Amphibian Declines
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Habitat-split and the global decline of amphibians / Desconexão de habitats e o declinio global dos anfibios
O nicho dos anfíbios muda drasticamente ao longo da ontogenia, forçando larvas e pós-metamórficos a ocuparem dois hábitats distintos. Em áreas desmatadas, sítios reprodutivos aquáticos e fragmentos florestais podem ser muito desconectados, isolando o hábitat dos girinos do hábitat dos adultos, em um padrão de fragmentação que chamamos de descone
Publicado em: 2007
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2. Activities of Temporin Family Peptides against the Chytrid Fungus (Batrachochytrium dendrobatidis) Associated with Global Amphibian Declines
Temporin A and structurally related peptides produced in amphibian dermal granular glands and in wasp venom were tested for growth inhibition of Batrachochytrium dendrobatidis, a pathogen associated with global amphibian declines. Two natural amphibian temporins, a wasp temporin, and six synthetic analogs effectively inhibited growth. Differences in potency
American Society for Microbiology.
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3. Synergism between UV-B radiation and a pathogen magnifies amphibian embryo mortality in nature.
Previous research has shown that amphibians have differential sensitivity to ultraviolet-B (UV-B) radiation. In some species, ambient levels of UV-B radiation cause embryonic mortality in nature. The detrimental effects of UV-B alone or with other agents may ultimately affect amphibians at the population level. Here, we experimentally demonstrate a synergist
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4. Chytridiomycosis causes amphibian mortality associated with population declines in the rain forests of Australia and Central America
Epidermal changes caused by a chytridiomycete fungus (Chytridiomycota; Chytridiales) were found in sick and dead adult anurans collected from montane rain forests in Queensland (Australia) and Panama during mass mortality events associated with significant population declines. We also have found this new disease associated with morbidity and mortality in wil
The National Academy of Sciences.
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5. UV repair and resistance to solar UV-B in amphibian eggs: a link to population declines?
The populations of many amphibian species, in widely scattered habitats, appear to be in severe decline; other amphibians show no such declines. There is no known single cause for the declines, but their widespread distribution suggests involvement of global agents--increased UV-B radiation, for example. We addressed the hypothesis that differential sensitiv
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6. Synergism between trematode infection and pesticide exposure: A link to amphibian limb deformities in nature?
The apparently rapid increase in the prevalence of amphibian limb deformities has led to substantial interest from ecologists and public health professionals. Hypotheses proposed to explain the deformities fall into two broad categories: chemical contaminants and trematode infection. Although there are convincing experimental demonstrations that certain fact
The National Academy of Sciences.
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7. Reversing introduced species effects: Experimental removal of introduced fish leads to rapid recovery of a declining frog
Amphibian population declines and extinctions are occurring even in the world's least impacted areas. The introduction and spread of nonnative predators is one of many proposed causes of amphibian declines. Correlational studies have shown a negative relationship between introduced fishes and declining amphibians, but little direct experimental evidence is a
National Academy of Sciences.
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8. Histone RNA in amphibian oocytes visualized by in situ hybridization to methacrylate-embedded tissue sections.
We present an in situ hybridization method for detecting cellular RNAs in tissue sections using methacrylate as the embedding medium. The technique offers the advantage of superior morphological preservation compared with previously published procedures. Since sections can be cut 1 micron or less in thickness, full advantage is taken of the short path length
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9. The Bacterially Produced Metabolite Violacein Is Associated with Survival of Amphibians Infected with a Lethal Fungus ▿
The disease chytridiomycosis, which is caused by the chytrid fungus Batrachochytrium dendrobatidis, is associated with recent declines in amphibian populations. Susceptibility to this disease varies among amphibian populations and species, and resistance appears to be attributable in part to the presence of antifungal microbial species associated with the sk
American Society for Microbiology (ASM).
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10. Hermaphroditic, demasculinized frogs after exposure to the herbicide atrazine at low ecologically relevant doses
Atrazine is the most commonly used herbicide in the U.S. and probably the world. It can be present at several parts per million in agricultural runoff and can reach 40 parts per billion (ppb) in precipitation. We examined the effects of atrazine on sexual development in African clawed frogs (Xenopus laevis). Larvae were exposed to atrazine (0.01–200 ppb) b
National Academy of Sciences.
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11. cDNA cloning and developmental expression of fibroblast growth factor receptors from Xenopus laevis.
The heparin-binding growth factors constitute a family of homologous polypeptides including basic and acidic fibroblast growth factors (FGFs). These factors participate in a variety of processes, including wound healing, angiogenesis, neuronal survival, and inductive events in the early amphibian embryo. We have isolated three closely related species of cDNA