一株水产地衣芽孢杆菌的鉴定及培养基优化

从水产养殖环境中分离、筛选得到一株菌CJ001,经菌落形态特征、生理生化特征及16S rDNA测序,鉴定其为地衣芽孢杆菌.地衣芽孢杆菌可有效降低养殖水体中的化学需氧量(COD),48 h内COD的降解率达86.8%,水温30℃时的降解率最高,达到85.7%.为优化培养基组成,选出由单因素试验确定的营养物质(红糖、玉米粉、豆粕、尿素)和NaH2PO4,进行5因素4水平的正交试验.结果表明,CJ001菌株的最佳堵养基配方为:红糖3%、玉米粉1%、豆粕3%、尿素0.25%、NaH2PO4 0.15%,其活菌数可达11.15×109 cfu·mL-1.     

芽孢杆菌芽孢内膜脂质的分离及图谱分析

以嗜热脂肪芽孢杆菌为研究对象,针对芽孢内膜脂质难以用传统的Bligh&Dyer方法直接提取的问题,重点分析芽孢脂质的分离过程,并构建了芽孢的脂质图谱.结果表明,碱性蛋白变性剂及溶菌酶能够剥离芽孢外衣、芽孢衣、外膜、肽聚糖等结构,使富含脂质的内膜结构裸露于芽孢表面,荧光染色试验进一步验证了芽孢外层结构剥离的有效性.内膜外露的芽孢用传统方法提取脂质后,用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术进行图谱分析.脂质组学研究表明,嗜热脂肪芽孢杆菌芽孢内膜脂质主要由磷脂酰甘油、磷脂酰乙醇胺及其衍生物、心磷脂组成.     

青霉素对枯草芽孢杆菌破壁效果研究

[目的]研究枯草芽孢杆菌生长期添加青霉素时的破壁效果.[方法]为使细菌释放出细胞内的有效活性物质,采用青霉素干扰微生物细胞壁形成的方法,研究不同的青霉素添加量对细胞的破壁效果.[结果]通过检测破壁前后菌体光密度变化值得出,在枯草芽孢杆菌的生长期,青霉素添加量对菌体光密度的变化有明显影响,青霉素添加量为25 mg/Kg,作用时间4 h,温度30℃时,光密度变化值(AOD)最高,达0.695,说明此时破壁效果最佳.[结论]青霉素对细胞具有一定的破壁效果,推测根据需要可以适量添加青霉素,使细菌释放出细胞内的物质.     

侧孢短芽孢杆菌碱性蛋白酶基因BLG4在枯草芽孢杆菌WB600中的高效表达

侧孢短芽孢杆菌G4菌株在侵染线虫的过程中可以分泌蛋白酶,降解线虫体壁,从而帮助细菌侵入宿主体内.在本文中,侧孢短芽孢杆菌的胞外蛋白酶BLG4基因经克隆后插入到改造后的枯草芽孢杆菌表达载体pWT22中,构建重组表达质粒pWT22-BLG4.构建成功的重组质粒通过化学转化法转入枯草芽孢杆菌蛋白酶缺失菌株WB6000中,转化子pWT22-BIG4/WB600在IPTG(1.0 mmol·L-1)的诱导下,发酵液上清中的蛋白酶活可达到620U·mL-1,高于出发菌株G4的BLG4酶活(240 U·mL-1).经SDS-PAGE分析,重组子pWT22-BLG4/WB600产生了一条分子质量约为30ku的条带,该条带的大小与侧孢短芽孢杆菌G4上清发酵液中BLG4条带的大小一致.而未经IPTG诱导的重组子pWT22-BLG4和经IPTG诱导的WB600则未出现该条带.结果证明侧孢短芽孢杆菌G4的碱性蛋白酶基因BLG4已在枯草芽孢杆菌WB600中获得了成功表达.重组蛋白酶具有与侧孢短芽孢杆菌G4产生的BLG4蛋白酶同样的酶学性质.同时,重组蛋白酶具有明显的杀线虫和体壁降解能力,表明其在线虫生物防治中将有广泛的应用前景.     

一株耐盐芽孢杆菌的分离与鉴定

从校园草坪土壤中分离得到一株能够在20%NaCl的高盐条件下生长的耐盐细菌,经过形态观察、生理特征分析及16SrDNA序列分析,鉴定为一株芽孢杆菌(Bacillus sp.),并在GenBank中完成该菌株16SrDNA序列的注册,登录号为EU167738.     

用巨大芽孢杆菌浸出矿石中的金

研究了用巨大芽孢杆菌(Bacillus megaterium)从金矿石中浸出金,考察了矿石粒度、矿石与细菌培养基用量配比、甘氨酸用量、体系pH对金浸出率的影响。结果表明:在矿石粒度为200～300目、矿石与培养基的配比为2 g/200 mL、甘氨酸用量12 g/L、体系pH=9.5、浸出时间24 d条件下,金浸出率达91.47%,浸出效果较好。     

多黏芽孢杆菌液态发酵条件的初步研究

[目的]优化多黏芽孢杆菌(Paenibacilus polymyxa)液态发酵的条件.[方法]在单因素试验基础上,栗用正交试验对多黏芽孢杆菌液态发酵培养条件进行优化.[结果]确定的最佳培养基配方和培养条件为:马铃薯250.0 g/L,白砂糖20.0g/L,玉米粉30.0 g/L,NaNO<,3>1.0 g/L,(NH<,4>)<.2>SO1.5 g/L,KH<,2>PO<,4>1.0g/L,pH6.5,装液量100 ml/250 ml(V/V),接种量5%(WV),培养温度37℃,摇床转速150 r/min,培养周期72 h.[结论]该研究可为工业化生产多黏芽孢杆菌提供参考.     

溶菌酶快速诱导蜡样芽孢杆菌L型的研究

[目的]研究溶菌酶诱导蜡样芽孢杆菌L型的技术条件.[方法]利用溶菌酶诱导蜡样芽孢杆菌L型,观察其形成、形态、生长及其对渗透压的敏感性等特性.[结果]在培养基中加入2 mg/ml的溶菌酶能够较好地诱导蜡样芽孢杆菌L型的产生,通过连续的培养获得了稳定的L型蜡样芽孢杆菌.L型蜡样芽孢杆菌呈球状,革兰氏染色阴性,对渗透压敏感.[结论]确定了蜡样芽孢杆菌溶菌酶法诱导L型的最佳浓度.     

胶质芽孢杆菌HJ07的UV与NTG诱变育种及其对铝土矿浸矿效果

以从河南铝土矿样筛选出的一株胶质芽孢杆菌HJ07为出发菌株,对其进行紫外(UV)与亚硝基胍(NTG)诱变育种及铝土矿浸矿脱硅研究.分别通过紫外线照射120 s与采用质量浓度为600 mg·L^-1的亚硝基胍处理,出发菌株HJ07的致死率分别达到89%与90%,正突变率分别达到16.5%与18.7%.从突变菌株中筛选所得的两株菌种UV-2与NTG-5的生长代谢活性与脱硅能力明显比出发菌株高.在铝土矿浸出体系中,UV-2与NTG-5达到生长稳定期的时间比HJ07分别缩短了48 h与24 h,且生长稳定期具有更大的细菌浓度.浸矿12 d后,UV-2与NTG-5菌株浸出液中SiO2的质量浓度分别比HJ07提高了约25.6%与12.5%,且达到浸出终点的时间分别缩短了3 d和2 d.UV-2与NTG-5菌株较出发菌株HJ07具有更强的产酸与产胞外聚合物的能力.被UV-2菌株作用后的铝土矿表面的溶蚀程度更加显著,矿物表面形成了明显的菌胶团.     

Conjugal transfer of transposon Tn916 from Enterococcus faecalis to Bacillus licheniformis

Transposon Tn916 was conjugally transferred from Enterococcus faecalis to Bacillus licheniformis bacterial strains ATCC 10716 and ATCC 9945A by filter and broth matings. The Tn916 transfer frequencies to B. licheniformis ranged from 10(-7) to 10(-5) selecting for tetracycline-resistant (Tcr) transconjugants depending on broth or filter mating. Movement of Tn916 was demonstrated when Tcr B. licheniformis transconjugants were mated with Bacillus subtilis strain W23. Tn916 insertion caused several auxotrophic and bacitracin deficient mutants. Southern blot analyses of HindIII chromosomal digests extracted from Tcr transconjugants showed that the transposon inserted at different sites in the B. licheniformis chromosome and the copy number of Tn916 varied. This approach should be useful for genetic studies of B. licheniformis.     

Fatty acids of vegetative cells and spores of Bacillus licheniformis

Lipids were extracted from vegetative cells and spores of Bacillus licheniformis. Vegetative cells were grown in nutrient broth and spores on nutrient agar. Total lipid approximated 2.89% of the dry weight of vegetative cells and 2.09% of the dry weight of spores. The fatty acids were prepared as methyl esters and analyzed by gas chromatography and mass spectrometry. There were six fatty acids in concentrations greater than 5% of the total lipid in both spores and vegetative cells, but only palmitic acid was common to both. Fatty acids from vegetative cells in quantities of 5% or more of the total lipid material were lauric, myristic, palmitic, palmitoleic, and linoleic acids. Fatty acids from spores in concentrations greater than 5% of the total lipid were isopentadecylic, palmitic, Carbon-17 iso, and three other long or branched chain fatty acids which were not identified. Spores contained more long and branched chain fatty acids with odd numbers of carbon atoms than did vegetative cells.     

Bioflocculation of Hematite and Goethite Using Bacillus licheniformis (Bio-flocculation of Hematite and Goethite)

Cells and metabolite of Bacillus licheniformis were applied in the bioflocculation of hematite and goethite. Effects of bioreagent type, pH, and solid concentration on the settling process were studied. The highest settling of hematite and goethite were obtained at pH 5 and 7, respectively. This observation was in agreement with the trend of bioflocculant adsorption. Also, among all the tested bioflocculants, bacterial cells showed the best flocculating ability. Moreover, mineral concentration and pH were determined as the most influential variables on hematite and goethite settling, respectively. Finally, all the tested bioreagents showed acceptable flocculating capabilities that were largely dependent on electrostatic forces.     

Characterization of a new lipopeptide surfactant produced by thermotolerant and halotolerant subsurface Bacillus licheniformis BAS50

Strain BAS50, isolated from a petroleum reservoir at a depth of 1,500 m and identified as Bacillus licheniformis, grew and produced a lipopeptide surfactant when cultured on a variety of substrates at salinities of up to 13% NaCl. Surfactant production occurred both aerobically and anaerobically and was optimal at 5% NaCl and temperatures between 35 and 45 degrees C. The biosurfactant, termed lichenysin A, was purified and chemically characterized. A tentative structure and composition for the surfactant are described. Lichenysin A is a mixture of lipopeptides, with the major components ranging in size from 1,006 to 1,034 Da. The lipid moiety contains a mixture of 14 linear and branched beta-hydroxy fatty acids ranging in size from C12 to C17. There are seven amino acids per molecule. The peptide moiety is composed of the following amino acids: glutamic acid as the N-terminal amino acid, asparagine, valine, leucine, and isoleucine as the C-terminal amino acid, at a ratio of 1.1:1.1:1.0:2.8:1.0, respectively. Purified lichenysin A decreases the surface tension of water from 72 mN/m to 28 mN/m and achieves the critical micelle concentration with as little as 12 mg/liter, characterizing the product as a powerful surface-active agent that compares favorably to others surfactants. The antibacterial activity of lichenysin A has been demonstrated.     

资产专用性对我国饭店业务外包的影响及实证研究

业务外包已经成为现代饭店管理经营的重要一面,而鲜有学者使用资产专用性理论来解释饭店业务外包行为.针对这种研究角度的缺失,在实证调查基础上探讨饭店业务外包的影响因素,结果显示影响我国饭店业务外包的主要因素是其资产专用性.     

Specificity of flavobacterial glycuronidases acting on disaccharides derived from glycosaminoglycans

An auxotroph enrichment procedure has been developed for Phycomyces blakesleeanus which has proven useful in obtaining both auxotrophs and drug-sensitive mutants. The technique is based on the differential heat sensitivity between ungerminated auxotrophic spores and germinated prototrophic spores. Germinated spores and mycelia die when left at temperatures higher than about 35 degrees C for 16 to 24 h but ungerminated spores survive this treatment and subsequently germinate if transferred to complete medium. With the dwarf colonial strain, replica plating permits the rapid characterization of these newly selected auxotrophs.     

Analysis of common antigen of flagella in Bacillus cereus and Bacillus thuringiensis

Flagellar antigen of Bacillus cereus H.1 was purified and tested for serodiagnostic antigen by ELISA. The antibody against the flagellar antigen of B. cereus H.1 reacted not only with the homologous specific antigen but also reacted with the flagellar antigens of 23 strains of B. cereus. This common flagellar antigen of B. cereus was found to be due to 61-kDa protein by SDS-PAGE and immunoblot assay. Monoclonal antibody H15A5 against common antigenic epitope of B. cereus also reacted with flagellar antigens of 21 strains of Bacillus thuringiensis by ELISA. This monoclonal antibody reacted with the 61-kDa protein of the flagella of B. cereus H.1 and H.2 and B. thuringiensis Kurstaki HD1, Alesti and Aizawai juroi by immunoblot analysis. These results indicated that the common antigenic epitope of the 61-kDa protein existed in the flagella both of B. cereus and B. thuringiensis.