溶源菌苏云金杆菌以色列变种

苏云金杆菌以色列变种(Bacillus thuringiensis vat.israelensis H14)经热处理灭活游离噬菌体后的培养物,经紫外线(UV)和丝裂霉素(Mitomycin)诱导,得到三株烈性噬菌体,並分离到一株自发突变的烈性噬菌体。这四株噬菌斑形态不同的噬菌体,对紫外线的敏感性和在20种血清型的32个菌株中的寄主范围各不相同,证明它们是四种不同类型的噬菌体。由于它们都是从苏云金杆菌以色列变种1897菌株中获得的,因此说明该菌株可能是多价溶源菌。     

苏云金芽孢杆菌BtR05菌株发酵培养基的优化

为提高苏云金芽胞杆菌BtR05菌株的发酵水平,本研究通过正交试验并将优选出的培养基组合进行综合优选,最终筛选出的培养基为:玉米粉2%,豆粕粉3%,蔗糖1%,硫酸铵0.1%,三水磷酸氢二钾0.3%,磷酸二氢钾0.2%,七水硫酸镁0.04%,酵母提取物0.3%和碳酸钙0.3%.该培养基配方在接种量为3%,200 r/min.30℃摇瓶振荡培养至44 h时,芽孢率达90%,活菌数达37.33×108cfu/ml.     

苏云金芽孢杆菌4.0718菌株的杀虫晶体蛋白基因分析

根据苏云金杆菌(Bacillus thuringiensis)cry1、cry2和cry3型基因的保守区分别设计了3对通用引物Un1(d)/Un1?、Un2(d)/Un2?和Un3(d)/Un3?,以Bt4.0718菌株质粒DNA为模板进行PCR扩增,通过扩增产物片段的分子量大小来确定该菌株所含有的杀虫晶体蛋白基因类型。随后根据上述3类cry基因的高变区设计特异引物再次进行PCR鉴定。结果表明:Bt4.0718菌株含有cry1Aa、cry1Ab、cry1Ac、cry1Cb、cry2Ac和新基因cry4.5等6种基因类型。这一结果为利用该菌株构建高效广谱杀虫工程菌提供了客观依据。     

苏云金芽孢杆菌两株溶原性噬菌体的生物学特性

研究苏云金芽孢杆菌(Bacillus thuringiensis)的溶原性及其噬菌体的生物学特性,从生产菌株MZ1中分离了两株溶原性噬菌体。MZ1经诱导后产生直径约为3mm和1mm的噬斑,分离获得属长尾噬菌体科的噬菌体MZTP01和MZTP02两株;分别对6株和7株不同亚种的Bt菌株具有侵染力;免疫血清与相应噬菌体的中和反应K值分别为45和326,且两者无相关抗原性。MZTP01抵抗酸、碱、紫外线和热的能力比MZTP02强,但抵抗有机溶剂的程度比MZTP02弱。MZTP01的潜伏期为80min,裂解量为55;MZTP02的潜伏期为40min,裂解量为175。核酸结构分析均表明为线性dsDNA分子。两基因组DNA的凝胶电泳表明分子量均在9.4~23kb之间,并被HindⅢ酶切分别产生8条和9条清晰条带。该菌株被证明为二元溶原菌,可能是造成生产损失的主要原因;为防治溶原性噬菌体提供了生物学信息。     

苏云金芽孢杆菌几丁质酶的研究进展

苏云金芽孢杆菌制剂作为无公害农药已经得到社会的认可,如果再开发其几丁质酶抑制真菌和杀虫增效功能,不仅可充分利用这一农业微生物菌种资源,也将给予传统生物农药以新的生命力。综述了苏云金芽孢杆菌几丁质酶方面研究的国内外最新进展。     

杀鞘翅目苏云金芽孢杆菌新菌株及其杀虫剂的研究

从中国土壤中分离出2株杀鞘翅目昆虫的苏云金芽孢杆菌(Bacillus thuringiensis) YM03及SHQ11-10。YM03的血清型为H8a8b,SHQ1110的H血清型未知。二菌株皆产近菱形的薄扁伴孢晶体,分别含68～70kD和65kD的晶体蛋白质。毒力生物测定证明对柳蓝叶甲(Plagiodera versicolora)及马铃薯甲虫(Leptinotarsa decemlineata)有高毒效。发酵性能良好。YM03粉剂田间防治马铃薯甲虫有高效。稀释400倍喷雾,防治效果达94.6%。     

苏云金芽孢杆菌杀蚊菌株研究进展

苏云金芽孢杆菌作为生物杀虫剂已有近百年历史,其杀虫谱包括从鳞翅目、鞘翅目、膜翅目、双翅目到线虫甚至是癌症细胞,对农林业生产以及医学领域研究具有非常重要的作用.全球每年死于蚊媒疾病的数目惊人.本综述首先介绍了首个被发现对双翅目幼虫具有杀蚊活性的苏云金芽孢杆菌以色列亚种,详细叙述了该菌株的杀虫功能、菌株特点以及含有的多种杀...     

苏云金芽孢杆菌不同亚种菌株制剂毒力效价的研究

采用苏云金芽孢杆菌制剂美国标准品:Bacillus thuringiensis subsp. Kurstaki HD-1-S-1980(H_(3a3b))对不同亚种制剂:Bacillus thuringiensis subsp. Dendrolimus U菌株(H_(4a4b))和Bacillus thuringiensis subsp. Galleriae C88菌株(H_5a5b))进行了毒力效价的研究。以U菌株制备的标样与美国标准品对不同试虫进行了比较。生物测定的结果表明,U菌株标样的效价分别为18666.6IU/mg(试虫为马尾松毛虫Dendrolimus punctatus 2龄幼虫)、22956.5IU/mg(试虫为小菜蛾Plutella xylostella 2龄幼虫),均高于美国标样16000IU/mg的水平。其敏感度为小菜蛾大于马尾松毛虫。以U菌株和C88菌株生产的中试产品用美国标准品进行毒力测定,试虫为马尾松毛虫,其结果表明,U菌株产品毒力效价为36444.4IU/mg;C88菌株产品为28521.7IU/mg,两者均明显高于美国标准品。试验结果还表明,采用美国标准品及马尾松毛虫和小菜蛾为…     

苏云金芽孢杆菌Cyt蛋白研究进展

苏云金芽孢杆菌 (Ｂａｃｉｌｌｕｓｔｈｕｒｉｎｇｉｅｎｓｉｓ,简称Ｂｔ)是目前世界上应用最广泛、最成功的微生物杀虫剂 ,也是公认的无公害生物农药。苏云金芽孢杆菌最主要的杀虫活性物质是杀虫晶体蛋白 (ＩｎｓｅｃｔｉｃｉｄａｌＣｒｙｓ ｔａｌＰｒｏｔｅｉｎｓ,ＩＣＰｓ) ,包括晶体蛋白 (Ｃｒｙ)和Ｃｙｔ蛋白 (Ｃｙｔ)两大类。这两类蛋白在氨基酸序列及其基因同源性上相距甚远 ,但它们均能在靶标害虫中肠内被激活成毒素 ,并在昆虫中肠细胞膜上形成孔道 ,进而引起中肠细胞胶样渗透裂解 (ｃｏｌｌｏｉｄ ｏｓｍｏｔｉｃｌｙｓｉｓ) ,最…     

苏云金芽孢杆菌的筛选和初步鉴定

采集四川温江昆虫孳生地的土壤样本94份,利用醋酸钠-抗生素法分离、筛选,共获得苏云金芽孢杆菌9株。镜检可观察到大菱形、小菱形、方形、圆形等四种主要形态的伴胞晶体;采用cryⅠ、cryⅡ、cryⅢ、cryⅤ基因的通用对9株Bt分离菌进行的PCR检测结果表明：9株菌全部含cryⅠ和cryⅤ基因,2株菌含cryⅡ基因,5株菌含cryⅢ基因,而且各菌株均包含2—3个基因型。利用这些菌株对菜青虫进行了室内和室外生物毒力测定,达到了较好的杀虫效果。     

Mechanism of action of Bacillus thuringiensis var israelensis insecticidal δ-endotoxin

Bacillus thuringiensis var israelensisδ-endotoxin protein active against mosquitoes was inactivated by prior incubation with lipids extracted from Aedes albopictus cells. Experiments with lipid dispersions and multilamellar liposomes showed that the toxin binds to phosphatidyl choline, sphingomyelin and phosphatidyl ethanolamine provided these lipids contain unsaturated fatty acids. Phosphatidyl serine binds toxin less efficiently and phosphatidyl inositol, cardiolipin, cerebroside and cholesterol show no affinity for the toxin. The results suggest an insecticidal mechanism in which interaction of toxin with specific plasma membrane lipids causes a detergent-like rearrangement of the lipids, leading to disruption of membrane integrity and eventual cytolysis.     

Identity of hemolysins produced by Bacillus thuringiensis and Bacillus cereus

A hemolysin (Bt-hemolysin) produced by Bacillus thuringiensis var. kurstaki HD-1 producing crystalline toxin(s) was purified by successive treatments of ammonium sulfate (45-65%) and column chromatography using DEAE-cellulose, Sephadex G-75 and KB-002 (a hydroxyapatite column for fast protein liquid chromatography). A hemolysin (Bc-hemolysin) produced by B. cereus HG-6A was also purified by the same procedure. The purified Bt-hemolysin and Bc-hemolysin, both of which are thiol-activated hemolysins, were biologically, physicochemically and immunologically identical. These findings provide further evidence of the similarity of B. thuringiensis, which is being used as a biological insecticide, to B. cereus, a toxigenic organism of food poisoning.     

Phenotypic and genotypic comparisons of 23 strains from the Bacillus cereus complex for a selection of known and putative B. thuringiensis virulence factors

Sixteen Bacillus thuringiensis, four Bacillus cereus and three Bacillus anthracis isolates were screened for a selection of known and putative B. thuringiensis virulence factors. PCR primers were designed to detect genes for phosphatidylcholine specific phospholipase C, phosphatidylinositol specific phospholipase C, immune inhibitor A, vegetative insecticidal protein 3A, a protein proposed to be involved in capsule synthesis, a newly identified Ser/Thr kinase homologue and enterotoxin entS. Motility, the presence of flagella, haemolysis, chitinase and lecithinase production were also evaluated. The widely varying profiles of the 23 strains from the complex provide a pool of different genotypes that can help to identify factors involved in pathogenicity.     

Diarrhoeal enterotoxin production by strains of Bacillus thuringiensis isolated from commercial Bacillus thuringiensis-based insecticides

Abstract Strains of Bacillus cereus and B. thuringiensis were tested by the Tecra VIA kit for the ability to produce a diarrhoeal enterotoxin. The strains of B. thuringiensis were isolated from commercial B. thuringiensis -based insecticides (Bactimos^TM, DiPel^TM, Florbac^TM FC, Foray^TM 48B, Novodor^TM FC, Turex^TM, VecTobac^TM, XenTari^TM). The production of diarrhoeal enterotoxin varied by a factor of more than 100 among the different strains tested. B. cereus (F4433/73) produced the highest amount of enterotoxin and the B. thuringiensis strain isolated from DiPel^TM the lowest. The products were tested for their content of diarrhoeal enterotoxin and all products, except MVP^TM which does not contain viable B. thuringiensis spores, contained diarrhoeal enterotoxins. The results indicates an potential risk for gastroenteritis outbreak caused by B. thuringiensis .     

芽孢杆菌原生质体的形成,再生及种间融合的研究

原生质体融合技术不仅能使遗传基因高频率重组,而且可以集双亲优良遗传性状为一体.自Schaeffer等人成功地进行了微生物原生质体融合以来,这项技术便广为人们所接受.枯草芽孢杆菌分泌的抗菌蛋白能抑制多种植物病原菌的生长,苏云金芽孢杆菌生成的伴孢晶体蛋白可毒杀植物害虫.利用原生质体融合技术将这两种芽孢杆菌抑菌杀虫的遗传特性融为一体,选育出防治植物病虫害的新一代生防菌株成为可能,有关这方面的研究国内外尚未见报道.本文报道了抗菌蛋白产生菌TG26-10和晶体蛋白产生菌AS1.904-17原生质体的形成,再生及种间融合的影响因素,为进一步筛选目的融合子提供基础.     

转Bt基因作物种植对土壤养分含量的影响

转Bt基因棉花和水稻的盆栽种植试验结果表明,与非转Bt基因原始对照相比,转Bt基因水稻短期种植30 d和转Bt基因棉花种植一个生长季后土壤中全碳和全氮以及碱解氮、速效磷、有效硫含量与对照均无显著差异,表明转Bt基因作物的种植短期内对土壤主要营养元素循环和平衡的扰动是微小的.     

Nickel Bioremediation Potential of Bacillus thuringiensis KUNi1 and Some Environmental Factors in Nickel Removal

The present study endeavors to isolate a nickel (Ni)-resistant bacterial strain from an industrial waste–contaminated soil sample and to characterize the strain with a view to identify it and to assess its ability to remove Ni from the medium or detoxify it. The final objective is to use the strain as an agent to bioremediate Ni contamination. As an outcome, a Ni-resistant bacterial strain (KUNi1) had been isolated from such a soil that could tolerate a maximum of 7.5 and 10 mM Ni concentrations, depending on the type of medium used. The strain also showed multimetal resistance. It was found to be resistant to zinc (Zn), copper (Cu), cobalt (Co), and cadmium (Cd). However, the degree of resistance to the individual metal was variable, as determined by assessing the minimum inhibitory concentration (MIC) of each metal against the strain. The order of resistance was Ni > Zn = Cu = Co > Cd. The strain removed a significant percentage (82%) of Ni from the medium during in vitro culture, whereas dead cell mass had an insignificant role in Ni removal. The quantum of Ni removal by the strain was interfered with when the other metals (Zn, Cu, Co, and Cd) were present either singly with Ni or in combination with other metals. However, the degree of interference varied with individual metal. The factors that influenced the quantum of Ni removal were ambient pH, initial cell density, and presence of other toxic metals. The strain was identified as Bacillus thuringiensis on the basis of its biochemical characteristics and 16s rDNA sequence analysis.