Oxidative DNA damage protection and repair by polyphenolic compounds in PC12 cells

Biological systems are frequently exposed to excessive reactive oxygen species, causing a disturbance in the cells natural antioxidant defence systems and resulting in damage to all biomolecules, including nucleic acids. In fact, oxidative DNA damage is described as the type of damage most likely to occur in neuronal cells. In this study, three polyphenolic compounds, luteolin, quercetin and rosmarinic acid, were investigated for their protective effects against oxidative DNA damage induced in PC12 cells, a neuronal cell model. Although luteolin and quercetin prevented the formation of strand breaks to a greater extent than rosmarinic acid, this last one presented the highest capacity to repair strand breaks formation. In addition, rosmarinic acid was the only compound tested that increased the repair of oxidized nucleotidic bases induced with the photosensitizer compound [R]-1-[(10-chloro-4-oxo-3-phenyl-4H-benzo[a]quinolizin-1-yl) carbonyl]-2-pyrrolidine- methanol (Ro 19-8022). The activity of repair enzymes was indicated by the in vitro base excision repair assay, using a cell-free extract obtained from cells previously treated with the compounds to incise DNA. The protective effect of rosmarinic acid was further confirmed by the increased expression of OGG1 repair gene, observed through real time RT-PCR. The data obtained is indicative that rosmarinic acid seems to act on the intracellular mechanisms responsible for DNA repair, rather than by a direct effect on reactive oxygen species scavenging, as deducted from the effects observed for luteolin and quercetin. Therefore, these results suggest the importance of these polyphenols, and in particular rosmarinic acid, as protectors of oxidative stress-induced DNA damage that commonly occurs in several pathological conditions, such as neurodegenerative diseases.Fundação para a Ciência e a Tecnologia (FCT) - bolsa SFRH/BD/17174/2004

Carotenoid production from microalgae: the portuguese scenario

Microalgae have an outstanding capacity to efficiently produce value-added compounds. They have been inspiring researchers worldwide to develop a blue biorefinery, supporting the development of the bioeconomy, tackling the environmental crisis, and mitigating the depletion of natural resources. In this review, the characteristics of the carotenoids produced by microalgae are presented and the downstream processes developed to recover and purify them are analyzed, considering their main applications. The ongoing activities and initiatives taking place in Portugal regarding not only research, but also industrialization under the blue biorefinery concept are also discussed. The situation reported here shows that new techniques must be developed to make microalgae production more competitive. Downstream pigment purification technologies must be developed as they may have a considerable impact on the economic viability of the process. Government incentives are needed to encourage a constructive interaction between academics and businesses in order to develop a biorefinery that focuses on high-grade chemicals.publishe

Distinct roles of salt cations and anions upon the salting-out of electro-positive albumin

Precipitation experiments of electro-positive albumin by the action of a wide number of salts, and at differentconcentrations, were performed at a constant temperature (25 °C). The pH range studied covered extreme acidicconditions up to hydronium concentrations where the dissociation of the protein carboxyl groups becomes no-ticeable. The time required for the clouding phenomenon to occur and the quantity of salted-out protein werealso ascertained. The results here reported show that the salt anion is the main salting-out species for the posi-tively charged protein, where their efficacy in salting-out albumin from aqueous solution increases in theorder: F−bCl−bBr−bNO3−bI−bSCN−~ ClO4−bSO42−. Although at extreme pH conditions the salt cationhas no significant influence on the protein salting-out, experiments performed at higher pH values, where thecarboxyl groups starts to dissociate, revealed a non-monotonic effect of the salt upon protein precipitation. Weinterpret this observation as a result of the presence of different protein forms, with which the salt cation partic-ipates in chemical equilibrium. Overall, the proteins salting-out phenomenon induced by salt can be rationalizedby a general mechanism driven by electrostatic interactions and chemical equilibrium concepts.publishe

Effects of two new di(hetero)arylamines on prevention of oxidative stress induced in two different biological models

We investigated the antioxidant properties of two new diarylamines from organic synthesis (MJQ1 and MJQ2), whose basic structure is similar to others, with reported antioxidant capacity, assessed by chemical tests, and biological activity against microorganisms. In this study we induced lipid peroxidation, in isolated rat liver mitochondria with ADP/Fe2+, and the diarylamine effects were examined by oxygen consumption and by TBARS method. The anti-peroxidative effect was maximal for MJQ1 at 50 nM (higher than the one reported for trolox) and for MJQ2 at 60 μM. At these same concentrations none of them depressed the transmembrane potential (ΔΨ) developed by mitochondria, neither the RCR nor the ADP/O ratio values. For 2-fold these concentrations both diarylamines were effective in the prevention of mitochondrial ΔΨ collapse observed on respiring mitochondria, with the TPP+ electrode, which means a stabilization action on mitochondrial inner membrane. The results obtained were confirmed in whole cells. The compounds did not show toxicity to the L929 cell line, evaluated by the MTT reducing test and clearly protected from lipid peroxidation, induced by the oxidant pair ascorbate/Fe2+, to the PC12 cell model, at the concentrations where maximal antioxidant effect was observed in mitochondria. The new diarylamines revealed as very good antioxidants at very low concentrations, both in mitochondria and in whole cells. The results suggest a specific action site, for MJQ2, at mitochondrial complex I level. We are further exploring other intracellular targets for these new compounds that seems very promising against pathologies where oxidative stress is involved.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/17174/2004 - JP

Nitrogen compounds prevent H9c2 myoblast oxidative stress-induced mitochondrial dysfunction and cell death

Oxidative stress has been connected to various forms of cardiovascular diseases. Previously, we have been investigating the potential of new nitrogen-containing synthetic compounds using a neuronal cell model and different oxidative stress conditions in order to elucidate their potential to ameliorate neurodegenerative diseases. Here, we intended to extend these initial studies and investigate the protective role of four of those new synthetic compounds (FMA4, FMA7, FMA762 and FMA796) against oxidative damage induced to H9c2 cardiomyoblasts by tert-butylhydroperoxide (t-BHP). The data indicates that FMA762 and FMA796 decrease t-BHP-induced cell death, as measured by both sulforhodamine B assay and nuclear chromatin condensation evaluation, at non-toxic concentrations. In addition, the two mentioned compounds inhibit intracellular signalling mechanisms leading to apoptotic cell death, namely those mediated by mitochondria, which was confirmed by their ability to overcome t-BHP-induced morphological changes in the mitochondrial network, loss of mitochondrial membrane potential, increased expression of the pro-apoptotic proteins p53, Bax and AIF and activation of caspases-3 and -9. Importantly, our results indicate that the compounds’ ROS scavenging ability plays a crucial role in the protection profile, as a significant decrease in t-BHP-induced oxidative stress occurred in their presence. Data obtained indicates that some of the test compounds may clearly prove valuable in a clinical context by diminishing cardiac injury associated to oxidative stress without any toxicity.Fundação para a Ciência e a Tecnologia (FCT) - Bolsa SFRH/BD/17174/2004, PTDC/QUI/ 64358/200

Modeling asphaltene precipitation in Algerian oilfields with the CPA EoS

One of the major flow assurance problems afflicting the oil industry is the asphaltene precipitation during the production, transportation and storage of oil. The precipitation of these heavy compounds is responsible for changes in crude oil properties, increases in oil viscosity, and formation of deposits that reduce oil production and disable equipment leading to significant operational costs. In Algeria, the deposition of asphaltene in res- ervoirs and pipelines is a severe problem. During production the depressurization of reservoir fluid and the variations of thermodynamic conditions create the need to frequently pig the lines and, in some cases, to inject solvents and dispersants to maintain the production. The understanding of the asphaltene behavior and the prediction of its deposition in flow conditions is crucial to implement appropriate strategies for the prevention or remediation, especially in the wellbore region. In this work we used the CPA EoS to describe the asphaltene phase envelope and predict the PT regions of stability for five Algerian live oils. The model provides a very good description of the experimental behavior of live oils without and with gas injection. The sensitivity to SARA analysis data and its effect on the asphaltene phase boundaries were also analyzed.BC Advanced Technologies Limited, Sonatrachpublishe

Laccase activation in deep eutectic solvents

The research on alternative solvents and co-solvents is a relevant aspect when envisioning the improvement of biocatalytic reactions. Among these solvents and co-solvents, deep eutectic solvents (DES) may be considered as customizable new reaction media for biocatalysis. Accordingly, in this work, sixteen DES aqueous solutions, as well as of the individual DES components at the same conditions have been investigated in laccase-catalyzed reactions. Cholinium- and betaine-based DES formed with polyols at different molar ratio and concentrations were evaluated. The results reported show that in presence of most DES the laccase activity is preserved and, with a particular DES, enhanced up to 200%. Molecular docking studies demonstrated that while most DES components establish hydrogen-bonds with the enzyme amino acids, those that establish stronger interactions with the enzyme (expressed by absolute values of docking affinity energies) lead to an enhanced laccase activity. Finally, the laccase stability was evaluated in additional tests under extreme storage temperatures (60 ºC and -80 ºC). Although no significant protection to high temperatures was afforded by DES, an enhanced laccase activity when stored at low temperatures was found, at least up to 20 days. Combining experimental results and molecular docking this work shows that DES can be designed as co-solvents to improve biocatalytic reactions.This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, FCT Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES and within the project POCI-01-0145-FEDER-031268 - funded by FEDER, through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI), and by national funds (OE), through FCT/MCTES. Mariah L. Toledo acknowledges University of São Paulo (Mobilidade internacional de duração 23especial). Ana P. M. Tavares acknowledges FCT for the Investigator Programme (IF/01634/2015). Matheus M. Pereira acknowledges the PhD grant (2740-13-3) and financial support from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Capes. João P. A. Silva acknowledges the support of FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo-Process Number 2016/06683-0).publishe

Quantum Link Prediction in Complex Networks

Predicting new links in physical, biological, social, or technological networks has a significant scientific and societal impact. Path-based link prediction methods utilize explicit counting of even and odd-length paths between nodes to quantify a score function and infer new or unobserved links. Here, we propose a quantum algorithm for path-based link prediction, QLP, using a controlled continuous-time quantum walk to encode even and odd path-based prediction scores. Through classical simulations on a few real networks, we confirm that the quantum walk scoring function performs similarly to other path-based link predictors. In a brief complexity analysis we identify the potential of our approach in uncovering a quantum speedup for path-based link prediction.Comment: Keywords: Complex Networks, Quantum Algorithms, Link Prediction, Social Networks, Protein-Protein Interaction Network

Integrated leaching and separation of metals using mixtures of organic acids and ionic liquids

In this work, the aqueous phase diagram for the mixture of the hydrophilic tributyltetradecyl phosphonium ([P44414]Cl) ionic liquid with acetic acid (CH3COOH) is determined, and the temperature dependency of the biphasic region established. Molecular dynamic simulations of the [P44414]Cl + CH3COOH + H2O system indicate that the occurrence of a closed "type 0" biphasic regime is due to a "washing-out" phenomenon upon addition of water, resulting in solvophobic segregation of the [P44414]Cl. The solubility of various metal oxides in the anhydrous [P44414]Cl + CH3COOH system was determined, with the system presenting a good selectivity for CoO. Integration of the separation step was demonstrated through the addition of water, yielding a biphasic regime. Finally, the [P44414]Cl + CH3COOH system was applied to the treatment of real waste, NiMH battery black mass, being shown that it allows an efficient separation of Co(II) from Ni(II), Fe(III) and the lanthanides in a single leaching and separation step.publishe

Pretreatment of plastic waste: Removal of colorants from hdpe using biosolvents

UIDB/50011/2020 UIDP/50011/2020 CA18220, 2020.00647.CEECIND UIDB/50006/2020 UIDP/50006/2020Plastics recycling remains a challenge due to the relatively low quality of the recycled material, since most of the developed recycling processes cannot deal with the additives present in the plastic matrix, so the recycled products end up in lower-grade applications. The application of volatile organic solvents for additives removal is the preferred choice. In this study, pretreatment of plastic packaging waste to remove additives using biosolvents was investigated. The plastic waste used was high-density polyethylene (HDPE) with blue and orange colorants (pigment and/or dye). The first step was to identify the type of colorants present in the HDPE, and we found that both plastics presented only one colorant that was actually a pigment. Then, limonene, a renewable solvent, was used to solubilize HDPE. After HDPE dissolution, a wide range of alcohols (mono-, di-, and tri-alcohols) was evaluated as antisolvents in order to selectively precipitate the polymer and maximize its purity. The use of limonene as solvent for plastic dissolution, in combination with poly-alcohols with an intermediate alkyl chain length and a large number of hydroxyl (OH) groups, was found to work best as an antisolvent (1,2,3-propanetriol and 1,2,4-butanetriol), leading to a removal of up to 94% and 100% of the blue and orange pigments, respectively. Finally, three cycles of extraction were carried out, proving the capability of the solvent and antisolvent to be recovered and reused, ensuring the economic viability and sustainability of the process. This pretreatment provides a secondary source of raw materials and revenue for the recycling process, which may lead to an increase in the quality of recycled polymers, contributing to the development of an economical and sustainable recycling process.publishersversionpublishe