Plant cell wall architecture guided design of CBM3-GH11 chimeras with enhanced xylanase activity using a tandem repeat left-handed β-3-prism scaffold.

Effective use of plant biomass as an abundant and renewable feedstock for biofuel production and biorefinery requires efficient enzymatic mobilization of cell wall polymers. Knowledge of plant cell wall composition and architecture has been exploited to develop novel multifunctional enzymes with improved activity against lignocellulose, where a left-handed β-3-prism synthetic scaffold (BeSS) was designed for insertion of multiple protein domains at the prism vertices. This allowed construction of a series of chimeras fusing variable numbers of a GH11 β-endo-1,4-xylanase and the CipA-CBM3 with defined distances and constrained relative orientations between catalytic domains. The cellulose binding and endoxylanase activities of all chimeras were maintained. Activity against lignocellulose substrates revealed a rapid 1.6- to 3-fold increase in total reducing saccharide release and increased levels of all major oligosaccharides as measured by polysaccharide analysis using carbohydrate gel electrophoresis (PACE). A construct with CBM3 and GH11 domains inserted in the same prism vertex showed highest activity, demonstrating interdomain geometry rather than number of catalytic sites is important for optimized chimera design. These results confirm that the BeSS concept is robust and can be successfully applied to the construction of multifunctional chimeras, which expands the possibilities for knowledge-based protein design

UM OLHAR TEÓRICO-METODOLÓGICO SOBRE O CONCEITO DE AVALIAÇÃO DE APRENDIZAGEM EM TEMPO DE PANDEMIA

The Covid-19 pandemic revealed a series of intrinsic issues of the education landscape. In this article, we present the questions that refer to the assessment of learning. We discuss these issues from a theoretical-methodological perspective in the light of the theoretical constructs of the anthropological theory of the didactic and of the epistemological dimension of the concept of assessment and from these reflections, analyses, and discussions, we propose an assessment model. In the process of investigating the feasibility of the model, we tested it in an experimentation phase in a degree and a bachelor’s degree in chemistry at the Federal University of Technology of Paraná, Pato Branco campus. The results of this experiment presented elements that enable the continuity of our investigationA pandemia da Covid-19 descortinou uma série de questões intrínsecas em relação ao cenário da educação. Neste artigo, apresentamos as questões que se referem à avaliação de aprendizagem. Discutimos estas questões a partir de um olhar teórico-metodológico à luz dos constructos teóricos da Teoria Antropológica do Didático e da dimensão epistemológica do conceito de avaliação. Diante destas reflexões, análises e discussões, propomos um modelo de avaliação. Em um processo de investigação da viabilidade deste modelo avaliativo, atestamos o mesmo em uma fase de experimentação em um curso de licenciatura e bacharelado em Química da Universidade Tecnológica Federal de Paraná, campus Pato Branco. Os resultados desta experimentação apresentaram elementos que viabilizam a continuidade da nossa investigação, como por exemplo, o estreitamento da relação aluno-professorsaber durante a fase de experimentação, bem como a necessidade de estudo e pesquisa de forma a otimizar o tempo de aplicação

Análise do tempo e dimensão epistemológica do saber: limite de uma função real

Este artigo apresenta o resultado de parte de uma pesquisa de pós-doutorado que se refere a construção de uma linha do tempo a respeito das primeiras ideias do objeto matemático Limites de Funções de uma Variável Real, do século V a.C. com os paradoxos de Zenão até o século XIX d.C. com Louis-Augustin Cauchy (1789-1857) e Karl Weierstrass (1815-1897), cujo período envolve um estágio inicial, intermediário e formal do conceito. A partir destes relatos, o objetivo específico é construir um mapa epistemológico deste saber, englobando aspectos históricos e filosóficos, a fim de responder algumas questões referentes a dimensão epistemológica: Qual a gênese do saber? Quais os conhecimentos envolvidos na construção deste saber? Acredita-se que as respostas a essas questões serão de fundamental importância tanto para o pesquisador em didática da matemática, como para o professor de matemática

Antimicrobial activity of Agave sisalana

This study was carried out to evaluate the antimicrobial activity of extracts of the leaves and leaf waste discarded in the process of obtaining the hard fibers of Agave sisalana. The antimicrobial activity was determined by the paper disk diffusion method using Gram-positive and Gram-negative bacteria (nonresistant and resistant to antibiotics) and a fungus. The hydroalcoholic extract obtained from leaves and from sisal waste showed significant inhibition of Candida albicans, on the other hand, it was inactive against three strains of Staphylococcus aureus, two strains of Escherichia coli, a strain ofMicrococcus luteus, Bacillus cereus, Pseudomonas aeruginosa and Salmonella choleraesuis. The methanol extract of leaves showed weaker reduction in the inhibitory action of C. albicans when compared with the above extracts, and it was also inert against the other microorganisms tested

ANÁLISE EPISTEMOLÓGICA DE TEORIA DOS NÚMEROS E CRIPTOGRAFIA: IMPORTÂNCIA DESSAS ÁREAS NOS CURRÍCULOS DE LICENCIATURA EM MATEMÁTICA

Esta pesquisa de cunho teórico-qualitativo apresenta os resultados de uma análise epistemológica de Teoria dos Números e Criptografia e evidencia a importância dos saberes/conhecimentos dessas áreas nos currículos dos cursos de Licenciatura em Matemática e nos currículos da Escola Básica. A pesquisa surgiu a partir de inquietações referentes à própria prática docente e, também, de relatos da comunidade científica incentivando um maior número de pesquisas na área de Educação Matemática em Teoria dos Números e a associação deste saber às aplicações em Criptografia. Diante deste fato, procuramos responder à seguinte questão de pesquisa: Por que Criptografia é um contexto significativo em Teoria dos Números para os currículos do curso de Licenciatura em Matemática? Para responder nossa questão de pesquisa, valemo-nos de alguns constructos da Teoria Antropológica do Didático e da dimensão epistemológica de um problema didático. Os resultados das pesquisas realizadas mostram que as respostas a essa questão são de fundamental importância tanto para o pesquisador em Didática da Matemática, como para o professor de Matemática

Peroxisomal APX knockdown triggers antioxidant mechanisms favourable for coping with high photorespiratory H2O2 induced by CAT deficiency in rice

The physiological role of peroxisomal ascorbate peroxidases (pAPX) is unknown; therefore, we utilized pAPX4 knockdown rice and catalase (CAT) inhibition to assess its role in CAT compensation under high photorespiration. pAPX4 knockdown induced co-suppression in the expression of pAPX3. The rice mutants exhibited metabolic changes such as lower CAT and glycolate oxidase (GO) activities and reduced glyoxylate content; however, APX activity was not altered. CAT inhibition triggered different changes in the expression of CAT, APX and glutathione peroxidase (GPX) isoforms between non-transformed (NT) and silenced plants. These responses were associated with alterations in APX, GPX and GO activities, suggesting redox homeostasis differences. The glutathione oxidation-reduction states were modulated differently in mutants, and the ascorbate redox state was greatly affected in both genotypes. The pAPX suffered less oxidative stress and photosystem II (PSII) damage and displayed higher photosynthesis than the NT plants. The improved acclimation exhibited by the pAPX plants was indicated by lower H2O2 accumulation, which was associated with lower GO activity and glyoxylate content. The suppression of both pAPXs and/or its downstream metabolic and molecular effects may trigger favourable antioxidant and compensatory mechanisms to cope with CAT deficiency. This physiological acclimation may involve signalling by peroxisomal H2O2, which minimized the photorespiration.</p

A scanning electron microscopic study of hypercementosis

The purpose of this study was to evaluate morphological characteristics of teeth with hypercementosis that are relevant to endodontic practice. Twenty-eight extracted teeth with hypercementosis had their root apexes analyzed by scanning electron microscopy (SEM). The teeth were divided according to tooth groups and type of hypercementosis. The following aspects were examined under SEM: the contour and regularity of the root surface; presence of resorption; presence and number of apical foramina, and the diameter of the main foramen. The progression of club shape hypercementosis was directly associated with the presence of foramina and apical foramen obstruction. Cases of focal hypercementosis presented foramina on the surface, even when sidelong located in the root. Circular cementum hyperplasia form was present in 2 out of 3 residual roots, which was the highest proportion among the tooth types. The detection of a large number of foramina in the apical third of teeth with hypercementosis or even the possible existence of apical foramen obliteration contributes to understand the difficulties faced during endodontic treatment of these cases

Cervical cancer screening: target age bracket, screening frequency and screening method: review of recent evidence and comparison with the Portuguese performance indicator

Esta revisão teve por objetivo avaliar a força de evidência do indicador de desempenho português relativo ao rastreio do Câncer do Colo do Útero (CCU): (1) limites etários das mulheres da população geral que o devem realizar, a (2) periodicidade com que deve ser realizado e (3) qual o melhor exame de rastreio. Foram pesquisados os seguintes termos MeSH: vaginal smears, age groups, periodicity, methods, uterine cervical cancer. Foram excluídos os artigos que não abordavam o objetivo da investigação ou que não fossem redigidos em Inglês, Português ou Espanhol. Para interpretar os artigos selecionados foi utilizada a classificação SORT. Foram encontrados 197 artigos, dos quais seleccionados 9: 1 revisão sistemática (RS), 1 estudo clínico controlado aleatorizado, 2 estudos observacionais retrospectivos e 5 normas de orientação clínica (NOC). Os autores optaram por incluir nesta revisão mais 4 NOCs e 2 RSs por considerarem ser relevantes para a população Portuguesa, apesar de não resultarem da pesquisa efectuada. Os estudos sugerem realização do rastreio entre os 21 e 25 até aos 65 anos, com uma periodicidade trienal usando a citologia convencional. Existe ainda controvérsia no que toca aos 3 objetivos deste artigo (limites etários, frequência e método).The scope of this review was to assess the strength of evidence of Portuguese performance indicators on Cervical Cancer screening: (1) age group of the women that should be screened for cervical cancer; (2) frequency of screening; and (3) the best method for screening. The following MeSH terms were searched: vaginal smears, age groups, periodicity, methods, uterine cervical cancer. Articles not reflecting the study objectives or not available in English, Portuguese or Spanish were excluded. The SORT classification was used to rate the articles selected.Of the 197 articles found, 9 that met all study criteria were selected for inclusion in this review. These included 1 systematic review, 1 randomized controlled clinical trial, 2 retrospective studies and 5 clinical guidelines. The authors also chose to include 4 clinical guidelines and two systematic reviews relevant to the Portuguese population even though they did not appear in the initial search of the literature. The studies suggest screening women between the ages of 21 to 25 years and 65 years of age, once every three years using conventional cytology. There is still controversy regarding the three objectives of this study (target age bracket, screening frequency and screening method)