title: Viral metagenomics of swab samples from laboratory environment: Control05
design: In 2020, to investigate the virome of laboratory environment, 5 swab samples were collected from the surface of laboratory worktops, instruments and pipettes using DPBS-soaked swabs. All samples were collected by disposable materials. Then, the cotton tip of swab samples were re-suspended in 500 uL of Dulbecco's phosphate-buffered saline (DPBS) and vigorously vortexed for 5 min, following frozen and thawed three times on dry ice. The supernatants were then collected after centrifugation (10 min, 15,000 g). Totally, 500 uL of each supernatant was filtered through a 0.45 um filter (Millipore) to remove eukaryotic and bacterial cell-sized particles. The filtrates enriched in viral particles were treated with DNase and RNase to digest unprotected nucleic acid at 37C for 60 min. Remaining total nucleic acid was then isolated using QIAamp MinElute Virus Spin Kit (Qiagen) according to manufacturer's protocol. Five libraries were then constructed using Nextera XT DNA Sample Preparation Kit (Illumina) and sequenced using the Illumina Miseq platform with 250 bases paired ends and dual barcoding for each pool. For bioinformatics analysis, paired-end reads of 250 bp generated by Miseq were debarcoded using vendor software from Illumina.