RESUMO

The present work aimed to characterize and compare the catalytic properties of amylases from Cunninghamella echinulata and Rhizopus microsporus. The highest production of amylase by C. echinulata, 234.94 U g-1 of dry substrate (or 23.49 U mL-1), was obtained using wheat bran as a substrate, with 50-55% initial moisture and kept at 28 °C for 48 h. The highest production of amylases by R. microsporus, 224.85 U g-1 of dry substrate (or 22.48 U mL-1), was obtained cultivating wheat bran with 65% initial moisture at 45 °C for 24 h. The optimal activity of the amylases was observed at pH 5.0 at 60 °C for C. echinulata enzymes and at pH 4.5 at 65 °C for R. microsporus. The amylases produced by C. echinulata were stable at pH 4.0-8.0, while the R. microsporus enzymes were stable at pH 4.0-10.0. The amylases produced by C. echinulata remained stable for 1 h at 50 °C and the R. microsporus amylases maintained catalytic activity for 1 h at 55 °C. The enzymatic extracts of both fungi hydrolyzed starches from different plant sources and showed potential for liquefaction of starch, however the amylolytic complex of C. echinulata exhibited greater saccharifying potential.

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Microbial ß-glucosidases can be used in several industrial processes, including production of biofuels, functional foods, juices, and beverages. In the present work, production of ß-glucosidase by solid state cultivation of the fungus Thermoascus crustaceus in a low-cost cultivation medium (comprising agroindustrial residues) was evaluated. The highest production of ß-glucosidase, about 415.1 U/g substrate (or 41.51 U/mL), was obtained by cultivating the fungus in wheat bran with 70% humidity, during 96 h at 40°C. The enzymatic activity was optimum at pH 4.5 and 65°C. ß-Glucosidase maintained its catalytic activity when incubated at a pH range of 4.0-8.0 and temperature of 30-55°C. The enzyme was strongly inhibited by glucose; even when the substrate and glucose concentrations were equal, the inhibition was not reversed, suggesting a non-competitive inhibition. In the presence of up to 10% ethanol, ß-glucosidase maintained its catalytic activity. In addition to ß-glucosidase, the enzymatic extract showed activity of 36 U/g for endoglucanase, 256.2 U/g for xylanase, and 18.2 U/g for ß-xylosidase. The results allow to conclude that the fungus T. crustaceus has considerable potential for production of ß-glucosidase and xylanase when cultivated in agroindustrial residues, thereby reducing the cost of these biocatalysts.

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Amylases catalyze the hydrolysis of starch, a vegetable polysaccharide abundant in nature. These enzymes can be utilized in the production of syrups, alcohol, detergent, pharmaceutical products, and animal feed formulations. The aim of this study was to optimize the production of amylases by the filamentous fungus Gongronella butleri by solid-state fermentation and to evaluate the catalytic properties of the obtained enzymatic extract. The highest amylase production, 63.25 U g-1 (or 6.32 U mL-1), was obtained by culturing the fungus in wheat bran with 55% of initial moisture, cultivated for 96 h at 25°C. The enzyme presented optimum activity at pH 5.0 and 55°C. The amylase produced was stable in a wide pH range (3.5-9.5) and maintained its catalytic activity for 1 h at 40°C. Furthermore, the enzymatic extract hydrolyzed starches from different vegetable sources, presenting predominant dextrinizing activity for all substrates evaluated. However, the presence of glucose was observed in a higher concentration during hydrolysis of corn starch, indicating the synergistic action of endo- and exoamylases, which enables the application of this enzymatic extract to produce syrups from different starch sources.

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Diflubenzuron (DFB), an insecticide and acaricide insect growth regulator, can be used in agriculture against insect predators and in public health programs, to control insects and vectors, mainly Aedes aegypti larvae. Due to the lack of toxicological assessments of this compound, the objective of the present study was to evaluate the toxicological effects of subacute exposure to the DFB insecticide in adult male rats. Adult male rats were exposed (gavage) to 0, 2, 4, or 8 mg/kg of DFB for 28 days. No clinical signs of toxicity were observed in the DFB-treated animals of the experimental groups. However, there was an increase in serum levels of alanine aminotransferase in the group that received 8 mg/kg/DFB/day and urea at doses of 4 and 8 mg/kg/DFB/day, without altering other biochemical or hematological parameters. The subacute exposure to the lowest dose of DFB caused significant decrease in testis weight, daily sperm production, and in number of sperm in the epididymis in relation to the control group. However, no alterations were observed in the sperm morphology, testicular, epididymis, liver and kidney histology, or testosterone levels. These findings unveiled the hazardous effects of DFB on male reproduction after the subacute exposure and special attention should be addressed to the effects of low doses of this pesticide.

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Trabalho e depressão; como associar tais fenômenos? Se existe uma incidência elevada de casos de depressão na atualidade, ela se manifestará em diferentes graus nos contextos de trabalho, mesmo que autores reiterem a sua centralidade e importância para a construção da subjetividade. Estudos científicos demonstram a depressão como uma das causas mais expressivas de afastamento do trabalho. O artigo apresenta resultados de um estudo que, por meio da análise de documentos, identificou características de trabalhadores afastados por depressão em uma Universidade do Sul do Brasil. Foram analisados 36 casos identificados como de afastados do trabalho com diagnóstico de depressão e relacionados a motivos diversificados, no período de julho a dezembro de 2009. Os resultados confirmam outros estudos, como a predominância de mulheres, representados por 72 por cento dos casos; e, em muitos casos, há ocorrências sucessivas de afastamentos, inicialmente por períodos curtos, e que foram ampliando o tempo de ausência no trabalho.(AU)

Work and depression, how to associate these phenomena? If there is a high incidence of cases of depression today, it will manifest in different degrees in the labor context, even if authors reiterate its centrality and importance to the construction of subjectivity. Scientific studies show depression as one of the most significant causes of absence from work. The paper presents results of a study which has identified characteristics of workers who were away from their work in a University of Southern Brazil due to depression. Thirty six cases were analyzed and identified as people away from work with a diagnosis of depression and related to varied reasons, from July to December 2009. The results confirm other studies such as the predominance of women, represented by 72 percent of cases, and present data from the historical view of illness, the absence from work and other singularities that permeate the history of the people surveyed.(AU)

Assuntos

RESUMO

Trabalho e depressão; como associar tais fenômenos? Se existe uma incidência elevada de casos de depressão na atualidade, ela se manifestará em diferentes graus nos contextos de trabalho, mesmo que autores reiterem a sua centralidade e importância para a construção da subjetividade. Estudos científicos demonstram a depressão como uma das causas mais expressivas de afastamento do trabalho. O artigo apresenta resultados de um estudo que, por meio da análise de documentos, identificou características de trabalhadores afastados por depressão em uma Universidade do Sul do Brasil. Foram analisados 36 casos identificados como de afastados do trabalho com diagnóstico de depressão e relacionados a motivos diversificados, no período de julho a dezembro de 2009. Os resultados confirmam outros estudos, como a predominância de mulheres, representados por 72 por cento dos casos; e, em muitos casos, há ocorrências sucessivas de afastamentos, inicialmente por períodos curtos, e que foram ampliando o tempo de ausência no trabalho.

Work and depression, how to associate these phenomena? If there is a high incidence of cases of depression today, it will manifest in different degrees in the labor context, even if authors reiterate its centrality and importance to the construction of subjectivity. Scientific studies show depression as one of the most significant causes of absence from work. The paper presents results of a study which has identified characteristics of workers who were away from their work in a University of Southern Brazil due to depression. Thirty six cases were analyzed and identified as people away from work with a diagnosis of depression and related to varied reasons, from July to December 2009. The results confirm other studies such as the predominance of women, represented by 72 percent of cases, and present data from the historical view of illness, the absence from work and other singularities that permeate the history of the people surveyed.

Assuntos