LSRE-LCM - Artigos em Revistas Nacionais e de Circulação Internacional
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- Molecular Dissection of Escherichia coli CpdB: Roles of the N Domain in Catalysis and Phosphate Inhibition, and of the C Domain in Substrate Specificity and Adenosine InhibitionPublication . López-Villamizar, Iralis; Cabezas, Alicia; Pinto, Rosa María; Canales, José; Ribeiro, João Meireles; Rodrigues, Joaquim Rui; Costas, María Jesús; Cameselle, José CarlosCpdB is a 3′-nucleotidase/2′ 3′-cyclic nucleotide phosphodiesterase, active also with rea-sonable efficiency on cyclic dinucleotides like c-di-AMP (3′,5′-cyclic diadenosine monophosphate) and c-di-GMP (3′,5′-cyclic diadenosine monophosphate). These are regulators of bacterial physi-ology, but are also pathogen-associated molecular patterns recognized by STING to induce IFN-β response in infected hosts. The cpdB gene of Gram-negative and its homologs of gram-positive bacteria are virulence factors. Their protein products are extracytoplasmic enzymes (either periplas-mic or cell–wall anchored) and can hydrolyze extracellular cyclic dinucleotides, thus reducing the innate immune responses of infected hosts. This makes CpdB(-like) enzymes potential targets for novel therapeutic strategies in infectious diseases, bringing about the necessity to gain insight into the molecular bases of their catalytic behavior. We have dissected the two-domain structure of Escherichia coli CpdB to study the role of its N-terminal and C-terminal domains (CpdB_Ndom and CpdB_Cdom). The specificity, kinetics and inhibitor sensitivity of point mutants of CpdB, and truncated proteins CpdB_Ndom and CpdB_Cdom were investigated. CpdB_Ndom contains the catalytic site, is inhibited by phosphate but not by adenosine, while CpdB_Cdom is inactive but contains a substrate-binding site that determines substrate specificity and adenosine inhibition of CpdB. Among CpdB substrates, 3′-AMP, cyclic dinucleotides and linear dinucleotides are strongly dependent on the CpdB_Cdom binding site for activity, as the isolated CpdB_Ndom showed much-diminished activity on them. In contrast, 2′,3′-cyclic mononucleotides and bis-4-nitrophenylphosphate were actively hydrolyzed by CpdB_Ndom, indicating that they are rather independent of the CpdB_Cdom binding site.
- Rafting on the Evidence for Lipid Raft-like Domains as Hubs Triggering Environmental Toxicants’ Cellular EffectsPublication . Marques-da-Silva, Dorinda; Lagoa, RicardoThe plasma membrane lipid rafts are cholesterol- and sphingolipid-enriched domains that allow regularly distributed, sub-micro-sized structures englobing proteins to compartmentalize cellular processes. These membrane domains can be highly heterogeneous and dynamic, functioning as signal transduction platforms that amplify the local concentrations and signaling of individual components. Moreover, they participate in cell signaling routes that are known to be important targets of environmental toxicants affecting cell redox status and calcium homeostasis, immune regulation, and hormonal functions. In this work, the evidence that plasma membrane raft-like domains operate as hubs for toxicants’ cellular actions is discussed, and suggestions for future research are provided. Several studies address the insertion of pesticides and other organic pollutants into membranes, their accumulation in lipid rafts, or lipid rafts’ disruption by polychlorinated biphenyls (PCBs), benzo[a]pyrene (B[a]P), and even metals/metalloids. In hepatocytes, macrophages, or neurons, B[a]P, airborne particulate matter, and other toxicants caused rafts’ protein and lipid remodeling, oxidative changes, or amyloidogenesis. Different studies investigated the role of the invaginated lipid rafts present in endothelial cells in mediating the vascular inflammatory effects of PCBs. Furthermore, in vitro and in vivo data strongly implicate raft-localized NADPH oxidases, the aryl hydrocarbon receptor, caveolin-1, and protein kinases in the toxic mechanisms of occupational and environmental chemicals.
- A Community-Based Participatory Framework to Co-Develop Patient Education Materials (PEMs) for Rare Diseases: A Model Transferable across DiseasesPublication . Falcão, Marta; Allocca, Mariateresa; Rodrigues, Ana Sofia; Granjo, Pedro; Francisco, Rita; Pascoal, Carlota; Rossi, Maria Grazia; Marques-da-Silva, Dorinda; Magrinho, Salvador C. M.; Jaeken, Jaak; Castro, Larisa Aragon; Freitas, Cláudia de; Videira, Paula A.; Andrés-Aguayo, Luísa de; Ferreira, Vanessa dos ReisAt least 50% of chronic disease patients don’t follow their care plans, leading to lower health outcomes and higher medical costs. Providing Patient Education Materials (PEMs) to individuals living with a disease can help to overcome these problems. PEMs are especially beneficial for people suffering from multisystemic and underrecognized diseases, such as rare diseases. Congenital disorders of glycosylation (CDG) are ultra-rare diseases, where a need was identified for PEMs in plain language that can clearly explain complex information. Community involvement in the design of PEMs is extremely important for diseases whose needs are underserved, such as rare diseases; however, attempts to involve lay and professional stakeholders are lacking. This paper presents a community-based participatory framework to co-create PEMs for CDG, that is transferable to other diseases. A literature review and questionnaire were performed, and only four articles describing the development of PEMS for rare diseases have been found, which demonstrates a lack of standardized approaches. The framework and PEMs were co-developed with CDG families and will be crucial in increasing health literacy and empowering families. We will close a gap in the creation of PEMs for CDG by delivering these resources in lay language in several languages.
- SoResilere—A Social Resilience Index Applied to Portuguese Flood Disaster-Affected MunicipalitiesPublication . Jacinto, Rita; Sebastião, Fernando; Reis, Eusébio; Ferrão, JoãoDecades of academic discussion on social resilience have led to the development of indicators, indexes, and different approaches to assessing it at national and local levels. The need to show real-world applications of such assessments is evident since resilience became a political and disaster risk reduction governance component. This article gives a full description of the methodology used to develop SoResilere, a new social resilience index applied to flood disaster-affected Portuguese municipalities. Study cases were selected according to historical databases, academic sources and governmental entities. Statistical methods for data dimension reduction, such as Factor Analysis (through Principal Component Analysis), were applied to the quantitative data and Optimal Scaling to the categorical data. SoResilere results were analyzed. Since SoResilere is a new tool, component weighting was applied to compare results with no weighting, although it did not affect the SoResilere status in 55.5% of the study cases. There is a tendency to look at the improvement of SoResilere results with component weighting due mainly to the quantitative subindex. There is no evidence of the benefits of component weighting, as no logical association or spatial pattern was found to support SoResilere status improvement in 22.22% of the study cases.
- Optimization of an Indoor DWC Hydroponic Lettuce Production System to Generate a Low N and P Content WastewaterPublication . Aires, Luis M. I.; Ispolnov, Kirill; Luz, Tomás R.; Pala, Helena; Vieira, Judite S.Hydroponic production raises economic and environmental issues related to the treatment, recovery or disposal of hydroponic wastewater, which can be rich in eutrophication-related nutrients, nitrogen (N) and phosphorus (P). Little focus has been put on the influence of the growth conditions on the N and P content in hydroponic wastewater, which is of uttermost importance when it is intended to reuse the wastewater for irrigation or other purposes with reduced impact on the environment. This study aimed to optimize an indoor non-recirculating deep-water culture (DWC) hydroponic system for lettuce (Lactuca sativa L. var. crispa) production, in terms of daily light integral (DLI) and volume of nutrient solution (NS) per plant, to maximize both the biomass production and the N and P removal, allowing for the wastewater to meet the criteria established for reusing in irrigation and minimizing the eutrophication impacts. A small-scale DWC hydroponic system with a fluorescent light fixture was built to study lettuce growth indoors for 35 days after transplanting (DAT). A first experiment was conducted under 14, 20 or 23 mol m−2 d−1 DLI and with 1.5 or 2 L of NS per plant. A pronounced inner leaf tip burn was observed, regardless of the volume of NS solution used, related to the unventilated conditions under high radiation. Total biomass was similar in all treatments and N and P removal was higher than 95% and 94%, respectively, at 35 DAT. Lettuces grown in 2 L of NS per plant exhibited higher average biomass. A second experiment was performed under 8, 10 or 12 mol m−2 d−1 DLI and with 2 or 3 L of NS per plant, making it possible to achieve healthy biomass at 35 DAT with higher water and light-use efficiency when compared to the first experiment. A DLI of 10 or 12 mol m−2 d−1 with 2 L of NS per plant and a DLI of 12 mol m−2 d−1 with 3 L of NS per plant made it possible to achieve both the best total biomass production and the highest N and P removal from water. Under those conditions, hydroponic wastewater complied with N and P criteria for reuse in irrigation, showing potential to be used as an alternative resource for agriculture and to minimize negative impacts on the environment.
- Determination of the biochemical methane potential of swine hydrolyzatePublication . Domingues, Paulo Simão; Oliveira, Nelson Simões; Ribeiro, Ana M.; Ferreira, Alexandre; Pala, HelenaSwine farming generates remains of births and animals that die during the process. Implementing a plan to eliminate these materials by hydrolysis process results in an animal by-product called swine hydrolyzate. The treatment of this by-product through its application in the anaerobic digestion process can also represent its conversion into a resource for energy production. Thus, the present study focuses on this by-product as a potential substrate for anaerobic digestion, evaluating the methane production potential. The results show biogas production with an average methane content of about 70 %. Theoretical biochemical methane potential was 967.95 ± 0.11 mL g VS−1, which represented a bioconversion efficiency of 59.97 ± 3.54 % and 62.26 ± 0.43 %, considering the experimental results of 580.47 ± 34.29 mL g VS−1 and 602.67 ± 4.16 mL g VS−1, respectively. By comparing the experimental biochemical methane potential with the predicted value using the modified Gompertz model, it was possible to conclude that the maximum methane production rate was 73.46 ± 0.36 mL g VS−1 day−1, with a digestion time of 18 days to obtain 90 % of the methane production potential.
- Removal of Hydrophobic Organic Pollutants and Copper by Alginate-Based and Polycaprolactone MaterialsPublication . Marques-da-Silva, Dorinda; Lopes, João M.; Correia, Iris; Silva, João S.; Lagoa, RicardoOrganic pollutants (OPs) and heavy metals are environmental toxicants associated with great concerns. Decontamination processes are urgent for both, and the possibility to achieve their simultaneous removal from polluted waters is highly interesting. Additionally, in many cases, the effect of organic matter in the removal process is overlooked and must be considered. This work aimed to study the potential of alginate-based and polycaprolactone (PCL) materials to remove OPs and copper ions in the absence and presence of organic matter. The OPs investigated were the polycyclic aromatic hydrocarbons anthracene and benzo[a]pyrene, and the pesticide chlorpyrifos, both hydrophobic compounds. Copper (II) ions were used as a model of heavy metals. Alginate-based spheres were prepared by gelation, and PCL microparticles were obtained by oil/water emulsion solvent evaporation. The materials with the highest efficiencies for OP removal from aqueous solutions were those with activated carbon and PCL. Furthermore, the spheres with activated carbon could remove anthracene and copper simultaneously, even in the presence of humic acid. This work points to activated carbon–alginate spheres as a multifunctional adsorbent able to remove different pollutants and to PCL for potential applications in OP decontamination processes.
- Complexation and DFT studies of lower rim hexahomotrioxacalix[3]arene derivatives bearing pyridyl groups with transition and heavy metal cations. Cone versus partial cone conformationPublication . Marcos, Paula M.; Teixeira, Filipa A.; Segurado, Manuel A. P.; Ascenso, José R.; Bernardino, Raul; Peter J. Cragg; Sylvia Michel; Véronique Hubscher-Bruder; Françoise Arnaud-NeuThe binding of representative alkali, alkaline earth, transition and heavymetal cations by 2-pyridylmethoxy derivatives (1b, in cone and partial cone conformations) of p-tert-butylhexahomotrioxacalix[3]arene was studied. Binding was assessed by extraction studies of the metal picrates from water into dichloromethane and by stability constant measurements in acetonitrile and methanol, using spectrophotometric and potentiometric techniques. Microcalorimetric studies of some selected complexes in acetonitrile were performed, as well as proton NMR titrations. Computational methods (density functional theory calculations) were also employed to complement the NMR data. The results are compared with those obtained with the dihomooxacalix[4]arene 2b and the calix[4]arene 3b derivative analogues. Partial cone-1b is the best extractant for transition and heavy metal cations. Both conformers of 1b exhibit very high stability constants for soft and intermediate cations Pb2+, Cd2+, Hg2+, Zn2+ and Ni2+, with cone-1b the strongest binder (ML, log b ≥7) and partial cone-1b the most selective. Both derivatives show a slight preference for Na+. Besides the formation of ML complexes, ML2 and M2L species were also observed. The former complexes were, in general, formed with the transition and heavy metal cations, whereas the latter were obtained with Ag+ and Hg2+ and partial cone-1b. In most cases, these species were corroborated by the proton NMR and density functional theory studies.
- Comparison of Laccases and Hemeproteins Systems in Bioremediation of Organic PollutantsPublication . Lopes, João M.; Marques-da-Silva, Dorinda; Videira, Paula Q.; Lagoa, Ricardo L.Aim: Laccases and peroxidases have attracted great interest for industrial and environmental applications. These enzymes have a broad substrate range and a robust oxidizing ability. Moreover, using mediators or co-oxidants makes it possible to increase their catalytic activity and extend their substrate scope to more resistant chemical structures. Background: Fungal laccases and ligninolytic peroxidases, mainly lignin and manganese peroxidases, are the privileged oxidoreductases for bioremediation processes. Nonetheless, an increasing diversity of laccases and peroxidase-type enzymes has been proposed for environmental technologies. Objective: This article aims to provide an overview of these enzymes and compare their applicability in the degradation of organic pollutants. Methods: Fundamental properties of the proteins are covered and applications towards polycyclic aromatic hydrocarbons (PAHs) and pesticides are specially focused. Results: Laccases are multicopper oxidases initially studied for applications in the pulp and paper in-dustry but able to oxidize a variety of environmentally concerning compounds. Relying on O2, laccases do not require peroxides nor auxiliary agents, like Mn2+, although suitable redox mediators are needed to attack the more recalcitrant pollutants (e.g., PAHs). True and pseudo-peroxidases use a stronger oxi-dant (H2O2) and the redox chemistry at the heme site generates high potential species that allow the oxidation of dyes and some pesticides. Conclusion: Lately, research efforts have been directed to enzyme discovery, testing with micropollu-tants, and improving biocatalysts’ stability by immobilization and protein engineering. Further under-standing of the effects of natural media components and solvents on the enzymes might lead to compet-itive enzymatic treatments of highly toxic media.
- Complexation and DFT studies of lanthanide ions by (2-pyridylmethoxy)homooxacalixarene derivativesPublication . Marcos, Paula M.; Teixeira, Filipa A.; Segurado, Manuel A.P.; Ascenso, José R.; Bernardino, Raul; Cragg, Peter J.; Michel, Sylvia; Hubscher-Bruder, Véronique; Arnaud-Neu, FrançoiseThe binding of lanthanide cations by 2-pyridylmethoxy derivatives of p-tert-butyldihomooxacalix[4]arene (1b), in the cone conformation, and p-tert-butylhexahomotrioxacalix[3]arene (2b), in both cone and partial cone conformations, was studied. These properties were assessed by extraction studies of the metal picrates from water into dichloromethane and stability constant measurements in methanol and acetonitrile, using spectrophotometric and microcalorimetric techniques. Proton NMR titrations with La3+ and Yb3+ cations were done in order to get information on the binding sites. Computational methods (density functional theory (DFT) calculations) were also used to complement the NMR data. The p-tert-butylcalix[4]arene analogue (3b) was also studied, and the results of the four ligands were compared. Partial cone-2b is the best extractant for lanthanide ions, showing some preference for the heavy lanthanides. In complexation, all four ligands show the same trend and a high selectivity for Yb3+ (ML, log β ≥ 7). Besides the formation of ML complexes, ML2 species were also obtained. In most cases, these species were corroborated by the proton NMR studies. For partial cone-2b with Pr3+ the complexation process is enthalpically driven, whereas for 3b the formation of the ML2 species with this cation is due to a favourable entropy term. DFT studies indicate that ligand 3b forms the most stable complex with La3+, followed by partial cone-2b.
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