Use of multiple tools to assess the feeding preference of coastal dolphins

The feeding preferences of the coastal dolphins Pontoporia blainvillei and Sotalia guianensis in south-eastern Brazil (21o18′S–22o25′S) were assessed through the prey’s index of relative importance (IRI), total mercury concentration (Hg_tot), and stable isotopic (δ¹⁵N and δ¹³C) to compare their efficiency in the discrimination of prey contribution to the predators’ diet. The IRI was the best tool to describe the dolphins’ preference, while Hg_tot and δ¹⁵N seemed to be efficient as a trophic marker when the diet is made up of prey of varying sizes, as observed in S. guianensis. Both dolphins presented lighter δ¹⁵N than their prey species, which is an unusual pattern. However, as the sample size to isotope ratios analysis was small, especially to the dolphins, the results should be considered with caution, and further studies are necessary to corroborate these findings. The δ¹³C values characterized a typical coastal food chain, confirming the preferential area of these species.     

Paramagnetic antibody-modified microparticles coupled with voltammetry as a tool for isolation and detection of metallothionen as a bioindicator of metal pollution

Low-molecular mass proteins rich in cysteines called metallothioneins (MT) can be considered as markers for the pollution of the environment by metals. Here, we report on suggestion for an automated procedure for the isolation of MT followed by voltammetric analysis. Primarily, we optimized the automated detection of MT using an electrochemical analyser. It was found that the most sensitive and repeatable analyses are obtained at a temperature of 4 °C for the supporting electrolyte. Further, we optimized experimental conditions for the isolation of MT by using antibody-linked paramagnetic microparticles. Under the optimal conditions (4 h long interaction between the microparticles and MT), the microparticles were tested on isolation of various amounts of MT. The lowest isolated amount of MT by antibody-linked paramagnetic microparticles was 5 μg ml(-1) of MT (50 ng). The automated procedure of MT isolation was further tested on isolation of MT from guppy fish (Poecilia reticulata) treated with silver(i) ions (50 μM AgNO(3)). The whole process lasted less than five hours and was fully automated. We attempted to correlate these results with the standard method for MT isolation. The correlation coefficient is 0.9901, which confirms that results are in good agreement. Moreover, the concentration of silver ions in tissues of fish treated with Ag(i) ions was determined by high performance liquid chromatography with electrochemical detection.     

Coating independent cytotoxicity of citrate- and PEG-coated silver nanoparticles on a human hepatoma cell line

The antibacterial potential of silver nanoparticles(AgNPs) resulted in their increasing incorporation into consumer,industrial and biomedical products.Therefore,human and environmental exposure to AgNPs(either as an engineered product or a contaminant)supports the emergent research on the features conferring them different toxicity profiles.In this study,30 ran AgNPs coated with citrate or poly(ethylene glycol)(PEG) were used to assess the influence of coating on the effects produced on a human hepatoma cell line(HepG2),namely in terms of viability,apoptosis,apoptotic related genes,cell cycle and cyclins gene expression.Both types of coated AgNPs decreased cell proliferation and viability with a similar toxicity profile.At the concentrations used(11 and 5 μg/mL corresponding to IC50 and-IC10 levels,respectively) the amount of cells undergoing apoptosis was not significant and the apoptotic related genes BCL2(anti-apoptotic gene)and BAX(pro-apoptotic gene) were both downregulated.Moreover,both AgNPs affected HepG2 cell cycle progression at the higher concentration(11 μg/mL) by increasing the percentage of cells in S(synthesis phase) and G2(Gap 2 phase) phases.Considering the cell-cycle related genes,the expression of cyclin B1 and cyclin E1 genes were decreased.Thus,this work has shown that citrate- and PEG-coated AgNPs impact on HepG2 apoptotic gene expression,cell cycle dynamics and cyclin regulation in a similar way.More research is needed to determine the properties that confer AgNPs at lower toxicity,since their use has proved helpful in several industrial and biomedical contexts.     

Biosorption of Phosphorus Using Alginate-Like Exopolymers: Investigation of Removal Mechanism,Kinetic and Thermodynamic Properties

Journal of Polymers and the Environment - The purpose of this study was to investigate the phosphorus (P) adsorption mechanism, kinetic, isothermal and thermodynamic parameters using alginate-like...     

Factors driving sediment compositional change in the distal area of the Ria de Vigo (NW Spain): oceanographic processes vs. paleopollution

Environmental Science and Pollution Research - We analyze potential Late Holocene metal contamination along a sediment core collected in the distal zone of Ria de Vigo (North Spain). Statistical...     

Consumer Autonomy and Sufficiency of GMF Labeling

Individuals’ food choices are intimately connected to their self-images and world views. Some dietary choices adopted by consumers pose restrictions on their use of genetically modified food (GMF). It is quite generally agreed that some kind of labeling is necessary for respecting consumers’ autonomy of choice regarding GMF. In this paper, we ask whether the current practice of mandatory labeling of GMF products in the European Union is a sufficient administrative procedure for respecting consumers’ autonomy. Three issues concerning this question are discussed. First, we argue that labeling needs to be accompanied by relevant and understandable information on genetic modification, genetically modified food, and the European practice of GMF labeling. Second, we claim that this type of informing makes it less likely that consumers start to avoid GMF products just because labels make them suspicious of the products. It is further noted that even though some consumers may react to labels this way, labels do not restrict their autonomy of choice. Third, a need for more precise labels indicating the source of the transferred gene is considered. It is found out that such labels are not morally necessary when also non-GMF products are available and no relevant differences (such as differences in price and healthiness) exist between them and GMF products. However, in some other cases more precise labels may be needed for respecting consumers’ autonomy of choice.