高效液相色谱法快速测定发酵液中的藤黄绿菌素

应用反相高效液相色谱,以φ=0.7甲醇为流动相,流速1.0mL/min,紫外检测波长308nm,建立了快速测定荧光假单胞菌M18发酵液中藤黄绿菌素(Pyoluteorin)的方法.实验结果表明,藤黄绿菌素在4.9min出峰,线性范围0.02~1g/L,线性范围良好(r=0.9997),最低检测浓度0.01g/L,回收率平均为97.7%.     

铜绿假单胞菌的LexA蛋白在大肠杆菌中的高效表达与纯化

目的:对铜绿假单胞菌(Pseudomonas aeruginosa,PA)的阻遏蛋白LexA进行基因克隆、重组表达及蛋白纯化.方法:采用PCR法从PAO1株基因组中扩增出1 086 bp的LexA基因,将此基因片段插入到表达载体pET32a( )上,并在大肠杆菌BL21(DE3)中表达.包涵体洗涤后用8 mol/L尿素溶解,以镍离子亲合柱层析作为第1步纯化,Superdex75凝胶过滤层析作为第2步精细纯化,反相高相液相色谱法(HPLC)测定蛋白的浓度.结果:LexA以包涵体形式表达,表达量为45%,经镍离子亲合柱层析纯化后LexA蛋白纯度达到85%以上,回收率大于80%,镍离子亲合柱层析和凝胶过滤层析两步纯化目的蛋白,经HPLC测定,最终目的蛋白的纯度为98.97%.结论:在pET32a( )表达系统中实现了PA的LexA蛋白的高效表达,两步纯化法获得高纯度的目的蛋白,为进一步鉴定LexA靶位点奠定了基础.     

马桑提取物的抑菌作用和抑菌机理的初步研究

马桑（Coriariasinica Maxim）为双子叶植物纲木兰亚纲马桑科（Coriariaceae）马桑属（Coriaria Linn）植物，多年生落叶有毒小乔木或灌木，野生．生长于山坡或山沟中．产于温带，广泛分布于河南、四川、贵州、云南等地．据研究报道，马桑全株有毒，其提取物对多种咀嚼式害虫具有明显的拒食和胃毒作用，马桑叶粉的30倍水浸液对马铃薯晚疫病孢子发芽有抑制作用；30倍水煮液对棉苗轮纹斑病菌和樱顶病菌袍子发芽也有抑制作用．     

海洋产灵菌红素细菌的基因分析与鉴定

报道了从大亚湾表面海水中分离到的１株海洋产灵菌红素细菌的分子鉴定结果．通过对该菌株１６ＳｒＲＮＡ基因的测定与分析,并与Ｇｅｎｂａｎｋ的数据进行比较,认为该菌属于假单胞菌属而不是色杆菌属．对于该菌株种的确定尚需进一步实验研究．     

溶微囊藻菌的分离与溶藻作用

从太湖梅梁湾水域放置的除藻中试反应器的人工介质上分离出1株溶藻细菌,并对该株菌溶解铜绿微囊藻和降解微囊藻毒素的效果与机制进行了研究.结果表明,结合形态学、生理与生化特性以及16S rRNA特异性引物扩增综合分析,初步鉴定该株细菌属于假单胞菌属;对源自太湖的微囊藻的最低溶藻细菌浓度为105个/mL;在太湖水、PBS缓冲液和BG11微囊藻培养基等反应体系中对微囊藻均有较强的溶解作用,24 h藻细胞溶解率分别为85.9%、67.9%和91.0%,完全溶藻时间为48 h.其溶藻方式可能为分泌某种胞外物质所致.该株菌对微囊藻毒素LR(MC-LR)也具有较强的降解作用.在MC-LR起始质量浓度为2.642 μg/L时,细菌对MC-LR作用18,36和72 h的降解率分别为14.2%、51.3%和100.0%.此菌株在太湖水中保持着较好的生物活性,表现出较强的溶藻与降解MC-LR作用.     

Isolation of indole-3-acetic acid methyl ester,a metabolite of indole-3-acetic acid fromPseudomonas amygdali

From the culture filtrates ofPseudomonas amygdali the methyl ester of indole-3-acetic acid (IAA), a product of indole-3-acetic acid metabolism which has the same auxin activity as the free acid, has been isolated. This is the first report of its occurrence as a microbial metabolite.     

Relevance of chlorine-substituent for the antifungal activity of syringomycin and syringotoxin,metabolites of the phytopathogenic bacteriumPseudomonas syringae pv.syringae

Structural analogues of syringomycin and syringotoxin were produced by fermentation, characterized by FAB-MS and amino acid analysis and compared to the parent compounds in the antibiosis test againstRhodotorula pilimanae. The C-terminal residue was shown to be important for the activity.     

Production of Medium Chain Length Polyhydroxyalkanoates by Pseudomonas mendocina 0806 from Related and Unrelated Carbon Sources

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假单胞菌GD—23原油发酵液乳化物质的提取和分析

GD-23菌株是降解烃类的细菌,经鉴定为假单胞菌属（Pseudomonas sp.)。该菌株在以原油为碳源的培养基中伴随菌体的生长产生一种对原油有乳化作用的物质,用弱酸阳离子交换树脂（H^ )可从原油发酵液中提取出来,理化分析表明,该乳化物质为一种水溶性的糖脂,其主要化学组分由C10脂肪酸和鼠李糖构成。     

Genetics of toxin production and resistance in phytopathogenic bacteria

Genes for phytotoxin production have been identified and cloned from several phytopathogenic pseudomonads. These genes comprise physically linked clusters that have been located both on the chromosome and on endogenous plasmids. Contained within these genetic regions are resistance genes specific to those toxins that have a bactericidal component to their activity. DNA sequences required for toxin production are often conserved among bacteria with divergent host specificities, suggesting the ability of toxin genes to be transferred between bacteria. Toxins are usually modulators of plant pathogenicity, their production causing a significant increase in disease severity. In one case, however, toxin production appears to be a major contributor to the basic pathogenicity of a plant pathogenic bacterium.