title: Cyprinodon bifasciatus fish gut viral metagenome sample from Cuatro Cienegas Basin
design: To extract viral particles from intestinal content of the three fish species (Hemichromis guttatus, Gambusia marshi, and Cyprinodon bifasciatus), 200  l of intestinal content was added to conical screw-cap tubes containing 100 mg of 150-212  m glass beads (Sigma, USA), chloroform (100  l), and PBS up to 1 ml. Samples were homogenized in a bead beater (Biospec Products, USA), centrifuged 10 minutes at 2,000 x g. Supernatants were recovered and filtered in Spin-X 22  m pore filters (Costar, NY, USA) at 5,000 x g during 10-20 minutes. Filtered samples were treated with Turbo DNAse (Ambion, USA) and RNAse (Sigma, USA) and extraction continued as water samples.