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Sample records for natterjack toad bufo

  1. Microsatellite analysis of the natterjack toad (Bufo calamita) in Denmark: populations are islands in a fragmented landscape

    DEFF Research Database (Denmark)

    Allentoft, Morten Erik; Siegismund, Hans Redlef; Briggs, Lars;

    2009-01-01

    The European natterjack toad (Bufo calamita) has declined rapidly in recent years, primarily due to loss of habitat, and in Denmark it is estimated that 50% of the isolated populations are lost each decade. To efficiently manage and conserve this species and its genetic diversity, knowledge...

  2. Drift rather than selection dominates MHC class II allelic diversity patterns at the biogeographical range scale in natterjack toads Bufo calamita.

    Directory of Open Access Journals (Sweden)

    Inga Zeisset

    Full Text Available Study of major histocompatibility complex (MHC loci has gained great popularity in recent years, partly due to their function in protecting vertebrates from infections. This is of particular interest in amphibians on account of major threats many species face from emergent diseases such as chytridiomycosis. In this study we compare levels of diversity in an expressed MHC class II locus with neutral genetic diversity at microsatellite loci in natterjack toad (Bufo (Epidalea calamita populations across the whole of the species' biogeographical range. Variation at both classes of loci was high in the glacial refugium areas (REF and much lower in postglacial expansion areas (PGE, especially in range edge populations. Although there was clear evidence that the MHC locus was influenced by positive selection in the past, congruence with the neutral markers suggested that historical demographic events were the main force shaping MHC variation in the PGE area. Both neutral and adaptive genetic variation declined with distance from glacial refugia. Nevertheless, there were also some indications from differential isolation by distance and allele abundance patterns that weak effects of selection have been superimposed on the main drift effect in the PGE zone.

  3. Effects of temperature on embryonic and larval development and growth in the natterjack toad (Bufo calamita in a semi-arid zone

    Directory of Open Access Journals (Sweden)

    Sanuy, D.

    2008-06-01

    Full Text Available Temperature affects the duration of embryonic and larval periods in amphibians. Plasticity in time to metamorphosis is especially important in amphibian populations of Mediterranean semi-arid zones where temperatures are high and precipitation is low, increasing the rate of pond desiccation. In order to test the influence of water temperature on the larval development and growth of the natterjack toad (Bufo calamita, we collected two spawns in a semi¿arid zone at Balaguer (Lleida, NE Iberian peninsula. Approximately 50 (+/-10 eggs (stage 14-16 were raised in the lab at different temperature conditions: 10, 15, 20, 22.5 and 25ºC with 12:12 photoperiod. The results show a lengthening of development time with decreasing temperatures and a better survival performance of B. calamita to high temperatures. However, mean size at metamorphosis was not different across treatments, thus, suggesting that this population of B. calamita requires a minimum size to complete the metamorphosis. This study is the first approach to examine the effects that climatic factors have on the growth and development of B. calamita in semi-arid zones.

  4. Conservation genetics of an island toad: Bufo bufo in Jersey

    OpenAIRE

    John W. Wilkinson; Trevor J C Beebee; Griffiths, Richard A.

    2007-01-01

    On Jersey (British Channel Islands), common toads often reproduce in small, urban ponds. This atypical breeding strategy has implications for their persistence and they have declined on the island in recent times. We used polymorphic microsatellite markers to compare genetic diversity in Bufo bufo from five different ponds in Jersey with two populations from north-west France. Genetic diversity of Jersey toads was comparable with that of populations elsewhere in Europe. Numbers of breeding fe...

  5. Thyroid anatomy and topography of toad (Bufo marinus ictericus)

    International Nuclear Information System (INIS)

    The autoradiographic method is used for the study of the toad's thyroid of Bufo marinus ictericus by 131I. Histolological proceedings are done. Comparative evaluations with bibliographic informations are presented. (M.A.C.)

  6. Final Critical Habitat for the Houston toad (Bufo houstonensis)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — To provide the user with a general idea of areas where final critical habitat for Houston toad (Bufo houstonensis) based on the description provided in the Federal...

  7. Determinants of Instrumental Extinction in Terrestrial Toads ("Bufo arenarum")

    Science.gov (United States)

    Muzio, Ruben N.; Ruetti, Eliana; Papini, Mauricio R.

    2006-01-01

    Previous research in a water-reinforced instrumental training situation with toads ("Bufo arenarum") has shown that performance in both acquisition and extinction is poorer after partial, rather than continuous reinforcement training. In Experiment 1, the performance of a group receiving 24 trials on a 50% partial reinforcement schedule was poorer…

  8. Behavior of toads, Bufo bufo, in a dynamic environment.

    Science.gov (United States)

    Lychakov, D V

    2009-01-01

    Susceptibility to motion sickness was tested by exposing free moving toads to rotation of a stimulator modeled after an amusement park Ferris Wheel. The stimulator provided a gentle stimulation of frequency 0.25 Hz and centrifugal acceleration 0.143 g during 120 min or more without external visual cues. No emetic or prodromal behavioral response was elicited during or after rotation. During rotation the amount of motor activity in most toads increased evidently. The most active toads attempted to climb out of the test chamber. It was inferred that experimental rotation was rather a stressful stimulus which initiated an escape response. In addition, during rotation the number of eye retractions and urination incidences increased, but appetite after rotation was inhibited. During rotation the motionless toads performed small regular head movements with period equal to rotation period of stimulator. These oscillations were probably vestibular (otolith) reaction to oscillating acceleration. The proposed resonance hypothesis gives a general idea of why lower vertebrates are immune to motion sickness.

  9. Kinematics of Chinese toad Bufo gargarizans

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A three-dimensional motion force tester for animal was used to measure the reaction forces of the feet of a Chinese toad (B. gargarizans) against a horizontal solid surface on which it crawled. The motion behavior of the Chinese toad was recorded by a high-speed camera on line. The motor function of every foot was analyzed. It was found that the lateral force represents the control ability of side-to-side locomotion, controls the lateral movement, and maintains a stable state for the sustainable creeping gesture. The forefeet play the assistant role and the hind feet play the main role in driving. The normal force of the forefeet is significantly greater than that of the hind feet, so the forefeet play the main role in supporting the body and the hind feet play the assistant role. The normal force is significantly greater than the lateral force and the driving force as well. There is little change for the friction force and the support angle of the all four feet. The average value of the support angle is 70°–80°. The Chinese toad’s vola friction coefficient of the forefeet is less than that of the hind feet. The above results indicate that the difference in kinematics and the material characteristic of the contact skin of the Chinese toad. The results could be useful to the structure design and gait optimization of some robots.

  10. Intoxicación aguda en perro por toxinas de sapo (Bufo bufo - Acute intoxication in a dog by toxins of a toad (Bufo bufo

    Directory of Open Access Journals (Sweden)

    Fernández-Palacios, O´Connor, Rocío

    2009-04-01

    Full Text Available ResumenLas intoxicaciones por toxinas de sapo no son frecuentes en España y su incidencia es mayor en primavera y verano. En este trabajo describimos un caso de intoxicación aguda de una perra de 4 años de edad tras la aprehensión de un sapo (Bufo bufo en la zona de Huelva. Los signos de una intoxicación comenzaron a los 15 minutos de entrar en contacto con el sapo muriendo a las 3 horas sin responder al tratamiento suministrado (corticoides, atropina, fluidoterapia y acepromazina. Aunque el diagnóstico fue precoz, a pesar del tratamiento se produjo la muerte en 3 horas.SummaryIntoxications by toad toxins are not frequent in Spain, and its incidence is greater in spring and summer. In this work it is described a case of an acute intoxication of a dog of 4 years old by toad toxins (Bufo bufo in the area of Huelva. The animal began to show signs of intoxication 15 minutes after the contact with the toad, dying 3 hours later without any response to the provided treatment (corticoids, atropine, fluidotherapy and acepromazine. Although the diagnosis was precocious and the treatment was administrated, after 3 hours the animal died.

  11. Diazinon mediated biochemical changes in the African toad (Bufo regularis

    Directory of Open Access Journals (Sweden)

    Isioma Tongo

    2012-07-01

    Full Text Available The sublethal toxicity of diazinon to the adult African toad, Bufo regularis was assessed using an integration of biomarkers. Changes in acetylcholinesterase (AChE, corticosterone and total protein levels were assessed in the serum, brain, liver, lungs and gastrointestinal tract (GIT and the results supported by bioaccumulation data. The biomarkers were chosen as indicators of key physiological functions: AChE for neurotoxicity, corticosterone and total protein levels as indicators of oxidative stress. Toads were exposed to 0.01, 0.02, 0.03 and 0.04 g/L for 28 days. Brain AChE activity reduced by 96% in the highest concentration (0.04 g/L compared to the control brain. Similarly, AChE activities in serum, liver, lungs and GIT tissues (88%, 88%, 87, 87% umg-1 protein respectively were also inhibited in the toads. Corticosterone and total protein levels in the tissues decreased compared to the control. The accumulation results obtained showed accumulation in the tissues (liver>serum>brain> lung>GIT, with a direct relationship between tissue concentration and changes in the biochemical indices. The alterations in all the indices were significantly concentration dependent. The biomarkers described in this study could be useful complementary indices in the risk assessment of diazinon pesticide.

  12. Shifts in life history as a response to predation in western toads (Bufo boreas)

    OpenAIRE

    Chivers, Douglas P.; Marco, Adolfo; Kiesecker, Joseph M.; Wildy, Erica L.; Andrew R. Blaustein

    1999-01-01

    Larval western toads (Bufo boreas) are known to exhibit antipreda­ tor behavior in response to both chemical alarm cues released from injured conspecifics and chemical cues of predatory invertebrates. In this study, we tested whether long-term exposure to predator and alarm cues resulted in an adaptive shift in life history characteristics of the toads. We raised groups of tadpoles in the presence of: (1) predatory backswimmers (Notonecta spp.) that were fed toad tadpoles, (2) nonpredatory w...

  13. The induction of neoplastic lesions by aflatoxin-B1 in the Egyptian toad (Bufo regularis).

    Science.gov (United States)

    el-Mofty, M M; Sakr, S A

    1988-01-01

    The carcinogenic activity of aflatoxin-B1, the metabolic product of the mold Aspergillus flavus (a commonly occurring contaminant of groundnuts and other foodstuffs), was tested using the Egyptian toad (Bufo regularis). Injecting the toads with aflatoxin-B1 at a dose level of 0.01 mg/50 g body wt in 1 ml corn oil once a week for 15 weeks induced hepatocellular carcinomas in 19% of the experimental toads. Four toads developed tumors in the kidney due to metastases from the primary hepatocellular carcinomas.

  14. DIET OF THE SOUTHERN TOAD (BUFO TERRESTRIS) FROM THE SOUTHERN EVERGLADES

    Science.gov (United States)

    We examined the diet of a February-May sample of the southern toad (Bufo terrestris) from the Everglades National Park. Above the familial level, 13 taxa were consumed, but ants (Hymenoptera) and beetles (Coleoptera) were consumed most by, and in the greatest number of sto...

  15. Influence of dissolved oxygen conditions on toxicity of ammonium nitrate to larval natterjack toads.

    Science.gov (United States)

    Ortiz-Santaliestra, Manuel E; Marco, Adolfo

    2015-07-01

    Temporary ponds, where many amphibians from temperate regions breed, show an annual cycle with a maximum water volume in spring followed by a progressive desiccation throughout late spring and summer. This desiccation leads to a decrease in dissolved oxygen and an increase in nitrogen levels, which can additionally increase because of anthropogenic sources such as chemical fertilizers. We analyzed the toxicity posed by environmentally relevant levels of a common nitrogenous fertilizer, ammonium nitrate, at different conditions of oxygen availability to Bufo calamita tadpoles, which typically develop in ephemeral ponds. Ammonium nitrate (90.3 mg N-NO3NH4/l) and hypoxic conditions (initial dissolved oxygen 4.53 ± 0.40 mg/l) caused significant lethal effects after 7 and 12 days of exposure, respectively. At the end of experiment (16 days), mortality rates were 32.5 % in individuals exposed to the fertilizer and 15 % in those growing under hypoxic conditions. When both stressors were combined, they showed an additive effect on tadpole survival. Malformations, such as oedemas and spinal curvatures, and locomotory abnormalities, were detected after 12 days of experiment in >90 % of individuals exposed to 45.2 mg N-NO3NH4/l under hypoxic conditions, whereas none of these stressors by separate related to abnormality rates >35 %. Delayed development was also observed in tadpoles exposed to ammonium nitrate with hypoxia affecting developmental rate only after 12 days of exposure. The results are discussed in terms of potential mechanisms linking negative effects of both factors as well as in terms of potential alterations of the ecological plasticity that often allows amphibians to survive in unpredictable environments. PMID:25586169

  16. Population and habitat viability assessment for the Wyoming toad (Bufo baxteri): Final workshop report

    Science.gov (United States)

    2001-01-01

    The Wyoming toad was discovered by Dr. George Baxter in 1946 and was originally known as Bufo hemiophrys baxteri until 1998 when it was given full species status as Bufo baxteri. The toad is thought to be a glacial relic always found only in the Laramie Basin. It was originally known from many breeding sites in the floodplains of the Big and Little Laramie Rivers. Later, after irrigation practices changed the nature of the floodpains, it was found along margins of ponds and small seepage lakes between 7,000 and 7,500 feet. Baxter and others monitored breeding sites for more than 30 years, with few toads seen or heard from 1975 to 1979. An extensive survey of the Laramie Basin in 1980 found only one population.

  17. Determination of impacts on the endangered Wyoming toad (Bufo baxteri) at Mortenson National Wildlife Refuge from ammonium nitrate concentrations

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The endangered Wyoming toad (Bufo baxteri) is found only as a reintroduced population at Mortenson NWR in the Laramie Plains of southeast Wyoming. Reasons for the...

  18. Effects of age, weight, hormones, and hibernation on breeding success in boreal toads (Bufo boreas boreas).

    Science.gov (United States)

    Roth, T L; Szymanski, D C; Keyster, E D

    2010-03-01

    The goals of this study were to test the effects of exogenous hormones and hibernation on breeding behavior and gamete release by boreal toads (Bufo boreas boreas). Each year, a subset of 77 toads was hibernated and then paired with hibernated or nonhibernated mates and treated with luteinizing hormone releasing hormone analogue (LHRHa), human chorionic gonadotropin (hCG), or left untreated. Amplexus and egg and sperm production were recorded. At 1 yr of age, only 19% of pairs exhibited amplexus, and no sperm or eggs were produced. At 2 and 3 yr of age, most male toads treated with LHRHa exhibited amplexus (56.9% and 100%, respectively). Among 2-yr-old males, amplexus was more prevalent (Pbreeding success, males should be hibernated and treated with LHRHa. In contrast, female productivity was enhanced by improving their body condition instead of subjecting them to hibernation prior to LHRHa treatment.

  19. Effects of a glyphosate-based herbicide on the development of Common toads (Bufo bufo L.; Amphibia) at different temperatures

    Science.gov (United States)

    Baier, Fabian; Gruber, Edith; Spangl, Bernhard; Zaller, Johann G.

    2016-04-01

    Herbicides based on the active ingredient glyphosate are frequently applied in agriculture, horticulture and private gardens all over the world. Recently, leaching of glyphosate or its metabolite (AMPA) into water bodies inhabited by amphibians has been reported. However, very little is known about non-target effects of these herbicides on amphibians and even less is known to what extent different temperatures might alter these effects. Using climate chambers, we investigated the effects of the glyphosate-based herbicide Roundup PowerFlex® (480 g L-1 glyphosate, formulated as 588 g L-1 potassium salt) on the larval development of Common toads (Bufo bufo L.; Amphibia: Anura) under different temperature regimes (15°C vs. 20°C). We established five herbicide concentrations: 0, 1.5, 3, 4 mg acid equivalent L-1 and a 4 mg a.e. L-1 pulse treatment (totally three applications of 1.5, 1.5 and another 1 mg a.e. L-1) at each temperature in a full-factorial design. Each treatment combination was replicated five times, the experiment ran for 24 days. Results showed a highly significant effect of temperature on body length and body width but no effect of herbicide concentration on these growth parameters. Moreover, highly significant interactions between herbicide and temperature on body length and body width were observed suggesting that herbicides had different effects on different temperatures. In conclusion, although Roundup PowerFlex® at the tested concentrations appeared to have no acute toxicity to larvae of Common toads, the observed effects on tadpole morphology will potentially affect competitive interactions in spawning ponds of amphibia. Our findings of herbicide x temperature interactions might become more prevalent when human-induced climate change will lead to more extreme temperatures.

  20. Variation in Chemical Defense Among Natural Populations of Common Toad, Bufo bufo, Tadpoles: the Role of Environmental Factors.

    Science.gov (United States)

    Bókony, Veronika; Móricz, Ágnes M; Tóth, Zsófia; Gál, Zoltán; Kurali, Anikó; Mikó, Zsanett; Pásztor, Katalin; Szederkényi, Márk; Tóth, Zoltán; Ujszegi, János; Üveges, Bálint; Krüzselyi, Dániel; Capon, Robert J; Hoi, Herbert; Hettyey, Attila

    2016-04-01

    Defensive toxins are widespread in nature, yet we know little about how various environmental factors shape the evolution of chemical defense, especially in vertebrates. In this study we investigated the natural variation in the amount and composition of bufadienolide toxins, and the relative importance of ecological factors in predicting that variation, in larvae of the common toad, Bufo bufo, an amphibian that produces toxins de novo. We found that tadpoles' toxin content varied markedly among populations, and the number of compounds per tadpole also differed between two geographical regions. The most consistent predictor of toxicity was the strength of competition, indicating that tadpoles produced more compounds and larger amounts of toxins when coexisting with more competitors. Additionally, tadpoles tended to contain larger concentrations of bufadienolides in ponds that were less prone to desiccation, suggesting that the costs of toxin production can only be afforded by tadpoles that do not need to drastically speed up their development. Interestingly, this trade-off was not alleviated by higher food abundance, as periphyton biomass had negligible effect on chemical defense. Even more surprisingly, we found no evidence that higher predation risk enhances chemical defenses, suggesting that low predictability of predation risk and high mortality cost of low toxicity might select for constitutive expression of chemical defense irrespective of the actual level of predation risk. Our findings highlight that the variation in chemical defense may be influenced by environmental heterogeneity in both the need for, and constraints on, toxicity as predicted by optimal defense theory. PMID:27059330

  1. Inducement of Sechenov inhibition by EtOH and NA in the Bufo toad

    Institute of Scientific and Technical Information of China (English)

    LI RuXin; JIA ShanShan; LI YingZi; CAO Yin; CHENG XiuZhen; XIE ZuoPing

    2008-01-01

    Central inhibition, discovered by Sechenov in 1862, suggests that electrically stimulating the forebrain or medulla oblongata in frog generally suppresses reflexes. However, the underlying molecular mechanisms are still unclear. Using ethanol (EtOH), noradrenalin (NA), and other neurotransmitters in thalamic preparations, Sechenov inhibition was stimulated in Bufo toads in this study. The result showed that, similar to Sechenov inhibition, the acute application of EtOH or NA excited the thalamus and prolonged the latency of withdrawal reflex. Our study evidences the involvement of α-adrenoceptors in such central inhibition, and explains the role of acute EtOH application in the in-duction of reflex inhibition.

  2. Ion transport mechanisms in the mesonephric collecting duct system of the toad Bufo bufo: microelectrode recordings from isolated and perfused tubules

    DEFF Research Database (Denmark)

    Møbjerg, Nadja; Larsen, Erik Hviid; Novak, Ivana

    2004-01-01

    It is not clear how and whether terrestrial amphibians handle NaCl transport in the distal nephron. Therefore, we studied ion transport in isolated perfused collecting tubules and ducts from toad, Bufo bufo, by means of microelectrodes. No qualitative difference in basolateral cell membrane...... and amiloride application showed a small apical Na+ conductance. Arginine vasotocin depolarized Vbl. The small apical Na+ conductance indicates that the collecting duct system contributes little to NaCl reabsorption when compared to aquatic amphibians. In contrast, Vbl rapidly depolarized upon lowering of [Na...

  3. Diagnostic histological findings in Yosemite toads (Bufo canorus) from die-off in the 1970s

    Science.gov (United States)

    Green, D.E.; Sherman, C.K.

    2001-01-01

    Twelve adult and 25 larval Yosemite toad (Bufo canorus) specimens from the eastern Sierra Nevada of California were examined histologically for evidence of infectious, toxicological, and degenerative diseases. The preserved toads were selected from 21 that had been salvaged or collected during a die-off in 1976-1979 that immediately preceded a population decline. Causes of death of four toads were determined histologically; clinical signs and field observations suggested causes of death of three more. Four toads died of infectious diseases, including chytridiomycosis of the skin (N = 1), bacillary septicemia (N = 2), and combined chytridiomycosis and bacterial septicemia (N = 1). Infections by a funguslike organism (Dermosporidium penneri), renal myxozoa (Leptotheca ohlmacheri), larval Rhabdias, various gastrointestinal nematodes, urinary bladder flukes, and lung flukes were detected in five specimens. No evidence of degenerative diseases, virus infections, or intoxications was found. The variety of lethal diseases and our inability to determine the causes of death of five specimens suggests that one or more histologically undetectable diseases or intoxications may have also contributed to the deaths and population decline.

  4. Ultrastructure of the renal juxtaglomerular complex and peripolar cells in the axolotl (Ambystoma mexicanum) and toad (Bufo marinus).

    Science.gov (United States)

    Hanner, R H; Ryan, G B

    1980-05-01

    Renal juxtaglomerular regions were examined in the axolotl (Ambystoma mexicanum and toad (Bufo marinus). Prominent granulated peripolar epithelial cells were found surrounding the origin of the glomerular tuft in the axolotl. These cells resembled the peripolar cells recently discovered in mammalian species. They contained multiple electron-dense cytoplasmic granules, some of which showed a paracrystalline substructure and signs of exocytoxic activity. Such cells were difficult to find and smaller in the toad. In contrast, granulated juxtaglomerular arteriolar myoephithelial cells were much more readily found and larger in the toad than in the axolotl. No consistent differences were noted in juxtaglomerular cells or their granules in response to changes in environmental chloride concentration.

  5. Screening breeding sites of the common toad (Bufo bufo) in England and Wales for evidence of endocrine disrupting activity.

    Science.gov (United States)

    Pickford, Daniel B; Jones, Alexandra; Velez-Pelez, Alejandra; Orton, Frances; Iguchi, Taisen; Mitsui, Naoko; Tooi, Osamu

    2015-07-01

    Anuran amphibians are often present in agricultural landscapes and may therefore be exposed to chemicals in surface waters used for breeding. We used passive accumulation devices (SPMD and POCIS) to sample contaminants from nine breeding sites of the Common toad (Bufo bufo) across England and Wales, measuring endocrine activity of the extracts in a recombinant yeast androgen screen (YAS) and yeast estrogen screen (YES) and an in vitro vitellogenin induction screen in primary culture of Xenopus laevis hepatocytes. We also assessed hatching, growth, survival, and development in caged larvae in situ, and sampled metamorphs for gonadal histopathology. None of the SPMD extracts exhibited estrogen receptor or androgen receptor agonist activity, while POCIS extracts from two sites in west-central England exhibited concentration-dependent androgenic activity in the YAS. Three sites exhibited significant estrogenic activity in both the YES and the Xenopus hepatocyte. Hatching rates varied widely among sites, but there was no consistent correlation between hatching rate and intensity of agricultural activity, predicted concentrations of agrochemicals, or endocrine activity measured in YES/YAS assays. While a small number of intersex individuals were observed, their incidence could not be associated with predicted pesticide exposure or endocrine activitity measured in the in vitro screens. There were no significant differences in sex ratio, as determined by gonadal histomorphology among the study sites, and no significant correlation was observed between proportion of males and predicted exposure to agrochemicals. However, a negative correlation did become apparent in later sampling periods between proportion of males and estrogenic activity of the POCIS sample, as measured in the YES. Our results suggest that larval and adult amphibians may be exposed to endocrine disrupting chemicals in breeding ponds, albeit at low concentrations, and that chemical contaminants other than

  6. Efficacy of fenbendazole and levamisole treatments in captive Houston toads (Bufo [Anaxyrus] houstonensis).

    Science.gov (United States)

    Bianchi, Catherine M; Johnson, Cassidy B; Howard, Lauren L; Crump, Paul

    2014-09-01

    Effective disease monitoring and prevention is critical to the success of captive amphibian care. Nematodes, including the genera Rhabdias and Strongyloides, are known to contribute to mortality in captive amphibians and have been identified in the Houston Zoo's endangered Houston toad (Bufo [Anaxyrus] houstonensis) captive assurance colony. Five years of fecal data for the toad colony were compiled and analyzed in order to investigate the efficacy of two anthelminthic medications, fenbendazole (FBZ) and levamisole (LMS), which were used to control nematode infections. Both FBZ (dusted onto food items) and topical LMS (6.5 to 13.5 mg/kg) significantly reduced the number of nematode eggs, larvae, and adults observed by fecal parasitologic examination. There were no significant differences between treatments, and egg reappearance periods were difficult to compare as a result of low sample size. No adverse effects from either anthelminthic treatment were observed. Both topical LMS and oral FBZ appear to be safe and efficacious treatments for the reduction of the internal nematode burden in captive Houston toads.

  7. The osmotic behaviour of toad skin epithelium (Bufo viridis). an electron microprobe analysis.

    Science.gov (United States)

    Rick, R; Dörge, A; Katz, U; Bauer, R; Thurau, K

    1980-05-01

    The effect of saline adaptation on the intracellular Na, K, Cl, P concentrations and dry weight content of the toad skin epithelium (Bufo viridis) was studied using the technique of electron microprobe analysis. The measurements were performed on isolated abdominal skins either directly after dissection or after additional incubation in Ussing-type chambers. Adaptations of the toads to increasing NaCl concentrations for 7 days resulted in increased blood plasma osmolarity and a parallel increase in the cellular electrolyte, P and dry weight concentrations of the epithelium, the K increase representing the most significant fraction of the intracellular osmolarity increase. No evidence was obtained to show that the nucleus and cytoplasm reacted differently from each other and all living epithelial cell types basically showed the same response. Incubation of the isolated skins under control conditions showed a drastic inhibition of the transepithelial Na transport after adaptation to high salinities. In spite of the large variations in the transport rate almost identical intracellular electrolyte concentrations were observed. In tap water adapted toads the average cellular concentrations were 8.8 mmole/kg wet weight for Na, 109.6 for K, 41.5 for Cl, and 135.3 for P, respectively. Incubation of the skin with Ringer's solution of different osmolarities demonstrated that the epithelial cells are in osmotic equilibrium with the inner bathing solution. The results are consistent with the view that the osmotic adaptation is mainly accomplished by the movement of water. PMID:7191092

  8. Behavioral response and kinetics of terrestrial atrazine exposure in American toads (bufo americanus)

    Science.gov (United States)

    Storrs, Mendez S.I.; Tillitt, D.E.; Rittenhouse, T.A.G.; Semlitsch, R.D.

    2009-01-01

    Amphibians in terrestrial environments obtain water through a highly vascularized pelvic patch of skin. Chemicals can also be exchanged across this patch. Atrazine (ATZ), a widespread herbicide, continues to be a concern among amphibian ecologists based on potential exposure and toxicity. Few studies have examined its impact on the terrestrial juvenile or adult stages of toads. In the current study, we asked the following questions: (1) Will juvenile American toads (Bufo americanus) avoid soils contaminated with ATZ? (2) Can they absorb ATZ across the pelvic patch? (3) If so, how is it distributed among the organs and eventually eliminated? We conducted a behavioral choice test between control soil and soil dosed with ecologically relevant concentrations of ATZ. In addition, we examined the uptake, distribution, and elimination of water dosed with 14C-labeled ATZ. Our data demonstrate that toads do not avoid ATZ-laden soils. ATZ crossed the pelvic patch rapidly and reached an apparent equilibrium within 5 h. The majority of the radiolabeled ATZ ended up in the intestines, whereas the greatest concentrations were observed in the gall bladder. Thus, exposure of adult life stages of amphibians through direct uptake of ATZ from soils and runoff water should be considered in risk evaluations. ?? 2009 Springer Science+Business Media, LLC.

  9. Vasculature of the parotoid glands of four species of toads (bufonidae: bufo).

    Science.gov (United States)

    Hutchinson, Deborah A; Savitzky, Alan H

    2004-05-01

    The parotoid glands of toads (Bufonidae) consist of large aggregations of granular glands located between the otic region of the skull and the scapular region. To determine the circulatory pattern of these glands, we perfused the vascular systems of Bufo alvarius, B. marinus, B. terrestris, and B. valliceps with either India ink or Microfil, a fine latex. The perfused glands were studied by gross dissection, microscopic examination, and histology. The vascular patterns of the parotoid glands were compared to the arrangement of vessels in the dorsal skin of Rana sphenocephala (Ranidae), a frog that lacks parotoid glands. The parotoid glands of the four species of toads are supplied with blood by the lateral and dorsal cutaneous arteries and are drained by one or more branches of the internal jugular vein. The dorsal cutaneous artery supplies most of the blood to the parotoid glands in B. terrestris and B. valliceps. In B. alvarius and B. marinus, both the lateral and dorsal cutaneous arteries serve major roles in the blood supply of the glands. These patterns of blood flow have not been described previously for parotoid glands and conflict with earlier accounts for B. alvarius and B. marinus. The arteries and veins associated with the parotoid glands of toads are present in R. sphenocephala, but are arranged differently. In R. sphenocephala, the lateral cutaneous artery supplies the dorsal and lateral skin posterior to the shoulder region, whereas the dorsal cutaneous artery supplies the skin of the shoulder region. In toads, both the lateral and dorsal cutaneous arteries supply the skin of the shoulder region and ramify into subcutaneous capillaries that surround the secretory units of the parotoid glands. Extensive vasculature presumably is important for delivering cholesterol and other precursor molecules to the parotoid glands, where those compounds are converted into toxins.

  10. Natural and experimental infection of the lizard Ameiva ameiva with Hemolivia stellata (Adeleina: Haemogregarinidae) of the toad Bufo marinus

    OpenAIRE

    Lainson R.; De Souza M.C.; Franco C.M.

    2007-01-01

    Developmental stages of a haemogregarine in erythrocytes of the lizard Ameiva ameiva (Teiidae), from Pará State, north Brazil, were shown to be those of Hemolivia by the nature of the parasite’s sporogonic cycle in the tick Amblyomma rotondatum. The type species, Hemolivia stellata Petit et al., 1990 was described in the giant toad Bufo marinus and the tick Amblyomma rotondatum, also from Pará State, and in view of the fact that A. ameiva and Bufo marinus share the same habitat and are both c...

  11. Association preference and mechanism of kin recognition in tadpoles of the toad Bufo melanostictus

    Indian Academy of Sciences (India)

    Lilly Margaret Eluvathingal; Bhagyashri A Shanbhag; Srinivas K Saidapur

    2009-09-01

    In experiments with specially designed choice tanks, tadpoles of Bufo melanostictus spend significantly greater amounts of time near kin than near non-kin. However, in the absence of kin members, they prefer to spend more time near non-kin rather than stay away in isolation in the opposite blank zone with no company. This implies that association of toad tadpoles with their kin is due to attraction rather than repulsion from non-kin. Experiments designed to elucidate the sensory basis of kin recognition showed that toad tadpoles recognize their kin based on chemical cues rather than visual cues. They can also discriminate between homospecific non-kin and heterospecific (Sphaerotheca breviceps) tadpoles since the tadpoles spent significantly greater amounts of time near the former than near the latter. These findings suggest that where kin members are unavailable, selection may have favoured living with non-kin so as to derive benefits from group living and that a phenotype-matching mechanism may operate for both kin and species discrimination in B. melanostictus.

  12. Ultrastructure of the renal juxtaglomerular complex and peripolar cells in the axolotl (Ambystoma mexicanum) and toad (Bufo marinus).

    OpenAIRE

    Hanner, R H; Ryan, G B

    1980-01-01

    Renal juxtaglomerular regions were examined in the axolotl (Ambystoma mexicanum and toad (Bufo marinus). Prominent granulated peripolar epithelial cells were found surrounding the origin of the glomerular tuft in the axolotl. These cells resembled the peripolar cells recently discovered in mammalian species. They contained multiple electron-dense cytoplasmic granules, some of which showed a paracrystalline substructure and signs of exocytoxic activity. Such cells were difficult to find and sm...

  13. Volunteer Conservation Action Data Reveals Large-Scale and Long-Term Negative Population Trends of a Widespread Amphibian, the Common Toad (Bufo bufo)

    Science.gov (United States)

    Petrovan, Silviu O.

    2016-01-01

    Rare and threatened species are the most frequent focus of conservation science and action. With the ongoing shift from single-species conservation towards the preservation of ecosystem services, there is a greater need to understand abundance trends of common species because declines in common species can disproportionately impact ecosystems function. We used volunteer-collected data in two European countries, the United Kingdom (UK) and Switzerland, since the 1970s to assess national and regional trends for one of Europe’s most abundant amphibian species, the common toad (Bufo bufo). Millions of toads were moved by volunteers across roads during this period in an effort to protect them from road traffic. For Switzerland, we additionally estimated trends for the common frog (Rana temporaria), a similarly widespread and common amphibian species. We used state-space models to account for variability in detection and effort and included only populations with at least 5 years of data; 153 populations for the UK and 141 for Switzerland. Common toads declined continuously in each decade in both countries since the 1980s. Given the declines, this common species almost qualifies for International Union for the Conservation of Nature (IUCN) red-listing over this period despite volunteer conservation efforts. Reasons for the declines and wider impacts remain unknown. By contrast, common frog populations were stable or increasing in Switzerland, although there was evidence of declines after 2003. “Toads on Roads” schemes are vital citizen conservation action projects, and the data from such projects can be used for large scale trend estimations of widespread amphibians. We highlight the need for increased research into the status of common amphibian species in addition to conservation efforts focusing on rare and threatened species. PMID:27706154

  14. The dynamics of venous return and response to hypervolemia in the toad, Bufo marinus (L.

    Directory of Open Access Journals (Sweden)

    Toews Daniel P

    2001-10-01

    Full Text Available Abstract Background Venous return from the posterior region of amphibians travels by either two renal portal veins to the kidney or a central abdominal vein that drains into the hepatic portal system. The relative proportions of blood flow in these vessels has never been measured nor has a modification of flow been determined when venous return increases by changes in blood volume during hypervolemia or during increased volume input from the posterior lymph hearts. Results Venous return from the posterior region of Bufo marinus was measured under resting conditions and in response to a systemic hypervolemia. Doppler flow probes were positioned on the renal portal and ventral abdominal veins, and flow was recorded as injections of artificial plasma equaling 100% of the animal's plasma volume were administered through the sciatic artery. Resting flow was found to be 5.54 ± 2.03 ml min-1 kg-1 in the paired renal portal veins, and 7.31 ± 0.89 ml min-1 kg-1 in the ventral abdominal vein. While renal portal flow was found to increase by a factor of 2.4 times during the first 10 min of hypervolemia, ventral abdominal flow only increased by a factor of 1.3. Conclusions Our results quantify the contribution to circulation from posterior venous return in the toad Bufo marinus. A preferential movement of excess fluid through the renal portal pathway was also demonstrated, supporting the possibility of water elimination via the renal portal circulation, especially during periods of high water influx into the animals.

  15. Multi-Level Effects of Low Dose Rate Ionizing Radiation on Southern Toad, Anaxyrus [Bufo] terrestris.

    Directory of Open Access Journals (Sweden)

    Karolina Stark

    Full Text Available Despite their potential vulnerability to contaminants from exposure at multiple life stages, amphibians are one of the least studied groups of vertebrates in ecotoxicology, and research on radiation effects in amphibians is scarce. We used multiple endpoints to assess the radiosensitivity of the southern toad (Anaxyrus [Bufo] terrestris during its pre-terrestrial stages of development -embryonic, larval, and metamorphic. Toads were exposed, from several hours after oviposition through metamorphosis (up to 77 days later, to four low dose rates of 137Cs at 0.13, 2.4, 21, and 222 mGy d-1, resulting in total doses up to 15.8 Gy. Radiation treatments did not affect hatching success of embryos, larval survival, or the length of the larval period. The individual family variation in hatching success of embryos was larger than the radiation response. In contrast, newly metamorphosed individuals from the higher dose-rate treatments had higher mass and mass/length body indices, a measure which may relate to higher post-metamorphic survival. The increased mass and index at higher dose rates may indicate that the chronic, low dose rate radiation exposures triggered secondary responses. Additionally, the increases in growth were linked to a decrease in DNA damage (as measured by the Comet Assay in red blood cells at a dose rate of 21 mGy d-1 and a total dose of 1.1 Gy. In conclusion, the complex effects of low dose rates of ionizing radiation may trigger growth and cellular repair mechanisms in amphibian larvae.

  16. Multi-level effects of low dose rate ionizing radiation on southern toad, Anaxyrus [Bufo] terrestris

    International Nuclear Information System (INIS)

    Despite their potential vulnerability to contaminants from exposure at multiple life stages, amphibians are one of the least studied groups of vertebrates in ecotoxicology, and research on radiation effects in amphibians is scarce. We used multiple endpoints to assess the radiosensitivity of the southern toad (Anaxyrus [Bufo] terrestris) during its pre-terrestrial stages of development -embryonic, larval, and metamorphic. Toads were exposed, from several hours after oviposition through metamorphosis (up to 77 days later), to four low dose rates of 137Cs at 0.13, 2.4, 21, and 222 mGy d-1, resulting in total doses up to 15.8 Gy. Radiation treatments did not affect hatching success of embryos, larval survival, or the length of the larval period. The individual family variation in hatching success of embryos was larger than the radiation response. In contrast, newly metamorphosed individuals from the higher dose-rate treatments had higher mass and mass/length body indices, a measure which may relate to higher post-metamorphic survival. The increased mass and index at higher dose rates may indicate that the chronic, low dose rate radiation exposures triggered secondary responses. Additionally, the increases in growth were linked to a decrease in DNA damage (as measured by the Comet Assay) in red blood cells at a dose rate of 21mGy d-1 and a total dose of 1.1 Gy. In conclusion, the complex effects of low dose rates of ionizing radiation may trigger growth and cellular repair mechanisms in amphibian larvae

  17. Mechanisms of ion transport in the mesonephric collecting duct system of Bufo bufo as revealed by microelectrode recordings in isolated perfused tubules

    DEFF Research Database (Denmark)

    Møbjerg, Nadja; Larsen, Erik Hviid; Novak, Ivana

    2002-01-01

    amphibian, Ba2+, Bufo bufo, collecting duct, collecting tubule, K+ conductance, K+ secretion, kidney, mesonephros, ouabain, toad......amphibian, Ba2+, Bufo bufo, collecting duct, collecting tubule, K+ conductance, K+ secretion, kidney, mesonephros, ouabain, toad...

  18. Ultrastructural and Molecular Changes in the Developing Small Intestine of the Toad Bufo regularis

    Directory of Open Access Journals (Sweden)

    S. A. Sakr

    2014-01-01

    Full Text Available The ontogenetic development of the small intestine of the toad Bufo regularis was investigated using twofold approaches, namely, ultrastructural and molecular. The former has been done using transmission electron microscope and utilizing the developmental stages 42, 50, 55, 60, 63, and 66. The most prominent ultrastructural changes were recorded at stage 60 and were more evident at stage 63. These included the appearance of apoptotic bodies/nuclei within the larval epithelium, the presence of macrophages, swollen mitochondria, distorted rough endoplasmic reticulum, chromatin condensation, and irregular nuclear envelop, and the presence of large vacuoles and lysosomes. The molecular investigation involved examining DNA content and fragmentation. The results showed that the DNA content decreased significantly during the metamorphic stages 60 and 63 compared with both larval (50 and 55 and postmetamorphic (66 stages. The metamorphic stages (60 and 63 displayed extensive DNA laddering compared with stages 50, 55, and 66. The percentage of DNA damage was 0.00%, 12.91%, 57.26%, 45.48%, and 4.43% for the developmental stages 50, 55, 60, 63, and 66, respectively. In conclusion, the recorded remodeling of the small intestine represents a model for clarifying the mechanism whereby cell death and proliferation are controlled.

  19. Urea transport across urinary bladder and salt acclimation in toad (Bufo viridis).

    Science.gov (United States)

    Shpun, S; Katz, U

    1990-04-01

    The fluxes of urea across the urinary bladder of the toad Bufo viridis have been studied under conditions of acclimation to tap water or 500 mosM NaCl solution. The [14C]urea fluxes were measured simultaneously with [3H]inulin to test for nonspecific leakage. The fluxes are quite high (Ktrans = 75 x 10(-7) cm/s at 5 mmol/l urea) and are similar in either the mucosal-to-serosal or the opposite direction. "Summer" rates were five to six times higher than the "winter" rates. Antidiuretic hormone (ADH), theophylline, and forskolin increased the fluxes to variable degrees (two to five times), similar in the two acclimation conditions. Phloretin inhibited the urea fluxes by nearly 50%. 1,3-Dimethylurea and thiourea, but not acetamide, competed with the urea fluxes effectively. The fluxes of urea were not affected by the osmotic water flow, although both responded to ADH. It is concluded that urea transport across the urinary bladder of B. viridis is by facilitated diffusion through a specific pathway independent of water flux. The inhibitory effect of the structural analogues on the urea flux was affected by salt acclimation, whereas most other characteristics did not differ significantly at 5 mmol/l external urea under the two conditions of acclimation. PMID:2331031

  20. Genomewide scan for adaptive differentiation along altitudinal gradient in the Andrew's toad Bufo andrewsi.

    Science.gov (United States)

    Guo, Baocheng; Lu, Di; Liao, Wen Bo; Merilä, Juha

    2016-08-01

    Recent studies of humans, dogs and rodents have started to discover the genetic underpinnings of high altitude adaptations, yet amphibians have received little attention in this respect. To identify possible signatures of adaptation to altitude, we performed a genome scan of 15 557 single nucleotide polymorphisms (SNPs) obtained with restriction site-associated DNA sequencing of pooled samples from 11 populations of Andrew's toad (Bufo andrewsi) from the edge of the Tibetan Plateau, spanning an altitudinal gradient from 1690 to 2768 m.a.s.l. We discovered significant geographic differentiation among all sites, with an average FST   = 0.023 across all SNPs. Apart from clear patterns of isolation by distance, we discovered numerous outlier SNPs showing strong associations with variation in altitude (1394 SNPs), average annual temperature (1859 SNPs) or both (1051 SNPs). Levels and patterns of genetic differentiation in these SNPs were consistent with the hypothesis that they have been subject to directional selection and reflect adaptation to altitudinal variation among the study sites. Genes with footprints of selection were significantly enriched in binding and metabolic processes. Several genes potentially related to high altitude adaptation were identified, although the identity and functional significance of most genomic targets of selection remain unknown. In general, the results provide genomic support for results of earlier common garden and low coverage genetic studies that have uncovered substantial adaptive differentiation along altitudinal and latitudinal gradients in amphibians. PMID:27289071

  1. Natural and experimental infection of the lizard Ameiva ameiva with Hemolivia stellata (Adeleina: Haemogregarinidae) of the toad Bufo marinus.

    Science.gov (United States)

    Lainson, R; De Souza, M C; Franco, C M

    2007-12-01

    Developmental stages of a haemogregarine in erythrocytes of the lizard Ameiva ameiva (Teiidae), from Pará State, north Brazil, were shown to be those of Hemolivia by the nature of the parasite's sporogonic cycle in the tick Amblyomma rotondatum. The type species, Hemolivia stellata Petit et al., 1990 was described in the giant toad Bufo marinus and the tick Amblyomma rotondatum, also from Pará State, and in view of the fact that A. ameiva and Bufo marinus share the same habitat and are both commonly infested by A. rotondatum, the possibility that the parasite of A. ameiva is H. stellata had to be considered. Uninfected lizards fed with material from infected ticks taken from B. marinus, and others fed with liver of toads containing tissue-cysts of H. stellata, were shown to subsequently develop typical Hemolivia infections, with all stages of the development similar to those seen in the naturally infected lizards. Conversely, a juvenile, uninfected toad became infected when fed with sporocysts of Hemolivia in a macerated tick that had fed on an infected A. ameiva and pieces of liver containing tissuecysts from the same lizard. The remarkable lack of host specificity shown by H. stellata, in hosts so widely separated as an amphibian and a reptile, is discussed. PMID:18225421

  2. Natural and experimental infection of the lizard Ameiva ameiva with Hemolivia stellata (Adeleina: Haemogregarinidae of the toad Bufo marinus

    Directory of Open Access Journals (Sweden)

    Lainson R.

    2007-12-01

    Full Text Available Developmental stages of a haemogregarine in erythrocytes of the lizard Ameiva ameiva (Teiidae, from Pará State, north Brazil, were shown to be those of Hemolivia by the nature of the parasite’s sporogonic cycle in the tick Amblyomma rotondatum. The type species, Hemolivia stellata Petit et al., 1990 was described in the giant toad Bufo marinus and the tick Amblyomma rotondatum, also from Pará State, and in view of the fact that A. ameiva and Bufo marinus share the same habitat and are both commonly infested by A. rotondatum, the possibility that the parasite of A. ameiva is H. stellata had to be considered. Uninfected lizards fed with material from infected ticks taken from B. marinus, and others fed with liver of toads containing tissuecysts of H. stellata, were shown to subsequently develop typical Hemolivia infections, with all stages of the development similar to those seen in the naturally infected lizards. Conversely, a juvenile, uninfected toad became infected when fed with sporocysts of Hemolivia in a macerated tick that had fed on an infected A. ameiva and pieces of liver containing tissue-cysts from the same lizard. The remarkable lack of host specificity shown by H. stellata, in hosts so widely separated as an amphibian and a reptile, is discussed.

  3. Post-breeding habitat use by adult Boreal Toads (Bufo boreas) after wildfire in Glacier National Park, USA

    Science.gov (United States)

    Guscio, C.G.; Hossack, B.R.; Eby, L.A.; Corn, P.S.

    2008-01-01

    Effects of wildfire on amphibians are complex, and some species may benefit from the severe disturbance of stand-replacing fire. Boreal Toads (Bufo boreas boreas) in Glacier National Park, Montana, USA increased in occurrence after fires in 2001 and 2003. We used radio telemetry to track adult B. boreas in a mosaic of terrestrial habitats with different burn severities to better understand factors related to the post-fire pulse in breeding activity. Toads used severely burned habitats more than expected and partially burned habitats less than expected. No toads were relocated in unburned habitat, but little of the study area was unburned and the expected number of observations in unburned habitat was < 3. High vagility of B. boreas and preference for open habitats may predispose this species to exploit recently disturbed landscapes. The long-term consequences of fire suppression likely have had different effects in different parts of the range of B. boreas. More information is needed, particularly in the northern Rocky Mountains, where toads are more likely to occupy habitats that have diverged from historic fire return intervals. Copyright ?? 2008. C. Gregory Guscio. All rights reserved.

  4. Diet of southern toads (Bufo terrestris) in loblolly pine (Pinus taeda) stands subject to coarse woody debris manipulations.

    Energy Technology Data Exchange (ETDEWEB)

    Moseley, Kurtis R.; Steven B. Castleberry; James L. Hanula; Mark Ford.

    2005-04-01

    ABSTRACT In the southeastern United States, coarse woody debris (CWD) typically harbors high densities of invertebrates. However, its importance as a foraging substrate for southeastern amphibians is relatively unknown. We examined effects of CWD manipulations on diet composition of southern toads (Bufo terrestris) in upland loblolly pine (Pinus taeda) stands in the Coastal Plain of South Carolina. Twelve 9.3-ha plots were assigned one of the following treatments: removal- all CWD _10 cm in diameter and _60 cm long removed; downed- five-fold increase in volume of down CWD; and unmanipulated control stands. We collected southern toads _4 cm snout-vent length (SVL) during 14 d sampling periods in June and October 2002, June 2003 and during a 28 d sampling period in April 2003. We collected 80, 36 and 35 southern toads in control, downed and removal treatments, respectively. We found no difference in relative abundance or frequency of invertebrate groups consumed among treatments (P.0.05). Average body weight (g), SVL (cm) and stomach content weight (g wet) of individuals also were similar among treatments (P . 0.05). The role of CWD as a foraging substrate for southern toads in loblolly pine stands of the southeastern Coastal Plain may be negligible, at least in the early stages of decay.

  5. Determining the effects of cattle grazing treatments on Yosemite toads (Anaxyrus [=Bufo] canorus in montane meadows.

    Directory of Open Access Journals (Sweden)

    Susan K McIlroy

    Full Text Available Amphibians are experiencing a precipitous global decline, and population stability on public lands with multiple uses is a key concern for managers. In the Sierra Nevada Mountains (California, USA, managers have specifically identified livestock grazing as an activity that may negatively affect Yosemite toads due to the potential overlap of grazing with toad habitat. Grazing exclusion from Yosemite toad breeding and rearing areas and/or entire meadows have been proposed as possible management actions to alleviate the possible impact of cattle on this species. The primary objective of this study was to determine if different fencing treatments affect Yosemite toad populations. We specifically examined the effect of three fencing treatments on Yosemite toad breeding pool occupancy, tadpoles, and young of the year (YOY. Our hypothesis was that over the course of treatment implementation (2006 through 2010, Yosemite toad breeding pool occupancy and early life stage densities would increase within two fencing treatments relative to actively grazed meadows due to beneficial changes to habitat quality in the absence of grazing. Our results did not support our hypothesis, and showed no benefit to Yosemite toad presence or early life stages in fenced or partially fenced meadows compared to standard USDA Forest Service grazing levels. We found substantial Yosemite toad variation by both meadow and year. This variation was influenced by meadow wetness, with water table depth significant in both the tadpole and YOY models.

  6. Relation between chloride exchange diffusion and a conductive chloride pathway across the isolated skin of the toad (Bufo bufo)

    DEFF Research Database (Denmark)

    Kristensen, P; Larsen, Erik Hviid

    1978-01-01

    Substitution of chloride in the outside bathing medium of the toad skin with bromide, iodide, nitrate and sulphate leads to a reduction in the apparent exchange diffusion of chloride across this tissue, and also to a reduction of the chloride current recorded during hyperpolarization. A series...... of inhibitors (thiocyanate, furosemide, phloretin, and acetazolamide) also affects chloride exchange diffusion, hyperpolarization current as well as chloride influx during hyperpolarization. Although in some cases, effects on the short circuit current were also observed none of the effects on chloride transport....... On the basis of these findings, and the results reported in the previous paper (Hviid Larsen and Kristensen 1977) it is considered probable that the membrane molecules responsible to chloride exchange diffusion under short circuit conditions, are rearranged under the influence of a hyperpolarizing clamping...

  7. Spatial and temporal ecology of oak toads (Bufo quercicus) on a Florida landscape.

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, Cathryn, H.; Tanner, George, W.

    2005-12-01

    ABSTRACT: We used data from 10 years of continuous, concurrent monitoring of oak toads at eight isolated, ephemeral ponds in Florida longleaf pine-wiregrass uplands to address: (1) did weather variables affect movement patterns of oak toads?; (2) did pond hydrology and the condition of surrounding uplands affect pond selection by adults or juvenile recruitment?; (3) were population trends evident?; and (4) did a classical metapopulation model best represent their population ecology? Of 4076 oak toads captured, 92.2% were adults. Substantial (n _ 30 exiting juveniles) recruitment occurred only three times (once each at three ponds during two years). Males outnumbered females (average for all years 2.3:1). Most captures occurred during May–September. Adult captures during June–August increased with heavier rainfall but were not influenced by the durations of preceding dry periods. Movement patterns of metamorphs suggested that oak toads emigrated when moisture conditions become favorable. Pond use by adults was correlated with maximum change in pond depth (May–September). Juvenile recruitment was negatively correlated with minimum pond depth and the number of weeks since a pond was last dry, and positively correlated with the maximum number of weeks a pond held water continuously. The number of breeding adults and juvenile recruitment were highest at ponds within the hardwood-invaded upland matrix. The direction of most immigrations and emigrations was nonrandom, but movement occurred from all directions, and the mean direction of pond entry and exit did not always correspond. A total of 21.1% of individuals was recaptured; 13.3% of first captures were recaptured during the same year, and 7.7% during a subsequent year. Only 1.9% of captured oak toads moved among ponds, mostly within a distance of 132 m. We did not detect adult population trends over the 10- yr studied. Presence or absence at ponds in any given year was a poor indicator of overall use. We saw

  8. New Karyological and Morphometric Data on Poorly Known Bufo surdus and Bufo luristanicus in Comparison with Data of Diploid Green Toads of the Bufo viridis Complex from South of Iran

    Institute of Scientific and Technical Information of China (English)

    Fatemeh FAKHARZAEH; Jamshid DARVISH; Haji Gholi KAMI; Fereshteh GHASEMZADEH; Eskandar RASTEGAR-POUYANI

    2014-01-01

    Previous studies on the Bufo viridis complex, which is distributed broadly across Iran, are incomplete and restricted to a few regions or a few samples. In this paper a new detailed study on the B. viridis complex in southern of Iran (from West to East) is presented. The analysis of 18 morphometric characters with univariate and multivariate methods reveals significant differences between three members of the B. viridis complex namely B. variabilis, B. luristanicus, and B. surdus distributed in southern part of Iran. Our result help to resolve an old taxonomic problem about B. surdus subgroup (taxa closely related to B. surdus) conifrming that B. luristanicus and B. surdus are distinct species. Moreover, for the ifrst time we report and describe karyotype details of B. luristanicus and B. surdus which conifrmed that they are diploid. Karyological studies demonstrate that all toads from three mentioned species have 2n=22 chromosomes. These chromosomes are arranged into two groups. First group has six large chromosomes and the second group is composed of five small chromosomes. These chromosomes are metacentric or submetacentric. The number of submetacentric chromosomes is different in three mentioned species of B. viridis complex. Neither sexual heteromorphism, nor secondary constriction was observed in any pairs of chromosomes.

  9. A contribution to the knowledge of the trophic spectrum of the Common toad (Bufo bufo L., 1758 (Amphibia: Anura from Bulgaria

    Directory of Open Access Journals (Sweden)

    Petar Boyadzhiev

    2009-07-01

    Full Text Available During our study we identified 500 prey items in 20 prey categories in the trophic spectrum of Bufo bufo with average number of prey items per stomach 25.00. The most important prey taxon is Formicidae (70.20%, followed by Coleoptera (especially Carabidae – 11.40%, as well as non-insect invertebrates (Isopoda, Gastropoda, Arachnida which also play significant role. The estimated trophic niche breadth is low – 1.96.

  10. The influence of ambient salinity and temperature on lipid metabolism in toad (Bufo bufo) skin. Is phosphatidylethanolamine an endogenous regulator of ion channels?

    DEFF Research Database (Denmark)

    Hansen, H.J.M.; Olsen, Allan Gylling; Willumsen, Niels J.

    1994-01-01

    ) were found in vivo, when toads adapted to Ringer solution were transferred to tap water containing tracer amounts of (32P) phosphate and (14C) acetate. PE could play a role in the formation of a "hydrophilic" environment and thereby, e.g. stabilise the integral membrane proteins that regulate...

  11. Isolation and sequencing of doublesex/male abnormal 3 (DM related transcription factor (Dmrt genes from the Asian toad Bufo gargarizans (Cantor, 1842

    Directory of Open Access Journals (Sweden)

    Wen Chen

    2007-01-01

    Full Text Available The doublesex/male abnormal 3 (dsx/mab-3 or DM domain gene family involved in sexual development encodes putative transcription factors including a DNA-binding homology motif, the DM domain. We used highly degenerate primers to clone and sequence seven distinct DM related transcription factor (Dmrt genes from the Asian toad (Bufo gargarizans Cantor, 1842. A database search for the cloned sequences revealed the following percentage identity with the homologous Dmrt genes of the human: BgDmrt1 = 97%, BgDmrt2 = 97%, three isoforms of BgDmrt3 (BgDmrt3a = 93%, BgDmrt3b = 95%, BgDmrt3c = 100% and two isoforms of BgDmrt5 (BgDmrt5 = 97%, BgDmrt5 = 91%. Based on DM domain amino acid sequence similarities we constructed a phylogenetic tree which grouped vertebrate and invertebrate Dmrt genes into seven distinct subfamilies. The DM domains of both human and the newly-discovered Bufo gargarizans genes contained two conserved zinc-chelating sites (CCHC and HCCC, except BgDmrt3b, which contained the CCRC and HCCC sites.

  12. Exposure of toad embryos and larvae to pesticides. Use of nuclear technique to determine their effect on the reproduction, survival and potential risk to Bufo arenarum populations

    International Nuclear Information System (INIS)

    Application of pesticides is currently the most common method used to control agricultural pests. However, undesired effects on non-target organisms and pollution of the soil, air and water are frequent consequences. Amphibians are good bioindicators of the presence of contaminants in the environment, because they are semi-aquatic animals located at the top of the food chain. In many parts of the world, amphibian populations are declining, and many reasons have been suggested for these losses. Although a link between widespread decline and pesticide residues has yet to be established, it is suspected that contamination of their breeding sites with pesticide residues has had a deleterious effect on the reproduction and development of amphibians. Recent experiments with a widely distributed toad, Bufo arenarum Hensel, in South America, particularly in Argentina, indicate that a variety of insecticides affects the fertilization process through the activation of an enzyme that degrades the source of second messengers and is involved in transducing the sperm signal to the oocyte. This harmful effect is not restricted to the fertilization process, since embryonic and larval development are also affected, producing severe morphological and behavioural abnormalities in embryos. Embryonic and larval development influence the timing of metamorphosis, the susceptibility to predation, survival in the terrestrial environment, and even the success of future reproduction, these being the most sensitive period of a toad's life. Evaluation of the pesticides in our region showed their presence in many of the potential breeding sites, confirming that they may influence the survival of toad populations. (author). 18 refs, 1 fig., 1 tab

  13. A Single Transcriptome of a Green Toad (Bufo viridis) Yields Candidate Genes for Sex Determination and -Differentiation and Non-Anonymous Population Genetic Markers.

    Science.gov (United States)

    Gerchen, Jörn F; Reichert, Samuel J; Röhr, Johannes T; Dieterich, Christoph; Kloas, Werner; Stöck, Matthias

    2016-01-01

    Large genome size, including immense repetitive and non-coding fractions, still present challenges for capacity, bioinformatics and thus affordability of whole genome sequencing in most amphibians. Here, we test the performance of a single transcriptome to understand whether it can provide a cost-efficient resource for species with large unknown genomes. Using RNA from six different tissues from a single Palearctic green toad (Bufo viridis) specimen and Hiseq2000, we obtained 22,5 Mio reads and publish >100,000 unigene sequences. To evaluate efficacy and quality, we first use this data to identify green toad specific candidate genes, known from other vertebrates for their role in sex determination and differentiation. Of a list of 37 genes, the transcriptome yielded 32 (87%), many of which providing the first such data for this non-model anuran species. However, for many of these genes, only fragments could be retrieved. In order to allow also applications to population genetics, we further used the transcriptome for the targeted development of 21 non-anonymous microsatellites and tested them in genetic families and backcrosses. Eleven markers were specifically developed to be located on the B. viridis sex chromosomes; for eight markers we can indeed demonstrate sex-specific transmission in genetic families. Depending on phylogenetic distance, several markers, which are sex-linked in green toads, show high cross-amplification success across the anuran phylogeny, involving nine systematic anuran families. Our data support the view that single transcriptome sequencing (based on multiple tissues) provides a reliable genomic resource and cost-efficient method for non-model amphibian species with large genome size and, despite limitations, should be considered as long as genome sequencing remains unaffordable for most species. PMID:27232626

  14. Strong reproductive barriers in a narrow hybrid zone of West-Mediterranean green toads (Bufo viridis subgroup with Plio-Pleistocene divergence

    Directory of Open Access Journals (Sweden)

    Perrin Nicolas

    2010-07-01

    Full Text Available Abstract Background One key question in evolutionary biology deals with the mode and rate at which reproductive isolation accumulates during allopatric speciation. Little is known about secondary contacts of recently diverged anuran species. Here we conduct a multi-locus field study to investigate a contact zone between two lineages of green toads with an estimated divergence time of 2.7 My, and report results from preliminary experimental crosses. Results The Sicilian endemic Bufo siculus and the Italian mainland-origin B. balearicus form a narrow hybrid zone east of Mt. Etna. Despite bidirectional mtDNA introgression over a ca. 40 km North-South cline, no F1 hybrids could be found, and nuclear genomes display almost no admixture. Populations from each side of the contact zone showed depressed genetic diversity and very strong differentiation (FST = 0.52. Preliminary experimental crosses point to a slightly reduced fitness in F1 hybrids, a strong hybrid breakdown in backcrossed offspring (F1 x parental, with very few reaching metamorphosis and a complete and early mortality in F2 (F1 x F1. Conclusion Genetic patterns at the contact zone are molded by drift and selection. Local effective sizes are reduced by the geography and history of the contact zone, B. balearicus populations being at the front wave of a recent expansion (late Pleistocene. Selection against hybrids likely results from intrinsic genomic causes (disruption of coadapted sets of genes in backcrosses and F2-hybrids, possibly reinforced by local adaptation (the ranges of the two taxa roughly coincide with the borders of semiarid and arid climates. The absence of F1 in the field might be due to premating isolation mechanisms. Our results, show that these lineages have evolved almost complete reproductive isolation after some 2.7 My of divergence, contrasting sharply with evidence from laboratory experiments that some anuran species may still produce viable F1 offspring after > 20

  15. Determination of pesticide aerial drift and associated effects to the endangered Wyoming toad (Bufo baxteri) at Mortenson and Hutton National Wildlife Refuges and potential reintroduction sites

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The endangered Wyoming toad is confined to Mortenson National Wildlife Refuge (NWR) in southeast Wyoming. Reasons for the decline of the toad are unknown, but it is...

  16. Agregace jako antipredační strategie u pulců ropuchy obecné (\\kur{Bufo bufo}).

    OpenAIRE

    BODNÁR, Tomáš

    2007-01-01

    Tadpoles of many anuran species use a huge number of behavioral modifications to avoid predators. Reduced activity in presence of predators is favorite strategy for common toad tadpoles (Bufo bufo). Responses against predator cues by tadpoles of Bufo bufo in the presence of another cue of larger tadpole aggregation were tested in this study. We observed that these tadpoles responded differently to predator chemical cues than tadpoles in a small group.

  17. 花背蟾蜍皮肤结构及其抗氧化和免疫功能的研究%Microstructure of toad (Bufo raddei) andits antioxidant and immune function

    Institute of Scientific and Technical Information of China (English)

    高凤娟; 李丕鹏; 陆宇燕

    2015-01-01

    In order to understand the skin structure and function of the toad (Bufo raddei),the conventional paraffin section technique and ELISA were adopted to observe the microstructural characteristics of its dorsal skin,ventral skin and skin glands;and determine the contents of SOD,CAT,MDA,TLR4 andβD-1 of the dorsal skin and ventral skin, respectively.The results show that the toad skin structures are similar to other amphibians.That is the ventral cuticle thicker than the dorsal,the dorsal epidermis and dermis thicker than the ventral,granular glands mainly in the dorsal skin,and mucous glands in the ventral skin.SOD and TLR4 examined in the ventral skin are higher than in the dorsal skin,CAT containing in the dorsal skin is higher than in the ventral skin,but MDA andβD-1 are similar in these two areas.In conclusion,the structures and related protein levels of the toad skin closely adapt to the living environment,and have the antioxidant capacities and natural immune functions.%为了深入了解花背蟾蜍(Bufo raddei Strauch)皮肤显微结构及其相关功能,利用石蜡切片及酶联免疫吸附反应技术,观察了花背蟾蜍背腹侧皮肤及其皮肤腺的显微结构特点,分别测定了背、腹侧皮肤中 SOD、CAT、MDA、TLR4和βD-1含量。结果:花背蟾蜍皮肤结构与其他两栖类皮肤结构基本相同,其角质层腹侧较背侧厚,表皮和真皮背侧较腹侧厚;颗粒腺主要存在于背侧,而黏液腺主要存在于腹侧。SOD和TLR4含量腹侧皮肤高于背侧皮肤;CAT含量背侧皮肤较腹侧高;MDA和βD-1含量在背腹皮肤中相近。结论:花背蟾蜍皮肤结构和相关蛋白水平能够较好的适应其生境,并具有一定的抗氧化能力和天然免疫功能。

  18. Microstructure of toad (Bufo raddei) andits antioxidant and immune function%花背蟾蜍皮肤结构及其抗氧化和免疫功能的研究

    Institute of Scientific and Technical Information of China (English)

    高凤娟; 李丕鹏; 陆宇燕

    2015-01-01

    In order to understand the skin structure and function of the toad (Bufo raddei),the conventional paraffin section technique and ELISA were adopted to observe the microstructural characteristics of its dorsal skin,ventral skin and skin glands;and determine the contents of SOD,CAT,MDA,TLR4 andβD-1 of the dorsal skin and ventral skin, respectively.The results show that the toad skin structures are similar to other amphibians.That is the ventral cuticle thicker than the dorsal,the dorsal epidermis and dermis thicker than the ventral,granular glands mainly in the dorsal skin,and mucous glands in the ventral skin.SOD and TLR4 examined in the ventral skin are higher than in the dorsal skin,CAT containing in the dorsal skin is higher than in the ventral skin,but MDA andβD-1 are similar in these two areas.In conclusion,the structures and related protein levels of the toad skin closely adapt to the living environment,and have the antioxidant capacities and natural immune functions.%为了深入了解花背蟾蜍(Bufo raddei Strauch)皮肤显微结构及其相关功能,利用石蜡切片及酶联免疫吸附反应技术,观察了花背蟾蜍背腹侧皮肤及其皮肤腺的显微结构特点,分别测定了背、腹侧皮肤中 SOD、CAT、MDA、TLR4和βD-1含量。结果:花背蟾蜍皮肤结构与其他两栖类皮肤结构基本相同,其角质层腹侧较背侧厚,表皮和真皮背侧较腹侧厚;颗粒腺主要存在于背侧,而黏液腺主要存在于腹侧。SOD和TLR4含量腹侧皮肤高于背侧皮肤;CAT含量背侧皮肤较腹侧高;MDA和βD-1含量在背腹皮肤中相近。结论:花背蟾蜍皮肤结构和相关蛋白水平能够较好的适应其生境,并具有一定的抗氧化能力和天然免疫功能。

  19. Embryotoxicity of lead on Bufo arenarum

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Coll, C.S.; Herkovits, J.; Salibian, A.

    1988-08-01

    Lead, one of the oldest and more widely distributed pollutants, produces serious toxicological effects. From an ecotoxicological point of view, amphibians are useful as indicators of environmental contamination because they are sensitive to a great variety of toxic agents. Considering that Bufo arenarum is one of the most widely distributed toads in South America, in the present work the authors study the LC50 and teratogenical effects of lead on Bufo arenarum embryos obtained from different couples of parents exposing them from the 2-cell stage onwards. A differential susceptibility to this heavy metal in embryos obtained from five different couples of parents is described.

  20. Toad envenoming in dogs: effects and treatment

    OpenAIRE

    M. SAKATE; P. C. Lucas de Oliveira

    2000-01-01

    Toads (order: Anura; family: Bufonidae; genus: Bufo) are distributed throughout the world, but more species are found in areas of tropical and humid temperate climates. Although toads do not have a venom inoculation system, they are venomous animals because the glands covering the whole surface of their bodies secrete a milk-like venom of which composition is not yet completely known. Some of these glands are the bilateral glands located in post-orbital position. These glands, which are somew...

  1. EFFECTS OF AMINO ACIDS ON THE MEMBRANE POTENTIAL OF TOAD OOCYTES AND THE MECHANISMS INVOLVED

    Institute of Scientific and Technical Information of China (English)

    WANGYu-Feng; CHENGJiun; CHENGZhi-Ping

    1989-01-01

    The etTects of 23 amino acids on the membrane potential of toad ( Bufo bufo gargarizans ) oocytes and the mechanisms involved were investigated in vitro by means of microelectrode. At a concentration of I mmol/L-alanine, leucine and lyaine induced signfiant depolarization, and tryptophan provoked a marked hyperpolarization during

  2. Effects of salinity stress on Bufo balearicus and Bufo bufo tadpoles: Tolerance, morphological gill alterations and Na+/K+-ATPase localization

    International Nuclear Information System (INIS)

    Freshwater habitats are globally threatened by human-induced secondary salinization. Amphibians are generally poorly adapted to survive in saline environments. We experimentally investigated the effects of chronic exposure to various salinities (5%, 10%, 15%, 20%, 25%, 30% and 35% seawater, SW) on survival, larval growth and metamorphosis of tadpoles from two amphibian populations belonging to two species: the green toad Bufo balearicus and the common toad Bufo bufo. In addition, gill morphology of tadpoles of both species after acute exposure to hypertonic conditions (20%, 25%, and 30% SW) was examined by light and electron microscopy. Tadpoles experienced 100% mortality above 20% SW in B. balearicus while above 15% SW in B. bufo. We detected also sublethal effects of salinity stress on growth and metamorphosis. B. bufo cannot withstand chronic exposure to salinity above 5% SW, tadpoles grew slower and were significantly smaller than those in control at metamorphosis. B. balearicus tolerated salinity up to 20% SW without apparent effects during larval development, but starting from 15% SW tadpoles metamorphosed later and at a smaller size compared with control. We also revealed a negative relation between increasing salt concentration and gill integrity. The main modifications were increased mucous secretion, detachment of external layer, alteration of epithelial surface, degeneration phenomena, appearance of residual bodies, and macrophage immigration. These morphological alterations of gill epithelium can interfere with respiratory function and both osmotic and acid-base regulation. Significant variations in branchial Na+/K+-ATPase activity were also observed between two species; moreover an increase in enzyme activity was evident in response to SW exposure. Epithelial responses to increasing salt concentration were different in the populations belonging to two species: the intensity of histological and ultrastructural pathology in B. bufo was greater and we

  3. DIET OF THE SOUTHERN TOAD FROM THE SOUTHERN EVERGLADES

    Science.gov (United States)

    We examined the diet of a February-May sample of the southern toad (Bufo Terrestris) from the Everglades National Park. Above the familial level, 13 taxa were consumed, but ants (Hymenoptera) and beetles (Coleoptera) were consumed most by, and in the greatest number of s...

  4. Diet composition of the invasive cane toad (Chaunus marinus) on Rota, Northern Mariana Islands

    Science.gov (United States)

    Reed, R.N.; Bakkegard, K.A.; Desy, G.E.; Plentovich, S.M.

    2007-01-01

    The cane or marine toad (Chaunus marinus, formerly Bufo marinus) was introduced to the Northern Mariana Islands starting in the 1930s. The effects of this exotic predator on native vertebrates (especially lizards) are largely unknown. We analysed the stomach contents of 336 cane toads collected from the island of Rota, with the goal of estimating the level of toad predation on native vertebrates. Beetles, ants, millipedes, and grasshoppers/crickets comprised the majority of prey classes consumed by toads. The introduced Brahminy blindsnake (Ramphotyphlops braminus; N = 6) and conspecific cane toads (N = 4) were the vertebrates most commonly found in toad stomachs. Skinks (Emoia; N = 2) were the only native vertebrates represented in our sample. The small numbers of nocturnal terrestrial vertebrates native to Rota likely translates to relatively low rates of predation by cane toads on native vertebrates.

  5. Concentration dependence of halide fluxes and selectivity of the anion pathway in toad skin

    DEFF Research Database (Denmark)

    Harck, A F; Larsen, Erik Hviid

    1986-01-01

    The isolated toad (Bufo bufo) skin was mounted under voltage-clamp conditions in a chamber shown to cause no significant edge damage. The serosal side of the skin was bathed with NaCl-Ringer's, and the passive voltage-sensitive anion conductance studied in its fully voltage activated state, V = -...... of the red cell membrane accounts for our findings, and for an inwardly directed active Cl- flux in terms of Cl-/HCO3- exchange....

  6. Trophic ecology and microhabitat utilization by the Bufo gargarizans, Rana guentheri, and Rana limnocharis in southwestern China

    OpenAIRE

    Tonglei Yu; Yanshu Guo

    2012-01-01

    We studied the trophic ecology and microhabitat use of the Asiatic toad, Bufo gargarizans Cantor, 1842; Guentheri frog, Rana guentheri (Boulenger, 1882); and the Ricefield frog, Rana limnocharis (Boie, 1834). These three species are common around Nanchong City, in southwestern China, where they live in the same habitat before hibernation. The main objective of this study was to analyze the diets and patterns of coexistence relative to the microhabitat of each species. In the Asiatic toad, bas...

  7. Differences and Similarities among Parotoid Macrogland Secretions in South American Toads: A Preliminary Biochemical Delineation

    OpenAIRE

    Juliana Mozer Sciani; Cláudia Blanes Angeli; Antoniazzi, Marta M.; Carlos Jared; Daniel Carvalho Pimenta

    2013-01-01

    Amphibians are known by cutaneous glands, spread over the skin, containing toxins (proteins, peptides, biogenic amines, steroidal bufadienolides, and alkaloids) used as chemical defense against predators and microbial infection. Toads are characterized by the presence of parotoid macroglands. The common toads have lately been divided into two genera: Bufo (Europe, Asia, and Africa) and Rhinella (South America). Basal Rhaebo genus is exclusively of Central America and Amazon region. Although R...

  8. Effects of salinity stress on Bufo balearicus and Bufo bufo tadpoles: Tolerance, morphological gill alterations and Na{sup +}/K{sup +}-ATPase localization

    Energy Technology Data Exchange (ETDEWEB)

    Bernabò, Ilaria; Bonacci, Antonella; Coscarelli, Francesca [Department of Ecology, University of Calabria, Via P. Bucci, 87036 Rende (Cosenza) (Italy); Tripepi, Manuela [University of Pennsylvania, Department of Biology, 201 Leidy Laboratories, Philadelphia, PA 19104 (United States); Brunelli, Elvira, E-mail: brunelli@unical.it [Department of Ecology, University of Calabria, Via P. Bucci, 87036 Rende (Cosenza) (Italy)

    2013-05-15

    Freshwater habitats are globally threatened by human-induced secondary salinization. Amphibians are generally poorly adapted to survive in saline environments. We experimentally investigated the effects of chronic exposure to various salinities (5%, 10%, 15%, 20%, 25%, 30% and 35% seawater, SW) on survival, larval growth and metamorphosis of tadpoles from two amphibian populations belonging to two species: the green toad Bufo balearicus and the common toad Bufo bufo. In addition, gill morphology of tadpoles of both species after acute exposure to hypertonic conditions (20%, 25%, and 30% SW) was examined by light and electron microscopy. Tadpoles experienced 100% mortality above 20% SW in B. balearicus while above 15% SW in B. bufo. We detected also sublethal effects of salinity stress on growth and metamorphosis. B. bufo cannot withstand chronic exposure to salinity above 5% SW, tadpoles grew slower and were significantly smaller than those in control at metamorphosis. B. balearicus tolerated salinity up to 20% SW without apparent effects during larval development, but starting from 15% SW tadpoles metamorphosed later and at a smaller size compared with control. We also revealed a negative relation between increasing salt concentration and gill integrity. The main modifications were increased mucous secretion, detachment of external layer, alteration of epithelial surface, degeneration phenomena, appearance of residual bodies, and macrophage immigration. These morphological alterations of gill epithelium can interfere with respiratory function and both osmotic and acid-base regulation. Significant variations in branchial Na{sup +}/K{sup +}-ATPase activity were also observed between two species; moreover an increase in enzyme activity was evident in response to SW exposure. Epithelial responses to increasing salt concentration were different in the populations belonging to two species: the intensity of histological and ultrastructural pathology in B. bufo was

  9. Spontaneous firing in olfactory bulb neurons of Bufo bufo gargarizans in and after hibernation

    Institute of Scientific and Technical Information of China (English)

    Chuancheng Liang; Shaokang Bian; Xia Peng; Liwen Wang

    2011-01-01

    Microelectrode technique was used to record the spontaneous electrical activities of the neurons in olfactory bulb of the Bufo bufo gargarizans, both in hibernation and after hibernation. This study investigated the electrophysiological characteristics of amphibian olfactory bulb in the period of hibernation and after hibernation and its effects on the start of hibernation and spontaneous awakening. The research showed four forms of spontaneous firings: single spontaneous firing, burst spontaneous firing, irregular spontaneous firing and consecutive single spontaneous firing. The single spontaneous firing includes slow depolarized spontaneous firing and fast depolarized spontaneous firing, and the slow depolarized spontaneous firing occurs only during the hibernation period. In hibernation, the low amplitude and low frequency firing with a longer duration may be relevant to maintaining the tonicity of the central nervous system in toads that are in hibernation, and this kind of firing may also provide an excited basis for their arousal from hibernation. After hibernation, the amplitude and frequency of firing increase, but the firing duration gets shorter. This form of short-term firing, which may be a phenomenon of sensory neurons fast adapting, is one of the neuronal mechanisms for the arousal of hibernating animals.

  10. Estimation of temporary emigration in male toads

    Science.gov (United States)

    Muths, E.; Scherer, R. D.; Corn, P.S.; Lambert, B.A.

    2006-01-01

    Male boreal toads (Bufo boreas) are thought to return to the breeding site every year but, if absent in a particular year, will be more likely to return the following year. Using Pollock's robust design we estimated temporary emigration (the probability a male toad is absent from a breeding site in a given year) at three locations in Colorado, USA: two in Rocky Mountain National Park and one in Chaffee County. We present data that suggest that not all male toads return to the breeding site every year. Our analyses indicate that temporary emigration varies by site and time (for example, from 1992 to 1998, the probability of temporary emigration ranged from 10% to 29% and from 3% to 95% at Lost Lake and Kettle Tarn, respectively). Although the results provide weak evidence that males are more likely to return after a year's hiatus, a general pattern of state-dependent temporary emigration was not supported. We also hypothesized relationships between temporary emigration and a number of weather variables. While some competitive models included weather covariates, imprecise and variable estimates of the effects of these covariates precluded fully defining their impact on temporary emigration. ?? 2006 by the Ecological Society of America.

  11. Mapping the Relative Probability of Common Toad Occurrence in Terrestrial Lowland Farm Habitat in the United Kingdom.

    Directory of Open Access Journals (Sweden)

    Rosie D Salazar

    Full Text Available The common toad (Bufo bufo is of increasing conservation concern in the United Kingdom (UK due to dramatic population declines occurring in the past century. Many of these population declines coincided with reductions in both terrestrial and aquatic habitat availability and quality and have been primarily attributed to the effect of agricultural land conversion (of natural and semi-natural habitats to arable and pasture fields and pond drainage. However, there is little evidence available to link habitat availability with common toad population declines, especially when examined at a broad landscape scale. Assessing such patterns of population declines at the landscape scale, for instance, require an understanding of how this species uses terrestrial habitat.We intensively studied the terrestrial resource selection of a large population of common toads in Oxfordshire, England, UK. Adult common toads were fitted with passive integrated transponder (PIT tags to allow detection in the terrestrial environment using a portable PIT antenna once toads left the pond and before going into hibernation (April/May-October 2012 and 2013. We developed a population-level resource selection function (RSF to assess the relative probability of toad occurrence in the terrestrial environment by collecting location data for 90 recaptured toads.The predicted relative probability of toad occurrence for this population was greatest in wooded habitat near to water bodies; relative probability of occurrence declined dramatically > 50 m from these habitats. Toads also tended to select habitat near to their breeding pond and toad occurrence was negatively related to urban environments.

  12. Properties of a conductive cellular chloride pathway in the skin of the toad (Bufo bufo)

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Kristensen, P

    1978-01-01

    of the steady-state conductance and the steady-state chloride current reveal that the chloride pathway has maximum conductance for V approximately -80 mV (outside of the skin being negative) and approaches a non-conducting safe for V greater than 0 mV. This strong outward going rectification is a steady......-compartment model indicate that the strong steady-state chloride current rectification cannot be obtained if only the intracellular chloride concentration and the membrane potentials are allowed to vary ("Goldman-rectification"). It is suggested, therefore, that the premeability of the chloride pathway varies...

  13. Effects of amphibian chytrid fungus on individual survival probability in wild boreal toads

    Science.gov (United States)

    Pilliod, D.S.; Muths, E.; Scherer, R. D.; Bartelt, P.E.; Corn, P.S.; Hossack, B.R.; Lambert, B.A.; Mccaffery, R.; Gaughan, C.

    2010-01-01

    Chytridiomycosis is linked to the worldwide decline of amphibians, yet little is known about the demographic effects of the disease. We collected capture-recapture data on three populations of boreal toads (Bufo boreas [Bufo = Anaxyrus]) in the Rocky Mountains (U.S.A.). Two of the populations were infected with chytridiomycosis and one was not. We examined the effect of the presence of amphibian chytrid fungus (Batrachochytrium dendrobatidis [Bd]; the agent of chytridiomycosis) on survival probability and population growth rate. Toads that were infected with Bd had lower average annual survival probability than uninfected individuals at sites where Bd was detected, which suggests chytridiomycosis may reduce survival by 31-42% in wild boreal toads. Toads that were negative for Bd at infected sites had survival probabilities comparable to toads at the uninfected site. Evidence that environmental covariates (particularly cold temperatures during the breeding season) influenced toad survival was weak. The number of individuals in diseased populations declined by 5-7%/year over the 6 years of the study, whereas the uninfected population had comparatively stable population growth. Our data suggest that the presence of Bd in these toad populations is not causing rapid population declines. Rather, chytridiomycosis appears to be functioning as a low-level, chronic disease whereby some infected individuals survive but the overall population effects are still negative. Our results show that some amphibian populations may be coexisting with Bd and highlight the importance of quantitative assessments of survival in diseased animal populations. Journal compilation. ?? 2010 Society for Conservation Biology. No claim to original US government works.

  14. Karyological and flow cytometric evidence of triploid specimens in Bufo viridis (Amphibia Anura

    Directory of Open Access Journals (Sweden)

    D Cavallo

    2010-01-01

    Full Text Available Karyological and flow cytometric (FCM analyses were performed on a group of 14 green toads of the Bufo viridis species from seven Eurasian populations. Both approaches gave concordant results concerning the DNA ploidy level. All the populations examined were represented exclusively by diploid or tetraploid specimens, except one, where triploids were found. Results evidenced an interpopulation variability in DNA content against the same ploidy level, as well as an unusually high number of triploids in a particular reproductive place. The origin of polyploidy and the presence and persistence of a high number of triploids in a particular population are discussed.

  15. Toad Glandular Secretions and Skin Extractions as Anti-Inflammatory and Anticancer Agents

    Directory of Open Access Journals (Sweden)

    Ji Qi

    2014-01-01

    Full Text Available Toad glandular secretions and skin extractions contain many natural agents which may provide a unique resource for novel drug development. The dried secretion from the auricular and skin glands of Chinese toad (Bufo bufo gargarizans is named Chansu, which has been used in Traditional Chinese Medicine (TCM for treating infection and inflammation for hundreds of years. The sterilized hot water extraction of dried toad skin is named Huachansu (Cinobufacini which was developed for treating hepatitis B virus (HBV and several types of cancers. However, the mechanisms of action of Chansu, Huachansu, and their constituents within are not well reported. Existing studies have suggested that their anti-inflammation and anticancer potential were via targeting Nuclear Factor (NF-κB and its signalling pathways which are crucial hallmarks of inflammation and cancer in various experimental models. Here, we review some current studies of Chansu, Huachansu, and their compounds in terms of their use as both anti-inflammatory and anticancer agents. We also explored the potential use of toad glandular secretions and skin extractions as alternate resources for treating human cancers in combinational therapies.

  16. Male size does not correlate with fertilization success in two bufonid toads that show size-assortative mating

    OpenAIRE

    Xiao-Li FAN, Zhi-Hua LIN, Xiang JI

    2013-01-01

    We examined sexual size dimorphism (SSD), mating pattern, fertilization efficiency and female reproductive traits in two bufonid toads (Bufo gargarizans and Duttaphrynus melanostictus) to test the idea that importance of male body size for egg fertilization success depends on the mating pattern. Female-biased SSD was evident only in D. melanostictus. Female B. gargarizans laid fewer larger eggs nearly three months earlier than did female D. melanostictus. Fertilization efficiencies on average...

  17. Temperature, hydric environment, and prior pathogen exposure alter the experimental severity of chytridiomycosis in boreal toads

    Science.gov (United States)

    Murphy, Peter J.; St-Hilaire, Sophie; Corn, Paul Stephen

    2011-01-01

    Prevalence of the pathogen Batrachochytrium dendrobatidis (Bd), implicated in amphibian population declines worldwide, is associated with habitat moisture and temperature, but few studies have varied these factors and measured the response to infection in amphibian hosts. We evaluated how varying humidity, contact with water, and temperature affected the manifestation of chytridiomycosis in boreal toads Anaxyrus (Bufo) boreas boreas and how prior exposure to Bd affects the likelihood of survival after re-exposure, such as may occur seasonally in long-lived species. Humidity did not affect survival or the degree of Bd infection, but a longer time in contact with water increased the likelihood of mortality. After exposure to ~106 Bd zoospores, all toads in continuous contact with water died within 30 d. Moreover, Bd-exposed toads that were disease-free after 64 d under dry conditions, developed lethal chytridiomycosis within 70 d of transfer to wet conditions. Toads in unheated aquaria (mean = 15°C) survived less than 48 d, while those in moderately heated aquaria (mean = 18°C) survived 115 d post-exposure and exhibited behavioral fever, selecting warmer sites across a temperature gradient. We also found benefits of prior Bd infection: previously exposed toads survived 3 times longer than Bd-naïve toads after re-exposure to 106 zoospores (89 vs. 30 d), but only when dry microenvironments were available. This study illustrates how the outcome of Bd infection in boreal toads is environmentally dependent: when continuously wet, high reinfection rates may overwhelm defenses, but periodic drying, moderate warming, and previous infection may allow infected toads to extend their survival.

  18. A contribution to the intraspecific systematics of Bufo bufo (Linnaeus, 1758) (Amphibia)

    NARCIS (Netherlands)

    Lange, de L.

    1973-01-01

    A biometrical analysis of preserved specimens of Bufo bufo, supplemented by a detailed examination of the shape of the skin warts, was performed in order to ascertain the taxonomic status of the form described as B.b.spinosus. Indications of a N.-S. clinal variation in the formation of wart thorns a

  19. Baroreceptor control of heart rate in the awake toad: peripheral autonomic effectors and arterial baroreceptor areas.

    Science.gov (United States)

    Bianchi-da-Silva, L M; Menescal-de-Oliveira, L; Hoffmann, A

    2000-04-12

    Systemic injection of sodium nitroprusside (30 microg/kg, i.v.) in the awake Bufo paracnemis toad induced a fall in arterial blood pressure and tachycardia. This tachycardia, but not the hypotension, was significantly reduced in toads with bilateral electrolytic lesion of the caudal and commissural regions of the solitary tract nucleus and in animals with transection of the spinal cord, 2 mm below the obex. This indicates that the tachycardia is reflex, depends on the integrity of the solitary tract nucleus and is due to descending spinal autonomic activation. Pretreatment with propranolol (4 mg/kg, i.v.) significantly reduced the tachycardia but did not block it completely, showing the importance of beta-adrenoceptors in its genesis. The reflex increase in heart rate induced by nitroprusside was not statistically significant in animals with bilateral section of the laryngeal nerve, whose baroreceptor fibers originate from the pulmocutaneous artery or in animals in which the bilateral section of the laryngeal nerve was performed together with section of the glossopharyngeal nerves, which incorporate fibers originating from the carotid labyrinth. The reduction of the reflex tachycardia was significant in toads with aortic arch denervation alone or combined with section of the laryngeal nerves or in animals with complete denervation of the three baroreceptors areas. These results suggest that the region of the aortic arch, when submitted to unloading, is the most important baroreceptor zone for cardiac compensation in toads.

  20. Haematological changes in Bufo maculatus treated with sublethal concentrations of Cadmium

    Directory of Open Access Journals (Sweden)

    Lawrence Ikechukwu Ezemonye

    2011-12-01

    Full Text Available Adult Bufo maculatus was exposed to sublethal cadmium concentrations of 0.25, 0.50, 1.00 and 2.00 mg/L. The toxicant from which the cadmium concentrations were prepared was cadmium chloride (CdCl2.H2O. There were three replicate tanks per treatment and three individuals per tank including control groups. The hematologic alterations based on the examination of blood indices during the 28 days of exposure showed that total erythrocyte count (TEC, hematocrit (Hct and hemoglobin (Hb concentration decreased (P<0.05 relative to controls. The decline was concentration- dependent as concentration of cadmium increased. The decline in hemoglobin and hematocrit in the experimental organism could be due to a decrease in the synthesis or release of erythrocytes into the circulation or an increase in the rate of erythrocyte destruction inflicted by cadmium toxicity. There was significant (P<0.05 elevation in total leuko- leukocyte count (TLC with increase in the concen- cyte concentration of cadmium. The increase in total leukocyte count observed in this study could be attributed to a stimulation of the immune system in response to tissue damage caused by cadmium toxicity. The study has shown that the exposure of the Bufo maculatus toad to cadmium can inflict alterations in the hematologic indices, which could induce unfavorable physiological changes in the amphibian, which may lead to death. There is, therefore, the need to protect amphibians in order to sustain the biodiversity in the Nigerian Niger Delta ecological zone.

  1. Changes to the generic names of extinct east European species described as Bufo belogoricus Ratnikov, 1993, Bufo planus Ratnikov, 1993 and Bufo albus Ratnikov, 1993

    Directory of Open Access Journals (Sweden)

    Ratnikov, V. Yu

    2013-06-01

    Full Text Available The generic assignment of three fossil forms described as Bufo belogoricus Ratnikov, 1993, Bufo planus Ratnikov, 1993 and Bufo albus Ratnikov, 1993 is discussed. The author justifies why their original generic names should not be changed to Pseudepidalea, as recently proposed, but should be maintained until more convincing evidence is discovered.Se discute la atribución genérica de tres formas fósiles descritas como Bufo belogoricus Ratnikov, 1993, Bufo planus Ratnikov, 1993, y Bufo albus Ratnikov, 1993. El autor justifica las razones por las cuales las adscripciones genéricas originales no deberían cambiarse a Pseudepidalea, como recientemente se ha propuesto, sino mantenerse hasta que se descubra nueva evidencia más convincente.

  2. A novel ubiquitin carboxyl terminal hydrolase is involved in toad oocyte maturation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    p28, a 28kD protein from toad (Bufo bufo gargarizans) oocytes, was identified by using p13suc1-agaroseaffinity chromatography. Sequence homology analysis of the full-length cDNA of p28 (Gene Bank accessionnumber: AF 314091) indicated that it encodes a protein containing 224 amino-acids with about 55% iden-tities and more than 70% positives to human, rat or mouse UCH-L1, and contains homological functionaldomains of UCH family. Anti-p28 monoclonal antibody, on injecting into the oocytes, could inhibit theprogesterone-induced resumption of meiotic division in a dose-dependent manner. The recombinant proteinp28 showed similar SDS/PAGE behaviors to the native one, and promoted ubiquitin ethyl ester hydrolysis,a classical catalytic reaction for ubiquitin carboxyl terminai hydrolases (UCHs). The results in this paperreveal that a novel protein, p28, exists in the toad oocytes, is a UCH L1 homolog, was engaged in theprocess of progesterone-induced oocyte maturation possibly through an involvement in protein turnover anddegradation.

  3. Ocorrência de Amblyomma fuscum Neumann, 1899 e Amblyomma humerale Koch, 1844 (Acari: Ixodidae em Bufo arenalis no estado de São Paulo, Brasil Occurence of Amblyomma fuscum Neumann, 1899 and Amblyomma humerale Koch, 1844 (Acari: Ixodidae in Bufo arenalis in the state of São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Afonso Lodovico Sinkoc

    1997-06-01

    Full Text Available O objetivo deste trabalho é relatar a ocorrência do parasitismo monoespecífico de A. fuscum NEUMANN, 1899 e A. humerale KOCH, 1844 em sapos (Bufo arenalis no Município de Rosana, Estado de São Paulo, Brasil. Este relato caracteriza um novo hospedeiro e uma nova localização geográfica para estas duas espécies de carrapatos.The objective of this work is to describe the occurence of the monoespecific parasitism of A. fuscum NEUMANN, 1899 and A. humerale KOCH, 1844 in toads (Bufo arenalis from the County of Rosana, State of São Paulo, Brazil. This is the description of a new host and new geographic site for those two species.

  4. Hydrosmotic effect of angiotensin II in the toad skin: role of cyclic AMP.

    Science.gov (United States)

    Coviello, A; Brauckmann, E S; de Atenor, M S; Apud, J A; Causarano, J

    1975-01-01

    The mechanism of action of the hydrosmotic response of the isolated skin of the toad Bufo arenarum Hensel to angiotensin II was studied by means of an indirect pharmacological approach. Angiotensin II (2.10(-10) M), vasopressin (2.10(-13) M) and theophylline (10(-4) and 10(-3) M) in subliminal doses produced a significant increase on water permeability when added in different paired combinations. Angiotensin II (2.10(-7) M) and vasopressin (2.10(-8) M) in doses producing significant effects on water permeability increased the response to submaximal doses of epinephrine (10(-6) M) but not to higher doses (10(-5) M). Acid pH (6.4) and prostaglandin E1 (2.10(-7) M) reduced significantly the hydrosmotic response to angiotensin II, but in contrast with the toad bladder, the effect was not completely abolished. Present results support the view that the hydrosmotic effect of angiotensin II in toad skin is mediated by the adenylate cyclase - cyclic AMP system. PMID:189568

  5. The complete mitochondrial genome of Bufo raddei.

    Science.gov (United States)

    Zhang, Wenya; Zhang, Xingjie; Guo, Rui; Tang, Yue; Zhang, Yingmei

    2016-09-01

    The complete mitochondrial genome of Bufo raddei is carried out in the present research using Illumina Hiseq 2500. The mitogenome is 17 602 bp in length and contains 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a D-loop region. The overall base composition of the H-strand is 29.15% for A, 26.09% for C, 15.16% for G, and 29.60% for T. The G + C content is 41.25%. Phylogenetic analyses of B. raddei and other 12 amphibian were carried out using Bayesian phylogenetic methods. The sequences of B. raddei were clustered in genus Bufo. PMID:26355835

  6. The complete mitochondrial genome of Bufo raddei.

    Science.gov (United States)

    Zhang, Wenya; Zhang, Xingjie; Guo, Rui; Tang, Yue; Zhang, Yingmei

    2016-09-01

    The complete mitochondrial genome of Bufo raddei is carried out in the present research using Illumina Hiseq 2500. The mitogenome is 17 602 bp in length and contains 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and a D-loop region. The overall base composition of the H-strand is 29.15% for A, 26.09% for C, 15.16% for G, and 29.60% for T. The G + C content is 41.25%. Phylogenetic analyses of B. raddei and other 12 amphibian were carried out using Bayesian phylogenetic methods. The sequences of B. raddei were clustered in genus Bufo.

  7. Effects of weather on survival in populations of boreal toads in Colorado

    Science.gov (United States)

    Scherer, R. D.; Muths, E.; Lambert, B.A.

    2008-01-01

    Understanding the relationships between animal population demography and the abiotic and biotic elements of the environments in which they live is a central objective in population ecology. For example, correlations between weather variables and the probability of survival in populations of temperate zone amphibians may be broadly applicable to several species if such correlations can be validated for multiple situations. This study focuses on the probability of survival and evaluates hypotheses based on six weather variables in three populations of Boreal Toads (Bufo boreas) from central Colorado over eight years. In addition to suggesting a relationship between some weather variables and survival probability in Boreal Toad populations, this study uses robust methods and highlights the need for demographic estimates that are precise and have minimal bias. Capture-recapture methods were used to collect the data, and the Cormack-Jolly-Seber model in program MARK was used for analysis. The top models included minimum daily winter air temperature, and the sum of the model weights for these models was 0.956. Weaker support was found for the importance of snow depth and the amount of environmental moisture in winter in modeling survival probability. Minimum daily winter air temperature was positively correlated with the probability of survival in Boreal Toads at other sites in Colorado and has been identified as an important covariate in studies in other parts of the world. If air temperatures are an important component of survival for Boreal Toads or other amphibians, changes in climate may have profound impacts on populations. Copyright 2008 Society for the Study of Amphibians and Reptiles.

  8. The dynamics of venous return and response to hypervolemia in the toad, Bufo marinus (L.)

    OpenAIRE

    Killorn, Erin E; Toews, Daniel P

    2001-01-01

    Background Venous return from the posterior region of amphibians travels by either two renal portal veins to the kidney or a central abdominal vein that drains into the hepatic portal system. The relative proportions of blood flow in these vessels has never been measured nor has a modification of flow been determined when venous return increases by changes in blood volume during hypervolemia or during increased volume input from the posterior lymph hearts. Results Venous return from the poste...

  9. Chloride transport in toad skin (Bufo viridis). The effect of salt adaptation

    DEFF Research Database (Denmark)

    Katz, U; Larsen, Erik Hviid

    1984-01-01

    ). for V = -50 mV the transepithelial Cl- conductance calculated from isotope flux measurements was 2.5 +/- 0.3 mS cm-2, N = 10. When the skin was clamped at + 50 mV the net flux of Cl- was reversed, but Cl- conductance was only 0.3 +/- 0.1 mScm-2. Flux ratio analysis indicated that the potential...

  10. Soil Organic Matter Content Effects on Dermal Pesticide Bioconcentration in American Toads (Bufo Americanus)

    Science.gov (United States)

    Agricultural landscapes serve as active amphibian breeding grounds despite their seemingly poor habitat value. Activity of adults and dispersal of metamorphs to and from agricultural ponds occurs in most species from spring through late summer or early fall, a time that coincides...

  11. Low temperature induces oocytes p34cdc2 synthesis and accumulation—the acquisition of competence to resume meiosis in toad oocytes

    Institute of Scientific and Technical Information of China (English)

    LUJINING; ZHENGGU; 等

    1996-01-01

    Full grown oocytes derived from Bufo Bufo gargarizans rearing at high temperature environment (24℃), never underwent GVBD after progesterone treatment.No p34cdc2 Hl kinase activity was detected in the oocytes after progesterone stimulation or OA microinjection;Western blotting analysis showed that the level of p34cdc2 and p33 in the oocytes are significantly lower than those in the oocytes derived from the hibernating toads (below 10℃).35S-Met incorporation analysis showed that when the oocytes were incubated at 6℃,synthesis of about thirty defferent polypeptides was promoted or induced,including p34cdc2 and some other p13suc1-binding proteins.All these results indicated that a low temperature environment is essential for the oocytes of Bufo Bufo gargarizans to express and stord some cell cycle drivers and its regulators,and to gain the maturation competence.These results will also provide a nwe clue for explaining the molecular mechanisms why gametogenesis of some organisms depends on a relative low temperature and how to maintain the geographical distribution of some animals.

  12. Post-Messinian evolutionary relationships across the Sicilian channel: Mitochondrial and nuclear markers link a new green toad from Sicily to African relatives

    Directory of Open Access Journals (Sweden)

    Lo Brutto Sabrina

    2008-02-01

    Full Text Available Abstract Background Little attention has been paid to the consequences of the last landbridge between Africa and Sicily on Mediterranean biogeography. Previous paleontological and scarce molecular data suggest possible faunal exchange later than the well-documented landbridge in the Messinian (5.3 My; however, a possible African origin of recent terrestrial Sicilian fauna has not been thoroughly tested with molecular methods. To gain insight into the phylogeography of the region, we examine two mitochondrial and two nuclear markers (one is a newly adapted intron marker in green toads (Bufo viridis subgroup across that sea barrier, the Strait of Sicily. Results Extensive sampling throughout the western Mediterranean and North Africa revealed a deep sister relationship between Sicilian (Bufo siculus n.sp. and African green toads (B. boulengeri on the mitochondrial and nuclear level. Divergence times estimated under a Bayesian-coalescence framework (mtDNA control region and 16S rRNA range from the Middle Pliocene (3.6 My to Pleistocene (0.16 My with an average (1.83 to 2.0 My around the Pliocene/Pleistocene boundary, suggesting possible land connections younger than the Messinian (5.3 My. We describe green toads from Sicily and some surrounding islands as a new endemic species (Bufo siculus. Bufo balearicus occurs on some western Mediterranean islands (Corsica, Sardinia, Mallorca, and Menorca and the Apennine Peninsula, and is well differentiated on the mitochondrial and nuclear level from B. siculus as well as from B. viridis (Laurenti, whose haplotype group reaches northeastern Italy, north of the Po River. Detection of Calabrian B. balearicus haplotypes in northeastern Sicily suggests recent invasion. Our data agree with paleogeographic and fossil data, which suggest long Plio-Pleistocene isolation of Sicily and episodic Pleistocene faunal exchange across the Strait of Messina. It remains unknown whether both species (B. balearicus, B. siculus

  13. Studies on the physiological function of spermine in the process of progesterone induced toad oocyte maturation

    Institute of Scientific and Technical Information of China (English)

    LIRUNSHENG; JIAKETSO

    1992-01-01

    Spermidine or spermine but not putrescine inhibited progesterone induced Bufo bufo gargarizans oocyte maturation.The ID50 for spermine inhibition via intra -oocyte microinjection on maturation induced by progesterone was 6.8mM(100nl).Spermine could inhibit MPF induced toad oocyte maturation with a much higher ID50.A 55 kD protein was dephosphorylated during the process of progesterone induced oocyte maturation .Spermine selectively promoted the level of phosphorylation of this protein in both progesterone-stimulated and hormone-untreated oocytes.The extent of its dephosphorylation was fairly Correlated with the percentage of GVBD in the hormone stimulated oocytes.The level of endogenous spermine was reduced by 28% between the perod of 0.40 GVBD50 and 0.60 GVBD50,at which 55 kD protein was dephosphorylated.Spermine inhibited progesterone-stimulated protein synthesis in almost the same dose dependent manner as its inhititory effect on the hormone-induced maturation,The endogenous spermine regulated 55 kD protein dephosphorylation which may trigger the increase of protein dephosphorylation which may trigger the increase of protein synthesis and in turn promote the activation of MPF,It is possible that 55 kD protein may be one of the components of messenger ribonucleoprotein(mRNP) particles.

  14. Buforins: histone H2A-derived antimicrobial peptides from toad stomach.

    Science.gov (United States)

    Cho, Ju Hyun; Sung, Bong Hyun; Kim, Sun Chang

    2009-08-01

    Antimicrobial peptides (AMPs) constitute an important component of the innate immune system in a variety of organisms. Buforin I is a 39-amino acid AMP that was first isolated from the stomach tissue of the Asian toad Bufo bufo gargarizans. Buforin II is a 21-amino acid peptide that is derived from buforin I and displays an even more potent antimicrobial activity than its parent AMP. Both peptides share complete sequence identity with the N-terminal region of histone H2A that interacts directly with nucleic acids. Buforin I is generated from histone H2A by pepsin-directed proteolysis in the cytoplasm of gastric gland cells. After secretion into the gastric lumen, buforin I remains adhered to the mucous biofilm that lines the stomach, thus providing a protective antimicrobial coat. Buforins, which house a helix-hinge-helix domain, kill a microorganism by entering the cell without membrane permeabilization and thus binding to nucleic acids. The proline hinge is crucial for the cell penetrating activity of buforins. Buforins also are known to possess anti-endotoxin and anticancer activities, thus making these peptides attractive reagents for pharmaceutical applications. This review describes the role of buforins in innate host defense; future research paradigms; and use of these agents as human therapeutics.

  15. Assessment of pollution in road runoff using a Bufo viridis biological assay

    Energy Technology Data Exchange (ETDEWEB)

    Dorchin, A., E-mail: adorchin@campus.haifa.ac.i [Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Mount Carmel, Haifa 31905 (Israel); Shanas, U., E-mail: shanas@research.haifa.ac.i [Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Mount Carmel, Haifa 31905 (Israel); Department of Biology, Faculty of Natural sciences, University of Haifa - Oranim, Tiv' on 36006 (Israel)

    2010-12-15

    Road runoff is a major source of environmental pollution, significantly threatening nearby aquatic habitats. Chemical analyses indicate high pollutant concentrations in the road's 'first flush', but bioassays are more advantageous for addressing the cumulative effects of the numerous pollutants within the runoff. We used Bufo viridis embryos and larvae to assess the toxicity of road runoff from two major highways in Israel. We show, for the first time, that exposure to midseason runoff not only has an adverse effect on growth and development rates of B. viridis larvae but can also lead to increased rates of morphological deformations. Seasonal first flushes, despite having higher metal concentrations, did not adversely affect the toad larvae, apparently due to a counter effect of organic matter that potentially served as a supplementary energy resource. Road runoff can be a major cause for a qualitative decrease in the quality of aquatic habitats threatening amphibians in Israel. - Highway runoff has detrimental effects on the development of B. viridis larvae.

  16. Effects of copper on growth, metamorphosis and endocrine disruption of Bufo gargarizans larvae.

    Science.gov (United States)

    Wang, Chao; Liang, Gang; Chai, Lihong; Wang, Hongyuan

    2016-01-01

    Chinese toad (Bufo gargarizans) tadpoles were exposed to copper (1, 6.4, 32 and 64μgL(-1) copper) from the beginning of larval period through completion of metamorphosis. We examined the effects of chronic copper exposure on mortality, growth, time to metamorphosis, tail resorption time, body size at the metamorphic climax (Gs 42) and completion of metamorphosis (Gs 46) and thyroid gland histology. In addition, type 2 and 3 iodothyronine deiodinase (Dio2 and Dio3), thyroid hormone receptors (TRα and TRβ) mRNA levels were also measured to assess disruption of TH synthesis. Our result showed that 6.4-64μgL(-1) copper concentration increased the mortality and inhibited the growth of B. gargarizans tadpoles. In addition, significant reduction in size at Gs 42 and a time delay to Gs 42 were observed at 6.4-64μgL(-1) copper treatments. Moreover, histological examinations have clearly revealed that 64μgL(-1) copper caused follicular cell hyperplasia in thyroid gland. According to real-time PCR results, exposure to 32 and 64μgL(-1) copper significantly up-regulated mRNA expression of Dio3, but down-regulated mRNA expression of TRα and TRβ mRNA level. We concluded that copper delayed amphibian metamorphosis through changing mRNA expression of Dio3, TRα and TRβ, which suggests that copper might have the endocrine-disrupting effect.

  17. Intoxicação por veneno de sapo em um canino Toad venom intoxication in a dog

    Directory of Open Access Journals (Sweden)

    Luciana Sonne

    2008-09-01

    Full Text Available O sapo do gênero Bufo possui nas suas glândulas paratóides uma secreção mucóide contendo toxinas como bufaginas e Bufotoxinas, que são esteróides cardiogênicos. Os cães podem atacar os sapos, entrando em contato com o veneno por meio das mucosas. Um canino, da raça Bulldog Francês, foi encaminhado ao Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (UFRGS para a necropsia com histórico de provável intoxicação por veneno de sapo. Na necropsia o canino apresentava pulmões aumentados de volume, avermelhados e com edema, e rins de coloração vermelho-escura. As alterações microscópicas indicaram congestão, hemorragia e edema pulmonar. Nos rins, no baço e nos linfonodos foi observada congestão. As análises toxicológicas para os venenos de rotina foram negativas. Porém, a investigação do veneno de sapo a partir de cromatografia por camada delgada e gasosa demonstrou resultado positivo, revelando ser esta a causa da morte do canino.The toads of the genus Bufo produce, in their parotoid glands, a mucoid secretion containing toxins such as bufagins and Bufotoxins, which are cardiogenic steroids. The mucous membranes of dogs can absorb this venom when they attack the toads. A French bulldog with a history of probable toad venom intoxication was referred to Veterinary Pathology Section of Federal University of Rio Grande do Sul (UFRGS for necropsy. The necropsy revealed enlarged, reddish, edematous lungs, and kidneys displaying a dark red color. The microscopic alterations indicated the presence of congestion, hemorrhage, and pulmonary edema. Congestion was observed in the kidneys, spleen and lymph nodes. The routine toxicological analyses for venom detection were negative. Nevertheless, the toad venom test result was positive as assessed by thin layer and gas chromatography, indicating that toad venom intoxication was the cause of death.

  18. Differences and Similarities among Parotoid Macrogland Secretions in South American Toads: A Preliminary Biochemical Delineation

    Directory of Open Access Journals (Sweden)

    Juliana Mozer Sciani

    2013-01-01

    Full Text Available Amphibians are known by cutaneous glands, spread over the skin, containing toxins (proteins, peptides, biogenic amines, steroidal bufadienolides, and alkaloids used as chemical defense against predators and microbial infection. Toads are characterized by the presence of parotoid macroglands. The common toads have lately been divided into two genera: Bufo (Europe, Asia, and Africa and Rhinella (South America. Basal Rhaebo genus is exclusively of Central America and Amazon region. Although Rhinella and Rhaebo are related, species may share differences due to the diversity of environments that they live in. In this work, we have performed a biochemical characterization of the components of the poison of eight Rhinella species and one Rhaebo by means of RP-HPLC with either UV or MS detection and by SDS-PAGE, in order to verify whether phylogenetic and biological differences, such as habitat, diet, and defensive strategies, between them may also be reflected in poison composition. Although some components were common among the secretions, we were able to identify exclusive molecules to some species. The fact that closely related animals living in different habitats secrete different molecules into the skin is an indication that biological features, and not only evolution, seem to directly influence the skin secretion composition.

  19. Sodium recirculation and isotonic transport in toad small intestine.

    Science.gov (United States)

    Nedergaard, S; Larsen, E H; Ussing, H H

    1999-04-01

    Isolated small intestine of toad (Bufo bufo) was mounted on glass tubes for perfusion studies with oxygenated amphibian Ringer's solution containing glucose and acetate. Under open-circuit conditions (Vt = -3.9 +/- 1.8 mV, N = 14) the preparation generated a net influx of 134Cs+. The time course of unidirectional 134Cs+-fluxes was mono-exponential with similar rate constants for influx and outflux when measured in the same preparation. The flux-ratio was time invariant from the beginning of appearance of the tracers to steady state was achieved. Thus, just a single pathway, the paracellular pathway, is available for transepithelial transport of Cs+. From the ratio of unidirectional Cs+-fluxes the paracellular force was calculated to be, 18.2 +/- 1.5 mV (N = 6), which is directed against the small transepithelial potential difference. The paracellular netflux of cesium ions, therefore, is caused by solvent drag. The flux of 134Cs+ entering and trapped by the cells was of a magnitude similar to that passing the paracellular route. Therefore, independent of the convective flux of 134Cs+, every second 134Cs+ ion flowing into the lateral space was pumped into the cells rather than proceeding, via the low resistance pathway, to the serosal bath. It is thus indicated that the paracellular convective flow of 134Cs+ is driven by lateral Na+/K+-pumps. Transepithelial unidirectional 42K+ fluxes did not reach steady state within an observation period of 70 min, indicating that components of the fluxes in both directions pass the large cellular pool of potassium ions. The ratio of unidirectional 24Na+ fluxes was time-variant and declined from an initial value of 3.66 +/- 0.34 to a significantly smaller steady-state value of 2.57 +/- 0.26 (P water-filled pores. With a new set of equations, the fraction of the sodium flux passing the basement membrane barrier of the lateral space that is recirculated through the cellular compartment is estimated. This fraction was, on average, 0

  20. Diseases of frogs and toads

    Science.gov (United States)

    Green, D.E.; Converse, K.A.; Majumdar, S.K.; Huffman, J.E.; Brenner, F.J.; Panah, A.I.

    2005-01-01

    This chapter presents information on infectious diseases of free-living frogs and toads that have completed metamorphosis. The diseases discussed in this chapter pertain principally to sub-adult and adult frogs and toads that are at least 60-90 days removed from completion of metamorphosis. The main emphasis of this chapter is the diseases found in amphibians of Canada and the United States. Diseases of recent metamorphs, larvae and amphibian eggs are presented in the chapters Diseases of Amphibian Eggs and Embryos and Diseases of Tadpoles. The smallest disease agents (viruses and bacteria) are presented first, followed by fungi, protozoa, helminths and ectoparasites. Diseases presented in this chapter are Ranaviral (iridovirus) infection Lucke frog herpesvirus (kidney cancer) Frog erythrocytic virus West Nile virus Red-leg disease (bacterial septicemia) Salmonellosis Chytrid fungal infection Basidiobolus fungi Dermosporidiosis Ichthyophoniasis Dermocystidium & Dermomycoides Myxozoa Ribeiroia flukes and Amphibian malformations Clinostomum metacercaria Aspects of each disease are presented to assist the biologist with recognition of diseases in the field. Hence, the major emphases for identification of diseases are the epizootiological aspects (host species, life stage, casualty numbers, etc) and gross findings ('lesions'). Descriptions of the microscopical, ultrastructural and cultural characteristics of each infectious agent were considered beyond the scope of this text. Detailed cultural and microscopical features of these disease agents are available in other reviews (Taylor et al., 2001; Green, 2001). Some diseases, while common in captive and zoo amphibians, are exceptionally rare in free-living frogs and toads, and therefore are omitted from this review. Among the diseases not presented are infections by chlamydia and mycobacteria, which occur principally in captive colonies of African clawed frogs (Xenopus, Hymenochirus, et al.) and northern leopard frogs

  1. Assessment of virally vectored autoimmunity as a biocontrol strategy for cane toads.

    Directory of Open Access Journals (Sweden)

    Jackie A Pallister

    Full Text Available BACKGROUND: The cane toad, Bufo (Chaunus marinus, is one of the most notorious vertebrate pests introduced into Australia over the last 200 years and, so far, efforts to identify a naturally occurring B. marinus-specific pathogen for use as a biological control agent have been unsuccessful. We explored an alternative approach that entailed genetically modifying a pathogen with broad host specificity so that it no longer caused disease, but carried a gene to disrupt the cane toad life cycle in a species specific manner. METHODOLOGY/PRINCIPAL FINDINGS: The adult beta globin gene was selected as the model gene for proof of concept of autoimmunity as a biocontrol method for cane toads. A previous report showed injection of bullfrog tadpoles with adult beta globin resulted in an alteration in the form of beta globin expressed in metamorphs as well as reduced survival. In B. marinus we established for the first time that the switch from tadpole to adult globin exists. The effect of injecting B. marinus tadpoles with purified recombinant adult globin protein was then assessed using behavioural (swim speed in tadpoles and jump length in metamorphs, developmental (time to metamorphosis, weight and length at various developmental stages, protein profile of adult globin and genetic (adult globin mRNA levels measures. However, we were unable to detect any differences between treated and control animals. Further, globin delivery using Bohle iridovirus, an Australian ranavirus isolate belonging to the Iridovirus family, did not reduce the survival of metamorphs or alter the form of beta globin expressed in metamorphs. CONCLUSIONS/SIGNIFICANCE: While we were able to show for the first time that the switch from tadpole to adult globin does occur in B. marinus, we were not able to induce autoimmunity and disrupt metamorphosis. The short development time of B. marinus tadpoles may preclude this approach.

  2. critical habitat designated for the arroyo toad

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These data identify the areas (in general) of critical habitat designated for the arroyo toad. NOTE: THIS DATA SET INCLUDES APPROXIMATELY 900 ACRES OF LAND...

  3. Anomalías oculares en híbridos Bufo paranecmis ♂ x Bufo arenarum ♀ (Anura: Bufonidae

    Directory of Open Access Journals (Sweden)

    Rengel, Dora

    1994-01-01

    Full Text Available Los híbridos entre Bufo paracnemis x Bufo arenarum se encuadran en los llamados "híbridos vitales". Los resultados han evidenciado relevantes anomalías oculares que se manifiestan en un 90% de los casos. En algunas larvas falta el cristalino tanto en uno como en ambos ojos (20%; en otras larvas el cristalino se encuentra ubicado en posición opuesta al normal (25% o bien puede ocurrir que se forme un ojo normal y el otro de forma distinta (20%. El análisis histológico mostró anomalías en la zona retiniana, evidenciándose a partir de los estratos pigmentarios, repliegues y movimientos flexuosos (5%. También existen ojos replegados sobre sí mismos (5%. Las alteraciones más severas llevaron a procesos de anoftalmia (10%. En ocasiones (5% en lugar del ojo se evidencian grumos de pigmento. Se obtuvo un 10% con ojos normales. Los otros órganos presentan analogía con los de las larvas de Bufo paracnemis, inclusive la librea dorsal. The hybrids between Bufo paracnemis x Bufo arenarum are counted among tbe so called "vital hybrids". Our results have revealed relevant ocular anomalies in 90% of cases. In some larvae the lens is lacking in either one or both eyes (20%; in others the lens it is found in an opposite position to normal (25% or else one normal and one different eye is formed (20%. Histological analysis reveals anomalies in the retinal area, observing flexuous movements in the pigmentary strata (5%. Eyes folded over themselves were also observed (5%. The most severe alterations produced cases of anophtalmia (10%. On occasions (5%, groupings of pigments were found instead of the eyes. l0% of the larvae were normal. The other organs show analogies to those of the larvae of Bufo paracnemis, including the dorsal pattem.

  4. Molecular cloning and analysis of Myc modulator 1 (Mm-1 from Bufo gargarizans (Amphibia: Anura

    Directory of Open Access Journals (Sweden)

    Ning Wang

    2010-02-01

    Full Text Available The protein of Myc modulator 1 (Mm-1 has been reported to repress the transcriptional activity of the proto-oncogene c-Myc in humans. Moreover, it was shown to be the subunit 5 of human prefoldin (PFD. So far, this gene and its homologs have been isolated and sequenced in many organisms, such as mammals and fish, but has not been sequenced for any amphibian or reptile. In order to better understand the function and evolution of Mm-1, we isolated a full-length Mm-1 cDNA (BgMm-1, GenBank accession no. EF211947 from Bufo gargarizans (Cantor, 1842 using RACE (rapid amplification of cDNA ends methods. Mm-1 in B. gargarizans is 755 bp long, comprising an open reading frame (ORF of 459 bp encoding 152 amino acids. The amino acid sequence had a prefoldin α-like domain, partially including a typical putative leucine zipper motif. BgMm-1 showed high similarity to its homolog of Mus musculus Linnaeus, 1758 (82% and Homo sapiens Linnaeus, 1758 MM-1 isoform a (81% at the amino acid level. The protein secondary structure modeled with the SWISS MODEL server revealed that there were two α-helices and four b-strands in BgMm-1 as its human orthologue, and both proteins belonged to the a class of PFD family. The phylogenetic relationships of Mm-1s from lower archaea to high mammals was consistent with the evolution of species, meanwhile the cluster result was consistent with the multiple alignment and the sequence identity analysis. RT-PCR (reverse transcriptase-polymerase chain reaction analysis demonstrated that BgMm-1 expressed widely in ten tissues of adult toad. These results can be helpful for the further investigation on the evolution of Mm-1.

  5. Male size does not correlate with fertilization success in two bufonid toads that show size-assortative mating

    Directory of Open Access Journals (Sweden)

    Xiao-Li FAN, Zhi-Hua LIN, Xiang JI

    2013-12-01

    Full Text Available We examined sexual size dimorphism (SSD, mating pattern, fertilization efficiency and female reproductive traits in two bufonid toads (Bufo gargarizans and Duttaphrynus melanostictus to test the idea that importance of male body size for egg fertilization success depends on the mating pattern. Female-biased SSD was evident only in D. melanostictus. Female B. gargarizans laid fewer larger eggs nearly three months earlier than did female D. melanostictus. Fertilization efficiencies on average were higher in B. gargarizans (95% than in D. melanostictus (91%. Though differing in the degree of SSD, body size, breeding season, clutch size, egg size and fertilization efficiency, the two toads were similar in four aspects: (1 both showed size-assortative mating; (2 females did not tradeoff egg size against egg number; (3 male size, clutch size and clutch dry mass were greater in male-larger than in female-larger pairs after accounting for female snout-vent length (SVL; and (4 the ratio of male to female SVL did not affect fertilization efficiency. Our data show that: (1 a female preference for large males is likely not important in terms of egg fertilization success; (2 a male preference for large females is likely important because larger females are more fecund; and (3 size-assortative mating arises from a male preference for large females. Our study demonstrates that male size is not always important for egg fertilization success in anurans that show size-assortative mating [Current Zoology 59 (6: 740–746, 2013].

  6. Landscape associations of frog and toad species in Iowa and Wisconsin, U.S.A

    Science.gov (United States)

    Knutson, M.G.; Sauer, J.R.; Olsen, D.A.; Mossman, M.J.; Hemesath, L.M.; Lannoo, M.J.; Kaiser, Hinrich; Casper, Gary S.; Bernstein, Neil P.

    2000-01-01

    Landscape habitat associations of frogs and toads in Iowa and Wisconsin were tested to determine whether they support or refute previous general habitat classifications. We examined which Midwestern species shared similar habitats to see if these associations were consistent across large geographic areas (states). Rana sylvatica (wood frog), Hyla versicolor (eastern gray treefrog), Pseudacris crucifer (spring peeper), and Acris crepitans (cricket frog) were identified as forest species, P. triseriata (chorus frog), H. chrysoscelis (Cope's gray treefrog), R. pipiens (leopard frog), and Bufo americanus (American toad) as grassland species, and R. catesbeiana (bullfrog), R. clamitans (green frog), R. palustris (pickerel frog), and R. septentrionalis (mink frog) as lake or stream species. The best candidates to serve as bioindicators of habitat quality were the forest species R. sylvatica, H. versicolor, and P. crucifer, the grassland species R. pipiens and P. triseriata, and a cold water wetland species, R. palustris. Declines of P. crucifer, R. pipiens, and R. palustris populations in one or both states may reflect changes in habitat quality. Habitat and community associations of some species differed between states, indicating that these relationships may change across the range of a species. Acris crepitans may have shifted its habitat affinities from open habitats, recorded historically, to the more forested habitat associations we recorded. We suggest contaminants deserve more investigation regarding the abrupt and widespread declines of this species. Interspersion of different habitat types was positively associated with several species. A larger number of wetland patches may increase breeding opportunities and increase the probability of at least one site being suitable. We noted consistently negative associations between anuran species and urban development. Given the current trend of urban growth and increasing density of the human population, declines of

  7. Sulfate transport in toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Simonsen, K

    1988-01-01

    -circuited preparations resulted in a significant stimulation of the passive Cl- and SO2(-4) permeabilities. 6. It is suggested that SO2(-4) and Cl- ions are transported along the same pathway of the m.r. cells. Depending on the transport mode of the apical Cl- transport system, electro-diffusion, active transport......1. In short-circuited toad skin preparations exposed bilaterally to NaCl-Ringer's containing 1 mM SO2(-4), influx of sulfate was larger than efflux showing that the skin is capable of transporting sulfate actively in an inward direction. 2. This active transport was not abolished by substituting...... apical Na+ for K+. 3. Following voltage activation of the passive Cl- permeability of the mitochondria-rich (m.r.) cells sulfate flux-ratio increased to a value predicted from the Ussing flux-ratio equation for a monovalent anion. 4. In such skins, which were shown to exhibit vanishingly small leakage...

  8. Habitat suitability of patch types:A case study of the Yosemite toad

    Institute of Scientific and Technical Information of China (English)

    Christina T.LIANG; Thomas J.STOHLGREN

    2011-01-01

    Understanding patch variability is crucial in understanding the spatial population structure of wildlife species,especially for rare or threatened species.We used a well-tested maximum entropy species distribution model (Maxent) to map the Yosemite toad (Anaxyrus (= Bufo) canorus) in the Sierra Nevada mountains of California.Twenty-six environmental variables were included in the model representing climate,topography,land cover type,and disturbance factors (e.g.,distances to agricultural lands,fire perimeters,and timber harvest areas) throughout the historic range of the toad.We then took a novel approach to the study of spatially structured populations by applying the species-environmental matching model separately for 49 consistently occupied sites of the Yosemite toad compared to 27 intermittently occupied sites.We found that the distribution of the entire population was highly predictable (AUC= 0.95±0.03 SD),and associated with low slopes,specific vegetation types (wet meadow,alpine-dwarf shrub,montane chaparral,red fir,and subalpine conifer),and warm temperatures.The consistently occupied sites were also associated with these same factors,and they were also highly predictable (AUC= 0.95±0.05 SD).However,the intermittently occupied sites were associated with distance to fire perimeter,a slightly different response to vegetation types,distance to timber harvests,and a much broader set of aspect classes (AUC = 0.90±0.11 SD).We conclude that many studies of species distributions may benefit by modeling spatially structured populations separately.Modeling and monitoring consistently-occupied sites may provide a realistic snapshot of current speciesenvironment relationships,important climatic and topographic patterns associated with species persistence patterns,and an understanding of the plasticity of the species to respond to varying climate regimes across its range.Meanwhile,modeling and monitoring of widely dispersing individuals and intermittently occupied

  9. The toxicity of glyphosate alone and glyphosate-surfactant mixtures to western toad (Anaxyrus boreas) tadpoles.

    Science.gov (United States)

    Vincent, Kim; Davidson, Carlos

    2015-12-01

    Pesticide choice based on toxicity to nontarget wildlife is reliant on available toxicity data. Despite a number of recent studies examining the effects of glyphosate on amphibians, very few have aimed to understand the toxicological effects of glyphosate in combination with surfactants as it is commonly applied in the field. Land managers interested in making pesticide choices based on minimizing impacts to nontarget wildlife are hindered by a lack of published toxicity data. Short-term acute toxicity trials were conducted for glyphosate in the form of isopropylamine salt (IPA) alone and mixed with 2 surfactants: Agri-dex and Competitor with western toad (Anaxyrus [Bufo] boreas) tadpoles. Glyphosate IPA mixed with Competitor was 6 times more toxic than glyphosate IPA mixed with Agri-dex, and both mixtures were more toxic than glyphosate IPA alone. The median lethal concentrations reported for 24-h and 48-h exposures were 8279 mg/L (24 h) and 6392 mg/L (48 h) for glyphosate IPA alone; 5092 mg/L (24 h) and 4254 mg/L (48 h) for glyphosate IPA mixed with Agri-dex; and 853 mg/L (24 h) and 711 mg/L (48 h) for glyphosate IPA mixed with Competitor. The present study indicates that the toxicity of a tank mix may be greatly increased by the addition of surfactants and may vary widely depending on the specific surfactant.

  10. Effects of ADH on the apical and basolateral membranes of toad urinary bladder epithelial cells.

    Science.gov (United States)

    Donaldson, P J; Leader, J P

    1993-11-01

    Short-circuited urinary bladders from Bufo marinus were supported on their apical surface by an agar mounting method and impaled with microelectrodes via their basolateral membrane. This arrangement provided stable and long-lasting impalements of epithelial cells and yielded reliable membrane potentials and voltage divider ratios (Ra/Rb), where Ra and Rb are apical and basolateral membrane resistances respectively. The membrane potential under short-circuit conditions (Vsc) was -51.4 +/- 2.2 mV (n = 59), while under open-circuit conditions apical membrane potential (Va) and basolateral membrane potential (Vb) were -31.0 +/- 2.4 and 59.5 +/- 2.4 mV, respectively. This yields a "well-shaped" potential profile across the toad urinary bladder, where Va is inversely related to the rate of transport, Isc. Antidiuretic hormone (ADH) produced a hyperpolarisation of Vsc and Vb but had no significant effect on Va. In addition, Ra/Rb was significantly increased by ADH (4.6 +/- 0.5 to 10.2 +/- 3.6). Calculation of individual membrane resistances following the addition of amiloride showed that ADH produced a parallel decrease in Ra and Rb membrane resistance, with the observed increase in Ra/Rb being due to a greater percentage decrease in Rb than in Ra. The ability of ADH to effect parallel changes in apical and basolateral membrane conductance helps to maintain a constant cellular volume despite an increase in transepithelial transport. PMID:8309781

  11. JUVENILE WESTERN TOADS, BUFO BOREAS, AVOID CHEMICAL CUES OF SNAKES FED JUVENILE, BUT NOT LARVAL, CONSPECIFICS. (U915529)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  12. The dynamics of venous return and response to hypervolemia in the toad, Bufo marinus (L.)

    OpenAIRE

    Toews Daniel P; Killorn Erin E

    2001-01-01

    Abstract Background Venous return from the posterior region of amphibians travels by either two renal portal veins to the kidney or a central abdominal vein that drains into the hepatic portal system. The relative proportions of blood flow in these vessels has never been measured nor has a modification of flow been determined when venous return increases by changes in blood volume during hypervolemia or during increased volume input from the posterior lymph hearts. Results Venous return from ...

  13. Wyoming toad, Bufo hemiophrys baxteri, habitat use and hibernaculum research project with the use of telemetry : Annual report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual report is on a two year study, started in 1998, to evaluate the daily and seasonal habitat use to determine the location of the hibemaculum of the...

  14. THE EFFECT OF SUBSTRATE TYPE ON AVOIDANCE OF UREA IN JUVENILE WESTERN TOADS (BUFO BOREAS). (U915529)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  15. Comparative cytogenetic studies of Bufo ictericus, B. paracnemis (Amphibia, Anura and an intermediate form in sympatry

    Directory of Open Access Journals (Sweden)

    Azevedo MFC

    2003-01-01

    Full Text Available Specimens of Bufo ictericus, Bufo paracnemis and a third type, considered an intermediate subgroup between these species, were cytogenetically studied by conventional Giemsa staining, C-banding and staining of the nucleolus organizer region (NOR. The nuclear DNA content and seroproteins were also analyzed to characterize these species, and verify the possibility of hybridization between them. Karyotypes and cytogenetic markers were essentially equal on the basis of the methods used. The DNA nuclear content found was 6.25 ± 0.30 pg/DNA in Bufo ictericus; 7.57 ± 0.40 pg/DNA in Bufo paracnemis and 7.04 ± 0.29 pg/DNA in the intermediate subgroup. Eletrophoresis of total blood serum in Bufo ictericus, Bufo paracnemis and the intermediate specimens revealed a remarkable difference in the patterns of the protein bands whose molecular weight corresponded to that of albumin. While the parental species presented two different bands, the intermediate form presented 4. However, only three of these bands were seen in each specimen. The results obtained pointed to a high probability for natural hybridization between Bufo ictericus and Bufo paracnemis in the site and specimens studied.

  16. Toads on Lava: Spatial Ecology and Habitat Use of Invasive Cane Toads (Rhinella marina) in Hawai’i

    OpenAIRE

    Georgia Ward-Fear; Greenlees, Matthew J.; Richard Shine

    2016-01-01

    Most ecological research on cane toads (Rhinella marina) has focused on invasive populations in Australia, ignoring other areas where toads have been introduced. We radio-tracked and spool-tracked 40 toads, from four populations on the island of Hawai'i. Toads moved extensively at night (mean 116 m, from spool-tracking) but returned to the same or a nearby retreat-site each day (from radio-tracking, mean distance between successive retreat sites 11 m; 0 m for 70% of records). Males followed s...

  17. Sexual selection in cane toads Rhinella marina: A male’s body size affects his success and his tactics

    Directory of Open Access Journals (Sweden)

    Haley BOWCOCK, Gregory P. BROWN, Richard SHINE

    2013-12-01

    Full Text Available Male body size can play an important role in the mating systems of anuran amphibians. We conducted laboratory-based trials with cane toads Rhinella (Bufo marina from an invasive population in the wet-dry tropics of northern Australia, to clarify the effects of a male's body size on his reproductive success and behavior (mate choice. Males were stimulated with a synthetic hormone to induce reproductive readiness. Larger body size enhanced a male toad's ability to displace a smaller rival from amplexus, apparently because of physical strength: more force was required to dislodge a larger than a smaller amplectant male. A male’s body size also affected his mate-choice criteria. Males of all body sizes were as likely to attempt amplexus with another male as with a female of the same size, and preferred larger rather than smaller sexual targets. However, this size preference was stronger in larger males and hence, amplexus was size-assortative. This pattern broke down when males were given access to already-amplectant male-female pairs: males of all body sizes readily attempted amplexus with the pair, with no size discrimination. An amplectant pair provides a larger visual stimulus, and prolonged amplexus provides a strong cue for sex identification (one of the individuals involved is almost certainly a female. Thus, a male cane toad’s body size affects both his ability to defeat rivals in physical struggles over females, and the criteria he uses when selecting potential mates, but the impacts of that selectivity depend upon the context in which mating occurs [Current Zoology 59 (6: 747–753, 2013].

  18. Aerobic scope and cardiovascular oxygen transport is not compromised at high temperatures in the toad Rhinella marina.

    Science.gov (United States)

    Overgaard, Johannes; Andersen, Jonas L; Findsen, Anders; Pedersen, Pil B M; Hansen, Kasper; Ozolina, Karlina; Wang, Tobias

    2012-10-15

    Numerous recent studies convincingly correlate the upper thermal tolerance limit of aquatic ectothermic animals to reduced aerobic scope, and ascribe the decline in aerobic scope to failure of the cardiovascular system at high temperatures. In the present study we investigate whether this 'aerobic scope model' applies to an air-breathing and semi-terrestrial vertebrate Rhinella marina (formerly Bufo marinus). To quantify aerobic scope, we measured resting and maximal rate of oxygen consumption at temperatures ranging from 10 to 40°C. To include potential effects of acclimation, three groups of toads were acclimated chronically at 20, 25 and 30°C, respectively. The absolute difference between resting and maximal rate of oxygen consumption increased progressively with temperature and there was no significant decrease in aerobic scope, even at temperature immediately below the lethal limit (41-42°C). Haematological and cardiorespiratory variables were measured at rest and immediately after maximal activity at benign (30°C) and critically high (40°C) temperatures. Within this temperature interval, both resting and active heart rate increased, and there was no indication of respiratory failure, judged from high arterial oxygen saturation, P(O2) and [Hb(O2)]. With the exception of elevated resting metabolic rate for cold-acclimated toads, we found few differences in the thermal responses between acclimation groups with regard to the cardiometabolic parameters. In conclusion, we found no evidence for temperature-induced cardiorespiratory failure in R. marina, indicating that maintenance of aerobic scope and oxygen transport is unrelated to the upper thermal limit of this air-breathing semi-terrestrial vertebrate.

  19. Toads on Lava: Spatial Ecology and Habitat Use of Invasive Cane Toads (Rhinella marina in Hawai'i.

    Directory of Open Access Journals (Sweden)

    Georgia Ward-Fear

    Full Text Available Most ecological research on cane toads (Rhinella marina has focused on invasive populations in Australia, ignoring other areas where toads have been introduced. We radio-tracked and spool-tracked 40 toads, from four populations on the island of Hawai'i. Toads moved extensively at night (mean 116 m, from spool-tracking but returned to the same or a nearby retreat-site each day (from radio-tracking, mean distance between successive retreat sites 11 m; 0 m for 70% of records. Males followed straighter paths during nocturnal movements than did females. Because moist sites are scarce on the highly porous lava substrate, Hawai'ian toads depend on anthropogenic disturbance for shelter (e.g. beneath buildings, foraging (e.g. suburban lawns, golf courses and breeding (artificial ponds. Foraging sites are further concentrated by a scarcity of flying insects (negating artificial lights as prey-attractors. Habitat use of toads shifted with time (at night, toads selected areas with less bare ground, canopy, understory and leaf-litter, and differed between sexes (females foraged in areas of bare ground with dense understory vegetation. Cane toads in Hawai'i thrive in scattered moist patches within a severely arid matrix, despite a scarcity of flying insects, testifying to the species' ability to exploit anthropogenic disturbance.

  20. Toads on Lava: Spatial Ecology and Habitat Use of Invasive Cane Toads (Rhinella marina) in Hawai'i.

    Science.gov (United States)

    Ward-Fear, Georgia; Greenlees, Matthew J; Shine, Richard

    2016-01-01

    Most ecological research on cane toads (Rhinella marina) has focused on invasive populations in Australia, ignoring other areas where toads have been introduced. We radio-tracked and spool-tracked 40 toads, from four populations on the island of Hawai'i. Toads moved extensively at night (mean 116 m, from spool-tracking) but returned to the same or a nearby retreat-site each day (from radio-tracking, mean distance between successive retreat sites 11 m; 0 m for 70% of records). Males followed straighter paths during nocturnal movements than did females. Because moist sites are scarce on the highly porous lava substrate, Hawai'ian toads depend on anthropogenic disturbance for shelter (e.g. beneath buildings), foraging (e.g. suburban lawns, golf courses) and breeding (artificial ponds). Foraging sites are further concentrated by a scarcity of flying insects (negating artificial lights as prey-attractors). Habitat use of toads shifted with time (at night, toads selected areas with less bare ground, canopy, understory and leaf-litter), and differed between sexes (females foraged in areas of bare ground with dense understory vegetation). Cane toads in Hawai'i thrive in scattered moist patches within a severely arid matrix, despite a scarcity of flying insects, testifying to the species' ability to exploit anthropogenic disturbance. PMID:27027738

  1. Bufo toxin: A new testing prospect for the screening of anti-convulsant agents. A review

    Directory of Open Access Journals (Sweden)

    David Arome

    2014-07-01

    Full Text Available Epilepsy is a common neurological disorder with diverse aetiology, affecting approximately 1 % of the entire population. Epilepsy present wide range of clinical manifestations, that affect the way a person feels and acts for a short time. Previous scientific investigations have indicated bufo toxin as a potential convulsant candidate that produced similar effects as other known convulsant agents. Bufo toxin has been shown to mimic or exhibit similar action as other known convulsant agent. Its biochemical components are formed as a result of the binding of bufo-fagin and a molecule arginina. There exist wide array of convulsant agents used in the screening of anti-convulsant agents. The commonly used one are: bicuculline, picrotoxin, pentylene tetrazole, isonizid etc. However, these agents are expensive, not easily available and affordable. This challenge prompted the search of other alternative convulsant agents that is easily accessible for use in the screening of anti-convulsant agents. The principal objective of this review paper is to suggest the possible use of bufo toxin which mimics the action of existing convulsant agents. This new testing convulsant agent (bufo toxin is inexpensive, affordable and easy to use when compared to other known convulsant agents. The experimental procedure is easy and it gives a broad spectrum in comparing the action of bufo toxin to other chemical convulsant agents. It also offers researchers broader view or options in exploring the anti-convulsant activity of test agents and the understanding of their possible mechanism of action.

  2. Biogeographic patterns of Colombian frogs and toads

    International Nuclear Information System (INIS)

    Using the data provided in Ruiz-Carranza et al. (1996) the distributions of the 540 species of frogs and toads are partitioned among ten ecogeographic units of Colombia defined on the basis of precipitation and elevation. Some lowlands areas (pacific lowlands, Amazonian) exhibit high diversity (85-94 species) but lowlands areas in general are impoverished (30-52 species), especially when contrasted with upland areas. The three Andean cordilleras harbor between 87 and 121 species of frogs and toads, demonstrating that the biodiversity of Colombia resides primarily in its montane components, not in its lowland rain forests. When biological endemicity is separated from political endemicity, five areas of high endemicity remain (the three Andean cordilleras, the Sierra Nevada de Santa Marta, and the pacific lowlands). We endeavor to explain this description by recourse to cladistic analyses of several groups of leptodactylid frogs where we find that the general pattern of diversification is by means of horizontal diversification (allopatric speciation) with a minor contribution from vertical diversification

  3. Stereological analysis of mitochondria in embryos of Rana temporaria and Bufo bufo during cleavage

    Directory of Open Access Journals (Sweden)

    Ewa Krzysztofowicz

    2011-08-01

    Full Text Available Total numbers of mitochondria and their morphology have been quantitatively determined in mature oocytes and in cleaving embryos of two anuran species Rana temporaria and Bufo bufo using stereological methods. Surface densities of inner mitochondrial membranes for both studied species during cleavage ranged from 5.43 m2/cm3 to 7.53 m2/cm3, whereas volume densities of mitochondria did not exceed 1.65%. Since values of these parameters were low, thus embryos during cleavage may be considered as metabolically "silent". Transition of ultrastructural morphology of mitochondria towards that characterising actively respiring organelles occurs at stage 9 for R. temporaria and at stage 8 for B. bufo, correlated with blastula-gastrula and mid-blastula transition, respectively. The total numbers of mitochondria N(c in mature oocytes are as high as 114.8 and 107.2 millions for R. temporaria and B. bufo, respectively, and during cleavage at late blastula stages they increase to 300 millions for both species under study. We suggest that an undefined mechanism might eliminate during cleavage those amphibian embryos which contain small number of mitochondria and low levels of nutrient substances.

  4. Diet of Physalaemus cf. cicada (Leptodactylidae) and Bufo granulosus (Bufonidae) in a semideciduous forest.

    Science.gov (United States)

    Santana, A S; Juncá, F A

    2007-02-01

    We determined the diet of the two most abundant anuran species which occur in the litter of a semideciduous forest (Lençóis, Bahia, Brazil), Physalaemus cf. cicada and Bufo granulosus in the dry and rainy seasons. Pitfall traps were used to collect anuran and invertebrate fauna, which showed the availability of prey in the environment. Physalaemus cf. cicada was present in both seasons and Bufo granulosus only in the rainy season. Both species fed mainly on Isoptera and Formicidae. However, there is a difference between the rainy and dry seasons concerning the diet of P. cf. cicada. During the rainy season P. cf. cicada consumed less Isoptera and more Formicidae than in the dry season. In the volumetric sense, Orthoptera was the most important alimentary category for P. cf. cicada and B. granulosus. The Jacobs electivity index indicated that Physalaemus cf. cicada and Bufo granulosus were specialists in Isoptera. PMID:17505759

  5. The envelopes of amphibian oocytes: physiological modifications in Bufo arenarum

    Directory of Open Access Journals (Sweden)

    Sánchez Mercedes

    2003-02-01

    Full Text Available Abstract A characterization of the Amphibian Bufo arenarum oocyte envelope is presented. It was made in different functional conditions of the oocyte: 1 when it has been released into the coelomic cavity during ovulation (surrounded by the coelomic envelope, (CE, 2 after it has passed through the oviduct and is deposed (surrounded by the viteline envelope, (VE, and 3 after oocyte activation (surrounded by the fertilization envelope, (FE. The characterization was made by SDS-PAGE followed by staining for protein and glycoproteins. Labeled lectins were used to identify glycosidic residues both in separated components on nitrocellulose membranes or in intact oocytes and embryos. Proteolytic properties of the content of the cortical granules were also analyzed. After SDS-PAGE of CE and VE, a different protein pattern was observed. This is probably due to the activity of a protease present in the pars recta of the oviduct. Comparison of the SDS-PAGE pattern of VE and FE showed a different mobility for one of the glycoproteins, gp75. VE and FE proved to have different sugar residues in their oligosaccharide chains. Mannose residues are only present in gp120 of the three envelopes. N-acetyl-galactosamine residues are present in all of the components, except for gp69 in the FE. Galactose residues are present mainly in gp120 of FE. Lectin-binding assays indicate the presence of glucosamine, galactose and N-acetyl galactosamine residues and the absence (or non-availability of N-acetyl-glucosamine or fucose residues on the envelopes surface. The cortical granule product (CGP shows proteolytic activity on gp75 of the VE.

  6. The supercritical CO₂ extract from the skin of Bufo bufo gargarizans Cantor blocks hepatitis B virus antigen secretion in HepG2.2.15 cells.

    Science.gov (United States)

    Cui, Xiaoyan; Inagaki, Yoshinori; Wang, Dongliang; Gao, Jianjun; Qi, Fanghua; Gao, Bo; Kokudo, Norihiro; Fang, Dingzhi; Tang, Wei

    2014-02-01

    The skin of Bufo bufo gargarizans Cantor has long been used for the treatment of hepatitis B in China and supercritical carbon dioxide extraction (SC-CO₂) is widely used in extracting active ingredients from natural products. The aim of present study was to assess the anti-hepatitis B virus (HBV) effect of the supercritical CO₂ extract from the skin of Bufo bufo gargarizans Cantor (SCE-BC). Cytotoxicity of SCE-BC was analyzed using an MTT [3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide] assay in HepG2.2.15 cells. The hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and hepatitis B core-related antigen (HBcrAg) concentrations in cell culture medium were determined by chemiluminescent enzyme immunoassay. HBV mRNA in cells was determined using real-time polymerase chain reaction. SCE-BC concentrations below 10(-2) μg/mL had no significant toxicity to HepG2.2.15 cells. SCE-BC at 10(-4) μg/mL effectively inhibited the secretion of HBeAg by 23.36% on day 6. It was more potent than the positive control lamivudine (100 μg/mL) in terms of the inhibition of HBeAg and HBcrAg secretion on day 6. Consistent with the HBV antigen reduction, HBV mRNA expression was markedly inhibited in comparison to the control when HepG2.2.15 cells were treated with SCE-BC. Moreover, SCE-BC had greater inhibitory activity with respect to HBeAg than to HBsAg. Since HBeAg promotes immune tolerance and persistent infection during HBV infection, the present results suggest that immune tolerance induced by HBeAg might be overcome by SCE-BC. Therefore, SCE-BC warrants further investigation.

  7. Thermal effects on the dynamics and motor control of ballistic prey capture in toads: maintaining high performance at low temperature.

    Science.gov (United States)

    Deban, Stephen M; Lappin, A Kristopher

    2011-04-15

    Temperature has a strong influence on biological rates, including the contractile rate properties of muscle and thereby the velocity, acceleration and power of muscle-powered movements. We hypothesized that the dynamics of movements powered by elastic recoil have a lower thermal dependence than muscle-powered movements. We examined the prey capture behavior of toads (Bufo terrestris) using high speed imaging and electromyography to compare the effects of body temperature (11-35°C) on the kinematics, dynamics and motor control of two types of movement: (1) ballistic mouth opening and tongue projection, which are powered by elastic recoil, and (2) non-ballistic prey transport, including tongue retraction and mouth closing, which are powered directly by muscle contraction. Over 11-25°C, temperature coefficients of ballistic mouth opening and tongue projection dynamics (Q(10) of 0.99-1.25) were not significantly different from 1.00 and were consistently lower than those of prey transport movements (Q(10) of 1.77-2.26), supporting our main hypothesis. The depressor mandibulae muscle, which is responsible for ballistic mouth opening and tongue projection via the recovery of elastic strain energy stored by the muscle prior to the onset of the movement, was activated earlier and for a longer duration at lower temperatures (Q(10) of 2.29-2.41), consistent with a slowing of its contractile rates. Muscle recruitment was unaffected by temperature, as revealed by the lack of thermal dependence in the intensity of activity of both the jaw depressor and jaw levator muscles (Q(10) of 0.754-1.12). Over the 20-35°C range, lower thermal dependence was found for the dynamics of non-elastic movements and the motor control of both elastic and non-elastic movements, in accord with a plateau of high performance found in other systems.

  8. A network extension of species occupancy models in a patchy environment applied to the Yosemite toad (Anaxyrus canorus)

    Science.gov (United States)

    Berlow, Eric L.; Knapp, Roland A.; Ostoja, Steven M.; Williams, Richard J.; McKenny, Heather; Matchett, John R.; Guo, Qinghau; Fellers, Gary M.; Kleeman, Patrick; Brooks, Matthew L.; Joppa, Lucas

    2013-01-01

    A central challenge of conservation biology is using limited data to predict rare species occurrence and identify conservation areas that play a disproportionate role in regional persistence. Where species occupy discrete patches in a landscape, such predictions require data about environmental quality of individual patches and the connectivity among high quality patches. We present a novel extension to species occupancy modeling that blends traditionalpredictions of individual patch environmental quality with network analysis to estimate connectivity characteristics using limited survey data. We demonstrate this approach using environmental and geospatial attributes to predict observed occupancy patterns of the Yosemite toad (Anaxyrus (= Bufo) canorus) across >2,500 meadows in Yosemite National Park (USA). A. canorus, a Federal Proposed Species, breeds in shallow water associated with meadows. Our generalized linear model (GLM) accurately predicted ~84% of true presence-absence data on a subset of data withheld for testing. The predicted environmental quality of each meadow was iteratively ‘boosted’ by the quality of neighbors within dispersal distance. We used this park-wide meadow connectivity network to estimate the relative influence of an individual Meadow’s ‘environmental quality’ versus its ‘network quality’ to predict: a) clusters of high quality breeding meadows potentially linked by dispersal, b) breeding meadows with high environmental quality that are isolated from other such meadows, c) breeding meadows with lower environmental quality where long-term persistence may critically depend on the network neighborhood, and d) breeding meadows with the biggest impact on park-wide breeding patterns. Combined with targeted data on dispersal, genetics, disease, and other potential stressors, these results can guide designation of core conservation areas for A. canorus in Yosemite National Park.

  9. Tissue kinetics, ion transport, and recruitment of mitochondria-rich cells in the skin of the toad (Bufo bufo) in response to exposure to distilled water

    DEFF Research Database (Denmark)

    Budtz, Poul Egede; Christoffersen, Betina C.; Johansen, Jesper S.;

    1995-01-01

    Mitochondria-rich cells (MRC) of the amphibian epidermis are responsible for active chloride uptake at low external salinity, and new MRCs are recruited in response to exposure to distilled (deionized) water. The time-course of this recruitment, the tissue kinetics and ion transport have been...

  10. 除草剂丁草胺对蟾蜍肝脏形态学和组织学的毒性作用%Toxicity effect of herbicide butachlor on hepatic morphologic and histology of bufo bufo gargarizans

    Institute of Scientific and Technical Information of China (English)

    王勇; 边邵康; 梁传成; 王丽文

    2012-01-01

    Objective :To observe influence of the herbicide butachlor on hepatic morphologic and histology of Bufo bufo gargarizans. To study toxicity of herbicide butachlor on liver of Bufo bufo. Method: The Bufo bufo gargarizans were randomly divided into control group, paddy goup, S times paddy group, 10 times paddy group ( n = 15 ), the control groups and experimental groups were placed apart in aerated water and in experimental barrels containing butachlor( 5, 10, 30 ml/L) , 1/2 of the body of Bufo bufo gargarizans was immersed in the sulotion. After 3,6, and 9 days, five Bufo bufo were randomly selected from each group and they were dissected to observe the modality and to measure the coefficient of liver. The paraffin slice and HE dyeing were used to observe the structure of liver. Result: The time and concentration of dyeing poison can affect the hepatic modality and structure of Bufo bufo. As concentration of herbicide butachlor and time of dyeing poison increase, the coefficient of liver becomes augmented, and hepatic structure becomes augmented and autolyzed. Conclusion: Herbicide butachlor can change the hepatic modality and structure of Bufo bufo, suggesting environmental protection should be considered when herbicide is used.%观察除草剂丁草胺对蟾蜍肝脏形态学和组织学的影响,探讨除草剂丁草胺对蟾蜍肝脏的毒性作用.将中华大蟾蜍随机分为对照组、稻田组、稻田5倍组和稻田10倍组,染毒剂量分别为5、10、30 ml/L,每组15只,分别放入盛有经曝气的自来水和试验用液的实验桶内,溶液的量为浸没1/2蟾蜍体积,分别在染毒后3、6、9d,从各组随机取蟾蜍5只,解剖观察其肝脏的形态,测量肝系数;应用石蜡切片,HE染色,观察除草剂丁草胺对蟾蜍肝脏组织结构的影响.结果:除草剂丁草胺的染毒时间和浓度均可影响蟾蜍肝脏的组织结构.随着除草剂丁草胺浓度的增加和染毒时间的递增,肝系

  11. On The Identity Of Some Toads Of The Genus Bufo From Ecuador, With Additional Remarks On Andinophryne Colomai Hoogmoed, 1985 (Amphibia: Anura: Bufonidae).

    NARCIS (Netherlands)

    Hoogmoed, M.S.

    1989-01-01

    Study of the type specimens of B. caeruleostictus Günther, 1859 and B. chanchanensis Fowler, 1913, and of fresh material showed that B. chanchanensis is a junior subjective synonym of B. caeruleostictus. Probably it is a member of the B. guttatus group. B. caeruleocellatus Fowler, 1913 is a junior s

  12. Travelling waves for the cane toads equation with bounded traits

    International Nuclear Information System (INIS)

    In this paper, we study propagation in a non-local reaction–diffusion–mutation model describing the invasion of cane toads in Australia (Phillips et al 2006 Nature 439 803). The population of toads is structured by a space variable and a phenotypical trait and the space diffusivity depends on the trait. We use a Schauder topological degree argument for the construction of some travelling wave solutions of the model. The speed c* of the wave is obtained after solving a suitable spectral problem in the trait variable. An eigenvector arising from this eigenvalue problem gives the flavour of the profile at the edge of the front. The major difficulty is to obtain uniform L∞ bounds despite the combination of non-local terms and a heterogeneous diffusivity. (paper)

  13. Travelling waves for the cane toads equation with bounded traits

    Science.gov (United States)

    Bouin, Emeric; Calvez, Vincent

    2014-09-01

    In this paper, we study propagation in a non-local reaction-diffusion-mutation model describing the invasion of cane toads in Australia (Phillips et al 2006 Nature 439 803). The population of toads is structured by a space variable and a phenotypical trait and the space diffusivity depends on the trait. We use a Schauder topological degree argument for the construction of some travelling wave solutions of the model. The speed c* of the wave is obtained after solving a suitable spectral problem in the trait variable. An eigenvector arising from this eigenvalue problem gives the flavour of the profile at the edge of the front. The major difficulty is to obtain uniform L∞ bounds despite the combination of non-local terms and a heterogeneous diffusivity.

  14. Isoflurane, sevoflurane and desflurane use in cane toads (Rhinella marina).

    Science.gov (United States)

    Morrison, Kaleigh E; Strahl-Heldreth, Danielle; Clark-Price, Stuart C

    2016-01-01

    Anaesthetic chamber concentrations of isoflurane, sevoflurane and desflurane that resulted in loss of righting reflex within 15 minutes in 50 per cent of toads (Rhinella marina) exposed (ED50-LRR<15MIN) were identified. The median and range ED50-LRR<15MIN was 1.4 (0.9-1.4) per cent for isoflurane, 1.75 (1.1-1.9) per cent for sevoflurane and 4.4 (4.3-5.5) per cent for desflurane. Subsequently, toads were exposed to 1.5 times the ED50-LRR<15MIN and times to loss and return of righting reflex were identified. All toads for all anaesthetics lost righting reflex. The median and range loss of righting reflex was 4:00 (3:00-5:30) minutes for isoflurane, 4:45 (3:30-7:00) minutes for sevoflurane, and 4:15 (4:00-5:30) minutes for desflurane and was not different between anaesthetics. Time to return of righting reflex was 175 (123-211) minutes for isoflurane, 192 (116-383) minutes for sevoflurane and 74 (52-220) minutes for desflurane. Time to return of righting reflex was significantly shorter for desflurane compared with isoflurane or sevoflurane. The use of isoflurane, sevoflurane or desflurane can be used to provide immobilisation to cane toads and potentially other anurans. Induction times are likely similar when using an anaesthetic chamber to provide anaesthesia. However recovery time may take twice as long when utilising isoflurane or sevoflurane over desflurane. PMID:27651914

  15. Habitat use and movement of the endangered Arroyo Toad (Anaxyrus californicus) in coastal southern California

    Science.gov (United States)

    Gallegos, Elizabeth; Lyren, Lisa M.; Lovich, Robert E.; Mitrovich, Milan J.; Fisher, Robert N.

    2011-01-01

    Information on the habitat use and movement patterns of Arroyo Toads (Anaxyrus californicus) is limited. The temporal and spatial characteristics of terrestrial habitat use, especially as it relates to upland use in coastal areas of the species' range, are poorly understood. We present analyses of radiotelemetry data from 40 individual adult toads tracked at a single site in coastal southern California from March through November of 2004. We quantify adult Arroyo Toad habitat use and movements and interpret results in the context of their life history. We show concentrated activity by both male and female toads along stream terraces during and after breeding, and, although our fall sample size is low, the continued presence of adult toads in the floodplain through the late fall. Adult toads used open sandy flats with sparse vegetation. Home-range size and movement frequency varied as a function of body mass. Observed spatial patterns of movement and habitat use both during and outside of the breeding period as well as available climatological data suggest that overwintering of toads in floodplain habitats of near-coastal areas of southern California may be more common than previously considered. If adult toads are not migrating out of the floodplain at the close of the breeding season but instead overwinter on stream terraces in near-coastal areas, then current management practices that assume toad absence from floodplain habitats may be leaving adult toads over-wintering on stream terraces vulnerable to human disturbance during a time of year when Arroyo Toad mortality is potentially highest.

  16. Exposure and post-exposure effects of endosulfan on Bufo bufo tadpoles: morpho-histological and ultrastructural study on epidermis and iNOS localization.

    Science.gov (United States)

    Bernabò, Ilaria; Guardia, Antonello; La Russa, Daniele; Madeo, Giuseppe; Tripepi, Sandro; Brunelli, Elvira

    2013-10-15

    Endosulfan is a persistent organic pollutant (POP) that has lethal and sublethal effects on non-target organisms, including amphibians. In a laboratory study, we investigated direct and post-exposure effects of endosulfan on Bufo bufo tadpoles. For this purpose we exposed the tadpoles to a single short-term contamination event (96 h) at an environmentally-realistic concentration (200 μg endosulfan/L). This was followed by a recovery period of 10 days when the experimental animals were kept in pesticide-free water. The endpoints were assessed in terms of mortality, incidence of deformity, effects on behavior, and the morpho-functional features of the epidermis. We found that a short-term exposure to the tested concentration of endosulfan did not cause mortality but induced severe sublethal effects, such as hyperactivity, convulsions, and axis malformations. Following relocation to a pesticide-free environment, we noted two types of response within the experimental sample, in terms of morphological and behavioral traits. Moreover, by using both ultrastructural and a morpho-functional approach, we found that a short-term exposure to endosulfan negatively affected the amphibian epidermis. We also observed several histo-pathological alterations: increased mucous secretion, an increase in intercellular spaces and extensive cell degeneration, together with the induction of an inducible isoform of nitric oxide synthase (iNOS). Following the post-exposure period, we found large areas of epidermis in which degeneration phenomena were moderate or absent, as well as a further increase in iNOS immunoreactivity. Thus, after 10 days in a free-pesticide environment, the larval epidermis was able to partially replace elements that had been compromised due to a physiological and/or a pathological response to the pesticide. These results highlight the need for both exposure and post-exposure experiments, when attempting to assess pollutant effects.

  17. Humoral immune alterations caused by lead: studies on an adult toad model Alteraciones inmunes humorales causadas por plomo: estudios en un modelo de sapo adulto

    Directory of Open Access Journals (Sweden)

    Carolina E. Rosenberg

    2007-07-01

    Full Text Available There is evidence that environmental metal levels affect the immune function. In the particular case of the impact of heavy metals, information available suggests that the immune system is a target for low-dose Pb exposure. Among vertebrates it was shown that amphibians are capable of forming antibodies against a variety of antigens, causing several responses such as anaphylactic response and rejecting grafts. In this study, the production of antibodies was assessed against sheep red blood cells (SRBC in the anuran Bufo arenarum after six weekly injections of sublethal doses of lead (50 mg.kg-1, as lead acetate. Natural antibodies (natural heteroagglutinins were also quantified against SRBC. Both assessments were carried out employing an ELISA method developed to this end, measuring absorbance (A. For natural anti-SRBC antibodies in both control (C and Pb treated (T toads, there was a non significant tendency to increase the initial absorbances (C initial: 0.69±0.39 A; T initial: 0.54±0.30 A, relative to those registered at the end of the experiments (C final: 0.89±0.49 A; T final: 0.76±0.31A; the T/C ratios also did not show changes. The only significant difference was found between initial and final samples from lead-treated toads (pExiste evidencia de que los niveles de metal ambientales afectan la función inmune. En el caso particular del impacto de metales pesados, la información disponible sugiere que el sistema inmune es un blanco para la exposición a bajas dosis de Pb. Entre los vertebrados, se ha mostrado que los anfibios son capaces de formar anticuerpos contra una variedad de antígenos, que causan diversas respuestas, tales como respuesta anafiláctica y rechazo de injertos. En este estudio, la producción de anticuerpos fue evaluada contra eritrocitos de oveja (EO en el anuro Bufo arenarum, luego de seis inyecciones semanales de dosis subletales de plomo (50 mg.kg-1, como acetato de Pb. Los anticuerpos naturales

  18. Adrenocortical function in cane toads from different environments.

    Science.gov (United States)

    Hernández, Sandra E; Sernia, Conrad; Bradley, Adrian J

    2016-05-01

    The adrenocortical function of cane toads (Rhinella marina) exposed to different experimental procedures, as well as captured from different environments, was assessed by challenging the hypothalamic-pituitary-adrenal (HPA) axis. It was found that restriction stress as well as cannulation increased plasma corticosterone (B) levels for up to 12h. A single dose of dexamethasone (DEX 2mg/kg) significantly reduced B levels demonstrating its potential for use in the evaluation of the HPA axis in amphibia. We also demonstrate that 0.05 IU/g BW (im) of synthetic adrenocorticotropic hormone (ACTH) significantly increased plasma B levels in cane toads. Changes in size area of the cortical cells were positively associated with total levels of B after ACTH administration. We also found differences in adrenal activity between populations. This was assessed by a DEX-ACTH test. The animals captured from the field and maintained in captivity for one year at the animal house (AH) present the highest levels of total and free B after ACTH administration. We also found that animals from the front line of dispersion in Western Australia (WA) present the weakest adrenal response to a DEX-ACTH test. The animals categorized as long established in Queensland Australia (QL), and native in Mexico (MX), do not shown a marked difference in the HPA activity. Finally we found that in response to ACTH administration, females reach significantly higher levels of plasma B than males. For the first time the adrenocortical response in cane toads exposed to different experimental procedures, as well as from different populations was assessed systematically. PMID:26877241

  19. Ion transport by mitochondria-rich cells in toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Ussing, H H; Spring, K R

    1987-01-01

    The optical sectioning video imaging technique was used for measurements of the volume of mitochondria-rich (m.r.) cells of the isolated epithelium of toad skin. Under short-circuit conditions, cell volume decreased by about 14% in response to bilateral exposure to Cl-free (gluconate substitution......) solutions, apical exposure to a sodium-free solution, or to amiloride. Serosal exposure to ouabain resulted in a large increase in volume, which could be prevented either by the simultaneous application of amiloride in the apical solution or by the exposure of the epithelium to bilateral Cl-free solutions...

  20. Cane toads lack physiological enhancements for dispersal at the invasive front in Northern Australia

    Directory of Open Access Journals (Sweden)

    Christopher R. Tracy

    2011-11-01

    Many invasive species have evolved behavioural and morphological characteristics that facilitate their dispersal into new areas, but it is unclear how selection on this level of the phenotype filters through to the underlying physiology. Cane toads have been dispersing westward across northern tropical Australia for more than 70 years. Previous studies of cane toads at the invasive front have identified several behavioural, morphological and locomotory characteristics that have evolved to facilitate dispersal of toads. We assessed a range of physiological characteristics associated with locomotory abilities in toads from the long-established, east coast of Australia, from the invasive front, and from a site in between these locations. We measured time to exhaustion and respiratory gases of toads exercising on a treadmill, time to recovery from exhaustion, blood properties (lactate, haematocrit, haemoglobin, red blood cell count, blood cell volume, and muscle properties associated with locomotion (activities of the enzymes citrate synthase and lactate dehydrogenase, and pH buffering capacity. None of the measured physiological parameters supported the hypothesis that toads from the invasive front possess physiological adaptations that facilitate dispersal compared to toads from areas colonised in the past. The strongest difference among the three groups of toads, time to exhaustion, showed exactly the opposite trend; toads from the long-established populations in the east coast had the longest time to exhaustion. Successful colonisers can employ many characteristics to facilitate their dispersal, so the extent to which behaviour, morphology and physiology co-evolve remains an interesting question. However, in the present case at least, behavioural adaptations do not appear to have altered the organism's underlying physiology.

  1. The identity of the South African toad Sclerophrys capensis Tschudi, 1838 (Amphibia, Anura).

    Science.gov (United States)

    Ohler, Annemarie; Dubois, Alain

    2016-01-01

    The toad species Sclerophrys capensis Tschudi, 1838 was erected for a single specimen from South Africa which has never been properly studied and allocated to a known species. A morphometrical and morphological analysis of this specimen and its comparison with 75 toad specimens referred to five South African toad species allowed to allocate this specimen to the species currently known as Amietophrynus rangeri. In consequence, the nomen Sclerophrys must replace Amietophrynus as the valid nomen of the genus, and capensis as the valid nomen of the species. This work stresses the usefulness of natural history collections for solving taxonomic and nomenclatural problems.

  2. Lankesterella poeppigii n. sp. (Apicomplexa, Lankesterellidae from Bufo poeppigii (Tschudi, 1845 from Peru

    Directory of Open Access Journals (Sweden)

    Ilan Paperna

    2011-07-01

    Full Text Available Lankesterella poeppigii n. sp. is described from Bufo poeppigii (Tschudi, 1845 from Peru. Merogony and oogony occur in the capillary endothelium and the macrophages in the liver, spleen and kidneys. Meronts are oval, 25,2–29,4 x 15,7–16,8 μm in size and yield 35–46 merozoites. Oocysts are 26,3–29,4 x 15,1–17,6 μm in size; sporozoites 9,2-9,8 x 4,2–5,0 μm in size, assemble in macrophages. Released 8,7–9,8 x 2,8–3,1 μm sporozoites enter erythrocytes. L. poeppigii is compared with Lankesterella petiti Lainson & Paperna, 1995 infecting Bufo marinus (Linnaeus, 1758 in Brazil. The above mentioned specific characters, added to differences in hosts and geographical location warrant the description of Lankesterella poeppigii from B. poeppigii as a new species.

  3. Sensory feedback and coordinating asymmetrical landing in toads.

    Science.gov (United States)

    Cox, S M; Gillis, Gary B

    2016-06-01

    Coordinated landing requires anticipating the timing and magnitude of impact, which in turn requires sensory input. To better understand how cane toads, well known for coordinated landing, prioritize visual versus vestibular feedback during hopping, we recorded forelimb joint angle patterns and electromyographic data from five animals hopping under two conditions that were designed to force animals to land with one forelimb well before the other. In one condition, landing asymmetry was due to mid-air rolling, created by an unstable takeoff surface. In this condition, visual, vestibular and proprioceptive information could be used to predict asymmetric landing. In the other, animals took off normally, but landed asymmetrically because of a sloped landing surface. In this condition, sensory feedback provided conflicting information, and only visual feedback could appropriately predict the asymmetrical landing. During the roll treatment, when all sensory feedback could be used to predict an asymmetrical landing, pre-landing forelimb muscle activity and movement began earlier in the limb that landed first. However, no such asymmetries in forelimb preparation were apparent during hops onto sloped landings when only visual information could be used to predict landing asymmetry. These data suggest that toads prioritize vestibular or proprioceptive information over visual feedback to coordinate landing. PMID:27247440

  4. Sensory feedback and coordinating asymmetrical landing in toads.

    Science.gov (United States)

    Cox, S M; Gillis, Gary B

    2016-06-01

    Coordinated landing requires anticipating the timing and magnitude of impact, which in turn requires sensory input. To better understand how cane toads, well known for coordinated landing, prioritize visual versus vestibular feedback during hopping, we recorded forelimb joint angle patterns and electromyographic data from five animals hopping under two conditions that were designed to force animals to land with one forelimb well before the other. In one condition, landing asymmetry was due to mid-air rolling, created by an unstable takeoff surface. In this condition, visual, vestibular and proprioceptive information could be used to predict asymmetric landing. In the other, animals took off normally, but landed asymmetrically because of a sloped landing surface. In this condition, sensory feedback provided conflicting information, and only visual feedback could appropriately predict the asymmetrical landing. During the roll treatment, when all sensory feedback could be used to predict an asymmetrical landing, pre-landing forelimb muscle activity and movement began earlier in the limb that landed first. However, no such asymmetries in forelimb preparation were apparent during hops onto sloped landings when only visual information could be used to predict landing asymmetry. These data suggest that toads prioritize vestibular or proprioceptive information over visual feedback to coordinate landing.

  5. Molecular characterization of MHC class II in the Australian invasive cane toad reveals multiple splice variants.

    Science.gov (United States)

    Lillie, Mette; Cui, Jian; Shine, Richard; Belov, Katherine

    2016-07-01

    The cane toad has gained notoriety for its invasion across the Australian landscape, with significant impacts on the native Australian fauna. The invasion has accelerated over time, with invading cane toads adapted for highly dispersive traits. This, however, has come at the cost of the immune system, with lower investment in some immune functions. To investigate the cane toad's immunogenetics, we characterized four major histocompatibility complex (MHC) class IIA and three MHC class IIB loci. Preliminary observations suggest very low allelic diversity at all loci. We also observed various splice isoforms. One isoform seen at one class IIA and two class IIB loci was missing exon 2, which is essential to peptide binding and presentation. The other isoform, observed at a class IIA locus, is likely to be a soluble MHC product. These results may suggest a significant role of alternative splicing of MHC loci in the Australian cane toad. PMID:27233954

  6. Towed Optical Assessment Device (TOAD) Data to Support Benthic Habitat Mapping since 2001

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Optical validation data were collected using a Tethered Optical Assessment Device (TOAD), an underwater sled equipped with an underwater digital video camera and...

  7. Vascular aspects of water uptake mechanisms in the toad skin: perfusion, diffusion, confusion

    DEFF Research Database (Denmark)

    Willumsen, Niels; Viborg, Arne L; Hillyard, Stanley D

    2007-01-01

    Blood cell flow (BCF) in the water absorbing "seat patch" region of toad skin was measured with laser Doppler flow cytometry. BCF of dehydrated toads increased by a factor of 6-8 when water contact was made and declined gradually as toads rehydrated. Water absorption was initially stimulated...... and declined in parallel with BCF. Water absorption measured during the initial rehydration period did not correlate with BCF and hydrated toads injected with AVT increased water absorption without an increase in BCF indicating the lack of an obligate relation between blood flow and water absorption...... coupling explains the greater absorption from dilute salt solutions. Rehydration from 10 mM CaCl2 was stimulated above that of DI water by a similar degree as with 50 mM NaCl suggesting the anion might control water permeability of the skin....

  8. Helmintos parásitos de anfibios: Dos Especies de Nemátodos parásitos de Bufo spinulosus trifolium (Tschudi)

    OpenAIRE

    Asucena Naupay

    2014-01-01

    En el presente trabajo sobre los helmintos que parasitan a Bufo spinulosus trifolium (Tschudi) de la localidad de Huánuco, se presentan dos especies conocidas para la ciencia pero una de ellas nueva para el Perú.

  9. Variación ontogenética en la palatibilidad de los renacuajos de Bufo spinulosus papillosus Philippi, 1902 (Anura: Bufonidae

    Directory of Open Access Journals (Sweden)

    Jara, Fabián Gastón

    2006-03-01

    Full Text Available Se evaluó la variación ontogenética de la palatabilidad en Bufo spinulosus papillosus expuestos a larvas del odonato Rhionaeshna variegata (Odonata, Aeshnidae. Los renacuajos fueron agrupados en cuatro categorías de desarrollo y fueron expuestos a la depredación directa determinándose el número de renacuajos consumidos al finalizar los experimentos. Bufo spinulosus papillosus no fue palatable en los primeros estadios del desarrollo (categorías I, estadios 24-26 y categoría II, estadios 32-34, mientras que los estadios de las categoría III (estadios 38-40 y categoría IV (estadios 42-45 fueron progresivamente palatables. Se observó un comportamiento de rechazo por parte de los depredadores luego de la captura de renacuajos de las categorías I y II. El patrón de palatabilidad encontrado en Bufo spinulosus papillosus difiere del observado en otras especies relacionadas del género Bufo (Brodie y Formanowicz, 1987; Kehr y Schnack, 1991; Lawler y Hero, 1997. We evaluated the ontogenetic variation in the palatability of Bufo spinulosus papillosus tadpoles exposed to odonate larvae of Rhionaeshna variegata (Odonata, Aeshnidae. We exposed tadpoles to direct predation and determined the number of consumed tadpoles in four developmental categories. Bufo spinulosus papillosus tadpoles of categories I (stages 24-26 and II (stages 32-34 were unpalatable, while categories III (stages 38-40 and IV (stages 42-45 were progressively palatable. We observed a post-capture rejection behavior when they caught unpalatable tadpoles in categories I and II. The palatability pattern observed in Bufo spinulosus papillosus was different from related Bufo species (Brodie and Formanowicz, 1987; Kehr and Schnack, 1991; Lawler and Hero, 1997.

  10. Biotic Resistance to an Alien Amphibian: Larval Competition between Japanese Frogs and Invasive Cane Toads

    Science.gov (United States)

    2016-01-01

    Understanding negative effects of native species on introduced taxa may suggest novel ways to control the invasive species by enhancing such effects. Previous studies have reported that the larvae of invasive cane toads (Rhinella marina) are suppressed by competition with the larvae of native anurans in Australia, but not in North America. We conducted laboratory trials to measure the effect of exposure to the larvae of Japanese frogs (Microhyla ornata, Fejervarya sakishimensis, Rhacophorus owstoni) on rates of survival, growth and development of cane toad tadpoles in Ishigaki Island, in southern Japan. Survival rates were not affected by native species, but competition with Dicroglossids and Rhacophorids (but not Microhylids) strongly reduced rates of growth and development in the tadpoles of cane toads. Dicroglossid tadpoles also reduced the body condition to toad tadpoles in addition to effects on SVL and mass. Encouraging populations of native frogs in toad-invaded areas of Japan thus may help to reduce the numbers of invasive cane toads. PMID:27253973

  11. CEPF Western Ghats Special Series: Description of tadpole stages of the Malabar Tree Toad Pedostibes tuberculosis Gunther, 1875 (Anura: Bufonidae

    Directory of Open Access Journals (Sweden)

    K.P. Dinesh

    2014-10-01

    Full Text Available Pedostibes tuberculosus, the Malabar tree toad, was described 137 years ago from the Malabar region (now the coastal parts of Kerala of the Western Ghats. Since the description of this arboreal toad, not much information is available on the natural history, breeding habits and life cycle except for its description, range of distribution and advertisement call details. In the present account, the tadpole stages of this toad from Gosner tadpole Stage 21 to 45 are presented and the phytotelmatic mode of life of this toad has been confirmed by locating the tadpoles within the Ochlandra reed culm.

  12. The All Optical New Universal Gate Using TOAD

    Directory of Open Access Journals (Sweden)

    Goutam Kumar Maity

    2014-06-01

    Full Text Available Since the seventies of the past century the reversible logic has originated as an unconventional form of computing. It is new relatively in the area of extensive applications in quantum computing, low power CMOS, DNA computing, digital signal processing (DSP, nanotechnology, communication, optical computing, computer graphics, bio information, etc .Here we present and configure a new TAND gate in all-optical domain and also in this paper we have explained their principle of operations and used a theoretical model to fulfil this task, finally supporting through numerical simulations. In the field of ultra-fast all-optical signal processing Terahertz Optical Asymmetric Demultiplexer (TOAD, semiconductor optical amplifier (SOA-based, has an important function. The different logical (composing of Boolean function operations can be executed by designed circuits with TAND gate in the domain of universal logic-based information processing.

  13. Oswaldocruzia venezuelensis sp. n. (Nematoda:Trichostrongylina, Molineoidea), a parasite of Bufo marinus from Venezuela.

    Science.gov (United States)

    Ben Slimane, B; Guerrero, R; Durette-Desset, M C

    1996-01-01

    A new species of Oswaldocruzia Travassos, 1917, a parasite of Bufo marinus L. from Venezuela, is described. Like most Neotropical Oswaldocruzia, Oswaldocruzia venezuelensis sp. n. is characterized by spicules with three principal branches: blade, shoe and fork, and by a division of the fork within the distal third of the spicule length. O. vaucheri Ben Slimane et Durette-Desset, 1993 is the most closely related species due to its caudal bursa of type II and its cervical alae of the same shape but it differs in the following characters: the position of the papillae of rays 4 situated nearer the papillae of rays 3 rather than rays 5, a higher percentage of the ridges in the oesophageal region, the cervical alae three times longer and sharp and the spicular fork divided less deeply.

  14. Molecular cloning and characterization of cystatin, a cysteine protease inhibitor, from bufo melanostictus.

    Science.gov (United States)

    Liu, Wa; Ji, Senlin; Zhang, A-Mei; Han, Qinqin; Feng, Yue; Song, Yuzhu

    2013-01-01

    Cystatins are efficient inhibitors of papain-like cysteine proteinases, and they serve various important physiological functions. In this study, a novel cystatin, Cystatin-X, was cloned from a cDNA library of the skin of Bufo melanostictus. The single nonglycosylated polypeptide chain of Cystatin-X consisted of 102 amino acid residues, including seven cysteines. Evolutionary analysis indicated that Cystatin-X can be grouped with family 1 cystatins. It contains cystatin-conserved motifs known to interact with the active site of cysteine proteinases. Recombinant Cystatin-X expressed and purified from Escherichia coli exhibited obvious inhibitory activity against cathepsin B. rCystatin-X at a concentration of 8 µM inhibited nearly 80% of cathepsin B activity within 15 s, and about 90% of cathepsin B activity within 15 min. The Cystatin-X identified in this study can play an important role in host immunity and in the medical effect of B. melanostictus.

  15. Influence of demography and environment on persistence in toad populations

    Science.gov (United States)

    Lambert, Brad A.; Schorr, Robert A.; Schneider, Scott C.; Muths, Erin L.

    2016-01-01

    Effective conservation of rare species requires an understanding of how potential threats affect population dynamics. Unfortunately, information about population demographics prior to threats (i.e., baseline data) is lacking for many species. Perturbations, caused by climate change, disease, or other stressors can lead to population declines and heightened conservation concerns. Boreal toads (Anaxyrus boreas boreas) have undergone rangewide declines due mostly to the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd), with only a few sizable populations remaining in the southern Rocky Mountains, USA, that are disease-free. Despite the apparent region-wide occurrence of Bd, our focal populations in central Colorado were disease free over a 14-year capture-mark-recapture study until the recent discovery of Bd at one of the sites. We used recapture data and the Pradel reverse-time model to assess the influence of environmental and site-specific conditions on survival and recruitment. We then forecast changes in the toad populations with 2 growth models; one using an average lambda value to initiate the projection, and one using the most recent value to capture potential effects of the incursion of disease into the system. Adult survival was consistently high at the 3 sites, whereas recruitment was more variable and markedly low at 1 site. We found that active season moisture, active season length, and breeding shallows were important factors in estimating recruitment. Population growth models indicated a slight increase at 1 site but decreasing trends at the 2 other sites, possibly influenced by low recruitment. Insight into declining species management can be gained from information on survival and recruitment and how site-specific environmental factors influence these demographic parameters. Our data are particularly useful because they provide baseline data on demographics in populations before a disease outbreak and enhance our ability to detect changes

  16. Alimentación y fecundidad de Bufo variegatus (Anura: Bufonidae en Santa Cruz, Argentina

    Directory of Open Access Journals (Sweden)

    Rappi, Guillermina E.

    2000-04-01

    Full Text Available Se describe la alimentación de una población de Bufo variegatus procedente de la región de Lago del Desierto, provincia de Santa Cruz, Argentina. De los 11 ítems presa identificados, los más consumidos por los adultos (tanto machos como hembras fueron los coleópteros. En los machos la segunda categoría presa mas importante en la contribución a la dieta fueron los ácaros, mientras que en las hembras las hormigas y las larvas de insectos siguieron en importancia al consumo de coleópteros. En los especímenes juveniles, los ácaros fueron las presas más consumidas, quedando los coleópteros en segundo lugar en importancia relativa. Se demuestra la existencia de una correlación positiva significativa entre el volumen de las presas y el tamaño del depredador. Se aportan datos referentes a la fecundidad de B. variegatus y se comprueba la ausencia de correlación entre el tamaño de las hembras grávidas y el número de óvulos maduros. The diet of a population of Bufo variegatus from the region of Lago del Desierto, Santa Cruz province, Argentina, is described. Of the 11 prey items identified, Coleoptera was the most consumed prey both for males and females. In males, the second most important prey was Acarii, while in females they were the ants and insect larvae. Acarii was the most consumed prey for juveniles, followed by Coleoptera. A significant positive correlation was found between prey volume and predator body size. Fecundity information for B. variegwus is given, and a lack of correlation between snout-vent length of mature females and ovarian egg complement is demonstrated.

  17. Dehydration hardly slows hopping toads (Rhinella granulosa) from xeric and mesic environments.

    Science.gov (United States)

    Prates, Ivan; Angilleta, Michael J; Wilson, Robbie S; Niehaus, Amanda C; Navas, Carlos A

    2013-01-01

    The locomotor capacity of amphibians depends strongly on temperature and hydration. Understanding the potential interactions between these variables remains an important challenge because temperature and water availability covary strongly in natural environments. We explored the effects of temperature and hydration on the hopping speeds of Rhinella granulosa, a small toad from the semiarid Caatinga and the Atlantic Rain Forest in Brazil. We asked whether thermal and hydric states interact to determine performance and whether toads from the Caatinga differ from their conspecifics from the Atlantic Forest. Both dehydration and cooling impaired hopping speed, but effects were independent of one another. In comparison to performances of other anurans, the performance of R. granulosa was far less sensitive to dehydration. Consequently, dehydrated members of this species may be able to sustain performance through high body temperatures, which agrees with the exceptional heat tolerance of this species. Surprisingly, toads from both the Caatinga and the Atlantic Forest were relatively insensitive to dehydration. This observation suggests that migration or gene flow between toads from the forest and those from a drier region occurred or that toads from a dry region colonized the forest secondarily. PMID:23799839

  18. Contribution to the study of immune hemolysis by toad complement

    Directory of Open Access Journals (Sweden)

    Marisa Gennari

    1982-09-01

    Full Text Available EA (sheep erythrocytes carrying rabbit antibody are lysed by toad complement under optimal conditions which include a low concentration of cells (1.54 x 10*8/ml, a low temperature of incubation (30°C and the same amounts of Ca++ and Mg++ as required for the titration of guinea-pig complement. Kinetic studies of the role of cations mentioned above in immune lysis by toad C have disclosed a fundamental difference as compared to guinea-pig C. In a limited complement system, the lysis by amphibian C is completely blocked by EDTA, even when the chelating agent is added as late as 15 minutes after zero-time. Inhibition by EGTA is only partial and the findings suggest that Mg++ is required not only at the beginning, but also at late stages of the lytic process. It has been speculated that the activation of amphibian complement proceeds mainly by the alternative pathway.EA (eritrócitos de carneiro, sensibilizados com anticorpos de coelho são lisados por complemento de sapo em condições ótimas, que consistem no uso de uma baixa concentração de células (1.54 x 10*8/ml, incubação a baixa temperatura (30°C e as mesmas quantidades de Ca++ e de Mg++, requeridas para a titulação da atividade hemolítica do complemento de cobaia. Estudos cinéticos do efeito dos cátions mencionados acima na imune-lise produzida pelo complemento de sapo revelam uma diferença fundamental com relação ao complemento de cobaía. Num sistema limitado pela quantidade de complemento, a lise pelo C de anfíbio é totalmente bloqueada por EDTA, mesmo quando a adição do agente quelante é feita após 15 minutos, ao passo que com EGTA o bloqueio é apenas parcial. Os achados experimentais sugerem que Mg++ seja requerido não apenas no estágio inicial, mas também em estágios tardios do processo lítico e permitem especular que a ativação do complemento de anfíbio se processa predominantemente pela via alternativa.

  19. Thermal ecology of the post-metamorphic Andean toad (Rhinella spinulosa) at elevation in the monte desert, Argentina.

    Science.gov (United States)

    Sanabria, Eduardo A; Rodríguez, César Y; Vergara, Cristina; Ontivero, Emanuel; Banchig, Mariana; Navas, Ana L; Herrera-Morata, Mario A; Quiroga, Lorena B

    2015-08-01

    Rhinella spinulosa is an anuran toad species distributed latitudinal and altitudinal (1200-5000m) from Peru to Argentina, inhabiting mountain valleys in the Andes. Considering the broad range of habitats where they live, it is important to understand the thermal physiological mechanisms, thermal tolerances and physiological adaptations for surviving in rigorous environments. We investigated the thermal parameters (field body temperature, selected body temperature, locomotor performance in field and laboratory conditions, and thermal extremes) during diurnal activity for a population of juvenile, post-metamorphosed toads (Rhinella spinulosa) from the Monte Desert of San Juan, Argentina. Post-metamorphic toads are active from approximately 1100-1900 (in contrast to nocturnal adult toads). Our findings show that these toads have a wide thermal tolerance range, ranging from a critical thermal maximum of 36.9°C to crystallization temperatures below 0°C. During their active period, toads always showed suboptimal thermal conditions for locomotion. Despite the suboptimal condition for the locomotion, diurnal activity is likely to confer thermal advantages, allowing them to search for food and increase digestion and growth rates. We also found that the toads are capable of super-cooling, which prevents mortality from freezing when the environmental temperatures drop below 0°C. The environmental temperatures are below zero at night, when toads are inactive and take refuge under rocks. In summary, this toad population demonstrates high thermal plasticity, as shown by a relatively high level of activity sustained over a wide range of ambient temperature (~35°C). These thermal adaptations allow this species of juvenile toads to inhabit a wide range of altitudes and latitudes.

  20. Optimizing the performance of TOAD by changing the wavelength and power of control pulse

    Institute of Scientific and Technical Information of China (English)

    Liangsheng Wen(温亮生); Peng Zuo(左鹏); Jian Wu(伍剑); Jintong Lin(林金桐)

    2003-01-01

    The performance of terahertz optical asymmetric demultiplexer (TOAD) has been studied by modelling the semiconductor optical amplifier (SOA) in which the intraband effects had been taken into account.Numerical results are coincident with the experiment results. We interpret why there are three peaks in the switching window, which has never been reported before. In addition, we put forward the definition of the flatness of the switching window of TOAD for the first time By analysing the different phase of clockwise and counter clockwise signal pulse changed by SOA, appropriate peak power of control pulse and wavelength of signal and control pulse have been calculated in order to obtain large output power and flat switching window of TOAD.

  1. Anticipatory motor patterns limit muscle stretch during landing in toads.

    Science.gov (United States)

    Azizi, Emanuel; Abbott, Emily M

    2013-02-23

    To safely land after a jump or hop, muscles must be actively stretched to dissipate mechanical energy. Muscles that dissipate energy can be damaged if stretched to long lengths. The likelihood of damage may be mitigated by the nervous system, if anticipatory activation of muscles prior to impact alters the muscle's operating length. Anticipatory motor recruitment is well established in landing studies and motor patterns have been shown to be modulated based on the perceived magnitude of the impact. In this study, we examine whether motor recruitment in anticipation of landing can serve a protective function by limiting maximum muscle length during a landing event. We use the anconeus muscle of toads, a landing muscle whose recruitment is modulated in anticipation of landing. We combine in vivo measurements of muscle length during landing with in vitro characterization of the force-length curve to determine the muscle's operating length. We show that muscle shortening prior to impact increases with increasing hop distance. This initial increase in muscle shortening functions to accommodate the larger stretches required when landing after long hops. These predictive motor strategies may function to reduce stretch-induced muscle damage by constraining maximum muscle length, despite variation in the magnitude of impact. PMID:23256184

  2. Multiple paternity in a viviparous toad with internal fertilisation

    Science.gov (United States)

    Sandberger-Loua, Laura; Feldhaar, Heike; Jehle, Robert; Rödel, Mark-Oliver

    2016-08-01

    Anurans are renowned for a high diversity of reproductive modes, but less than 1 % of species exhibit internal fertilisation followed by viviparity. In the live-bearing West African Nimba toad ( Nimbaphrynoides occidentalis), females produce yolk-poor eggs and internally nourish their young after fertilisation. Birth of fully developed juveniles takes place after 9 months. In the present study, we used genetic markers (eight microsatellite loci) to assign the paternity of litters of 12 females comprising on average 9.7 juveniles. In 9 out of 12 families (75 %), a single sire was sufficient; in three families (25 %), more than one sire was necessary to explain the observed genotypes in each family. These findings are backed up with field observations of male resource defence (underground cavities in which mating takes place) as well as coercive mating attempts, suggesting that the observed moderate level of multiple paternity in a species without distinct sperm storage organs is governed by a balance of female mate choice and male reproductive strategies.

  3. Effect of stretch on passive transport in toad urinary bladder.

    Science.gov (United States)

    Lief, P D; Mutz, B F; Bank, N

    1976-06-01

    In order to gain further information about the effect of stretch on the urinary bladder of the toad, transepithelial movement of radioactive sucrose, chloride, and urea was measured across bladder sacs during acute changes in the internal volume. Short-circuit current (SCC) and total tissue conductance (Kt) were also measured in each experiment. It was found that sudden large increases or smaller graded increases in volume resulted in a consistent fall in the tracer permeability (P*) of all three isotopes. However, this fall was due entirely to the larger area term in the calculation of P* rather than any real change in isotope movement. When total diffusion (TD) of each isotope was calculated by a method that eliminated the changes in surface area, it was apparent that stretch produced no significant effects on the transepithelial movement of any of these three molecules. Large stretch also resulted in parallel increases in SCC and Kt in most bladders. We conclude from these observations that the intercellular pathway for sucrose and chloride and the transcellular pathway for urea are unaltered by degrees of stretch that enhance SCC and sodium transport. By inference, the observed increases in Kt appear to represent changes in specific active pathway conductance (Ka), and may relate importantly to the changes in sodium transport. PMID:820207

  4. Nux Vomica 200 CH reduced acute hypnotic effect of alcohol in young toads

    OpenAIRE

    Nirmal Sukul; Arniban Sukul; Indrani Chakraborty

    2012-01-01

    Potentized Nux Vomica has been reported to produce antialcoholic effect in mice, rats and toads. The effect relates to consumption of alcohol and alcohol-induced loss of righting reflex (RR). RR’s maintain normal erect posture of an animal and are centrally controlled in the midbrain. In the present study young toads, Duttaphrynus melanostictus were first treated with Nux vomica 200 CH and then partially immersed in 209 mM ethanol solution in such a way that their head remained above t...

  5. Descripción de dos renacuajos y una clave para las larvas conocidas del grupo Bufo spinulosus (Anura: Bufonidae de Perú

    Directory of Open Access Journals (Sweden)

    César Aguilar

    2013-06-01

    Full Text Available Se describen los renacuajos de Bufo arequipensis y Bufo cophotis. Ningún carácter externo examinado permite distinguir la larva de las especies nominales B. arequipensis, B. flavolineatus y B. trifolium. La larva de Bufo limensis se diferencia de las de B. flavolineatus y B. trifolium por presentar un espacio menor en la segunda fila anterior de dentículos labiales y una fórmula de dentículos labiales (LTRF igual a 2(2/3[1]. B. cophotis difiere de B. limensis, B. flavolineatus y B. trifolium por presentar la altura máxima de la cola en su extremo posterior, una coloración marrón oscura en el cuerpo y cola, y un LTRF igual a 2(2/3(1. Se proporciona una clave de identificación para las larvas conocidas del grupo spinulosus presentes en Perú.

  6. New regional record and notes on historical specimens of Gunther Toad Duttaphrynus hololius with comments on other southeastern Indian congeners

    Directory of Open Access Journals (Sweden)

    B. Srinivasulu

    2013-09-01

    Full Text Available We report on the finding of the Günther Toad Duttaphrynus hololius from Visakhapatnam and discuss aspects of its distribution based on our species distribution modeling. We also provide data on historically collected specimens and refine its intra-specific variation, provide an up-to-date chresonymy and comment on the validity of earlier reported diagnosis. Lastly, we remark on some misidentification-mediated dubious southern Indian records of another, related congener, the Marbled Toad D. stomaticus and correct some misallocations by referring them to another syntopic congener, the Dwarf Toad D. scaber.

  7. Immune response varies with rate of dispersal in invasive cane toads (Rhinella marina.

    Directory of Open Access Journals (Sweden)

    Gregory P Brown

    Full Text Available What level of immunocompetence should an animal maintain while undertaking long-distance dispersal? Immune function (surveillance and response might be down-regulated during prolonged physical exertion due to energy depletion, and/or to avoid autoimmune reactions arising from damaged tissue. On the other hand, heightened immune vigilance might be favored if the organism encounters novel pathogens as it enters novel environments. We assessed the links between immune defense and long-distance movement in a population of invasive cane toads (Rhinella marina in Australia. Toads were radio-tracked for seven days to measure their activity levels and were then captured and subjected to a suite of immune assays. Toads that moved further showed decreased bacteria-killing ability in their plasma and decreased phagocytic activity in their whole blood, but a heightened skin-swelling response to phytohemagglutinin. Baseline and post-stress corticosterone levels were unrelated to distance moved. Thus, long-distance movement in cane toads is associated with a dampened response in some systems and enhanced response in another. This pattern suggests that sustained activity is accompanied by trade-offs among immune components rather than an overall down or up-regulation. The finding that high mobility is accompanied by modification of the immune system has important implications for animal invasions.

  8. Etomidate anaesthesia by immersion in oriental fire-bellied toads (Bombina orientalis).

    Science.gov (United States)

    d'Ovidio, D; Spadavecchia, C; Angeli, G; Adami, C

    2015-10-01

    The objective of the present study was to evaluate the efficacy and the safety of etomidate anaesthesia by immersion technique in Bombina orientalis. The study comprised two phases. The first phase was carried out to identify the etomidate concentration capable of producing anaesthetic induction, as well as surgical anaesthesia, in the toads. The second phase was aimed at testing that concentration in eight additional animals. Etomidate administered via immersion at a concentration of 37.5 mg/L produced effective anaesthesia in oriental fire-bellied toads. The average duration of surgical anaesthesia was 20 min. All the toads enrolled in the study survived the anaesthesia and long-term complications did not occur. However, undesired side-effects, namely itching, myoclonus and prolonged recovery, were noticed during the perianaesthetic period. The authors concluded that etomidate anaesthesia by immersion, at a concentration of 37.5 mg/L, is suitable in oriental fire-bellied toads and produces anaesthesia of a depth and duration that is sufficient to allow the completion of various experimental procedures, without resulting in lethal complications. However, the occurrence of undesired side-effects opens a debate on the safety of this anaesthetic technique, and imposes the need for further investigation prior to proposing the latter for routine laboratory practice.

  9. ACTION OF PROGESTERONE ON THE DEPOLARIZATION OF THE MEMBRANE POTENTIAL IN TOAD OOCYTES INDUCED BY LEUCINE

    Institute of Scientific and Technical Information of China (English)

    WANGYu-Feng

    1989-01-01

    The depolarization of the membrane potential in toad oocytes induced by leucine was found in our previous experiment. In this paper, a possible action or progesterone in the process was further investigated. After oocytes had been incubated for 16 to 24 hours with

  10. Tetrodotoxin and its analogues in extracts from the toad Atelopus oxyrhynchus (family: Bufonidae).

    Science.gov (United States)

    Yotsu-Yamashita, M; Mebs, D; Yasumoto, T

    1992-11-01

    Tetrodotoxin and its analogues, 4-epitetrodotoxin and 4,9-anhydrotetrodotoxin, were detected in the toad Atelopus oxyrhynchus by HPLC analysis. The toxin and its analogues were still present in a specimen which lived 3.5 years in captivity. PMID:1336632

  11. The Effect of UV-B Radiation on Bufo arenarum Embryos Survival and Superoxide Dismutase Activity

    Directory of Open Access Journals (Sweden)

    O. Fridman

    2006-03-01

    Full Text Available The exposure of Bufo arenarum embryos to 300-310 nm UV-B at a dose of 4,104 Joule/m2 resulted in 100% lethality within 24 hr while 820 Joule/m2 was the NOEC value for short-term chronic (10 days exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A, 820(B, 1368(C and 1915(D Joule/m2 at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 ± 14.29, 74.5 ± 13.19, 39.5 ± 6.99 and 10.7 ± 1.89 respectively while for control embryos it was 10.88 ± 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure.

  12. Helmintos parásitos de anfibios: Dos Especies de Nemátodos parásitos de Bufo spinulosus trifolium (Tschudi

    Directory of Open Access Journals (Sweden)

    Asucena Naupay

    2014-06-01

    Full Text Available En el presente trabajo sobre los helmintos que parasitan a Bufo spinulosus trifolium (Tschudi de la localidad de Huánuco, se presentan dos especies conocidas para la ciencia pero una de ellas nueva para el Perú.

  13. Use of local visual cues for spatial orientation in terrestrial toads (Rhinella arenarum): The role of distance to a goal.

    Science.gov (United States)

    Daneri, M Florencia; Casanave, Emma B; Muzio, Rubén N

    2015-08-01

    The use of environmental visual cues for navigation is an ability present in many groups of animals. The effect of spatial proximity between a visual cue and a goal on reorientation in an environment has been studied in several vertebrate groups, but never previously in amphibians. In this study, we tested the use of local visual cues (beacons) to orient in an open field in the terrestrial toad (Rhinella arenarum). Experiment 1 showed that toads could orient in space using 2 cues located near the rewarded container. Experiment 2 used only 1 cue placed at different distances to the goal and revealed that learning speed was affected by the proximity to the goal (the closer the cue was to the goal, the faster toads learned its location). Experiment 3 showed that the position of a cue results in a different predictive value. Toads preferred cues located closer to the goal more than those located farther away as a reference for orientation. Present results revealed, for the first time, that (a) toads can learn to orient in an open space using visual cues, and that (b) the effect of spatial proximity between a cue and a goal, a learning phenomenon previously observed in other groups of animals such as mammals, birds, fish, and invertebrates, also affects orientation in amphibians. Thus, our results suggest that toads are able to employ spatial strategies that closely parallel those described in other vertebrate groups, supporting an early evolutionary origin for these spatial orientation skills.

  14. Depth perception in frogs and toads a study in neural computing

    CERN Document Server

    House, Donald

    1989-01-01

    Depth Perception in Frogs and Toads provides a comprehensive exploration of the phenomenon of depth perception in frogs and toads, as seen from a neuro-computational point of view. Perhaps the most important feature of the book is the development and presentation of two neurally realizable depth perception algorithms that utilize both monocular and binocular depth cues in a cooperative fashion. One of these algorithms is specialized for computation of depth maps for navigation, and the other for the selection and localization of a single prey for prey catching. The book is also unique in that it thoroughly reviews the known neuroanatomical, neurophysiological and behavioral data, and then synthesizes, organizes and interprets that information to explain a complex sensory-motor task. The book will be of special interest to that segment of the neural computing community interested in understanding natural neurocomputational structures, particularly to those working in perception and sensory-motor coordination. ...

  15. Phonotaxis to advertisement calls by midwife toads (Alytes muletensis) is not necessarily related to mating

    OpenAIRE

    Lea, Jerry; Dyson, Mandy; Halliday, Timothy

    2002-01-01

    Previous studies with the Mallorcan midwife toad (Alytes muletensis) found that gravid females show inconsistent phonotactic preferences for male calls unless they are highly motivated to mate; and, non-gravid females will occasionally show phonotaxis to male advertisement calls. These results suggest that sometimes phonotaxis may not be related to seeking a mating partner. In this article we report on experiments that give further support to a non-mating function of phonotaxis in this specie...

  16. Storage and recovery of elastic potential energy powers ballistic prey capture in toads.

    Science.gov (United States)

    Lappin, A Kristopher; Monroy, Jenna A; Pilarski, Jason Q; Zepnewski, Eric D; Pierotti, David J; Nishikawa, Kiisa C

    2006-07-01

    Ballistic tongue projection in toads is a remarkably fast and powerful movement. The goals of this study were to: (1) quantify in vivo power output and activity of the depressor mandibulae muscles that are responsible for ballistic mouth opening, which powers tongue projection; (2) quantify the elastic properties of the depressor mandibulae muscles and their series connective tissues using in situ muscle stimulation and force-lever studies; and (3) develop and test an elastic recoil model, based on the observed elastic properties of the depressor mandibulae muscles and series connective tissues, that accounts for displacement, velocity, acceleration and power output during ballistic mouth opening in toads. The results demonstrate that the depressor mandibulae muscles of toads are active for up to 250 ms prior to mouth opening. During this time, strains of up to 21.4% muscle resting length (ML) develop in the muscles and series connective tissues. At maximum isometric force, series connective tissues develop strains up to 14% ML, and the muscle itself develops strains up to 17.5% ML. When the mouth opens rapidly, the peak instantaneous power output of the depressor mandibulae muscles and series connective tissues can reach 9600 W kg(-1). The results suggest that: (1) elastic recoil of muscle itself can contribute significantly to the power of ballistic movements; (2) strain in series elastic elements of the depressor mandibulae muscle is too large to be borne entirely by the cross bridges and the actin-myosin filament lattice; and (3) central nervous control of ballistic tongue projection in toads likely requires the specification of relatively few parameters.

  17. Axial gradients of rhodopsin in light-exposed retinal rods of the toad

    OpenAIRE

    1990-01-01

    Exposure of an intact vertebrate eye to light bleaches the rhodopsin in the photoreceptor outer segments in spatially nonuniform patterns. Some axial bleaching patterns produced in toad rods were determined using microspectrophotometric techniques. More rhodopsin was bleached at the base of the outer segment than at the distal tip. The shape of the bleaching gradient varied with the extent of bleach and with the spectral content of the illuminant. Monochromatic light at the lambda max of the ...

  18. Rapid differentiation of sexual signals in invasive toads: call variation among populations

    OpenAIRE

    Kiyomi Yasumiba; Duffy, Richard L.; Parsons, Scott A.; Ross A Alford; Lin Schwarzkopf

    2016-01-01

    Advertisement calls tend to differ among populations, based on morphological and environmental factors, or simply geographic distance, in many taxa. Invasive cane toads (Rhinella marina) were introduced to Australia in 1935 and their distribution has expanded at increasing rates over time. Rapid evolution occurred in morphological and behavioural characters that accelerate dispersal, but the effects of rapid expansion on sexual signals have not been examined. We collected advertisement calls ...

  19. Deep genetic structure and ecological divergence in a widespread human commensal toad

    OpenAIRE

    Wogan, GOU; Stuart, BL; Iskandar, DT; McGuire, JA

    2016-01-01

    © 2016 The Author(s) Published by the Royal Society. All rights reserved. The Asian common toad (Duttaphrynus melanostictus) is a human commensal species that occupies a wide variety of habitats across tropical Southeast Asia. We test the hypothesis that genetic variation in D. melanostictus is weakly associated with geography owing to natural and human-mediated dispersal facilitated by its commensal nature. Phylogenetic and population genetic analyses of mitochondrial and nuclear DNA sequenc...

  20. About a Snail, a Toad, and Rodents: Animal Models for Adaptation Research

    OpenAIRE

    Roubos, Eric W.; Bruce G. Jenks; Lu eXu; Miyuki eKuribara; Wim J. J. M. Scheenen; Tamas eKozicz

    2010-01-01

    Neural adaptation mechanisms have many similarities throughout the animal kingdom, enabling to study fundamentals of human adaptation in selected animal models with experimental approaches that are impossible to apply in man. This will be illustrated by reviewing research on three of such animal models, viz. (1) the egg-laying behavior of a snail, Lymnaea stagnalis: how one neuron type controls behavior, (2) adaptation to the ambient light condition by a toad, Xenopus laevis: how a neuroendoc...

  1. First report on toxins in the Panamanian toads Atelopus limosus, A. glyphus and A. certus.

    Science.gov (United States)

    Yotsu-Yamashita, Mari; Tateki, Eiko

    2010-01-01

    Major toxins from skin extracts of 18 specimens of six Atelopus toad species collected in Panama were analyzed. Chiriquitoxin was identified using (1)H NMR in A. limosus and A. glyphus for the first time. Zetekitoxin in A. zeteki and tetrodotoxin in A. varius, A. chiriquiensis and A. zeteki were identified again. Furthermore, A. certus was suggested to contain a water-soluble toxin other than tetrodotoxin. PMID:19596024

  2. Antiplasmodial and Cytotoxic Activities of Toad Venoms from Southern Amazon, Brazil.

    Science.gov (United States)

    Banfi, Felipe Finger; Guedes, Karla de Sena; Andrighetti, Carla Regina; Aguiar, Ana Carolina; Debiasi, Bryan Wender; Noronha, Janaina da Costa; Rodrigues, Domingos de Jesus; Júnior, Gerardo Magela Vieira; Sanchez, Bruno Antonio Marinho

    2016-08-01

    The drug-resistance of malaria parasites is the main problem in the disease control. The huge Brazilian biodiversity promotes the search for new compounds, where the animal kingdom is proving to be a promising source of bioactive compounds. The main objective of this study was to evaluate the antiplasmodial and cytotoxic activity of the compounds obtained from the toad venoms of Brazilian Amazon. Toad venoms were collected from the secretion of Rhinella marina and Rhaebo guttatus in Mato Grosso State, Brazil. The powder was extracted at room temperature, yielding 2 extracts (RG and RM) and a substance ('1') identified as a bufadienolide, named telocinobufagin. Growth inhibition, intraerythrocytic development, and parasite morphology were evaluated in culture by microscopic observations of Giemsa-stained thin blood films. Cytotoxicity was determined against HepG2 and BGM cells by MTT and neutral red assays. The 2 extracts and the pure substance ('1') tested were active against chloroquine-resistant Plasmodium falciparum strain, demonstrating lower IC50 values. In cytotoxic tests, the 2 extracts and substance '1' showed pronounced lethal effects on chloroquine-resistant P. faciparum strain and low cytotoxic effect, highlighting toad parotoid gland secretions as a promising source of novel lead antiplasmodial compounds. PMID:27658592

  3. Antiplasmodial and Cytotoxic Activities of Toad Venoms from Southern Amazon, Brazil

    Science.gov (United States)

    Banfi, Felipe Finger; Guedes, Karla de Sena; Andrighetti, Carla Regina; Aguiar, Ana Carolina; Debiasi, Bryan Wender; Noronha, Janaina da Costa; Rodrigues, Domingos de Jesus; Júnior, Gerardo Magela Vieira; Sanchez, Bruno Antonio Marinho

    2016-01-01

    The drug-resistance of malaria parasites is the main problem in the disease control. The huge Brazilian biodiversity promotes the search for new compounds, where the animal kingdom is proving to be a promising source of bioactive compounds. The main objective of this study was to evaluate the antiplasmodial and cytotoxic activity of the compounds obtained from the toad venoms of Brazilian Amazon. Toad venoms were collected from the secretion of Rhinella marina and Rhaebo guttatus in Mato Grosso State, Brazil. The powder was extracted at room temperature, yielding 2 extracts (RG and RM) and a substance (‘1’) identified as a bufadienolide, named telocinobufagin. Growth inhibition, intraerythrocytic development, and parasite morphology were evaluated in culture by microscopic observations of Giemsa-stained thin blood films. Cytotoxicity was determined against HepG2 and BGM cells by MTT and neutral red assays. The 2 extracts and the pure substance (‘1’) tested were active against chloroquine-resistant Plasmodium falciparum strain, demonstrating lower IC50 values. In cytotoxic tests, the 2 extracts and substance ‘1’ showed pronounced lethal effects on chloroquine-resistant P. faciparum strain and low cytotoxic effect, highlighting toad parotoid gland secretions as a promising source of novel lead antiplasmodial compounds. PMID:27658592

  4. Total On-line Access Data System (TOADS): Phase II Final Report for the Period August 2002 - August 2004

    Energy Technology Data Exchange (ETDEWEB)

    Yuracko, K. L. [YAHSGS LLC, Richland, WA (United States); Parang, M. [YAHSGS LLC, Richland, WA (United States); Landguth, D. C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Coleman, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2004-09-13

    TOADS (Total On-line Access Data System) is a new generation of real-time monitoring and information management system developed to support unattended environmental monitoring and long-term stewardship of U.S. Department of Energy facilities and sites. TOADS enables project managers, regulators, and stakeholders to view environmental monitoring information in realtime over the Internet. Deployment of TOADS at government facilities and sites will reduce the cost of monitoring while increasing confidence and trust in cleanup and long term stewardship activities. TOADS: Reliably interfaces with and acquires data from a wide variety of external databases, remote systems, and sensors such as contaminant monitors, area monitors, atmospheric condition monitors, visual surveillance systems, intrusion devices, motion detectors, fire/heat detection devices, and gas/vapor detectors; Provides notification and triggers alarms as appropriate; Performs QA/QC on data inputs and logs the status of instruments/devices; Provides a fully functional data management system capable of storing, analyzing, and reporting on data; Provides an easy-to-use Internet-based user interface that provides visualization of the site, data, and events; and Enables the community to monitor local environmental conditions in real time. During this Phase II STTR project, TOADS has been developed and successfully deployed for unattended facility, environmental, and radiological monitoring at a Department of Energy facility.

  5. Living up to its name? The effect of salinity on development, growth, and phenotype of the "marine" toad (Rhinella marina).

    Science.gov (United States)

    Wijethunga, Uditha; Greenlees, Matthew; Shine, Richard

    2016-02-01

    The highly permeable integument of amphibians renders them vulnerable to chemical characteristics of their environment, especially during the aquatic larval stage. As the cane toad (Rhinella marina, Bufonidae) invades southwards along the east coast of Australia, it is encountering waterbodies with highly variable conditions of temperature, pH, and salinity. Understanding the tolerance of toads to these conditions can clarify the likely further spread of the invader, as well as the adaptability of the species to novel environmental challenges. We measured salinity in waterbodies in the field and conducted laboratory trials to investigate the impacts of salinity on toad viability. Eggs and tadpoles from the southern invasion front tolerated the most saline conditions we found in potential spawning ponds during surveys [equivalent to 1200 ppm (3.5 % the salinity of seawater)]. Indeed, high-salinity treatments increased tadpole body sizes, accelerated metamorphosis, and improved locomotor ability of metamorphs (but did not affect metamorph morphology). At very low salinity [40 ppm (0.1 % seawater)], eggs hatched but larvae did not develop past Gosner stage 37. Our study shows that the egg and larval life stages of cane toads can tolerate wide variation in the salinity of natal ponds and that this aspect of waterbody chemistry is likely to facilitate rather than constrain continued southward expansion of the toad invasion front in eastern Australia. PMID:26553545

  6. Foraging modality and plasticity in foraging traits determine the strength of competitive interactions among carnivorous plants, spiders and toads.

    Science.gov (United States)

    Jennings, David E; Krupa, James J; Rohr, Jason R

    2016-07-01

    Foraging modalities (e.g. passive, sit-and-wait, active) and traits are plastic in some species, but the extent to which this plasticity affects interspecific competition remains unclear. Using a long-term laboratory mesocosm experiment, we quantified competition strength and the plasticity of foraging traits in a guild of generalist predators of arthropods with a range of foraging modalities. Each mesocosm contained eight passively foraging pink sundews, and we employed an experimental design where treatments were the presence or absence of a sit-and-wait foraging spider and actively foraging toad crossed with five levels of prey abundance. We hypothesized that actively foraging toads would outcompete the other species at low prey abundance, but that spiders and sundews would exhibit plasticity in foraging traits to compensate for strong competition when prey were limited. Results generally supported our hypotheses. Toads had a greater effect on sundews at low prey abundances, and toad presence caused spiders to locate webs higher above the ground. Additionally, the closer large spider webs were to the ground, the greater the trichome densities produced by sundews. Also, spider webs were larger with than without toads and as sundew numbers increased, and these effects were more prominent as resources became limited. Finally, spiders negatively affected toad growth only at low prey abundance. These findings highlight the long-term importance of foraging modality and plasticity of foraging traits in determining the strength of competition within and across taxonomic kingdoms. Future research should assess whether plasticity in foraging traits helps to maintain coexistence within this guild and whether foraging modality can be used as a trait to reliably predict the strength of competitive interactions. PMID:27061175

  7. Geology and mammalian paleontology of the Horned Toad Hills, Mojave Desert, California, USA

    Science.gov (United States)

    May, S.R.; Woodburne, M.O.; Lindsay, E.H.; Albright, L.B.; Sarna-Wojcicki, A.; Wan, E.; Wahl, D.B.

    2011-01-01

    The Horned Toad Formation includes five lithostratigraphic members that record alluvial fan, fluvial, lake margin, and lacustrine deposition within a relatively small basin just south of the active Garlock fault during the late Miocene to early Pliocene. These sediments experienced northwest-southeast contractional deformation during the Pliocene-Pleistocene associated with basement-involved reverse faults. Member Two of the Horned Toad Formation has yielded 24 taxa of fossil mammals, referred to as the Warren Local Fauna, including Cryptotis sp., cf. Scapanus, Hypolagus vetus, Hypolagus edensis,? Spermophilus sp., Prothomomys warrenensis n. gen., n. sp., Perognathus sp., Repomys gustelyi, Postcopemys valensis, Peromyscus sp. A, Peromyscus sp. B, Jacobsomys dailyi n. sp., Borophagus cf. B. secundus, cf. Agriotherium, Machairodus sp. cf. M. coloradensis, Rhynchotherium sp. cf. R. edensis, Pliomastodon vexillarius, Dinohippus edensis, Teleoceras sp. cf. T. fossiger, cf. Prosthennops, Megatylopus sp. cf. M. matthewi, Hemiauchenia vera, Camelidae gen. et. sp. indet., and the antilocaprid cf. Sphenophalos. The majority of fossil localities are confined to a 20 m thick stratigraphic interval within a reversed polarity magnetozone. The fauna demonstrates affinity with other late Hemphillian faunas from California, Nevada, Nebraska, Texas, and Mexico. The Lawlor Tuff, dated elsewhere in California at 4.83 ?? 0.04 Ma and geochemically identified in the Horned Toad Formation, overlies most of the fossil mammal localities. Magnetic polarity data are correlated with Chrons 3n.3r, 3n.3n, and 3n.2r, suggesting an age of approximately 5.0 - 4.6 Ma. These constraints indicate an age for the late Hemphillian Warren Local Fauna of 4.85 - 5.0 Ma. ?? Society of Vertebrate Paleontology November 2011.

  8. The role of common toads in the winter diet of recolonising Eurasian otters (Lutra lutra

    Directory of Open Access Journals (Sweden)

    Pablo García-Díaz

    2011-02-01

    Full Text Available Importanza del rospo comune nella dieta invernale di una popolazione di lontra (Lutra lutra in espansione.
    Tramite analisi dei resti fecali, abbiamo evidenziato il ruolo fondamentale degli anfibi nella dieta invernale della lontra Lutra lutra in stagni artificiali della Spagna nord-occidentale. I numerosi “laghi di cava” presenti nell’area umida di Ribeiras do Louro e Gandaras de Budiño sono stati monitorati nel 2007-2009. Il rospo comune (Bufo bufo era la principale preda della lontra, costituendo l’88% della biomassa consumata, mentre il gambero americano Procambarus clarkii e i pesci erano prede secondarie. I nostri risultati contrastano con la ben nota preferenza della lontra per le rane rispetto al rospo. Il mantenimento della popolazione di lontra nel bacino del fiume Louro dipende strettamente dalla corretta gestione degli stagni artificiali.

  9. Aversive and non-reward learning in the fire-bellied toad using familiar and unfamiliar prey stimuli

    Institute of Scientific and Technical Information of China (English)

    Ursula DICKE; Antje HEIDORN; Gerhard ROTH

    2011-01-01

    The present study investigated how snapping behavior toward familiar and unfamiliar prey is modified by reward omission and aversive conditioning in the fure-bellied toad Bombina orientalis.Toads were trained to snap at cricket images by rewarding them with live crickets.The task was learned,and the learning criterion (10 snapping responses within 2 minutes) was reached in all individuals investigated.Subsequent reward omission did not alter the frequency of snapping to the familiar cricket stimulus.Snapping decreased only in some individuals,when a mild foot shock was applied at snapping.However,at presentation of images of hitherto unfamiliar meal worms and foot-shock application at snapping to the stimulus,the majority of toads diminished snapping significantly.Snapping responses decreased more rapidly,when snapping at meal worms was not rewarded or a footshock was applied uncorrelated to the presentation of or snapping at meal worms.These results demonstrate that in toads familiarity and unfamiliarity of prey stimuli are important factors in aversive learning,because well-trained responses to familiar stimuli become immune against reward omission.Furthermore,at presentation of unfamiliar stimuli,omission of reward and uncorrelated footshock had a stronger aversive effect than correlated footshock [Current Zoology 57 (6):709-716,2011 ].

  10. 77 FR 6815 - Emergency Exemption; Issuance of Emergency Permit To Salvage Houston Toads Affected by a Wildfire...

    Science.gov (United States)

    2012-02-09

    ... for public inspection, by appointment only, during normal business hours at the U.S. Fish and Wildlife... the FEMA clean-up. Efforts to salvage adults, juveniles, tadpoles, or egg masses are currently taking... toads may include the following activities: collect as adults, juveniles, tadpoles, or eggs from...

  11. Alfaxalone-butorphanol versus alfaxalone-morphine combination for immersion anaesthesia in oriental fire-bellied toads (Bombina orientalis).

    Science.gov (United States)

    Adami, Chiara; d'Ovidio, Dario; Casoni, Daniela

    2016-06-01

    Oriental fire-bellied toads (Bombina orientalis) are small semi-aquatic anuran species popular as both pets and laboratory animals. Although they are commonly anaesthetized to undergo clinical and experimental procedures, very little is known about their anaesthetic management. The aims of this prospective, randomized, cross-over experimental trial were to establish effective butorphanol and morphine concentrations to be added to alfaxalone for immersion anaesthesia (pilot study), and to compare the anaesthetic and antinociceptive effects of the two drug mixtures (alfaxalone-butorphanol and alfaxalone-morphine), in Bombina orientalis toads. For the actual trial, the toads were randomly assigned to one of two treatment groups: AB and AM, with seven animals in each group, which received alfaxalone-butorphanol and alfaxalone-morphine combinations, respectively, at the concentrations established during the pilot study. Heart rate, respiratory rate, von Frey filament threshold and response to nociceptive withdrawal (NWR), righting and myotactic reflexes were measured at 5 min intervals until return of righting reflex was observed. The investigator who carried out all the measurements was blinded to the treatment. Any undesired effect or complication was noted and recorded. The two treatments were found to be comparable in terms of onset and duration of anaesthesia, and occurrence of undesired effects. However, group AM resulted in lower NWR scores and higher von Frey filament thresholds than group AB. It is concluded that, at the investigated concentrations and in combination with alfaxalone by immersion, morphine provides better antinociception than butorphanol in oriental fire-bellied toads.

  12. Modification of a prey catching response and the development of behavioral persistence in the fire-bellied toad (Bombina orientalis).

    Science.gov (United States)

    Ramsay, Zachary J; Ikura, Juntaro; Laberge, Frédéric

    2013-11-01

    The present report investigated how fire-bellied toads (Bombina orientalis) modified their response in a prey catching task in which the attribution of food reward was contingent on snapping toward a visual stimulus of moving prey displayed on a computer screen. Two experiments investigated modification of the snapping response, with different intervals between the opportunity to snap at the visual stimulus and reward administration. The snapping response of unpaired controls was decreased compared with the conditioned toads when hour or day intervals were used, but intervals of 5 min produced only minimal change in snapping. The determinants of extinction of the response toward the visual stimulus were then investigated in 3 experiments. The results of the first experiment suggested that increased resistance to extinction depended mostly on the number of training trials, not on partial reinforcement or the magnitude of reinforcement during training. This was confirmed in a second experiment showing that overtraining resulted in resistance to extinction, and that the pairing of the reward with a response toward the stimulus was necessary for that effect, as opposed to pairing reward solely with the experimental context. The last experiment showed that the time elapsed between training trials also influenced extinction, but only in toads that received few training trials. Overall, the results suggest that toads learning about a prey stimulus progress from an early flexible phase, when an action can be modified by its consequences, to an acquired habit characterized by an increasingly inflexible and automatic response.

  13. Behavioral and neural responses of toads to salt solutions correlate with basolateral membrane potential of epidermal cells of the skin

    DEFF Research Database (Denmark)

    Hillyard, Stanley D; Baula, Victor; Tuttle, Wendy;

    2007-01-01

    Dehydrated toads initiated water absorption response (WR) behavior and absorbed water from dilute NaCl solutions. With 200-250 mM NaCl, WR behavior and water absorption were both suppressed. With 200-250 mM Na-gluconate, WR initiation was significantly greater than with NaCl but water loss was gr...

  14. Larger body size at metamorphosis enhances survival, growth and performance of young cane toads (Rhinella marina.

    Directory of Open Access Journals (Sweden)

    Elisa Cabrera-Guzmán

    Full Text Available Body size at metamorphosis is a key trait in species (such as many anurans with biphasic life-histories. Experimental studies have shown that metamorph size is highly plastic, depending upon larval density and environmental conditions (e.g. temperature, food supply, water quality, chemical cues from conspecifics, predators and competitors. To test the hypothesis that this developmental plasticity is adaptive, or to determine if inducing plasticity can be used to control an invasive species, we need to know whether or not a metamorphosing anuran's body size influences its subsequent viability. For logistical reasons, there are few data on this topic under field conditions. We studied cane toads (Rhinella marina within their invasive Australian range. Metamorph body size is highly plastic in this species, and our laboratory studies showed that larger metamorphs had better locomotor performance (both on land and in the water, and were more adept at catching and consuming prey. In mark-recapture trials in outdoor enclosures, larger body size enhanced metamorph survival and growth rate under some seasonal conditions. Larger metamorphs maintained their size advantage over smaller siblings for at least a month. Our data support the critical but rarely-tested assumption that all else being equal, larger body size at metamorphosis is likely to enhance an individual's long term viability. Thus, manipulations to reduce body size at metamorphosis in cane toads may help to reduce the ecological impact of this invasive species.

  15. Diffusion of 133Xe through frog skins, toad bladders, and water boundary layers

    International Nuclear Information System (INIS)

    We have measured the total permeability coefficients P as a function of stirring frequency ω for 133Xe through frog skins and toad bladders. The permeability coefficients for the frog skins and toad bladders proper are, respectively, P/sub m/ = (3.9 +- 0.8) x 10-4 cm/s and (7.4 +- 4.2) x 10-4 cm/s. ''Unstirred'' water layer thickness delta is determined concurrently, from the frequency dependence of P(ω); the result for frog skin is delta = (0.060 +- 0.016)/√ω(rad/s) cm. The stirring frequency range is from ω = 7.5 rad/s (72 rpm) to 55 rad/s (530 rpm). The results support the conclusions that the principal barrier to Xe diffusion in these epithelia is inter- and intracellular water, and that the diffusion is passive and rapid. The experimental method may be straightforwardly adapted to the measurement of diffusion or counterdiffusion of any gamma-radioactive soluble or partly soluble solute through any flat membrane or through a solvent. We estimate the amount of total body-absorbed radioactivity due to environmental 133Xe to be 50 fCi for an ambient concentration of 2.6 pCi/m3 of air

  16. spatial distribution pattern of the steppe toad-headed lizard (phrynocephalus frontalis) and its influencing factors

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    spatial distribution patterns are associated with life history and behavioral adaptations of animals.for studying the spatial distribution pattern of the steppe toad-headed lizard (phrynocephalusfrontalis) and its influencing factors,we conducted experiments in hunshandake sandy land in inner mongolia,china in july 2009.by calculating the clustered indices,we found that the lizard was aggregately distributed when the sampling quadrat was smaller than 10 m × 10 m,and uniformly distributed when it was greater than 10 m × 10 m.the nearest neighbor rule showed a clustering distribution pattern for p frontalis and the distribution pattern was quadrat-sampling dependent.furthermore,the cluster was determined by environmental factors when the sampling quadrat was smaller than 20 m × 20 m,but it was determined by both environmental factors and characteristics of the lizard when it was larger than 20 m × 20 m.our results suggested that the steppe toad-headed lizards tended to aggregate into suitable habitat patches in desert areas.additionally,we discussed that the lizard aggregation could be potentially used as an indictor of movement of sand dunes.

  17. ELECTRON MICROSCOPY OF ABSORPTION OF TRACER MATERIALS BY TOAD URINARY BLADDER EPITHELIUM.

    Science.gov (United States)

    CHOI, J K

    1965-05-01

    The absorption of Thorotrast and saccharated iron oxide by the epithelium of the toad urinary bladder was studied by electron microscopy. Whether the toads were hydrated, dehydrated, or given Pitressin, no significant differences in transport of colloidal particles by epithelial cells were observed. This implies that these physiological factors had little effect on the transport of the tracer particles. Tracer particles were encountered in three types of epithelial cells which line the bladder lumen, but most frequently in the mitochondria-rich cells. Tracer materials were incorporated into the cytoplasm of epithelial cells after being adsorbed to the coating layer covering the luminal surface of the cells. In the intermediate stage (1 to 3 hours after introducing tracer) particles were present in small vesicles, tubules, and multivesicular bodies. In the later stages (up to 65 hours), the particles were more commonly seen to be densely packed within large membrane-bounded bodies which were often found near the Golgi region. These large bodies probably were formed by the fusion of small vesicles. Irrespective of the stages of absorption, no particles were found in the intercellular spaces or in the submucosa. Particles apparently did not penetrate the intercellular spaces of the epithelium beyond the level of the tight junction.

  18. Functional assessment of toad parotoid macroglands: a study based on poison replacement after mechanical compression.

    Science.gov (United States)

    Jared, Simone G S; Jared, Carlos; Egami, Mizue I; Mailho-Fontana, Pedro L; Rodrigues, Miguel T; Antoniazzi, Marta M

    2014-09-01

    Toads have a pair of parotoid macroglands behind the eyes that secrete poison used in passive defence against predators. These macroglands are composed of juxtaposed alveoli, each one bearing a syncytial gland, all connected to the exterior by ducts. When the parotoids are bitten, the poison is expelled on the predator oral mucosa in the form of jets, causing several pharmacological actions. After poison release, the empty secretory syncytia immediately collapse in the interior of their respective alveoli and gradually start refilling. After parotoid manual compression, simulating a predator's bite, we studied, by means of morphological methods, the replacement of the poison inside the alveoli. The results showed that after compression, a considerable number of alveoli remained intact. In the alveoli that were effectively affected the recovery occurs in different levels, from total to punctual and often restrict to some areas of the syncytia. The severely affected alveoli seem not recover their original functional state. The fact that only a part of the parotoid alveoli is compressed during an attack seems to be crucial for toad survival, since the amphibian, after being bitten by a predator, do not lose all its poison stock, remaining protected in case of new attacks. PMID:24911375

  19. CRED Optical Validation Data at the island of Ofu and Olosega in American Samoa, 2012 to support Benthic Habitat Mapping (TOAD)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Optical validation data were collected using the Tethered Optical Assessment Device (TOAD), a sled equipped with underwater video camera, still camera and lights....

  20. Morphological and genetic differentiation among Chilean populations of Bufo spinulosus (Anura: Bufonidae Diferenciación morfológica y genética entre poblaciones chilenas de Bufo spinulosus (Anura: Bufonidae

    Directory of Open Access Journals (Sweden)

    Marco A. Méndez

    2004-09-01

    Full Text Available Bufo spinulosus has a wide and fragmented range distribution in Chile (18° to 33° S along altitudinal and latitudinal gradients. Genetic variation was estimated using RAPD (Random Amplified Polymorphic DNA markers in 10 populations from northern and central Chile. Morphometric and genetic information was analyzed as a function of geographical origin. The correlation between genetic and morphometric differentiation was analyzed by the Mantel test. An increase in body size as a function of latitude was observed. Specimens from El Tatio had the smallest body size and the greatest morphometric divergence. The AMOVA applied to genetic data indicated that 57.85 % of the variance is explained by interregional differences and that 30.12 % of the variance is found within populations. Low levels of within-regions genetic differentiation was observed in northern populations while higher levels of genetic differentiation was found in populations from central Chile. Mantel tests revealed a significant, positive correlation between genetic variation and geographic distance. When we excluded El Tatio population, Mantel test analyses showed significant correlations between morphological distance and genetic and geographic distances. We discuss whether water temperature could explain the morphological divergence observed in individuals from El TatioBufo spinulosus presenta una amplia y fragmentada distribución en Chile (18º a 33º S a lo largo de gradientes altitudinales y latitudinales. La variación genética fue estimada utilizando marcadores RAPD ("Random Amplified Polymorphic DNA" en diez poblaciones del norte y centro de Chile. La información morfométrica y genética fue analizada en función de la procedencia geográfica. La correlación entre diferenciación genética y morfométrica fue analizada utilizando la prueba de Mantel. Se observó un incremento en el tamaño corporal en función de la latitud. Los individuos de El Tatio mostraron el tama

  1. New regional record and notes on historical specimens of Gunther Toad Duttaphrynus hololius with comments on other southeastern Indian congeners

    OpenAIRE

    Srinivasulu, B.; S.R. Ganesh; C. Srinivasulu

    2013-01-01

    We report on the finding of the Günther Toad Duttaphrynus hololius from Visakhapatnam and discuss aspects of its distribution based on our species distribution modeling. We also provide data on historically collected specimens and refine its intra-specific variation, provide an up-to-date chresonymy and comment on the validity of earlier reported diagnosis. Lastly, we remark on some misidentification-mediated dubious southern Indian records of another, related congener, the Marbled Toad D. ...

  2. Peptide IC-20, encoded by skin kininogen-1 of the European yellow-bellied toad, Bombina variegata, antagonizes bradykinin-induced arterial smooth muscle relaxation

    OpenAIRE

    Mu Yang; Mei Zhou; Bing Bai; Chengbang Ma; Le Wei; Lei Wang; Tianbao Chen; Chris Shaw

    2011-01-01

    Objectives: The objectives were to determine if the skin secretion of the European yellow-bellied toad (Bombina variegata), in common with other related species, contains a bradykinin inhibitor peptide and to isolate and structurally characterize this peptide. Materials and Methods: Lyophilized skin secretion obtained from this toad was subjected to reverse phase HPLC fractionation with subsequent bioassay of fractions for antagonism of the bradykinin activity using an isolated rat tail arter...

  3. EFFECT OF ANGELICA SINENSIS ON AFFERENT DISCHARGE OF SINGLE MUSCLE SPINDLE IN TOADS

    Institute of Scientific and Technical Information of China (English)

    高云芳; 樊小力

    2004-01-01

    Objective In drugs for invigorating blood circulation, to find a herb that can stimulate afferent discharge of muscle spindle. Methods A single muscle spindle was isolated from sartorial muscle of toad. Using air-gap technique, afferent discharge of the muscle spindle was recorded. Effects of Angelica Sinensis, Salvia Miltiorrhiza, and Safflower on afferent discharge of the muscle spindle were observed. Results Angelica Sinensis could distinctly increase afferent discharge frequency of the muscle spindle, and this increase was dose-dependent. But Salvia Miltiorrhiza and Safflower had no this excitatory effect. Conclusion It is known that Angelica Sinensis can invigorate blood circulation, and we have found its excitatory effect on muscle spindle which makes it possible to serve people with muscle atrophy if more evidences from clinical experiments are available.

  4. Cytological evidence for population-specific sex chromosome heteromorphism in Palaearctic green toads (Amphibia, Anura)

    Indian Academy of Sciences (India)

    G Odierna; G Aprea; T Capriglione; S Castellano; E Balletto

    2007-06-01

    A chromosome study was carried out on a number of European and Central Asiatic diploid green toad populations by means of standard and various other chromosome banding and staining methods (Ag-NOR-, Q-, CMA3-, late replicating [LR] banding pattern, C- and sequential C-banding + CMA3 + DAPI). This study revealed the remarkable karyological uniformity of specimens from all populations, with the only exception being specimens from a Moldavian population, where one chromosome pair was heteromorphic. Though similar in shape, size and with an identical heterochromatin distribution, the difference in the heteromorphic pair was due to a large inverted segment on its long arms. This heteromorphism was restricted to females, suggesting a female heterogametic sex chromosome system of ZZ/ZW type at a very early step of differentiation.

  5. KARYOTYPIC STUDY OF THE COMMON INDIAN TOAD, DUTTAPHRYNUS MELANOSTICTUS, FROM JAMMU AND KASHMIR, INDIA

    Directory of Open Access Journals (Sweden)

    Neelam Saba

    2014-01-01

    Full Text Available Karyotypic study of two sexes of the toad species, Duttaphrynus melanostictus, was carried out using giemsa staining, C- banding and NOR banding methods, from Jammu and Kashmir, India. The basic chromosome number was found to be 2n=22, fundamental arm number (NF was 44 with all the biarmed chromosomes and no sex chromosome heteromorphism was found. Cbanding and NOR banding was also performed. Paracentric C-band was on the long arm of first homologous pair. Centromeric heterochromatin appeared as darkly stained C-bands on all the chromosomes of diploid complement, whereas Ag-NOR staining showed a pair of nucleolar organizer regions present on pair no. 7 on short arm i.e. 7p in both male and female karyotypes.

  6. Rapid differentiation of sexual signals in invasive toads: call variation among populations.

    Science.gov (United States)

    Yasumiba, Kiyomi; Duffy, Richard L; Parsons, Scott A; Alford, Ross A; Schwarzkopf, Lin

    2016-01-01

    Advertisement calls tend to differ among populations, based on morphological and environmental factors, or simply geographic distance, in many taxa. Invasive cane toads (Rhinella marina) were introduced to Australia in 1935 and their distribution has expanded at increasing rates over time. Rapid evolution occurred in morphological and behavioural characters that accelerate dispersal, but the effects of rapid expansion on sexual signals have not been examined. We collected advertisement calls from four populations of different ages since invasion, and analysed the geographic differentiation of seven call parameters. Our comparisons indicate that the calls of R. marina differ among Australian populations. The signal variation was not simply clinal with respect to population age, climate, or morphological differentiation. We suggest that selection on signalling among populations has been idiosyncratic and may reflect local female preferences or adaptation to environmental factors that are not clinal such as energy availability. PMID:27328666

  7. Telencephalic neural activation following passive avoidance learning in a terrestrial toad.

    Science.gov (United States)

    Puddington, Martín M; Daneri, M Florencia; Papini, Mauricio R; Muzio, Rubén N

    2016-12-15

    The present study explores passive avoidance learning and its neural basis in toads (Rhinella arenarum). In Experiment 1, two groups of toads learned to move from a lighted compartment into a dark compartment. After responding, animals in the experimental condition were exposed to an 800-mM strongly hypertonic NaCl solution that leads to weight loss. Control animals received exposure to a 300-mM slightly hypertonic NaCl solution that leads to neither weight gain nor loss. After 10 daily acquisition trials, animals in the experimental group showed significantly longer latency to enter the dark compartment. Additionally, 10 daily trials in which both groups received the 300-mM NaCl solution after responding eliminated this group effect. Thus, experimental animals showed gradual acquisition and extinction of a passive avoidance respond. Experiment 2 replicated the gradual acquisition effect, but, after the last trial, animals were sacrificed and neural activation was assessed in five brain regions using AgNOR staining for nucleoli-an index of brain activity. Higher activation in the experimental animals, relative to controls, was observed in the amygdala and striatum. Group differences in two other regions, lateral pallium and septum, were borderline, but nonsignificant, whereas group differences in the medial pallium were nonsignificant. These preliminary results suggest that a striatal-amygdala activation could be a key component of the brain circuit controlling passive avoidance learning in amphibians. The results are discussed in relation to the results of analogous experiments with other vertebrates. PMID:27498147

  8. Nux Vomica 200 CH reduced acute hypnotic effect of alcohol in young toads

    Directory of Open Access Journals (Sweden)

    Nirmal Sukul

    2012-09-01

    Full Text Available Potentized Nux Vomica has been reported to produce antialcoholic effect in mice, rats and toads. The effect relates to consumption of alcohol and alcohol-induced loss of righting reflex (RR. RR’s maintain normal erect posture of an animal and are centrally controlled in the midbrain. In the present study young toads, Duttaphrynus melanostictus were first treated with Nux vomica 200 CH and then partially immersed in 209 mM ethanol solution in such a way that their head remained above the level of ethanol solution. Toadlets were removed from the ethanol solution every 10 min, tested for the loss of RR and returned to the ethanol solution. Toadlets were placed in a supine position on a dry flat surface. Failure to right within 60 sec was considered as the loss of RR. The experiment was repeated 10 times. Control toadlets were pretreated with 90% ethanol instead of Nux Vomica 200 CH. The percentages of toadlets showing loss of RR, both in the control as well as in the Nux-treated groups, were shown in graphs against the duration of exposure to ethanol solution. Differences in the percentage distribution between the control and the treatment groups losing RR were tested by χ2 test. All the experiments were conducted at room temperature. The percentage of toadlets losing RR increased with time of exposure to ethanol solution. The increase was significantly higher with the control than with the Nux-treated group. Nux Vomica 200 CH might have influenced the mid-brain of toadlets thereby countering the hypnotic effect of ethanol in the toadlets.

  9. Isolation of radio-iodinated apical and basal-lateral plasma membranes of toad bladder epithelium.

    Science.gov (United States)

    Rodriguez, H J; Edelman, I S

    1979-04-01

    The apical and basal-lateral plasma membranes of toad bladder epithelium were radio-iodinated with the glucose-glucose oxidase-lactoperoxidase system. The covalently bound radio iodine was used as a marker during subcellular fractionation and membrane isolation. Homogenization conditions that ensured rupture of more than 80% of the cells without substantial nuclear damage were defined by Normarski optics. The nuclei were separated by differential centrifugation and the apical and basal-lateral components were resolved by differential and sucrose density gradient centrifugation. The apical components yielded two radioactive bands that were identified as glycocalyx and plasma membrane labeled with 125I. The basal-lateral components yielded a hetero-disperse pattern made up of at least 3 radioactive bands, but the bulk of the activity of ouabain-sensitive ATPase comigrated with only one of these bands. The mitochondia, identified by assays for cytochrome oxidase and NADH cytochrome c reductase activities, were separated from the radio-iodine labeled by centrifugation in sucrose density gradients under isokinetic conditions. The labeled glycocalyx and the slowly migrating components of basal-lateral labeling were separated from the radio-iodinated membranes by centrifugation at 100,000 x g x 1 hr after removal of the mitochrondria by the isokinetic method. The labeled membranes were then subjected to ultracentrifugation in sucrose density gradients under isopycnic conditions; the basal-lateral membranes containing ouabain-sensitive ATP-ase were well resolved from the apical membranes by this method. These results provide a relatively rapid method of attaining partial purification of the apical and basal-lateral plasma membranes of toad bladder epithelium. PMID:222911

  10. Density regulation in toad populations (Epidalea calamita, Bufotes viridis) by differential winter survival of juveniles.

    Science.gov (United States)

    Sinsch, Ulrich; Schäfer, Alena M

    2016-01-01

    The size of amphibian populations varies considerably between years, so that systematic trends in dynamics are difficult to detect. Informed conservation management of presumably declining populations requires the identification of the most sensitive life stage. In temperate-zone anurans there is growing evidence that juveniles hibernating for the first time suffer from substantial winter losses. In two syntopic toads (Epidalea calamita, Bufotes viridis) we monitored survival of such juveniles during four consecutive winters in the natural habitat and in four temperature treatments (3°, 5 °C, 10°/15 °C or 20 °C, natural light-dark cycle) in temperature-controlled chambers during winter. Specifically, we tested the hypotheses that (1) winter mortality of juvenile toads which hibernate for the first time in their life is an important component of population dynamics, and that (2) mortality rates differed between the two species. Parameters quantified were size-dependent winter mortality and body condition of pre- and post-hibernating juveniles. Field data provided evidence for the important role of winter mortality of first-hibernators in population dynamics. Choice of hibernacula differed in E. calamita between small and medium-sized individuals and also between the two species suggesting distinct mortality risks. The inability of small E. calamita to reach frost-proof hibernacula by burrowing, and the exposure of small B. viridis to predators are the most probable causes of size-assortative winter mortality. In conclusion, E. calamita juveniles may benefit from rising average winter temperatures in the future by decreased risk of freezing to death, whereas predator-caused winter mortality of B. viridis juveniles will also depend on the effects of climate warming on predator phenology.

  11. Frogs in the spotlight: a 16-year survey of native frogs and invasive toads on a floodplain in tropical Australia.

    Science.gov (United States)

    Brown, Gregory P; Shine, Richard

    2016-07-01

    Although widespread declines in anuran populations have attracted considerable concern, the stochastic demographics of these animals make it difficult to detect consistent trends against a background of spatial and temporal variation. To identify long-term trends, we need datasets gathered over long time periods, especially from tropical areas where anuran biodiversity is highest. We conducted road surveys of four anurans in the Australian wet-dry tropics on 4637 nights over a 16-year period. Our surveys spanned the arrival of invasive cane toads (Rhinella marina), allowing us to assess the invader's impact on native anuran populations. Our counts demonstrate abrupt and asynchronous shifts in abundance and species composition from one year to the next, not clearly linked to rainfall patterns. Typically, periods of decline in numbers of a species were limited to 1-2 years and were followed by 1- to 2-year periods of increase. No taxa showed consistent declines over time, although trajectories for some species showed significant perturbations coincident with the arrival of toads. None of the four focal frog species was less common at the end of the study than at the beginning, and three of the species reached peak abundances after toad arrival. Survey counts of cane toads increased rapidly during the initial stage of invasion but have subsequently declined and fluctuated. Distinguishing consistent declines versus stochastic fluctuations in anuran populations requires extensive time-series analysis, coupled with an understanding of the shifts expected under local climatic conditions. This is especially pertinent when assessing impacts of specific perturbations such as invasive species. PMID:27386087

  12. Checklist and Simple Identification Key for Frogs and Toads from District IV of The MADA Scheme, Kedah, Malaysia

    OpenAIRE

    Jaafar, Ibrahim; Chai, Teoh Chia; Sah, Shahrul Anuar Mohd; Akil, Mohd Abdul Muin Md.

    2009-01-01

    A survey was conducted to catalogue the diversity of anurans in District IV of the Muda Agriculture Development Authority Scheme (MADA) in Kedah Darul Aman, Malaysia, from July 1996 to January 1997. Eight species of anurans from three families were present in the study area. Of these, the Common Grass Frog (Fejevarya limnocharis) was the most abundant, followed by Mangrove Frog (Fejevarya cancrivora), Long-legged Frog (Hylarana macrodactyla), and Common Toad (Duttaphrynus melanostictus). Pudd...

  13. Lethal and sub-lethal effects on the Asian common toad Duttaphrynus melanostictus from exposure to hexavalent chromium.

    Science.gov (United States)

    Fernando, Vindhya A K; Weerasena, Jagathpriya; Lakraj, G Pemantha; Perera, Inoka C; Dangalle, Chandima D; Handunnetti, Shiroma; Premawansa, Sunil; Wijesinghe, Mayuri R

    2016-08-01

    Chromium discharged in industrial effluents frequently occurs as an environmental pollutant, but the lethal and sub-lethal effects the heavy metal might cause in animals exposed to it have been insufficiently investigated. Selecting the amphibian Duttaphrynus melanostictus, we carried out laboratory tests to investigate the effects of short and long term exposure to hexavalent chromium (Cr(VI)) in both tadpoles and adult toads. The concentrations used were 0.002, 0.02, 0.2, 1.0 and 2.0mg/L, the first three corresponding to field levels. In vitro exposures were also carried out using toad erythrocytes and Cr(VI) concentrations of 0.0015, 0.003, 0.015, 0.03, 0.15mg/L. Mortality, growth retardation, developmental delays and structural aberrations were noted in the metal-treated tadpoles, with increasing incidence corresponding to increase in Cr(VI) level and duration of exposure. Many of the sub-lethal effects were evident with long term exposure to environmentally relevant levels of the toxicant. Changes in selected blood parameters and erythrocyte morphometry were also detected in Cr(VI) exposed toads, indicating anaemic and leucopenic conditions. In the genotoxicity study, DNA damage indicated by comet assay and increased micronuclei frequency, occurred at the low Cr(VI) concentrations tested. The multiple deleterious effects of exposure to chromium signal the need for monitoring and controlling the discharge of chromium to the environment. The dose-dependency and genotoxic effects observed in this widely distributed Asian toad indicates its suitability for monitoring heavy metal pollution in aquatic systems. PMID:27262939

  14. Survey of helminths, ectoparasites, and chytrid fungus of an introduced population of cane toads, Rhinella marina (Anura: Bufonidae), from Grenada

    Science.gov (United States)

    Drake, Michael C.; Zieger, Ulrike; Groszkowski, Andrew; Gallardo, Bruce; Sages, Patti; Reavis, Roslyn; Faircloth, Leslie; Jacobson, Krystin; Lonce, Nicholas; Pinckney, Rhonda D.; Cole, Rebecca Ann

    2014-01-01

    One hundred specimens of Rhinella marina, (Anura: Bufonidae) collected in St. George's parish, Grenada, from September 2010 to August 2011, were examined for the presence of ectoparasites and helminths. Ninety-five (95%) toads were parasitized by one or more parasite species. Nine species of parasites were found: 1 digenean, 2 acanthocephalans, 4 nematodes, 1 arthropod and 1 pentastome. The endoparasites represented 98.9% of the total number of parasite specimens collected. Grenada represents a new locality record for Mesocoelium monas, Raillietiella frenatus, Pseudoacanthacephalus sp., Aplectana sp., Physocephalus sp., Acanthacephala cystacanth and Physalopteridae larvae. The digenean M. monas occurred with the highest prevalence of 82%, contrasting many studies of R. marina where nematodes dominate the parasite infracommunity. Female toads were found to have a significantly higher prevalence of Amblyomma dissimile than male toads. Only two parasites exhibited a significant difference between wet and dry season with Parapharyngodon grenadensis prevalence highest in the wet season and A. dissimile prevalence highest during the dry season. Additionally, A. dissimile was significantly more abundant during the dry season.

  15. Effects of acute low temperature stress on the endocrine reactions of the Qinghai toad-headed lizard

    Institute of Scientific and Technical Information of China (English)

    Chunwang LI; Yuan GU; Songhua TANG; Hongxia FANG; Guohua JIANG; Zhigang JIANG

    2011-01-01

    Endocrinological action is generally thought to be a way for animals to respond to stress at low temperatures.To learn the role of hormones in eetotherms inhabiting alpine environments,we studied the effects of acute low temperature exposure on the endocrinological reactions of Qinghai toad-headed lizards in the Qinghai-Tibetan Plateau.We monitored plasma corticosterone and insulin concentration of the lizards under five low temperature treatments.We found no significant difference in plasma corticosterone or insulin in lizards among our five different treatments.For males and females the correlation between plasma corticosterone and insulin concentrations was not significant.In contrast to other studies on reptiles at low altitude,we suggest that due to the alpine environment (low temperature and low oxygen concentration) they inhabit,Qinghai toad-headed lizards respond to experimental cold stress slightly to mobilize energy and live their vivid life.In addition,corticosterone and insulin of Qinghai toad-headed lizards are secreted independently along with low temperature treatments [Current Zoology 57 (6):775-780,2011].

  16. Evolution of rapid development in spadefoot toads is unrelated to arid environments.

    Science.gov (United States)

    Zeng, Cen; Gomez-Mestre, Ivan; Wiens, John J

    2014-01-01

    The extent to which species' life histories evolve to match climatic conditions is a critical question in evolutionary biology and ecology and as human activities rapidly modify global climate. GIS-based climatic data offer new opportunities to rigorously test this question. Superficially, the spadefoot toads of North America (Scaphiopodidae) seem to offer a classic example of adaptive life-history evolution: some species occur in extremely dry deserts and have evolved the shortest aquatic larval periods known among anurans. However, the relationships between the climatic conditions where spadefoots occur and the relevant life-history traits have not been explicitly tested. Here, we analyzed these relationships using GIS-based climatic data, published life-history data, and a time-calibrated phylogeny for pelobatoid frogs. Surprisingly, we find no significant relationships between life-history variables and precipitation or aridity levels where these species occur. Instead, rapid development in pelobatoids is strongly related to their small genome sizes and to phylogeny. PMID:24800832

  17. Analysis of heart rate control to assess thermal sensitivity responses in Brazilian toads.

    Science.gov (United States)

    Natali, J E S; Santos, B T; Rodrigues, V H; Chauí-Berlinck, J G

    2015-01-01

    In anurans, changes in ambient temperature influence body temperature and, therefore, energy consumption. These changes ultimately affect energy supply and, consequently, heart rate (HR). Typically, anurans living in different thermal environments have different thermal sensitivities, and these cannot be distinguished by changes in HR. We hypothesized that Rhinella jimi (a toad from a xeric environment that lives in a wide range of temperatures) would have a lower thermal sensitivity regarding cardiac control than R. icterica (originally from a tropical forest environment with a more restricted range of ambient temperatures). Thermal sensitivity was assessed by comparing animals housed at 15° and 25°C. Cardiac control was estimated by heart rate variability (HRV) and heart rate complexity (HRC). Differences in HRV between the two temperatures were not significant (P=0.214 for R. icterica and P=0.328 for R. jimi), whereas HRC differences were. All specimens but one R. jimi had a lower HRC at 15°C (all Pthermal sensitivity and that cardiac control is not completely dependent on the thermal environment because HRC was not consistently different between temperatures in all R. jimi specimens. This result indicates a lack of evolutive trade-offs among temperatures given that heart rate control at 25°C is potentially not a constraint to heart rate control at 15°C.

  18. Deep genetic structure and ecological divergence in a widespread human commensal toad.

    Science.gov (United States)

    Wogan, Guinevere O U; Stuart, Bryan L; Iskandar, Djoko T; McGuire, Jimmy A

    2016-01-01

    The Asian common toad (Duttaphrynus melanostictus) is a human commensal species that occupies a wide variety of habitats across tropical Southeast Asia. We test the hypothesis that genetic variation in D. melanostictus is weakly associated with geography owing to natural and human-mediated dispersal facilitated by its commensal nature. Phylogenetic and population genetic analyses of mitochondrial and nuclear DNA sequence variation, and predictive species distribution modelling, unexpectedly recovered three distinct evolutionary lineages that differ genetically and ecologically, corresponding to the Asian mainland, coastal Myanmar and the Sundaic islands. The persistence of these three divergent lineages, despite ample opportunities for recent human-mediated and geological dispersal, suggests that D. melanostictus actually consists of multiple species, each having narrower geographical ranges and ecological niches, and higher conservation value, than is currently recognized. These findings also have implications for the invasion potential of this human commensal elsewhere, such as in its recently introduced ranges on the islands of Borneo, Sulawesi, Seram and Madagascar. PMID:26763213

  19. A new species of flea-toad (Anura: Brachycephalidae) from southern Atlantic Forest, Brazil.

    Science.gov (United States)

    Condez, Thais Helena; Monteiro, Juliane Petry De Carli; Comitti, Estevão Jasper; Garcia, Paulo Christiano De Anchietta; Amaral, Ivan Borel; Haddad, Célio Fernando Baptista

    2016-01-01

    We describe a new species of Brachycephalus that is morphologically similar to the flea-toads B. didactylus, B. hermogenesi, and B. pulex. The new species occurs from the sea level up to 1000 m and it is widely distributed throughout southern Atlantic Forest. Brachycephalus sulfuratus sp. nov. is distinguished from all of its congeners by the combination of the following characters: (1) small body size (SVL of adults: 7.4-8.5 mm for males and 9.0-10.8 mm for females); (2) "leptodactyliform" body; (3) pectoral girdle arciferal and less robust compared to the Brachycephalus species with "bufoniform" body; (4) procoracoid and epicoracoid fused with coracoid but separated from the clavicle by a large fenestrae; (5) toe I externally absent; toes II, III, IV, and V distinct; phalanges of toes II and V reduced; (6) skin smooth with no dermal ossifications; (7) in life, general background color brown with small dark-brown spots; skin of throat, chest, arms, and forearms with irregular yellow blotches; in ventral view, cloacal region of alive and preserved specimens surrounded by a dark-brown inverted v-shaped mark outlined with white; (8) advertisement call long, composed of a set of 4-7 high-frequency notes (6.2-7.2 kHz) repeated regularly. PMID:27394218

  20. The cane or marine toad, Rhinella marina (Anura, Bufonidae): two genetically and morphologically distinct species.

    Science.gov (United States)

    Acevedo, Aldemar A; Lampo, Margarita; Cipriani, Roberto

    2016-04-18

    Rhinella marina is a Neotropical toad that has been introduced widely worldwide. Its toxic effects to frog-eating predators threaten the native and domestic fauna of some regions where it has been introduced. Despite previous studies suggesting two genetically distinct cryptic species within R. marina, one east and one west of the Andes, its taxonomic status remained unresolved due to the absence of morphological complementary evidence. For the first time, data from two mitochondrial genes (ND3 and CR) and 23 morphometric landmarks are combined to evaluate the taxonomic status of this species. Our results support the hypothesis of two separate evolutionary lineages within R. marina and demonstrate that these lineages have significantly diverged in skull shape. We identified two distinct morphotypes, one eastern and one Andean western, with no overlapping morphospaces. The geographic pattern of genetic variation was consistent with a stable structured population with no evidence of recent demographic or geographic expansions. The concordance between the observed geographic patterns in morphometric and genic traits calls for the recognition of two species under R. marina name.

  1. keratinized nuptial spines are used for male combat in the emei moustache toad (leptobrachium boringii)

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    we describe the natural history and reproductive behaviour of the emei moustache toad (leptobrachium boringii)with an emphasis on the development of keratinized nuptial spines in males and document combat behaviour for the first time in this species.between february and march of 2011,19 female and 43 male l.boringii from mount emei unesco world heritage site,sichuan,china were observed throughout the breeding season.this species exhibits male-biased sexual size dimorphism (ssd)with limited evidence of paternal care (nest guarding by males).prior to the breeding season males grow 10-16 keratinized spines on their upper lip,which fall off once the season has ended.throughout the breeding season males construct and defend aquatic nests where they produce advertisement calls to attract females.during this time we documented 14 cases involving a total of 22 males where males used their moustaches for aggressive interaction.combat typically occurred at the beginning of the season when males would compete for a limited number of available nest sites.neither male body size,nor body condition significantly affects the outcome of an aggressive interaction,suggesting that size may not be the only factor influencing an individual's chance of victory.our evidence for male competition and aggression,along with observed paternal care are potential mechanisms to explain the evolution of male-biased ssd observed in this species.

  2. Phylogeography and demography of Guianan harlequin toads (Atelopus): diversification within a refuge.

    Science.gov (United States)

    Noonan, Brice P; Gaucher, Philippe

    2005-09-01

    We investigated the genetic structure of populations of Guianan harlequin toads (genus Atelopus) and their evolutionary affinities to extra-Guianan congeners. Phylogenetic analysis of mitochondrial cytochrome b (cyt b) and NADH dehydrogenase subunit 2 (ND2) gene sequences produced well-supported clades largely corresponding to the four recognized taxa in the Guianas (Atelopus spumarius hoogmoedi, Atelopus spumarius barbotini, Atelopus franciscus, and Atelopus flavescens). Our findings suggest that the Guianan A. spumarius represent distinct evolutionary lineages that merit distinction from Amazonian conspecifics, and that the status of A. flavescens and A. franciscus is somewhat less clear. Approximately 69% of the observed genetic variation is accounted for by differences between these four recognized taxa. Coalescent-based estimates of gene flow between taxa suggest that these lineages are largely isolated from one another. Negligible rates of migration between populations and significant divergence within such close proximity suggests that although the region inhabited by these taxa is almost entirely undisturbed, significant habitat heterogeneity exists as to have produced a remarkable diversification of Atelopus within the eastern Guiana Shield. These results contradict the commonly held view of the Guiana Shield as a 'refuge' whose stability during late Tertiary and Quaternary climatic fluctuations served as a biotic reservoir. Instead, we provide evidence that climatic fluctuations during this time had a diversifying effect within the Guianan region. PMID:16101771

  3. A new linearly-combined bi-exponential model for kinetic analysis of the isometric relaxation process of Bufo gastrocnemius under electric stimulation in vitro

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    There was a slow-relaxing tail of skeletal muscles in vitro upon the inhibition of Ca2+-pump by cyclopiazonic acid (CPA). Herein, a new linearly-combined bi-exponential model to resolve this slow-relaxing tail from the fast-relaxing phase was investigated for kinetic analysis of the isometric relaxation process of Bufo gastrocnemius in vitro, in comparison to the single exponential model and the classical bi-exponential model. During repetitive stimulations at a 2-s interval by square pulses of a 2-ms duration at 12 V direct currency (DC), the isometric tension of Bufo gastrocnemius was recorded at 100 Hz. The relaxation curve with tensions falling from 90% of the peak to the 15th datum before next stimulation was analyzed by three exponential models using a program in MATLAB 6.5. Both the goodness of fit and the distribution of the residuals for the best fitting supported the comparable validity of this new bi-exponential model for kinetic analysis of the relaxation process of the control muscles. After CPA treatment, however, this new bi-exponential model showed an obvious statistical superiority for kinetic analysis of the muscle relaxation process, and it gave the estimated rest tension consistent to that by experimentation, whereas both the classical bi-exponential model and the single exponential model gave biased rest tensions. Moreover, after the treatment of muscles by CPA, both the single exponential model and the classical bi-exponential model yielded lowered relaxation rates,nevertheless, this new bi-exponential model had relaxation rates of negligible changes except much higher rest tensions. These results suggest that this novel linearly-combined bi-exponential model is desirable for kinetic analysis of the relaxation process of muscles with altered Ca2+-pumping activity.

  4. Sexual dimorphism in baseline urinary corticosterone metabolites and their association with body-condition indices in a peri-urban population of the common Asian toad (Duttaphrynus melanostictus).

    Science.gov (United States)

    Narayan, Edward J; Gramapurohit, Narahari P

    2016-01-01

    Field endocrinology research through the quantification of glucocorticoids or stress hormones in free-living wildlife is crucial for assessing their physiological responses towards pervasive environmental changes. Urinary corticosterone metabolite (UCM) enzyme-immunoassay (EIA) has been validated for numerous amphibian species as a non-invasive measure of physiological stress. Body-condition indices (BCIs) have also been widely used in amphibians as an indirect measure of animal health. Field endocrinology research on amphibian species in Asia is limited. In this study, we validated a UCM EIA in a peri-urban sub-population of the common Asian toad (Duttaphrynus melanostictus) in Pune, Maharashtra, India. We determined the baseline levels of UCMs in male (n=39) and female (n=19) toads. Secondly, we used a standard capture handling protocol to quantify changes in UCMs during short-term captivity. We also determined BCIs in the male and female toads using Fulton's index (K) and residual condition index (RCI). The results showed that mean baseline levels of UCMs were significantly higher in male toads than in females. There was no significant change in mean levels of UCMs of males and females between capture and captivity (0-12h). This highlights plausible habituation of the species to the peri-urban environment. Associations between UCMs with BCIs (K and R) were positive in male toads but negative in females. In conclusion, our UCMs EIA can be applied with BCIs to assess health of the Asian toads. We also suggest that direct fitness parameters such as sperm and oocyte quality, reproductive ecology and immunocompetence measurements should be applied in combination with these conservation physiology tools to quantify the fitness consequences of pervasive environmental changes on native amphibians. PMID:26478192

  5. Breeding pond selection and movement patterns by eastern spadefoot toads (Scaphiopus holbrookii) in relation to weather and edaphic conditions.

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, Cathryn H. [USDA Forest Service, New Ellenton, SC (United States); Tanner, George W. [USDA Forest Service, New Ellenton, SC (United States)

    2004-08-31

    Cathryn H. Greenberg and George W. Tanner. 2004. Breeding pond selection and movement patterns by eastern spadefoot toads (Scaphiopus holbrookii) in relation to weather and edaphic conditions. J. Herp. 38(4):569-577. Abstract: Eastern Spadefoot Toads (Scaphiopus holbrookii) require fish-free, isolated, ephemeral ponds for breeding but otherwise inhabit the surrounding uplands, commonly xeric longleaf pine (Pinus palustris) wiregrass (Aristida beyrichiana). Hence both pond and upland conditions can potentially affect their breeding biology, and population persistence. Hardwood invasion due to fire suppression in sandhills could alter upland and pond suitability by higher hardwood density and increased transpiration. In this paper we explore breeding and neonatal emigration movements in relation to weather, hydrological conditions of ponds, and surrounding upland matrices. We use 9 years of data from continuous monitoring with drift fences and pitfall traps at 8 ephemeral ponds in 2 upland matrices: regularly-burned, savanna-like sandhills (n = 4), and hardwood-invaded sandhills (n = 4). Neither adult nor neonate captures differed between ponds within the 2 upland matrices, suggesting that they are tolerant of upland heterogeneity created by fire frequency. Explosive breeding occurred during 9 periods and in all seasons; adults were captured rarely otherwise. At a landscape-level rainfall, maximum change in barometric pressure, and an interaction between those 2 variables were significant predictors of explosive breeding. At a pond-level, rainfall, change in pond depth during the month prior to breeding, and days since a pond was last dry were significant predictors of adult captures. Transformation date, rather than weather, was associated with neonatal emigrations, which usually were complete within a week. Movement by first-captured adults and neonates was directional, but adult emigrations were apparently not always toward their origin. Our results suggest that

  6. Patterns of Genetic Variability in Island Populations of the Cane Toad (Rhinella marina) from the Mouth of the Amazon

    Science.gov (United States)

    Bessa-Silva, Adam Rick; Vallinoto, Marcelo; Sodré, Davidson; da Cunha, Divino Bruno; Hadad, Dante; Asp, Nils Edvin; Sampaio, Iracilda; Schneider, Horacio; Sequeira, Fernando

    2016-01-01

    The Amazonian coast has several unique geological characteristics resulting from the interaction between drainage pattern of the Amazon River and the Atlantic Ocean. It is one of the most extensive and sedimentologically dynamic regions of the world, with a large number of continental islands mostly formed less than 10,000 years ago. The natural distribution of the cane toad (Rhinella marina), one of the world’s most successful invasive species, in this complex Amazonian system provides an intriguing model for the investigation of the effects of isolation or the combined effects of isolation and habitat dynamic changes on patterns of genetic variability and population differentiation. We used nine fast-evolving microsatellite loci to contrast patterns of genetic variability in six coastal (three mainlands and three islands) populations of the cane toad near the mouth of the Amazon River. Results from Bayesian multilocus clustering approach and Discriminant Analyses of Principal Component were congruent in showing that each island population was genetically differentiated from the mainland populations. All FST values obtained from all pairwise comparisons were significant, ranging from 0.048 to 0.186. Estimates of both recent and historical gene flow were not significantly different from zero across all population pairs, except the two mainland populations inhabiting continuous habitats. Patterns of population differentiation, with a high level of population substructure and absence/restricted gene flow, suggested that island populations of R. marina are likely isolated since the Holocene sea-level rise. However, considering the similar levels of genetic variability found in both island and mainland populations, it is reliable to assume that they were also isolated for longer periods. Given the genetic uniqueness of each cane toad population, together with the high natural vulnerability of the coastal regions and intense human pressures, we suggest that these

  7. On-line comprehensive two-dimensional normal-phase liquid chromatography×reversed-phase liquid chromatography for preparative isolation of toad venom.

    Science.gov (United States)

    Li, Jia-Fu; Fang, Hua; Yan, Xia; Chang, Fang-Rong; Wu, Zhen; Wu, Yun-Long; Qiu, Ying-Kun

    2016-07-22

    An on-line comprehensive preparative two-dimensional normal-phase liquid chromatography×reversed-phase liquid chromatography (2D NPLC×RPLC) system was constructed with a newly developed vacuum evaporation assisted adsorption (VEAA) interface, allowing fast removal of NPLC solvent in the vacuum condition and successfully solving the solvent incompatibility problem between NPLC and RPLC. The system achieved on-line solvent exchange within the two dimensions and its performance was illustrated by gram-scale isolation of crude extract from the venom of Bufo bufo gargarizans. Within separation time of ∼20h, 19 compounds were obtained with high purity in a single run. With the VEAA interface, the 2D system exhibited apparent advantages in separation efficiency and automation compared with conventional methods, indicating its promising application in the routine separation process for complicated natural products. PMID:27328884

  8. Widespread occurrence in frogs and toads of skin compounds interacting with the ouabain site of Na+, K+-ATPase.

    Science.gov (United States)

    Flier, J; Edwards, M W; Daly, J W; Myers, C W

    1980-05-01

    Amphibians of the family Bufonidae contain high levels of skin compounds that both inhibit Na+- and K+-dependent adenosinetriphosphatase and antagonize the binding of ouabain to the enzyme. In species of Bufo and Atelopus, these compounds are relatively nonpolar bufodienolides, whereas Dendrophryniscus and Melanophryniscus contain more polar compounds of unknown structure. Skin extracts from 30 of 48 species of frogs representing an additional eight families contained relatively low levels of compounds that inhibit binding of ouabain to Na+,K+-adenosinetriphosphatase. The widespread occurrence of low levels of inhibitory compounds is consonant with the role for these compounds as physiological regulators of Na+,K+-adenosinetriphosphatase in amphibian skin; high levels in the Bufonidae probably also serve as a defense against some predators. PMID:6245447

  9. Malformations and mortality in the Asian Common Toad induced by exposure to pleurolophocercous cercariae (Trematoda: Cryptogonimidae).

    Science.gov (United States)

    Jayawardena, Uthpala A; Tkach, Vasyl V; Navaratne, Ayanthi N; Amerasinghe, Priyanie H; Rajakaruna, Rupika S

    2013-06-01

    Malformations and increased mortality due to infection by the digenetic trematode, Riberioa ondatrae have been reported for many species of amphibians. Severe malformations have also been reported in the Common Hourglass Tree Frog, Polypedates cruciger induced by pleurolophocercous cercariae in Sri Lanka in addition to the changes in the behaviour, development and survival of the host. We exposed pre-limb bud stage tadpoles (Gosner stages 25-26) of the Asian Common Toad, Duttaphrynus melanostictus to the same pleurolophocercous type cercariae under laboratory conditions. Molecular and morphological identification showed that these cercariae belonged Acanthostomum burminis infecting freshwater snakes as definitive hosts. These cercariae induced malformations (27.8%) and reduced survival to metamorphosis (53.8%). The magnitude of the effects increased with the dose of cercariae. Types of malformations were mainly axial, such as scoliosis and kyphosis. Severe limb malformations such as extra or missing limbs as reported for amphibians exposed to R. ondatrae were not observed in the D. melanostictus. Same authors reported a higher percentage of malformations previously when P. cruciger was exposed to the cercariae A. burminis compared to D. melanostictus. However, tadpoles of D. melanostictus, which are smaller compared to those of P. cruciger, experienced higher mortality than P. cruciger tadpoles. Trematode induced malformations and mortality in amphibians are highly variable and depend on multiple factors such as host species differences such as resistance to infection and tolerance, life-history characteristics such as size at metamorphosis and length of the metamorphosis period, and other factors such as size of the amphibian at the time of trematode exposure. PMID:23353759

  10. Spitzer Observations of Var Her 04: Possible Detection of Dust Formation in a Super-Outbursting TOAD

    CERN Document Server

    Ciardi, D R; Hoard, D W; Howell, S B; Van Belle, G T; Ciardi, David R.; Wachter, Stefanie; Howell, Steve B.; Belle, Gerard T. van

    2006-01-01

    We present four MIPS (24 \\micron) and two IRAC (3.6, 4.5, 5.8, and 8.0 \\micron) Spitzer observations of the newly discovered Tremendous Outburst Amplitude Dwarf nova (TOAD) Var Her 04 during decline from super-outburst. The four MIPS observations span 271 days and the two IRAC observations span 211 days. Along the line-of-sight to Var Her 04, there is a foreground M-star within 1\\arcsec of the variable; as a result, all of the Spitzer photometry presented in this paper is a blend of the foreground M-star and Var Her 04. We estimate the quiescent level of the TOAD to be $\\Delta V=4-5$ magnitudes below that of the M-star. Based upon the spectral energy distribution and the 2MASS colors, we find the M-star to be an M3.5V dwarf at a distance of 80-130 pc. Based upon its outburst amplitude and quiescent apparent magnitude, we estimate the distance to Var Her 04 to be 200-400 pc, suggesting that the line-of-sight foreground star is physically unrelated to the cataclysmic variable. All of the Spitzer photometry is c...

  11. Influence of sprint speed and body size on predator avoidance in New Mexican spadefoot toads (Spea multiplicata).

    Science.gov (United States)

    Arendt, Jeffrey David

    2009-03-01

    Predator-prey interactions play an important role in community dynamics and may be important for promoting genetic diversification. Diversification may be especially important when prey species have multiple anti-predator strategies available, but these strategies conflict with each other. For example, rapid sprint speed and large size are both thought to decrease vulnerability to many predators. A physiological trade-off between swimming speed and growth rate has been documented in many aquatic species and, as a result, individual genotypes may employ one strategy or the other, but not both. Although rapid sprint speed is often assumed to decrease vulnerability to predators, this has only rarely been tested. Here I provide evidence that both rapid sprint speed and large size in tadpoles of the New Mexico spadefoot toad (Spea multiplicata) decreases predation risk from carnivore morphs of its congener the Great Plains spadefoot toad (Spea bombifrons). Such conflicts, coupled with spatio-temporal variation in predation pressure, may be important in maintaining genetic variation for trade-offs.

  12. Acute toxicity of arsenic and oxidative stress responses in the embryonic development of the common South American toad Rhinella arenarum.

    Science.gov (United States)

    Mardirosian, Mariana Noelia; Lascano, Cecilia Inés; Ferrari, Ana; Bongiovanni, Guillermina Azucena; Venturino, Andrés

    2015-05-01

    Arsenic (As), a natural element of ecological relevance, is found in natural water sources throughout Argentina in concentrations between 0.01 mg/L and 15 mg/L. The autochthonous toad Rhinella arenarum was selected to study the acute toxicity of As and the biochemical responses elicited by the exposure to As in water during its embryonic development. The median lethal concentration (LC50) value averaged 24.3 mg/L As and remained constant along the embryonic development. However, As toxicity drastically decreased when embryos were exposed from heartbeat-stage on day 4 of development, suggesting the onset of detoxification mechanisms. Given the environmental concentrations of As in Argentina, there is a probability of exceeding lethal levels at 1% of sites. Arsenic at sublethal concentrations caused a significant decrease in the total antioxidant potential but generated an increase in endogenous glutathione (GSH) content and glutathione S-transferase (GST) activity. This protective response might prevent a deeper decline in the antioxidant system and further oxidative damage. Alternatively, it might be linked to As conjugation with GSH for its excretion. The authors conclude that toad embryos are more sensitive to As during early developmental stages and that relatively high concentrations of this toxic element are required to elicit mortality, but oxidative stress may be an adverse effect at sublethal concentrations.

  13. MEASUREMENT OF REGIONAL BONE BLOOD FLOW IN THE CANINE MANDIBULAR RAMUS USING RADIOLABELLED TOAD RED BLOOD CELLS

    Institute of Scientific and Technical Information of China (English)

    毛驰; 王翰章

    1994-01-01

    Toad red blood cells were used to measure regional bone blood flow in the canine mandibular ramus.The blood cells were labelled with sodium pertechnetate and fixed in 10% formalin;they were 22×15 μm in size and had a specific gravity close to that of dog red blood cells.These cells had no discernible effect on systemic hemody-namics after injection,did not agglutinate,were well mixed and evenly distributed throughout the body,and were completely extracted in one circulation through the mandible.The mandibular ramus was divided into six regions,and the blood flow rates in each were found to be similar to those reported in previous studies with radiolabelled carbonized,microspheres.Furthermore,the blood flow distribution pattern of the mandibular ramus determined in this study was identical to that of our previous study using the bone-seeking radionuclide method.We suggest that radiolabelled toad red blood cells are an ideal marker for measuring regional blood flow in the canine mandible.

  14. Estudio morfométrico sobre el desarrollo y evolución de las glándulas tiroides durante la metamorfosis de Bufo arenarum

    Directory of Open Access Journals (Sweden)

    Miranda, Leandro Andrés

    1996-01-01

    Full Text Available Se ha estudiado el desarrollo y la evolución de las glándulas tiroideas durante la morfogénesis de Bufo arenarum. Usando diferentes parámetros morfométricos, hemos relacionado el crecimiento y desarrollo larval con el desarrollo de las glándulas tiroideas. Se observó que la longitud total, el peso de las larvas, el volumen glandular tiroideo y el diámetro folicular, aumentan hasta el estadio XV (fin de la prometamorfosis, mientras que el número de folículos y la altura de las células foliculares tiroideas se incrementan hasta el estadio XVII (mitad del clímax metamórfico. Todos estos parámetros disminuyeron considerablemente durante el clímax metamórfico mientras que en animales postmetamórficos se observó un incremento en los valores registrados. En base a los resultados obtenidos concluimos que hay un período de síntesis y almacenamiento de hormonas tiroideas durante el crecimiento larval y un segundo período caracterizado por la liberación de hormonas tiroideas hacia el final de la prometamorfosis y durante el clímax metamórfico. We studied the development and evolution of thyroid glands during Bufo arenarum morphogenesis. Using different morphometric parameters we related larval growth and metamorphosis with thyroid glands development We observed that total length, larval weight, thyroid gland volume and follicle diameter increased until stage XV (end of prometamorphosis, meanwhile the number of follicles and follicle cell height increased until stage XVII (midclimax. All these parameters decreased during metamorphic climax and an increase was observed in postmetamorphic animals. Our results lead us to conclude that during larval growth there is a period of synthesis and store of thyroid hormones. There is a second period characterized by thyroid hormones release during the end of prometamorphosis and metamorphic climax.

  15. Genotoxicity of the Herbicide Butachlor on Bufo gargarizans gargarizans Tadpoles%丁草胺对中华大蟾蜍蝌蚪的遗传毒性

    Institute of Scientific and Technical Information of China (English)

    林玲; 姚丹; 钟碧瑾; 房振华; 王楠楠; 耿艳; 耿宝荣

    2009-01-01

    以中华大蟾蜍(Bufo gargarizans gargarizans)蝌蚪为研究对象,采用微核实验和碱性单细胞凝胶电泳法(又称彗星实验,SCGE)检测不同质量浓度(0.1,0.2,0.3,0.4 mg/L)的丁草胺溶液对中华大蟾蜍蝌蚪红细胞的遗传毒性.结果表明:在实验室条件下,丁草胺质量浓度越高,蝌蚪红细胞的微核率和核异常率越显著.经丁草胺溶液处理24 h,蝌蚪红细胞的细胞损伤率及DNA损伤程度(彗星DNA长宽比)出现极显著的提高,并与丁草胺质量浓度呈显著的线性关系.研究表明丁草胺对两栖动物具有遗传毒性作用,同时也说明微核实验和碱性单细胞凝胶电泳法是检测环境污染对两栖动物遗传毒性的合适方法.%Micro-nuclear test and the alkaline single-cell gel electrophoresis assay (SCGE) or comet assay was performed to examine the genotoxicity of butachlor on erythro-cytes of Bufo gargarizans gargarizans tadpoles exposed to increasing concentration of the tested substance (0.1,0.2,0.3,0.4 mg/L). The results showed that both micro-nuclear frequency and nuclear abnormity frequency were significantly increased with the increasing concentration of butachlor in laboratory condition. Tadpoles treated for 24 h had significant, dose-responsive increases in the levels of DNA damage, as measured by the mean DNA length: width ratio. There were strong linear correlations between cells damage frequency, the mean DNA damage (length-to-width ratios) and the concentrations of butachlor. The results of this study indicate that butachlor produce genotoxicity in amphibians, and that using micro-nuclear test and SCGE may be useful for measuring DNA damage in tadpoles exposed in the field.

  16. Cyclic AMP-and beta-agonist-activated chloride conductance of a toad skin epithelium.

    Science.gov (United States)

    Willumsen, N J; Vestergaard, L; Larsen, E H

    1992-04-01

    1. The control by intracellular cyclic AMP and beta-adrenergic stimulation of chloride conductance was studied in toad skin epithelium mounted in a chamber on the stage of an upright microscope. Impalement of identified principal cells from the serosal side with single-barrelled conventional or double-barrelled Cl(-)-sensitive microelectrodes was performed at x500 magnification. For blocking the active sodium current 50 microM-amiloride was present in the mucosal bath. 2. When clamped at transepithelial potential difference V = 0 mV, the preparations generated clamping currents of 0.9 +/- 1 microA/cm2 (mean +/- S.E.M.; number of observations n = 55). The intracellular potential of principal cells (Vb) was -96 +/- 2 mV with a fractional resistance of the basolateral membrane (fRb) of 0.016 +/- 0.003 (n = 54), and an intracellular Cl- activity of 40 +/- 2 mM (n = 24). 3. At V = 0 mV, serosal application of a cyclic AMP analogue, dibutyryl cyclic AMP (500 microM) or a beta-adrenergic agonist, isoprenaline (5 microM) resulted in a sixfold increase in transepithelial Cl- conductance identified by standard 36Cl- tracer technique. 4. The clamping current at V = 0 mV was unaffected by cyclic AMP (short-circuit current Isc = 0.1 +/- 0.3 microA/cm2, n = 16) indicating that subepidermal Cl(-)-secreting glands are not functioning in our preparations obtained by collagenase treatment. 5. Cyclic AMP- or isoprenaline-induced chloride conductance (Gcl) activation (V = 0 mV) was not reflected in membrane potential and intracellular Cl- activity in principal cells. Intracellular chloride activity was constant at approximately 40 mM at membrane potentials between -90 and -100 mV. Therefore, it can be concluded that the principal cells are not contributing to activated Cl- currents. 6. At V = -100 mV where the voltage-dependent chloride conductance of mitochondria-rich (MR) cells was already fully activated, GCl was unaffected by cyclic AMP or isoprenaline. The major effect of these

  17. Quality Assessment of Serially Ultradiluted and Agitated Drug Digitalis purpurea by Emission Spectroscopy and Clinical Analysis of Its Effect on the Heart Rate of Indian Bufo melanostictus

    Directory of Open Access Journals (Sweden)

    Anup Sharma

    2013-01-01

    Full Text Available The investigation of ultradiluted (homeopathic drugs is extremely interesting and challenging, and from that point of view this study shows novelty. A study of in vivo changes in heart rate of the Indian Bufo melanostictus caused by commercially available serially ultra-diluted and agitated extract of Digitalis purpurea has been tried in order to understand their pharmacological role. RR interval (of ECG was compared after intraperitoneal administration of serially diluted and agitated Digitalis purpurea extract, diluent rectified spirit, and Digoxin in anesthetized animals. The study revealed statistically significant changes in the heart rate after application of these drugs except in case of Digoxin and the 200th serial dilution of Digitalis purpurea. The duration of RR intervals after application of the drugs was corroborative of the effect of Digoxin and Digitalis purpurea extract up to 30th dilution. Emission spectra were obtained for the experimental ultra-diluted Digitalis purpurea extract and Digoxin to identify and characterize them. The observed RR pattern and emission spectra show an association. The quality assessment of the commercial ultra-diluted organic drugs obtained from natural products may be initiated by monitoring in vivo studies on animal models.

  18. Proton pump activity is required for active uptake of chloride in isolated amphibian skin exposed to freshwater

    DEFF Research Database (Denmark)

    Jensen, Lars Jørn; Willumsen, Niels J.; Larsen, Erik Hviid

    2002-01-01

    Net proton secretion and unidirectional chloride fluxes were measured in isolated skin of toads (Bufo bufo) and frogs (Rana esculenta) mounted in an Ussing chamber and exposed to a Ringer's solution on the serosal side and a freshwater-like solution (1-3 mM Cl-) on the external side. Active proto...

  19. A Mathematical Model of Solute Coupled Water Transport in Toad Intestine Incorporating Recirculation of the Actively Transported Solute

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Sørensen, Jakob Balslev; Sørensen, Jens Nørkær

    2000-01-01

    those of tight junction and interspace basement membrane by convection-diffusion. With solute permeability of paracellular pathway large relative to paracellular water flow, the paracellular flux ratio of the solute (influx/outflux) is small (2-4) in agreement with experiments. The virtual solute...... back into lis, i.e., the solute would have to be recirculated. With input variables from toad intestine (Nedergaard, S., E.H. Larsen, and H.H. Ussing, J. Membr. Biol. 168:241-251), computations predict that 60-80% of the pumped flux stems from serosal bath in agreement with the experimental estimate...... of the recirculation flux. Robust solutions are obtained with realistic concentrations and pressures of lis, and with the following features. Rate of fluid absorption is governed by the solute permeability of mucosal membrane. Maximum fluid flow is governed by density of pumps on lis-membranes. Energetic efficiency...

  20. A new species of Paracapillaria (Nematoda: Capillariidae) from the intestine of the toad Duttaphrynus melanostictus (Anura) from the Malayan Peninsula.

    Science.gov (United States)

    Moravec, Frantisek; Modrý, David; Jirků, Miloslav

    2007-08-01

    A new species of parasitic nematode, Paracapillaria malayensis n. sp. (Capillariidae), is described from the small intestine of the toad Duttaphrynus melanostictus imported from the Malayan Peninsula to the Czech Republic. The new species differs from the only other congeneric species, Paracapillaria spratti, mainly in the shape and structure of the spicular proximal end (with a lobular rim), smaller eggs (45-51 x 21-24 microm), longer spicule (336 microm), and the number (37-38) of stichocytes in gravid females; whereas P. spratti parasitizes frogs of the Microhylidae in Papua New Guinea, P. malayensis is a parasite of Bufonidae in the Malayan Peninsula. Other Paracapillaria spp. are parasites of fishes, birds, or mammals and they mostly differ from P. malayensis in the structure of eggs and some other morphological features. PMID:17918374

  1. Immunohistochemical localization of cathepsin D and a possible role of melanocytes during tail resorption in tadpoles of a tropical toad.

    Science.gov (United States)

    Mahapatra, Cuckoo; Mahapatra, Pravati Kumari

    2012-07-01

    Programmed cell death during anuran tail resorption is primarily brought about by apoptosis. Cathepsin D, a lysosomal aspartyl protease, is involved in the death of tail tissues. Thus, anuran tail resorption presents an ideal model to study cathepsin-mediated cell death during vertebrate development. Present study describes the trend of specific activity of cathepsin D in the tail of different developmental stages and immunohistochemical localization of cathepsin D in the tail tissues of the common Asian toad, Duttaphrynus melanostictus. Cathepsin D was involved in programmed cell death in epidermis, muscle, spinal cord, and blood cells in the resorbing tail. Interestingly, it was also involved in the pre-resorbing tail before visible tail resorption which indicates initiation of cell death even before actually the tail resorbs. Melanocytes were found to be one of the causative agents in degrading tail tissues and were associated with the degradation of muscle, epidermis and spinal cord of the resorbing tail. PMID:22505219

  2. Cadmium-induced toxicity on larvae of the common Asian toad Duttaphrynus melanostictus (Schneider 1799): evidence from empirical trials.

    Science.gov (United States)

    Ranatunge, R A A R; Wijesinghe, M R; Ratnasooriya, W D; Dharmarathne, H A S G; Wijesekera, R D

    2012-07-01

    This paper investigates the toxicity of cadmium (Cd) on young stages of the common Asian toad Duttaphrynus melanostictus (Schneider 1799). Signs of acute toxicity were evident in tadpoles repeatedly exposed to five concentrations ranging from 0.002 to 2 mg L(-1)of Cd which included environmentally relevant levels. Mortality at concentrations of 0.02 mg L(-1) and above was enhanced from 2 % at 0.02 mg L(-1) to 100 % at 1 mg L(-1), in a dose-dependent manner. Significant growth impairment was evident at 0.20 mg L(-1) with the larvae being markedly smaller. Delayed metamorphosis and retarded swimming were also observed. Therefore levels of Cd recorded in some freshwater bodies in Sri Lanka (e.g. 0.2 mg L(-1)) may be detrimental to the young stages of D. melanostictus. PMID:22526988

  3. Checklist and Simple Identification Key for Frogs and Toads from District IV of The MADA Scheme, Kedah, Malaysia.

    Science.gov (United States)

    Jaafar, Ibrahim; Chai, Teoh Chia; Sah, Shahrul Anuar Mohd; Akil, Mohd Abdul Muin Md

    2009-12-01

    A survey was conducted to catalogue the diversity of anurans in District IV of the Muda Agriculture Development Authority Scheme (MADA) in Kedah Darul Aman, Malaysia, from July 1996 to January 1997. Eight species of anurans from three families were present in the study area. Of these, the Common Grass Frog (Fejevarya limnocharis) was the most abundant, followed by Mangrove Frog (Fejevarya cancrivora), Long-legged Frog (Hylarana macrodactyla), and Common Toad (Duttaphrynus melanostictus). Puddle Frog (Occidozyga lima), Taiwanese Giant Frog (Hoplobatrachus rugulosus), and Banded Bullfrog (Kaluola pulchra) were rare during the sampling period, and only one Paddy Frog (Hylarana erythraea) was captured. A simple identification key for the anurans of this area is included for use by scientists and laymen alike. PMID:24575178

  4. Changes of body fluid and hematology in toad and their rehabilitation following intermittent exposure to simulated high altitude

    Science.gov (United States)

    Biswas, H. M.; Boral, M. C.

    1986-06-01

    Three groups of adult male toads were exposed intermittently in a decompression chamber for a daily period of 4 and 8 hours at a time for 6 consecutive days to an “altitude” of 12,000; 18,000 and 24,000 feet (3658; 5486; 7315 m) respectively. Most of the exposed animals were sacrificed immediately after the last exposure, but only a few animals experiencing 8 hours of exposure were sacrificed after a further 16 hours of exposure at normal atmospheric pressure. Eight hours of daily exposure for 6 days causes a decrease of body fluids and an increase of hematological parameters in all the altitude exposed animals compared with to the changes noted in the animals having 4 hours of daily exposure for 6 days at the same altitude levels. The animals that were exposed to pressures equivalent to altitudes of 12,000 and 18,000 feet daily for 8 hours were found to return nearly to their normal body fluids and hematological balance after 16 hours of exposure to normal atmospheric pressure, whereas the animals exposed for a similar period at an equivalent 24,000 feet failed to get back their normal balance of body fluids and hematology after 16 hours of exposure at normal atmospheric pressure. The present experiment shows that the body weight loss and changes of body fluid and hematological parameters in the toad after exposure to simulated high altitude are due not only to dehydration, but suggest that hypoxia may also have a role.

  5. Toad radiation reveals into-India dispersal as a source of endemism in the Western Ghats-Sri Lanka biodiversity hotspot

    Directory of Open Access Journals (Sweden)

    Bossuyt Franky

    2009-06-01

    Full Text Available Abstract Background High taxonomic level endemism in the Western Ghats-Sri Lanka biodiversity hotspot has been typically attributed to the subcontinent's geological history of long-term isolation. Subsequent out of – and into India dispersal of species after accretion to the Eurasian mainland is therefore often seen as a biogeographic factor that 'diluted' the composition of previously isolated Indian biota. However, few molecular studies have focussed on into-India dispersal as a possible source of endemism on the subcontinent. Using c. 6000 base pairs of mitochondrial and nuclear DNA, we investigated the evolutionary history and biogeography of true toads (Bufonidae, a group that colonized the Indian Subcontinent after the Indo-Asia collision. Results Contrary to previous studies, Old World toads were recovered as a nested clade within New World Bufonidae, indicating a single colonization event. Species currently classified as Ansonia and Pedostibes were both recovered as being non-monophyletic, providing evidence for the independent origin of torrential and arboreal ecomorphs on the Indian subcontinent and in South-East Asia. Our analyses also revealed a previously unrecognized adaptive radiation of toads containing a variety of larval and adult ecomorphs. Molecular dating estimates and biogeographic analyses indicate that the early diversification of this clade happened in the Western Ghats and Sri Lanka during the Late Oligocene to Early Miocene. Conclusion Paleoclimate reconstructions have shown that the Early Neogene of India was marked by major environmental changes, with the transition from a zonal- to the current monsoon-dominated climate. After arrival in the Western Ghats-Sri Lanka hotspot, toads diversified in situ, with only one lineage able to successfully disperse out of these mountains. Consequently, higher taxonomic level endemism on the Indian Subcontinent is not only the result of Cretaceous isolation, but also of invasion

  6. Polyphyly of Asian Tree Toads, Genus Pedostibes Günther, 1876 (Anura: Bufonidae), and the Description of a New Genus from Southeast Asia

    OpenAIRE

    Kin Onn Chan; L Lee Grismer; Anil Zachariah; Brown, Rafe M.; Robin Kurian Abraham

    2016-01-01

    The Asian Tree Toad genus Pedostibes, as currently understood, exhibits a conspicuously disjunct distribution, posing several immediate questions relating to the biogeography and taxonomy of this poorly known group. The type species, P. tuberculosus and P. kempi, are known only from India, whereas P. hosii, P. rugosus, and P. everetti are restricted to Southeast Asia. Several studies have shown that these allopatric groups are polyphyletic, with the Indian Pedostibes embedded within a primari...

  7. Role of the endogenous kallikrein-kinin system in modulating vasopressin-stimulated water flow and urea permeability in the toad urinary bladder.

    OpenAIRE

    Carvounis, C P; Carvounis, G; Arbeit, L A

    1981-01-01

    This study investigates the endogenous kallikrein-kinin system's role as a modulator of vasopressin action in the toad urinary bladder. Kalli-krein inhibition by aprotinin, which results in decreased kinin production, significantly increased both vasopressin and 8-Br-cyclic (c) AMP-stimulated water flow. Kinin potentiation by the kininase II inhibitor captopril (SQ 14225) significantly decreased vasopressin and 8-Br-cAMP-stimulated water flow. In contrast to water flow, vasopressin-stimulated...

  8. Polyphyly of Asian Tree Toads, Genus Pedostibes Günther, 1876 (Anura: Bufonidae), and the Description of a New Genus from Southeast Asia.

    Science.gov (United States)

    Chan, Kin Onn; Grismer, L Lee; Zachariah, Anil; Brown, Rafe M; Abraham, Robin Kurian

    2016-01-01

    The Asian Tree Toad genus Pedostibes, as currently understood, exhibits a conspicuously disjunct distribution, posing several immediate questions relating to the biogeography and taxonomy of this poorly known group. The type species, P. tuberculosus and P. kempi, are known only from India, whereas P. hosii, P. rugosus, and P. everetti are restricted to Southeast Asia. Several studies have shown that these allopatric groups are polyphyletic, with the Indian Pedostibes embedded within a primarily South Asian clade of toads, containing the genera Adenomus, Xanthophryne, and Duttaphrynus. Southeast Asian Pedostibes on the other hand, are nested within a Southeast Asian clade, which is the sister lineage to the Southeast Asian river toad genus Phrynoidis. We demonstrate that Indian and Southeast Asian Pedostibes are not only allopatric and polyphyletic, but also exhibit significant differences in morphology and reproductive mode, indicating that the Southeast Asian species' are not congeneric with the true Pedostibes of India. As a taxonomic solution, we describe a new genus, Rentapia gen. nov. to accommodate the Southeast Asian species.

  9. Polyphyly of Asian Tree Toads, Genus Pedostibes Günther, 1876 (Anura: Bufonidae), and the Description of a New Genus from Southeast Asia.

    Science.gov (United States)

    Chan, Kin Onn; Grismer, L Lee; Zachariah, Anil; Brown, Rafe M; Abraham, Robin Kurian

    2016-01-01

    The Asian Tree Toad genus Pedostibes, as currently understood, exhibits a conspicuously disjunct distribution, posing several immediate questions relating to the biogeography and taxonomy of this poorly known group. The type species, P. tuberculosus and P. kempi, are known only from India, whereas P. hosii, P. rugosus, and P. everetti are restricted to Southeast Asia. Several studies have shown that these allopatric groups are polyphyletic, with the Indian Pedostibes embedded within a primarily South Asian clade of toads, containing the genera Adenomus, Xanthophryne, and Duttaphrynus. Southeast Asian Pedostibes on the other hand, are nested within a Southeast Asian clade, which is the sister lineage to the Southeast Asian river toad genus Phrynoidis. We demonstrate that Indian and Southeast Asian Pedostibes are not only allopatric and polyphyletic, but also exhibit significant differences in morphology and reproductive mode, indicating that the Southeast Asian species' are not congeneric with the true Pedostibes of India. As a taxonomic solution, we describe a new genus, Rentapia gen. nov. to accommodate the Southeast Asian species. PMID:26788854

  10. Polyphyly of Asian Tree Toads, Genus Pedostibes Gunther, 1876 (Anura: Bufonidae, and the Description of a New Genus from Southeast Asia.

    Directory of Open Access Journals (Sweden)

    Kin Onn Chan

    Full Text Available The Asian Tree Toad genus Pedostibes, as currently understood, exhibits a conspicuously disjunct distribution, posing several immediate questions relating to the biogeography and taxonomy of this poorly known group. The type species, P. tuberculosus and P. kempi, are known only from India, whereas P. hosii, P. rugosus, and P. everetti are restricted to Southeast Asia. Several studies have shown that these allopatric groups are polyphyletic, with the Indian Pedostibes embedded within a primarily South Asian clade of toads, containing the genera Adenomus, Xanthophryne, and Duttaphrynus. Southeast Asian Pedostibes on the other hand, are nested within a Southeast Asian clade, which is the sister lineage to the Southeast Asian river toad genus Phrynoidis. We demonstrate that Indian and Southeast Asian Pedostibes are not only allopatric and polyphyletic, but also exhibit significant differences in morphology and reproductive mode, indicating that the Southeast Asian species' are not congeneric with the true Pedostibes of India. As a taxonomic solution, we describe a new genus, Rentapia gen. nov. to accommodate the Southeast Asian species.

  11. Large-scale habitat associations of four desert anurans in Big Bend National Park, Texas

    Science.gov (United States)

    Dayton, G.H.; Jung, R.E.; Droege, S.

    2004-01-01

    We used night driving to examine large scale habitat associations of four common desert anurans in Big Bend National Park, Texas. We examined association of soil types and vegetation communities with abundance of Couch's Spadefoots (Scaphiopus couchii), Red-spotted Toads (Bufo punctatus), Texas Toads (Bufo speciosus), and Western Green Toads (Bufo debilis). All four species were disproportionately associated with frequently inundated soils that are relatively high in clay content. Bufo punctatus was associated with rocky soil types more frequently than the other three species. Association between all four species and vegetation types was disproportionate in relation to availability. Bufo debilis and Bufo punctatus were associated with creosote and mixed scrub vegetation. Bufo speciosus and Scaphiopus couchii were associated with mesquite scrub vegetation. Bufo debilis, Scaphiopus couchii, and B. speciosus were more tightly associated with specific habitat types, whereas B. punctatus exhibited a broader distribution across the habitat categories. Examining associations between large-scale habitat categories and species abundance is an important first step in understanding factors that influence species distributions and presence-absence across the landscape.

  12. Detection of the emerging amphibian pathogens Batrachochytrium dendrobatidis and ranavirus in Russia

    Science.gov (United States)

    Reshetnikov, Andrey N.; Chestnut, Tara E.; Brunner, Jesse L.; Charles, Kaylene M.; Nebergall, Emily E.; Olson, Deanna H.

    2014-01-01

    In a population of the European common toad Bufo bufo from a rural pond in the region of Lake Glubokoe Regional Reserve in Moscow province, Russia, unexplained mass mortality events involving larvae and metamorphs have been observed over a monitoring period of >20 yr. We tested toads from this and a nearby site for the emerging amphibian pathogens Batrachochytrium dendrobatidis (Bd) and ranavirus (Rv). Both pathogens were detected, and at the rural pond site, with the above-noted losses and decline in toad breeding success, 40% of B. bufo metamorphs were Bd positive, 46% were Rv positive and 20% were co-infected with both pathogens. Toad metamorphs from a neighbouring water body were also Bd and Rv positive (25 and 55%, respectively). This is the first confirmation of these pathogens in Russia. Questions remain as to the origins of these pathogens in Russia and their roles in documented mass mortality events.

  13. Feeding pattern and use of reproductive habitat of the Striped toad Rhinella crucifer (Anura: Bufonidae from Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Rodrigo B. Ferreira

    2009-12-01

    Full Text Available Diet composition, foraging mode, and using of reproductive habitat of Rhinella crucifer was studied in an artificial pond in Espírito Santo, Brazil. The favored substrate was leaf litter, followed by Cyperaceae/Poaceae. Calling sites, preferred for 23.3 % (n = 7 of the observed toads, were within the water, with only the head not submerged. We analyzed a total of 61 specimens, mainly males (98.5% male and 1.5% female. Seven categories of prey were found in the stomach contents: Coleoptera, Hymenoptera (Formicidae, Isoptera, Lepidoptera, Orthoptera, Gastropoda (Mollusca, Opilionida (Arachnida. Our studies indicate that the diet of Rhinella crucifer consists mainly of terrestrial colonial arthropods. Formicidae was the predominant food item in frequency of occurrence, number of prey and weight. Isoptera and Coleoptera were also relevant in terms of weight. Neither large ontogenetic dietary nor seasonal shifts were observed in the population studied. Our results suggest that no intraspecific food resource partitioning occurs in adult or juveniles. Rhinella crucifer adults avoid competition inhabiting different home range habitats and seem to be ant-specialist with a wide foraging mode.

  14. The effect of detergents pollution on growth of Bufo melanostictus embryo and tadpoles%生活污水对黑眶蟾蜍胚胎及蝌蚪发育的影响

    Institute of Scientific and Technical Information of China (English)

    王立; 徐剑

    2012-01-01

    两栖类蝌蚪发育对环境污染比较敏感,可用于对环境污染的生物监测.观察了黑眶蟾蜍胚胎及蝌蚪在生活污水中的发育情况,可以看出随着污染浓度增大,表现为胚胎及蝌蚪死亡率增加,发育时期延长,蝌蚪的体重增加延迟,体长发育延迟,尾部萎缩过程延迟.结果表明:黑眶蟾蜍胚胎在生活污水浓度达到10%为致死量,8%为半致死量.蝌蚪在生活污水中浓度达到80%为致死量,60%为半致死量,50%对发育明显影响,甚至致畸,50%对体长和尾长的影响最为明显.%The growth of amphibian tadpoles are sensitive to environmental pollution, which can be used for the biological monitoring of environmental pollution. Observing embryos and Bufo melanostictus tadpoles in a detergent-based domestic wastewater, with the increasing concentration, showing an increase in mortality, there are three aspects of development which is growth of the extension period, tadpole weight, body length and tail length affected. The results showed that the lethal dose of Bufo melanostictus embryos in sewage concentration is 10%, the semi-lethal dose of Bufo melauostictus embryos is 8%. The lethal dose to Tadpoles in the concentration of domestic sewage for up to 80%, the semi-lethal dose is 60%, 50% of sewage affected obviously, and even teratogenic, 50% of sewage is the most obvious of body length and tail length.

  15. A comparison of human chorionic gonadotropin and luteinizing hormone releasing hormone on the induction of spermiation and amplexus in the American toad (Anaxyrus americanus

    Directory of Open Access Journals (Sweden)

    Kouba Andrew J

    2012-08-01

    Full Text Available Abstract Background Captive breeding programs for endangered amphibian species often utilize exogenous hormones for species that are difficult to breed. The purpose of our study was to compare the efficacy of two different hormones at various concentrations on sperm production, quantity and quality over time in order to optimize assisted breeding. Methods Male American toads (Anaxyrus americanus were divided into three separate treatment groups, with animals in each group rotated through different concentrations of luteinizing hormone releasing hormone analog (LHRH; 0.1, 1.0, 4.0 and 32 micrograms/toad, human chorionic gonadotropin (hCG; 50, 100, 200, and 300 IU, or the control over 24 hours. We evaluated the number of males that respond by producing spermic urine, the sperm concentration, percent motility, and quality of forward progression. We also evaluated the effects of hCG and LHRH on reproductive behavior as assessed by amplexus. Data were analyzed using the Generalized Estimating Equations incorporating repeated measures over time and including the main effects of treatment and time, and the treatment by time interaction. Results The hormone hCG was significantly more effective at stimulating spermiation in male Anaxyrus americanus than LHRH and showed a dose-dependent response in the number of animals producing sperm. At the most effective hCG dose (300 IU, 100% of the male toads produced sperm, compared to only 35% for the best LHRH dose tested (4.0 micrograms. In addition to having a greater number of responders (P  Conclusion There is a clear dichotomy between the two hormones’ physiological responses on gamete production and stimulation of amplexus. Understanding how these two hormones influence physiology and reproductive behaviors in amphibians will have direct bearing on establishing similar breeding protocols for endangered species.

  16. Effects of landscape composition and wetland fragmentation on frog and toad abundance and species richness in Iowa and Wisconsin, USA [abstract

    Science.gov (United States)

    Knutson, M.G.; Sauer, J.R.; Olsen, D.A.; Mossman, M.J.; Hemesath, L.M.; Lannoo, M.J.

    1998-01-01

    We examined the relationships between anuran diversity and landscape features in the Upper Midwestern United States. Anuran relative abundance and species richness were measured using data collected by Wisconsin and Iowa state calling surveys conducted from 1990-1995. Landscape features surrounding survey points were determined using National Wetland Inventory and Wisconsin Wetland Inventory maps. We tested several hypotheses suggested by the literature. We hypothesized that the relative abundance and species richness of anurans that breed in ephemeral wetlands is positively correlated with the surrounding area of temporary wetlands and emergent wetlands. We hypothesized that the relative abundance and species richness of anurans is positively correlated with patch diversity and wetland edges, in the absence of local fragmentation effects. We hypothesized that the relative abundance and species richness of anurans is positively associated with forests but negatively associated with agriculture and urban areas. Our results show that the interspersion of different wetland types and the concomitant increase in wetland edge habitats were generally positive for frogs and toads and anuran abundance and diversity were generally higher in association with forests, especially forested wetlands. The presence of agriculture did not always depress frog and toad populations or diversity; some species were associated with agricultural landscapes. The two states differed in how anurans were associated with landscape features like lakes and permanent wetlands. We found that frog and toad relative abundance and diversity were lower when urban areas were present. Managers can use models like ours, generated from landscape analyses, along with range maps and population trend analyses to get a comprehensive picture of the health of individual species and groups of species. Our models could be applied to the landscape as a whole, and used to predict species relative abundance and

  17. Ontogeny of corticotropin-releasing factor effects on locomotion and foraging in the Western spadefoot toad (Spea hammondii).

    Science.gov (United States)

    Crespi, Erica J; Denver, Robert J

    2004-11-01

    We investigated the effects of corticotropin-releasing factor (CRF) and corticosterone (CORT) on foraging and locomotion in Western spadefoot toad (Spea hammondii) tadpoles and juveniles to assess the behavioral functions of these hormones throughout development. We administered intracerebroventricular injections of ovine CRF or CRF receptor antagonist alphahelical CRF((9-41)) to tadpoles and juveniles, and observed behavior within 1.5 h after injection. In both premetamorphic (Gosner stage 33) and prometamorphic (Gosner stages 35-37) tadpoles, CRF injections increased locomotion and decreased foraging. Injections of alphahelical CRF((9-41)) reduced locomotion but did not affect foraging in premetamorphic tadpoles, but dramatically increased foraging in prometamorphic tadpoles compared to both placebo and uninjected controls. Similarly, alphahelical CRF((9-41)) injections stimulated food intake and prey-catching behavior in juveniles. These results suggest that in later-staged amphibians, endogenous CRF secretion modulates feeding by exerting a suppressive effect on appetite. By contrast to the inhibitory effect of CRF, 3-h exposure to CORT (500 nM added to the aquarium water) stimulated foraging in prometamorphic tadpoles. These tadpoles also exhibited a CORT-mediated increase in foraging 6 h after CRF injection, which was associated with elevated whole-body CORT content and blocked by glucocorticoid receptor (GR) antagonist (RU486) injections. Thus, exogenous CRF influences locomotion and foraging in both pre- and prometamorphic tadpoles, but endogenous CRF secretion in relatively unstressed animals does not affect foraging until prometamorphic stages. Furthermore, the opposing actions of CRF and CORT on foraging suggest that they are important regulators of energy balance and food intake in amphibians throughout development.

  18. Climate change and the distribution of neotropical red-bellied toads (Melanophryniscus, Anura, Amphibia): how to prioritize species and populations?

    Science.gov (United States)

    Zank, Caroline; Becker, Fernando Gertum; Abadie, Michelle; Baldo, Diego; Maneyro, Raúl; Borges-Martins, Márcio

    2014-01-01

    We used species distribution modeling to investigate the potential effects of climate change on 24 species of Neotropical anurans of the genus Melanophryniscus. These toads are small, have limited mobility, and a high percentage are endangered or present restricted geographical distributions. We looked at the changes in the size of suitable climatic regions and in the numbers of known occurrence sites within the distribution limits of all species. We used the MaxEnt algorithm to project current and future suitable climatic areas (a consensus of IPCC scenarios A2a and B2a for 2020 and 2080) for each species. 40% of the species may lose over 50% of their potential distribution area by 2080, whereas 28% of species may lose less than 10%. Four species had over 40% of the currently known occurrence sites outside the predicted 2080 areas. The effect of climate change (decrease in climatic suitable areas) did not differ according to the present distribution area, major habitat type or phylogenetic group of the studied species. We used the estimated decrease in specific suitable climatic range to set a conservation priority rank for Melanophryniscus species. Four species were set to high conservation priority: M. montevidensis, (100% of its original suitable range and all known occurrence points potentially lost by 2080), M. sp.2, M. cambaraensis, and M. tumifrons. Three species (M. spectabilis, M. stelzneri, and M. sp.3) were set between high to intermediate priority (more than 60% decrease in area predicted by 2080); nine species were ranked as intermediate priority, while eight species were ranked as low conservation priority. We suggest that monitoring and conservation actions should be focused primarily on those species and populations that are likely to lose the largest area of suitable climate and the largest number of known populations in the short-term.

  19. Roles of external and cellular Cl- ions on the activation of an apical electrodiffusional Cl- pathway in toad skin.

    Science.gov (United States)

    Procopio, J; Lacaz-Vieira, F

    1990-07-01

    This study is concerned with the short-circuit current, Isc, responses of the Cl(-)-transporting cells of toad skin submitted to sudden changes of the external Cl- concentration, [Cl]o. Sudden changes of [Cl]o, carried out under apical membrane depolarization, allowed comparison of the roles of [Cl]o and [Cl]cell on the activation of the apical Cl- pathways. Equilibration of short-circuited skins symmetrically in K-Ringer's solutions of different Cl- concentrations permitted adjustment of [Cl]cell to different levels. For a given Cl- concentration (in the range of 11.7 to 117 mM) on both sides of a depolarized apical membrane, this structure exhibits a high Cl- permeability, P(Cl)apical. On the other hand, for the same range of [Cl]cell but with [Cl]o = 0, P(Cl)apical is reduced to negligible values. These observations indicate that when the apical membrane is depolarized P(Cl)apical is modulated by [Cl]o; in the absence of external Cl- ions, intracellular Cl- is not sufficient to activate P(Cl)apical. Computer simulation shows that the fast Cl- currents induced across the apical membrane by sudden shifts of [Cl]o from a control equilibrium value strictly follow the laws of electrodiffusion. For each experimental group, the computer-generated Isc versus [( Cl]cell - [Cl]o) curve which best fits the experimental data can only be obtained by a unique pair of P(Cl)apical and Rb (resistance of the basolateral membrane), thus allowing the calculation of these parameters. The electrodiffusional behavior of the net Cl- flux across the apical membrane supports the channel nature of the apical Cl- pathways in the Cl(-)-transporting cells. Cl- ions contribute significantly to the overall conductance of the basolateral membrane even in the presence of a high K concentration in the internal solution. PMID:1698229

  20. Mixed population genomics support for the central marginal hypothesis across the invasive range of the cane toad (Rhinella marina) in Australia.

    Science.gov (United States)

    Trumbo, Daryl R; Epstein, Brendan; Hohenlohe, Paul A; Alford, Ross A; Schwarzkopf, Lin; Storfer, Andrew

    2016-09-01

    Understanding factors that cause species' geographic range limits is a major focus in ecology and evolution. The central marginal hypothesis (CMH) predicts that species cannot adapt to conditions beyond current geographic range edges because genetic diversity decreases from core to edge due to smaller, more isolated edge populations. We employed a population genomics framework using 24 235-33 112 SNP loci to test major predictions of the CMH in the ongoing invasion of the cane toad (Rhinella marina) in Australia. Cane toad tissue samples were collected along broad-scale, core-to-edge transects across their invasive range. Geographic and ecological core areas were identified using GIS and habitat suitability indices from ecological niche modelling. Bayesian clustering analyses revealed three genetic clusters, in the northwest invasion-front region, northeast precipitation-limited region and southeast cold temperature-limited region. Core-to-edge patterns of genetic diversity and differentiation were consistent with the CMH in the southeast, but were not supported in the northeast and showed mixed support in the northwest. Results suggest cold temperatures are a likely contributor to southeastern range limits, consistent with CMH predictions. In the northeast and northwest, ecological processes consisting of a steep physiological barrier and ongoing invasion dynamics, respectively, are more likely explanations for population genomic patterns than the CMH. PMID:27393238

  1. Regulation of cyclic GMP metabolism in toad photoreceptors. Definition of the metabolic events subserving photoexcited and attenuated states.

    Science.gov (United States)

    Dawis, S M; Graeff, R M; Heyman, R A; Walseth, T F; Goldberg, N D

    1988-06-25

    Photoreceptor metabolism of cGMP and its regulation were characterized in isolated toad retinas by determining the intensity and time dependence of light-induced changes in the following metabolic parameters: cGMP hydrolytic flux determined by the rate of 18O incorporation from 18O-water into retinal guanine nucleotide alpha-phosphoryls; changes in the total (protein-bound and unbound) concentrations of the guanine nucleotide metabolic intermediates; and changes in the concentration of metabolic (unbound) GDP calculated from the fraction of the alpha-GDP that undergoes labeling with 18O. The latter is interpreted to reflect the state of the equilibrium between GDP- and GTP-complexed forms of G-protein. With narrow band 500 nm light that preferentially stimulates red rod photoreceptors, a range of intensities covering approximately 5 log units produced increases of over 10-fold in cGMP metabolic flux. However, the characteristics of the cGMP metabolic response over the first 2.5 log units of intensity are readily distinguishable from those at higher intensities which exhibit progressive attenuation by an intensity- and time-dependent process. Over the range of low intensities (0.6-3 log photons.micron-2.s-1) the metabolic response is characterized by 1) increases in cGMP hydrolytic flux of up to 8-fold as a logarithmic function of intensity of photic stimulation that are sustained for at least 200 s; 2) small increases or no change in the concentration of total cGMP; 3) large increases of up to 10-fold in the concentration of metabolically active GDP as a linear function of intensity with no significant change in the tissue concentrations of total GDP or GTP; and 4) amplification of the photosignal by the metabolism of approximately 10,000 molecules of cGMP per photoisomerization with the major site of amplification at the level of the interaction of bleached rhodopsin with G-protein.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. 长波紫外线照射对花背蟾蜍肾脏结构损伤%Impacts of long-wave ultraviolet radiation on kidney structure of Bufo Raddei

    Institute of Scientific and Technical Information of China (English)

    屈婷婷; 李丕鹏; 聂颖; 陆宇燕

    2012-01-01

    为研究长波紫外线对花背蟾蜍(Bufo raddei)肾脏的损伤,用波长为365 nm的长波紫外线(UVA)以352 μW·cm-2的辐射量对花背蟾蜍亚成体进行150、300和450 min的连续照射,分别在照射后立即、3、6、9、12和15 d取材,常规石蜡切片.结果表明:UVA照射后,3组不同照射时间的花背蟾蜍肾脏整体结构基本完整,但均出现肾小管管壁破裂,管径显著缩小,肾小囊消失,而300 min照射组的损伤则极为明显,其后依次为450 min照射组与150 min照射组,300与450 min照射组的肾小体塌陷程度较150 min照射组更为严重;经15 d的恢复,虽出现明显好转,但大多指标仍与对照组间存在极显著性差异;UVA对花背蟾蜍肾脏有着不可忽视的损伤,虽然具有一定的自我修复的能力,但在野外,紫外辐射的增强和植被的减少可导致两栖类遭受过度的紫外辐射,进而引起两栖类种群的衰减.%In order to study the damage of long-wave ultraviolet (UVA) on Bufo raddei kidney, three groups of Bufo raddeis juveniles were irradiated continuously by 365 nm UVA with a dosage of 352 μW · cm-2 for 150, 300, and 450 min, respectively, and the kidney after the irradiation was dissected immediately and 3, 6, 9, 12, and 15 days later, with its histological changes observed by general histological method. After the UVA radiation, the kidney structure was basically in integrity, except the fracture and visible constriction of renal tubule and the disappearance of renal capsule, which were most obvious in the 300 min group, followed by in 450 min group and in 150 min group. The damage to Malpigkian bodies was more serious in 300 and 450 min groups than in 150 min group. After 15 days recovery, though the damage was somewhat mitigated , most of the histological indices of the three experimental groups were significantly different from the control group. This study showed that the damage of UVA to B. raddei kidney could not be ignored in spite of

  3. Peptide IC-20, encoded by skin kininogen-1 of the European yellow-bellied toad, Bombina variegata, antagonizes bradykinin-induced arterial smooth muscle relaxation

    Directory of Open Access Journals (Sweden)

    Mu Yang

    2011-01-01

    Full Text Available Objectives: The objectives were to determine if the skin secretion of the European yellow-bellied toad (Bombina variegata, in common with other related species, contains a bradykinin inhibitor peptide and to isolate and structurally characterize this peptide. Materials and Methods: Lyophilized skin secretion obtained from this toad was subjected to reverse phase HPLC fractionation with subsequent bioassay of fractions for antagonism of the bradykinin activity using an isolated rat tail artery smooth muscle preparation. Subsequently, the primary structure of the peptide was established by a combination of microsequencing, mass spectroscopy, and molecular cloning, following which a synthetic replicate was chemically synthesised for bioassay. Results: A single peptide of molecular mass 2300.92 Da was resolved in HPLC fractions of skin secretion and its primary structure determined as IYNAIWP-KH-NK-KPGLL-. Database interrogation with this sequence indicated that this peptide was encoded by skin kininogen-1 previously cloned from B. variegata. The blank cycles were occupied by cysteinyl (C residues and the peptide was located toward the C-terminus of the skin kininogen, and flanked N-terminally by a classical -KR- propeptide convertase processing site. The peptide was named IC-20 in accordance (I = N-terminal isoleucine, C = C-terminal cysteine, 20 = number of residues. Like the natural peptide, its synthetic replicate displayed an antagonism of bradykinin-induced arterial smooth muscle relaxation. Conclusion: IC-20 represents a novel bradykinin antagonizing peptide from amphibian skin secretions and is the third such peptide found to be co-encoded with bradykinins within skin kininogens.

  4. The influences of the herbicide glyphosate on nerve impulse generation and conduction of Bufo gargarizans%草甘膦胁迫对中华大蟾蜍(Bufo gargarizans)神经冲动产生和传导的影响

    Institute of Scientific and Technical Information of China (English)

    肖永红; 龙婉婉; 罗斯成; 尹彩萍; 龙进

    2007-01-01

    应用电生理方法研究了除草剂草甘膦对中华大蟾蜍 (Bufo gargarizans Cantor) 坐骨神经干冲动产生和传导的影响.用不同浓度的草甘膦溶液对中华大蟾蜍进行胁迫处理,草甘膦有效成分经由皮肤进入蟾蜍体内而作用于神经系统,利用生物信号采集处理系统测定草甘膦胁迫下中华大蟾蜍离体坐骨神经干的应激反应时间、动作电位幅度和冲动传导速度,结果表明:随着草甘膦溶液浓度的升高,中华大蟾蜍坐骨神经干接受刺激后产生冲动所需的时间逐渐延长,动作电位峰值降低,神经冲动传导速度亦逐渐减慢.草甘膦施用后,中华大蟾蜍7d内的平均应激反应时间与草甘膦浓度呈正相关,而动作电位幅度及传导速度均与草甘膦浓度呈负相关.草甘膦溶液浓度达到推荐农田使用浓度1.64~2.87ml/L时,各处理组蟾蜍的应激反应时间、动作电位幅度和冲动传导速度均与对照组差异极显著(P<0.01).同时,随着试验处理时间的延长,中华大蟾蜍神经干对刺激的反应变得更为迟钝,神经冲动的传导速度也进一步减慢.回归分析可知,中华大蟾蜍坐骨神经干的应激反应时间与草甘膦施用后天数呈正相关,而神经传导速度与药后天数呈负相关.由此可以说明,草甘膦胁迫条件下,中华大蟾蜍神经细胞对刺激反应的灵敏性降低,动作电位的产生及传导受到一定程度的抑制和阻碍.

  5. Amfibieundersøkelser i Mykland, Aust-Agder Hvor finnes de og hvorfor?

    OpenAIRE

    Andersen, Eivind Ekholt

    2013-01-01

    In many parts of the world there are reports of significant declines in amphibian populations. A number of reasons for the declines exist. Water acidification caused by acid rain, is a likely cause of decline of amphibians in acid sensitive areas, as in parts of southern Norway. Field surveys of toad (Bufo bufo) and smooth newt (Triturus vulgaris), was combined with water chemistry surveys and registration of fish species in 15 sites, mainly in Mykland, Aust- Agder, in the peri...

  6. 蟾蜍壶菌病病原遗传分化研究%Genetic Differentiation of the Pathogen of Batrachochytrium dendrobatidis in Toads

    Institute of Scientific and Technical Information of China (English)

    曾朝辉; 白世卓; 朱蕴绮; 王晓龙

    2011-01-01

    壶菌病为近年发现的两栖类动物重要传染病,对野生和养殖种群危害极大,为确定药用经济动物蟾蜍历史上壶菌病感染情况,提高养殖蟾蜍疾病防治水平,选取某博物馆馆藏采集于四川的蟾蜍标本32只,利用Taqman—MGB荧光探针定量PCR技术进行壶菌检测,并对定量PCR产物克隆、测序,通过序列比对和系统发育分析判定其来源。最终得到定量PCR标准曲线:Y=-3.0X+32.39;相关系数R0=0.9996;检测结果为阳性样本12只,检出率37.5%。同时系统发育分析表明,我国的壶菌存在一定程度的分化,一类与北美洲、南美洲、欧洲菌株呈现高度的亲缘关系;另一类则表现出与世界其他地区分布的壶菌有明显的不同,显示其独特性。这提示我国蟾蜍壶菌病的防制应更具针对性,不可盲目照搬国外经验。%The chytridiomycosis is a significant emerging disease of amphibians in recent years which seriuosly does harm to the wild and breeding population. To ascertain the condition of the Batrachochytrium dendrobatidis infection history in the population of toad, the medicinal economic animal, and enhance the prevention for this disease, 32 toad specimen collected from Sichwan keeping in a museum were assayed by Taqman-MGB fluorescence probe quantitative polymerase chain reaction to detect Batrachochytrium dendrobatidis. Besides, the products of QPCR were cloned and sequenced to identify the origin of the pathogen by sequence alignment and phylogenetie analysis. Finally we got the standard curve: Y = - 3.0X + 32.39 and the related coefficient: R2 = 0.999 6. Total 12 positive samples reported the detec- tion rate as 37.5 %. Meanwhile the phylogenetic analysis indicated that a certain extent differentiation of the chytrid fungi in our country exists. One kind of the tested strain showed highly genetic relationship with the strains from the North America, South America

  7. Hybridization and massive mtDNA unidirectional introgression between the closely related Neotropical toads Rhinella marina and R. schneideri inferred from mtDNA and nuclear markers

    Directory of Open Access Journals (Sweden)

    Schneider Horacio

    2011-09-01

    Full Text Available Abstract Background The classical perspective that interspecific hybridization in animals is rare has been changing due to a growing list of empirical examples showing the occurrence of gene flow between closely related species. Using sequence data from cyt b mitochondrial gene and three intron nuclear genes (RPL9, c-myc, and RPL3 we investigated patterns of nucleotide polymorphism and divergence between two closely related toad species R. marina and R. schneideri. By comparing levels of differentiation at nuclear and mtDNA levels we were able to describe patterns of introgression and infer the history of hybridization between these species. Results All nuclear loci are essentially concordant in revealing two well differentiated groups of haplotypes, corresponding to the morphologically-defined species R. marina and R. schneideri. Mitochondrial DNA analysis also revealed two well-differentiated groups of haplotypes but, in stark contrast with the nuclear genealogies, all R. schneideri sequences are clustered with sequences of R. marina from the right Amazon bank (RAB, while R. marina sequences from the left Amazon bank (LAB are monophyletic. An Isolation-with-Migration (IM analysis using nuclear data showed that R. marina and R. schneideri diverged at ≈ 1.69 Myr (early Pleistocene, while R. marina populations from LAB and RAB diverged at ≈ 0.33 Myr (middle Pleistocene. This time of divergence is not consistent with the split between LAB and RAB populations obtained with mtDNA data (≈ 1.59 Myr, which is notably similar to the estimate obtained with nuclear genes between R. marina and R. schneideri. Coalescent simulations of mtDNA phylogeny under the speciation history inferred from nuclear genes rejected the hypothesis of incomplete lineage sorting to explain the conflicting signal between mtDNA and nuclear-based phylogenies. Conclusions The cytonuclear discordance seems to reflect the occurrence of interspecific hybridization between these

  8. Influence of geology and human activity on the genetic structure and demography of the Oriental fire-bellied toad (Bombina orientalis).

    Science.gov (United States)

    Fong, Jonathan J; Li, Pi-Peng; Yang, Bao-Tian; Zhou, Zheng-Yan; Leaché, Adam D; Min, Mi-Sook; Waldman, Bruce

    2016-04-01

    The Oriental fire-bellied toad (Bombina orientalis) is a commonly used study organism, but knowledge of its evolutionary history is incomplete. We analyze sequence data from four genetic markers (mtDNA genes encoding cytochrome c oxidase subunit I, cytochrome b, and 12S-16S rRNA; nuDNA gene encoding recombination activating gene 2) from 188 individuals across its range in Northeast Asia to elucidate phylogeographic patterns and to identify the historic events that shaped its evolutionary history. Although morphologically similar across its range, B. orientalis exhibits phylogeographic structure, which we infer was shaped by geologic, climatic, and anthropogenic events. Phylogenetic and divergence-dating analyses recover four genetically distinct groups of B. orientalis: Lineage 1-Shandong Province and Beijing (China); Lineage 2-Bukhan Mountain (Korea); Lineage 3-Russia, Northeast China, and northern South Korea; and Lineage 4-South Korea. Lineage 2 was previously unknown. Additionally, we discover an area of secondary contact on the Korean Peninsula, and infer a single dispersal event as the origin of the insular Jeju population. Skyline plots estimate different population histories for the four lineages: Lineages 1 and 2 experienced population decreases, Lineage 3 remained stable, while Lineage 4 experienced a sharp increase during the Holocene. The timing of the population expansion of Lineage 4 coincides with the advent of rice cultivation, which may have facilitated the increase in population size by providing additional breeding habitat.

  9. Chemical skin defence in the Eastern fire-bellied toad Bombina orientalis: an ultrastructural approach to the mechanism of poison gland rehabilitation after discharge

    Directory of Open Access Journals (Sweden)

    Sara Quagliata

    2008-12-01

    Full Text Available Type I serous glands in the skin of the Eastern yellow-bellied toad Bombina orientalis released their product massively after 10-3 M nor-adrenalin (NA stimulation, mimicking orthosympathetic control on poison emission in chemical skin defence. Features of cutaneous glands involved in this bulk discharge were observed under light and electron microscopes. Furthermore, restoration of depleted glands was followed after 1, 2 and 3 weeks, and compared with serous biosynthesis during larval gland development. Bulk discharge was caused by contraction of myoepithelial cells (mecs encircling the secretory units. Mec compression dramatically affected the secretory unit, but parts of this syncytial cytoplasm were saved from degeneration and cooperated in gland renewal with stem cells from the gland neck. These adenoblasts underwent proliferation and secretory cytodifferentiation, until merging with the syncytium. Cytoplasm that had resumed secretory activity showed the features typical of larval gland development: the endoplasmic reticulum (rer cisterns were aligned in close parallel arrangement and Golgi stacks released minute type I granules. Secretory rehabilitation led to increasing amounts of granule content. In the meantime, rough cisterns decreased in number and assumed the less ordered pattern described in control specimens. Data collected in the present study revealed that chemical skin defence in anurans is a multi-factorial mechanism involving specific activities: mechanical from mecs, biosynthetic from secretory syncytium and proliferative from intercalated stem cells.

  10. Structural and functional analogs of the novel mammalian neuropeptide, neuromedin S (NmS), in the dermal venoms of Eurasian bombinid toads.

    Science.gov (United States)

    Chen, Tianbao; Zhou, Mei; Walker, Brian; Harriot, Pat; Mori, Kenji; Miyazato, Mikiya; Kangawa, Kenji; Shaw, Chris

    2006-06-23

    We report the isolation and structural characterization of two neuromedin S (NmS) analogs, (NmS-17 and NmS-33), from the dermal venoms of Eurasian bombinid toads. NmS is a novel neuromedin U (NmU)-related peptide with potent anorexigenic and circadian rhythm-modulating properties recently discovered in mammals. Cloning of NmS precursor-encoding cDNAs from skin venom-derived libraries revealed the presence of a high degree of transcript splice variation comparable to that found previously for NmU in both amphibian skin and mammalian brain. Synthetic replicates of both amphibian NmS peptides evoked robust and dose-dependent transient increases in intracellular calcium ion concentrations in CHO cells that had been stably transfected with either FM-3/GPR66 or FM-4/TGR-1 human NmU receptors. The potency and efficacy of these amphibian skin peptides at such receptors were comparable to those observed with human NmS and rat NmS. These data show that NmS and NmU genes had already diverged at the level of the Amphibia and that differential splicing of their transcribed mRNAs has been highly conserved throughout tetrapod vertebrate evolution indicative of fundamental biological function. NmS is additionally a novel neuropeptide homolog that can be added to the biologically active peptide arsenal of amphibian venom/defensive skin secretions.

  11. Influence of geology and human activity on the genetic structure and demography of the Oriental fire-bellied toad (Bombina orientalis).

    Science.gov (United States)

    Fong, Jonathan J; Li, Pi-Peng; Yang, Bao-Tian; Zhou, Zheng-Yan; Leaché, Adam D; Min, Mi-Sook; Waldman, Bruce

    2016-04-01

    The Oriental fire-bellied toad (Bombina orientalis) is a commonly used study organism, but knowledge of its evolutionary history is incomplete. We analyze sequence data from four genetic markers (mtDNA genes encoding cytochrome c oxidase subunit I, cytochrome b, and 12S-16S rRNA; nuDNA gene encoding recombination activating gene 2) from 188 individuals across its range in Northeast Asia to elucidate phylogeographic patterns and to identify the historic events that shaped its evolutionary history. Although morphologically similar across its range, B. orientalis exhibits phylogeographic structure, which we infer was shaped by geologic, climatic, and anthropogenic events. Phylogenetic and divergence-dating analyses recover four genetically distinct groups of B. orientalis: Lineage 1-Shandong Province and Beijing (China); Lineage 2-Bukhan Mountain (Korea); Lineage 3-Russia, Northeast China, and northern South Korea; and Lineage 4-South Korea. Lineage 2 was previously unknown. Additionally, we discover an area of secondary contact on the Korean Peninsula, and infer a single dispersal event as the origin of the insular Jeju population. Skyline plots estimate different population histories for the four lineages: Lineages 1 and 2 experienced population decreases, Lineage 3 remained stable, while Lineage 4 experienced a sharp increase during the Holocene. The timing of the population expansion of Lineage 4 coincides with the advent of rice cultivation, which may have facilitated the increase in population size by providing additional breeding habitat. PMID:26748269

  12. Records of Sandflies (Diptera: Psychodidae: Phlebotominae feeding on Amphibia, with A new record from the Kruger National Park

    Directory of Open Access Journals (Sweden)

    H. H Braack

    1981-01-01

    Full Text Available An early record of a sandfly feeding on an amphibian is that of Hewlett (1913, Indian J. med. Res. 1: 34-38 who wrote "I have twice seen a sandfly apparently biting the head of the common toad Bufo melanostictus".

  13. The Feeding Habits of Toad-headed Lizard (Phrynocephalus frontalis) in Autumn%草原沙蜥秋季食性分析

    Institute of Scientific and Technical Information of China (English)

    赵雪; 毕俊怀; 刘睿; 何志超; 陈绍勇

    2013-01-01

    We studied the food habits of Toad-headed Lizard (Phrynocephalus frontalis) collected in the Erdos region of Inner Mongolia using stomach dissection.The results show that Toad-headed Lizard prefers insects which account for 95.8% of all the food items in the period from August to September.No significant difference in food items was found between male and female although the index of food diversity (IFD) and the breadth of trophic niche (BTN) were greater in males than those in females.No any difference in food habits was found between adults and subadults or between subadults and juveniles,however,significant difference was detected between adults and juveniles.The percent similarity of food index was great between sexes and lower in different age group.The IFD and the BTN in different ages was the greatest in adults and the lowest in juveniles.The general beneficial coefficient,the beneficial coefficient in different gender and ages were VTotal =22.44%,VFemale =12.76%,VMale =9.83%.The P.frontalis is a species beneficial to the desert steppe.%利用剖胃法对采自内蒙古自治区鄂尔多斯库布齐沙漠的草原沙蜥(Phrynocephalus frontalis)进行食性分析研究.结果表明,该地区的草原沙蜥在8~9月间,以昆虫类动物为主要食物,占全部食物的95.8%.不同性别草原沙蜥取食的食物种类差异不显著,雌雄个体的食物百分率相似性指数及营养生态位重叠值均较大,雄性的食物多样性指数(IFD)及营养生态位宽度(BTN)均大于雌性.成体和亚成体之间以及亚成体和幼体之间食物种类存在差异但不显著,而成体和幼体间的食物种类差异极显著,不同年龄草原沙蜥的食物百分率相似性指数较小,IFD值与BTN值均是成体最大,幼体最小.总有益系数、不同性别的有益系数分别为V总=22.44%,V雌=12.76%,V雄=9.83%,草原沙蜥是对荒漠化草原有益的类群.

  14. Synergy between glyphosate- and cypermethrin-based pesticides during acute exposures in tadpoles of the common South American toad Rhinella arenarum.

    Science.gov (United States)

    Brodeur, Julie Céline; Poliserpi, María Belén; D'Andrea, María Florencia; Sánchez, Marisol

    2014-10-01

    The herbicide glyphosate and the insecticide cypermethrin are key pesticides of modern management in soy and corn cultures. Although these pesticides are likely to co-occur in ephemeral ponds or aquatic systems supporting amphibian wildlife, the toxicological interactions prevailing in mixtures of these two pesticides have been little studied. The current study evaluated the toxicity of equitoxic and non-equitoxic binary mixtures of glyphosate- and cypermethrin-based pesticides to tadpoles of the common South American toad, Rhinella arenarum. Two different combinations of commercial products were tested: glyphosate Glifosato Atanor®+cypermethrin Xiper® and glyphosate Glifoglex®+cypermethrin Glextrin®. When tested individually, the formulations presented the following 96 h-LC50s: Glifosato Atanor® 19.4 mg ae L(-1) and Glifoglex 72.8 mg ae L(-1), Xiper® 6.8 mg L(-1) and Glextrin® 30.2 mg L(-1). Equitoxic and non-equitoxic mixtures were significantly synergic in both combinations of commercial products tested. The magnitude of the synergy (factor by which toxicity differed from concentration addition) was constant at around twofold for all tested proportions of the glyphosate Glifoglex®+cypermethrin Glextrin® mixture; whereas the magnitude of the synergy varied between 4 and 9 times in the glyphosate Glifosato Atanor®+cypermethrin Xiper® mixture. These results call for more research to be promptly undertaken in order to understand the mechanisms behind the synergy observed and to identify and quantify the extent of its environmental impacts. PMID:25048890

  15. Binding of adrenergic ligands to liver plasma membrane preparations from the axolotl, Ambystoma mexicanum; the toad, Xenopus laevis; and the Australian lungfish, Neoceratodus forsteri.

    Science.gov (United States)

    Janssens, P A; Grigg, J A

    1988-09-01

    The beta-adrenergic ligand iodocyanopindolol (ICP) bound specifically to hepatic plasma membrane preparations from the axolotl, Ambystoma mexicanum (Bmax, 40 fmol/mg protein (P) at free concentration above 140 pM; KD, 42 pM); the toad, Xenopus laevis (Bmax, 200 fmol/mg P at 1 nM; KD, 300 pM); and the Australian lungfish, Neoceratodus forsteri (Bmax, 100 fmol/mg P at 5 nM). For the lungfish, the Scatchard plot was curved showing two classes of binding site with KD's of 20 and 500 pM. Neither the alpha 1-adrenergic ligand prazosin nor the alpha 2-adrenergic ligand yohimbine bound specifically to hepatic membrane preparations from any of the three species. Several adrenergic ligands displaced ICP from hepatic membrane preparations of all three species with KD's of Axolotl--propranolol, 50 nM; isoprenaline, 600 nM; adrenaline, 10 microM; phenylephrine, 20 microM; noradrenaline, 40 microM; and phentolamine, greater than 100 microM; X. laevis--propranolol, 30 nM; isoprenaline, 100 microM; adrenaline, 200 microM; noradrenaline, 300 microM; phenylephrine, 1 mM; and phentolamine, greater than 1 mM; N. forsteri,--propranolol, 25 nM; isoprenaline, 1 microM; adrenaline, 20 microM; phenylephrine, 35 microM; noradrenaline, 600 microM; and phentolamine, 400 microM. These findings suggest that alpha-adrenergic receptors are not present in hepatic plasma membrane preparations from these three species and that the hepatic actions of catecholamines are mediated via beta-adrenergic receptors. The order of binding of the beta-adrenergic ligands suggests that the receptors are of the beta 2 type.

  16. Effects of landscape composition and wetland fragmentation on frog and toad abundance and species richness in Iowa and Wisconsin, U.S.A

    Science.gov (United States)

    Knutson, Melinda G.; Sauer, John R.; Olsen, Douglas A.; Mossman, Michael J.; Hemesath, Lisa M.; Lannoo, Michael J.

    1999-01-01

    Management of amphibian populations to reverse recent declines will require defining high-quality habitat for individual species or groups of species, followed by efforts to retain or restore these habitats on the landscape. We examined landscape-level habitat relationships for frogs and toads by measuring associations between relative abundance and species richness based on survey data derived from anuran calls and features of land-cover maps for Iowa and Wisconsin. The most consistent result across all anuran guilds was a negative association with the presence of urban land. Upland and wetland forests and emergent wetlands tended to be positively associated with anurans. Landscape metrics that represent edges and patch diversity also had generally positive associations, indicating that anurans benefit from a complex of habitats that include wetlands. In Iowa the most significant associations with relative abundance were the length of the edge between wetland and forest ( positive) and the presence of urban land (negative). In Wisconsin the two most significant associations with relative abundance were forest area and agricultural area ( both positive). Anurans had positive associations with agriculture in Wisconsin but not in Iowa. Remnant forest patches in agricultural landscapes may be providing refuges for some anuran species. Differences in anuran associations with deep water and permanent wetlands between the two states suggest opportunities for management action. Large-scale maps can contribute to predictive models of amphibian habitat use, but water quality and vegetation information collected from individual wetlands will likely be needed to strengthen those predictions. Landscape habitat analyses provide a framework for future experimental and intensive research on specific factors affecting the health of anurans.

  17. Blood lead levels, δ-ALAD inhibition, and hemoglobin content in blood of giant toad (Rhinella marina) to assess lead exposure in three areas surrounding an industrial complex in Coatzacoalcos, Veracruz, Mexico.

    Science.gov (United States)

    Ilizaliturri-Hernández, César Arturo; González-Mille, Donaji Josefina; Mejía-Saavedra, Jesús; Espinosa-Reyes, Guillermo; Torres-Dosal, Arturo; Pérez-Maldonado, Iván

    2013-02-01

    The Coatzacoalcos Region in Veracruz, Mexico houses one of the most important industrial complexes in Mexico and Latin America. Lead is an ubiquitous environmental pollutant which represents a great risk to human health and ecosystems. Amphibian populations have been recognized as biomonitors of changes in environmental conditions. The purpose of this research is to measure exposure to lead and evaluate hematological and biochemical effects in specimens of giant toads (Rhinella marina) taken from three areas surrounding an industrial complex in the Coatzacoalcos River downstream. Lead levels in toads' blood are between 10.8 and 70.6 μg/dL and are significantly higher in industrial sites. We have found a significant decrease in the delta-aminolevulinic acid dehydratase (δ-ALAD) activity in blood from 35.3 to 78 % for the urban-industrial and industrial sites, respectively. In addition, we have identified a strong inverse relationship between the δ-ALAD activity and the blood lead levels (r = -0.84, p marina can be considered a good biomonitor of the δ-ALAD activity inhibition and hematological alterations at low lead concentrations. PMID:22580791

  18. 中华蟾蜍蝌蚪变态过程中甲状腺的组织学变化%Changes of thyroid gland histological structures during the metamorphosis of Bufo gargarizans tadpole

    Institute of Scientific and Technical Information of China (English)

    刘静; 柴丽红; 吴民耀; 王宏元

    2012-01-01

    【目的】研究中华蟾蜍(Bufogargarizans)蝌蚪在不同发育阶段甲状腺的组织学变化。【方法】以处于变态高峰前后5期(28,33,38,42,46期)的中华蟾蜍蝌蚪为试验材料,用MoticBA300光学显微镜对各个发育时期蝌蚪的甲状腺进行组织学观察,测定蝌蚪的全长、体质量和肝质量等形态指标,并分析这些形态指标与甲状腺直径、滤泡平均直径及最大直径的线性相关性。【结果】在28期时,中华蟾蜍蝌蚪甲状腺出现但无分泌甲状腺激素的功能;33期时,甲状腺具备了分泌甲状腺激素的能力;此后甲状腺进一步发育,在蝌蚪前肢展开期甲状腺活性达到最强;至尾完全吸收期,甲状腺机能减弱。蝌蚪全长、体质量及肝质量与甲状腺直径及滤泡直径呈正线性相关。【结论】具有分泌机能的甲状腺出现的发育时期,与两栖动物变态类型相关;分泌高峰期出现的发育时期与幼体持续时间密切相关。中华蟾蜍蝌蚪的全长可以直观地反映其甲状腺的机能活性。%[Objective] The research was to study the changes of thyroid gland histological structures in tadpole of Bufo gargarizans during development. [Method] Tadpoles were taken from every five stages before and after metamorphosis(stage 28,stage 33,stage 38,stage 42 and stage 46),and histological struc- tures of thyroid glands in tadpoles were observed by Motic BA300 microscope. In addition, total length, body weight and liver weight of the tadpoles were measured. Then, the relationship was analyzed between total length, body weight, liver weight and thyroid gland, follicle diameter and follicle number. [Result] The thyroid gland was first present at the stage 28, but it lacked function. Thyroid gland possessed the abil- ity of secreting hormone at the stage 33. The activity of thyroid gland reached peak when forelimbs unfol- ded. The activity of thyroid gland declined

  19. Opus corpus: martirilogio bufo en tres cantos

    OpenAIRE

    Schrader París, Mariana

    2013-01-01

    “Opus Corpus” es un experimento que pasa necesariamente por el cuerpo –por mi cuerpo, en este caso- y que termina siendo catártico, psicomágico, sanador. El desamor es la prehistoria, la excusa, el material. La consecuencia son tres estados del cuerpo (uno detrás del otro, causalmente). Esta historia ordinaria está cantada (contada) desde los intestinos. Un primer cuerpo visceral empieza pidiendo a gritos ser volteado para que el desamor acumulado en sus entrañas se asolee u...

  20. Chloride channels in toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Rasmussen, B E

    1982-01-01

    - ions through this pathway. Experimental analysis of the gating kinetics is rendered difficult owing to a contamination of the gated currents by cellular ion redistribution currents. To obtain insight into the effects of accumulation-depletion currents on voltage clamp currents of epithelial membranes......, a mathematical model of the epithelium has been developed for computer analysis. By assuming that the apical membrane Cl- permeability is governed by a single gating variable (Hodgkin-Huxley kinetics), the model predicts fairly well steady-state current-voltage curves, the time course of current activations from...... a closed state, and the dependence of unidirectional fluxes on potential. Other predictions of the model do not agree with experimental findings, and it is suggested that the gating kinetics are governed by rate coefficients that also depend on the holding potential. Evidence is presented that Cl...

  1. 催产素对蟾蜍离体坐骨神经-腓肠肌收缩的影响%Effect of Oxytocin on the Isolated Toad Sciatic Nerve Gastrocnemius Contraction

    Institute of Scientific and Technical Information of China (English)

    刘晓霞; 付立波

    2015-01-01

    采用常规方法剥离制备神经-腓肠肌标本,分别用浸有0.5%、1%和1.5%催产素的纱布浸润标本,浸润5min后,测量蟾蜍坐骨神经-腓肠肌的阈强度(mv)、收缩幅度(g)以及收缩潜伏期(ms),与放入正常任氏液作比较。经0.5%的催产素浸润后,腓肠肌的阈强度无明显变化,收缩幅度增大,且潜伏期时间缩短;经1%的催产素浸润后,腓肠肌的阈强度减小,收缩幅度增大,潜伏期时间相应缩短;而经1.5%浓度的催产素浸润后,腓肠肌的阈强度、收缩幅度以及潜伏期均无明显变化。较低浓度催产素可以提高骨骼肌收缩的兴奋性,但受药物剂量的限制。超过一定范围,骨骼肌收缩不随催产素浓度变化或随浓度增加骨骼肌的收缩能力相应减弱。%Objective:To investigate the effect of oxytocin effect on isolated toad sciatic nerve gastrocnemius on -their contractile activi-ty.Methods:Method for preparing specimen gastrocnemius nerve -using conventional stripping process for the preparation of specimens, the gastrocnemius muscle of toad sciatic nerve -, respectively 0.5%, 1%and 1.5%leaching oxytocin gauze infiltration specimens, af-ter infiltration 5 minutes, measure the toad sciatic nerve of gastrocnemius threshold intensity ( mv) , contraction amplitude ( g) , and con-traction latency (MS).Results:After 0.5%of oxytocin after the invasion (P>0.05), the threshold intensity of gastrocnemius muscle had no obvious change, contraction amplitude increases, and shorten the latency time.After 1%of oxytocin after infiltration, reduce the threshold intensity of gastrocnemius muscle contraction amplitude increases, the contraction latencythe time gets shorter.The 1.5%con-centrations of oxytocin after the invasion (P>0.05), gastrocnemius muscle contraction amplitude and latency, threshold intensity had no obvious change.Conclusion:Contraction of the skeletal muscle affected by oxytocin

  2. Effects of an insecticide on amphibians in large-scale experimental ponds

    Science.gov (United States)

    Boone, M.D.; Semlitsch, R.D.; Fairchild, J.F.; Rothermel, B.B.

    2004-01-01

    We examined the effects of the insecticide carbaryl on larval amphibian communities in large-scale experimental ponds. Tadpoles of two anurans, Woodhouse's toad (Bufo woodhousii) and southern leopard Frog (Rana sphenocephala), were reared in ponds (800 m3 volume) to determine the effects of tadpole density and carbaryl exposure on mass at metamorphosis and on time and survival to metamorphosis. Exposure to carbaryl significantly affected toads at metamorphosis, but not leopard frogs. Carbaryl exposure nearly doubled toad survival compared to controls; this effect may be attributable to an indirect effect of earbaryl increasing algal food resources. The competitive environment (i.e., density) and carbaryl exposure significantly affected the trade-off between mass and time to metamorphosis for toads. Our study is the first to demonstrate that in pond communities where predation and competition may be strong, short-lived insecticides can significantly alter the community dynamics of amphibians.

  3. Use of stress-hormone levels and habitat selection to assess functional connectivity of a landscape for an amphibian.

    Science.gov (United States)

    Janin, Agnès; Léna, Jean-Paul; Deblois, Sandrine; Joly, Pierre

    2012-10-01

    The influence of landscape matrix on functional connectivity has been clearly established. Now methods to assess the effects of different land uses on species' movements are needed because current methods are often biased. The use of physiological parameters as indicators of the level of resistance to animal movement associated with different land uses (i.e., matrix resistance) could provide estimates of energetic costs and risks to animals migrating through the matrix. To assess whether corticosterone levels indicate matrix resistance, we conducted experiments on substrate choice and measured levels of corticosterone before and after exposure of toads (Bufo bufo) to 3 common substrates (ploughed soil, meadow, and forest litter). We expected matrix resistance and hormone levels to increase from forest litter (habitat of the toad) to meadows to ploughed soil. Adult toads had higher corticosterone levels on ploughed soil than on forest litter or meadow substrates. Hormone levels did not differ between forest litter and meadow. Toads avoided moving onto ploughed soil. Corticosterone levels in juvenile toads were not related to substrate type; however, hormone levels decreased as humidity increased. Juveniles, unlike adults, did not avoid moving over ploughed soil. The difference in responses between adult and juvenile toads may have been due to differences in experimental design (for juveniles, entire body used to measure corticosterone concentration; for adults, saliva alone); differences in the scale of sensory perception of the substrate (juveniles are much smaller than adults); or differences in cognitive processes between adult and juvenile toads. Adults probably had experience with different substrate types, whereas juveniles first emerging from the water probably did not. As a consequence, arable lands could act as ecological traps for juvenile toads. PMID:22891816

  4. 黄山地区人工养殖蟾蜍主要疾害及防治%Investigation and Prevention of Main Diseases of Artificial Breeding Toads in Huangshan Region

    Institute of Scientific and Technical Information of China (English)

    王德青; 唐鑫生

    2012-01-01

    2007年3月-2011年9月,对黄山地区人工养殖蟾蜍发生的主要疾害进行了调查,发现主要有腐皮病、红腿病、烂鳃病、胃肠炎、白内障、水霉病、气泡病等病害,车轮虫、舌杯虫和水蛭寄生虫害以及蛇、水虿、鸟等敌害。初步掌握了这些疾病的临床症状、病理变化、流行特点以及敌害种类,并对以上疾害提出了相应的防治措施。%The main diseases of artificial breeding toads in Huangshan region were investigated from March 2007 to September 2011. The investigation result shows there are decayed-skin, red-leg frog disease, decayed-cheek disease, enteritis, cataract, saprolegniasis, and bubble disease; three kinds of parasites (trichodinids, apisoma and sanguisuga) and some natural enemies (snake, dobson and bird). Further studies were made of the clinical symptoms, pathological changes, popular features, and predators of these diseases, and appropriate measures were put forward to prevent and treat them..

  5. 中华蟾蜍中脑视叶白介素1α、干扰素γ和肿瘤坏死因子α阳性细胞的分布%Distribution of IL-1α-, IFN-γ-and TNF-α-like immunoreactive cells in the optic lobe of Bufo gargariizans

    Institute of Scientific and Technical Information of China (English)

    杨乐乐; 刘再群

    2012-01-01

    Objective:To investigate the distribution of IL-lα-, IFN-y- and TNF-α-like immunoreactive cells in the optic lobe of Bufo gargariizans, and get much more knowledge of cytokines expressed in the brain in amphibians to aim at providing basic information of the study on cytokines acting on the central nervous system. Methods: The immunohistochemical SABC method and Nissl staining were used to observe the distribution of cells in the optic lobe under a light microscope, and statistic analysis was also used. Results: There were many IL-lcr and IFN-y- like immunoreactive cells in the whole optic lobe. They were large, middle or small sized cells, but most of them were middle and small sized cells. Their bodies were round and cone like in shape. Also, two sub-layers imunoreactive fibres were observed in the stratum zonale. TNF-α-like immunoreactive cells with middle or small size were only distributed in the dorsal tegmentum. Their bodies were round in shape. ' Conclusion: IL-1α and IFN-y-like immunoreactive cells were widely present in the whole optic lobe of Bufo gargariizans, but TNF-crlike immunoreactive cells were only observed in the dorsal tegmentum. do%目的:研究中华蟾蜍中脑视叶白介素1α (IL-1α),干扰素γ(IFN-γ)和肿瘤坏死因子α(TNF-α)免疫阳性细胞的形态和分布特点,以丰富细胞因子在两栖类神经系统表达的情况,为进一步研究细胞因子对中枢神经系统的作用积累材料.方法:采用免疫组织化学SABC法和Nissl法对中华蟾蜍中脑视叶切片进行显色,光镜观察并进行统计分析处理.结果:IL-1α和IFN-γ阳性细胞在中脑视叶顶盖和被盖都有很多分布,为大、中和小型细胞,而且以中、小型细胞为主,胞体为圆形和似锥形,另外顶盖带状层出现2亚层的阳性纤维;TNF-α阳性细胞只分布在中脑视叶被盖背侧区,都为中、小型细胞,胞体圆形. 结论:IL-1α和IFN-γ阳性细胞广泛分布中华蟾蜍中脑视叶各区,

  6. Decline of electrogenic Na+/K+ pump activity in rod photoreceptors during maintained illumination

    OpenAIRE

    1986-01-01

    Light-evoked changes in membrane voltage were recorded intracellularly from rod photoreceptors in the isolated retina preparation of the toad, Bufo marinus, during superfusion with a solution containing pharmacological agents that blocked voltage-dependent conductances. Under these conditions, the amplitude of the hyperpolarizing photoresponse became much greater than under control conditions. The results of several experiments support the conclusion that this increase in photoresponse amplit...

  7. Studies on the Effects of Deltamethrin on Sodium Net Transport Through the in vivo Amphibian Skin

    Institute of Scientific and Technical Information of China (English)

    ALFREDOSALIBIAN; JOSEL.MARAZZO

    1995-01-01

    The action of micromolar concentrations of Deltamethrin on sodium net transport through the in vivo skin of the South American toad Bufo arenarum was studied.The effect or pure ethanolic insecticide solutions and commercial formulations when applied on the mucosal surface was assayed.Deltamethrin provoked a concentration-independent inhibition;the highest inhibition was found at the lowest concentrations.At highest concentrations of the insecticide the Jn Na was not altered.

  8. Evolution of erythrocyte morphology in amphibians (Amphibia: Anura)

    OpenAIRE

    Jie Wei; Yan-Yan Li; Li Wei; Guo-Hua Ding; Xiao-Li Fan; Zhi-Hua Lin

    2015-01-01

    ABSTRACT We compared the morphology of the erythrocytes of five anurans, two toad species - Bufo gargarizans (Cantor, 1842) and Duttaphrynus melanostictus (Schneider, 1799) and three frog species - Fejervarya limnocharis (Gravenhorst, 1829), Microhyla ornata (Duméril & Bibron, 1841), and Rana zhenhaiensis (Ye, Fei & Matsui, 1995). We then reconstructed the ancestral state of erythrocyte size (ES) and nuclear size (NS) in amphibians based on a molecular tree. Nine morphological traits of eryth...

  9. Developmental alterations and osmoregulatory physiology of a larval anuran under osmotic stress

    OpenAIRE

    Gómez-Mestre, Iván; Tejedo, Miguel; Ramayo E.; Estepa, J.

    2004-01-01

    Water salinity represents an environmental stress for many species. Amphibians are particularly sensitive because they are generally poor osmoregulators, and most species are completely absent from brackish and saline environments. We experimentally examined the effect of different salinity levels on larvae of the toad Bufo calamita L., a species that occupies freshwater ponds but can also breed in brackish ponds. Two independent experiments are reported here. In both experiments, tadpoles un...

  10. Nematodes of amphibians from Java, Indonesia, with a description of new species, Meteterakis wonosoboensis n. sp. (Nematoda : Heterakoidea).

    Science.gov (United States)

    Purwaningsih, Endang; Dewi, Kartika; Hasegawa, Hideo

    2015-06-24

    During a survey on the parasites of amphibians of Indonesia, toads (30 Bufo melanostictus) and 246 frogs (213 Fejervarya cancrivora, 11 F. limnocharis, 22 Rana macrodon from West Java and 68 F. cancrivora from Central Java) were examined for parasitic nematodes. Three species of nematodes were found and described, i.e. Meteterakis wonosoboensis n. sp. from Fejervaria cancrivora; Meteterakis japonica from Bufo melanostictus, F. cancrivora and F. limnocharis; and Chabaudus sp. from F. cancrivora, F. limnocharis and Rana macrodon. Meteterakis wonosoboensis n. sp. is distinguished from other species of the genus by the length and shape of spicules, the number of caudal papillae, the presence of gubernaculum in male and the presence of vulval flap in female. Bufo melanostictus and Java are recorded as new host and locality for M. japonica, respectively.

  11. Haplometra cylindracea (Zeder, 1800 (Trematoda: Plagiorchiidae: variation in the dates of cercarial shedding for overwintering Galba truncatula

    Directory of Open Access Journals (Sweden)

    Vignoles P.

    2011-05-01

    Full Text Available Natural infections of Galba truncatula with Haplometra cylindracea were followed from 2001 to 2009 to determine if their characteristics were similar when snails came from water collections frequented by Bufo bufo or by frogs and newts for their egg-laying. Snail samples were collected from both types of sites to count shed cercariae for three days and also free cercariae when snails were dissected. In sites only frequented by B. bufo, cercarial shedding occurred earlier than in those colonized by frogs and newts (March instead of April-May. In contrast, the number of cercariae shed during three successive days was significantly higher in May. This variation in the dates of cercarial shedding might be due, either to a synchronism between cercaria-releasing snails and the presence of the definitive host (tadpoles in water collections, or to an earlier infection of overwintering snails in autumn by H. cylindracea miracidia in the case of toad-frequented sites.

  12. Rediscovery of Pelobates fuscus insubricus in the Asti Province, north-western Italy

    Directory of Open Access Journals (Sweden)

    Vincenzo Mercurio

    2007-01-01

    Full Text Available The amphibians of the pond complex “Stagni di Belangero” in the Po Plain, Asti Province, have been studied. The species living in the pond are Bufo bufo, Bufo viridis, Hyla intermedia, Pelobates fuscus, Rana dalmatina, Rana synklepton esculenta, Rana cf. kurtmuelleri, Triturus carnifex and Triturus vulgaris. Species composition, migration period of P. fuscus, and biometric data are provided. Relevant importance has been given to P. fuscus, since we reconfirm its presence in one of the ponds 13 years after its first finding in the area. This toad is also one of the most threatened species of amphibians in Europe and needs particular attention in order to be protected adequately.

  13. Cattle grazing and conservation of a meadow-dependent amphibian species in the Sierra Nevada.

    Directory of Open Access Journals (Sweden)

    Leslie M Roche

    Full Text Available World-wide population declines have sharpened concern for amphibian conservation on working landscapes. Across the Sierra Nevada's national forest lands, where almost half of native amphibian species are considered at risk, permitted livestock grazing is a notably controversial agricultural activity. Cattle (Bos taurus grazing is thought to degrade the quality, and thus reduce occupancy, of meadow breeding habitat for amphibian species of concern such as the endemic Yosemite toad (Anaxyrus [ = Bufo] canorus. However, there is currently little quantitative information correlating cattle grazing intensity, meadow breeding habitat quality, and toad use of meadow habitat. We surveyed biotic and abiotic factors influencing cattle utilization and toad occupancy across 24 Sierra Nevada meadows to establish these correlations and inform conservation planning efforts. We utilized both traditional regression models and Bayesian structural equation modeling to investigate potential drivers of meadow habitat use by cattle and Yosemite toads. Cattle use was negatively related to meadow wetness, while toad occupancy was positively related. In mid and late season (mid July-mid September grazing periods, cattle selected for higher forage quality diets associated with vegetation in relatively drier meadows, whereas toads were more prevalent in wetter meadows. Because cattle and toads largely occupied divergent zones along the moisture gradient, the potential for indirect or direct negative effects is likely minimized via a partitioning of the meadow habitat. During the early season, when habitat use overlap was highest, overall low grazing levels resulted in no detectable impacts on toad occupancy. Bayesian structural equation analyses supported the hypothesis that meadow hydrology influenced toad meadow occupancy, while cattle grazing intensity did not. These findings suggest cattle production and amphibian conservation can be compatible goals within this

  14. 浙江丽水中华大蟾蜍和黑眶蟾蜍蝌蚪对水位变化的表型响应%Phenotypic responses to water level change in Bufo gargarizans and Duttaphrynus melanosticus tadpoles at Lishui, Zhejiang

    Institute of Scientific and Technical Information of China (English)

    唐小芬; 樊晓丽; 林植华; 姚婷婷; 李香; 金晶; 周存通

    2015-01-01

    全球气候变暖引发栖息地干涸将对生活在水中的无尾类幼体提出了挑战.通过浙江丽水中华大蟾蜍(Bufo gargarizans)和黑眶蟾蜍(Duttaphrynus melanosticus)蝌蚪在实验条件下对不同水位变化的表型响应,检测表型可塑性的遗传性和环境近因性影响.结果表明,水位变化对中华大蟾蜍蝌蚪早期发育历期、头宽和体重影响不显著,对体长影响显著,其中逐减水位最大、恒低水位最小,慢波、恒高与快波、逐增水位依次减少;水位变化对黑眶蟾蜍蝌蚪早期发育历期、体长、头宽和体重影响均显著;发育历期以恒高水位最大,恒低水位最小;体长以逐减水位最大,恒低、快波和慢波水位显著偏小,逐增和快波水位居中;头宽以恒低水位最小,逐增水位居中,其余较大;体重以恒低水位最小、恒高水位最大,其余居中.水位变化对中华大蟾蜍蝌蚪的变态时间、体长、头宽和体重影响均不显著;水位变化对黑眶蟾蜍蝌蚪的变态时间、体长和体重影响均显著,对头宽影响不显著;恒低水位的变态时间最长,恒高水位的变态时间最短,其他水位变化之间差异不显著;恒高水位的体长最大,恒低和快波水位最小,其他居中;逐增和快波水位的体重最大,恒低水位最小.研究结果表明,繁殖季节不同的中华大蟾蜍和黑眶蟾蜍蝌蚪响应水位变化的表型可塑性差异显著,长期在容易发生干旱和水位变化的冬季繁殖的中华大蟾蜍蝌蚪的表型可塑性低,在雨水充沛的春季繁殖的黑眶蟾蜍蝌蚪的表型可塑性高,表现出表型可塑性的种间差异和遗传性;在早期发育过程中,两种蝌蚪体长的共同的表型变异与缺乏遗传基础的环境近因性影响有关;黑眶蟾蜍蝌蚪对低水位或水位下降作出减速分化的消极响应,响应程度与环境信号的强弱直接相关.

  15. Toads Give You Warts--Not!

    Science.gov (United States)

    Tomasek, Terry; Matthews, Catherine E.

    2008-01-01

    The authors provide activities through which teachers can share experiences in the outdoors with young children and teach them about herpetology, the study of amphibians and reptiles. Outdoor activities include observation, classification, and mapping. The authors also include activities for the classroom, including connections between the science…

  16. Arroyo Toad Range - CWHR [ds612

    Data.gov (United States)

    California Department of Resources — Vector datasets of CWHR range maps are one component of California Wildlife Habitat Relationships (CWHR), a comprehensive information system and predictive model...

  17. 鲜蟾皮外敷促进糖尿病大鼠皮肤溃疡愈合的实验研究%An experimental study of the promotion of healing of skin ulcers in diabetic rats by external application of fresh toad skin

    Institute of Scientific and Technical Information of China (English)

    张晓义; 唐祝奇; 刘春; 朱晓晖; 印彤; 王粹芳; 崔世维

    2013-01-01

    Objective: To study the effect of the treatment of skin ulcers in diabetic rats by external application of fresh toad skin and its possible mechanism of action. Methods: 42 male SD rats were randomly divided into three groups:the normal control group (12 rats), the diabetic skin ulcers model group (15 rats), and the diabetic skin ulcers treatment group (15 rats). A model of skin ulcers in rats was created, then fresh toad skin was applied on these ulcer sites, and how the ulcers got healed was observed. Pathologically, the wounded tissue structures around the ulcers were observed at the 2nd and 3rd weekends, and immunohistochemically, the expression of the wounded tissue vascular endothelial growth factor (VEGF) was observed. Results: Ulcers began to shrink after 2 weeks and scab after 3 weeks in the diabetic model group. By contrast, in the diabetic treatment group, the expression of VEGF was increased (15.6±2.2 μg/g vs. 48.3±4.2 μg/g, P<0.05) at the end of 2 weeks and sustained to the end of 3 weeks (19.5±3.2μg/g vs. 10.9±2.7μg/g, P<0.05), and meanwhile the wound healing cycle was shortened. Conclusions:External application of fresh toad skin can increase the expression of the wounded tissues VEGF and promote the healing of skin ulcers in diabetic rats.%目的:研究鲜蟾皮外敷对糖尿病大鼠皮肤溃疡的治疗作用及作用机制。方法:清洁级雄性SD大鼠42只,分为3组:正常对照组(12只)、糖尿病皮肤溃疡模型组(15只)、糖尿病皮肤溃疡治疗组(15只)。建立缺损性皮肤溃疡大鼠模型,鲜蟾皮外敷溃疡部位,观察溃疡愈合情况;大体病理观察第2、3周末溃疡组织结构,免疫组化观察血管内皮生长因子(VEGF)的表达,酶联免疫反应技术测定组织中VEGF含量。结果:模型组2周溃疡开始缩小,3周结痂,与对照组相比VEGF表达降低(15.6±2.2μg/g vs.48.3±4.2μg/g, P<0.05);与模型组相比,治疗组2

  18. Farmed areas predict the distribution of amphibian ponds in a traditional rural landscape.

    Directory of Open Access Journals (Sweden)

    Tibor Hartel

    Full Text Available BACKGROUND: Traditional rural landscapes of Eastern Europe are undergoing major changes due to agricultural intensification, land abandonment, change in agricultural practices and infrastructural development. Small man-made ponds are important yet vulnerable components of rural landscapes. Despite their important role for biodiversity, these ponds tend to be excluded from conservation strategies. METHODOLOGY/FINDINGS: Our study was conducted in a traditional rural landscape in Eastern Europe. The aim of this study is twofold: (i to model the distribution of four major man-made pond types and (ii to present the importance of man-made ponds for the endangered Yellow Bellied Toad (Bombina variegata and the Common Toad (Bufo bufo. Six environmental variables were used to model pond distribution: Corine landcover, the heterogeneity of the landcover, slope, road distance, distance to closest village and the human population density. Land cover heterogeneity was the most important driver for the distribution of fishponds. Areas used for agriculture with significant areas of natural vegetation were the most important predictors for the distribution of temporary ponds. In addition, areas covered by transitional woodland and scrub were important for the open cattle ponds. Bombina variegata was found predominantly in the temporary ponds (e.g. ponds created by cattle and buffalo, dirt road ponds and concrete ponds created for livestock drinking and Bufo bufo in fishponds. CONCLUSIONS/SIGNIFICANCE: Our Maxent models revealed that the highest probability of occurrence for amphibian ponds was in areas used as farmland. The traditional farming practices combined with a low level of infrastructure development produces a large number of amphibian ponds. The challenge is to harmonize economic development and the maintenance of high densities of ponds in these traditional rural landscapes.

  19. How Preussag Became TUI : Kissing Too Many Toads Can Make You a Toad

    NARCIS (Netherlands)

    I. Dittmann (Ingolf); E.G. Maug (Ernst); C. Schneider (Christoph)

    2006-01-01

    textabstractIn the period 1997-2004, Preussag, a diversified German conglomerate of old economy businesses, changed itself into TUI, a company focused almost entirely on tourism and logistics. This paper analyzes how this strategy was executed and how it contributed to Preussag's underperformance of

  20. Environ: E00121 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available E00121 Toad venom (JP16) Crude drug Hellebrin [CPD:C08868], Resibufogenin [CPD:C170...58], Cinobufagin [CPD:C16931], Bufalin [CPD:C16922], Bufotalin [CPD:C16923], Cinobufotalin [CPD:C16932], Gamabufo...talin [CPD:C16962], Telocinobufagin [CPD:C17072], Hellebrigenin [CPD:C16969], Bufadienolides [CPD:C16921], Cardenolides, Bufo...tenine [CPD:C08299], Bufotenidine [CPD:C13664], Epirenamine...l, Marinobufagin, Resibufagin, Serotonine, Bufothionine, Dehydrobufotenine, Bufotoxin, Cholesterol [CPD:C001

  1. Homeotic regeneration of eye in amphibian tadpoles and its enhancement by vitamin A

    Indian Academy of Sciences (India)

    O P Jangir; D V S Shekhawat; Acharya Prakash; K K Swami; Pawan Suthar

    2001-12-01

    After removal of both the lateral eyes of external gill stage tadpoles of the toad Bufo melanostictus, the pineal organ gets transformed into a median eye. This type of transformation occurrs in tadpoles of both control and vitamin A treated groups. However, vitamin A increases the likelihood of homeotic regeneration (57% in the control group and 71% in the vitamin A treated group). Histological studies showed that the newly transformed median eye developed from the pineal organ. The pineal eye so developed possessed all components of a normal eye such as a retina, sensory cells and lens.

  2. Amphibians and disease: Implications for conservation in the Greater Yellowstone Ecosystem

    Science.gov (United States)

    Corn, P.S.

    2007-01-01

    The decline of amphibian populations is a world-wide phenomenon that has received increasing attention since about 1990. In 2004, the World Conservation Union’s global amphibian assessment concluded that 48% of the world’s 5,743 described amphibian species were in decline, with 32% considered threatened (Stuart et al. 2004). Amphibian declines are a significant issue in the western United States, where all native species of frogs in the genus Rana and many toads in the genus Bufo are at risk, particularly those that inhabit mountainous areas (Corn 2003a,b; Bradford 2005).

  3. Thubunaea dactyluris Sensu Fabio and Rolas, a synonym of Physalopteroides venancioi (Spirurida, Physalopteridae).

    Science.gov (United States)

    Vrcibradic, D; Vicente, J J; Bursey, C R

    2000-10-01

    Specimens of Thubunaea dactyluris Karve, 1938 sensu Fabio and Rolas, 1974 from the lizard Ameiva ameiva of Brazil and types of Physalopteroides venancioi (Lent, Freitas, and Proença, 1946) from the toad Bufo paracnemis of Paraguay were re-examined. The male caudal papillae and the tooth arrangement demonstrated that these specimens were conspecific and are all assigned to P. venancioi. The occurrence of Physalopteroides dactyluris (Karve, 1938), a nematode parasite of lizards of India and Turkmenistan, is invalidated for Brazil. PMID:11128504

  4. Studies of Annual and Seasonal Variations in Four Species of Reptiles and Amphibians at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Keller, D.C.; Nelson, E.I.; Mullen, M.A.; Foxx, T.S.; Haarmann, T.K.

    1998-07-01

    Baseline studies of reptiles and amphibians of the Pajarito wetlands at Los Alamos National Laboratory have been conducted by the Ecology group since 1990. With the data gathered from 1990-1997 (excluding 1992), we examined the annual and seasonal population changes of four species of reptiles and amphibians over the past seven years. The four species studied are the Woodhouse toad (Bufo woodhousii), the western chorus frog (Pseudacris triseriata), the many-lined skink (Eunzeces nudtivirgatus), and the plateau striped whiptail lizard (Cnemidophorus velox). Statistical analyses indicate a significant change on a seasonal basis for the western chorus frog and the many-lined skink. Results indicate a significant difference in the annual population of the Woodhouse toad.

  5. Experimental evidence for beneficial effects of projected climate change on hibernating amphibians

    Science.gov (United States)

    Üveges, Bálint; Mahr, Katharina; Szederkényi, Márk; Bókony, Veronika; Hoi, Herbert; Hettyey, Attila

    2016-01-01

    Amphibians are the most threatened vertebrates today, experiencing worldwide declines. In recent years considerable effort was invested in exposing the causes of these declines. Climate change has been identified as such a cause; however, the expectable effects of predicted milder, shorter winters on hibernation success of temperate-zone Amphibians have remained controversial, mainly due to a lack of controlled experimental studies. Here we present a laboratory experiment, testing the effects of simulated climate change on hibernating juvenile common toads (Bufo bufo). We simulated hibernation conditions by exposing toadlets to current (1.5 °C) or elevated (4.5 °C) hibernation temperatures in combination with current (91 days) or shortened (61 days) hibernation length. We found that a shorter winter and milder hibernation temperature increased survival of toads during hibernation. Furthermore, the increase in temperature and shortening of the cold period had a synergistic positive effect on body mass change during hibernation. Consequently, while climate change may pose severe challenges for amphibians of the temperate zone during their activity period, the negative effects may be dampened by shorter and milder winters experienced during hibernation. PMID:27229882

  6. Linking global warming to amphibian declines through its effects on female body condition and survivorship.

    Science.gov (United States)

    Reading, C J

    2007-02-01

    There is general consensus that climate change has contributed to the observed decline, and extinction, of many amphibian species throughout the world. However, the mechanisms of its effects remain unclear. A laboratory study in 1980-1981 in which temperate zone amphibians that were prevented from hibernating had decreased growth rates, matured at a smaller size and had increased mortality compared with those that hibernated suggested one possible mechanism. I used data from a field study of common toads (Bufo bufo) in the UK, between 1983 and 2005, to determine whether this also occurs in the field. The results demonstrated two pathways by which global warming may cause amphibian declines. First, there was a clear relationship between a decline in the body condition of female common toads and the occurrence of warmer than average years since 1983. This was paralleled by a decline in their annual survival rates with the relationship between these two declines being highly correlated. Second, there was a significant relationship between the occurrence of mild winters and a reduction in female body size, resulting in fewer eggs being laid annually. Climate warming can, therefore, act on wild temperate zone amphibians by deleteriously affecting their physiology, during and after hibernation, causing increased female mortality rates and decreased fecundity in survivors.

  7. Experimental evidence for beneficial effects of projected climate change on hibernating amphibians.

    Science.gov (United States)

    Üveges, Bálint; Mahr, Katharina; Szederkényi, Márk; Bókony, Veronika; Hoi, Herbert; Hettyey, Attila

    2016-05-27

    Amphibians are the most threatened vertebrates today, experiencing worldwide declines. In recent years considerable effort was invested in exposing the causes of these declines. Climate change has been identified as such a cause; however, the expectable effects of predicted milder, shorter winters on hibernation success of temperate-zone Amphibians have remained controversial, mainly due to a lack of controlled experimental studies. Here we present a laboratory experiment, testing the effects of simulated climate change on hibernating juvenile common toads (Bufo bufo). We simulated hibernation conditions by exposing toadlets to current (1.5 °C) or elevated (4.5 °C) hibernation temperatures in combination with current (91 days) or shortened (61 days) hibernation length. We found that a shorter winter and milder hibernation temperature increased survival of toads during hibernation. Furthermore, the increase in temperature and shortening of the cold period had a synergistic positive effect on body mass change during hibernation. Consequently, while climate change may pose severe challenges for amphibians of the temperate zone during their activity period, the negative effects may be dampened by shorter and milder winters experienced during hibernation.

  8. Linking global warming to amphibian declines through its effects on female body condition and survivorship.

    Science.gov (United States)

    Reading, C J

    2007-02-01

    There is general consensus that climate change has contributed to the observed decline, and extinction, of many amphibian species throughout the world. However, the mechanisms of its effects remain unclear. A laboratory study in 1980-1981 in which temperate zone amphibians that were prevented from hibernating had decreased growth rates, matured at a smaller size and had increased mortality compared with those that hibernated suggested one possible mechanism. I used data from a field study of common toads (Bufo bufo) in the UK, between 1983 and 2005, to determine whether this also occurs in the field. The results demonstrated two pathways by which global warming may cause amphibian declines. First, there was a clear relationship between a decline in the body condition of female common toads and the occurrence of warmer than average years since 1983. This was paralleled by a decline in their annual survival rates with the relationship between these two declines being highly correlated. Second, there was a significant relationship between the occurrence of mild winters and a reduction in female body size, resulting in fewer eggs being laid annually. Climate warming can, therefore, act on wild temperate zone amphibians by deleteriously affecting their physiology, during and after hibernation, causing increased female mortality rates and decreased fecundity in survivors. PMID:17024381

  9. Experimental evidence for beneficial effects of projected climate change on hibernating amphibians.

    Science.gov (United States)

    Üveges, Bálint; Mahr, Katharina; Szederkényi, Márk; Bókony, Veronika; Hoi, Herbert; Hettyey, Attila

    2016-01-01

    Amphibians are the most threatened vertebrates today, experiencing worldwide declines. In recent years considerable effort was invested in exposing the causes of these declines. Climate change has been identified as such a cause; however, the expectable effects of predicted milder, shorter winters on hibernation success of temperate-zone Amphibians have remained controversial, mainly due to a lack of controlled experimental studies. Here we present a laboratory experiment, testing the effects of simulated climate change on hibernating juvenile common toads (Bufo bufo). We simulated hibernation conditions by exposing toadlets to current (1.5 °C) or elevated (4.5 °C) hibernation temperatures in combination with current (91 days) or shortened (61 days) hibernation length. We found that a shorter winter and milder hibernation temperature increased survival of toads during hibernation. Furthermore, the increase in temperature and shortening of the cold period had a synergistic positive effect on body mass change during hibernation. Consequently, while climate change may pose severe challenges for amphibians of the temperate zone during their activity period, the negative effects may be dampened by shorter and milder winters experienced during hibernation. PMID:27229882

  10. Why are some mitochondria more powerful than others: insights from comparisons of muscle mitochondria from three terrestrial vertebrates.

    Science.gov (United States)

    Guderley, Helga; Turner, Nigel; Else, Paul L; Hulbert, A J

    2005-10-01

    We studied the molecular composition of muscle mitochondria to evaluate whether the contents of cytochromes or adenine nucleotide translocase (ANT) or phospholipid acyl compositions reflect differences in mitochondrial oxidative capacities. We isolated mitochondria from three vertebrates of similar size and preferred temperature, the rat (Rattus norvegicus), the cane toad (Bufo marinus) and the bearded dragon lizard (Pogona vitticeps). Mitochondrial oxidative capacities were higher in rats and cane toads than in bearded dragon, whether rates were expressed relative to protein, cytochromes or ANT. Inter-specific differences were least pronounced when rates were expressed relative to cytochrome A, a component of cytochrome C oxidase (CCO), or ANT. In mitochondria from rat and cane toad, cytochrome A was more abundant than C followed by B and then C(1), while in bearded dragon mitochondria, the cytochromes were present in roughly equal levels. Analysis of correlations between mitochondrial oxidative capacities and macromolecular components revealed that cytochrome A explained at least half of the intra- and inter-specific variability in substrate oxidation rates. ANT levels were an excellent correlate of state 3 rates while phospholipid contents were correlated with state 4 rates. As the % poly-unsaturation and the % 20:4n-6 in mitochondrial phospholipids were equivalent in toads and rats, and exceeded the levels in lizards, they may contribute to the inter-specific differences in oxidative capacities. We suggest that the numbers of CCO and ANT together with the poly-unsaturation of phospholipids explain the higher oxidative capacities in muscle mitochondria from rats and cane toads. PMID:16085440

  11. Toxicity of a glufosinate- and several glyphosate-based herbicides to juvenile amphibians from the Southern High Plains, USA.

    Science.gov (United States)

    Dinehart, Simon K; Smith, Loren M; McMurry, Scott T; Anderson, Todd A; Smith, Philip N; Haukos, David A

    2009-01-15

    Pesticide toxicity is often proposed as a contributing factor to the world-wide decline of amphibian populations. We assessed acute toxicity (48 h) of a glufosinate-based herbicide (Ignite 280 SL) and several glyphosate-based herbicide formulations (Roundup WeatherMAX, Roundup Weed and Grass Killer Super Concentrate, Roundup Weed and Grass Killer Ready-To-Use Plus on two species of amphibians housed on soil or moist paper towels. Survival of juvenile Great Plains toads (Bufo cognatus) and New Mexico spadefoots (Spea multiplicata) was reduced by exposure to Roundup Weed and Grass Killer Ready-To-Use Plus on both substrates. Great Plains toad survival was also reduced by exposure to Roundup Weed and Grass Killer Super Concentrate on paper towels. New Mexico spadefoot and Great Plains toad survival was not affected by exposure to the two agricultural herbicides (Roundup WeatherMAX and Ignite 280 SL) on either substrate, suggesting that these herbicides likely do not pose an immediate risk to these species under field conditions. PMID:19000631

  12. Insulin-stimulated Na+ transport in a model renal epithelium: protein synthesis dependence and receptor interactions

    International Nuclear Information System (INIS)

    The urinary bladder of the toad, Bufo marinus, is a well characterized model of the mammalian distal nephron. Porcine insulin (∼ 0.5-5.0 μM) stimulates net mucosal to serosal Na+ flux within 10 minutes of hormone addition. The response is maintained for at least 5 hr and is completely abolished by low doses (10μM) of the epithelial Na+ channel blocker amiloride. Insulin-stimulated Na+ transport does not require new protein synthesis since it is actinomycin-D (10μg/ml) insensitive. Also in 3 separate experiments in which epithelial cell proteins were examined by 35S-methionine labeling, 2-dimensional polyacrylamide gel electrophoresis/autoradiography, no insulin induced proteins were observed. Equimolar concentrations of purified porcine proinsulin and insulin (0.64μM) stimulate Na+ transport to the same extent. Thus, the putative toad insulin receptor may have different affinity characteristics than those demonstrated for insulin and proinsulin in mammalian tissues. Alternatively, the natriferic action of insulin in toad urinary bladders may be mediated by occupancy of another receptor. Preliminary experiments indicating that nanomolar concentrations of IGF1 stimulate Na+ transport in this tissue support the latter contention

  13. Insulin-stimulated Na/sup +/ transport in a model renal epithelium: protein synthesis dependence and receptor interactions

    Energy Technology Data Exchange (ETDEWEB)

    Blazer-Yost, B.L.; Cox, M.

    1987-05-01

    The urinary bladder of the toad, Bufo marinus, is a well characterized model of the mammalian distal nephron. Porcine insulin (approx. 0.5-5.0 ..mu..M) stimulates net mucosal to serosal Na/sup +/ flux within 10 minutes of hormone addition. The response is maintained for at least 5 hr and is completely abolished by low doses (10..mu..M) of the epithelial Na/sup +/ channel blocker amiloride. Insulin-stimulated Na/sup +/ transport does not require new protein synthesis since it is actinomycin-D (10..mu..g/ml) insensitive. Also in 3 separate experiments in which epithelial cell proteins were examined by /sup 35/S-methionine labeling, 2-dimensional polyacrylamide gel electrophoresis/autoradiography, no insulin induced proteins were observed. Equimolar concentrations of purified porcine proinsulin and insulin (0.64..mu..M) stimulate Na/sup +/ transport to the same extent. Thus, the putative toad insulin receptor may have different affinity characteristics than those demonstrated for insulin and proinsulin in mammalian tissues. Alternatively, the natriferic action of insulin in toad urinary bladders may be mediated by occupancy of another receptor. Preliminary experiments indicating that nanomolar concentrations of IGF/sub 1/ stimulate Na/sup +/ transport in this tissue support the latter contention.

  14. Control of adipose tissue lipolysis in ectotherm vertebrates.

    Science.gov (United States)

    Migliorini, R H; Lima-Verde, J S; Machado, C R; Cardona, G M; Garofalo, M A; Kettelhut, I C

    1992-10-01

    Lipolytic activity of fish (Hoplias malabaricus), toad (Bufo paracnemis), and snake (Philodryas patagoniensis) adipose tissue was investigated in vivo and in vitro. Catecholamines or glucagon did not affect the release of free fatty acids (FFA) by incubated fish and toad adipose tissue. Catecholamines also failed to activate snake adipose tissue lipolysis, which even decreased in the presence of epinephrine. However, glucagon stimulated both the lipolytic activity of reptilian tissue in vitro and the mobilization of FFA to plasma when administered to snakes in vivo. The release of FFA from incubated fish, amphibian, and reptilian adipose tissue increased markedly in the presence of cAMP or xanthine derivatives, inhibitors of phosphodiesterase. Forskolin or fluoride, activators of specific components of the adenylate cyclase system, strongly stimulated toad adipose tissue lipolysis. The data suggest that adipocyte triacylglycerol lipase of ectotherm vertebrates is activated by a cAMP-mediated phosphorylation and that the organization of the membrane-bound adenylate cyclase system is similar to that of mammals. PMID:1329567

  15. Sympatric Masticophis flagellum and Coluber constrictor select vertebrate prey at different levels of taxonomy

    Science.gov (United States)

    Halstead, B.J.; Mushinsky, H.R.; McCoy, E.D.

    2008-01-01

    Masticophis flagellum (Coachwhip) and Coluber constrictor (Eastern Racer) are widespread North American snakes with similar foraging modes and habits. Little is known about the selection of prey by either species, and despite their apparently similar foraging habits, comparative studies of the foraging ecology of sympatric M. flagellum and C. constrictor are lacking. We examined the foraging ecology and prey selection of these actively foraging snakes in xeric, open-canopied Florida scrub habitat by defining prey availability separately for each snake to elucidate mechanisms underlying geographic, temporal, and interspecific variation in predator diets. Nineteen percent of M. flagellum and 28% of C. constrictor contained stomach contents, and most snakes contained only one prey item. Mean relative prey mass for both species was less than 10%. Larger C. constrictor consumed larger prey than small individuals, but this relationship disappeared when prey size was scaled to snake size. Masticophis flagellum was selective at the prey category level, and positively selected lizards and mammals; however, within these categories it consumed prey species in proportion to their availability. In contrast, C. constrictor preyed upon prey categories opportunistically, but was selective with regard to species. Specifically, C. constrictor positively selected Hyla femoralis (Pine Woods Treefrog) and negatively selected Bufo querclcus (Oak Toad), B. terrestris (Southern Toad), and Gastrophryne carolinensis (Eastern Narrowmouth Toad). Thus, despite their similar foraging habits, M. flagellum and C. constrictor select different prey and are selective of prey at different levels of taxonomy. ?? 2008 by the American Society of Ichthyologists and Herpetologists.

  16. Anticipatory motor patterns limit muscle stretch during landing in toads

    OpenAIRE

    Azizi, Emanuel; Abbott, Emily M.

    2013-01-01

    To safely land after a jump or hop, muscles must be actively stretched to dissipate mechanical energy. Muscles that dissipate energy can be damaged if stretched to long lengths. The likelihood of damage may be mitigated by the nervous system, if anticipatory activation of muscles prior to impact alters the muscle's operating length. Anticipatory motor recruitment is well established in landing studies and motor patterns have been shown to be modulated based on the perceived magnitude of the i...

  17. Sodium recirculation and isotonic transport in toad small intestine

    DEFF Research Database (Denmark)

    Nedergaard, Signe Nielsen; Larsen, Erik Hviid; Ussing, Hans H.

    1999-01-01

    Small intestine; leaky epithelia; solute-coupled water transport; Na*O+ recirculation; lateral intercellular space; flux ratio analysi......Small intestine; leaky epithelia; solute-coupled water transport; Na*O+ recirculation; lateral intercellular space; flux ratio analysi...

  18. Teaduslikud töötoad osutusid magnetiks / Martin Pau

    Index Scriptorium Estoniae

    Pau, Martin, 1975-

    2011-01-01

    Haridus- ja teadusministeeriumilt teaduse ja tehnoloogia populariseerimise eest preemia saanud maaülikooli doktorantide projekti «Elus teadus» õpitubades osales esimese kolme kuuga üle 800 koolilapse

  19. Disappearance of boreal toads in Colorado: A contaminant investigation

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Population sizes of many, but not all, amphibian species have experienced declines on all six continents on which they occur (Phillips 1990, Vial and Saylor 1993)....

  20. Evolutionary reduction of developmental plasticity in desert spadefoot toads

    OpenAIRE

    Kulkarni, S.R.; Gómez-Mestre, Iván; Moskalik, C.L.; Storz, B.L.; Buchholz, D.R.

    2011-01-01

    Organisms vary their rates of growth and development in response to environmental inputs. Such developmental plasticity may be adaptive and positively correlate with environmental heterogeneity. However, the evolution of developmental plasticity among closely related taxa is not well understood. To determine the evolutionary pattern of plasticity, we compared plasticity in time to and size at metamorphosis in response to water desiccation in tadpoles among spadefoot species that differ in bre...

  1. Middle Breton prezeffan 'vermin, toad, lizard'

    DEFF Research Database (Denmark)

    Jørgensen, Anders Richardt

    2012-01-01

    Middelbretonsk prezeffan, hidtil set som en uforklaret variant af preffan 'kryb' (diminutiv af preff 'orm'), tolkes nu i stedet som et selvstændigt leksem. Det afledes af et ældre *pezreffan, som svarer direkte til kornisk pedrevan 'firben'. En videre analyse identificerer første del af ordet som...

  2. A Stylistic Analysis of Philip Larkin’s Toads

    Institute of Scientific and Technical Information of China (English)

    Fu Yanli

    2013-01-01

    This paper analyzes the stylistic features of the poem “Toads” written by Philip Larkin. This paper focuses on the stylistic features: lexis, grammar, rhetorical devices, phonetics and so on. At the end of this paper, some interpretations wil be made to il ustrate the importance of stylistics to poetry appreciation.

  3. All-Optical Reversible Hybrid New Gate using TOAD

    Directory of Open Access Journals (Sweden)

    Goutam Kumar Maity

    2014-03-01

    Full Text Available Reversible logic is emerged as a promising computing paradigm with applications in low-power CMOS, quantum computing, optical computing and nanotechnology. Optical logic gates become potential component to work at macroscopic (light pulses carry information, or quantum (single photon carries information levels with high efficiency. In this paper, we propose a novel scheme of Hybrid new gate realization in all-optical domain. Simulation results verify the functionality of the gate as well as reversibility. Approximate insertion power loss in dB is also reported for the Gaussian incident and control pulse.

  4. ФОРМИРОВАНИЕ ПОЧКИ У АМФИБИЙ В ЛИЧИНОЧНЫЙ ПЕРИОД РАЗВИТИЯ НА ПРИМЕРЕ ЖАБЫ ЗЕЛЕНОЙ (BUFO VIRIDIS LAURENTI, 1768)

    OpenAIRE

    СВЕТАШЕВА Д.Р.; ГРУШКО М.П.

    2014-01-01

    Описываются морфофизиологические особенности формирующегося мезонефроса у личинки зеленой жабы (Bufo viridis Laurenti, 1768). Определено, что изученный орган, наряду с функцией выделения, выполняет функцию кроветворения на протяжении личиночного периода развития. В почке образуются элементы крови всех линий. Основную долю формирующихся элементов крови на протяжении всего личиночного периода развития составляли клетки эритропоэтического ряда, далее, по мере убывания – гранулоцитопоэтические и ...

  5. Dipeptidyl peptidase-IV (DPP-IV inhibitory activity of parotid exudate of Bufo melanostictus

    Directory of Open Access Journals (Sweden)

    Allenki Venkatesham

    2009-01-01

    Full Text Available Type 2 diabetes arises as a result of β-cell failure combined with concomitant insulin resistance. Glucagon-like peptide-1 is a gastrointestinal hormone that is released postprandially from the L cells of the gut and exerts a glucose- dependent and direct insulinotropic effect on the pancreatic β cell. Which activate adenylate cyclase and enhances insulin secretion. GLP-1 is rapidly degraded by DPP-IV to GLP-1(9-37 amide following release from gut L cells. GLP-1 directly enhances glucose-dependent insulin secretion via an increase in β-cell cAMP. Dipeptidyl peptidase IV (DPP-IV is a plasma membrane glycoprotein ectopeptidase. In mammals, DPP-IV was widely expressed on the surface of endothelial and epithelial cells and highest levels in humans have been reported to occur in the intestine, bone marrow and kidney. Inhibiting DPP-IV reduces its rapid degradation of GLP-1, increasing circulating levels of the active hormone in vivo and prolonging its beneficial effects. The IC 50 value of parotid exudate was found to be 9.4 μg/ml. The maximum % inhibition (61.8 was showed at a concentration of 12μg/ml. Parotid exudate through inhibition of DPP-IV, improves glucose tolerance and enhances insulin secretion. DPP-IV inhibitors are a novel class of oral hypoglycemic agents with a potential to improve pancreatic beta cell function and the clinical course of type 2 diabetes.

  6. Ground Water Chemistry Changes before Major Earthquakes and Possible Effects on Animals

    Science.gov (United States)

    Grant, Rachel A.; Halliday, Tim; Balderer, Werner P.; Leuenberger, Fanny; Newcomer, Michelle; Cyr, Gary; Freund, Friedemann T.

    2011-01-01

    Prior to major earthquakes many changes in the environment have been documented. Though often subtle and fleeting, these changes are noticeable at the land surface, in water, in the air, and in the ionosphere. Key to understanding these diverse pre-earthquake phenomena has been the discovery that, when tectonic stresses build up in the Earth’s crust, highly mobile electronic charge carriers are activated. These charge carriers are defect electrons on the oxygen anion sublattice of silicate minerals, known as positive holes, chemically equivalent to O− in a matrix of O2−. They are remarkable inasmuch as they can flow out of the stressed rock volume and spread into the surrounding unstressed rocks. Travelling fast and far the positive holes cause a range of follow-on reactions when they arrive at the Earth’s surface, where they cause air ionization, injecting massive amounts of primarily positive air ions into the lower atmosphere. When they arrive at the rock-water interface, they act as •O radicals, oxidizing water to hydrogen peroxide. Other reactions at the rock-water interface include the oxidation or partial oxidation of dissolved organic compounds, leading to changes of their fluorescence spectra. Some compounds thus formed may be irritants or toxins to certain species of animals. Common toads, Bufo bufo, were observed to exhibit a highly unusual behavior prior to a M6.3 earthquake that hit L’Aquila, Italy, on April 06, 2009: a few days before the seismic event the toads suddenly disappeared from their breeding site in a small lake about 75 km from the epicenter and did not return until after the aftershock series. In this paper we discuss potential changes in groundwater chemistry prior to seismic events and their possible effects on animals. PMID:21776211

  7. Ground Water Chemistry Changes before Major Earthquakes and Possible Effects on Animals

    Directory of Open Access Journals (Sweden)

    Friedemann T. Freund

    2011-06-01

    Full Text Available Prior to major earthquakes many changes in the environment have been documented. Though often subtle and fleeting, these changes are noticeable at the land surface, in water, in the air, and in the ionosphere. Key to understanding these diverse pre-earthquake phenomena has been the discovery that, when tectonic stresses build up in the Earth’s crust, highly mobile electronic charge carriers are activated. These charge carriers are defect electrons on the oxygen anion sublattice of silicate minerals, known as positive holes, chemically equivalent to O– in a matrix of O2–. They are remarkable inasmuch as they can flow out of the stressed rock volume and spread into the surrounding unstressed rocks. Travelling fast and far the positive holes cause a range of follow-on reactions when they arrive at the Earth’s surface, where they cause air ionization, injecting massive amounts of primarily positive air ions into the lower atmosphere. When they arrive at the rock-water interface, they act as •O radicals, oxidizing water to hydrogen peroxide. Other reactions at the rock-water interface include the oxidation or partial oxidation of dissolved organic compounds, leading to changes of their fluorescence spectra. Some compounds thus formed may be irritants or toxins to certain species of animals. Common toads, Bufo bufo, were observed to exhibit a highly unusual behavior prior to a M6.3 earthquake that hit L’Aquila, Italy, on April 06, 2009: a few days before the seismic event the toads suddenly disappeared from their breeding site in a small lake about 75 km from the epicenter and did not return until after the aftershock series. In this paper we discuss potential changes in groundwater chemistry prior to seismic events and their possible effects on animals.

  8. [Effect of the heart electric stimulation on repolarization of fish and amphibian ventricular myocardium].

    Science.gov (United States)

    Azarov, Ia É; Kibler, N A; Vaĭshnoraĭte, M A; Tsvetkova, A S; Kharin, S N; Vitiazev, V A; Shmakov, D N

    2013-01-01

    By the method of synchronous multielectrode cartography (24-unipolar leads), distribution of durations and time of end of repolarization were studied on ventricular epicardium of pikes (Esox lucius) and frogs (Rana esculenta) and in ventricular intramural layers of toads (Bufo bufo) at the ectopic heart excitation. The time of arrival of the excitation wave and of the end of repolarization in each lead was determined from the minimum of time derivative of potential at the period of the QRS complex and by minimum of the T wave, respectively. It has been established that at the ventricle electrostimulation, alongside with deceleration and a change of sequence of the myocardium activation, there occurs redistribution of local repolarization durations: in areas of late activation the repolarization being longer than in zones of early activation (p < 0.05). At stimulation, the apicobasal gradient of repolarization is predominantly changed due to electrophysiological processes in the apical areas. In all studied species. at ectopical excitation of the heart ventricle the sequence of its repolarization repeats the depolarization sequence due to delay of activation (in fish) and redistribution of repolarization durations (in amphibians).

  9. A preliminary report of amphibian mortality patterns on railways

    Directory of Open Access Journals (Sweden)

    Karolina A. Budzik

    2014-06-01

    Full Text Available In contrast to road mortality, little is known about amphibian railroad mortality. The aim of this study was to quantify amphibian mortality along a railway line as well as to investigate the relationship between the availability of breeding sites in the surrounding habitats and the monthly variation of amphibian railway mortality. The study was conducted from April to July 2011 along 45 km of the railway line Kraków - Tarnów (Poland, Małopolska province. Three species were affected by railway mortality: Bufo bufo, Rana temporaria and Pelophylax kl. esculentus. Most dead individuals (77% were adult common toads. The largest number (14 of amphibian breeding sites was located in the most heterogeneous habitats (woodland and rural areas, which coincides with the sectors of highest amphibian mortality (42% of all accidents. As in the case of roads, spring migration is the period of highest amphibian mortality (87% of all accidents on railroads. Our findings suggest that railroad mortality depends on the agility of the species, associated primarily with the ability to overcome the rails.

  10. Applying fuzzy logic to comparative distribution modelling: a case study with two sympatric amphibians.

    Science.gov (United States)

    Barbosa, A Márcia; Real, Raimundo

    2012-01-01

    We modelled the distributions of two toads (Bufo bufo and Epidalea calamita) in the Iberian Peninsula using the favourability function, which makes predictions directly comparable for different species and allows fuzzy logic operations to relate different models. The fuzzy intersection between individual models, representing favourability for the presence of both species simultaneously, was compared with another favourability model built on the presences shared by both species. The fuzzy union between individual models, representing favourability for the presence of any of the two species, was compared with another favourability model based on the presences of either or both of them. The fuzzy intersections between favourability for each species and the complementary of favourability for the other (corresponding to the logical operation "A and not B") were compared with models of exclusive presence of one species versus the exclusive presence of the other. The results of modelling combined species data were highly similar to those of fuzzy logic operations between individual models, proving fuzzy logic and the favourability function valuable for comparative distribution modelling. We highlight several advantages of fuzzy logic over other forms of combining distribution models, including the possibility to combine multiple species models for management and conservation planning.

  11. Is Huachansu Beneficial in Treating Advanced Non-Small-Cell Lung Cancer? Evidence from a Meta-Analysis of Its Efficacy Combined with Chemotherapy

    Directory of Open Access Journals (Sweden)

    Bingduo Zhou

    2015-01-01

    Full Text Available Background. Huachansu, the sterilized water extract of Bufo bufo gargarizans toad skin, is used in China to alleviate the side-effects and enhance the therapeutic effect of chemotherapy in advanced non-small-cell lung cancer (NSCLC. We conducted a meta-analysis to assess Huachansu’s efficacy. Methods. We extensively searched electronic databases (CENTRAL, EMBASE, MEDLINE, CBM, Cochrane Library, CNKI, CEBM, WFDP, CSCD, CSTD, and IPA for randomized controlled trials containing Huachansu plus chemotherapy as the test group and chemotherapy as the control group. Seventeen trials were selected based on the selection criteria. The pooled relative ratio (RR of indicators with 95% confidence interval (95% CI was calculated for efficacy evaluation. Results. The meta-analysis demonstrated a statistically significant improvement in objective tumor response, one-year survival, Karnofsky performance status, pain relief, and alleviation of severe side-effects (nausea and vomiting, leukocytopenia in the test group as compared to the control group, but no significant difference in thrombocytopenia. Conclusions. This study demonstrated the efficacy of Huachansu combined with chemotherapy in the treatment of advanced NSCLC. However, limitations exist and high-quality trials are needed for further verification.

  12. Juvenile frogs compensate for small metamorph size with terrestrial growth: Overcoming the effects of larval density and insecticide exposure

    Science.gov (United States)

    Boone, M.D.

    2005-01-01

    I reared four species of anurans (Rana sphenocephala [Southern Leopard Frog], Rana blairi [Plains Leopard Frog], Rana clamitans [Green Frog], and Bufo woodhousii [Woodhouse's Toad]) for seven to 12 months in small, outdoor terrestrial enclosures (1 x 2 m) to examine the consequences of larval competition (via density) and contaminant exposure (via the insecticide carbaryl). I added six Rana clamitans, eight Rana sphenocephala, eight Rana blairi, and 10 Bufo woodhousii to terrestrial enclosures shortly after metamorphosis and recaptured them during the following spring. All anurans from low-density ponds were significantly larger than those from high-density ponds, but these size differences did not significantly affect survival to or size at spring emergence. However, R. sphenocephala, R. blairi, and R. clamitans that survived to spring had been larger at metamorphosis on average than those that did not survive; in contrast, B. woodhousii that survived the winter were smaller at metamorphosis on average than those that did not survive. Carbaryl exposure affected mass at metamorphosis of R. clamitans and B. woodhousii that were added to enclosures, but this difference disappeared or did not increase by spring emergence. Overall, exposure to carbaryl during the larval period did not have any apparent effects on survival or growth during the terrestrial phase. In my study, anurans were able to offset small size at metamorphosis with terrestrial growth, although there was a trend of reduced overwinter survival for ranid species that metamorphosed at a smaller size. Copyright 2005 Society for the Study of Amphibians and Reptiles.

  13. Body size affects the predatory interactions between introduced American Bullfrogs (Rana catesbeiana) and native anurans in China: An experimental study

    Science.gov (United States)

    Wang, Y.; Guo, Z.; Pearl, C.A.; Li, Y.

    2007-01-01

    Introduced American Bullfrogs (Rana catesbeiana) have established breeding populations in several provinces in China since their introduction in 1959. Although Bullfrogs are viewed as a potentially important predator of Chinese native anurans, their impacts in the field are difficult to quantify. We used two experiments to examine factors likely to mediate Bullfrog predation on native anurans. First, we examined effects of Bullfrog size and sex on daily consumption of a common Chinese native (Rana limnocharis). Second, we examined whether Bullfrogs consumed similar proportions of four Chinese natives: Black-Spotted Pond Frog (Rana nigromaculata), Green Pond Frog (Rana plancyi plancyi), Rice Frog (R. limnocharis), and Zhoushan Toad (Bufo bufo gargarizans). We found that larger Rana catesbeiana consumed more R. limnocharis per day than did smaller R. catesbeiana, and that daily consumption of R. limnocharis was positively related to R. catesbeiana body size. When provided with adults of four anurans that differed significantly in body size, R. catesbeiana consumed more individuals of the smallest species (R. limnocharis). However, when provided with similarly sized juveniles of the same four species, R. catesbeiana did not consume any species more than expected by chance. Our results suggest that body size plays an important role in the predatory interactions between R. catesbeiana and Chinese native anurans and that, other things being equal, smaller species and individuals are at greater risk of predation by R. catesbeiana. Copyright 2007 Society for the Study of Amphibians and Reptiles.

  14. First detection of circovirus-like sequences in amphibians and novel putative circoviruses in fishes.

    Science.gov (United States)

    Tarján, Zoltán László; Pénzes, Judit J; Tóth, Róza P; Benkő, Mária

    2014-03-01

    The negative samples of a collection, established originally for seeking new adeno- and herpesviruses in lower vertebrates, were screened for the pres-ence of circoviruses by a consensus nested PCR targeting the gene coding for the replication-associated protein. Six fish samples representing five species, namely asp (Aspius aspius), roach (Rutilus rutilus), common bream (Abramis brama), round goby (Neogobius melanostomus) and monkey goby (Neogobius fluviatilis), as well as three frog samples were found positive for circoviral DNA. Sequence analysis of the amplicons indicated the presence of three novel putative circo-like viruses and a circovirus in Hungarian fishes and one novel circovirus in a common toad (Bufo bufo), and another one in a dead and an alive specimen of green tree frog (Litoria caerulea), respectively. In phylogeny reconstruction, the putative bream circovirus clustered together with circoviruses discovered in other cyprinid fishes recently. Three other piscine circoviral sequences appeared closest to sequences derived from different environmental samples. Surprisingly, the nucleotide sequence derived from two fish samples (a bream and a monkey goby) proved to be from porcine circovirus 2 (PCV2), almost identical to a sequence detected in Sweden previously. This is the first report on the detection of PCV2 in fish and circoviral DNA in amphibian hosts. PMID:24334078

  15. Combined exposure to ambient UVB radiation and nitrite negatively affects survival of amphibian early life stages

    Energy Technology Data Exchange (ETDEWEB)

    Macias, Guadalupe [Donana Biological Station, CSIC, Spanish Council for Scientific Research. P.O. Box 1056, Sevilla 41013 (Spain); Marco, Adolfo [Donana Biological Station, CSIC, Spanish Council for Scientific Research. P.O. Box 1056, Sevilla 41013 (Spain)], E-mail: amarco@ebd.csic.es; Blaustein, Andrew R. [Department of Zoology, Oregon State University, Corvallis, Oregon, 97331 (United States)

    2007-10-15

    Many aquatic species are sensitive to ambient levels of ultraviolet-B radiation (UVB) and chemical fertilizers. However, recent studies indicate that the interaction among multiple stressors acting simultaneously could be contributing to the population declines of some animal species. Therefore, we tested the potential synergistic effects between ambient levels of UVB and a contaminant, sodium nitrite in the larvae of two amphibian species, the common European toad Bufo bufo and the Iberian green frog Rana perezi. We studied R. perezi from both mountain and coastal populations to examine if populations of the same species varied in their response to stressors in different habitats. Both species were sensitive to the two stressors acting alone, but the interaction between the two stressors caused a multiplicative impact on tadpole survival. For B. bufo, the combination of UVB and nitrite was up to seven times more lethal than mortality for each stressor alone. In a coastal wetland, the combination of UVB and nitrite was four times more toxic for R. perezi than the sum of the effect on mortality for each stressor alone. One mg/L of nitrite killed half the population of R. perezi at Gredos Mountains at day 10 in the absence of UVB. In the presence of UVB, 50% of the tadpoles from the same experiment died at day 7. Similar toxic response were found for R. perezi in two highly contrasted environments suggesting this synergistic interaction can be a widespread phenomenon. The interaction of excess chemical fertilizers and manure with ambient UVB radiation could be contributing to the global decline of some amphibian species. We suggest that potential exposure to UVB radiation be accounted for when assessing water quality criteria regarding nitrite pollution.

  16. Comparative ultrastructural analysis of two tortoise bladders, Testudo graeca and Geochelone carbonaria.

    Science.gov (United States)

    Strum, J M; Danon, D

    1976-01-01

    Urinary bladders from the desert tortoises, Testudo graeca and Geochelone carbonaria were removed at specific times during the year and species in all bladders examined: (1) granular cells, (2) mitochondria-rich cells, and (3) basal cells. Cells analogous to these three types have also been observed in amphibian bladders (from toad Bufo marinus and bullfrog, Rana catesbiana) and reptilian bladders (from Pseudemys scripta and Clemmys caspica). Both tortoises have an incomplete layer of basal cells so that the granular and mitochondria-rich cells extend from the lumen to the basement membrane: something was not observed in bladders from bullfrog or turtles. A flask-shaped light cell was observed in the Geochelone carbonaria bladder obtained in April. No counterpart of this cell was seen in the same species sacrificed in January, or in any of the Testudo graeca bladders, although a similar cell has been described in the turtle, Pseudemys scripta (Rosen, Expt. Molec. Path., 12: 286-296, '70). This study was undertaken to characterize the cell types present in tortoise bladder and to compare them with cell types in the bladder of the turtle, bullfrog and toad. PMID:1252017

  17. Amphibian breeding and climate change: The importance of snow in the mountains

    Science.gov (United States)

    Corn, P. Stephen

    2003-01-01

    The breeding phenologies of ectotherms are inextricably linked to weather, and amphibians in some temperate locations may have been breeding earlier in recent years in response to warmer spring temperatures (Beebee 1995: Forchhammer et al. 1998; Gibbs & Breisch 2001). Directional change in the timing of breeding resulting from climate change may have consequences for the fitness of individuals and may affect the persistence of amphibian populations (Ovaska 1997: Donnelly & Crump 1998). Blaustein et al. (2001) contribute valuable information to the small, but growing, data set of long-term observations of amphibian breeding phenology. As in other studies, Blaustein et al. found a significant relationship between air temperature and phenology, with earlier breeding associated with warmer air temperatures for boreal toads (Bufo boreas) and Cascades frogs (Rana cascadae) in Oregon and for spring peepers (Pseudacris crucifer) in Michigan. Contrary to other studies, however, there was no trend toward earlier breeding relative to year for any of these species or for Fowler's toads (B. fouleri) in Ontario. These results are important in demonstrating that changes in breeding phenology due to climate change are not universal among amphibians.

  18. Biological response to climate change on a tropical mountain

    Science.gov (United States)

    Pounds, J. Alan; Fogden, Michael P. L.; Campbell, John H.

    1999-04-01

    Recent warming has caused changes in species distribution and abundance, but the extent of the effects is unclear. Here we investigate whether such changes in highland forests at Monteverde, Costa Rica, are related to the increase in air temperatures that followed a step-like warming of tropical oceans in 1976 (refs4, 5). Twenty of 50 species of anurans (frogs and toads) in a 30-km2 study area, including the locally endemic golden toad (Bufo periglenes), disappeared following synchronous population crashes in 1987 (refs 6-8). Our results indicate that these crashes probably belong to a constellation of demographic changes that have altered communities of birds, reptiles and amphibians in the area and are linked to recent warming. The changes are all associated with patterns of dry-season mist frequency, which is negatively correlated with sea surface temperatures in the equatorial Pacific and has declined dramatically since the mid-1970s. The biological and climatic patterns suggest that atmospheric warming has raised the average altitude at the base of the orographic cloud bank, as predicted by the lifting-cloud-base hypothesis,.

  19. Potential component Allee effects and their impact on wetland management in the conservation of endangered anurans.

    Directory of Open Access Journals (Sweden)

    Michele A Gaston

    Full Text Available Effective management of wetland quantity and quality is crucial for effective conservation of declining amphibian populations. In particular, frogs and toads that employ aggregative breeding strategies may suffer negative population impacts in response to changes in availability of aquatic breeding habitat, including overabundance of suitable habitat, if density of conspecifics attending aggregations is positively correlated with reproductive success. Here we document such a positive relationship, potentially the first example of a component Allee effect in an anuran, in the critically endangered Houston toad (Bufo houstonensis. We assessed the relationship between mean yearly chorus size and reproductive success of males at the pond level using an information theoretic model selection approach and a two-sample t-test. The chosen model contained the single variable of mean yearly chorus size to predict probability of reproduction, as selected using the Akaike Information Criterion corrected for small sample size and Akaike weight. Mean chorus sizes were significantly higher among ponds exhibiting evidence of reproduction than in those that showed no evidence of reproduction. Our results suggest that chorusing alone is a poor proxy for inference of population stability and highlight a need for reassessment of widely-used amphibian monitoring protocols. Further, amphibian conservation efforts should account for potential Allee effects in order to optimize benefits and avoid underestimating critical population thresholds, particularly in species exhibiting rapid population declines.

  20. Multiple stressors in amphibian communities: Effects of chemical contamination, bullfrogs, and fish

    Science.gov (United States)

    Boone, M.D.; Semlitsch, R.D.; Little, E.E.; Doyle, M.C.

    2007-01-01

    A leading hypothesis of amphibian population declines is that combinations of multiple stressors contribute to declines. We examined the role that chemical contamination, competition, and predation play singly and in combination in aquatic amphibian communities. We exposed larvae of American toads (Bufo americanus), southern leopard frogs (Rana sphenocephala), and spotted salamanders (Ambystoma maculatum) to overwintered bullfrog tadpoles (R. catesbeiana), bluegill sunfish (Lepomis macrochirus), the insecticide carbaryl, and ammonium nitrate fertilizer in 1000-L mesocosms. Most significantly, our study demonstrated that the presence of multiple factors reduced survival of B. americanus and A. maculatum and lengthened larval periods of R. sphenocephala. The presence of bluegill had the largest impact on the community; it eliminated B. americanus and A. maculatum and reduced the abundance of R. sphenocephala. Chemical contaminants had the second strongest effect on the community with the insecticide, reducing A. maculatum abundance by 50% and increasing the mass of anurans (frogs and toads) at metamorphosis; the fertilizer positively influenced time and mass at metamorphosis for both anurans and A. maculatum. Presence of overwintered bullfrogs reduced mass and increased time to metamorphosis of anurans. While both bluegill and overwintered bullfrog tadpoles had negative effects on the amphibian community, they performed better in the presence of one another and in contaminated habitats. Our results indicate that predicting deleterious combinations from single-factor effects may not be straightforward. Our research supports the hypothesis that combinations of factors can negatively impact some amphibian species and could contribute to population declines. ?? 2007 by the Ecological Society of America.

  1. Toxicity of road salt to Nova Scotia amphibians

    International Nuclear Information System (INIS)

    The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC50) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species. - Salt toxicity is presented as a mechanism affecting the distribution of amphibians and structure of amphibian communities in roadside wetlands

  2. The uranium content in the blood of some vertebrates

    International Nuclear Information System (INIS)

    The method of fission track analysis has been used to estimate the uranium concentration in the blood of some vertebrates like lata fish (Ophiocephalus punctatus - class Pisces), toad (Bufo melanostictus -class Amphibia) and man (Homo Sapiens - class Mammalia). The uranium content in the blood of these vertebrates has been found to range from 0.20 ± 0.016 to 0.94 ± 0.038 microgram/litre. However, the concentration in toad is found to be the lowest (0.20 ± 0.016 to 0.40 ± 0.022 microgram/litre) as compared to that in fish (0.50 ± 0.027 to 0.94 ± 0.038 microgram/litre) and man (0.33 ± 0.023 to 0.74 ± 0.034 microgram/litre). The intervariation among the different classes of vertebrates as regards uranium concentration has been found to be statistically significant. (author)

  3. Influenza em animais heterotérmicos Influenza in heterothermics

    Directory of Open Access Journals (Sweden)

    Dalva Assunção Portari Mancini

    2004-06-01

    Full Text Available O objetivo foi pesquisar Ortomyxovirus em animais heterotérmicos. Coletou-se sangue de serpentes dos gêneros Bothrops e Crotalus e de sapo e rãs dos gêneros Bufo e Rana, para a detecção dos receptores de hemácias e anticorpos específicos, ao vírus influenza, pelos testes de hemaglutinação e inibição da hemaglutinação, respectivamente. Pelo teste de hemaglutinação, verificou-se que serpentes e sapos em cativeiro apresentaram receptores em suas hemácias para o vírus influenza, humano e eqüino do tipo A e tipo B. O mesmo ocorreu com serpentes recém chegadas. Quanto ao teste de inibição da hemaglutinação dos soros dos répteis observou-se títulos protetores de anticorpos aos vírus influenza tipo A (origens humana e eqüina e tipo B. Com soro de sapo não se observou reação de inibição da hemaglutinação porém, 83,3% das rãs obtiveram médias de 40UIH para algumas cepas. Conclui-se que animais heterotérmicos podem oferecer condições de hospedeiros aos vírus influenza, assim como susceptibilidade à infecção.The objective was to study Orthomyxovirus in heterothermic animals. Blood samples from snakes (genus Bothrops and Crotalus and from toads and frogs (genus Bufo and Rana were collected to evaluate the red cell receptors and antibodies specific to influenza virus by the hemagglutination and hemagglutination inhibition tests, respectively. Both snakes and toads kept in captivity presented receptors in their red cells and antibodies specific to either influenza virus type A (human and equine origin or influenza type B. The same was observed with recently captured snakes. Concerning the influenza hemagglutination inhibition antibodies protective levels were observed in the reptiles' serum, against influenza type A and type B. Unlike the toads, 83.3% of the frogs presented mean levels of Ab 40HIU for some influenza strains. It was concluded that heterothermic animals could offer host conditions to the influenza

  4. CITIZEN SCIENTISTS MONITOR A DEADLY FUNGUS THREATENING AMPHIBIAN COMMUNITIES IN NORTHERN COASTAL CALIFORNIA, USA.

    Science.gov (United States)

    Group, Ecoclub Amphibian; Pope, Karen L; Wengert, Greta M; Foley, Janet E; Ashton, Donald T; Botzler, Richard G

    2016-07-01

    Ecoclub youth and supervising family members conducted citizen science to assess regional prevalence and distribution of Batrachochytrium dendrobatidis (Bd) among amphibians at Humboldt Bay National Wildlife Refuge (Refuge) and Redwood National and State Parks (Parks), Humboldt County, California, US, May 2013 through December 2014. Using quantitative real-time PCR, 26 (17%) of 155 samples were positive for Bd. Positive samples occurred in four frog and toad species: foothill yellow-legged frog ( Rana boylii ), northern red-legged frog ( Rana aurora ), Pacific chorus frog ( Pseudacris regilla ), and western toad (Anaxyrus [Bufo] boreas); no salamanders or anuran larvae were positive. Except for R. aurora , all infected anurans were first-time species reports for coastal northern California. At the Refuge, significantly fewer (6/71) postmetamorphic amphibians were positive compared to the Parks (20/69; P=0.0018). We assessed the association of being PCR-positive for Bd, season of sampling, and age of sampler (child, teen, or adult). The full model with season, species, and sampler age had the greatest support. Frogs tested in winter or spring were more likely to be positive than those tested in summer or fall; foothill yellow-legged frogs, northern red-legged frogs, and western toads were more likely to be positive than were Pacific chorus frogs; and the probability of being positive nearly doubled when a child (≤12 yr old) collected the sample compared to a teen or adult. Our results support other chytrid studies that found amphibians are more susceptible to Bd when temperatures are cool and that species differ in their susceptibility. The Ecoclub's findings provide new information important to conservation of northern California's coastal amphibians and demonstrate the value of involving children in citizen science. PMID:27195681

  5. Interactions of an insecticide with competition and pond drying in amphibian communities

    Science.gov (United States)

    Boone, M.D.; Semlitsch, R.D.

    2002-01-01

    Amphibian populations are often imbedded in agricultural landscapes. Therefore the potential for contamination of their habitat is considerable. Our study examined the effects of an insecticide (carbaryl, a neurotoxin), on larval amphibian communities experiencing natural stresses of competition for resources, predation, and pond drying. In a set of experimental ponds, tadpoles of three anuran species (southern leopard frog [Rana sphenocephala], plains leopard frog [R. blairi], and the Woodhouse's toad [Bufo woodhousii]) were added to 1000-L ponds containing leaf litter, plankton, two newts (Notophthalmus viridescens), and four overwintered green frog (R. clamitans) tadpoles. We manipulated the overall tadpole density (low or high), pond hydroperiod (constant or drying), and chemical exposure (0, 3.5, 5.0, or 7.0 mg/L carbaryl) of the ponds. We measured mass, time, and survival to metamorphosis to determine treatment effects. Carbaryl positively affected Woodhouse's toad survival, although it had a negligible effect on both leopard frog species. Tadpole density interacted with the chemical treatment: Proportionately more Woodhouse's toads survived to metamorphosis in high-density environments than in low-density or control environments. Greater survival may be an indirect effect of increased algal food resources from carbaryl exposure. Most newts lost mass over the course of the experiment, although ponds with drying hydroperiods and high anuran density were the least favorable environments. Overwintered green frogs exposed to carbaryl had longer larval periods on average than did green frogs in control ponds. Our study demonstrated that even sublethal, short-lived contaminants can alter natural communities in ways that cannot be predicted from simple, one-factor studies.

  6. Distribution and environmental limitations of an amphibian pathogen in the Rocky Mountains, USA

    Science.gov (United States)

    Muths, E.; Pilliod, D.S.; Livo, L.J.

    2008-01-01

    Amphibian populations continue to be imperiled by the chytrid fungus (Batrachochytrium dendrobatidis). Understanding where B. dendrobatidis (Bd) occurs and how it may be limited by environmental factors is critical to our ability to effectively conserve the amphibians affected by Bd. We sampled 1247 amphibians (boreal toads and surrogates) at 261 boreal toad (Bufo boreas) breeding sites (97 clusters) along an 11?? latitudinal gradient in the Rocky Mountains to determine the distribution of B. dendrobatidis and examine environmental factors, such as temperature and elevation, that might affect its distribution. The fungus was detected at 64% of all clusters and occurred across a range of elevations (1030-3550 m) and latitudes (37.6-48.6??) but we detected it in only 42% of clusters in the south (site elevations higher), compared to 84% of clusters in the north (site elevations lower). Maximum ambient temperature (daily high) explained much of the variation in Bd occurrence in boreal toad populations and thus perhaps limits the occurrence of the pathogen in the Rocky Mountains to areas where climatic conditions facilitate optimal growth of the fungus. This information has implications in global climate change scenarios where warming temperatures may facilitate the spread of disease into previously un- or little-affected areas (i.e., higher elevations). This study provides the first regional-level, field-based effort to examine the relationship of environmental and geographic factors to the distribution of B. dendrobatidis in North America and will assist managers to focus on at-risk populations as determined by the local temperature regimes, latitude and elevation.

  7. ROLE OF THE EGG JELLY COAT IN PROTECTING HYLA REGILLA AND BUFO CANORUS EMBRYOS FROM ULTRAVIOLET B RADIATION DURING DEVELOPMENT

    Science.gov (United States)

    Previous studies have suggested that Ultraviolet B (UVB) radiation may play a role in amphibian population declines. Some of these studies also indicate that egg hatching success is unaltered in some species of anurans as a result of UVB exposure. It has been proposed that the eg...

  8. Keystone predators (eastern newts, Notophthalmus viridescens) reduce the impacts of an aquatic invasive species

    Science.gov (United States)

    Smith, Kimberly G.

    2006-01-01

    Predation, competition, and their interaction are known to be important factors that influence the structure of ecological communities. In particular, in those cases where a competitive hierarchy exists among prey species, the presence of certain keystone predators can result in enhanced diversity in the prey community. However, little is known regarding the influence of keystone predator presence on invaded prey communities. Given the widespread occurrence of invasive species and substantial concern regarding their ecological impacts, studies on this topic are needed. In this study I used naturalistic replications of an experimental tadpole assemblage to assess the influence of predatory eastern newts, Notophthalmus viridescens, on the outcome of interspecific competition among native and nonindigenous tadpoles. When newts were absent, the presence of the tadpoles of one invasive species, the Cuban treefrog, Osteopilus septentrionalis, resulted in decreased survival and growth rate of the dominant native species, Bufo terrestris, and dominance of the tadpole assemblage by O. septentrionalis. However, the presence of one adult newt generally reduced or eliminated the negative impacts of O. septentrionalis tadpoles, resulting in comparable survival and performance of native species in invaded and noninvaded treatments. Differential mortality among the tadpole species suggests that newts preyed selectively on O. septentrionalis tadpoles, supporting the hypothesis that newts acted as keystone predators in the invaded assemblage. The presence of nonindigenous larval cane toads, Bufo marinus, did not significantly affect native species, and this species was not negatively affected by the presence of newts. Collectively, these results suggest that eastern newts significantly modified the competitive hierarchy of the invaded tadpole assemblage and reduced the impacts of a competitively superior invasive species. If general, these results suggest that the presence of

  9. Enthalpic consequences of reduced chloride binding in Andean frog (Telmatobius peruvianus) hemoglobin.

    Science.gov (United States)

    Weber, Roy E

    2014-07-01

    Based on the exothermic nature of heme oxygenation, the O2 affinity of hemoglobin (Hb) decreases with increasing temperature, which may be physiologically advantageous in augmenting O2 unloading from blood in warm tissues with elevated metabolic rates. This negative oxygenation enthalpy (∆H (O)) may, however, become maladaptive, as in cold-tolerant ungulates where it may hamper O2 unloading in cold extremities and commonly is mitigated by an 'additional' chloride-binding site that decreases the temperature effect by increasing the endothermic release of Cl(-) ions upon O2 binding. Since no previous studies have focused on the consequences of reduced Cl(-) binding, I report and compare the enthalpic effects of chloride ions and the allosteric effector, ATP, on Hbs of the high-altitude aquatic Andean frog Telmatobius peruvianus that lacks the α-chain chloride-binding site, and the lowland (sub-)tropical frog Xenopus laevis that has retained this site and exhibits high chloride sensitivity. In contrast to Xenopus, Telmatobius Hb exhibits high temperature sensitivity (high negative ∆H') in the presence of Cl(-) ions, supporting the inverse relationship between the number of Cl(-)-binding sites and temperature sensitivity, and extending it to ectothermic vertebrates. The radically reduced chloride binding in Telmatobius Hb permits assessment of the enthalpy of ATP binding [(∆H' ≈ -62 kJ (mol ATP)(-1) at pH 7.0]-which contrasts sharply with previously reported increases in temperature sensitivity by ATP in toad (Bufo bufo) Hb. The high temperature sensitivity associated with decreased chloride binding and low phosphate sensitivity of Telmatobius Hb likely promotes cutaneous O2 uptake in cold, high-altitude ponds and streams.

  10. Membrane potential plays a dual role for chloride transport across toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Rasmussen, B E

    1983-01-01

    -dependent currents are not caused by a trivial Goldmand-type rectification and ion redistributions following transepithelial potential pertubations. Extended with a dynamic Cl- permeability in the apical membrane according to a Hodgkin-Huxley kinetic scheme, the model predicts voltage clamp data which closely...

  11. Watch Out for the Under Toad : Role and Method of Interdisciplinary Contextualisation in Comparative Legal Research

    NARCIS (Netherlands)

    E. Mak (Elaine)

    2015-01-01

    textabstractThis article studies the significance of insights from non- legal disciplines (such as political science, economics, and sociology) for comparative legal research and the methodology connected with such ‘interdisciplinary contextualisation’. Based on a theoretical analysis concerning the

  12. NHE-1 sequence and expression in toad, snake and fish red blood cells

    DEFF Research Database (Denmark)

    Thomsen, Steffen Nyegaard; Wang, Tobias; Kristensen, Torsten

    Red blood cells (RBC) from reptiles appear not to express regulatory volume increase (RVI) upon shrinkage (Kristensen et al., 2008). In other vertebrates, the RVI response is primarily mediated by activation of the Na+/H+ exchanger (NHE-1) and we, therefore decided to investigate whether red cell...

  13. Use of oxytetracycline in batch-marking post-metamorphic boreal toads

    Science.gov (United States)

    Muths, E.; Corn, P.S.; Stanley, T.R.

    2000-01-01

    Comparison of organochlorine residues in wildlife must often be made to regulatory standards or to values of known biological significance; this is difficult when dissimilar tissues are analyzed and results are expressed on different bases. To relate levels in the different tissues used for regulatory and monitoring purposes and for biological assessments, we exposed American black ducks to mixtures of three organochlorines. Differences in residue burdens among tissues were not statistically significant when levels were expressed on a lipid weight basis. Levels of heptachlor and Aroclor 1254 in one tissue can be accurately predicted from those in another; such predictions for endrin are less reliable. Lipid weight based residue concentrations in wings may be used to predict whether levels in fat exceed residue standards set for human health or approach those associated with effects on populations of species sampled.

  14. Cane Toad or Computer Mouse? Real and Computer-Simulated Laboratory Exercises in Physiology Classes

    Science.gov (United States)

    West, Jan; Veenstra, Anneke

    2012-01-01

    Traditional practical classes in many countries are being rationalised to reduce costs. The challenge for university educators is to provide students with the opportunity to reinforce theoretical concepts by running something other than a traditional practical program. One alternative is to replace wet labs with comparable computer simulations.…

  15. Amiloride inhibits mammalian renal kallikrein and a kallikrein-like enzyme from toad bladder and skin.

    OpenAIRE

    Margolius, H S; Chao, J.

    1980-01-01

    Renal kallikrein is localized in luminal plasma membranes of the mammalian distal nephron and gains access to urine from this site. Its activity is regulated, in part, by aldosterone. These facts led us to study the effects of amiloride, a drug known to inhibit sodium reabsorption and potassium secretion at this site, on kallikrein activity. Amiloride inhibited the esterolytic activity of purified rat or human urinary kallikrein or of rat renal cortical cells upon a synthetic substrate (ID50 ...

  16. 75 FR 37358 - Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for the Arroyo Toad

    Science.gov (United States)

    2010-06-29

    ... 7 percent discount rate. Overall, the real estate industry (real estate development, CEQA, and delay... present value terms using a 7 percent discount rate. Overall, the real estate industry (real estate... following categories: (1) Real estate development; (2) changes in water supply; (3) grazing activities;......

  17. Adverse effect of agroecosystem pond water on biological endpoints of common toad (Rhinella arenarum) tadpoles.

    Science.gov (United States)

    Babini, María Selene; Bionda, Clarisa de Lourdes; Salas, Nancy Edith; Martino, Adolfo Ludovico

    2016-08-01

    Chemical prroducts used in farming and wastes from livestock can contaminate pond water in agroecosystems due to runoff. Amphibians using these ponds for breeding are probably exposed to pollutants, and serious consequences might be observed afterward at the population level. Assessment biological endpoints of anuran to water quality give a realistic estimate of the probability of occurrence of adverse effects and provide an early warning signal. In this study, the ecotoxicity of agroecosystem ponds from the south of Córdoba province, Argentina, was investigated. Ponds in four sites with different degrees of human disturbance were selected: three agroecosystems (A1, A2, A3) and a site without crops or livestock (SM). The effect of pond water quality on the biological endpoint of Rhinella arenarum tadpoles was examined using microcosms with pond water from sites. Biological endpoints assessed were as follows: mortality, growth, development, morphological abnormalities (in body shape, gut, and labial tooth row formula), behavior, and blood cell parameters (micronucleus and nuclear abnormalities). Results indicated that water from agroecosystems has adverse effect on early life stage of R. arenarum. High mortality and fewer metamorphs were recorded in the A1 and A3 treatments. Tadpoles and metamorphs from A1 and A2 treatments had lower body condition. Tadpoles from A1 and A3 showed the highest prevalence of morphological abnormalities. The lowest amount of tadpoles feeding and the highest percentage of tadpoles swimming on the surface were observed in treatments with agroecosystem pond water. The higher frequencies of micronuclei and nuclear abnormalities were recorded in tadpoles from A1, A2, and A3 treatments. We check the sensitivity of the biological endpoints of R. arenarum tadpoles like early warning indicators of water quality. We found that the poor water quality of agroecosystem ponds has impact on the health of the tadpoles, and this could affect the persistence of populations. We recommend implementation of management actions before the harmful effects of agroecosystem pond water on early life stage of anuran become evident in higher ecological levels. PMID:27395360

  18. A new species of arboreal toad (Anura : Bufonidae : Chaunus) from Madidi National Park, Bolivia

    Science.gov (United States)

    Padial, J.M.; Reichle, S.; McDiarmid, R.; De la Riva, I.

    2006-01-01

    A new arboreal species of the Chaunus veraguensis group is described for the humid montane forest of Madidi National Park, in northern Bolivia. The new species differs from other species in the group by the combination small size, long and slender extremities, webbed hands, conspicuous tympanic membrane, well developed parotoid glands, absence of large glands on dorsum and extremities, nuptial excrescences of males composed of pungent spines on dorsal surface of thumb, greenish-brown coloration on dorsum with red warts in life, and green iris. It is only known from two nearby localities in the Serran Eslabon, Department La Paz. An operational key for species in the C. veraguensis group is provided.

  19. Integrating Multiple Distribution Models to Guide Conservation Efforts of an Endangered Toad

    OpenAIRE

    Treglia, Michael L.; Fisher, Robert N.; Fitzgerald, Lee A.

    2015-01-01

    Species distribution models are used for numerous purposes such as predicting changes in species' ranges and identifying biodiversity hotspots. Although implications of distribution models for conservation are often implicit, few studies use these tools explicitly to inform conservation efforts. Herein, we illustrate how multiple distribution models developed using distinct sets of environmental variables can be integrated to aid in identification sites for use in conservation. We focus on th...

  20. The relative impacts of native and introduced predatory fish on a temporary wetland tadpole assemblage.

    Science.gov (United States)

    Baber, Matthew J; Babbitt, Kimberly J

    2003-07-01

    Understanding the relative impacts of predators on prey may improve the ability to predict the effects of predator composition changes on prey assemblages. We experimentally examined the relative impact of native and introduced predatory fish on a temporary wetland amphibian assemblage to determine whether these predators exert distinct (unique or non-substitutable) or equivalent (similar) impacts on prey. Predatory fish included the eastern mosquitofish (Gambusia holbrooki), golden topminnow (Fundulus chrysotus), flagfish ( Jordanella floridae), and the introduced walking catfish ( Clarias batrachus). The tadpole assemblage included four common species known to co-occur in temporary wetlands in south-central Florida, USA: the oak toad (Bufo quercicus), pinewoods treefrog (Hyla femoralis), squirrel treefrog (Hyla squirella), and eastern narrowmouth toad (Gastrophryne carolinensis). Tadpoles were exposed to different predators in wading pools under conditions similar to those found in surrounding temporary wetlands (particularly in terms of substrate type, the degree of habitat complexity, and temperature). Native predators were similar with respect to predation rate and prey selectivity, suggesting similar energy requirements and foraging behavior. Conversely, native fish predators, especially G. holbrooki, were distinct from the introduced C. batrachus. In contrast to expectations, C. batrachus were less voracious predators than native fish, particularly G. holbrooki. Moreover, survival of G. carolinensis and H. femoralis were higher in the presence of C. batrachus than G. holbrooki. We suggest that C. batrachus was a less efficient predator than native fish because the foraging behavior of this species resulted in low predator-prey encounter rates, and thus predation rate. In combination with a related field study, our results suggest that native predatory fish play a stronger role than C. batrachus in influencing the spatial distribution and abundance of

  1. Cladistic analysis of anuran POMC sequences.

    Science.gov (United States)

    Alrubaian, Jasem; Danielson, Phillip; Walker, David; Dores, Robert M

    2002-03-01

    Procedures for performing cladistic analyses can provide powerful tools for understanding the evolution of neuropeptide and polypeptide hormone coding genes. These analyses can be done on either amino acid data sets or nucleotide data sets and can utilize several different algorithms that are dependent on distinct sets of operating assumptions and constraints. In some cases, the results of these analyses can be used to gauge phylogenetic relationships between taxa. Selecting the proper cladistic analysis strategy is dependent on the taxonomic level of analysis and the rate of evolution within the orthologous genes being evaluated. For example, previous studies have shown that the amino acid sequence of proopiomelanocortin (POMC), the common precursor for the melanocortins and beta-endorphin, can be used to resolve phylogenetic relationships at the class and order level. This study tested the hypothesis that POMC sequences could be used to resolve phylogenetic relationships at the family taxonomic level. Cladistic analyses were performed on amphibian POMC sequences characterized from the marine toad, Bufo marinus (family Bufonidae; this study), the spadefoot toad, Spea multiplicatus (family Pelobatidae), the African clawed frog, Xenopus laevis (family Pipidae) and the laughing frog, Rana ridibunda (family Ranidae). In these analyses the sequence of Australian lungfish POMC was used as the outgroup. The analyses were done at the amino acid level using the maximum parsimony algorithm and at the nucleotide level using the maximum likelihood algorithm. For the anuran POMC genes, analysis at the nucleotide level using the maximum likelihood algorithm generated a cladogram with higher bootstrap values than the maximum parsimony analysis of the POMC amino acid data set. For anuran POMC sequences, analysis of nucleotide sequences using the maximum likelihood algorithm would appear to be the preferred strategy for resolving phylogenetic relationships at the family taxonomic

  2. Expression of G proteins in the olfactory receptor neurons of the newt Cynops pyrrhogaster: their unique projection into the olfactory bulbs.

    Science.gov (United States)

    Nakada, Tomoaki; Hagino-Yamagishi, Kimiko; Nakanishi, Koki; Yokosuka, Makoto; Saito, Toru R; Toyoda, Fumiyo; Hasunuma, Itaru; Nakakura, Takashi; Kikuyama, Sakae

    2014-10-15

    We analyzed the expression of G protein α subunits and the axonal projection into the brain in the olfactory system of the semiaquatic newt Cynops pyrrhogaster by immunostaining with antibodies against Gαolf and Gαo , by in situ hybridization using probes for Gαolf , Gαo , and Gαi2 , and by neuronal tracing with DiI and DiA. The main olfactory epithelium (OE) consists of two parts, the ventral OE and dorsal OE. In the ventral OE, the Gαolf - and Gαo -expressing neurons are located in the apical and basal zone of the OE, respectively. This zonal expression was similar to that of the OE in the middle cavity of the fully aquatic toad Xenopus laevis. However, the Gαolf - and Gαo -expressing neurons in the newt ventral OE project their axons toward the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB), respectively, whereas in Xenopus, the axons of both neurons project solely toward the MOB. In the dorsal OE of the newt, as in the principal cavity of Xenopus, the majority of the neurons express Gαolf and extend their axons into the MOB. In the vomeronasal organ (VNO), the neurons mostly express Gαo . These neurons and quite a few Gαolf -expressing neurons project their axons toward the AOB. This feature is similar to that in the terrestrial toad Bufo japonicus and is different from that in Xenopus, in which VNO neurons express solely Gαo , although their axons invariably project toward the AOB. We discuss the findings in the light of diversification and evolution of the vertebrate olfactory system. PMID:24771457

  3. How might you compare mitochondria from different tissues and different species?

    Science.gov (United States)

    Hulbert, A J; Turner, Nigel; Hinde, Jack; Else, Paul; Guderley, Helga

    2006-02-01

    Mitochondria were isolated from the liver, kidney and mixed hindlimb skeletal muscle of three vertebrate species; the laboratory rat Rattus norvegicus, the bearded dragon lizard Pogona vitticeps, and the cane toad Bufo marinus. These vertebrate species are approximately the same body mass and have similar body temperatures. The content of cytochromes B, C, C1, and A were measured in these isolated mitochondria by oxidised-reduced difference spectra. Adenine nucleotide translocase (ANT) was measured by titration of mitochondrial respiration with carboxyactractyloside and the protein and phospholipid content of isolated mitochondria were also measured. Fatty acid composition of mitochondrial phospholipids was measured. Mitochondrial respiration was measured at 37 degrees C under states III and IV conditions as well as during oligomycin inhibition. Species differed in the ratios of different mitochondrial cytochromes. Muscle mitochondria differed from kidney and liver mitochondria by having a higher ANT content relative to cytochrome content. Respiration rates were compared relative to a number of denominators and found to be most variable when expressed relative to mitochondrial protein content and least variable when expressed relative to mitochondrial cytochrome A and ANT content. The turnover of cytochromes was calculated and found to vary between 1 and 94 electrons s(-1). The molecular activity of mitochondrial cytochromes was found to be significantly positively correlated with the relative polyunsaturation of mitochondrial membrane lipids. PMID:16408229

  4. Predator interference effects on biological control: The "paradox" of the generalist predator revisited

    Science.gov (United States)

    Parshad, Rana D.; Bhowmick, Suman; Quansah, Emmanuel; Basheer, Aladeen; Upadhyay, Ranjit Kumar

    2016-10-01

    An interesting conundrum in biological control questions the efficiency of generalist predators as biological control agents. Theory suggests, generalist predators are poor agents for biological control, primarily due to mutual interference. However field evidence shows they are actually quite effective in regulating pest densities. In this work we provide a plausible answer to this paradox. We analyze a three species model, where a generalist top predator is introduced into an ecosystem as a biological control, to check the population of a middle predator, that in turn is depredating on a prey species. We show that the inclusion of predator interference alone, can cause the solution of the top predator equation to blow-up in finite time, while there is global existence in the no interference case. This result shows that interference could actually cause a population explosion of the top predator, enabling it to control the target species, thus corroborating recent field evidence. Our results might also partially explain the population explosion of certain species, introduced originally for biological control purposes, such as the cane toad (Bufo marinus) in Australia, which now functions as a generalist top predator. We also show both Turing instability and spatio-temporal chaos in the model. Lastly we investigate time delay effects.

  5. Amphibians at risk? Susceptibility of terrestrial amphibian life stages to pesticides.

    Science.gov (United States)

    Brühl, Carsten A; Pieper, Silvia; Weber, Brigitte

    2011-11-01

    Current pesticide risk assessment does not specifically consider amphibians. Amphibians in the aquatic environment (aquatic life stages or postmetamorphic aquatic amphibians) and terrestrial living juvenile or adult amphibians are assumed to be covered by the risk assessment for aquatic invertebrates and fish, or mammals and birds, respectively. This procedure has been evaluated as being sufficiently protective regarding the acute risk posed by a number of pesticides to aquatic amphibian life stages (eggs, larvae). However, it is unknown whether the exposure and sensitivity of terrestrial living amphibians are comparable to mammalian and avian exposure and sensitivity. We reviewed the literature on dermal pesticide absorption and toxicity studies for terrestrial life stages of amphibians, focusing on the dermal exposure pathway, that is, through treated soil or direct overspray. In vitro studies demonstrated that cutaneous absorption of chemicals is significant and that chemical percutaneous passage, P (cm/h), is higher in amphibians than in mammals. In vivo, the rapid and substantial uptake of the herbicide atrazine from treated soil by toads (Bufo americanus) has been described. Severe toxic effects on various amphibian species have been reported for field-relevant application rates of different pesticides. In general, exposure and toxicity studies for terrestrial amphibian life stages are scarce, and the reported data indicate the need for further research, especially in light of the global amphibian decline.

  6. Invasive species management and research using GIS

    Science.gov (United States)

    Holcombe, Tracy R.; Stohlgren, Thomas J.; Jarnevich, Catherine S.

    2007-01-01

    Geographical Information Systems (GIS) are powerful tools in the field of invasive species management. GIS can be used to create potential distribution maps for all manner of taxa, including plants, animals, and diseases. GIS also performs well in the early detection and rapid assessment of invasive species. Here, we used GIS applications to investigate species richness and invasion patterns in fish in the United States (US) at the 6-digit Hydrologic Unit Code (HUC) level. We also created maps of potential spread of the cane toad (Bufo marinus) in the southeastern US at the 8-digit HUC level using regression and environmental envelope techniques. Equipped with this potential map, resource managers can target their field surveys to areas most vulnerable to invasion. Advances in GIS technology, maps, data, and many of these techniques can be found on websites such as the National Institute of Invasive Species Science (www.NIISS.org). Such websites provide a forum for data sharing and analysis that is an invaluable service to the invasive species community.

  7. The effects of ultraviolet-B radiation on the toxicity of fire-fighting chemicals

    Science.gov (United States)

    Calfee, R.D.; Little, E.E.

    2003-01-01

    The interactive effects of ultraviolet (UV) and fire-retardant chemicals were evaluated by exposing rainbow trout (Oncorhyncus mykiss) juveniles and tadpoles of southern leopard frogs (Rana sphenocephala) to six fire-retardant formulations with and without sodium ferrocyanide (yellow prussiate of soda [YPS]) and to YPS alone under three simulated UV light treatments. Yellow prussiate of soda is used as a corrosion inhibitor in some of the fire-retardant chemical formulations. The underwater UV intensities measured were about 2 to 10% of surface irradiance measured in various aquatic habitats and were within tolerance limits for the species tested. Mortality of trout and tadpoles exposed to Fire-Trol?? GTS-R, Fire-Trol 300-F, Fire-Trol LCA-R, and Fire-Trol LCA-F was significantly increased in the presence of UV radiation when YPS was present in the formulation. The boreal toad (Bufo boreas), listed as endangered by the state of Colorado (USA), and southern leopard frog were similar in their sensitivity to these chemicals. Photoenhancement of fire-retardant chemicals can occur in a range of aquatic habitats and may be of concern even when optical clarity of water is low; however, other habitat characteristics can also reduce fire retardant toxicity.

  8. Acute toxicity of zinc to several aquatic species native to the Rocky Mountains.

    Science.gov (United States)

    Brinkman, Stephen F; Johnston, Walter D

    2012-02-01

    National water-quality criteria for the protection of aquatic life are based on toxicity tests, often using organisms that are easy to culture in the laboratory. Species native to the Rocky Mountains are poorly represented in data sets used to derive national water-quality criteria. To provide additional data on the toxicity of zinc, several laboratory acute-toxicity tests were conducted with a diverse assortment of fish, benthic invertebrates, and an amphibian native to the Rocky Mountains. Tests with fish were conducted using three subspecies of cutthroat trout (Colorado River cutthroat trout Oncorhynchus clarkii pleuriticus, greenback cutthroat trout O. clarkii stomias, and Rio Grande cutthroat trout O. clarkii virginalis), mountain whitefish (Prosopium williamsoni), mottled sculpin (Cottus bairdi), longnose dace (Rhinichthys cataractae), and flathead chub (Platygobio gracilis). Aquatic invertebrate tests were conducted with mayflies (Baetis tricaudatus, Drunella doddsi, Cinygmula sp. and Ephemerella sp.), a stonefly (Chloroperlidae), and a caddis fly (Lepidostoma sp.). The amphibian test was conducted with tadpoles of the boreal toad (Bufo boreas). Median lethal concentrations (LC(50)s) ranged more than three orders of magnitude from 166 μg/L for Rio Grande cutthroat trout to >67,000 μg/L for several benthic invertebrates. Of the organisms tested, vertebrates were the most sensitive, and benthic invertebrates were the most tolerant. PMID:21811884

  9. Evolution of erythrocyte morphology in amphibians (Amphibia: Anura

    Directory of Open Access Journals (Sweden)

    Jie Wei

    2015-10-01

    Full Text Available ABSTRACT We compared the morphology of the erythrocytes of five anurans, two toad species - Bufo gargarizans (Cantor, 1842 and Duttaphrynus melanostictus (Schneider, 1799 and three frog species - Fejervarya limnocharis (Gravenhorst, 1829, Microhyla ornata (Duméril & Bibron, 1841, and Rana zhenhaiensis (Ye, Fei & Matsui, 1995. We then reconstructed the ancestral state of erythrocyte size (ES and nuclear size (NS in amphibians based on a molecular tree. Nine morphological traits of erythrocytes were all significantly different among the five species. The results of principal component analysis showed that the first component (49.1% of variance explained had a high positive loading for erythrocyte length, nuclear length, NS and ratio of erythrocyte length/erythrocyte width; the second axis (28.5% of variance explained mainly represented erythrocyte width and ES. Phylogenetic generalized least squares analysis showed that the relationship between NS and ES was not affected by phylogenetic relationships although there was a significant linear relationship between these two variables. These results suggested that (1 the nine morphological traits of erythrocytes in the five anuran species were species-specific; (2 in amphibians, larger erythrocytes generally had larger nuclei.

  10. Hemoparasites of the genus Trypanosoma (Kinetoplastida: Trypanosomatidae) and hemogregarines in Anurans of the São Paulo and Mato Grosso do Sul States - Brazil.

    Science.gov (United States)

    Leal, Denise D M; O'dwyer, Lucia H; Ribeiro, Vitor C; Silva, Reinaldo J; Ferreira, Vanda L; Rodrigues, Rozangela B

    2009-06-01

    Wild animals are exposed to numerous pathogens, including hemoparasites. The Trypanosoma and hemogregarinegroup are frequently reported as parasites in anurans (frogs, tree frogs and toads). The identification of these hemoparasites is usually made through stage observation of their morphology in the peripheral blood of the host. There areno studies, however, based on the biological cycle of these hemoparasites. The objective of the present study was toevaluate the presence of hemogregarines and Trypanosoma spp. in anurans captured in the States of São Paulo andMato Grosso do Sul- Brazil and to perform the morphological and morphometric characterization of these hemoparasites. The species of anurans examined were: Dendropsophus nanus, D. minutus, Leptodactylus chaquensis L. podicipinus, L. labyrinthicus, L. fuscus, Bufo granulosus, B. schneideri, Phyllomedusa hypocondrialis, Trachicephalus venulosus, Scinax fuscovarius and Hypsiboas albopunctatus. Of the total of 40 animals studied, four (10%)were positive for hemogregarines and eight (20%) were positive for Trypanosoma spp. Hemogregarine gamontsshowed variable morphology and, in addition to intraerythrocytic forms, extraerythrocytic forms were also observed.Extremely different forms of Trypanosoma were observed, as described in the literature, with the broad and oval forms being the most common. PMID:19488624

  11. A survey on the faunal diversity of Savar Upazila, Dhaka, Bangladesh.

    Science.gov (United States)

    Hossain, Eftekhar; Chowdhury, Mohammad Mamun; Iqubal, Kazi Farhed

    2008-02-01

    A survey was conducted during January to December 2006 to assess the status of faunal diversity of Savar Upazila, Dhaka, Bangladesh. A total of 30 species of birds, 24 species of winter birds, 7 species of reptiles, 3 species of amphibians, 15 species of mammalians and 32 species of fishes were recorded. Relative abundance of those species were determined. Of the birds, House Sparrow (Passer domesticus) was abundant while Blyth's Kingfisher (Alcedo hercules), Rock Eagle Owl (Bubo bengalensis), Hooded Pitta (Pitta sordida), Black-headed Oriole (Oriolus xanthornus), White-winged Duck (Cairina seululala) and Duck (Anser indicus) were rare. The relative abundance of winter bird could not be assessed because of their migratory habit. Striped keelback (Amphiesma stolata) and Common Smooth Water Snake (Enhydris enhydris) were very common while Black pond turtle (Geoclyms hamiltonii) and Pond tortoise (Melanochelys trijuga) were recorded as endangered. Common Toad (Bufo melanostictus) were abundant but Bull Frog (Rana tigrina) was rare. Asiatic Wild Dog (Cuon alpinus) and House Mouse (Mus musculus) were abundant while Common Otter, Large Indian Civet, Irrawaddy River Dolphin, Indian Hare were rare. Carpu, Silver carp, Tilapia, Nilotica were abundant while, Freshwater Garfish, One stripe spinyeel and Grey Featherback were rare. Landfilling, deforestation, poaching, industrial effluents and current jal were identified as major threats to the faunal diversity of Savar area. PMID:18817158

  12. Widespread amphibian extinctions from epidemic disease driven by global warming.

    Science.gov (United States)

    Pounds, J Alan; Bustamante, Martín R; Coloma, Luis A; Consuegra, Jamie A; Fogden, Michael P L; Foster, Pru N; La Marca, Enrique; Masters, Karen L; Merino-Viteri, Andrés; Puschendorf, Robert; Ron, Santiago R; Sánchez-Azofeifa, G Arturo; Still, Christopher J; Young, Bruce E

    2006-01-12

    As the Earth warms, many species are likely to disappear, often because of changing disease dynamics. Here we show that a recent mass extinction associated with pathogen outbreaks is tied to global warming. Seventeen years ago, in the mountains of Costa Rica, the Monteverde harlequin frog (Atelopus sp.) vanished along with the golden toad (Bufo periglenes). An estimated 67% of the 110 or so species of Atelopus, which are endemic to the American tropics, have met the same fate, and a pathogenic chytrid fungus (Batrachochytrium dendrobatidis) is implicated. Analysing the timing of losses in relation to changes in sea surface and air temperatures, we conclude with 'very high confidence' (> 99%, following the Intergovernmental Panel on Climate Change, IPCC) that large-scale warming is a key factor in the disappearances. We propose that temperatures at many highland localities are shifting towards the growth optimum of Batrachochytrium, thus encouraging outbreaks. With climate change promoting infectious disease and eroding biodiversity, the urgency of reducing greenhouse-gas concentrations is now undeniable. PMID:16407945

  13. The effects of dexamethasone (DXM) and vitamin A on the growth and metamorphosis of gamma irradiated, thyroxine induced Bufo melanostictus tadpoles

    International Nuclear Information System (INIS)

    This study deals with the effects of vitamin A and dexamethasone (DXM) on the metamorphosis of irradiated tadpoles. Results indicate that hypervitaminosis A depresses the metamorphosing action of thyroxine for several days. On the contrary, dexamethasone accelerates the action of exogenous thyroxine on tadpoles. Thus present data suggest that DXM supresses STH synthesis and promotes TSH secretion. Moreover, muscle appears to be its target tissue and DXM seems to promote the proteolytic digestion of the larval tail. (author)

  14. Comparative pathology and ecological implications of two myxosporean parasites in native Australian frogs and the invasive cane toad.

    Directory of Open Access Journals (Sweden)

    Ashlie Hartigan

    Full Text Available Myxosporean parasites Cystodiscus axonis and C. australis are pathogens of native and exotic Australian frog species. The pathology and ecological outcomes of infection with these parasites were investigated in this study. Gliosis was correlated to Cystodiscus axonis plasmodia in the brains of (9/60 tadpoles and (3/9 adult endangered Green and golden bell frogs using ordinal regression. Severe host reactions to C. axonis (haemorrhage, necrosis, and vasulitis were observed in the brains of threatened Southern bell frogs (8/8, critically endangered Booroolong frogs (15/44 and Yellow spotted bell frogs (3/3. Severe brain lesions were associated with behavioural changes, neurological dysfunction, and spontaneous death. Both C. axonis and C. australis develop in the bile ducts of tadpoles, the plasmodia were significantly associated with biliary hyperplasia, inflammation and the loss of hepatocytes in (34/72 Green and golden bell frog tadpoles using ordinal regression. These lesions were so severe that in some cases 70% of the total liver was diseased. Normal liver function in tadpoles is necessary for metamorphosis, metabolism, and immune function. We postulate that this extensive liver damage would have significant host health impacts. Severe hepatic myxosporidiosis was more prevalent in tadpoles examined in autumn and winter (overwintered, suggestive of delayed metamorphosis in infected tadpoles, which would have serious flow-on effects in small populations. We compared the sensitivity of histopathology and species-specific PCR in the detection of C. australis and C. axonis. PCR was determined to be the most sensitive method (detection limit 1 myxospore equivalent of ribosomal DNA. Histology, however, had the advantage of assessing the impact of the parasite on the host. It was concluded that these parasites have the potential for significant ecological impacts, because of their high prevalence of infection and their ability to cause disease in some frogs.

  15. 76 FR 70479 - Draft Environmental Assessment and Safe Harbor Agreement for the Houston Toad Within Nine Texas...

    Science.gov (United States)

    2011-11-14

    ... types that occur on the portion of the property to be enrolled, including ] accurate descriptions of vegetation, water features, and soil types; (4) current land use practices and existing development; and (5.... Box 1306, Albuquerque, New Mexico 87103 (505) 248-6651). SUPPLEMENTARY INFORMATION: Under a...

  16. Effects of a fungicide formulation on embryo-larval development, metamorphosis, and gonadogenesis of the South American toad Rhinella arenarum.

    Science.gov (United States)

    Svartz, Gabriela; Meijide, Fernando; Pérez Coll, Cristina

    2016-07-01

    Sublethal toxicity of the formulated fungicide Maxim(®) XL on embryonic, larval and juvenile development of Rhinella arenarum was evaluated by means of standardized bioassays. Maxim(®) XL, one of the most used fungicides in Argentina, is based on a mixture of two active ingredients: Fludioxonil and Metalaxyl-M. Maxim(®) XL exposure induced severe sublethal effects on the embryos, expressed as general underdevelopment, axial flexures, microcephaly, cellular dissociation, abnormal pigmentation, underdeveloped gills, marked edema and wavy tail. As the embryo development advanced, alterations in behavior as spasmodic contractions, general weakness and inanition were observed. Maxim(®) XL did not affect neither the time required to complete metamorphosis nor sex proportions, but gonadal development and differentiation were impaired. Gross gonadal analysis revealed a significant proportion of exposed individuals with underdevelopment of one or both gonads. Histological analysis confirmed that 18% and 10% of the individuals exposed to 0.25 and 2mg/L Maxim(®) XL, respectively, exhibited undifferentiated gonads characterized by a reduced number (or absence) of germ cells. Taking into account the risk evaluation performed by means of Hazard Quotients, this fungicide could be a threat to R. arenarum populations under chronic exposure. This study represents the first evidence of toxic effects exerted by Maxim(®) XL on amphibians. Finally, our findings highlight the properties of this fungicide that might jeopardize non-target living species exposed to it in agricultural environments. PMID:27214195

  17. Beta-adrenergic activation of solute coupled water uptake by toad skin epithelium results in near-isosmotic transport

    DEFF Research Database (Denmark)

    Nielsen, Robert; Larsen, Erik Hviid

    2007-01-01

    of [Na+]out in agreement with Na+ self-inhibition of ENaC. Ouabain on the inside decreased I(SC)(Eqv) from 60+/-10 to 6.1+/-1.7 microA cm(-2), and J(V) from 3.34+/-0.47 to 1.40+/-0.24 nL cm(-2) x s(-1). Short-circuited preparations exhibited a linear relationship between short-circuit current and J...

  18. Biomarker Analysis of American Toad (Anaxyrus Americanus) and Grey Tree Frog (Hyla Versicolor) Tadpoles Following Exposure to Atrazine

    Science.gov (United States)

    To better understand the mode of action of atrazine in amphibians, we utilized mass spectrometry-based metabolomics to investigate the biochemical changes in two species of larval amphibians exposed to atrazine. Our objectives were to 1) Use changes in endogenous metabolites to f...

  19. Tracking Amendments to Legislation and Other Political Texts with a Novel Minimum-Edit-Distance Algorithm: DocuToads

    DEFF Research Database (Denmark)

    Hermansson, Henrik Alf Jonas; Cross, James

    2015-01-01

    Political scientists often nd themselves tracking amendments to political texts. As different actors weigh in, texts change as they are drafted and redrafted, reflecting political preferences and power. This study provides a novel solution to the problem of detecting amendments to political text......) and substantive amount of amendments made between version of texts. To illustrate the usefulness and eciency of the approach we replicate two existing studies from the field of legislative studies. Our results demonstrate that minimum edit distance methods can produce superior measures of text amendments to hand...

  20. Mechanisms of adreno- and cholinoreceptors in isolated pulmonary and systemic vasculature of the cane toad (Rhinella marina)

    DEFF Research Database (Denmark)

    Pedersen, Pil Birkefeldt Møller; Wang, Tobias; Brøndum, Emil Toft

    site of regulation of resistance and therefore holds the capacity to control blood flow and pressure. This vascular control allows amphibians to regulate their shunt, i.e. partially bypassing either the pulmonary or systemic circuit. Shunting in amphibians has been studied due to their multiple...

  1. Responses on toad tadpoles to ammonium nitrate fertilizer and predatory stress: differences between populations on a local scale

    OpenAIRE

    Ortíz-Santaliestra, Manuel E.; Fernández-Benéitez, María José; Lizana, Miguel; Marco, Adolfo

    2011-01-01

    — Agriculture-related pollution is among the major causes of global amphibian population declines. The multiple stressors to which amphibians are exposed in the field, such as predation pressure, can make agrochemicals far more deadly than when they act in isolation. Even within a small area, diffuse agricultural pollution does not affect all aquatic environments equally, which could account for local differences in amphibian sensitivity to agrochemicals. We examined the combined effects of am...

  2. Tribulations of a prostate cancer trial - lessons learned from TOAD, a cancer council Victoria and Transtasman Radiation Oncology Group Trial

    International Nuclear Information System (INIS)

    Full text: From 2004-2009 a total of 226 out of a target of 750 prostate cancer patients have been randomised into the Timing of Androgen Deprivation trial between immediate and delayed androgen deprivation. A screening log was kept by participating centres for the first 928 patients, which documented the reasons for non-entry into the trial; 42.7% of screened patients were ineligible and a further 33.0% were not entered for other reasons. Fewer than 10% of patients cited not wanting to be part of a clinical trial as a reason for non-entry. Strategies to improve recruitment included broadening the eligibility criteria, encouraging international collaboration, the use and support of research nurses in the private health care environment, and the use of phone follow-up. Recruitment will be completed at the number originally intended to inform the interim analysis designed to test the validity of the statistical assumptions, and a combined survival analysis with the Canadian study is planned.

  3. Distribution of Boreal Toad Populations in Relation to Estimated UV-B Dose in Glacier National Park, Montana, USA

    Science.gov (United States)

    This work provides information on amphibian distributions as well as the range of UV-B exposure in mountain habitats, and will be of use to scientists interested in tracking changes in amphibian distributions and abundance, and spatial and temporal patterns of UV-B exposure

  4. 虎纹蛙蝌蚪对同域分布两种蝌蚪的食物选择%Prey selection by tiger frog larvae (Hoplobatrachus chinensis) of two sympatric anuran species' tadpoles

    Institute of Scientific and Technical Information of China (English)

    韦力; 林植华; 赵仁友; 陈世通

    2013-01-01

    We examined the prey selection and behavioral responses of tiger frog Hoplobatrachus chinensis larvae exposed to unpalatable and palatable sympatric prey tadpoles,Bufo melanostictus and Pelophylax nigromaculatus.We found that after a short exposure to the toxic toad tadpoles B.melanostictus,predators may learn to decrease going after unpalatable prey,subsequently it seems they may express short-term behavioral memory in order to avoid the toxic prey.In general,H.chinensis showed no preference for either any of the two prey species,which may be the result of P.nigromaculatus using behavioral performance and chemical defense as antipredatation strategies.These results facilitate further investigation of other aspects of the behavioral ecology of these three anuran species and hint at some potentially interesting possibilities of memory in choice of prey which may suggest further study.%该文以虎纹蛙(Hoplobatrachus chinensis)蝌蚪为研究对象,检测其作为捕食者对同域分布两种不同类型(可口性和非可口性)猎物蝌蚪(黑眶蟾蜍和黑斑侧褶蛙)的食物选择及行为响应.结果表明,由于该两种被捕食物种在面对其共同捕食者或天敌时采取不同的反捕食策略(化学防卫及行为表现),即虎纹蛙蝌蚪在进食具有毒素的黑眶蟾蜍(Bufo melanostictus)蝌蚪后,能够在短时间内减少对这种可口性差的食物的选择,具有短期记忆行为,而黑斑侧褶蛙(Pelophylax nigromaculatus)蝌蚪能够采用行为防卫机制以减少被捕食风险,因此,虎纹蛙蝌蚪对两种猎物蝌蚪的总体选择不表现明显倾向.该结果为这3种两栖类动物的行为生态学研究提供了基础数据.

  5. Bufotenine - A Hallucinogen in Ancient Snuff Powders of South America and a Drug of Abuse on the Streets of New York City.

    Science.gov (United States)

    Chamakura, R P

    1994-06-01

    Bufotenine, an isomer of psilocin, is a controlled Schedule I hallucinogenic substance under the New York state and Federal laws. Bufotenine was identified in 42 case samples received at the New York City Police Laboratory since May 1992. The samples were hard, resinous, dark reddish-brown material, sold on the streets as "hashish". A few other cases were also seized in Orlando and Tampa, FL. Natural sources of bufotenine are: (a) plant material, mostly seeds of the genus Anadenanthera (formerly Piptadenia); (b) plant organs of other genera; (c) toads (Bufo marinus, B. vulgaris, B. viridian, and B. avarice); and (d) mushrooms (Amanita amp, A. Citrina, A. Porphyria, and A. tomentella). The genus Anadenanthera is native to South America and West Indies. Historically, material made from seeds of genus Anadenanthera was, and in isolated areas is still, used by the native Indians of South America and West Indies. Native Indians make intoxicating snuffs from the seeds of Anadenanthera. Recently, bufotenine was identified in 1,200-year-old archaeological samples of an Anadenanthera material found in an excavated tomb in Northern Chile. Historical and published literature on the pharmacology, toxicology, and biological effects of bufotenine and bufotenine-containing material are reviewed. The case material was probably derived from the seeds of genus Andenanthera. There were no prior reported cases of this material being used outside the native Indian areas of South America and West Indies. Indications are that in New York City this material is smoked in combination with marijuana. Bufotenine in case material can be identified by color test, thin-layer chromatography, and gas chromatography/mass spectrometry (GC/MS). Though the mass spectra of bufotenine and psilocin (parent compounds and mono-acetyl and di-acetyl derivatives) are very similar, their GC retention times are different. Case samples also gave multiple GC peaks, probably due to the added ingredients during the

  6. Do habitat variables correlate anuran abundance in arid terrain of Rawalpindi–Islamabad Areas, Pakistan?

    Directory of Open Access Journals (Sweden)

    Ayesha Akram

    2015-07-01

    Full Text Available The quantification of anuran abundance and habitat provides valuable baseline data for future monitoring in areas of planned or anticipated human activities. We carried out the present study to see if anuran abundance is associated with habitat variables (water quality, gravel size and vegetation in Rawalpindi–Islamabad Area, Pakistan. We used area-constrained searches and quadrat method to gather data on anuran abundance and vegetation diversity, respectively, from September, 2012 to July, 2013. We recorded 28 ± 4.83 (mean number ± SE individuals of six anuran species from the study area. We recorded Euphlyctis cyanophlyctis (10 ± 2.39 as the most abundant anuran species while Microhyla ornata (<1 ± 0.09 as the least abundant species. The Kernel regression revealed strong and statistically significant association between habitat variables and abundance of Hoplobatrachus tigerinus (R2 = 0.678 and Bufo stomaticus (R2 = 0.624 but weak and statistically significant association between habitat variables and abundance of E. cyanophlyctis (R2 = 0.482; Duttaphrynus melanostictus (R2 = 0. 451; M. ornata (R2 = 0.223 and Limnonectes limnocharis (R2 = 0. 006. We concluded that the common frogs and toads in our area belong to families Dicroglossidae and Bufonidae while uncommon frogs are of family Microhylidae. We suggest inclusion of monitoring of water quality (dissolved oxygen and pH and maintenance of native wild vegetation particularly herbs, shrubs and hydrophytes of the area in the on-going and proposed development schemes of Rawalpindi–Islamabad Areas.

  7. What we know and don't know about amphibian declines in the West

    Science.gov (United States)

    Corn, Paul Stephen

    1994-01-01

    The problem of declining amphibian species is thought to be particularly acute in western North America, but there are many gaps in our knowledge. Although several declines have been well-documented, other declines are anecdotal or hypothesized. Most documented declines are of ranid frogs or toads (Bufo). Species from montane habitats and those occurring in California have been best studied. Status of many desert species is unknown. Habitat destruction and introduced predators are the most common threats to amphibian populations. Some declines may represent natural variation in population size. Causes have not been determined for several cases where common species have declined over large areas. There are important considerations for ecosystem management, whether changes in amphibian populations are natural or caused by human activities. Causes for declines must be known so that management can be prescribed (or proscribed) to eliminate or minimize these causes. The natural variability of amphibian population numbers and the complexity of metapopulation structure emphasize the necessity of considering multiple temporal and spatial scales in ecosystem management. The decline of amphibian species throughout the world has received considerable recent attention (e.g., Blaustein and Wake 1990, Griffiths and Beebee 1992, Yoffe 1992). Much of this attention derives from a workshop held in February, 1990 on declining amphibians sponsored by the National Research Council Board (NRC) on Biology in Irvine, California (Barinaga 1990, Borchelt 1990). Because of media attention in the aftermath of this conference, it is a popular perception that amphibian declines are a new phenomenon that herpetologists have been slow to recognize (Griffiths and Beebee 1992, Quammen 1993). However, concern about amphibian populations in the United States dates back over 20 years. Beginning in the 1960s, a large, well-documented decline of northern leopard frogs (Rana pipiens) occurred in the

  8. Evaluating Amphibian Declines with Site Revisits and Occupancy Models: Status of Montane Anurans in the Pacific Northwest USA

    Directory of Open Access Journals (Sweden)

    Brome McCreary

    2009-12-01

    Full Text Available Amphibian declines have been reported in mountainous areas around the western USA. Few data quantify the extent of population losses in the Pacific Northwest, a region in which amphibian declines have received much attention. From 2001–2004, we resurveyed historical breeding sites of two species of conservation concern, the Western Toad (Bufo [=Anaxyrus] boreas and Cascades Frog (Rana cascadae. We detected B. boreas breeding at 75.9% and R. cascadae breeding at 66.6% of historical sites. When we analyzed the data using occupancy models that accounted for detection probability, we estimated the current use of historically occupied sites in our study area was 84.9% (SE = 4.9 for B. boreas and 72.4% (SE = 6.6 for R. cascadae. Our ability to detect B. boreas at sites where they were present was lower in the first year of surveys (a low snowpack year and higher at sites with introduced fish. Our ability to detect R. cascadae was lower at sites with fish. The probability that B. boreas still uses a historical site for breeding was related to the easting of the site (+ and the age of record (-. None of the variables we analyzed was strongly related to R. cascadae occupancy. Both species had increased odds of occupancy with higher latitude, but model support for this variable was modest. Our analysis suggests that while local losses are possible, these two amphibians have not experienced recent, broad population losses in the Oregon Cascades. Historical site revisitation studies such as ours cannot distinguish between population losses and site switching, and do not account for colonization of new habitats, so our analysis may overestimate declines in occupancy within our study area.

  9. Coincident mass extirpation of neotropical amphibians with the emergence of the infectious fungal pathogen Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Cheng, Tina L; Rovito, Sean M; Wake, David B; Vredenburg, Vance T

    2011-06-01

    Amphibians highlight the global biodiversity crisis because ∼40% of all amphibian species are currently in decline. Species have disappeared even in protected habitats (e.g., the enigmatic extinction of the golden toad, Bufo periglenes, from Costa Rica). The emergence of a fungal pathogen, Batrachochytrium dendrobatidis (Bd), has been implicated in a number of declines that have occurred in the last decade, but few studies have been able to test retroactively whether Bd emergence was linked to earlier declines and extinctions. We describe a noninvasive PCR sampling technique that detects Bd in formalin-preserved museum specimens. We detected Bd by PCR in 83-90% (n = 38) of samples that were identified as positive by histology. We examined specimens collected before, during, and after major amphibian decline events at established study sites in southern Mexico, Guatemala, and Costa Rica. A pattern of Bd emergence coincident with decline at these localities is revealed-the absence of Bd over multiple years at all localities followed by the concurrent emergence of Bd in various species at each locality during a period of population decline. The geographical and chronological emergence of Bd at these localities also indicates a southbound spread from southern Mexico in the early 1970s to western Guatemala in the 1980s/1990s and to Monteverde, Costa Rica by 1987. We find evidence of a historical "Bd epidemic wave" that began in Mexico and subsequently spread to Central America. We describe a technique that can be used to screen museum specimens from other amphibian decline sites around the world.

  10. Aphrodisiacs past and present: a historical review.

    Science.gov (United States)

    Sandroni, P

    2001-10-01

    The drug Viagra (sildenafil) has drawn public attention to aphrodisiacs. The search for such substances dates back millennia. Aphrodisiacs can be classified by their mode of action into 3 types: those that increase (1) libido, (2) potency, or (3) sexual pleasure. Various substances of animal and plant origin have been used in folk medicines of different cultures; some have been identified pharmacologically, allowing for understanding of their mechanisms of action. For increasing libido, ambrein, a major constituent of Ambra grisea, is used in Arab countries. This tricyclic triterpene alcohol increases the concentration of several anterior pituitary hormones and serum testosterone. Bufo toad skin and glands contain bufotenine (and other bufadienolides), a putative hallucinogenic congener of serotonin. It is the active ingredient in West Indian "love stone" and the Chinese medication chan su. The aphrodisiac properties are likely of central origin, as are the other effects of the drug. For increasing potency, Panax ginseng used in traditional Chinese medicine, works as an antioxidant by enhancing nitric oxide synthesis in the endothelium of many organs, including the corpora cavernosa; ginsenosides also enhance acetylcholine-induced and transmural nerve stimulation-activated relaxation associated with increased tissue cyclic guanosine monophosphate, hence the aphrodisiac properties. For increasing sexual pleasure, cantharidin ("Spanish fly") is a chemical with vesicant properties derived from blister beetles, which have been used for millennia as a sexual stimulant. Its mode of action is by inhibition of phosphodiesterase and protein phosphatase activity and stimulation of beta-receptors, inducing vascular congestion and inflammation. Morbidity from its abuse is significant. The ingestion of live beetles (Palembus dermestoides) in Southeast Asia and triatomids in Mexico may have a basis similar to cantharidin. It is of paramount importance for the physician to be

  11. Responses of pond-breeding amphibians to wildfire: Short-term patterns in occupancy and colonization

    Science.gov (United States)

    Hossack, B.R.; Corn, P.S.

    2007-01-01

    Wildland fires are expected to become more frequent and severe in many ecosystems, potentially posing a threat to many sensitive species. We evaluated the effects of a large, stand-replacement wildfire on three species of pond-breeding amphibians by estimating changes in occupancy of breeding sites during the three years before and after the fire burned 42 of 83 previously surveyed wetlands. Annual occupancy and colonization for each species was estimated using recently developed models that incorporate detection probabilities to provide unbiased parameter estimates. We did not find negative effects of the fire on the occupancy or colonization rates of the long-toed salamander (Ambystoma macrodactylum). Instead, its occupancy was higher across the study area after the fire, possibly in response to a large snowpack that may have facilitated colonization of unoccupied wetlands. Naïve data (uncorrected for detection probability) for the Columbia spotted frog (Rana luteiventris) initially led to the conclusion of increased occupancy and colonization in wetlands that burned. After accounting for temporal and spatial variation in detection probabilities, however, it was evident that these parameters were relatively stable in both areas before and after the fire. We found a similar discrepancy between naïve and estimated occupancy of A. macrodactylum that resulted from different detection probabilities in burned and control wetlands. The boreal toad (Bufo boreas) was not found breeding in the area prior to the fire but colonized several wetlands the year after they burned. Occupancy by B. boreas then declined during years 2 and 3 following the fire. Our study suggests that the amphibian populations we studied are resistant to wildfire and that B. boreas may experience short-term benefits from wildfire. Our data also illustrate how naïve presence–non-detection data can provide misleading results.

  12. Chytridiomycosis widespread in Anurans of Northeastern United States

    Science.gov (United States)

    Longcore, J.R.; Longcore, J.E.; Pessier, Allan P.; Halteman, W.A.

    2007-01-01

    An emerging disease of amphibians caused by the chytrid fungus Batrachochytrium dendrobatidis has been associated with morbidity, mortality, and extinction of species. Typically, researchers have detected B. dendrobatidis only when examining amphibians for causes of mortalities; few data exist on infection rates where mortalities are lacking. During May?September 2000?2002 we obtained amphibian specimens killed by vehicles and others collected at remote off-road sites throughout Maine, USA, and from federal lands in 5 states in the Northeast. We detected infected specimens, mostly green frogs (Rana clamitans), at 5 of 7 national wildlife refuges, a federal waterfowl production area, and Acadia National Park. Seven of 9 species, including all Ranidae species, were infected throughout Maine; rates ranged from 14.6% in American toads (Bufo americanus) to 25.7% in northern leopard frogs (Rana pipiens). We did not detect any infections in 50 eastern gray tree frogs (Hyla versicolor) or 21 spring peepers (Pseudacris crucifer). Species that hibernate in terrestrial habitats seem to have lower rates of infection than species that hibernate in aquatic habitats. Infections peaked in spring and autumn and were associated with air temperatures optimal for B. dendrobatidis growth. The relatively high infection rates among species without documented die-offs suggest that either losses have occurred undetected, that the fungus is endemic and species have attained a level of resistance to infections becoming lethal, or that climatic conditions of the Northeast have a role in preventing infections from being lethal. Data on prevalence and distribution of this chytrid fungus in the Northeast may be useful in modeling its origins and predicting long-term ecosystem effects involving anurans.

  13. Making leaps in amphibian ecotoxicology: translating individual-level effects of contaminants to population viability.

    Science.gov (United States)

    Willson, J D; Hopkins, W A; Bergeron, C M; Todd, B D

    2012-09-01

    Concern that environmental contaminants contribute to global amphibian population declines has prompted extensive experimental investigation, but individual-level experimental results have seldom been translated to population-level processes. We used our research on the effects of mercury (Hg) on American toads (Bufo americanus) as a model for bridging the gap between individual-level contaminant effects and amphibian population viability. We synthesized the results of previous field and laboratory studies examining effects of Hg throughout the life cycle of B. americanus and constructed a comprehensive demographic population model to evaluate the consequences of Hg exposure on population dynamics. Our model explicitly considered density-dependent larval survival, which is known to be an important driver of amphibian population dynamics, and incorporated two important factors that have seldom been considered in previous amphibian modeling studies: environmental stochasticity and sublethal effects. We demonstrated that decreases in embryonic survival and sublethal effects (e.g., reduced body size) that delay maturation have minor effects on population dynamics, whereas contaminant effects that reduce late-larval or post-metamorphic survival have important population-level consequences. We found that excessive Hg exposure through maternal transfer or larval diet, alone, had minor effects on B. americanus populations. Simultaneous maternal and dietary exposure resulted in reduced population size and a dramatic increase in extinction probability, but explicit prediction of population-level effects was dependent on the strength of larval density dependence. Our results suggest that environmental contaminants can influence amphibian population viability, but that highly integrative approaches are needed to translate individual-level effects to populations.

  14. Diet quality influences isotopic discrimination among amino acids in an aquatic vertebrate.

    Science.gov (United States)

    Chikaraishi, Yoshito; Steffan, Shawn A; Takano, Yoshinori; Ohkouchi, Naohiko

    2015-05-01

    Stable nitrogen isotopic composition of amino acids (δ (15)NAA) has recently been employed as a powerful tool in ecological food web studies, particularly for estimating the trophic position (TP) of animal species in food webs. However, the validity of these estimates depends on the consistency of the trophic discrimination factor (TDF; - Δδ (15)NAA at each shift of trophic level) among a suite of amino acids within the tissues of consumer species. In this study, we determined the TDF values of amino acids in tadpoles (the Japanese toad, Bufo japonicus) reared exclusively on one of three diets that differed in nutritional quality. The diets were commercial fish-food pellets (plant and animal biomass), bloodworms (animal biomass), and boiled white rice (plant carbohydrate), representing a balanced, protein-rich, and protein-poor diet, respectively. The TDF values of two "source amino acids" (Src-AAs), methionine and phenylalanine, were close to zero (0.3-0.5‰) among the three diets, typifying the values reported in the literature (∼0.5‰ and ∼0.4‰, respectively). However, TDF values of "trophic amino acids" (Tr-AAs) including alanine, valine, leucine, isoleucine, and glutamic acid varied by diet: for example, the glutamic acid TDF was similar to the standard value (∼8.0‰) when tadpoles were fed either the commercial pellets (8.0‰) or bloodworms (7.9‰), but when they were fed boiled rice, the TDF was significantly reduced (0.6‰). These results suggest that a profound lack of dietary protein may alter the TDF values of glutamic acid (and other Tr-AAs and glycine) within consumer species, but not the two Src-AAs (i.e., methionine and phenylalanine). Knowledge of how a nutritionally poor diet can influence the TDF of Tr- and Src-AAs will allow amino acid isotopic analyses to better estimate TP among free-roaming animals.

  15. Bibliographic Studies on the Bufonis Venenum

    OpenAIRE

    Kye-Sung Kang; Gi-Rok Kwon

    2001-01-01

    Objectives : Through the literatures on the effets of Bufonis Venenum, we are finding out the clinical possibility and revealing the more effective to intractable diseases. Methods : We investigated the literatures of Oriental Medicine and experimental reports about Bufonis Venenum. Results : 1. Bufonis Venenum is made of bufonidae bufo bufo gargarizans cantor or bufo melanostictus schneider of white serum which secreted from parotid gland or dermato gland, and it is dried for using. ...

  16. Rediscovery of Pelobates fuscus insubricus in the Asti Province, north-western Italy

    OpenAIRE

    Vincenzo Mercurio; Fabrizio Li Vigni

    2007-01-01

    The amphibians of the pond complex “Stagni di Belangero” in the Po Plain, Asti Province, have been studied. The species living in the pond are Bufo bufo, Bufo viridis, Hyla intermedia, Pelobates fuscus, Rana dalmatina, Rana synklepton esculenta, Rana cf. kurtmuelleri, Triturus carnifex and Triturus vulgaris. Species composition, migration period of P. fuscus, and biometric data are provided. Relevant importance has been given to P. fuscus, since we reconfirm its presence in one...

  17. Role of Mitochondria-rich Cells for Passive Chloride Transport, discussion of Ussing's Contribution to Our Understanding of Shunt Pathways in Epithelia

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Kristensen, Poul; Nedergaard, Signe Nielsen;

    2001-01-01

    Toad skin, Mitochondria-rich cells, Chloride channels, Epithelial shunt pathways, Leaky epithelia, Recirculation theory of isotonic transport......Toad skin, Mitochondria-rich cells, Chloride channels, Epithelial shunt pathways, Leaky epithelia, Recirculation theory of isotonic transport...

  18. Drug: D06750 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available cine in Japan [BR:br08304] Crude Drugs Drugs for external use Drugs for external use D06750 Toad venom Crude drugs [BR:br08305] Animals Amphibians D06750 Toad venom PubChem: 47208401 ...

  19. 敌百虫和吡虫啉对中华蟾蜍蝌蚪的复合毒性%Co-toxicity Research of Dipterex and Imidacloprid to Bufo gargarizans Tadpole

    Institute of Scientific and Technical Information of China (English)

    刘慧君; 郭聪; 刘鉴樟; 乔巧

    2008-01-01

    [目的] 为了评价吡虫啉和敌百虫对水生生物的复合毒性.[方法] 以中华蟾蜍蝌蚪为指示生物,研究吡虫啉、敌百虫以及这2种农药混合作用下的急性毒性.[结果] 在吡虫啉安全浓度下,敌百虫对中华蟾蜍蝌蚪的LC50值约为单剂的0.6;在敌百虫安全浓度下,吡虫啉对蝌蚪的LC50值约为单剂的0.4.[结论] 环境中低浓度的吡虫啉、敌百虫虽然不会对中华蟾蜍蝌蚪产生毒害作用,但会大大增强敌百虫、吡虫啉对蝌蚪的毒性.

  20. Risk from radionuclides: a frog's perspective : Accumulation of 137Cs in a riparian wetland, radiation doses, and effects on frogs and toads after low-dose rate exposure

    OpenAIRE

    Stark, Karolina

    2006-01-01

    Threats from man-made radionuclides include waste issues, increasing number of power plants, underground bomb testing, nuclear weapons, and “dirty bombs”. Until recently the ionizing radiation protection system focused on protecting humans with an implied protection of biota. However, goals of sustainable development and precautionary principles for human activity are leading to an inclusion of plant and animal populations in the protection system. From this perspective, the present thesis ex...

  1. Scaling new heights: first record of Boulenger’s Lazy Toad Scutiger boulengeri (Amphibia: Anura: Megophryidae from high altitude lake in Sikkim Himalaya, India

    Directory of Open Access Journals (Sweden)

    Barkha Subba

    2015-08-01

    Full Text Available Frogs in the genus Scutiger of the family Megophryidae are the highest altitude frogs in the world, and are endemic to eastern Himalaya. Here, we report the occurrence of Scutiger boulengeri (Bedriaga, 1898 in one of the highest altitude lakes in the world, Lake Gurudongmar. This is the first report of Scutiger boulengeri from India and the first record of any amphibian species to be found at an altitude as high as 5270m, thus setting a world record for the highest altitude frog. Scutiger sikimmensis (Blyth, 1855 is another species of the genus Scutiger found in this region. This species is often confused with Scutiger boulengeri due to similar morphology and habitat overlap. We provide a detailed account of both S. boulengeri and S. sikimmensis based on morphology and molecular identification techniques. 

  2. Exploring the Genetic Basis of Adaptation to High Elevations in Reptiles: A Comparative Transcriptome Analysis of Two Toad-Headed Agamas (Genus Phrynocephalus)

    Science.gov (United States)

    Yang, Weizhao; Qi, Yin; Fu, Jinzhong

    2014-01-01

    High elevation adaptation offers an excellent study system to understand the genetic basis of adaptive evolution. We acquired transcriptome sequences of two closely related lizards, Phrynocephalus przewalskii from low elevations and P. vlangalii from high elevations. Within a phylogenetic framework, we compared their genomic data along with green anole, chicken and Chinese softshell turtle, and identified candidate genes and functional categories that are potentially linked to adaptation to high elevation environments. More than 100 million sequence reads were generated for each species via Illumina sequencing. A de novo assembly produced 70,919 and 62,118 transcripts for P. przewalskii and P. vlangalii, respectively. Based on a well-established reptile phylogeny, we detected 143 positively selected genes (PSGs) along the P. vlangalii lineage from the 7,012 putative orthologs using a branch-site model. Furthermore, ten GO categories and one KEGG pathway that are over-represented by PSGs were recognized. In addition, 58 GO categories were revealed to have elevated evolutionary rates along the P. vlangalii lineage relative to P. przewalskii. These functional analyses further filter out PSGs that are most likely involved in the adaptation process to high elevations. Among them, ADAM17, MD, and HSP90B1 likely contributed to response to hypoxia, and POLK likely contributed to DNA repair. Many other candidate genes involved in gene expression and metabolism were also identified. Genome-wide scan for candidate genes may serve as the first step to explore the genetic basis of high elevation adaptation. Detailed comparative study and functional verification are needed to solidify any conclusions. High elevation adaptation requires coordinated changes in multiple genes that involve various physiological and biochemical pathways; we hope that our genetic studies will provide useful directions for future physiological or molecular studies in reptiles as well as other poikilothermic species. PMID:25386640

  3. Historical biogeography resolves the origins of endemic Arabian toad lineages (Anura: Bufonidae): Evidence for ancient vicariance and dispersal events with the Horn of Africa and South Asia

    OpenAIRE

    Portik, Daniel M; Papenfuss, Theodore J.

    2015-01-01

    Background The Arabian Peninsula is home to a unique fauna that has assembled and evolved throughout the course of major geophysical events, including the separation of the Arabian Plate from Africa and subsequent collision with Eurasia. Opportunities for faunal exchanges with particular continents occurred in temporally distinct periods, and the presence of African, Western Eurasian, and South Asian derived taxa on the Arabian Peninsula signifies the complexity of these historical biogeograp...

  4. Geographic variation in Incilius occidentalis (Anura: Bufonidae), an endemic toad from Mexico, with a redescription of the species and delimitation of the type locality

    OpenAIRE

    Georgina Santos-Barrera

    2014-01-01

    A taxonomic revision of the populations referable to the wide ranging species Incilius occidentalis was conducted based on 10 morphometric variables and other external morphological traits. Thirty three populations were geographically defined from more than 220 locality records of the species. A brief summary of the nomenclatural history of this species is presented and the external morphological variation is analyzed. Incilius occidentalis is here redescribed on the basis of comparisons with...

  5. Membrane potentials and intracellular Cl- activity of toad skin epithelium in relation to activation and deactivation of the transepithelial Cl- conductance

    DEFF Research Database (Denmark)

    Willumsen, N J; Larsen, Erik Hviid

    1986-01-01

    , but was independent of whether the external bath was NaCl-Ringer's, NaCl-Ringer's with amiloride, KCl-Ringer's or choline Cl-Ringer's. To partition the routes of the conductive Cl- ion flow, we measured in the isolated epithelium with double-barrelled microelectrodes apical membrane potential. Va, and intracellular...

  6. Effect of Uncaria rhynchophyla Mig.jackas on the heart of toad%钩藤对蟾蜍心脏的作用机制研究

    Institute of Scientific and Technical Information of China (English)

    唐省三

    2002-01-01

    目的:探讨钩藤对蟾蜍心脏的作用.方法:用钩藤灌流蟾蜍心脏,观察灌流前后心肌收缩力、心输出量和心率的变化.结果心肌收缩幅度减小、心输出量减少和心率变慢.结论:钩藤对蟾蜍心脏有抑制作用,从而降低血压.

  7. Range extension of Ferguson Toad Duttaphrynus scaber (Schneider (Amphibia: Anura: Bufonidae up to the northern most limit of Western Ghats, with its advertisement call analysis

    Directory of Open Access Journals (Sweden)

    A. Padhye

    2013-07-01

    Full Text Available Duttaphrynus scaber (Schneider is known to occur in the southern Western Ghats, Eastern Ghats and northeastern India. However, there is no report of its occurrence from the northern Western Ghats from the states of Maharashtra and Gujarat. Here we report the occurrence of this species from the northernmost limit of the Western Ghats, a substantial range extension (approx. 550km from the nearest known locality. We confirm our identification on the basis of morphology by comparing our specimens with a previously collected Duttaphrynus scaber specimen from Thrissur in Kerala State as well as on the molecular basis. Analysis based on the advertisement call of Duttaphrynus scaber, albeit preliminary, is provided for the first time for this species.

  8. A new genus of Toads (Amphibia: Anura: Bufonidae) from the Pacific Slopes of the Andes in Northern Ecuador and Southern Colombia, with the description of two new species

    NARCIS (Netherlands)

    Hoogmoed, M.S.

    1985-01-01

    The genus Andinophryne, characterized by the presence of an omosternum, an externally visible tympanum, elongate parotoids and extensively webbed hands and feet is described from the Pacific versant of the Andes in northwestern Ecuador and southwestern Colombia. Two new species, Andinophryne colomai

  9. Hemoparasites of the genus Trypanosoma (Kinetoplastida: Trypanosomatidae and hemogregarines in Anurans of the São Paulo and Mato Grosso do Sul States - Brazil

    Directory of Open Access Journals (Sweden)

    Denise D.M. Leal

    2009-06-01

    Full Text Available Wild animals are exposed to numerous pathogens, including hemoparasites. The Trypanosoma and hemogregarinegroup are frequently reported as parasites in anurans (frogs, tree frogs and toads. The identification of these hemoparasites is usually made through stage observation of their morphology in the peripheral blood of the host. There areno studies, however, based on the biological cycle of these hemoparasites. The objective of the present study was toevaluate the presence of hemogregarines and Trypanosoma spp. in anurans captured in the States of São Paulo andMato Grosso do Sul- Brazil and to perform the morphological and morphometric characterization of these hemoparasites. The species of anurans examined were: Dendropsophus nanus, D. minutus, Leptodactylus chaquensis L. podicipinus, L. labyrinthicus, L. fuscus, Bufo granulosus, B. schneideri, Phyllomedusa hypocondrialis, Trachicephalus venulosus, Scinax fuscovarius and Hypsiboas albopunctatus. Of the total of 40 animals studied, four (10%were positive for hemogregarines and eight (20% were positive for Trypanosoma spp. Hemogregarine gamontsshowed variable morphology and, in addition to intraerythrocytic forms, extraerythrocytic forms were also observed.Extremely different forms of Trypanosoma were observed, as described in the literature, with the broad and oval forms being the most common.Os animais silvestres estão expostos a inúmeros patógenos,dentre eles estão os hemoparasitas. Podem-se destacar espécies do gênero Trypanosoma e do grupo das hemogregarinas,que ocorrem com freqüência parasitando anuros (rãs, pererecas e sapos. Normalmente, a descrição destes hemoparasitas é feita através da morfologia dos estágios observados nosangue periférico do hospedeiro e as pesquisas sobre o ciclobiológico desses hemoparasitas são escassas. Os objetivos dopresente estudo foram avaliar a presença de hemogregarinas eTrypanosoma spp. em anuros capturados nos Estados de São Paulo e

  10. Reptile and amphibian responses to large-scale wildfires in southern California

    Science.gov (United States)

    Rochester, C.J.; Brehme, C.S.; Clark, D.R.; Stokes, D.C.; Hathaway, S.A.; Fisher, R.N.

    2010-01-01

    In 2003, southern California experienced several large fires that burned thousands of hectares of wildlife habitats and conserved lands. To investigate the effects of these fires on the reptile and amphibian communities, we compared the results from prefire herpetofauna and vegetation sampling to two years of postfire sampling across 38 burned and 17 unburned plots. The sampling plots were spread over four vegetation types and four open space areas within San Diego County. Our capture results indicated that burned chaparral and coastal sage scrub plots lost herpetofaunal species diversity after the fires and displayed a significant shift in overall community structure. Shrub and tree cover at the burned plots, averaged across the second and third postfire years, had decreased by 53 in chaparral and 75 in coastal sage scrub. Additionally, postfire herpetofauna community structure at burned plots was more similar to that found in unburned grasslands. In grassland and woodland/riparian vegetation plots, where shrub and tree cover was not significantly affected by fires, we found no differences in the herpetofaunal species diversity or community composition. At the individual species level, Sceloporus occidentalis was the most abundant reptile in these areas both before and after the fires. We saw increases in the net capture rates for several lizard species, including Aspidoscelis tigris, Phrynosoma coronatum, and Uta stansburiana in burned chaparral plots and Aspidoscelis hyperythra and U. stansburiana in burned coastal sage scrub plots. The toad, Bufo boreas, was detected at significantly fewer burned plots in chaparral after the fires. Additionally, we documented decreases in the number of plots occupied by lizards (Elgaria multicarinata), salamanders (Batrachoseps major), and snakes (Coluber constrictor, Lampropeltis getula, Pituophis catenifer, and Masticophis lateralis) in coastal sage scrub and chaparral after the fires. We discuss the individual species

  11. Rickettsia bellii in Amblyomma rotundatum ticks parasitizing Rhinella jimi from northeastern Brazil.

    Science.gov (United States)

    Horta, Mauricio C; Saraiva, Danilo G; Oliveira, Glauber M B; Martins, Thiago F; Labruna, Marcelo B

    2015-01-01

    This study evaluated rickettsial infection in Amblyomma rotundatum ticks collected from toads (Rhinella jimi) in the Brazilian Caatinga biome, an unique semiarid region of South America. Tick infestations were observed in 57.8% toads (26/45); mean infestation: 1.6 ticks/toad. DNA extraction from 42 ticks (6 larvae, 22 nymphs and 11 female adults) was tested by polymerase chain reaction (PCR) targeting Rickettsia organisms, which were detected in 100% of the ticks. Amplicons' DNA sequences were identical to each other and 99% identical to Rickettsia bellii from GenBank. DNA samples extracted from the blood of the 45 toads were negative by rickettsia-PCR protocols.

  12. Salida de campo a Traspinedo (Valladolid) el 4 de septiembre de 1952

    OpenAIRE

    Valverde Gómez, José Antonio, 1926-2003

    2008-01-01

    Salida de campo a Traspinedo (Valladolid) el 4 de septiembre de 1952, de la que se anotaron observaciones sobre Pseudochondrostoma sp. (Boga), sapos (posiblemente, el Sapo común, Bufo bufo), los siguientes reptiles: Blanus cinereus (Culebrilla ciega, también llamado Eslabon), Lagartija (sin identificar la especie), Natrix maura (Culebra viperina, llamada Tropidonotus viperinus por el autor) y Vipera sp. (Víbora)los siguientes mamíferos: Ardilla (pudiendo ser Sciurus vulgaris o Atlantoxerus ge...

  13. The effect of road kills on amphibian populations

    OpenAIRE

    Hels, Tove; Buchwald,, Erik

    2001-01-01

    The diurnal movement patterns of Triturus vulgaris, T. cristatus, Pelobates fuscus, Bufo bufo, Rana temporaria, and R. arvalis were investigated during five breeding seasons (1994-1998). Two main questions were addressed: 1) What is the probability of an individual amphibian getting killed when crossing the road? and 2) What fraction of the amphibian populations gets killed by traffic? The rate of movement of 203 adult amphibians was recorded. Information on traffic loads was provided, and mo...

  14. 黄芪对蟾蜍离体单一肌梭传入放电的影响%Effect of Radix Astragali on the discharge of isolated toad muscle spindle

    Institute of Scientific and Technical Information of China (English)

    唐斌; 樊小力; 吴苏娣

    2003-01-01

    目的探讨黄芪、丹参对肌梭传入放电的影响.方法用空气隔绝法记录蟾蜍离体单一肌梭的传入放电,观察黄芪和丹参注射液对肌梭传入电活动的影响,并与琥珀胆碱(SCh)的作用进行比较.结果应用50 mg*L-1 SCh后,肌梭的自发放电频率由(0.79±0.12) Hz增加至(12.26±2.38) Hz.应用100、200、300 mg*L-1黄芪后,肌梭的传入放电分别由(0.80±0.34) Hz、(0.77±0.29) Hz、(0.70±0.42) Hz增加至(13.18±2.43) Hz、(24.03±4.07) Hz、(36.17±5.83) Hz.丹参注射液对肌梭的传入放电没有作用.结论黄芪可以使肌梭的传入放电频率显著增加,且呈剂量依赖现象.

  15. Effect of Cordycepin on Discharge of Isolated Toad Muscle Spindle%冬虫夏草增强蟾蜍离体单一肌梭传入放电频率

    Institute of Scientific and Technical Information of China (English)

    石磊; 廉西娟; 王保成; 樊小力; 吴苏娣

    2006-01-01

    目的:探讨冬虫夏草对肌梭传入放电的影响.方法:用蟾蜍缝匠肌制备单一肌梭标本以空气隔绝法记录单一肌梭的传入放电,观察冬虫夏草水提液对肌梭传入放电的影响.结果:应用50 mg/L、100 mg/L、200 mg/L冬虫夏草水提液后,肌梭的传入放电分别由(0.85±0.12)Hz、(0.87±0.12)Hz、(0.84±0.10)Hz增加至(10.52土2.48)Hz、(20.79±3.03)Hz、(29.25±4.08)Hz.结论:冬虫夏草水提液可以使肌梭的传入放电频率明显增加,且呈剂量依赖关系.

  16. Range extension of Ferguson Toad Duttaphrynus scaber (Schneider) (Amphibia: Anura: Bufonidae) up to the northern most limit of Western Ghats, with its advertisement call analysis

    OpenAIRE

    A. Padhye; Pandit, R.; Patil, R; S Gaikwad; N. Dahanukar; Y. Shouche

    2013-01-01

    Duttaphrynus scaber (Schneider) is known to occur in the southern Western Ghats, Eastern Ghats and northeastern India. However, there is no report of its occurrence from the northern Western Ghats from the states of Maharashtra and Gujarat. Here we report the occurrence of this species from the northernmost limit of the Western Ghats, a substantial range extension (approx. 550km) from the nearest known locality. We confirm our identification on the basis of morphology by comparing our spec...

  17. A toad getting a swan's flesh: review on the film If You Are The One (feicheng wurao)%癞蛤蟆吃到了天鹅肉——评《非诚勿扰》

    Institute of Scientific and Technical Information of China (English)

    胡建波

    2009-01-01

    实际上是讲了一只癞蛤蟆如何吃了天鹅肉的故事.从谁是大家心目中的天鹅、癞蛤蟆差点没吃着天鹅肉、几处拿捏得恰到好处的精彩故事、绚丽风景与爱情故事的完美融合,字字珠玑的台词等方面评论了冯导的这部经典之作.

  18. 78 FR 15737 - Incidental Take Permit Amendment and Supplemental Environmental Assessment for Wind Energy...

    Science.gov (United States)

    2013-03-12

    .... The Service previously advertised (71 FR 951), and issued in September 2006, TE104073 as a 40-year ITP... address the impacts to the Puerto Rican crested toad within the Punta Ventana section of the covered area... turbines in Guayanilla, Puerto Rico. Puerto Rican crested toads have been observed in the Punta...

  19. Cytological study on nuclear transplanted eggs by transplanting Xenopus laevis blastomere nuclei to Bufo raddei%非洲爪蟾胚胎细胞核移入花背蟾蜍成熟卵后的细胞学研究

    Institute of Scientific and Technical Information of China (English)

    司克媛; 梁桂霞; 俞诗源; 陈永龙

    2005-01-01

    @@ 在有关两栖类细胞核移植工作中,大部分工作是对移核胚胎的形态学分析(Briggs and King, 1960; DiBeradino and King, 1967; Smith,1965; Gurdon, 1974; DiBeradino et al., 1967,1971.此外是对移核胚胎染色体组型的分析(Hennen, 1963; 梁桂霞、毛铭廷,1991).

  20. Nomenclatural notes on living and fossil amphibians

    Directory of Open Access Journals (Sweden)

    Martín, C.

    2012-06-01

    Full Text Available A review of extinct and living amphibians known from fossils (Allocaudata, Anura and Caudata has revealed several cases that require nomenclatural changes in order to stabilize the taxonomy of the group. Nomenclatural changes include homonym replacements, corrections of spelling variants and authorships, name availabilities, and in particular, the proposal of new combinations. These changes will allow the incorporation of some palaeontological taxa to the current evolutionary models of relationship of modern forms based on molecular phylogenies. Rana cadurcorum for Rana plicata Filhol, 1877, Rana auscitana for Rana pygmaea Lartet, 1851, and Rana sendoa for Rana robusta Brunner, 1956. Anchylorana Taylor, 1942 is considered a new synonym of Lithobates Fitzinger, 1843. New combinations proposed are: Anaxyrus defensor for Bufo defensor Meylan, 2005; Anaxyrus hibbardi for Bufo hibbardi Taylor, 1937; Anaxyrus pliocompactilis for Bufo pliocompactilis Wilson, 1968; Anaxyrus repentinus for Bufo repentinus Tihen, 1962; Anaxyrus rexroadensis for Bufo rexroadensis Tihen, 1962; Anaxyrus spongifrons for Bufo spongifrons Tihen, 1962; Anaxyrus suspectus for Bufo suspectus Tihen, 1962; Anaxyrus tiheni for Bufo tiheni Auffenberg, 1957; Anaxyrus valentinensis for Bufo valentinensis Estes et Tihen, 1964; Ichthyosaura wintershofi for Triturus wintershofi Lunau, 1950; Incilius praevius for Bufo praevius Tihen, 1951; Lithobates bucella for Rana bucella Holman, 1965; Lithobates dubitus for Anchylorana dubita Taylor, 1942; Lithobates fayeae for Rana fayeae Taylor, 1942; Lithobates miocenicus for Rana miocenica Holman, 1965; Lithobates moorei for Anchylorana moorei Taylor, 1942; Lithobates parvissimus for Rana parvissima

  1. Potential developmental toxicity of anatoxin-a, a cyanobacterial toxin.

    Science.gov (United States)

    Rogers, E H; Hunter, E S; Moser, V C; Phillips, P M; Herkovits, J; Muñoz, L; Hall, L L; Chernoff, N

    2005-01-01

    receiving either 0, 500 or 1,000 microg kg(-1) microcystin-LR by gavage and approximately 50 min later receiving either 0, 500, 1,000 or 2,500 microg kg(-1) anatoxin-a by the same route. No deaths occurred at any dose and no definitive signs of intoxication were observed. Stages 17 and 25 toad embryos (Bufo arenarum) were exposed to 0.03-30.0 mg l(-1) of anatoxin-a for 10 days. Adverse effects included a dose-dependent transient narcosis, edema and loss of equilibrium. Most notable was the occurrence of 100% mortality at the high dose in both groups 6-13 days post-exposure. The observed delay between initial exposure and death is highly unusual for anatoxin-a. PMID:16127666

  2. Amphibians of the Simbruini Mountains (Latium, Central Italy

    Directory of Open Access Journals (Sweden)

    Pierangelo Crucitti

    2010-07-01

    Full Text Available Little attention has been paid to the herpetological fauna of the Simbruini Mountains Regional Park, Latium (Central Italy. In this study, we surveyed 50 sites in the course of about ten years of field research, especially during the period 2005-2008. Nine amphibian species, four Caudata and five Anura, 60.0% out of the 15 amphibian species so far observed in Latium, were discovered in the protected area: Salamandra salamandra, Salamandrina perspicillata, Lissotriton vulgaris, Triturus carnifex, Bombina pachypus, Bufo balearicus, Bufo bufo, Rana dalmatina, Rana italica. Physiography of sites has been detailed together with potential threatening patterns. For each species the following topics have been discussed; ecology of sites, altitudinal distribution, phenology, sintopy. Salamandra salamandra and Bombina pachypus are at higher risk. The importance of the maintenance of artificial/natural water bodies for the conservation management of amphibian population of this territory is discussed.

  3. Phylogenetic Relationship of Duttaphrynus melanostictus From India and China as Revealed from the Study of 12S and 16S mtDNA Genes

    Directory of Open Access Journals (Sweden)

    Sanjib Kr. Das

    2013-01-01

    Full Text Available In the present study, the phylogenetic relationship of Duttaphrynus melanostictus from West Bengal, India with other members of the Bufonidiae group was undertaken using partial mitochondrial DNA (mtDNA genes. Mitochondria were isolated from the liver of Duttaphrynus melanostictus by a non-conventional method of membrane filtration. The technique allows trapping of mitochondria on cellulose acetate membrane followed by mtDNA isolation. 12S ribosomal RNA and 16S ribosomal RNA was sequenced with primers designed in our laboratory. mtDNA sequence from 18 different Bufo sp. found across the world were used for the phylogenetic analysis. Results were interpreted from the transition/transversion of nucleotides, genetic distance and maximum parsimony analysis. The findings indicates that D. melanostictus is very closely related to the Bufo melanostictus of China. The possible reasons of such close similarity between two distantly residing species (D. melanostictus of India and Bufo melanostictus of China have been discussed.

  4. Dynamic characterization of silicon nanowires using a terahertz optical asymmetric demultiplexer-based pump-probe scheme

    DEFF Research Database (Denmark)

    Ji, Hua; Cleary, C. S.; Dailey, J. M.;

    2012-01-01

    Dynamic phase and amplitude all-optical responses of silicon nanowires are characterized using a terahertz optical asymmetric demultiplexer (TOAD) based pump-probe scheme. Ultra-fast recovery is observed for moderate pump powers....

  5. Amphibian abnormalities on National Wildlife Refuges

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This fact sheet outlines a study done to 1) find the percentage of abnormal frogs and toads on the nation’s National Wildlife Refuges and 2) determine how the...

  6. Harbingers of Spring

    Science.gov (United States)

    Serrao, John

    1976-01-01

    Emphasizing the spring migration of frogs, toads, and salamanders to their watery breeding sites, this article presents information on numerous amphibians and suggests both indoor and outdoor educational activities appropriate for elementary and/or early secondary instruction. (JC)

  7. Valge fungi uus tulemine / Kersti Pikk

    Index Scriptorium Estoniae

    Pikk, Kersti

    2007-01-01

    Peeter Tambu projekteeritud valge "eestiaegne" funk eramu, kus avatud planeeringu asemel on paraja suurusega eraldi toad, esikohal ruumide otstarbekus ja ratsionaalsus. Arhitekt on kujundanud interjööri ja mööbli

  8. Rahvusvahelisel muuseumipäeval 18. V avati Tartu Kunstimuuseumis Raekoja plats 18... / Reeli Kõiv

    Index Scriptorium Estoniae

    Kõiv, Reeli

    2005-01-01

    Näituse kuraator ülevaatenäitusest "Tartu kunsti lood", mis esitab Tartu kunsti arenguloo rohkem kui pooleteise sajandi lõikes. Näitusega kaasnevad muuseumitunnid ja töötoad igas vanuses lastele ja noortele

  9. Instruction Manual and Frog Survey Protocols for Region 1 National Wildlife Refuges, East-side Zone

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This manual is intended to assist biologists wishing to conduct surveys for frogs and toads. The document includes detailed information on how to conduct surveys,...

  10. Filmifestival õpetas ise filme looma / Aarne Mäe

    Index Scriptorium Estoniae

    Mäe, Aarne, 1967-

    1999-01-01

    30. sept. - 3. okt. Rakvere Exclusiveì ööklubis toimunud Põhjamaade ja Baltikumi noorte videofilmide filmifestivali "Visions of Light" raames tegutsesid ka töötoad : Eesti nukufilmi töötuba ja "Video netis"

  11. Salida de campo a Santo Domingo de Silos, en Burgos, el 13 de septiembre de 1953

    OpenAIRE

    Valverde Gómez, José Antonio, 1926-2003

    2008-01-01

    Salida de campo a Santo Domingo de Silos, en Burgos, el 13 de septiembre de 1953, de la que se anotaron observaciones sobre los siguientes anfibios: Alytes sp. (Sapo partero), Bufo bufo (Sapo común, llamado B.vulgaris por el autor), Hyla sp. (Ranita), Lissotriton vulgaris, Rana sp. (Rana), Salamandra salamandra (Salamandra común, también llamada S.maculosa por el autor) y Triturus cristatus (Tritón crestado), los siguientes reptiles: Acanthodactylus erythrurus (Lagartija colirroja, llamada A....

  12. Salida de campo a Montejo de la Sierra (Madrid) a mediados de septiembre de 1953

    OpenAIRE

    Valverde Gómez, José Antonio, 1926-2003

    2008-01-01

    Salida de campo a Montejo de la Sierra, en Madrid, a mediados de septiembre de 1953, de la que se anotaron observaciones sobre los siguientes anfibios: Bufo bufo (Sapo común, llamado B.vulgaris por el autor) y Rana sp. (Rana), los siguientes reptiles: Natrix maura (Culebra viperina, llamada Tropidonotus viperinus por el autor) y Psammodromus sp. (Lagartija), los siguientes mamíferos: Arvicola sapidus (Rata de agua, también llamado Ratón aguadero), Martes foina (Garduña), Plecotus sp. (Orejudo...

  13. Helminthen einheimischer Froschlurche

    OpenAIRE

    Andreas, Katharina

    2010-01-01

    176 frogs of the species Rana kl. esculenta (n = 137), Rana ridibunda (n = 7), Rana temporaria (n = 19), Rana arvalis (n = 18) and Bufo bufo (n = 1) taken from 11 different habitats in the Brandenburg state and the state of Saxonia-Anhalt were dissected and helminthologically examined. One aim of this study was to show the role of indigenous frogs in the epidemiology of trematode infections of carnivorous mammals and birds more closely, and also to attain details the incidence of frogs wi...

  14. Schulzia chiribita n. sp. (Nematoda, Trichostrongylina, Molineoidea) parasite of Leptodactylus rhodonotus (Amphibian) from Peru.

    Science.gov (United States)

    Durette-Desset, M C; Florindez, D T; Morales, E

    2000-03-01

    A third species of the genus Schulzia Travassos, 1937 a parasite of Leptodactylus rhodonotus (Amphibian, Leptodactylidae) originating from Peru is described. By the pattern of the caudal bursa, the specimens are closely related to the two other species. They are distinguished from Schulzia uzu Lent & Santos, 1989, parasite from Atelopus oxyrhynchus in Venezuela, by the shape of the ovejector and from Schulzia travassosi Durette-Desset, Baker & Vaucher, 1985, parasite from Bufo crucifer in Brasil, Bufo granulosus and Leptodactylus bufonius in Paraguay, by the shape of the spicules. The presence of a new species in Peru points out the wide geographic distribution of the genus in the Neotropical region. PMID:10743644

  15. Schulzia chiribita n. sp. (Nematoda, Trichostrongylina, Molineoidea parasite of Leptodactylus rhodonotus (Amphibian from Peru

    Directory of Open Access Journals (Sweden)

    Durette-Desset M.C.

    2000-03-01

    Full Text Available A third species of the genus Schulzia Travassos, 1937 a parasite of Leptodactylus rhodonotus (Amphibian, Leptodactylidae originating from Peru is described. By the pattern of the caudal bursa, the specimens are closely related to the two other species. They are distinguished from Schulzia uzu Lent & Santos, 1989, parasite from Atelopus oxyrhynchus in Venezuela, by the shape of the ovejector and from Schulzia travassosi Durette-Desset, Baker & Vaucher, 1985, parasite from Bufo crucifer in Brasil, Bufo granulosus and Leptodactylus bufonius in Paraguay, by the shape of the spicules. The presence of a new species in Peru points out the wide geographic distribution of the genus in the Neotropical region.

  16. Can protected mountain areas serve as refuges for declining amphibians? Potential threats of climate change and amphibian chytridiomycosis in an alpine amphibian population. eco.mont (Journal on Protected Mountain Areas Research)|eco.mont Vol. 1 No. 2|

    OpenAIRE

    Sztatecsny, Marc; Hödl, Walter

    2009-01-01

    In June 2004 and June 2005, we checked 40 and 134 ponds respectively for alive and dead alpine newts, common toads, common frogs, and their clutches on the "Kirchfeld" plateau in the Northern Limestone Alps of Austria. We found several hundred dead common frogs and alpine newts in the two consecutive years and also observed an unusually high number of heterospecific matings between common toads and common frogs in 2004. In order to test whether the observed mortalities were caused by disease,...

  17. The herpetofauna of Timor-Leste: a first report

    OpenAIRE

    Hinrich Kaiser; Venancio Lopes Carvalho; Jester Ceballos; Paul Freed; Scott Heacox; Barbara Lester; Richards, Stephen J.; Trainor, Colin R.; Caitlin Sanchez; Mark O’Shea

    2011-01-01

    Abstract Fieldwork conducted throughout Timor-Leste in September 2004 and July 2009 resulted in a collection or recording of 263 herpetological specimens (100 amphibians, 163 reptiles), comprising at least seven species of frogs and toads, 20 species of lizards, seven species of snakes, two species of turtles, and one species of crocodile. Among the amphibians, the most frequently encountered species were toads ( Duttaphrynus melanostictus ), rice paddy frogs (genus Fejervarya ), and rhacopho...

  18. Disease in a dynamic landscape: host behavior and wildfire reduce amphibian chytrid infection

    Science.gov (United States)

    Hossack, Blake R.; Lowe, Winsor H.; Ware, Joy L.; Corn, Paul Stephen

    2013-01-01

    Disturbances are often expected to magnify effects of disease, but these effects may depend on the ecology, behavior, and life history of both hosts and pathogens. In many ecosystems, wildfire is the dominant natural disturbance and thus could directly or indirectly affect dynamics of many diseases. To determine how probability of infection by the aquatic fungus Batrachochytrium dendrobatidis (Bd) varies relative to habitat use by individuals, wildfire, and host characteristics, we sampled 404 boreal toads (Anaxyrus boreas boreas) across Glacier National Park, Montana (USA). Bd causes chytridiomycosis, an emerging infectious disease linked with widespread amphibian declines, including the boreal toad. Probability of infection was similar for females and the combined group of males and juveniles. However, only 9% of terrestrial toads were infected compared to >30% of aquatic toads, and toads captured in recently burned areas were half as likely to be infected as toads in unburned areas. We suspect these large differences in infection reflect habitat choices by individuals that affect pathogen exposure and persistence, especially in burned forests where warm, arid conditions could limit Bd growth. Our results show that natural disturbances such as wildfire and the resulting diverse habitats can influence infection across large landscapes, potentially maintaining local refuges and host behaviors that facilitate evolution of disease resistance.

  19. On the parasitic fauna of two species of anurans collected from Sungai Pinang, Penang Island, Malaysia.

    Science.gov (United States)

    Wahab, A R; Andy Tan, W A; Intan, S

    2008-08-01

    A total of fifty anurans, comprising of Rana limnocharis and Bufo melanostictus were collected from Sungai Pinang, Balik Pulau, Penang. The prevalence, mean intensity and distribution of parasite species along the digestive tract were reported. Seven species of parasites were recorded. Blood parasites recovered were trypansomes and microfilariae.

  20. Drug: D00595 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available diabetics Anatomical Therapeutic Chemical (ATC) classification [BR:br08303] A ALIMENTARY TRACT AND METABOLISM A10 DRUGS USED IN DIABE...TES A10B BLOOD GLUCOSE LOWERING DRUGS, EXCL. INSULINS A10BA Biguanides A10BA03 Bufo

  1. Revisão do gênero Satipoella (Coleoptera, Cerambycidae, Lamiinae Revision of the genus Satipoella (Coleoptera, Cerambycidae, Lamiinae

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo de Alvarenga Julio

    2003-06-01

    Full Text Available The genus Satipoella Lane, 1964 is revised and a new synonym is proposed, Icarai Galileo & Martins, 1998, with Satipoella. A new species, S. ochroma, is described from Amazonas, Brazil. New combination: Satipoella bufo (Thomson, 1864 from Icarai. The three species of Satipoella are illustrated and keyed.

  2. Revisão do gênero Satipoella (Coleoptera, Cerambycidae, Lamiinae)

    OpenAIRE

    Julio Carlos Eduardo de Alvarenga

    2003-01-01

    The genus Satipoella Lane, 1964 is revised and a new synonym is proposed, Icarai Galileo & Martins, 1998, with Satipoella. A new species, S. ochroma, is described from Amazonas, Brazil. New combination: Satipoella bufo (Thomson, 1864) from Icarai. The three species of Satipoella are illustrated and keyed.

  3. Revisão do gênero Satipoella (Coleoptera, Cerambycidae, Lamiinae) Revision of the genus Satipoella (Coleoptera, Cerambycidae, Lamiinae)

    OpenAIRE

    Carlos Eduardo de Alvarenga Julio

    2003-01-01

    The genus Satipoella Lane, 1964 is revised and a new synonym is proposed, Icarai Galileo & Martins, 1998, with Satipoella. A new species, S. ochroma, is described from Amazonas, Brazil. New combination: Satipoella bufo (Thomson, 1864) from Icarai. The three species of Satipoella are illustrated and keyed.

  4. Persistence of the emerging pathogen Batrachochytrium dendrobatidis outside the amphibian host greatly increases the probability of host extinction.

    Science.gov (United States)

    Mitchell, Kate M; Churcher, Thomas S; Garner, Trenton W J; Fisher, Matthew C

    2008-02-01

    Pathogens do not normally drive their hosts to extinction; however, Batrachochytrium dendrobatidis, which causes amphibian chytridiomycosis, has been able to do so. Theory predicts that extinction can be caused by long-lived or saprobic free-living stages. The hypothesis that such a stage occurs in B. dendrobatidis is supported by the recent discovery of an apparently encysted form of the pathogen. To investigate the effect of a free-living stage of B. dendrobatidis on host population dynamics, a mathematical model was developed to describe the introduction of chytridiomycosis into a breeding population of Bufo bufo, parametrized from laboratory infection and transmission experiments. The model predicted that the longer that B. dendrobatidis was able to persist in water, either due to an increased zoospore lifespan or saprobic reproduction, the more likely it was that it could cause local B. bufo extinction (defined as decrease below a threshold level). Establishment of endemic B. dendrobatidis infection in B. bufo, with severe host population depression, was also possible, in agreement with field observations. Although this model is able to predict clear trends, more precise predictions will only be possible when the life history of B. dendrobatidis, including free-living stages of the life cycle, is better understood. PMID:18048287

  5. The Test Observation of Electrical Physiology about the Exhausted Recovery of a Toad's Calf Intestines Muscle Specimen by Acupuncture%关于针刺对蟾蜍腓肠肌标本疲劳恢复的电生理实验观察

    Institute of Scientific and Technical Information of China (English)

    黄琰

    2002-01-01

    以蟾蜍为实验对象,对蟾蜍腓肠肌标本进行电刺激收缩达到一定的疲劳程度后,分别采取休息和针刺方法恢复,观察整个过程中的肌肉收缩曲线并分析.实验结果显示:针刺可以大幅度地提高肌肉在疲劳后恢复中的最大用力.

  6. A New Time-Based Algorithm for Positioning Mobile Terminals in Wireless Networks

    Directory of Open Access Journals (Sweden)

    Francisco Barcelo-Arroyo

    2008-03-01

    Full Text Available This paper presents a positioning algorithm, named time of arrival to time difference of arrival (TOAD, which computes time-difference-of-arrival (TDOA measurements from the messages that time-of-arrival (TOA stations in sight exchange while their positioning processes are running. This study addresses the accuracy of the TOAD algorithm in two different environments: line-of-sight (LOS and non-line-of-sight (NLOS. Simulation is used to set up a wireless network. The Gauss-Newton nonlinear least squares algorithm is used to compute the positions in both TOA and TOAD stations. Results indicate that the TOAD algorithm increases the root mean square error (RMSE of the positioning error in LOS scenarios by 10 to 20% compared with the RMSE achieved by TOA. This drop in accuracy contrasts with the results for the NLOS scenarios. The RMSE of TOAD in such scenarios is at least 10% lower than that achieved by TOA. This result is specially important since this latter scenario is the most common. Consequently, this novel technique therefore improves the scalability and integrity of TOA techniques based on RTT, making it possible for the stations to position themselves without injecting traffic and with QoS figures close and most times better than that achieved by TOA.

  7. Desiccation risk drives the spatial ecology of an invasive anuran (Rhinella marina in the Australian semi-desert.

    Directory of Open Access Journals (Sweden)

    Reid Tingley

    Full Text Available Some invasive species flourish in places that impose challenges very different from those faced in their native geographic ranges. Cane toads (Rhinella marina are native to tropical and subtropical habitats of South and Central America, but have colonised extremely arid regions over the course of their Australian invasion. We radio-tracked 44 adult cane toads at a semi-arid invasion front to investigate how this invasive anuran has managed to expand its geographic range into arid areas that lie outside of its native climatic niche. As predicted from their low physiological control over rates of evaporative water loss, toads selected diurnal shelter sites that were consistently cooler and damper (and thus, conferred lower water loss rates than nearby random sites. Desiccation risk also had a profound influence on rates of daily movement. Under wet conditions, toads that were far from water moved further between shelter sites than did conspecifics that remained close to water, presumably in an attempt to reach permanent water sources. However, this relationship was reversed under dry conditions, such that only toads that were close to permanent water bodies made substantial daily movements. Toads that were far from water bodies also travelled along straighter paths than did conspecifics that generally remained close to water. Thus, behavioural flexibility--in particular, an ability to exploit spatial and temporal heterogeneity in the availability of moist conditions--has allowed this invasive anuran to successfully colonize arid habitats in Australia. This finding illustrates that risk assessment protocols need to recognise that under some circumstances an introduced species may be able to thrive in conditions far removed from any that it experiences in its native range.

  8. All-optical adder/subtractor based on tera-hertz optical asymmetric demultiplexer

    Institute of Scientific and Technical Information of China (English)

    Dilip Kumar Gayen; Rajat Kumar Pal; Jitendra Nath Roy

    2009-01-01

    An all-optical adder/subtractor (A/S) unit with the help of terahertz optical asymmetric demultiplexer (TOAD) is proposed.Tile all-optical A/S unit with a set of all-optical full-adders and optical exclusive-ORs (XORs),can be used to perform a fast central processor unit using optical hardware components.We try to exploit the advantages of TOAD-based optical switch to design an integrated all-optical circuit which can perform binary addition and subtraction.With computer simulation results confirming the described methods,conclusions are given.

  9. Výskyt a biotopové preference obojživelníků na bývalém tankovém cvičišti u Českých Budějovic

    OpenAIRE

    NĚMEC, Stanislav

    2011-01-01

    Submitted bachelor thesis deals with biotope preferences of amphibians. Experimental part of my work was carried out at former military tank ground near České Budějovice from March until June 2010. Biotope preferences were examined at these species: European Fire-bellied Toad, European tree frog, Agile Frog and Common toad. Since the end of military activity in 1990, there has been growing ecological succession which influences each of the species. The aim of my work was to find out what fact...

  10. Amphibians of the “Cilento e Vallo di Diano” National Park (Campania, Southern Italy: updated check list, distribution and conservation notes

    Directory of Open Access Journals (Sweden)

    Antonio Romano

    2010-12-01

    Full Text Available In this study, we present the results of our field and bibliographic survey on the amphibians of the “Cilento and Vallo di Diano” National Park (Southern Italy. Two hundred and thirty three spawning sites (167 original and 66 derived from literature, and 11 amphibian species were found. Reproductive activity was recorded for Salamandra salamandra, Salamandrina terdigitata, Triturus carnifex, Lissotriton italicus, Bufo bufo, Hyla intermedia, Rana italica, Rana dalmatina and Pelophylax synkl. hispanica. The distribution record of many species is widely improved with respect to bibliographic data. Our results also suggested that preservation and restoration of small aquatic sites, in particular of the artificial ones, such as stony wells and drinking-troughs, are fundamental for an appropriate conservation management of amphibians in the “Cilento and Vallo di Diano” National Park.

  11. 华蟾素注射液多肽成分体外抗肿瘤活性研究%In vitro anti-proliferation effect of peptides from cinobufacini injection

    Institute of Scientific and Technical Information of China (English)

    吴旭; 高波; 杨健; 边宝林; 王宏洁

    2012-01-01

    Cinobufacini is an aqueous extract of Bufo bufo gargarizans Cantor dried skin, which has been widely used for cancer therapy in China. So far, its active components are still not very clear. In previous reports, bufadienolides with low-concentration were usually studied because of their anticancer effects. However, the high polarity constituents in cinobufacini are less investigated. The present study found that more than 50% contents of cinobufacini were water-soluble peptides. Then, in vitro anticancer experiments were carried out, including human stomach cancer cell lines BGC823 and MCG803, human colon cancer cell lines DLD-1 and HT-29, and human pancreatic cancer cell line MIAPACA-2. The IC50 for these cell lines model were ranged from 25-123 μg·mL-1. The results indicated that these peptides showed similar activity with cinobufacini injection. As a conclusion, this study provides a new and further understanding of anticancer components in cinobufacini injection.

  12. Local adaptation of an anuran amphibian to osmotically stressful environments

    OpenAIRE

    Gómez-Mestre, Iván; Tejedo, Miguel

    2003-01-01

    Water salinity is an intense physiological stress for amphibians. However, some species, such as Bufo calamita, breed in both brackish and freshwater environments. Because selection under environmentally stressful conditions can promote local adaptation of populations, we examined the existence of geographic variation in water salinity tolerance among B. calamita populations from either fresh or brackish water ponds in Southern Spain. Comparisons were made throughout various ontogenetic stage...

  13. Final report on effects of environmental radiation of Kori nuclear power plant on human population

    International Nuclear Information System (INIS)

    In order to clarify and protect the effects of environmental radiation according to the operation of Kori nuclear power plant on the human population, the base line survey for the human monitoring, human life habits, expected individual exposure dose, frequencies of chromosomal aberration, gene frequencies and karyotypes in amphibia, fauna, and radiation sensitivities in microorganisms which have been living around the power plant site were carried out. Kilchonri population which took for the human monitoring lie within a 2 km distance from the power plant site. Human monitoring, house and food characteristics, individual experience of x-ray exposures, human chromosome analysis and fauna were surveyed and expressed in numerical tables. Chromosome number obtained from the amphibia which were collected around the power plant area was as follows: Kaloula borealis 2N=30, Rana amurensis 2N=26, Rana dybouskii 2N=24, Rana rugosa 2N=26, Rana nigromaculata 2N=26, Rana plancyi 2N=26, Bombina orientalis 2N=24, Hyla arborea 2N=24, Bufo stejnegeri 2N=22, Bufo bufo 2N=22. (author)

  14. "mina usun sõna..." : [luuletused] / Maarja Kangro, Mart Kangur, Lauri Kitsnik jt

    Index Scriptorium Estoniae

    2007-01-01

    Sisu: "mina usun sõna..." ; Tüdruk heitis mulle silma (Silmapartii) ; "Helista siis mulle. Hoolimata sellest, mis kell ma täna magama..." ; Tärkab ; Toad ; "Tee sees on augud. Maa sees on augud..." ; "Puuk on perses. Ai-ai, valus on..." ; Päärätik ; Pliidikütt ; "Ukrainlannast põetaja..." ; Stereonurr ; "Luuletused..."

  15. Our Zoo to You

    Science.gov (United States)

    Wickless, Mimi; Brooks, David W.; Abuloum, Amjad; Mancuso, Brian; Heng-Moss, Tiffany M.; Mayo, Lois

    2003-01-01

    An innovative zoo outreach program, Our Zoo to You, places zoo animals in local classrooms for extended observation periods. With guidance and support from zoo staff, students are able to safely experience a variety of animals, including geckos, snakes, legless lizards, horned toads, ringneck doves, ferrets, hedgehogs, African brown millipedes,…

  16. Kassinurme mägedes toimusid Elendili päeva pidustused ehk Tolkieni sõprade suvelaager / Ilmar Pajumägi

    Index Scriptorium Estoniae

    Pajumägi, Ilmar

    2005-01-01

    J. R. R. Tolkieni triloogia "Sõrmuste isand" sai tänavu 50 aastaseks. Sellega seoses korraldasid muinasjutusõbrad 18.-21. aug. Jõgeva lähedal Kassinurme mägedes LARPi (Live Action Role Play). Toimusid ka mitmed teemaga seotud töötoad, õpitoad ja loengud

  17. Täpne arhitektuur : ACADIA aastakonverents Cooper Unioni arhitektuurikoolis / Veronika Valk

    Index Scriptorium Estoniae

    Valk, Veronika, 1976-

    2010-01-01

    Septembris 2010 toimunud ACADIA aastakonverentsist New Yorgis. Konverents, töötoad ja näitus pakkusid parameetrilise projekteerimise spetsialistidele üle maailma lava, kus arhitektuuri uusi suundi arutada ja oma praktika üle mõtteid vahetada

  18. Effect of atrazine and fenitrothion at no-observed-effect-levels (NOEL) on amphibian and mammalian corticosterone-binding-globulin (CBG).

    Science.gov (United States)

    Hernández, Sandra E; Sernia, Conrad; Bradley, Adrian J

    2014-11-01

    This study determines the effect of atrazine and fenitrothion no-observed-effect-levels (NOEL) on the binding of corticosterone (B) to corticosterone-binding-globulin (CBG) in an amphibian and a mammal. Plasma from five cane toads and five Wistar rats was exposed to atrazine and fenitrothion at the NOEL approved for Australian fresh water residues and by the World Health Organization (WHO). The concentration required to displace 50% (IC50) of B binding to CBG was determined by a competitive microdialysis protein assay. Competition studies showed that both atrazine and fenitrothion at NOEL are able to compete with B for CBG binding sites in toad and rat plasma. The IC50 levels for atrazine in toads and rats were 0.004 nmol/l and 0.09 nmol/l respectively. In the case of fenitrothion the IC50 level found in toads was 0.007 nmol/l, and 0.025 nmol/l in rats. Plasma dilution curves showed parallelism with the curve of B, demonstrating that these agro-chemicals are competitively inhibiting binding to CBG. The displacement of B by atrazine and fenitrothion would affect the total:free ratio of B and consequently disrupt the normal stress response. This is the first time that the potential disruptive effect of atrazine and fenitrothion on B-CBG interaction at the NOELs has been demonstrated in amphibian and mammalian models.

  19. What Do Amphibians Have to Offer?: Students Monitor and Map Amphibians in Local Pond Habitats

    Science.gov (United States)

    Eareckson, Lee Anne

    2002-01-01

    Students value participation in meaningful research. They feel empowered when they effect positive change in their communities. They also have a strong affinity for frogs and toads, although they vehemently deny this at the start of the school year. In addition, most students recognize the value of using computer technology to solve world…

  20. All about Amphibians. Animal Life for Children. [Videotape].

    Science.gov (United States)

    2000

    This videotape teaches children about their favorite amphibious creatures, as well as amphibians' nearest cousins--toads, newts, and salamanders. Young students discover how these amazing creatures can live both in and out of water, learn about the amphibious life cycle, and compare the differences between amphibians and reptiles. This videotape…

  1. Microelectronic neural bridge for signal regeneration and function rebuilding over two separate nerves

    Science.gov (United States)

    Xiaoyan, Shen; Zhigong, Wang; Xiaoying, Lü; Shushan, Xie; Zonghao, Huang

    2011-06-01

    According to the feature of neural signals, a micro-electronic neural bridge (MENB) has been designed. It consists of two electrode arrays for neural signal detection and functional electrical stimulation (FES), and a microelectronic circuit for signal amplifying, processing, and FES driving. The core of the system is realized in 0.5-μm CMOS technology and used in animal experiments. A special experimental strategy has been designed to demonstrate the feasibility of the system. With the help of the MENB, the withdrawal reflex function of the left/right leg of one spinal toad has been rebuilt in the corresponding leg of another spinal toad. According to the coherence analysis between the source and regenerated neural signals, the controlled spinal toad's sciatic nerve signal is delayed by 0.72 ms in relation to the sciatic nerve signal of the source spinal toad and the cross-correlation function reaches a value of 0.73. This shows that the regenerated signal is correlated with the source sciatic signal significantly and the neural activities involved in reflex function have been regenerated. The experiment demonstrates that the MENB is useful in rebuilding the neural function between nerves of different bodies.

  2. Microelectronic neural bridge for signal regeneration and function rebuilding over two separate nerves*

    Institute of Scientific and Technical Information of China (English)

    Shen Xiaoyan; Wang Zhigong; Lü Xiaoying; Xie Shushan; Huang Zonghao

    2011-01-01

    According to the feature of neural signals, a micro-electronic neural bridge (MENB) has been designed.It consists of two electrode arrays for neural signal detection and functional electrical stimulation (FES), and a microelectronic circuit for signal amplifying, processing, and FES driving. The core of the system is realized in 0.5-μm CMOS technology and used in animal experiments. A special experimental strategy has been designed to demonstrate the feasibility of the system. With the help of the MENB, the withdrawal reflex function of the left/right leg of one spinal toad has been rebuilt in the corresponding leg of another spinal toad. According to the coherence analysis between the source and regenerated neural signals, the controlled spinal toad's sciatic nerve signal is delayed by 0.72 ms in relation to the sciatic nerve signal of the source spinal toad and the cross-correlation function reaches a value of 0.73. This shows that the regenerated signal is correlated with the source sciatic signal significantly and the neural activities involved in reflex function have been regenerated. The experiment demonstrates that the MENB is useful in rebuilding the neural function between nerves of different bodies.

  3. Microelectronic neural bridge for signal regeneration and function rebuilding over two separate nerves

    Energy Technology Data Exchange (ETDEWEB)

    Shen Xiaoyan; Wang Zhigong; Xie Shushan; Huang Zonghao [Institute of RF- and OE-ICs, Southeast University, Nanjing 210096 (China); Lue Xiaoying, E-mail: zgwang@seu.edu.cn [Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096 (China)

    2011-06-15

    According to the feature of neural signals, a micro-electronic neural bridge (MENB) has been designed. It consists of two electrode arrays for neural signal detection and functional electrical stimulation (FES), and a microelectronic circuit for signal amplifying, processing, and FES driving. The core of the system is realized in 0.5-{mu}m CMOS technology and used in animal experiments. A special experimental strategy has been designed to demonstrate the feasibility of the system. With the help of the MENB, the withdrawal reflex function of the left/right leg of one spinal toad has been rebuilt in the corresponding leg of another spinal toad. According to the coherence analysis between the source and regenerated neural signals, the controlled spinal toad's sciatic nerve signal is delayed by 0.72 ms in relation to the sciatic nerve signal of the source spinal toad and the cross-correlation function reaches a value of 0.73. This shows that the regenerated signal is correlated with the source sciatic signal significantly and the neural activities involved in reflex function have been regenerated. The experiment demonstrates that the MENB is useful in rebuilding the neural function between nerves of different bodies. (semiconductor integrated circuits)

  4. Responding to Amphibian Loss

    NARCIS (Netherlands)

    J.R. Mendelson III; K.R. Lips; R.W. Gagliardo; G.B. Rabb; J.P. Collins; J.E. Diffendorfer; P. Daszak; R. Ibáñez D.; K.C. Zippel; D.P. Lawson; K.M. Wright; S.N. Stuart; C. Gascon; H.R. da Silva; P.A. Burrowes; R.L. Joglar; E. La Marca; S. Lötters; L.H. du Preez; C. Weldon; A. Hyatt; J.V. Rodriguez-Mahecha; S. Hunt; H. Robertson; B. Lock; C.J. Raxworthy; D.R. Frost; R.C. Lacy; R.A. Alford; J.A. Campbell; G. Parra-Olea; F. Bolaños; J.J. Calvo Domingo; T. Halliday; J.B. Murphy; M.H. Wake; L.A. Coloma; S.L. Kuzmin; M.S. Price; K.M. Howell; M. Lau; R. Pethiyagoda; M. Boone; M.J. Lannoo; A.R. Blaustein; A. Dobson; R.A. Griffiths; M.L. Crump; D.B. Wake; E.D. Brodie Jr

    2006-01-01

    In their Policy Forum "Confronting amphibian declines and extinctions" (7 July, p. 48), J. R. Mendelson III and colleagues offer a strategy for "stopping" the widespread losses of frogs, toads, and salamanders. Disease research and captive breeding figure prominently in their call for action.

  5. Vertebral number is highly evolvable in salamanders and newts (family Salamandridae) and variably associated with climatic parameters

    NARCIS (Netherlands)

    Arntzen, J.W.; Beukema, W.; Galis, F.; Ivanović, A.

    2015-01-01

    In vertebrates, the relative proportion of the number of trunk and caudal vertebrae is an important determinant of body shape. While among amphibians frogs and toads show low variation in vertebrae numbers, in salamanders the numbers of trunk and caudal vertebrae vary widely, giving rise to phenotyp

  6. MRI zoo

    DEFF Research Database (Denmark)

    Laustsen, Christoffer

    The basic idea was to use MRI to produce a sequence of 3D gray scale image slices of various animals, subsequentlyimaged with a clinical CT system. For this purpose, these animals were used: toad, lungfish, python snake and a horseshoe crab. Each animal was sacrificed according to standard proced...

  7. 76 FR 78805 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-Trent 800 Series Turbofan Engines

    Science.gov (United States)

    2011-12-20

    ... Register on August 22, 2011 (76 FR 52288). That NPRM proposed to correct an unsafe condition for the.... American also asserted that the estimate in the NPRM (76 FR 52288, August 22, 2011) of labor hours to...-AD685, which are referenced in the NPRM (76 FR 52288), do not include inspection criteria for the...

  8. Membrane interaction and antibacterial properties of two mildly cationic peptide diastereomers, bombinins H2 and H4, isolated from Bombina skin

    NARCIS (Netherlands)

    C. Coccia; A.C. Rinaldi; V. Luca; D. Barra; A. Bozzi; A. Di Giulio; E.C.I. Veerman; M.L. Mangoni

    2011-01-01

    Bombinins H are mildly cationic antimicrobial peptides isolated from the skin of the anuran genus Bombina, the fire-bellied toad. Some members of this peptide family coexist in skin secretions as diastereomers in which a single D-amino acid (alloisoleucine or leucine) is incorporated as a result of

  9. Feleucins: Novel Bombinin Precursor-Encoded Nonapeptide Amides from the Skin Secretion of Bombina variegata

    Directory of Open Access Journals (Sweden)

    Bing Bai

    2014-01-01

    Full Text Available The first amphibian skin antimicrobial peptide (AMP to be identified was named bombinin, reflecting its origin from the skin of the European yellow-bellied toad (Bombina variegata. Bombinins and their related peptides, the bombinin Hs, were subsequently reported from other bombinid toads. Molecular cloning of bombinin-encoding cDNAs from skin found that bombinins and bombinin Hs were coencoded on the same precursor proteins. Here, we report the molecular cloning of two novel cDNAs from a skin secretion-derived cDNA library of B. variegata whose open-reading frames each encode a novel bombinin (GIGGALLNVGKVALKGLAKGLAEHFANamide and a C-terminally located single copy of a novel nonapeptide (FLGLLGGLLamide or FLGLIGSLLamide. These novel nonapeptides were named feleucin-BV1 and feleucin-BV2, respectively. The novel bombinin exhibited 89% identity to homologues from the toads, B. microdeladigitora and B. maxima. The feleucins exhibited no identity with any amphibian AMP archived in databases. Synthetic feleucins exhibited a weak activity against Staphylococcus aureus (128–256 mg/L but feleucin-BV1 exhibited a synergistic action with the novel bombinin. The present report clearly demonstrates that the skin secretions of bombinid toads continue to represent a source of peptides of novel structure that could provide templates for the design of therapeutics.

  10. Plasticity in the melanotrope neuroendocrine interface of Xenopus laevis

    NARCIS (Netherlands)

    Jenks, B.G.; Kidane, A.H.; Scheenen, W.J.; Roubos, E.W.

    2007-01-01

    Melanotrope cells of the amphibian pituitary pars intermedia produce alpha-melanophore-stimulating hormone (alpha-MSH), a peptide which causes skin darkening during adaptation to a dark background. The secretory activity of the melanotrope of the South African clawed toad Xenopus laevis is regulated

  11. Myths.

    Science.gov (United States)

    Wheat, Maxwell Corydon, Jr.

    1982-01-01

    Deals with various myths about animals and plants. Discusses bats (not blind), toads (do not cause warts), dragonflies (will not sew up your mouth), horseshoe crabs (will not sting with their tails), owls (not so smart), and goldenrod (does not cause hayfever). (MH)

  12. Historical biogeography of Western Palaearctic pelobatid and pelodytid frogs: a molecular phylogenetic perspective

    NARCIS (Netherlands)

    Veith, M.; Fromhage, L.; Kosuch, J.; Vences, M.

    2006-01-01

    Spadefoot toads (Pelobates) and Parsley frogs (Pelodytes) are an enigmatic group of Western Palaearctic anurans. In the genus Pelobates, a fossorial lifestyle has enforced a conserved bauplan that masks their intraspecific evolutionary history. We used partial sequences of the mitochondrial 16S and

  13. New Host and Distribution Records of the Leech Placobdella sophieaeOceguera-Figueroa et al., 2010 (Hirudinida: Glossiphoniidae)

    Science.gov (United States)

    Moser, William E.; Bowerman, Jay; Hovingh, Peter; Pearl, Christopher A.; Oceguera-Figueroa, Alajandro

    2014-01-01

    Placobdella sophieae Oceguera-Figueroa et al., 2010 (Hirudinida: Glossiphoniidae) is reported from Oregon, California, and British Columbia for the first time. New hosts reported for P. sophieae include Taricha granulosa (rough-skinned newt), Rana pretiosa (Oregon spotted frog), and Anaxyrus boreas (western toad). Placobdella sophieae exhibits relatively low host specificity and all amphibians occurring in the Pacific Northwest are potential hosts.

  14. Further report of the occurrence of tetrodotoxin in Atelopus species (family: Bufonidae).

    Science.gov (United States)

    Mebs, D; Yotsu-Yamashita, M; Yasumoto, T; Lötters, S; Schlüter, A

    1995-02-01

    In alcoholic extracts from museum samples of the toads Atelopus subornatus and A. peruensis tetrodotoxin and its analogues, 4-epitetrodotoxin and 4,9-anhydrotetrodotoxin were detected by fluorometric HPLC analysis, extending the list of amphibians containing this toxin. However, the toxin was not detected in samples of Melanophryniscus stelzneri, Dendrophryniscus minutus and Oreophrynella sp. PMID:7597728

  15. Incidencia de los atropellos sobre la fauna vertebrada en el Valle de El Paular. LIC "Cuenca del río Lozoya y Sierra Norte"

    Directory of Open Access Journals (Sweden)

    ESPINOSA, A., SERRANO, J.A., MONTORI, A.

    2012-01-01

    Full Text Available Las carreteras son uno de los agentes antrópicos de cambio más importantes. Son uno de los más relevantes agentes de fragmentación de hábitat, transformación de los sistemas naturales y actúan como un depredador inespecífico sobre la fauna. Varios estudios han demostrado que son la principal causa de mortalidad de anfibios, como es el caso del sapo común Bufo bufo (Linnaeus, 1758 en España. En un estudio previo realizado en la zona se puso de manifiesto que la mayor incidencia de los atropellos se producía sobre dos especies: Bufo calamita Laurenti, 1768 y Bufo bufo. Para analizar la situación actual y ampliar el área de estudio se seleccionaron 13 tramos de 1 km en las carreteras M-604 y M-611 localizadas en el LIC del Alto Lozoya (Sistema Central, Península Ibérica. Cada segmento prospectado se recorrió a pie en ambos sentidos tres veces al mes, durante dos años, desde marzo de 2009 (934 muestreos. Los transectos se caracterizaron considerando las variables: altitud de inicio y final, cobertura arbórea (para una franja de 20 m a ambos lados de la carretera, grado de humanización (muy bajo, bajo, medio y vegetación dominante. Las visitas a los tramos se realizaron con un intervalo promedio de 9 días, tiempo suficiente para que no existieran observaciones repetidas. Además, los ejemplares atropellados detectados eran retirados de la calzada cuando esto era posible. Se han registrado un total de 632 vertebrados muertos en la calzada que se distribuyen por grupos en 123 anfibios, 160 reptiles, 191 aves y 80 mamíferos de 4, 14, 26 y 12 especies distintas, respectivamente. No se han encontrado diferencias en el número de atropellos según el día de la semana, pero sí existen claras diferencias en la distribución de los atropellos a lo largo del año. Sólo dos variables ambientales muestran diferencias significativas según el grupo: el grado de humanización y el hábitat. Sin embargo, el test PostHoc de Bonferroni indica

  16. Atlas de distribución y estado de conservación de los Anfibios de la Comunidad de Madrid

    Directory of Open Access Journals (Sweden)

    Martínez-Solano, I.

    2006-05-01

    Full Text Available Successful management and conservation planning depend upon the availability, integration and updating of information provided by different disciplines. This paper compiles relevant information for the conservation of amphibians in Comunidad de Madrid (Spain. We obtained chorological information from 1384 sampling localities throughout the region of Madrid, and reviewed relevant scientific literature for the management of amphibian populations in this area. We found at least one amphibian species in 70,3% of sampled localities. Results are illustrated in distribution maps of all 18 species found: Salamandra salamandra, Pleurodeles waltl, Mesotriton alpestris, Lissotriton boscai, Triturus marmoratus, Triturus pygmaeus, Alytes obstetricans, Alytes cisternasii, Discoglossus galganoi, Discoglossus jeanneae, Pelobates cultripes, Pelodytes punctatus, Hyla arborea, Hyla meridionalis, Bufo bufo, Bufo calamita, Rana iberica and Rana perezi. Distribution maps are presented in five-kilometer side UTM grids cells. We compare and integrate our results with previous studies and outline groups of populations representing independent management units, for which we propose risk categories according to the criteria established by the International Union for the Conservation of Nature (IUCN at the regional level. Finally, we point out the main threats for the survival of amphibian populations and discuss possible actions to improve their conservation status.

    La planificación de estrategias de gestión y conservación eficaces depende de la disponibilidad, integración y actualización de información procedente de diversas disciplinas. En este trabajo se recopila información relevante para la conservación de los anfibios de la Comunidad de Madrid. Hemos obtenido información corológica de un total de 1384 puntos de muestreo repartidos por toda la geografía madrileña y revisado la literatura científica de interés para la gestión de las

  17. Bibliographic Studies on the Bufonis Venenum

    Directory of Open Access Journals (Sweden)

    Kye-Sung Kang

    2001-06-01

    Full Text Available Objectives : Through the literatures on the effets of Bufonis Venenum, we are finding out the clinical possibility and revealing the more effective to intractable diseases. Methods : We investigated the literatures of Oriental Medicine and experimental reports about Bufonis Venenum. Results : 1. Bufonis Venenum is made of bufonidae bufo bufo gargarizans cantor or bufo melanostictus schneider of white serum which secreted from parotid gland or dermato gland, and it is dried for using. 2. In oriental medicine, Bufonis Venenum has been mainly used on the tumors, cacanthrax and dermatic disease, and then it has been clinically used on infantile athrepsia, tetanus, sore throat, toothache, and so on. 3. The pharmacological effects of Bufonis Venenum are cardiotonic, respiration stimulation, depressor or vasopressor, topical anesthcsia, hallucination, striped muscle stimulation, antiasthmatic, antibacterial, antiinflammatory, anticancer, diuretic, immuno effects, etc. 4. Bufonis Venenum is largely divided in ether binding steroid compound, hydroxyl steroid compound, carboxyl or aldehyde steroid compound, indole compound, and adrenaline, cholesterole, etc. 5. Symptoms of Bufonis Venenum poisoning in digestive system are vommitig, abdominal pain, diarrhea, dehydration, in circulatory system are palpitation, shock, bradycardia, in nervous system are vertigo, somnolentia, muscle-tendon reflex weakness, and critical conditions to tissue necrosis and heart attack. 6. Ways to treat Bufonis Venenum poisoning include gastric irrigation with 0.20.5% potassium permanganate fluid and atropine 0.5~1.0mg subcutaneous injection. From the chinese book of Bon Cho Gang Moke(本草綱目, if white serum of Bufonis Venenum enter the eyes, it happens the edema and pain. And then washed the eyes by juice of Lithospermi Radix(紫草 that the edema is removed. Conclusions and Discussion : The results from above literary studies show that prescriptions and Aqua-acupuncture of

  18. Effects of Roads on Amphibian Populations

    DEFF Research Database (Denmark)

    Hels, T.

    to have experienced the wonders of early summer sunrises in the field - and the joy of thawing out frozen fingers after hours of field work around freezing point. Amphibian populations are declining. This worrying fact is what has initiated this work. Some fifty years ago, the life history of frogs...... and toads was common knowledge to everybody due to personal experience: amphibians were abundant. Noisy and innumerable in spring when reproducing, silent and even more abundant in late summer with both adults and metamorphs leaving the breeding ponds. Today, experiencing frogs and toads is an event......, something to talk about. Fortunately, amphibians are still numerous in certain places and hopefully, we will get to a point when we know enough about the declines and their backgrounds to bring the decline to an end. It is my hope that results of this work will add a piece to the puzzle. This work...

  19. Evolution of dispersal and life history interact to drive accelerating spread of an invasive species.

    Science.gov (United States)

    Perkins, T Alex; Phillips, Benjamin L; Baskett, Marissa L; Hastings, Alan

    2013-08-01

    Populations on the edge of an expanding range are subject to unique evolutionary pressures acting on their life-history and dispersal traits. Empirical evidence and theory suggest that traits there can evolve rapidly enough to interact with ecological dynamics, potentially giving rise to accelerating spread. Nevertheless, which of several evolutionary mechanisms drive this interaction between evolution and spread remains an open question. We propose an integrated theoretical framework for partitioning the contributions of different evolutionary mechanisms to accelerating spread, and we apply this model to invasive cane toads in northern Australia. In doing so, we identify a previously unrecognised evolutionary process that involves an interaction between life-history and dispersal evolution during range shift. In roughly equal parts, life-history evolution, dispersal evolution and their interaction led to a doubling of distance spread by cane toads in our model, highlighting the potential importance of multiple evolutionary processes in the dynamics of range expansion.

  20. Choosy Cannibals Preferentially Consume Siblings with Relatively Low Fitness Prospects.

    Science.gov (United States)

    Dugas, Matthew B; McCormack, Larkin; Gadau, Alice; Martin, Ryan A

    2016-07-01

    When an individual can selfishly cannibalize a relative or altruistically set it free, the benefits of altruism will be positively associated with the relative's fitness prospects (the benefits it receives from altruism). We tested the prediction that altruism should be preferentially directed toward high-quality relatives using larvae of the New Mexican spadefoot toad (Spea multiplicata), a species in which tadpoles plastically express omnivore and carnivore ecomorphs. In a no-choice design, we presented carnivores with sibling or nonsibling omnivores varying in developmental stage, which is positively associated with survival in this toad's ephemeral larval environment. There was a significant interaction between relatedness and developmental stage on the probability of cannibalism: carnivores were overall more likely to cannibalize less developed omnivores, but this effect was exaggerated when the potential victim was a sibling. This evidence that altruists favor relatives with high fitness prospects highlights the numerous factors shaping altruism's payoffs. PMID:27322127

  1. Amphibian monitoring in the Atchafalaya Basin

    Science.gov (United States)

    Waddle, Hardin

    2011-01-01

    Amphibians are a diverse group of animals that includes frogs, toads, and salamanders. They are adapted to living in a variety of habitats, but most require water for at least one life stage. Amphibians have recently become a worldwide conservation concern because of declines and extinctions even in remote protected areas previously thought to be safe from the pressures of habitat loss and degradation. Amphibians are an important part of ecosystem dynamics because they can be quite abundant and serve both as a predator of smaller organisms and as prey to a suite of vertebrate predators. Their permeable skin and aquatic life history also make them useful as indicators of ecosystem health. Since 2002, the U.S. Geological Survey has been studying the frog and toad species inhabiting the Atchafalaya Basin to monitor for population declines and to better understand how the species are potentially affected by disease, environmental contaminants, and climate change.

  2. Cryptosporidia: epicellular parasites embraced by the host cell membrane.

    Science.gov (United States)

    Valigurová, Andrea; Jirků, Miloslav; Koudela, Bretislav; Gelnar, Milan; Modrý, David; Slapeta, Jan

    2008-07-01

    The ultrastructure of two gastric cryptosporidia, Cryptosporidium muris from experimentally infected rodents (Mastomys natalensis) and Cryptosporidium sp. 'toad' from naturally infected toads (Duttaphrynus melanostictus), was studied using electron microscopy. Observations presented herein allowed us to map ultrastructural aspects of the cryptosporidian invasion process and the origin of a parasitophorous sac. Invading parasites attach to the host cell, followed by gradual envelopment, with the host's cell membrane folds, eventually forming the parasitophorous sac. Cryptosporidian developmental stages remain epicellular during the entire life cycle. The parasite development is illustrated in detail using high resolution field emission scanning electron microscopy. This provides a new insight into the ultrastructural detail of host-parasite interactions and species-specific differences manifested in frequency of detachment of the parasitophorous sac, radial folds of the parasitophorous sac and stem-formation of the parasitised host cell. PMID:18158154

  3. Studies of annual and seasonal variations in four species of reptiles and amphibians at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, E.I.; Haarmann, T.; Keller, D.C.; Foxx, T.

    1998-11-01

    Baseline studies of reptiles and amphibians of the Pajarito wetlands at Los Alamos National Laboratory have been conducted by the Ecology group since 1990. With the gathered data from 1990--1997 (excluding 1992), they plan to determine if patterns can be found in the annual and seasonal population changes of four species of reptiles and amphibians over the past seven years. The four species studied are the Woodhouse toad, the western chorus frog, the many-linked skink, and the plateau striped whiptail lizard. Statistical analysis results show that significant changes occurred on a seasonal basis for the western chorus frog and the many-lined skink. Results indicate a significant difference in the annual population of the Woodhouse toad.

  4. Información proporcionada por cazadores sobre la fauna de Vadocondes (Burgos) el 13 de noviembre de 1953

    OpenAIRE

    Valverde Gómez, José Antonio, 1926-2003

    2008-01-01

    Información proporcionada al autor por cazadores, sobre la fauna de Vadocondes (Burgos), a 13 de noviembre de 1953, que incluye a los siguientes anfibios: Alytes sp. (Sapo partero), Bufo sp. (Sapo) y "Molge sp." (puede referirse a Triturus marmoratus o a Pleurodeles waltl), los siguientes mamíferos: Ardilla (pudiendo ser, Sciurus vulgaris o Atlantoxerus getulus), Canis lupus (Lobo), Erizo (pudiendo ser Erinaceus europaeus o Atelerix algirus), Felis silvestris (Gato montés), Lirón (pudiendo se...

  5. Salida de campo a Villarmentero de Esgueva (Valladolid) el 18 de julio de 1956

    OpenAIRE

    Valverde Gómez, José Antonio, 1926-2003

    2008-01-01

    Salida de campo a Villarmentero de Esgueva (Valladolid) el 18 de julio de 1956, de la que se anotaron observaciones, agrupando las especies por hábitats, sobre el anfibio Epidalea calamita (Sapo corredor, llamado Bufo calamita por el autor), el reptil Natrix maura (Culebra viperina, llamada Tropidonotus viperinus por el autor), los siguientes mamíferos: Martes foina (Garduña), Mustela nivalis (Comadreja) y Mustela putorius (Turón), y las siguientes aves: Alectoris sp. (Perdiz), Calandrella sp...

  6. Electrophoretic pattern of blood serum proteins of some of the vertebrates of Pakistan

    International Nuclear Information System (INIS)

    The electrophoretic pattern of blood serum proteins of some of the common fishes e.g. Catla catla, Cirrhina mrigala, Channa punctatus, Channa marulius, Wallago attu, Heterop-neustes fossilis; amphibia e.g., Rana tigrina, Rana cyanophlyctis, Bufo melanostictus; reptiles e.g. Varanus bengalensis, Uromastix hardwickii; birds e.g. Columba livia, Gallus domesticus, Passer domestica, Anas platyrhynchos; and mammals e.g. Homo sapiens, Mus musculus, Lepus cuniculus have been described. The mobility of proteins of blood sera has been studied over cellulose acetate paper and then a comparative pattern analysed

  7. Dynamic stability of communities of amphibians in short-term-flooded forest ecosystems

    Directory of Open Access Journals (Sweden)

    O. V. Zhukov

    2015-09-01

    Full Text Available The estimation of stability of amphibian populations on the basis of data of population dynamics is given. The paper shows an attempt to estimate the direction of dynamic changes of amphibian populations, and defines the rate of the system deviation from the stationary state due to possible influence of the environmental factors by using concepts such as reactivity, degree of reactivity and flexibility of the system when using their indexes. It is found that populations of amphibians are quite stable with regard to quantifying these species. Characteristic feature is the elasticity of the system. It is confirmed by the elasticity of the system species Bufo bufo (Linnaeus, 1758. TypePelobates fuscus (Laurenti, 1768 is defined as a factor of stability of the system in quantitative terms. Dependenceof dynamics of the population on its size is established using the regression equation. Dynamics of groups depends on the action of possible predictors in response to which the population of B. bufo is not changed. The ecosystem is characterized as a place of interaction between biotic factors and factors of abiotic origin, which are due to the external action. Internal factor of the ecosystem stability is the influence of some amphibian populations on the other ones. The system features sustainable and relatively stable number of B. bufo, which does not affect the level of its stability. Stationary state of the grouping is unstable due to dynamic matrix, which describes the behavior of the group in the vicinity of the first stationary state. The second steady state is stableone, and the system returns to the stationary state with the help of wave-like dynamics. On the basis of our study it is established that the number of groups of amphibians remains stable, the systems behave differently, and dynamics of their return to the stationary state is elastic or reactive one. Еcosystems within lime-ash oak forests in the Central floodplain of the Samarariver

  8. Widespread disruptive selection in the wild is associated with intense resource competition

    OpenAIRE

    Martin Ryan A; Pfennig David W

    2012-01-01

    Abstract Background Disruptive selection has been documented in a growing number of natural populations. Yet, its prevalence within individual systems remains unclear. Furthermore, few studies have sought to identify the ecological factors that promote disruptive selection in the wild. To address these issues, we surveyed 15 populations of Mexican spadefoot toad tadpoles, Spea multiplicata, and measured the prevalence of disruptive selection acting on resource-use phenotypes. We also evaluate...

  9. Corticotropin-releasing factor (CRF)-like immunoreactivity in the vertebrate endocrine pancreas.

    OpenAIRE

    Petrusz, P; Merchenthaler, I; Maderdrut, J L; Vigh, S; Schally, A V

    1983-01-01

    The light microscopic immunocytochemical localization of corticotropin-releasing factor (CRF) is described in the endocrine pancreas of several species representing the major classes of vertebrates: fishes (channel catfish, Ictalurus punctatus), amphibians (African clawed toad, Xenopus laevis), reptiles (chameleon, Anolis carolinensis), birds (chicken, Gallus domesticus), and several mammals (rat, mouse, cat, rhesus monkey, and man). The CRF-containing cells are scattered over the entire isle...

  10. Clutch size in wild populations of Alytes muletensis

    OpenAIRE

    Samuel Pinya; Valentín Pérez-Mellado

    2014-01-01

    Clutch size of genus Alytes presents strong inter- and intra-specific variability. The Mallorcan midwife toad (A. muletensis) is a threatened endemism of the island of Mallorca (Spain), and has the smallest clutch size of the genus. Most of the previously published clutch size information was obtained from animals breeding in captivity. In this study we analysed a large number of clutches from wild populations, and we compared their size (number of eggs) with previously published data from bo...

  11. Bent's Old Fort: Amphibians and Reptiles

    Science.gov (United States)

    Muths, E.

    2008-01-01

    Bent's Old Fort National Historic Site sits along the Arkansas River in the semi-desert prairie of southeastern Colorado. The USGS provided assistance in designing surveys to assess the variety of herpetofauna (amphibians and reptiles) resident at this site. This brochure is the results of those efforts and provides visitors with information on what frogs, toads, snakes and salamanders might be seen and heard at Bent's Old Fort.

  12. Venomous and Poisonous Australian Animals of Veterinary Importance: A Rich Source of Novel Therapeutics

    OpenAIRE

    Hardy, Margaret C.; Jonathon Cochrane; Allavena, Rachel E.

    2014-01-01

    Envenomation and poisoning by terrestrial animals (both vertebrate and invertebrate) are a significant economic problem and health risk for domestic animals in Australia. Australian snakes are some of the most venomous animals in the world and bees, wasps, ants, paralysis ticks, and cane toads are also present as part of the venomous and poisonous fauna. The diagnosis and treatment of envenomation or poisoning in animals is a challenge and can be a traumatic and expensive process for owners. ...

  13. Injuries, envenomations and stings from exotic pets

    OpenAIRE

    Warwick, Clifford; Steedman, Catrina

    2012-01-01

    A variety of exotic vertebrate and invertebrate species are kept as ‘pets’ including fishes, amphibians (for example, frogs and toads), reptiles (turtles, crocodiles, lizards and snakes), birds, mammals (for example, primates, civets, and lions), and invertebrates (for example spiders, scorpions, and centipedes), and ownership of some of these animals is rising. Data for 2009–2011 suggest that the number of homes with reptiles rose by approximately 12.5%. Recent surveys, including only some o...

  14. Historical biogeography of Western Palearctic pelobatid and pelodytid frogs: a molecular phylogenetic perspective

    OpenAIRE

    Veith, M.; Fromhage, L.; Kosuch, J.; Vences, M.

    2006-01-01

    Abstract Spadefoot toads (Pelobates) and Parsley frogs (Pelodytes) are an enigmatic group of Western Palaearctic anurans. In the genus Pelobates, a fossorial lifestyle has enforced a conserved bauplan that masks their intraspecific evolutionary history. We used partial sequences of the mitochondrial 16S and 12S rRNA genes to infer a paleobiogeographic scenario of speciation events in these two anuran genera. Based on two alternative, mutually exclusive calibrations of the Iberian-African spli...

  15. Developmental reversal in neuropeptide Y action on feeding in an amphibian.

    Science.gov (United States)

    Crespi, Erica J; Denver, Robert J

    2012-07-01

    Neuropeptide Y (NPY) is expressed in the hypothalamus where it exerts orexigenic actions within the feeding control circuit. While NPY stimulates feeding in juvenile and adult animals, it is not known whether NPY influences food intake at earlier life stages. We investigated a role for NPY in regulating feeding at two stages of the life cycle of an amphibian, the Western spadefoot toad Spea hammondii. We administered NPY by intracerebroventricular (i.c.v.) injection to juvenile toads or prometamorphic tadpoles, and monitored locomotion, feeding behavior and/or food intake. Injection of NPY (20 or 200 ng/g BW) into juvenile toads decreased the latency to, and increased the number of strikes at prey, and the number of crickets eaten compared to uninjected or vehicle-injected controls. By contrast, injection of NPY (0.02-20 ng/g BW) into prometamorphic tadpoles caused a dose-dependent decrease in time spent foraging compared to controls. Blocking NPY signaling in the prometamorphic tadpole brain by i.c.v. injection of a general NPY receptor antagonist increased foraging, and partly blocked the action of exogenous NPY on foraging. Taken together, our findings show a developmental reversal in NPY actions on feeding in an amphibian, with the peptide having a characteristic orexigenic action in the juvenile toad, but an inhibitory action on foraging in the prometamorphic tadpole. The anorexigenic action of NPY in the tadpole correlates with a decrease in feeding that occurs at metamorphic climax when the tadpole's gut and cranium remodels for the transition to a carnivorous diet.

  16. Evidence for Concerted Effects of Aldosterone On a Target Sodium-transporting Epithelium

    OpenAIRE

    BEAUWENS, R; Crabbé, J.

    1983-01-01

    The sodium-transporting activity of toad skin is stimulated in vitro with aldosterone in the absence of energy-providing substrate; it can be stimulated further upon addition of glucose after prolonged (overnight) incubation. The magnifying effect exerted by glucose in these conditions could be blocked by inhibitors of ribonucleic acid and protein biosynthesis. In addition, exposure to cycloheximide prevented the increase in thermodynamic affinity resulting from aldosterone treatment. A synth...

  17. Effects of Changing Density and Food Level on Metamorphosis of a Desert Amphibian, Scaphiopus Couchii

    OpenAIRE

    Newman, R.A.

    1994-01-01

    Amphibians that breed in temporary ponds provide a good opportunity to study the ecological and evolutionary consequences of environmental variability. Ephemeral aquatic habitats provide larval amphibians a transient and highly variable opportunity for growth. In the desert ponds used by Couch's spadefoot toad (Scaphiopus couchii), tadpole density varies considerably among ponds and often increases within a pond as it dries. Models of optimal size and timing of metamorphosis predict that, rel...

  18. Solar Radiation Alters Toxicity of Carbofuran: Evidence from Empirical Trials with Duttaphyrnus melanostictus

    OpenAIRE

    M. R. Wijesinghe; B.A.D.M.C. Jayatillake; W. D. Ratnassoriya

    2011-01-01

    In the present study we investigated the potential of natural solar radiation to alter the toxicity of a commonly used carbamate pesticide, carbofuran, on tadpoles of the Common Asian Toad Duttaphrynus melanostictus. A single exposure trial was conducted over 96 hrs with three concentrations (150, 250 and 500 µgl-1) of photo-irradiated and non-irradiated carbofuran. Results show that photo-irradiation markedly reduced the toxicity of carbofuran as evident by its effects on three end points, i...

  19. Consequences of Physical Disturbance by Tadpoles and Snails on Chironomid Larvae

    OpenAIRE

    Gargi Pal; Gautam Aditya; Niladri Hazra

    2014-01-01

    Indirect interactions among community members impact on organisms. The effects of two snails, banded pond snail, Bellamya bengalensis (Lamarck), and Red-rimmed melania, Melanoides tuberculata (Müller), and tadpoles of Asian common toad, Duttaphrynus melanostictus (Schneider), on nonbiting midge larvae, Chironomus striatipennis Kieffer, were observed in experimental microcosm. Decrease in tube number and tube length of midge larvae was observed compared to control condition due to introduction...

  20. Chlorpyrifos-induced Histopathological Alterations in Duttaphrynus melanostictus (Schneider 1799) Tadpoles: Evidence from Empirical Trials

    OpenAIRE

    M. G. D. K. Bandara; M. R. Wijesinghe; W D Ratnasooriya; A. A. H. Priyani

    2012-01-01

    This paper reports the histopathological responses of the gill, liver and tail muscle tissues in tadpoles of the Asian Common Toad Duttaphrynus melanostictus (Schneider, 1799) exposed to chlorpyrifos a common organophosphorus pesticide. Tadpoles of Gosner stages 24-26 were continuously exposed to low, mid and high (500, 1000 and 1500 µgl–1) concentrations of chlorpyrifos for two weeks. Histological alterations in the tissues of the surviving larvae were microscopically examined both at the en...