆菌外毒素Ａ（ＰＥＡ）受体结合区蛋白初步复性,复性后的可溶性蛋白用于竞争抑制ＰＥＡ的细胞毒性实验。将１０μｇ／Ｌ的ＰＥＡ与其敏感细胞１．９２９共孵育,３６ｈ左右可见细胞发生病变死亡,而同时加入复性的重组ＰＥＡ受体结合区蛋白的培养细胞也与未加ＰＥＡ阴性对照培养细胞一样仍分裂增殖,这种ＰＥＡ细胞毒性抑制人作用可持续到所有培养细胞老化死亡,结果表明,重组Ｐ     

含绿脓杆菌外毒素A受体结合区重组蛋白的纯化

将表达含绿脓杆菌外毒素（ＰＥＡ）受体结合区基因的质粒ｐＥＴ－ＥＡＢ转化到大肠杆菌ＢＬ２１（ＤＥ３）中,经ＩＰＴＧ诱导表达了含ＰＥＡ受体结合区的重组蛋白（称ＰＥ３４）。ＰＥ３４主要以包涵体形式存在于大肠杆菌中,用溶菌酶－脱氧胆酸钠法结合超声波裂解法破碎细菌,离心制备包涵体。用２ｍｏｌ／Ｌ脲洗涤包涵体后,包涵体纯度可达７５％,在８ｍｏｌ／Ｌ脲存在条件下,ＳｅｐｈａｃｒｙｌＳ－２００凝胶滤过,ＤＥＡＥ－ＳｅｐｈａｒｏｓｅＦａｓｔＦｌｏｗ离子交换层析纯化,获得ＳＤＳ－ＰＡＧＥ１条带的ＰＥ３４,纯度达９５．８％,得率为２４．５％。     

绿脓杆菌外毒素A受体结合亚单位基因的克隆与表达

为防治绿脓杆菌感染造成的细胞坏死及多器官衰竭，本试验克隆了含绿脓杆菌外毒素Ａ（ＰＥＡ）结合亚单位（Ⅰ区）和部分跨膜亚单位（Ⅱ区）编码３０９个氨基酸的约１０００ｂｐ的基因片段，以正确阅读框架将该片段置于原核高效表达Ｔ７启动子下游，构建了高效表达质粒ｐＥＴ－ＥＡＢ。转化宿主菌ＢＬ２１（ＤＥ３）、ＨＭＳ１７４（ＤＥ３）、ＨＭ１７４（ＤＥ３）ｐｌｙｓＳ和ＢＬ２１（ＤＥ３）ｐｌｙｓＳ后，经ＩＰＴＧ诱导４ｈ，均表达了外源目的基因蛋白，其中ＢＬ２１（ＤＥ３）和ＢＬ２１（ＤＥ３）ｐｌｙｓＳ的表达量明显高于其他宿主菌。经ＳＤＳ－ＰＡＧＥ分析，外源蛋白分子量约３４０００，与ＰＥＡⅠ区和部分Ⅱ区基因所编码的蛋白理论估计值相符，命名为ＰＥ３４。凝胶薄层扫描显示，ＰＥ３４含量占菌体蛋白总量的５６％。Ｗｅｓｔｅｒｎ－ｂｌｏｔｉｎｇ检测证明ＰＥ３４为所需目的蛋白     

以包涵体形式表达的猪带绦虫六钩蚴重组原的复性与纯化

应用比浊法,可溶必蛋白百分比,夹心ＥＬＩＳＡ及变性与非变性ＳＤＳ－ＰＡＧＥ等方法来评价猪带绦虫六钩蚴重组抗原的不同复性条件。透析法复性,透析液为含２ｍｏｌ／Ｌ尿素,１６０℃ｍｏｌ／ＬＰＥＧ４０００,１．０ｍｍｏｌ／Ｌ－０．１ｍｍｏｌ／ＬＧＳＨ－ＧＳＳＧ的ＰＨ９．０的Ｔｒｉｓ－ＨＣｌ缓冲液,蛋白浓度为２－５ｍｇ＝ｍＬ,以静置缓慢透年为佳,上述条件任意缺一或快速透析,则免疫活性下降,二聚体,多聚体明显     

抗新城疫病毒糖蛋白单克隆抗体的研制及其特异性分析

应用纯化的新城疫病毒Ｆ４８Ｅ９株免疫ＢＡＬＢ／Ｃ小鼠，取脾细胞与ＳＰ２／Ｐ骨髓瘤细胞融合，经间接ＥＬＩＳＡ法检测筛选到４２株分泌抗ＨＤＶ单克隆抗体的杂交瘤细胞株。并对各株单克隆抗体的免疫球蛋白亚类，血凝抑制效价，溶血抑制效应ＥＬＩＳＡ效价及中和效价加 测定，结合单克隆抗体的Ｗｅｓｔｅｒｂ ｂｌｏｔ反应结果出抗ＮＤＶ ＨＮ蛋白１１株，抗Ｆ蛋白２０株。     

大肠杆菌肠毒素ST1-LTB融合基因的高效表达

用限制性核酸内切酶ＥｃｏＲⅠ和ＨｉｎｄⅢ双酶切含大肠杆菌肠毒素ＳＴ１—ＬＴＢ融合基因的质粒ｐＸＳＬＴ１,回收０８４ｋｂ的ＳＴ１—ＬＴＢ融合基因,再将载体ｐＥＴ—２８ｂ（＋）用ＥｃｏＲⅠ和ＨｉｎｄⅢ双酶切,然后将其与ＳＴ１—ＬＴＢ融合基因连接,转化至受体菌ＢＬ２１（ＤＥ３）中。经ＥｃｏＲⅠ、ＨｉｎｄⅢ、ＢａｍＨⅠ酶切反应鉴定重组子质粒,得到了理想重组质粒ｐＸＥＴＳＬＴ１。重组菌株ＢＬ２１（ＤＥ３）（ｐＸＥＴＳＬＴ１）经ＩＰＴＧ诱导后,其表达产物经ＳＤＳ—ＰＡＧＥ和ＥＬＩＳＡ检测,结果表明重组菌株可以高效表达ＳＴ１—ＬＴＢ融合蛋白,该融合蛋白占菌体总蛋白的３３２１％,而且无天然ＳＴ１生物毒性。     

人雄激素受体的雄激素结合区cDNA在E.coli中的高效表达

将编码人雄激素受体（ｈＡＲ）的雄素结合区（ＬＢＤ）的ｃＤＮＡ片段（１００５ｂｐ）克隆到由Ｐ１启动子控制的硫氧还蛋白表达载体ｐＴｒｘＦｕｓ上,构建了表达质粒ｐＴｒｘＡＲ,并转化到大肠杆菌Ｇ１７２４中,经色氨酸诱导表达后,ＳＤＳ－ＰＡＧＥ分析,可观察到一高效表达的融合蛋白产物,此融合蛋白 分子了量与理论值相吻合,氨基酸组分分析证明了ＬＢＤ目的基因的表达。     

类志贺氏菌毒素Ⅱ型变异体B亚单位基因的表达与鉴定

将由 Ｐ Ｃ Ｒ 扩增并克隆在ｐ Ｕ Ｃ１８ 质粒载体中的ｓｌｔⅡｅ Ｂ基因切出,并按预定的阅读框架插入表达性质粒载体 ｐ Ｇ Ｅ Ｘ６ｐ１ 中的谷胱苷肽转移酶（ Ｇ Ｓ Ｔ）基因的下游。重组质粒 ｐｐｐｓｌｔⅡｅ Ｂ在大肠杆菌 Ｂ Ｌ２１ 中以融合蛋白的形式表达 Ｓ Ｌ ＴⅡｅ Ｂ蛋白（命名为 Ｇ Ｓ Ｔ Ｓ Ｌ ＴⅡｅ Ｂ）,即 Ｓ Ｌ ＴⅡｅ Ｂ蛋白（７５６８ｋ Ｄ）与谷胱苷肽转移酶（２７３３５ｋ Ｄ）相连组成分子量为 ３４８８５ｋ Ｄ 的融合蛋白。通过对重组大肠杆菌 Ｐ Ｐ Ｓ Ｌ ＴⅡｅ Ｂ的菌体裂解物的 Ｓ Ｄ Ｓ Ｐ Ａ Ｇ Ｅ 电泳分析,以及根据抗原抗体结合反应的免疫学特性,通过 Ｗｅｓｔｅｒｎｂｌｏｔ 鉴定,重组大肠杆菌 Ｐ Ｐ Ｓ Ｌ ＴⅡｅ Ｂ（含有重组质粒 ｐｐｓｌｔⅡｅ Ｂ的大肠杆菌 Ｂ Ｌ２１）可以大量表达融合蛋白形式的 Ｓ Ｌ ＴⅡｅ Ｂ。根据 Ｇ Ｓ Ｔ 可与其底物谷胱苷肽结合的特性,用谷胱苷肽结合的 Ｓｅｐｈａｒｏｓｅ ４ Ｂ制备的亲和凝胶纯化表达产物,纯化的表达产物经 Ｓ Ｄ Ｓ Ｐ Ａ Ｇ Ｅ,可以鉴定到分子量约为 ３５ｋ Ｄ 的蛋白条带,这与融合蛋白形式的 Ｓ Ｌ ＴⅡｅ Ｂ分子量（３４８８５ｋ Ｄ）相当。     

抗新城疫病毒糖蛋白单克隆抗体的研制及其特异性分析

应用纯化的新城疫病毒（ＮＤＶ）Ｆ４８Ｅ９株免疫ＢＡＬＢ／Ｃ小鼠，取脾细胞与ＳＰ２／０骨髓瘤细胞融合，经间接ＥＬＩＳＡ法检测筛选到４２株分泌抗ＮＤＶ单克隆抗体的杂交瘤细胞株。并对各株单克隆抗体的免疫球蛋白亚类、血凝抑制效价（ＨＩ）、溶血抑制效价（ＨＬＩ）、ＥＬＩＳＡ效价及中和效价加进行了测定，结合单克隆抗体的Ｗｅｓｔｅｒｎｂｌｏｔ反应结果鉴定出抗ＮＤＶＨＮ蛋白１１株，抗Ｆ蛋白２０株     

表达大肠杆菌肠毒素ST1-LTB融合蛋白双价基因工程菌株的构建

重组菌株ＢＬ２１（ＤＥ３）（ｐＸＥＴＳＬＴ１）经ＩＰＴＧ诱导后,其表达产物经ＳＤＳ－ＰＡＧＥ和ＥＬＩＳＡ检测,结果表明重组菌株可以高效表达大肠杆菌肠毒素ＳＴ１－ＬＴＢ 融合蛋白,该融合蛋白占菌体总蛋白的３３．２１％ ,而且已失去天然ＳＴ１肠毒素生物毒性。用从ＩＰＴＧ 诱导的工程菌中提取的包涵体或经甲醛灭活的工程菌制成抗原免疫小鼠,结果免疫小鼠至少能抵抗１．５ＭＬＤ 的大肠杆菌强毒株Ｃ８３９０２（Ｋ８８ａｃ,ＳＴ＋ ,ＬＴ＋ ）的攻击。用提取的包涵体免疫家兔后,采集的血清能够中和天然ＳＴ１肠毒素的毒性。这表明构建的工程菌株ＢＬ２１（ＤＥ３）（ｐＸＥＴＳＬＴ１）可以作为预防幼畜大肠杆菌性腹泻基因工程菌苗的候选株     

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。     

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。     

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.     

獭兔睾丸的组织学观察

家兔作为一种实验动物 ,推动了繁殖技术的发展。本试验通过对不同年龄公獭兔的睾丸进行组织学观察、测定 ,研究精子的发生规律 ,为系统地进行繁殖生理工作提供依据。1　材料与方法选 60日龄、75日龄、90日龄 3个年龄公獭兔各5只 ,用外科手术法摘取两侧睾丸 ,放入 Bouin氏液中固定 ,二甲苯透明 ,石蜡包埋 ,切成 5～ 8μm切片 ,H.E.染色。在显微镜下观察 ,并进行定量组织学指标测定及差异性比较。2　结果和讨论2 .1　睾丸定量组织学指标的测定结果　见表 1。表 1　獭兔睾丸定量组织学指标　　　μm,个 /精细管60日龄 75日龄 90日龄曲细精管…     

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。     

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.