Biological Evaluation of the Pollution of the Tsurumi River with 7-Ethoxycoumarin O-Deethylase Activity Induced by River Sediment Extracts in HepG2 Cells.

Abstract

The pollution level of the Tsurumi River flowing into Tokyo Bay was studied longitudinally using river sediment extracts in an assay system based on the arylhydrocarbon receptor (AhR)-dependent induction of 7-ethoxycoumarin O-deethylase (ECOD) activity in HepG2 cells. The sampling points of river sediment were as follows: Namamugi, Kami-Sueyoshi, Tsunashima, Shin-Yokohama A and B (downstream and upstream, respectively, from the former open-air industrial waste incineration site), Kozukue and Nakayama (Fig. 1). ECOD activity was induced to different extents in all samples tested. Namamugi, located in the middle of Keihin Industrial District, was considered to be the most polluted, followed by Shin-Yokohama A and Tsunashima. Results from these samples showed reverse U-shaped dose-response curves in terms of ECOD activity as well as 3-methylcholantrene (3-MC) although the expression of CYP1A1 mRNA in HepG2 cells remained roughly constant at higher concentrations as in the case of 3-MC, thus implying post-transcriptional suppression.

Seasonal and spatial distribution of trace elements in the water and sediments of the Tsurumi River in Japan

“…The inland manufacturing district is located in the river basin. Moreover, open-air industrial waste incineration has been performed on the river at Shin Yokohama area (Nito et al 2003). The Tsurumi river observatory data suggest that the average flow rate is higher in summer than that of winter.…”

Geochemical distribution of trace metal pollutants in water and sediments of downstream of an urban river

“…The inland manufacturing district is located in the river basin. Moreover, open -air industrial waste incineration has been performed on the river at Shin-Yokohama area (Nito et al, 2003). The area mainly consists of Tertiary and Quaternary sedimentary rocks (shale and sandstone) overlain by Quaternary volcanic materials and weathered soils of volcanic origin.…”

Possible Involvement of Chlorinated Ethylenes in Arylhydrocarbon Receptor-Related Induction of Cytochrome P4501A1 (CYP1A1) in Human Hepatoma HepG2 Cells

“…Ethoxycoumarin O-Deethylase (ECOD) Activity ---The measurement of ethoxycoumarin Odeethylase (ECOD) activity was performed as described previously. [12][13][14] HepG2 cells treated with CEs were incubated in 0.9 ml of Minimum Essential Medium (GIBCO™/Invitrogen) containing HEPES (final concentration, 12 mM), glucose (final 30 mM) and 7-ethoxycoumarin (final 1 mM) at 37°C for 3 hr, and the reaction was stopped with ice-cold acetone. After centrifugation of the reaction mixture, the pellet was used for determination of the protein concentration with Lowry's method.…”