title: Engineered Salmonella allows real-time heterologous gene expression monitoring within infected zebrafish embryos.
abstract: Microbial host-pathogen interactions have been traditionally well studied at genetic and physiological levels, but cell-resolution analyses have been particularly scarce. This has been especially remarkable for intracellular parasites for two major reasons: first, the inherent loss of bacteria traceability once infects its hosts; second and more important, the limited availability of genetic tools that allow a tight regulated expression of bacterial virulence genes once inside the host tissues. Here we present novel data supporting the use of zebrafish embryos to monitor Salmonella enterica serovar Thyphimurium infection. Intravenous infection of Salmonella can be easily monitored using in vivo fluorescence that allows the visualization of free-swimming bacteria through the circulatory system. Moreover, we have engineered Salmonella to voluntarily activate heterologous gene expression at any point during infection once inside the zebrafish macrophages using a salicylate-based expression system. This approach allows real-time cell-resolution in vivo monitoring of the infection. All together, this approach paves the road to cell-based resolution experiments that would be harder to mimic in other vertebrate infection models.
authors.affiliation: Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/Consejo Superior de Investigaciones Científicas/Junta de Andalucía, Ctra. Utrera, Km 1. 41013-Sevilla, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Medina
authors.forename: Eduardo
authors.initials: E
authors.lastname: Santero
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Gómez-Skarmeta
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Royo
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism*; D003199:Computer Systems; D003224:Congo Red; D004625:Embryo, Nonmammalian / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000502:physiology*; D005818:Genetic Engineering / Q000379:methods; D054884:Host-Pathogen Interactions / Q000502:physiology*; D008264:Macrophages / Q000378:metabolism; D008856:Microscopy, Fluorescence; D012459:Salicylates / Q000494:pharmacology; D012480:Salmonella Infections / Q000175:diagnosis* / Q000382:microbiology / Q000503:physiopathology*; D012486:Salmonella typhimurium / Q000235:genetics*; D015027:Zebrafish / Q000196:embryology*
chemical_list: D001426:Bacterial Proteins; D012459:Salicylates; D003224:Congo Red