猪链球菌对红霉素耐药性的研究   总被引：2，自引：0，他引：2  

李艳华  姜成刚  蔡雪辉  童光志  刘娣  佟恒敏 《中国预防兽医学报》2006,28(3):359-362

从发病猪体内分离、鉴定猪链球菌，采用肉汤稀释法和纸片琼脂扩散法筛选对红霉素耐药的猪链球菌，用双纸片法确定耐药株的耐药表型，通过聚合酶链反应检测对红霉素耐药的基因ermb/mefA。猪链球菌对红霉素的耐药表型为cMLS表型，即同时对克林霉素耐药。在3株红霉素耐药株中扩增到ermb基因，其余未能检测到ermb或mefA基因。  相似文献   

Bringing the World to Australia - WSAVA 2007     

Dr Di Sheehan 《Australian veterinary journal》2006,84(3):N13-N13

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Validation of RT‐PCR Assays for Molecular Characterization of Porcine Teschoviruses and Enteroviruses     

G. La Rosa  M. Muscillo  A. Di Grazia  S. Fontana  M. Iaconelli  M. Tollis 《Zoonoses and public health》2006,53(6):257-265

Porcine enteroviruses (PEVs) and teschoviruses (PTVs) are described as causative agents of neurological disorders, fertility disorders and dermal lesions of swine. Difficulties in the serological detection of these viruses may lead to a significant underestimation of infections with clinical symptoms. With the recent availability of genome sequence data for all the serotypes, molecular diagnosis is a possibility. The present study describes a new approach to molecular ‘serotyping’ of PTVs and PEV‐B viruses, involving the amplification and sequencing of a genomic fragment of the VP1 coding region. A molecular characterization of Italian entero‐teschovirus isolates was performed using a set of previously published and newly designed polymerase chain reaction primers. A total of 33 porcine isolates and 10 reference strains were analysed. Porcine enterovirus‐B samples were first diagnosed as positive for enterovirus by amplification of the 5′‐non‐translated region. Samples were then typed by amplification and sequencing of a portion of the VP1 coding region. Porcine enterovirus‐A and PTVs were detected by a published assay in the 5′‐NC region that allows them to be differentiated according to the size of amplification product, using the same set of primers. For serotype characterization of PTV, we evaluated four different regions: the N terminus of the capsid protein VP2, the region encoding for RNA‐dependent RNA polymerase, and the capsid VP1 and VP4 regions. The newly designed primers in the VP1 region was proved to be broad in range and suitable for serotype assessment and therefore constitute a useful diagnostic tool for molecular diagnosis of porcine teschovirus/enterovirus strains and for the study of molecular epidemiology and evolution of these viruses.  相似文献   

Synthesis and insecticidal activities of pyridine ring derivatives of podophyllotoxin     

Xudong Di  Yanqing Liu  Hang Xiao  Rong Gao 《Pesticide biochemistry and physiology》2007,89(1):81-87

In an attempt to find the biorational pesticides, we synthesized 12 pyridinyl derivatives of podophyllotoxin (PPT) and 4′-demthylepipodophylltoxin (4′-DMEP) in this study. Their structures and the α/β substitution at C-4 were confirmed by ¹H NMR, IR, MS spectral analyses and elemental analysis. The insecticidal activities were tested against fifth-instar larvae of Pieris rapae and the third-instar larvae of Cullex pipiens pallens at concentrations of 250 and 10 μg ml⁻¹. Four derivatives of PPT, 4.1, 4.2, 4.3 and 4.5, showed higher insecticidal activities against P. rapae than PPT, while three derivatives of PPT, 4.4, 4.5 and 4.6, displayed higher mosquito larvicidal activity than PPT, with LC₅₀ values of 1.66, 3.96 and 1.54 mg l⁻¹, respectively. Interestingly, we also found that the pyridine ring derivatives of PPT showed delayed insecticidal activity, which is different from traditional neurotic insecticides. The results suggest that 4′-OCH₃ in the PPT derivatives is essential to keep the insecticidal activity and the insecticidal activities of pyridine ring derivatives of PPT are higher than that of the derivatives of 4′-DMEP, supporting PPT has the potential to be a lead structure of semi-synthetic insecticides.  相似文献   

表达猪繁殖与呼吸综合征病毒CH-1a株核衣壳蛋白重组鸡痘病毒的构建   总被引：2，自引：0，他引：2  

智海东  王云峰  张晶  王玫  刘娣  童光志 《中国预防兽医学报》2007,29(1):1-4,26

从含有猪繁殖与呼吸综合征病毒（PRRSV）核衣壳蛋白（N）的质粒扩增出N基因，构建禽痘病毒转移载体。该载体含有禽痘病毒早晚期启动子LP2EP2控制之下的PRRSVN基因、P11启动下的报告基因lacZ以及用于同源重组的禽痘病毒基因组的片段。在转移载体转染亲本病毒S—FPV-017感染的鸡胚成纤维细胞（CEF）之后，采用蓝色表型筛选的方法，筛选到表达N基因的重组病毒，并对其进行了6轮蚀斑纯化。PCR方法鉴定证明重组病毒的基因组中含有完整PRRSVN基因，间接免疫荧光试验证明了PRRSVN蛋白在重组病毒感染的CEF细胞中获得表达，本研究为猪繁殖与呼吸综合征非复制型疫苗的研制打下了基础。  相似文献   

20%咪鲜胺·异菌脲悬浮剂的高效液相色谱分析   总被引：1，自引：0，他引：1  

张健  张涛  许迪 《农药科学与管理》2007,28(9):11-14

本文采用高效液相色谱法分析20%咪鲜胺·异菌脲悬浮剂,使用C18反相柱和紫外可变波长检测器,以甲醇 水为流动相,用外标法对有效成分进行分析和定量。咪鲜胺和异菌脲标准偏差分别为0.055和0.021变异系数分别为0.53%和0.19%。平均回收率分别为98.95%和99.10%。  相似文献   

Leaf necrosis and twig dieback of sweet persimmon (Dyospiros kaki L.) caused by Pseudomonas syringae pv. syringae in Italy     

M. Scortichini  D. D'Ascenzo  Daniela Di Silvestro 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(6):625-627

In spring 1996, extensive leaf necrosis and twig dieback were observed on young sweet persimmon (Dyospiros kaki L.) trees, cultivars O'Gosho, Hachija, Mercatelli and Kaki-tipo planted in the Abruzzo region (central Italy). Many trees were killed. When the dieback reached the trunk, in many cases, new vegetation was noticed above the graft point. The cultivar Jiro-C was not affected by the disease. During 1997, no symptoms were observed on any plant. The orchard was planted in a clay soil with a very low content of organic matter. Biochemical, nutritional and pathogenicity tests indicated Pseudomonas syringae pv. syringae van Hall as the causal agent of the disease. This is the first report of this bacterium as a pathogen of sweet persimmon in Europe.  相似文献   

Small Animal Internal Medicine          下载免费PDF全文

Rocky Di Fruscia 《The Canadian veterinary journal. La revue veterinaire canadienne》1998,39(9):558

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IMAGE MAGNIFICATION IN DIGITAL FLUOROSCOPY     

Diana S.  Rosenstein  DVM  MS 《Veterinary radiology & ultrasound》1998,39(4):304-308

Image magnification is inherent in radiography. In digital fluoroscopy, the three components of magnification are geometric, electronic and photographic. In this study, the total magnification factor of a digital imaging system was determined by two methods, 1) comparison of measurements of a known object to its image and 2) calculation of geometric, electronic and photographic magnification from the imaging system specifications. Both methods were employed for various focal-film distances, image intensifier tube modes and laser printer formats. Results of these two methods were different due to the detrimental effect of penumbra on image quality with increasing magnification. If a radiographic image is to be used to approximate object size, then a technique should be used that will minimize magnification. In digital fluoroscopy this is achieved with the shortest object-film distance (assuming a fixed focal-object distance), largest image intensifler mode and greatest number of images per sheet of film.  相似文献   

我国复配食品添加剂发展现状、问题及对策     

董娇  曹宁阳  岑琴  吴迪 《农业科技与装备》2017,(1):64-65

综述复配食品添加剂的定义、分类和特点,针对我国复配食品添加剂在生产应用中存在的主要问题,提出相应的解决措施,展望复配食品添加剂在我国的发展前景,为推动复配食品添加剂产业发展提供借鉴。  相似文献