title: Rescue of fish exposed to a lethal dose of pathogen, by signals from sublethally exposed survivors.
abstract: Rainbow trout (Oncorhynchus mykiss, Walbaum) were challenged intraperitoneally with a sublethal dose of Vibrio anguillarum VIB1 and allowed to recover. Then, after 7 days, naïve fish, (designated as 'bystander' fish) which had never been exposed to the pathogen, were introduced to the same tank. These swam with the adapted (recovered) fish for 7 days before both groups and a control (never exposed directly to the pathogen or to recovered fish) group were exposed to a lethal dose of VIB1. Mortality records were 100% in the control group within 3 days, 47% in the adapted group and 60% in the unchallenged bystander group, which swam with the adapted group. In both the latter groups, the time to death of the non-surviving fish was attenuated. This inter-animal communication of signals has previously been documented for animals exposed to ionizing radiation. Assays of tissues from control, challenged and 'bystander fish exposed to the pathogen showed that a signal as yet unidentified but similar to that seen in bystanders to irradiated fish was being produced. This signal caused a sharp and transient increase in intracellular calcium and a decrease in clonogenicity in a well-characterized reporter assay.
authors.affiliation: Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada mothers@univmail.cis.mcmaster.ca.
authors.forename: Carmel
authors.initials: C
authors.lastname: Mothersill
authors.affiliation: School of Life Sciences, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK.
authors.forename: Dawn
authors.initials: D
authors.lastname: Austin
authors.affiliation: Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada.
authors.forename: Cristian
authors.initials: C
authors.lastname: Fernandez-Palomo
authors.affiliation: Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada.
authors.forename: Colin
authors.initials: C
authors.lastname: Seymour
authors.affiliation: Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling FK9 4LA UK.
authors.forename: Niall
authors.initials: N
authors.lastname: Auchinachie
authors.affiliation: Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling FK9 4LA UK.
authors.forename: Brian
authors.initials: B
authors.lastname: Austin
mesh_terms: D000222:Adaptation, Physiological; D000819:Animal Communication; D000818:Animals; D024201:Bystander Effect / Q000502:physiology; D020013:Calcium Signaling; D002478:Cells, Cultured; D005393:Fish Diseases / Q000382:microbiology*; D017686:Oncorhynchus mykiss / Q000382:microbiology*; D011839:Radiation, Ionizing; D014733:Vibrio / Q000472:pathogenicity*; D014735:Vibrio Infections / Q000382:microbiology / Q000662:veterinary*
keywords: Vibrio anguillarum; bystander effect; disease; rainbow trout; sublethal exposure