HORIZONTAL GENE EXCHANGE AND GENOME EVOLUTION OF MYOVIRUSES IN AN AQUATIC ENVIRO

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 噬菌体是许多细菌病原体致病的原因。噬菌体编码的毒力因子包括致病菌株中的志贺毒素、霍乱弧菌中的霍乱毒素和肉毒杆菌中的肉毒杆菌神经毒素。噬菌体可以通过毒力因子的水平转移来驱动新的致病菌株的出现和进化，因此了解噬菌体基因组的进化具有重要的公共卫生意义。这项研究项目考察了水生环境中噬菌体基因组的遗传结构、动力学和进化。我们将检验这一假设，即目前的许多噬菌体多样性可以归因于最近发生的水平基因交换事件。一个自然的Myoviridae家族水生噬菌体群落正在被开发为一个模型系统，以解决噬菌体基因组进化的问题。正在从过去九年中分离的噬菌体以及从纳拉甘西特湾获得的新分离株中对核心病毒和宿主来源的基因进行测序。生物信息学工具正被用来分析这些序列：(1)构建系统发育基因和基因组树，(2)比较基因之间的相对分歧率，(3)检测和记录水平基因转移事件，以及(4)评估噬菌体之间以及噬菌体与其宿主之间可能进行的遗传交换的数量。这些噬菌体携带来自宿主、其他噬菌体或共同基因库的过量遗传物质的能力正在使用脉冲场凝胶电泳法进行评估。本科生参与研究的方方面面。这个试点项目是在暑假和学年对本科生进行生物医学研究中使用的关键分子基因技术的培训。学生将在完成个人项目时获得科学交流、实验室技术、关键仪器的使用和生物信息学方面的经验。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Bacteriophages are responsible for the virulence of many bacterial pathogens. Phage-encoded virulence factors include the shiga toxins in pathogenic strains of Escherichia coli, the cholera toxin in Vibrio cholerae, and the botulinum neurotoxins in Clostridium botulinum. Bacteriophages can drive the emergence and evolution of new pathogenic bacterial strains by the horizontal transfer of virulence factors and thus an understanding of bacteriophage genome evolution has important public health implications. This research project examines the genetic structure, dynamics, and evolution of bacteriophage genomes in an aquatic environment. We will test the hypothesis that much of the current bacteriophage diversity can be attributed to horizontal genetic exchange events that occurred recently. A natural community of aquatic bacteriophages in the Myoviridae family is being developed as a model system to address questions about bacteriophage genome evolution. Core-viral and host-derived genes are being sequenced from bacteriophages isolated over the past nine years as well as from new isolates obtained from Narragansett Bay. Bioinformatic tools are being used to analyze these sequences to: (1) construct phylogenetic gene and genome trees, (2) compare relative rates of divergence among genes, (3) detect and date horizontal gene transfer events, and (4) assess the number of possible genetic exchanges among phages and between phages and their hosts. The capability of these bacteriophages to carry excess genetic material derived from their hosts, other phages, or a common gene pool is being assessed using pulsed field gel electrophoresis. Undergraduate students participate in all aspects of the research. This pilot project is training undergraduate students both during the summer and the academic year in key molecular genetic techniques used in biomedical research. Students will gain experience in scientific communication, laboratory techniques, use of key instrumentation, and bioinformatics as they complete individual projects.