Effects of Leucine-enkephalin on Catalase Activity and Glutathione Level in Haemolymph of the Scallop Chlamys farreri

Effect of four different vegetable oils (red palm olein, palm olein, corn oil, coconut oil) on antioxidant enzymes activity of rat liver

The objective of the study was to evaluate the effect of four different vegetable oils [red palm olein (RPO), palm olein (PO), corn oil (CO), coconut oil (COC)] on antioxidant enzymes activity of rat liver. Sixty six Sprague Dawley male rats which were randomly divided into eleven groups of 6 rats per group and were treated with 15% of RPO, PO, CO and COC for 4 and 8 weeks. Rats in the control group were given normal rat pellet only while in treated groups, 15% of additional different vegetable oils were given. After 4 weeks of treatment the catalase (CAT) activity results showed that there was no significance difference (p > or = 0.05) between the control group and treated groups while after 8 weeks of treatment showed that there was no significant different (p > or = 0.05) between control group and RPO group but the treated rat liver with PO, CO and COC groups were the lowest and it were significantly lower (> or = 0.05) than control group. For superoxide dismutase (SOD) there was no significance difference (p > or = 0.05) between the control group and treated groups of vegetable oils after 4 and 8 weeks of treatment. Thus the study indicated that there was no significant (p > or = 0.05) effect on antioxidant enzyme (superoxide dismutase) but there was significant effect (p > or = 0.05) on catalase in rat liver.

Effects of the model PAH phenanthrene on immune function and oxidative stress in the haemolymph of the temperate scallop Pecten maximus

Phenanthrene, a major component of crude oil, is one of the most abundant PAHs in aquatic ecosystems, and is readily bioavailable and toxic to a range of marine invertebrates. Within bivalves, the haemolymph acts as a transfer medium for these pollutants and their metabolic products, leaving haemocytes susceptible to deleterious effects. Using a suite of biological endpoints, this study determined the sublethal (7-d exposure to 50, 100 and 200microgL(-1)) effects of phenanthrene on several oxidative stress and immunological parameters in the haemolymph of the commercially-important scallop Pecten maximus. Phenanthrene exposure (200microgL(-1)) resulted in immune modulation with significant reductions in cell membrane stability (P<0.05) and phagocytosis (P<0.05), and a significant increase in the number of total haemocytes (P<0.05). Oxidative stress was also observed with a significant decrease in total glutathione (P<0.05) and significantly increased levels of lipid peroxidation in the haemolymph (P<0.05). Changes in the cellular and biochemical endpoints observed in this study illustrate their potential use in assessing the subtle effects of contaminant exposure. Whilst previous reports have suggested a link between free radical generation and immune suppression in vertebrates, this is the first instance where oxidative stress and immune function have been measured together in the haemolymph of a bivalve mollusc, demonstrating a possible link between PAH-induced oxidative stress and the subsequent inhibition in haemocyte immune function.

Immunohistological detection of mu, delta and kappa opioid-like receptors in the gill, gonad, and hemocytes of the scallop Chlamys farreri

Endogenous opioid peptides and opioid receptors form a neuromodulatory system, which plays an important part in the control of physiological pathways. In addition, some opioid peptides can function as endogenous messengers of the immune system and participate in the regulation of the immune response. The present studies indicated that mu, delta, and kappa opioid-like receptors were present in the gill and gonad of the scallop Chlamys farreri. Furthermore, the significance of opioid peptides involvement with the immune system is ascertained from the presence of mu, delta, and kappa opioid-like receptors on hemocytes of the scallop. Our report constitutes the first characterization of mu, delta, and kappa opioid-like receptors in the gill and gonad of the scallop Chlamys farreri.

Effects of leucine-enkephalin on catalase activity and hydrogen peroxide levels in the haemolymph of the Pacific Oyster (Crassostrea gigas)

The nervous and immune systems of invertebrates can exchange information through neuropeptides. Furthermore, some opioid peptides can function as endogenous immune system messengers and participate in the regulation of the immune responses. The present study was designed to investigate the effects of leucine-enkephalin (L-ENK) on the activity of catalase (CAT) and hydrogen peroxide (H₂O₂) content in the haemolymph of the Pacific Oyster (Crassostrea gigas). The CAT activity and H₂O₂ content were investigated after the haemolymph of the species was exposed to 1, 5, and 50 μg/mL of L-ENK. The results indicate that the intracellular and extracellular CAT activity was increased with increasing concentration of L-ENK, while the intracellular and extracellular H₂O₂ content was decreased with increasing concentration of L-ENK. L-ENK may regulate the intracellular and extracellular CAT activity and H₂O₂ content via binding with opioid neuropeptide receptors on immunocytes of the oysters. The data strongly suggests an involvement of opioid peptides in the regulation of the antioxidant defence systems of Crassostrea gigas.