Role of the Horizontal Gene Pool and Lateral Gene Transfer in Enhancing Microbial Activities in Marine Sediments

摘要

To better understand plasmid distribution, diversity and abundance in marine sediment microbial communities we developed a number of methodological approaches to advance the field during this project. A new approach to facilitate the rapid comparison and differentiation of marine plasmids was developed using a randomly amplified polymorphic DNA (RAPD) approach. In addition to genotyping marine plasmids, this PCR-based method shows considerable promise for tracking spatial and temporal changes in marine plasmid populations. This method is applicable to other systems and can be used to type plasmids isolated from diverse microorganisms. We also continued our efforts optimize large-scale plasmid community extraction and isolation procedures that would provide enriched or purified supercoiled plasmid DNA from bulk marine sediments suitable for the construction of 'plasmid metagenome libraries'. Such libraries would provide access to the unculturable fraction of plasmids resident in marine microbial communities. These methods will provide new insights and understanding of bacterial gene flux mediated by marine plasmids.