Beira, MJ, Daniel CI, Almeida PL, Corvo MC, Rosatella AA, Afonso CAM, Sebastiao PJ.
2017.
1H NMR Relaxometry and Diffusometry Study of Magnetic and Non-Magnetic Ionic Liquid-Based Solutions: Co-Solvent and Temperature Effects. The Journal of Physical Chemistry B. : ACS Publications
AbstractIn this work, 1H NMR relaxometry and diffusometry as well as viscometry experiments were carried out as a means to study the molecular dynamics of magnetic and non-magnetic ionic liquid-based systems. In order to evaluate the effect of a co-solvent on the super-paramagnetic properties observed for Aliquat-iron-based magnetic ionic liquids, mixtures comprising different concentrations, 1% and 10% (v/v), of DMSO-d6 were prepared and analyzed. The results suggest that, when at low concentrations, DMSO-d6 promotes more structured ionic arrangements, thus enhancing these super-paramagnetic properties. Furthermore, the analysis of temperature and water concentration effects allowed to conclude that neither one of these variables sufficiently affected the super-paramagnetic properties of the studied magnetic ionic liquids.
Marques, AC, Santos L, Dantas JM, Gonçalves A, Casaleiro S, Martins R, Salgueiro CA, Fortunato E.
2017.
Advances in electrochemically active bacteria: Physiology and ecology. Handbook of Online and Near-real-time Methods in Microbiology. : CRC Press
AbstractThe discovery of microorganisms with the ability of Extracellular Electron Transfer (EET), nearly three decades ago, sparked interest due to their ability to be used in diverse applications that can range from bioremediation to electricity production in Microbial Fuel Cells (MFC). Microbial respiration is based on electron transfer from a donor to an electron acceptor, through a series of stepwise electron transfer events that generate the necessary metabolic energy. Some microorganisms, such as Pseudomonas species, Shewanella putrefaciens or Geothrix fermentans are able to produce electrochemical mediators to increase the EET. The mechanical stability of the biofilm is provided by the biofilm matrix, a hydrated extracellular polymeric matrix that encases the biofilm cells. The biofilm matrix could potentially offer a resistance pathway to EET unless bacteria develop strategies to increase its conductivity. MFC devices currently being used and studied do not generate sufficient power to support widespread and cost-effective applications.
Berride, F, Troche-Pesqueira E, Feio G, Cabrita EJ, Sierra T, Navarro-Vázquez A, Cid MM.
2017.
Chiral amplification of disodium cromoglycate chromonics induced by a codeine derivative. Soft Matter. 13(38):6810-6815.
AbstractChromonic liquid crystals (CLC) are lyotropic phases formed by discotic mesogens in water. Simple chiral dopants such as amino acids have been reported to turn chromonic liquid crystals into their cholesteric counterparts. Here we report a chirality amplification effect in the nematic phase of a 9 wt% disodium cromoglycate (DSCG) lyotropic liquid crystal (LLC) upon doping with a water-soluble codeine derivative. The transition on cooling the isotropic to the nematic phase showed the presence of homochiral spindle-shaped droplets (tactoids). NMR DOSY experiments on a triple gradient probe revealed a small degree of diffusion anisotropy for the alkaloid embedded in the liquid crystal structure. These results in combination with XRD, CD and POM experiments agree with a supramolecular aggregation model based on simple columnar stacks.
Ribeiro, SO, Nogueira LS, Gago S, Almeida PL, Corvo MC, de Castro B, Granadeiro CM, Balula SS.
2017.
Desulfurization Process conciliating Heterogeneous Oxidation and liquid extraction: Organic Solvent or Centrifugation/Water? Applied Catalysis A: General. : Elsevier
AbstractThe present work presents a strategic oxidative desulfurization system able to efficiently operate under sustainable conditions, i.e. using an eco-friendly oxidant and without the need of extractive organic solvents. The catalytic performance of Eu(PW11O39)2@aptesSBA-15 was evaluated for the oxidative desulfurization of a multicomponent model diesel using a solvent-free or biphasic systems. The results reveal its remarkable desulfurization performance achieving complete desulfurization after just 2 h of reaction. Moreover, the composite has shown a high recycling ability without loss of catalytic activity for ten consecutive ODS cycles. Interestingly, under solvent-free conditions it was possible to maintain the desulfurization efficiency of the biphasic system while being able to avoid the use of harmful organic solvents. In this case, a successful extraction of oxidized sulfur compounds was found conciliating centrifugation and water as extraction solvent. Therefore, this work reports an important step towards the development of novel eco-sustainable desulfurization systems with high industrial interest.
Peixoto, D, Figueiredo M, Gawande MB, Corvo MC, Vanhoenacker G, Afonso CAM, Ferreira LM, Branco PS.
2017.
DEVELOPMENTS IN THE REACTIVITY OF 2-METHYL IMIDAZOLIUM SALTS. The Journal of Organic Chemistry. 82(12):6232–6241.: American Chemical Society
AbstractUnexpected and unusual reactivity of 2-methylimidazolium salts toward aryl-N-sulfonylimines and aryl aldehydes is here reported. Upon reaction with aryl-N-sulfonylimines, the addition product, arylethyl-2-imidazolium-1-tosylamide (3), is formed with moderate to good yields, while upon reaction with aldehydes, the initial addition product (6) observed in NMR and HPLC–MS experimental analysis is postulated by us as an intermediate to the final conversion to carboxylic acids. Studies in the presence and absence of molecular oxygen allow us to conclude that the imidazolium salts is crucial for the oxidation. A detailed mechanistic study was carried out to provide insights regarding this unexpected reactivity.
Dajkovic, A, Tesson B, Chauhan S, Courtin P, Keary R, Flores P, Marliere C, Filipe SR, Chapot-Chartier M-P, Carballido-Lopez R.
2017.
Hydrolysis of Peptidoglycan is Modulated by Amidation of meso-Diaminopimelic Acid and Mg2+ in Bacillus subtilis. Mol. Microbiol. 104:972-988.
Pauleta, SR, Carreira C, Moura I.
2017.
Insights into nitrous oxide reductase. Metalloenzymes in Denitrification: Applications and Environmental Impacts, RSC Metallobiology Series No. 9 (ISBN: 978-1-78262-376-2).. (
Moura, I., Moura, J. J. G., Pauleta, S. R., Maia, L. B., Eds.).:141-169.: Royal Society of Chemistry
Ferreira, J, Santos T, Pereira P, Corvo MC, Queiroz JA, Sousa F, Cruz C.
2017.
Naphthalene amine support for G-quadruplex isolation. Analyst. 142(16):2982-2994.: Royal Society of Chemistry
AbstractG-quadruplex (G4) is involved in many biological processes, such as telomere function, gene expression and DNA replication. The selective isolation of G4 using affinity ligands that bind tightly and selectively is a valuable strategy for discovering new G4 binders for the separation of G4 from duplexes or the discrimination of G4 structures. In this work, one affinity chromatographic support was prepared using a naphthalene amine as a G4 binder. The ligand was immobilized on epoxy-activated Sepharose CL-6B using a long spacer arm and was characterized by HR-MAS spectroscopy. The supercoiled (sc) isoform of pVAX1-LacZ and pVAX1-G4 was isolated from a native sample. Also, the recovery and isolation of the plasmid isoforms from Escherichia coli lysate samples were achieved using an ionic gradient with different concentrations of NaCl in 10 mM Tris-HCl (pH 7.4). The retention times of different DNA/single strand sequences that can form G4, such as, c-MYC, c-kit1, c-kit2, tetrameric, telomeric (23AG), thrombin aptamer (TBA) and 58Sγ3 in this support were evaluated. Our experimental results suggest that the support exhibits selectivity for parallel c-MYC and c-kit1 G4s. In vitro transcription was performed using purified sc pVAX1-G4 and pPH600 to induce G4 formation and circular dichroism (CD) analysis confirmed that both transcripts adopt a parallel G4 topology.
Mancio-Silva, L, Slavic K, Ruivo MGT, Grosso AR, Modrzynska KK, Vera IM, Sales-dias J, Gomes AR, Macpherson CR, Crozet P, Adamo M, Baena-gonzalez E, Tewari R, Llinás M, Billker O, Mota MM.
2017.
Nutrient sensing modulates malaria parasite virulence. Nature. : Nature Publishing Group
AbstractThe lifestyle of intracellular pathogens, such as malaria parasites, is intimately connected to that of their host, primarily for nutrient supply. Nutrients act not only as primary sources of energy but also as regulators of gene expression, metabolism and growth, through various signalling networks that enable cells to sense and adapt to varying environmental conditions. Canonical nutrient-sensing pathways are presumed to be absent from the causative agent of malaria, Plasmodium, thus raising the question of whether these parasites can sense and cope with fluctuations in host nutrient levels. Here we show that Plasmodium blood-stage parasites actively respond to host dietary calorie alterations through rearrangement of their transcriptome accompanied by substantial adjustment of their multiplication rate. A kinome analysis combined with chemical and genetic approaches identified KIN as a critical regulator that mediates sensing of nutrients and controls a transcriptional response to the host nutritional status. KIN shares homology with SNF1/AMPKα, and yeast complementation studies suggest that it is part of a functionally conserved cellular energy-sensing pathway. Overall, these findings reveal a key parasite nutrient-sensing mechanism that is critical for modulating parasite replication and virulence.
dos Santos, R, Carvalho AL, Roque ACA.
2017.
Renaissance of protein crystallization and precipitation in biopharmaceuticals purification. Biotechnology Advances. 35:–., Number 1: Elsevier Inc.
AbstractThe current chromatographic approaches used in protein purification are not keeping pace with the increasing biopharmaceutical market demand. With the upstream improvements, the bottleneck shifted towards the downstream process. New approaches rely in Anything But Chromatography methodologies and revisiting former techniques with a bioprocess perspective. Protein crystallization and precipitation methods are already implemented in the downstream process of diverse therapeutic biological macromolecules, overcoming the current chromatographic bottlenecks. Promising work is being developed in order to implement crystallization and precipitation in the purification pipeline of high value therapeutic molecules. This review focuses in the role of these two methodologies in current industrial purification processes, and highlights their potential implementation in the purification pipeline of high value therapeutic molecules, overcoming chromatographic holdups.