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The antioxidant effect of compounds is regularly evaluated by in vitro assays that do not have the capability to predict in vivo protective activity or to determine their underlying mechanisms of action. The aim of this study was to develop an experimental system to evaluate the in vivo protective effects of different antioxidant compounds, based on the zebrafish embryo test. Zebrafish embryos were exposed to tert-butyl hydroperoxide (tBOOH), tetrachlorohydroquinone (TCHQ) and lipopolysaccharides from Escherichia coli (LPS), chemicals that are known inducers of oxidative stress in zebrafish. The developmental toxic effects (lethality or dysmorphogenesis) induced by these chemicals were modulated with n-acetyl l-cysteine and N&omega, nitro l-arginine methyl ester hydrochloride, dimethyl maleate and dl-buthionine sulfoximine in order to validate the oxidant mechanism of oxidative stress inducers. The oxidant effects of tBOOH, TCHQ, and LPS were confirmed by the determination of significant differences in the comparison between the concentration&ndash, response curves of the oxidative stress inducers and of the modulators of antioxidant status. This concept was also applied to the study of the effects of well-known antioxidants, such as vitamin E, quercetin, and lipoic acid. Our results confirm the zebrafish model as an in vivo useful tool to test the protective effects of antioxidant compounds.

The developing cardiovascular system of zebrafish is a sensitive target for many environmental pollutants, including dioxin-like compounds and pesticides. Some polychlorinated biphenyls (PCBs) can compromise the cardiovascular endothelial function by activating oxidative stress-sensitive signaling pathways. Therefore, we exposed zebrafish embryos to PCB126 or to several redox-modulating chemicals to study their ability to modulate the dysmorphogenesis produced by PCB126. PCB126 produced a concentration-dependent induction of pericardial edema and circulatory failure, and a concentration-dependent reduction of cardiac output and body length at 80 hours post fertilization (hpf). Among several modulators tested, the effects of PCB126 could be both positively and negatively modulated by different compounds, co-treatment with &alpha, tocopherol (vitamin E liposoluble) prevented the adverse effects of PCB126 in pericardial edema, whereas co-treatment with sodium nitroprusside (a vasodilator compound) significantly worsened PCB126 effects. Gene expression analysis showed an up-regulation of cyp1a, hsp70, and gstp1, indicative of PCB126 interaction with the aryl hydrocarbon receptor (AhR), while the transcription of antioxidant genes (sod1, sod2, cat and gpx1a) was not affected. Further studies are necessary to understand the role of oxidative stress in the developmental toxicity of low concentrations of PCB126 (25 nM). Our results give insights into the use of zebrafish embryos for exploring mechanisms underlying the oxidative potential of environmental pollutants.

The zebrafish embryo is a highly interesting biological model with applications in different scientific fields, such as biomedicine, pharmacology and toxicology. In this study, we used liquid chromatography/electrospray ionisation-linear ion trap quadrupole-Orbitrap-mass spectrometry (HPLC/ESI-LTQ-Orbitrap-MS) to identify the polyphenol compounds in a red wine extract and zebrafish embryos. Phenolic compounds and anthocyanin metabolites were determined in zebrafish embryos previously exposed to the red wine extract. Compounds were identified by injection in a high-resolution system (LTQ-Orbitrap) using accurate mass measurements in MS, MS(2) and MS(3) modes. To our knowledge, this research constitutes the first comprehensive identification of phenolic compounds in zebrafish by HPLC coupled to high-resolution mass spectrometry.

The introduction of chemical products into the environment can cause long-term effects on the ecosystems. Increasing efforts are being made to determine the extent of contamination in particularly affected areas using diverse methods to assess the ecotoxicological impact. We used a modified Frog Embrio Toxicity Assay-Xenopus method to determine the extent of toxicological load in different sample soils obtained near three municipal solid waste landfills in Catalonia (Spain). The results show that the Garraf landfill facility produces more embryotoxic damage to the surroundings, than the others ones: Can Mata landfill and Montferrer-Castellbó landfill. The aim of this work is to demonstrate how different management of complex sources of contamination as the controlled dumping sites can modulate the presence of toxics in the environment and their effects and through this, help determine the safer way to treat these wastes. To this effect some conceptual modifications have been made on the established American Society for Testing and Materials protocol. The validity of the new model, both as to model of calculation as to protocol, has been demonstrated in three different sites with complex sources of contamination.

Summary 1. We examined whether egg fatty acid (FA) profiles and stable isotopes (SIA) could be used in a comparative way to infer the diet of two aquatic bird species with contrasting feeding habits: a surface forager, the pheasant-tailed jacana (Hydrophasianus chirurgus), and a pursuit-diving forager, the little cormorant (Phalacrocorax niger), at Haleji Lake (Pakistan). 2. The species differed markedly in the overall percentage of saturated and polyunsaturated fatty acids. Moreover, among jacanas, two groups of birds had relatively high or low concentrations of long-chain essential PUFAs (such as 18:2 n-6 and 20:4 n-6), suggesting differing contributions from animal prey and plant material. 3. These trophic differences were corroborated by δ15N values which indicated both a higher trophic position in cormorants relative to jacanas, and differences in trophic position for the two groups of jacanas. In this latter species δ13C values in both groups also pointed to differing diets, involving mainly grazing plants or a contribution from animal resources (aquatic invertebrates or insects). 4. Both lower values of δ13C and higher percentages of 18:1 n-7 detected in little cormorants may indicate the influence of the anoxic water, typical of a freshwater system densely covered by macrophytes. 5. These results indicate how both biomarkers offer complementary information in studies of feeding ecology, refining interpretations of trophic pathways which are usually based on FA or SIA alone. Comparisons of FA profiles and SIA among species also proved to be a reliable approach for inferring the diet of species for which information is scarce or contradictory, as is the case for the pheasant-tailed jacana.

A fast and easy to perform method for the routine determination of aflatoxins in medicinal herbs was developed. The described method involves a single-step extraction with a non-chlorinated solvent, an immunoaffinity clean-up and HPLC with fluorescence detection. Whilst assays with naturally contaminated and with spiked samples of several herbs showed that the recoveries were somewhat low and dependent on the kind of sample and the degree of grinding, the intra-batch reproducibility was good, allowing a reliable quantitation by the standard-addition method. Good linearity, repeatability and accuracy were demonstrated in assays involving several medicinal herbs. The limit of quantivation was of the order of 0.05–0.1 ng/g, being dependent of the species analysed, and the method required no tedious concentration or back-extraction steps. Copyright © 2005 John Wiley & Sons, Ltd.

In the last years, consumption of organic foods has become increasingly popular. Nevertheless, safety of organic foods is still unclear, and needs to be thoroughly evaluated. Patulin is a mycotoxin mainly present in rotten apples and apple-based products. The aim of this study is to analyse the content of patulin in apple juices and purees derived from organic and conventional production systems, in order to assess the risk to consumers, particularly in children. A total of 93 apple-based products marketed in Catalonia were analysed, 49 of which were derived from conventional and 44 from organic farming. The results showed higher incidence of positive samples and higher concentration of patulin in organic apple purees when comparing with conventional ones. In the case of juices, significant differences were found between conventional and organic samples, but applying a multivariate analysis the type of agriculture did not seem to have a relevant contribution to patulin occurrence, being cloudiness the main factor involved. The estimated daily intake of patulin for infants and young children (0–3 years old), children (4–18 years old) and adults (19–66 years old), were below the provisional maximum tolerable daily intake (PMTDI) of 0.4 μg/kg bw in all scenarios considered.