title: Isolation and characterization of a virus (CvV-BW1) that infects symbiotic algae of Paramecium bursaria in Lake Biwa, Japan.
abstract: BACKGROUND
  We performed an environmental study of viruses infecting the symbiotic single-celled algae of Paramecium bursaria (Paramecium bursaria Chlorella virus, PBCV) in Lake Biwa, the largest lake in Japan. The viruses detected were all Chlorella variabilis virus (CvV = NC64A virus). One of them, designated CvV-BW1, was subjected to further characterization.
  
  
  RESULTS
  CvV-BW1 formed small plaques and had a linear DNA genome of 370 kb, as judged by pulsed-field gel electrophoresis. Restriction analysis indicated that CvV-BW1 DNA belongs to group H, one of the most resistant groups among CvV DNAs. Based on a phylogenetic tree constructed using the dnapol gene, CvV was classified into two clades, A and B. CvV-BW1 belonged to clade B, in contrast to all previously identified virus strains of group H that belonged to clade A.
  
  
  CONCLUSIONS
  We conclude that CvV-BW1 composes a distinct species within C. variabilis virus.
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Noji Higashi 1-1-1, Kusatsu 525-8577, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Hoshina
authors.forename: Mayumi
authors.initials: M
authors.lastname: Shimizu
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Makino
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Haruyama
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Ueda
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kato
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kasahara
authors.forename: Bun-ichiro
authors.initials: B
authors.lastname: Ono
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Imamura
mesh_terms: D000818:Animals; D002708:Chlorella / Q000302:isolation & purification / Q000821:virology*; D004267:DNA Viruses / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D004279:DNA, Viral / Q000235:genetics / Q000302:isolation & purification; D004259:DNA-Directed DNA Polymerase / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D056145:Freshwater Biology; D007564:Japan; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D010247:Paramecium / Q000382:microbiology*; D010802:Phylogeny; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000235:genetics; D014771:Virion / Q000648:ultrastructure
chemical_list: D004279:DNA, Viral; D014764:Viral Proteins; D004259:DNA-Directed DNA Polymerase