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

几十年来，遗传信息在环境中的转移一直是科学家和公众关注的一个重要问题。随着对病原菌的抗生素耐药性的迅速传播，它的重要性首次显现出来。基因组分析表明，基因转移在细菌进化中发挥了重要作用。最近，公众对从基因工程生物向土著生物转移基因的风险以及可能对环境造成的后果表示关注。细胞之间的转移是基因在自然地质结构中传播到替代宿主的主要手段之一。尽管这一过程已被记录在案，交换发生在实验室条件下，但人们对这些事件在地下发生的频率知之甚少。自然地质环境是异质的，因此不可能在一系列尺度上对每一个变量进行实验测试。通过实验和理论相结合，研究人员的目标是确定成功基因转移的主要要求，以及在特定条件下发生这种转移的比率。环境中的细菌之间的遗传物质转移可以在浮游状态和附着状态下发生。这项研究侧重于数学的发展和应用，以描述与地下生物膜内水平基因转移相关的基本方面。用来描述细菌在多孔介质中传输的数学一直集中在单个细胞或细胞束传输的胶体传输机制上。到目前为止，这两个领域几乎完全孤立。在这里，研究人员提出了实验和建模，旨在测试有关在多个尺度上的多孔介质中传输的假设，并阐明控制传输、附着和生物膜形成的细菌之间传输的优先机制。

The transfer of genetic information in the environment has been an important issue among scientists and the public for several decades. Its importance first became apparent with the rapid spread of antibiotic resistance to pathogenic bacteria. Then genomic analysis revealed that gene transfer has played an important role in bacterial evolution. Recently there have been public concerns about risks associated with gene transfer from genetically engineered organisms to indigenous organisms and the possible consequences in the environment. Cell to cell transfer is one of the primary means by which genes can be propagated in natural geologic formations into alternate hosts. Although the process has been documented and exchange occurs under laboratory conditions, very little is known about the frequency of these events in the subsurface. The natural geologic environment is heterogeneous, and therefore it has been impossible to test every variable experimentally over a hierarchy of scales. By combining experiment with theory the investigators target identification of the major requirements for successful gene transfer and the rates at which it occurs under particular conditions. The transfer of genetic material among bacteria in the environment can occur both in the planktonic and attached state. This study focuses on the development and application of mathematics to describe the fundamental aspects associated with horizontal gene transfer within biofilms in the subsurface. The mathematics used to describe bacterial transport in porous media has been focused on colloid transport mechanisms for single cell or cell clump transport. These two fields are so far in nearly complete isolation from each other. Here the investigators propose experiments and modeling designed to test hypotheses regarding transfer in porous media at multiple scales, and to elucidate priority mechanisms controlling transfer among bacteria undergoing transport, attachment, and biofilm formation.