Genetic and environmental factors driving E. coli attachment to particles in streams

1236510有害微生物是导致30万英里河流和海岸线以及500万英亩湖泊不符合美国水质标准的主要原因。 由于缺乏对微生物附着在颗粒上的机制的了解，模拟表面流中的微生物运输需要大量的假设。 细菌表达有利于附着的外膜特征的遗传倾向、有机颗粒或沉积物的理化特性、水化学或环境条件或这些因素的某种组合可能会影响对颗粒的附着。 该项目的目标是提高我们对影响E.大肠杆菌附着在有机颗粒和河流沉积物上。 本研究的目的是（1）评价E.（2）确定外膜蛋白和EPS对附着的影响，并鉴定这些特征的表达基因;（3）比较E. coli的附着和脱离行为。大肠杆菌具有明显的附着倾向;以及（4）评估大肠杆菌的机制。大肠杆菌对实际河流颗粒物的附着与对模型颗粒物的附着进行比较。我们将确定介导大肠杆菌的基因编码因子。大肠杆菌附着在环境颗粒上。 所有的发现都将通过基因缺失实验来证实，以验证在环境相关条件下所提出的附着介导基因对附着的作用。 实验将确定粒子特性，使E。大肠杆菌的附着和环境变化促进了大肠杆菌的分离。大肠杆菌从环境颗粒。 对E.大肠杆菌和颗粒物的研究是必要的，以提高对微生物环境归宿和迁移过程的理解和建模，这对于保护高质量的供水和确定可能存在公共健康风险的条件是重要的。 了解病原体如何流经河流对于预测公共卫生何时可能面临风险非常重要。 病原体在沃茨中移动时会附着在颗粒上，但尚不清楚这是因为细菌的遗传学、颗粒的特性还是微生物周围的环境。 本项目将探讨影响淡水溪流中病原体和颗粒之间相互作用的许多因素。 这一新知识将改进微生物归宿和迁移模型，这些模型经常用于流域尺度的水质评估。 我们还将为服务不足的少数民族中学生开发基于发现的学习模块，并为一些研究生和本科生提供教育机会。

1236510SoupirHarmful microorganisms are the leading cause of impairments in the 300,000 miles of rivers and shorelines and 5 million acres of lakes that do not meet U.S. water quality standards. Modeling microbial transport in surface streams requires numerous assumptions because of the lack of understanding about the mechanisms driving microbial attachment to particles. Attachment to particles may be influenced by a genetic predisposition of bacteria to express outer membrane features that facilitate attachment, by physiochemical characteristics of organic particles or sediments, by water chemistry or environmental conditions, or some combination of these factors. The goal of the project is to improve our understanding of the genetic and environmental factors influencing E. coli attachment to organic particles and stream sediments. The objectives of the project are to (1) evaluate the attachment of E. coli to model stream particles under environmentally relevant conditions and determine the relative contribution of surface proteins and EPS to this attachment; (2) determine the effect of outer membrane proteins and EPS on attachment and identify the genes enabling expression of these features; (3) compare attachment and detachment behavior of E. coli with a demonstrated propensity for attachment; and (4) assess the mechanisms of E. coli attachment to actual stream particulates by comparison with attachment to model particulates. We will identify genetically encoded factors that mediate E. coli attachment to environmental particles. All findings will be confirmed by gene deletion experiments to verify the role of proposed attachment-mediating genes on attachment under environmentally relevant conditions. Experiments will identify particle characteristics enabling E. coli attachment and environmental changes encouraging detachment of E. coli from environmental particles. The knowledge gained about the interactions between E. coli and particles is needed to improve understanding and modeling of microbial environmental fate and transport processes, which are important for the protection of high quality water supplies and identifying conditions when a risk to public health may be present. Understanding how pathogens flow through streams is important for predicting when public health might be at risk. Pathogens attach to particles when they move through waters, but it is unknown if this is because of the genetics of the bacteria, properties of the particle, or the environment surrounding the microorganism. This project will explore the many factors influencing the interactions between pathogens and particles in freshwater streams. This new knowledge will improve models of microorganism fate and transport, which are frequently used in watershed-scale, water quality assessments. We will also develop discovery-based learning modules for underserved minority middle school students and provide educational opportunities for several graduate and undergraduate students.