In this work, recycled paper sludge (RPS), composed of non-recyclable fibres, was used as a carbon source for bacterial nanocellulose (BNC) production. The biomass was enzymatically hydrolysed with ...Cellic CTec 2 to produce a sugar syrup with 45.40 g/L glucose, 1.69 g/L cellobiose and 2.89 g/L xylose. This hydrolysate was used for the optimization of BNC fermentation by static culture, using
Komagataeibacter xylinus
ATCC 700178
,
through response surface methodology (RSM). After analysis and validation of the model, a maximum BNC yield (5.69 g/L, dry basis) was obtained using 1.50% m/v RPS hydrolysate, 1.0% v/v ethanol and 1.45% m/v yeast extract/peptone (YE/P). Further, the BNC obtained was used to produce composites. A mixture of an amino-PolyDiMethylSiloxane-based softener, polyethyleneglycol (PEG) 400 and acrylated epoxidized soybean oil (AESO), was incorporated into the BNC membranes through an exhaustion process. The results show that BNC composites with distinct performances can be easily designed by simply varying the polymers percentage contents. This strategy represents a simple approach towards the production of BNC and BNC-based composites.
Recently, defense peptides that are able to act against several targets have been characterized. The present work focuses on structural and functional evaluation of the peptide analogue Pa-MAP, ...previously isolated as an antifreeze peptide from Pleuronectes americanus. Pa-MAP showed activities against different targets such as tumoral cells in culture (CACO-2, MCF-7 and HCT-116), bacteria (Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 25923), viruses (HSV-1 and HSV-2) and fungi (Candida parapsilosis ATCC 22019, Trichophyton mentagrophytes (28d&E) and T. rubrum (327)). This peptide did not show toxicity against mammalian cells such as erythrocytes, Vero and RAW 264.7 cells. Molecular mechanism of action was related to hydrophobic residues, since only the terminal amino group is charged at pH 7 as confirmed by potentiometric titration. In order to shed some light on its structure-function relations, in vitro and in silico assays were carried out using circular dichroism and molecular dynamics. Furthermore, Pa-MAP showed partial unfolding of the peptide changes in a wide pH (3 to 11) and temperature (25 to 95°C) ranges, although it might not reach complete unfolding at 95°C, suggesting a high conformational stability. This peptide also showed a conformational transition with a partial α-helical fold in water and a full α-helical core in SDS and TFE environments. These results were corroborated by spectral data measured at 222 nm and by 50 ns dynamic simulation. In conclusion, data reported here show that Pa-MAP is a potential candidate for drug design against pathogenic microorganisms due to its structural stability and wide activity against a range of targets.
Metabolomics is a powerful tool in diverse research areas, enabling an understanding of the response of organisms, such as plants, to external factors, their resistance and tolerance mechanisms ...against stressors, the biochemical changes and signals during plant development, and the role of specialized metabolites. Despite its advantages, metabolomics is still underused in areas such as nano-plant interactions. Nanoparticles (NPs) are all around us and have a great potential to improve and revolutionize the agri-food sector and modernize agriculture. They can drive precision and sustainability in agriculture as they can act as fertilizers, improve plant performance, protect or defend, mitigate environmental stresses, and/or remediate soil contaminants. Given their high applicability, an in-depth understanding of NPs' impact on plants and their mechanistic action is crucial. Being aware that, in nano-plant interaction work, metabolomics is much less addressed than physiology, and that it is lacking a comprehensive review focusing on metabolomics, this review gathers the information available concerning the metabolomic tools used in studies focused on NP-plant interactions, highlighting the impact of metal-based NPs on plant metabolome, metabolite reconfiguration, and the reprogramming of metabolic pathways.
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•TiO2-NP are global emergent contaminants, with unclear effects on crop metabolism.•TiO2-NP compromised carbohydrates synthesis, triggering starch and disaccharides ...catabolism.•Metabolism privileged amino acids, in detriment of sugars, to feed the TCA cycle.•Leaves up-regulated shikimate pathways, amino acids and glycerolipids.•Roots up-regulated the monosaccharides, proline, azelaic acid, and GABA.
TiO2-nanoparticles (TiO2-NP) have the potential to impair plant development. Nevertheless, the metabolic processes behind the physiological responses to TiO2-NP are still far from being fully understood. In this study, Triticum aestivum plants were exposed for 21 days to different concentrations (0; 5; 50; 150 mg L−1) of TiO2-NP (P25). After treatment, the metabolite profiles of roots and leaves were analysed. The content of >70 % of the identified metabolites changed in response to P25 and the impact on metabolic pathways increased with TiO2-NP dose, with leaves showing higher alterations. Roots up-regulated monosaccharides, azelaic acid, and γ-aminobutanoic acid and triggered the tyrosine metabolism, whereas leaves up-regulated the metabolisms of reserve sugars and tocopherol, and the phenylalanine and tryptophan pathways. Both organs (mainly leaves) up-regulated the aspartate family pathway together with serine, alanine and valine metabolisms and the glycerolipids’ biosynthesis. In addition, the citrate and glyoxylate metabolisms were down-regulated in both organs (highest dose). Sugar biosynthesis breakdown, due to photosynthetic disturbances, shifted the cell metabolism to use amino acids as an alternative energy source, and both ROS and sugars worked as signalling molecules activating organ dependent antioxidant responses. Concluding, these NP-pollutants severely impact multiple crop metabolic pathways and may ultimately compromise plant performance.
A nano-molecularly imprinted polymer (N-MIP) assembled on a screen-printed electrode for the cardiac troponin T (cTnT) was developed. The biomimetic surface was obtained by a co-polymer matrix ...assembled on the reduced graphene oxide (RGO) electrode surface. The cTnT active sites were engineered using pyrrole and carboxylated pyrrole that was one-step electropolymerized jointly with cTnT by cyclic voltammetry. The stepwise preparation of the biomimetic surface was characterized by cyclic and differential pulse voltammetries using the ferrocyanide/ferricyanide as redox probe. Structural and morphological characterization was also performed. The optimal relation of pyrrole and pyrrole-3-acid carboxylic to perform the cTnT biomimetic nanosurface was obtained at 1:5 ratio. The analytical performance of cTnT N-MIP performed by differential pulse voltammetry showed a linear range from 0.01 to 0.1ngmL−1 (r=0.995, p«0.01), with a very low limit of detection (0.006ngmL−1). The synergic effect of conductive polymer and graphene forming 3D structures of reactive sites resulted in a N-MIP with excellent affinity to cTnT binding (KD=7.3 10−13molL−1). The N-MIP proposed is based on a simple method of antibody obtaining with a large potential for point-of-care testing applications.
•A biomimetic sensor as imprinted thin-film was developed to cardiac troponin T.•A sensor was assembled based on graphene and conductive polymer synergism.•The biomimetic sensor was assembled onto a disposable screen-printed electrode.•The functionalized pyrrole was explored to mimetizes the cTnT antibodies.•The biomimetic cTnT sensor achieved a good limit of detection (0.006ngmL−1).
Microwave irradiation has become a popular heating technique in organic synthesis, mainly due to its short reaction times, solventless reactions, and, sometimes, higher yields. Additionally, ...microwave irradiation lowers energy consumption and, consequently, is ideal for optimization processes. Moreover, there is evidence that microwave irradiation can improve the regioselectivity and stereoselectivity aspects of vital importance in synthesizing bioactive compounds. These crucial features of microwave irradiation contribute to its inclusion in green chemistry procedures. Since 2003, the use of microwave-assisted organic synthesis has become common in our laboratory, making our group one of the first Portuguese research groups to implement this heating source in organic synthesis. Our achievements in the transformation of heterocyclic compounds, such as (
/
)-3-styryl-4
-chromen-4-ones, (
)-3-(2-hydroxyphenyl)-4-styryl-1
-pyrazole, (
)-2-(4-arylbut-1-en-3-yn-1-yl)-4
-chromen-4-ones, or (
)-2-2-(5-aryl-2-methyl-2
-1,2,3-triazol-4-yl)vinyl-4
-chromen-4-ones, will be discussed in this review, highlighting the benefits of microwave irradiation use in organic synthesis.
To understand how olives reconfigure their metabolism to face stress shock episodes, plants from the economically relevant olive (Olea europaea cv. Cobrançosa) were exposed to high UV–B radiation ...(UV–B, 12 kJ m–2 d–1) or heat shock (HS, 40 °C) for two consecutive days. The physiological responses and some important lipophilic compounds were evaluated immediately (day 0) and 30 days after UV–B or HS episodes. Both treatments induced a reduction of the olive physiological performance, particularly increasing cell membrane damages and proline pool and at the same time reducing chlorophyll levels, the quantum yield of photosystem II (ΦPSII), and the efficiency of excitation energy capture by open photosystem II (PSII) reaction centers (F′ v/F′ m). Nevertheless, the HS episode caused more adverse effects, additionally reducing the pool of protective pigments (carotenoids) and the maximum efficiency of PSII (with F 0 increase). In the UV–B treatment, despite the higher lipid peroxidation, the activation of some stress protective mechanisms (e.g., increase of NPQ and carotenoids and remobilization of some metabolites, such as phytol and proline) might have contributed to avoiding photoinhibition. Thirty days after stress relief, the performance of olives from both treatments recovered similarly, in part due to the metabolites’ adjustments that contributed to strengthened stress protection (an increase of long-chain alkanes) and provided energy (through the use of soluble sugars, mannitol, and myo-inositol) for re-establishment. Other metabolites, like anthocyanins and squalene, also have an important role in responding specifically to HS or UV–B recovery for helping in the oxidative damage control. These data contribute to understanding how young olive plants may deal with climatic episodes when being transferred from nurseries to field orchards, under the actual context of climate change.
Candida parapsilosis is a healthcare-related fungal pathogen particularly common among immunocompromised patients. Our understanding of antifungal resistance mechanisms in C. parapsilosis remains ...very limited. We previously described an azole-resistant strain of C. parapsilosis (BC014RPSC), obtained following exposure in vitro to posaconazole. Resistance was associated with overexpression of ergosterol biosynthetic genes (ERG genes), together with the transcription factors UPC2 (CPAR2-207280) and NDT80 (CPAR2-213640). The aim of this study was to identify the mechanisms underlying posaconazole resistance of the BC014RPSC strain.
To identify the causative mutation, we sequenced the genomes of the susceptible (BC014S) and resistant (BC014RPSC) isolates, using Illumina technology. Ergosterol content was assessed in both strains by mass spectrometry. UPC2 and NDT80 genes were deleted in BC014RPSC strain. Mutants were characterized regarding their azole susceptibility profile and ERG gene expression.
One homozygous missense mutation (R135I) was found in ERG3 (CPAR2-105550) in the azole-resistant isolate. We show that Erg3 activity is completely impaired, resulting in a build up of sterol intermediates and a failure to generate ergosterol. Deleting UPC2 and NDT80 in BC014RPSC reduces the expression of ERG genes and restores susceptibility to azole drugs.
A missense mutation in the ERG3 gene results in azole resistance and up-regulation of ERG genes expression. We propose that this mutation prevents the formation of toxic intermediates when cells are treated with azoles. Resistance can be reversed by deleting Upc2 and Ndt80 transcription factors. UPC2 plays a stronger role in C. parapsilosis azole resistance than does NDT80.
This work describes the electrochemical degradation of Reactive Black 5 (RB5) by two methods: electrochemical and photo-assisted electrochemical degradation with and without a Fenton reagent. Two ...anodes were used, Pt and boron-doped diamond (BDD, 2500 ppm), and the cathode was 3% MnO2 nanoflowers (NFMnO2) on a carbon gas diffusion electrode (GDE). An electrochemical cell without a divider with a GDE with 3% w/w NFMnO2/C supported on carbon Vulcan XC72 was used. The decolorization efficiency was monitored by UV–vis spectroscopy, and the degradation was monitored by Total Organic Carbon (TOC) analysis. For dissolution monitoring, aliquots (1 mL) were collected during the degradation. After 6 h of H2O2 electrogeneration, the manganese concentration in the RB5 solution was only 23.1 ± 1.2 μg L−1. It was estimated that approximately 60 μg L−1 (<0.2%) of manganese migrated from the GDE to the solution after 12 h of electrolysis, which indicated the good stability of the GDE. The photoelectro-Fenton-BDD (PEF-BDD) processes showed both the best color removal percentage (∼93%) and 91% of mineralization. The 3% NFMnO2/C GDE is promising for RB5 degradation.
•The (PEF-BDD) processes showed both the best color removal 93% and mineralization 91%.•The results indicate the good stability of 3% NFMnO2/C GDE during electrolysis.•The 3% NFMnO2/C GDE is promising for RB-5 degradation.
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