... prefer conspecific to heterospecific calls. Advertisement calls of three relatively recently (∼8.5 Mya) diverged species – Xenopus laevis , X. petersii and X. victorianus – include rapid trains of sound pulses (fast trills). We show that while fast trills are similar in pulse rate (∼60 pulses s −1...

... is energy intensive. Here we examine the effects of nutrient availability on visual system development in Xenopus laevis tadpoles. During the first week of development, tadpoles draw nutrients from maternally provided yolk. Upon yolk depletion, animals forage for food. By altering access to external...

...Shun Maekawa; Hitomi Iemura; Yuko Kuramochi; Nami Nogawa-Kosaka; Hironori Nishikawa; Takehito Okui; Youichi Aizawa; Takashi Kato SUMMARY Diminished erythrocyte count and erythropoiesis have been reported during hypothermia in some ectothermic animals. In this study, the African clawed frog, Xenopus...

...Taffeta M. Elliott; Darcy B. Kelley SUMMARY In murky, crowded ponds in South Africa, female clawed frogs, Xenopus laevis (Daudin), vocalize to signal reproductive state. Female calls consist of acoustically similar clicks delivered in trains with characteristic rates. The rapping call of a sexually...

... of DNA during amphibian metamorphosis. In this study, nuclei were isolated from Xenopus laevis at various developmental stages. The nuclei were examined in both an unfixed state and a fixed state. The nuclei were stained with propidium iodide and analyzed by flow cytometry to determine their fluorescence...

...Thomas D. Lambert; Jenny Howard; Andy Plant; Steve Soffe; Alan Roberts SUMMARY Hatchling Xenopus laevis tadpoles spend most of their time attached to objects or the water surface by mucus secreted by a gland on the head. While attached, swimming activity and responsiveness to swim-initiating...

... amphibian species (Bufo marinus, Ambystoma tigrinum, Rana catesbeiana, Necturus maculosus and Xenopus laevis) . Although urea i /urea e ratios were uniformly close to 1·0, Tamm i /Tamm e ratios correlated directly with the degree of ammoniotelism in each species, ranging from 9·1 (Bufo , 10% ammoniotelic...

...R. G. Boutilier; G. Shelton ABSTRACT A closed, extracorporeal loop, containing oxygen and carbon dioxide electrodes, was developed in order to make continuous measurements of lung gas and in undisturbed Xenopus laevis . Pulmonary R values are about 0 ·8 during periods of lung ventilation in resting...

...Robert G. Boutilier; Graham Shelton ABSTRACT Pre-and post-dive breathing patterns, blood oxygenation and acid-base balance have been examined in voluntarily and forcibly submerged Xenopus laevis . Enforced 30-min dives led to a large acidosis with both respiratory (CO 2 ) and metabolic (lactic acid...

...R. G. Boutilier; G. Shelton ABSTRACT The respiratory properties of blood from voluntarily diving Xenopus seem well matched to the animal’s habit of ventilating its lungs in an intermittent fashion. Compared with more terrestrial anurans, the high oxyhaemoglobin affinity (P 50 = 29·6 Torr, pH 7·73...

... is sustained. After a brief review, which suggests that positive feedback excitation could be involved, evidence from Xenopus embryos is considered. Here a brief skin stimulus can evoke long episodes of swimming even in curarized embryos. Feedback excitation provides a possible explanation for sustaining...

...Peter Görner; Peter Moller; Wolfgang Weber ABSTRACT Intact Xenopus sp. responded to a train of surface waves with a single, stimulus-directed motor response which consisted of a turning component and a displacement component. The turning angle increased in a linear fashion with the stimulus angle...