DNA virome from COVID-19 patient
Samples were centrifuged and filtered (0.45). DNase and RNAse were used to remove non-encapsidated nucleic acids. RNA/DNA Kits were used for extraction. cDNA was synthesized primers A1 (GTTTCCCAGTAGGTCTCN9) or B1 (GCCGGAGCTCTGCAGATATCN9).Second strand was generated by two rounds of synthesis with Sequenase or Klenow fragment polymerase, followed by 15 cycles of amplification using Phusion DNA polymerase with primer A2 (GTTTCCCAGTAGGTCTC), or 25 cycles of amplification wth primer B2 (GCCGGAGCTCTGCAGATATC). Nextera XT libraries were constructed for sequencing on an Illumina NextSeq 500 platform using 75-cycle or 300-cycle high-output kits to obtain paired-end reads.