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Carbon nanotubes are promising materials for biomedical applications like delivery systems and tissue scaffolds. In this paper, magnetic carbon nanotubes (M-CNTs) covered with bovine serum albumin (M-CNTs-BSA) or functionalized with hydrophilic monomers (M-CNTs-HL) were synthesized, characterized, and evaluated concerning their interaction with Caco-2 cells. There is no comparison between these two types of functionalization, and this study aimed to verify their influence on the material's interaction with the cells. Different concentrations of the nanotubes were applied to investigate cytotoxicity, cell metabolism, oxidative stress, apoptosis, and capability to cross biomimetic barriers. The materials showed cytocompatibility up to 100 µg mL-1 and a hemolysis rate below 2 %. Nanotubes' suspensions were allowed to permeate Caco-2 monolayers for up to 8 h under the effect of the magnetic field. Magnetic nanoparticles associated with the nanotubes allowed estimation of permeation through the monolayers, with values ranging from 0.50 to 7.19 and 0.27 to 9.30 × 10-3 µg (equivalent to 0.43 to 6.22 and 0.23 to 9.54 × 10-2 % of the initially estimated mass of magnetic nanoparticles) for cells exposed and non-exposed to the magnets, respectively. Together, these results support that the developed materials are promising for applications in biomedical and biotechnological fields.

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A better understanding of the relative roles of internal climate variability and external contributions, from both natural (solar, volcanic) and anthropogenic greenhouse gas forcing, is important to better project future hydrologic changes. Changes in the evaporative demand play a central role in this context, particularly in tropical areas characterized by high precipitation seasonality, such as the tropical savannah and semi-desertic biomes. Here we present a set of geochemical proxies in speleothems from a well-ventilated cave located in central-eastern Brazil which shows that the evaporative demand is no longer being met by precipitation, leading to a hydrological deficit. A marked change in the hydrologic balance in central-eastern Brazil, caused by a severe warming trend, can be identified, starting in the 1970s. Our findings show that the current aridity has no analog over the last 720 years. A detection and attribution study indicates that this trend is mostly driven by anthropogenic forcing and cannot be explained by natural factors alone. These results reinforce the premise of a severe long-term drought in the subtropics of eastern South America that will likely be further exacerbated in the future given its apparent connection to increased greenhouse gas emissions.

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The aim of this work is to evaluate two quantitative methods, based on the external calibration applied in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis, known as (i) analytical curve and (ii) one-point calibration, using the concept of matrix matching to quantify three potentially toxic elements (PTEs) in wood samples. These can biologically register changes in the abiotic environment and be applied to monitoring climate change or environmental toxicity. In this case, standard sample preparation was evaluated to prepare the standard pellets using Pinus taeda species as a matrix-matching concept. Six pellets of P. taeda, with different Pb, Cd, and Ba concentrations, were prepared to build the analytical curve and one-point calibration strategies. The LA-ICP-MS parameters were optimised for 206Pb, 208Pb, 112Cd, 114Cd, 137Ba, and 138Ba isotope analysis in wood samples. The two calibration strategies provided 74-110% analytical recovery from certified reference materials and similar results to those obtained by ICP-MS through the acid digestion of environmental wood samples from São Paulo City (Brazil). This demonstrated the applicability of the one-point calibration strategy in quantifying PTEs in wood samples, which could be used with environmental analyses. Differences observed between the Ba isotope results obtained via LA-ICP-MS and ICP-MS quantification were related to sampling by LA-ICP-MS and the ICP-MS sample introduction, as well as to laser matrix and transport effects because of the difference between the wood species evaluated.

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BACKGROUND: Nanoparticles (NPs) are currently found in the world in the form of natural colloids and volcanic ash, as well as in anthropogenic sources, such as nanofertilizers; however, in the literature, there is still a lack of toxicological evidence, risk assessment, and regulations about the use and environmental impact of NPs in the agroindustrial system. Therefore, the aim of this work was to evaluate alterations caused by the presence of AgNPs during the development of soybean plants. METHODS: The BRS232 non-transgenic (NT) soybean plant and 8473RR (TRR) and INTACTA RR2 PRO (TIntacta) transgenic soybean plants were irrigated for 18 days under controlled conditions with deionized water (control), AgNPs, and AgNO3. The isotopes 107Ag+, 55Mn+, 57Fe+, 63Cu+, and 64Zn+ were mapped in leaves, using 13C+ as an internal standard (IS), and carried out using a laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) technique with a Nd:YAG (213 nm) laser source in the imagagin mode using the LA-iMageS software and also Mathlab. RESULTS: Leaf images showed a low Ag translocation, indicated by the basal signal of this ion. Additionally, the presence of Ag in the ionic form and as NPs altered the homeostasis of 112Cd+, 64Zn+, 55Mn+, 63Cu+, and 57Fe+ in different ways. Quantitative image analysis was performed for Cu. CONCLUSION: The behavior of TRR and TIntacta plants was different in the presence of ionic silver or AgNPs, confirming that the metabolism of these two plants, despite both being transgenic, are different. Through the images, it was observed that the response of plants was different in the face of the same stress conditions during their development.

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Somatic embryogenesis is an essential technology for high productivity in plant culture, and with the advent of nanotechnology, the synergism between these areas could be the answer to developing concepts involving Agriculture 4.0. This perspective permeates both areas, presenting the opportunities and challenges for the consolidation of ideas involving the application of nanoparticles to micropropagation processes (callus induction, preservation, growing, and modification, among others) and also to the production of byproducts (such as biosynthesis of nanoparticles and production of secondary metabolites). Nanotoxicological aspects are also emphasized as well as up-to-date instrumentation involved in these studies.

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RATIONALE: A viable and accurate method based on high-power ultrasound-assisted microextraction and inductively coupled plasma mass spectrometry was developed to determine metals in human serum from patients with bipolar disorder and schizophrenia. METHODS: A simple and rapid sample preparation method using a cup-horn sonoreactor was developed. The acid concentration of HNO3 (10, 20, and 40% v/v) and HCl (1, 5, 15, and 30% v/v) of the extraction solution, the sonication time (1, 3, 6, and 10 min), and the sonication amplitude (20, 40, 60, and 80%) were evaluated. Cd, Cu, Fe, Li, Pb, and Zn were determined in serum samples from patients with bipolar disorder and schizophrenia, and from healthy controls. Quantitative metal recoveries using the proposed method were compared under the same conditions using an ultrasonic bath, magnetic stirring, and microwave-assisted digestion. RESULTS: Optimum extraction conditions were obtained using HNO3 (40% v/v) + HCl (30% v/v) as the extraction solution with 3 min sonication time and 60% sonication amplitude. Significant differences were observed among the methods compared. On application of the sample preparation method based on high-power ultrasound-assisted microextraction coupled with inductively coupled plasma mass spectrometry, Pb and Cd in all the studied samples were below the limit of detection of our method. Compared with healthy controls, the concentration of Cu, Li, Fe, and Zn was found to be significantly higher for the bipolar disorder group, while these metals and Li were found at a lower level for the group diagnosed with schizophrenia. CONCLUSIONS: Principal component analysis showed a significant separation for the groups studied based on their ionomic profiles after the application of high-power ultrasound-assisted microextraction as a sample preparation strategy.

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RATIONALE: An evaluation of bipolar disorder (BD) and schizophrenia (SCZ) was carried out, from a metallomics point of view, using native conditions, attempting to preserve the interaction between metals and biomolecules. METHOD: For this task, blood serum samples from healthy individuals and patients were compared. In addition, the profiles of metal ions and metalloids involved in the pathologies were quantified, and a comparison was carried out of the protein profile in serum samples of healthy individuals and diseased patients. RESULTS: After optimization and accuracy evaluation of the method, different concentrations of Li, Mg, Mn and Zn were observed in the samples of BD patients and high levels of copper for SCZ patients, indicating an imbalance in the homeostasis of important micronutrients. The treatment, especially with lithium, may be related to competition between metallic ions. BD-related metallobiomolecules were detected, preserving the binding between metal ions and biomolecules, with four fractions detected in the ultraviolet range (280 nm). Four fractions were collected by high-performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC/ICP-MS) and the proteins were identified by liquid chromatography/tandem mass spectrometry (LC/MS/MS). The Ig lambda chain V-IV region Hil, immunoglobulin heavy constant gama 1 (IGHG1) and beta-2-glycoprotein 1 (or ApoH) was identified in SCZ samples, suggesting its relationship with mood disorders. Surprisingly, Protein IGKV2D-28 was identified only in BD samples, opening up new possibilities for studies regarding the role of this protein in BD. CONCLUSIONS: This approach brings new perspectives to the comprehension of mood disorders, highlighting the importance of metallomics science in disease development. This strategy showed an innovative potential for evaluating mood disorders at the proteomic level, making it possible to identify proteins related to mood disorders and BD.

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Although air pollution decreased in some cities that shifted from an industrial to a service-based economy, and vehicular emission regulation became more restrictive, it is still a major risk factor for mortality worldwide. In central São Paulo, Brazil, air quality monitoring stations and tree-ring analyses revealed a decreasing trend in the concentrations of particulate matter and metals. Such trends, however, may not be observed in industrial districts located in the urban periphery, where the usual mobile sources may be combined with local stationary sources. To evaluate environmental pollution in an industrial district in southeastern São Paulo, we assessed its spatial variability, by measuring magnetic properties and concentrations of Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, P, S, Sr, Zn in the bark of 62 trees, and its temporal trends, by measuring Cd, Cu, Ni, Pb, V, Zn in tree rings of three trees. Source apportionment analysis based on tree barks revealed two clusters with high concentrations of metals, one related to vehicular and industrial emissions (Al, Ba, Cu, Fe, Zn) in the east side of the industrial cluster, and the other related to soil resuspension (Cu, Zn, Mn) in its west side. These patterns are also supported by the magnetic properties of bark associated with iron oxides and titanium-iron alloy concentrations. Dendrochemical analyses revealed that only the concentrations of Pb consistently decreased over the last four decades. The concentrations of Cd, Cu, Ni, V, and Zn did not significantly decrease over time, in contrast with their negative trends previously reported in central São Paulo. This combined biomonitoring approach revealed spatial clusters of metal concentration in the vicinity of this industrial cluster and showed that the local population has not benefited from the decreasing polluting metal concentrations in the last decades.

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Although high levels of dissolved arsenic were detected in surface and ground waters of Nhecolândia, a sub-region of the vast Pantanal wetlands in Brazil, the possible sources have not been clearly identified and the potential release from the wetland to the draining rivers has not been investigated. In this study we measured the dissolved As content in all the rivers and small streams that supply the southern Pantanal region, as well as in the two main rivers draining the wetland, i.e., the Cuiaba and Paraguay rivers and tributaries. In addition, Arsenic in surface waters, perched water-table, soils and sediments from 3 experimental sites located in the heart of Nhecolândia were compared. On the one hand, the results show the absence of As contamination in rivers that supply the Pantanal floodplain, as well as a lack of significant release from the floodplain to the main drains. The As contents in the rivers are <2 µg L-1, with variations that depend on the lithology and on the geomorphology at the collection point (uplands or floodplain). On the other hand, they confirm the regional extension of As contamination in Nhecolândia's alkaline waters with some values above 3 mg L-1. Arsenic is mainly in the arsenate form, and increases with the evaporation process estimated from sodium ion concentrations. The pH of soil solution and surface water increases rapidly during evapo-concentration up to values above 9 or 10, preventing adsorption processes on oxides and clay minerals and promoting the retention of dissolved arsenic in solution. Solutions from organic soil horizons show higher As contents in relation to Na, attributed to the formation of ternary complex As-(Fe/Al)-OM. In this alkaline pH range, despite high levels of dissolved As, soil horizons and lake sediments in contact with these waters show As values that correspond to uncontaminated environments.

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Ydj1, a class B J-protein (Hsp40) in yeast, has two zinc finger domains in each monomer and belongs to an important co-chaperone family that plays crucial roles in cells, such as recognizing and binding partially folded proteins and assisting the Hsp70 chaperone family in protein folding. Yeast cells with ydj1 deletion were less efficient at coping with zinc stress than wild-type cells, and site-directed mutagenesis studies that impair or delete the zinc finger region have confirmed the importance of this region to the function of Ydj1; however, little is known about whether the presence of zinc is critical for the function of the protein. To gain insights into the effect of zinc on the structure and function of Ydj1 without having to modify its primary structure, a method was developed and optimized to quantify and remove the zinc from the protein. Recombinant Ydj1 was produced and purified, and its zinc content was determined by ICP-MS. The result showed that two zinc atoms were bound per monomer of protein, a good indicator that all sites were saturated. To optimize the removal of the bound zinc, variations on chelating agent (EDTA, EGTA, 1,10-phenanthroline), chelator concentration, reaction time, pH, and temperature were tested. These procedures had no effect on the overall secondary structure of the protein, since no significant changes in the circular dichroism spectrum were observed. The most significant removal (91 ± 2%, n = 3) of zinc was achieved using 1,10-phenanthroline (1 × 10-3 mol L-1) at 37°C with a pH 8.5 for 24 h. Zinc removal affected the stability of the protein, as observed by a thermal-induced unfolding assay showing that the temperature at the middle of the transition (Tm) decreased from 63 ± 1°C to 60 ± 1°C after Zn extraction. In addition, the effect on the ability of Ydj1 to protect a model protein (luciferase) against aggregation was completely abolished after the Zn removal procedure. The main conclusion is that zinc plays an important role in the stability and activity of Ydj1. Additionally, the results highlight the medical importance of chaperones, as altered zinc homeostasis is implicated in many diseases, such as neurodegenerative disorders.