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Toad
About: Toad is a research topic. Over the lifetime, 1624 publications have been published within this topic receiving 28732 citations.
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TL;DR: It was found that blood was always hypertonic to the external solution, but at the highest salinity tolerated (i.e. 300 mOsM) the osmotic gradient across the skin was nearly abolished, and Neurohypophyseal hormone increased water uptake and sodium transport to levels similar to those in tap water frogs.
Abstract: The physiological adaptation of the frog Rana ridibunda to saline environment was studied. It was found that blood was always hypertonic to the external solution, but at the highest salinity tolerated (i.e. 300 mOsM) the osmotic gradient across the skin was nearly abolished. Water uptake by the living frog remained unchanged, whereas sodium transport across the skin decreased markedly. Neurohypophyseal hormone increased water uptake and sodium transport to levels similar to those in tap water frogs. Water content of the tissues was not affected by saline adaptation, although it varied appreciably under acute conditions. Oxygen consumption increased in dehydrated frogs, but not in adapted ones. The results are discussed and compared to the euryhaline toad Bufo viridis; the importance of high urea levels for high salt adaptation is stressed.
13 citations
TL;DR: It is concluded that, up to stage 22, no significant changes in the expression of glutathione transferases isoenzymes occurred during Bufo bufo embryo development.
13 citations
12 citations
TL;DR: Data are consistent with the previously suggested action of staphylococcal alpha toxin on cell membranes and suggest that energy-dependent transport processes are inhibited and the stimulation of oxygen consumption may be due to an additional effect on oxidative phosphorylation.
Abstract: Purified staphylococcal alpha toxin was found to inhibit the active transport of sodium across the isolated toad bladder when applied to the serosal but not to mucosal surface. Heating or the addition of specific antitoxin abolished this effect. Low temperatures reduced this activity significantly. Application of vasopressin to the bladder serosa shortly after toxin resulted in only weak and transient stimulation of sodium transport; once maximal toxin activity had been established, exposure to the hormone was without effect. Transport in bladders previously stimulated by vasopressin was rapidly inhibited by alpha toxin. Concentrations that suppressed active sodium transport completely within 30-45 min produced a significant increase in oxygen consumption by minced bladder tissue within the same period; antitoxin neutralized this activity. 2,4-dinitrophenol also inhibited sodium transport and stimulated oxygen consumption by the toad bladder. The addition of 2,4 dinitrophenol to bladder tissue in which respiration was maximally stimulated by alpha toxin resulted in a further increase in respiratory rate. The addition of toxin to bladder tissue after its exposure to a concentration of 2,4 dinitrophenol known to uncouple oxidative phosphorylation produced a significant stabilization but no increment in respiratory rate. The data are consistent with the previously suggested action of staphylococcal alpha toxin on cell membranes and suggest that energy-dependent transport processes are inhibited. The stimulation of oxygen consumption may be due to an additional effect on oxidative phosphorylation.
12 citations