灯泡贯流式水轮发电机定子三维温度场的研究

建立了发电机定子三维温度场计算的数学模型，以水轮发电机的半齿、半槽为计算区域，用有限元方法对5500kW／6471kVA灯泡贯流式发电机定子的温度场进行了求解，得到了发电机定子的温度场、各部件温度最高点及分布。通过求解定子机座和定子轭部的体平均温度，为机组的设计提供参考。     

双吸三元扭曲叶片离心泵的造型

双吸三元扭曲叶片离心泵具有叶片形状复杂与多流道等特征,其三维造型涉及问题较多,在泵的三维造型中具有普遍性.为此,以GAMBIT软件为设计平台,结合一个具体的双吸离心泵的造型实例,介绍了双吸离心泵扭曲叶片叶轮和螺旋形蜗壳等部件三维造型的方法,并给出了创建实体模型的详细步骤及三维模型图;此外,还简要说明了在Gambit软件中建模需要注意的问题.     

菜粉蝶颗粒体病毒DNA限制性内切酶图谱分析

采用“酶-SDS-酚”法提取的菜粉蝶(Pieris rapae)颗粒体病毒京农801株(PrGV-JN801)DNA,A260/A280=1.85,经琼脂糖凝胶电泳呈现一条带。三种限制性内切酶消化PrGV-JN 801 DNA,其结果分别为:Hind Ⅱ,12个片段;EcoR Ⅰ,15个片段;Bam HI,12个片段。三种酶切所得限制性片段累加分子量的平均值75.04×10~6道尔顿为PrGV-JN 801DNA的分子量。     

Demonstration of Heterogeneous Genotypes of Taylorella equigenitalis Isolated from Horses in Six European Countries by Pulsed-Field Gel Electrophoresis

Forty-six isolates of Taylorella equigenitalis were analysed by pulsed-field gel electrophoresis (PFGE) after separate digestion of the genomic DNA with ApaI and with NotI. The isolates had been obtained from horses in six European countries and were classified into 18 genotypes. In Belgium, 2 genotypes were detected in 2 isolates, in England 9 among 15, in Finland 2 in 2, in France 2 among 10, in Sweden 3 among 5, and in Switzerland 3 among 12. Two English isolates and 4 French isolates gave identical PFGE profiles to those of Kentucky 188 from the United States. A common genotype was found in 5 isolates from Belgium and England and also in 10 isolates from France and Switzerland. The analysis of genomic DNA from 12 isolates of T. equigenitalis obtained from male horses in France, Sweden and Switzerland gave no evidence of a sex-related difference in the genomic DNA. Genomic DNA from 11 streptomycin (STM)-susceptible isolates obtained in Sweden and Switzerland were classified into four genotypes by PFGE. Each of the six genotypes determined among the 17 isolates from these two countries had single phenotypes for resistance or susceptibility to STM.     

Application of a putative fatty-acid binding protein to discriminate serologically the two European quarantine root-knot nematodes, Meloidogyne chitwoodi and M. fallax, from other Meloidogyne species

Two major proteins, Mcf-A67 and Mcf-B66, were identified by mini two-dimensional polyacrylamide gel electrophoresis in order to distinguish the two European quarantine root-knot nematodes, Meloidogyne chitwoodi and M. fallax, from eight other species. These quarantine proteinic markers have been microsequenced after enzymatic digestion. The internal amino acid sequences exhibit similarities to members of a family of low molecular weight intracellular lipid-binding proteins. Moreover, to explore a simple, rapid, and inexpensive way to identify the two quarantine nematodes, dot blot hybridizations were performed using an antiserum (A67) produced from the longest amino-acid sequence of the protein Mcf-A67. Although several proteins stained on the M. chitwoodi and M. fallax western blot membranes, the two nematodes were easily distinguished from other root-knot nematodes, on dot blot assays with soluble proteins extracted from a single female. Because of its specificity and sensitivity, the use of the A67 antiserum to improve the diagnosis of the two European quarantine root-knot nematodes is discussed.     

马铃薯纺锤块茎类病毒的检测和防治

马铃薯纺锤块茎类病毒病(potato spindle tuber viroid,PSTVd)是一种严重为害马铃薯生产的病害,降低产量20%—30%。防治的主要措施是应用无类病毒的种薯。由于目前还没有脱掉类病毒的有效措施,只能从未被饱和侵染的群体中鉴定筛选出未被侵染的个体,再脱掉其它病毒,作为核心繁殖材料。1987年以来,利用自制的电泳设备,以往复聚丙烯酰胺凝胶电泳法(return-polyacrylamide gel electrophoresis,R-PAGE)检测类病毒,筛选出未感病的个体,再用茎尖组织培养法脱掉其它病毒。经用马铃薯卷叶病毒等8种病毒酶标抗体鉴定筛选,获得既无类病毒也无主要马铃薯病毒的克新1、2、3和4号等主栽马铃薯品种的核心种。并已提供给省内外的良种场繁殖推广。1989和1990年抽样检测克山良种场繁殖的原种、一级和二级良种,未检测到类病毒。     

Specificity of polycllonal and monoclonal antibodies for the identification of Xanthomonas campestris pv. campestris

Polyclonal and monoclonal antibodies (PCAs and MCAs), produced to whole cells and flagellar extracts ofXanthomonas campestris pv.campestris (Xcc), respectively, were tested for specificity. In immunofluorescence microscopy (IF) the three PCAs tested, reacted at low dilutions with all Xcc strains, some other xanthomonads and non-xanthomonads. At higher dilutions most cross-reactivity with non-xanthomonad strains disappeared. However, the cross-reactivity with strains ofX. c. pv.vesicatoria (Xcv),X. c. pv.amoraciae (Xca) andX. c. pv.phaseoli var. fuscans (Xcpf) remained.Six MCA-producing cell clones viz. 20H6, 2F4, 18G12, 10C5, 17C12 and 16B5 were selected for specificity tests with an enzyme immunoassay (EIA), IF and a dot-blot immunoassay (DBI). None of the MCAs reacted with all Xcc strains in IF and EIA. In DBI, only MCAs 17C12 and 16B5 reacted with all Xcc strains. All six MCAs tested, cross-reacted in one of either tests with other pathovars ofX. campestris, such as Xcv or Xca. The MCAs were also tested in immunoblotting experiments using total bacterial extracts, cell envelope and flagellar extracts. MCAs 20H6, 2F4, 18G12 and 10C5 reacted with the lipopolysaccharide (LPS) of Xcc. MCAs 16B5 and 17C12 reacted with a 39 kilodalton and a 29 kilodalton protein, respectively.It is concluded that the PCAs and MCAs discussed in this study may be used for routine identification and differentiation of (a group of) Xcc strains. The significance of the cross-reactions with other pathovars ofX. campestris needs to be determined by testing seed lots.     

条锈菌侵染早期小麦叶片RNA和rRNA的合成

 采用示踪方法研究了条锈菌侵染早期小麦叶片的RNA和rRNA合成。结果表21h期间,表现不亲和性反应的叶片总RNA合成有所增加,而亲和性反应寄主叶片则低rRNA合成未受侵染影响。在接种后39~45h期间,只有呈亲和性反应的寄主叶片RNA和大幅度增加。对rRNA各组分合成的测定表明条锈菌侵染所影响的只是大分子量rRNA,胞质和叶绿体rRNA的合成也存在差别。文中讨论了上述变化的病理学意义。     

The induction of 1,3-β-glucanases and other enzymes in groundnut leaves infected with Cercospora arachidicola

Infection of groundnut leaves with the early leaf spot pathogen Cercospora arachidicola leads to a marked increase in extracellular 1,3-β-glucanase activity, limited to the infected tissue. Three isoforms of low molecular weight and extreme pI values, typical of pathogenesis-related proteins, were induced. These β-glucanases, when acting together, were capable of degrading the pathogen cell wall in vitro. Glucanases from homogenates of infected leaf tissue were partially purified by ion-exchange chromatography to give enzymes with molecular weights of 35, 32 and 20 kDa and pI values of 3·8, 3·6 and > 9, respectively. They were electrophoretically identical to the β-glucanases found in the intercellular washing fluid. Treatment of groundnut plants with 200 μM mercuric chloride induced the accumulation of identical extracellular β-glucanases. During the course of the infection an increase in peroxidase activity was also observed, but chitinase activity remained more or less constant.