Tomato spotted wilt virus triggers specific and shared defense mechanisms in hypersensitive and susceptible Solanaceae hosts     

Vera Quecini  Mrio L. Lopes  Flvia T.H. Pacheco  Maria das G. Ongarelli 《Physiological and Molecular Plant Pathology》2007,70(4-6):189-197

In situ and in vitro techniques were employed to investigate the metabolic changes caused by Tomato spotted wilt virus in hypersensitive and susceptible hosts; Petunia hybrida and Nicotiana tabacum, respectively. In petunia, H₂O₂ accumulation preceded increased peroxidase and shikimate dehydrogenase activity at local lesion sites. In systemic tobacco plants, peroxidase activity was induced prior to symptom onset and the activity of shikimate dehydrogenase was disrupted upon viral infection. Taken together, our data suggest that reactive oxygen species-based mechanisms of defense are shared by hypersensitive and susceptible hosts, although downstream components and regulatory mechanisms are distinct.  相似文献   

Absence of strictly age-related resistance to Mycoplasma hyosynoviae infection in 6-week-old pigs     

Lauritsen KT  Hagedorn-Olsen T  Friis NF  Lind P  Jungersen G 《Veterinary microbiology》2008,130(3-4):385-390

Mycoplasma hyosynoviae has never been reported to cause arthritis in pigs younger than 10 weeks of age. In order to investigate whether a strict age-related resistance exists, four 6-week-old pigs and four 13-week-old pigs, all immunologically na?ve with respect to M. hyosynoviae, were inoculated intranasally with the agent and autopsied at day 11 or 13 after infection. One uninoculated pig per age group was included as a negative control. Just as the 13-week-old pigs, the 6-week-old piglets were susceptible to blood, joint and tonsillar infection with M. hyosynoviae and developed clinical arthritis following inoculation with the agent. Thus, we found no evidence of an age-related resistance to the infection.  相似文献   

香蕉品种对枯萎病菌感病性与对病菌毒素敏感性之间的相关性   总被引：1，自引：0，他引：1  

杨秀娟  杜宜新  陈福如  甘林  阮宏椿 《果树学报》2010,(1)

为明确香蕉品种对香蕉枯萎病菌感病性与对病菌粗毒素敏感性之间的相关性,采用根部病菌孢子接种测定了36份香蕉品种苗对香蕉枯萎病菌4号生理小种的感病性,以及采用植株根部和叶片毒素处理测定了5份香蕉品种苗对病菌粗毒素的敏感性。结果表明,天宝角蕉(AAA)、柴蕉(AAA)、广粉1号(AAB)和贡蕉(AA)表现抗病,哥斯达黎加蕉(AAA)和抗枯5号(AAA)表现中抗;感病品种对毒素的敏感性高于抗病品种。通过香蕉不同品种的病情指数、萎蔫指数和叶片损伤面积的差别分析,发现香蕉苗期对枯萎病菌感病性与对病菌粗毒素敏感性之间存在正相关性,60d龄期的假植苗病情指数与其叶片损伤面积之间存在显著的正相关性。因而叶片毒素处理法测量香蕉假植苗中部叶片损伤面积可作为一种快速区别香蕉抗病能力的有效方法。  相似文献   

白肋烟青枯菌的分离鉴定及药敏性研究   总被引：1，自引：1，他引：0  

李洪  严占勇  杨水英  吴卫玲  王晗  李振轮 《安徽农业科学》2011,39(34):21082-21084

[目的]分离鉴定白肋烟青枯菌并测定该菌对6种杀菌剂的药敏性。[方法]采用半选择培养基（PCCG）和聚合酶链式反应（PCR）技术相结合的方法,对四川省达州市白肋烟茎秆中的青枯菌进行分离,并对其生化型进行了鉴定;通过药敏试验,研究了所得青枯病菌在实验室条件下对叶枯唑、乙蒜素、农用硫酸链霉素、石硫合剂、47%聚赖氨酸、99%曲酸6种杀菌剂的敏感性。[结果]共分离得到23株青枯菌,均为生化Ⅲ型。分离所得青枯菌株对乙蒜素、农用硫酸链霉素、叶枯唑较为敏感,其中乙蒜素对烟草青枯病菌有良好的防治效果,其EC50为0.086 ml/L。[结论]为白肋烟青枯病的防治提供了理论依据。  相似文献   

兔支气管败血波氏杆菌的分离与鉴定     

李长安  方艳琴  陈晓霖  张耀相 《西北农业学报》2011,20(10):16-19

对陕西商洛某养殖场病死兔解剖、无菌采取病料,从病料中分离到1株革兰阴性小杆菌,经生物学特性试验和生理生化试验鉴定,为兔支气管败血波氏杆菌.药敏试验结果表明,该分离菌株对环丙沙星、氟哌酸、氧氟沙星等抗生素高度敏感;对氯霉素、红霉素、四环素等抗生素耐药.外毒素试验和动物致病性试验对小白鼠均有致病作用.  相似文献   

Comparison of acetylcholinesterase from three field populations of Liposcelis paeta Pearman (Psocoptera: Liposcelididae): Implications of insecticide resistance     

Yi Ren  Xue-Qin Wei  Shuang Wu  Wei Dou  Jin-Jun Wang   《Pesticide biochemistry and physiology》2008,90(3):196-202

The toxicological and biochemical characteristics of acetylcholinesterases (AChE) in Liposcelis paeta Pearman were investigated in three field populations collected from Nanyang city of Henan Province (NY), Wuzhou (WZ) and Hezhou (HZ) Cities of Guangxi Province, China. The result of bioassay showed that the LC_50s of the NY (281.4802 mg/m²) and the WZ (285.0655 mg/m²) to dichlorvos were 1.156-fold and 1.171-fold higher than that of the HZ (243.5197 mg/m²), respectively. Compared to NY population, the activity per insect and the specific activity of AChE in WZ and HZ populations were significantly higher, and significant kinetic differences among the three populations were also observed. The apparent Michaelis–Menten constant (K_m) for acetylthiocholine iodide (ATChI) was obviously lower in NY than that in WZ and HZ populations, indicating a higher affinity to the substrate ATChI in the NY population. The affinity to the substrate ATChI between WZ and HZ population was also significantly different. As for V_max, the values of WZ and HZ populations were significantly greater when compared to that for NY population, suggesting a possible over expression of AChE in the former two populations. The inhibition studies of AChE indicated that paraoxon-ethyl, demeton-S-methyl, carbaryl, and eserine all possessed some inhibitory effects on AChE in L. paeta. The results of I_50S suggested that when compared to the other two populations, while AChE from HZ population was less sensitive to paraoxon-ethyl and demeton-S-methyl. The contradiction with the result of the bioassay might be due to the different insecticides used in the bioassay. Although both carbaryl and eserine had excellent inhibitory effects, there was no significant difference among the three populations. The statistical analysis of the bimolecular rate constants (k_i) was consistent with the above situation that carbamates expressed remarkable inhibitory effects. It was noticeable that NY population was most sensitive to carbaryl while least to eserine. The differences in AChE among three populations may attribute to the difference in control practices for psocids between Henan and Guangxi Provinces.  相似文献   

Synergism of resistance to phosalone and comparison of kinetic properties of acetylcholinesterase from four field populations and a susceptible strain of Colorado potato beetle     

M. Malek Mohamadi  M.S. Mossadegh  M.T. Goodarzi  H. Galehdari 《Pesticide biochemistry and physiology》2010,98(2):254-262

The susceptibility to phosalone and biochemical characteristics of acetylcholinesterase (AChE) were compared between susceptible (SS) strain and four field populations of Colorado potato beetle (CPB) collected from commercial potato fields of Hamedan Province in west of Iran. Bioassays involving topical application of phosalone to fourth instars revealed up to 252 fold resistance in field populations compared with the SS strain. Synergism studies showed that although esterase and/or glutathione S-transferase metabolic pathways were present and active against phosalone, they were not selected for and did not have a major role in resistance. It is likely that piperonyl butoxide (PBO) reduced phosalone toxicity by inhibiting bio-activation of phosalone. The affinity (K_m) and hydrolyzing efficiency (V_max) of AChE to selected substrates, namely, acetylthiocholine iodide (ATC), propionylthiocholine iodide (PTC), and butyrylthiocholine iodide (BTC) were examined. AChE inhibition by higher substrate concentration was evident only in the SS strain. In resistant field populations, Aliabad (Aa), Bahar (B) and Dehpiaz (Dp), substrate inhibition at higher concentrations was not seen. There was no definite optimal concentration found for any of the substrates examined. When ATC, PTC, and BTC were used as substrate, the reaction rates of AChE from Yengijeh (Yg) population increased as the concentration of all three substrates were increased, but were almost constant at concentration of ATC ? 3.98, PTC ? 2.8, and BTC ? 5 mM. The susceptible form of AChE had the most efficient ATC hydrolysis but very low BTC hydrolysis activity. In contrast, AChEs from field populations elicited relatively reduced ATC hydrolysis, but relatively increased BTC hydrolysis. The in vitro inhibition potency of some organophosphates (OPs), on AChEs of the field populations and SS strain was determined. The rank order from the most potent inhibitor to the least as determined by their bimolecular reaction constants (K_i) was ethyl paraoxon > diazoxon > methyl paraoxon for AChE from Aa, B, Dp, and Yg populations, respectively, whereas the rank order for the susceptible strain was methyl paraoxon > ethyl paraoxon > diazoxon.  相似文献   

Predicting the population dynamics of three understory broad-leaved evergreen species under the influence of Sika deer in primary and secondary forests of mid-western Japan     

Hiromitsu Kisanuki  Mafumi Nakasu  Arisa Nakai  Yutaka Yurugi 《Journal of Forest Research》2008,13(1):52-58

We examined the population dynamics of three broad-leaved tree species with different susceptibilities to deer predation. Simulation analysis was conducted using a size-structured matrix model for a primary forest plot (PP) and a secondary forest plot (SP) with 56% and 12% evergreen conifer composition in the canopy, respectively. In both plots, populations of Neolitsea sericea, a species that is susceptible to deer predation, initially declined significantly but eventually leveled off. The number of small stems decreased, while that of larger stems increased, indicating that the population dynamics of N. sericea are strongly affected by browsing pressure and that the number of large trees is important for population maintenance. When we examined two deer-resistant species, Pieris japonica and Illicium anisatum, the population of P. japonica increased in the SP and decreased in the PP, whereas that of I. anisatum increased in both plots, likely because mortality tends to increase in persistently dark environments. No significant difference was observed between the present and predicted size distributions of resistant species in the PP. Competition for resources is expected to intensify in the SP as a result of the predicted increase in large stems of the resistant species I. anisatum. Therefore, a specific conservation and management strategy for tree species should be considered for each forest type under the influence of Sika deer.  相似文献   

黄金鲫温和气单胞菌鉴定及溶血素基因检测   总被引：1，自引：0，他引：1  

梁利国  马昕羽  谢骏 《水生态学杂志》2013,34(5):76-81

采用常规的培养特征、理化特性及分子生物学的方法,从患病的黄金鲫体内分离到的优势菌YD-1进行了回感试验、表观生物学、药敏试验及毒力因子检测等系统性研究。结果表明,该菌在盐度1-3%、PH4-9,温度10-30℃的营养肉汤培养基中均能生长。该菌株16S rRNA基因序列（GenBank收录号: KC561935, 长度1446bp）和gyrB基因序列（GenBank收录号: KC561934, 长度1169bp）分别与其他气单胞菌属细菌的基因同源性相思似在97%-99%之间,构建系统发育树确定该菌株为温和气单胞菌(Aeromonas sobria)。人工回感试验可引起健康银鲫死亡。对该菌毒力因子进行检测,可扩增出溶血素基因片段。药敏试验显示：该菌对多粘菌素、头孢呋辛、米诺环素、复达新、菌必治、新霉素等6种药物敏感。  相似文献   

草鱼(Ctenopharyngodon idellus)性腺细胞系(GCO)特性和对鲤春病毒的敏感性          下载免费PDF全文

王津津  刘莹  于力  贾鹏  陈兵  史秀杰  郑晓聪  兰文升  何俊强  刘荭 《渔业科学进展》2016,37(6):56-61

草鱼(Ctenopharyngodon idellus)性腺细胞系(GCO)是中国科学院水生生物研究所在20世纪70年代开展草鱼出血病研究时建立的一株细胞系,迄今已传至300多代,在中国鱼类病毒学研究领域发挥了重要作用.本研究采用形态学观察、细胞生长曲线测定、细胞周期测定、细胞核型分析、细胞凋亡检测、电镜观察等方法,对GCO的生长特性及鲤春病毒血症病毒(SvCv)在该细胞中的增殖特性等进行了研究.结果显示,GCO细胞的最适生长温度为25℃,在M199和MEM等细胞培养液中均能较好地生长,培养液中最适的胎牛血清浓度为10％.测定了GCO细胞系对SVCV病毒的敏感性,发现与鲤(Cyprinus carpio)上皮瘤细胞系(EPC)、肥头鲤(Pimephales promelas)细胞系(FHM)、大鳞大麻哈鱼(Oncorhynchus tshawytscha)胚胎细胞系(CHSE-214)等世界动物卫生组织(OIE)推荐和各检测实验室常用的鱼类细胞系相比,GCO细胞系对SVCV表现出非常高的敏感性.生长盐线、电镜观察和凋亡实验显示,SVCV能引起GCO细胞系出现明显而稳定的细胞病变,引起GCO细胞系出现凋亡,并在细胞质中大量增殖.结果表明,GCO细胞系适用于SVCV病毒的分离、检测以及病毒致病性的有关研究.GCO细胞的适宜生长温度为15-28℃,这一特点将使它可以广泛地用于多种水生动物病毒的分离.  相似文献