title: Viruses, virophages, and their living nature.
abstract: Over 100 years viruses have fascinated scientists around the world. Although biologists, chemists, physicians, veterinarians, and even physicists attempted to elucidate the nature of viruses, the question still remains "Are viruses alive?" Different theories have aimed at unifying our views of virology to provide an answer. However, the discovery of a mimivirus, its genome organization and replication cycle, in addition to the recently found virophage challenged the established frontier between viruses and parasitic cellular organisms. Consequently, the old controversy whether viruses are inert agents at the threshold of life or a different form of life was reignited. This review reopens the debate about the living nature of viruses from the classical concepts to the recent discoveries in order to rationally discuss our beliefs about the living or non-living character of viruses.
  
  
  BACKGROUND
  filterable agent; mimivirus; virophage.
authors.affiliation: Grupo de Microbiología y Epidemiología, Facultad de Medicina Veterinaria y de Zootecnia, Universidad Nacional de Colombia, Sede Bogotá, Carrera 30 No. 45-03 Edificio 561B, Colombia. julianruizsaenz@gmail.com
authors.forename: J
authors.initials: J
authors.lastname: Ruiz-Saenz
authors.forename: J D
authors.initials: JD
authors.lastname: Rodas
mesh_terms: D016679:Genome, Viral; D049672:History, 19th Century; D049673:History, 20th Century; D049674:History, 21st Century; D056686:Mimiviridae / Q000235:genetics; D014773:Virology / Q000266:history; D018406:Virus Physiological Phenomena; D014780:Viruses / Q000235:genetics / Q000472:pathogenicity