大肠菌群革兰氏染色技术的实验研究

通过比较实验，研究了在大肠菌群测定过程中菌龄、细菌密集程度、媒染时间、脱色程度等因素对革兰氏染色正确性的影响，从而得出了一最佳革兰氏染色条件组合，并提出了确保革兰氏染色技术操作正确的方法。     

高效阴离子交换-积分脉冲安培检测法测定巴龙霉素

巴龙霉素是一种氨基糖类抗生素,具有抵抗一些革兰氏阳性和革兰氏阴性菌的广谱活性,目前已被广泛用于治疗人类或者动物的细菌感染,例如人类的利什曼病、似隐胞菌素病和变形虫病.OneWorld健康组织将巴龙霉素定义为用来治疗罕见疾病的药物.     

地杆菌中基因Gmet＿1513对其产电及生物膜形成的影响

Geobacter metallireducens GS-15中存在Gmet＿1513基因可编码具有自动诱导结合域的LuxR家族转录调控因子，使GS-15借助N-酰基高丝氨酸内酯促进产电及生物膜形成成为可能.而目前有关地杆菌群感效应的相关研究大多基于投加化学信号分子或信号分子淬灭剂的手段，缺乏靶向性与精确性.本研究构建了Geobacter metallireducens GS-15的Gmet＿1513基因缺失突变株（Δgmet＿1513），研究Gmet＿1513在GS-15菌株发挥电活性过程中的功能.实验结果表明，Δgmet＿1513与野生型菌株相比产生群感效应信号分子的能力减弱，Δgmet＿1513外膜蛋白种类减少，生物电化学系统的启动时间延长且电流输出减弱.与此同时，激光共聚焦图像对比结果表明Δgmet＿1513无法形成成熟致密电活性生物膜，EPS成分显示Δgmet＿1513的蛋白质含量低，多糖、脂质含量高，使其电子产量低且转移困难，无法进行AHLs的识别及结合导致电子传递相关蛋白无法表达，电子传递多重受阻.本研究为今后以Gmet＿1513基因为靶标，利用群感效应相关蛋白表达调控地...     

Biodegradation of geosmin in drinking water by novel bacteria isolated from biologically active carbon

Three strains of Gram-negative bacteria capable of removing geosmin from drinking water were isolated from biologically active carbon and identified to be Chryseobacterium sp., Sinorhizobium sp. and Stenotrophomonas sp. based on physio-biochemistry analysis and 16S rRNA gene sequence analysis. Removal e ciencies of 2 mg/L geosmin in mineral salts medium were 84.0%, 80.2% and 74.4% for Chryseobacterium sp., Sinorhizobium sp. and Stenotrophomonas sp., respectively, while removal e ciencies of 560 ng/L geosmin in filter influent were 84.8%, 82.3% and 82.5%, respectively. The biodegradation of geosmin was determined to be a pseudo first-order reaction, with rate constants at 2 mg/L and 560 ng/L being 0.097 and 0.086 day??1, 0.089 and 0.084 day??1, 0.074 and 0.098 day??1 for the above mentioned degraders, respectively. The biomass of culture in the presence of geosmin was much higher than that in the absence of geosmin.     

适用于TGGE的微污染水体总DNA的提取方法比较

对比蛋白酶K-CTAB法、SDS-酚氯仿抽提法和试剂盒法对微污染水体总DNA的提取效果,进一步通过PCR-TGGE电泳及优势条带切胶测序分析,结果表明:SDS-酚氯仿抽提法提取水体总DNA效果最佳,试剂盒法次之,经纯化后均能扩增成功,蛋白酶K-CTAB法失败;SDS-酚氯仿抽提法比试剂盒方法的TGGE图谱条带数更多,代表的生物多样性更全面;试剂盒方法对革兰氏阳性菌的DNA提取能力不及SDS-酚氯仿抽提法。     

室内外环境中空气细菌的粒子大小分布

空气微生物污染的危害与其粒子大小分布密切相关,我们使用Andersen空气微生物采样器,对医院病房、实验室及动物房等处的室内环境,进行了空气细菌粒子大小分布的测定。结果表明,无论是空气细菌粒子大小的分布范围,中值直径,季节分布,还是革兰氏阳性球菌粒子大小的分布,室内空气中的细菌粒子都要比室外空气中的小并对其产生原因及其在疾病传播上的意义,做了初步的讨论。     

影响大肠菌群革兰氏染色的几个因素

无论在地表水环境质量评价还是在医院污水综合排放标准中,大肠菌群都是一项很重要的指标.在对大肠菌群测定过程中,革兰氏染色又是一步很重要的鉴定阶段,革兰氏染色的正确性直接关系到能否正确判断该菌落是不是大肠菌群,而革兰氏染色正是一门难以掌握的最基本的细菌学实验技术.现通过纯培养一株大肠杆菌(Escherchiacoli)并进行多种条件下的革兰氏染色,以观察革兰氏染色受哪些因素影响.     

大肠菌群革兰氏染色技术的实验研究

针对影响革兰氏染色正确性的几个因素,通过比较实验,研究了在大肠菌群测定过程中菌龄、细菌密集程度、媒染时间、脱色程度等因素对革兰氏染色正确性的影响,从而得出一最佳革兰氏染色条件组合,并提出了确证革兰氏染色技术操作正确的方法。     

降解氰化物细菌质粒的研究

从含KCN的分离筛选培养基上分离出的 2 0株菌株进行了质粒抽提 ,对质粒进行了限制性内切酶的酶切和琼脂糖凝胶电泳 ,发现了 1 1株细菌带有质粒 ,对其中几株带质粒菌和不带质粒菌进行了降氰力的测定 ,说明了质粒对降氰能力具有重要意义 ,并对 6株菌测定了质粒分子量 ,但未发现降氰力与分子量间的相关性。通过进行革兰氏染色发现 ,这 2 0株菌株都是革兰氏阴性杆菌 ,较好地说明了革兰氏阴性菌所普遍具有的降解能力。 更多还原      

Isolation and characterization of a thermophilic Bacillus shackletonii K5 from a biotrickling filter for the production of polyhydroxybutyrate

Polyhydroxyalkanoates（PHAs） are aliphatic polyesters accumulated intracellularly by both Gram-negative and Gram-positive bacteria. However, compared to the PHAs of Gramnegative bacteria, few endotoxins（lipopolysaccharides, LPS）, which would be co-purified with PHAs and cause immunogenic reactions, are found in the PHAs produced by Gram-positive bacteria. A thermophilic Gram-positive bacterium K5, which exhibited good growth and polyhydroxybutyrate（PHB）-accumulating ability, has been isolated and characterized from a biotrickling filter designed for the removal of NOx from flue gas in a coal-fired power plant in China. Based on the biochemical characterization and 16 S rRNA gene sequence（Genbank accession no. JX437933）, the strain K5 has been identified as Bacillus shackletonii, which has rarely been reported in the literature, and this report is the first time that B. shackletonii has been found to accumulate PHB. The strain K5 was able to utilize glucose as carbon source to synthesize PHB at a broad range of temperatures（from 35 to 50 °C）, and the ideal temperature was 45 °C. The strain K5 could effectively yield PHB of up to 69.9% of its cell dry weight（CDW）（2.28 g/L） in flask experiments employing glucose as carbon source at 45 °C, followed by 56.8% and 52.3% of its CDW when using sodium succinate and glycerol as carbon source, respectively. For batch cultivation, the strain K5 was able to produce PHB of up to 72.6% of its cell dry weight（9.76 g/L） employing glucose as carbon source at 45 °C and pH 7.0.