Phages and Genomic Variation in Vibrio Cholerae Evolution

描述（由申请人提供）：我们提出了一系列研究，以了解细菌病毒（噬菌体或噬菌体）在霍乱流行病学和霍乱弧菌进化中的作用。我们还希望了解霍乱流行区自然水环境的各个方面，这些方面影响对霍乱具有生物学意义的噬菌体介导和非噬菌体介导的事件。来自孟加拉国环境站点的弧菌噬菌体将被分离和表征。基因组微阵列将用于确定它们是否携带潜在的毒力基因。将对与霍乱弧菌基因组DNA杂交的噬菌体基因组进行测序，以了解其进化起源。我们将鉴定和表征由溶菌噬菌体在霍乱弧菌上生长产生的生物活性分子，该噬菌体被设计为对已知毒素和信号分子呈阴性。我们还将确定在适当的霍乱动物模型中，霍乱弧菌的感染剂量是否会受到影响。我们将测试TLC是携带毒素编码CTX噬菌体的附着位点的卫星噬菌体的理论。DNA转化的作用将通过寻找重组热点如超整合子和染色体岛来研究。我们还将尝试鉴定水中影响转化效率或噬菌体杀死霍乱弧菌的因素。我们将扩大已建立的环境水的双周档案，并研究水影响霍乱弧菌生物学特性的能力变化，如生物膜形成、优势细胞的产生和细菌的稳定性。将监测水中作为噬菌体替代宿主的非弧菌物种。这种宿主将作为环境监测的目标，以评估其作为促进水生环境内弧菌噬菌体“大量繁殖”的辅助因子的潜在作用，这反过来会对噬菌体敏感的流行性霍乱弧菌菌株的浓度产生有害影响。我们选择的参数的季节性波动可能是孟加拉国霍乱季节性的强有力的预测因子，从而有助于通过各种干预措施控制这种致命疾病。

DESCRIPTION (provided by applicant): We propose a series of studies to understand the role of bacterial viruses (vibriophage or phage) in cholera epidemiology and the evolution of Vibrio cholerae. We also hope to understand the aspects of the natural aquatic environment in a cholera endemic area that influence phage-mediated and non-phage mediated events that have biological significance to cholera. Vibriophages from Bangladesh environmental sites will be isolated and characterized. Genomic microarrays will be used to determine if they carry potential virulence genes. Phage genomes that hybridize with V. cholerae genomic DMA will be sequenced to understand their evolutionary origins. We will identify and characterize biologically active molecules produced by the growth of lytic vibriophages on V. cholerae engineered to be negative for known toxins and signaling molecules. We also will determine if phages influence the infectious dose of V. cholerae in appropriate animal models for cholera. We will test this theory that TLC is a satellite phage that carries the attachment site for the toxin- encoding CTX phage. The role of DNA transformation will be studied by looking for recombinational hot spots such as the superintegron and chromosomal islands. We will also attempt to identify factors in water that influence transformation efficiency or phage killing of V. cholerae. We will expand an established bi- weekly archive of environmental water and study variations in the water's ability to influence biological properties of V. cholerae such as biofilm formation, generation of domant cells, and stability of phages. Water will be monitored for a non-Vibrio species that acts as an alternative host for vibriophages. Such a host will be targeted for environmental surveillance in order to assess its potential role as a co-factor in promoting vibriophage "blooms" within aquatic environments which in turn should have a deleterious effect on the concentration of phage sensitive epidemic V. cholerae strains. The seasonal fluctuation of the parameters we selected may be strong predictors of cholera seasonality in Bangladesh and thus aid in the control of this deadly disease by a variety of interventions.