@article{
author = "Prokić, Marko and Borković-Mitić, Slavica and Krizmanić, Imre and Mutić, Jelena and Vukojević, Vesna and Nasia, Mohamed and Gavrić, Jelena and Despotović, Svetlana and Gavrilović, Branka and Radovanović, Tijana and Pavlović, Slađan and Saičić, Zorica",
year = "2016",
abstract = "Heavy metal pollution of the aquatic environment is of great concern worldwide. Heavy metals are
capable of inducing oxidative stress by increasing the formation of reactive oxygen species (ROS), and
directly affecting the antioxidant defense system (AOS) in living organisms. The frog Pelophylax kl. esculentus is a semiaquatic species with semipermeable skin and a complex lifecycle, and represents a
potentially useful bioindicator organism. The aim of this study was to investigate the accumulation of
several heavy metals (Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb and Zn), and their effects on selected parameters of the
AOS, including the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), glutathione reductase (GR), phase II biotransformation enzyme glutathione-S-transferase (GST), the
total glutathione (GSH) contents and sulfhydryl (SH) group concentrations, as well as cholinesterases
(ChEs) activities in the liver, skin and muscle of P. kl. esculentus. Frog samples were collected at two sites
(the Danube–Tisza–Danube canal (DTDC) and the river Ponjavica) in Serbia, which are characterized by
different levels of metal pollution. Differences between the metal contents in different tissues showed
that the skin of frogs from the DTDC accumulated statistically higher concentrations of Cd, Cu, Pb and Zn,
while only the Fe concentration was lower. No significant differences between metal concentrations in
muscle tissues of frogs from the DTDC and Ponjavica were observed. Examination of the parameters of
the AOS revealed that frogs from the DTDC had higher concentrations of GSH in the liver and of SH
groups in the skin and muscle, whereas the activities of the antioxidative enzymes SOD, GHS-Px and GR
in the liver and of GR in the skin were lower than in frogs from the Ponjavica. The relationship between
metal concentrations and AOS parameters showed the highest number of correlations with GSH, GR and
CAT, and with Ni, Zn, Hg, Cr and Cd. Based on the results in this study, we concluded that increased
concentrations of heavy metals in frog tissues can alter the AOS, which leads to higher concentrations of
GSH and SH groups and lower activities of antioxidative enzymes. The response of the AOS to metal
pollutants allowed us to make a distinction between different frog tissues, and to conclude that the liver
and skin are more suitable for assessing metal-induced oxidative stress in frogs than muscle.",
publisher = "San Diego: Academic Press Inc.",
journal = "Ecotoxicology and Environmental Safety",
title = "Antioxidative responses of the tissues of two wild populations of Pelophylax kl. esculentus frogs to heavy metal pollution",
volume = "128",
doi = "10.1016/j.ecoenv.2016.02.005",
pages = "21-29"
}
