Electrophoretic studies on blood proteins in an ecological series of isopod and amphipod species

An electrophoretic study of whole blood samples revealed the presence of haemocyanin and of various other proteins in the blood of fifteen species of marine and terrestrial amphipods and isopods. The amount of haemocyanin per 1 mm3 of blood is independent of body weight over a range from 10 mg to 1 kg. Under laboratory conditions and during starvation the haemocyanin level of the blood is lowered as compared with freshly caught specimens. No relationship between moulting stage and haemocyanin content could be established in three oniscoid isopods, representing Ligia, Oniscus, and Porcellio. In some species the densities of both haemocyanin and ‘slow proteins’ (i.e. proteins between starting line and haemocyanin) seem to vary in more or less the same direction, over at least part of the total range of variability. In the offshore Conilera, however, an indirect relationship seems to exist between these two protein fractions. This is reminiscent of the situation in Maia squinado described by Zuckerkandl (1960). The slow protein fractions appear to play a number of roles in the species investigated. In Conilera they consist of various copper proteids (perhaps concerned with the synthesis of haemocyanin?), while in intertidal amphipods and some isopods they carry chromophilic groups that may be of importance in mechanisms of colour change. The colour of the blood of a given specimen of Orchestia gammarella and Marinogammarus marinus depends on the amount of the faster moving, blue chromoproteid present in the blood. These chromoproteids are considered to be carotenoproteids.