Gastroliths are transient extracellular calcium deposits formed by the crayfish Cherax quadricarinatus von Martens on both sides of the stomach wall during pre-molt. Gastroliths are made of a rigid chitinous organic matrix, constructed as sclerotized chitin-protein microfibrils within which calcium carbonate is deposited. Although gastroliths share many characteristics with the exoskeleton, the...

The native molecule of Rapana venosa hemocyanin (RvH) consists of two structural subunits RvH1 and RvH2 and each of them contains 8 functional units with different carbohydrate content. In this study, the antiviral effect of the native molecule of RvH and its isoforms against Epstein-Barr virus (EBV) is presented. This virus is the etiologic agent of acute form of the disease infectious mononuc...

Functional interpretations of the insect tracheal system – a branched series of tubes supplying oxygen from the environment to every metabolizing tissue in the insect’s body – are plagued by two related myths. The first is that gases move through the tracheal system entirely by diffusion. This idée fixe persists despite many studies showing that, across vast taxonomic distances, insects activel...

Hemocyanins are allosterically regulated oxygen carriers freely dissolved in the blood of many crustaceans. The natural modulator urate accumulates under hypoxic conditions in the hemolymph of Homarus vulgaris, and increases the oxygen affinity of the respiratory pigment. Other non-physiological effectors such as caffeine, dimethylxanthines and methylxanthines are also known to modulate the oxy...

The enzymatic activity of phenoloxidase is assayed routinely in the presence of SDS. Similar assay conditions elicit phenoloxidase activity in another type 3 copper protein, namely hemocyanin, which normally functions as an oxygen carrier. The nature of the conformational changes induced in type 3 copper proteins by the denaturant SDS is unknown. This comparative study demonstrates that arthrop...

Hemocyanins are large oligomeric respiratory proteins found in many arthropods and mollusks. The overall expression of hemocyanin mRNA, revealed by studies on Plecoptera hemocyanin sequencing, has raised the question of whether the protein is expressed or not. In fact, the presence of expressed hemocyanin has only been reported in the literature for one species, Perla marginata (Panzer, 1799). ...