共查询到20条相似文献，搜索用时 31 毫秒
1.
Bacillus subtilisis widely used for the productionof vitamins and other products including industrial en-zymes such as amylases, proteases and lipase. Butsyntheses of those products are repressed by the pres-ence of glucose, which is viewed as carbon catabolicrepression (CCR). InBacillus subtilis,CCR is main-ly mediated by the global regulator protein CcpAwhich was encoded byccpAgene[1]. It is therefore of crucial importance to relievingCCR ofBacillus subtilisfor industrial production. I… 相似文献
2.
用十二烷基硫酸钠消除枯草芽孢杆菌中的质粒 总被引：3，自引：0，他引：3
为获得宿主菌 ,研究了十二烷基硫酸钠 (SDS)对枯草芽孢杆菌中质粒的消除 .将过夜培养的枯草芽孢杆菌2 4/pMX45接种于含SDS( 0— 0 .0 0 8% )的LB培养基中 ,当SDS浓度 (w /v)大于或等于 0 .0 0 6 %时 ,菌体不能生长 .SDS的亚致死浓度为 0 .0 0 5 % ,其致死率达 99% .菌液稀释后涂LB平板 ,再随机挑选单菌落至抗性平板 ,检测由质粒编码的红霉素抗性是否丢失 .氯化铯 溴化乙锭梯度离心及质粒DNA的电泳图像证实了 2 4/pMX45的衍生菌株A7中的质粒已完全被消除 .A7延迟期较短 ,并且细胞浓度高于 2 4/pMX45 .用SDS处理 8h后 ,2 4/pMX45的遗传标记开始丢失 ,消除率持续增高至 2 2h ,随之消除质粒的菌体量保持恒定 .在未经SDS处理的对照实验中 ,相同条件下培养 2 4h及 48h后 ,没有发现质粒自然丢失的现象 ,因此SDS能消除枯草芽孢杆菌中的质粒 相似文献
3.
INTRODUCTION Soil-borne pathogens, including Pythium spp. and Fusarium spp., cause significant yield losses in horticulture and agriculture crops (Mao et al., 1997). Current practices for controlling plant diseases are based largely on disease resistant crops, cultivation management in fields and application of synthetic pesticides (Elizabeth and Emmert, 1999). Biological control using antagonistic microbes to reduce the use of chemical pesticides in a system of integrated plantdisease … 相似文献
4.
在接近人体生理pH条件下,采用紫外光谱法和液滴荧光法研究了核黄素和小牛胸腺DNA的相互作用.研究结果表明,随着DNA浓度增加,核黄素产生紫外光谱减色效应及荧光猝灭效应.进一步研究发现盐效应可使核黄素的荧光猝灭效应减小,由此推测核黄素与DNA之间可能存在嵌入作用和静电结合作用.通过计算和Scatchard作图求得该反应的结合常数与结合位点数. 相似文献
5.
报道采用热变性温度法(Tm)测定枯草芽孢杆菌和短小芽孢杆菌的DNA中G+C mol%分别为42.7mol%和40.26 mol%,与文献报道相一致,说明该法可为细菌分类学提供可靠的分子生物学数据.采用复性速率液相杂交法测定上述两菌DNA-DNA杂交度为9.66%,显示枯草芽孢杆菌与短小芽孢杆菌为同属中相互关系并不十分密切的两个种. 相似文献
6.
不同分子量壳聚糖的制备及其抑菌性能的研究 总被引：1，自引：0，他引：1
本实验在超声波条件下用过氧化氢降解壳聚糖制备低分子量壳聚糖,研究了过氧化氢用量、温度、时间、pH值等对壳聚糖溶液粘均分子量的影响,并对降解产物进行红外光谱分析。探讨了降解产物对大肠杆菌、白色念珠菌、枯草芽孢杆菌的抑菌性能。实验结果表明,超声波协同过氧化氢氧化降解壳聚糖的较适宜条件为:1%(w/v)的壳聚糖溶液,加入3%(v/v)的过氧化氢溶液,pH值约为5.0,数控超声清洗仪工作功率为80%,频率为40kHz,温度设定为(50.0±2.0)℃,随着降解时间不同可得到不同粘均分子量的壳聚糖。降解得到的产物对三种细菌均有抑制生长的效果,其中粘均分子量为5.0×104的壳聚糖的抑菌能力最强,且对大肠杆菌的抑制作用最强。 相似文献
7.
A process of biosorption of Cu2 , Zn2 and Cd2 on Bacillus subtilis was investigated. The experiments show that the process of biosorption is quite fast. The maximum adsorption was reached after 5 min and hardly changed with time. The experimental data was analyzed using four sorption kinetic models: the pseudo-first-order, the Ritchie second-order, the modified second-order and the Elovich equations, which helped to determine the best-fit equation for the sorption of metal ions onto biomass. The results show that both the Ritchie second-order and modified second-order equations can fit the experimental data. The Langmuir model is able to accurately describe adsorption of Cu2 and Zn2 on B. subtilis. The experimental data points of adsorption Cd2 and Zn2 on B. subtilis are described by Freundlich isotherms model. 相似文献
8.
采用比浊法和菌丝体湿重法测定生物量,测定了初烤烟叶蒸馏水浸出物对4种细菌和3种真菌生长的影响.结果表明,烟叶浸出物对细菌和真菌生长的影响不同.在剂量范围内,烟叶浸出物对铜绿假单孢菌（Pseudo-monas aeruginosa）,大肠杆菌（Escherichia coli）,枯草芽孢杆菌（Bacillus subtilis）和金黄色葡萄球菌（Staphylococcusaureus）没有抑制作用,对爪哇毛霉（Mucor jaranicas）,灰葡萄孢（Botrytis cinerea）和白色念珠菌（Canadida albi-cans）有抑制作用,抑制率分别为89.5%,74.8%和19.4%. 相似文献
9.
Studies on characteristics of nanostructure of N-TiO2 thin films and photo-bactericidal action 总被引：1，自引：0，他引：1
Pseudomonas aeruginosa strain （AS 1.50） and Bacillus subtilis strain （AS 1.439） from Ming lake were decomposed by photocatalytic nanostructure N-TiO2 thin films in a photo-reactor under UV irradiation. The different thickness nanostructure N-TiO2 thin films coated on mesh grid were prepared by sol-gel method and immobilized at 500 ℃ （films A） or 350 ℃ （films B） for 1 h in a muffle furnace. The results showed that N-TiO2 thin film B （8.18 nm thickness, 2.760 nm height and 25.15 nm diameter） has more uniform granular nanostructure and thinner flat texture than N-TiO2 thin film A （12.17 nm thickness, 3.578 nm height and 27.50 nm diameter）. The bactericidal action of N-TiO2 thin film A and film B for Pseudomonas aeruginosa strain （AS 1.50） and Bacillus subtilis varniger strain （AS1.439） were investigated in this work. More than 95% of photocatalytic bactericidal efficiency for Pseudomonas aeruginosa strain （AS 1.50） and 75% for Bacillus subtilis strain （AS 1.439） were achieved by using N-TiO2 thin films-B for 70-80 rain of irradiation during the photo-bactericidal experimental process. The results indicated that the photo-induced bactericidal efficiency of N-TiO2 thin films probably depended on the characteristics of the films. 相似文献
10.
以实验室保藏的一株具有溶解血栓能力的芽孢杆菌（LJQ—NK）为出发菌株,通过形态学分析和16SrRNA比对,对菌株进行鉴定,更进一步利用聚合酶链式反应（PCR）克隆纳豆激酶DNA片段⑤16SrRNA比对。结果表明LJQ-NK与已报道的纳豆激酶16SrRNA序列有99．9％以上的同源性,初步认定为一株纳豆芽孢杆菌。克隆获得1120bp的DNA片段,应用DNAMAN软件分析,与已报道的纳豆激酶编码基因（G129164926）存在两个碱基的差异,编码纳豆激酶开放阅读框区域序列完全相同。 相似文献
11.
本实验采用乳糖发酵短杆菌B_(27-12)作为出发菌株进行试验,首先,通过噬菌体敏感性试验,证明B_(27-12)对天津短杆菌T_(6-13)的五种噬菌体不敏感,从而证明B_(27-12)与T_(6-13)是不同噬菌体类型的谷氨酸生产菌。然后,将B_(27-12)用诱变效率高的原生质体诱变方法进行诱变选育,得到产酸较高的突变株,再进一步通过硫酸二酯(DES)和紫外线复合诱变法进行诱变,选育得到一株产酸较高的突变株D_(16)。 相似文献
12.
Yun-mei CHEN Hai-yang XU Yang WANG Jian-fa ZHANG Shi-ming WANG 《Journal of Zhejiang University. Science. B》2014,15(11):979-985
研究目的：提高胞外多糖索拉胶的产量。
创新要点：透明颤菌血红蛋白基因在质粒上表达,不加抗生素发酵生产索拉胶。
研究方法：将透明颤菌血红蛋白基因构建到广谱质粒pCM158上得到重组质粒pCM158-vgb,重组质粒转入土壤杆菌ZX09中,使透明颤菌血红蛋白在土壤杆菌ZX09中表达。
重要结论：在土壤杆菌ZX09中颤菌血红蛋白的表达解决了发酵过程中氧受限的问题,提高了宿主菌的呼吸速率、蔗糖酶活性和黏度,将发酵产物索拉胶的产量提高了30％。 相似文献
13.
Antibacterial and antifungal activities of different parts of Tribulus terrestris L. growing in Iraq
Antimicrobial activity of organic and aqueous extracts from fruits, leaves and roots of Tribulus terrestris L., an Iraqi medicinal plant used as urinary anti-infective in folk medicine, was examined against 11 species of pathogenic and non-pathogenic microorganisms: Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Corynebacterium diphtheriae, Escherichia coli,Proteus vulgaris, Serratia marcescens, Salmonella typhimurium, Klebsiella pneumoniae, Pseudomonas aeruginosa and Candida albicans using microdilution method in 96 multiwell microtiter plates. All the extracts from the different parts of the plant showed antimicrobial activity against most tested microorganisms. The most active extract against both Gram-negative and Gram-positive bacteria was ethanol extract from the fruits with a minimal inhibitory concentration (MIC) value of 0.15 mg/ml against B. subtilis,B. cereus, P. vulgaris and C. diphtheriae. In addition, the same extract from the same plant part demonstrated the strongest antifungal activity against C. albicans with an MIC value of 0.15 mg/ml. 相似文献
14.
Jing LI Qian YANG Li-hua ZHAO Shu-mei ZHANG Yu-xia WANG Xiao-yu ZHAO 《Journal of Zhejiang University. Science. B》2009,10(4)
An antifungal protein was isolated from a culture of Bacillus subtilis strain B29. The isolation procedure comprised ion exchange chromatography on diethylaminoethyl (DEAE)-52 cellulose and gel filtration chromatography on Bio-Gel P-100.The protein was absorbed on DEAE-cellulose and Bio-Gel P-100. The purified antifungal fraction was designated as B29I, with a molecular mass of 42.3 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), pl value 5.69 by isoelectric focusing (IEF)-PAGE, and 97.81% purity by high performance liquid chromatography (HPLC). B29I exhibited in-hibitory activity on mycelial growth in Fusarium oxysporum, Rhizoctonia solani, Fusarium moniliforme, and Sclerotinia scle-rotiorum. The 50% inhibitory concentrations (IC50) of its antifungal activity toward Fusarium oxysporum and Rhizoctonia solani were 45 and 112 μmol/L, respectively. B291 also demonstrated an inhibitory effect on conidial spore germination of Fusarium oxysporum and suppression of germ-tube elongation, and induced distortion, tumescence, and rupture of a portion of the germi-nated spores. 相似文献
15.
Keratinase production and keratin degradation by a mutant strain of Bacillus subtilis 总被引：2，自引：0，他引：2
A new feather-degrading bacterium was isolated from a local feather waste site and identified as Bacillus subtilis based on morphological, physiochemical, and phylogenetic characteristics. Screening for mutants with elevated keratinolytic activity using N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis resulted in a mutant strain KD-N2 producing keratinolytic activity about 2.5 times that of the wild-type strain. The mutant strain produced inducible keratinase in different substrates of feathers, hair, wool and silk under submerged cultivation. Scanning electron microscopy studies showed the degradation of feathers, hair and silk by the keratinase. The optimal conditions for keratinase production include initial pH of 7.5, inoculum size of 2% (v/v), age of inoculum of 16 h, and cultivation at 23 ℃. The maximum keratinolytic activity of KD-N2 was achieved after 30 h. Essential amino acids like threonine, valine, methionine as well as ammonia were produced when feathers were used as substrates. Strain KD-N2,therefore, shows great promise of finding potential applications in keratin hydrolysis and keratinase production. 相似文献
16.
17.
实验采用单因素试验优化纳豆菌固体发酵条件,通过蛋白凝块溶解时间法测定纳豆激酶活力,筛选出最佳培养条件。固态发酵通过扎孔、添加麦芽糖、蔗糖、葡萄糖和黄豆粉观察它们对纳豆菌产酶活力的影响。试验结果表明：固态发酵最佳条件为,浸泡10 h后,扎孔、添加4%麦芽糖、4%黄豆粉,121℃下蒸煮30分钟,接入纳豆菌2%,在37℃下培养24小时,4℃下后熟24小时。在此条件下培养,测得的纳豆激酶活力相当于尿激酶943.23 IU/g。与先前实验结果相比有了明显的提高：固态发酵由670.15 IU/g提高到943.23 IU/g。 相似文献
18.
设计了一种新型的烟气浸出物制备装置,测定烟气浸出物对4种细菌和3种真菌生长的影响.结果表明,在剂量范围内,烟气浸出物均能抑制细菌和真菌的生长.烟气浸出物对铜绿假单孢菌（Pseudom onas aeruginosa）,大肠埃希菌（Escherichia coli）,枯草芽孢杆菌（Bacillus subtilis）和金黄色葡萄球菌（Staphylococcus aureus）的抑制率分别为97.2%,86.2%,51.5%和81.7%.对爪哇毛霉（Mucor jaranicas）,灰葡萄孢（Botrytis cinerea）和白色念珠菌（Canadida albicans）的抑制率分别为95.5%,79.8%和98.9%.所设计的制备装置能有效获得烟气浸出物,可用于烟气浸出物生物学功能分析的标准化研究. 相似文献
19.
影响革兰氏染色结果的原因分析 总被引：1，自引：0，他引：1
为了提高革兰氏染色实验的教学效果,应用革兰氏染色法,探讨了菌种的菌龄、细菌涂片厚度、碘液媒染时间和乙醇脱色时间对革兰氏染色结果的影响。实验结果表明获得正确染色结果的条件为:首先将大肠杆菌、枯草芽胞杆菌和金色葡萄球菌在琼脂斜面培养基上分别培养22～25h、13～17h和18～24h;然后是制作细菌涂片时,取菌量要少于1/3环,涂菌稀薄、均匀;最后是染色。染色的第一步是用草酸铵结晶紫初染60s,再用碘液媒染60s,最后乙醇脱色时间是关键,应严格控制在30～45s为宜。只有控制好影响革兰氏染色结果的各个环节,才能得到正确的染色结果。 相似文献
20.
利用扫描电镜和交流阻抗法对以滴涂法制备的掺铝的硫化镉、壳聚糖修饰的玻碳电极进行纳米膜特性表征,并采用循环伏安法研究核黄素在其上的电化学行为.结果显示,在多种缓冲溶液中测试,发现在0.05 mol/L的邻苯二甲酸氢钾作为缓冲溶液时,电化学氧化还原峰形最好,峰电流较大.结果还表明,在修饰电极上的扩散系数D为5.08×10-4 cm2/s,反应速率常数k为5.36×10-7 mol/（L·s）.在实验优化选定的测试条件下,氧化峰电流与核黄素的浓度在5.00×10-6 ～4.50×10-5 mol/L范围内呈良好线性关系,检出限达2.55×10-6 mol/L,相对标准偏差（n=10）为4.25％,可用于核黄素含量的测定. 相似文献