954 resultados para 270401 Plant Systematics, Taxonomy and Phylogeny


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The malaria treatment recommended by the World Health Organization involves medicines derived from artemisinin, an active compound extracted from the plant Artemisia annua, and some of its derivatives, such as artesunate. Considering the lack of data regarding the genotoxic effects of these compounds in human cells, the objective of this study was to evaluate the cytotoxicity and genotoxicity, and expressions of the CASP3 and SOD1 genes in a cultured human hepatocellular liver carcinoma cell line (HepG2 cells) treated with artemisinin and artesunate. We tested concentrations of 2.5, 5, 7.5, 10, and 20 μg/mL of both substances with a resazurin cytotoxicity assay, and the concentrations used in the genotoxicity experiments (2.5, 5, and 10 μg/mL) and gene expression analysis (5 mg/mL) were determined. The results of the comet assay in cells treated with artemisinin and artesunate showed a significant dosedependent increase (P < 0.001) in the number of cells with DNA damage at all concentrations tested. However, the gene expression analysis revealed no significant change in expression of CASP3 or SOD1. Our data showed that although artemisinin and artesunate exhibited genotoxic effects in cultured HepG2 cells, they did not significantly alter expression of the CASP3 and SOD1 genes at the doses tested. ©FUNPEC-RP.

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In the present article, we review the feather mites of the genus Anisodiscus Gaud & Mouchet, 1957 associated with sunbirds of Madagascar (Passeriformes: Nectariniidae). Anisodiscus goodmani sp. nov. is described from Cinnyris sovimanga (Gmelin, 1788). This species, as far as we know, bears the longest male intromittent organ (aedeagus) in relation to its body size of any described mite. Anisodiscus megalurus (Trouessart, 1899) is redescribed and illustrated for the first time based on type specimens from the Trouessart collection and recently collected material.http://zoobank.org/urn:lsid:zoobank.org:pub:F1E8A6DB-63CD-4A36-99C5-DC54184FAAE7. © 2013 Copyright Taylor & Francis.

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The purpose of this study is to carry on a thermoeconomic analysis at a biodiesel production plant considering the irreversibilities in each step (part I: biodiesel plant under study and functional thermoeconomic diagram [1]), making it possible to calculate the thermoeconomic cost in US$/kWh and US$/l of the biodiesel production, and the main byproduct generated, glycerin, incorporating the credits for the CO2 that is not emitted into the atmosphere (carbon credits). Assuming a sale price for both the biodiesel and the byproduct (glycerin), the annual revenue of the total investment in a plant with a capacity of 8000 t/year of biodiesel operating at 8000 h/year was calculated. The variables that directly or indirectly influence the final thermoeconomic cost include total annual biodiesel production, hours of operation, manufacturing exergy cost, molar ratio in the transesterification reaction, reaction temperature and pressure in the process. Depending on the increase or decrease in sale prices for both biodiesel and glycerin, the payback is going to significantly increase or decrease. It is evident that, in exergy terms, the sale of glycerin is of vital importance in order to reduce the biodiesel price, getting a shorter payback period for the plant under study. © 2013 Elsevier Ltd. All rights reserved.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Ciências Biológicas (Botânica) - IBB

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Derris urucu é uma planta da Amazônia com propriedades inseticida e ictiotóxica. Estudos com esta espécie reportam a presença de flavonóides, principalmente rotenóides, bem como de estilbenos. A partir do extrato etanólico das folhas de Derris urucu (Leguminosae), três novos diidroflavonóides, denominados urucuol A (1), B (2) e C (3) e o diidroflavonol isotirumalina (4), foram isolados e identificados. As estruturas destes compostos foram elucidadas por uma extensiva análise espectroscópica de RMN uni e bidimensional, UV, IV e dados de EM, além de comparação com dados da literatura. Os compostos isolados (1-4) foram avaliados quanto ao seu potencial sequestrador do radical DPPH• e apresentaram baixo poder antioxidante quando comparados ao antioxidante comercial trans-resveratrol.