title: Adaptive response to environmental changes in the fish pathogen Moritella viscosa.
abstract: The marine psychrophilic bacterium Moritella viscosa is the causative agent of winter ulcer in farmed Atlantic salmon and cod. In this study, the growth requirements of the pathogen were established. The effects of changes in salinity and temperature on growth, surface features and proteomic regulation were also investigated. The genome of this bacterium has not yet been sequenced; therefore, comparative two-dimensional gel electrophoresis (2-DE) was used, coupled with high performance tandem mass spectrometry (MS/MS), to perform cross-species protein identification. Results from this study establish that M. viscosa is a true marine psychrophilic bacterium capable of surviving and proliferating in an oligotrophic and cold environment. Low temperature combined with 3-4% NaCl resulted in significantly higher cell yields and stability compared to high temperature and 1% NaCl. Nine cytoplasmic proteins were shown to be regulated by temperature and 12 by salinity. Several of the regulated proteins indicated a stressful situation at 15 degrees C compared to 4 degrees C, consistent with the growth characteristics observed. Furthermore, temperature and salinity were demonstrated to be important determinants of motility and viscosity of M. viscosa.
authors.affiliation: Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, Post Box 8146, 0033 Oslo, Norway. hege.smith.tunsjo@veths.no
authors.forename: Hege Smith
authors.initials: HS
authors.lastname: Tunsjø
authors.forename: Steinar Martin
authors.initials: SM
authors.lastname: Paulsen
authors.forename: Helene
authors.initials: H
authors.lastname: Mikkelsen
authors.forename: Trine Marie
authors.initials: TM
authors.lastname: L'abée-Lund
authors.forename: Eystein
authors.initials: E
authors.lastname: Skjerve
authors.forename: Henning
authors.initials: H
authors.lastname: Sørum
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis; D015180:Electrophoresis, Gel, Two-Dimensional; D005393:Fish Diseases / Q000382:microbiology; D034221:Moritella / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D009711:Nucleotides / Q000378:metabolism; D020317:Salmo salar / Q000382:microbiology*; D012965:Sodium Chloride / Q000494:pharmacology; D053719:Tandem Mass Spectrometry; D013696:Temperature
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D009711:Nucleotides; D012965:Sodium Chloride