نتایج جستجو برای: amphibians
تعداد نتایج: 7922 فیلتر نتایج به سال:
Amphibian chytridiomycosis is an emerging infectious disease of amphibians thought to be moved between countries by trade in infected amphibians. The causative fungus, Batrachochytrium dendrobatidis, produces aquatic, motile zoospores; infections have been achieved in experiments by exposing amphibians to water containing zoospores. However, the ability of this fungus to survive in the environm...
Chihuahua is Mexico's largest state, and its physiographic complexity affects the distribution of its herpetofauna. We list amphibians and reptiles for the state of Chihuahua, with their conservation status. We also compare this list to those of six adjoining states in the United States and Mexico (New Mexico, Texas, Coahuila, Durango, Sinaloa, and Sonora). A total of 175 species of amphibians ...
Numerous species of amphibians are frequently utilized as animal models in biomedical research. Despite their relatively common occurrence as laboratory animals, the regulatory guidelines that institutional animal care and use committees (IACUCs) must employ provide little in the way of written standards for ectothermic animals. Yet, as vertebrates, laboratory amphibians are covered by the Nati...
The relative sensitivity of amphibians to chemicals in the environment, including plant protection product active substances, is the subject of ongoing scientific debate. The objective of this study was to compare systematically the relative sensitivity of amphibians and fish to chemicals. Acute and chronic toxicity data were obtained from the U.S. Environmental Protection Agency (U.S. EPA) ECO...
The global amphibian crisis has resulted in renewed interest in captive breeding as a conservation tool for amphibians. Although captive breeding and reintroduction are controversial management actions, amphibians possess a number of attributes that make them potentially good models for such programs. We reviewed the extent and effectiveness of captive breeding and reintroduction programs for a...
Amphibians are a very diverse group of vertebrates; however, in general their feeding is opportunistic with food up to gape width being ingested. Amphibians such as frogs and toads only target moving prey and prefer elongated prey such as crickets or insect larvae that move across their field of vision. However, many aquatic amphibians will target food by scent and will consume inert food. The ...
An updated checklist of the amphibians and reptiles of Honduras is provided. The list includes three amphibian species (Ptychohyla euthysanota, Bolitoglossa odonnelli, Oedipina chortiorum) and two reptile species (Laemanctus waltersi [elevated from subspecies status], Epictia phenops) not included in the most recent checklist of the amphibians and reptiles of the country. Also, one amphibian ge...
Chytridiomycosis is a major threat to amphibian conservation. In Argentina, the pathogenic fungus Batrachochytrium dendrobatidis has been recorded in several localities, and recently, it was registered in amphibians inhabiting low-elevation areas of mountain environments in Córdoba and San Luis provinces. In the present study, we searched for B. dendrobatidis in endemic and non-endemic amphibia...
Amphibians have been widely used to study developmental biology due to the fact that embryo development takes place independently of the maternal organism and that observations and experimental approaches are easy. Some amphibians like Xenopus became model organisms in this field. In the first part of this article, the differentiation of the gonads in amphibians and the mechanisms governing thi...
We review and discuss current knowledge about sex determination in amphibians. The astonishing wide variety of mechanisms of genotypic sex determination is presented and discussed in an evolutionary context. We recall the natural occurrence of transitory juvenile hermaphroditism in some species. Our present knowledge of the mechanisms of sex determination in amphibians is compared to that in ma...
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