249 research outputs found

    Simultaneous morphological transformation of metal salt and conformations of DNA in a bio-based ionic liquid

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    The extraordinary left handed conformation of DNA known as Z-DNA has attracted the attention of structural biologists due to its characteristic features such as its possible role in regulation of gene expression and genetic instability. There are number of physical parameters which can induce the conformational transformation of double helical B-DNA to Z-DNA. Among the various physical conditions, right-handed B-DNA can be transformed into left-handed Z-DNA in vitro at high salt concentrations or in vivo under physiological conditions. Herein DNA solubilized in a choline based ionic liquid namely choline formate was found to reduce Ag(I) salt into silver nanoparticles (AgNPs) with the size distribution of 10-20‚ÄĮnm. During the process, the interaction of DNA with the ionic liquid induces alteration in secondary structure of DNA (B-Z transition). The formation of the NPs was confirmed by UV-Vis spectrophotometer and Transmission Electron Microscopic (TEM) measurements, while the formation of Z-DNA was confirmed by circular dichroism (CD) spectroscopic measurements. Upon molecular docking studies, choline-formate was found to present different binding sites for its cation and anion and they promote torsions on DNA structure leading to possible changes in DNA three dimensional structures (B-Z transition).publishe

    Biosurfactants produced by Pseudomonas syringae pv tabaci: A versatile mixture with interesting emulsifying properties

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    In recent years, worldwide awareness about environmental concerns has led to an extensive searching for products of natural origin. Biosurfactants (BS), are an attractive alternative to the chemical counterparts. In these sense, this works evaluate for the first time the emulsifying and surface activity of biosurfactants produced by P. syringae pv. tabaci. Chemical characterization revealed that the produced BS extract mostly consisted in a mixture of syringopeptins and arthrofactins. Besides, this sample was able to reduce water surface tension up to 36.89 mN/m. This activity was improved by modifying conditions of pH, temperature and salinity. For instance, the surface tension was reduced up to 29 mN/m when using NaCl 5 % w/w. The BS also exhibited a high emulsifying activity, this being comparable or even superior to that of commercial bioemulsifiers such xanthan, tara and guar gums. A notorious emulsification index, close to 90 %, was exhibited by BS in coconut oil/water mixtures. Moreover, emulsifying activity resulted to be little affected by different operational conditions, thus retaining about 80 % of its emulsificant index in presence of 20 % w/w of NaCl at 80 ¬įC. These findings are indicative of the BS promising properties and its potential as additive in a variety of industrial applications.Fil: Haidar, Carla Nahir. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - Rosario. Instituto de Procesos Biotecnol√≥gicos y Qu√≠micos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioqu√≠micas y Farmac√©uticas. Instituto de Procesos Biotecnol√≥gicos y Qu√≠micos Rosario; ArgentinaFil: Pereira, Matheus M.. Universidade Tiradentes; BrasilFil: Lima, √Ālvaro S.. Universidade Tiradentes; BrasilFil: Nerli, Bibiana Beatriz. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - Rosario. Instituto de Procesos Biotecnol√≥gicos y Qu√≠micos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioqu√≠micas y Farmac√©uticas. Instituto de Procesos Biotecnol√≥gicos y Qu√≠micos Rosario; ArgentinaFil: Pellegrini Malpiedi, Luciana. Consejo Nacional de Investigaciones Cient√≠ficas y T√©cnicas. Centro Cient√≠fico Tecnol√≥gico Conicet - Rosario. Instituto de Procesos Biotecnol√≥gicos y Qu√≠micos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioqu√≠micas y Farmac√©uticas. Instituto de Procesos Biotecnol√≥gicos y Qu√≠micos Rosario; Argentin

    Multimodal ionic liquid-based chromatographic supports for an effective RNA purification

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    Nucleic acids have been considered interesting molecules to be used as biopharmaceuticals for the treatment of various diseases, in gene therapy strategies. In particular, RNA arises as the most promising approach because it does not require access to the nucleus of cells to exert its function; however, it is quite challenging due to its labile nature. To increase the possibility of translating RNA-based technology to clinical protocols, the biomanufacturing of RNAs has been intensively exploited in the last few years. However, the standard RNA purif ication processes remain time-consuming and present limitations regarding recovery yield and purity. This work describes the functionalization of chromatographic silica-based supports with four ionic liquids (ILs) composed of functional moieties that can promote distinct interactions with nucleic acids. After an initial screening to evaluate the binding and elution behavior of nucleic acids in the IL-based supports, SSi[C 3 C 3NH2 Im]Cl has shown to be the most promising for further purification assays. This support was studied for the RNA purification from different samples (clarified or more complex) and has shown to be highly effective, for all the conditions studied. Generally, it is here presented a new method for RNA isolation in a single step, using an IL-based chromatographic support, able to eliminate the usage of hazardous compounds often included in standard RNA extraction protocols.publishe

    Aqueous Biphasic Systems Comprising Natural Organic Acid-Derived Ionic Liquids

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    Despite the progress achieved by aqueous biphasic systems (ABSs) comprising ionic liquids (ILs) in extracting valuable proteins, the quest for bio‚Äźbased and protein‚Äźfriendly ILs continues. To address this need, this work uses natural organic acids as precursors in the synthesis of four ILs, namely tetrabutylammonium formate ([N4444][HCOO]), tetrabutylammonium acetate ([N4444][CH3COO]), tetrabutylphosphonium formate ([P4444][HCOO]), and tetrabutylphosphonium acetate ([P4444][CH3COO]). It is shown that ABSs can be prepared using all four organic acid‚Äźderived ILs paired with the salts potassium phosphate dibasic (K2HPO4) and tripotassium citrate (C6H5K3O7). According to the ABSs phase diagrams, [P4444]‚Äźbased ILs outperform their ammonium congeners in their ability to undergo liquid‚Äďliquid demixing in the presence of salts due to their lower hydrogen‚Äźbond acidity. However, deviations to the Hofmeister series were detected in the salts‚Äô effect, which may be related to the high charge density of the studied IL anions. As a proof of concept for their extraction potential, these ABSs were evaluated in extracting human transferrin, allowing extraction efficiencies of 100% and recovery yields ranging between 86 and 100%. To further disclose the molecular‚Äźlevel mechanisms behind the extraction of human transferrin, molecular docking studies were performed. Overall, the salting‚Äźout exerted by the salt is the main mechanism responsible for the complete extraction of human transferrin toward the IL‚Äźrich phase, whereas the recovery yield and protein‚Äźfriendly nature of these systems depend on specific ‚ÄúIL-transferrin‚ÄĚ interactions.publishe

    Distribution pattern of anurans from three mountain complexes in southeastern Brazil and their conservation implications

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    Biogeographic tools support spatial distribution pattern hypotheses and help to determine priority areas for conservation. Our aim was to verify biogeographic patterns for anurans in three mountain complexes in southeastern Brazil, as well as to discuss the status of species conservation recorded and the biogeographical units evaluated. We selected 16 areas distributed in the Serra da Mantiqueira complex, south of Serra do Espinhaço and Serra da Canastra. We used the occurrence (geographic coordinates) of each species in the localities to determine areas of endemism applying the Endemicity Analysis method. We also tested whether similarity between areas was explained by geographic distance (Multiple Regression on distance Matrices-MRM). The Serra do Itatiaia, Serra da Canastra, Plateau of Poços de Caldas and Serra do Cipó were the areas that presented the highest number of species restricted to them. Through the Endemicity Analysis, we identified four areas of endemism with higher scores. The MRM revealed that the geographic distance explained 41% of species dissimilarity between areas. Most of the endemic species from these areas have inaccurate conservation statuses (data deficient or unevaluated). These results highlight the need for greater research efforts towards understanding species restricted by distribution, as well as the priority in conserving these endemic areas

    Laccase activation in deep eutectic solvents

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    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 ¬ļC and -80 ¬ļC). 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 Internacionaliza√ß√£o (POCI), and by national funds (OE), through FCT/MCTES. Mariah L. Toledo acknowledges University of S√£o Paulo (Mobilidade internacional de dura√ß√£o 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 Coordena√ß√£o de Aperfei√ßoamento de Pessoal de N√≠vel Superior - Capes. Jo√£o P. A. Silva acknowledges the support of FAPESP (Funda√ß√£o de Amparo √† Pesquisa do Estado de S√£o Paulo-Process Number 2016/06683-0).publishe

    Tailoring the partitioning of proteins using ionic liquids as adjuvants in polymer-polymer aqueous biphasic systems

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    Aqueous biphasic systems (ABS) are promising for proteins purification; however, when dealing with samples comprising several proteins, the selectivity towards a target protein is difficult to achieve. In this work, the addition of ionic liquids (ILs) as adjuvants (5 and 10‚ÄĮwt%) in ABS composed of polyethyleneglycol (PEG) and Dextran was investigated to tailor proteins‚Äô partitioning between the coexisting phases. The liquid-liquid phase diagrams were determined at 298‚ÄĮK, followed by partition studies of three proteins (bovine serum albumin (BSA), immunoglobulin G (IgG), and cytochrome C (Cyt C)). Partition coefficients of IgG and BSA indicate the preference of both proteins to the dextran-rich phase, whereas Cyt C has no preferential partitioning between the phases. The addition of chloride-based ILs as adjuvants allows to increase or decrease the partition coefficients, thus tailoring the proteins partitioning between the phases. BSA partitioning essentially depends on the IL content in each phase, whereas Cyt C and IgG partitioning is ruled by the ILs chemical structure and established interactions. Molecular docking was carried out to address the ILs effect on the proteins partitioning, supporting experimental observations, while identifying the specific interactions occurring. The partition of each protein in polymer-salt ABS with ILs as adjuvants was determined, demonstrating the higher tailoring ability of polymer-polymer ABS when adding ILs. Finally, the partition of each protein in presence of the remaining ones was determined, as well as the selectivity of the studied systems to separate each pair of proteins, paving the way for their use in liquid-liquid chromatography.publishe

    Understanding mobility in networks

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    Motivated by the growing number of mobile devices capable of connecting and exchanging messages, we propose a methodology aiming to model and analyze node mobility in networks. We note that many existing solutions in the literature rely on topological measurements calculated directly on the graph of node contacts, aiming to capture the notion of the node's importance in terms of connectivity and mobility patterns beneficial for prototyping, design, and deployment of mobile networks. However, each measure has its specificity and fails to generalize the node importance notions that ultimately change over time. Unlike previous approaches, our methodology is based on a node embedding method that models and unveils the nodes' importance in mobility and connectivity patterns while preserving their spatial and temporal characteristics. We focus on a case study based on a trace of group meetings. The results show that our methodology provides a rich representation for extracting different mobility and connectivity patterns, which can be helpful for various applications and services in mobile networks

    Evaluation Rainfall Regime at the Hydroelectric Power Plant Toward Climate Change

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    The hydroelectric plants are first in the Brazilian energy matrix, so irregularities in the rainfall regime can affect the energy generation, thus evidencing the need to know the rainfall distribution in the studied area. This work aimed to evaluate possible analysis of the impacts of climate change on the rainfall regime in the Machadinho hydroelectric region. For the research development, the IPCC-AR5 pessimistic scenario was used, representing a scenario with a continuous population growth and high carbon dioxide emissions. From the historical series and organized projections, precipitation anomalies were calculated. Analyzing the difference between the average of the month and the climatological normal, it was inferred that the model used presented a positive trend for precipitation in the period from 2026 - 2100, projecting anomalies between 25 and 200 mm per month. A greater amplitude is observed in the precipitation of 2076-2100, indicating an increase in the occurrence of extreme events of precipitation, mainly in the spring period. Considering that the rains in the Machadinho hydroelectric region are increasing in the scenarios analyzed, the average water level in the reservoir of the plant tends to increase

    Synthesis and characterization of analogues of glycine-betaine ionic liquids and their use in the formation of aqueous biphasic systems

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    A series of novel analogues of glycine-betaine ionic liquids (AGB-ILs), viz. 1-(4-ethoxy-4-oxobutyl)-1-methylpyrrolidin-1-ium, N,N,N-tri(n-butyl)(4-ethoxy-4-oxobutyl)-1-phosphonium and N,N,N-trialkyl(4-ethoxy-4-oxobutyl)-1-aminium cations with ethyl, n-propyl and n-butyl alkyl chains, combined with the bromide anion, have been synthesized and characterized. Their synthesis and characterization by spectroscopic methods and elemental analysis is here reported. These ILs were further characterized in what concerns their thermal properties and ecotoxicity against Allvibrio fischeri, and compared with the commercial tetra(n-butyl)ammonium and tetra(n-butyl)phosphonium bromide. The novel AGB-ILs described in this work have low melting points, below 100 ¬įC, display high degradation temperatures (180‚Äď310 ¬įC), and low toxicity as shown by being harmless or practically harmless towards the marine bacteria Allvibrio fischeri. Finally, the ability of the synthesized AGB-ILs to form aqueous biphasic systems with potassium citrate/citric acid (at pH 7) was evaluated, and the respective ternary phase diagrams were determined. It is shown that the increase of the cation alkyl chain length facilitates the creation of ABS, and that phosphonium-based ILs present a slightly better separation performance in presence of aqueous solutions of the citrate-based salt.publishe
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