四种禽源支原体核酸限制性酶切图谱分析

以ＥｃｏＲＩ、ＨｉｎｄＩＩＩ酶解四种食源支原体基因组ＤＮＡ所获得的片段用琼脂糖凝胶进行电泳。结果表明，四种禽源支原体基因组ＤＮＡ经上述酶切后所获得的片段图谱有很大的差异性，表明它们之间的相关性很小；８个鸡毒支原体菌株ＤＮＡ经酶切，电泳后所获得的片段亦具有相对的差异性，说明酶切图谱分析不适用于禽类支原体各的鉴定。由于该技术有很高的分辨率，可以区分同种不同株之间的基因差异，因此，这种技术对禽类支原体病     

鸡痘病毒基因组酶切片段的克隆及酶谱分析

以鸡胚成纤维细胞培养的中国鸡痘病毒鹌鹑化弱毒株，经蔗糖密度梯度离心法纯化，电镜观察示所得病毒为典型鸡瘟病毒颗粒。以蛋白酶Ｋ法抽提病毒基因组，电泳结果为典型的大分子量ＤＮＡ特征，经ＥｃｏＲＩ或ＥｃｏＲＩ／ＨｉｎｄⅢ酶切，插入ｐＵＣ１９载体相应位点，经转化、筛选、鉴定后得相应酶切片段的基因组文库。对其中２３个克隆片段用双酶法进行酶谱分析，绘制出了相应克隆片段的酶切图谱，每个克隆片段中均有１～６个可以利用的插入位点。基因组文库的构建及部分克隆片段的酶谱分析为进一步筛选病毒复制非必需片段以构建重组疫苗表达载体乃至鸡痘病毒分子生物学的研究打下了坚实的物质基础。     

限制性内切酶片段长度多态性在几个绵羊品种中的研究

本文利用羊的促卵泡激素（ＦＳＨ）ｃＤＮＡ，胸腺（Ｔｈｙｍｕｓ）基因组ＤＮＡ及卵泡抑止素（Ｆｏｌｌｉｓｔａｔｉｎ）ｃＤＮＡ等３种探针与泰国长尾羊，喀麦隆羊（Ｃａｍｅｒｏｏｎ）及它们Ｆ１代杂种的基因组ＤＮＡ进行分子杂交，结果在ＥｃｏＲＩ，ＨｉｎｄⅢ和ＴａｑⅠ酶切的ＤＮＡ片段与ＦＳＨｃＤＮＡ杂交的图谱上，可观察到ＲＦＬＰ的存在，并可根据某些特殊区带的存在与否区别两个不同种的羊。用ＥｃｏＲＩ酶切的ＤＮＡ片段与胸腺基因组ＤＮＡ探针杂交，也发现了ＲＦＬＰ，而其它３种酶的酶切片段与此探针杂交，个体间的图谱是一致的。利用本实验所采用的４种限制性内切酶，在所测定品种及杂交种的卵泡抑止素位点没有发现变异。     

鸡痘病毒基因组酶切片段的克隆及酶谱分析

以鸡胚成纤维细胞培养的中国鸡痘病毒鹌鹑化弱毒株，经蔗糖密度梯度离心法纯化，电镜观察示所得病毒为典型鸡痘毒颗粒，以蛋白酶Ｋ法抽提病毒基因组，电泳结果为典型的大分子量ＤＮＡ特征，经ＥｃｏＲＩ或ＥｃｏＲＩ／ＨｉｎｄⅡ酶切，插入ＰＵＣ１９载体相应位点，经转化、筛选、鉴定后得相应酶切片段的基因组文库，对其中２３个克隆片段用双酶法进行酶谱分析，绘制出相应克隆片段的酶切图谱，每个克隆片段中均有１－５个可以利用的     

限制性内切酶片段长度多态性有几个绵羊品种中的研究

本文利用羊的促卵泡激素（ＦＳＨ）ｃＤＮＡ，胸腺基因组ＤＮＡ及卵泡抑止素ｃＤＮＡ等３种探针与泰国长尾羊，咯麦隆羊及它们Ｆ１代杂种的基因组ＤＮＡ进行分子杂交，结果在ＥｃｏＲＩ，ＨｉｎｄⅢ和ＴａｑⅠ酶切的ＤＮＡ片段与ＦＳＨ ｃＤＮＡ杂交的图谱上，可观察到ＲＦＬＰ的存在，并可根据某些特殊区带的存在与否区别两个不同种的羊。用ＥｃｏＲⅠ酶切的ＤＮＡ片段与胸腺基因组ＤＮＡ探针杂交，也发现了ＲＦＬＰ，而其它３种酶     

一个水貂近交群体的DNA指纹分析

从一个长期闭锁繁育的水貂群体采集鲜肝样本，分离基因组ＤＮＡ，用人源小卫星探针３３．１５和内切酶ＨａｅⅢ制备ＤＮＡ指纹图谱。     

产蛋下降综合征（EDS－76）病毒DNA酶切图谱分析

选用ＥｃｏＲＩ、ＰｓｔⅠ、ＰｖｕⅡ、ＨｉｎｄⅢ、ＢｇｌⅠ和ＢｇｌⅡ６种限制性内切酶，对国内４株ＥＤＳ－７６病毒鸡源分离株和国外标准株ＡＶ－１２７及１株鹅源腺病毒的ＤＮＡ进行酶切图谱的比较，结果发现４种鸡源分离株与ＡＶ－１２７株用上述６种酶切的片段数分别为４、８、１０、１０、６和７条。各酶切图形、片段大小亦十分相似，表明均为ＥＤＳ－７６病毒。ＥｃｏＲＩ－ＨｉｎｄⅢ和ＰｓｔＩ－ＥｃｏＲＩ的双酶切也得到同样结果。鹅源分离株的酶切片段数分别为６、７、９、７、４和１０条，酶切图形和片段大小均与ＡＶ－１２７有很大不同，表明该分离株可能为１株血清型相同而基因组不同的ＥＤＳ－７６鹅腺病毒。     

几种鸟类mtDNA限制性酶切图谱的比较研究

本文用５种限制内切酶（ＨｉｎｄⅢ，ＢｇＬＩ，ＰｓｔＩ和ＢａｍＨＩ）初步建立了头鹅、白鹅、火鸡和鹌鹑的肝脏线粒体ＤＮＡ的内切酶图谱。结果表明白鹅和狮头鹅的ｍｔＤＮＡ的酶切图谱极为相似。山鸡、火鸡和鹌鹑的ｍｔＤＮＡ限制性性内切酶图谱之间的差异是很大的，以上事实说明驯化中的鹅类的不同品种间ｍｔＤＮＡ差异不在。而鸡形目中的不同物种间的ｍｔＤＮＡ是有很大的差异的。     

适于家蚕AFLP标记的酶切反应系统

ＡＦＬＰ作为一种新的分子标记技术，其成功的关键依赖于ＤＮＡ的酶解效果，本文使用ＰｓｔＩ、ＴａｑＩ两种限制性内切酶，选用不同的酶切方式与不同的反应离子的组合对家蚕ＢＣ１代基因组ＤＮＡ进行酶切、通过人工接头连接、二次扩增及ＰＡＧＥ电泳、银染检测，结果显示是两酶在２５ｍＭＴｒｉｓ－Ａｃｅｔａｔｅ（ＰＨ７．８）、１００ｍＭＫＡｃ、１０ｍＭＭＧＡｃ２、１ｍＭＤＴＴ反应系统中能得到多态性丰富、重复性好的ＤＮＡ指纹图谱。同时，表明寻求适宜的限制酶缓冲组分是十分重要的。     

含PRRS病毒ORF5的伪狂犬病病毒TK基因缺失转移载体的构建

提取伪狂犬病病毒（ＰＲＶ）ＢａｒｔｈａＫ６１株基因组ＤＮＡ,用限制性内切酶ＫｐｎＩ充分消化,回收５．９ｋｂ片段（Ｊ片段）,将其克隆于质粒ｐＵＣ１１９ ＫｐｎＩ位点上,获得ｐＢＫＪ。用两对针对ＰＲＶ ＴＫ基因的特异性引物对重组质粒进行ＰＣＲ鉴定,证明其中含有ＰＲＶ ＴＫ基因。然后用ＫｐｎＩ、ＰｓｔＩ和ＢａｍＨＩ等限制性内切酶对其进行酶切分析,确定了克隆片段的物理图谱。进一步研究证实ＴＫ基因位于其中的     

Demonstration of the genetic stability of a Mycoplasma gallisepticum strain following in vivo passage.

A Mycoplasma gallisepticum strain designated 6/85 (MGI) exhibiting reduced virulence for both chickens and turkeys was sequentially passaged 10 times in each species. DNA extracted from organisms before passage and those isolated after the third, sixth, and 10th passages was studied by restriction endonuclease DNA analysis using BamHI, BglII, EcoRI, HindIII, and PstI endonucleases. The virulent-type strain designated S6 was used as a comparison. Comparison of DNA fragment patterns of MGI and S6 strains showed distinct differences, although some similarities were evident. Passage of the strain in vivo did not affect DNA fragment patterns of the MGI strain. Electrophoretic protein patterns produced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed very similar band patterns in both the MGI and S6 strains. The most notable differences were seen in bands located in the molecular-mass regions of approximately 46.5, 50-54, 58-64, and 105-140 kilodaltons. Alteration of band pattern profiles following in vivo passage of the MGI strain was apparent in a single band at approximately 86 kilodaltons that appeared to stain more intensely following passage.     

Ribosomal RNA gene probes to detect intraspecies heterogeneity in Mycoplasma gallisepticum and M. synoviae

Intraspecies genotypic heterogeneity among strains of Mycoplasma gallisepticum and M. synoviae was tested using genomic fingerprints with a ribosomal RNA (rRNA) gene probe. The organism's DNA was digested by a restriction endonuclease, electrophoresed, transferred to a nitrocellulose sheet, and hybridized with 32P-labeled pMC5 plasmid carrying the highly conserved rRNA genes of M. capricolum. The resulting hybridization patterns indicated a degree of genotypic heterogeneity among M. gallisepticum strains more pronounced than among the M. synoviae strains tested. Most importantly, the live vaccine F strain of M. gallisepticum could be distinguished from virulent field isolates of this species, enabling the detection and identification of the F strain in areas in which vaccination with this strain has taken place. Genomic fingerprints with an rRNA gene probe can thus be added to the battery of tools useful in taxonomy at the intraspecies level and in epidemiology of mycoplasmosis in poultry.     

Genotyping of Mycoplasma gallisepticum and M. synoviae by Amplified Fragment Length Polymorphism (AFLP) analysis and digitalized Random Amplified Polymorphic DNA (RAPD) analysis

Mycoplasma gallisepticum (MG) and M. synoviae (MS) are the cause of considerable economic losses in the poultry industry. Molecular differentiation of avian Mycoplasma strains may be helpful in tracing infections and in the evaluation of implemented intervention strategies. Amplified Fragment Length Polymorphism (AFLP) has shown to be a powerful typing technique but the application for poultry Mycoplasma strains is very limited. The aim of this study was to evaluate the reproducibility and discriminatory power of AFLP HindIII/HhaI and AFLP BglII/Mfel for the inter- and intraspecies differentiation of avian mycoplasmas and to compare these test characteristics with digitalized Random Amplified Polymorphic DNA (RAPD) analysis. The reproducibility of RAPD, AFLP HindIII/HhaI and AFLP BglII/Mfel was 50-100, 97-98 and 86-99%, respectively. RAPD and both AFLP enzyme combinations were able to differentiate between five avian Mycoplasma species. For AFLP, five MG and four MS clusters could be identified. The phylogenetic tree for both enzyme combinations was comparable. For RAPD, four MG clusters could be identified. For MS, however, due to the poor reproducibility of the RAPD technique, no clear genogroups could be identified. On basis of the results of this study it can be concluded that AFLP is a powerful technique for the genotyping of avian mycoplasmas and that, although AFLP HindIII/HhaI generated patterns with less fragments, the final results showed homologous results.     

A study of the predominant genotypes of bovid herpesvirus 1 found in the U.K

The genotypic classification of 84 U.K. isolates of bovid herpesvirus 1 was determined by the restriction endonuclease technique. Preliminary studies with six enzymes (EcoRI, HindIII, HpaI, BamHI, PstI and BstEII) showed that the principal genotypic variants, including the live vaccine strains used in the U.K., could be identified from the digestion patterns with just two endonucleases: HindIII and HpaI. Isolates from the 1960s were all categorised as genotype 2b. From 1977 onwards, genotype 1 has predominated in mainland Britain, with occasional type 2b isolates. Type 2b viruses were isolated from both respiratory and genital disease cases. There was no evidence of genotypes 2a or 3 in the U.K.     

DNA homology of Brucella abortus strains 19 and 2308

The restriction endonuclease digestion DNA patterns from Brucella abortus strains 19 and 2308 were examined with 11 restriction enzymes (AvaI, BamHI, BglII, BstEII, DdeI, EcoRI, HindIII, KpnI, PstI, XbaI, and SalI). The DNA electrophoretic banding patterns between the 2 strains were highly similar, using this restriction enzyme analysis. Differences were not discernable between B abortus strains 19 and 2308 in any of the restriction banding patterns examined. Methylation at CCGG or GATC sites was not detectable on the basis of digestion with isoschizomers (HpaII and MspI, and DpnI, Sau3AI and MboI). Homology between B abortus strains 19 and 2308 was assessed, using solution-hybridization techniques followed by S1 nuclease assays. Results of these reassociation experiments indicated 98.6 to 99.3% homology between B abortus strains 19 and 2308 with 13.5 to 18.6% homology between B abortus (strains 19 and 2308) and the E coli HB101 control. We concluded that any DNA differences between the 2 B abortus strains are small and will require analysis at the DNA sequence level.     

Differentiation of the vaccine F-strain from other strains of Mycoplasma gallisepticum by restriction endonuclease analysis

The electrophoretic patterns of the nucleic acids (DNA) of Mycoplasma gallisepticum strains digested with the restriction enzymes Bam HI, Eco RI and Hind III were useful for differentiating the vaccine F-strain from other strains of M. gallisepticum. The procedure was more sensitive than the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) technique. The vaccine F-strain, represented by cultures designated F-K810 and F-F2F10 was clearly differentiated from other strains of M. gallisepticum. This procedure may be useful in field studies to determine if the vaccine strain will replace wild-type M. gallisepticum in commercial layers.     

Restriction endonuclease analysis of infectious laryngotracheitis viruses: comparison of modified-live vaccine viruses and North Carolina field isolates

Six modified-live (ML) infectious laryngotracheitis (ILT) vaccine viruses, three reference strains, and 18 field isolates were compared by restriction endonuclease analysis of their DNA. Viral DNA digestion patterns were established for vaccine viruses using restriction endonucleases PstI, BamHI, KpnI, and HindIII. Using these enzymes, five of six ML vaccine viruses had identical restriction endonuclease cleavage patterns. Vaccine viruses had distinct patterns compared with ILT virus reference strains Illinois-N71851, Cover, and NVSL. Restriction endonuclease cleavage patterns of 18 field isolates of ILT virus, obtained from ILT outbreaks in North Carolina, were indistinguishable from vaccine viruses. These results suggest a possible role of vaccine or vaccine-like viruses in recent ILT outbreaks.     

Genetic and antigenic relatedness between Mycoplasma gallisepticum and Mycoplasma synoviae

The two avian pathogens Mycoplasma gallisepticum and Mycoplasma synoviae were found, by Southern blot hybridization of their digested DNAs, to share genomic nucleotide sequences additional to those of the highly conserved ribosomal RNA genes. The assumption that some of the shared sequences encode for antigens or epitopes common to both mycoplasmas was supported by Western immunoblot analysis of cell proteins of one mycoplasma with specific antiserum to the other mycoplasma. Interestingly, the band patterns of reactive antigens were different for some of the M. gallisepticum strains, supporting the concept that the species is genotypically variable. The results of the present study may explain the cross-reactivity of the two mycoplasmas noted previously in a variety of routine serological tests.     

A survey of avian Mycoplasma species for neuraminidase enzymatic activity

Among 23 currently recognized avian Mycoplasma (AM) species only Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma meleagridis and Mycoplasma iowae cause disease and loss of production in chickens and/or turkeys. Because neuraminidases are considered virulence factors in many pathogenic microorganisms the aim of our study was to determine which AM species possess neuraminidase enzymatic activity (NEAC). Small samples of AM cells were assayed for NEAC using the chromogenic substrate 5-bromo-4-chloro-3-indolyl-alpha-d-N-acetylneuraminic acid. In the case of positive NEAC reaction the substrate gave the insoluble indigoblue product what enabled simple test and easy estimation of NEAC. M. gallisepticum and M. synoviae which share sequences of the gene encoding neuraminidase (sialidase NanH) exhibited considerable levels of NEAC. However, NEAC levels differed among their strains, as well as among cultures of different strains. Only certain cultures of the type strain of M. meleagridis showed NEAC, whereas among six serovars of M. iowae only serovar I (type strain 695) showed NEAC. Weak NEAC was detectable in M. anseris, M. cloacale and M. pullorum, whereas the type strain of M. corogypsi (BV1) showed strong NEAC. Our study provides novel informations about NEAC in AM species and suggests that higher invasiveness and possibly, the pathological processes might be associated with their NEAC.     

Comparative study of Mycoplasma pulmonis and Mycoplasma gallisepticum infections in turkey sinus.

Infraorbital sinuses of young turkeys were injected with virulent strains of Mycoplasma pulmonis and Mycoplasma gallisepticum to compare the diseases caused by the 2 agents. Mycoplasma pulmonis did not cause visible swelling from large quantities of mucous exudate in the sinuses, such as occurs with M gallisepticum, and it could not be recovered by bacteriologic culture technique after 3 weeks. However, slight exudate did accompany the M pulmonis infection. Similarities between the disease caused by M pulmonis and that caused by M gallisepticum included lymphocytic infiltration in the submucosa, swollen epithelial cells, and loss of cilia from sinus epithelial cell surfaces. This strain of M pulmonis, which is pathogenic for rats, was only mildly pathogenic for turkeys and the infection did not persist for long.