916 resultados para Vertebrates


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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Red blood cells (RBCs) from most vertebrates restore volume upon hypertonic shrinkage and the mechanisms underlying this regulatory volume increase (RVI) have been studied extensively in these cells. Despite the phylogenetically interesting position of reptiles, very little is known about their red cell function. The present study demonstrates that oxygenated RBCs in all major groups of reptiles exhibit no or a very reduced RVI upon -25% calculated hyperosmotic shrinkage. Thus, RBCs from the snakes Crotalus durissus and Python regius, the turtle Trachemys scripta and the alligator Alligator mississippiensis showed no statistically significant RVI within 120 min after shrinkage, while the lizard Tupinambis merianae showed 22% volume recovery after 120 min. Amiloride (10(-4) M) and bumetanide (10(-5) M) had no effect on the RVI in T merianae, indicating no involvement of the Na(+)/H(+) exchanger (NHE) or the Na(+)/K(+)/2Cl(-) co-transporter (NKCC) or insentive transporters. Deoxygenation of RBCs from A. mississippiensis and T merianae did not significantly affect RVI upon shrinkage. Deoxygenation per se of red blood cells from T merianae elicited a slow volume increase, but the mechanism was not characterized. It seems, therefore, that the RVI response based on NHE activation was lost among the early sauropsids that gave rise to modern reptiles and birds, while it was retained in mammals. An RVI response has then reappeared in birds, but based on activation of the NKCC. Alternatively, the absence of the RVI response may represent the most ancient condition, and could have evolved several times within vertebrates. (C) 2008 Elsevier B.V. All rights reserved.

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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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The predation on vertebrates by birds, including bats, is very common in some families (Accipitridae, Falconidae, Tytonidae, Strigidae), constituting their main diet. For other families (except those that feed strictly on fish), it is occasional and sometimes a matter of opportunity. Here we recorded the predation on a bat (Platyrrhinus lineatus) by the neotropical bird plush-crested jay (Cyanocorax chrysops). on July 26, 2009, around 11:00 am, we recorded an individual of C. chrysops taking part of a P. lineatus on its beak. This record occurred on Jacarezinho Farm (Valparaiso [long dash] SP). The prey species identification was done by visual observation, considering the bat size and its external morphology, especially by the presence of the white dorsal bright stripe. Probably, Platyrrhinus lineatus behavior, which involves living together or in couples on tree canopies, made the capture by the plush-crested jay easier. This is a new record for the diet of C. chrysops and highlights the necessity of additional studies related to birds diet in the Neotropics, even the more conspicuous ones.

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

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Bats are predated for some of vertebrates and invertebrates. Some opportunistic species preys these animals' prisoners in nests during procedures of capture in field. This study records the predation of Carollia perspicillata (Linnaeus, 1758) and Sturnira lilium (E. Geoffroy, 1810) for Chironectes minimus (Zimmermann, 1780) on riparian forest of the brook Talhadinho belonging of the São Paulo, São Paulo, Southeast Brazil, and also presents a lifting previous of mammalian what they present the same one behavior opportunistic predatory, discussing measures simple to avoid this type of predation.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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A dieta de uma população de jaguarundi (Puma yagouaroundi) (Geoffroy, 1803) (Carnivora, Felidae) foi estudada entre novembro de 2000 e novembro de 2001, em 24,9 km² de mosaico de Mata Atlântica secundária e reflorestamento de eucalipto na Serra de Paranapiacaba, São Paulo, Brasil. A análise das 26 amostras fecais e regurgitadas, obtidas em 570.1 km de percurso, indicou o consumo de 19 itens alimentares em um total de 74 ocorrências de presas. Pequenos mamíferos foram os itens mais frequentemente encontrados na dieta (42,5%), seguidos por aves (21%), répteis (14%) e mamíferos de tamanho médio (3%). A porcentagem de ocorrência (PO) sugere que a dieta concentra-se, principalmente, em pequenos roedores (30%) e aves (21%). Foi também registrada a predação sobre serpentes da família Viperidae. A amplitude de nicho alimentar padronizada (Bsta = 0,76) mostra uma dieta generalista, entretanto, os dados sugerem que o jaguarundi consome principalmente pequenos vertebrados (mamíferos, aves ou répteis), sobretudo, espécies terrestres.