Copper and haemocyanin dynamics in aquatic invertebrates

Abstract

Mechanisms of copper accumulation and detoxification, and of haemocyanin biosynthesis and catabolism, in aquatic arthropods and molluscs are reviewed. Crustacean haemocyanin transports copper in the blood by sequestering additional copper outside the oxygen-binding centre. Large changes in haemocyanin concentration in crustacean blood during moulting and hyposaline exposure generally reflect extracellular volume adjustments rather than biosynthesis and catabolism. Haemocyanin synthesis in decapod crustaceans is stimulated by hypoxia and, in an amphipod, by parasitization. Starvation causes breakdown of haemocyanin. Haemocyanin synthesis occurs principally in the midgut gland of crustaceans and in fixed blood cells (cyanocytes) that are located in certain tissues. It is hypothesized that cyanocytes provide a local oxygen reserve during circulatory arrest. Haemocyanin synthesis occurs primarily in the branchial glands of dibranchiate cephalopods but in the midgut gland of tetrabranchiates. Connective tissue pore cells are proposed as the site of haemocyanin synthesis in gastropods, although similar cells in cephalopod branchial hearts probably catabolize haemocyanin. Crustacean midgut glands contain copper-metallothioneins and glutathione, which donate Cu(I) to apohaemocyanin and function in detoxification and mineralization of excess copper. The physiological significance of high concentrations of quasi-crystalline haemocyanin within vascular spaces of the prosobranch left kidney, opisthobranch blood gland and cephalopod branchial heart appendage is discussed.

Transcriptomic responses of the endangered freshwater mussel Margaritifera margaritifera to trace metal contamination in the Dronne River, France

“…Cu is an essential micronutrient required by all living organisms, acting as a cofactor of many enzymes and a component in other proteins (Taylor and Anstiss 1999). The GO enrichment analysis revealed an over-representation of the GO molecular function Bcatalytic activity^(GO:0003824) in contigs linked to Cu (Table 6).…”

The Dart estuary, Devon, UK: a case study of chemical dynamics and pollutant mobility

“…Environmental stress can also induce the moult cycle of crabs, which may lead to changing partitioning of essential (Cu and Ca) and non-essential (Al and Pb) metals in the gill tissues to the exoskeleton (Taylor and Anstiss, 1999;Schuwerack, 2002). The moult cycle in C. maenas seems to be sex-specific in terms of timing for the Dart: the moults occur in May for the males and in June for the females (Ley, 2000).…”

“…This may well have affected the variability in trace Table 7. Ratios of trace elements to Fe in sediments of the lower Dart estuary and Eastern UK rivers as collected within the LOIS programme and related research (Neal and Robson, 2000;Neal and Davies, 2003 (Taylor and Anstiss, 1999). With increased metal concentrations in the water column, crystal deposits on the cuticle of the gill lamellae lead to decreased O 2 uptake and ion exchange and subsequent respiratory impairment and increased levels of haemocyanin and Cu in gill tissues in crabs.…”

“…Trace metal accumulation in the biota can often be highly variable from species to species and with diurnal and seasonal cycles (Bryan, 1979;Engel et al, 1981;Schuwerack, 2002). Metal uptake and accumulation may differ with the nutritional state, age, size and sex of the animal (Leung and Furness, 2000;Schuwerack, 2002), while metal fluctuations in crustaceans exhibit periodisms due to their moult cycle (Bryan, 1979;Engel and Brouwer, 1987;Taylor and Anstiss, 1999). Although the uptake of contaminants via food or water has been studied extensively in marine crustacean species (Eisler, 1987;Depledge and Rainbow, 1990), studies of bioaccumulation in UK estuaries must be advanced (Bryan and Langston, 1992;Matthiessen and Law, 2002) before serious environmental risks can be assessed and remediation strategies determined.…”

The molecular heterogeneity of hemocyanin: Its role in the adaptive plasticity of Crustacea

“…However, it represents one among several factors, such as allosteric regulation of the oxygenbinding properties, involved in the integrated physiology of oxygen transport adaptation. Thus, a marked difference exists between and within species as far as the direction and the magnitude of the observed concentration variation are concerned (Truchot, 1992;Taylor and Anstiss, 1999;Spicer and Baden, 2001;Baden et al, 2003).…”