Gestão de leguminosas anuais de porte erecto como sideração em olival biológico

Em olival conduzido em modo de produção biológico, conseguir manter as árvores num estado nutritivo azotado minimamente aceitável é um tópico de grande relevância. Basicamente, os produtores recorrem a fertilizantes orgânicos ou a produtos para aplicação foliar, tornando a fertilização por vezes excessivamente onerosa e nem sempre suficientemente eficaz. A sideração com leguminosas anuais de porte erecto, em particular com tremoceiros, é uma prática ancestral multo utilizada em olival tradicional para restaurar a fertilidade do solo

Instalação de leguminosas anuais de ressementeira natural como cobertos vegetais em olivais de sequeiro

A introdução de cobertos vegetais à base de leguminosas anuais de ressementeira natural em olival de sequeiro apresenta-se como uma forma aparentemente sustentável de gerir o solo, reduzindo o risco de erosão e promovendo a sua fertilidade. Contudo, como na grande maioria dos olivais tradicionais não existem presentemente animais em pastoreio, a persistência dos cobertos, nestes casos, tem de ser conseguida exclusivamente através do corte. Num ensaio de campo que decorre em Suçães, Mirandela, foram semeadas, separadamente e em mistura, onze espécies/cultivares de leguminosas pratenses de precocidade variável. Foi registada a percentagem de emergência, o grau de cobertura do solo, a evolução fenológica e a produção de matéria seca e o azoto contido na biomassa aérea. As percentagens de emergência, desde Outubro de 2009 a Fevereiro de 2011, ultrapassaram 40% para Ornithopus sativus cv. Margurita, Trifolium subterraneum cvs. Dalkeith, Denmark, Nungarin e O. sativus cv, Erica. A emergência de Biserrula pelecinus cv. Mauro foi apenas de 7%. O contributo das leguminosas semeadas para o grau de cobertura do solo em 30 de Março de 2010 variou de 1% em Mauro a 81% em T. subterraneum cv. Seaton Park. Em 13 de Maio, o contributo das leguminosas semeadas para o grau de cobertura era muito elevado, excluindo Mauro, aproximando-se de 100% nos talhões de Seaton Park (100%), T. michelianum cv. Frontier (97%), T. resupinatum L. cv. Prolific (97%), Denmark (97%) e Erica (96%). Nungarin, O. compressus cv. Charano, e Dalkeith foram as mais precoces à maturação. As espécies/cultivares mais precoces produziram menos matéria seca (MS) e acumularam menor quantidade de azoto (N) na biomassa aérea. T. incarnatum cv. Contea produziu 7788 kg MS ha-1 e acumulou 167 kg N ha-1. Nungarin produziu 3924 kg MS ha-1 e acumulou 53 kg N ha-1. Os primeiros resultados indicam que os cobertos vegetais de leguminosas anuais de ressementeira natural fornecem uma boa proteção ao solo desde o primeiro ano de instalação e que as espécies/cultivares mais precoces são mais promissoras para introduzir em olivais de sequeiro por competirem menos pelos recursos hídricos, apesar de produzirem menos biomassa e fixarem menos azoto atmosférico.PTDC-AGR-AAM/098326/200

Current nanotechnology advances in diagnostic biosensors

Current diagnostics present challenges that are imposed by increased life expectancy in the worldwide population. These challenges are related, not only to satisfy the need for higher performance of diagnostic tests, but also to the capacity of creating pointâ ofâ care, wearable, multiplexing and implantable diagnostic platforms that will allow early detection, continuous monitoring and treatment of health conditions in a personalized manner. These health challenges are translated into technological issues that need to be solved with multidisciplinary knowledge. Nanoscience and technology play a fundamental role in the development of miniaturized sensors that are cheap, accurate, sensitive and consume less power. At nanometre scale, these materials possess higher volumeâ toâ surface ratio and display novel properties (composition, charge, reactive sites, physical structure and potential) that are exploited for sensing purposes. These nanomaterials can therefore be integrated into diagnostic sensing platforms allowing the creation of novel technologies that tackle current health challenges. These nanomaterialâ enhanced sensors are extremely diverse, since they use numerous types of materials, nanostructures and detection modes for a multitude of biomarkers. The purpose of this review is to summarize the current stateâ ofâ theâ art of nanomaterialâ enhanced sensors, emphasizing and discussing the diagnostic challenges that are addressed by the different engineering and nanotechnology approaches. This review also aims to identify the drawbacks of nanomaterialâ enhanced sensors, as well as point out future developmental directions.This research was funded by FCT- FUNDAÇÃO PARA A CIÊNCIA E TECNOLOGIA, grant numbers: PTDC/EMD-EMD/31590/2017 and PTDC/BTM-ORG/28168/2017

Characterizing the potential of the non-conventional yeast Saccharomycodes ludwigii UTAD17 in winemaking

Non-Saccharomyces yeasts have received increased attention by researchers and winemakers, due to their particular contributions to the characteristics of wine. In this group, Saccharomycodes ludwigii is one of the less studied species. In the present study, a native S. ludwigii strain, UTAD17 isolated from the Douro wine region was characterized for relevant oenological traits. The genome of UTAD17 was recently sequenced. Its potential use in winemaking was further evaluated by conducting grape-juice fermentations, either in single or in mixed-cultures, with Saccharomyces cerevisiae, following two inoculation strategies (simultaneous and sequential). In a pure culture, S. ludwigii UTAD17 was able to ferment all sugars in a reasonable time without impairing the wine quality, producing low levels of acetic acid and ethyl acetate. The overall effects of S. ludwigii UTAD17 in a mixed-culture fermentation were highly dependent on the inoculation strategy which dictated the dominance of each yeast strain. Wines whose fermentation was governed by S. ludwigii UTAD17 presented low levels of secondary aroma compounds and were chemically distinct from those fermented by S. cerevisiae. Based on these results, a future use of this non-Saccharomyces yeast either in monoculture fermentations or as a co-starter culture with S. cerevisiae for the production of wines with greater expression of the grape varietal character and with flavor diversity could be foreseen. View Full-Textinfo:eu-repo/semantics/publishedVersio

Antibiofilm potential of medicinal plants against Candida spp. oral biofilms: a review

The use of natural products to promote health is as old as human civilization. In recent years, the perception of natural products derived from plants as abundant sources of biologically active compounds has driven their exploitation towards the search for new chemical products that can lead to further pharmaceutical formulations. Candida fungi, being opportunistic pathogens, increase their virulence by acquiring resistance to conventional antimicrobials, triggering diseases, especially in immunosuppressed hosts. They are also pointed to as the main pathogens responsible for most fungal infections of the oral cavity. This increased resistance to conventional synthetic antimicrobials has driven the search for new molecules present in plant extracts, which have been widely explored as alternative agents in the prevention and treatment of infections. This review aims to provide a critical view and scope of the in vitro antimicrobial and antibiofilm activity of several medicinal plants, revealing species with inhibition/reduction effects on the biofilm formed by Candida spp. in the oral cavity. The most promising plant extracts in fighting oral biofilm, given their high capacity to reduce it to low concentrations were the essential oils extracted from Allium sativum L., Cinnamomum zeylanicum Blume. and Cymbopogon citratus (DC) Stapf.The authors wish to acknowledge financial support from the project “AquaValor—Centro de Valorização e Transferência de Tecnologia da Água” (NORTE-01-0246-FEDER-000053), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). The authors are also grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (UIDB/00690/2020); and L. Barros is grateful for her contract through the institutional scientific employment program-contract.info:eu-repo/semantics/publishedVersio

Active neutralizing mats for corrosive chemical storage

Laboratories and industries that handle chemicals are ubiquitously prone to leakages. These may occur in storage rooms, cabinets or even in temporary locations, such as workbenches and shelves. A relevant number of these chemicals are corrosive, thus commercial products already exist to prevent material damage and injuries. One strategy consists of the use of absorbing mats, where few display neutralizing properties, and even less a controlled neutralization. Nevertheless, to the authors’ knowledge, the commercially available neutralizing mats are solely dedicated to neutralizing acid or alkali solutions, never both. Therefore, this work describes the development and proof of a completely novel concept, where a dual component active mat (DCAM) is able to perform a controlled simultaneous neutralization of acid and alkali leakages by using microencapsulated active components. Moreover, its active components comprise food-grade ingredients, embedded in nonwoven polypropylene. The acid neutralizing mats contain sodium carbonate (Na2CO3 ) encapsulated in sodium alginate microcapsules (MC-ASC). Alkali neutralizing mats possess commercial encapsulated citric acid in hydrogenated palm oil (MIRCAP CT 85-H). A DCAM encompasses both MC-ASC and MIRCAP CT 85-H and was able to neutralize solutions up to 10% (v/v) of hydrochloric acid (HCl) and sodium hydroxide (NaOH). The efficacy of the neutralization was assessed by direct titration and using pH strip measurement tests to simulate the leakages. Due to the complexity of neutralization efficacy evaluation based solely on pH value, a thorough conductivity study was performed. DCAM reduced the conductivity of HCl and NaOH (1% and 2% (v/v)) in over 70%. The composites were characterized by scanning electron microscopy (SEM), differential calorimetry (DSC) and thermogravimetric analysis (TGA). The size of MC-ASC microcapsules ranged from 2 µm to 8 µm. Finally, all mat components displayed thermal stability above 150 ◦C

Chitosan micro-membranes with integrated gold nanoparticles as an LSPR-based sensing platform

Currently, there is an increasing need to develop highly sensitive plasmonic sensors able to provide good biocompatibility, flexibility, and optical stability to detect low levels of analytes in biological media. In this study, gold nanoparticles (Au NPs) were dispersed into chitosan membranes by spin coating. It has been demonstrated that these membranes are particularly stable and can be successfully employed as versatile plasmonic platforms for molecular sensing. The optical response of the chitosan/Au NPs interfaces and their capability to sense the medium’s refractive index (RI) changes, either in a liquid or gas media, were investigated by high-resolution localized surface plasmon resonance (HR-LSPR) spectroscopy, as a proof of concept for biosensing applications. The results revealed that the lowest polymer concentration (chitosan (0.5%)/Au-NPs membrane) presented the most suitable plasmonic response. An LSPR band redshift was observed as the RI of the surrounding media was incremented, resulting in a sensitivity value of 28 ± 1 nm/RIU. Furthermore, the plasmonic membrane showed an outstanding performance when tested in gaseous atmospheres, being capable of distinguishing inert gases with only a 10−5 RI unit difference. The potential of chitosan/Au-NPs membranes was confirmed for application in LSPR-based sensing applications, despite the fact that further materials optimization should be performed to enhance sensitivity.This research was sponsored by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UIDB/04650/2020, by the project CO2Plasmon with reference EXPL/CTM-REF/0750/2021 and by the project with reference PTDC/CTM-CTM/2846/2020. Diana I. Meira acknowledges her Ph.D. Scholarship from FCT, with reference SFRH/BD/143262/2019. Manuela Proença acknowledges her Ph.D. Scholarship from FCT, with reference SFRH/BD/137076/2018

Antiproliferative activity of neem leaf extracts obtained by a sequential pressurized liquid extraction

Azadirachta indica A. Juss (neem) extracts have been used in pharmaceutical applications as antitumor agents, due to their terpenes and phenolic compounds. To obtain extracts from neem leaves with potential antiproliferative effect, a sequential process of pressurized liquid extraction was carried out in a fixed bed extractor at 25◦C and 100 bar, using hexane (SH), ethyl acetate (SEA), and ethanol (SE)assolvents. Extractions using only ethanol(EE) was also conducted to compare the characteristics of the fractionated extracts. The results obtained by liquid chromatography-electrospray ionization mass spectrometry suggested a higher concentration of terpenes in the SEA extract in comparison to SH, SE, and EE extracts. Therefore, antiproliferative activity showed that SEA extracts were the most efficient inhibitor to human tumor cells MCF-7, NCI-H460, HeLa, and HepG2. Hepatocellular cells were more resistant to SH, SEA, SE, and EE compared to breast, lung, hepatocellular, and cervical malignant cells. Neem fractioned extracts obtained in the present study seem to be more selective for malignant cells compared to the non-tumor cells.Klebson Silva Santos thanks CAPES (Process: PDSE 99999.003409/15-5) for the financial support during his Ph.D. studies in Portugal. Authors are grateful to CAPES, and FAPITEC (EDITAL CAPES/FAPITEC Nº 11/2016–PROEF/Processo de AUXPE 88881.157437/2017-01) for the financial support. The study was also carried out with financial support from FEDER, under the Partnership Agreement PT2020.info:eu-repo/semantics/publishedVersio