桃红叶植原体检测及鉴定   总被引：2，自引：0，他引：2  

张华明  蔡红  陈海如  葛晓琴 《植物检疫》2005,19(1):7-11

对表现红叶的桃植株进行植原体16SrRNA基因PCR扩增,得到1.2kb的特异片段.将此片段与pGEM T Easy载体连接并转化到大肠杆茵DH5α感受态细胞中.通过酶切、PCR鉴定,对筛选得到的重组阳性克隆进行序列测定及同源性比较分析,确定该株系属于翠菊黄化植原体组(Aster yellows group,16SrI).在国内首次报道了翠菊黄化组中的植原体侵染桃树.  相似文献   

中国禽(番鸭)呼肠孤病毒分离株S1基因全序列分析   总被引：14，自引：0，他引：14  

王劭  邓国华  吴异健  吴宝成  陈化兰 《中国预防兽医学报》2005,27(2):105-111

采用RT-PCR技术,分别以DRV-YH、DRV-YJL两株中国禽(番鸭)呼肠孤病毒RNA为模板,扩增了S1全基因的cDNA片段.将S1 cDNA克隆到T载体后进行序列测定,测序结果表明所扩增的cDNA片段长1643个核苷酸,包含了完整的S1基因的三个开放阅读框架(ORF1,ORF2和ORF3)和基因两端的非编码区.核苷酸序列比较分析结果表明:DRV-YH与ARV-S1133,176分别有6个,10个核苷酸的差异,DRV-YJL与ARV-S1133,176分别有8个,12个核苷酸的差异,DRV-YH与DRV-YJL有4个核苷酸的差异.  相似文献   

中国禽(番鸭)呼肠孤病毒YB株S4基因序列分析   总被引：5，自引：0，他引：5  

王劭  邓国华  吴异健  吴宝成  陈化兰 《中国预防兽医学报》2005,27(6):445-449

应用非免疫番鸭胚增殖中国禽(番鸭)呼肠孤病毒YB分离株,用LSTRIAZOL提取病毒RNA,反转录-聚合酶链反应(RT-PCR)扩增中国禽(番鸭)呼肠孤病毒YB分离株S4基因节段cDNA.将S4cDNA克隆到PMDl8-T载体上,并进行了鉴定和核苷酸序列测定.序列分析结果,克隆的S4cDNA共1 124bp,包括非编码区和完整的阅读框架.分子进化系统分析表明该毒株与禽呼肠孤病毒(鸡呼肠孤病毒)的亲缘关系较远,DRV-YB与DRV-89330同缘率为93.3%.  相似文献   

Association of aster yellows subgroup 16SrI-B phytoplasmas with a disease of Rehmannia glutinosa var. purpurea   总被引：1，自引：0，他引：1  

J. P&#;ibylovᆠ J. &#;pak  J. Fránová  K. Petrzik 《Plant pathology》2001,50(6):776-781

A new phytoplasma disease of Rehmannia glutinosa var. purpurea was observed in the Czech Republic in 1998. Infected plants showing severely proliferating shoots, leaves reduced in size with vein clearing and chlorosis, shortened internodes and virescent petals died in advanced stages of the disease. Electron microscopy examination of the ultra-thin sections revealed the presence of numerous polymorphic bodies in phloem tissue of leaf midribs and petioles. The disease was successfully transmitted from infected plant via a dodder bridge into periwinkle ( Catharanthus roseus ). The phytoplasma aetiology of this disease was further confirmed by polymerase chain reaction (PCR) using universal primers R16F2/R16R2. Restriction fragment length polymorphism (RFLP) analysis of amplification products indicated the presence of aster yellows related phytoplasmas (16SrI-B) in naturally infected samples of R. glutinosa var . purpurea and in symptomatic periwinkle after dodder transmission of the agent. A comparison of the amplified sequence with 17 sequences available in the GenBank confirmed the classification of the phytoplasma in the subgroup 16SrI-B. This is the first report of natural occurrence of phytoplasma-associated disease in R. glutinosa var. purpurea.  相似文献   

葡萄保鲜中的硫伤害研究   总被引：7，自引：0，他引：7  

郭哲  努尔尼莎 《干旱区研究》1992,9(3):64-66

离体葡萄果实接触二氧化硫气体,在发生伤害的情况下,可引起细胞汁液pH的降低和组织质膜差别透性的增加,这种变化在一定范围内与硫伤害程度相关。电导率在伤害出现前有一峰值,而pH值呈较缓的降低趋势。以电导率变化做为细胞功能恢复的参照指标,结果表明“无核白”葡萄比“沙力皮”葡萄有较强的伤害恢复能力。  相似文献   

Emended descriptions of indole negative and indole positive isolates of Brachyspira (Serpulina) hyodysenteriae     

Fellström C  Karlsson M  Pettersson B  Zimmerman U  Gunnarsson A  Aspan A 《Veterinary microbiology》1999,70(3-4):225-238

Two type/reference strains of Brachyspira (B.) hyodysenteriae, 14 Belgian and German indole negative, and 14 Belgian, German and Swedish indole positive field isolates of strongly β-haemolytic intestinal spirochaetes were compared by pulsed-field gel electrophoresis (PFGE) patterns, biochemical reaction patterns, 16S rDNA sequences and MIC determinations of six antibacterial substances. Three tests for indole production, including a spot indole test, were compared with congruent results. All field isolates were classified as B. hyodysenteriae due to a high genetic and phenotypic similarity with the type strains. The Belgian and German indole negative isolates had identical and unique PFGE patterns for the tested restriction enzymes MluI and SalI, as well as identical 16S rDNA sequences, and they could not be differentiated by any of the methods used. Seven unique PFGE patterns were achieved from the 14 indole positive field isolates. The patterns were identical and unique for epidemiologically related isolates. Type/reference strains and isolates without known relation to other tested isolates showed unique banding patterns. The MICs of tylosin, tiamulin, erythromycin, clindamycin, carbadox and virginiamycin were determined in broth for all isolates. In contrast to Belgian and German isolates, the majority of the Swedish field isolates were susceptible to tylosin, erythromycin and clindamycin. Probable pathways of infection for some of the Swedish isolates were determined. The PFGE patterns of epidemic clones of B. hyodysenteriae remained stable for a period of up to 8 years. In vivo development of resistance to macrolide and lincosamide antibiotics due to use of tylosin was clearly indicated for two epidemic clones.  相似文献   

Effects of N-methyl-D, L-aspartate on secretion of growth hormone-releasing hormone from the boar hypothalamic-preoptic area and median eminence in vitro     

Estienne MJ  McElwain KV  Barrett JB  Barb CR 《Domestic animal endocrinology》1999,17(4):1156-407

N-methyl-D, L-aspartate (NMA) elicited secretion of growth hormone (GH)-releasing hormone from both the hypothalamic-preoptic area and the median eminence that were collected from boars. We suggest that the previously described increase in GH secretion that follows peripheral treatment of swine with NMA is attributable, at least in part, to NMA-stimulated secretion of GH-releasing hormone from the central nervous system.  相似文献   

Molecular and biological characterisation of Cryptosporidium in pigs   总被引：1，自引：0，他引：1  

Morgan UM  Buddle JR  Armson A  Elliot A  Thompson RC 《Australian veterinary journal》1999,77(1):44-47

OBJECTIVE: Genetic and biological characterisation of 12 isolates of Cryptosporidium from pigs and comparing them with Cryptosporidium isolates from humans and cattle. DESIGN: Cryptosporidium isolates from pigs were compared with those obtained from human and cattle using rDNA sequence analysis. The infectivity of two of the porcine isolates was determined in neonatal mice and the clinical history of the infected pigs recorded. RESULTS: Pig-derived isolates of Cryptosporidium exhibited two distinct genotypes; a porcine genotype and a bovine genotype, which is common to cattle and other livestock. The porcine genotype did not produce any infection in neonatal mice whereas the bovine genotype did. CONCLUSION: Two distinct genetically and biologically differing strains of Cryptosporidium appeared to be associated with acute diarrhoea in pigs. Whether Cryptosporidium was a primary or secondary pathogen is unclear but warrants further investigation. As the bovine genotype is known to infect humans, the results suggest that pigs can act as reservoirs of cryptosporidial infections for humans and other live-stock. The zoonotic potential of the pig-adapted genotype is uncertain and requires further study.  相似文献   

以党的十六大精神为指导,努力创建一流大学     

赵冬初 《湖南农业大学学报(自然科学版)》2003,(2)

认真学习十六大报告,切实贯彻十六大精神,对建设一流大学起着十分重要的指导作用。一流大学在大学内部表现为追求卓越的目标定位、指标评定,在大学与社会关系中表现为社会的认可。目前,"综合性、研究型、开放式"的办学模式是我国创建一流大学的共同目标。在我国,要建设国际上有影响的一流大学,必须在近几年打下坚实基础。  相似文献   

Monitoring of atrazine treatment on soil bacterial,fungal and atrazine-degrading communities by quantitative competitive PCR     

Martin-Laurent F  Piutti S  Hallet S  Wagschal I  Philippot L  Catroux G  Soulas G 《Pest management science》2003,59(3):259-268

We report the development of quantitative competitive (QC) PCR assays for quantifying the 16S, 18S ribosomal and atzC genes in nucleic acids directly extracted from soil. QC-PCR assays were standardised, calibrated and evaluated with an experimental study aiming to evaluate the impact of atrazine application on soil microflora. Comparison of QC-PCR 16S and 18S results with those of soil microbial biomass showed that, following atrazine application, the microbial biomass was not affected and that the amount of 16S rDNA gene representing 'bacteria' increased transitorily, while the amount of 18S rDNA gene representing fungi decreased in soil. In addition, comparison of atzC QC-PCR results with those of atrazine mineralisation revealed that, in response to atrazine treatment, the amount of atzC gene increased transitorily in soil pre-treated with atrazine, suggesting that accelerated atrazine biodegradation in soil could be due to a transient increase in the size of the atrazine mineralising community.  相似文献