title: Diversity and abundance of single-stranded DNA viruses in human feces.
abstract: In this study, we investigated the abundance and diversity of single-stranded DNA (ssDNA) viruses in fecal samples from five healthy individuals through a combination of serial filtration and CsCl gradient ultracentrifugation. Virus abundance ranged from 10⁸ to 10⁹ per gram of feces, and virus-to-bacterium ratios were much lower (less than 0.1) than those observed in aquatic environments (5 to 10). Viral DNA was extracted and randomly amplified using phi29 polymerase and analyzed through high-throughput 454 pyrosequencing. Among 400,133 sequences, an average of 86.2% viromes were previously uncharacterized in public databases. Among previously known viruses, double-stranded DNA podophages (52 to 74%), siphophages (11 to 30%), myophages (1 to 4%), and ssDNA microphages (3 to 9%) were major constituents of human fecal viromes. A phylogenetic analysis of 24 large contigs of microphages based on conserved capsid protein sequences revealed five distinct newly discovered evolutionary microphage groups that were distantly related to previously known microphages. Moreover, putative capsid protein sequences of five contigs were closely related to prophage-like sequences in the genomes of three Bacteroides and three Prevotella strains, suggesting that Bacteroides and Prevotella are the sources of infecting microphages in their hosts.
authors.affiliation: Department of Life and Nanopharmaceutical Sciences and Department of Biology, Kyung Hee University, 1 Hoegi-dong, Dongdaemun-gu, Seoul 130-701, Republic of Korea.
authors.forename: Min-Soo
authors.initials: MS
authors.lastname: Kim
authors.forename: Eun-Jin
authors.initials: EJ
authors.lastname: Park
authors.forename: Seong Woon
authors.initials: SW
authors.lastname: Roh
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Bae
mesh_terms: D044822:Biodiversity; D002499:Centrifugation, Density Gradient; D016000:Cluster Analysis; D004267:DNA Viruses / Q000235:genetics* / Q000302:isolation & purification*; D004277:DNA, Single-Stranded / Q000235:genetics* / Q000302:isolation & purification; D004279:DNA, Viral / Q000235:genetics* / Q000302:isolation & purification; D005243:Feces / Q000821:virology*; D005374:Filtration; D006801:Humans; D021141:Nucleic Acid Amplification Techniques; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D019562:Viral Load
chemical_list: D004277:DNA, Single-Stranded; D004279:DNA, Viral