Hemibastadin derivatives, including the synthetically-derived 5,5'-dibromohemibastadin-1 (DBHB), are potent inhibitors of blue mussel phenoloxidase (PO), which is a key enzyme involved in the firm attachment of this invertebrate to substrates and, thus, a promising molecular target for anti-fouling research. For a systematic investigation of the enzyme inhibitory activity of hemibastadin deriva...

Phenoloxidase from Artemia sinica (AsPO) was purified by Superdex 200 gel-filtration and Q Sepharose fast flow ion-exchange chromatography, and its properties were characterized biochemically and enzymatically by using L-dihydroxyphenylalanine (L-DOPA) as the specific substrate. Results showed that AsPO was isolated as a monomeric protein of 125.5 kDa in molecular mass. The optimal pH value and...

In insects the enzyme phenoloxidase (PO) catalyzes melanin deposition at the wound site and around parasitoid eggs. Its proenzyme prophenoloxidase (proPO) is proteolytically cleaved to active phenoloxidase by a cascade consisting of serine proteases and inhibited by serpins. The Drosophila genome encodes 29 serpins, of which only two, Serpin-27A (Spn27A) and Necrotic, have been analyzed in deta...

The total haemocyte count (THC), differential haemocyte count (DHC), phenoloxidase activity, respiratory burst (release of superoxide anion), superoxide dismutase activity, phagocytic activity and clearance efficiency to the pathogen Vibrio alginolyticus were measured when the white shrimp Litopenaeus vannamei (9.4-11.3 g) were injected individually with sodium alginate at 10, 20 or 50 microg g...

Organic and inorganic contaminants can suppress immune function in molluscs and crustaceans. It was postulated that metals could modulate immune function in marine crabs. To test this hypothesis, sublethal effects of mercury (Hg) on cellular immune and biochemical responses of crabs were determined. When crabs were exposed for 14 d to environmentally-relevant concentrations of Hg, changes in im...

The prophenoloxidase (ProPO) system is the origin of melanin production and is considered to be an innate defence mechanism in invertebrates. In different bivalve species, phenoloxidase (PO) is present in the haemolymph as an inactive form of ProPO. The present study focuses on the Pacific adult oyster, Crassostrea gigas, an economically important bivalve species along French coasts. The result...

The QM, firstly identified as a putative tumor suppressor gene from human, has been confirmed to possess varieties of functions in a range of organisms. In the present study, the cDNA that encodes a 220-amino-acid QM protein with calculated molecular mass of 25.5 kDa and isoelectric point of 10.07 was characterized from the Pacific white shrimp Litopenaeus vannamei. Analysis of the deduced amin...

Taiwan abalones, Haliotis diversicolor supertexta, held in 30 parts/per thousand seawater at 28 degrees C, were injected with TSB-grown Vibrio parahaemolyticus (1.6x10(5) cfu abalone(-1)) and then transferred to 20, 24, 28 and 32 degrees C. All abalones transferred to 32 degrees C died by 72 h. The mortality of V. parahaemolyticus-injected abalone held at 20 and 24 degrees C was significantly l...

Although it has been previously found by most authors that only plasmatocytes are involved in phagocytosis of non-self in the greater wax moth, Galleria mellonella, in the present study we demonstrate that in vitro, both granular cells and plasmatocytes are involved in this reaction, using monolayers of these haemocytes prepared from larval haemolymph by a differential cell fractionation method...

Explanations for the evolution of pathogen-induced fecundity reduction usually rely on a common principle: the trade-off between host longevity and reproduction. Recent advances in nutritional research have, however, challenged this assumption and shown that longevity and reproduction are not inextricably linked. In this study, we showed that beetles infected by cysticercoids of the tapeworm Hy...