5 research outputs found
MODELAGEM E SIMULAÇÃO DA DIFUSÃO MULTICOMPONENTE DURANTE A DESIDRATAÇÃO OSMÓTICA EM PEDAÇOS DE MELÃO
A perda de água e o ganho de açúcar foram
modelados durante o processo de desidratação osmótica de
pedaços de melão. A transferência de soluto para a fruta e
de água para a solução, foi modelada com base na 2ª Lei generalizada
de Fick para difusão simultânea e resolvida por
meio do método de elementos fi nitos utilizando o software
COMSOL Multiphysics 3.2. Os coefi cientes de difusão
principais e cruzados, a relação entre o coefi ciente de transferência
de massa e o de condutividade mássica, bem como
o número de Biot foram determinados na simulação com
a aplicação do método de otimização simplex por meio da
minimização dos desvios percentuais. O valor dos desvios
entre os dados experimentais e simulados foi de 4,71% para
a sacarose e 4,51% para a água e a simulação indicou que
a resistência externa pode ser desprezada no fenômeno de
transferência de massa estudado. O resultado da simulação
apresentou bom ajuste dos coefi cientes de difusão aos valores
experimentais validando a capacidade preditiva do
modelo empregado. O sistema desenvolvido para simular a
difusão da água e do soluto permitirá o controle e a modulação
do conteúdo de açúcar nos pedaços de melão
Brazilian Propolis Antileishmanial and Immunomodulatory Effects
The antileishmanial and immunomodulatory effects of propolis collected in Botucatu, São Paulo State, Brazil, were evaluated in Leishmania (Viannia) braziliensis experimental infection. The antileishmanial effect of propolis on promastigote forms was verified by reducing growth and by promoting morphologic alterations observed by scanning electron microscopy. In in vitro immunomodulatory assays, macrophages were pretreated with propolis and then infected with L. (V.) braziliensis. In vivo, supernatants from liver cells and peritoneal exudate of BALB/c mice pretreated with propolis and infected with Leishmania (107/mL promastigotes) were collected, and TNF-α and IL-12 were measured by ELISA. Macrophages incubated with propolis showed a significant increase in interiorization and further killing of parasites. An increased TNF-α production was seen in mice pretreated with propolis, whereas IL-12 was downregulated during the infection. In conclusion, Brazilian propolis showed a direct action on the parasite and displayed immunomodulatory effects on murine macrophages, even though the parasite has been reported to affect the activation pathways of the cell. The observed effects could be associated with the presence of phenolic compounds (flavonoids, aromatic acids, and benzopyranes), di- and triterpenes, and essential oils found in our propolis sample
Brazilian propolis antileishmanial and immunomodulatory effects
The antileishmanial and immunomodulatory effects of propolis collected in Botucatu, São Paulo State, Brazil, were evaluated in Leishmania (Viannia) braziliensis experimental infection. The antileishmanial effect of propolis on promastigote forms was verified by reducing growth and by promoting morphologic alterations observed by scanning electron microscopy. In in vitro immunomodulatory assays, macrophages were pretreated with propolis and then infected with L. (V.) braziliensis. In vivo, supernatants from liver cells and peritoneal exudate of BALB/c mice pretreated with propolis and infected with Leishmania (107/mL promastigotes) were collected, and TNF- α and IL-12 were measured by ELISA. Macrophages incubated with propolis showed a significant increase in interiorization and further killing of parasites. An increased TNF- α production was seen in mice pretreated with propolis, whereas IL-12 was downregulated during the infection. In conclusion, Brazilian propolis showed a direct action on the parasite and displayed immunomodulatory effects on murine macrophages, even though the parasite has been reported to affect the activation pathways of the cell. The observed effects could be associated with the presence of phenolic compounds (flavonoids, aromatic acids, and benzopyranes), di- and triterpenes, and essential oils found in our propolis sample. © 2013 Suelen Santos da Silva et al
Bioactive organocopper compound from Pseudomonas aeruginosa inhibits the growth of Xanthomonas citri subsp. citri
Citrus canker is a lot destructive disease of citrus species. The challenge is to find new compounds that show strong antibiotic activity, low toxicity to plants and the environment. The objectives of the present study are (1) produce, purify and evaluate the antibiotic activity of secondary metabolites produced by induction by P. aeruginosa LV strain in vitro against Xanthomonas citri subsp. citri (strain 306), (2) study the potential for semi-purified secondary metabolites on foliar application to control citrus canker under greenhouse conditions, (3) identify the antibiotic activity in orange leaf mesophyll infected with strain 306 by electron microscopy. Two pure bioactive compounds were isolated, organocopper antibiotic compound and phenazine-1-carboxamide. The phenazine-1-carboxamide did not show any antibiotic activity under the experimental conditions used in this study. The organocopper antibiotic compound showed a high level of antibiotic activity with a minimum inhibitory concentration of 0.12 µg mL-1. In greenhouse tests for control of citrus canker in orange trees, the semi-purified fraction F3d, reduced lesion formation about 97%. The concentration used was five hundred times lower than recommended commercial product of metallic copper-based. Electron microscopy showed that F3d altered the exopolysaccharide matrix and causing cell lysis of the pathogen inside the citrus canker lesions. These results suggest that secondary metabolites produced by induction by P. aeruginosa LV strain has a high potential to be used as a bioproduct to control citrus canker