Qiaamp dna mini isolate kit

Genomic DNA extraction was performed for all 21 drinking water samples. Portions of each pellet obtained from the respective samples (see 'Water sample processing' section) were suspended by vortexing, and 300 µl of the sample was transferred directly into a 1.5 ml centrifuge tube and centrifuged for 2 minutes at 13,000 rpm and the supernatant was discarded. The sediment was re-suspended in 300 µl sterile distilled water and centrifuged at the same conditions three times repeatedly. The extraction was carried out using ve freeze-thaw (-70˚C) cycles followed by QIAamp DNA Mini isolate kit (Qiagen, Germany) in accordance with the original protocol. Then, the samples (200 µL each) were washed seven times with 1 mL of PBS (pH= 7.3) and centrifuged at 14000 g for 1 min. The pellets collected in the preceding steps were re-suspended in 1400 μl of buffer ASL, heated to 95°C for 10 min, then vortexed, and centrifuged at 15000 g for 1 min. The digestion process with proteinase K was elongated to 30 min at 70°C. DNA yields of each sample were determined from the concentration of DNA in the eluate, measured by absorbance at 260 nm. DNA purity was determined by calculating the ratio of absorbance at 260 nm to absorbance at 280 nm. DNA length was also determined by pulsed-eld gel electrophoresis through an agarose gel, and the genotyping process was performed accordingly.

The portions of each pellet was suspended by vortexing and 300 µl of the sample was transferred directly into a 1.5 ml centrifuge tube and centrifuged for 2 minutes at 13,000 rpm and the supernatant was discarded. The sediment was re-suspended in 300 µl sterile distilled water and centrifuged at the same conditions three times repeatedly. The extraction was carried out using ve freeze-thaw (- 70˚C) cycles followed by QIAamp DNA Mini isolate kit (Qiagen, Germany) in accordance with the original protocol. The samples were washed seven times with 1 mL of PBS (pH = 7.3) and centrifuged at 14000 g for 1 min. The pellets collected in the preceding steps were re-suspended in 1400 µl of buffer ASL, heated to 95 °C for 10 min, then vortexed, and centrifuged at 15000 g for 1 min. The digestion process with proteinase K was elongated to 30 min at 70 °C.