防腐剂对苏云金杆菌制剂活力毒力测定的影响

采用不同防腐剂剂处理苏云金杆菌制剂及毒力生物测定,结果表明,７＃（１００ｍｌ中含０．５ｍｌ１０％甲醛和１ｍｌ１５％尼泊金）防腐剂处理苏云金杆菌剂剂０－９６ｈ,抑制芽孢萌发和菌体活性的效果最佳,其次为２＃（１００ｍｌ中含１ｍｌ１５％尼泊金）,８＃（１００ｍｌ中含１ｍｌ１５％尼泊金和０．０５ｇ土霉素）;毒力生物测定７＃防腐剂最稳定,ＬＣ５０最小,灵敏度最高。     

关于我国苏芸金杆菌制剂毒力标准化问题的探讨

一、加强毒力标准化的研究已成为我国发展苏芸金杆菌制剂的当务之急。苏芸金杆菌(Bacillus thuringiensis)制剂毒力标准化是指以生物测定为基础,采用某种合适的单位来表示某种苏芸金杆菌制剂杀虫活性的大小,其目的是为了控制产品质量。自从     

微生物杀虫剂Bt53菌株的发酵培养基优化

运用正交试验L2 7(313 )设计法对鳞翅目昆虫高毒效的苏云金杆菌Bt5 3菌株进行培养基优化试验 ,在培养温度 30± 1℃ ,5 0ml/5 0 0ml三角瓶 ,摇床转速 180r/min条件下 ,苏云金杆菌 5 3菌株的发酵最佳培养基是 (% ) :碳源 0 5、氮源A 2 0、氮源B 0 10、氮源C 0 2 5、磷酸氢二钾 0 75、碳酸钙 0 15、硫酸镁 0 0 18及pH8 0。     

荧光增白剂对苏云金杆菌毒力的增效作用及其紫外防护功效的研究

以棉铃虫 (Ｈｅｌｉｏｔｈｉｓａｒｍｉｇｅｒａ)初孵幼虫为供试虫测试了三种二苯乙烯类荧光增白剂 (ｆｌｕ ｏｒｅｃｅｎｔｂｒｉｇｈｔｅｎｅｒｓ)ＴｉｎｏｐａｌＬＰＷ ,ＶＢＬ和ＪＤ 3对苏云金杆菌 (ＢａｃｉｌｌｕｓｔｈｕｒｉｎｇｉｅｎｓｅｓＢ .ｔ.)杀虫剂毒力的影响 ,并检测了荧光增白剂ＶＢＬ作为佐剂在Ｂ .ｔ.受紫外线照射时对Ｂ .ｔ.的光保护功效。结果表明 :添加 0 .1 2 5 % ,0 .2 5 % ,0 .5 %及 1 % (ｗ/ｗ)不同浓度荧光增白剂ＴｉｎｏｐａｌＬＰＷ的复混型苏云金杆菌制剂对初孵棉铃虫的ＬＣ5 0 值与单剂Ｂ .ｔ.的ＬＣ5 0 值…     

柳杉毛虫防治试验研究

用白僵菌、苏云金杆菌、2 4 .5 %全力、2 0 %氰戊菊酯等 4种杀虫剂的不同浓度对柳杉毛虫 (Dendrolimushoui L ajonquiere)进行室内毒力测定和林间防治试验 ,结果表明 ,野外防治柳杉毛虫以氰戊菊酯 6 0 0 0倍液 +苏云金杆菌 1.4× 10 9n/ ml+全力 80 0 0倍液 +白僵菌 1.2× 10 8n/ ml林间喷雾效果最佳 ,杀虫效果达 90 %以上。应用该复合剂大面积防治 2 0 hm2 ,效果达 80 %以上。     

从湖北神农架原始森林土壤中分离的高毒力苏云金芽孢杆菌

从神农架原始森林土壤中分离出苏云金芽孢杆菌 9株。经过生理生化和血清学鉴定 ,此 9株苏云金芽孢杆菌分属于H7、H6和H14。生物测定结果表明 :两株H7型菌株对棉铃虫幼虫有较高的毒力 ;另两株对致倦库蚊幼虫和白纹伊蚊幼虫有很强的毒杀作用 ,此两株属苏云金芽孢杆菌H14。     

球形芽孢杆菌Ts-1灭蚊毒蛋白的酶联免疫吸附测定

通过Sephadex G—200柱层析纯化得到球形芽孢杆菌Ts-1毒蛋白,其中主要是42Da和43kDa两种毒蛋白。用此毒蛋白免疫家兔获得抗血清。利用ELlSA双抗体夹心法比较测定了三种灭蚊球形芽孢杆菌(Bacillus sphaericus)高毒株和两种无毒株,证明ELlSA具有很强的特异性。ELISA测定球形芽孢杆菌Ta-1纯化毒蛋白,最低可检值为1．56 x 10-5mg／ml。球形芽孢杆菌Ts—1发酵液的最低可检度为1：16000倍稀释。ELISA测定12和24小时发酵培养的Ts—1样品处理液中毒蛋白的含量,分别为0．049mg／ml和0．22mg／ml,毒蛋白含量相差4.59倍。而相应的生物测定LC50。值分别为0．71 ppm和0．154 ppm,毒力相差4.61倍。 ELISA与生物测定方法结果吻合。     

苏云金芽孢杆菌发酵液中晶体蛋白定量测定方法的探讨

探索了一种苏云金芽孢杆菌发酵液中晶体蛋白化学定量测定的方法。发酵液经离心技术处理后,其晶体蛋白由还原剂、变性剂组成的裂解液溶解,再用紫外光谱吸收法或考马斯亮蓝染色法定量。该方法测得的晶体蛋白量与经生物测定得到的毒力之间有较好的相关性,在苏云金芽孢杆菌的研究和生产上有一定的实用价值。     

苏云金芽孢杆菌的紫外线诱变及筛选实验初步设计

苏云金芽孢杆菌(Bacillus thuringiensis)由于其自身特点,由其制成的杀虫剂已成为目前微生物防治害虫的重要手段之一。虽然苏云金芽孢杆菌制剂目前应用效果良好,但也存在一些隐患:长期使用该制剂会使害虫抗性增加,因此寻找新的高毒力菌株势在必行。本文以苏云金芽孢杆菌的库尔斯塔克亚种为研究对象,设计实验以紫外线诱变的方法获得毒力更强的菌种。     

苏云金芽孢杆菌杀虫晶体蛋白基cry3A在鳞翅目特异菌株中的表达及杀虫特性

将对鞘翅目昆虫有特异毒性的苏云金芽孢杆菌cry3A基因电转化到只对鳞翅目昆虫有毒性的苏云金芽孢杆菌野生型菌株YBT803-1中,获得转化了BMBY-001。SDS-PAGE分析及镜检结果表明,cry3A基因可在该菌株中高效表达,但出发菌株中原有的cry1Ab、cry1Ac及cry2的表达则受到不同程度的影响。生物测定结果显示,转化子BMBY-001对柳蓝叶甲(鞘翅目)具有较高毒力,LC50为0.413μL／mL(浸叶法),对小菜蛾(鳞翅目)的毒力比野生受体菌YBT803-1有所降低,LC50值为3.319μL／mL。     

Dysregulation of HER2/HER3 signaling axis in Epstein-Barr virus-infected breast carcinoma cells

The role of Epstein-Barr virus (EBV) in the pathogenesis of breast cancer has been of long-standing interest to the field. Breast epithelial cells can be infected by EBV through direct contact with EBV-bearing lymphoblastoid cells, and EBV infection has recently been shown to confer breast cancer cells an increased resistance to chemotherapeutic drugs. In this study, we established EBV-infected breast cancer MCF7 and BT474 cells and demonstrated that EBV infection promotes tumorigenic activity of breast cancer cells. Firstly, we showed that the EBV-infected MCF7-A and BT474-A cells exhibited increased anchorage-independent growth in soft agar. The increased colony formation capacity in soft agar was associated with increased expression and activation of HER2/HER3 signaling cascades, as evidenced by the findings that the treatment of HER2 antibody trastuzumab (Herceptin), phosphatidylinositol 3-kinase inhibitor, or MEK inhibitor completely abolished the tumorigenic capacity. In the EBV-infected breast cancer cells, the expression of EBV latency genes including EBNA1, EBER1, and BARF0 was detected. We next showed that BARF0 alone was sufficient to efficiently up-regulate HER2/HER3 expression and promoted tumorigenic activity in MCF7 and BT474 cells by the use of both overexpression and small interfering RNA knock-down. Collectively, we demonstrated that EBV-encoded BARF0 promotes the tumorigenic activity of breast cancer cells through activation of HER2/HER3 signaling cascades.     

Trypanosoma cruzi: immunoglobulin isotype profiles during the acute phase of canine experimental infection with metacyclic or blood trypomastigotes

A detailed investigation has been carried out about the serological profiles of groups of dogs experimentally infected with metacyclic (MT) or blood (BT) trypomastigotes of Berenice-78 Trypanosoma cruzi strain. Peripheral blood was collected from infected dogs and uninfected controls, weekly during 35 days following the acute phase of infection, and immunoglobulin profiles were determined by ELISA. Dogs infected with BT exhibited unaltered levels of IgG2, increases in IgM, IgE, IgA, IgG and IgG1. In contrast, dogs infected with MT presented unaltered levels of IgE and IgG1 and an increase in IgM, IgA, IgG and IgG2 levels. Compared with the MT group, animals infected with BT showed significant increases in IgM on days 7, 14 and 28, in IgA on days 7, 14 and 21, in IgE on days 7 and 14, in IgG on days 14 and 28, and in IgG1 on days 7, 14 and 21. Parasitemia levels of the infected animals were measured over the same time period. No correlations were found between the immunoglobulin profiles and the parasitemia levels. The results demonstrated that the inoculum source (BT or MT) influence the immunoglobulin isotype profile that may drive distinct outcome of acute canine Chagas disease.     

Improved 1, 2, 4-butanetriol production from an engineered <Emphasis Type="Italic">Escherichia coli</Emphasis> by co-expression of different chaperone proteins

1, 2, 4-Butanetriol (BT) is a high-value non-natural chemical and has important applications in polymers, medical production and military industry. In the constructed BT biosynthesis pathway from xylose in Escherichia coli, the xylose dehydrogenase (Xdh) and the benzoylformate decarboxylase (MdlC) are heterologous enzymes and the activity of MdlC is the key limiting factor for BT production. In this study, six chaperone protein systems were introduced into the engineered E. coli harboring the recombinant BT pathway. The chaperone GroES–GroEL was beneficial to Xdh activity but had a negative effect on MdlC activity and BT titer. The plasmid pTf16 containing the tig gene (trigger factor) was beneficial to Xdh and MdlC activities and improved the BT titer from 0.42 to 0.56 g/l from 20 g/l xylose. However, co-expression of trigger factor and GroES–GroEL simultaneously reduced the activity of MdlC and had no effect on the BT production. The plasmid pKJE7 harboring dnaK–dnaJ–grpE showed significant negative effects on these enzyme activities and cell growth, leading to completely restrained the BT production. Similarly, co-expression of DnaKJ–GrpPE and GroES–GroEL simultaneously reduced Xdh and MdlC activities and decreased the BT titer by 45.2 %. The BT production of the engineered E. coli harboring pTf16 was further improved to the highest level at 1.01 g/l under pH control (pH 7). This work showed the potential application of chaperone proteins in microorganism engineering to get high production of target compounds as an effective and valuable tool.     

四膜虫种间骨架蛋白组分的比较研究

以上海四膜虫S1和嗜热四膜虫BF株和BT株为材料,结合显微观察,采用生化抽提、SDS-PAGE电泳、扫描及数据统计,分析与测定了三个不同株四膜虫对数生长期皮层骨架蛋白组分与含量,结果显示嗜热四膜虫的BF与BT株差异较小,两者与上海四膜虫S1株差异则较大,S1株细胞中有92KD、72KD、66KD、32KD、27KD,而BF和BT株细胞中没有,估计这些蛋白的不同与种间亲缘关系及株系、培养条件等有着密不可分的联系.       

Isolation and characterization of long-chain alkane–degrading Acinetobacter sp. BT1A from oil-contaminated soil in Diyarbakır,in the Southeast of Turkey

A strain of long-chain alkane–degrading bacteria, BT1A, was isolated from oil-contaminated soil in Diyarbak?r, in the southeast of Turkey. Morphological, biochemical, and physiological characterization and 16S rRNA gene sequence analysis showed that the strain BT1A was a member of Acinetobacter genus, and it was found to be closely related to Acinetobacter baumannii. The strain BT1A was able to utilize crude petroleum as carbon and energy sources in order to grow. Among the aliphatic hydrocarbons, growth was observed only in the medium containing long-chain alkanes (tridecane, pentadecane, and hexadecane) and squalene. Hexadecane was the most preferred hydrocarbon among the long-chain alkanes. Gas chromatography–mass spectrometry (GC-MS) analysis showed that BT1A degraded 83% of n-alkanes of 1% crude oil in 7 days. The present study indicates that the isolated strain can well be used for biodegradation of hydrocarbons in oil-contaminated sites.     

中国苏云金杆菌工作的主要成就

<正> 苏云金杆菌是目前国际上生产量最大并成功地用于防治农、林、贮粮害虫和一些卫生害虫的微生物杀虫剂。我国早在50年代末、60年代初就已开始研制、应用工作,经历了30多年曲折的发展过程。为了更有效地控制害虫危害,保持生态平衡和减少环境污染,苏云金杆菌先后被国家列入“863”计划,“七五”、“八五”重点科技攻关项目和部、省级的重点课题,近年还列为国家“火炬计划”和“技改”计划及全国推广项目。近10多年来它的研究、生产、应用都获得较大的进展,主要有以下几个方面:     

一种新型花烛切花保鲜剂的效果

通过近两年的研究,我室研制出无毒、无腐蚀、无色、无污染的新型环保型高效花烛切花保鲜剂。经试验,该保鲜剂在较高和较低温度条件下保鲜效果稳定,与空白对照及含银保鲜剂相比,具有保鲜期长、切花质量好的效果。     

广东小菜蛾对苏芸金杆菌的抗性研究

广东省深圳,东莞、惠阳及博罗等供香港(以下简称供港)菜区小菜蛾对有机化学农药的抗性与广州内销菜区相近或稍高,对Bt杀虫剂的抗性则是供港菜区明显高于广州内销菜区。几种酶抑制剂TPP、SVl及Pb对Bt制剂无明显增效作用,可见小菜蛾对Bt制剂的抗性与酯酶和多功能氧化酶(MFO)的关系不大。用Bt制剂Dipel(大宝)连代选育小菜蛾敏感品系,选育18代,小菜蛾的抗性较选育前提高35倍。该抗性品系小菜蛾对个别菌株Bt及巴丹、杀虫双、速灭杀丁、万灵、敌敌畏等无交互抗性,而对昆虫生长调节抑制剂有轻微交互抗性。相反,用巴丹和杀虫双选育出的小菜蛾抗性品系对npel仍表现敏感。抗性品系小菜蛾在无触毒条件下饲养,抗性会自然减退,但不同类杀虫剂的抗性减退速率不尽相同。     

Role of estrogen receptors and antiestrogen binding sites in an early effect of antiestrogens, the inhibition of cholesterol biosynthesis

The effects of estradiol (E2), 4-hydroxy-tamoxifen (OH-Tam), and LY117018 on cholesterogenesis were investigated in two human breast cancer cell lines (MCF-7 and BT20), and in rat hepatoma (HTC) and fibroblastic (NRK-49F) cell lines. It was found that 10(-10) M E2 stimulated and 10(-8) M OH-Tam inhibited cholesterol synthesis in the estrogen-sensitive MCF-7 cell line. The OH-Tam effect occurred in less than 15 min whereas E2 only stimulated after 8 h. The inhibition of cholesterol synthesis was not reversed by E2. E2 was without effect in the HTC and estrogen-resistant BT20 cell lines whereas OH-Tam was as effective as in the MCF-7 cells. LY117018 had nearly as much effect on cholesterol synthesis as OH-Tam, in both MCF-7 and BT20 cells. Neither E2 nor OH-Tam had any effect on the NRK-49F cell line, even at micromolar concentrations. The three lines (MCF-7, BT20, HTC), whose cholesterol synthesis has been shown to be OH-Tam sensitive, appeared to contain high-affinity antiestrogen binding sites (AEBS); since the OH-Tam-resistant line (NRK) only contained low-affinity AEBS, there appears to be some relationship between OH-Tam sensitivity and high-affinity AEBS content. This suggests that the cholesterogenesis inhibition induced by antiestrogens is ER-independent and may involve AEBS. The cholesterogenesis stimulation induced by E2 occurred via a different pathway that appears to be related to the presence of ER in the cells.