Glutaraldehyde in bio-catalysts design: a useful crosslinker and a versatile tool in enzyme immobilization

Glutaraldehyde is one of the most widely used reagents in the design of biocatalysts. It is a powerful crosslinker, able to react with itself, with the advantages that this may bring forth. In this review, we intend to give a general vision of its potential and the precautions that must be taken when using this effective reagent. First, the chemistry of the glutaraldehyde/amino reaction will be commented upon. This reaction is still not fully clarified, but it seems to be based on the formation of 6-membered heterocycles formed by 5 C and one O. Then, we will discuss the production of intra- and inter-molecular enzyme crosslinks (increasing enzyme rigidity or preventing subunit dissociation in multimeric enzymes). Special emphasis will be placed on the preparation of cross-linked enzyme aggregates (CLEAs), mainly in enzymes that have low density of surface reactive groups and, therefore, may be problematic to obtain a final solid catalyst. Next, we will comment on the uses of glutaraldehyde in enzymes previously immobilized on supports. First, the treatment of enzymes immobilized on supports that cannot react with glutaraldehyde (only inter and intramolecular cross-linkings will be possible) to prevent enzyme leakage and obtain some enzyme stabilization via cross-linking. Second, the cross-linking of enzymes adsorbed on aminated supports, where together with other reactions enzyme/support crosslinking is also possible; the enzyme is incorporated into the support. Finally, we will present the use of aminated supports preactivated with glutaraldehyde. Optimal glutaraldehyde modifications will be discussed in each specific case (one or two glutaraldehyde molecules for amino group in the support and/or the protein). Using preactivated supports, the heterofunctional nature of the supports will be highlighted, with the drawbacks and advantages that the heterofunctionality may have. Particular attention will be paid to the control of the first event that causes the immobilization depending on the experimental conditions to alter the enzyme orientation regarding the support surface. Thus, glutaraldehyde, an apparently old fashioned reactive, remains the most widely used and with broadest application possibilities among the compounds used for the design of biocatalyst

Strategies for the one-step immobilization–purification of enzymes as industrial biocatalysts

In this review, we detail the efforts performed to couple the purification and the immobilization of industrial enzymes in a single step. The use of antibodies, the development of specific domains with affinity for some specific supports will be revised. Moreover, we will discuss the use of domains that increase the affinity for standard matrices (ionic exchangers, silicates). We will show how the control of the immobilization conditions may convert some unspecific supports in largely specific ones. The development of tailor-made heterofunctional supports as a tool to immobilize–stabilize–purify some proteins will be discussed in deep, using low concentration of adsorbent groups and a dense layer of groups able to give an intense multipoint covalent attachment. The final coupling of mutagenesis and tailor made supports will be the last part of the review.This work has been supported by grant CTQ2013-41507-R from Spanish MINECO, grant no.1102-489-25428 from COLCIENCIAS and Universidad Industrial de Santander (VIE-UIS Research Program) (Colombia) and CNPq grant 403505/2013-5 (Brazil). A. Berenguer-Murcia thanks the Spanish MINECO for a Ramon y Cajal fellowship (RyC-2009-03813)

Heterofunctional Supports in Enzyme Immobilization: From Traditional Immobilization Protocols to Opportunities in Tuning Enzyme Properties

A heterofunctional support for enzyme immobilization may be defined as that which possesses several distinct functionalities on its surface able to interact with a protein. We will focus on those supports in which a final covalent attachment between the enzyme and the support is achieved. Heterofunctionality sometimes has been featured in very old immobilization techniques, even though in many instances it has been overlooked, giving rise to some misunderstandings. In this respect, glutaraldehyde-activated supports are the oldest multifunctional supports. Their matrix has primary amino groups, the hydrophobic glutaraldehyde chain, and can covalently react with the primary amino groups of the enzyme. Thus, immobilization may start (first event of the immobilization) via different causes and may involve different positions of the enzyme surface depending on the activation degree and immobilization conditions. Other “classical” heterofunctional supports are epoxy commercial supports consisting of reactive covalent epoxy groups on a hydrophobic matrix. Immobilization is performed at high ionic strength to permit protein adsorption, so that covalent attachment may take place at a later stage. Starting from these old immobilization techniques, tailor-made heterofunctional supports have been designed to permit a stricter control of the enzyme immobilization process. The requirement is to find conditions where the main covalent reactive moieties may have very low reactivity toward the enzyme. In this Review we will discuss the suitable properties of the groups able to give the covalent attachment (intending a multipoint covalent attachment), and the groups able to produce the first enzyme adsorption on the support. Prospects, limitations, and likely pathways for the evolution (e.g., coupling of site-directed mutagenesis and thiol heterofunctional supports of enzyme immobilization on heterofunctional supports) will be discussed in this Review.This work has been supported by Grant CTQ2009-07568 from Spanish Ministerio de Ciencia e Innovacion, Grant No.1102-489-25428 from COLCIENCIAS and Universidad Industrial de Santander (VIE-UIS Research Program) and CNPq and FAPERGS (Brazil). Á.B.-M. thanks the Spanish Ministerio de Ciencia e Innovacion for a Ramon y Cajal fellowship (RyC-2009-03813)

Análise multimodal da morte dos jornalistas na cobertura da tragédia da Chapecoense nos sites da RBS TV e do Foxsports.com.br

This article defends the use of multimodal framework analysis to first understand the coverage of the LaMia flight crash that caused the death of 71 people on November 29th, 2016 in Colombia and, later, in particular, to analyze the news about the loss of 20 Brazilian journalists who were on board the plane. For this, an analysis of the different communicative modes of the news, image, narrative and frame, was established to understand the constitution of the news on the websites of RBS TV and Foxsports.com.br. When analyzing 182 news in a period of 13 days, the results achieved confirmed an appreciation of the rhetoric of solidarity with Chapecoense – and a lower production of news content about professionals from competing journalistc organization, even in an exceptional case that resulted in the death of 20 journalists from eight media.Este artigo defende a utilização da análise de enquadramento multimodal para compreender, primeiramente, a cobertura da queda do voo da LaMia que causou a morte de 71 pessoas no dia 29 de novembro de 2016 na Colômbia e, posteriormente, em particular, analisar o noticiário sobre a perda de 20 jornalistas brasileiros que estavam a bordo do avião. Para isso, estabeleceu-se uma análise dos diferentes modos comunicativos da notícia – imagem, narrativa e frame –, para entender a constituição do noticiário nos sites da RBS TV e do Foxsports.com.br. Ao analisar 182 notícias em um período de 13 dias, os resultados alcançados confirmaram a valorização da retórica de solidariedade à Chapecoense e uma menor produção de conteúdo noticioso sobre profissionais de organizações jornalísticas concorrentes, mesmo em um caso excepcional que resultou na morte de 20 jornalistas de oito meios de comunicação

EVENTOS PLUVIAIS EXTREMOS EM BRASÍLIA-DF NO PERÍODO 1963-2019

O objetivo deste trabalho é apresentar resultados da análise de uma série histórica de precipitação pluvial de Brasília (DF), referente ao período 1963-2019, a fim de identificar eventos pluviais extremos, sua frequência, tempo de retorno e tendências. Todos os episódios de chuva diária igual ou superior a 1 mm foram considerados e classificados por classes de precipitação pluvial. A definição do limiar diário para identificação de eventos pluviais extremos foi obtida a partir de recomendações do Expert Team on Climate Change Detection Monitoring and Indices, que indica o Percentil 99 como parâmetro. A avaliação de tendências, na ocorrência de eventos pluviais extremos, no período estudado foi realizada a partir da aplicação do teste de tendência Mann-Kendall. Os resultados mostram que ao longo do período estudado ocorreram 6.159 episódios de precipitação em Brasília. A análise do Percentil 99 da série resultou no valor de 72,3 mm/dia, a partir do qual foram identificados os eventos pluviais extremos. Ao longo dos 57 anos, ocorreram 62 episódios dessa natureza, com tempo de retorno de 334,7 dias ou 0,94 ano. Não foram detectadas tendências com significância estatística na série de dados de precipitação pluvial no período analisado. Ressalva-se que a contribuição apresentada retrata o que ocorre na estação meteorológica de Brasília, localizada na área planejada da capital federal – o Plano Piloto, e que a metodologia empregada poderia ser aplicada sobre dados de estações meteorológicas localizadas em outras Regiões Administrativas do DF, a fim de melhor retratar o conjunto regional

Spatial variability of apparent electrical conductivity and physicochemical attributes of the soil

The apparent electrical conductivity has been an attribute widely used in studies of spatial variability, due to its high correlation with other soil attributes and because it is an attribute that represents the variability of an area in a quick, easy and low-cost way. The objective of this study was to evaluate the relationship between the spatial variability of apparent electrical conductivity with physicochemical attributes of an Eutrophic Red Oxisol located in Maracaju, state of Mato Grosso do Sul, Brazil, for determining specific soil management zones. We analyzed apparent electrical conductivity attributes (ECa 2, 7 and 15 kHz), contents of potassium, cation exchange capacity, clay, base saturation and organic matter content. ECa was measured with the Profiler EMP-400 crossing the entire area in 0.45 m spaced lines. Soil samples were collected in the 0.000.20 m layer, with a total of 216 samples in an area of 70 ha. Statistical and geostatistical analyses were performed by SAS and GS+ software. The apparent electrical conductivity (ECa) was presented as an important tool to identify specific management zones showing data variability between low and medium zones. The attributes that had higher correlation with apparent electrical conductivity were potassium and clay

Neuromuscular taping does not change fibularis longus latency time and postural sway

Ankle sprains are a common injury and fibularis longus plays an important role improving functional stability. Neuromuscular tape seems to improve muscle force, although little is known regarding its effect on latency time.info:eu-repo/semantics/publishedVersio

Transporte urbano: o papel do BNDES no apoio à solução dos principais gargalos de mobilidade

Ao fazermos uma avaliação da atuação do BNDES no financiamento ao setor de transporte urbano de passageiros nas últimas três décadas, podemos constatar que, ainda que em diversos aspectos os avanços tenham sido expressivos e nossa participação nesses avanços seja reconhecida, as carências continuam gigantescas. Pode-se atribuir boa parte desse passivo às pressões decorrentes de um crescimento demográfico acelerado na segunda metade do século XX, o que foi agravado por um processo de urbanização que não foi devidamente acompanhado do aprimoramento dos instrumentos de gestão urbana e nem da redistribuição dos recursos financeiros necessários para que os municípios fizessem os investimentos em infraestrutura, o que só ocorreu com a Constituição de 1988. Contudo, não podemos omitir a visão imediatista dos gestores, relegando ao segundo plano de prioridades os projetos e investimentos de longo prazo, como é mostrado nesse artigo em relação ao transporte coletivo de passageiros.By analyzing the performance of the BNDES’ financing in the urban passenger transport sector over the last three decades, we are able to state that, even though progress has been expressive in several aspects and the Bank’s participation in such progress is recognized, gaps remain colossal. A large part of this gap can be attributed to pressure resulting from the accelerated demographic growth throughout the second half of the 20th century. This was intensified by urbanization that was not duly accompanied by improvements in urban management instruments or the redistribution of financial resources. Such funding was needed by municipalities to invest in infrastructure, which only came about with the Constitution of 1988. Nevertheless, we cannot omit the immediatist view of managers, who place longterm investment projects low on the list of priorities when it comes to collective passenger transport

IL-6 treatment increases the survival of retinal ganglion cells in vitro: The role of adenosine A1 receptor

AbstractIL-6 is a pleiotropic cytokine classically denominated pro-inflammatory. It has been already demonstrated that IL-6 can increase the survival of retinal ganglion cells (RGC) in culture. In this work, we show that the trophic effect of IL-6 is mediated by adenosine receptor (A1R) activation. The neutralization of extracellular BDNF abolished the IL-6 effect and the treatment with IL-6 and CHA (an agonist of A1R) modulated BDNF expression as well as pCREB and pTrkB levels

Galacto-oligosaccharides production during lactose hydrolysis by free Aspergillus oryzae β-galactosidase and immobilized on magnetic polysiloxane-polyvinyl alcohol

The synthesis of galacto-oligosaccharides (GOS) by the action of Aspergillus oryzae β-galactosidase free and immobilized on magnetic polysiloxane-polyvinyl alcohol (mPOS-PVA) was studied. A maximum GOS concentration of 26% (w/v) of total sugars was achieved at near 55% lactose conversion from 50%, w/v lactose solution at pH 4.5 and 40 °C. Trisaccharides accounted for more than 81% of the total GOS produced. GOS formation was not considerably affected by pH and temperature. The concentrations of glucose and galactose encountered near maximum GOS concentration greatly inhibited the reactions and reduced GOS yield. GOS formation was not affected by enzyme immobilization in the mPOS-PVA matrix, indicating the absence of diffusional limitations in the enzyme carrier. Furthermore, this water insoluble magnetic derivative was reutilized 10-times and retained about 84% of the initial activity. In addition, the kinetic parameters for various initial lactose concentrations were determined and compared for the free and immobilized enzyme.David F. M. Neri gratefully acknowledges support by the Programme Alpan, the European Union Programme of High Level Scholarships for Latin America (Scholarship No. E05D057787BR). Luiz B. Carvalho Jr. is recipient of a scholarship of the Brazilian National Research Council (CNPq)