猪源副黏病毒JL-1株全基因获得及遗传变异分析

利用本实验室分离保存的猪源副黏病毒JL-1株来提取病毒基因组RNA.参考GenBank发表的相关禽副粘病毒Ⅰ型(Avian paramyxovirus serotype 1,APMV-1)基因组序列,设计了8对特异性引物,RT-PCR法分别特异性的扩增出病毒各基因片段,并将各目的基因片段回收纯化,将纯化后的PCR产物进行测序.测定结果得到NP、P、M、F、HN、La、Lb、Lc 8段基因序列,利用DNAMAN软件进行拼接得到基因组全长cDNA序列(GenBank登录号:EU546165).序列分析结果表明,PPMV JL-1株与各地代表株核苷酸同源性87.85%～99.78%,与鹅源新城疫(GPMV)ZJ-1、NA-1株核苷酸同源性分别为83.31%、83.46%,同时根据各毒株F基因开放阅读框前389个核苷酸序列绘制出系统发育进化树,结果表明PPMV JL-1株与LaSota同属于基因Ⅱ型,不同于基因Ⅶ型的ZJ-1和NA-1株的鹅源毒株.     

犬冠状病毒YS1株细胞培养弱毒的实验免疫研究

应用纯化后的犬冠状病毒 (CCV)YS1株细胞培养致弱的弱毒 (CCVYS1V60 ) ,经口鼻和肌肉接种CCV ,SN抗体小于 1∶2的易感犬作安全试验 ,结果未见任何CCV临床症状与病理解剖学改变 ;用不同剂量的该CCV弱毒分组免疫CCV易感犬 ,经SN抗体测定与用CCV强毒攻毒试验 ,结果SN抗体达 1∶60以上的犬 90 %以上可获得免疫保护 ;应用该CCV弱毒分别免疫母源抗体达 1∶4和 1∶8的 2组试验犬 ,第 1次免疫 1 4d后SN抗体均未见升高 ,追加 2～ 3次免疫后 ,SN抗体才逐渐上升至 1∶60以上的免疫保护水平 ;用CCV易感犬和猫肾传代细胞 (CRFK)分别将该CCV细胞培养弱毒连续传 5代和 2 0代 ,结果对犬仍然安全 ,免疫原性也未见下降 ;与犬瘟热病毒 (CDV)、犬传染性肝炎病毒 (ICHV)和犬细小病毒(CPV)弱毒作免疫互扰试验 ,结果与各弱毒的单独免疫结果未见差异 ;该毒的免疫期在 1年以上 ,- 2 0℃冻结保存的保存期为 9个月。     

猫疱疹病毒1型HR-1毒株的分离鉴定及致病性分析

从哈尔滨市某宠物医院疑似感染1型猫疱疹病毒发病猫的眼、鼻拭子中分离到1株病毒,经过电镜观察、分子生物学、血清学和动物回归试验鉴定,分离到的病毒为猫疱疹病毒1型,命名为HR-1株。HR-1可在猫肾细胞(CRFK)上产生典型细胞病变,病毒滴度可达到10~(8 )TCID_(50)/mL。提取病毒基因组DNA经过gD引物扩增后,得到1条1 125 bp大小的特异性条带,经测序表明其与C-27毒株gD基因序列相似性达100%。间接免疫荧光试验(IFA)结果显示,接种HR-1的单层CRFK细胞出现特异性荧光。电镜观察可见圆形、有囊膜、直径约为150 nm的病毒颗粒。为了解该毒株的毒力及致病性,通过感染中国家猫进行致病性试验。结果表明,HR-1为强毒株,对家猫的致死率为100%;HR-1感染家猫后主要表现为眼结膜炎和鼻气管炎;通过实时荧光定量PCR能从感染家猫的眼、鼻拭子中检测到病毒粒子核酸,并且于感染后4～6 d病毒核酸达到最高峰。本试验为猫疱疹病毒的诊断和致病机制的研究提供了参考价值.     

鹅副粘病毒强毒YNG-1株的分离及人工感染试验

采用鸡胚接种法从云南省某鹅场发生烈性传染病的鹅群中分离到一株病毒，经HA，HI试验，鸡胚接种试验，血清中和鸡胚接种试验，确定所分离病毒为副粘病毒，鸡胚半数致死量（ELD50）为10^-8.57/0.1ml。参照国际上规定的新城疫病毒毒力制定标准及其方法，测定该分离株的鸡胚是小致死量致死鸡胚的平均时间（MDT）54h,1日龄雏鸡脑内接种致病指灵敏（ICPI）为1.71,6周龄鸡静脉内接种致病指数（IVPI）为2.36。表明该分离株具有与新城疫病毒速发型相类似的毒力，为强毒株，命名为YNG-1株。人工感染试验结果表明该分离株对6日龄鹅及16日龄鸡致死率均为100%，对6日龄肉鸭无致病性。     

鹅源副黏病毒NA-1株反向遗传操作体系的建立

应用cRACE等方法扩增鹅源副黏病毒NA-1株cDNA5′末端和3′末端,分6段扩增得到病毒的结构基因序列,而后连接本室构建的TLH-T转录载体,构建其cDNA全长克隆。在引入分子标签和验证辅助质粒的功能后,4质粒系统共转染VT7细胞系,成功拯救出了具有感染性的鹅副黏病毒。鹅源副黏病毒NA-1株反向遗传操作体系的建立为进一步深入研究该病毒基因组的功能以及新型疫苗的研发奠定了基础。     

鸽Ⅰ型副黏病毒(S-1株)灭活疫苗免疫剂量研究

为了确定鸽Ⅰ型副黏病毒(pigeon paramyxovirus-Ⅰ,PPMV-Ⅰ)(S-1株)灭活疫苗的免疫剂量。本试验采用3批PPMV-Ⅰ(S-1株)灭活疫苗实验室制品以不同剂量肌肉注射免疫30日龄低抗体幼龄鸽(HI抗体≤2)和120日龄低抗体青年鸽(HI抗体≤2),分别在免疫后第14,28天对试验鸽进行攻毒,对试验鸽进行临床症状、抗体检测和攻毒保护测定。结果显示,该疫苗对低抗体鸽有保护作用,对30日龄幼龄鸽和120日龄青年鸽的最小免疫剂量分别为0.05,0.2mL/只。因此,为了确保疫苗的免疫效果,在PPMV-Ⅰ(S-1株)灭活疫苗制造及检验规程中疫苗用法用量规定:幼龄鸽肌肉注射,0.2mL/只;青年鸽和种鸽肌肉注射,0.5mL/只。     

Genome sequence of an Australian strain of canid alphaherpesvirus 1

Objective

Characterisation of a complete genome sequence of an Australian strain of canid alphaherpesvirus 1 (CHV‐1) and its phylogenetic relationship with other varicellovirus species.

Methods

Standard pathology and PCR methods were used to initially detect herpesvirus in hepatic tissue from an infected 4‐week‐old Labrador Retriever puppy. The complete CHV‐1 genome was sequenced using next‐generation sequencing technology followed by de novo and reference assembly, and genome annotation.

Results

The CHV‐1 genome was 125 kbp in length and contained 74 predicted open reading frames encoding functional proteins, all of which have counterparts in other alphaherpesviruses. Phylogenetic analysis using the DNA polymerase gene revealed that the newly sequenced CHV‐1 clustered with canid alphaherpesvirus isolated from the UK and shared a 99% overall nucleotide sequence similarity.

Conclusion

This is the first complete genome of an Australian strain of CHV‐1, which will contribute to our understanding of the genetics and evolution of herpesvirus.     

鹅源副黏病毒致弱株的“拯救”及分子生物学鉴定

以本课题组前期构建的鹅源副黏病毒NA-1株的全长感染性克隆为模板设计2对引物,用overlap PCR方法将其F蛋白裂解位点处的112、115和117位碱性氨基酸定点突变成为具有典型弱毒株特征的非碱性氨基酸。随后将突变后的F基因序列替换全长感染性克隆的对应序列,构建突变后的克隆质粒FL-cDNA-F′。将改造后的感染性克隆质粒与pCI-NP、pCI-P和pCI-L 3个辅助表达质粒共转染VT7细胞系,成功拯救出了致弱的鹅源副黏病毒。经过分子生物学鉴定,该毒株F基因序列具有典型的弱毒株特征。救获病毒的鸡胚最小致死剂量平均死亡时间(MDT)为96h,表明救获的病毒毒力已被成功致弱,可以作为当前流行的鹅副黏病毒病的一个较为理想的疫苗候选株。     

俄罗斯木霉菌株GAU 1-X-2的生物学特性

从碳氮源、酸碱度及生长温度等方面对俄罗斯木霉(Trichoderma rossicum)菌株GAU 1-X-2的生物学特性进行了研究。结果表明,俄罗斯木霉菌株GAU 1-X-2的生长温度范围为10~35℃,最适温度为20℃;菌落在pH值为5.0~12.0的培养基上能够生长,pH为7.0时,生长最快,pH值为8.0时产孢量最大;营养生长最好的碳源为甘露醇,产孢量最好的碳源为葡萄糖;营养生长最适氮源为蛋白胨,在供试的7种氮源中,培养6d未观测到该菌株产孢;完全黑暗条件有利于菌丝生长和产孢;孢子致死温度为68℃,10min。     

Ⅰ型马立克氏病病毒Md11株pp24基因的真核表达

通过PCR方法扩增MDV Md11株的pp24基因,将其克隆到真核表达载体pcDNA3.1/zeo( )中.阳性克隆鉴定后,在脂质体作用下转染CEF细胞,用间接免疫荧光试验检测,结果证明阳性克隆在CEF细胞中表达了pp24蛋白.     

Evidence for the porcine origin of equine rotavirus strain H-1

Equine group A rotavirus (RVA) strain H-1 (RVA/Horse-tc/GBR/H-1/1975/G5P9[7]) was found to have VP4, VP6-7, NSP1 and NSP4 genes of porcine origin. In order to obtain conclusive information on the exact origin and evolution of this unusual equine strain, the remaining six genes (VP1-3, NSP2-3 and NSP5 genes) of strain H-1 were analyzed in the present study. By whole genomic analysis, strain H-1 exhibited a porcine RVA-like genotype constellation (G5-P[7]-I5-R1-C1-M1-A8-N1-T1-E1-H1), different from those of typical equine RVA strains. The VP2-3 and NSP2-3 genes of strain H-1 were found to originate from porcine RVAs. On the other hand, it was difficult to pinpoint the exact origin of the VP1 and NSP5 genes of strain H-1, though phylogenetically, these genes appeared to be possibly derived from porcine or Wa-like human strains. Taken together, at least nine (VP2-4, VP6-7 and NSP1-4 genes) of the 11 gene segments of strain H-1 were found to be of porcine origin, revealing a porcine RVA-like genetic backbone. Therefore, strain H-1 is likely a porcine RVA strain that was transmitted to horses.     

猪圆环病毒2型GZ-RH1株基因组遗传特征分析

为对猪圆环病毒iDNA新型疫苗、基因组遗传变异以及基因组结构与功能等研究提供科学依据,运用相关生物信息学软件对猪圆环病毒2型(PCV2)贵州仁怀分离株(GZ-RH1)的基因组遗传特征进行了分析。结果表明,PCV2GZ-RH1株基因组结构与pmws(AF027217)株相比存在较大差异,其ORF2基因的第696位因碱基T的缺失而导致移码突变,致使其缺失了ORF8和ORF11,ORF5和ORF10终止密码子提前,其他ORF相对较为保守。PCV2GZRH1株各编码蛋白中除了ORF4和ORF9外,其余都属于亲水性蛋白,且ORF9含有1段信号肽序列。在ORF1和ORF2编码蛋白的磷酸化位点中,ORF1相对较为保守,而ORF2变异较大。ORF1~3所编码的蛋白除均具有各自的蛋白质家族域外,还预测到一些可能具有特殊功能的结构域,如ORF1编码蛋白的NACHT结构域和ORF2编码蛋白的精氨酸富集区。ORF2编码氨基酸位点熵值分析表明,ORF2蛋白氨基酸序列中包含2个高变区,即第53~91位和185~215位。通过构建进化树显示,GZ-RH1分离株系PCV2b亚型。对GZ-RH1株的密码子偏爱性分析表明,相对于大肠杆菌和酵母而言,昆虫细胞更适合于PCV2ORF2基因的体外表达。     

Characterization of an attenuated strain of Actinobacillus pleuropneumoniae, serotype 1

Pleuropneumonia is an important disease of swine caused by Actinobacillus pleuropneumoniae. Putative virulence determinants include capsule, lipopolysaccharide, and cytotoxin. We studied the virulence and virulence determinants of 2 strains: CM5 and CM5A of serotype 1. Strain CM5 was isolated from a pig with pleuropneumonia and passaged once in vitro; strain CM5A was a substrain of CM5 passaged 70 times in vitro. Pigs challenge exposed to an aerosol of 1.3 x 10(7) colony-forming units of CM5/ml died within 30 hours; pigs challenge exposed to an aerosol of 1.6 x 10(8) colony-forming units of CM5A/ml survived. The average thickness of the capsular layer was 137 nm in strain CM5 and 53 nm in strain CM5A in bacteria treated with homologous antibody and examined by transmission electron microscopy. Similarly, capsular material binding polycationic ferritin was found in colonies of strain CM5, but not in strain CM5A. The ratio of hexosamine to protein in extracted capsule of CM5 was more than twice that of CM5A. The polyacrylamide gel electrophoretic profile of the lipopolysaccharide, outer membrane proteins, and whole cell proteins did not differ between the 2 strains. Also, the amount of cytotoxin or endotoxin produced by the 2 strains during the logarithmic growth phase was not different. The electrophoretic profile of restriction endonuclease digested DNA was similar, with the exception of bands in the 750- and 620-basepair regions. It was concluded that attenuation of strain CM5A during in vitro passage was a result of reduced capsule production and that encapsulation is an important virulence determinant of A pleuropneumoniae, serotype 1.     

The characteristics of a variant strain of Brucella melitensis Rev 1

Circumstantial evidence is presented for the occurrence of a variant of a vaccine strain of B. melitensis Rev 1, designated "FSA" (foreign South African). FSA resembles Rev 1 in its reactions to penicillin and streptomycin but reacts closer to a field strain of B. melitensis as regards dye (thionine and basic fuchsin) sensitivity and colony size. Although colonies of Rev 1 were consistently smaller than other B. melitensis strains, their size was 0,75 mm as opposed to the 1-2 mm reported in the literature, while B. melitensis 16M colonies were 1,25-1,5 mm as opposed to the 3-4 mm previously reported. Rev 1 was found to be urease positive, unless a test of low sensitivity was applied.