Response
of fish membranes to environmental temperature
T. Farkas, E. Fodor, K. Kitajka, J.E. Halver-2001
Aquaculture
Research, 32(8): 645-655
Abstract:
The effect of temperature on fluidity, fatty acid and
molecular species composition of liver and brain phospholipids in fish
adapted or exposed to extreme temperatures was investigated. Membranes from
cold-adapted fish were more fluid than those from warm-adapted fish. Ability
to control membrane fluidity according to temperature appears in early
ontogenesis and is first evident in swim-up fry of carp. Red blood cells as
well as neurons of adult carp can continuously adjust the fluidity of their
external membranes to changing temperatures. Segregation of choline and
ethanolamine phosphoglycerides from livers of fish adapted to a cold/warm
environment showed an accumulation of molecular species containing a
monoenic fatty acid in position sn-1 and a polyenic fatty acid in position
sn-2 of the molecule in cold conditions. Model experiments using mixtures of
synthetic 18:1/22:6 phoshatidylethanolamines and 16:0/18:1
phosphatidylcholines demonstrated the involvement of these molecular species
in rendering the membranes less packed (more fluid) during adaptation to
reduced temperatures.
(Institute of Biochemistry, Biological Research
Centre, Hungarian Academy of Sciences, H-6701, Szeged, Hungary, e-mail: epa@nucleus.szbk.u-szeged.hu)