阳离子脂质体的制备及其与禽流感病毒HA基因作用的研究

用超声波法制备了ＤＣ－ｃｈｏｌ阳离子脂质体,研究了阳离子脂质体与禽流感病毒保护性抗原血凝素基因重组质粒ｐＳＶＨ７复合物的特性。电子显微镜观察表明,阳离子脂质体与ｐＳＶＨ７形成复合物后,脂质体发生聚集,膜融合,脂质体直径变大,并出现了多层结构脂质体;通过检测脂质体在２４８ｎｍ处的吸光度变化,研究了脂质体与ｐＳＶＨ７质粒复合物形成及膜融合的动力学过程,脂质体ＤＮＡ复合物是在最初１－１５ｍｉｎ内形成的,     

H_5和H_7亚型禽流感病毒HA基因的RT-PCR扩增及克隆

采用反转录－聚合酶链反应（ＲＴ－ＰＣＲ）方法，以自行设计的Ｈ７和Н５亚型禽流感病毒血凝素（ＨＡ）基因特异的两对引物，分别扩增了禽流感病毒Ａ／ＡｆｒｉｃａｎＳｔａｒｌｉｎｇ／９８３／７９（Ｈ７Ｎ１）株和Ｇ株（广东鹅体分离株，Ｈ５Ｎ１）约１．７ｋｂ的ＨＡ全基因ｃＤＮＡ。将所扩增的两个基因ｃＤＮＡ未端经Ｔ４ＤＮＡ聚合酶修饰后分别插入ｐＵＣ１８和ｐＢｌｕｅｓｃｒｉｐｔ质粒中，得到了两个基因的重组质粒。本研究为国内禽流感病毒分子生物学研究奠定了基础     

禽流感病毒血凝素基因的克隆及其DNA疫苗的免疫原性

禽流感病毒（ＡＩＶ）的表面结构蛋白血凝素（ＨＡ）是其主要保护性抗原。本研究参考已发表的Ｈ７亚型ＡＩＶ的ＨＡ基因序列，设计合成了１对Ｈ７ＨＡ特异引物，以ＡＩＶＡ／Ａｆｒｉ．Ｓｔａｒ．／Ｅｎｇ－Ｑ／９８３／７９／（Ｈ７Ｎ１）（Ａ／Ａｆｒｉ．Ｓｔａｒ．／Ｅｎｇ）核酸为模板，通过ＲＴ－ＰＣＲ扩增出１条１．７ｋｂｃＤＮＡ片段。将这一片段定向克隆到ｐＵＣ１８中，对其５′端及３′端部分序列测定后，确证其为ＨＡｃＤＮＡ。将ＨＡ基因置于ＳＶ４０启动子和增强子下游，构建了这一基因的真核表达质粒ｐＳＶＨ７。以此质粒１００μｇ肌肉注射免疫３周龄ＳＰＦ鸡６只，４周后以１００倍鸡胚感染剂量（ＥＩＤ）的ＨＡ基因同源病毒对所有鸡进行攻毒，１周后以棉拭子进行泄殖腔病毒分离；免疫后１～６周每周对所有鸡翅静脉采血，分离血清，检测ＨＩ抗体。结果，１００μｇ免疫组鸡病毒分离数为０／６，对照组为６／６；攻毒后１周免疫组鸡ＨＩ效价为１∶３２～１∶６４，对照组为１∶４～１∶１６。表明所构建的ＨＡ基因表达质粒可作为基因疫苗诱导鸡产生免疫保护反应。     

流感病毒血凝素基因在昆虫细胞中的表达

应用ＲＴ－ＰＣＲ方法扩增了禽流感病毒Ａ／Ｇｏｏｓｅ／Ｇｕａｎｇｄｏｎｇ／１／９６（Ｈ５Ｎ１）１．７ｋｂ的ＨＡ基因,将其克隆到ｐＵＣ１９的ＢａｍＨＩ位点,筛选到阳性重组子 ｐＵＣＨ５。然后将 ＨＡ基因亚克隆到杆状病毒转移载体 ｐＢｌｕｅＢａｃＨｉｓＢ,筛选到重组转移载体ｐＢａｃＨ５。经过序列分析证明阅读框架正确后,在脂质体转染试剂介导下,ｐＢａｃＨ５与线性化的杆状病毒 ＤＮＡ（Ｂａｃ－Ｎ－Ｂｌｕｅ ＤＮＡ）共转染Ｓｆ９昆虫细胞。重组杆状病毒经三轮蚀斑纯化,获得纯化的重组杆状病毒ｒＢａｃＨ５。提取重组杆状病毒ＤＮＡ经ＰＣＲ扩增证明目的基因片段插入到杆状病毒基因组中。间接免疫荧光染色试验、血凝试验和 Ｗｅｓｔｅｒｎ ｂｌｏｔ试验结果表明 ＨＡ基因在重组杆状病毒感染的Ｓｆ９细胞表面获得表达。重组杆状病毒表达的ＨＡ蛋白能够凝集公鸡红细胞,血凝价１２８０－２５６０ＨＡＵ／ｍｌ。ＨＡ蛋白在杆状病毒表达系统的成功表达,为禽流感亚单位疫苗的研制奠定了基础。     

组织型纤溶酶原激活剂基因在小鼠体内的表达

将组织型纤溶酶原激活剂（ｔ－ＰＡ）基因ｃＤＮＡ经多次亚克隆插入到真核表达载体ｐＳＶＬ的ＳＶ４０启动子和ｐｃＤＮＡ３的ＣＭＶ启动子下游,构建了重组质粒ｐＳＶＬ－ｔＰＡ和ｐｃＤＮＡ３－ｔＰＡ。分别将这２种重组质粒直接注射于小鼠骨骼肌,观察了ｔ－ＰＡ基因在小鼠体内的表达情况。体外凝血试验结果显示,注射重组质粒ＤＮＡ后,第５天凝血时间有所延长,第１５～２０天达到高峰,小鼠体外凝血时间平均延长７ｍｉｎ左右,延长时间与基因注射量呈明显的正相关。     

HIV—2gag基因在重组痘苗病毒中的表达

以痘苗病毒ＨＡ基因为侧翼，将ＨＩＶ－２ｇａｇ基因部分序列（简称Ｇ１）和全部序列（简称Ｇ２）分别插入牛痘病毒Ａ型包涵体（ＡＴＩ）和串联１０个（与ＨＡ基因反向）或１６个（与ＨＡ基因同向）痘苗病毒Ｐ７．５组成的复合型启动子下游，构建了４个重组痘苗病毒表达载体质粒。经脂质体转染、鸡红细胞吸附试验筛选和免疫荧光鉴定，获得４株能稳定表达目的蛋白的重组痘苗病毒。实验结果表明，以ＨＡ基因为侧翼构建重组病毒的重组率约为０．１％，阳性重组率为２５％～１００％。实验中还发现，以ＨＡ基因为侧翼的重组痘苗病毒能够引起细胞融合，其可作为筛选重组痘苗病毒的另一种标志。Ｗｅｓｔｅｒｎｂｌｏｔ结果表明，表达的Ｇａｇ蛋白能被ＨＩＶ－２血清中的特异性抗体所识别，并能诱导小鼠产生抗ＨＩＶ－２Ｇａｇ抗体。     

组织型纤溶酶原激活剂cDNA在BHK21细胞中的表达

将组织型纤溶酶原激活剂（ｔ－ＰＡ）基因ｃＤＮＡ经多次亚克隆插入到真核表达载体ｐＳＶＬ的ＳＶ４０启动子和ｐｃＤＮＡ３的ＣＭＶ启动子下游,构建了重组表达质粒ｐＳＶＬ－ｔＰＡ和ｐｃＤＮＡ３－ｔＰＡ。分别将这２种表达质粒以脂质体载体法转染ＢＨＫ２１细胞,ＥＬＩＳＡ检测结果表明,ｐＳＶＬ－ｔＰＡ和ｐｃＤＮＡ３－ｔＰＡ在哺乳动物细胞中能够表达,７２ｈ表达量分别是５２．８μｇ／Ｌ和７０．４μｇ／Ｌ。     

禽流感病毒NP cDNA反义逆转录病毒载体的构建及重组病毒的鉴定

根据反义ＲＮＡ作用原理,以禽流感病毒（ＡＩＶ）Ｈ１４Ｎ５　ｃＤＮＡ全长及５’端２３５个ｂｐ为目的基因,反向插入反转录病毒载体 ｐＬＸＳＮ中,命名为 ｐＬＸＳＮ－ＮＰ及 ｐＬＸＳＮ－ＮＰ,用脂质体包裹重组质粒转染包装细胞 ＰＡ３１７,Ｇ４１８筛选抗性克性,扩增单个克隆后提取包装细胞上清的病毒ＲＮＡ（ｖＲＮＡ）,以巢式ＰＣＲ方法检测,以及用包装细胞上清（重组病毒）感染滴定细胞系ＮＩＨ３Ｔ３,表明已筛选出产毒的的克隆细胞质,得到重组逆转录病毒,为反义ＲＮＡ抑制禽流感病毒复制的实验研究奠定了物质基础。     

鸡痘病毒282E4株Bam HI Fa,Fb,Fc片段非必需区筛选与序列分析

将亚克隆获得的分别含有鸡痘病毒（ Ｆ Ｐ Ｖ） Ｂａｍ Ｈ Ｉ相应片段的 ｐ Ｕ Ｆａ、ｐ Ｕ Ｆｃ 和 ｐ Ｕ Ｆｄ ３ 个质粒的单酶切位点,插入 Ｐ１１ Ｐ７．５ Ｌａｃ Ｚ报告基因盒,构建成 ｐ Ｕ Ｆａ１、ｐ Ｕ Ｆｃ１ 和 ｐ Ｕ Ｆｄ１ ３ 个重组载体质粒,在脂质体存在条件下,同 Ｆ Ｐ Ｖ 共同转染鸡胚成纤维细胞（ Ｃ Ｅ Ｆ）,９６ ｈ 后在 Ｘｇａ１ 存在条件下挑选蓝色重组病毒空斑,经３ 次空斑纯化和传代,获得 １ 株可稳定表达 β半乳糖苷酶的重组病毒,并对该重组用质粒作了序列分析。     

伪狂犬病病毒Fa株gI和gp63基因缺失株的构建

用限制性核酸内切酶ＮｃｏＩ消化含有伪狂犬病病毒（ＰＲＶ）Ｆａ侏ＢａｍＨＩ－７片段的质粒ＰＰＢ７，以低融点琼脂糖回收目的片段，经连接并转化Ｅ．ｃｏｌｉ ＤＨ５ｄ，获得缺失３ｇＩ和部分ｇｐ６３基因的重组质粒ＰＰＢ７－１。将ＰＲＶ Ｆａ与ＰＰＢ７－１ ＤＮＡ共同转染ＰＫ１５单层细胞，待出现５０％以上细胞病变时收获病毒，并以蚀斑法得到纯化重组病毒株，命名为ＰＦＤＩ／Ｄ６３。小鼠试验证实缺失株对小鼠具有一定     

Pharmacokinetics of liposomal encapsulated buprenorphine suspension following subcutaneous administration to cats

We investigated the effects of liposome encapsulation at prolonging the systemic exposure of buprenorphine following subcutaneous administration in cats. Seven healthy male cats were dosed intravenously with 0.02 mg/kg buprenorphine solution (STD‐BUP), followed 14 days later by a subcutaneous injection of 0.2 mg/kg buprenorphine as a liposomal suspension (SUS‐BUP) containing drug molecules both in liposomes and the suspending vehicle. Buprenorphine time plasma concentration data for both dosing routes were analyzed simultaneously with four compartmental models. Goodness of fit was assessed both graphically and with the Akaike information criterion. The time‐course of intravenous STD‐BUP was biphasic, with a 4.39 h average terminal half‐life. The subcutaneous SUS‐BUP produced plasma buprenorphine concentrations above 0.5 μg/L for more than 96 h, with three distinct peaks in the first 15 h. The model with best fit comprised a central and a peripheral compartment, plus three subcutaneous absorption compartments: one of dissolved drug molecules that were absorbed through a first‐order process, and two of liposome‐encapsulated drug molecules that were transferred to the solution compartment through separate zero‐order processes. Liposomes effectively prolonged the systemic exposure of buprenorphine in cats.     

CTAB脂质体介导鸡新城疫病毒核酸免疫研究

用CTAB／DOPE脂质体包裹新城疫病毒血凝素神经氨酸酶（HN）基因的真核表达质粒pcHNM免疫5周龄仔鸡，1周后免疫鸡血清中的特异性HI抗体开始升高，至第6周空白对照组抗体2．06，裸DNA免疫鸡4．09，脂质体DNA免疫组为5．20；此时用新城疫强毒F48E9攻击，未免疫组鸡的存活率为27．28％，裸DNA免疫组81．82％，CTAB脂质体DNA免疫组100．00％，表明该质粒DNA被脂质体包裹后，不仅增加了动物的特异性抗体产生能力，而且增加了动物对新城疫强毒的抵抗力。     

吡喹酮脂质体冻干剂的制备及质量评估

制备了吡喹酮脂质体冻干剂,并对其质量进行评估。采用薄膜-超声法制备吡喹酮脂质体,结合冷冻干燥技术制备吡喹酮脂质体冻干剂,建立HPLC法测定吡喹酮脂质体的包封率,并研究其稳定性。优化后的脂质体冻干剂包封率在70％以上,粒径范围220～310nm,电镜结果显示,脂质体外观圆整而且均匀。本法制备的吡喹酮脂质体冻干剂质量稳定,且建立的包封率测定方法稳定可靠。     

Preparation and pharmacokinetics of ceftiofur sodium liposomes in cows

Liu, S., Guo, D., Guo, Y., Zhou, W. Preparation and pharmacokinetics of ceftiofur sodium liposomes in cows. J. vet. Pharmacol. Therap. 34 , 35–41. The objective of this study was to prepare ceftiofur sodium liposomes and assess their physical properties, stability, antibacterial effects, and pharmacokinetics. These liposomes appeared as a milky, light yellow suspension with encapsulation efficiency at 57.2 ± 1.17%, and there were no significant changes in all estimated indexes at 4 °C for 90 days. The minimum inhibitory concentrations of liposomes were all 1/4th that of ceftiofur sodium against Streptococcus suis, Staphylococcus aureus, Escherichia coli, and Salmonella enteritidis. Six healthy, adult cows in two treatment groups were dosed intravenously with ceftiofur sodium liposomes and ceftiofur sodium, serial blood samples collected, and plasma concentrations determined by high performance liquid chromatography. Intravenous plasma concentration profiles of liposomes best fit a two‐compartment model and the elimination half‐life was 2.11 times that of ceftiofur sodium. Thus, this liposome preparation provided therapeutically effective plasma concentrations for a longer duration than with the drug alone, making it more effective and convenient for use in treating bovine mastitis that requires long duration maintenance of therapeutic plasma concentrations.     

三种抗原检测H1N1猪流感病毒抗体的比较

本研究采用昆虫杆状病毒表达系统制备了H1N1亚型猪流感病毒的HA蛋白、类病毒脂质体、病毒样颗粒,分别作为抗原进行包被,采用间接酶联免疫吸附实验（ELISA）检测H1N1猪流感病毒抗体.特异性实验结果表明,单独表达的HA蛋白和类病毒脂质体特异性良好,但是病毒样颗粒不能区分不同亚型的流感病毒;敏感性实验结果表明,类病毒脂质体作为抗原的敏感性最好;重复性实验结果表明,三种抗原的重复性好,ELISA实验的批间和批内变异系数均小于10％;稳定性实验结果表明,在4℃可至少稳定保存1年.综上所述,类病毒脂质体有较高的免疫反应性,与灭活全病毒相比有更好的安全性,在抗体水平测定方面有较好的应用前景.     

Efficient Transgene Expression in IVF and Parthenogenetic Bovine Embryos by Intracytoplasmic Injection of DNA–Liposome Complexes

Transgenic animals constitute an important tool with many biotechnological applications. Although there have been advances in this field, we propose a novel method that may greatly increase the efficiency of transgenic animal production and thereby its application. This new technique consists of intracytoplasmic injection of liposomes, in bovine oocytes and zygotes, to introduce exogenous DNA. In the first experiment, we evaluated embryo development and EGFP expression in In Vitro Fertilization (IVF) embryos injected with different concentrations of exogenous DNA–liposome complexes (0.5, 5, 50, 500 ng pCX‐EGFP/μl). The highest EGFP‐embryos rates were obtained using 500 ng pCX‐EGFP/μl. In the second experiment, we evaluated embryo development and EGFP expression following the injection of DNA–liposome complexes into pre‐fertilized oocytes and presumptive zygotes, 16 and 24 h post‐fertilization. Approximately 70% of the cleaved embryos and 50% of the blastocysts expressed EGFP, when egfp–liposome was injected 16 h post‐fertilization. The percentages of positive embryos for the 24‐h post‐fertilization and pre‐fertilization groups were 30.1 and 6.3, respectively. Blastocysts that developed from injected zygotes were analysed by PCR, confirming the presence of transgene in all embryos. Finally, we examined the embryo development and EGFP expression of parthenogenetic embryos that resulted from the injection of egfp–liposome complexes into pre‐activated oocytes, and 3 and 11 h post‐activated oocytes. The group with the highest expression rate (48.4%) was the one injected 3 h post‐activation. In summary, this study reports the efficient, reproducible and fast production of IVF and parthenogenetic embryos expressing EGFP, by the intracytoplasmic injection of liposomes to introduce the foreign DNA.     

Further studies of Mycoplasma gallisepticum serum plate agglutination antigen grown in medium with artificial liposomes substituting for serum

Frey's medium supplemented with artificial liposomes substituting for serum was evaluated for Mycoplasma gallisepticum (MG) serum plate agglutination (SPA) antigen. Antigens prepared in batch (static) culture were compared with antigens grown in a fermenter. All batch-grown MG liposome antigens were highly sensitive, specific, and resulted in a greater yield compared with fermenter-grown liposome antigens. Compared with antigens prepared in Frey's medium with 12% swine serum (regular FMS) or with commercial SPA antigens, liposome antigens had a higher degree of specificity; however, they were similar in sensitivity and antigen yield. The only growth parameter to affect the yield per liter of batch-grown liposome antigen was the concentration of liposomes in the growth medium. The reduced yield and sensitivity of antigens grown in a fermenter may have been due to autoclaving the medium instead of sterilizing by filtration. There was no obvious difference between patterns of serum-medium-grown, liposome-medium-grown, or commercial SPA antigens upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis.     

家蚕卵壳蛋白的紫外光谱性质

首次研究了家蚕卵壳蛋白的紫外光潜性质。结果表明,家蚕卵壳蛋白具有两个吸收峰区,除了在270—310nm处由生色氨基酸残基贡献的吸收峰区而外,其在220—260nm处的巨大紫外吸收峰区的物理意义,迄今未见报道。本试验利用DTT和EDTANa_2分别处理该卵壳蛋白后,前者使该紫外吸收峰完全消失,后者使其大部分消失,并皆呈现紫外差光谱峰。这表明双硫键和二价金属桥键是维系家蚕卵壳蛋白高级结构的重要结构力,並表明家蚕卵壳蛋白在220—260nm处的巨大紫外吸收峰是其高级结构的贡献。     

阿莫西林脂质体的制备及质量评价

采用薄膜分散法制备阿莫西林脂质体,以粒径和包封率为指标评价其质量.前期以正交设计优化筛选出最佳制备工艺,以最优工艺制备阿莫西林脂质体,测定其平均粒径和包封率.实验所制得的脂质体的平均粒径为114.6 nm,包封率为64.89％.结果表明,采用薄膜分散法制备阿莫西林脂质体的方法可行,阿莫西林脂质体的制备为兽药新剂型的研究与应用提供了有价值的参考.     

基于HPLC法测定五氯柳胺阿苯达唑复方混悬液中的有关物质

试验旨在通过高效液相色谱（high performance liquid chromatography,HPLC）法测定五氯柳胺阿苯达唑复方混悬液的有关物质。采用高效液相色谱法,以自身对照法计算五氯柳胺阿苯达唑复方混悬液有关物质的量。选用Thermo Hypersil BDS C18色谱柱（4.6 mm×150 mm,5 μm）;流动相以0.1%磷酸-10 mmol/L磷酸二氢铵水溶液为A相,以甲醇为B相,31：69（V/V）;流速为1 mL/min;进样量为5 μL;柱温30℃;检测波长295 nm。结果显示,在建立的色谱条件下,五氯柳胺阿苯达唑复方混悬液中的主成分峰与杂质峰均能基线分离。3,5,6-三氯水杨酸、2-氨基-4,6-二氯苯酚盐酸盐、五氯柳胺、阿苯达唑在5~100 μg/mL内与峰面积线性关系良好（R² ≥ 0.999）,定量限分别为5 μg/mL及750、500、225 ng/mL,检测限分别为1 μg/mL及500、250、100 ng/mL,杂质3,5,6-三氯水杨酸、2-氨基-4,6-二氯苯酚盐酸盐总平均回收率分别为101.15%、100.35%,总平均回收率RSD均为0.71%（n=9）。经方法学验证,建立的HPLC方法简单、快速、准确,可用于五氯柳胺阿苯达唑复方混悬液中有关物质的测定。