DNA Extraction from 0.22 μM Sterivex Filters and Cesium Chloride Density Gradient Centrifugation

Hi, I'm Jody from the laboratory, Steven Hallam in the Department of Microbiology in immunology at the University of British Columbia. Today we'll show you a procedure for extracting genomic DNA, concentrated from seawater samples onto 0.2 micron STX filters and a purification of this DNA by a cesium chloride density gradient centrifugation. We use this procedure in our laboratory to obtain environmental DNA so that we can study microbial community structure, diversity and metabolism in marine environments.

So let's get started. Begin this protocol by thawing on ice, the stir of X filters that you have previously concentrated with planktonic biomass, treated with lysis, buffer and frozen for simplicity. Here we describe the procedure for processing an individual filter.