The exploitation of the genome in the search for determinants of virulence in Streptococcus uberis     

Leigh JA  Ward PN  Field TR 《Veterinary immunology and immunopathology》2004,100(3-4):145-149

Despite much success in the control of mastitis in dairy cattle, intramammary infection with Streptococcus uberis remains a threat to herd health. This organism is a frequent cause of mastitis worldwide. Recent advances in the ability to genetically manipulate this bacterium, coupled to the determination of a representative genome sequence have already enabled the investigation of certain aspects of disease pathogenesis. Further use of such technology coupled to reliable models of disease and post-genomic analysis will permit the elucidation of further interactions between pathogen and host. This additional information can be usefully targeted at identification of candidates for inclusion in effective vaccines. This communication reviews the current, reported progress using this technology for S. uberis.  相似文献   

Changes in blood and milk lymphocyte sub-populations during acute and chronic phases of Staphylococcus aureus induced bovine mastitis     

Grönlund U  Johannisson A  Persson Waller K 《Research in veterinary science》2006,80(2):147-154

Staphylococcus aureus (S. aureus) often causes long-lasting chronic sub-clinical udder infections in dairy cows. To investigate if this can be due to a negative impact of S. aureus on lymphocytes important for the immune defence, alterations in proportions and expression intensity of CD4+, CD8+, WC1+, B and IL-2R+ lymphocytes was studied in blood and milk, as S. aureus mastitis developed from acute clinical to chronic sub-clinical form. Six healthy dairy cows were inoculated with S. aureus in one udder quarter per cow, and one quarter per cow acted as an uninfected control. Blood samples, and milk samples from infected and non-infected quarters were collected before infection and for five weeks after infection. All infected quarters developed acute clinical mastitis, of which five turned into chronic sub-clinical mastitis. In infected quarters, the proportions of all lymphocyte sub-sets, except WC1+ cells, differed in acute phase compared to pre-infection, while the dominant finding in the chronic phase was increased expression intensities per cell. An impact on blood lymphocytes and milk lymphocytes in non-infected quarters also occurred, mainly during the chronic phase. The most prominent finding was the increased proportion and expression of B-lymphocytes in blood, infected and non-infected quarters during chronic sub-clinical mastitis. As S. aureus can invade and survive intracellularly, a preferential stimulation of B-cells, suggesting development of a humoral response, may not be sufficient to eliminate intracellular bacteria, which could explain the persistence of the infection.  相似文献   

Concepts of plant health – reviewing and challenging the foundations of plant protection     

T. F. Döring  M. Pautasso  M. R. Finckh  M. S. Wolfe 《Plant pathology》2012,61(1):1-15

Plant health is a frequently used but ill‐defined term. However, there is an extensive literature on general health definitions and health criteria in human medicine. Taking up ideas from these philosophical debates, concepts of plant health are reviewed and a framework developed to locate these concepts according to their position in several philosophical controversies. In particular, (i) the role of values in defining plant health in a naturalist versus a normativist approach; (ii) negative and positive definitions of plant health; (iii) reductionist versus holistic perspectives; (iv) the focus on functionality versus resilience, i.e. the ability of the plant to perform under stress with or without human interference; (v) materialist versus vitalist approaches; and (vi) biocentric versus anthropocentric views, are surveyed. The ways in which these perspectives relate to mainstream and alternative approaches to plant protection are explored and we suggest how the contradicting views might be reconciled. It is argued that none of these perspectives is without inherent contradictions, but that by combining contrasting approaches it is possible to provide a comprehensive though fuzzy concept. Rather than giving a new definition of plant health, a conceptual framework is developed that suggests what questions may be answered in debates on plant health issues and how such debates could be organized.  相似文献   

肿节风炭疽病病原学研究及其对药材质量的影响     

蒋妮  唐美琼  蓝祖栽  黄永才  林杨  白隆华 《植物保护》2012,38(4):83-88

为明确肿节风炭疽病的致病菌及其生物学特性,研究病害发生后对药材质量的影响,采用柯赫氏法则验证菌株致病性,根据菌株的形态特征及ITS序列分析进行病原菌鉴定;参照2010年《中国药典》HPLC方法测定肿节风主要活性成分异嗪皮啶的含量。结果表明:肿节风炭疽病的病原菌为Colletotrichum dematium,肿节风为其新记录寄主。病原菌菌丝生长及产生孢子的适宜温度为24～28℃,pH值为5～9;肿节风炭疽病病情指数达到50～60时植株鲜重显著降低,当病情指数达到60～70时异嗪皮啶含量开始显著下降;表明肿节风炭疽病发生到一定程度时,会造成药材质量下降,田间病害病情指数大于60时,药材不适宜应用。  相似文献   

河南省小麦根腐线虫病的发生危害及病原鉴定     

王振跃  施艳  李广帅  崔娟  杜娟  李洪连 《植物保护学报》2012,39(4):297-302

为明确河南省小麦根腐线虫病的发生危害情况及其病原线虫种类,对14个县(市)45个采样点小麦根腐线虫进行了分离调查,分别通过人工接种测定其致病性和杀线剂处理研究其危害性,并采用形态学和分子生物学方法鉴定其病原。结果显示:小麦根腐线虫在河南省的分布具有一定的区域性,中北部的10个县(市)34个沙质土壤采样点均分离出小麦根腐线虫,而在南部土壤粘重地区的小麦根内和土壤中均没有分离出根腐线虫;15%涕灭威颗粒剂处理土壤后小麦的穗粒数、千粒重和单位面积产量较对照明显上升,产量增加13.6%;该线虫能够侵染小麦,并明显抑制小麦生长;河南省小麦根腐线虫以敏捷短体线虫Pratylenchus agilis为主。  相似文献   

富平奶山羊临床型乳房炎病原菌的分离鉴定   总被引：1，自引：0，他引：1  

李守杰  王桂英 《贵州农业科学》2012,(8):148-150

为探明奶山羊感染乳房炎病原菌的情况,为其防治提供参考,对富平县3个不同乡镇的79头患病奶山羊和118份奶样进行分离鉴定。结果表明:样品中共检测出革兰氏阴性杆菌、革兰氏阳性杆菌、革兰氏阳性球菌和真菌4类病原菌,分离出7种、126个菌株。其中,大肠杆菌36株,占28.5%;金黄色葡萄球菌28株,占22.2%;绿脓杆菌23株,占18.3%;链球菌21株,占16.7%;变形杆菌8株,占6.3%;蜡样芽孢杆菌6株,占4.8%;酵母菌4株,占3.2%。结论:大肠杆菌、金黄色葡萄球菌、绿脓杆菌、链球菌是富平县奶山羊乳房炎的主要致病菌。  相似文献   

陕西及宁夏盐渍土中拮抗放线菌资源研究     

王海利  来航线  马玥  费关键 《西北农业学报》2012,21(5):54-59

以分离自盐渍土中的放线菌作为供试菌株,以养殖业中常见的9种动物病原菌作为靶标菌进行拮抗放线菌研究,并对4株优良拮抗菌株进行初步鉴定。结果表明,供试的1 172株放线菌主要以链霉菌属为主,占到88.82%,有拮抗活性的菌株551株,占到47.01%;供试放线菌对不同靶标菌的抑菌作用差异较大,对金黄色球菌和无乳链球菌拮抗效果较好;菌株01F10为白孢类群,与Streptomyces qinglanensis亲缘关系最近,序列相似度为99.11%;菌株02H13和14H03为粉红孢类群,与Streptomyces gobitricini序列相似度达到100%;菌株07F10为灰褐类群,与Streptomyces sparsus亲缘关系最近,序列相似度为99.69%。  相似文献   

福建省烟草灰霉病的发生与病原鉴定   总被引：3，自引：0，他引：3  

邓真  顾钢  张绍升 《亚热带农业研究》2012,(3):164-168

观察并记述了福建省烟草灰霉病的发生特点和病害症状。结果表明,烟草灰霉病的病原鉴定为灰葡萄孢(Botrytis ci-nerea),接种实验表明该病原菌具有很强的致病力,可以侵染叶片和茎部,致整株烟苗枯萎死亡。  相似文献   

A Resistance Bioassay for Rhizoctonia Root and Crown Rot and Damping-off Caused by the Anastomosis Groups AG 2-2111B and AG 4 in Sugar Beet     

Carlos Berdugo  Christian Hillnhiitter  Richard Sikora  Erich-Christian Oerke 《农业科学与技术》2012,(3):294-302

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红掌细菌性叶斑病的病原鉴定     

周翠  孟凡志  何邦令  刘会香 《山东农业大学学报(自然科学版)》2012,43(1):24-27

本文对山东济南商河保护地红掌上发生的1种细菌性病害进行了病原鉴定。通过对红掌上分离的病原细菌进行形态观察、染色试验、致病性测定、生理生化性状等常规细菌鉴定技术,结合细菌16S rDNA序列分析,鉴定该红掌细菌性叶斑病的病原菌为黄单胞菌属地毯草黄单胞菌柑橘致病变种(Xanthomonas axonopodis pv.cit-ri)。  相似文献