秸秆纤维素分解细菌的筛选与鉴定     

洪权春  李红雨  刘秀花 《湖北农业科学》2016,(13):3327-3330

利用纤维素琼脂选择培养基和刚果红染色方法,从不同来源的土样中分离出2个菌株,测定了其纤维素酶活性、小麦秸秆降解能力,并对纤维素降解能力强的两个菌株进行了分子鉴定。结果表明,两株高效纤维素分解菌在纤维素刚果红培养基上均能形成透明水解圈,利用16S r RNA序列测序并分析Genbank中的同源性,结合形态和理化性质确定为Bacillus thuringiensis和Bacillus anthracis。在37℃,p H为7的条件下测定了纤维素酶活力,SC1-3和XR2-5-4分别为1.41和1.59。这两株37℃下经15 d后小麦秸秆失重率达19.92%和22.83%。  相似文献   

1株奶牛源松鼠葡萄球菌的分离鉴定及耐药性分析     

田秋丰  张红  尹珺伊  刘秋瑾  张军  王岩  秦平伟  朱庆贺  苗艳  陈楠楠  张淑芬  丁昕颖  马姗姗  王振 《中国畜牧兽医》2021,48(4):1482-1488

为确定奶牛垫料中是否含有病原菌并深入了解垫料中优势生长菌的类型、耐药性及致病性等情况,本试验进行了细菌分离培养、革兰染色镜检、生化试验鉴定、16S rDNA序列分析及同源性比对、药敏试验、小鼠致病性试验。结果显示,分离菌在普通营养琼脂平板上形成圆形、表面光滑的白色菌落,血琼脂平板上形成黏稠、较大的白色菌落。革兰染色镜检结果显示,分离菌为革兰阳性,球型,呈葡萄串状排列,或单个散落。生化试验结果显示,分离菌对木糖、葡萄糖、麦芽糖、果糖、乳糖、硝酸盐还原等呈阳性反应,而蜜二糖、木糖醇、山梨醇、尿素、V-P反应等呈阴性反应。16S rDNA序列分析结果显示,扩增的16S rDNA序列长度为1 298 bp,与松鼠葡萄球菌的核苷酸同源性达99.85%~100%;系统进化树结果显示,分离菌与松鼠葡萄球菌处于同一分支。动物试验结果表明,分离菌株对试验小鼠有较强的致病性,以0.2 mL/只（7.9×10⁸ CFU/mL）菌液的剂量接种小鼠,在48 h内死亡率为60%（3/5）。药敏特性分析结果显示,分离菌株对复方新诺明、氨苄西林等7种药物敏感,对克林霉素、头孢噻肟和头孢呋辛中度敏感,对青霉素、红霉素和林可霉素耐药。本研究为奶牛源松鼠葡萄球菌的分离鉴定及防控提供了参考依据。  相似文献   

Classification of Tomicus Species     

Li Xia  Zhang Zhen  Cao Peng  Wang Hongbin  Han Pingding 《中国林业科技(英文版)》2012,(3):45-45

Both morphological characters and a portion of of 28S rDNA sequences were used to identifying Tomicus species.The specimens were classed into groups with the following characters: 1) granules or punctures on interstria 2 on the declivity of the elytra;2) length of the elytral interstrial hairs and hairs arising from punctures;3) arrangement of pronotal punctures and hairs.These characters could be clearly examined under a binocular microscope at 30×magnification and they were applicable and valuable for the forest entomologists to identify Tomicus species.The phylogenetic tree established with difference in 28S rDNA sequence of D2 region revealed that the specimens of each group identified by morphological characters were also grouped together.The genetic distances of intra-species, inter-species and inter-genus were not overlapped. Genetic divergence of 28S rDNA was also useful for identifying Tomicus species.  相似文献   

Binucleate Rhizoctonia sp. AG G causing root rot in yacon (Smallanthus sonchifolius) in Brazil     

R. C. Fenille  M. B. Ciampi  N. L. Souza  A. K. Nakatani  E. E. Kuramae † 《Plant pathology》2005,54(3):325-330

A new rot caused by a binucleate Rhizoctonia sp. affecting the tuberous root cortex of the domesticated yacon ( Smallanthus sonchifolius ) has been observed in Brazil. Isolates of a binucleate Rhizoctonia sp. were collected from roots with rot symptoms and characterized by the number of nuclei per cell, hyphal anastomosis, RAPD molecular markers, ITS-5·8S rDNA sequence and pathogenicity tests. All isolates had a mean of 1·9–2·2 nuclei per cell and anastomosed with the binucleate Rhizoctonia sp. AG G-tester strain. RAPD analysis was carried out between 11 isolates recovered from yacon and 11 AG (A, Ba, Bb, Bo, C, D, F, G, O, P, Q) standard testers of binucleate Rhizoctonia sp. Genetic similarities of 94·8–100% were observed among isolates of the binucleate Rhizoctonia sp. from yacon and all isolates were genetically more closely related to the AG G tester than other strains according to upgma analysis using RAPD markers. Homologies of complete ITS nucleotide sequences were 100% between binucleate isolates of Rhizoctonia sp. from yacon and the AG G tester. According to pathogenicity tests, the isolates caused typical rot symptoms of yacon tubers 90 days after inoculation  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   

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   

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   

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   

18S rRNA／rDNA序列分析技术在瘤胃原虫分类学研究中的应用     

钟霞  毛华明  邓卫东 《中国畜牧兽医》2007,34(12):56-58

作者指出了反刍动物瘤胃原虫分类学研究中的难点，介绍了原虫分类学中新兴的分子生物学指标(18S rRNA／rDNA序列同源性)，综述了18S rRNA／rDNA序列分析技术在瘤胃原虫分类研究中的应用。  相似文献   

斑点叉尾(鮰)嗜麦芽寡养单胞菌的分离鉴定及系统发育分析   总被引：1，自引：0，他引：1  

耿毅  汪开毓  陈德芳  黄小丽 《中国兽医学报》2007,27(3)

从发生在四川、重庆等省市的斑点叉尾(鮰)急性流行性传染病病鱼的肝脏、肾脏内分离到1株高致病性菌株(CCF00024),人工感染健康鱼表现出与自然病鱼相同的症状,并从中分离获得同种细菌,证实其为斑点叉尾(鮰)急性流行性传染病的病原菌.形态、生理生化检测表明,该菌为非发酵型直杆菌,严格需氧,革兰氏阴性,极生多鞭毛,对除麦芽糖和甘露糖以外的多种糖类不利用产酸,氧化酶阴性,DNA酶、蛋白酶、脲酶、赖氨酸脱羧酶阳性,MR、VP阴性.在以该菌16S rDNA序列(GenBank登录号AY970826)和GenBank及RDP数据库内同源性较高的细菌16S rDNA序列构建的系统发育树中,分离菌CCF00024与嗜麦芽寡养单胞菌(Stenotrophomonas maltophilia)聚在一簇,特别是与S.maltophilia M5-1的同源性最高,序列相似性达99.6%,结合形态和生理生化特点将其鉴定为嗜麦芽寡养单胞菌(Stenotrophomonas maltophilia).药敏试验结果表明,对磺胺甲(口恶)唑、磺胺异(口恶)唑、阿齐霉素、洛美沙星高度敏感,而对新霉素、卡那霉素、氨苄青霉素,头孢唑啉、先锋霉素V和链霉素不敏感.  相似文献