Analysis of biological materials by the atomic absorption spectrophotometry. I. Determination of total copper, iron and zinc in chicken livers

São apresentados os resultados obtidos na determinação do cobre, ferro e zinco, em fígado seco de frangos de corte da linhagem Shaver-Starbro, utilizando a espectrofotometria de absorção atômica como método analítico. Também são analisadas as possibilidades de estudo do metabolismo destes elementos em aves, sendo indicados alguns campos de estudo do metabolismo mineral em que as aves se prestam admiravelmente à experimentação. Os valores encontrados nos fígados analisados (expressos em ppm no tecido seco), foram 14,4 ± 0,85 ppm para o cobre; 283,3 ± 19,78 ppm para o ferro e 130,4 ± 4,21 ppm para o zinco. Estes valores estão dentro dos limites indicados na escassa literatura existente a respeito. O método utilizado foi controlado para a verificação da ocorrência de interferências, de perdas, contaminação operacional e reprodutibilidade analítica, pelas provas do erro de duplicatas e de recuperação dos três elementos, na presença e na ausência de matéria orgânica. Tais provas forneceram resultados significativos, sendo que a recuperação dos três elementos na ausência de matéria orgânica foi de 101,3% para o cobre, 102,9% para o ferro e 99,0% para o zinco; na presença de matéria orgânica os resultados foram: 92,9%, 97,7% e 98,0%, respectivamente. Não foi verificado ocorrerem interferências por parte de outros elementos presentes na cinza em grande quantidade, como o sódio, o potássio, o cálcio e o fósforo. A prova do erro de duplicatas indicou grande uniformidade dos resultados obtidos. A análise dos elementos presentes em tecidos e líquidos biológicos por absorção atômica se recomenda pela versatilidade, sensibilidade e comodidade para o manuseio de grande número de amostras e, principalmente, pela eliminação dos métodos de fracionamento dos componentes da mistura.Total copper, iron and zinc contents of male Shaver-Starbro pullet chicken livers were determined by atomic absorption spectrophotometry. In applying this method to dry ashed samples of liver tissue from 32 normal animals (1,34 mean body weight) the following values were obtained: 14,4 ± 0,85 for copper, 283,3 ± 19,78 for iron and 130,4 ± 4,21 for zinc (mean ± standard deviation ppm refered to tissue dry weight). Recovery tests were carried out to check the occurrence of metal interferences and contamination as well as analytical losses. Very good recoveries were obtained both in the absence of organic matter (101,3% for Cu, 102,9% for Fe and 99,0% for Zn) and in the presence of chicken powder (92,9% for Cu, 97,7% for Fe and 98,0% por Zn). The results of these tests excluded the eventual contamination of the samples, glassware and reagents used. There were no evidences of any spectral interference by other elements normally present in large amounts in the ashes, such as, sodium, potassium, calcium and phosphorus. Duplicate error of analysis indicated the good reproducibility of the method. Atomic absorption spectrophotometry quantitative analysis of the metalic elements occurring in animal tissues and body fluids is recommended in view of its sensitivity, versatility and convenience. The advantages have been emphasized particularly for surveys on trace elements deficiences occurring in bovine and other animal species, which requires a convenient handling of large number of samples. The method offers, even so, the advantage of a direct analytical tool, free of troublesome and time consuming fractionation steps. The simplicity of the procedure and the reproducibility and reliability of the results obtained lead to the adaption of this method for analytical studies of bovine and avian mineral metabolism undertaken in this laboratory

Eficiência energética e realização de pré-diagnóstico energético em instituições de ensino de João Monlevade – MG

This paper aims to disseminate knowledge about energy efficiency to students of educational institutions in the municipality of João Monlevade in the state of Minas Gerais. Thus, the project aimed to propagate educational practices related to the efficient use of electric energy, combating energy wastage and consequently promoting the conservation of natural resources and reducing the impact of the cost of energy on the family budget of participants and schools. . Thus, the project was developed with approximately 144 children, from the first to fifth year of elementary school, who were approached through playful games. During this process, an energy pre-diagnosis was performed in one of the partner schools, in order to present the main errors regarding energy use and to suggest effective and simple actions to minimize them. . In addition, through research conducted at the beginning and end of the project with the participants, it was possible to verify that the promotion of the activities corresponded satisfactorily to the objectives of the project, since before the execution only 6% of the students were aware of the subject, increasing to 86% after the promotion. In this way, it is concluded that, the development of projects of this type contributes in the formation of agents promoting the fight against the waste of electric energy. All this, through simple actions that promote the conservation of electric energy without reducing the quality of life. It is also emphasized that this type of proposal also serves as support and motivation in the search for knowledge and socioeconomic and sustainable development of the country.El presente trabajo se propone diseminar conocimientos sobre eficiencia energética a estudiantes de instituciones de enseñanza en el municipio de João Monlevade en el estado de Minas Gerais. Por lo tanto, el proyecto tuvo como objetivo propagar prácticas educativas relacionadas con el aprovechamiento eficiente de la energía eléctrica, combatiendo el desperdicio de energía y promoviendo por consiguiente la conservación de recursos naturales y la disminución del impacto del costo de la energía en el presupuesto familiar de los participantes y de las escuelas. Así, el proyecto fue desarrollado con aproximadamente 144 niños, de primer a quinto año de la enseñanza fundamental, que fueron abordados por medio de juegos lúdicos. Durante este proceso, un pre-diagnóstico energético fue realizado en una de las escuelas asociadas, con el propósito de presentar los principales errores en relación al uso de energía y sugerir acciones efectivas y simples para minimizarlos. Además, mediante investigación realizada al inicio y al final del proyecto con los participantes, fue posible constatar que la promoción de las actividades correspondió satisfactoriamente a los objetivos del proyecto, ya que antes de la ejecución sólo el 6% de los alumnos tenían conocimiento del tema, 86% después de la promoción. De esta forma, se concluye que, que el desarrollo de proyectos de este tipo contribuye en la formación de agentes promotores del combate al desperdicio de energía eléctrica. Todo ello, a través de acciones simples que promueven la conservación de la energía eléctrica sin la disminución de la calidad de vida. Se destaca también que este tipo de propuesta también sirve de apoyo y motivación en la búsqueda de conocimiento y desarrollo socioeconómico y sostenible del país.O presente trabalho propor-se a disseminar conhecimentos sobre eficiência energética a estudantes de instituições de ensino no município de João Monlevade no estado de Minas Gerais. Sendo assim, o projeto visou propagar práticas educativas relacionadas ao aproveitamento eficiente da energia elétrica, combatendo o desperdício de energia e promovendo por consequência a conservação de recursos naturais e a diminuição do impacto do custo da energia no orçamento familiar dos participantes e das escolas. Assim, o projeto foi desenvolvido com aproximadamente 144 crianças, de primeiro ao quinto ano do ensino fundamental, que foram abordadas por meio de brincadeiras lúdicas. Durante esse processo, um pré-diagnóstico energético foi realizado em uma das escolas parceiras, com o intuito de apresentar os principais erros em relação à utilização de energia e sugerir ações efetivas e simples para minimiza-los. Além disso, mediante  pesquisa realizada no início e no final do projeto com os participantes, foi possível constatar que a promoção das atividades correspondeu satisfatoriamente aos objetivos do projeto, uma vez que antes da execução apenas 6% dos alunos tinham conhecimento do tema, aumentando para 86% após a promoção. Desta forma, conclui-se que, que o desenvolvimento de projetos deste tipo contribui na formação de agentes promotores do combate ao desperdício de energia elétrica. Tudo isso, através de ações simples que promovem a conservação da energia elétrica sem a diminuição da qualidade de vida. Destaca-se também que esse tipo de proposta também serve de apoio e motivação na busca de conhecimento e desenvolvimento socioeconômico e sustentável do país

High throughput screening of hydrolytic enzymes from termites using a natural substrate derived from sugarcane bagasse

<p>Abstract</p> <p>Background</p> <p>The description of new hydrolytic enzymes is an important step in the development of techniques which use lignocellulosic materials as a starting point for fuel production. Sugarcane bagasse, which is subjected to pre-treatment, hydrolysis and fermentation for the production of ethanol in several test refineries, is the most promising source of raw material for the production of second generation renewable fuels in Brazil. One problem when screening hydrolytic activities is that the activity against commercial substrates, such as carboxymethylcellulose, does not always correspond to the activity against the natural lignocellulosic material. Besides that, the macroscopic characteristics of the raw material, such as insolubility and heterogeneity, hinder its use for high throughput screenings.</p> <p>Results</p> <p>In this paper, we present the preparation of a colloidal suspension of particles obtained from sugarcane bagasse, with minimal chemical change in the lignocellulosic material, and demonstrate its use for high throughput assays of hydrolases using Brazilian termites as the screened organisms.</p> <p>Conclusions</p> <p>Important differences between the use of the natural substrate and commercial cellulase substrates, such as carboxymethylcellulose or crystalline cellulose, were observed. This suggests that wood feeding termites, in contrast to litter feeding termites, might not be the best source for enzymes that degrade sugarcane biomass.</p

Gut Bacterial Communities in the Giant Land Snail Achatina fulica and Their Modification by Sugarcane-Based Diet

The invasive land snail Achatina fulica is one of the most damaging agricultural pests worldwide representing a potentially serious threat to natural ecosystems and human health. This species is known to carry parasites and harbors a dense and metabolically active microbial community; however, little is known about its diversity and composition. Here, we assessed for the first time the complexity of bacterial communities occurring in the digestive tracts of field-collected snails (FC) by using culture-independent molecular analysis. Crop and intestinal bacteria in FC were then compared to those from groups of snails that were reared in the laboratory (RL) on a sugarcane-based diet. Most of the sequences recovered were novel and related to those reported for herbivorous gut. Changes in the relative abundance of Bacteroidetes and Firmicutes were observed when the snails were fed a high-sugar diet, suggesting that the snail gut microbiota can influence the energy balance equation. Furthermore, this study represents a first step in gaining a better understanding of land snail gut microbiota and shows that this is a complex holobiont system containing diverse, abundant and active microbial communities

Cultivation-Independent Methods Reveal Differences among Bacterial Gut Microbiota in Triatomine Vectors of Chagas Disease

Chagas disease is one of the most important endemic diseases of South and Central America. Its causative agent is the protozoan Trypanosoma cruzi, which is transmitted to humans by blood-feeding insects known as triatomine bugs. These vectors mainly belong to Rhodnius, Triatoma and Panstrongylus genera of Reduviidae. The bacterial communities in the guts of these vectors may have important effects on the biology of T. cruzi. For this reason, we analyzed the bacterial diversity hosted in the gut of different species of triatomines using cultivation-independent methods. Among Rhodnius sp., we observed similar bacterial communities from specimens obtained from insectaries or sylvatic conditions. Endosymbionts of the Arsenophonus genus were preferentially associated with insects of the Panstrongylus and Triatoma genera, whereas the bacterial genus Serratia and Candidatus Rohrkolberia were typical of Rhodnius and Dipetalogaster, respectively. The diversity of the microbiota tended to be the largest in the Triatoma genus, with species of both Arsenophonus and Serratia being detected in T. infestans

Capsules from Pathogenic and Non-Pathogenic Cryptococcus spp. Manifest Significant Differences in Structure and Ability to Protect against Phagocytic Cells

Capsule production is common among bacterial species, but relatively rare in eukaryotic microorganisms. Members of the fungal Cryptococcus genus are known to produce capsules, which are major determinants of virulence in the highly pathogenic species Cryptococcus neoformans and Cryptococcus gattii. Although the lack of virulence of many species of the Cryptococcus genus can be explained solely by the lack of mammalian thermotolerance, it is uncertain whether the capsules from these organisms are comparable to those of the pathogenic cryptococci. In this study, we compared the characteristic of the capsule from the non-pathogenic environmental yeast Cryptococcus liquefaciens with that of C. neoformans. Microscopic observations revealed that C. liquefaciens has a capsule visible in India ink preparations that was also efficiently labeled by three antibodies generated to specific C. neoformans capsular antigens. Capsular polysaccharides of C. liquefaciens were incorporated onto the cell surface of acapsular C. neoformans mutant cells. Polysaccharide composition determinations in combination with confocal microscopy revealed that C. liquefaciens capsule consisted of mannose, xylose, glucose, glucuronic acid, galactose and N-acetylglucosamine. Physical chemical analysis of the C. liquefaciens polysaccharides in comparison with C. neoformans samples revealed significant differences in viscosity, elastic properties and macromolecular structure parameters of polysaccharide solutions such as rigidity, effective diameter, zeta potential and molecular mass, which nevertheless appeared to be characteristics of linear polysaccharides that also comprise capsular polysaccharide of C. neoformans. The environmental yeast, however, showed enhanced susceptibility to the antimicrobial activity of the environmental phagocytes, suggesting that the C. liquefaciens capsular components are insufficient in protecting yeast cells against killing by amoeba. These results suggest that capsular structures in pathogenic Cryptococcus species and environmental species share similar features, but also manifest significant difference that could influence their potential to virulence

2 nd Brazilian Consensus on Chagas Disease, 2015

Abstract Chagas disease is a neglected chronic condition with a high burden of morbidity and mortality. It has considerable psychological, social, and economic impacts. The disease represents a significant public health issue in Brazil, with different regional patterns. This document presents the evidence that resulted in the Brazilian Consensus on Chagas Disease. The objective was to review and standardize strategies for diagnosis, treatment, prevention, and control of Chagas disease in the country, based on the available scientific evidence. The consensus is based on the articulation and strategic contribution of renowned Brazilian experts with knowledge and experience on various aspects of the disease. It is the result of a close collaboration between the Brazilian Society of Tropical Medicine and the Ministry of Health. It is hoped that this document will strengthen the development of integrated actions against Chagas disease in the country, focusing on epidemiology, management, comprehensive care (including families and communities), communication, information, education, and research