Environmental induction of Na+ transporter affinity in Atlantic salmon embryos |
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Authors: | P. G. McWilliams |
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Affiliation: | Zoological Laboratory, University of Bergen, 5007 Bergen, Norway |
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Abstract: | Atlantic salmon ( Salmo salar L.) alevins hatched from eggs transferred from high- to low-Na water at 250° days, before the onset of the phase of increasing whole egg sodium content (at ∼380°days), showed a significantly reduced K m for Na+ transport, whereas transfer at 400° days did not produce any change in K m . Alevins hatched from eggs given acid shocks of 1, 3, 7 or 14 days duration initiated at 250 or 400° days showed no significant changes in Na+ transporter K m . Extended acid exposure (38 days) from 250°days to hatching resulted in a slight lowering of K m (P<0.05). A 24-day acid exposure from 400°days to hatching had no effect on Na+ transporter K m . Alevins hatched from eggs incubated throughout in acidified water had a significantly reduced K m compared to controls (P<0.01). The timing and duration of periods of Na depletion of eggs is considered with respect to environmental induction of increased Na transporter affinity in teleost embryos as a mechanism of long-term physiological adaptation to the gradual acidification of natural waters. |
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Keywords: | Salmo salar embryo alevin ion transporter sodium affinity sodium uptake adaptation acidification |
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