• Molecular & Cellular Toxicology
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• v.5 no.2
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• pp.120-125
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• 2009

Alaria esculenta is a brown seaweed found in the Arctic. This study investigated the protective effect of A. esculenta extract (AEE) against oxidant-mediated injury and its mode of action in RAW264.7 macrophages. The methyl thiazolyl tetrazolium (MTT) assay showed that $H_2O_2$ treatment reduced cell viability, whereas AEE protected cells from $H_2O_2$-mediated cytotoxicity in a dose-dependent manner. Because heme oxygenase-1 (HO-1) is known to protect cells against oxidative damage, we investigated the effect of AEE on HO-1 gene expression and HO enzyme activity. The protective effect of AEE against $H_2O_2$-induced injury was correlated with increased HO enzyme activity. AEE also induced HO-1 mRNA and protein expression, as determined RT-PCR and Western blotting, respectively. To characterize the mechanisms by which AEE induces HO-1 gene expression, we examined the effect of AEE on the nuclear translocation of NF-E2-related factor-2 (Nrf2) and Akt phosphorylation. AEE treatment activated upstream signaling for HO-1 gene expression, including the nuclear translocation of Nrf2 and Akt phosphorylation. Collectively, these results suggest that AEE has anti-oxidant activity that is mediated, at least in part, via the activation of Nrf2 and Akt and the subsequent induction of HO-1 gene expression.

• Ocean and Polar Research
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• v.26 no.2
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• pp.121-132
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• 2004

Concentrations of Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn were determined in four arctic brown algae (Laminaria saccharina, L. digitata, Alaria esculenta, Desmarestia aculeata) in an attempt to examine for their metal accumulation capacity and also to assess their contamination levels. Macroalgae were collected from shallow subtidal waters (<20m) of Kongsfjorden (Kings Bay) on Spitsbergen during the period of the late July to early August 2003. Metal concentrations highly varied between sampling sites, species and tissue parts. Input of melt-water laden with terrigenous sediment particles seemed to have a large influence on baseline accumulations of some metals (Al, Fe, Mn, Pb etc.) in the macroalgae, causing a significant spatial variation. There were also significant concentration differences between the young and old tissue parts in L. saccharina, L. digitata and A. esculenta. While Al, Fe, Mn, Pb were higher in the perennial parts (stipes and holdfast below meristematic region), Cd and As concentrations were significantly higher in the young blades above the meristematic region. Zn and Cr, on the other hand, showed little differences between the tissue parts. The highest metal concentrations were found in D. aculeata, which seems to be due to its filamentous fine branches leading to high surface/volume ratios. The lowest concentrations were found in the two Laminaria spp., the blades of which are thicker than D. aculeata and A. esculenta. No distinct signs of contamination were detected in the brown algal species analyzed. Added to this, the results of the present studies suggest the potential utility of L. saccharina, L. digitata and A. esculenta as biomonitors for metal pollution monitoring in this area.

• Journal of Environmental Science International
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• v.13 no.9
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• pp.819-826
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• 2004

In order to elucidate the polycyclic aromatic hydrocarbon concentration and its origin in arctic area, four arctic brown algae (Laminaria saccharina, L. digita, Alaria esculenta, Desmarestia aculeata), one marine invertebrate (Echinoidea) and sediments were collected from Kongsfjorden in Spitsbergen from the late July to early August, 2003. In case of macroalgae, the young blade part above growth point and the old stipes and blades beneath growth point were separated and analyzed for polycyclic aromatic hydrocarbons (PAHs) in an attempt to check the mechanism of uptake in macroalgae to accumulate PAH. There was no difference in PAH concentrations between sampling sites (Stations B and C), species, and blades beneath and above growth point. PAH concentrations in all samples collected in this study were relatively higher than those reported in other areas of arctic. Especially, station C, which is known as an unpolluted area, showed 10 times higher PAH concentration (8,765 ng/g) in sediment than station A (694 ng/g) around harbor. In addition high PAH concentration, station C had very higher proportion of methylated PAH to parent PAH in sediment than station A. Source analysis using PAH isomer pair ratios as indicators showed that Kongsfjorden area seemed to be relatively contaminated with PAH derived from direct petroleum input.