title: Biochemical Mechanisms for Geographical Adaptations to Novel Toxin Exposures in Butterflyfish.
abstract: Some species of butterflyfish have had preyed upon corals for millions of years, yet the mechanism of butterflyfish specialized coral feeding strategy remains poorly understood. Certain butterflyfish have the ability to feed on allelochemically rich soft corals, e.g. Sinularia maxima. Cytochrome P450 (CYP) is the predominant enzyme system responsible for the detoxification of dietary allelochemicals. CYP2-like and CYP3A-like content have been associated with butterflyfish that preferentially consumes allelochemically rich soft corals. To investigate the role of butterflyfish CYP2 and CYP3A enzymes in dietary preference, we conducted oral feeding experiments using homogenates of S. maxima and a toxin isolated from the coral in four species of butterflyfish with different feeding strategies. After oral exposure to the S. maxima toxin 5-episinulaptolide (5ESL), which is not normally encountered in the Hawaiian butterflyfish diet, an endemic specialist, Chaetodon multicinctus experienced 100% mortality compared to a generalist, Chaetodon auriga, which had significantly more (3-6 fold higher) CYP3A-like basal content and catalytic activity. The specialist, Chaetodon unimaculatus, which preferentially feed on S. maxima in Guam, but not in Hawaii, had 100% survival, a significant induction of 8-12 fold CYP3A-like content, and an increased ability (2-fold) to metabolize 5ESL over other species. Computer modeling data of CYP3A4 with 5ESL were consistent with microsomal transformation of 5ESL to a C15-16 epoxide from livers of C. unimaculatus. Epoxide formation correlated with CYP3A-like content, catalytic activity, induction, and NADPH-dependent metabolism of 5ESL. These results suggest a potentially important role for the CYP3A family in butterflyfish-coral diet selection through allelochemical detoxification.
authors.affiliation: Department of Environmental Science, University of California Riverside, Riverside, California, United States of America.
authors.forename: Aileen
authors.identifier: 0000-0002-4359-3497
authors.initials: A
authors.lastname: Maldonado
authors.affiliation: Department of Environmental Science, University of California Riverside, Riverside, California, United States of America.
authors.forename: Ramon
authors.initials: R
authors.lastname: Lavado
authors.affiliation: University of Hawaii at Manoa, Honolulu, Hawaii, United States of America.
authors.forename: Sean
authors.initials: S
authors.lastname: Knuston
authors.affiliation: Department of BioMolecular Sciences and the National Center for Natural Products Research, University of Mississippi, University, Mississippi, United States of America.
authors.forename: Marc
authors.initials: M
authors.lastname: Slattery
authors.affiliation: Department of BioMolecular Sciences and the National Center for Natural Products Research, University of Mississippi, University, Mississippi, United States of America.
authors.forename: Sridevi
authors.initials: S
authors.lastname: Ankisetty
authors.affiliation: Woods Hole Oceanographic Institute, Woods Hole, Massachusetts, United States of America.
authors.forename: Jared V
authors.initials: JV
authors.lastname: Goldstone
authors.affiliation: Graduate School of Public Health, San Diego State University, San Diego, California, United States of America.
authors.forename: Kayo
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Graduate School of Public Health, San Diego State University, San Diego, California, United States of America.
authors.forename: Eunha
authors.initials: E
authors.lastname: Hoh
authors.affiliation: Department of BioMolecular Sciences and the National Center for Natural Products Research, University of Mississippi, University, Mississippi, United States of America.
authors.forename: Rama S
authors.initials: RS
authors.lastname: Gadepalli
authors.affiliation: Department of BioMolecular Sciences and the National Center for Natural Products Research, University of Mississippi, University, Mississippi, United States of America.
authors.forename: John M
authors.initials: JM
authors.lastname: Rimoldi
authors.affiliation: University of Hawaii at Manoa, Honolulu, Hawaii, United States of America.
authors.forename: Gary K
authors.initials: GK
authors.lastname: Ostrander
authors.affiliation: Department of Environmental Science, University of California Riverside, Riverside, California, United States of America.
authors.forename: Daniel
authors.initials: D
authors.lastname: Schlenk
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D000818:Animals; D037421:Anthozoa / Q000378:metabolism*; D001711:Biotransformation / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004224:Diterpenes / Q000378:metabolism / Q000633:toxicity*; D004781:Environmental Exposure / Q000009:adverse effects*; D004852:Epoxy Compounds / Q000378:metabolism; D005843:Geography; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D010473:Perciformes / Q000378:metabolism / Q000502:physiology*; D016019:Survival Analysis; D014118:Toxins, Biological / Q000378:metabolism / Q000633:toxicity*
chemical_list: C520059:5-episinuleptolide; D004224:Diterpenes; D004852:Epoxy Compounds; D014118:Toxins, Biological; D003577:Cytochrome P-450 Enzyme System