Isolation and characterization of a virus (CvV-BW1) that infects symbiotic algae of Paramecium bursaria in Lake Biwa, Japan

Virol J. 2010 Sep 13:7:222. doi: 10.1186/1743-422X-7-222.

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.

MeSH terms

  • Animals
  • Chlorella / isolation & purification
  • Chlorella / virology*
  • DNA Viruses / classification*
  • DNA Viruses / genetics
  • DNA Viruses / isolation & purification*
  • DNA, Viral / genetics
  • DNA, Viral / isolation & purification
  • DNA-Directed DNA Polymerase / genetics
  • Electrophoresis, Gel, Pulsed-Field
  • Freshwater Biology
  • Japan
  • Microscopy, Electron, Transmission
  • Molecular Sequence Data
  • Paramecium / microbiology*
  • Phylogeny
  • Restriction Mapping
  • Sequence Analysis, DNA
  • Viral Plaque Assay
  • Viral Proteins / genetics
  • Virion / ultrastructure

Substances

  • DNA, Viral
  • Viral Proteins
  • DNA-Directed DNA Polymerase

Associated data

  • GENBANK/AB572585