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161.
解淀粉芽孢杆菌B1619脂肽类抗生素的分离鉴定及其对番茄枯萎病菌的抑制作用 总被引:2,自引:0,他引:2
【目的】从解淀粉芽孢杆菌(Bacillus amyloliquefaciens)生防菌株B1619发酵液上清中分离脂肽类抗生素,分析其抑菌活性相关成分,为应用解淀粉芽孢杆菌B1619菌株防控番茄枯萎病提供依据。【方法】利用特异性引物对B1619中3种脂肽类抗生素合成相关基因sfp、ituA和fenB进行检测;通过盐酸沉淀、甲醇抽提法等方法提取脂肽类抗生素粗提物;用SupelcleanTM LC-18柱及PHASE HF-NH2柱对3种脂肽类抗生素粗提物进行分离;通过MALDI-TOF-MS和HPLC分析、鉴定3种脂肽类抗生素;采用平板对峙培养分别测定3种脂肽类抗生素粗提物对番茄枯萎病菌(Fusarium oxysporum f.sp.lycopersici)的抑菌活性。【结果】从解淀粉芽孢杆菌B1619的基因组DNA中扩增sfp、ituA和fenB等脂肽类抗生素合成基因,扩增产物经克隆、测序分析,表明B1619菌株中含有这3个基因。通过HPLC分析,发现60%甲醇洗脱液分离物分别在12、16.5、18 min处出现相应峰值,保留时间与bacillomycin L标准品一致,分泌量为18.5 mg·L-1;70%甲醇洗脱液分离物分别在22、34、37、51及53 min处出现相应峰值,保留时间与fengycins标准品一致,分泌量为5.1 mg·L-1;100%甲醇洗脱液分离物分别在27、37、41、51及53 min处出现相应峰值,保留时间与surfactins标准品一致,分泌量为74.3 mg·L-1。经液质联用进一步验证分析3种脂肽类抗生素的质子化峰值,60%甲醇洗脱液分离物峰值范围在m/z=1 043.4、1 057.5和1 071.4 Da,是C13-C15的bacillomycin L;70%甲醇洗脱液分离物峰值范围在m/z= 1 463.9、1 477.9、1 491.9和1 505.9 Da,是C15-C17的fengycins;100%甲醇洗脱液分离物峰值范围在m/z=1 008.6、1 022.7和1 036.7 Da,是C13-C15的surfactins。平板对峙法试验结果表明1 mg·mL-1 bacillomycin L和fengycins对番茄枯萎病菌有较强的抑菌效果,而1 mg·mL-1surfactins对番茄枯萎病菌的抑菌活性较弱,再将surfactins的浓度提高至3和6 mg·mL-1,发现其抑菌效果没有明显变化。【结论】B1619菌株分泌3种脂肽类抗生素,其中对番茄枯萎病菌生长起重要抑制作用的抗生素是bacillomycin L和fengycins,surfactins对番茄枯萎病菌的抑制活性较弱。 相似文献
162.
探讨了卡那霉素 (Kan)、羧苄青霉素 (Cb)、头孢霉素 (Cef)和氨苄青霉素 (Amp) 4种抗生素对台湾青枣幼嫩茎段和疏松的愈伤组织生长的影响 ,初步确立了对台湾青枣 (ZiziphusmauritianaLam .)进行农杆菌介导的遗传转化研究中的抑菌和转化体的筛选策略 .Kan 75mg·L-1时 ,5 0d后茎段基本停止生长并开始变成白色 (白化 ) ;Kan2 5mg·L-1时 ,胚性愈伤组织生长受到明显的抑制 ,Kan 5 0mg·L-1时 ,其生长基本停止且开始褐变 ,Kan 75mg·L-1以上时胚性愈伤组织完全变褐 .适当浓度的Cb或Cef对芽的伸长生长有一定的促进作用 ,Cb +Cef却对芽的伸长出现轻微的抑制效应 .Amp对茎段生长有抑制作用 相似文献
163.
细菌耐药机理及控制对策研究进展 总被引:5,自引:0,他引:5
随着抗菌药物的广泛应用,越来越多的细菌出现耐药性,而且耐药水平也越来越高。耐药性呈全球发展趋势,极大地影响着食品安全,危害着人类身体健康,本文就近年来国内外对细菌的耐药机理,耐药性的传播及对耐药性的控制对策等方面的研究进展作了阐述和综述。 相似文献
164.
内生菌螺旋毛壳Chaetomium spirale ND35是一株广谱拮抗性生防因子。为了阐明菌株ND35抗生素在植物病害生物防治中的作用机制,系统研究了抗生素的产生、提取纯化及其在离体和温室条件下的抑菌防病作用。菌株ND35的发酵液经乙酸乙酯萃取,浓缩得黄褐色抗生素粗提液。平皿抑菌试验表明,抗生素粗提液对20余种植物病原真菌有抑制作用,浓度为400μg/mL时对病菌菌丝生长的抑制率范围从14.4%到72.6%。浓度为500μg/mL和1000μg/mL的抗生素粗提液对新月弯孢分生孢子萌发的抑制率分别是54.2%和75.9%。发酵时间也影响抗生素的产量,马铃著葡萄糖液体培养基中发酵15天时,抗生素产量最高。经薄层层析和高效液相色谱检测,证明有两个活性组分。温室试验表明,该抗生素粗提液稀释50倍液对玉米弯孢叶斑病的防治效果可达85.5%,稀释250倍液防治效果达63。3%。试验结果表明,抗生素是菌株ND35重要的生防决定因子之一,抗生素粗提液也展示了对玉米弯孢叶斑病具有较好的生防潜能。 相似文献
165.
Nucleotides and carob pulp were tested as possible alternatives to antimicrobial growth promoters for newly weaned pigs. Four dietary treatments were used: basal diet, nucleotides, carob pulp and nucleotides + carob pulp. Performance was measured in a group of 72 pigs. Another group of 60 pigs was used for histological measurements of the jejunal mucosa and microbiological measurements by RFLP in ileum and caecum at different post-weaning intervals. Treatment did not affect performance. On the other hand, the morphology parameters of the jejunum were significantly (P < 0.001) affected by day after-weaning. No effects (P > 0.05) of treatment were observed on these parameters. The similarity (intra and inter-group) of the intestinal microbiota decreased with day after-weaning (P < 0.001) and was also affected by dietary treatment (P < 0.05). The nucleotide diets had the highest similarities in the ileum whereas the carob pulp diets had the lowest in the caecum. It is concluded that both nucleotides and carob pulp are able to modulate the changes in microbiota composition after weaning and that whereas nucleotides act in the ileum, carob pulp acts in the caecum. 相似文献
166.
The effects of feeding benzoic acid on weanling pig performance and on the ecology of their gastrointestinal microbiota were evaluated. One hundred and forty-four piglets (4 weeks of age) were used. Half of the piglets were fed a control diet and half were fed the same diet with 0.5% benzoic acid, and their performance was measured for 28 days. At the end of the trial, twelve piglets from each treatment were euthanised and samples of ileal and caecal digesta were collected. The digesta samples were cultured to quantify Lactobacillus spp., Escherichia coli,Enterococcus spp. and Clostridium perfringens and they were also studied by restriction fragment length polymorphism to evaluate the biodiversity degree and the similarity between the profiles of the microbiota. Benzoic acid improved piglets’ performance, and this was associated with a greater ileal microbiota biodiversity. 相似文献
167.
168.
169.
Transference of Dietary Veterinary Drugs into Eggs 总被引:1,自引:0,他引:1
Twelve veterinary drugs, bacitracin (BC), chloramphenicol (CAP),chlortetracycline (CTC), oxytetracycline (OTC), tylosin (TS), amprolium (APL), furazolidone (FZD), nicarbazine (NCZ), ormetoprium (OMP), sulfadimidine (SDD), sulfadimethoxine (SDM) and sulfamonomethoxine (SMM) were fed to laying hens for 14 days, each at a dietary concentration of 500 mg/kg. The concentrations of the drugs in the eggs from these birds were determined at 2-day intervals for 14 days after the start of feeding. The relationship between the concentrations of the drugs (mg/kg) in the eggs and the number of days after the start of feeding was analysed by regression and covariance analyses. The concentrations of the drugs in the eggs became constant after 4 days for OTC, TS, FZD and all the sulfonamides, and after 6 days for CAP, APL, NCZ and OMP. No BC or CTC was detected in the eggs. The transfer rates of the 10 drugs (excluding BC and CTC) from the feed to eggs varied from 0.005% for TS up to 1.540% for SDD. 相似文献
170.
P. Roumagnac L. Gagnevin O. Pruvost 《European journal of plant pathology / European Foundation for Plant Pathology》2000,106(9):867-877
Onion bacterial blight, caused by Xanthomonas sp., is a potentially severe disease in several tropical and subtropical areas. Although little research has been undertaken on this pathosystem, seed transmission of the pathogen has been hypothesized. Because of an important bacterial microflora naturally associated with onion seeds, detection of the pathogen is difficult using non-selective agar media. A new semi-selective medium, whose selectivity was obtained by a combination of four antibiotics, was developed. The new NCTM1 medium contained (per liter) yeast extract 7g, peptone 7g, glucose 7g, agar 15g, neomycin 10mg, cephalexin 30mg, trimethoprime 3mg, pivmecillinam 100mg and propiconazole 20mg. Plating efficiencies, using 16 pure cultures of the pathogen, ranged from 79% to 142%, with an average of 110% compared to the basal medium. All onion Xanthomonas sp. strains from several countries grew on NCTM1 medium. The pathogen was repeatedly isolated using this medium from seed samples containing approximately 106 saprophytic bacteria per gram, as well as from symptomless plant material. Xanthomonas sp. was detected only in seeds originating from one infected seed production site. This is the first report of selective isolation of Xanthomonas sp. from onion seeds. NCTM1 medium should be a valuable tool to study the ecology and epidemiology of Xanthomonas sp. causing onion bacterial blight. 相似文献