Influence of the extraction conditions on chia oil quality and partially defatted flour antioxidant properties.

Partially defatted chia flour (PDCF) is a by-product of oil extraction from chia seeds (Salvia hispanica L.). It may be used as an ingredient to improve food products, especially due to its antioxidant properties. In this work, we studied the best screw press extraction conditions that allow preserving the antioxidant properties of PDCF. A central composite design was applied to perform a response surface analysis in order to optimize the oil extraction. The variables considered for optimization were seed moisture content and pressing temperature. Besides the oil quality indicators, the study was focused on the assessment of PDCF properties, including total polyphenol content and antioxidant capacity determined by chemical methods. Our results show that, within the range of screw press conditions evaluated, the chemical quality of the oil and the antioxidant properties of PDCF are both preserved. The best results (highest oil yield and stability) were obtained under a seed moisture content of 10.2% and a pressing temperature of 58.5 °C. In general, our results indicate that screw press methodology can be applied to process chia seeds, using a wide range of conditions, to concurrently produce good quality oil and a PDCF with beneficial properties.

Antioxidant properties and phenolic composition of "Composed Yerba Mate".

Yerba mate contains bioactive compounds, and is widely consumed as a decoction beverage in several Southern American countries. At present, the consumption of mate with added herbal blends and flavors, called "composed yerba mate", has increased; however, no studies on the antioxidant characteristics of these products have been published. In this sense, the main objective was to assess the antioxidant characteristics of "composed yerba mate" compared to "traditional yerba mate", in the form it is traditionally consumed. Total polyphenols content ranged from 15 to 45 mg/g GAE in all decoctions analyzed. Seventeen phenolic compounds were identified and quantified by HPLC-DAD-MS/MS, mainly belonging to the caffeoylquinic acids group. The antioxidant capacity was measured using in vitro assays, Ferric reducing ability of plasma (FRAP) and Trolox equivalent antioxidant capacity (TEAC), and with Saccharomyces cerevisiae as the in vivo model organism. All decoctions displayed antioxidant activity and were capable of rescuing yeast cells between 10.68 and 18.38% from oxidative stress. Multiple regression analysis showed a high correlation between phenolic composition and activity of samples, where different compounds indicate a significant contribution to the observed activity. Significant differences were found in the content, profile and antioxidant activity of polyphenols when "traditional yerba mate" and "composed yerba mate" were compared. In some cases, the antioxidant capacity was similar or higher in composed yerba mate; while the rest displayed lower biological activity. Based on these findings, it would be possible to assume that the addition of herb mixtures modifies the antioxidant and biological properties of mate. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at (10.1007/s13197-020-04961-x).

Proteomic analysis of Saccharomyces cerevisiae to study the effects of red wine polyphenols on oxidative stress.

Understanding the molecular mechanisms underlying the "French paradox" has contributed to a growing interest in the investigation of the biological activity of red wine polyphenols (RWP). The main goal of this research is to provide valuable information on how RWP could exert their biological action at the cellular level. So, we report a proteomic analysis of S. cerevisiae exposed to both pro-oxidant (H2O2) and antioxidant (wine) agents. Cellular proteome analysis shows that RWP modify the level of certain proteins. Under both normal conditions (Wine treatment) and oxidative stress situations (Wine + H2O2 treatment), the proteins involved in the metabolism and biosynthesis of biomolecules were down-regulated, while one ribosomal protein was up-regulated, probably performing its ribosome-independent functions, and so contributing to the stress defense system. Considering this action mechanism, we suggest that RWP may be acting as mild pro-oxidants and, therefore, exerting a hormetic effect that leads to the strengthening of cells' antioxidant capacity.

Bioaccumulation and trophic transfer of metals, As and Se through a freshwater food web affected by antrophic pollution in Córdoba, Argentina.

The concentration of metals (Al, Cr, Mn, Fe, Ni, Cu, Zn, Ag, Cd, Hg, Pb, U), As and Se in different ecosystem components (water, sediment, plankton, shrimp, and fish muscle) has been determined in a eutrophic reservoir in the Province of Córdoba (Argentina). Los Molinos Lake (LML) was sampled during the dry (DS) and wet seasons (WS) in order to examine the bioaccumulation and transfer of these inorganic elements through the food web. Stable nitrogen isotope (δ15N) was used to investigate trophic interactions. According to this, samples were divided into three categories: plankton, shrimp (Palaemonetes argentinus) and fish (Silverside, Odontesthes bonariensis). The bioaccumulation factor (BAF) was calculated for the organisms, and it was determined that the elements analyzed undergo bioaccumulation, especially in organisms such as plankton. The invertebrates were characterized by the highest BAF for Cu and Zn in both seasons, As (DS), and Cd and Hg (WS). The fish muscle was characterized by the highest BAF for Se (WS), Ag and Hg (DS). On the other hand, a significant decrease in Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd and U concentrations through the analyzed trophic web during both seasons was observed. Moreover, a significant increase in Hg levels was observed with increasing trophic levels in the DS, indicating its biomagnification. Despite the increasing impact of metals, As and Se pollution in the studied area due to urban growth and agricultural and livestock activities, no previous study has focused on the behavior and relationships of these pollutants with the biotic and abiotic components of this aquatic reservoir. We expect that these findings may be used for providing directions or guidance for future monitoring and environmental protection policies.

Differential biochemical responses to metal/metalloid accumulation in organs of an edible fish (Centropomus parallelus) from Neotropical estuaries.

Metal/metalloid accumulation in fish organs elicits biochemical responses indicating the overall fish and environmental health status. This study evaluated the bioaccumulation of metals and metalloid in relation to a suite of biochemical biomarkers (superoxide dismutase, catalase, glutathione-S-transferase, Na+/K+-ATPase, H+-ATPase, acetylcholinesterase activities and the levels of glutathione, metallothionein, lipid peroxidation and oxidized protein) in different organs of fish, Centropomus parallelus, in Vitória Bay and Santa Cruz estuaries (State of Espírito Santo, Brazil) with distinct contamination levels. Metal and metalloid concentrations differ in each organ and were significantly higher in winter than in summer. Chemometric evaluation performed between metal/metalloid accumulation and the biomarkers revealed a complex scenario in which the biomarker responses depend on both metal accumulation and organ/tissue sensitivity. The metal levels in gills indicate fish contamination mainly via water and the low sensitivity of this organ to most metals. Biomarker responses suggested that the metal elimination pathway is through the gills and kidney. The hepatopancreas and kidneys were the most important detoxification organs while muscle was the less reactive tissue. In general, the finding suggested that, C. parallelus is partly able to tolerate such metal contamination. However, it is emphasized that the biomarker responses imply an energetic cost and may affect the growth rate and reproduction. Given the ecological and economic importance of C. parallelus, the level of toxic metals/metalloids in juvenile fish is an important early-warning for the maintenance, conservation and commercial use of this species.

Phytofiltration of As3+, As5+, and Hg by the aquatic macrophyte Potamogeton pusillus L, and its potential use in the treatment of wastewater.

The aim of this paper was to investigate the capacity of the aquatic macrophyte Potamogeton pusillus to remove As3+, As5+, and Hg from aqueous solutions. The plants were exposed to 0 mg.L-1, 0.1 mg.L-1, 0.5 mg.L-1, 1 mg.L-1, or 2 mg.L-1 of As3+, As5+, and Hg for 20 days. The results obtained for the individual removal of As3+, As5+, and Hg from water solutions, together with their accumulation in P. pusillus, indicate that this plant can be effectively used for the removal of Hg and of moderate concentrations of As3+ or As5+ (0.1 mg.L-1) from aquatic systems. Roots and leaves accumulated the highest amount of As when the plant was exposed to As5+, but when it was exposed to As3+, the root accumulated the highest amount of As, and the leaves, the highest amount of Hg. When compared to other aquatic plants species, the results showed that P. pusillus demonstrated a higher Hg accumulation (2465 ± 293 µg.g-1) when the transfer coefficient was 40,580 ± 3762 L.kg -1, showing the great potential of this macrophyte for phytoremediation of water contaminated with Hg. To the extent of our knowledge, this is the first report on bioaccumulation of As3+, As5+, and Hg by P. pusillus.

Potential human health risks from metals and As via Odontesthes bonariensis consumption and ecological risk assessments in a eutrophic lake.

The concentration of Al, Cr, Fe, Mn, Ni, Cu, Zn, Hg, Sr, Mo, Ag, Cd, Pb and As was analyzed in water, sediment, and muscle of Odontesthes bonariensis from the eutrophic San Roque Lake (Córdoba-Argentina). The monitoring campaign was performed during the wet, dry and intermediate season. The concentration of Cr, Fe, Pb, Zn, Al and Cd in water exceeded the limits considered as hazardous for aquatic life. The highest metal concentrations were observed in sediment, intermediate concentrations, in fish muscle, and the lowest in water, with the exception of Cr, Zn, As and Hg, which were the highest in fish muscle. Potential ecological risk analysis of heavy metal concentrations in sediment indicated that the San Roque Lake posed a low ecological risk in all sampling periods. The target hazard quotients (THQs) and carcinogenic risk (CR) for individual metals showed that As in muscle was particularly hazardous, posing a potential risk for fishermen and the general population during all sampling periods. Hg poses a potential risk for fishermen only in the intermediate season. It is important to highlight that none of these two elements exceeded the limits considered as hazardous for aquatic life in water and sediment. This result proves the importance of performing measurements of contaminants, in both abiotic and biotic compartments, to assess the quality of food resources. These results suggest that the consumption of this fish species from this reservoir is not completely safe for human health.

Selective and eco-friendly procedures for the synthesis of benzimidazole derivatives. The role of the Er(OTf)3 catalyst in the reaction selectivity.

An improved and greener protocol for the synthesis of benzimidazole derivatives, starting from o-phenylenediamine, with different aldehydes is reported. Double-condensation products were selectively obtained when Er(OTf)3 was used as the catalyst in the presence of electron-rich aldehydes. Conversely, the formation of mono-condensation products was the preferred path in absence of this catalyst. One of the major advantages of these reactions was the formation of a single product, avoiding extensive isolation and purification of products, which is frequently associated with these reactions. Theoretical calculations helped to understand the different reactivity established for these reactions. Thus, we found that the charge density on the oxygen of the carbonyl group has a significant impact on the reaction pathway. For instance, electron-rich aldehydes better coordinate to the catalyst, which favours the addition of the amine group to the carbonyl group, therefore facilitating the formation of double-condensation products. Reactions with aliphatic or aromatic aldehydes were possible, without using organic solvents and in a one-pot procedure with short reaction time (2-5 min), affording single products in excellent yields (75-99%). This convenient and eco-friendly methodology offers numerous benefits with respect to other protocols reported for similar compounds.

Evaluating antibiotic occurrence, degradation, and environmental risks in poultry litter within Argentina's agricultural hub.

This study explores the relationship between poultry farming's antibiotic administration practices and residual antibiotic levels in the litter before its application onto agricultural soils. Twenty-three antibiotics were performed across 19 Argentinean farms representing diverse antibiotic management practices. Analysis revealed up to 20 antibiotics from eight chemical classes in poultry litter samples, with tylosin, enrofloxacin, and salinomycin being the most relevant drugs. Farms with restricted antibiotic use in feed exhibited lower residual concentrations. A self-heating treatment was tested to reduce litter antibiotic levels. Although a 60 % reduction of antibiotics was found after treatment, prevalent compounds persisted at residual levels. Regulatory measures and comprehensive litter treatments pre-application are crucial to mitigate environmental risks. This is the first study that provides insight on the occurrence of >20 drugs in real poultry production scenarios from Latin America and demonstrates how relatively simple treatments can be readily applied to decrease the associated environmental risks.

Effect of acute exposure to settleable atmospheric particulate matter emitted by the steel industry on hematology and innate immunity of fat snook (Centropomus parallelus).

The steel industry is a significant worldwide source of atmospheric particulate matter (PM). Part of PM may settle (SePM) and deposit metal/metalloid and metallic nanoparticles in aquatic ecosystems. However, such an air-to-water cross-contamination is not observed by most monitoring agencies. The region of Vitoria City is the main location of iron processing for exports in Brazil, and it has rivers, estuaries, and coastal areas affected by SePM. We have evaluated the effects of SePM on a local representative fish species, the fat snook, Centropomus parallelus. After acclimation, 48 fishes (61.67 ± 27.83 g) were individually exposed for 96 h to diverse levels of SePM (0.0, 0.01, 0.1 and 1 g/L-1). The presence of metals in the blood and several blood biomarkers were analyzed to evaluate the impact of SePM on stress signaling, blood oxygen transport capacity, and innate immune activity. Metal bioaccumulation was measured from blood in two separately analyzed compartments: intracellular (erythrocytes plus white blood cells) and extracellular (plasma). The major metals present at all contamination levels in both compartments were Fe and Zn, followed by Al and Cu, plus traces of 'Emerging metals': Ba, Ce, La, Rb, Se, Sr, and Ti. Emerging metals refer to those that have recently been identified in water as contaminants, encompassing rare earth elements and critical technology elements, as documented in previous studies (See REEs and TCEs in Cobelo-García et al., 2015; Batley et al., 2022). Multivariate analysis revealed that SePM had strong, dose-dependent correlations with all biomarker groups and indicated that blood oxygen-carrying capacity had the highest contamination responsiveness. Metal contamination also increased cortisol and blood glucose levels, attesting to increased stress signaling, and had a negative effect on innate immune activity. Knowledge of the risks related to SePM contamination remains rudimentary. However, the fact that there was metal bioaccumulation, causing impairment of fundamental physiological and cellular processes in this ecologically relevant fish species, consumed by the local human population, highlights the pressing need for further monitoring and eventual control of SePM contamination.

Integrating chemical and biological data by chemometrics to evaluate detoxification responses of a neotropical bivalve to metal and metalloid contamination.

Mangroves represent a challenge in monitoring studies due to their physical and chemical conditions under constant marine and anthropogenic influences. This study investigated metals/metalloids whole-body bioaccumulation (soft tissues) and the risk associated with their uptake, biochemical and morphological detoxification processes in gills and metals/metalloids immobilisation in shells of the neotropical sentinel oyster Crassostrea rhizophorae from two Brazilian estuarine sites. Biochemical and morphological responses indicated three main mechanisms: (1) catalase, superoxide dismutase and glutathione played important roles as the first defence against reactive oxygen species; (2) antioxidant capacity against peroxyl radicals, glutathione S-transferase, metallothionein prevent protein damage and (3) metals/metalloids sequestration into oyster shells as a mechanism of oyster detoxification. However, the estimated daily intake, target hazard quotient, and hazard index showed that the human consumption of oysters would not represent a human health risk. Among 14 analysed metals/metalloids, chemometrics indicate that Mn, As, Pb, Zn and Fe overload the antioxidant system leading to morphological alterations in gills. Overall, results indicated cellular vacuolization and increases in mucous cell density as defence mechanisms to prevent metals/metalloids accumulation and the reduction in gill cilia; these have long-term implications in respiration and feeding and, consequently, for growth and development. The integration of data from different sites and environmental conditions using chemometrics highlights the main biological patterns of detoxification from a neotropical estuarine bivalve, indicating the way in which species can cope with metals/metalloids contamination and its ecological consequences.

Comparative metabolite fingerprinting of chia, flax and sesame seeds using LC-MS untargeted metabolomics.

Chia, flax, and sesame seeds are well known for their nutritional quality and are commonly included in bakery products. So far, the development of methods to verify their presence and authenticity in foods is a requisite and a raised need. In this work we applied untargeted metabolomics to propose authenticity markers. Seeds were analyzed by HPLC-MS/MS and 9938 features in negative mode and 9044 in positive mode were obtained by Mzmine. After isotopes grouping, alignment, gap-filling, filtering adducts, and normalization, PCA was applied to explore the dataset and recognize pre-existent classification patterns. OPLS-DA analysis and S-Plots were used as supervised methods. Twenty-five molecules (12 in negative mode and 13 in positive mode) were selected as discriminant for the three seeds, polyphenols and lignans were identified among them. To the best of our knowledge, this is the first approach using non-target HPLC-MS/MS for the authentication of chia, flax and sesame seeds.

Effect of geographical location, processing and simulated digestion on antioxidant characteristics of quince (Cydonia oblonga).

Quince fruit (Cydonia oblonga Miller) is an important source of bioactive compounds, especially of phenolic compounds, that's why it is considered a good source of antioxidants. However, it is known that the antioxidant characteristics and the beneficial effect of foods are affected by the variety, geographical origin, processing and gastrointestinal digestion. In this work, the effects of the geographical origin, processing, and simulated digestion of quince jam on its antioxidant characteristics were studied. Phenolic composition and antioxidant capacity were determined in quince fruit and jam from four different locations in San Juan, Argentina. The results showed that quince fruit samples from St. Lucia had the highest total phenolic content (5.13 mg GAE/g; p < 0.05) and in vitro antioxidant capacity measured by ferric-reducing antioxidant power assay (FRAP) and radical-scavenging capacity assay (DPPH· and ABTS·+ ). With regard to quince jam, a positive effect was observed on its antioxidant characteristics after processing. Twenty-one phenolics were detected in jam, being most of them derivatives of hydroxycinnamic acids (eg. 5-caffeoylquinic acid; 4-caffeoylquinic acid and quinic acid). Studies on stability and bioaccessibility of quince phenolics showed that less than 25% of the initial phenolics in jam were detected after digestion being quinic acid and hydroxycinnamic acids the most resistant. The in vitro antioxidant capacity showed, in general, a similar trend to the phenolics content throughout the digestion process. The results obtained showed that the antioxidant activity of quince and jam is related to the type and amount of phenolics in the samples, which depends on the geographical origin, processing, and gastrointestinal digestion. These variables are not always taken into account when studying the probable antioxidant activity of food, even though they should be considered for a complete nutritional evaluation of a food.

Novel cookie formulation with defatted sesame flour: Evaluation of its technological and sensory properties. Changes in phenolic profile, antioxidant activity, and gut microbiota after simulated gastrointestinal digestion.

Defatted sesame flour (DSF), a coproduct of the sesame oil extraction process, is often discarded despite having high polyphenol content. The aim of this study was to improve the antioxidant properties of cookies with increasing amounts of DSF (5, 10, and 20%) and study its impact on processing and gastrointestinal digestion. Besides, we evaluated the effect of this incorporation on the technological and sensory properties of cookies. The formulation with 10% (SFC10) showed technological quality similar to control, and was the most accepted by consumers. After baking, 13 out of 25 polyphenols from DSF were observed, and only 19% of the initial SFC10 polyphenols would be potentially absorbed after digestion. Besides, the addition of DSF benefits the microbiota composition after colonic fermentation. In conclusion, supplementation with 10% of DSF in cookies improves sensorial acceptance and antioxidant properties, without affecting the technological ones.

Arylated analogues of cypronazole: fungicidal effect and activity on human fibroblasts. Docking analysis and molecular dynamics simulations.

Triadimefon (TDM) and cyproconazole (CPZ) are two triazoles widely used as fungicides. Several azoles were synthesised starting from commercial TDM and CPZ. The compounds were evaluated against phytopathogenic filamentous fungi, including Aspergillus fumigatus (AF), A. niger (AN), A. ustus (AU), A. japonicus (AJ), A. terreus (AT), Fusarium oxysporum and Botrytis cinerea isolated from grapevine in the province of San Juan, Argentina. Three of the synthesised compounds (1-(Biphenyl-4-yloxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)butan-2-one, 1; 2-(Biphenyl-4-yl)-3-cyclopropyl-1-(1H-1,2,4-triazol-1-yl)butan-2-ol, 3; 3-Cyclopropyl-2-(4'-fluorobiphenyl-4-yl)-1-(1H-1,2,4-triazol1-yl)butan-2-ol, 4) presented remarkable in vitro fungicidal properties, with better effects than TDM and CPZ on some of the target fungi. Cytotoxicity was assessed using human lung fibroblasts MRC5. Derivative 1, with IC50 values of 389.4 µM, was less toxic towards MRC-5 human lung fibroblasts than commercial TDM (248.5 µM) and CPZ (267.4 µM). Docking analysis and molecular dynamics simulations suggest that the compounds present the same interaction in the binding pocket of the CYP51B enzyme and with the same amino acids as CPZ. The derivatives investigated could be considered broad-spectrum but with some selectivity towards imperfect fungi.

Identification of chia, flax and sesame seeds authenticity markers by NMR-based untargeted metabolomics and their validation in bakery products containing them.

Chia, flax, and sesame seeds are considered superseeds due to their beneficial nutritional properties, and they are frequently included as functional ingredients in foods. Authenticity markers of these seeds, including bakery products containing them, have been identified by both liquid and gas chromatography coupled to mass spectrometry (LC-MS/MS and GC-MS/MS, respectively) targeted metabolomics. However, there are no reports describing the use of nuclear magnetic resonance (NMR) spectroscopy based metabolomics to identify authenticity markers in either the raw seeds or foods containing them. We herein report the application of an untargeted NMR-based metabolomics workflow to the identification of authenticity markers for the three seeds. Seven markers, belonging to the families of polyphenols and cyanogenic glycosides, allowed good differentiation of the raw materials. Validation in cookies containing different seed percentages showed that two markers resisted the processing stage, making them feasible authenticity markers for the food trade.

Metallic nanoparticle contamination from environmental atmospheric particulate matter in the last slab of the trophic chain: Nanocrystallography, subcellular localization and toxicity effects.

Atmospheric particulate material (PM) from mining and steel industries comprises several metallic contaminants. PM10 samples collected in a Brazilian region with a recognized influence of the steel and iron pelletizing industries were used to investigate metallic nanoparticle incorporation into human fibroblast cells (MRC-5). MRC-5 cells were exposed to 0 (control, ultrapure water), 2.5, 5, 10, 20 and 40 µg PM10 mL-1, for 24 h. Cytotoxic and genotoxic dose-response effects were observed on lysosome and DNA structure, and concentrations high as 20 and 40 µg PM10 mL-1 induced elevated cell death. Ultrastructure analyses showed aluminosilicate, iron, and the emerging metallic contaminants titanium, bismuth, and cerium nanoparticles were incorporated into lung cells, in which the nanocrystallography analysis indicated the bismuth as Bi2O3. All internalized metallic nanoparticles were free and unbound in the cytoplasm and nucleus thereby indicating bioavailability and potential interaction to biological processes and cellular structures. Pearson's correlation analysis showed Fe, Ni, Al, Cr, Pb and Hg as the main cytotoxic elements which are associated with the stainless steel production. The presence of internalized nanoparticles in human lung cells exposed to environmental atmospheric matter highlights the need for a greater effort by regulatory agencies to understand their potential damage and hence the need for future regulation, especially of emerging metallic contaminants.

Settleable atmospheric particulate matter induces stress and affects the oxygen-carrying capacity and innate immunity in Nile tilapia (Oreochromis niloticus).

Steel industry emissions of atmospheric particulate matter are responsible for air to water cross-contamination, which deposits metal/metalloid contaminants in aquatic ecosystems. This source of contamination has not been considered in most of the environmental monitoring protocols. Settleable atmospheric particulate matter (SePM) collected in an area of steel industry influence was used to analyze the sublethal effects on the hematological and innate immunological variables in Nile tilapia (Oreochromis niloticus) after short-term exposure (96 h). Blood samples were analyzed to evaluate the oxygen-carrying transport capacity, innate immune activity and stress biomarkers after exposure to ecologically relevant concentration of SePM. The exposure reduced blood oxygen-carrying capacity by lessening hematocrit, hemoglobin, erythrocyte, and mean corpuscular hemoglobin concentration. Compensatory increments in mean corpuscular volume and mean corpuscular hemoglobin have also been observed. The contaminant impacted the immune system by reducing the number of leukocytes, thrombocytes, and monocytes, total plasma protein, leukocyte respiratory activity, and by increasing lysozyme concentration. Furthermore, the contaminant caused endocrine stress response, raising plasma cortisol and glucose. Therefore, the alterations caused by SePM threatened the capacity of sustaining aerobic metabolism, impaired the immune system, and changed the energy allocation due to both stress response and immune effect. This may have important implications for the impact of SePM on aquatic ecosystems. Future investigations should assess SePM impact on general physiology and aerobic performance, especially to face common ecological challenges such as hypoxia and sustained swimming. These results point out the need to develop proper protocols to address the air-to-water cross-contamination risks by iron ore processing industries.

Melatonin levels, determined by LC-ESI-MS/MS, fluctuate during the day/night cycle in Vitis vinifera cv Malbec: evidence of its antioxidant role in fruits.

The identification of melatonin in plants has inspired new investigations to understand its biological function and which endogenous and external factors control its levels in these organisms. Owing to the therapeutical and nutraceutical properties of melatonin, it should be important to develop reliable analytical methods for its quantification in vegetal matrices containing this indoleamine, such as grape and wine. The main objectives of the present study were to test whether melatonin levels fluctuate during the day in berry skins of Vitis vinifera L. cv Malbec, thereby possibly relating its abundance to its putative antioxidant function, to determine whether daylight reaching clusters negatively controls melatonin levels, and to evaluate whether total polyphenols and anthocyanins also change through a 24-hr period. Grapes were harvested throughout the day/night to determine the moment when high levels of these components are present in grapes. The presence of melatonin in grapes was evaluated by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry. It is shown for the first time that melatonin levels fluctuate during the day/night cycle in plants grown under field conditions in a fruit organ of the species Vitis vinifera. We also determined that the diurnal decay of melatonin in berry skins is induced by sunlight, because covered bunches retained higher melatonin levels than exposed ones, thus explaining at least part of the basis of its daily fluctuation. Evidence of melatonin's antioxidant role in grapes is also suggested by monitoring malondialdehyde levels during the day.

Atmospheric particulate matter from an industrial area as a source of metal nanoparticle contamination in aquatic ecosystems.

Air pollution legislation and control worldwide is based on the size of particulate matter (PM) to evaluate the effects on environmental and human health, in which the small diameter particles are considered more dangerous than larger sizes. This study investigates the composition, stability, size and dispersion of atmospheric settleable particulate matter (SePM) in an aqueous system. We aimed to interrogate the changes in the physical properties and characteristics that can contribute to increased metal uptake by aquatic biota. Samples collected in an area influenced by the steel and iron industry were separated into 8 fractions (425 to ≤10 µm) and analysed physically and chemically. Results from ICP-MS and X-ray showed that the PM composition was mainly hematite with 80% of Fe, followed by Al, Mn and Ti. Among 27 elements analysed we found 19 metals, showing emerging metallic contaminants such as Y, Zr, Sn, La, Ba and Bi. Scanning electron microscopy (SEM) showed that SePM fractions are formed by an agglomeration of nanoparticles. Furthermore, dynamic light scattering (DLS), zeta potential and nanoparticle tracking analysis (NTA) demonstrated that SPM were dissociated in water, forming nanoparticles smaller than 200 nm, which can also contribute to water pollution. This study highlights that SePM contamination may be substantially higher than expected under that allowed in atmospheric regulatory frameworks, thereby extending their negative effect to water bodies upon settling, which is an underexplored area of our knowledge. We therefore provide important insights for future investigations on safety regulations involving SePM in the environment, indicating the need to revise the role of SePM, not solely associated with air pollution but also considering their deleterious effects on water resources.