Naslov
Multidrug resistance associated protein (MRP) transport activity mediates differences in susceptibility to inorganic and organic mercury in sea urchin (Strongylocentrotus purpuratus) embryos

Autori
Bošnjak, Ivana ; Coale, Kenneth ; Franekić Čolić, Jasna ; Smital, Tvrtko ; Epel, David ; Hamdoun, Amro

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
ABC Transport Proteins in Environmental Health and Toxicology / - Siena, 2007, 22-22

Skup
ABC Transport Proteins in Environmental Health and Toxicology

Mjesto i datum
Siena, Italija, 18.10.2007. - 21.10.2007

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
mercury; MRP; GSH; GST

Sažetak
In this study we compared the protective capacity mediated by the multidrug resistance associated protein (MRP) activity in purple sea urchin (Strongylocentrotus purpuratus) embryos against two forms of mercury, mercuric chloride (HgCl2) and monomethyl mercury (CH3HgCl). To quantify mercury toxicity we assessed the effect of HgCl2 and CH3HgCl on cell division. Our assay detects the incidence of interference with progression through the first cell cycle, which occurs primarily through the effects of mercury on spindles (microtubules) in metaphase and anaphase. We found that the EC50 concentrations for interference with mitosis are 580 nM for HgCl2 and 124 nM for CH3HgCl. Partial inhibition of the MRP mediated efflux activity with 5 &micro ; M MK571, an inhibitor of MRP efflux transporters, increases the toxicity of HgCl2 3.2-fold, but has no effect on the toxicity of CH3HgCl. To test whether embryos defend against mercury using glutathione (GSH) conjugation, we exposed embryos to 500 nM 1-chloro-2, 4-dinitrobenzene (CDNB), a substrate for GSH, or 1 &micro ; M ethacrynic acid (EA), a glutathione S-transferase (GST) inhibitor. CDNB and EA increase HgCl2 toxicity 3.2 and 1.9-fold, respectively. However, neither CDNB nor EA have any effect on CH3HgCl toxicity. Our results indicate that MRP-mediated efflux of mercury, most likely as a GSH conjugate, protects against HgCl2, but not CH3HgCl. These transporter-mediated differences in mercury handling are likely to determine the biological fate of this ubiquitous anthropogenic pollutant.

Izvorni jezik
Engleski

Znanstvena područja
Biotehnologija

POVEZANOST RADA