鸡毒支原体株间结构蛋白及其抗原性变异的比较研究

本研究以ＳＤＳ－ＰＡＧＥ及Ｗｅｓｔｅｒｎ Ｂｌｏｔ技术,应用鸡毒支原体国外强毒株Ｓ６、标准株ＰＧ３１,疫苗株Ｆ,北京分离 ＢＧ４４Ｔ、ＮＢ７２特异性多克隆抗血清对以上五株及疫苗株Ｖ、北京分离株Ｃ的结构及其抗原性进行了比较结果表明ＭＧ结构蛋白及其抗原性存在着株间的多样性和一定相似性,其中以Ｆ与Ｓ６、ＢＧ４４Ｔ与ＰＧ３１、ＮＢ７２与Ｃ更为接近,可能具有同源性。ＳＤＳ－ＰＡＧＥ显示出了ＭＧ株间结构蛋白微     

从疑似IBD病鸡的法氏囊组织中分离到1株ARV

从暴发类似传染性法氏囊病（ＩＢＤ）的江苏省某鸡场采集病鸡法氏囊组织制成组织悬液，接种鸡胚卵黄囊，部分鸡胚３～５ｄ死亡，部分鸡胚不死亡但有病变。用感染胚卵黄囊和绒尿膜混合物，接种鸡胚成纤维细胞（ＣＥＦ），盲传３代后，发现以合胞体为特征的细胞病变（ＣＰＥ）。感染细胞做超薄切片电镜观察，可见细胞浆内病毒粒子呈整齐的晶格状排列。用免疫沉淀法提取病毒抽提核酸，经ＳＤＳ－ＰＡＧＥ电泳，可见规律排列的１０条带，呈３－３－１－３排列。与禽呼肠孤病毒（ＡＲＶ）参考毒株Ｓ１１３３株的核酸谱带的数目和位置相同。血清学试验与ＡＲＶ呈阳性反应，与传染性法氏囊病病毒（ＩＢＤＶ）呈阴性反应。证明分离病毒为ＡＲＶ     

鸡传染性法氏囊病毒强毒株的分离鉴定

从广州市郊区某鸡群送检的６周龄曾经ＩＢＤＶ免疫的病鸡法氏囊中分离到１株ＩＢＤＶ强毒。该毒株能使鸡胚于接种后３６～７２小时内死亡，易感鸡１００％发病，５０％死亡。电镜观察，该病毒颗粒直径６０ｎｍ左右，无囊膜。经ＳＤＳ－ＰＡＧＥ检测，病毒核酸有二条ＲＮＡ带。     

鸽新城疫病毒的分离及其生物学特性测定

用ＳＰＦ鸡胚从疑似鸽新城疫（鸽ＮＤ）病鸽群中分离到一株病毒ＱＬ株,该病毒株能凝集鸡红细胞（ＲＢＣ）,这种凝集作用能被抗新城疫病毒（ＮＤＶ）阳性血清抑制;用抗ＮＤＶ单抗ＰＥＧ夹心ＥＬＩＳＡ测定分离株为阳性。分离株经肌肉注射能使鸽发病和死亡,出现与自然发病鸽一致的症状和病变,但肌注ＳＰＦ鸡只感染,不见临床症状。对该分离株作进一步生物学特性鉴定,按照国际上规定的ＮＤＶ毒力判定标准,测定了该毒株最低致死量致死鸡胚的平均死亡时间（ＭＤＴ）、１日龄雏鸡脑内接种致病指数（ＩＣＰＩ）和６周龄雏鸡静脉接种致病指数（ＩＶＰＩ）,结果ＭＤＴ为１０５小时、ＩＣＰＩ为１．３３、ＩＶＰＩ为１．０。试验结果表明本分离株为鸽新城疫病毒。     

牛轮状病毒重组株的血清学和基因型特性

从母牛接种过Ａ组ＢＲＶ株ＮＣＤＶ－Ｌｉｎｃｏｌｎ（Ｐ１：Ｇ６）苗的两个吡邻牛场分离到两株牛轮状病毒（ＢＲＶ），编号为ＮＳ－１和ＮＳ－２，Ｎｏｒｔｈｅｒｎ－ｂｌｏｔｔｉｎｇ试验表明，ＮＳ－１和ＮＳ－２有相的的Ａ组ＲＮＡ电泳模式，而且全部基因片段同源，体外中和试验表明，ＮＳ－１株病毒能被Ｇ６特异性单克隆抗体（ＭｃＡｓ）和抗ＢＲＶＢ６４１株（Ｐ５：Ｇ６）豚鼠高免血清（ＧＰＡＳ）中和，但不被Ｇ１０特异性Ｍ     

鸡产蛋下降综合症灭活疫苗研究：EDS76—NE4株病毒的培养与鉴定

在对ＥＤＳ７６－ＮＥ４株病毒进行血清学鉴定之后，于鸭胚（ＤＥ）、鸭胚成纤维细胞（ＤＥＦ）、鸡胚成纤维细胞（ＣＥＦ）和鸡胚肝细胞（ＥＣＬ）上适应培养。结果表明，ＥＤＳ７６－ＮＥ４株病毒为鸡产蛋下降综合症病毒，该病毒能在ＤＥ、ＤＥＦ、ＣＥＬ上增殖，在ＤＥ上增殖，尿囊液的血凝价（ＨＡ）可达１：２０４８０－１：３２７６８０倍。     

鸡产蛋下降综合症灭活疫苗研究──EDS_（76）—NE_（4）株病毒的培养与鉴

在对ＥＤＳ７６－ＮＥ４株病毒进行血清学鉴定之后，于鸭胚（ＤＥ）、鸭胚成纤维细胞（ＤＥＦ）、鸡胚（ＣＥ）、鸡胚成纤维细胞（ＣＥＦ）和鸡胚肝细胞（ＣＥＬ）上适应培养。结果表明，ＥＤＳ７６－ＮＥ４株病毒为鸡产蛋下降综合症病毒，该病毒能在ＤＥ、ＤＥＦ、ＣＥＬ上增殖，在ＤＥ上增殖，尿囊液的血凝价（ＨＡ）可达１∶２０４８０─１∶３２７６８０倍。     

鸭霉形体模式株与国内分离株细胞蛋白SDS—PAGE图谱比较

本实验以ＳＤＳ－ＰＡＧＥ技术，对鸭霉形体模式株和国内分离的ＳＱＪ－５Ｃ３株进行了电泳图谱分析。结果表明，模式株与分离株电泳图谱总体上相差不大，但也存在２～３条蛋白带的差异，这说明ＳＤＳ－ＰＡＧＥ技术在霉形体种的鉴定中有一定意义。     

麻雀体内传染性法氏囊病病毒的分离鉴定及理化特性研究

从传染性法氏囊病（ＩＢＤ）阳性麻雀体内分离到了一株病毒，用传染性法氏囊病病毒（ＩＢＤＶ）单克隆抗体心ＥＬＩＳＡ试验和ＤＩＧ－标记ＩＢＤＶｃＤＮＡ探针班点杂交试验证明该病毒为ＩＢＤＶ。病毒可适应于鸡胚和鸡胚成纤维细胞，产生细胞病变效应（ＣＰＥ）。病毒血清型为Ｉ型，病毒代谢抑制试验证明其基因组为ＲＮＡ，病毒核酸的电泳图谱呈两条特征带。病毒对乙醚不敏感ＰＨ２．０不能灭活可使病毒失感染性，５６℃作用３小时     

禽副粘病毒I型结构蛋白分析

鹅副粘病毒ＹＣ９７分离株,鸡源Ｖ９８分离株以及新城疫病毒（ＮＤＶ）Ｆ４８Ｅ８、ＬａＳＯｔａ和Ｃ３０毒株,鸽副粘病毒ＹＺＰＮＦ２分离株经鸡胚增殖纯化后,进行ＳＤＳ－ＰＡＧＥ电泳,结果显示ＹＧ９７和Ｙ９８２个毒株在５６ｋＤ处比另外４个毒株多出一个条带。用单抗２０１０株进行Ｗｅｓｔｅｒｎ ｂｌｏｔ转印,结果该单抗只对ＹＧ９７和Ｙ９８２个毒株的５６ｋＤ条带反应,证明这２株病毒的结构蛋白与经典的新城疫病毒有     

猪白细胞介素18成熟蛋白基因的克隆及在大肠杆菌中的表达

通过RT—PCR方法从用PHA和LPS刺激的猪脾脏细胞中扩增出猪白细胞介素18(pIL-18)成熟蛋白基因的cDNA，克隆到T载体pUCm-T后，序列测定表明，pIL-18成熟蛋白基因核苷酸长度为474bp，编码157个氨基酸。将该基因片段克隆到大肠杆菌表达载体pET-28a构建重组质粒pETIL18m，转化大肠杆菌BL21(DE3)，并用IPTG诱导。重组菌菌体裂解物SDS—PAGE可检测到相对分子质量为19000的重组蛋白，免疫印迹法证实该重组蛋白可以与人IL-18单抗发生特异性免疫反应。     

腺胃病变型鸡传染性支气管炎病毒变异株的比较研究

腺胃病变型鸡传染性支气管炎病毒（ＩＢＶ）变异株Ｈ９５提纯样品经ＳＤＳ－ＰＡＧＥ和Ｗｅｓｔｅｒｎｂｌｏｔｉｎｇ,证明Ｈ９５株单抗ＤＥ７和Ｍ４１株单抗６ＤＨ８均能识别Ｈ９５株５４０００蛋白多肽。采用单抗、多抗介导间接ＥＬＩＳＡ试验表明,Ｈ９５毒株能与抗ＩＢＶＭ４１Ｎ蛋白单抗６ＤＨ８和ＩＢＶＭ蛋白单抗ＭＣ发生反应,也能与抗Ｍ４１、Ｇｒａｙ、Ｈｏｌｔｅ、Ｔ、Ｈ５２、Ｎ１１５和分离株Ｃ９００１、ＤＬＺ９１１１的多抗血清反应,同时抗Ｈ９５株的４株单抗、多抗血清也能与上述毒株反应。卵磷脂酶Ｃ处理的Ｈ９５株的血凝活性能被相应的Ｈ９５株的单克隆抗体和高免血清所抑制,也能被Ｍ４１单抗和高免血清所抑制。通过ＲＴ－ＰＣＲ获得了Ｈ９５毒株的免疫原基因Ｓ１,经Ｓｏｕｔｈｅｒｎｂｌｏｔｉｎｇ和ＩＢＶ的Ｓ探针检测呈阳性。     

Identification of the antigenic components of the virulent Mycoplasma gallisepticum (R) in chickens: their role in differentiation from the vaccine strain (F)

The antibody response to different proteins of Mycoplasma gallisepticum (MG) was studied in chickens experimentally infected with virulent MG R strain. The chickens were challenged at 8 weeks of age by the intranasal route. Each cockerel received 1.3 X 10(6) colony-forming units (CFU). MG strains (R and F) were banded by Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE). The banding pattern was distinctively different between the two strains in the range of 92.5 to 200 kilodaltons (kD). Chicken sera collected at different times following challenge were analyzed by Western blot to determine the patterns of antibodies raised to specific MG proteins (R versus F strains). Early in infection (2 weeks postchallenge), antibodies to 60-kD and 75-kD polypeptides of MG R strain were produced. Subsequently (greater than or equal to 4 weeks postchallenge), antibodies recognized a larger number of MG antigens in both strains. The immunoblot patterns remained the same in the period 8-11 weeks postinfection in each of the two strains; however, the patterns were different when the two strains were compared. The early response recognized the 75-kD protein in the R strain while it recognized the 80-kD protein in the F strain. The late response recognized the 130-kD protein and the protein slightly heavier than 200 kD in the R strain. These two bands did not appear in the immunoblot performed against the F strain of MG. Electroeluted protein of MG R strain, namely adhesin (75 kD), showed a hemagglutination activity (HA) on chicken red blood cells. With the appearance of antibodies specific to the 60-kD and 75-kD polypeptides, there was a significant rise in hemagglutination-inhibition geometric mean titer of chicken sera.     

Differentiation of mycoplasma gallisepticum strains using molecular methods

Increasing use of Mycoplasma gallisepticum (MG) live vaccines has led to a need for the differentiation of MG strains. The MG strains MK-7, MS-16, S6, FS-9 and R strains and the MG live vaccine strain F were compared by random amplification of polymorphic DNA (RAPD) in this study. Using RAPD, different patterns were found among the MG strains. In addition to this, we examined the differentiating potential of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) primers targeted at the crmA, crmB, crmC, gapA, mgc2 and pvpA genes encoding cytadherence-related surface proteins. These proteins may take part in the pathogenesis of MG-induced disease. Differentiation of strain F is based on the identification of restriction enzyme sites in the PCR amplicons. Using HphI enzyme, crmC PCR amplicons produced different RFLP patterns. Digestion of amplicons of gapA-specific PCR with MboI enzyme also produced distinct patterns. Differences were observed among strains R and F by digestion of mgc2 PCR amplicons with HaelIl and VspI enzymes and digestion of pvpA PCR amplicons with AccI, PvulI and ScrFI endonucleases. This method can be used for the rapid differentiation of vaccine strain from wild strains. Differentiation of MG strains is a great advantage for diagnosticians or practitioners and it is useful for epidemiological studies.     

Genetic variation and cross-reactivity of Clostridium septicum alpha-toxin

Clostridium septicum alpha-toxin genes were sequenced with the polymerase chain reaction (PCR) products amplified from DNAs of 25 C. septicum strains, and were classified into 10 patterns. Alpha-toxins were purified from the culture supernatant of four C. septicum strains (strains No. 44, Kagoshima 8, Mie and Tokachi) which were specially chosen from patterns of the deduced amino acid sequences. The molecular weights of the alpha-toxins were not different according to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. However, the isoelectric points between the alpha-toxins of No. 44 and Tokachi strains differed markedly. Cross-neutralization tests were performed with purified alpha-toxins and antitoxins in mice and in Vero cells. Each antitoxin showed roughly the same titers against the four alpha-toxins in mice and completely identical titers against these in Vero cells. Calves immunized with toxoid prepared from the culture supernatant of No.44 strain were challenged by exposure to spores of Mie strain. The toxoid conferred protection against the challenge in calves. From these results, although genetic variation has been observed within the C. septicum alpha-toxin gene, C. septicum strains toxoid of strain No.44 induces protective immunity against exposure to C. septicum that produce other subtypes of alpha-toxin containing several different amino acid residues.     

Humoral immune response of turkeys to strain S6 and a variant Mycoplasma gallisepticum studied by immunoblotting.

Two putative variant Mycoplasma gallisepticum (MG) strains (M876 and M35), originally isolated from commercial turkeys, were compared with eight well-characterized MG strains by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). SDS-PAGE protein profiles indicated that the variant strains were correctly classified as MG based on homologous patterns in species-specific regions of the electrophoretic profiles. However, differences in protein profiles also indicated that variant strains M876 and M35 were different from each other and the other MG strains tested. Immunoblotting was used to assess the humoral immune response of turkeys to infection with the S6 reference strain or M876 variant strain of MG. Immunoblots using antisera to M876 showed that seroconversion to this isolate was slower, and to fewer MG proteins when compared with immunoblots using antisera to S6. Immunoblot analyses further indicated that pooled antisera from turkeys inoculated with either S6 or M876 reacted with each of 10 MG strains tested. However, pooled S6 antisera reacted with greater intensity and with more MG proteins than did pooled M876 antisera. The species-specific immunodominant proteins with the greatest potential for use as antigens in serologic tests appeared to be those of 64 (p64) and 56 (p56) kilodaltons molecular mass.     

Randomly amplified polymorphic DNA (RAPD) analysis of Mycoplasma gallisepticum isolates from turkeys from the central valley of California.

Randomly amplified polymorphic DNA (RAPD) analysis was used to investigate the molecular epidemiology of 26 Mycoplasma gallisepticum (MG) isolates obtained from turkeys located in the central valley of California. The MG isolates were recovered from 5 different companies and 13 ranches. Each company had unique MG strains. No evidence of spread of MG between companies was detected. RAPD analysis of MG isolates within a ranch during an outbreak revealed only a single strain involved in each outbreak. RAPD analysis identified an isolate from 1 ranch with a banding pattern identical to that of the 6/85 vaccine strain, which had been used on that particular ranch. Similar RAPD banding patterns of isolates from different ranches within the same company suggested horizontal spread of MG between ranches. The use of 2 primer sets in RAPD analysis was critical to prevent misinterpretation of relationships between different isolates.     

广东清远鹅弓形虫病血清学调查

本调查采用MAT方法对来自广东省清远市12个规模化养鹅场的520份血清进行了弓形虫病血清学调查。结果发现,所调查的清远市8个肉鹅场中,有2个场弓形虫血清阳性率均为2.22%,其余6个场未发现阳性样品;4个种鹅场均有弓形虫血清阳性样品,阳性率分别为:2.5%、5%、7.5%、2.5%。种鹅的弓形虫感染率(4.38%)明显高于肉鹅(0.56%)。结果表明,清远市规模化养鹅场的鹅弓形虫血清阳性率较低,种鹅弓形虫血清阳性率高于肉鹅,差异显著(P<0.05),种鹅可能成为弓形虫的传播源。     

1株鸡源神经型大肠埃希氏菌的分离及特性分析

从某鸡声以瘫痪、歪颈、昏睡为主要症状的肉雏鸡脑实质中,分离到１株革兰氏阴性、有动力的短杆菌,定名为ＬＣＢ。其主要生化特性为氧化酶阴性、接触酶阳性,发酵葡萄糖、甘露醇,产酸产气,了酵乳糖、山梨醇,不发酵蔗糖、卫茅醇、肌醇,不产生硫化氯,不液化明胶,不分解尿素,Ｍ－Ｒ阳性,Ｖ－Ｐ阴性。经鉴定为大肠埃希氏菌,血清型属Ｏ１３１,为国内外新发现的鸡大肠埃希氏菌的血清型。该菌株腹腔接种对ＫＭ小鼠具有高致病性,