title: Estrogen modulates hepatic gene expression and survival of rainbow trout infected with pathogenic bacteria Yersinia ruckeri.
abstract: In the aquatic environment, fish are exposed to various stimuli at once and have developed different response mechanisms to deal with these multiple stimuli. The current study assessed the combined impacts of estrogens and bacterial infection on the physiological status of fish. Juvenile rainbow trout were exposed to two different concentrations of 17β-estradiol (E2) (2 or 20 mg/kg feed) and then infected with three concentrations of Yersinia ruckeri, a bacterial pathogen causing massive losses in wild and farmed salmonid populations. Organism-level endpoints to assess the impact of the single and combined treatments included hepatic vitellogenin transcript expression to evaluate the E2 exposure efficiency and survival rate of pathogen-challenged fish. The two E2 doses increased vitellogenin levels within the physiological range. Infection with Y. ruckeri caused mortality of trout, and this effect was significantly enhanced by a simultaneous exposure to high E2 dose. The hormone reduced survival at intermediate and high (10(4) and 10(6) colony forming units, cfu) bacterial concentrations, but not for a low one (10(2) cfu). Analysis of hepatic gene expression profiles by a salmonid 2 k cDNA microarray chip revealed complex regulations of pathways involved in immune responses, stress responses, and detoxicification pathways. E2 markedly reduced the expression of several genes implicated in xenobiotic metabolism. The results suggest that the interaction between pathogen and E2 interfered with the fish's capability of clearing toxic compounds. The findings of the current study add to our understanding of multiple exposure responses in fish.
authors: Neuro-Endocrine Immune Interactions Research Group, Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, Zurich, Switzerland. michael.wenger@uzh.ch
authors: Michael
authors: M
authors: Wenger
authors: Aleksei
authors: A
authors: Krasnov
authors: Stanko
authors: S
authors: Skugor
authors: Elinor
authors: E
authors: Goldschmidt-Clermont
authors: Ursula
authors: U
authors: Sattler
authors: Sergey
authors: S
authors: Afanasyev
authors: Helmut
authors: H
authors: Segner
mesh_terms: D000818:Animals; D015169:Colony Count, Microbial / Q000662:veterinary; D017931:DNA Primers / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D005393:Fish Diseases / Q000188:drug therapy* / Q000382:microbiology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D046228:Microarray Analysis / Q000662:veterinary; D017686:Oncorhynchus mykiss; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016019:Survival Analysis; D014819:Vitellogenins / Q000378:metabolism; D015009:Yersinia Infections / Q000188:drug therapy / Q000662:veterinary*; D044124:Yersinia ruckeri
chemical_list: D017931:DNA Primers; D014819:Vitellogenins; D004958:Estradiol