Zdeňka Svobodová

Oxidative stress responses in zebrafish Danio rerio after subchronic exposure to atrazine.

Atrazine is one of the most used pesticides all over the world and it is frequently detected in surface water. The aim of this study was to investigate if zebrafish exposure to atrazine could induce oxidative stress and changes in detoxifying system. Juvenile fish were exposed to sublethal concentrations of 0.3, 3, 30, or 90 μg L(-1) for 28 days. The level of oxidized lipids increased in experimental groups exposed to atrazine at 30 and 90 μg L(-1) compared to control. Activity of glutathione S-transferase decreased in group with the highest concentration compared to control. A significant decline was observed in catalase activity in all experimental groups compared to control. Activity of superoxide dismutase increased only in experimental group exposed to atrazine at 30 μg L(-1) compared to control. Activity of glutathione peroxidase and reductase (GR) increased in experimental groups exposed to atrazine at 0.3 (only for GR activity) and 90 μg L(-1) compared to control. Our results showed that atrazine exposure had profound influence on the oxidative stress markers and detoxifying enzyme of the exposed zebrafish. The changes in antioxidant enzyme activities could be an adaptive response to protect the fish from the atrazine-induced toxicity.

The effect of oyster mushroom β-1.3/1.6-D-glucan and oxytetracycline antibiotic on biometrical, haematological, biochemical, and immunological indices, and histopathological changes in common carp (Cyprinus carpio L.)

The aim of the study was to evaluate the effect of micronized β-1.3/1.6-D-glucan (BG) derived from the oyster mushroom Pleurotus ostreatus Hiratake and tetracycline antibiotic oxytetracycline (OTC) on biometrical, haematological, biochemical, and immunological indices, and histopathological changes in tissues of one- to two-year-old common carp (Cyprinus carpio L.). The fish tested were divided into five experimental groups and one control. Carp in the control group were fed commercial carp feed pellets. Fish in the five experimental groups were fed the same pellets supplemented with either OTC, a combination of OTC and BG, or BG as follows: 75 mg oxytetracycline kg(-1) bw (OTC group), 75 mg oxytetracycline kg(-1) bw and 0.5% β-glucan (OTC + 0.5% BG group), 75 mg oxytetracycline kg(-1) bw and 2.0% β-glucan (OTC + 2.0% BG group), 0.5% β-glucan (0.5% BG group), and 2.0% β-glucan (2.0% BG group). OTC- and BG-supplemented diets and the control diet were administered to experimental and control carp for 50 days (i.e. samplings 1-3, the exposure period); for the following 14 days, fish were fed only control feed pellets with no OTC or BG supplementation (i.e. sampling 4, the recovery period). Blood and tissue samples were collected both during, and at the end of the study. No significant changes in biometrical indices (i.e. total length, standard length, total weight, hepatosomatic and spleen somatic index, and Fultons condition factor) were found in experimental carp compared to control in any sampling. In haematological indices, significant changes were found only in sampling 2, in which shifts in PCV (P < 0.01), Hb (P < 0.01), and WBC (P < 0.01), and in the counts of lymphocytes (P < 0.01), monocytes (P < 0.01), and neutrophil granulocytes-segments (P < 0.05) were revealed. As for biochemical profiling, plasma concentrations of glucose, albumins, cholesterol, natrium, and chlorides (all P < 0.01), and total proteins, lactate, phosphorus, and potassium (all P < 0.05) as well as the catalytic activity of ALP (P < 0.05) were altered in common carp. A significant change in induced (opsonizedzymosan particles, OZP) chemiluminescence (P < 0.05) in sampling 3 and no shifts in serum immunoglobulins concentration were found in the immunological analysis. Histopathological examination of skin, gills, liver, spleen, and cranial and caudal kidneys revealed no obvious specific changes in any tissue analysed. The use of β-glucans in clinically healthy aquaculture remains an issue. Nevertheless, their use in breeding endangered by stress stimuli, infectious disease, or adverse environmental factors is defensible.

Assessment of contamination of the Svitava and Svratka rivers in the Czech Republic using selected biochemical markers

The aim of the present study is to assess aquatic ecosystem contamination using selected biochemical markers: cytochrome P450, ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), tripeptide glutathione, vitellogenin, and 11-ketotestosterone in chub (Leuciscus cephalus L.). Seven locations on the Svitava and Svratka rivers (in the Brno conurbation, Czech Republic) were assessed. The results were compared with the levels of the most important inductors of these biomarkers: organic pollutants hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), DDT and its metabolites, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons in bottom sediment, fish muscle, and semipermeable membrane devices (SPMDs) and metals in sediment. The highest levels of pollutants were observed at sites situated downstream from Brno, especially at Modrice and Rajhradice. Significant positive correlations (p < 0.05) were found between EROD activity and HCH concentration in SPMDs, and also between GST and EROD activity with HCB concentration in muscle, after adjusting for age.

Mercury speciation in fish muscles from major Czech rivers and assessment of health risks.

The aim of this work was to determine the mercury and methylmercury content in muscle tissue of chub (Leuciscus cephalus L.), to assess the health risks of eating the fish and to determine the number of fish meat servings that are suitable for weekly consumption. Total mercury concentrations were determined using a single-purpose atomic absorption spectrophotometer AMA 254. Methylmercury concentrations were determined by gas chromatography. The location where the highest total mercury concentrations in fish muscle tissues were found was the Vltava - Vraňany (0.236±0.1001mg/kg(-1)), and the highest methylmercury concentration was found at the Labe - Obříství (0.231±0.1056mg/kg(-1)). The conclusion based on the data ascertained is that the locations from which the lowest number of fish meat servings can be eaten are the Vltava - Vraňany and the Labe - Obříství. The results of this study helped evaluate contamination levels of rivers that flow out of the Czech Republic.

Organochlorine Compound Residues in Muscle of Wild Boar (Sus scrofa L.) and Red Deer (Cervus elaphus L.): Effects of Age and Sex

Twenty-six organochlorine pesticides and 7 polychlorinated biphenyls were measured in muscle of wild boar and red deer from the Czech Republic. The concentration of DDT and its metabolites was higher (pxa0<xa00.01) in wild boar than in red deer, while PCBs and HCH were higher (pxa0<xa00.01) in red deer than in wild boar. The concentrations of DDT and its metabolites, hexachlorobenzene and hexachlorocyclohexane isomers were higher (pxa0<xa00.05) in juvenile wild boar than in adults. PCB 153 and p,p′-DDE were the most prominent pollutants in both red deer and wild boar.

TURKUSOWE LAKE (WOLIN ISLAND, POLAND) - SURFACE WATERS QUALITY CHANGES IN YEARS 1986-2010

Abstract After presentation of the characteristics of a water reservoir in CaCO3 excavation pit, called the Turkusowe Lake, situated in the Wolin National Park on the Wolin Island, available results of the analyses referring to the quality of surface water of this water reservoir and being carried out since 1986 as well as those of own studies being carried out from 1999 to 2010 were gathered, collecting this way a research material covering the quarter-century 1986-2010. It was shown that the Turkusowe Lake is a water reservoir being resistant by nature to eutrophication (lake basin development and depth, surrounding by the heights adhering to it, and presence of CaCO3 building the lake basin), whereas an increase in the trophic level and development of eutrophication phenomena in the form of weak phytoplankton blooms being observed, particularly in 2005-2010, is connected with increased anthropogenic pressure in the form of direct discharge of municipal sewage to the lake and waste-water to the soil in the alimentation zone of underground waters feeding this lake. The extent of anthropogenic pressure was so big that it started to prevail over the natural processes limiting an increase in the trophic level in this lake.