title: Notothenioid fish, krill and phytoplankton from Antarctica contain a vitamin E constituent (alpha-tocomonoenol) functionally associated with cold-water adaptation.
abstract: The vitamin E (VE) content of tissues from the Antarctic notothenioid fish, Chaenocephalus aceratus, Champsocephalus gunnari and Gobionotothen gibberifrons, and extracts of Antarctic krill Euphausia superba and phytoplankton collected from the Antarctic Peninsula was examined. Included in the VE composition was a newly described 'marine-derived' tocopherol (MDT), an unsaturated-isoprenoid derivative of alpha-tocopherol, that is attributed to enhancing antioxidant protection of cellular lipids at low temperature. MDT was found to co-exist with alpha-tocopherol in all Antarctic samples, ranging from 2.8 to 22.3% of the total VE composition. The highest level of VE was found in the liver of G. gibberifrons (VE=416.7 pmol/mg wet tissue) although this tissue had a low MDT composition (7.7%), whereas the greatest MDT composition was measured in the liver of C. gunnari (MDT=22.3%). In notothenioids, the pectoral adductor muscle, which has a high density of mitochondria, contained higher levels of VE than white myotomal muscle, but differences in MDT composition were small. Phytoplankton and krill also contained MDT, which supports the contention that MDT is obtained directly from the primary food chain. Our finding of MDT in Antarctic organisms is consistent with its putatively adaptive function to enhance antioxidant protection in coldwater metabolism.
authors.affiliation: Australian Institute of Marine Science, PMB No 3, Townsville MC, Queensland 4810, Australia. w.dunlap@aims.gov.au
authors.forename: Walter C
authors.initials: WC
authors.lastname: Dunlap
authors.forename: Akio
authors.initials: A
authors.lastname: Fujisawa
authors.forename: Yorihiro
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Moylan
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Sidell
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D000864:Antarctic Regions; D002851:Chromatography, High Pressure Liquid; D003080:Cold Temperature; D033201:Euphausiacea / Q000737:chemistry / Q000502:physiology*; D005399:Fishes / Q000502:physiology*; D015394:Molecular Structure; D010839:Phytoplankton / Q000737:chemistry / Q000502:physiology*; D012623:Seawater; D013329:Structure-Activity Relationship; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism*
chemical_list: C404388:alpha-tocomonoenol; D014810:Vitamin E