897 resultados para mammal, draon, taotie
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Background: Illegal hunting is one of the major threats to vertebrate populations in tropical regions. This unsustainable practice has serious consequences not only for the target populations, but also for the dynamics and structure of tropical ecosystems. Generally, in cases of suspected illegal hunting, the only evidence available is pieces of meat, skin or bone. In these cases, species identification can only be reliably determined using molecular technologies. Here, we reported an investigative study of three cases of suspected wildlife poaching in which molecular biology techniques were employed to identify the hunted species from remains of meat.Findings: By applying cytochrome b (cyt-b) and cytochrome oxidase subunit I (COI) molecular markers, the suspected illegal poaching was confirmed by the identification of three wild species, capybara (Hydrochoerus hydrochaeris), Chaco Chachalaca (Ortalis canicollis) and Pampas deer (Ozotoceros bezoarticus). In Brazil, hunting is a criminal offense, and based on this evidence, the defendants were found guilty and punished with fines; they may still be sentenced to prison for a period of 6 to 12 months.Conclusions: The genetic analysis used in this investigative study was suitable to diagnose the species killed and solve these criminal investigations. Molecular forensic techniques can therefore provide an important tool that enables local law enforcement agencies to apprehend illegal poachers. © 2012 Sanches et al.; licensee BioMed Central Ltd.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The female prostate is a differentiated organ found in several mammal species, including humans and rodents. This gland has been related to important functions on female reproductive biology. Although the factors, which regulate prostate's development and activity are not well known, its functionality has been related to steroid hormones. It is well established that cyclic changes of estradiol and progesterone levels promote histophysiological adaptations of the whole female body. In contrast, only a few is found about those adaptations in female prostate. Thus, this study aimed to evaluate the effect of estradiol and estradiol+testosterone association on gerbil female prostate in order to verify, which hormonal associations are necessary to its homeostasis. For this, adult females had the ovaries surgically removed. After recovering, they received estradiol and estradiol+testosterone doses through 30 days, each 48 h. The prostatic tissue underwent morphological and morphometric-estereological analysis. Hormonal restriction caused great gland involution and decreased secretory activity, aspects that were reverted by exposure to estradiol and estradiol+testosterone. However, these hormones were not able to re-establish the normal prostate histoarchitecture. The immunoreaction of steroid receptors (ER-α, ER-β, and AR) responded differently among the experimental and control groups, and PCNA assay showed a decrease in epithelial cell proliferation within groups that had hormone privation. Therefore, we conclude that estradiol and testosterone are able to influence prostate morphophysiology and the maintenance of gland homeostasis depends on a balance among these and other hormones. © 2013 Wiley Periodicals, Inc.
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The leishmaniasis is a spectral disease caused by the protozoan Leishmania spp., which threatens millions of people worldwide. Current treatments exhibit high toxicity, and there is no vaccine available. The need for new lead compounds with leishmanicidal activity is urgent. Considering that many lead leishmanicidal compounds contain a quinoidal scaffold and the thiazole heterocyclic ring is found in a number of antimicrobial drugs, we proposed a hybridization approach to generate a diverse set of semi-synthetic heterocycles with antileishmanial activity. We found that almost all synthesized compounds demonstrated potent activity against promastigotes of Leishmania (Viannia) braziliensis and reduced the survival index of Leishmania amastigotes in mammalian macrophages. Furthermore, the compounds were not cytotoxic to macrophages at fivefold higher concentrations than the EC50 for promastigotes. All molecules fulfilled Lipinski's Rule of Five, which predicts efficient orally absorption and permeation through biological membranes, the in silico pharmacokinetic profile confirmed these characteristics. The potent and selective activity of semi-synthetic naphthothiazoles against promastigotes and amastigotes reveals that the 2-amino-naphthothiazole ring may represent a scaffold for the design of compounds with leishmanicidal properties and encourage the development of drug formulation and new compounds for further studies in vivo. © 2013 John Wiley & Sons A/S.
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Overhunting has caused severe decline or local extinction in many large-bodied mammals with direct consequences on plant regeneration, yet little is known about indirect impacts of selective defaunation on commensal species. Cascading effects of species extinction across dependent species groups are likely to occur in coprophagous beetles, because these invertebrates rely on mammal dung for food and nesting material. Both mammals and dung beetles provide important ecosystem services and cascading effects are likely to lead to rapid functional losses. In this study, we described changes in dung beetle communities across a gradient of selective defaunation in continuous Brazilian Atlantic rain forest. We compared the dung beetle assemblages in seven sites with different mammalian biomass and composition. The reduction in the mammalian biomass had a major effect on dung beetle communities by (1) increasing dung beetle abundance with decreasing overall mammal, primate and large mammal biomasses, (2) decreasing dung beetle species richness with decreasing overall mammal biomass and (3) decreasing dung beetle size with decreasing large mammal biomass. Moreover, our study demonstrated the importance of the composition of mammal communities in structuring dung beetle communities. This study documented how selective changes in mammalian biomass and composition affect dung beetle species communities, which in turn may have cascading consequences for the ecosystem. Since most of tropical ecosystems are facing dramatic changes in mammalian composition, it is urgent to evaluate the functional losses associated with such co-extinctions. © 2013 Elsevier Ltd.
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Defaunation, originally conceived as the loss of large vertebrates due to hunting or fragmentation, has been widely used in conservation studies yet the term has been arbitrarily used and poorly defined. Here we refine this term by creating a quantitative index that can be used to compare ecological communities over large zoogeographical regions. We propose a defaunation index (. D) as a weighted measure of dissimilarity between the current assemblage of a given location and a reference assemblage that represents a historical and/or unperturbed state. We analyzed the index by means of three case studies that included two empirical assessments of mammal communities in Neotropical rainforests and one hypothetical example, encompassing a variety of criteria to quantify differences in species density and importance. These cases illustrate the broad range of index applicability and show that incorporating functional differences among species, such as those based on body size, conservation status or evolutionary originality can add important information beyond simply species richness. © 2013 Elsevier Ltd.
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One of the most intriguing questions in ecology is how to identify which and how many species will be able to inhabit human-modified landscapes. Large-bodied mammals structure plant communities by trampling, herbivory, seed dispersal and predation, and their local extinction may have pervasive consequences in plant communities due to the breakdown of key interactions. Although much attention has been given to understanding the effects of defaunation on plant communities, information on the potential impacts on plant functional groups (seed dispersal, seed size and seedling leaves defense) inhabiting continuous forests after defaunation is scarce. We conducted mammal surveys (line transects and camera trapping) to determine the defaunation status of a continuous Atlantic forest in Brazil. Then, we evaluated the effects of defaunation on seedling diversity, richness and abundance of functional groups using 15 plot-pairs (each pair with one open and one exclusion plot) monitored over 36. months. We found that the studied area is partially defaunated because it exhibits high abundance of primates, while terrestrial mammals, such as large rodents and ungulates, are rare. We found no significant changes in either seedling richness and diversity or in the seedling composition of plant functional groups in response to mammal exclosure. Seedling mortality and recruitment were similar between plot types. Our findings suggest that at semi-defaunated areas, where arboreal species are still present, terrestrial mammals have low impacts on the plant community reassembly. © 2013 Elsevier Ltd.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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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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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC
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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC
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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC
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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC