Collaborative Research: CMG: Toward Understanding the Transfer of Genetic Information in Subsurface Hydrology

合作研究：CMG：了解地下水文学中遗传信息的传递

• 批准号: 0417555
• 负责人: John Cushman
• 金额: $ 21.39万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-10-01 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0417555&HistoricalAwards=false
• 关键词: Collaborative; Research; CMG; Toward; Understanding

Horizontal gene transfer among microorganisms is a critical process that impacts bacterial evolution over long time horizons as well as the spread of traits such as antibiotic resistance on short time scales. Recently there has been heightened public concern about the risk of gene transfer from genetically engineered organisms to indigenous organisms and its consequences. Many environmental microorganisms spend a large part of their viable life cycle in the porous medium of the natural subsurface, such as soils and aquifer materials. Because it is a natural filter for water the subsurface also provides a mixing zone for different strains of bacteria, that each partition between the aqueous and solid phases. Thus to understand the ramifications of horizontal gene transfer in the natural environment, it is important to study the interactions between different species as they undergo fate and transport in porous media. The primary goal of this project is to evaluate the kinetics of microbial attachment-detachment to porous media solid surfaces, and the coupled kinetics of horizontal gene transfer in porous media via conjugation. The green fluorescent protein (GFP) gene expression system will be used with known hosts and recipients originally isolated from soils to quantify rates of conjugative gene transfer in controlled micromodel experiments. The gene transfer is expected to be limited by the paired residence time of host and recipient cells together on solid surfaces, and so the distributions of these paired residence times and the distribution of gene transfer times will be compiled from the micromodel experiments. The model for these data will be crafted by combining a biased Levy motion with drift for the bacterial transport in the porous media, with an alpha-stable random variable for residence time attached to surfaces, with a non-Markovian reaction kinetic model for the gene transfer from host to recipient. The intellectual merit of this project arises from the coordinated collaboration of people with expertise in hydrology, microbiology, molecular biology, applied mathematics, and physics, to (1) adapt new tools in genetic analysis and microscopy to study microbial activity and gene exchange at a molecular level in micro flow chambers, and (2) use mathematics to extrapolate the findings to understand processes at higher scales in the subsurface. By combining experiment with theory we may be able to determine the major requirements for successful gene transfer. The broader impacts of this project arise from the wide applicability of the results to many areas including human health, disease propagation, medicine, contaminant remediation, and evolutionary biology. All of these phenomena involve the processes studied here, many in porous media (subsurface or biotic). Educationally the project provides the venue by which results from the collaborative study can be incorporated into the PI's undergraduate and graduate courses in microbiology, engineering, and mathematics. The PI's also have a solid record in involving minorities and women in research, via the MARC/AIM program at Purdue, and the Women In Engineering (nee' Women Engineering Link) program at UC Davis, and this habit will be continued in this project.

微生物之间的水平基因转移是一个关键过程，它会在长期范围内影响细菌的进化，并在短时间内影响抗生素耐药性等性状的传播。 最近，公众对从基因工程生物到本土生物的基因转移的风险及其后果越来越关注。 许多环境微生物的大部分生命周期都在自然地下的多孔介质中度过，例如土壤和含水层材料。 因为它是水的天然过滤器，所以地下还为不同细菌菌株提供了混合区域，每个细菌都在水相和固相之间进行分配。 因此，为了了解自然环境中水平基因转移的影响，研究不同物种在多孔介质中经历命运和运输时的相互作用非常重要。 该项目的主要目标是评估微生物在多孔介质固体表面上附着-脱离的动力学，以及通过接合在多孔介质中水平基因转移的耦合动力学。 绿色荧光蛋白（GFP）基因表达系统将与最初从土壤中分离的已知宿主和受体一起使用，以量化受控微模型实验中的接合基因转移率。 基因转移预计会受到宿主细胞和受体细胞在固体表面上的配对停留时间的限制，因此这些配对停留时间的分布和基因转移时间的分布将从微模型实验中编译出来。 这些数据的模型将通过将多孔介质中细菌运输的偏向 Levy 运动与漂移相结合、附着在表面上的停留时间的 α 稳定随机变量以及基因的非马尔可夫反应动力学模型来制作从主机传输到接收者。 该项目的智力价值源于具有水文学、微生物学、分子生物学、应用数学和物理学专业知识的人们的协调合作，以（1）采用遗传分析和显微镜学的新工具来研究微生物活动和基因交换微流室中的分子水平，以及（2）使用数学来推断研究结果，以了解地下更高尺度的过程。通过将实验与理论相结合，我们也许能够确定成功基因转移的主要要求。 该项目的更广泛影响源于其结果对许多领域的广泛适用性，包括人类健康、疾病传播、医学、污染物修复和进化生物学。 所有这些现象都涉及这里研究的过程，其中许多是在多孔介质（地下或生物）中。 在教育方面，该项目提供了一个平台，可以将合作研究的结果纳入 PI 的微生物学、工程和数学本科生和研究生课程中。 通过普渡大学的 MARC/AIM 项目和加州大学戴维斯分校的女性工程项目（nee' Women Engineering Link）项目，PI 在让少数族裔和女性参与研究方面也有着良好的记录，这一习惯将在本项目中得到延续。