New Zealand Journal of Marine and Freshwater Research abstracts
Strategies of anaerobiosis in New Zealand infaunal bivalves: adaptations to
environmental and functional hypoxia
JASON L. CARROLL
RUFUS M. G. WELLS*
School of Biological Sciences
The University of Auckland
Private Bag 92 019
Auckland, New Zealand
Abstract Under hypoxic environmental conditions, slowly burrowing
bivalves such as the pipi (
Paphies australis) and cockle (
Austrovenus
stutchburyi) support anaerobic energy production through the pyruvate
reductase enzymes strombine dehydrogenase and alanopine dehydrogenase. Rapidly
digging surf clams such as the tuatua (
P. subtriangulatum) and
trough shell (
Mactra discors) do not fare as well at low oxygen levels,
but perform better under the functional anaerobiosis generated by burrowing,
and energy production is supported by octopine dehydrogenase. Muscle buffering
capacity is higher in rapidly burrowing species and is correlated with total
pyruvate reductase activity. Anaerobic pathways in
P. subtriangulatum
led to both D-lactate and octopine accumulation during environmental hypoxia,
but only octopine accumulated during burrowing. Bivalves adapted to
environmental hypoxia maintained high adenylate energy charge (AEC) under
anaerobiosis, indicating a close matching of ATP production to consumption. AEC
fell in
P. subtriangulatum during environmental hypoxia. The
significance of these findings is discussed within an ecological context, and
in relation to the storage of live clams for the seafood industry.
Keywords bivalves; anaerobiosis; pyruvate reductase; buffering capacity;
energy charge; lactate; octopine
New Zealand Journal of Marine and Freshwater Research, 1995: Vol. 29:
137-146
0028-8330/95/2902-0137 $2.50/0 (c) The Royal Society of New Zealand
1995
PDF file of entire paper: medium quality (734K); (scanned from paper original: notes about this process)
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