一株产黑色素海洋细菌的筛选、鉴定及发酵条件优化

从山东近岸海域海水中分离得到一株产黑色素细菌Sl,通过对S1菌株的菌落形态观察、生理生化性质检验及16SrDNA序列测定,初步鉴定为明亮发光杆菌(Photobacterium phosphoreum).为了提高S1菌株黑色素产量,采用单因素实验设计对S1菌株进行发酵条件优化,结果表明当发酵条件为L-酪氨酸0.75 g/...     

一株产黑褐色色素海洋放线菌的研究

从舟山群岛潮间带海域中分离到一批产色素的海洋放线菌,用滤纸片法进行抑菌试验,并对目标菌株进行鉴定,然后对其所产色素进行粗提,测色素的最大吸收波长,研究理化因子对其影响.结果表明筛选到产黑褐色色素的菌株B2,其对Vibrio parahaemolyticus和Escherichia coli具有较好的抑制作用,色素初步研...     

二株产壳聚糖酶海洋微生物的筛选和鉴定

采用不同培养基对海水养殖场环境样品进行壳聚糖酶产生菌的分离,结果表明海水培养基对于菌株筛选有显著的促进作用,同时甲壳类外壳是壳聚糖酶产生菌的良好来源。KJT-A和KJT-D是从海水养殖场蟹壳表面分离到的两株壳聚糖酶产生菌株,结合形态学观察、生理生化反应和分子生物学鉴定,初步确定菌株KJT-A和KJT-D分别为假单胞菌属(Pseudo-monas)和青霉属(Penicillium)。同时分析了不同温度、盐度对两株菌株生长的影响。     

一株嗜酸硫氧化细菌的分离鉴定及生长特性

从北京清河污泥中分离出一株硫氧化细菌,命名为QH-1,并对该菌株进行了分离鉴定.同时,初步研究了该菌株对几种重金属离子的耐受能力.结果发现,该菌株为革兰氏阴性,短杆状,需氧型,可从氧化还原态的硫元素中获得能量.QH-1菌株具有很好的产酸和耐酸能力,培养24h后pH即可下降到2.0,1周内可达到1.0以下,对数生长期为15d,进入稳定期时pH降为0.6.QH-1菌株的16S rRNA基因测序与分析表明,该菌株与Acidithiobacillus thiooxidans strain AAU具有99%以上的16S rRNA基因序列相似性.通过构建该菌株在相关种属中的系统发育树,并结合形态与生理生化特征分析,将QH-1菌株鉴定为氧化硫嗜酸硫杆菌(Acidithiobacillus thiooxidans).QH-1菌株对Zn2+和Cu2+有一定的耐受性,对Mo2+的耐受性较差.     

一株纤维素降解菌株的分离鉴定及产酶特征研究

利用纤维素为唯一碳源的选择性培养基,通过平板分离法,从造纸废水处理池中分离出一株产纤维素酶菌株。经菌落及菌的形态观察,生理生化实验和16SrDNA鉴定,判断其为一株荧光假单胞菌,被命名为Pseudomonas fluorescens sp.strainYL。通过其生长曲线和产酶动力学研究,对数期比生长速率约为0.125h-1。纤维素酶的产生与细菌的生长紧密相关联。该菌在摇瓶培养中以微晶纤维素唯一碳源时,粗酶液的最高CMC酶活出现在培养78h,达到17.12U/mL。然而以微晶纤维素和葡萄糖作为复合碳源时产酶活性最高,70h左右达92.3U/mL,而以蔗糖作为碳源时活性很小。这些结果表明:仅具有还原性基团的低聚糖才可诱导产纤维素酶,大分子纤维素对酶的诱导表达效果不及小分子还原糖,其酶的诱导生成可能是通过小分子还原糖间接实现的。     

Bacterial diversity in Fez tanneries and Morocco’s Binlamdoune River, using 16S RNA gene based fingerprinting

Tannery wastewater causes serious ecological and sanitary damage. Chemical analysis of water from Binlamdoune River of the medina of Fez was conducted and the results revealed the presence of toxic elements from tanneries and other industrial activities, which strongly a ected water quality. To determine the e ectiveness of bioremediation for depollution, we studied the abundance and diversity of bacteria residing in these polluted environments. Conducting denaturing gradient gel electrophoresis (PCR-DGGE) of the 16S rDNA area using primers related to bacteria showed a bacterial community belonging to eubacterial groups, that is, Epsilonproteobacteria, Clostridia, Lactobacillales, Bacteroidetes, Gammaproteobacteria, and Alphaproteobacteria. In addition, cloning displayed the presence of clones belonging to the Firmicutes group. Moreover, scanning electron microscopy revealed a significant heterogeneity of microorganism forms and structures. These endogenous microbes could have a significant role in the purification of Binlamdoune River and Fez tannery wastewater.     

海洋沉积物中反硝化细菌的分离鉴定及反硝化性能研究

利用良好的通气条件对反硝化细菌进行富集筛选,同时利用二苯胺试剂和Griess试剂显色反应分别检测NO₃--N的降解和NO₂--N的产生情况,并结合产气量筛选出具有良好耐氧性且反硝化性能优异的菌株. 最终从南海海域沉积物中筛选得到具有较强反硝化能力的细菌,并对目的菌株进行分子鉴定及反硝化能力测试. 结果表明,目的菌株F-8-1能较好地降解培养基中的NO₃--N和NO₂--N,产气快. 气相色谱检测发现,气体样品中的φ(N₂)非常高,接近100%,且未检测出其他氮氧化物气体. 16S rDNA序列分析表明,菌株F-8-1与假单胞菌属具有99%的序列相似性和很高的同源性.菌株F-8-1在有氧及高盐环境中生长良好.      

Evidences showing 2,4-D ethyl ester and pencycuron-induced DNA damage in cyanobacteria and detection by PCR

The impact of 2,4-D ethyl ester and pencycuron in inducing DNA damage in three species of cyanobacteria-Anabaena fertilissima, Aulosira fertilissima, and Westiellopsis prolifica as evidenced by PCR-based assays: RAPD and 16S rRNA amplification was examined. Exposure of genomic DNA (in vitro) to pencycuron for 4 days did not produce severe damage in DNA fragments of all three cyanobacterial species whereas exposure to 2,4-D ethyl ester markedly inhibited the template activity of genomic DNA compared to untreated cultures of A. fertilissima. In A. fertilissima a single band of approximately 1000?bp was observed even after 16 days of exposure to 60?ppm pencycuron which suggests that certain segments of DNA are resistant to pencycuron DNA damaging effects. However, a significant effect was observed in the case of W. prolifica for 2,4-D ethyl ester and pencycuron where complete disappearance of fragments was not recorded even after 16 days of incubation and interestingly some new DNA bands were induced. Similar to the effects with RAPD profile, amplification of rRNA was significantly inhibited following exposure of genomic DNA to 2,4-D ethyl ester and pencycuron. Our findings clearly demonstrate that pesticide concentrations affected cyanobacterial DNA and lethality of these microbes might be due to irreversible DNA damage. Thus, it is postulated that PCR assays may be conveniently used for screening DNA damage produced by 2,4-D ethyl ester and pencycuron in all three cyanobacteria examined in this study.     

抚顺西露天油页岩可培养微生物的分离与鉴定

为了解油页岩中可培养微生物的多样性,利用稀释平板培养法对我国抚顺盆地西露天组油页岩中可培养微生物进行分离纯化,并对所获菌株进行16S rDNA(细菌)和rDNA ITS(真菌)序列测定和系统发育树分析.以营养琼脂培养基分离到8株细菌,以马铃薯葡萄糖琼脂培养基分离到4株真菌.16S rDNA序列测定结果表明细菌菌株属于芽孢杆菌属(Bacillus),赖氨酸芽孢杆菌属(Lysinibacillus),短杆菌属(Brevibacillus),类芽胞杆菌属(Paenibacillus)和红球菌属(Rhodococcus); rDNA ITS序列测定结果显示真菌菌株分别属于芽枝霉属(Cladosporium),曲霉属(Aspergillus),犁头霉属(Absidia)和正青霉属(Eupenicillium). 2株细菌(ZK4和ZK5)能够在以油页岩为唯一碳源和氮源的固体培养基上连续生长5代以上,且长势良好, 可作为油页岩生物转化的潜力菌株进行深入研究.     

Isolation and characterisation of cadmium-resistant bacteria from an industrially polluted coastal ecosystem on the southeast coast of India

A total of 35 bacterial strains were isolated from the industrially polluted Cuddalore coast, on the southeast coast of India. Of these, 17 strains were cadmium resistant and the remainder were sensitive. Six strains (C-1, C-8, C-10, C-12, C-14 and N-1) were selected based on high levels of cadmium tolerance (>150 mg L^?1) and were termed highly cadmium-resistant bacteria (HCRB). These HCRB were identified on the basis of morphological, biochemical and partial sequencing of their 16S rRNA genes. The antibiotic-susceptibility patterns and minimum inhibitory concentrations (MIC) of different metals (Cu²⁺, Pb²⁺ and Zn²⁺) against each HCRB were determined. Among the isolates, C-14 showed high degrees of metal and antibiotic resistance compared with other HCRB. Growth rates of HCRB at two different Cd²⁺ concentrations (50 and 100 mg L^?1) and under different metal conditions (Cd²⁺, Cu²⁺ and Pb²⁺) were also investigated. HCRB growth rates were lower in the metal-treated condition than in the untreated condition. Isolates C-14 and N-1 removed>80% of Cd²⁺ from cadmium-treated broth. However, isolate C-14 removed 92.3% of Cd²⁺ compared with 86.5% for isolate N-1. Bacteria showing residual growth rates under metal stress conditions might be useful in metal removal applications under growing conditions.