Elevated levels of trimethylamine oxide in muscles of deep-sea gadiform teleosts: A high-pressure adaptation?
✍ Scribed by Gillett, Matthew B.; Suko, Jolyn R.; Santoso, Freddy O.; Yancey, Paul H.
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 73 KB
- Volume
- 279
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Trimethylamine oxide (TMAO) as an osmolyte typically occurs at 20-70 mM in shallow-water marine teleost fishes. However, it has not been previously examined in deep-living species. We collected species from two families of benthic gadiform teleosts by otter trawl from the continental slope (1,800-2,000 m) and abyssal plain (2,850 m) off the Oregon coast. Muscle and plasma samples were analyzed for TMAO with a picric acid method. Muscle contents (below in millimoles/kilogram of wet weight) were found to be higher than previously reported for teleosts. Results from Macrouridae from 1,800-2,200 m were as follows: Albatrossia pectoralis, 83 ± 10; Coryphaenoides cinerus, 121 ± 11. Results from Macrouridae from 2,850 m were significantly higher: C. leptolepis, 158 ± 20; C. fillifer, 177 ± 8; C. armatus, 173 ± 5. Caught at both depths, Antimora microlepis (Moridae) had 211 ± 14. Plasmas had low TMAO (2-15 mM) and high Na + concentra- tions (227-273 mM), except A. microlepis plasma, which had the lowest Na + (219 ± 30 mM) and highest TMAO (159 ± 46 mM). Osmotic pressures of fresh plasma (423-557 mosm) correlated highly with muscle TMAO and with plasma TMAO plus Na + levels. These higher osmolalities may reduce osmoregulatory costs. However, as a methylamine known to stabilize protein, TMAO may counteract destabilizing effects of hydrostatic pressure on cellular proteins. With purified C. leptolepis muscle lactate dehydrogenase, 250 mM TMAO fully offset a 30% increase in NADH Km induced by 300 atm.