Toad

About: Toad is a research topic. Over the lifetime, 1624 publications have been published within this topic receiving 28732 citations.

The Amazonian toad Rhaebo guttatus is able to voluntarily squirt poison from the paratoid macroglands

Abstract: Amphibian defence mechanisms commonly rely on cutaneous toxins produced in either isolated or clustered glands, such as toad parotoid macroglands. In contrast to the passive mechanism of poison liberation in other amphibians, we discovered that the Amazonian toad Rhaebo guttatus is unique because it can voluntarily squirt jets of poison from its parotoids. Amphibians commonly use toxic, cutaneous se- cretions produced by glands spread over the body as a defence against predators (Duellman and Trueb, 1994). In bufonids, these glands are grouped behind the eyes, forming a pair of pos- torbital structures, known as parotoid macrog- lands (Toledo and Jared, 1995; Tyler, Burton and Bauer, 2001). Amongst amphibians, toads provide a classic example of passive defence, based on contact between a predator's oral mu- cosa and cutaneous poisonous secretion. When threatened, they react by inflating their bodies in such a way that the parotoids become turgid and primed. When an aggressor bites a toad, it becomes the agent of its own poisoning by trig- gering the macroglands and, consequently, re- ceiving jets of poison in its mouth (Jared et al., 2009).

Serum Protein Profile and Blood Cell Counts in Adult Toads Bufo Arenarum (Amphibia: Anura: Bufonidae): Effects of Sublethal Lead Acetate

Abstract: Lead is a multiple-source pollutant, well known for its toxicity, of great risk both for the environment and human health. The main target organs of lead are the hematopoietic, nervous, and renal systems; there are also reports in support of its impairment effects on the reproductive and immune systems. It is well known that most of the metal is accumulated in the blood cells and that many of the deleterious effects are related to its circulating concentrations. These adverse effects have been described not only in humans but also in a number of other vertebrates such as fish and birds. The purpose of the present work was to evaluate the effects of weekly administration of sublethal Pb (as acetate, 50 mg ċ kg−1) during 6 weeks on the profile of the serum proteins and blood cell counts of the adult South American toad, Bufo arenarum (Anura: Bufonidae). The electrophoretic patterns of serum proteins pointed out the presence of four fractions; the metal provoked a significant decrease in both total proteins and albumin fraction; among the globulin fractions, the G3 resulted augmented. These findings may be related to the impact of lead on the toads’ hepatic cells and immune system. The number of total red blood cells (RBC) showed a tendency to decrease after the injections of the metal, whereas the number of white blood cells (WBC) increased significantly; the differential leukocyte counts showed a statistically significant increase in the absolute number and in the relative percentage of blast-like cells. The decrease in RBC was attributed to the negative impact of the metals on the hemoglobin synthesis. The increasing of the WBC counts may be interpreted as a consequence of the induction of proliferation of pluripotential hematopoietic cells.

Changes in the pituitary of the common toad, Bufo bufo, during metamorphosis, and the identification of the thyrotropic cells.

Abstract: Histological changes are described in the pituitary and thyroids of Bufo bufo at subsequent stages of metamorphosis Special attention is paid to the differentiation of the chromophilic cell types in the pars distalis of the adenohypophysis

cDNA cloning of a functional water channel from toad urinary bladder epithelium

Abstract: A cDNA was cloned from the epithelium of toad (Bufo marinas) urinary bladder, based on homology to the mammalian aquaporins (AQP). The cDNA [947 base pairs (bp), identified as AQP-t1] encoded a 272...