牛生长激素基因（bGH）编码区的遗传变异特征*

 以普通牛、瘤牛、牦牛、大额牛、沼泽型水牛和河流型水牛的代表牛种为对象,探讨不同牛种（或亚种）GH基因编码区序列的遗传变异特征。结果表明,6个群体的GH基因编码区序列全长均为654bp,共检测到16个SNP位点,外显子1无变异位点,外显子2、外显子3、外显子4和外显子5分别有3个、5个、1个和7个变异位点,表明外显子5是编码区的高变区域,而且SNP位点在不同牛种（或亚种）中的分布存在明显差异。16个核苷酸替代位点中有13个为同义突变,仅有3个非同义突变位点,分别位于第2外显子、第4外显子和第5外显子处,并造成其所编码的氨基酸发生改变。     

烘烤定色期不同环境对烤后烟叶香吃味的影响

采用干球温度、干湿球温度差二因素回归最优设计,通过自控烤箱烘烤,研究K326上部叶定色前期烘烤环境对烟叶品质的影响。结果表明:定色阶段随着干球温度和干湿球温度差的增加,烤后烟叶香吃味得分先上升到一个最高值而后呈下降的抛物线变化趋势;干球温度和干湿球温度差过高或过低,皆不利于烟叶香吃味的改善,控制干球温度在44.0～47.0℃,干湿球温度差在4.0～7.0℃时,香吃味的得分相对较高,且易于实际烘烤操作。     

Rodenticide grain bait ingredient acceptance by Norway rats (Rattus norvegicus), California ground squirrels (Spermophilus beecheyi) and pocket gophers (Thomomys bottae)

Vertebrate pest control in California is often accomplished through the use of rodenticide grain baits. These grain baits are composed of steam-rolled oats (SRO), a toxicant, an indicator dye and an oil combination. A series of tests were performed to determine the effects of various dye and oil formulations on acceptance of grain bait by Norway rats [Rattus norvegicus (Berk)], California ground squirrels [Spermophilus beecheyi (Richardson)] and pocket gophers (Thomomys bottae Eyd & Gerv). Seven different dyes, four oil formulations and clean (untreated) oats were tested for acceptance. The addition of the selected oils and dyes to grain resulted in no significant differences in consumption. This indicates that there is a wide variety of dyes that could be used in the formulation of rodenticides. These alternatives could aid in proper pesticide use, the deterrence of bait consumption by birds and possibly in ingredient adhesion to the finished bait.     

Analysis of genetic relations between <Emphasis Type="Italic">Broad bean wilt virus 1</Emphasis> and <Emphasis Type="Italic">Broad bean wilt virus 2</Emphasis>

We determined the complete nucleotide sequence of RNA-1 and the 5-terminal region of RNA-2 from Broad bean wilt virus 1 (BBWV-1) isolate PV132. This report is the first analysis of the genome organization of BBWV-1. We also determined the complete nucleotide sequence of RNA-1 from Broad bean wilt virus 2 (BBWV-2) isolate IP and analyzed the genetic relations between BBWV-1 and BBWV-2. Similar to the BBWV-2 isolates, both RNAs of PV132 encoded a single large polyprotein, which was predicted to contain some functional proteins in a manner similar to those of comovirus. With respect to the deduced amino acid sequences of the mature proteins, PV132 and IP had only 20%–40% homology to comovirus. On the other hand, IP was 73%–98% homologous to BBWV-2 isolates, but PV132 was 39%–67% homologous to the isolates. Although the extent of the homologies differed, the homologies were limited between BBWV-1 and BBWV-2 not only for the coat protein but also for the other proteins. These results clearly support the placement of BBWV-1 and BBWV-2 in the genus Fabavirus as distinct species, proposed on the basis of double immunodiffusion tests.The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession numbers AB084450 (RNA-1 of isolate PV132), AB084451 (RNA-2 of isolate PV132), and AB023484 (RNA-1 of isolate IP)     

Characterization of a New Barley Mild Mosaic Virus Pathotype in France

In March 2002 in a French field, severe mosaic symptoms appeared on plants of the barley cultivar Tokyo with the rym5 locus controlling resistance to all European strains of barley yellow mosaic virus (BaYMV) and barley mild mosaic virus (BaMMV). Electron microscopic examination revealed that the disease symptoms were associated with the presence of flexuous particles which resemble bymoviruses. From these observations and after enzyme-linked immunosorbent assay analysis it was first determined that the plants could be infected by BaMMV and BaYMV. Mechanical transmission of these viruses to the barley cultivar Magie susceptible to both viruses was only possible for BaMMV. This new pathotype (BaMMV-Sil) from Sillery (Marne Department, 51, France), in contrast to another mechanically transmitted French BaMMV isolate (BaMMV-MF), could be transmitted mechanically to two barley cultivars (Tokyo, Misato Golden), Arachis hypogaea, Datura stramonium and Lactuca sativa. BaMMV-Sil was indistinguishable from three BaMMV isolates from Germany (G), Japan (Ka1) and France (PF) by monoclonal antibodies in ELISA while the Japanese isolate (Na1) and BaMMV-MF were distinguishable from all. The sequence of the 3-terminal region of BaMMV-Sil RNA1 was determined. Comparison with previously published sequence data of capsid proteins indicated that BaMMV-Sil was closely related to BaMMV-Ka1, BaMMV-G and another German isolate (BaMMV-ASL1). Resistance-breaking BaMMV strains able to infect cultivars carrying the rym5 locus have also been described in Japan (BaMMV-Na1) and Korea (BaMMV-Kor). No specific amino acid differences were detected between the capsid proteins of BaMMV-Sil, BaMMV-Na1, BaMMV-Kor and those BaMMV isolates that do not overcome the rym5 resistance gene. These results indicate that BaMMV-Sil is a new pathotype of BaMMV in France and suggests that the capsid protein is not the determining factor of the pathogenicity towards the resistance gene rym5.     

Cloning and Sequencing of cnf1 from Escherichia coli Incriminated in Mink and Bovine Colibacillosis

Colibacillosis is responsible for significant losses to the mink and cattle industries. Previous work in our laboratory and by others has suggested that possession of cnf1, the gene encoding cytotoxic necrotizing factor (CNF1), may contribute to the virulence of isolates of E. coli from mink and cattle. The cnf1 gene from E. coli isolated from a mink with colisepticaemia and a bovid with scours was amplified and cloned as a 3.5 kb fragment, and the fragment was sequenced. The cnf1 sequences from the mink and bovine isolates of E. coli were compared to each other and to cnf1 sequences of E. coli from urinary tract and diarrhoea-associated infections of humans. The difference was only 7 nucleotides between the cnf1 sequences of the mink and bovine isolates of E. coli, which translated into 7 differences in amino acids. The cnf1 sequence of the mink isolate of E. coli had 15 nucleotide differences from the cnf1 sequences of the human isolate of E. coli (GenBank X70670), which translated into 11 differences in amino acids between these proteins. The cnf1 sequence of the bovine isolate of E. coli had 14 nucleotide differences from the cnf1 sequence of the human isolate of E. coli (GenBank X70670), which translated into 10 differences in amino acids between these proteins. The highly conserved sequences of the amino acids of CNF1 proteins make them a promising target for detection and control of the CNF1-producing E. coli involved in disease among various host species.     

Detection of Fowl Adenovirus Associated With Hydropericardium Hepatitis Syndrome by a Polymerase Chain Reaction

Hydropericardium hepatitis syndrome HHS), previously unknown in the broiler industry, is an emerging disease that causes severe hydropericardium. A polymerase chain reaction PCR) was developed to detect the fowl adenovirus FAV) associated with HHS. The virus from infectedl ivers was purified, with confirmation by electron microscopy and experimental infection. Methods were developed to isolate the viral DNA from purified virus and infected tissues. Available sequence data on the hexon gene of fowl adenoviruses and other adenoviruses were aligned to determine the conserved and variable regions. Primers were constructed from the alignment data. The amplified fragment consisted of the variable region of the hexon gene flanked by conserved primer sites. Optimum conditions were standardized to achieve the amplification of the desired fragment. As expected, the amplified product was found to be of 0.7 kg size. The nucleotide sequence analysis confirmed the specific nature of the product. Amplification of the specific product could be obtained not only from the DNA isolated from the purified virus but also from the total DNA extracted from infected tissues. The PCR was useful for the detection of FAV associated with HHS.     

新城疫病毒HeB02分离株F基因的序列分析

根据国外已发表的新城疫病毒F基因序列，设计了1对引物，并以RT-PCR特异性扩增出新城疫病毒HeB02分离株的F基因，基因产物大小为1．63kb，与设计相符。对其进行序列测定后，与其他标准毒株F48E9、LaSota和Clone30的F基因进行了同源性比较，结果表明，HeB02株与国内标准强毒株F48E9及目前广泛应用的弱毒疫苗株LaSota和Clone30的F基因核苷酸序列的同源性分别为88.1％、84.9％和83.8％。由此可以看出，HeB02分离株与标准毒株和疫苗株相比，在F基因上发生了变导。     

猪伪狂病病毒粤A株gE基因的克隆与序列分析

参考GenBank中伪狂犬病病毒(PRV)gE基因的序列设计了1对引物,对PRV粤A株gE基因进行了PCR扩增,PCR产物克隆到PMD18-T载体.对重组质粒进行限制性内切酶分析和基因测序,证实了克隆片段的可靠性,并与2株不同来源的毒株进行了同源性分析和比较.     

核酸探针检测犬瘟热病毒方法的建立和初步应用

根据犬瘟热病毒（CDV）基因序列的结构特点,在其编码核衣壳蛋白的高度保守基因区内,设计合成一对特异性引物.以RT-PCR技术从CDV基因中扩增出了一段长度为430 bp的核苷酸cDNA,并制备出地高辛标记的CDV核酸探针.特异性检测结果表明,该探针能与CDV标准株和地方分离株核酸发生特异性杂交,而与对照的NDV、MV等病毒的核酸杂交反应均为阴性.敏感性检测结果表明,该探针对CDV的检出量可达到0.1 pg.用所制备的核酸探针对某宠物诊所疑似犬瘟热病例进行临床诊断初步应用试验,表明该标记探针完全可用于CDV的临床检测.