An integrated approach for trace detection of pollutants in water using polyelectrolyte functionalized magneto-plasmonic nanosorbents

Resistance of pathogenic micro-organisms to conventional antibiotics is an essential issue for public health. The presence of such pharmaceuticals in aquatic ecosystems has been of major concern for which remediation and ultra-sensitive monitoring methods have been proposed. A less explored strategy involves the application of multifunctional nanosorbents for the uptake and subsequent detection of vestigial contaminants. In this study, colloidal nanoparticles (NPs) of iron oxide and gold were encapsulated in multi-layers of a charged polyelectrolyte (PEI: polyethyleneimine), envisaging the effective capture of tetracycline (TC) and its subsequent detection by Surface Enhanced Raman Scattering (SERS). Adsorption studies were performed by varying operational parameters, such as the solution pH and contact time, in order to evaluate the performance of the nanosorbents for the uptake of TC from water. While the magnetic nanosorbents with an external PEI layer (Fe3O4@PEI and Fe3O4@PEI-Au@PEI particles) have shown better uptake efficiency for TC, these materials showed less SERS sensitivity than the Fe3O4@PEI- Au nanosorbents, whose SERS sensitivity for TC in water has reached the limit of detection of 10 nM. Thus, this study highlights the potential of such magneto-plasmonic nanosorbents as multi-functional platforms for targeting specific contaminants in water, by taking into consideration both functionalities investigated: the removal by adsorption and the SERS detection across the nanosorbents' surfaces.publishe

Comparison of iodine content in dairy products and non-dairy beverages consumed in Portugal

Os lacticínios per tencem ao grupo de alimentos com maior teor de iodo. Atualmente, cada vez mais a população por tuguesa está a substituir os lacticínios por bebidas vegetais. Como estas bebidas têm geralmente teores de iodo baixo, leva-nos a uma preocupação acrescida sobre o impacto desta popularidade das bebidas vegetais nas necessidades de iodo nos consumidores. O iodo é um micronutriente essencial para a síntese das hormonas da tireoide, presente em pequenas quantidades no corpo humano. O principal objetivo deste trabalho foi a determinação de iodo em lacticínios e bebidas vegetais consumidas em Por tugal. A metodologia escolhida para a quantificação deste nutriente foi a espectrometria de massa acoplada a plasma indutivo (ICP-MS) precedida por extração em meio básico com placa de aquecimento de grafite. Foram analisadas 41 amostras, 15 leites, 20 iogur tes e 6 bebidas vegetais comercializadas por marcas de grande aceitação pela população por tuguesa. Verificou-se que os iogur tes apresentavam maiores concentrações de iodo, seguido do leite e por fim, as bebidas vegetais. Estas apresentaram na sua maioria valores inferiores ao limite de quantificação. Estes resultados levam-nos a concluir que as populações com dietas restritas em lacticínios (intolerância à lactose, alergia à proteína do leite ou vegans) poderão ter um risco acrescido de uma ingestão inadequada em iodo.Dair y products belong to the food group with higher iodine content. Nowadays, the Por tuguese population is increasingly replacing dair y products for non-dair y beverages. As these beverages are generally low in iodine content, it leads to an impact on iodine status in consumers due to an increased popularity of non-dair y beverages. Iodine is an essential micronutrient for the synthesis of thyroid hormones, present in small amounts in the human body. The main objective of this work was the determination of iodine in dair y products and non-dair y beverages consumed in Por tugal. The methodology for the quantification of this nutrient was inductively coupled plasma mass spectrometr y (ICP-MS) preceded by basic ex traction in graphite heating block. We analysed 41 samples, 15 milks, 20 yoghur ts and 6 non-dair y beverages marketed by brands of great acceptance by the Portuguese population. Yoghur ts had higher iodine concentrations, followed by milk and finally non-dair y beverages. Most of non-dair y beverages presented values below the limit of quantification. Therefore, populations with restricted diets in dair y products (lactose intolerance, milk protein allergy or vegans) may lead to an inadequate intake of iodine.info:eu-repo/semantics/publishedVersio

Colloidal dendritic nanostructures of gold and silver for SERS analysis of water pollutants

Surface-Enhanced Raman Scattering (SERS) using colloidal metal (Ag, Au) nanoparticles has been regarded as a powerful method for detecting organic pollutants at vestigial levels. Although less investi- gated, the controlled synthesis of binary nanostructures comprising two metals provides an alternative route to SERS platforms with tuned surface plasmon resonances. Here, we demonstrate that the use of dendrimers allows the formation of distinct combinations of Ag:Au nanostructures that are composed of smaller metal nanocrystals. Our research highlights the role of the dendrimer macromolecules as a multipurpose ligand in the generation of such hybrid nanostructure, including as a reducing agent, an effective long-term colloidal stabilizer and as a molecular glue for interconnecting the primary metal nanocrystals. Noteworthy, the dendrimer-based Ag:Au hybrid nanostructures are more SERS sensitive as compared to the corresponding colloidal blends or to the single-phase metals, as revealed by using molecular pesticides as analytes in spiked water samples. We suggest that the high SERS sensitivity of the hybrid nanostructures is due to interparticle plasmonic coupling occurring between the primary metal nanoparticle aggregates, whose arrangement is templated by the presence of the dendrimer macromolecules.publishe

Dendrimer Stabilized Nanoalloys for Ink-Jet Printing of Surface-Enhanced Raman Scattering Substrates

Research on paper substrates prepared by inkjet deposition of metal nanoparticles for sensing applications has become a hot topic in recent years; however, the design of such substrates based on the deposition of alloy nanoparticles remains less explored. Herein, we report for the first time the inkjet printing of dendrimer-stabilized colloidal metal nanoalloys for the preparation of paper substrates for surface-enhanced Raman scattering (SERS) spectroscopy. To this end, nanoassemblies containing variable molar ratios of Au:Ag were prepared in the presence of poly(amidoamine) dendrimer (PAMAM), resulting in plasmonic properties that depend on the chemical composition of the final materials. The dendrimer-stabilized Au:Ag:PAMAM colloids exhibit high colloidal stability, making them suitable for the preparation of inks for long-term use in inkjet printing of paper substrates. Moreover, the pre-treatment of paper with a polystyrene (PS) aqueous emulsion resulted in hydrophobic substrates with improved SERS sensitivity, as illustrated in the analytical detection of tetramethylthiuram disulfide (thiram pesticide) dissolved in aqueous solutions. We suggest that the interactions established between the two polymers (PAMAM and PS) in an interface region over the cellulosic fibres, resulted in more exposed metallic surfaces for the adsorption of the analyte molecules. The resulting hydrophobic substrates show long-term plasmonic stability with high SERS signal retention for at least ninety days.publishe

Plastic waste use as aggregate and binder modifier in open-graded asphalts

Road pavements are very important infrastructures for the Society, but they can cause serious environmental impacts during construction, operation and rehabilitation phases. Thus, it is essential to develop surface paving solutions that promote not only the durability but also a comfortable and safe use. In fact, this work aims to study the properties of new opengraded mixtures for surface layers produced with plastic wastes. First, HDPE and EVA wastes were used as bitumen modifiers, and then another plastic waste (PEX) replaced part of the aggregates. After studying the modified binders, the open-graded mixtures were designed, and then they were tested concerning their particle loss, rutting resistance, surface texture and damping effect. It was concluded that both ways of using the plastic wastes can improve the mechanical and functional properties of the open-graded mixtures related to the pavement performance.ERDF funds through the Operational Competitiveness Program – COMPETE and the National funds by FCT – Portuguese Foundation for Science and Technology in the scope of PLASTIROADS Project FCOMP-01-0124-FEDER-020335 (PTDC/ECM/119179/2010)

Tree canopy enhances Collembola functional richness and diversity across typical habitats of the Gorongosa National Park (Mozambique)

ABSTRACT: The role of tree canopies in protecting soil functional diversity is essential for ecosystems threatened by the longer lasting periods of drought, which are predicted to increase in the southern afro-tropical region. Nonetheless, biodiversity inventories of soil mesofauna are scarce in afro-tropical ecosystems, even in emblematic and well-studied protected areas, such as the Gorongosa National Park (GNP). Understanding the interrelationships between tree canopies and soil fauna functional diversity can provide insightful information for future adaptive management to protect wildlife and ecosystem services in the GNP, in the context of climate change. Here we assessed collembolan functional type richness and functional diversity in the dry period and during the rainfall across major GNP habitat types: miombo forests, mixed forests, and open savanna/floodplains. Besides the significant positive influence of rainfall, habitat types also influenced functional type’ richness and diversity of collembolan life-forms. Environmental gradients across habitat types, namely the area of tree canopy cover and its indirect effect on soil local conditions (pH and nutrient availability), explained collembolan functional parameters. Calcium concentrations and soil alkalinity significantly enhanced collembolan functional type richness and functional diversity, respectively. Collembola survival across GNP habitats depended on the canopy buffering in the dry sampling period. These results highlight the key role of tree canopies in creating suitable microhabitat conditions supporting soil functional diversity and the sustainability of soil processes and ecosystem services in GNP.info:eu-repo/semantics/publishedVersio

Phosphoprotein Phosphatase 1 isoforms alpha and gamma respond differently to prodigiosin treatment and present alternative kinase targets in melanoma cells

Reversible protein phosphorylation is a central regulatory mechanism of cell function. Deregulation of the balanced actions of protein kinases and phosphatases has been frequently associated with several pathological conditions, including cancer. Many studies have already addressed the role of protein kinases misregulation in cancer. However, much less is known about protein phosphatases influence. Phosphoprotein Phosphatase 1 (PPP1) is one of the major serine/threonine protein phosphatases who has three catalytic isoforms: PPP1CA, PPP1CB, and PPP1CC. Its function is achieved by binding to regulatory subunits, known as PPP1-interacting proteins (PIPs), which may prefer a catalytic isoform. Also, some inhibitors/enhancers may exhibit isoform specificity. Here we show that, prodigiosin (PG), a molecule with anticancer properties, promotes the formation of PPP1CA-AKT complex and not of PPP1CC-MAPK complex. Both, AKT and MAPK, are wellknown PIPs from two pathways that crosstalk and regulate melanoma cells survival. In addition, the analysis performed using surface plasmon resonance (SPR) technology indicates that PPP1 interacts with obatoclax (OBX), a drug that belongs to the same family of PG. Overall, these results suggest that PG might, at least in part, act through PPP1C/PIPs. Also, this study is pioneer in demonstrating PPP1 isoform-specific modulation by small molecules.publishe

TCTEX1D4, a novel protein phosphatase 1 interactor: connecting the phosphatase to the microtubule network

Reversible phosphorylation plays an important role as a mechanism of intracellular control in eukaryotes. PPP1, a major eukaryotic Ser/Thr-protein phosphatase, acquires its specificity by interacting with different protein regulators, also known as PPP1 interacting proteins (PIPs). In the present work we characterized a physiologically relevant PIP in testis. Using a yeast two-hybrid screen with a human testis cDNA library, we identified a novel PIP of PPP1CC2 isoform, the T-complex testis expressed protein 1 domain containing 4 (TCTEX1D4) that has recently been described as a Tctex1 dynein light chain family member. The overlay assays confirm that TCTEX1D4 interacts with the different spliced isoforms of PPP1CC. Also, the binding domain occurs in the N-terminus, where a consensus PPP1 binding motif (PPP1BM) RVSF is present. The distribution of TCTEX1D4 in testis suggests its involvement in distinct functions, such as TGFβ signaling at the blood-testis barrier and acrosome cap formation. Immunofluorescence in human ejaculated sperm shows that TCTEX1D4 is present in the flagellum and in the acrosome region of the head. Moreover, TCTEX1D4 and PPP1 co-localize in the microtubule organizing center (MTOC) and microtubules in cell cultures. Importantly, the TCTEX1D4 PPP1BM seems to be relevant for complex formation, for PPP1 retention in the MTOC and movement along microtubules. These novel results open new avenues to possible roles of this dynein, together with PPP1. In essence TCTEX1D4/PPP1C complex appears to be involved in microtubule dynamics, sperm motility, acrosome reaction and in the regulation of the blood-testis barrier

Iodination of phenols in water using easy to handle amine-iodine complexes

The reaction between iodo and N-methyl-piperazine or thiomorpholine in water, in the presence of KI, led to the formation of stable and easy to handle amine-iodine complexes, as the complex morpholine-iodo previously reported in the literature. However, the complex obtained using N,N-tetrametylethylenediamine proved less stable, while no complex was formed when piperidine was used as base. These results show that the presence of a second heteroatom in the structure of amines is of fundamental importance for the formation and stability of these complexes. In this work we describe, for the first time, the use of complexes morpholine-iodo, N-methyl-piperazine-iodo and thiomorpholine-iodo as iodinating reagents of several substituted phenols, leading to iodinated products in good to excellent yields

An intriguing shift occurs in the novel protein phosphatase 1 binding partner, TCTEX1D4: evidence of positive selection in a pika model

T-complex testis expressed protein 1 domain containing 4 (TCTEX1D4) contains the canonical phosphoprotein phosphatase 1 (PPP1) binding motif, composed by the amino acid sequence RVSF. We identified and validated the binding of TCTEX1D4 to PPP1 and demonstrated that indeed this protein is a novel PPP1 interacting protein. Analyses of twenty-one mammalian species available in public databases and seven Lagomorpha sequences obtained in this work showed that the PPP1 binding motif 90RVSF93 is present in all of them and is flanked by a palindromic sequence, PLGS, except in three species of pikas (Ochotona princeps, O. dauurica and O. pusilla). Furthermore, for the Ochotona species an extra glycosylation site, motif 96NLS98, and the loss of the palindromic sequence were observed. Comparison with other lagomorphs suggests that this event happened before the Ochotona radiation. The dN/dS for the sequence region comprising the PPP1 binding motif and the flanking palindrome highly supports the hypothesis that for Ochotona species this region has been evolving under positive selection. In addition, mutational screening shows that the ability of pikas TCTEX1D4 to bind to PPP1 is maintained, although the PPP1 binding motif is disrupted, and the N- and C-terminal surrounding residues are also abrogated. These observations suggest pika as an ideal model to study novel PPP1 complexes regulatory mechanisms