一株牙Ping出血症病原菌的分子生物学鉴定

从患出血症养殖牙Ping分离到一株病原菌M4,革兰氏阴性,杆状,有极生和侧生鞭毛,能运动,菌落半透明。进行了常规生理生化和BIOLOG－GN细菌鉴定系统测试。结果表明菌株M4与V.carchariae的表型特征非常相似。为了进一步确定M4的分类学地位,测定了其16SrRNA基因序列,分析了相关细菌相应序列的同源性,构建了系统发生树,结果表明菌株M4和V.carchariae的亲缘关系最近。综合上述结果,菌株M4可鉴定为Vibiro carchariae。     

esaC基因对迟缓爱德华氏菌的毒力及T3SS蛋白分泌的影响

为了确定编码迟缓爱德华氏菌(E.tarda)Ⅲ型分泌系统(T3SS)装置蛋白的esaC基因的功能,采用基因敲除的方法构建了E.tarda野生型致病菌株LSFAO的esaC基因无极性缺失突变株LSE40ΔesaC,该突变株缺失了esaC的46-1452bp。Western blotting分析表明,由于esaC的缺失,E.tarda T3SS的输送器蛋白(EseB,EseC,EseD)不能分泌到细胞外,同时细菌的自凝聚现象消失;毒力检测发现,突变株LSE40ΔesaC对蓝曼龙鱼的半数致死量比野生型菌株提高了11.5倍。结果表明,esaC基因影响T3SS输送器蛋白的分泌和E.tarda的毒力。此研究确定了esaC基因作为E.tarda T3SS装置蛋白的功能,加深了对E.tarda致病机理的了解。     

16S rRNA基因与16S-23S rRNA转录单元内间隔区序列分析及其在节旋藻和螺旋藻分类鉴定中的应用

测定了节旋藻属3个品系和螺旋藻属1个品系的全长16SrRNA基因基因和16S rRNA转录单元内间隔区序列（ITS）,分析了已知的节旋藻、螺旋藻和相关品系的相应序列的同源性,构建了系统发生树,并评价了这两段DNA序列在节旋藻、螺旋藻种属分类和种质鉴定中的意义。结果表明：（1）16SrRNA基因序列和ITS序列均可用于节旋藻属和螺旋藻属的属间分类,以两序列为基础的系统学分析结果一致;（2）ITS序列变异程度高于16SrRNA序列,适用于节旋藻和螺旋藻属内品系或种质鉴定;（3）节旋藻属可明确界定,16SrRNA基因序列相似性大于98％,ITS序列相 似性大于88％;（4）螺旋藻属某些品系间16SrRNA序列和ITS序列相似性较低,与不同属间的序列相似性程度为同一水平。     

高效降解苯胺的菌株AD9的分离、生理生化特性分析和分子鉴定

从活性污泥中分离到一株能以苯胺为唯一碳源、氮源生长的苯胺降解菌株AD9,该菌株最适生长的苯胺浓度为1000mg／L,降解效率可达90％,对苯胺耐受程度高达4500mg/L,降解苯胺的最适pH值为7．0,最适温度为30℃。以上实验结果表明,AD9具有降解苯胺速率快、耐受苯胺浓度高的特性。该菌具有氨苄青霉素、卡那霉素和利福平抗性,无氯霉素、四环素抗性,其16SrDNA序列与多株Delftia sp．菌有很高的同源性,其G＋C含量为66．8mol％,非常接近于标准菌株D．tsuruhatensis T7（66．2mol％）。另外该菌和17的DNA-DNA杂交率为83．8％。结合AD9的表型鉴定将该菌株归属为D．tsuruhatensisas。这是D．tsuruhatensis菌种苯胺降解细菌菌株的首次报道。     

一株牙鲆出血症病原菌的分子生物学鉴定

从患出血症养殖牙鲆分离到一株病原菌M4,革兰氏阴性,杆状,有极生和侧生鞭毛 ,能运动,菌落半透明.进行了常规生理生化和BIOLOG-GN细菌鉴定系统测试,结果表明菌株M4与V.carchariae的表型特征非常相似.为了进一步确定M4的分类学地位,测定了其 16S rRNA基因序列,分析了相关细菌相应序列的同源性,构建了系统发生树,结果表明菌株M4与 V.carchariae的亲缘关系最近.综合上述结果,菌株M4可鉴定为Vibiro carchariae .     

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。     

青岛和大连海区海带(Laminaria japonica)外生细菌的16S rRNA基因序列分析

从采集自青岛和大连的大型褐藻海带(Laminaria japonica)表面分离到22株革兰氏阴性海洋细菌。根据16SrRNA基因序列分析结果,将其分别鉴定为假交替单胞菌(Pseudoalteromonas,Cobetia)菌,嗜冷单胞菌(Psychromonas),交替单胞菌(Alteromonas),产碱杆菌(Alcaligens)和海杆菌(Marinobacter)。其中假交替单胞菌在两地样品中占据绝对优势,但每个产地的假交替单胞菌不能单独聚类在一起,不同海区的海带表面存在遗传关系非常接近的菌株。假交替单胞菌之外的其他菌株于两地样品之间存在种或属水平上的差异。本文结果提示外生细菌的种类既与环境相关,又受宿主的状况影响。对8株受试菌株的拮抗实验结果显示了外生细菌在寻找新型抗生素方面的潜力。     

一株新硫醇脱臭菌的降解机能研究

从多菌源经富集分离出一株高效降解硫醇臭气的菌株(JLL),通过16S rRNA基因序列分析法和传统的生理生化法相结合,鉴定JLL为黄杆菌属的新种。经洗涤法降解实验分析JLL对硫醇气体的降解机理,并对JLL采用碱裂解法未提出质粒,基本可以确定菌株JLL不含质粒,其降解基因在染色体上,降解过程为染色体控制。     

大菱鲆病原鳗弧菌生物学及分子特征研究

从山东沿海养殖发病大菱鲆分离了5株鳗弧菌。5株菌对大菱鲆有较强的致病性,LD50范围为2.32×101～4.03×102cfu/g鱼;5株菌分别属于O1、O2、O3血清型,菌株之间的16SrRNA基因序列相似性范围97.1%～99.9%;与国外报道的鳗弧菌的序列相似性范围为89.7%～99.9%。5株菌的生理生化特征与鳗弧菌标准菌株一致,能产生多种胞外酶和溶血素;都含有金属蛋白酶基因和溶血素基因,其中3株菌各含有一个67kb大质粒。病原菌对青霉素、苯唑青霉素、氨苄青霉素、先锋霉素Ⅳ、先锋霉素Ⅴ、先锋霉素Ⅵ、链霉素、强力霉素、洁霉素、万古霉素、灭滴灵等11种常用抗菌药物有抗性,只对新生霉素、呋喃妥因、利福平、新霉素等4种药物敏感。     

海洋有益菌的筛选与鉴定

从健康的斑节对虾（Penaeus monodon）幼体及其养殖环境中分离到213株海洋细菌,采用十字叉划线法和琼脂扩散法进行体外拮抗试验,从中筛选到5株对水产养殖动物病原哈维氏弧菌（Vibro harueyi）和鳗弧菌（Vibrio anguillarum）等菌株生长有抑制作用的海洋细菌。根据其形态特征以及生理生化反应特征,初步鉴定为交替单胞菌属（Alteromonas）,其中菌株A18鉴定为橙色交替单胞菌（Alteromonas aurantia）。     

Application of a continuously stirred tank bioreactor (CSTR) for bioremediation of hydrocarbon-rich industrial wastewater effluents

A continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioprocess system in order to treat hydrocarbon-rich industrial wastewaters. A successful bioremediation was developed by an efficient acclimatized microbial consortium. After an experimental period of 225 days, the process was shown to be highly efficient in decontaminating the wastewater. The performance of the bioaugmented reactor was demonstrated by the reduction of COD rates up to 95%. The residual total petroleum hydrocarbon (TPH) decreased from 320 mg TPH l(-1) to 8 mg TPH l(-1). Analysis using gas chromatography-mass spectrometry (GC-MS) identified 26 hydrocarbons. The use of the mixed cultures demonstrated high degradation performance for hydrocarbons range n-alkanes (C10-C35). Six microbial isolates from the CSTR were characterized and species identification was confirmed by sequencing the 16S rRNA genes. The partial 16S rRNA gene sequences demonstrated that 5 strains were closely related to Aeromonas punctata (Aeromonas caviae), Bacillus cereus, Ochrobactrum intermedium, Stenotrophomonas maltophilia and Rhodococcus sp. The 6th isolate was affiliated to genera Achromobacter. Besides, the treated wastewater could be considered as non toxic according to the phytotoxicity test since the germination index of Lepidium sativum ranged between 57 and 95%. The treatment provided satisfactory results and presents a feasible technology for the treatment of hydrocarbon-rich wastewater from petrochemical industries and petroleum refineries.     

Comparative assessment upon dye removal capability of indigenous bacterial strains from Lanyang Plain in northeast Taiwan

This study provides a first attempt from a geological and ecological perspective to look forward isolations of indigenous strains with the decolorization capability from the most biodiverse region in Taiwan for dye-laden wastewater treatment. Serial selections were conducted by a specific use of the fungicide nystatin and model azo dye C.I. reactive red 141 (RR141) during isolation. Several bacterial strains with the excellent capability of azo dye decolorization were predominantly isolated from river water and mud samples of Lanyang River Basin. Phase-curve profiles indicated that azo dye decolorization was found to be non-growth associated for both mixed cultures and isolated pure strains. The color removal efficiency of the mixed culture was nearly 10-fold to that of Pseudomonas luteola at ca. 600mgL(-1) RR141, indicating a promising feasibility of isolated cultures to be applicable for practical treatments. The decolorization performance of unacclimated and acclimated pure cultures was at most 20% and 70-80% to that of the mixed cultures, respectively. It might suggest that combined interactions among decolorizers were crucial for the optimal color removal. According to the results of physiological and 16S rRNA gene sequence examinations, the isolated strains should belong to Aeromonas species (very likely A. hydrophila).     

Isolation and characterization of the heavy metal resistant bacteria CCNWRS33-2 isolated from root nodule of Lespedeza cuneata in gold mine tailings in China

A total of 108 strains of bacteria were isolated from root nodules of wild legumes growing in gold mine tailings in northwest of China and were tested for heavy metal resistance. The results showed that the bacterial strain CCNWRS33-2 isolated from Lespedeza cuneata was highly resistant to copper, cadmium, lead and zinc. The strain had a relatively high mean specific growth rate under each heavy metal stress test and exhibited a high degree of bioaccumulation ability. The partial sequence of the copper resistance gene copA was amplified from the strain and a sequence comparison with our Cu-resistant PCR fragment showed a high homology with Cu-resistant genes from other bacteria. Phylogenetic analysis based on the 16S rRNA gene sequence showed that CCNWRS33-2 belongs to the Rhizobium-Agrobacterium branch and it had 98.9% similarity to Agrobactrium tumefaciens LMG196.     

北极耐冷假交替单胞菌的培养温度对其胞外蛋白酶合成的影响

从北极楚科奇海水中分离筛选到2株产蛋白酶耐冷细菌BSw20308及BSw20353.经分子鉴定为假交替单胞菌属.这2株菌虽存在较近亲缘关系,16S rDNA序列相似性为98%,但属于不同种,表型方面也存在差异.酶谱分析显示,此2株菌的胞外产物中存在至少3种蛋白水解活性组分.培养温度的变化对这2株菌胞外蛋白水解活性组分的生成具有不同的影响效果,表明极地海洋细菌可能在酶学水平上通过酶的种类与活力的调整和采取不同的策略来适应环境温度的变化.     

Rapid detection of urinary tract infections using isotachophoresis and molecular beacons

We present a novel assay for rapid detection and identification of bacterial urinary tract infections using isotachophoresis (ITP) and molecular beacons. We applied on-chip ITP to extract and focus 16S rRNA directly from bacterial lysate and used molecular beacons to achieve detection of bacteria specific sequences. We demonstrated detection of E. coli in bacteria cultures as well as in patient urine samples in the clinically relevant range 1E6-1E8 cfu/mL. For bacterial cultures we further demonstrate quantification in this range. The assay requires minimal sample preparation (a single centrifugation and dilution), and can be completed, from beginning of lysing to detection, in under 15 min. We believe that the principles presented here can be used for design of other rapid diagnostics or detection methods for pathogenic diseases.     

Isolation and characterization of a Cr(VI)-reduction Ochrobactrum sp. strain CSCr-3 from chromium landfill

A strain CSCr-3 with high Cr(VI)-reducing ability under alkaline conditions was isolated from a chromium landfill and identified as Ochrobactrum sp. on the basis of 16S rRNA gene sequence analysis. The cells were rod shaped, Gram-negative and motile. The physiological characteristics and Cr(VI)-reduction of the strain were also studied. The results showed that the Ochrobactrum sp. strain CSCr-3 was tolerant to very high concentration of Cr(VI) (800 mg/L) and capable of reducing different forms of Cr(VI) (chromate and dichromate), under a wide range of temperatures (25-40 degrees C) and pH (7-11) with optimum at 35 degrees C and initial pH 10. Higher rates of Cr(VI)-reduction were observed with higher initial cell and Cr(VI) concentrations. Strain CSCr-3 could reduce Cr(VI) very efficiently over a wide range of Cr(VI) concentrations (100-800 mg/L). The addition of glucose caused a dramatic increase in Cr(VI)-reduction by Ochrobactrum sp. CSCr-3, while the presence of sulfate or nitrate had no influence. The presence of other metals, such as Cu, Co, Mn, etc., significantly stimulated Cr(VI)-reduction ability by the strain CSCr-3. The results obtained in this study have significance for the bioremediation of chromate pollution.