Biomarkers of Contaminant Exposure in Chub (Leuciscus cephalus L.) - Biomonitoring of Major Rivers in the Czech Republic

The benefit of using in vitro bioassays to screen agricultural samples for oxidative stress: South Africa's case

Applied pesticides end up in non-target environments as complex mixtures. When bioavailable, these chemicals pose a threat to living organisms and can induce oxidative stress (OS). In this article, attention is paid to OS and the physiological role of the antioxidant defense system. South African and international literature was reviewed to provide extensive evidence of pesticide-induced OS in non-target organisms, in vivo and in vitro. Although in vitro approaches are used internationally, South African studies have only used in vivo methods. Considering ethical implications, the authors support the use of in vitro bioassays to screen environmental matrices for their OS potential. Since OS responses are initiated and measurable at lower cellular concentrations compared to other toxicity endpoints, in vitro OS bioassays could be used as an early warning sign for the presence of chemical mixtures in non-target environments. Areas of concern in the country could be identified and prioritized without using animal models. The authors conclude that it will be worthwhile for South Africa to include in vitro OS bioassays as part of a battery of tests to screen environmental matrices for biological effects. This will facilitate the development and implementation of biomonitoring programs to safeguard the South African environment.

Assessment of pollution with biomarkers in fish culture

Biotransformation enzymes are stimulated or inhibited depending on the exposure to xenobiotics and widely used as a biomarker. In this study, EROD activity, GST activity, reduced GSH amount, amount of lipid peroxidation product MDA as oxidative stress parameter, and ACHE inhibition as a neuromuscular parameter were measured in liver and muscle tissues of rainbow trout (Oncorhynchus mykiss) produced in aquaculture of Kemer Dam and in concrete ponds located in Fethiye. Samples were collected in January and July from fish farming in net cages in Kemer Dam and concrete cages in Fethiye in order to evaluate seasonal changes. Also, physicochemical properties of water samples collected from trout farms were measured and evaluated together with five biomarkers. Significant ACHE inhibition was observed in both stations in parallel with the increase in ammonium nitrogen in the July period (p ≤ 0.05). In parallel with the increase in turbidity in the Kemer Dam, a significant increase in GSH, MDA level, and GST activity was detected (p ≤ 0.05). As a result of the assessment of all data, significant increases were detected in EROD induction, GST activity, MDA level, and ACHE inhibition in concrete cages in Fethiye when compared to Kemer Dam (p ≤ 0,05). It was observed that pollution was at a lower level in July compared to January, and in Kemer Dam compared to Fethiye.

Assessment of the effects of atrazine, dichlorodiphenyltrichloroethane, and dimethoate on freshwater fish (Oreochromis mossambicus): a case study of the A2 farmlands in Chiredzi, in the southeastern part of Zimbabwe

A study was carried out to assess the levels and effects of atrazine, dimethoate, and dichlorodiphenyltrichloroethane on freshwater fish (Oreochromis mossambicus). Water and fish were sampled once from a dam within the Hippo Valley A2 farmlands in Chiredzi, in the southeastern part of Zimbabwe. The samples were screened for atrazine, dimethoate, and dichlorodiphenyltrichloroethane (DDT), the pesticides commonly used in the region. Atrazine and dimethoate are pesticides commonly used in the control of weeds and pests in the agricultural production of sugarcane in Hippo Valley, Chiredzi region. The effects of the pesticides on biochemical endpoints of the sampled fish were determined. The analyzed biochemical end parameters were superoxide dismutase, catalase, glutathione S-transferase, and glutathione peroxidase activities in liver and white muscle fish extracts. Dichlorodiphenyltrichloroethane was observed in water and fish muscle tissue at concentrations of 131.3 μg/l and 171.7 μg/kg, respectively, while atrazine was detected at concentrations of 6.15 μg/l and 142.0 μg/kg in water and fish muscle tissue, respectively. The observed concentrations of atrazine and DDT in water samples were above the limits permissible by the World Health Organization in drinking water. Dimethoate was found in concentrations of 4.21 μg/l and 1.30 μg/kg in water and fish muscle tissue respectively. The observed concentration of dimethoate in water was below the acceptable limit set by the Guidelines for Canadian Drinking Water. Antioxidant enzyme activities were increased significantly (p < 0.05) in fish exposed to water from Hippo Valley, Chiredzi, when compared with the controls. The enhanced activities of the studied antioxidant enzyme system were attributed to exposure to pollutants in the water body. Alterations of the biochemical integrity of fish indicate negative effects of the pesticides on the well-being of fish and undoubtedly other aquatic biota as well.

Evaluation of the multiple biomarkers on identification of the vulnerable coastal pollution hotspots

This paper presents multiple biomarkers on metal accumulation and its impacts along the Chennai to Puducherry, southeast coast of India using bivalves as bioindicators. In this regard, water samples and Perna viridis were collected from three stations and the accumulation of metals and its biological impacts were assessed. Among the three sampling stations, the maximum accumulation was noticed in Ennore (S1) than the Puducherry (S3) followed by Kovalam (S2). Mean accumulation pattern of metals in Perna viridis was found to be in the following order Zn > Cu > Ni > Cr > Pb > Cd, which were in close match with the metal concentration in seawater at respective site. The ambient metal concentration and behavior of multiple biomarkers were positively correlated indicating that the uptake of metals might induce biological changes, particularly in the internal organs, thus significantly affecting health of the aquatic organisms. P. viridis provides reliable information concerning the adverse effects and reflects the integrated effects of all contaminants. Thus, study confirmed that Ennore (S1) coast is highly vulnerable for significant pollution, in terms of metal toxicity in the study area. Overall investigation revealed that metal enrichment was observed close to the major urban areas in the S1 and S2 which were associated with industrialized areas. The assessment of multiple biomarkers on metal accumulation was the first step in determining the trophic transfer factors on marine foot web, which can be evaluated in the future based on this study.

Mercury concentrations in commercial fish from freshwater and saltwater

Research was performed to investigate the concentration of mercury in muscle and liver of fish species from freshwater (Barbus xanthopterus, Barbus grypus, Liza abu) and saltwater (Cynoglossus arel, Periophthalmus waltoni, Otolithes ruber) in Khouzestan, Iran. In freshwater fish, muscle was polluted in comparison with liver except for Barbus xanthopterus which high levels of mercury were measured in liver. In saltwater fish liver was contaminated than muscle except for Cynoglossus arel which high level of mercury was found in muscle. Significant variations in metal values were evaluated using student's t test at P < 0.05. Mercury concentrations were well above the permissible limits suggested by WHO and FDA guidelines.

Determination of heavy metals in two barbs, Barbus grypus and Barbus xanthopterus in Karoon and Dez Rivers, Khoozestan, Iran

Cadmium, lead, nickel and mercury were contamination in gill, liver and muscle of B. grypus and B. xanthopterus in Karoon and Dez Rivers. Significant variations in metal values were evaluated using student's t test at p < 0.05. In B. grypus high levels of cadmium, lead, nickel and mercury were measured in gill (1.49, 2.25, 1.02 and 0.89 mg kg(-1) dw) except for mercury (1.06 mg kg(-1) dw) in B. grypus in Dez River was high in liver. In B. xanthopterus high levels of cadmium, lead, nickel and mercury were measured in gill (2.17, 2.91 and 1.43 mg kg(-1) dw) except for mercury (1.42 mg kg(-1) dw) high levels were measured in liver.

Biochemical markers for the assessment of aquatic environment contamination

The need for assessment of aquatic ecosystem contamination and of its impact on water dwelling organisms was developed in response to rising aquatic environmental pollution. In this field study, liver enzymes of phase I and phase II of xenobiotic transformation, namely cytochrome P450, ethoxyresorufin-O-deethylase, glutathione-S-transferase and tripeptide glutathione were used to assess the contamination of the aquatic environment at different rivers in the Czech Republic. The indicator species selected was the male chub (Leuciscus cephalus L.) and male brown trout (Salmo trutta fario). Chemical analyses included also the assessment of the most important inductors of previously mentioned biochemical markers. The major inductors of monitored biomarkers are industrial contaminants which belong to a large group of organic pollutants (PCB, PAH, PCDD/F, DDT, HCH, HCB and OCS), persistent in the environment. Four different groups of river basins were assessed: the River Tichá Orlice and its tributary the Kralický brook; important tributaries of the River Elbe (the rivers Orlice, Chrudimka, Cidlina, Jizera, Vltava, Ohře and Bílina); major rivers in the Czech Republic (the rivers Lužnice, Otava, Sázava, Berounka, Vltava, Labe, Ohře, Svratka, Dyje, Morava and Odra) and the River Vltava. The use of the biochemical markers together with chemical analyses seems to be an effective way to monitor the quality of aquatic environment.

Fish hepatic glutathione-S-transferase activity is affected by the cestode parasitesSchistocephalus solidusandLigula intestinalis: evidence from field and laboratory studies

The activity of hepatic glutathione-S-transferase (GST) was analysed in 3 different fish species with respect to fish sex and infection with parasites. In both sexes of laboratory bred three-spined sticklebacks (Gasterosteus aculeatus)experimentally infected withSchistocephalus solidus(Cestoda), a significantly lower GST-activity was found for infected fish compared to control. After field sampling of roach (Rutilus rutilus) from Lake Müggelsee (MS) and the Reservoir Listertalsperre (LTS), the GST-activity showed significantly lower values for males infected withLigula intestinalisfrom MS (25%) and for infected females from LTS (55%).L. intestinalis-infected female chub (Leuciscus cephalus) from LTS also appeared to have a lower GST-activity. Thus, it could be shown that the presence of parasites significantly affects GST-activity in different fish species resulting in a decreased GST-activity due to infection. Our results therefore emphasize the need for more integrative approaches in environmental pollution research to clearly identify the possible effects of parasites in an effort to develop biomarkers for evaluating environmental health.

Organochlorine pollutants in chub, Leuciscus cephalus, from the Svratka River, Czech Republic

The aim was to evaluate the extent of pollution of the Svratka River with organochlorinated pollutants using the chub (Leuciscus cephalus) as a suitable bioindicator of the river contamination. The sum of 7 PCB congeners was found in range of 7.6-93.8 ng/g (with median of 31.7 ng/g) wet weight (ww), DDTs of 2.9-93.8 (29.9) ng/g ww, HCHs isomers of 0.1-5.3 (1.0) ng/g ww, HCB of 0.3-8.4 (2.2) ng/g ww and OCS of <0.1-0.5 (0.1) ng/g ww. Our results confirm predominance of metabolite DDE and higher-chlorinated PCB congeners and are comparable with similar studies and findings within the Czech Republic.

1-Hydroxypyrene--a biochemical marker for PAH pollution assessment of aquatic ecosystem

The aim of the present study was to assess aquatic contamination by polycyclic aromatic hydrocarbons (PAH), using the 1-hydroxypyrene (1-OHP) content in fish bile as a biochemical marker. A total of 71 chub (Leuciscus cephalus L.) were collected from seven locations on the Svitava and Svratka rivers in and around the industrial city of Brno, Czech Republic. The levels of 1-OHP were determined by reverse phase HPLC with fluorescence detection after deconjugation. Normalising the molar concentration of the biliary 1-OHP to the biliary protein content reduced sample variation. The content of 1-OHP was correlated with the PAH level in bottom sediment and semi-permeable membrane devices (SPMD), which was analyzed by a combination of HPLC/FLD and GC/MS methods. The highest mean values of 1-OHP were found in fish caught at the Svratka River at locations Modřice (169.2 ± 99.7 ng·mg⁻¹ protein) and Rajhradice (152.2 ± 79.7 ng·mg⁻¹ protein), which are located downstream from Brno. These values were significantly (P < 0.05) higher than those obtained from localities Kníničky (98.4 ± 66.1 ng·mg⁻¹ protein) and Bílovice nad Svitavou (64.1 ± 31.4 ng·mg⁻¹ protein). The lowest contents of PAH in sediment and SPMD were found at location Kníničky (1.5 mg·kg⁻¹ dry mass and 19.4 ng·L⁻¹, respectively). The highest contents of PAH in sediment and SPMD were found in Rajhradice (26.0 mg·kg⁻¹ dry mass) and Svitava before junction (65.4 ng·L⁻¹), respectively. A Spearman correlation test was applied to determine the relationship between biliary 1-OHP and the sum of PAH in sediment and SPMD. A positive, but no statistically significant correlation was found. The main impact sources of elevated level of PAHs in sites located downstream from Brno are most probably intensive industrial and agricultural activities and domestic waste.

Can thiol compounds be used as biomarkers of aquatic ecosystem contamination by cadmium?

Due to anthropogenic activities, heavy metals still represent a threat for various trophic levels. If aquatic animals are exposed to heavy metals we can obviously observe considerable toxicity. It is well known that an organism affected by cadmium (Cd) synthesize low molecular mass thiol compounds rich in cysteine (Cys), such as metallothioneins (MT) and glutathione (GSH/GSSG). The aim of this study was to summarize the effect of Cd on level of thiol compounds in aquatic organisms, and evaluate that the concentrations of thiol compounds are effective indicators of Cd water pollution and explain their potential use in biomonitoring applications.

EROD and MROD as Markers of Cytochrome P450 1A Activities in Hepatic Microsomes from Entire and Castrated Male Pigs

In the present study, we characterized the kinetic parameters of 7-ethoxy-resorufin O-deethylation (EROD) and 7-methoxyresorufin O-demethylation (MROD) in hepatic microsomes from entire and castrated male pigs. Validation parameters of an HPLC-based method to analyse EROD and MROD activities are also described. Eadie-Hofstee plot analysis demonstrated a biphasic kinetic of EROD, indicating that at least two forms of cytochrome P450 are involved in this reaction. MROD followed monophasic kinetic, suggesting that a single enzyme, or enzymes with similar affinities, is responsible for the reaction. Inhibitory effects of α-naphthoflavone (ANF), ellipticine and furafylline were studied using microsomes from entire and castrated male pigs. ANF is a known inhibitor of both cytochrome P₄₅₀ 1A1 and 1A2 (CYP1A1 and CYP1A2); the presence of ANF in the incubations resulted in the inhibition of both EROD and MROD activities in porcine liver microsomes. EROD activities in porcine liver microsomes were also inhibited by selective CYP1A1 inhibitor ellipticine, but not by CYP1A2 inhibitor furafylline. MROD activities were strongly inhibited by ellipticine and to a much lesser extent by furafylline. Further studies are needed to evaluate substrate specificities of porcine CYP1A1 and CYP1A2.

Leeches as Sensor-bioindicators of River Contamination by PCBs

The aim of the study was to evaluate the use of leeches of the genus Erpobdella as a means of assessing polychlorinated biphenyl contamination of watercourses. The River Skalice, heavily contaminated with PCBs, was selected as a model. The source of contamination was a road gravel processing factory in Rožmitál pod Třemšínem from which an estimated 1 metric ton of PCBs leaked in 1986. Levels of PCB were measured in leeches collected between 1992 to 2003 from 11 sites covering about 50 km of the river (the first sampling site upstream to the source of contamination and 10 sites downstream). The PCB indicator congeners IUPA no. 28, 52, 101, 118, 138, 153, and 180 were measured. Levels were highest at the four sampling sites nearest the source of pollution. The highest values of PCB congeners were found in 1992. PCB content decreased from 1992 to 2003 and with distance from the source. The study indicated that leeches of the genus Erpobdella are a suitable bioindicator of contamination in the surface layer of river sediments.

Utilization of Electrochemical Sensors and Biosensors in Biochemistry and Molecular Biology

A special issue of Sensors entitled “Utilization of Electrochemical Sensors and Biosensors in Biochemistry and Molecular Biology” has been prepared over a period of three years. In this Editorial Note we would like to highlight one of the possible directions for electrochemical sensor and biosensor research resulting from the ideas of Czechoslovakian Nobel Prize winner Jaroslav Heyrovsky and his colleague Rudolf Brdicka.

Comparison of Mercury Distribution Between Liver and Muscle - A Biomonitoring of Fish from Lightly and Heavily Contaminated Localities

Tissue samples from 1,117 fish of 25 species were collected from 1991 through 1996 at 13 locations along the River Elbe. The principal indicator species were perch (Perca fluviatilis) (n=118), chub (Leuciscus cephalus L.) (n=113) and roach (Rutilus rutilus) (n=138). Mercury (Hg) concentrations in muscle and liver were determined by atomic absorption spectrometry. The liver/muscle index in three indicator species from heavily contaminated and lightly contaminated localities were significantly different. In fish from heavily contaminated localities, Hg was deposited preferentially in the liver (the depository for inorganic and organic forms of Hg), while in lightly contaminated areas, it was deposited preferentially in muscle.