Development of a disposable paper-based potentiometric immunosensor for real-time detection of a foodborne pathogen

This work reports a new paper-based sensing platform and its application in a label-free potentiometric immunosensor for Salmonella typhimurium detection based on the blocking surface principle. A paper-based strip electrode was integrated with a filter paper pad which acted as a reservoir of the internal solution. The design offers a convenient platform for antibody immobilization and sampling, proving also that is a simple and affordable methodology to control an ionic flux through a polymer membrane. Two different immunosensing interfaces were assembled on the developed paper-strip electrode. The simplest interface relied on direct conjugation of the antibody to the polymer membrane and the second one resorted to an intermediate layer of a polyamidoamine dendrimer, with an ethylenediamine core from the fourth generation. Electrochemical impedance spectroscopy was used to assess the successive interface modification steps and the resulting analytical performance of both immunosensors was compared. For such, the potential shift derived from the blocking effect of the ionic flux caused by antigen-antibody conjugation was correlated with the logarithm of the Salmonella typhimurium concentration in the sample. In optimized conditions, a limit of detection of 5 cells mL-1 was achieved. As a proof-of-concept, the proposed method was applied to apple juice samples, demonstrating to be a suitable prototype to be used in real scenarios in useful time (<1 h assay).This work received financial support from the European Union and National Funds(FCT, Fundação para a Ciência e Tecnologia) through projects UID/QUI/50006/2019 and Norte-01-0145-FEDER-000011-RL1–QUALIFOOD. N.F.D Silva is grateful to FCT grant SFRH/BD/112414/2015, financed by POPH–QREN–Tipologia 4.1–FormaçãoAvançada,subsidizedbyFSEandMCTES.info:eu-repo/semantics/publishedVersio

Advances in extraction methods to recover added-value compounds from seaweeds: sustainability and functionality

Seaweeds are a renewable natural source of valuable macro and micronutrients that have attracted the attention of the scientists in the last years. Their medicinal properties were already recognized in the ancient traditional Chinese medicine, but only recently there has been a considerable increase in the study of these organisms in attempts to demonstrate their health benefits. The extraction process and conditions to be used for the obtention of value-added compounds from seaweeds depends mainly on the desired final product. Thermochemical conversion of seaweeds, using high temperatures and solvents (including water), to obtain high-value products with more potential applications continues to be an industrial practice, frequently with adverse impact on the environment and productsâ functionality. However more recently, alternative methods and approaches have been suggested, searching not only to improve the process performance, but also to be less harmful for the environment. A biorefinery approach display a valuable idea of solving economic and environmental drawbacks, enabling less residues production close to the much recommended zero waste system. The aim of this work is to report about the new developed methods of seaweeds extractions and the potential application of the components extracted.This work was funded by the Portuguese Foundation for Science and Technology (FCT) un der the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte. The work was also supported by the Euro pean Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant (MSCA-RISE; FODIAC; 778388). Gabriela Matos is recipient of a PhD fellowship supported by a doctoral advanced training (call NORTE-69-2015-15), funded by the European Social Fund under the scope of Norte2020—Programa Operacional Regional do Norte (NORTE-08-5369-FSE-000036). Sara Pereira and Zlatina Genisheva are supported by the project OH2O (POCI-01-0145-FEDER 029145) funded by FCT and Fundo Europeu de Desenvolvimento Regional (FEDER) under the scope of Programa Operacional de Competividade e Internacionalização (POCI)-COMPETE 2020 and Portugal 2020.info:eu-repo/semantics/publishedVersio

Uma variante do gene WNK4 está associada à osteoporose mas não à hipertensão na população portuguesa

Germline mutations in the WNK4 gene originate Gordon syndrome or pseudohypoaldosteronism type II, a familial form of hypertension with hyperkalemia and hypercalciuria. The WNK4 protein encodes a protein kinase involved in the regulation of various renal ion channels. In order to elucidate the contribution of WNK4 genetic variants to hypertension and/or osteoporosis, we analyzed 271 control individuals and a cohort of 448 hypertensive and 372 osteoporosis patients from the Portuguese population. Ten genetic variants were detected in 4.3% of the population under study, none of which revealed any significant association to the hypertension phenotype. In contrast, a rare missense alteration in a highly conserved arginine residue in exon 17 showed an association to the osteoporosis group. Our data suggest that WNK4 polymorphism rs56116165 is a rare allelic variant of a candidate gene with a biological function in renal calcium homeostasis and thus may contribute to a genetic predisposition to osteoporosis.FC