The aim of this study was to evaluate the effects of chemically dispersed oil on an economically and ecologically important species inhabiting coasts and estuaries, the Pacific oyster Crassostrea gigas. Studies were carried out with juveniles, known to generally be more sensitive to environmental stress than adults. A set of enzyme activities involved in immune defence mechanisms and detoxifica...

Haemolymph from late third-instar larvae of the blowflies Calliphora sp. (Karlson & Schweiger, 1961 ; Thomson & Sin, 1970) and Lucilia cuprina (Hackman & Goldberg, 1967) contains phenol oxidase in an inactive or proenzyme form. The anterior end of a late third-instar Sarcophaga larva was pricked with a fine pin and the haemolymph released (approx. 5 0 ~ 1 ) was collected in an ice-cold tube. By...

Contaminant effects on defence responses of ecologically and economically important organisms, such as the Pacific oyster Crassostrea gigas, are likely to influence their ability to resist infectious diseases, particularly at the young stages. The aim of this study was to explore the potential relationships between organic contaminants accumulated in the soft tissues of juvenile oysters, defenc...

Phenoloxidases (POs) are a family of enzymes including tyrosinases, catecholases and laccases, which play an important role in immune defence mechanisms in various invertebrates. The aim of this study was to thoroughly identify the PO-like activity present in the hemolymph of the Pacific oyster Crassostrea gigas, by using different substrates (i.e. dopamine and p-phenylenediamine, PPD) and diff...

One Mn(II) coordination polymer, [Mn(o-(NO2)C6H4COO)2(pyz)(H2O)]n (1), has been synthesized and oxidized with n-Bu4NMnO4 in non-aqueous media to two mixed-valence hexanuclear Mn(II/III) complexes [MnIII2MnII4O2(pyz)0.61/(MeOH)0.39(o-(NO2)C6H4COO)10·(H2O)·{(CH3)2CO}2]·(CH3)2CO (2) and [MnIII2MnII4O2(pyz)0.28/(MeCN)3.72(o-(NO2)C6H4COO)10·(H2O)] (3) (where pyz = pyrazine). All three complexes were...

background: mushroom tyrosinase a potent candidate in clinical studies known as polyphenol oxidase, is a metaloenzyme from the oxidase superfamily widely distributed from lower to higher life forms. it plays a crucial role in sclerotization of exoskeleton in insects, also responsible for skin pigmentation in mammalians. objective: in this study, after reconstitution of mt by some metal ions, th...

as oxygenic photosynthetic organisms evolved. Organisms had to develop different strategies to handle a final product of photosynthesis, dioxygen (O2), as well as its highly reactive derivatives, superoxide anions, hydrogen peroxide and hydroxyl radicals. Several enzymes, such as superoxide dismutase, catalase and peroxidase, evolved that protected the organisms. A particular class of protein, ...