title: Receptor-mediated in vitro bioassay for characterization of Ah-R-active compounds and activities in sediment from Korea.
abstract: Sediment extracts of stream sediments, collected from inland areas of Lake Shihwa (LSI) and Masan Bay (MBI), were screened for their abilities to induce aryl hydrocarbon receptor (Ah-R) mediated gene expression in vitro. Cell viability assay was also performed to examine cytotoxic effects on the Ah-R-mediated activities of sediment samples. Over 80% (30 out of 36) of sediment raw extracts (REs) induced significant Ah-R-mediated activities in the H4IIE-luc cell bioassays. Ah-R-mediated activities of sediment REs from LSI locations (mean=58%-TCDD-max; n=21) were greater than those of sediment REs from MBI locations (mean=35%-TCDD-max; n=15), in general. Seven (mean+/-SD=100+/-14%-TCDD-max) of 21 sediment REs from LSI showed Ah-R-mediated activities comparable to that (set to, 100%-TCDD-max) elicited by 1240 pM TCDD. Whereas, in MBI, only two REs from M1 (93%-TCDD-max) and M9 (82%-TCDD-max) showed significantly great responses that comparable to maximum response of TCDD standard curve. Sample potencies relative to the TCDD standard (TCDD-EQs) were estimated based on full dose-response characteristics of REs and TCDD-EQs were found to be 14-868 pg TCDD/g, dw and 17-275 pg TCDD/g, dw, in LSI and MBI, respectively. A range of TCDD-EQ20-80 of samples, based on multiple estimates of relative potency (REP20-80), did not vary greatly (2-4-fold) in the H4IIE-luc bioassays, which indicated relatively low degree of uncertainties in point estimates of REP for sediment REs examined. Acid-treatment of REs samples improved quantitative biological responses of samples followed by decreases in cytotoxicity identified by MTT cell viability assays.
authors.affiliation: National Food Safety and Toxicology Center, Department of Zoology, Institute for Environmental Toxicology, Michigan State University, 218C, Aquatic Toxicology, NSFTC, East Lansing, MI 48824, USA. yoohoon@msu.edu
authors.forename: Hoon
authors.initials: H
authors.lastname: Yoo
authors.forename: Jong Seong
authors.initials: JS
authors.lastname: Khim
authors.forename: John P
authors.initials: JP
authors.lastname: Giesy
mesh_terms: D002470:Cell Survival / Q000187:drug effects*; D019015:Geologic Sediments / Q000032:analysis*; D066298:In Vitro Techniques; D007723:Korea; D008156:Luciferases / Q000096:biosynthesis; D000072317:Polychlorinated Dibenzodioxins / Q000032:analysis / Q000633:toxicity*; D018336:Receptors, Aryl Hydrocarbon / Q000187:drug effects* / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*
chemical_list: D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; D014874:Water Pollutants, Chemical; D008156:Luciferases