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乳酸菌素基因PlnE和PlnF在大肠杆菌中的异源表达 总被引:2,自引:2,他引:0
为获得高产量纯品植物乳杆菌素PlnE和PlnF,研究其开发生物兽药的可能,试验通过人工合成植物乳杆菌素基因PlnE和PlnF,构建表达载体pGEX-4 T-E和pGEX-4T-F,经IPTG诱导表达条件优化后,进行亲和层析纯化融合表达蛋白,并使用SDs-PAGE进行鉴定.试验结果表明,pGEX-4T-E和pGEX-4T-F构建成功,纯化后获得2种产量高达30%的纯品融合蛋白,SDS-PAGE鉴定两融合蛋白表达正确.说明PlnE和PlnF基因片段编码的多肽能在原核细胞中正确表达,为进一步研究该细菌素的生物活性奠定了基础. 相似文献
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为获得高产量纯品植物乳杆菌素PlnE和PlnF,研究其开发生物兽药的可能,试验通过人工合成植物乳杆菌素基因PlnE和PlnF,构建表达载体pGEX-4T-E和pGEX-4T-F,经IPTG诱导表达条件优化后,进行亲和层析纯化融合表达蛋白,并使用SDS-PAGE进行鉴定。试验结果表明,pGEX-4T-E和pGEX-4T-F构建成功,纯化后获得2种产量高达30%的纯品融合蛋白,SDS-PAGE鉴定两融合蛋白表达正确。说明PlnE和PlnF基因片段编码的多肽能在原核细胞中正确表达,为进一步研究该细菌素的生物活性奠定了基础。 相似文献
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在发展中国家,食源性致病菌与大多数的食品污染有关。同时,此类细菌还会污染包括雏鸡在内的多种家禽制品。目前,人们对雏鸡消化道内的β-抵御素及其作用功效还知之甚少。荷兰乌特勒支大学兽医学院传染病学和免疫学系针对雏鸡β-抵御素gallinacin-6(Gal-6)的表达及其抗食源病原活性进行了研究。他们采用RT—PCR的方法,在食道中检测到大量表达的Gal-6mRNA, 相似文献
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旨在分离枯草芽孢杆菌及其所产细菌素,并分析重组表达后的细菌素的抑菌活性和稳定性。通过牛津杯扩散法筛选羊驼粪便中高产细菌素的芽孢杆菌;借助16S rRNA鉴定分离菌;采用硫酸铵沉淀、氯仿抽提、SDS-PAGE、质谱分析等技术获得细菌素的氨基酸序列;利用大肠杆菌表达系统对细菌素进行体外表达,并利用牛津杯扩散法测定其抑菌活性和稳定性。结果显示,分离菌是一种枯草芽孢杆菌,命名为枯草芽孢杆菌SXAU18,其可产生抑制金黄色葡萄球菌、表皮葡萄球菌、藤黄微球菌和单增李斯特菌生长的细菌素;枯草芽孢杆菌SXAU18所产细菌素可能是分子量为10~20 ku的DarA蛋白和两种未知蛋白,属于类细菌素的范畴,将未知蛋白分别命名为BLIS SXAU181和182;经原核表达的BLIS SXAU181和182主要以可溶性上清蛋白形式表达,纯化后为单一条带;重组BLIS SXAU181蛋白没有抑菌活性,重组BLIS SXAU182蛋白具有良好的抑菌活性,且具有耐高温、耐酸碱、耐人工胃液和肠液的的特性。综上,本研究从枯草芽孢杆菌SXAU18分离到具有抑制革兰阳性菌生长活性的细菌素,且重组表达后的BLIS SXAU18... 相似文献
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寻求枯草菌素Subticin 112产生的最佳发酵参数,阐明不同发酵基质对细菌素产生规律的影响,同时最大限度减少有机氮源,为细菌素的分离纯化减少工序和成本,从而为Subticin 112的高效生产提供理论依据。利用响应面法中的部分因析设计(FFD)与中心组合试验(CCD)相结合,确定发酵基质中各组分最适宜配比;比较不同发酵基质对菌体生物量、细菌素效价、比生产速率、比生长速率的影响。结果表明:发酵基质中有机氮源含量降低了74.3%,总氮源含量降低了56%,细菌素活性提高了170%,相当于青霉素当量163.8 mg/L。细菌素最大比生产速率提高了184%。证实了微量元素锰与Subticin 112的产量有密切关系,Subticin 112以菌体的混合代谢模式产生。 相似文献
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M A Valvano 《Veterinary microbiology》1992,32(2):149-161
Thirteen avian septicemic isolates of Escherichia coli were examined for the presence of the aerobactin iron transport system. All of the strains possessed a functional aerobactin system and hybridization experiments showed that the aerobactin genes were located on ColV-type plasmids in all cases. The expression of the aerobactin receptor IutA was also studied by determining the bacterial susceptibility to the bacteriocin cloacin DF13. Twelve of the 13 isolates were cloacin-resistant but became sensitive to this bacteriocin upon treatment with diphenylamine which caused a reduction in the amount of O-side chain lipopolysaccharide. 相似文献
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Yasushi KAWAI Kensuke ARAKAWA Ayako ITOH Boku SAITOH Yasuyuki ISHII Junko NISHIMURA Haruki KITAZAWA Takatoshi ITOH Tadao SAITO 《Animal Science Journal》2003,74(1):45-51
Gassericin A, a bacteriocin produced by Lactobacillus gasseri LA39, has a cyclic structure linking N‐ and C‐terminal amino acids. Gassericin A was expressed in Escherichia coli JM109 as a biotinylated fusion protein on the basis of the DNA sequence of mature bacteriocin. A positive clone accumulated the bacteriocin, with no activity, as a soluble fusion protein in the cytoplasm. After release of an N‐terminal tag with factor Xa protease, gassericin A was converted into an active peptide having N‐ and C‐termini. The total amount of purified bacteriocins (expressed and native) was 480 µg/L and 370 µg/L, respectively. However, the specific activity of expressed gassericin A was 15 AU/mg lower than that of native bacteriocin (2600 AU/mg). Although the actual Mr (molecular weight) of the expressed bacteriocin should be 5666, the peptide showed the same mobility (Mr 3800) in sodium dodecylsulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) as native cyclic gassericin A, suggesting that the expressed peptide retains compact folding of the molecule similar to that of native gassericin A. 相似文献
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为了初步研究前期试验筛选获得的枯草芽孢杆菌产细菌素的生物学活性,本试验采用杯碟扩散法绘制出硫酸黏杆菌素和杆菌肽锌两种抗生素的抑菌效价标准曲线,用抗生素效价当量来评价细菌素的活性,并在不同温度处理下测定其抗菌活性和热稳定性。结果表明,125 mg/mL细菌素溶液抑菌效价与26 mg/mL硫酸黏杆菌素或11.9 mg/mL杆菌肽锌溶液相当。此外,该细菌素在高温条件下(60~80 ℃)处理15 min仍能维持较高抑菌活性。综上所述,本试验在细菌素和抗生素的抑菌活力之间建立了更直观的联系,并证明了该细菌素具有较好的热稳定特性,为其产业化推广提供了理论支持和技术借鉴。 相似文献
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Effect of yeast with bacteriocin from rumen bacteria on laying performance,blood biochemistry,faecal microbiota and egg quality of laying hens
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H. T. Wang W. Y. Shih S. W. Chen S. Y. Wang 《Journal of animal physiology and animal nutrition》2015,99(6):1105-1115
The purpose of this study was to evaluate the effect of yeast with bacteriocin from Ruminococcus albus 7 (albusin B) on physiological state and production performance of laying hens. One hundred and twenty 26‐week‐old Single Comb White Leghorn (Hyline) laying hens were assigned into five groups including: (i) control group, (ii) yeast control (YC), (iii) 0.125% yeast with bacteriocin (0.125B), (iv) 0.25% yeast with bacteriocin (0.25B) and (v) 0.5% yeast with bacteriocin (0.5B). All supplements were added to the experimental diets of the hens from 26 to 46 weeks of age. Samples were collected every 4 weeks. Blood samples were collected from the wing vein for blood biochemical parameters assay, and faecal samples were collected by swab for the microbiota test. The egg production performance was recorded daily, and fresh eggs were collected for quality test. The blood biochemical assay results indicated that the addition of yeast with bacteriocin decreased the AST (aspartate aminotransferase) activity and it also affects the lactate concentration in laying hen blood. The result of egg quality indicated that yeast with bacteriocin supplementation had no effect on the mass of yolk and the strength of eggshell, but it had positive effect on the laying performance under hot environment. Low concentration bacteriocin (0.125B) supplementation could decrease total yolk cholesterol. The faecal microbiota result indicated that the supplementation of bacteriocin increased the lactobacilli counts. The yeast with bacteriocin supplementation significantly decreased the clostridia counts under hot environment condition, especially in hens receiving 0.25B. Combining the data from clinic chemistry, faecal microbiota, egg production and egg quality, the 0.25B supplementation may result in the best physiological parameter and egg production performance of laying hen. 相似文献
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WEI Xu-biao WU Ru-juan ZHENG Zhao-jun MA Guang LIAO Xiu-dong ZHANG Ri-jun 《中国畜牧兽医》2015,42(12):3268-3273
The standard curve of two antibiotics (colistin sulfate and bacitracin zinc) was carried out to assess antimicrobial activity of bacteriocin,which obtained from our earlier work,using cup-dish method.In addition,we also observed the effects of the reaction temperature on the antibacterial activity of the bacteriocin.Results showed that 125 mg/mL bacteriocin displayed similar antibacterial activity to 26 mg/mL colistin sulfate or 11.9 mg/mL bacitracin zinc.Furthermore,the bacteriocin remained good thermal stability under high temperature (nearly 60 to 80 ℃) in 15 minutes.Overall,this research built a direct relationship between this bacteriocin and antibiotics,and testified good stablility of this bacteriocin,providing theoretical support and technology reference to promote its large scale production. 相似文献
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WULIJIDELIGEN Takayuki ASAHINA Kazushi HARA Kensuke ARAKAWA Hiroyuki NAKANO Taku MIYAMOTO 《Animal Science Journal》2012,83(10):704-711
The purification and characterization of a bacteriocin produced by Leuconostoc mesenteroides strain 406 that was isolated from traditional Mongolian fermented mare's milk, airag, were carried out. Leuconostoc mesenteroides strain 406 was identified on the basis of its morphological and biochemical characteristics and carbohydrate fermentation profile and by API 50 CH kit and 16S ribosomal DNA analyses. The neutral‐pH cell‐free supernatant of this bacterium inhibited the growth of several lactic acid bacteria and food spoilage and pathogenic organisms, including Listeria monocytogenes and Clostridium botulinum. The bacteriocin was heat‐stable and not sensitive to acid and alkaline conditions, but was sensitive to several proteolytic enzymes such as pepsin, pronase E, proteinase K, trypsin, and α‐chymotrypsin, but not catalase. Optimum bacteriocin production (4000 activity units/mL) was achieved when the strain was cultured at 25°C for 24–36 h in Man Rogosa Sharpe medium. The bacteriocin was partially purified by ammonium sulfate precipitation (80% saturation), dialysis (cut‐off MW: 1000), and gel filtration chromatography. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis revealed that the bacteriocin had a molecular weight of approximately 3.3 kDa. To our knowledge, this is the first report of the isolation of a bacteriocin‐producing Leuconostoc strain from airag. An application to fermented milks would be desired. 相似文献
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乳酸菌产生的新型抗菌物质——苯乳酸的抑菌性质及作用机理研究 总被引:1,自引:0,他引:1
苯乳酸是微生物产生的一种新型天然抗菌物质,已成为乳酸菌抑菌能力的有效标志之一。与乳酸菌产生的细菌素(如乳链球菌素)相比,苯乳酸是小分子物质、抑菌谱宽、稳定性高。作为一种新型生物防腐剂,苯乳酸在乳品工业中具有广阔的应用前景。研究表明苯乳酸对多种食源性致病菌如致病性大肠杆菌、单增李斯特菌和金黄色葡萄球菌,腐败菌包括产毒素的丝状真菌如赭曲霉、疣孢青霉和桔青霉,有很强的抑菌作用。目前的研究表明苯乳酸的作用靶位之一是微生物的细胞壁,但阐明苯乳酸的作用机理需要采用相关技术进一步研究其他作用位点。本文对苯乳酸的抑菌活性、作用机理等研究进展进行综述,并展望了今后的研究方向。 相似文献
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JIANG Jing Ao-ri-ge-le WANG Chun-jie ZHANG Yan ZHAO Chen-he WU Hong-jun HAO Jian-gang 《中国畜牧兽医》2016,43(2):444-449
To study the physicochemical properties extracted from koumiss of Lactobacillus plantarum DSM20174 bacteriocin,we purified the Lactobacillus plantarum DSM20174 bacteriocins and got the bacteriocin crude extractions after ammonium sulfate precipitation and dialysis.After purification with Sephadex G-100 gel column chromatography,bacteriocin specific activity apparently increased,reaching 154.70 AU/mL,yield was 43.5%.We detected the effects of purified Lactobacillus plantarum DSM20174 bacteriocin on bacteriostatic action of wild bovine pathogenic E.coli O78 by Oxford cup method under 3 different treatments.The results showed that:①In five groups of temperature treatments,the bacteriostatic action decreased with the increase of temperature,bacteriostatic actions of all groups were significantly different (P<0.05).Even after treatment at 121 ℃ 30 min,antimicrobial diameter was 14.90 mm.② After Lactobacillus plantarum DSM20174 bacteriocin were treated with pH 2.0 to pH 12.0,the higher of pH,the smaller of antibacterial diameter.The inhibitory effect of groups were significantly different (P<0.05) except pH 9.0 and pH 10.0.③Lactobacillus plantarum DSM20174 bacteriocins were treated by trypsin,pepsin and papain,antibacterial diameter apparently changed,bacteriostatic action was significantly different (P<0.05) before and after treatment.The results suggested that Lactobacillus plantarum DSM20174 bacteriocins were better antibacterial substances,but not thermal stability substances.It had a relatively wide pH range,and the smaller of pH,the stronger of its antibacterial activity,the antibacterial activity had been enhanced at optimum growth pH.It was not protease stability substances. 相似文献