title: Vibrio cholerae typing phage N4: genome sequence and its relatedness to T7 viral supergroup.
abstract: OBJECTIVE
  In countries where cholera is endemic, Vibrio cholerae O1 bacteriophages have been detected in sewage water. These have been used to serve not only as strain markers, but also for the typing of V. cholerae strains. Vibriophage N4 (ATCC 51352-B1) occupies a unique position in the new phage-typing scheme and can infect a larger number of V. cholerae O1 biotype El Tor strains. Here we characterized the complete genome sequence of this typing vibriophage.
  
  
  METHODS
  The complete DNA sequence of the N4 genome was determined by using a shotgun sequencing approach.
  
  
  RESULTS
  Complete genome sequence explored that phage N4 is comprised of one circular, double-stranded chromosome of 38,497 bp with an overall GC content of 42.8%. A total of 47 open reading frames were identified and functions could be assigned to 30 of them. Further, a close relationship with another vibriophage, VP4, and the enterobacteriophage T7 could be established. DNA-DNA hybridization among V. cholerae O1 and O139 phages revealed homology among O1 vibriophages at their genomic level.
  
  
  CONCLUSIONS
  This study indicates two evolutionary distinctive branches of the possible phylogenetic origin of O1 and O139 vibriophages and provides an unveiled collection of information on viral gene products of typing vibriophages.
authors: Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India.
authors: Mayukh
authors: M
authors: Das
authors: R K
authors: RK
authors: Nandy
authors: Tushar Suvra
authors: TS
authors: Bhowmick
authors: S
authors: S
authors: Yamasaki
authors: A
authors: A
authors: Ghosh
authors: G B
authors: GB
authors: Nair
authors: B L
authors: BL
authors: Sarkar
mesh_terms: D025522:Bacteriophage N4 / Q000235:genetics*; D001482:Base Composition; D016000:Cluster Analysis; D004279:DNA, Viral / Q000737:chemistry* / Q000235:genetics*; D016679:Genome, Viral; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D016366:Open Reading Frames; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D041241:Vibrio cholerae O1 / Q000821:virology*
chemical_list: D004279:DNA, Viral