A multiplatform real-time polymerase chain reaction detection assay for Vibrio cholerae

We report a multiplatform real-time polymerase chain reaction methodology based on genes encoding for the regulatory toxR activator and enterotoxin A protein to determine enterotoxigenic Vibrio cholerae types from other vibrios. This assay, which was successfully validated on a collection of 87 bacterial strains, including 63 representatives of V. cholerae and 8 noncholera vibrios provides a rapid tool for detection and identification of cholera.     

The outer membrane protein,LamB (maltoporin), is a versatile vaccine candidate among the Vibrio species

Maltoporin (LamB) is a family of outer membrane proteins. There has been no report of immunological characteristics of LamB in the Vibrio species so far. In this study, lamB genes from eight Vibrio strains were cloned and sequenced. The bioinformatics analysis indicated that sequence similarities of LamB proteins were ranged from 46.7% to 81.1%. Further, the result showed that their antigenic epitopes were highly conserved implying that LamB might be a shared antigen among Vibrios. The Western blot of rabbit sera against recombinant LamB from V. alginolyticus ATCC 33787 with cell lysate of 18 Vibrio strains showed cross-recognition. Bands observed on cell lysate of Vibrio strains immunoblotted with the anti-LamB sera ranged between 40 and 49 kDa. The Whole-cell ELISA assay further confirmed that the antisera of recombinant LamB recognized the tested Vibrio strains indicating the surface-exposed of LamB. Finally, the cross-protective property of recombinant LamB was evaluated through vaccination and subsequent challenge with heterogeneous virulent Vibrio strains in zebrafish. Recorded relative percent survival (RPS) of the vaccinated group varied from 54.1% to 77.8%, showing that zebrafish were protected from Vibrio infection after immunization with LamB protein. The cumulative evidences in this study suggested that LamB was a conserved antigen among tested Vibrio species and might be a potentially versatile vaccine candidate for the prevention of Vibriosis.     

抗副溶血弧菌TLH蛋白多克隆抗体的制备及其ELISA双抗体夹心检测法的研究

目的分别制备抗副溶血弧菌及其不耐热溶血毒素(thermolabile hemolysin,TLH)的多克隆抗体,建立检测副溶血弧菌TLH的酶联免疫吸附试验(ELISA)双抗体夹心法。方法以副溶血弧菌及其TLH分别免疫健康雄性新西兰大白兔和雌性BALB/C小鼠,制备兔抗副溶血弧菌多克隆抗体及小鼠抗TLH多克隆抗体,以间接ELISA法检测两种抗体效价,并以棋盘法筛选两种多克隆抗体用于夹心检测TLH的效价。结果兔抗副溶血弧菌多克隆抗体效价达1∶6400,鼠抗TLH多克隆抗体效价为1∶102 400,经筛选确定以1∶800稀释的兔抗副溶血弧菌多克隆抗体包被酶标板,与1∶1600稀释的鼠抗TLH抗体建立了ELISA双抗体夹心法。结论兔抗副溶血弧菌多克隆抗体可与TLH呈特异性反应,以此建立的双抗体夹心法检测副溶血弧菌TLH可获较满意结果,此实验可为进一步建立简便、快速的副溶血弧菌检测方法奠定基础。     

海洋弧菌B2817的抗肿瘤活性成分研究

目的 对海洋弧茵B2817的抗肿瘤活性成分进行分离纯化和结构鉴定.方法采用溶剂萃取、制备HPLC等分离手段.对该菌株所产的活性成分进行了活性追踪分离.通过现代波谱学手段进行化学结构鏊定,以MTT法评价了化合物的抗肿瘤活性.结果从中分离得到4个化合物.分别鉴定为灵茵红素(1)、肉豆蔻酸(2)、7-十六碳烯酸(3)、7,10-十八碳二烯酸(4).化合物1对肿瘤细胞SM7721、S180具有强细胞毒活性.IC50分别为6.3、5.6μg·mL-1,而对人正常肝细胞HL-02无毒性.结论 4个化合物均为首次从该菌株中得到,而且弧菌B2817为灵茵红素的生产提供了新的来源.     

荧光PCR和PFGE在副溶血弧菌食物中毒诊断中的应用研究

[目的]探讨荧光PCR和脉冲场电泳（PFGE）在副溶血弧菌食物中毒调查中的应用。[方法]对中毒样品进行荧光PCR检测,副溶血弧菌临床分离株基因组DNA经NotI酶切,通过PFGE获得电泳图谱,利用BioNumerics软件对图谱进行聚类分析。[结果]部分样品荧光PCR检测结果呈阳性,同起食物中毒菌株PFGE图谱一致。[结论]荧光PCR可以快速准确的鉴定病原体。PFGE具有很强的菌株同源性分析能力,适用于食物中毒病原菌学鉴定和传染源溯源。荧光PCR和PFGE在食物中毒的快速诊断中可发挥重要作用。     

扩增片段长度多态性分析用于霍乱弧菌分子分型的方法建立和应用评价

目的建立霍乱弧菌的基于红外荧光标记引物的扩增片段长度多态性(AFLP)分型方法,评价脉冲场凝胶电泳(PFGE)和AFLP对霍乱弧菌的分型能力。方法选择PFGE带型均不相同的47株霍乱弧菌作为评价菌株,建立AFLP对于霍乱弧菌的分型方法;确定操作程序后选择83株分离自1962-2005年11个省的霍乱弧菌,进行AFLP和PFGE对于霍乱弧菌分型能力的比较。AFLP分型方法采用了红外荧光标记PCR引物,利用LI-COR4300自动测序仪完成电泳、SagaMX软件对电泳图谱进行编辑。PFGE采用PulseNet提供的标准化程序。结果AFLP用于霍乱弧菌分型时选择性引物携带碱基数为1,最优引物组合为EcoRⅠ-G／MseⅠ-T,AFLP分型实验的重复性达到99．2％。AFLP将83株霍乱弧菌分为52个型别,D值为0．9545;PFGE将此83株菌分为44种带型,D值为0．9251。结论优化固定了AFLP对于霍乱弧菌的分型程序,重复性好;AFLP比PFGE具有更好的分型能力,能够用于分离菌株的分子分型。结合已成为实验室网络监测标准分析方法的PFGE,可对分离株做更细致的分型比较。     

多重PCR与PCR-荧光探针法检测外环境霍乱弧菌的比较研究

目的：对比多重PCR与PCR-荧光探针法从外环境中直接检测霍乱弧菌的效果。方法：收集40份水样和40份水产品样本,再以20份已知特性菌株作对照。将上述样本和菌株进行培养后提取模板,分别进行多重PCR和PCR-荧光探针法检测。结果：两种方法均从40份水样中检出14份非O1非O139群霍乱弧菌,两种方法均能从40份水产品中检出29份O1群霍乱弧菌及3份非O1非O139群霍乱弧菌。以上检出霍乱弧菌均可经血清学试验证实。20份已知特性样本两种方法均鉴定无误,最低检出限均为10^2cfu/ml。结论：两种方法灵敏度和特异度均极高,多重PCR方法因能同时进行致病力的初步判断,检验速度相对较快,成本较为经济而更为实用。     

霍乱弧菌O139和El Tor菌株tcpA分子特征的研究

[目的]从霍乱弧菌XJ93006、MO45、XJ89079中克隆毒素协同调节菌毛亚单位A（tcpA）基因（包括侧序列）并测序比较。[方法]PCR扩增tcpA片段;克隆该片段;提取质粒经鉴定后测序并利用DNAMAN对该序列进行序列分析,比较。[结果]成功构建XJ93006、MO45、XJ89079 tcpA基因的重组质粒。三株霍乱弧菌及与N16961 tcpA基因及其两侧核酸序列同源性XJ89079和N16961为100%,XJ93006和XJ89079为99.8%,XJ93006和MO45为99.5%,XJ89079和MO45为99.7%。[结论]该研究初步认为我国新疆VC O139与本地EVC关系密切。     

O139群霍乱弧菌16S rRNA基因分型分析

[目的]研究北京市O139群霍乱弧菌的分子生物学特征。[方法]对北京市1998～2000年的30株O139群霍乱弧菌进行PCR霍乱肠毒素（CT）基因检测,以16SrRNA为探针对菌株DNA进行Southern杂交后对图谱进行核糖体基因（RT）分型分析。[结果]对30株霍乱弧菌RT图谱进行分析,共存在5种16SrRNA核糖体基因型,其中CT阳性的O139群霍乱弧菌为RT1型,CT阴性的O139群霍乱弧菌为RT2-RT5型。[结论]北京市不同年份的O139群霍乱弧菌CT阳性菌株核糖体基因型较为单一,CT阴性菌株基因型具有明显的多样性。提示北京市O139群霍乱弧菌CT阳性菌株和CT阴性菌株遗传发生上相距较远。