Under certain conditions, nitrite can be present in freshwater systems in quantities that are toxic to the fauna. I exposed wood frog (Rana sylvatica) and eastern tiger salamander (Ambystoma tigrinum tigrinum) embryos and young tadpoles and larvae to elevated concentrations of nitrite in chronic toxicity tests: 0, 0.3, 0.6, 1.2, 2.1, 4.6, and 6.1 mg/L NO2-N, exposing individuals as both embryos...

Centrophenoxine exhibited some interesting actions at the neuromuscular junction. The drug was ineffective in rat or chick preparations, but blocked neuromuscular transmission in frog preparations. The blockade was reversed by adrenaline, potassium, choline and physostigmine. The drug had no effect on muscle contractility or endplate cholinoceptor. Hemicholinium 3 induced a neuromuscular blocka...

restructuring the recent developments in the power system and problems arising from construction as well as the maintenance of large power plants lead to increase in using the distributed generation (dg) resources. dg units due to its specifications, technology and location network connectivity can improve system and load point reliability indices. in this paper, the allocation and sizing of di...

the aim of this study was to find any structural differences between the digital pads of forelimbs and hind limbs as well as more careful investigation of the internal and external structures of the toe-pad. in this study, pad morphology and cytology in litoria caerulea is described using sem, tem and light microscopy. at the gross anatomical level, toe-pads in hind limbs were subdivided into m...

Rabbit antibodies were prepared against the major hemoglobin components of the larval and adult stages of R. catesbeiana . The properties of the antisera were studied by double immunodiffusion, precipitation, and complement fixation . The antisera to tadpole and frog hemoglobins did not cross-react with either hemoglobin or apohemoglobin . The antiserum against frog hemoglobin was used for the ...

Rabbits were immunized with frog or tadpole haemoglobin purified either by chromatography or by polyacrylamide gel electrophoresis. The obtained rabbit antisera were shown to be specific for frog or tadpole haemolysates by double diffusion, immunoprecipitation and immunonuorescence. Indirect immunofluorescent staining of peripheral blood smears of Rana catesbeiana tadpoles at the metamorphic cl...

Comparisons of climate data from the two known habitats of Leiopelma hamiltoni (a small deforested rock tumble near the summit of Stephens Island called the "frog bank" and a forest remnant on Maud Island) show that the two are remarkably similar, apart from greater extremes of temperature and humidity occurring at the open rock surface of the frog bank than on the surface of the Maud Island ha...

BACKGROUND Frog skin secretions have potentials against a wide spectrum of bacteria. Also, frog skin compositions have healing properties. OBJECTIVES The aim of this study was to investigate the antibacterial potentials along with healing properties of frog skin Rana ridibunda, a species which thoroughly lives in Iran marshes, as a biological dressing on wounds. MATERIALS AND METHODS In thi...

Muscle spindles are critically involved in the reflex regulation of the dynamic and static actions of muscles; the sensitivity of the actions is under strong efferent control2, 8. In the usually studied mammal, the cat, the receptor elements in the muscle spindles convey by two types of fibers (Groups I and II) muscle displacement and velocity information to the central nervous system. The func...

Why are they called túngara frogs? As in most frog species, males call to attract females. Unlike most other frog species, túngara frogs produce both simple and complex calls. A simple call consists of a frequencymodulated sweep called a ‘whine’, while a complex call is a whine plus one to six or seven broadband ‘chucks’. The name ‘túngara’ frog is onomatopoeically derived from the male’s call:...