323 research outputs found

    Complex Long-Term Catatonia

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    Monitoring biotransformations in polyamide fibres

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    The enzymatic hydrolysis of polyamide fibres yields amino and carboxylic groups. These groups can be found in solution treatments as polyamide monomers and soluble oligomers. The amino groups can also be found at the surface of the fibres as end group chains. In this paper we report two methods to quantify the formation of these groups as a result of the enzymatic action. Soluble amino groups can be quantified with 2,4,6-trinitrobenzenesulfonic acid (TNBS), which yields a coloured complex which can be determined spectrophotometrically. The amino groups on the fibre surface can be quantified by reaction with a wool reactive dye and determination of colour intensities after a dyeing procedure below the glass transition temperature of polyamide

    Kinetics of direct and substrate-mediated electron transfer of versatile peroxidase-modified graphite electrodes

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    Electron transfer (ET) of versatile peroxidase (VP) was studied in the bioelectrocatalytic reduction reaction of H2O2 at peroxidase- modified graphite electrodes to obtain additional information on the kinetic characteristics of this novel ligninolytic peroxidase. Rotating disk electrodes (RDE) experiments were performed at 0 V (vs. SCE) in two different buffers (tartrate buffer, pH 5.0; and citrate buffer, pH 3.0). From measurements of the mediated and mediatorless currents of H2O2 reduction at the RDE, the percentage of VP molecules involved in direct ET (≈55%) was calculated. The peroxidase-modified electrodes were used for determination of the donor substrates in RDE mode, and the results were interpreted in terms of catalytic efficiencies

    Protein micro- and nano-capsules for biomedical applications

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    Micro- and nano-scale systems have emerged as important tools for developing clinically useful drug delivery systems. In this tutorial review, we discuss the exploitation of biomacromolecules for this purpose, focusing on proteins, polypeptides, nucleic acids and polysaccharides and mixtures thereof as potential building blocks for novel drug delivery systems. We focus on the mechanisms of formation of micro- and nano-scale protein-based capsules and shells, as well as on the functionalization of such structures for use in targeted delivery of bioactive materials. We summarise existing methods for protein-based capsule synthesis and functionalization and highlight future challenges and opportunities for delivery strategies based on biomacromolecules.U.S. is grateful to Professor Aharon Gedanken, Chemistry Department, Bar-Ilan University, Israel, for his support and supervision during her PhD research work. G.J.L.B. is a Royal Society University Research Fellow at the Department of Chemistry, University of Cambridge and an Investigador FCT at the Instituto de Medicina Molecular, Lisboa. We thank Nuno Azoia assistance with the preparation of the figures. The authors thank the European Union Seventh Framework Programme (FP7/20072013) under grant agreement NMP4-LA-2009-228827 NANOFOL

    Molecular Typing, Virulence Traits and Antimicrobial Resistance of Diabetic Foot Staphylococci

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    Diabetes mellitus is a major chronic disease that continues to increase significantly. One of the most important and costly complications of diabetes are foot infections that may be colonized by pathogenic and antimicrobial resistant bacteria, harboring several virulence factors, that could impair its successful treatment. Staphylococcus aureus is one of the most prevalent isolate in diabetic foot infections, together with aerobes and anaerobes

    Thermo-alkali-stable catalases from newly isolated Bacillus sp. for the treatment and recycling of textile bleaching effluents

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    Three thermoalkaliphilic bacteria, which were grown at pH 9.3–10 and 60–65 °C were isolated out of a textile wastewater drain. The unknown micro-organisms were identified as thermoalkaliphilic Bacillus sp. Growth nditions were studied and catalase activities and stabilities compared. Catalases from Bacillus SF showed high stabilities at 60 °C and pH 9 (t1/2=38 h) and thus this strain was chosen for further investigations, such as electron microscopy, immobilization of catalase and hydrogen peroxide degradation studies. Degradation of hydrogen peroxide with an immobilized catalase from Bacillus SF enabled the reuse of the water for the dyeing process. In contrast, application of the free enzyme for treatment of bleaching effluents, caused interaction between the denaturated protein and the dye, resulting in reduced dye uptake, and a higher color difference of 1.3 ΔE* of dyed fabrics compared to 0.9 ΔE* when using the immobilized enzyme

    The effect of high-energy environments on the structure of laccase-polymerized poly(catechol)

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    The laccase polymerization of catechol was performed using different reactors namely a water bath (WB), an ultrasonic bath (US) and a high-pressure homogenizer (HPH). The total content of free OH and the MALDI-TOF spectra of polymers obtained demonstrated that reactions are favored in the presence of high-energy environments. Higher conversion yields and polymerization degrees (DP) were obtained after polymerization using US or HPH. Molecular dynamic simulation studies supported these findings by revealing a more open enzyme active site upon environments with high molecular agitation. The higher mass transport generated by US and HPH is the main feature responsible for a higher substrate accessibility to the enzyme which contributed to produce longer polymers.This study was supported by Chinese Government Scholarship under China Scholarship Council (No. 201606790036) and Chinese Foundation Key projects of governmental cooperation in international scientiïŹc and technological innovation (No. 2016 YFE0115700) and by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. Tarsila Castro thanks the senior position funded by the European Union through the European Regional Development Fund (ERDF) under the Competitiveness Operational Program (COP-A1.1.4-E-2015 nr.30/01.09.2016). Access to computing resources funded by the Project “Search-ON2: Revitalization of HPC infrastructure of UMinho” (NORTE-07-0162-FEDER-000086), cofundedbytheNorth Portugal RegionalOperationalProgramme (ON.2– O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF), is also gratefully acknowledged. Jennifer Noro also thanks to FCTFundação para a CiĂȘncia e a Tecnologia for funding her scholarship (SFRH/BD/121673/2016).info:eu-repo/semantics/publishedVersio

    Enzymatic removal of cellulose from cotton/polyester fabric blends

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    The production of light-weight polyester fabrics from a polyester/cotton blended fabric, by means of the enzymatic removal of the cellulosic part of the material, was investigated. The removal of cotton from the blended fabric yielded more than 80% of insoluble microfibrillar material by the combined action of high beating effects and cellulase hydrolysis.Other major features of this enzymatic process for converting cotton fibers into microfibrillar material are bath ratio, enzyme dosage and treatment time
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