Showing papers on "Toad published in 2019"

A single inhalation of vapor from dried toad secretion containing 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) in a naturalistic setting is related to sustained enhancement of satisfaction with life, mindfulness-related capacities, and a decrement of psychopathological symptoms

Abstract: Background 5-methoxy-N,N-dimethyltryptamine (hereinafter referred to as 5-MeO-DMT) is a psychedelic substance found in the secretion from the parotoid glands of the Bufo alvarius toad. Inhalation of vapor from toad secretion containing 5-MeO-DMT has become popular in naturalistic settings as a treatment of mental health problems or as a means for spiritual exploration. However, knowledge of the effects of 5-MeO-DMT in humans is limited.

Induction of hyperpigmentation and heat shock protein 70 response to the toxicity of methomyl insecticide during the organ development of the Arabian toad, Bufo arabicus (Heyden,1827)

Abstract: Methomyl (MET) is a carbamate insecticide which is used as a substitute for organophosphorus compounds to protect crops against insects. The present study aims to evaluate the cytoprotection response of pigment cells and heat shock protein 70 (HSP70) after exposure to MET during the tadpole developmental stages of the Arabian toad, Bufo arabicus. Three developmental larval stages of the toad were selected and divided into two groups; Control and MET-exposed (MET-EX) tadpoles (10ppm). MET-EX tadpoles showed an increased number of pigment cells in the liver, kidney, anterior eye chamber, and skin tissues as compared to the control. The glycogen content in the developing liver and muscles (myotomes) of MET-EX tadpoles was decreased as compared to the control. In the MET-EX tadpoles, immunohistochemical staining showed an increase of HSP70 expression in the liver hepatocytes, the nucleated red blood cells (nRBC) in kidney glomeruli, the iridocorneal angle of anterior eye chamber, and the skin as compared to the control. The current study concluded that pigment cells and HSP70 represented a cytoprotecting response against MET insecticide during the organ development of B. arabicas tadpoles. Therefore, MET use should be regularly monitored in the environment to protect animals and human from exposure to this insecticide.

Effect of glucocorticoids on androgen biosynthesis in the testes of the toad Rhinella arenarum (Amphibia, Anura).

Abstract: In rat Leydig cells, glucocorticoids (GCs) inhibit testosterone production through the interaction with the glucocorticoid receptor (GR). However, the sensitivity of those cells to GCs is regulated by the enzyme 11β-hydroxysteroid dehydrogenase Type 1 (11β-HSD1). In the testes of the toad Rhinella arenarum, the presence of an 11β-HSD similar to type 2 and a cytosolic GR has also been described. However, there is a lack of information regarding the effects of GCs on amphibian testicular steroidogenesis. In this study, the effects of corticosterone on androgen production, and the activity of two steroidogenic enzymes in toad testes were reported. Corticosterone inhibits androgen production via the GR because the GR antagonist RU486 prevents corticosterone-induced inhibition of testosterone. Corticosterone also reduced the activity of the cytochrome P450 17-hydroxylase, C17,20-lyase (Cyp450 c17) without affecting the 3β-hydroxysteroid dehydrogenase/isomerase activity. This effect on Cyp450 c17 was likewise inhibited by RU486. On the other hand, corticosterone had no effect on the amount of steroidogenic acute regulator protein. These results suggest that GCs inhibit steroidogenesis in toad testes by reducing of Cyp450 c17 activity via a GR-mediated mechanism. © 2018 Wiley Periodicals, Inc.

Competitively mediated changes in male toad calls can depend on call structure

Abstract: Males of many species aggregate in large groups where they signal to attract females. These large aggregations create intense competition for mates, and the simultaneous signaling by many individuals can impair any given male’s ability to attract females. In response to this situation, male signals can be modified, either evolutionarily or facultatively, such that the detectability of the signal is enhanced. The way in which signals are modified varies among even closely related species, yet few studies have evaluated what causes such variation. Here, we address this issue using male spadefoot toads (Spea multiplicata and Spea bombifrons), which call to attract females. Using data from natural populations, we examined if, and how, male calls of 3 different call types (S. multiplicata with a slow call, S. bombifrons with a slow call, and S. bombifrons with a fast call) varied depending on competition with other males. We found that in both call types consisting of slow calls, call pulse rate decreased with increasing competition. By contrast, in the call type consisting of fast calls, call rate decreased with increasing competition. Moreover, we found that the relationship between competition and male call effort—a measure of the energy that males expend in calling––differed between the call types. Such variation in male signals in response to competition can have important implications for explaining diversity in male signals and patterns of sexual selection.

Assessment of neuropharmacological potential of low molecular weight components extracted from Rhinella schneideri toad poison

Abstract: Background: Studies on toad poison are relevant since they are considered a good source of toxins that act on different biological systems. Among the molecules found in the toad poison, it can be highlighted the cardiotonic heterosides, which have a known mechanism that inhibit Na+/K+-ATPase enzyme. However, these poisons have many other molecules that may have important biological actions. Therefore, this work evaluated the action of the low molecular weight components from Rhinella schneideri toad poison on Na+/K+-ATPase and their anticonvulsive and / or neurotoxic effects, in order to detect molecules with actions of biotechnological interest. Methods: Rhinella schneideri toad (male and female) poison was collected by pressuring their parotoid glands and immediately dried and stored at -20 °C. The poison was dialysed and the water containing the low molecular mass molecules (< 8 kDa) that permeate the dialysis membrane was collected, frozen and lyophilized, resulting in the sample used in the assays, named low molecular weight fraction (LMWF). Na+/K+ ATPase was isolated from rabbit kidneys and enzyme activity assays performed by the quantification of phosphate released due to enzyme activity in the presence of LMWF (1.0; 10; 50 and 100 µg/mL) from Rhinella schneideri poison. Evaluation of the L-Glutamate (L-Glu) excitatory amino acid uptake in brain-cortical synaptosomes of Wistar rats was performed using [3H]L-glutamate and different concentration of LMWF (10-5 to 10 µg/µL). Anticonvulsant assays were performed using pentylenetetrazole (PTZ) and N-methyl-D-aspartate (NMDA) to induce seizures in Wistar rats (n= 6), which were cannulated in the lateral ventricle and treated with different concentration of LMWF (0.25; 0.5; 1.0; 2.0; 3.0 and 4.0 µg/µL) 15 min prior to the injection of the seizure agent. Results: LMWF induced a concentration-dependent inhibition of Na+/K+-ATPase (IC50% = 107.5 μg/mL). The poison induces an increased uptake of the amino acid L-glutamate in brain-cortical synaptosomes of Wistar rats. This increase in the L-glutamate uptake was observed mainly at the lowest concentrations tested (10-5 to 10-2 µg/µL). In addition, this fraction showed a very relevant central neuroprotection on seizures induced by PTZ and NMDA. Conclusions: LMWF from Rhinella schneideri poison has low molecular weight compounds, which were able to inhibit Na+/K+-ATPase activity, increase the L-glutamate uptake and reduced seizures induced by PTZ and NMDA. These results showed that LMWF is a rich source of components with biological functions of high medical and scientific interest.

A case study on earlier activation of the variable toad, Bufotes variabilis (Pallas, 1769)

Abstract: Amphibians are one of the most vulnerable group that are directly affected by environmental factors. Researchers report that nearly one third of species threatened with extinction. Amphibians in the temperate zone hibernate in winter season under normal conditions and fluctuations in climate impact indirectly the summer and winter activity of these ectothermic animals. In this study, we report data on the extraordinary activity of Bufotes variabilis in winter period and evaluated that variable toad could be active throughout the year due to global climate changes.

Effect of exposure to deltamethrin on the bufadienolide profiles in Bufo bufo gargarizans venom determined by ultra-performance liquid chromatography-triple quadrupole mass spectrometry

Abstract: The population of Bufo bufo gargarizans Cantor in China has been alarmingly declining due to environmental pollution. Deltamethrin is a pyrethroid pesticide frequently used in agriculture and much of its residues are present in crops, soil and water. Deltamethrin has been shown to have toxicity to toads. Herein, we assumed that deltamethrin contamination might influence the biosynthesis of toxic substances present in toad venom. Bufadienolides present in venom are the toad's chemical defense and highly toxic to predators, and they are important for the survival of toad species against predators. In this study, we determined the contents of bufadienolides in toad venom using a HPLC-triple quadrupole mass spectrometer to evaluate the change in bufadienolide profiles in toad venom before and after cutaneous exposure to deltamethrin. The results indicated that toads exposed to high concentration of deltamethrin survive the least, do not exuviate, and their movements are stiff. Furthermore, it was observed that high level of deltamethrin contamination induces a marked decrease in the levels of toxic bufadienolides in toad venom. These changes in the toxin profiles could lead to the compromised chemical defense of toad, leading to more susceptible to attack by predators. This is the first study to report that environmental contaminants (pesticides) can influence the toad's toxic profiles, suggesting one factor contributing to the decline in the population of B. bufo gargarizans Cantor.

Histological Changes in Common Toad, Bufo Bufo (Anura, Bufonidae), Liver Tissue Under Conditions of Anthropogenically Transformed Ecosystems

Abstract: Abstract In the article the histological changes in the liver of the common toad, Bufo bufo (Linnaeus, 1758), under conditions of moderate anthropogenic pollution (a vast park surrounded by urban areas) are examined. In the liver parenchyma, numerous changes characteristic of toxic damage were found: hepatocyte necrosis, fatty dystrophy, protein (and hydropic) dystrophy, signs of infl ammation. An analysis of the number of pigment inclusions in the liver shows hyperpigmentation in some specimens and hypopigmentation in others. The presence of hyperpigmentation indicates a moderate degree of damage and activation of compensation processes in animals. This is confirmed by a large population of common toads in this biotope. It is concluded that in anthropogenically modified biotopes some deterioration of animal health can be compensated by the absence of predators and the reduction of food competition.

The common toad (Bufo bufo) - dark coloration

Abstract: C anomalies in amphibians may act as bioindicators of disrupted environments (Henle et al., 2017a). Melanism (abnormally black coloration) is an anomaly that may cover part or all of the body. Its proximal cause is an over-representation of eumelanin, usually due to an excess of melanophores (Henle et al., 2017a) and a reduction of xantophores and iridophores, which may have a genetic basis linked to xanthine dehydrogenase (Bagnara et al., 1978). Melanism can be caused by UV-B radiation but natural, ambient, radiation of this type was proven to play no part in the genesis of melanism in the Common Toad (Bufo bufo) (Langhelle et al., 1999). In amphibians, melanism can be innate (hence heritable, as in Salamandra salamandra; Henle et al., 2017a), or be developed as a physiological reaction to specific conditions (as in S. keyserlingii; Henle et al., 2017b). Innate melanism can be a result of anthropogenic mutagenesis. Axanthism, on the other hand, is caused by a lack of particular pigment cells iridophores, xantophores and erythrophores (Jablonski et al., 2014). This colour anomaly, rarer than albinism or melanism, is characterised by blue/grey or dark coloration with black eyes and has been observed in Bufotes viridis (Ibid.). Full axanthism can be mistaken for melanism but axanthic specimens tend to have discernable patterns and be lighter in colour as they differ from melanistic specimens in having no overproduction of melanin (Ibid.). It is thought that both genetic and environmental factors contribute to axanthism (Ibid.). The common toad (B. bufo) is a fairly common amphibian in Poland (Juszczyk, 1986) that tolerates disturbed environments (Speybroeck et al., 2016; Kaczmarski et al., 2016). This species is common throughout almost all Europe (Speybroeck et al., 2016) and as a result it has been one of the best-studied tailless amphibians. Axanthism has been described in B. bufo (Dubois, 1969) but in the case of melanism only black spots on adult (Mattes, 2013) and juvenile (Kliemt, 2017) have been reported and it has been assumed that these were caused by a fungal disease. On the 20th of June 2011 a number of freshly metamorphosed B. bufo were seen dispersing from the banks of a body of water in an active sand and gravel quarry next to fields on the outskirts of Gorzów Wielkopolski (Western Poland)52° 46’50.6” N, 15° 14’29.1” E. A minority (>10) of them were very darktheir skin and eye colour was black and this coloration did not change over half an hour. Their behaviour was not different from that of normally-coloured toadlets and no pathological changes were seen. Histological samples were not obtained but photos were taken. A year later (11th June 2012), at the same location, another group of unusually dark freshly metamorphosed common toads was observed and photos of specimens were once again taken. In the following years, after the quarry had been shut down, no other abnormally dark specimens were observed at that site. It is suggested that the quarry may have been using chemicals that contaminated the water and caused mutations in the common toad eggs and/or adults. The disappearance of these black toads may be due to the fact that this coloration is not adaptive. Melanistic reptiles may gain thermal advantages from their coloration but this would not appear to be an advantage for toads as they do not bask in sunshine, preferring to remain at relatively low temperatures. Melanism or axanthism could be advantageous to toads that live on black backgrounds as this would provide camouflage but the habitat of this toad population did not appear to offer black backgrounds and so instead the black toads may have been at a disadvantage being more easily seen by predators.

Three-dimensional toad cultivation method

Abstract: The invention discloses a three-dimensional toad cultivation method, and belongs to the technical field of toad cultivation. The method comprises the steps that a three-dimensional toad cultivation device is composed of a toad cultivation box frame, a water circulation mechanism, a toad cultivation box, a feeding vibration mechanism and a toad cultivation box water supply pipe; toads are put intoa toad cultivation box cavity, and the feeding density of toads put into the toad cultivation box cavity is controlled according to the gram weight of each toad; a toad anti-escape mesh enclosure forpreventing toads from escaping covers and is fixedly tied to an opening in the upper portion of the toad cultivation box; in the daytime, the water circulation mechanism works, the working time of thewater circulation mechanism is controlled, at night, the water circulation mechanism is stopped from working, the water level inside the toad cultivation box cavity is controlled, the frequency of feed fed every time is controlled, and the feed feeding amount is controlled; the dried venom of toads and toad cortex are taken timely, and toads are returned to the toad cultivation box for continuouscultivation after the dried venom of toads and toad cortex are taken. The high-density three-dimensional cultivation effect is good, and the space utilization rate is high; the cultivation survival rate is increased; economic benefits are ideal.

The Role of Hormones in the Regulation of Glycogen Metabolism in the Clawed Toad Xenopus Laevis (Daudin)

Abstract: The hormonal regulation of amphibian glycogen metabolism was studied in Xenopus laevis as a typical member of the anurans (tailless amphibians).The main focus of this study was given to the effects of various hormones on the glycogen/glucose balance in adult toads. We determined biochemically the liver and muscle glycogen contents as well as the blood glucose and lipid levels for a number of hormones and also diabetes inducing substances. Additionally, we examined ultrastructure changes in hepatocytes induced by the various treatments, and also investigated the activity of carbohydrate-relevant enzymes by histochemistry. With one exception, the liver glycogen content of Xenopus remained basically unchanged by the treatments or was even slightly enhanced. Only human chorionic gonadotropin, through which the vitellogenic response is triggered, prompts a significant decrease of liver glycogen in females. Under the same conditions the male liver glycogen content remained stable. Muscle glycogen contents were not affected by any of the treatments. Blood glucose and lipid levels on the other hand were elevated considerably in both sexes after application of either epinephrine or cortisol. The ultrastructural examination revealed a proliferation of Rough Endoplasmic Reticulum (RER) in hepatocytes from epinephrine treated toads of both sexes as well as from HCG treated females. By histochemistry, we detected an elevated glucose-6-phosphatase activity in the hepatocytes from toads treated with either epinephrine or cortisol. These treatments also led to enhanced glycogen phosphorylase activity in males, and to a slightly elevated glyceraldehyde-3-phosphate dehydrogenase activity in females. Our results show that the hepatic glycogen is extremely stable in adult Xenopus. Only vitellogenesis causes a marked utilization of glycogen. Since the blood glucose levels are elevated in epinephrine or cortisol treated toads without the liver glycogen being affected, we conclude that either protein and/or lipid metabolism are involved in carbohydrate metabolism in Xenopus laevis.