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Dioxin resistance in killifish (Fundulus heteroclitus) from New Bedford Harbor, MA
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Abstracts / Marine Environmental Research 50 (2000) 331±335
Dioxin resistance in killi®sh (Fundulus heteroclitus) from New Bedford Harbor, MA S.B. Bello, D.G. Franks, J.J. Stegeman, M.E. Hahn Woods Hole Oceanographic Institution, Woods Hole, MA 02543 USA
Abstract New Bedford Harbor (NBH), MA, is heavily contaminated with halogenated aromatic hydrocarbons (HAHs) including some potent Ah receptor (AhR) agonists. To determine if NBH Fundulus have developed resistance to HAH, we examined the inducibility of cytochrome P4501A1 (CYP1A1) in ®sh from NBH and Scorton Creek (SC, reference site). In the SC ®sh CYP1A1 RNA, protein and activity, was induced by 2,3,7,8-tetrachlorodibenzofuran (TCDF) in all tissues examined. In contrast, NBH ®sh showed little CYP1A1 induction by any measure, in any tissue. To examine the heritability of this resistance, laboratory-reared ospring of NBH and SC ®sh were treated with [3H]2,3,7,8-tetrachlorodibenzodioxin (TCDD). CYP1A1 was induced in SC ospring, but not in NBH ospring. To investigate the magnitude of this resistance, CYP1A1 was measured in Fundulus primary hepatocyte cultures treated with TCDD or beta-naphtho¯avone (BNF). Hepatocytes from NBH ®sh were 14-fold less sensitive to TCDD than those from SC ®sh, but only three-fold less sensitive to BNF. These results indicate that chronic exposure to high levels of HAH has produced a heritable reduction in the sensitivity of NBH Fundulus to AhR agonists. These ®ndings suggest an alteration in the AhR signal transduction pathway in the dioxin-resistant NBH ®sh; this is the subject of continuing research. (NIEHS ESO7381.) PII: S0141-1136(00)00201-4
Inhibition of multixenobiotic resistance mechanism in aquatic organisms by commercially used pesticides T. Smital, R. Sauerborn, B. PivcÏevicÂ, B. Kurelec Department for Marine and Environmental Research, Ruder BosÏkovic Institute, BijenicÏka 54, 10000 Zagreb, Croatia
Abstract Mechanism of multixenobiotic resistance (MXR), mediated by expression of the transmembrane P-glycoprotein, represents a basic biological defence system in aquatic organisms.
Abstracts / Marine Environmental Research 50 (2000) 331±335
Dioxin resistance in killi®sh (Fundulus heteroclitus) from New Bedford Harbor, MA S.B. Bello, D.G. Franks, J.J. Stegeman, M.E. Hahn Woods Hole Oceanographic Institution, Woods Hole, MA 02543 USA
Abstract New Bedford Harbor (NBH), MA, is heavily contaminated with halogenated aromatic hydrocarbons (HAHs) including some potent Ah receptor (AhR) agonists. To determine if NBH Fundulus have developed resistance to HAH, we examined the inducibility of cytochrome P4501A1 (CYP1A1) in ®sh from NBH and Scorton Creek (SC, reference site). In the SC ®sh CYP1A1 RNA, protein and activity, was induced by 2,3,7,8-tetrachlorodibenzofuran (TCDF) in all tissues examined. In contrast, NBH ®sh showed little CYP1A1 induction by any measure, in any tissue. To examine the heritability of this resistance, laboratory-reared ospring of NBH and SC ®sh were treated with [3H]2,3,7,8-tetrachlorodibenzodioxin (TCDD). CYP1A1 was induced in SC ospring, but not in NBH ospring. To investigate the magnitude of this resistance, CYP1A1 was measured in Fundulus primary hepatocyte cultures treated with TCDD or beta-naphtho¯avone (BNF). Hepatocytes from NBH ®sh were 14-fold less sensitive to TCDD than those from SC ®sh, but only three-fold less sensitive to BNF. These results indicate that chronic exposure to high levels of HAH has produced a heritable reduction in the sensitivity of NBH Fundulus to AhR agonists. These ®ndings suggest an alteration in the AhR signal transduction pathway in the dioxin-resistant NBH ®sh; this is the subject of continuing research. (NIEHS ESO7381.) PII: S0141-1136(00)00201-4
Inhibition of multixenobiotic resistance mechanism in aquatic organisms by commercially used pesticides T. Smital, R. Sauerborn, B. PivcÏevicÂ, B. Kurelec Department for Marine and Environmental Research, Ruder BosÏkovic Institute, BijenicÏka 54, 10000 Zagreb, Croatia
Abstract Mechanism of multixenobiotic resistance (MXR), mediated by expression of the transmembrane P-glycoprotein, represents a basic biological defence system in aquatic organisms.