501 research outputs found
Isolation and characterization of Faecalibacterium prausnitzii from calves and piglets.
The goal of our study was to isolate and characterize Faecalibacterium prausnitzii from fecal samples of healthy calves and piglets, in order to develop a novel probiotic for livestock animals. We identified 203 isolates of Faecalibacterium sp., which were clustered in 40 genetically distinct groups. One representative isolate from each cluster was selected for further characterization. The concentrations of the short chain fatty acids (SCFA) acetate, butyrate, propionate and isobutyrate in the culture media were measured by gas chromatography. We observed reduction in the concentration of acetate followed by concomitant increase in the concentration of butyrate, suggesting that the isolates were consuming acetate present in the media and producing butyrate. Butyrate production correlated positively with bacterial growth. Since butyrate has many benefits to the colonic epithelial cells, the selection of strains that produce higher amounts of butyrate is extremely important for the development of this potential probiotic. The effect of pH and concentration of bile salts on bacterial growth was also evaluated in order to mimic the conditions encountered by F. prausnitzii in vivo. The optimal pH for growth ranged between 5.5 and 6.7, while most isolates were inhibited by of the lowest concentration of bile salts tested (0.1%). Antimicrobial resistance profile showed that most isolates of Faecalibacterium sp. were resistant against ciprofloxacin and sulfamethoxazole-trimethoprim. More than 50% of the isolates were resistant to tetracycline, amikacin, cefepime and cefoxitin. A total of 19 different combinations of multidrug resistance were observed among the isolates. Our results provide new insights into the cultural and physiological characteristics of Faecalibacterium prausnitzii illustrating large variability in short chain fatty acid production, in vitro growth, sensitivity to bile salts, and antibiotic resistance and suggesting that future probiotic candidates should be carefully studied before elected for in vivo studies
Farmer and scientific knowledge of soil quality: a social ecological soil systems approach.
This article focuses on how farmers identify and evaluate the quality of soils cultivated and how their indicators compare to those used by agricultural scientists. The aim is to bridge the gap between specific farmer knowledge and universal scientific knowledge by adopting an ecosystem framework applied to agriculture through the concept of agro-ecosystems. This approach was applied to farming in mountainous areas of the Brazilian Atlantic Forest, a global environmental hotspot that has been degraded over time. In order to reverse this trend, local actors have to build agro-ecological systems that maintain environmental quality, agronomic sustainability and socio-economic viability. For this to happen, local and scientific knowledge must be bridged and mutually adapted in order to be successful. This study therefore concentrates on processes of inter-communication between farmers and agricultural scientists concerning the role of soil quality in farming and conservation
O Boto-cinza (sotalia Guianensis) no Estuário dos Rios Piraquê-açu e Piraquê-mirim, Sudeste do Brasil: Ocorrência, Uso do Habitat, Padrão Comportamental e Percepção da Comunidade Tradicional Vitória
O boto-cinza (Sotalia guianensis) é um pequeno cetáceo, com distribuição ampla e
endêmica ao Oceano Atlântico tropical e subtropical, sendo facilmente observado
nas regiões costeiras e estuarinas. As informações relacionadas a essa espécie em
águas brasileiras são escassas e pontuais, assim, o objetivo deste estudo é
conhecer a ecologia do boto-cinza no estuário dos rios Piraquê-Açu e Piraquê-Mirim,
Aracruz, ES. No Brasil, a espécie encontra-se em situação de vulnerabilidade quanto
à conservação de suas populações. O monitoramento do estuário para avaliação da
presença do boto-cinza foi realizado por meio de duas metodologias: ponto fixo e
embarcado. O monitoramento por ponto fixo foi realizado semanalmente em dois
pontos de amostragem, com duração de cinco horas diárias por ponto, entre abril de
2016 e maio de 2017. O monitoramento embarcado foi realizado mensalmente em
seis pontos de amostragem, com duração de cinco horas por saída, entre os meses
julho de 2016 e julho de 2017. Os parâmetros ambientais avaliados foram o
potencial hidrogeniônico, a temperatura superficial da água, o oxigênio dissolvido, a
salinidade, a turbidez, a velocidade dos ventos, a precipitação, o nível e o tipo de
marés em todos os pontos do monitoramento por ponto fixo e do monitoramento
embarcado. As entrevistas etnográficas foram realizadas com 30 pescadores
artesanais que atuam no litoral norte do Espírito Santo e com 30 catadores de
caranguejo que atuam na região de Aracruz. A ocorrência do boto cinza foi
verificada no estuário e apresentou uma variação sazonal, com maior presença da
espécie na primavera e verão. A entrada no estuário foi favorecida pela maré
enchente e o uso preferencial do habitat foi para deslocamento e alimentação. Não
foi verificada correlação entre os parâmetros analisados e a ocorrência da espécie
no ambiente estuarino, com exceção da velocidade dos ventos. O conhecimento
ecológico local dos pescadores artesanais e catadores de caranguejo a respeito do
boto-cinza coincidem com o descrito na literatura e com o observado durante o
monitoramento realizado nesta pesquisa e acrescentam importantes informações ao
conhecimento científico sobre a espécie. A visão positiva a respeito do boto-cinza
por parte da comunidade local representa uma importante ferramenta para
propostas de gestão e conservação da espécie na região
Método del papel de filtro para la medida de la succión del suelo
The capillary pressure of the soil (i.e., the pressure difference between air and water components in soil voids)
is a key variable in the analysis of the hydro-mechanical behavior of unsaturated soils. Therefore a simple and
economical laboratory method for the measurement of the capillary pressure of the soil (also known as soil
matric suction, the reference being the atmospheric pressure), even if a degree of approximation is involved,
is of considerable value. The filter paper method calculates soil suction indirectly by measuring the gravimetric
water content of the filter paper at equilibrium that is related to soil suction through a predetermined calibration
curve. The advantages of the method are simplicity, economy and reasonable accuracy. It can be used
to measure suctions from 10 to 30000 kPa. In this paper, the authors use the contact filter paper method for
matric suction measurements of an unsaturated compacted silty sand (formed by the weathering of granite)
which has been used as a building material for a road in the north of Portugal. The matric suctions inferred
from filter paper measurements depend on the calibration between the water content of the filter paper and
suction. Therefore, three calibration curves proposed at the literature (Chandler et al. 1992; ASTM D 5298;
and Oliveira & Marinho 2006) for the Whatman 42 filter paper are used to interpret the measured filter paper
gravimetric water contents. The results of these tests are compared to other techniques (i.e., tensiometers, and
the osmotic technique) used to measure or control the negative pore water pressure in the compacted soil
specimens and the results obtained are reasonably accurate.La presión capilar del suelo (es decir, la diferencia de la presión entre el aire y los componentes del agua en
vacíos del suelo) es una variable llave en el análisis del comportamiento hidromecánico de suelos no saturados.
Un método por lo tanto simple y económico del laboratorio para la medida de la presión capilar del suelo
(también conocido como la succión matrica del suelo, la referencia que es la presión atmosférica), mesmo si
un grado de aproximación está implicado, es de valor considerable. El método del papel de filtro calcula la
succión indirectamente utilizando curvas de calibración. Las ventajas del método son simplicidad, economía y
exactitud razonable. El método del papel de filtro se puede utilizar para medir succiones a partir del 10 al
30000 kPa. En este artículo, los autores utilizan el método del papel de filtro para la medida de la succión matric
de una arena limosa compactada no saturada (formada por la meteorización del granito) que se ha utilizado
como material de construcción para un camino en el norte de Portugal. Las succiones matric deducidas de
medidas del papel de filtro dependen de una calibración entre el humedade del papel de filtro y la succión. Por
lo tanto, tres curvas de calibración propuestas en la literatura (Chandler et al. 1992; ASTM D 5298; y Oliveira
& Marinho 2006) para el papel de filtro de Whatman 42 se utilizan para interpretar lãs humedades gravimétricas
medidas del papel de filtro. Los resultados de los ensayos se comparan a otras técnicas (es decir, tensiómetros,
y la técnica osmótica) usadas para medir o controlar la presión negativa en lãs muestras compactadas
del suelo y los resultados obtenidos sea razonablemente exacto
Efeito da calibração do papel filtro na curva de retenção de um solo arenoso siltoso compactado
The soil suction is a key variable in the analysis of the hydro-mechanical behavior of unsaturated soils. The filter paper method (FPM) calculates soil suction indirectly by measuring the gravimetric water content of the filter paper at equilibrium that is related to soil suction through a predetermined calibration curve. The matric suctions inferred from FPM depend on the calibration between the water content of the filter paper and suction. Therefore, some published calibration curves (Fawcett and Collis-George 1967; Hamblin 1981; Chandler and Gutierrez 1986; Chandler et al. 1992; ASTM D-5298 1992; and Oliveira and Marinho 2006) for the Whatman 42 filter paper are used to interpret the suction measurements of an unsaturated compacted silty sand. Experimental errors induced by using an inadequate calibration curve are discussed. The test results compared to other techniques used to measure or control suctions in the compacted soil specimens are reasonably accurate.A sucção de um solo é uma variável essencial na análise do comportamento de solos não saturados, e é necessário e importante o desenvolvimento de técnicas, diretas e indiretas, de determinação da pressão capilar de solos, que tentam aliar à simplicidade de aplicação, o que se espera ser uma precisão aceitável para os problemas reais do dia a dia da engenharia de solos. O MPF determina a sucção de forma indireta e depende da precisão em que foi determinada a curva de calibração. Várias curvas de calibração para o papel filtro Whatman 42 têm sido propostas na literatura (Fawcett and Collis-George 1967; Hamblin 1981; Chandler and Gutierrez 1986; Chandler et al. 1992; ASTM D-5298 1992; e Oliveira and Marinho 2006). Este artigo discute o uso do MPF para determinar valores de sucção de um solo arenoso siltoso compactado não saturado. Comparam-se os resultados obtidos com outras técnicas utilizadas para medir ou controlar sucções de amostras compactadas do solo arenoso siltoso e conclui-se que o MPF com adequada curva de calibração pode apresentar resultados satisfatórios.Universidade de Coimbra. Faculdade de Ciências e Tecnologia (FCT-UC)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
CYP712K4 catalyzes the C-29 oxidation of friedelin in the Maytenus ilicifolia quinone methide triterpenoid biosynthesis pathway
The native Brazilian plant Maytenus ilicifolia accumulates a set of quinone methide triterpenoids with important pharmacological properties, of which maytenin, pristimerin and celastrol accumulate exclusively in the root bark of this medicinal plant. The first committed step in the quinone methide triterpenoid biosynthesis is the cyclization of 2,3-oxidosqualene to friedelin, catalyzed by the oxidosqualene cyclase friedelin synthase (FRS). In this study, we produced heterologous friedelin by the expression of M. ilicifolia FRS in Nicotiana benthamiana leaves and in a Saccharomyces cerevisiae strain engineered using CRISPR/Cas9. Furthermore, friedelin-producing N. benthamiana leaves and S. cerevisiae cells were used for the characterization of CYP712K4, a cytochrome P450 from M. ilicifolia that catalyzes the oxidation of friedelin at the C-29 position, leading to maytenoic acid, an intermediate of the quinone methide triterpenoid biosynthesis pathway. Maytenoic acid produced in N. benthamiana leaves was purified and its structure was confirmed using high-resolution mass spectrometry and nuclear magnetic resonance analysis. The three-step oxidation of friedelin to maytenoic acid by CYP712K4 can be considered as the second step of the quinone methide triterpenoid biosynthesis pathway, and may form the basis for further discovery of the pathway and heterologous production of friedelanes and ultimately quinone methide triterpenoids
Impact of gender on the decision to participate in a clinical trial: a cross-sectional study
Background
In order for Informed Consent to be ethical and valid each clinical trial participant must be able to make a voluntary decision to participate, free from pressure or coercion. Nonetheless, many factors may influence the decision reached, and such influences may be different for male and female volunteers. Being aware of these differences may help researches develop better processes for obtaining consent that safeguard the right of autonomy for all participants. The goal of this study was to evaluate potential gender-based differences in the factors influencing clinical trial participation. Methods
This cross-sectional study was conducted in the Northeast region of Minas Gerais, Brazil, in October 2011. A structured questionnaire was administered to 143 volunteers (48 male, 95 female) screened for participation in a clinical study of an investigational functional food with potential anthelminthic properties. Answers regarding their decision to participate in the study were compared, by gender, using chi-square and Mann Whitney tests. Odds ratios (OR) was used to measure association. Results
A majority of subjects (58% of males, 59% of females) listed the desire to collaborate with the development of a product against parasitic worms as their main reason for participation. Females were significantly more likely to report a decision influenced by friends, family, or researchers (OR 3.14, 3.45, and 3.46 respectively, p \u3c 0.005). Females were also significantly more likely to report a decision influenced by general altruistic considerations (OR 8.45, p \u3c 0.005). There was no difference, by gender, in the report of decisions influenced by informational meetings, understanding of the disease, or the availability of medical treatments or exams. There was also no difference in knowledge of the rights of research participants. Conclusion
Study results indicate that there is a strong difference between male and female participants regarding social influences on the decision to participate in clinical research. Further research into the impact this may have on autonomy is warranted
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