2,923 research outputs found

    Food mycology : from the fork to the farm

    Get PDF
    Filamentous fungi are ubiquitous in nature and are responsible for producing mycotoxins in agricultural crops. Fungi and mycotoxins are considered generally as being natural and unavoidable [1]. The control and detection of mycotoxins is a continuous process in commodity production. Since mycotoxins can become established and remain within the commodity anywhere throughout the production, storage, transportation and processing chain, there is a need to study all the food chain: from the fork to the farm. The control over the presence of mycotoxins involves several competencies, such as taxonomy skills, ability to evaluate mycotoxins production by fungi, and ability to quantify mycotoxins in commodities. The prevention of mycotoxin formation is achieved by influencing environmental conditions through management of agricultural practices prior to harvest. After harvest, two overriding factors for storage are water activity (aw) and temperature. Control over these parameters may lead to the prevention of fungi growth and of mycotoxins accumulation. Strategies followed to have control over the presence of mycotoxins in commodities will be illustrated by presenting case studies: (i) ochratoxin A in wine; and (ii) aflatoxins in maize and in nuts

    New 3‐ethynylaryl coumarin‐based dyes for dssc applications: Synthesis, spectroscopic properties, and theoretical calculations

    Get PDF
    PTDC/QUI‐QOR/7450/2020 POCI‐01‐0145‐FEDER‐016387 UIDB/50006/2020 UIDP/50006/2020 RECI/BBB‐BQB/0230/2012 RECI/BBB‐BEP/0124/2012 2020.09047.BD PD/BD/135087/2017 PD/BD/145324/2019/ (G.M.) .A set of 3‐ethynylaryl coumarin dyes with mono, bithiophenes and the fused variant, thieno [3,2‐b] thiophene, as well as an alkylated benzotriazole unit were prepared and tested for dye‐sensitized solar cells (DSSCs). For comparison purposes, the variation of the substitution pattern at the coumarin unit was analyzed with the natural product 6,7‐dihydroxycoumarin (Esculetin) as well as 5,7‐dihydroxycomarin in the case of the bithiophene dye. Crucial steps for extension of the conjugated system involved Sonogashira reaction yielding highly fluorescent molecules. Spectroscopic characterization showed that the extension of conjugation via the alkynyl bridge resulted in a strong red‐shift of absorption and emission spectra (in solution) of approximately 73–79 nm and 52–89 nm, respectively, relative to 6,7‐dimethoxy‐4‐methylcoumarin (λabs = 341 nm and λem = 410 nm). Theoretical density functional theory (DFT) calculations show that the Lowest Unoccupied Molecular Orbital (LUMO) is mostly centered in the cyanoacrylic anchor unit, corroborating the high intramolecular charge transfer (ICT) character of the electronic transition. Photovoltaic performance evaluation reveals that the thieno [3,2‐b] thiophene unit present in dye 8 leads to the best sensitizer of the set, with a conversion efficiency (η = 2.00%), best VOC (367 mV) and second best Jsc (9.28 mA∙cm−2), surpassed only by dye 9b (Jsc = 10.19 mA∙cm−2). This high photocurrent value can be attributed to increased donor ability of the 5,7‐dimethoxy unit when compared to the 6,7 equivalent (9b).publishersversionpublishe

    Self-assembled nanoparticles made of fucan

    Get PDF
    Amphiphilic polymers can self-assemble in water due to hydrophilic and hydrophobic interactions, forming nanoparticles (NPs) with unique physicochemical characteristics and thermodynamic stability. A non toxic sulfated Fucan, extracted from Spatoglossum schroederi was chemically modified by the grafting of Hexadecylamine (C16) to the polymer hydrophilic backbone. The resulting modified material (Fucan-C16) formed nanosized particles which were characterized by 1H NMR to assess the substitution degree of the hydrophobic chains, fluorescence spectroscopy to determine the critical aggregation concentration (cac), cryo-field emission scanning electron microscopy (Cryo- FESEM) to evaluate the shape and size of the NPs, and dynamic light scattering (DLS) to verify the size distribution. The (cac) of Fucan-C16 NPs ranged between 0.05 and 0.03mg/mL. Cryo-FESEM revealed that Fucan-C16 formed spherical macromolecular particles with diameters between 120 and 180 nm, which were confirmed by DLS. In addition, the size of the NPs were not affected by the concentration of the polymer or by the variation of the pH.The size of nanoparticles increases with increasing its concentration in solution.CAPES, FCT and CNP

    Dengue Infection Increases the Locomotor Activity of Aedes aegypti Females

    Get PDF
    BACKGROUND: Aedes aegypti is the main vector of the virus causing Dengue fever, a disease that has increased dramatically in importance in recent decades, affecting many tropical and sub-tropical areas of the globe. It is known that viruses and other parasites can potentially alter vector behavior. We investigated whether infection with Dengue virus modifies the behavior of Aedes aegypti females with respect to their activity level. METHODS/PRINCIPAL FINDINGS: We carried out intrathoracic Dengue 2 virus (DENV-2) infections in Aedes aegypti females and recorded their locomotor activity behavior. We observed an increase of up to ∌50% in the activity of infected mosquitoes compared to the uninfected controls. CONCLUSIONS: Dengue infection alters mosquito locomotor activity behavior. We speculate that the higher levels of activity observed in infected Aedes aegypti females might involve the circadian clock. Further studies are needed to assess whether this behavioral change could have implications for the dynamics of Dengue virus transmission

    Inhibitor of serine peptidase 2 enhances Leishmania major survival in the skin through control of monocytes and monocyte-derived cells

    Get PDF
    Leishmania major is the causative agent of the neglected tropical disease, cutaneous leishmaniasis. In the mouse, protective immunity to Leishmania is associated with inflammatory responses. Here, we assess the dynamics of the inflammatory responses at the lesion site during experimental long-term, low-dose intradermal infection of the ear, employing noninvasive imaging and genetically modified L. major Significant infiltrates of neutrophils and monocytes occurred at 1-4 d and 2-4 wk, whereas dermal macrophage and dendritic cell (DC) numbers were only slightly elevated in the first days. Quantitative whole-body bioluminescence imaging of myeloperoxidase activity and the quantification of parasite loads indicated that the Leishmania virulence factor, inhibitor of serine peptidase 2 (ISP2), is required to modulate phagocyte activation and is important for parasite survival at the infection site. ISP2 played a role in the control of monocyte, monocyte-derived macrophage, and monocyte-derived DC (moDC) influx, and was required to reduce iNOS expression in monocytes, monocyte-derived cells, and dermal DCs; the expression of CD80 in moDCs; and levels of IFN-Îł in situ. Our findings indicate that the increased survival of L. major in the dermis during acute infection is associated with the down-regulation of inflammatory monocytes and monocyte-derived cells via ISP2.-Goundry, A., Romano, A., Lima, A. P. C. A., Mottram, J. C., Myburgh, E. Inhibitor of serine peptidase 2 enhances Leishmania major survival in the skin through control of monocytes and monocyte-derived cells

    Hypertrophic Adenoid Is A Major Infection Site Of Human Bocavirus 1.

    Get PDF
    Human bocavirus 1 (HBoV1) is associated with respiratory infections worldwide, mainly in children. Similar to other parvoviruses, it is believed that HBoV1 can persist for long periods of time in humans, probably through maintaining concatemers of the virus single-stranded DNA genome in the nuclei of infected cells. Recently, HBoV-1 was detected in high rates in adenoid and palatine tonsils samples from patients with chronic adenotonsillar diseases, but nothing is known about the virus replication levels in those tissues. A 3-year prospective hospital-based study was conducted to detect and quantify HBoV1 DNA and mRNAs in samples of the adenoids (AD), palatine tonsils (PT), nasopharyngeal secretions (NPS), and peripheral blood (PB) from patients undergoing tonsillectomy for tonsillar hypertrophy or recurrent tonsillitis. HBoV1 was detected in 25.3% of the AD samples, while the rates of detection in the PT, NPS, and PB samples were 7.2%, 10.5%, and 1.7%, respectively. The viral loads were higher in AD samples, and 27.3% of the patients with HBoV had mRNA detectable in this tissue. High viral loads and detectable mRNA in the AD were associated with HBoV1 detection in the other sample sites. The adenoids are an important site of HBoV1 replication and persistence in children with tonsillar hypertrophy. The adenoids contain high HBoV1 loads and are frequently positive for HBoV mRNA, and this is associated with the detection of HBoV1 in secretions.523030-

    Dye-sensitized solar cells based on dimethylamino-π-bridge-pyranoanthocyanin dyes

    Get PDF
    UID/QUI/50006/2019 PTDC/QEQ-QFI/1971/2014 PD/BD/135087/2017 SFRH/BD/136556/2018 SFRH/BD/143309/2019 IF/00225/2015 DL57/2016 Program Contract (HC). UID/CTM/50025/2019 PTDC/CTM-ENE/5125/2014 CNPq 444061/2018-5 Universal grant 408181/2016-3The pyranoanthocyanins present in red wine display great potential as photosensitizers in bio-inspired Dye-Sensitized Solar Cells (DSSCs). Following a biomimetic approach, a series of amino-π-bridge-pyranoanthocyanin derivatives were employed as dye sensitizers in DSSCs. The dimethylamine group was selected to take advantage of its electron-donor character and the possibility of ‘dual-mode anchoring’ ([sbnd]OH vs. dimethylamino) to titanium dioxide. The increase in π-conjugation via insertion of C[dbnd]C bonds affected molecule flexibility, electron-donor ability and the pH-dependent equilibria of the pyranoanthocyanin derivatives. The current vs. potential properties of photoanodes using these dyes pointed to essential features of the relationship between power conversion efficiency and dye structure. These included the influences of the dimethylamine group, of π-conjugation and of substitution in ring B on the adsorption of the dyes to TiO2 and on the overall performance of the DSSCs prepared from them with and without added acid. An overall efficiency of 2.55% was obtained for the best performing compound, 4-(dimethylamino)-cinnamyl-pyranocyanidin-3-O-glucoside (JO3), which consolidates the importance of this family of compounds as potential dye-sensitizers for DSSC applications.authorsversionpublishe

    Induction of defense in apples by sulfated and deacetylated chichĂĄ gum.

    Get PDF
    Elicitors activate the defense mechanism in plants to resist pathogens. Ulvans and glucuronans can act as elicitors, and their activity seems to be related to the sulfate groups, rhamnose and uronic acid monosaccharides. ChichĂĄ gum (CHG), which also contains rhamnose and uronic acid, was sulfated with chlorosulfonic acid/N,N-dimethylformamide and deacetylated with sodium hydroxide solution. The changes were confirmed by infrared spectroscopy. Carbon-13 NMR revealed that sulfation occurred in galactose and rhamnose units. The apples were sprayed with water (negative control), deacetylated chichĂĄ gum (DCHG), and sulfated chichĂĄ gum (SCHG). The activity of enzymes guaiacol peroxidase and polyphenol oxidases and the lignin content were compared with those under the action of a commercial elicitor, benzothiadiazole. DCHG, and especially SCHG, increased the activity of the two enzymes. Only fruits treated with SCHG showed a significant (p<0.05) increase in lignin content. The plant exudate can be one abundant, renewable and safe source of elicitors. Keywords: benzothiadiazole (BTH), Sterculia striata, elicitor, polysaccharide, sulfation

    Histological and ultrastructural feature and nitrite production of caprine preantral follicles in vitro cultured in the presence or absence of serum

    Get PDF
    Avaliou-se o efeito da adição de diferentes tipos e concentraçÔes de soro sobre o desenvolvimento e a sobrevivĂȘncia de folĂ­culos ovarianos prĂ©-antrais (FOPA) caprinos in vitro. AlĂ©m disso, verificou-se a relação entre as concentraçÔes de nitrito presentes no meio de cultivo e a viabilidade folicular. Cada par ovariano foi dividido em 29 fragmentos, sendo um destinado ao controle. Os fragmentos foram cultivados por um ou sete dias em meio essencial mĂ­nimo suplementado (MEM+) ou MEM+ com diferentes concentraçÔes (10 ou 20%) de soro fetal bovino (SFB), soro de cabra em estro (SCE) ou soro de cabra em diestro (SCD). Na anĂĄlise morfolĂłgica apĂłs sete dias, apenas o tratamento com 10% de SFB apresentou percentual de FOPA normais similar ao MEM+ (P>0,05). A anĂĄlise ultra-estrutural dos folĂ­culos cultivados por sete dias com MEM+ ou MEM+ com 10% de SFB mostrou danos oocitĂĄrios, porĂ©m cĂ©lulas da granulosa normais. A anĂĄlise do meio de cultivo revelou correlação positiva entre a viabilidade folicular e a produção de nitrito. A suplementação com soro nĂŁo melhorou a viabilidade de FOPA e a concentração de nitrito no meio de cultivo funcionou como um indicador da viabilidade das cĂ©lulas da granulosa de FOPA caprinos cultivados in vitro. ______________________________________________________________________________________________________________ ABSTRACTThe effect of the addition of different types and concentrations of sera on the viability and development of caprine preantal follicles (PAF) in vitro cultured was analyzed. In addition, it was evaluated the correlation between nitrite concentrations in culture medium and folicular viability. Each ovarian pair was divided in 29 fragments and one was used as control. The fragments were cultured for one or seven days in minimal essential medium (MEM+) or MEM+ with different concentrations of (10 or 20%) bovine fetal serum (BFS), estrous goat serum (EGS), or diestrous goat serum (DGS). After seven days, the morphological analysis showed that only the treatment with 10% BFS maintained the percentage of normal PAF similar to MEM+ (P>0.05). The ultrastructural analysis of follicles cultured for seven days in MEM+ or MEM+ with 10% BFS showed some oocyte damage, although the granulosa cells were normal. Analysis of culture medium revealed a positive correlation between follicular viability and nitrite production. Supplementation with serum did not improve the viability of PAF and nitrite levels in culture medium served as an indicator of viability of granulose cells from caprine PAF in vitro cultured

    FITOQUÍMICA E ATIVIDADE FARMACOLÓGICA PRELIMINAR DO EXTRATO AQUOSO DE Tynanthus micranthus Corr. MĂ©llo ex K. Schum: UM EXEMPLO DA CAPACIDADE PREDITIVA E DOS CUSTOS NO DESENVOLVIMENTO DE NOVOS PRODUTOS FARMACÊUTICOS

    Get PDF
    Os produtos naturais tĂȘm servido de inspiração para o desenvolvimento de vĂĄrios produtos pela indĂșstria farmacĂȘutica local e mundial. O objetivo do presente trabalho foi avaliar a atividade farmacolĂłgica preliminar do extrato aquoso das folhas secas de Tynanthus micranthus, usando o teste hipocrĂĄtico em camundongos, como uma ferramenta para direcionar estudos farmacolĂłgicos futuros, bem como avaliar os custos envolvidos na execução deste estudo. AT. micranthus Corr. MĂ©llo ex K. Schum, conhecida popularmente como cipĂł-cravo, Ă© facilmente encontrada na regiĂŁo Noroeste do Estado do ParanĂĄ, Brasil, sendo utilizada pela população como calmante e analgĂ©sica. No entanto, existem poucos trabalhos cientĂ­ficos com esta espĂ©cie vegetal. O cĂĄlculo do custo contĂĄbil foi realizado para simular o valor gasto por uma empresa privada na realização destas atividades de Pesquisa e Desenvolvimento. Nossos resultados mostram que alĂ©m do baixo custo, o teste hipocrĂĄtico proporciona resultados importantes para a decisĂŁo da via de administração, toxicidade aguda, efeitos com altas doses e por diferentes vias, alĂ©m de fornecer informaçÔes sobre a latĂȘncia para os efeitos observados. Com essas informaçÔes e uma anĂĄlise fitoquĂ­mica mais aprofundada, isolando e identificando os compostos majoritĂĄrios, Ă© possĂ­vel avaliar na literatura a relação composto x atividade farmacolĂłgica direcionando de forma mais assertiva as pesquisas a serem realizadas. De maneira geral, apresentamos dados inĂ©ditos da espĂ©cie estudada (T. micranthus), mostrando uma estratĂ©gia de triagem farmacolĂłgica simples e de baixo custo para a pesquisa de plantas medicinais nativas que apresentem informaçÔes restritas na literatura e que possam servir para o desenvolvimento de novos produtos farmacĂȘuticos
    • 

    corecore