PLoS ONE：寻找细菌致病基因或加速对莱姆病发病机理的探寻

近日，来自得克萨斯大学健康科学中心的研究者加速了他们对引发莱姆病细菌的基因的相关研究，这项研究或许会开发出新型的检测手段以及治疗莱姆病的疗法。莱姆病是由扁虱叮咬而出现麻疹、发烧等症状的一种传染性疾病。文章中，研究者开发出了一种新技术可以提高其检测细菌基因的速度，是原来检速度的15倍以上，相关研究成果刊登于国际杂志PLoS One上。

研究者希望利用这种新技术来揭开伯氏疏螺旋体引发莱姆病的原因，研究者认为随着研究的深入，对莱姆病的研究成果也会越来越多，会给患者带来巨大的帮助。在机体中，伯氏疏螺旋体可以侵入人类或者动物的任何组织中，并且引发长达数月或者数年的感染。研究者的长期目标就是去筛选、鉴别以及对引发莱姆病的细菌进行定性。

文章中，研究者对细菌1739个基因进行了检测筛查，来鉴别哪些基因可以影响细菌扩散疾病的能力。随后研究者对细菌的某些基因进行了突变，并且对细菌对小鼠模型的影响进行了测定。研究者分离并且鉴定了4479个细菌突变株，研究者使用新技术在较短时间内对敲除了细菌790个基因，有些基因进行了多次的敲除。这种新型筛选技术，包括信号标签突变、Luminex高通量筛查技术，可以被用于对其它引发感染的细菌的特殊基因进行鉴定。

研究者Charles Ericsson博士说，这项研究可以让我们在基本水平理解疾病的发病机理，比如理解疾病的毒力特性可以帮助我们开发出新型疫苗，或者诊断工具，抑或者是开发出新型的药物。

此前研究中，研究者Norris以细菌蛋白VlsE开发出了新型方法来对莱姆病进行有效诊断，包括对VlsE特异性抗体进行检测等，VlsE的特异性抗体是在莱姆病患者或动物体内所发现的。相关研究由美国国家过敏症和传染病研究所提供支持。

编译自：Scientists Step Up Hunt for Bacterial Genes Tied to Lyme Disease

doi:10.1371/journal.pone.0047532
PMC:
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Analysis of an Ordered, Comprehensive STM Mutant Library in Infectious Borrelia burgdorferi: Insights into the Genes Required for Mouse Infectivity

Tao Lin1*, Lihui Gao1, Chuhua Zhang1, Evelyn Odeh1, Mary B. Jacobs3, Loïc Coutte1¤, George Chaconas4, Mario T. Philipp3, Steven J. Norris1,2

The identification of genes important in the pathogenesis of Lyme disease Borrelia has been hampered by exceedingly low transformation rates in low-passage, infectious organisms. Using the infectious, moderately transformable B. burgdorferi derivative 5A18NP1 and signature-tagged versions of the Himar1 transposon vector pGKT, we have constructed a defined transposon library for the efficient genome-wide investigation of genes required for wild-type pathogenesis, in vitro growth, physiology, morphology, and plasmid replication. To facilitate analysis, the insertion sites of 4,479 transposon mutants were determined by sequencing. The transposon insertions were widely distributed across the entire B. burgdorferi genome, with an average of 2.68 unique insertion sites per kb DNA. The 10 linear plasmids and 9 circular plasmids had insertions in 33 to 100 percent of their predicted genes. In contrast, only 35% of genes in the 910 kb linear chromosome had incapacitating insertions; therefore, the remaining 601 chromosomal genes may represent essential gene candidates. In initial signature-tagged mutagenesis (STM) analyses, 434 mutants were examined at multiple tissue sites for infectivity in mice using a semi-quantitative, Luminex-based DNA detection method. Examples of genes found to be important in mouse infectivity included those involved in motility, chemotaxis, the phosphoenolpyruvate phosphotransferase system, and other transporters, as well as putative plasmid maintenance genes. Availability of this ordered STM library and a high-throughput screening method is expected to lead to efficient assessment of the roles of B. burgdorferi genes in the infectious cycle and pathogenesis of Lyme disease.

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