992 resultados para Leaf-litter frogs


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The objective of this study was to evaluate the structure of Tanzania grassland grazed by goats managed with different residue leaf area index (RLAI) under intermittent stocking. The experiment was carried out from February to August, 2008. The treatments consisted of three different targets RLAI (0.8, 1.6 and 2.4) and 95% light interception (LI) criterion determined the rest period. Forage samples were collected at average height sampling points and weighed. Subsequently, a smaller sample was removed to separate the morphological components (leaf, stem and dead material) and to determine the structural and productive features. The canopy architecture was evaluated by the method of inclined point quadrat. The pre-grazing height in the paddocks were significantly different among treatments. RLAI influenced dry matter contents of green forage, leaf, stem and total, with the exception of dry matter of dead material, where the lowest values were observed for 0.8 RLAI. Thus, RLAI modifies canopy structure and is sensitive to canopy height changes throughout the year. Pasture regrowth is not compromised by residual leaf area indexes between 0.8 and 2.4, when climatic factors are not limiting.

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The ecological restoration is an alternative to increasingly important for biodiversity conservation. However, actions need indicators to evaluate its effectiveness in restablishment ecological processes, including nutrient cycling. The objective of this study was to compare the annual litterfall from five different treatments for forest restoration, compared with a neighboring fragment of Seasonal Semideciduous Forest, in order to subsidize their management plans for ecological restoration. Litter traps of 0.25m² were used, and a total production was: 1700.6 Kg. ha-1.year-1(treatment 1), 7748.1 Kg. ha-1.year-1(treatment 2), 7120.8 Kg. ha-1.year-1 (treatment 3), 9254.5 Kg. ha- 1.year-1 (treatment 4), 7130.2 Kg. ha-1.year-1 (treatment 5) and 8876 Kg. ha-1.year-1 (fragment of Seasonal Semideciduous Forest - treatment 6). The leaf fraction was the largest contributor to the deposition of litter in all treatments. Litter served as a good environmental indicator that can be used as a tool to support management plans. Key words: Litterfall, forest restoration and Seasonal Semideciduous Forest

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The aims of this study are to determine how anuran calling males are spatially and temporally distributed in the Morro do Diabo State Park (MDSP), and to test for indicator species in different breeding habitats. We found high species turnover among breeding habitats of different hydroperiods. Our results indicate that spatial partitioning is more important than seasonal occurrence in permitting species coexistence at MDSP. Indicator Species Analysis identified one species associated with a local stream, one species associated with permanent ponds, two species associated with temporary ponds, and three species associated with a semipermanent pond. Guilds of species do not appear to stratify their distributions throughout the year, since most species occur during the rainy and warm months and are thus temporally overlapping. The main conservation implication of our work is the need to protect the different areas of the park where these unique breeding habitats, and their associated anuran assemblages, are found.

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Purpose: The antitumor activity of Kielmeyera coriacea (Clusiaceae), a medicinal plant used in the treatment of parasitic, as well as fungal and bacterial infections by the Brazilian Cerrado population, was investigated. Methods: A chloroform extract (CE) of K. coriacea was tested in the murine melanoma cell line (B16F10-Nex2) and a panel of human tumor cell lines. Tumor cell migration was determined by the wound-healing assay and the in vivo antitumor activity of CE was investigated in a melanoma cell metastatic model. 1H NMR and GC/MS were used to determine CE chemical composition. Results: We found that CE exhibited strong cytotoxic activity against murine melanoma cells and a panel of human tumor cell lines in vitro. CE also inhibited growth of B16F10- Nex2 cells at sub lethal concentrations, inducing cell cycle arrest at S phase, and inhibition of tumor cell migration. Most importantly, administration of CE significantly reduced the number of melanoma metastatic nodules in vivo. Chemical analysis of CE indicated the presence of the long chain fatty compounds, 1-eicosanol, 1-docosanol, and 2-nonadecanone as main constituents. Conclusion: These results indicate that K. coriacea is a promising medicinal plant in cancer therapy exhibiting antitumor activity both in vitro and in vivo against different tumor cell lines.

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

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The allelopathic potential of leaf extracts from the medicinal plant Myrcia guianensis (Aubl.) DC. was studied in Petri dish bioassays on sorghum and determined the seed germination, germination rate index (GRI), root growth, secondary root number, the genes involved in root development (SHR, PHB, PHV and REV) and microRNA 166 that regulates these genes. The hydroalcoholic extract was more inhibitory than methanol extract (moderate inhibition) and aqueous extract at 25 and 100% concentration were least inhibitory. Application of higher dose of hydroalcoholic M. guianenesis leaf extracts on sorghum seeds, inhibited the root development and changed the expression of SHR and PHB genes and microRNA 166. This suggested that the expression of these genes could be indicator of allelopathic potential for inhibition of root development in sorghum.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq)

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

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)