豆鼓溶栓酶产生菌的筛选及其酶学性质的初步研究

利用纤维蛋白平板筛选，纤溶活性测定，SDS－PAGE分析和体外溶栓实验等相结合的方法，成功地从豆豉中筛选到一株纤溶活性高达520U／mL和具有良好体外溶栓效果的细菌菌体（编号为DC－4），经鉴定为解淀粉芽孢杆菌（Bacillus amyloliquefaciens)。SDS－PAGE和纤维蛋白自显影表明该酶的分子量为28kD，其最适反应温度和pH值分别为42℃和8．0，在pH6-10较稳定。PMSF和盐酸苯甲醚能抑制纤溶活性，而EDTA和EGTA不能抑制，表明该酶是一种丝氨酸蛋白酶。它溶解纤维蛋白的方式是直接溶解纤维蛋白，而不激活纤溶酶原，并且不水解血细胞。     

脂肪酶产生菌的筛选及酶学性质

采取含油脂泥土,通过富集培养,平板筛选,得到多种菌株,酶活测定表明一株地酶属菌株酶活较高,对其酶学性质进行了研究。     

低温脂肪酶产生菌的筛选、鉴定及其部分酶学性质

从南极乔治王岛冻土来源的76株低温细菌中筛选到13株低温脂肪酶产生菌，对其中的BTsl0022菌株进行鉴定。通过生理生化特征、16s rDNA基因序列的同源性和系统发育分析发现，菌株RTsl0022属于假单胞菌属(Pseudomonas)，但与已定名的假单胞菌有一定的差异，与未定名的Pseudomonas sp．PsB的亲缘关系最接近，故将其暂定名为Pseudomonas sp．BTsl0022。对该菌脂肪酶的酶学性质初步研究表明，酶的最适作用温度为24℃，对热敏感，60℃处理30min仅残留25％酶活性，酶的适宜作用pH范围在7．0～9．0，最适pH为8．0。     

高活性几丁质酶产生菌的筛选及鉴定

从四川、陕西、浙江等地食用菌栽培的土壤样品中,筛选到一株性能优良、产几丁质酶活力较强的菌株BLC08609,并结合菌落形态、生理生化指标和16S rDNA序列分析对其进行鉴定.结果显示,菌株BLC08609能以食用菌细胞壁(以几丁质为主)为唯一碳源生长,在菌株BLC08609个体形态和生理生化特性鉴定的基础上,通过16S rDNA测序鉴定,确定BLC08609为地衣芽孢杆菌(Bacillus licheniformis).     

产蛋白酶菌株的筛选鉴定及产酶优化

为筛选出高产蛋白酶的菌株,通过干酪素培养基筛选到一株高产蛋白酶的菌株BJ-4,经鉴定该菌株为解淀粉芽孢杆菌（Bacillus amyloliquefaciens）。对菌株的产酶条件进行单因素及响应面优化,确定最佳产酶条件为：葡萄糖0.5%、牛肉膏1.5%、培养温度37.61℃、培养初始pH值6.84、接种量1.36%,优化后酶活力同比增长了71.01%。菌株BJ-4在工业中具有一定的应用前景。     

米曲霉淀粉酶酶学性质的研究

对本实验室筛选的米曲霉淀粉酶的酶学性质进行了研究。该淀粉酶的最适温度为60℃,T为65．2℃,其热稳定性较差：最适pH为pH5．0,在pH4．0-8．0范围内稳定性较好。K＋对淀粉酶活性具有显著促进作用,而Ag2＋、Ph2＋、Fe3＋和Cu2＋对其活性具有强烈的抑制作用。     

产蛋白酶菌株的筛选及其在固态发酵豆粕中的应用

目的:筛选高产蛋白酶菌株,探究微生物发酵对豆粕抗原蛋白的影响,以期提高豆粕在水产饲料中的使用价值。方法:从土壤样品中筛选出1株蛋白酶酶活为1 390.6±12.5 U/mL的菌株LX-6,经生理生化特性和16S rDNA分子鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。通过B.amyloliquefaciens LX-6不同时间发酵豆粕,分析SDS-PAGE中大分子抗原蛋白降解情况、发酵样品总蛋白以及水溶性蛋白含量。结果:在37℃、物料含50%水的条件下,发酵24 h豆粕中大分子抗原蛋白全部降解,48 h时水溶性蛋白含量达到最高44.45%。结论:B.amyloliquefaciens LX-6发酵后有效提高了豆粕的蛋白含量,此发酵豆粕有望今后开发成水产饲料。     

黑曲霉内切聚半乳糖醛酸酶A基因在大肠杆菌中的表达及产物酶学性质研究

采用Trizol法提取黑曲霉(Aspergillus niger JL-15)的总RNA,RT-PCR扩增到黑曲霉内切聚半乳糖醛酸酶A基因(pgaA),pgaA全长1113bp,编码370个氨基酸残基.pgaA经EcoRI和NotI双酶切,定向插入到表达载体pET-32a(+)中,并转化Escherichia coli Rosetta-gami B(DE3),重组子经IPTG诱导,其表达产物(rePGA)果胶酶活性最高为637.0U/mg.酶学性质研究表明,rePGA的最适温度为60℃,热稳定性较差,最适pH为pH 5.0;Ca2+对其活性具有显著促进作用,而Fe3+和Mg2+对其活性具有显著抑制作用;SDS-PGAE结果表明,rePGA的相对分子质量约为40 500Da;rePGA的米氏常数(Km)和最大反应速度(Vmax)分别为4.05mg/mL和39.37μmol/(mL.min),rePGA能快速降低果胶溶液的粘度,符合其内切作用模式特点.     

优化米曲霉固体发酵产果胶酶及产物酶学性质

以麸皮为基质,橘皮粉添加量、氮源、培养基初始含水量和发酵时间为因子,采用响应面法的中心组合设计,对影响米曲霉(Aspergillus oryzaeJL14)固体发酵产果胶酶的条件进行了优化.结果表明,橘皮粉、硫酸铵的最适添加量分别为13.2%和2.3%,初始含水量为63.5%,发酵时间为77.0 h,米曲霉果胶酶产量最大预测值达316.4 U/g发酵产物,实验验证值为310.7 U/g发酵产物,是基础培养基酶产量的3.3倍.该米曲霉果胶酶(PG)的最适温度为50℃,Tm为55.9℃,其热稳定性较差;最适pH为4.0,属于嗜酸性果胶酶,在pH 5.0~8.0范围内稳定性较好,处理1 h后残余酶活均在80%以上.PG的Km和Vmax分别为7.06 mg/mL和62.5μmol-1.min.mL-1.PG能快速降低果胶溶液的黏度.该研究为提高橘皮利用率和酶法生产高品质果胶低聚糖奠定基础.     

低温纤维素酶产生菌的筛选、鉴定、生长特性及酶学性质

从北极楚科奇海分离出一株产纤维素酶的耐冷假交替单胞菌BSw20308。研究表明：该菌最适生长温度10℃,35℃不生长;在pH7．0～8．0、含2．0％～3．0％NaCl的培养基条件下最适宜菌株生长与产酶;可溶性淀粉、酵母浸出液是有利于菌株生长及产酶的碳源、氮源物质;蔗糖、可溶性淀粉、麦芽糖及麸皮对CMCase的合成具有明显诱导作用;CMC、麸皮、可溶性淀粉及麦芽糖对滤纸酶的合成有一定诱导作用,单糖与部分双糖(蔗糖、纤维二糖及乳糖)则起阻遏作用;在指数生长后期至稳定早期,大量产CMCase;发酵液含CMCase、滤纸酶及葡萄糖苷酶活性,以CMCase活力最高;胞外CMCase活力占总CMCase活力的74．1％左右;酶最适作用温度35℃,5℃时酶活保留50％左右;酶对热敏感,35℃半衰期为3h,25℃下酶活稳定;酶最适pH8．0。     

Isolation and Characterization of Ciprofloxacin-HCL Crystals

Three crystalline and one amorphous form of Ciprofloxacin-HCL were prepared and characterized by various instrumental techniques. The hygroscopicity, stability, and solubility of all the forms were also determined. Results indicated that all three crystalline and one amorphous form had distinctly different properties. Form I and II were identified as hydrates and Form III as dimethyl formamide (DMF) solvate. Stability determination of various forms under different conditions indicated that Form II was most stable against temperature and Form I against humidity. Among crystal forms, Form I was found to possess maximum aqueous solubility and was expected to exhibit maximum bioavailability.     

Isolation and Spectroscopic Characterization of Eu@C72

A new Eu-endohedral fullerene cage, namely, Eu@C₇₂, was synthesized, separated, and a single isomer, Eu@C₇₂-I, has been isolated by multi-step HPLC for the first time and characterized by LDI-TOF mass spectrometry, UV-Vis and EPR spectroscopy. Additionally, a second isomer, Eu@C₇₂-II, has been separated by HPLC and identified by LDI-TOF mass spectrometry.     

一株草苷膦极端抗性菌株的分离和分子鉴定

从极端污染的土壤中 ,分离到一株对草苷膦有极端抗性的细菌菌株HTG7。它能够在以草苷膦为选择压力的限制性培养基上生长 ,其最高耐受能力为 5 0 0mmol/L。采用PCR扩增获得该菌 16SrDNA片段。核苷酸序列分析表明 ,该菌的 16SrDNA核苷酸序列与盐单胞菌属同源性最高 ,在 95 %～ 98%之间。在细菌系统分类学上 ,HTG7归属盐单胞菌属Variabil。     

抗氧化型枯草杆菌碱性蛋白酶高产工程菌的构建及其酶学特性

通过基因重组,定点突变,基因整合和诱变等手段构建了一个抗氧化型枯草杆菌碱性蛋白酶高产工程菌株B135,试管及三角瓶发酵结果显示,酶产量是10048U/ml,是2709碱性蛋白酶产量的55％,抗氧化型碱性蛋白酶浓度是5．9mg/ml,该酶与1mol/L过氧化氢作用15min后,酶活保存90％以上,而709则保存12％,说明B135碱性蛋白酶是抗氧化的。     

硫系高效脱臭菌的分离及其特性研究

从三个不同地点采集的混合样品中，分离到16株能氧化无机硫化物的菌株，优化筛选出菌株Hm-6，其形态，生理生化反应特征鉴定为假单菌（Pseudomonas sp.)。研究了菌株Hm-6氧化H2S的影响因素和代谢过程。确定Hm-6菌株的生长最适温度为30℃，pH值为7；将其投加到泥炭生物过滤塔中，室温即对低浓度H2S有较高的去除效果，且没有延迟期，代谢产物是类硫物质，而不是通常的硫酸根。     

PBS/MMT纳米复合材料的制备及表征

以聚丁二酸丁二醇酯(PBS)为基材,经十六烷基三甲基溴化铵(CTAB)改性过的纳米蒙脱土为填料,采用熔融共混法,制备了PBS/MMT纳米复合材料,并研究了该复合材料的热稳定性能、力学性能和流变性能等。结果表明:当改性nano-MMT的添加质量分数为5%时,复合材料的熔点约提高了2.55℃,热初始分解温度提高了33℃;当其添加质量分数为3%时,复合材料的拉伸强度提高了9%,断裂伸长率提高了3%,冲击强度提高了23%;复合材料的流变性能比纯PBS的流变性能有一定程度的提高。     

PBO纤维的制备及性能研究

以4,6-二氨基间苯二酚盐酸盐-对苯二甲酸（DAR—TPA）盐为原料,多聚磷酸（PPA）为溶剂,制备了分子量较高的PBO聚合物纺丝液。通过液晶纺丝工艺制备PBO纤维,并对纺丝工艺对PBO纤维结构、性能的相关性影响进行了研究。研究结果表明,根据最优化条件制备的PBO纤维的拉伸强度为5．0GPa5．2GPa,拉伸模量为170GPa-180GPa,热分解温度为604℃,极限氧指数为67．9％。     

开孔泡沫金属压缩实化特性研究

对开孔泡沫金属微结构实化过程进行分析,理论分析表明开孔泡沫金属的实化应变不但与其相对密度成幂律关系,而且还与泡沫金属的单元结构特征密切相关.由此提出了一种用于描述相对密度较低的开孔泡沫金属压缩实化特性的数学模型,在该模型中泡沫结构和筋条材料对泡沫金属实化特性的影响以材料常数的形式体现,理论分析结果与试验结果完全一致.     

First Isolation and Characterization of Ochrobactrum anthropi from Pig

One Gram-negative Bacillus was isolated from a brain sample of a pig with neurological symptoms. Pathological examination showed meningitis at necropsy. Ochrobactrum anthropi (O. anthropi) was successfully isolated from the brain sample and was confirmed by biochemical reaction results (API 20 NE) and gene sequencing. The strain was highly resistant to β-lactam antibiotics. Mice were experimentally infected with O. anthropi and showed typical meningitis. This is the first report on O. anthropi isolated from a pig, and indicates that O. anthropi may have a broader host spectrum of infection.     

Modeling and Characterization of Grain Scale Strain Distribution in Polycrystalline Tantalum

A common sample geometry used to study shear localization is the "tophat": an axi-symmetric sample with an upper "hat" portion and a lower "brim" portion. The gage section lies between the hat and brim. The gage section length is on the order of 0.9 mm with deformation imposed through a Split-Hopkinson Pressure Bar system at maximum top-to-bottom velocity in the range of 10-25 m/sec. Detailed metallographic analysis has been performed on sections of the samples to quantify the topology and deformation state of the material after large deformation shear. These experiments performed with polycrystalline tantalum have been modeled using a multi-scale polycrystal plasticity approach. A Voronoi tessellation based microstructural model and a coupled thermo-mechanical elasto-viscoplastic crystal plasticity model was used. The crystal plasticity model allowed for slip to occur on the twelve {110}<111> and twelve {112}<111> slip systems. Three numerical models were produced using three different realizations of initial crystallographic texture distribution within the same morphological microstructure and the results presented. The detailed metallographic analysis of the deformed sample shear zone produced an estimate for the strain profile within that region and these results are compared directly to the three numerical simulation results. Although the models predict a stress response which is greater than that observed experimentally, the local strain response compares very well with the results of the metallographic analysis.