For the U.S. and Dominican Republic fecal samples, bacterial DNA was extracted from approximately 1 g of material using a QIAmp DNA stool minikit according to the manufacturer’s instructions (Qiagen, Valencia, CA) as described (25 (link)). About 200 mg of Australian stool samples was extracted using the QIAmp stool DNA kit, while about 500 mg of dry fecal sample for French samples was extracted using the FastDNA spin kit for soil (MP Biomedicals, Carlsbad, CA). Australian and French extracted DNA was freeze-dried before being shipped to the United States.
In total, 25 ml for sewage influent and between 200 and 400 ml for freshwater samples was filtered onto 0.22-μm mixed cellulose ester filters with a 47-mm diameter (Millipore, USA). DNA from filters was then extracted using the FastDNA spin kit for soil (MP Biomedicals, Solon, OH) as previously described (26 (link), 36 (link)). DNA concentration was assessed on a Qubit 2.0 fluorometer (Invitrogen, Carlsbad, CA).
In total, 25 ml for sewage influent and between 200 and 400 ml for freshwater samples was filtered onto 0.22-μm mixed cellulose ester filters with a 47-mm diameter (Millipore, USA). DNA from filters was then extracted using the FastDNA spin kit for soil (MP Biomedicals, Solon, OH) as previously described (26 (link), 36 (link)). DNA concentration was assessed on a Qubit 2.0 fluorometer (Invitrogen, Carlsbad, CA).
Free full text: Click here
