title: Genetic characterization of ØVC8 lytic phage for Vibrio cholerae O1.
abstract: BACKGROUND
  Epidemics and pandemics of cholera, a diarrheal disease, are attributed to Vibrio cholera serogroups O1 and O139. In recent years, specific lytic phages of V. cholera have been proposed to be important factors in the cyclic occurrence of cholera in endemic areas. However, the role and potential participation of lytic phages during long interepidemic periods of cholera in non-endemic regions have not yet been described. The purpose of this study was to isolate and characterize specific lytic phages of V. cholera O1 strains.
  
  
  METHODS
  Sixteen phages were isolated from wastewater samples collected at the Endhó Dam in Hidalgo State, Mexico, concentrated with PEG/NaCl, and purified by density gradient. The lytic activity of the purified phages was tested using different V. cholerae O1 and O139 strains. Phage morphology was visualized by transmission electron microscopy (TEM), and phage genome sequencing was performed using the Genome Analyzer IIx System. Genome assembly and bioinformatics analysis were performed using a set of high-throughput programs. Phage structural proteins were analyzed by mass spectrometry.
  
  
  RESULTS
  Sixteen phages with lytic and lysogenic activity were isolated; only phage ØVC8 showed specific lytic activity against V. cholerae O1 strains. TEM images of ØVC8 revealed a phage with a short tail and an isometric head. The ØVC8 genome comprises linear double-stranded DNA of 39,422 bp with 50.8 % G + C. Of the 48 annotated ORFs, 16 exhibit homology with sequences of known function and several conserved domains. Bioinformatics analysis showed multiple conserved domains, including an Ig domain, suggesting that ØVC8 might adhere to different mucus substrates such as the human intestinal epithelium. The results suggest that ØVC8 genome utilize the "single-stranded cohesive ends" packaging strategy of the lambda-like group. The two structural proteins sequenced and analyzed are proteins of known function.
  
  
  CONCLUSIONS
  ØVC8 is a lytic phage with specific activity against V. cholerae O1 strains and is grouped as a member of the VP2-like phage subfamily. The encoding of an Ig domain by ØVC8 makes this phage a good candidate for use in phage therapy and an alternative tool for monitoring V. cholerae populations.
authors.affiliation: Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional Autónoma de México, Circuito Escolar S/N, Ciudad Universitaria, Delegación Coyoacán, 04510, México, D.F, México.|Laboratorio de Patogenicidad Bacteriana, Unidad de Hemato-Oncología e Investigación, Hospital Infantil de México Federico Gómez/Facultad de Medicina, UNAM. Dr. Márquez No. 162, Col Doctores, Delegación Cuauhtémoc, 06720, México, D.F, México.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Solís-Sánchez
authors.affiliation: Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional Autónoma de México, Circuito Escolar S/N, Ciudad Universitaria, Delegación Coyoacán, 04510, México, D.F, México.|Laboratorio de Patogenicidad Bacteriana, Unidad de Hemato-Oncología e Investigación, Hospital Infantil de México Federico Gómez/Facultad de Medicina, UNAM. Dr. Márquez No. 162, Col Doctores, Delegación Cuauhtémoc, 06720, México, D.F, México.
authors.forename: Ulises
authors.initials: U
authors.lastname: Hernández-Chiñas
authors.affiliation: Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional Autónoma de México, Circuito Escolar S/N, Ciudad Universitaria, Delegación Coyoacán, 04510, México, D.F, México.
authors.forename: Armando
authors.initials: A
authors.lastname: Navarro-Ocaña
authors.affiliation: Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, 04510, México, D.F, México.
authors.forename: Javier
authors.initials: J
authors.lastname: De la Mora
authors.affiliation: Laboratorio de Investigación en Bacteriología Intestinal, Unidad de Hemato-Oncología e Investigación Hospital Infantil de México Federico Gómez, Dr. Márquez No. 162, Col. Doctores, Delegación Cuauhtémoc, 06720, México, D.F, México.
authors.forename: Juan
authors.initials: J
authors.lastname: Xicohtencatl-Cortes
authors.affiliation: Departamento de Salud Pública, Facultad de Medicina, Universidad Nacional Autónoma de México, Circuito Escolar S/N, Ciudad Universitaria, Delegación Coyoacán, 04510, México, D.F, México. carlos_01eslava@yahoo.com.mx.|Laboratorio de Patogenicidad Bacteriana, Unidad de Hemato-Oncología e Investigación, Hospital Infantil de México Federico Gómez/Facultad de Medicina, UNAM. Dr. Márquez No. 162, Col Doctores, Delegación Cuauhtémoc, 06720, México, D.F, México. carlos_01eslava@yahoo.com.mx.
authors.forename: Carlos
authors.initials: C
authors.lastname: Eslava-Campos
mesh_terms: D001433:Bacteriolysis; D001435:Bacteriophages / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology* / Q000648:ultrastructure; D002771:Cholera / Q000382:microbiology; D023061:Gene Order; D016679:Genome, Viral; D006801:Humans; D008800:Mexico; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D041241:Vibrio cholerae O1 / Q000821:virology*; D056189:Viral Tropism
keywords: Bacteriophage; Caudovirales; Podoviridae; Vibrio cholerae; ØVC8