ISSN:
1438-3888
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Variations in haemolymph protein composition and concentration, in copper content and copper distribution in the tissue of decapod crustaceans are reviewed. Haemocyanin is the major haemolymph constituent (〉 60%); the remaining proteins (in order of concentration) include coagulogen, apohaemocyanin, hormones and antisomes. Moulting, nutritional state, infection, hypoxia and salinity fluctuations are the major factors affecting the relative proportions and total quantities of the haemolymph proteins. With regard to haemocyanin, the changes in concentration during the moult cycle are principally associated with changes in haemolymph volume, rather than with changes in total haemocyanin content due to synthesis or catabolism. The role of the midgut gland in regulating haemolymph copper and haemocyanin concentration has been re-evaluated. More than 50% of the whole body copper load is stored in the haemolymph. In contrast, less than 3% of the copper load resides in the midgut gland. The latter has little potential for regulating haemolymph copper levels, at least in the short term (hours to a few days), though it may be involved in regulating haemocyanin levels over longer periods (weeks to months). The total copper content of the haemolymph remains within a narrow range, except during starvation when levels may decrease. Consequently, variations in the copper content of soft tissues, which constitute only 20% of decapod dry weight, do not significanlty alter whole body copper concentrations. Evidence that copper released following haemocyanin catabolism becomes bound to metallothionein for later use in the resynthesis of haemocyanin is reviewed and found to be inconclusive. The amount of copper that can be stored in this way is trivial compared with the amount of copper required to permit significant changes in haemolymph haemocyanin concentration. Average tissue copper requirements, calculated during the present study, are approx. 4 times higher than previous theoretical estimates.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02367900
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