Sample records for bufonid toads melanophryniscus

  1. A new species of Melanophryniscus (Anura, Bufonidae from Uruguay Una nueva especie de Melanophryniscus (Anura, Bufonidae del Uruguay

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    Raúl Maneyro


    Full Text Available A new species of bufonid toad of the genus Melanophryniscus from northern Uruguay is described. It is included in the M. moreirae group and its external morphology is similar to Melanophryniscus sanmartini. Melanophryniscus sp. nov. is distinguished by having a light brown dorsal coloration with six darker longitudinal glandular ridges on the dorsal surface of the body and the gular region uniformly black.Se describe una nueva especie de anuro bufónido del género Melanophryniscus, procedente del norte de Uruguay. La nueva especie se incluye en el grupo M. moreirae y es similar, en cuanto a su morfología externa, con Melanophryniscus sanmartini. Melanophryniscus sp. nov. se distingue por presentar una coloración dorsal castaño clara con seis cordones glandulares longitudinales más oscuros en la superficie dorsal del cuerpo y la región gular de color negro uniforme.

  2. Biological activities of skin and parotoid gland secretions of bufonid toads (Bufo bufo, Bufo verrucosissimus and Bufotes variabilis) from Turkey. (United States)

    Nalbantsoy, Ayse; Karış, Mert; Yalcin, Husniye Tansel; Göçmen, Bayram


    Toad glandular secretions and skin extractions contain numerous natural agents which may provide unique resources for novel drug development. Especially the skin-parotoid gland secretions of toads from genus Bufo contain as many as 86 different types of active compounds, each with the potential of becoming a potent drug. In the present study, crude skin-parotoid gland secretions from Bufo bufo, Bufo verrucosissimus and Bufotes variabilis from Turkey were screened against various cancer cells together with normal cells using MTT assay. Furthermore, the antimicrobial properties of skin secretions were tested on selected bacterial and fungal species for assessing the possible medical applications. Antimicrobial activity of skin secretions was studied by determining minimal inhibitory concentration (MIC) in broth dilution method. Hemolytic activity of each skin-secretion was also estimated for evaluating pharmaceutical potential. Both skin-parotoid gland secretions showed high cytotoxic effect on all cancerous and non-cancerous cell lines with IC50 values varying between skin-parotoid secretions of bufonid toads might be remarkable candidates for anti-cancer and antimicrobial agents without hemolytic activities.

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

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


    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.

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

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    Caroline Zank

    Full Text Available 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.

  5. Alkaloids from single skins of the Argentinian toad Melanophryniscus rubriventris (ANURA, BUFONIDAE): An unexpected variability in alkaloid profiles and a profusion of new structures. (United States)

    Garraffo, H Martin; Andriamaharavo, Nirina R; Vaira, Marcos; Quiroga, María F; Heit, Cecilia; Spande, Thomas F


    GC-MS analysis of single-skins of ten Melanophryniscus rubriventris toads (five collections of two toads each) captured during their breeding season in NW Argentina has revealed a total of 127 alkaloids of which 56 had not been previously detected in any frog or toad. Included among these new alkaloids are 23 new diastereomers of previously reported alkaloids. What is particularly distinguishing about the alkaloid profiles of these ten collections is the occurrence of many of the alkaloids, whether known or new to us, in only one of the ten skins sampled, despite two skins being obtained from each breeding site of the five populations. Many of the alkaloids are of classes known to have structures with branched-chains (e.g. pumiliotoxins and tricyclic structures) that are considered to derive from dietary mites. A large number of previously reported and new alkaloids are also of unclassified structures. Only a very few 3,5-disubstituted-indolizidine or -pyrrolizidine alkaloids are observed that have a straight-chain carbon skeleton and are likely derived from ant prey. The possible relationship of these collections made during the toad's brief breeding episodes to sequestration of dietary arthropods and individual alkaloid profiles is discussed.

  6. Niche overlap and resource partitioning among five sympatric bufonids (Anura, Bufonidae from northeastern Argentina

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    Marta I. Duré


    Full Text Available The niche overlap and resource partitioning were analyzed for five sympatric bufonids from Northeastern Argentina: Rhinella schneideri, R. bergi, R. fernandezae, R. granulosa, and Melanophryniscus cupreuscapularis. The primary objectives were to analyze the diet and pattern of coexistence relative to the microhabitats among species. The bufonids, which are primarily terrestrial, exhibited a preference for small, hard prey such as formicids or coleopterans. The smallest species preferably consumed ants, while R. schneideri preferred beetles. Significant differences were detected for the diets of these five species. In addition, significant overlap in the trophic niche was noted for all species except between R. granulosa and R. schneideri. Studying the diet behaviors and trophic parameters of sympatric species provides important data for understandingthe community and for the development of conservation guidelines.

  7. Dietary alkaloid sequestration in a poison frog: an experimental test of alkaloid uptake in Melanophryniscus stelzneri (Bufonidae). (United States)

    Hantak, Maggie M; Grant, Taran; Reinsch, Sherri; McGinnity, Dale; Loring, Marjorie; Toyooka, Naoki; Saporito, Ralph A


    Several lineages of brightly colored anurans independently evolved the ability to secrete alkaloid-containing defensive chemicals from granular glands in the skin. These species, collectively referred to as 'poison frogs,' form a polyphyletic assemblage that includes some species of Dendrobatidae, Mantellidae, Myobatrachidae, Bufonidae, and Eleutherodactylidae. The ability to sequester alkaloids from dietary arthropods has been demonstrated experimentally in most poison frog lineages but not in bufonid or eleutherodactylid poison frogs. As with other poison frogs, species of the genus Melanophryniscus (Bufonidae) consume large numbers of mites and ants, suggesting they might also sequester defensive alkaloids from dietary sources. To test this hypothesis, fruit flies dusted with alkaloid/nutritional supplement powder were fed to individual Melanophryniscus stelzneri in two experiments. In the first experiment, the alkaloids 5,8-disubstituted indolizidine 235B' and decahydroquinoline were administered to three individuals for 104 days. In the second experiment, the alkaloids 3,5-disubstituted indolizidine 239Q and decahydroquinoline were given to three frogs for 153 days. Control frogs were fed fruit flies dusted only with nutritional supplement. Gas chromatography/mass spectrometry analyses revealed that skin secretions of all experimental frogs contained alkaloids, whereas those of all control frogs lacked alkaloids. Uptake of decahydroquinoline was greater than uptake of 5,8-disubstituted indolizidine, and uptake of 3,5-disubstituted indolizidine was greater than uptake of decahydroquinoline, suggesting greater uptake efficiency of certain alkaloids. Frogs in the second experiment accumulated a greater amount of alkaloid, which corresponds to the longer duration and greater number of alkaloid-dusted fruit flies that were consumed. These findings provide the first experimental evidence that bufonid poison frogs sequester alkaloid-based defenses from dietary

  8. Alimentación en Melanophryniscus stelzneri (Anura: Bufonidae

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    Fillipelo, Ana María


    Full Text Available The alimentary categories of a population of Melanophryniscus stelzneri are studied cuantitatively and cualitatively utilizing a sample of 57 specimens obtained from "El Trapiche", province of San Luis, Argentine, in order to know the grade of trophic overlap and predation strategies. The main alimentary categories for males and females are: Formicidae, Collembola, Acari, Coleoptera, Isoptera and larvae. Although the diets of both sexes show a high grade of trophic overlap, males and females differ in the amount of each resource used. Adults and juveniles present a low grade of trophic overlap. The juveniles follow the "widely foraging" strategy and the adults follow an intermidiate one, between "sit and wait" and "widely foraging".

  9. Three New Species of Phytotelm-Breeding Melanophryniscus from the Atlantic Rainforest of Southern Brazil (Anura: Bufonidae). (United States)

    Bornschein, Marcos R; Firkowski, Carina R; Baldo, Diego; Ribeiro, Luiz F; Belmonte-Lopes, Ricardo; Corrêa, Leandro; Morato, Sérgio A A; Pie, Marcio R


    Three new species of Melanophryniscus are described from the Serra do Mar mountain range of the state of Santa Catarina, southern Brazil. All species are found at intermediate to high altitudes and share phytotelm-breeding as their reproductive strategy. The new species are distinguished from other phytotelm-breeding Melanophryniscus based on different combinations of the following traits: snout-vent length, presence of white and/or yellow spots on forearms, mouth, belly and cloaca, pattern and arrangement of warts, and presence and number of corneous spines. The discovery of these species in a rather restricted geographical area suggests that the diversity of phytotelm-breeding species of Melanophryniscus might be severely underestimated. The conservation status of these species is of particular concern, given that one of them is at risk of extinction not only due to its restricted habitat, but also because of anthropogenic disturbances.

  10. Three New Species of Phytotelm-Breeding Melanophryniscus from the Atlantic Rainforest of Southern Brazil (Anura: Bufonidae.

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    Marcos R Bornschein

    Full Text Available Three new species of Melanophryniscus are described from the Serra do Mar mountain range of the state of Santa Catarina, southern Brazil. All species are found at intermediate to high altitudes and share phytotelm-breeding as their reproductive strategy. The new species are distinguished from other phytotelm-breeding Melanophryniscus based on different combinations of the following traits: snout-vent length, presence of white and/or yellow spots on forearms, mouth, belly and cloaca, pattern and arrangement of warts, and presence and number of corneous spines. The discovery of these species in a rather restricted geographical area suggests that the diversity of phytotelm-breeding species of Melanophryniscus might be severely underestimated. The conservation status of these species is of particular concern, given that one of them is at risk of extinction not only due to its restricted habitat, but also because of anthropogenic disturbances.

  11. Three New Species of Phytotelm-Breeding Melanophryniscus from the Atlantic Rainforest of Southern Brazil (Anura: Bufonidae) (United States)

    Bornschein, Marcos R.; Firkowski, Carina R.; Baldo, Diego; Ribeiro, Luiz F.; Belmonte-Lopes, Ricardo; Corrêa, Leandro; Morato, Sérgio A. A.; Pie, Marcio R.


    Three new species of Melanophryniscus are described from the Serra do Mar mountain range of the state of Santa Catarina, southern Brazil. All species are found at intermediate to high altitudes and share phytotelm-breeding as their reproductive strategy. The new species are distinguished from other phytotelm-breeding Melanophryniscus based on different combinations of the following traits: snout-vent length, presence of white and/or yellow spots on forearms, mouth, belly and cloaca, pattern and arrangement of warts, and presence and number of corneous spines. The discovery of these species in a rather restricted geographical area suggests that the diversity of phytotelm-breeding species of Melanophryniscus might be severely underestimated. The conservation status of these species is of particular concern, given that one of them is at risk of extinction not only due to its restricted habitat, but also because of anthropogenic disturbances. PMID:26630281

  12. A new species of Melanophryniscus (Anura, Bufonidae from the Campos Gerais region of Southern Brazil

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    Giovanna C. Steinbach-Padilha


    Full Text Available A new species of Melanophryniscus is described from the Parque Estadual de Vila Velha, municipality of Ponta Grossa, Paraná State,Southern Brazil. The Parque Estadual de Vila Velha is located in the Campos Gerais region, an environment dominated by natural grasslands with patches of Araucaria Forest. The new species is distinguished from all congeners by its small size (12.8-14.0 mm snout-vent length in adult males and unique color pattern of copper brown dorsum covered with small spinulose black warts; ventral surface black finely spotted with white, posterior abdomen and ventral surfaces of the forearm, hand and foot with red stains. The new species is nocturnal and breeds in the water accumulated in the leaf-axils of phytotelmata.

  13. Chloride channels in toad skin

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    Larsen, Erik Hviid; Rasmussen, B E


    A study of the voltage and time dependence of a transepithelial Cl- current in toad skin (Bufo bufo) by the voltage-clamp method leads to the conclusion that potential has a dual role for Cl- transport. One is to control the permeability of an apical membrane Cl-pathway, the other is to drive Cl...

  14. Use of Reproductive Microhabitat by Melanophryniscus montevidensis (Anura: Bufonidae) from Uruguay. (United States)

    Pereira, Gisela; Maneyro, Raúl


    This study describes the reproductive microhabitat of Melanophryniscus montevidensis and its use in two water bodies (WBs) in Barra de la Laguna de Rocha, Uruguay. Monthly field trips were performed between March 2012 and February 2013. Variables related to the WBs and vegetation, as well as parameters linked to the usage the amphibians make of the site (e.g: distance to the border of the pond, water depth and the vegetation use) were recorded. The behavior shown by the individuals during the breeding activity was recorded. This activity occurs in shallow temporary WBs with abundant hydrophilic vegetation. The individuals were found more frequently in areas near the edge of the pond, which has denser vegetation. The calling males were found closer to the border of the pond, and they showed better body condition than the non-calling males. In addition to calling activities, males used alternative tactics to find couples, such as active search of females, and aggressive behaviors, such as male displacing and physical combat. Such behaviors are common in anurans with explosive reproductive dynamics. The characterization of the reproductive microhabitats permits the proposal of strategies for the conservation of the species in Uruguay, given that the loss and fragmentation of habitats is one of the main causes considered for the decrease in their populations.

  15. Validity of photo-identification technique to analyze natural markings in Melanophryniscus montevidensis (Anura: Bufonidae

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    Ernesto Elgue


    Full Text Available Individual identification is useful for answering a variety of biological questions about animal life histories. Most of the techniques used to mark amphibians are invasive and can cause negative effects, compromising individual survivorship and biasing studies. Photo-identification consists in the identification of specimens based on photographic records of unique color-design patterns. This technique has been used with success in several amphibian species. Melanophryniscus montevidensis is an endangered anuran species inhabiting the Uruguayan Atlantic coast. The general pattern of coloration is black with red and yellow blotches on the belly. In this study, we validated the technique of photo-identification assisted by software for individual recognition in M. montevidensis using natural markings. Field trips were performed over 16 months during which, the ventral color pattern of specimens was photographed. The photos were edited and analyzed with the Wild-ID 1.0 software for photographic reconnaissance. An efficiency of 100% was obtained in the visual recognition and 90% in the detection of recaptures using the software. The use of photo-identification using natural marks is an effective technique in this species, because the color pattern of the belly was highly variable among individuals and remained unchanged in individuals over the 16 month period. In this evaluation the use of software for photo-identification was necessary for the treatment of large databases.

  16. Reproducción y desarrollo larval del sapo enano Melanophryniscus stelzneri stelzneri (Weyemberg, 1875 (Anura: Bufonidae

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    Bustos Singer, Rodrigo


    Full Text Available Se estudiaron varios aspectos de la reproducción y desarrollo larval de Melanophryniscus stelzneri stelzneri: condiciones ambientales en las que ocurre la reproducción, conductas pre y postreproductivas de los adultos, puesta, desarrollo embrionario, comportamiento larval, y metamorfosis. Se realizó también una descripción anatómica de la larva. La mayor parte de las conductas observadas son corrientes en anuros argentinos. La larva es típicamente pequeña y de tipo léntico-bentónica. Su fórmula dentaria mas común es 2 / 3. El tiempo de metamorfosis está afectada por la disponibilidad de agua, un paulatino descenso en el nivel de agua la acelera. Many aspects about the reproduction of Melanophryniscus stelzneri stelzneri were estudied: environmental conditions in which reproduction occurs, pre and postreproductive adult behaviour, oviposition, larval developement, tadpole habits and metamorphosis. An anatomic description of the larva was also realized. Most of the observed behaviours are usual in argentinian anurans. The tadpole is tiny and typically lentic- bentonic. The most conmon queratodontic formula is 2 / 3. The time of metamorphosis is affected by water availability. A decreasing level of water accelerates the development.

  17. Diseases of frogs and toads (United States)

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


    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

  18. Sulfate transport in toad skin

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    Larsen, Erik Hviid; Simonsen, K


    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...

  19. Reported Experiences Enhance Favourable Attitudes toward Toads (United States)

    Tomazic, Iztok


    There are many factors that influence the formation of attitudes, one of the most crucial ones being education. Positive attitudes toward animals can be effectively accomplished principally by enabling students to directly experience organisms and their environments. The following study presents the development of a Toad Attitude Questionnaire…

  20. Toad poisoning in three dogs: case reports

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    CM Barbosa


    Full Text Available Toad poisoning is frequent in dogs, but has been infrequently addressed in published case reports and review articles. Dogs can be poisoned when they bite a toad or otherwise ingest the venom. The venom effects manifest soon after the accident, since the toxin is rapidly absorbed by the mucous membrane of the digestive system. Hospital records of three dogs, diagnosed with toad poisoning, were retrospectively reviewed from January 2005 to July 2007. Poisoned dogs may present only local irritation or systemic signs in the gastrointestinal, cardiac and neurological systems. All three cases presented herein had clinical signs of gastrointestinal alterations including vomiting, sialorrhea and diarrhea. Two dogs developed abnormal cardiac rhythm and two exhibited neurological signs. A poisoned animal requires emergency care and symptomatic therapy with intense monitoring of its clinical parameters. Although there have been reports on the low mortality of dogs poisoned by toads, one animal died even after appropriate therapy. The severity of clinical signs and the risk of death must be considered by the veterinarian.

  1. Estimation of temporary emigration in male toads (United States)

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


    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.

  2. Kinematics of Chinese toad Bufo gargarizans

    Institute of Scientific and Technical Information of China (English)


    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.

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

  4. Determinants of Instrumental Extinction in Terrestrial Toads ("Bufo arenarum") (United States)

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


    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…

  5. Genetic differentiation between African and European Midwife Toads (Alytes, Discoglossidae)

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    Arntzen, J.W.; Szymura, J.M.


    Toads of the genus Alytes from the Rif mountains in Morocco are electrophoretically very similar to Iberian Alytes obstetricans (DieN = 0.07). Genetic distance estimates across the Straits of Gibraltar do not exceed the values found among European samples. The data point to relatively recent coloniz

  6. Behavior of toads, Bufo bufo, in a dynamic environment. (United States)

    Lychakov, D V


    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.

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

    el-Mofty, M M; Sakr, S A


    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.

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


    Isioma Tongo; Lawrence Ezemonye; Uche Ochei


    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 oxida...

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

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


    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.

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

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    Isioma Tongo


    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.

  11. Fatal attraction: adaptations to prey on native frogs imperil snakes after invasion of toxic toads. (United States)

    Hagman, Mattias; Phillips, Benjamin L; Shine, Richard


    Adaptations that enhance fitness in one situation can become liabilities if circumstances change. In tropical Australia, native snake species are vulnerable to the invasion of toxic cane toads. Death adders (Acanthophis praelongus) are ambush foragers that (i) attract vertebrate prey by caudal luring and (ii) handle anuran prey by killing the frog then waiting until the frog's chemical defences degrade before ingesting it. These tactics render death adders vulnerable to toxic cane toads (Bufo marinus), because toads elicit caudal luring more effectively than do native frogs, and are more readily attracted to the lure. Moreover, the strategy of delaying ingestion of a toad after the strike does not prevent fatal poisoning, because toad toxins (unlike those of native frogs) do not degrade shortly after the prey dies. In our laboratory and field trials, half of the death adders died after ingesting a toad, showing that the specialized predatory behaviours death adders use to capture and process prey render them vulnerable to this novel prey type. The toads' strong response to caudal luring also renders them less fit than native anurans (which largely ignored the lure): all toads bitten by adders died. Together, these results illustrate the dissonance in behavioural adaptations that can arise following the arrival of invasive species, and reveal the strong selection that occurs when mutually naive species first interact.

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

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    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.

  13. All-optical pseudorandom bit sequences generator based on TOADs (United States)

    Sun, Zhenchao; Wang, Zhi; Wu, Chongqing; Wang, Fu; Li, Qiang


    A scheme for all-optical pseudorandom bit sequences (PRBS) generator is demonstrated with optical logic gate 'XNOR' and all-optical wavelength converter based on cascaded Tera-Hertz Optical Asymmetric Demultiplexer (TOADs). Its feasibility is verified by generation of return-to-zero on-off keying (RZ-OOK) 263-1 PRBS at the speed of 1 Gb/s with 10% duty radio. The high randomness of ultra-long cycle PRBS is validated by successfully passing the standard benchmark test.

  14. Winter hibernation and UCHL1-p34cdc2 association in toad oocyte maturation competence.

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    Zhichao Kuang

    Full Text Available Currently, it is believed that toad oocyte maturation is dependent on the physiological conditions of winter hibernation. Previous antibody-blocking experiments have demonstrated that toad ubiquitin carboxyl-terminal hydrolase L1 (tUCHL1 is necessary for germinal vesicle breakdown during toad oocyte maturation. In this paper, we first supply evidence that tUCHL1 is highly evolutionarily conserved. Then, we exclude protein availability and ubiquitin carboxyl-terminal hydrolase enzyme activity as factors in the response of oocytes to winter hibernation. In the context of MPF (maturation promoting factor controlling oocyte maturation and to further understand the role of UCHL1 in oocyte maturation, we performed adsorption and co-immunoprecipitation experiments using toad oocyte protein extracts and determined that tUCHL1 is associated with MPF in toad oocytes. Recombinant tUCHL1 absorbed p34(cdc2, a component of MPF, in obviously larger quantities from mature oocytes than from immature oocytes, and p13(suc1 was isolated from tUCHL1 with a dependence on the ATP regeneration system, suggesting that still other functions may be involved in their association that require phosphorylation. In oocytes from hibernation-interrupted toads, the p34(cdc2 protein level was significantly lower than in oocytes from toads in artificial hibernation, providing an explanation for the different quantities isolated by recombinant tUCHL1 pull-down and, more importantly, identifying a mechanism involved in the toad oocyte's dependence on a low environmental temperature during winter hibernation. Therefore, in toads, tUCHL1 binds p34(cdc2 and plays a role in oocyte maturation. However, neither tUCHL1 nor cyclin B1 respond to low temperatures to facilitate oocyte maturation competence during winter hibernation.

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

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    Annemarie Ohler


    Full Text Available 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.

  16. Sensory feedback and coordinating asymmetrical landing in toads. (United States)

    Cox, S M; Gillis, Gary B


    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.

  17. 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


    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....

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

  19. Temperature, hydric environment, and prior pathogen exposure alter the experimental severity of chytridiomycosis in boreal toads (United States)

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


    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.

  20. Batrachochytrium dendrobatidis detected in Kihansi spray toads at a captive breeding facility (Kihansi, Tanzania). (United States)

    Makange, Mariam; Kulaya, Neema; Biseko, Emiliana; Kalenga, Parson; Mutagwaba, Severinus; Misinzo, Gerald


    The chytrid fungus Batrachochytrium dendrobatidis (Bd) is the aetiological agent of amphibian chytridiomycosis, a disease associated with global amphibian population declines. In November 2012, mass mortalities of Kihansi spray toads Nectophrynoides asperginis were observed at the Kihansi captive breeding facility, located in the Udzungwa Mountains, Tanzania. Mortalities increased rapidly, and dead toads showed typical clinical signs of chytridiomycosis, including reddening of the skin that was especially evident on the toe pads. Treatment of toads with itraconazole rapidly reduced mortalities. Dead toads (n = 49) were collected and used to perform Bd-specific polymerase chain reaction and subsequent nucleotide sequencing. All toads collected at the facility were positive for Bd. The obtained Bd 5.8S rRNA gene and flanking internal transcribed spacer regions (ITS1 and ITS2) were not 100% identical to any other Bd sequences in GenBank, but closely resembled isolates from Ecuador, Japan, USA, Brazil, Korea, and South Africa. To our knowledge, this is the first study reporting molecular characteristics of Bd isolated from the Udzungwa Mountains. Strict biosecurity measures at the breeding facility and in Kihansi spray wetlands where toads have been reintroduced have been implemented. Further studies on Bd epidemiology in the Udzungwa Mountains are recommended in order to understand its origin, prevalence, and molecular characteristics in wild amphibian populations. This will be important for conservation of several endemic amphibian species in the Udzungwa Mountains, which are part of the Eastern Arc Mountains, a global biodiversity hotspot.

  1. Origin and genome evolution of polyploid green toads in Central Asia: evidence from microsatellite markers. (United States)

    Betto-Colliard, C; Sermier, R; Litvinchuk, S; Perrin, N; Stöck, M


    Polyploidization, which is expected to trigger major genomic reorganizations, occurs much less commonly in animals than in plants, possibly because of constraints imposed by sex-determination systems. We investigated the origins and consequences of allopolyploidization in Palearctic green toads (Bufo viridis subgroup) from Central Asia, with three ploidy levels and different modes of genome transmission (sexual versus clonal), to (i) establish a topology for the reticulate phylogeny in a species-rich radiation involving several closely related lineages and (ii) explore processes of genomic reorganization that may follow polyploidization. Sibship analyses based on 30 cross-amplifying microsatellite markers substantiated the maternal origins and revealed the paternal origins and relationships of subgenomes in allopolyploids. Analyses of the synteny of linkage groups identified three markers affected by translocation events, which occurred only within the paternally inherited subgenomes of allopolyploid toads and exclusively affected the linkage group that determines sex in several diploid species of the green toad radiation. Recombination rates did not differ between diploid and polyploid toad species, and were overall much reduced in males, independent of linkage group and ploidy levels. Clonally transmitted subgenomes in allotriploid toads provided support for strong genetic drift, presumably resulting from recombination arrest. The Palearctic green toad radiation seems to offer unique opportunities to investigate the consequences of polyploidization and clonal transmission on the dynamics of genomes in vertebrates.

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

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    K.P. Dinesh


    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.

  3. The All Optical New Universal Gate Using TOAD

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    Goutam Kumar Maity


    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.

  4. Detection of single photons by toad and mouse rods. (United States)

    Reingruber, Jürgen; Pahlberg, Johan; Woodruff, Michael L; Sampath, Alapakkam P; Fain, Gordon L; Holcman, David


    Amphibian and mammalian rods can both detect single photons of light even though they differ greatly in physical dimensions, mammalian rods being much smaller in diameter than amphibian rods. To understand the changes in physiology and biochemistry required by such large differences in outer segment geometry, we developed a computational approach, taking into account the spatial organization of the outer segment divided into compartments, together with molecular dynamics simulations of the signaling cascade. We generated simulations of the single-photon response together with intrinsic background fluctuations in toad and mouse rods. Combining this computational approach with electrophysiological data from mouse rods, we determined key biochemical parameters. On average around one phosphodiesterase (PDE) molecule is spontaneously active per mouse compartment, similar to the value for toad, which is unexpected due to the much smaller diameter in mouse. A larger number of spontaneously active PDEs decreases dark noise, thereby improving detection of single photons; it also increases cGMP turnover, which accelerates the decay of the light response. These constraints explain the higher PDE density in mammalian compared with amphibian rods that compensates for the much smaller diameter of mammalian disks. We further find that the rate of cGMP hydrolysis by light-activated PDE is diffusion limited, which is not the case for spontaneously activated PDE. As a consequence, in the small outer segment of a mouse rod only a few activated PDEs are sufficient to generate a signal that overcomes noise, which permits a shorter lifetime of activated rhodopsin and greater temporal resolution.

  5. Influence of demography and environment on persistence in toad populations (United States)

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


    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

  6. 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 (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...

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


    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.

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

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


    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.

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

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    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.

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


    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.

  11. 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)


    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.

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

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


    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.

  13. Multiple paternity in a viviparous toad with internal fertilisation (United States)

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


    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.

  14. Indirect evidence for elastic energy playing a role in limb recovery during toad hopping


    Schnyer, Ariela; Gallardo, Mirialys; Cox, Suzanne; Gillis, Gary


    Elastic energy is critical for amplifying muscle power during the propulsive phase of anuran jumping. In this study, we use toads (Bufo marinus) to address whether elastic recoil is also involved after take-off to help flex the limbs before landing. The potential for such spring-like behaviour stems from the unusually flexed configuration of a toad's hindlimbs in a relaxed state. Manual extension of the knee beyond approximately 90° leads to the rapid development of passive tension in the lim...

  15. [Lectin histochemistry of the Bufo marinus L. toad tongue]. (United States)

    González Elorriaga, M; Jaloveckas, D; Salazar de Candelle, M


    Lectin histochemistry at light microscope level was used in the tongue of the cane toad Bufo marinus to determine the distribution of sugar residues in glycoconjugates (GCs) previously localized and characterized by conventional histochemical techniques. Five horseradish-peroxidase (HRP) labeled-lectins, namely Con A, PNA, SBA, UEA-1 and WGS were used. Additionally, neuraminidase (N) treated sections before the staining procedures were used in order to dilucidate the presence of terminal sialic acid (SA). Sugar residues in GCs of the taste organ (TO) associated mucous cells stained more intensely with WGA than with Con A and UEA-1. All the sensory cells reacted with Con A and WGA but one type of them were characteristically labeled by UEA-1. The glycocalix (gc) of the TOs resulted intensely stained with Con A and with WGA and UEA-1 before and after N treatment. The GCs in the mucous-supporting cells of dorsal mucosae filiform papillae and folds reacted intensely with WGA and weakly with Con A. The ciliated cells (cic) were intense and characteristically stained with UEA-1 and WGA and moderately with Con A. The gc reacted more intensely with WGA than with Con A. Dorsal mucosae glands secretory cells mucins were characteristically stained with PNA, SBA and WGA besides Con A, while glandular ciliated cells showed the same staining pattern as in the filiform papillae. In the ventral mucosa all epithelium cells resulted stained with WGA and Con A, while differentiated goblet cells only reacted as well with UEA-1 and PNA before and after neuraminidase treatment. Unexpectedly, ciliated ventral mucosae cells did not react with UEA-1 but only with WGA and Con A. The results have shown that lectin histochemistry is an interesting tool to characterize similarities and differences in the lingual GCs sugar residues composition and distribution, particularly those located in epithelial cells.

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

    Hanner, R H; Ryan, G B


    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.

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

    Directory of Open Access Journals (Sweden)

    Ji Qi


    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.

  18. Etomidate anaesthesia by immersion in oriental fire-bellied toads (Bombina orientalis). (United States)

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


    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.

  19. 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.

  20. Baroreceptor control of heart rate in the awake toad: peripheral autonomic effectors and arterial baroreceptor areas. (United States)

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


    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.


    Institute of Scientific and Technical Information of China (English)

    WANGYu-Feng; CHENGJiun; CHENGZhi-Ping


    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. [The comparative aspects of spatial ecology of lizards exemplified by the toad-headed lizards (Reptilia, Agamidae, Phrynocephalus)]. (United States)

    Semenov, D V


    The possibility of analysis of phylogenetic parameters of the spatial distribution of populations is discussed by an example of the agamid toad-headed lizards (Phrynocephalus). Summarizing both original and published data on the individual home ranges and the relocation of individuals of 30 populations from 12 species showed that differentiation of the type of spatial distribution is weak in toad-headed lizards. This observation confirms the idea that this clade of agamids is phylogenetically young and relatively recently radiated. At the interspecific level, positive correlation between home range size and body size was observed in the studied group. Such spatial parameters, shared by all toad-headed lizards, as relatively large size and weakly structured individual home ranges can be explained by the peculiarities of their reproduction features and their foraging mode. The individual type of space-usage in toad-headed does not fit the traditional scheme dividing all the lizards into the territorial Iguania and the nonterritorial Autarchoglossa.

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

  4. Correction of locality records for the endangered arroyo toad (Anaxyrus californicus) from the desert region of southern California (United States)

    Ervin, Edward L.; Beaman, Kent R.; Fisher, Robert N.


    The recovery strategy for an endangered species requires accurate knowledge of its distribution and geographic range. Although the best available information is used when developing a recovery plan, uncertainty often remains in regard to a species actual geographic extent. The arroyo toad (Anaxyrus californicus) occurs almost exclusively in coastal drainages, from Monterey County, California, south into northwestern Baja California, Mexico. Through field reconnaissance and the study of preserved museum specimens we determined that the four reported populations of the arroyo toad from the Sonoran Desert region of Riverside, San Diego, and Imperial counties, California are in error. Two additional sites in the Sonoran Desert are discussed regarding the possibility that the arroyo toad occurs there. We recommend the continued scrutiny of arroyo toad records to maintain a high level of accuracy of its distribution and geographic extent.

  5. Prevalence of Salmonella spp. in cane toads (Bufo marinus) from Grenada, West Indies, and their antimicrobial susceptibility. (United States)

    Drake, M; Amadi, V; Zieger, U; Johnson, R; Hariharan, H


    Cloacal swabs and caecal contents sampled from 58 cane toads (Bufo marinus) in St George's parish, Grenada, during a 7-month period in 2011 were examined by an enrichment and selective culture method for presence of Salmonella spp. Twenty-four (41%) toads were positive for Salmonella spp. of which eight were Salmonella enterica serovar Javiana, and eight were S. enterica serovar Rubislaw. The other serovars were as follows: Montevideo, 6; Arechavaleta, 1; and serovar: IV:43:-:-, 1. The high frequency of isolation of serovar Javiana, an emerging human pathogen associated with several outbreaks in the recent years in the eastern United States, suggests a possible role for cane toads in transmission of this serovar. Although S. Rubislaw has been isolated from lizards, bats and cases of some human infections, there is no report of its carriage by cane toads, and in such high frequency. The rate of carriage of S. Montevideo, a cause for human foodborne outbreaks around the world was also over 10% in the 58 toads sampled in this study. The antimicrobial drug susceptibility tests against amoxicillin-clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, imipenem, nalidixic acid, streptomycin, tetracycline and trimethoprim-sulfamethoxazole showed that drug resistance is minimal and is of little concern. Antimicrobial resistance was limited to ampicillin and amoxicillin-clavulanic acid in one isolate of S. Javiana and one isolate of S. Rubislaw. This is the first report of isolation and antimicrobial susceptibilities of various Salmonella serovars not identified previously in cane toads in Grenada, West Indies.

  6. Corticosteroid responses of snakes to toxins from toads (bufadienolides) and plants (cardenolides) reflect differences in dietary specializations. (United States)

    Mohammadi, Shabnam; French, Susannah S; Neuman-Lee, Lorin A; Durham, Susan L; Kojima, Yosuke; Mori, Akira; Brodie, Edmund D; Savitzky, Alan H


    Toads are chemically defended by cardiotonic steroids known as bufadienolides. Resistance to the acute effects of bufadienolides in snakes that prey on toads is conferred by target-site insensitivity of the toxin's target enzyme, the Na(+)/K(+)-ATPase. Previous studies have focused largely on the molecular mechanisms of resistance but have not investigated the physiological mechanisms or consequences of exposure to the toxins. Adrenal enlargement in snakes often is associated with specialization on a diet of toads. These endocrine glands are partly composed of interrenal tissue, which produces the corticosteroids corticosterone and aldosterone. Corticosterone is the main hormone released in response to stress in reptiles, and aldosterone plays an important role in maintaining ion balance through upregulation of Na(+)/K(+)-ATPase. We tested the endocrine response of select species of snakes to acute cardiotonic steroid exposure by measuring circulating aldosterone and corticosterone concentrations. We found that Rhabdophis tigrinus, which specializes on a diet of toads, responds with lower corticosterone and higher aldosterone compared to other species that exhibit target-site resistance to the toxins but do not specialize on toads. We also found differences between sexes in R. tigrinus, with males generally responding with higher corticosterone and aldosterone than females. This study provides evidence of physiological adaptations, beyond target-site resistance, associated with tolerance of bufadienolides in a specialized toad-eating snake.

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

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


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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

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

    DEFF Research Database (Denmark)

    Katz, U; Larsen, Erik Hviid


    The steady-state Cl- current across the skin of Bufo viridis adapted to tap water was found to be rectified. In skins bathed with NaCl Ringer on both sides, a large outward current, carried by influx of Cl-, was observed at a clamping voltage (V) of less than -50 mV (outside of the skin negative......, and apparent leakage conductance was reduced. Application of the phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine to skin of fully salt-adapted toads increased the transepithelial Cl- conductance, and the time courses of voltage clamp currents became more like those of water-adapted toads. Apparent...... leakage conductance was increased.(ABSTRACT TRUNCATED AT 400 WORDS)...

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

    CERN Document Server

    House, Donald


    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. ...

  11. Variation in body size and metamorphic traits of Iberian spadefoot toads over a short geographic distance



    Determinants of geographic variation in body size are often poorly understood, especially in organisms with complex life cycles. We examined patterns of adult body size and metamorphic traits variation in Iberian spadefoot toad (Pelobates cultripes) populations, which exhibit an extreme reduction in adult body size, 71.6% reduction in body mass, within just about 30 km at south-western Spain. We hypothesized that size at and time to metamorphosis would be predictive of the spatial pattern obs...

  12. Large male mating advantage in natterjack toads, Bufo calamita: Sexual selection or energetic constraints?



    Variation in the effect of male body size on mating success was studied in natterjack toads during two breeding seasons with different temporal patterns of reproductive activity. Larger males were more likely to mate than small males in the season with a single peak and continuous breeding activity, whereas random mating by size was found when reproduction occurred during several peaks separated by periods of inactivity. Playback tests did not reveal any consistent preference by females for c...

  13. Community of helminth parasites of thorny toad Rhinella Spinulosa (Anura: Bufonidae) of Peru


    Chero, Jhon; Laboratorio de Parasitología, Facultad de Ciencias Naturales y Matemática (FCNNM), Universidad Nacional Federico Villarreal (UNFV), Lima; Cruces, Celso; Laboratorio de Parasitología, Facultad de Ciencias Naturales y Matemática (FCNNM), Universidad Nacional Federico Villarreal (UNFV), Lima; Iannacone, José; Laboratorio de Ecología y Biodiversidad Animal (LEBA), Facultad de Ciencias Naturales y Matemática (FCNNM). Universidad Nacional Federico Villarreal (UNFV), Lima; Sáez, Gloria; Laboratorio de Parasitología, Facultad de Ciencias Naturales y Matemática (FCNNM), Universidad Nacional Federico Villarreal (UNFV), Lima; Alvariño, Lorena; Laboratorio de Ecología y Biodiversidad Animal (LEBA), Facultad de Ciencias Naturales y Matemática (FCNNM). Universidad Nacional Federico Villarreal (UNFV), Lima; Luque, José; Departamento de Parasitologia Animal, Curso de Pós-graduação em Ciências Veterinárias, Universidade Federal Rural do Rio de Janeiro – UFRRJ, Seropédica, Rio de Janeiro; Morales, Víctor; Facultad de Ciencias Biológicas, Universidad Ricardo Palma (URP), Lima


    The aim of this study was to evaluate the community of metazoan parasites of thorny toad Rhinella spinulosa of Peru and elucidate whether sex and the total length of the hosts amphibians are structuring their communities of parasites. Ninety specimens of R. spinulosa were acquired during May 2009 to October 2010. The body cavity, gastrointestinal tract, bladder, lungs and muscles were examined to search for metazoan parasites. Seven taxa of metazoan parasites were collected: one digenean [Gor...

  14. Vasculature of the parotoid glands of four species of toads (bufonidae: bufo). (United States)

    Hutchinson, Deborah A; Savitzky, Alan H


    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.

  15. Modelling the extinction risk of isolated populations of natterjack toad Bufo calamita

    Directory of Open Access Journals (Sweden)

    F. Meyer


    Full Text Available Many local populations of the natterjack toad Bufo calamita in Germany are endangered. Due to the fragmentation and destruction of natural habitats by man, toads have often been forced to switch to secondary habitats. The permanent existence of these habitats is uncertain. Habitat and area requirements have been investigated in various parts of Germany in recent years. Our study uses field observations from sites in Halle (Saxony-Anhalt and List (Schleswig-Holstein as a basis for analyses of the population dynamics under different environmental conditions. Deterministic trends of these populations are calculated with the help of a Leslie matrix consisting of average parameters for mortality and reproduction. For a more thorough analysis we use a stochastic simulation model in order to assess survival probabilities of local toad populations. This model also takes into account environmental fluctuations affecting mortality and reproduction. Using scenarios from different locations, a sensitivity analysis of the parameters indicates which management options are the most promising to preserve a population. Our results indicate that the mortality rates of juveniles and the availability of spawning ground have the greatest influence on a population’s survival. Consequently, habitat management should focus on these aspects. In addition, we investigate the risk of extinction for different reproductive strategies. Natterjack toad populations observed in the field actually follow a strategy with three breeding periods. We find that this strategy supports the survival of the population better than strategies with less periods, which are more likely to result in a complete breeding failure during one season.

  16. Soil organic matter content effects on dermal pesticide bioconcentration in American toads (Bufo americanus). (United States)

    Van Meter, Robin J; Glinski, Donna A; Henderson, W Matthew; Purucker, S Thomas


    Pesticides have been implicated as a major factor in global amphibian declines and may pose great risk to terrestrial phase amphibians moving to and from breeding ponds on agricultural landscapes. Dermal uptake from soil is known to occur in amphibians, but predicting pesticide availability and bioconcentration across soil types is not well understood. The present study was designed to compare uptake of 5 current-use pesticides (imidacloprid, atrazine, triadimefon, fipronil, and pendimethalin) in American toads (Bufo americanus) from exposure on soils with significant organic matter content differences (14.1% = high organic matter and 3.1% = low organic matter). We placed toads on high- or low-organic matter soil after applying individual current-use pesticides on the soil surface for an 8-h exposure duration. Whole body tissue homogenates and soils were extracted and analyzed using liquid chromatography-mass spectrometry to determine pesticide tissue and soil concentration, as well as bioconcentration factor in toads. Tissue concentrations were greater on the low-organic matter soil than the high-organic matter soil across all pesticides (average ± standard error; 1.23 ± 0.35 ppm and 0.78 ± 0.23 ppm, respectively), and bioconcentration was significantly higher for toads on the low-organic matter soil (analysis of covariance p = 0.002). Soil organic matter is known to play a significant role in the mobility of pesticides and bioavailability to living organisms. Agricultural soils typically have relatively lower organic matter content and serve as a functional habitat for amphibians. The potential for pesticide accumulation in amphibians moving throughout agricultural landscapes may be greater and should be considered in conservation and policy efforts. Environ Toxicol Chem 2016;35:2734-2741. © 2016 SETAC.

  17. All-Optical Terahertz Optical Asymmetric Demultiplexer (toad) Based Binary Comparator:. a Proposal (United States)

    Chattopadhyay, Tanay

    Comparator determines whether a number is greater than, equals to or less than another number. It plays a significant role in fast central processing unit in all-optical scheme. In all-optical scheme here 1-bit binary comparator is proposed and described by Terahertz Optical Asymmetric Demultiplexer (TOAD) based interferometric switch. Simulation result by Mathcad-7 is also given. Cascading technique of building up the n-bit binary comparator with this 1-bit comparator block is also proposed here.

  18. Storage and recovery of elastic potential energy powers ballistic prey capture in toads. (United States)

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


    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.

  19. Effects of weather on survival in populations of boreal toads in Colorado (United States)

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


    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.

  20. Effects of Multiple Routes of Cadmium Exposure on the Hibernation Success of the American Toad (Bufo americanus) (United States)

    James, S.M.; Little, E.E.; Semlitsch, R.D.


    The effects of multiple routes of cadmium exposure on juvenile American toads (Bufo americanus) were evaluated using environmentally relevant concentrations. During or after exposure, toads were individually hibernated for 172 days at approximately 4??C. The following experiments were conducted: (1) dermal exposure (hibernation in soil contaminated with up to 120 ??g Cd/ g (dry weight)); (2) injection exposure (single injection with cadmium to achieve a maximum whole-body nominal concentration of 3 ??g Cd/g (wet weight) 12 days before hibernation in uncontaminated soil); and, (3) oral exposure (feeding with mealworms containing ???16 ??g Cd/g (dry weight) for 50 days before hibernation in uncontaminated soil)., We hypothesized that sublethal levels of cadmium would become lethal during hibernation because of combined chemical and cold stress. No prehibernation mortality occurred in the injection and oral exposure studies. There was a significant treatment effect on whole-body cadmium concentration in toads orally or dermally exposed and on percent of cadmium retention in toads orally exposed. There was also a trend of increased time-to-burrowing and more toads partially buried with greater cadmium concentration in the dermal study, which indicated avoidance. In all 3 experiments, no significant differences were found among cadmium treatments in hibernation survival, percent of mass loss, or locomotor performance. However, toads fed mealworms averaging 4.7 ??g Cd/g (dry weight) had only 56% survival compared with 100% survival for controls. Although our results suggest that environmentally relevant levels of cadmium do not pose a great risk to American toads, factors such as soil type or prey species may increase cadmium bioavailability, and other amphibian species may be more sensitive to cadmium than B. americanus.

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

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


    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.

  2. Reduce torques and stick the landing: limb posture during landing in toads. (United States)

    Azizi, Emanuel; Larson, Neil P; Abbott, Emily M; Danos, Nicole


    A controlled landing, where an animal does not crash or topple, requires enough stability to allow muscles to effectively dissipate mechanical energy. Toads (Rhinella marina) are exemplary models for understanding the mechanics and motor control of landing given their ability to land consistently during bouts of continuous hopping. Previous studies in anurans have shown that ground reaction forces (GRFs) during landing are significantly higher compared with takeoff and can potentially impart large torques about the center of mass (COM), destabilizing the body at impact. We predict that in order to minimize such torques, toads will align their COM with the GRF vector during the aerial phase in anticipation of impact. We combined high-speed videography and force-plate ergometry to quantify torques at the COM and relate the magnitude of torques to limb posture at impact. We show that modulation of hindlimb posture can shift the position of the COM by about 20% of snout-vent length. Rapid hindlimb flexion during the aerial phase of a hop moved the COM anteriorly and reduced torque by aligning the COM with the GRF vector. We found that the addition of extrinsic loads did not significantly alter landing behavior but did change the torques experienced at impact. We conclude that anticipatory hindlimb flexion during the aerial phase of a hop is a critical feature of a mechanically stable landing that allows toads to quickly string together multiple, continuous hops.

  3. An electrophoretic study of myosin heavy chain expression in skeletal muscles of the toad Bufo marinus. (United States)

    Nguyen, L T; Stephenson, G M


    In this study we developed an SDS-PAGE protocol which for the first time separates effectively all myosin heavy chain (MHC) isoforms expected to be expressed in iliofibularis (IF), pyriformis (PYR), cruralis (CRU) and sartorius (SAR) muscles of the toad Bufo marinus on the basis of previously reported fibre type composition. The main feature of the method is the use of alanine instead of glycine both in the separating gel and in the running buffer. The correlation between the MHC isoform composition of IF, SAR and PYR muscles determined in this study and the previously reported fibre type composition of IF and SAR muscles in the toad and of PYR muscle in the frog was used to tentatively identify the MHC isoforms expressed by twitch fibre types 1, 2 and 3 and by tonic fibres. The alanine-SDS electrophoretic method was employed to examine changes in the MHC composition of IF, PYR, CRU and SAR muscles with the ontogenetic growth of the toad from post-natal life (body weight muscle observed in this study are in very good agreement with those in the fibre type composition of the developing IF muscle reported in the literature.

  4. Ventilatory behaviors of the toad Bufo marinus revealed by coherence analysis

    Directory of Open Access Journals (Sweden)

    F. C. Coelho

    Full Text Available Breathing in amphibians is a remarkably complex behavior consisting of irregular breaths that may be taken singly or in bouts that are used to deflate and inflate the lungs. The valves at the two outlets of the buccal cavity (nares and glottis need to be finely controlled throughout the bout for the expression of these complex respiratory behaviors. In this study, we use a technique based on the calculation of the coherence spectra between respiratory variables (buccal pressure; narial airflow; and lung pressure. Coherence was also used to quantify the effects of chemoreceptor and pulmonary mechanoreceptor input on narial and glottal valve behavior on normoxic, hypoxic, and hypercapnic toads with both intact and bilaterally sectioned pulmonary vagi. We found a significant reduction in narial coherence in hypoxic vagotomized toads indicating that pulmonary mechanoreceptor feedback modulates narial opening duration. An unexpectedly high coherence between Pl and Pb during non-respiratory buccal oscillations in hypercapnic toads indicated more forceful use of the buccal pump. We concluded that the coherence function reveals behaviors that are not apparent through visual inspection of ventilatory time series.

  5. Goal orientation by geometric and feature cues: spatial learning in the terrestrial toad Rhinella arenarum. (United States)

    Sotelo, María Inés; Bingman, Verner Peter; Muzio, Rubén N


    Although of crucial importance in vertebrate evolution, amphibians are rarely considered in studies of comparative cognition. Using water as reward, we studied whether the terrestrial toad, Rhinella arenarum, is also capable of encoding geometric and feature information to navigate to a goal location. Experimental toads, partially dehydrated, were trained in either a white rectangular box (Geometry-only, Experiment 1) or in the same box with a removable colored panel (Geometry-Feature, Experiment 2) covering one wall. Four water containers were used, but only one (Geometry-Feature), or two in geometrically equivalent corners (Geometry-only), had water accessible to the trained animals. After learning to successfully locate the water reward, probe trials were carried out by changing the shape of the arena or the location of the feature cue. Probe tests revealed that, under the experimental conditions used, toads can use both geometry and feature to locate a goal location, but geometry is more potent as a navigational cue. The results generally agree with findings from other vertebrates and support the idea that at the behavioral-level geometric orientation is a conserved feature shared by all vertebrates.

  6. 越南的蟾蜍文化%Vietnamese Toad Culture

    Institute of Scientific and Technical Information of China (English)



    As a kind of animal which is familiar in the farming society and has the very ability of reproducing fast, toad has won the reverences and the worships of people. After thousands of years of history moving and changing, toad became to have abundant philosophy disposition, and bear the weight of the faraway remote antiquity consciousness. Besides, toad also has been blended into the vulgarism, folk song and mythology legend of Vietnam, deeply influencing the everyday language, vocabulary and culture of Vietnamese people.%作为一种以水稻耕作为主的农业社会常见的、具有超强的繁殖能力的动物,蟾蜍成为人们敬畏和崇拜的对象,数千年来的历史变迁,使蟾蜍的形象蕴含着丰富的哲理意向,承载着悠久的远古意识,融入了越南的俗语、民歌、神话传说中,嵌入了人们日常使用的语言、词汇中,形成蟾蜍文化现象。

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

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


    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.

  8. The effect of calcium withdrawal on the structure and function of the toad bladder. (United States)

    Hays, R M; Singer, B; Malamed, S


    Previous reports have indicated that calcium is necessary to support active sodium transport by the toad bladder, and may be required as well in the action of vasopressin on both toad bladder and frog skin. The structure and function of the toad bladder has been studied in the absence of calcium, and a reinterpretation of the previous findings now appears possible. When calcium is withdrawn from the bathing medium, epithelial cells detach from one another and eventually from their supporting tissue. The short-circuit current (the conventional means of determining active sodium transport) falls to zero, and vasopressin fails to exert its usual effect on short-circuit current and water permeability. However, employing an indirect method for the estimation of sodium transport (oxygen consumption), it is possible to show that vasopressin exerts its usual effect on Q(oo2) when sodium is present in the bathing medium. Hence, it appears that the epithelial cells maintain active sodium transport when calcium is rigorously excluded from the bathing medium, and continue to respond to vasopressin. The failure of conventional techniques to show this can be attributed to the structural alterations in the epithelial layer in the absence of calcium. These findings may provide a model for the physiologic action of calcium in epithelia such as the renal tubule.

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


    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

  10. 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)


    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.

  11. Isolation breeds naivety: island living robs Australian varanid lizards of toad-toxin immunity via four-base-pair mutation. (United States)

    Ujvari, Beata; Mun, Hee-chang; Conigrave, Arthur D; Bray, Alessandra; Osterkamp, Jens; Halling, Petter; Madsen, Thomas


    Since their introduction to the toad-free Australian continent cane toads (Bufo marinus) have caused a dramatic increase in naïve varanid mortality when these large lizards attempt to feed on this toxic amphibian. In contrast Asian-African varanids, which have coevolved with toads, are resistant to toad toxin. Toad toxins, such as Bufalin target the H1-H2 domain of the α(1) subunit of the sodium-potassium-ATPase enzyme. Sequencing of this domain revealed identical nucleotide sequences in four Asian as well as in three African varanids, and identical sequences in all 11 Australian varanids. However, compared to the Asian-African varanids, the Australian varanids showed four-base-pair substitutions, resulting in the alteration in three of the 12 amino acids representing the H1-H2 domain. The phenotypic effect of the substitutions was investigated in human embryonic kidney (HEK) 293 cells stably transfected with the Australian and the Asian-African H1-H2 domains. The transfections resulted in an approximate 3000-fold reduction in resistance to Bufalin in the Australian HEK293 cells compared to the Asian-African HEK293 cells, demonstrating the critical role of this minor mutation in providing Bufalin resistance. Our study hence presents a clear link between genotype and phenotype, a critical step in understanding the evolution of phenotypic diversity.

  12. The interacting effects of ungulate hoofprints and predatory native ants on metamorph cane toads in tropical Australia.

    Directory of Open Access Journals (Sweden)

    Elisa Cabrera-Guzmán

    Full Text Available Many invasive species exploit the disturbed habitats created by human activities. Understanding the effects of habitat disturbance on invasion success, and how disturbance interacts with other factors (such as biotic resistance to the invaders from the native fauna may suggest new ways to reduce invader viability. In tropical Australia, commercial livestock production can facilitate invasion by the cane toad (Rhinella marina, because hoofprints left by cattle and horses around waterbody margins provide distinctive (cool, moist microhabitats; nevertheless the same microhabitat can inhibit the success of cane toads by increasing the risks of predation or drowning. Metamorph cane toads actively select hoofprints as retreat-sites to escape dangerous thermal and hydric conditions in the surrounding landscape. However, hoofprint geometry is important: in hoofprints with steep sides the young toads are more likely to be attacked by predatory ants (Iridomyrmex reburrus and are more likely to drown following heavy rain. Thus, anthropogenic changes to the landscape interact with predation by native taxa to affect the ability of cane toads in this vulnerable life-history stage to thrive in the harsh abiotic conditions of tropical Australia.

  13. Foraging modality and plasticity in foraging traits determine the strength of competitive interactions among carnivorous plants, spiders and toads. (United States)

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


    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.

  14. 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.

  15. Geology and mammalian paleontology of the Horned Toad Hills, Mojave Desert, California, USA (United States)

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


    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.

  16. Two novel antimicrobial peptides from skin venoms of spadefoot toad Megophrys minor. (United States)

    Yang, Hong-Ling; Shen, Zhi-Qiang; Liu, Xuan; Kong, Yi


    Amphibian skin contains rich bioactive peptides. Especially, a large amount of antimicrobial peptides have been identified from amphibian skin secretions. Antimicrobial peptides display potent cytolytic activities against a range of pathogenic bacteria and fungi and play important defense roles. No antimicrobial peptides have been reported from toads belonging to the family of Pelobatidae. In this work, two novel antimicrobial peptides (Megin 1 and Megin 2) were purified and characterized from the skin venoms of spadefoot toad Megophrys minor (Pelobatidae, Anura, Amphibia). Megin 1 had an amino acid sequence of FLKGCWTKWYSLKPKCPF-NH2, which was composed of 18 amino acid residues and contained an intra-molecular disulfide bridge and an amidated C-terminus. Megin 2 had an amino acid sequence of FFVLKFLLKWAGKVGLEHLACKFKNWC, which was composed of 27 amino acid residues and contained an intra-molecular disulfide bridge. Both Megin 1 and Megin 2 showed potential antimicrobial abilities against bacteria and fungi. The MICs of Megin 1 against Escherichia coli, Bacillus dysenteriae, Staphylococcus aureus, Bacillus subtilis, and Candida albicans were 25, 3, 6.25, 3, and 50 μg·mL(-1), respectively. The corresponding MICs for Megin 2 were 6.25, 1.5, 12.5, 1.5, and 12.5 μg·mL(-1), respectively. They also exerted strong hemolytic activity against human and rabbit red cells. The results suggested that megin peptides in the toad skin of M. minor displayed toxic effects on both eukaryotes and prokaryotes. This was the first report of antimicrobial peptides from amphibians belonging to the family of Pelobatidae.

  17. 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


    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.

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

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


    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.

  19. 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


    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...

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

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


    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.

  1. Biomarker analysis of American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles following exposure to atrazine. (United States)

    The objective of the current study was to use a biomarker-based approach to investigate the influence of atrazine exposure on American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles. Atrazine is one of the most frequently detected herbicides in environme...

  2. Morphological and allozyme studies of midwife toads (genus Alytes), including the description of two new taxa from Spain

    NARCIS (Netherlands)

    Arntzen, J.W.; García-París, M.


    Allozyme variation in 31 to 50 presumptive loci of 12 populations of European midwife toads of the genus Alytes show appreciable genetic divergences (DiNe from 0.29 to 0.72) among four groups. These groups correspond to A. cisternasii Boscá, 1879, A. obstetricans (Laurenti, 1768), A. muletensis (San

  3. The status and relationships of some East African Earless Toads (Anura, Bufonidae) with a description of a new species

    NARCIS (Netherlands)

    Grandison, A.G.C.


    INTRODUCTION In comparing some small Ethiopian Bufo with the descriptions, types and other examples of numerous forms from East and Central African countries I became very much aware of the confusion that exists in the taxonomy and of the need for a revision of this group of dwarf toads. Most of the

  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.


    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. 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


    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 ].

  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


    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...

  7. Toxin-resistant isoforms of Na+/K+-ATPase in snakes do not closely track dietary specialization on toads. (United States)

    Mohammadi, Shabnam; Gompert, Zachariah; Gonzalez, Jonathan; Takeuchi, Hirohiko; Mori, Akira; Savitzky, Alan H


    Toads are chemically defended by bufadienolides, a class of cardiotonic steroids that exert toxic effects by binding to and disabling the Na(+)/K(+)-ATPases of cell membranes. Some predators, including a number of snakes, have evolved resistance to the toxic effects of bufadienolides and prey regularly on toads. Resistance in snakes to the acute effects of these toxins is conferred by at least two amino acid substitutions in the cardiotonic steroid binding pocket of the Na(+)/K(+)-ATPase. We surveyed 100 species of snakes from a broad phylogenetic range for the presence or absence of resistance-conferring mutations. We found that such mutations occur in a much wider range of taxa than previously believed. Although all sequenced species known to consume toads exhibited the resistance mutations, many of the species possessing the mutations do not feed on toads, much less specialize on that food source. This suggests that either there is little performance cost associated with these mutations or they provide an unknown benefit. Furthermore, the distribution of the mutation among major clades of advanced snakes suggests that the origin of the mutation reflects evolutionary retention more than dietary constraint.

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

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


    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.

  9. Melanophryniscus montevidensis (Philippi, 1902 (Anura: Bufonidae

    Directory of Open Access Journals (Sweden)

    Tedros, Marcelo


    Full Text Available Brasil, Estado de Rio Grande do Sul, Alvorada, Barra do Chui, 33°45'S 53°16' W. Febrero de 1989. Colector: M. Tedros. (Colección de Batracios de la Secci ón Zoología Vertebrados de la Facultad de Ciencias de la Universidad de la República, Uruguay ZVCB 7276, ZVCB 7277 y ZVCB 7278.

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

    Institute of Scientific and Technical Information of China (English)


    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 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.

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

    Institute of Scientific and Technical Information of China (English)


    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.


    CHOI, J K


    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.

  13. Indirect evidence for elastic energy playing a role in limb recovery during toad hopping. (United States)

    Schnyer, Ariela; Gallardo, Mirialys; Cox, Suzanne; Gillis, Gary


    Elastic energy is critical for amplifying muscle power during the propulsive phase of anuran jumping. In this study, we use toads (Bufo marinus) to address whether elastic recoil is also involved after take-off to help flex the limbs before landing. The potential for such spring-like behaviour stems from the unusually flexed configuration of a toad's hindlimbs in a relaxed state. Manual extension of the knee beyond approximately 90° leads to the rapid development of passive tension in the limb as underlying elastic tissues become stretched. We hypothesized that during take-off, the knee regularly extends beyond this, allowing passive recoil to help drive limb flexion in mid-air. To test this, we used high-speed video and electromyography to record hindlimb kinematics and electrical activity in a hindlimb extensor (semimembranosus) and flexor (iliofibularis). We predicted that hops in which the knees extended further during take-off would require less knee flexor recruitment during recovery. Knees extended beyond 90° in over 80% of hops, and longer hops involved greater degrees of knee extension during take-off and more intense semimembranosus activity. However, knee flexion velocities during recovery were maintained despite a significant decrease in iliofibularis intensity in longer hops, results consistent with elastic recoil playing a role.

  14. Functional assessment of toad parotoid macroglands: a study based on poison replacement after mechanical compression. (United States)

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


    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.

  15. Membrane potential plays a dual role for chloride transport across toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Rasmussen, B E


    The Cl- -current through toad skin epithelium depends on the potential in a way consistent with a potential-controlled Cl- permeability. Computer analysis of the Koefoed-Johnsen Ussing two-membrane model provided with constant membrane permeabilities indicates that the voltage- and time-dependent......The Cl- -current through toad skin epithelium depends on the potential in a way consistent with a potential-controlled Cl- permeability. Computer analysis of the Koefoed-Johnsen Ussing two-membrane model provided with constant membrane permeabilities indicates that the voltage- and time......-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...... resemble experimental observations. This extension of the classic frog skin model implies that the Cl- permeability is activated by a voltage change caused by the inward Na+ current through the apical membrane....

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

    Directory of Open Access Journals (Sweden)

    Juliana Mozer Sciani


    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.

  17. 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


    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.

  18. 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.

  19. Seasonal dynamics of the lungworm, Rhabdias pseudosphaerocephala, in recently colonised cane toad (Rhinella marina) populations in tropical Australia. (United States)

    Pizzatto, Lígia; Kelehear, Crystal; Shine, Richard


    The impact of parasites on host populations depend upon parasite prevalence and intensity. Understanding how infection dynamics change through time following a host population's initial exposure to the parasite is fundamental to host-parasite biology. We studied an invasive host (the cane toad, Rhinella marina) currently undergoing range expansion - a process through which this host's range is expanding faster than that of its lung parasites (the nematode, Rhabdias pseudosphaerocephala), such that hosts at the expanding range edge remain parasite-free for several years. It was predicted that parasite intensity and prevalence would be affected by host characteristics (e.g., size, sex), environmental conditions (e.g., seasons, habitat type), and time since parasite arrival in the newly established invading host population. Over 2,400 cane toads were sampled at 10 sites in recently established toad populations in the highly seasonal monsoonal tropics of northern Australia. The sampling spanned 14 consecutive 3 month seasons commencing in the early stages of lungworm establishment in those toad populations. Both parasite prevalence and intensity increased with host body size but were unaffected by host sex. Prevalence and intensity were highest during drier times of year and in drier habitats (i.e., sites lacking permanent waterbodies). These changes in parasite prevalence may reflect a trend for saturated soil to reduce parasite survival during the free-living infective stage, and to allow anuran hosts to disperse widely (thus reducing the transfer of directly transmitted parasites between hosts). Conversely, dry conditions induce toads to aggregate in moist dry-season refugia where conditions may be more conducive to direct transmission of infective parasitic larvae between hosts.

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

  1. CRED Optical Validation Data at the islands of Ofu and Olosega in American Samoa, 2004 to Support Benthic Habitat Mapping (TOAD) (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...

  2. CRED Optical Validation Data at the island of Ta'u in American Samoa, 2006 to support Benthic Habitat Mapping (TOAD) (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...

  3. Glycogen stability and glycogen phosphorylase activities in isolated skeletal muscles from rat and toad. (United States)

    Goodman, C A; Stephenson, G M


    There is increasing evidence that endogenous glycogen depletion may affect excitation-contraction (E-C) coupling events in vertebrate skeletal muscle. One approach employed in physiological investigations of E-C coupling involves the use of mechanically skinned, single fibre preparations obtained from tissues stored under paraffin oil, at room temperature (RT: 20-24 degrees C) and 4 degrees C for several hours. In the present study, we examined the effect of these storage conditions on the glycogen content in three muscles frequently used in research on E-C coupling: rat extensor digitorum longus (EDL) and soleus (SOL) and toad iliofibularis (IF). Glycogen content was determined fluorometrically in homogenates prepared from whole muscles, stored under paraffin oil for up to 6 h at RT or 4 degrees C. Control muscles and muscles stored for 0.5 and 6 h were also analysed for total phosphorylase (Phos(total)) and phosphorylase a (Phos a) activities. No significant change was observed in the glycogen content of EDL and SOL muscles stored at RT for 0.5 h. In rat muscles stored at RT for longer than 0.5 h, the glycogen content decreased to 67.6% (EDL) and 78.7% (SOL) of controls after 3 h and 25.3% (EDL) and 37.4% (SOL) after 6 h. Rat muscles stored at 4 degrees C retained 79.0% (EDL) and 92.5% (SOL) of glycogen after 3 h and 75.2% (EDL) and 61.1% (SOL) after 6 h. The glycogen content of IF muscles stored at RT or 4 degrees C for 6 h was not significantly different from controls. Phos(total) was unchanged in all muscles over the 6 h period, at both temperatures. Phos a was also unchanged in the toad IF muscles, but in rat muscles it decreased rapidly, particularly in EDL (4.1-fold after 0.5 h at RT). Taken together these results indicate that storage under paraffin oil for up to 6 h at RT or 4 degrees C is accompanied by minimal glycogen loss in toad IF muscles and by a time- and temperature-dependent glycogen loss in EDL and SOL muscles of the rat.

  4. 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


    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

  5. 汉画蟾蜍图像源考及其象征意义%Toad Image Source in Han Dynasty Paintings and Symbolic Meaning

    Institute of Scientific and Technical Information of China (English)



    There are a large volume of images of toad in the paintings of Han Dynasty, basically two types. One type is toad symbolizing the moon. Since the history of toads as the "moon spirit" is long with variations there are mistakes as well as misunderstandings. Another type is toads as part of the West fairy q.ueen' s fairy land. From the view of iconography and archetypal criticism ,the study aims to clarify the developing line of the relation between toads and the moon as well as the symbolic meaning of toads in the West fairy queen' s fairy land.%汉代的画像艺术中存在着大量蟾蜍图像,这些图像大致可分为两类:一是作为月亮的代表。蟾蜍成为“月精”的历史久远且多有变动,因此造成一些讹误;二是作为西王母仙境的组成部分。文章运用图像学和原型批评方法,旨在厘清蟾月关系的发展脉络及蟾蜍在汉画西王母仙境中的象征意义。


    Institute of Scientific and Technical Information of China (English)

    高云芳; 樊小力


    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.

  7. Advancement in research of anti-cancer effects of toad venom (ChanSu) and perspectives

    Institute of Scientific and Technical Information of China (English)

    Miao Liu; Li-Xing Feng; Li-Hong Hu; Xuan Liu; De-An Guo


    Toad venom, called as ChanSu in China, is a widely used traditional Chinese medicine (TCM) whose active components are mainly bufadienolides. ChanSu could exhibit cardiotonic, anti-microbial, anti-inflammatory and, most importantly, anti-cancer effects. In the present review, reports about the in vitro, in vivo and clinical anti-cancer effects of ChanSu or its representative component, bufalin, were summarized. And, reported anti-cancer mechanisms of cardenolides, structure analogues of bufadienolides, were also introduced. Based on the results got from research of ChanSu/bufalin and the results from cardenolides, possible signal network related to the anti-cancer effects of ChanSu/bufalin was predicted. Furthermore, future potential use of ChanSu in anti-cancer therapy was discussed.

  8. Evolution of rapid development in spadefoot toads is unrelated to arid environments. (United States)

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


    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.

  9. All-optical repetition rate multiplication of pseudorandom bit sequences based on cascaded TOADs (United States)

    Sun, Zhenchao; Wang, Zhi; Wu, Chongqing; Wang, Fu; Li, Qiang


    A scheme for all-optical repetition rate multiplication of pseudorandom bit sequences (PRBS) is demonstrated with all-optical wavelength conversion and optical logic gate 'OR' based on cascaded Tera-Hertz Optical Asymmetric Demultiplexers (TOADs). Its feasibility is verified by multiplication experiments from 500 Mb/s to 4 Gb/s for 23-1 PRBS and from 1 Gb/s to 4 Gb/s for 27-1 PRBS. This scheme can be employed for rate multiplication for much longer cycle PRBS at much higher bit rate over 40 Gb/s when the time-delay, the loss and the dispersion of the optical delay line are all precisely managed. The upper limit of bit rate will be restricted by the recovery time of semiconductor optical amplifier (SOA) finally.

  10. 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


    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.

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

    Sinsch, Ulrich; Schäfer, Alena M


    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.

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


    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

  13. 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.

  14. Bm-TFF2, a toad trefoil factor, promotes cell migration, survival and wound healing. (United States)

    Zhang, Yong; Yu, Guoyu; Xiang, Yang; Wu, Jianbo; Jiang, Ping; Lee, Wenhui; Zhang, Yun


    Toad skin is naked and continually confronted by various injurious factors. Constant skin renewal and repairs occur frequently. However, the mechanisms of the renewal and repair have not clearly elucidated. In our previous work, a trefoil factor (TFF), Bm-TFF2, has been purified from the Bombina maxima skin and characterized as a platelet agonist. The mRNA of TFFs in toad skin was up-regulated greatly during the metamorphosis, indicating a pivotal role of TFFs in amphibian skin. Here, we presented the effects of Bm-TFF2 on the cell migration, apoptosis and proliferation. Bm-TFF2 bound to epithelial cells and showed strong cell motility activity. At the concentrations of 1-100nM, Bm-TFF2-induced migration of human epithelial AGS and HT-29 cells, and rat intestinal epithelial IEC-6 cell lines. The in vitro wound healing assay also verified the activity of Bm-TFF2. Bm-TFF2 could also inhibit cell apoptosis induced by ceramide and sodium butyrate. The cell migration-promoting activity was abolished by MEK1 inhibitors, U0126 and PD98059, suggesting that ERK1/2 activation is crucial for Bm-TFF2 to stimulate cell migration. Taken together, Bm-TFF2 promoted wound healing by stimulating cell migration via MAPK pathway and preventing cell apoptosis. The potent biological activity of Bm-TFF2 makes it a useful molecular tool for further studies of structure-function relationship of the related human TFFs.

  15. Absence of the trade-off between the size and number of offspring in the natterjack toad (Bufo calamita)



    A trade-off between size and number of offspring was not found for females of similar sizes of the natterjack toad (Bufo calamita). Moreover, for large females, clutches with higher number of eggs had larger eggs as well. This suggests that larger females produce more numerous and larger eggs because they potentially have more energy available for reproduction. Egg size diminished allometrically with clutch size. Egg size, however, did not increase offspring fitness. Therefore, this allometri...

  16. Tubular system volume changes in twitch fibres from toad and rat skeletal muscle assessed by confocal microscopy. (United States)

    Launikonis, Bradley S; Stephenson, D George


    The volume of the extracellular compartment (tubular system) within intact muscle fibres from cane toad and rat was measured under various conditions using confocal microscopy. Under physiological conditions at rest, the fractional volume of the tubular system (t-sys(Vol)) was 1.38 +/- 0.09 % (n = 17), 1.41 +/- 0.09 % (n = 12) and 0.83 +/- 0.07 % (n = 12) of the total fibre volume in the twitch fibres from toad iliofibularis muscle, rat extensor digitorum longus muscle and rat soleus muscle, respectively. In toad muscle fibres, the t-sys(Vol) decreased by 30 % when the tubular system was fully depolarized and decreased by 15 % when membrane cholesterol was depleted from the tubular system with methyl-beta-cyclodextrin but did not change as the sarcomere length was changed from 1.93 to 3.30 microm. There was also an increase by 30 % and a decrease by 25 % in t-sys(Vol) when toad fibres were equilibrated in solutions that were 2.5-fold hypertonic and 50 % hypotonic, respectively. When the changes in total fibre volume were taken into consideration, the t-sys(Vol) expressed as a percentage of the isotonic fibre volume did actually decrease as tonicity increased, revealing that the tubular system in intact fibres cannot be compressed below 0.9 % of the isotonic fibre volume. The results can be explained in terms of forces acting at the level of the tubular wall. These observations have important physiological implications showing that the tubular system is a dynamic membrane structure capable of changing its volume in response to the membrane potential, cholesterol depletion and osmotic stress but not when the sarcomere length is changed in resting muscle.

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


    Hanner, R H; Ryan, G B


    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...

  18. 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


    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].

  19. Effect of nifedipine on depolarization-induced force responses in skinned skeletal muscle fibres of rat and toad. (United States)

    Posterino, G S; Lamb, G D


    The effect of the dihydropyridine, nifedipine, on excitation-contraction coupling was compared in toad and rat skeletal muscle, using the mechanically skinned fibre technique, in order to understand better the apparently disparate results of previous studies and to examine recent proposals on the importance of certain intracellular factors in determining the efficacy of dihydropyridines. In twitch fibres from the iliofibularis muscle of the toad, 10 microM nifedipine completely inhibited depolarization-induced force responses within 30 s, without interfering with direct activation of the Ca(2+)-release channels by caffeine application or reduction of myoplasmic [Mg2+]. At low concentrations of nifedipine, inhibition was considerably augmented by repeated depolarizations, with half-maximal inhibition occurring at < 0.1 microM nifedipine. In contrast, in rat extensor digitorum longus (EDL) fibres 1 microM nifedipine had virtually no effect on depolarization-induced force responses, and 10 microM nifedipine caused only approximately 25% reduction in the responses, even upon repeated depolarizations. In rat fibres, 10 microM nifedipine shifted the steady-state force inactivation curve to more negative potentials by < 11 mV, whereas in toad fibres the potent inhibitory effect of nifedipine indicated a much larger shift. The inhibitory effect of nifedipine in rat fibres was little, if at all, increased by the absence of Ca2+ in the transverse tubular (t-) system, provided that the Ca2+ was replaced with sufficient Mg2+. The presence of the reducing agents dithiothreitol (10 mM) or glutathione (10 mM) in the solution bathing a toad skinned fibre did not reduce the inhibitory effect of nifedipine, suggesting that the potency of nifedipine in toad skinned fibres was not due to the washout of intracellular reducing agents. The results are considered in terms of a model that can account for the markedly different effects of nifedipine on the two putative functions of the

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

    Directory of Open Access Journals (Sweden)

    Luciana Sonne


    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.

  1. New species of beaked toad, Rhinella (Anura: Bufonidae, from the State of Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Ulisses Caramaschi


    Full Text Available A new species of beaked toad, Rhinella, is described from Itacaré (14°17'S, 38°60'W; 13 m altitude, State of Bahia, Northeastern Brazil. Rhinella skuki sp. nov. is related to R. boulengeri and distinguished by the size small (SVL 26.2 mm in male; head longer than wide; snout, viewed from above, long, narrow, spatulate, with lateral borders parallel and rounded tip; in profile, long, strongly acute; parotoid glands large, rounded; tympanum concealed; dorsum rugose, with rounded tubercles uniformly distributed; vocal sac and vocal slits absent; fingers slender, not webbed nor ridged; first finger hypertrophied, with a rounded nuptial pad on the inner surface; toes slender, slightly fringed; webbing absent; ground color of dorsal surfaces dark brownish gray with an interorbital bar and dorsolateral blotches clear brownish gray, leaving an apparent pattern of arrows on dorsum; venter and ventral surfaces of arms and thighs cream with diffuse gray stains and dots; gular region and chest dark brownish gray.

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

    Institute of Scientific and Technical Information of China (English)


    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.

  3. 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)



    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.

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

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    S. A. Sakr


    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.

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

    Directory of Open Access Journals (Sweden)

    J.E.S. Natali


    Full Text Available 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 P<0.01. These results indicate that R. jimi has a lower thermal 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.

  6. Analysis of heart rate control to assess thermal sensitivity responses in Brazilian toads. (United States)

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


    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 P<0.01). These results indicate that R. jimi has a lower thermal 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.

  7. Effects of diltiazem on skinned skeletal muscle fibers of the African clawed toad. (United States)

    Ishizuka, T; Endo, M


    To examine the effects of diltiazem and its l-cis isomer (which possesses only a weak Ca++-antagonistic action) on the contractile system and the sarcoplasmic reticulum of skeletal muscle, we used skinned fibers isolated from iliofibularis muscle of the African clawed toad, Xenopus laevis. Diltiazem showed the following effects: an increase in the Ca++ sensitivity of the contractile system, a decrease in the maximal tension developed in a saturating concentration of Ca++, an inhibition of Ca++ uptake by the sarcoplasmic reticulum, an inhibition of Ca++ release from the sarcoplasmic reticulum by caffeine, and an increase in the Ca++ permeability of the sarcoplasmic reticulum membrane. The effects of the l-cis isomer were similar to those of diltiazem, and the potencies of the two substances were nearly equal, except with respect to the effect on the Ca++ release induced by caffeine: the l-cis isomer potentiated this type of Ca++ release. Diltiazem's effects on amphibian skinned skeletal muscle fibers may not be related qualitatively or quantitatively to the Ca++-antagonistic actions of the drug on mammalian cardiac and smooth muscles. The pharmacological spectrum of diltiazem on skinned skeletal muscle fibers is similar to that of some local anesthetics.

  8. A maternal effect mediates rapid population divergence and character displacement in spadefoot toads. (United States)

    Pfennig, David W; Martin, Ryan A


    Despite long-standing interest in character displacement, little is known of its underlying proximate causes. Here, we explore the role of maternal effects in character displacement. We specifically investigated whether differences in maternal body condition mediate divergence in the expression of resource-use traits between populations of spadefoot toads (Spea multiplicata) that occur in sympatry with a heterospecific competitor and those that occur in allopatry. In sympatry, S. multiplicata is forced by its competitor onto a less profitable resource. As a result, sympatric females mature in poorer condition and invest less into offspring. Consequently, their offspring produce a resource-use phenotype that minimizes competition with the other species and that also differs from the phenotype produced in allopatry. These differences in trait expression between allopatry and sympatry disappear once mothers are equilibrated in body condition in the laboratory. Thus, a condition-dependent maternal effect mediates population divergence and character displacement. Such effects potentially buffer populations from extinction (via competitive exclusion) while genetic changes accumulate, which produce divergent traits in the absence of the maternal effect. Maternal effects may therefore often be important in determining the initial direction and rate of evolution during the early stages of character displacement.

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

    Vincent, Kim; Davidson, Carlos


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

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


    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.

  11. Vocalizations in juvenile anurans: common spadefoot toads (Pelobates fuscus) regularly emit calls before sexual maturity. (United States)

    Ten Hagen, Leonie; Rodríguez, Ariel; Menke, Norbert; Göcking, Christian; Bisping, Michael; Frommolt, Karl-Heinz; Ziegler, Thomas; Bonkowski, Michael; Vences, Miguel


    Acoustic communication is prominent in adult anuran amphibians, in reproductive, territorial and defensive contexts. In contrast, reports on vocalizations of juvenile anurans are rare and anecdotal, and their function unstudied. We here provide conclusive evidence for vocalizations in juvenile spadefoot toads (Pelobates fuscus) in very early terrestrial stages. While the aquatic tadpoles did not emit sounds, first vocalizations of metamorphs were heard as early as in stages 42-43, and calls were regularly emitted from stage 44 on, often from specimens still bearing extensive tail stubs. Three main types of calls could be distinguished, of which one consists of a series of short notes, one of a typically single longer and pulsed note, and one of a single tonal note. In experimental setups, the number of calls per froglet increased with density of individuals and after feeding, while on the contrary calls were not elicited by playback. The function of these juvenile calls remains unclarified, but they might reflect a general arousal in the context of feeding. Further evidence is necessary to test whether such feeding calls could confer a signal to conspecifics and thus might represent intraspecific acoustic communication in these immature terrestrial amphibians.

  12. Buforins: histone H2A-derived antimicrobial peptides from toad stomach. (United States)

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


    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.

  13. Effects of inhibition gastric acid secretion on arterial acid-base status during digestion in the toad Bufo marinus. (United States)

    Andersen, Johnnie B; Andrade, Denis V; Wang, Tobias


    Digestion affects acid-base status, because the net transfer of HCl from the blood to the stomach lumen leads to an increase in HCO3(-) levels in both extra- and intracellular compartments. The increase in plasma [HCO3(-)], the alkaline tide, is particularly pronounced in amphibians and reptiles, but is not associated with an increased arterial pH, because of a concomitant rise in arterial PCO2 caused by a relative hypoventilation. In this study, we investigate whether the postprandial increase in PaCO2 of the toad Bufo marinus represents a compensatory response to the increased plasma [HCO3(-)] or a state-dependent change in the control of pulmonary ventilation. To this end, we successfully prevented the alkaline tide, by inhibiting gastric acid secretion with omeprazole, and compared the response to that of untreated toads determined in our laboratory during the same period. In addition, we used vascular infusions of bicarbonate to mimic the alkaline tide in fasting animals. Omeprazole did not affect blood gases, acid-base and haematological parameters in fasting toads, but abolished the postprandial increase in plasma [HCO3(-)] and the rise in arterial PCO2 that normally peaks 48 h into the digestive period. Vascular infusion of HCO3(-), that mimicked the postprandial rise in plasma [HCO3(-)], led to a progressive respiratory compensation of arterial pH through increased arterial PCO2. Thus, irrespective of whether the metabolic alkalosis is caused by gastric acid secretion in response to a meal or experimental infusion of bicarbonate, arterial pH is being maintained by an increased arterial PCO2. It seems, therefore, that the elevated PCO2, occuring during the postprandial period, constitutes of a regulated response to maintain pH rather than a state-dependent change in ventilatory control.

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

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


    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

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


    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

  16. Electrophysiological properties of the tongue epithelium of the toad Bufo marinus. (United States)

    Baker, Timothy K; Rios, Karina; Hillyard, Stanley D


    The dorsal lingual epithelium from the tongue of the toad Bufo marinus was mounted in an Ussing-type chamber, and the short-circuit current (I(sc)) was measured using a low-noise voltage clamp. With NaCl Ringer bathing the mucosal and serosal surfaces of the isolated tissue, an outwardly directed (mucosa-positive) I(sc) was measured that averaged -10.71+/-0.82 microA cm(-2) (mean +/- S.E.M., N=24) with a resistance of 615+/-152 Omega cm(2) (mean +/- S.E.M., N=10). Substitution of chloride with sulfate as the anion produced no significant change in I(sc). Fluctuation analysis with either NaCl or Na(2)SO(4) Ringer bathing both sides of the tissue revealed a spontaneous Lorentzian component, suggesting that the I(sc) was the result of K(+) secretion through spontaneously fluctuating channels in the apical membrane of the epithelium. This hypothesis was supported by the reversible inhibition of I(sc) by Ba(2+) added to the mucosal Ringer. Analysis of the kinetics of Ba(2+) inhibition of I(sc) indicates that there might be more than one type of K(+) channel carrying the I(sc). This hypothesis was supported by power spectra obtained with a serosa-to-mucosa K(+) gradient, which could be fitted to two Lorentzian components. At present, the K(+) secretory current cannot be localized to taste cells or other cells that might be associated with the secretion of saliva or mucus. Nonetheless, the resulting increase in [K(+)] in fluid bathing the mucosal surface of the tongue could presumably affect the sensitivity of the taste cells. These results contrast with those from the mammalian tongue, in which a mucosa-negative I(sc) results from amiloride-sensitive Na(+) transport.

  17. Phylogeography of the fire-bellied toads Bombina: independent Pleistocene histories inferred from mitochondrial genomes. (United States)

    Hofman, Sebastian; Spolsky, Christina; Uzzell, Thomas; Cogălniceanu, Dan; Babik, Wiesław; Szymura, Jacek M


    The fire-bellied toads Bombina bombina and Bombina variegata, interbreed in a long, narrow zone maintained by a balance between selection and dispersal. Hybridization takes place between local, genetically differentiated groups. To quantify divergence between these groups and reconstruct their history and demography, we analysed nucleotide variation at the mitochondrial cytochrome b gene (1096 bp) in 364 individuals from 156 sites representing the entire range of both species. Three distinct clades with high sequence divergence (K2P = 8-11%) were distinguished. One clade grouped B. bombina haplotypes; the two other clades grouped B. variegata haplotypes. One B. variegata clade included only Carpathian individuals; the other represented B. variegata from the southwestern parts of its distribution: Southern and Western Europe (Balkano-Western lineage), Apennines, and the Rhodope Mountains. Differentiation between the Carpathian and Balkano-Western lineages, K2P approximately 8%, approached interspecific divergence. Deep divergence among European Bombina lineages suggests their preglacial origin, and implies long and largely independent evolutionary histories of the species. Multiple glacial refugia were identified in the lowlands adjoining the Black Sea, in the Carpathians, in the Balkans, and in the Apennines. The results of the nested clade and demographic analyses suggest drastic reductions of population sizes during the last glacial period, and significant demographic growth related to postglacial colonization. Inferred history, supported by fossil evidence, demonstrates that Bombina ranges underwent repeated contractions and expansions. Geographical concordance between morphology, allozymes, and mtDNA shows that previous episodes of interspecific hybridization have left no detectable mtDNA introgression. Either the admixed populations went extinct, or selection against hybrids hindered mtDNA gene flow in ancient hybrid zones.

  18. Age structure, growth and longevity in the common toad, Rhinella arenarum, from Argentina

    Directory of Open Access Journals (Sweden)

    Clarisa de L. Bionda


    Full Text Available Age structure, growth and longevity was determined in the common toad, Rhinella arenarum, from a suburban pond located in the Pampa plains, central Argentina during two breeding seasons, in 2000 and 2008 by using skeletochronology, which relies on the analysis of the annual lines of arrested growth (LAGs in bones. Both females and males were captured in 2008, while only males were recorded in 2000. Females were significantly larger than males. Mean population age was 2.4 ± 0.9 years in 2000. In 2008, the difference in age was not significant between the sexes (Males: 3.0 ± 0.7, n = 21; Females: 2.6 ± 0.9, n = 12, neither between males in 2000 and 2008. The longevity in males of 2000 was 6 LAGs and exceeded that of males (5 LAGs and females (4 LAGs in 2008. Von Bertalanffy curves showed that the growth coefficient in the males of 2000 (K = 2.97 ± 0.47 was almost double that of females (K = 1.21 ± 0.10 and males (K = 1.01 ± 0.14 of 2008. Males and females Rhinella arenarum show different morphological and life history traits and the year of sampling can significantly influence the estimation of the studied parameters such as age at maturity and growth rates.

  19. Spatial and temporal ecology of eastern spadefoot toads on a Florida landscape.

    Energy Technology Data Exchange (ETDEWEB)

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


    Effective amphibian conservation must consider population and landscape processes, but information at multiple scales is rare. We explore spatial and temporal patterns of breeding and recruitment by Eastern Spadefoot Toads (Scaphiopus holbrookii), using 9 years of data from continuous monitoring with drift fences and pitfall traps at 8 ephemeral ponds in longleaf pine-wiregrass sandhills. Breeding events (>25 adults at a pond within a month) occurred 23 times on nine occasions at seven of the eight study ponds, but substantial recruitment(>100 metamorphs) followed only five events. Recruitment ranged from 0-4,648 among ponds. Only four ponds functioned as population ''sources'', but only during some years. The other ponds, and even ''source'' ponds during some years, functioned either as ''sinks'', where breeding occurred with no resulting recruitment, or were not used at all for breeding. Most recruitment occurred during four years. Recruitment was correlated with adult breeding effort, but only during some years. Recaptures were rare, and inter-pond exchange of adults was minimal and short-distance (< 130 m; 1 was 416 m). Most (83.5%) individuals captured were metamorphs, and 15.9% were > 51 mm (est. > 4 years). We conservatively estimated a 7-year lifespan. Adult ''population'' trends clearly reflected breeding effort rather than numbers per se; capture rates fluctuated dramatically among years, but showed no overall trends during the 9-year study. Our paper provides empiracle information that can be used to generate realistic metapopulation models for S. holbrookii as a tool in conservation planning.

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

    DEFF Research Database (Denmark)

    Allentoft, Morten E.; Siegismund, Hans Redlef; Briggs, Lars;


    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...

  1. 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.


    Incorporation of (32P) phosphate and (14C) acetate into frog (Rana temporaria) skin phospholipids in vitro was positively correlated to skin MR cell density. Transport across toad (Bufo bufo) skin and incorporation into skin phospholipids of the radioactive tracers were independent of transepithe...

  2. Quantifying anuran microhabitat use to infer the potential for parasite transmission between invasive cane toads and two species of Australian native frogs. (United States)

    Pizzatto, Lígia; Both, Camila; Shine, Richard


    Parasites that are carried by invasive species can infect native taxa, with devastating consequences. In Australia, invading cane toads (Rhinella marina) carry lungworm parasites (Rhabdias pseudosphaerocephala) that (based on previous laboratory studies) can infect native treefrogs (Litoria caerulea and L. splendida). To assess the potential of parasite transmission from the invader to the native species (and from one infected native frog to another), we used surveys and radiotelemetry to quantify anuran microhabitat use, and proximity to other anurans, in two sites in tropical Australia. Unsurprisingly, treefrogs spent much of their time off the ground (especially by day, and in undisturbed forests) but terrestrial activity was common at night (especially in anthropogenically modified habitats). Microhabitat overlap between cane toads and frogs was generally low, except at night in disturbed areas, whereas overlap between the two frog species was high. The situations of highest overlap, and hence with the greatest danger of parasite transmission, involve aggregations of frogs within crevices by day, and use of open ground by all three anuran species at night. Overall, microhabitat divergence between toads and frogs should reduce, but not eliminate, the transmission of lungworms from invasive toads to vulnerable native frogs.

  3. Contrasting patterns of quantitative and neutral genetic variation in locally adapted populations of the natterjack toad, Bufo calamita. (United States)

    Gomez-Mestre, Ivan; Tejedo, Miguel


    The relative importance of natural selection and genetic drift in determining patterns of phenotypic diversity observed in nature is still unclear. The natterjack toad (Bufo calamita) is one of a few amphibian species capable of breeding in saline ponds, even though water salinity represents a considerable stress for them. Results from two common-garden experiments showed a pattern of geographic variation in embryonic salinity tolerance among populations from either fresh or brackish environments, consistent with the hypothesis of local adaptation. Full-sib analysis showed increased variation in survival among sibships within population for all populations as osmotic stress was increased (broad-sense heritability increased as salinity raised). Nevertheless, toads native to the brackish water environment had the highest overall survival under brackish conditions. Levels of population genetic differentiation for salinity tolerance were higher than those of neutral genetic differentiation, the latter obtained through the analysis of eight microsatellite loci. Microsatellite markers also revealed little population differentiation, lack of an isolation-by-distance pattern, and moderate gene flow connecting the populations. Therefore, environmental stress tolerance appears to have evolved in absence of geographic isolation, and consequently we reject the null hypothesis of neutral differentiation.

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

    Arendt, Jeffrey David


    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.

  5. Acute toxicity of arsenic and oxidative stress responses in the embryonic development of the common South American toad Rhinella arenarum. (United States)

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


    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.

  6. 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


    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...


    Institute of Scientific and Technical Information of China (English)

    毛驰; 王翰章


    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.

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


    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%) were parasitized by 1 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 2 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. dissimilewas significantly more abundant during the dry season.

  9. The effect of supplementation with vitamin A on serum and liver concentrations in Puerto Rican crested toads (Peltophryne lemur) and its lack of impact on brown skin disease. (United States)

    Dutton, Christopher; Lentini, Andrew; Berkvens, Charlene; Crawshaw, Graham


    "Brown skin disease" (BSD) is a clinical syndrome of dysecdysis, chronic weight loss and death, previously reported in Puerto Rican crested toads (Peltophryne lemur). Although vitamin A deficiency has been suggested, its cause remains unknown and multiple treatments have failed to prevent or reverse the condition. This study compared the efficacy of vitamin A supplementation, administered in different forms and by different routes, in 48 captive born Puerto Rican crested toads fed from metamorphosis on gut-loaded, dusted, commercially raised crickets. Forty-five toads started to show clinical signs of BSD at 9 months of age; all toads were treated orally with an oil-based vitamin A formulation twice weekly for 2 months but continued to deteriorate. Two treatment groups were then compared: Animals in one group (n=19) received 2 IU injectable vitamin A (Aquasol-A) per gram bodyweight subcutaneously twice weekly for 3 months with no change in diet. Toads in the other group (n=22) received a single oral dose of vitamins A, D3 , and E, and were fed on earthworms and crickets gut-loaded with produce and a finely-ground alfalfa-based pellet, dusted with the same vitamin/mineral supplement. All affected animals developed severe BSD equally and died during, or were euthanized at the end of, the treatment regimen, with no clinical improvement. Animals supplemented with Aquasol-A had significantly higher liver vitamin A concentrations compared with the other treatment group, whereas serum retinol concentrations showed no significant difference. Vitamin A supplementation does not appear a successful treatment once BSD symptoms have developed.

  10. Microfluorometric analyses of glycogen in freshly dissected, single skeletal muscle fibres of the cane toad using a mechanically skinned fibre preparation. (United States)

    Nguyen, L T; Stephenson, D G; Stephenson, G M


    The main objective of this study was to analyse glycogen in single muscle fibres, using a recently developed microfluorometric method which detects subpicomol amounts of NADPH, glucose and glycogen (as glucosyl units) (detection limit 0.16-0.17 pmol in a 25 nl sample) without fluorochrome amplification. The fibres were freshly dissected from the twitch region of the iliofibularis muscle of the cane toad (Bufo marinus), and were mechanically skinned under paraffin oil to gain access to the intracellular compartments. The results show that (1) glycogen concentrations in toad skeletal muscle fibres range between 25.8 and 369 mmol glucosyl units/litre fibre volume; (2) there is a large variation in glycogen content between individual fibres from the iliofibularis muscle of one animal; (3) there are seasonal differences in the glycogen content of toad single muscle fibres; (4) the total amount of glycogen in single muscle fibres of the toad does not decrease significantly when storing the tissue, under paraffin oil, at 20-25 degree C for up to 6 h or at 4 degree C for up to 24 h; and (5) 15-26% of fibre glycogen can be washed in an aqueous solution at pH 5-7, within 5 min, while 74-85% of fibre glycogen remains associated with the washed skinned fibre, even after 40 min exposure of the skinned fibre preparation to the aqueous environment. The retention of most glycogen in the fibre preparation after mechanical removal of the plasma membrane and extensive washing indicates that in toad skeletal muscle fibres the largest proportion of glycogen is tightly bound to intracellular structures. The results also show that the skinned muscle fibre preparation is well suited for microfluorometric glycogen determination, since low molecular weight non-glycogen contributors to the fluorescence signal can be removed from the myoplasmic space prior to the glycogen hydrolysis step.

  11. Glycogen content and excitation-contraction coupling in mechanically skinned muscle fibres of the cane toad. (United States)

    Stephenson, D G; Nguyen, L T; Stephenson, G M


    1. Mechanically skinned skeletal muscle fibres from the twitch region of the iliofibularis muscle of cane toads were used to investigate the relationship between fibre glycogen content and fibre capacity to respond to transverse tubular (T-) system depolarization. 2. A large proportion of total fibre glycogen remained in mechanically skinned muscle fibres exposed to aqueous solutions. This glycogen pool (about 80% of total fibre glycogen) was very stable when the preparation was incubated in a rigor solution (pH 7.0) but decreased gradually at a rate of 0.59+/-0.20% min-1 in a relaxing solution (200 nM [Ca2+]). The rate was considerably higher (2.66+/-0.38% min(-1)) when the preparations were exposed to 30 microM [Ca2+]. An even greater rate of glycogen loss was found after T-system depolarization-induced contractions. The Ca2+-dependent loss of fibre glycogen was caused by endogenous glycogenolytic processes. 3. Silver stained SDS gels of components eluted into relaxing solution from single skinned fibres revealed a rapid (2 min) loss of parvalbumin and at least 10 other proteins varying in molecular mass between 10 and 80 kDa but there was essentially no loss of myosin heavy and light chains and actin. Subsequent elution for a further 30 min in either relaxing or maximally Ca2+-activating solution did not result in additional, appreciable detectable loss of fibre protein. 4. Depletion of fibre glycogen was associated with loss of fibre ability to respond to T-system depolarization even though the bathing solutions contained high levels of ATP (8 mM) and creatine phosphate (10 mM). 5. The capacity of mechanically skinned fibres to respond to T-system depolarization was highly positively correlated (Pmuscle to respond to T-system depolarization is related directly or indirectly to the non-washable glycogen pool in fibres, (ii) this relationship holds for conditions where glycogen is not required as a source of energy and (iii) the mechanically skinned fibre

  12. Effect of saponin treatment on the sarcoplasmic reticulum of rat, cane toad and crustacean (yabby) skeletal muscle. (United States)

    Launikonis, B S; Stephenson, D G


    1. Mechanically skinned fibres from skeletal muscles of the rat, toad and yabby were used to investigate the effect of saponin treatment on sarcoplasmic reticulum (SR) Ca2+ loading properties. The SR was loaded submaximally under control conditions before and after treatment with saponin and SR Ca2+ was released with caffeine. 2. Treatment with 10 micrograms ml-1 saponin greatly reduced the SR Ca2+ loading ability of skinned fibres from the extensor digitorum longus muscle of the rat with a rate constant of 0.24 min-1. Saponin concentrations up to 150 micrograms ml-1 and increased exposure time up to 30 min did not further reduce the SR Ca2+ loading ability of the SR, which indicates that the inhibitory action of 10-150 micrograms ml-1 saponin is not dose dependent. The effect of saponin was also not dependent on the state of polarization of the transverse-tubular system. 3. Treatment with saponin at concentrations up to 100 micrograms ml-1 for 30 min did not affect the Ca2+ loading ability of SR in skinned skeletal muscle fibres from the twitch portion of the toad iliofibularis muscle but SR Ca2+ loading ability decreased markedly with a time constant of 0.22 min-1 in the presence of 150 micrograms ml-1 saponin. 4. The saponin dependent increase in permeability could be reversed in both rat and toad fibres by short treatment with 6 microM Ruthenium Red, a potent SR Ca2+ channel blocker, suggesting that saponin does affect the SR Ca2+ channel properties in mammalian and anuran skeletal muscle. 5. Treatment of skinned fibres of long sarcomere length (> 6 microns) from the claw muscle of the yabby (a freshwater decapod crustacean) with 10 micrograms ml-1 saponin for 30 min abolished the ability of the SR to load Ca2+, indicating that saponin affects differently the SR from skeletal muscles of mammals, anurans and crustaceans. 6. It is concluded that at relatively low concentrations, saponin causes inhibition of the skeletal SR Ca2+ loading ability in a species

  13. Relationship between depolarization-induced force responses and Ca2+ content in skeletal muscle fibres of rat and toad. (United States)

    Owen, V J; Lamb, G D; Stephenson, D G; Fryer, M W


    1. The relationship between the total Ca2+ content of a muscle fibre and the magnitude of the force response to depolarization was examined in mechanically skinned fibres from the iliofibularis muscle of the toad and the extensor digitorum longus muscle of the rat. The response to depolarization in each skinned fibre was assessed either at the endogenous level of Ca2+ content or after depleting the fibre of Ca2+ to some degree. Ca2+ content was determined by a fibre lysing technique. 2. In both muscle types, the total Ca2+ content could be reduced from the endogenous level of approximately 1.3 mmol l-1 (expressed relative to intact fibre volume) to approximately 0.25 mmol l-1 by either depolarization or caffeine application in the presence of Ca2+ chelators, showing that the great majority of the Ca2+ was stored in the sarcoplasmic reticulum (SR). Chelation of Ca2+ in the transverse tubular (T-) system, either by exposure of fibres to EGTA before skinning or by permeabilizing the T-system with saponin after skinning, reduced the lower limit of Ca2+ content to < or = 0.12 mmol l-1, indicating that 10-20% of the total fibre Ca2+ resided in the T-system. 3. In toad fibres, both the peak and the area (i.e. time integral) of the force response to depolarization were reduced by any reduction in SR Ca2+ content, with both decreasing to zero in an approximately linear manner as the SR Ca2+ content was reduced to < 15% of the endogenous level. In rat fibres, the peak size of the force response was less affected by small decreases in SR content, but both the peak and area of the response decreased to zero with greater depletion. In partially depleted toad fibres, inhibition of SR Ca2+ uptake potentiated the force response to depolarization almost 2-fold. 4. The results show that in this skinned fibre preparation: (a) T-system depolarization and caffeine application can each virtually fully deplete the SR of Ca2+, irrespective of any putative inhibitory effect of SR depletion

  14. Checklist and Simple Identification Key for Frogs and Toads from District IV of The MADA Scheme, Kedah, Malaysia. (United States)

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


    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.

  15. 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


    A mathematical model of an absorbing leaky epithelium is developed for analysis of solute coupled water transport. The non-charged driving solute diffuses into cells and is pumped from cells into the lateral intercellular space (lis). All membranes contain water channels with the solute passing...... concentration of fluid emerging from lis is then significantly larger than the concentration in lis. Thus, in absence of external driving forces the model generates isotonic transport provided a component of the solute flux emerging downstream lis is taken up by cells through the serosal membrane and pumped...... 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...

  16. Aerobic scope and cardiovascular oxygen transport is not compromised at high temperatures in the toad Rhinella marina. (United States)

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


    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.

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

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


    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.

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

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    Haley BOWCOCK, Gregory P. BROWN, Richard SHINE


    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].

  19. Effects of membrane cholesterol manipulation on excitation-contraction coupling in skeletal muscle of the toad. (United States)

    Launikonis, B S; Stephenson, D G


    1. Single mechanically skinned fibres and intact bundles of fibres from the twitch region of the iliofibularis muscle of cane toads were used to investigate the effects of membrane cholesterol manipulation on excitation-contraction (E-C) coupling. The cholesterol content of membranes was manipulated with methyl-beta-cyclodextrin (MbetaCD). 2. In mechanically skinned fibres, depletion of membrane cholesterol with MbetaCD caused a dose- and time-dependent decrease in transverse tubular (t)-system depolarization-induced force responses (TSDIFRs). TSDIFRs were completely abolished within 2 min in the presence of 10 mM MbetaCD but were not affected after 2 min in the presence of a 10 mM MbetaCD-1 mM cholesterol complex. There was a very steep dependence between the change in TSDIFRs and the MbetaCD : cholesterol ratio at 10 mM MbetaCD, indicating that the inhibitory effect of MbetaCD was due to membrane cholesterol depletion and not to a pharmacological effect of the agent. Tetanic responses in bundles of intact fibres were abolished after 3-4 h in the presence of 10 mM MbetaCD. 3. The duration of TSDIFRs increased markedly soon (< 2 min) after application of 10 mM MbetaCD and 10 mM MbetaCD-cholesterol complexes, but the Ca(2+) activation properties of the contractile apparatus were minimally affected by 10 mM MbetaCD. The Ca(2+) handling abilities of the sarcoplasmic reticulum appeared to be modified after 10 min exposure to 10 mM MbetaCD. 4. Confocal laser scanning microscopy revealed that the integrity of the t-system was not compromised by either intra- or extracellular application of 10 mM MbetaCD and that a large [Ca(2+)] gradient was maintained across the t-system. 5. Membrane cholesterol depletion caused rapid depolarization of the polarized t-system as shown independently by spontaneous TSDIFRs induced by MbetaCD and by changes in the fluorescence intensity of an anionic potentiometric dye (DiBAC(4)(3)) in the presence of MbetaCD. This rapid depolarization of

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

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    Bossuyt Franky


    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

  1. On Saozi Noodle, Toad Butter and the Chinese Character"de"%(月肃)子面、蟾酥及“的”字三议

    Institute of Scientific and Technical Information of China (English)



    "臊子面"应为"(月肃)子面",这可以从许多古籍记载中看得出来。蟾酥的制作通常是于夏秋捕捉癞蛤蟆,后去内脏,撑开晒干,用瓷匙刮癞蛤蟆的表面,促使其分泌浆液,再盛于瓷器内,干燥后就称为蟾酥。上古至清,"的"字的含义指姬妾宫人来了月经,不用口说,以红色丹砂、胭脂或其它红、绛、玄、蛾黄色颜料点在额中,意即避开房事。%"Saozi Noodle"should have been written in another way,which can be seen from many ancient books.The making of toad butter usually begins with summer and autumn when people try to catch a toad,gut it and air its dead body.Afterward the surface of toad is to be scraped with a porcelain spoon for the secreting of thick liquid to be put in a porcelain vessel.Wait until it is dried when it is called toad butter.Ever since antiquity,the meaning of"de"refers to the menstruation period of concubines and people in the imperial court.When this happens,the females don’t have to tell but put a dot made up of red cinnabar,rouge or other colors such as red,purple,black or yellow,which indicates the avoidance of having sexual intercourse.

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

    Petrovan, Silviu O.


    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

  3. How fast do amphibians disperse? Introductions, distribution and dispersal of the common frog Rana temporaria and the common toad Bufo bufo on a coastal island in Central Norway

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    Dag Dolmen


    Full Text Available The common frog (Rana temporaria and the common toad (Bufo bufo were introduced successfully to the coastal island of Frøya in Central Norway several times during 1960–2012. There is still a very high degree of conformity between sites where they were introduced and the present distribution of the two species. However, in western Frøya, a release of frogs about 1996 was followed by a quick expansion of their distribution area; in 2012 and 2013, breeding was registered close to 7 km westwards and eastwards, respectively, i.e. a population dispersal speed of approximately 0.4 km/yr. On eastern Frøya and some small islands in the archipelago, area expansions at another four frog localities have been prevented by ecological barriers like unfavourable limnetic or terrestrial habitats or salty water. Two local common toad populations on eastern Frøya do not show any expansion either. However, an apparently isolated record of the species on western Frøya in 2011 can possibly be explained by the expansion westwards of a population in northern central Frøya, where toads were introduced around 1995. This stretch is about 9.9 km, i.e. an average population dispersal speed of 0.6 km/yr.

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

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    Fernández-Palacios, O´Connor, Rocío


    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.

  5. Genetic structure and origin of a tetraploid toad species Bufo danatensis Pisanetz, 1978 (Amphibia, Bufonidae) from central Asia: Description of biochemical polymorphism and comparison of heterozygosity levels in diploid and tetraploid species

    Energy Technology Data Exchange (ETDEWEB)

    Mezhzherin, S.V.; Pisanets, E.M. [Schmalhausen Institute of Zoology, Kiev (Ukraine)


    Comparison of individual variation at 24 biochemical loci in members of the species complex of Palearctic green toads showed that the heterozygosity of the tetraploid species Bufo danatensis (H{sub obs} = 0.45) was significantly higher than that of the diploid species B. viridis, B. sp., and B. raddei (H{sub obs} = 0.009 - 0.103). Such difference can be explained only by a hybrid origin of the tetraploid species. Individual electrophoretic variability of the polyploid toad species is associated with an allelic variation that is manifested in constantly heterozygous spectra as the gene dosage effect. At the population level, this phenomenon found in Pamir toads is caused by irregular meiosis in founders of the population or by directional changes in gene regulation. Genotypic distributions in zones of contact of the diploid and tetraploid taxons demonstrate the possibility of restricted introgressive hybridization.

  6. Life history variation among geographically close populations of the toad-headed lizard (Phrynocephalus przewalskii): Exploring environmental and physiological associations (United States)

    Zeng, Zhi-Gao; Zhao, Jia-Ming; Sun, Bao-Jun


    Geographic variation in life history traits has been extensively studied along latitudinal and altitudinal clines, but life history variation among geographically close populations has received much less attention. We collected gravid female toad-headed lizards (Phrynocephalus przewalskii) and environmental data from three localities (Alxa Zuoqi, Alxa Youqi, and Shandan) across the Gobi desert in China, to examine among-population differences in reproductive strategies. The precipitation was significantly lower in Alxa Youqi than Alxa Zouqi and Shandan. Food availability was highest in Shandan, lowest in Alxa Zuoqi, with Alxa Youqi in between. Females from Shandan population were larger and produced more and larger eggs than their counterparts from the other two populations. Incubation period also differed among the populations, with the lowest incubation period in Alxa Youqi population, and the longest incubation period in Alxa Zuoqi population. Our data on the physiological mechanisms of incubation period indicated that the shortened incubation period in Alxa Youqi population was due to advanced embryogenesis completed prior to oviposition rather than higher embryonic heart rates during incubation. Therefore, our data support the hypothesis that geographically close populations can show different reproductive strategies if environmental factors vary among these populations.

  7. 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


    (V) decreased to 0.50+/-0.15 nL cm(-2) x s(-1), which is significantly different from zero. Isoproterenol decreased the osmotic concentration of the transported fluid, C(osm) approximately 2 x I(SC)(Eqv)/J(V), from 351+/-72 to 227+/-28 mOsm (Ringer's solution: 252.8 mOsm). J(V) depicted a saturating function......(V) with a [Na+] of the transported fluid of 130+/-24 mM ([Na+]Ringer's solution = 117.4 mM). Addition of bumetanide to the inside solution reduced J(V). Water was transported uphill and J(V) reversed at an excess outside osmotic concentration, deltaC(S,rev) = 28.9+/-3.9 mOsm, amiloride decreased delta......Transepithelial potential (V(T)), conductance (G(T)), and water flow (J(V)) were measured simultaneously with good time resolution (min) in isolated toad (Bufo bufo) skin epithelium with Ringer on both sides. Inside application of 5 microM isoproterenol resulted in the fast increase in G(T) from 1...

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

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    Rodrigo B. Ferreira


    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.

  9. Widespread convergence in toxin resistance by predictable molecular evolution


    Ujvari, Beata; Casewell, Nicholas R.; Sunagar, Kartik; Arbuckle, Kevin; Wüster, Wolfgang; Lo, Nathan; O’Meally, Denis; Beckmann, Christa; King, Glenn F.; Deplazes, Evelyne; Madsen, Thomas


    Convergence has strong bearing on the fundamental debate about whether evolution is stochastic and unpredictable or subject to constraints. Here we show that, in certain circumstances, evolution can be highly predictable. We demonstrate that several lineages of insects, amphibians, reptiles, and mammals have utilized the same molecular solution, via the process of convergence, to evolve resistance to toxic cardiac glycosides produced defensively by plants and bufonid toads. The repeatability ...

  10. 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


    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...

  11. Thermal effects on the dynamics and motor control of ballistic prey capture in toads: maintaining high performance at low temperature. (United States)

    Deban, Stephen M; Lappin, A Kristopher


    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.

  12. Disruption of excitation-contraction coupling and titin by endogenous Ca2+-activated proteases in toad muscle fibres. (United States)

    Verburg, Esther; Murphy, Robyn M; Stephenson, D George; Lamb, Graham D


    This study investigated the effects of elevated, physiological levels of intracellular free [Ca(2+)] on depolarization-induced force responses, and on passive and active force production by the contractile apparatus in mechanically skinned fibres of toad iliofibularis muscle. Excitation-contraction (EC) coupling was retained after skinning and force responses could be elicited by depolarization of the transverse-tubular (T-) system. Raising the cytoplasmic [Ca(2+)] to approximately 1 microm or above for 3 min caused an irreversible reduction in the depolarization-induced force response by interrupting the coupling between the voltage sensors in the T-system and the Ca(2+) release channels in the sarcoplasmic reticulum. This uncoupling showed a steep [Ca(2+)] dependency, with 50% uncoupling at approximately 1.9 microm Ca(2+). The uncoupling occurring with 2 microm Ca(2+) was largely prevented by the calpain inhibitor leupeptin (1 mm). Raising the cytoplasmic [Ca(2+)] above 1 microm also caused an irreversible decline in passive force production in stretched skinned fibres in a manner graded by [Ca(2+)], though at a much slower relative rate than loss of coupling. The progressive loss of passive force could be rapidly stopped by lowering [Ca(2+)] to 10 nm, and was almost completely inhibited by 1 mm leupeptin but not by 10 microm calpastatin. Muscle homogenates preactivated by Ca(2+) exposure also evidently contained a diffusible factor that caused damage to passive force production in a Ca(2+)-dependent manner. Western blotting showed that: (a) calpain-3 was present in the skinned fibres and was activated by the Ca(2+)exposure, and (b) the Ca(2+) exposure in stretched skinned fibres resulted in proteolysis of titin. We conclude that the disruption of EC coupling occurring at elevated levels of [Ca(2+)] is likely to be caused at least in part by Ca(2+)-activated proteases, most likely by calpain-3, though a role of calpain-1 is not excluded.

  13. Population structure, historical biogeography and demographic history of the alpine toad Scutiger ningshanensis in the Tsinling Mountains of Central China.

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    Hongzhe Meng

    Full Text Available Population genetic structure, historical biogeography and historical demography of the alpine toad Scutiger ningshanensis were studied using the combined data mtDNA cytochrome b (cyt b and the mtDNA cytochrome c oxidase subunit I (COI as the molecular markers. This species has high genetic variation. There was a significant genetic differentiation among most populations. Three lineages were detected. The phylogenetic relationship analyses and the SAMOVA (spatial analysis of molecular variance results showed significant phylogeographic structure. 82.15% genetic variation occurred among populations whereas differentiation within populations only contributed 17.85% to the total. Mantel test results showed a significant correlation between the pairwise calculated genetic distance and pairwise calculated geographical distance of the populations (regression coefficient  = 0.001286, correlation coefficient  = 0.77051, p (rrand≥robs  = 0.0185<0.05, indicating the existence of isolation-by-distance pattern of genetic divergence for cyt b + COI sequence, which suggests that the distribution of genetic variation is due to geographical separation rather than natural selection. The population expansion or contraction and genetic differentiation between populations or lineages could be explained by topography and the repetitive uplifts of the Tsinling Mountains and the climatic cycles during the late Pliocene and Pleistocene. S. ningshanensis experienced a rapid population expansion about 40,000 years before present. The current decline in population size was probably caused by anthropogenic disturbance. Current populations of S. ningshanensis are from different refugia though the location of these refugia could not be determined in our study. Topography, climatic changes and repetitive population expansion/contraction together led to the high level of genetic variation in S. ningshanensis. A total of three management units (MUs was determined

  14. Expression pattern of glycoconjugates in the Bidderian and ovarian follicles of the Brazilian toad Bufo ictericus analyzed by lectin histochemistry

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    C. F. Farias

    Full Text Available The Bidder's organ and ovary of the Brazilian toad Bufo ictericus were studied by light microscopy, using hematoxylin-eosin (HE and periodic acid Schiff (PAS staining. The expression and distribution of carbohydrate moieties was analyzed by lectin histochemistry, using 8 lectins with different carbohydrate specificities: Ulex europaeus (UEA I, Lens culinaris (LCA, Erythrina cristagalli (ECA, Arachis hypogaea (PNA, Ricinus communis (RCA I, Aleuria aurantia (AAA, Triticum vulgaris (WGA, and Glycine maximum (SBA. The results showed that the Bidderian zona pellucida presented alpha-mannose, alpha-L-fucose, beta-D-galactose, N-acetyl-D-glucosamine, and alpha/beta-N-acetyl-galactosamine residues. The Bidderian follicular cells showed the presence of beta-D-galactose and N-acetyl-D-glucosamine. In the extracellular matrix, alpha-mannose and alpha/beta-N-acetyl-galactosamine residues were detected. The ovarian zona pellucida showed alpha-L-fucose, N-acetyl-D-glucosamine, alpha/beta-N-acetyl-galactosamine residues, and alpha-mannose and N-acetyl-D-glucosamine residues were detected in the follicular cells. Thus, the zona pellucida in both organs contains N-acetyl-D-glucosamine, and alpha/beta-N-acetyl-galactosamine residues. alpha-L-fucose residues were detected in the zona pellucida of both organs, using different lectins. Considering that beta-D-galactose residue was absent from ovary but present in the Bidder's organ, this sugar residue may play an important role in follicle development, blocking the Bidderian follicles and preventing further development of the Bidder's organ into a functional ovary.

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

    Crespi, Erica J; Denver, Robert J


    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.

  16. A vertebrate reproductive system involving three ploidy levels: hybrid origin of triploids in a contact zone of diploid and tetraploid palearctic green toads (Bufo viridis subgroup). (United States)

    Stöck, Matthias; Ustinova, Jana; Lamatsch, Dunja K; Schartl, Manfred; Perrin, Nicolas; Moritz, Craig


    The rise and consequences of polyploidy in vertebrates, whose origin was associated with genome duplications, may be best studied in natural diploid and polyploid populations. In a diploid/tetraploid (2n/4n) geographic contact zone of Palearctic green toads in northern Kyrgyzstan, we examine 4ns and triploids (3n) of unknown genetic composition and origins. Using mitochondrial and nuclear sequence, and nuclear microsatellite markers in 84 individuals, we show that 4n (Bufo pewzowi) are allopolyploids, with a geographically proximate 2n species (B. turanensis) being their maternal ancestor and their paternal ancestor as yet unidentified. Local 3n forms arise through hybridization. Adult 3n mature males (B. turanensis mtDNA) have 2n mothers and 4n fathers, but seem distinguishable by nuclear profiles from partly aneuploid 3n tadpoles (with B. pewzowi mtDNA). These observations suggest multiple pathways to the formation of triploids in the contact zone, involving both reciprocal origins. To explain the phenomena in the system, we favor a hypothesis where 3n males (with B. turanensis mtDNA) backcross with 4n and 2n females. Together with previous studies of a separately evolved, sexually reproducing 3n lineage, these observations reveal complex reproductive interactions among toads of different ploidy levels and multiple pathways to the evolution of polyploid lineages.

  17. Vitamin A values of wild-caught Cuban tree frogs (Osteopilus septentrionalis) and marine toads (Rhinella marina) in whole body, liver, and serum. (United States)

    Sullivan, Kathleen E; Fleming, Greg; Terrell, Scott; Smith, Dustin; Ridgley, Frank; Valdes, Eduardo V


    Recent issues surrounding captive amphibians are often nutritionally related problems, such as hypovitaminosis A. Although supplementation of frogs with vitamin A is a topic of investigation, the underlying issue is understanding vitamin A metabolism in amphibian species. To develop a range of "normal" vitamin A concentrations for captive amphibians, baseline vitamin A concentrations must be established in wild amphibian species. In this study, two species, Cuban tree frogs (Osteopilus septentrionalis; n = 59) and marine toads (Rhinella marina; n = 20) were collected from the wild as part of an invasive species control program at Zoo Miami, Miami, Florida. Serum, liver, and whole body samples were analyzed for vitamin A content. The Cuban tree frogs showed higher concentrations on average of vitamin A in serum (82.8 ppb), liver (248.3 IU/g), and whole body (5474.7 IU/kg) samples compared with marine toads (60.1 ppb; 105.3 IU/g; 940.7 IU/kg, respectively), but differences were not significant (P = 0.22). What can be considered "normal" values of vitamin A concentrations across different amphibian species requires further investigation. Although all amphibians collected in this study appeared healthy, a larger sample size of animals, with known health histories and diets, may provide stronger evidence of normal expectations.

  18. Disruption of excitation–contraction coupling and titin by endogenous Ca2+-activated proteases in toad muscle fibres (United States)

    Verburg, Esther; Murphy, Robyn M; Stephenson, D George; Lamb, Graham D


    This study investigated the effects of elevated, physiological levels of intracellular free [Ca2+] on depolarization-induced force responses, and on passive and active force production by the contractile apparatus in mechanically skinned fibres of toad iliofibularis muscle. Excitation–contraction (EC) coupling was retained after skinning and force responses could be elicited by depolarization of the transverse-tubular (T-) system. Raising the cytoplasmic [Ca2+] to ∼1 μm or above for 3 min caused an irreversible reduction in the depolarization-induced force response by interrupting the coupling between the voltage sensors in the T-system and the Ca2+ release channels in the sarcoplasmic reticulum. This uncoupling showed a steep [Ca2+] dependency, with 50% uncoupling at ∼1.9 μm Ca2+. The uncoupling occurring with 2 μm Ca2+ was largely prevented by the calpain inhibitor leupeptin (1 mm). Raising the cytoplasmic [Ca2+] above 1 μm also caused an irreversible decline in passive force production in stretched skinned fibres in a manner graded by [Ca2+], though at a much slower relative rate than loss of coupling. The progressive loss of passive force could be rapidly stopped by lowering [Ca2+] to 10 nm, and was almost completely inhibited by 1 mm leupeptin but not by 10 μm calpastatin. Muscle homogenates preactivated by Ca2+ exposure also evidently contained a diffusible factor that caused damage to passive force production in a Ca2+-dependent manner. Western blotting showed that: (a) calpain-3 was present in the skinned fibres and was activated by the Ca2+exposure, and (b) the Ca2+ exposure in stretched skinned fibres resulted in proteolysis of titin. We conclude that the disruption of EC coupling occurring at elevated levels of [Ca2+] is likely to be caused at least in part by Ca2+-activated proteases, most likely by calpain-3, though a role of calpain-1 is not excluded. PMID:15746171

  19. Regulation of cyclic GMP metabolism in toad photoreceptors. Definition of the metabolic events subserving photoexcited and attenuated states. (United States)

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


    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)

  20. Changes in serum and urinary corticosterone and testosterone during short-term capture and handling in the cane toad (Rhinella marina). (United States)

    Narayan, Edward J; Cockrem, John; Hero, Jean-Marc


    Non-invasive endocrine monitoring with minimally invasive biological samples, such as urine, is being used widely for conservation biology research on amphibians. Currently, it is unknown how closely urinary measurements correspond with the traditional serum hormone measurements. We compared urinary and serum concentrations of corticosterone (CORT) and testosterone (T) in adult male cane toads (Rhinella marina) using a standard capture and handling (short-term stressor) protocol. Free-living male cane toads were captured and sampled for baseline urine (0h) with a second urine sample taken at 0.5h and hourly between 1 and 8h. A single blood sample was collected from each toad after the final urine sampling and capture handling. The mean serum CORT concentration increased between 0 and 0.5h, reaching the highest level between 6 and 8h. The mean urinary CORT concentration increased with a lag-time of 1h and continued to increase up to 8h. The mean level of serum T decreased between 0 and 7h and increased between 7 and 8h. Mean urinary T concentration decreased with a lag-time of 0.5h. Urinary T levels did not change between 4 and 8h. Mean serum T levels reached 50% of the original 0h value at 1h while mean serum CORT levels reached 200% of the original 0h value within 0.5h. Mean urinary T levels reached 50% of the original 0h value within 3h while mean urinary CORT levels reached 200% of the original 0h value within 3h. The inter-individual variation in baseline serum and urinary CORT and T levels were highly comparable, suggesting that baseline urine sample provides a reliable indicator of the physiological status of the animal. Overall, the results have demonstrated that urine sampling and standard capture handling protocol provide reliable measures of baseline corticosterone and testosterone, as well as short-term stress hormone responses in amphibians.

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

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    Mu Yang


    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.

  2. Effects of meal size, meal type, body temperature, and body size on the specific dynamic action of the marine toad, Bufo marinus. (United States)

    Secor, Stephen M; Faulkner, Angela C


    Specific dynamic action (SDA), the accumulated energy expended on all physiological processes associated with meal digestion, is strongly influenced by features of both the meal and the organism. We assessed the effects of meal size, meal type, body temperature, and body size on the postprandial metabolic response and calculated SDA of the marine toad, Bufo marinus. Peak postprandial rates of O(2) consumption (.V(O2)) and CO(2) production (.V(CO2)) and SDA increased with meal size (5%-20% of body mass). Postprandial metabolism was impacted by meal type; the digestion of hard-bodied superworms (Zophobas larva) and crickets was more costly than the digestion of soft-bodied earthworms and juvenile rats. An increase in body temperature (from 20 degrees to 35 degrees C) altered the postprandial metabolic profile, decreasing its duration and increasing its magnitude, but did not effect SDA, with the cost of meal digestion remaining constant across body temperatures. Allometric mass exponents were 0.69 for standard metabolic rate, 0.85 for peak postprandial .V(O2), and 1.02 for SDA; therefore, the factorial scope of peak postprandial .V(O2) increased with body mass. The mass of nutritive organs (stomach, liver, intestines, and kidneys) accounted for 38% and 20% of the variation in peak postprandial .V(O2) and SDA, respectively. Toads forced to exercise experienced 25-fold increases in .V(O2) much greater than the 5.5-fold increase experience during digestion. Controlling for meal size, meal type, and body temperature, the specific dynamic responses of B. marinus are similar to those of the congeneric Bufo alvarius, Bufo boreas, Bufo terrestris, and Bufo woodhouseii.

  3. The genetics of amphibian decline: population substructure and molecular differentiation in the Yosemite toad, Bufo canorus (Anura, Bufonidae) based on single-strand conformation polymorphism analysis (SSCP) and mitochondrial DNA sequence data (United States)

    Shaffer, H. Bradley; Fellers, Gary M.; Magee, Allison; Voss, S. Randal


    We present a comprehensive survey of genetic variation across the range of the narrowly distributed endemic Yosemite toad Bufo canorus, a declining amphibian restricted to the Sierra Nevada of California. Based on 322 bp of mitochondrial cytochrome b sequence data, we found limited support for the monophyly of B. canorus and its closely related congener B. exsul to the exclusion of the widespread western toad B. boreas. However, B. exsul was always phylogenetically nested within B. canorus, suggesting that the latter may not be monophyletic. SSCP (single-strand conformation polymorphism) analysis of 372 individual B. canorus from 28 localities in Yosemite and Kings Canyon National Parks revealed no shared haplotypes among these two regions and lead us to interpret these two parks as distinct management units for B. canorus. Within Yosemite, we found significant genetic substructure both at the level of major drainages and among breeding ponds. Kings Canyon samples show a different pattern, with substantial variation among breeding sites, but no substructure among drainages. Across the range of B. canorus as well as among Yosemite ponds, we found an isolation-by-distance pattern suggestive of a stepping stone model of migration. However, in Kings Canyon we found no hint of such a pattern, suggesting that movement patterns of toads may be quite different in these nearby parklands. Our data imply that management for B. canorus should focus at the individual pond level, and effective management may necessitate reintroductions if local extirpations occur. A brief review of other pond-breeding anurans suggests that highly structured populations are often the case, and thus that our results for B. canorus may be general for other species of frogs and toads.

  4. Effect of drying methods on the free and conjugated bufadienolide content in toad venom determined by ultra-performance liquid chromatography-triple quadrupole mass spectrometry coupled with a pattern recognition approach. (United States)

    Zhou, Jing; Gong, Yan; Ma, Hongyue; Wang, Honglan; Qian, Dawei; Wen, Hongmei; Liu, Rui; Duan, Jinao; Wu, Qinan


    Drying is a useful technique for extending the shelf-life of biological products and enabling long-term storage; however, improper drying can reduce the chemical quality of the products. In this study, we used ultra-performance liquid chromatography-triple quadrupole/mass spectrometry (LC-MS/MS) and multivariate statistical analysis to investigate the effects of four drying methods (V: vacuum-drying at 60°C, F: freeze-drying, H: air-drying at 60°C and R: air-drying at room temperature) on the levels of 36 bufadienolides in toad venom. Vacuum-drying at 60°C produced the highest quality dried toad venom in terms of total bufadienolide content, whereas traditional air-drying at room temperature (RT) to dehydrate the toad venom led to a dramatic loss in free and conjugated bufadienolides, reaching up to 60% and 70%, respectively. Assaying for free bufadienolides ranked the drying methods as V≈F>H>R, whereas assaying for conjugated bufadienolides slightly changed the order to V>F≈H>R. Furthermore, we identified 21 bufadienolides as biomarkers responsible for the decline in the quality of dried toad venom, whose loss varied from 1.5-fold to 100-fold. Of these biomarkers, group I bufadienolides that contain 16-OAc (e.g., cinobufagin and its hydroxyl or arginine ester derivatives) were characteristic components and were reduced to trace levels (loss of more than 10-fold) following traditional air-drying at RT. This might be attributed to the fact that most enzyme-sensitive bufadienolides were biotransformed or degraded at room temperature but were retained using other drying methods.

  5. 经腹壁静脉给药建立蟾蜍高钾血症动物模型的研究%Research on injection through the abdominal vein to establish hyperkalemia model of toad

    Institute of Scientific and Technical Information of China (English)

    霍健; 苏兴利; 王爽


    目的:建立在体蟾蜍心脏高钾血症(hyperkalemia)动物模型,现察血钾升高时蟾蜍Ⅱ导联心电图(electrocardiographⅡ,ECGⅡ)的影响.方法:经腹壁静脉注射0.2%氯化钾(KCl)使蟾蜍血钾浓度升高,并记录ECGⅡ.结果:注射0.2%KCI后ECG立即显示心率减慢,P-R间期延长,QRS波群增宽变低,T波明显高尖.结论:经腹壁静脉给药建立蟾蜍急性高钾血症所致ECG的改变与哺乳动物高钾血症有相似之处;与其他高钾血症动物模型比较,本方法具有操作简便快速、实验结果稳定、成本低廉的优势.%Objective To construct the toad cardiac muscle model of hyperkalemia and observe the effect of hyperkalemia on electrocardiogram Ⅱ ( ECG Ⅱ).Methods 0.2 % potassium chloride was injected via the abdominal vein to establish the hyperkalemia model of toad muscle cell.ECG Ⅱ was synchronously recorded.Results After 0.2 % KCI was injected, heart rate was slowed down, P-R interval was extended, QRS was broad and slowly and T peak became higher.Conclusion The toad model of hyperkalemia could be established by injection of 0.2% KCI via the abdominal vein, and the changes of ECG in toad are similar to mammal.Compared with other methods of animal models, the method has advantages of simple and rapid operations, stable results and low cost.

  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


    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. Temperature seems to be an important factor when assessing effects of a glyphosate-based herbicide on egg and tadpole growth of Common toads (Bufo bufo; Amphibia L.

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    Fabian Baier


    Full Text Available Glyphosate-based herbicide formulations are broadly used in agriculture, silviculture, horticulture as well as in private gardens all over the world, thus posing the risk of potential contamination of nearby aquatic bodies inhabited by amphibians. Concurrently, climate change can be expected to alter the temperature of amphibian breeding sites. However, while either glyphosate-based herbicides or temperature have been shown to separately affect the development of amphibians, very little is known on possible interactive effects. We studied the impact of herbicide concentrations and temperature on growth and development of eggs and tadpoles of the Common toad (Bufo bufo L.. We hypothesized that (i eggs would be better protected against herbicides than tadpoles because of their jelly coating, (ii that higher temperatures would reduce potential herbicide effects because of an accelerated growth and a lower sensitivity of larger specimens. We conducted one experiment starting with eggs (Gosner stage, GS 9 and another experiment starting with tadpoles (GS 21-24 using a full factorial design with 5 concentrations of the herbicide formulation Roundup® LB Plus (0 mg acid equivalent L-1, 0.5 mg a.e. L-1, 1.0 mg a.e. L-1 or 1.5 mg a.e. L-1 and a pulse treatment with 3-4 times addition of 0.5 a.e. mg L-1 over the course of several weeks and two temperature levels (15°C and 20°C. Contrary to our expectation, our results showed that toad eggs are more sensitive to herbicides than tadpoles leading to an averaged 31% increase in total length, tail length and body length compared to the herbicide-free control. Tadpole morphology, development or mortality was not influenced by herbicides. Higher temperature accelerated growth of both eggs and tadpoles. This is among the first study showing interactive effects between herbicides and temperature especially for egg development resulting in more pronounced herbicide effects at lower temperatures than at higher

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

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    Schneider Horacio


    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

  9. Different morphologic formation patterns of dark patches in the black-spotted frog (Pelophylax nigromaculata) and the Asiatic toad (Bufo gargarizans). (United States)

    Guangming, Gan; Tao, Zhao; Chao, Li; Moyan, Zhao


    The black-spotted frog (Pelophylax nigromaculata) and Asiatic toad (Bufo gargarizans), two relatively distantly related species, live in different habitats with different adaptive dark patches. To explain the formation of dark patches, the distribution patterns of melanin granules were examined with light microscopy and transmission electron microscopy. Melanin granules were produced and gathered into the "cap" structures on top of the nuclei in most epidermal cells. The "cap" structures may play a role in forming the dorsal dark patches coupled with three-layer melanophores, which can give rise to three layers of interconnected melanin networks in the dorsal dermis in P. nigromaculata. Epidermal melanocytes are rare and do not have a definitive role in forming dorsal dark patches in either P. nigromaculata or B. gargarizans. In B. gargarizans, the dermal melanophores only give rise to a single-layered melanin network, which hardly results in dark patches in the dorsal skin. However, the dermal melanophores migrate twice and form into pseudostratified networks, leading to dark patch formation in the ventral skin in B. gargarizans. The melanin granules precisely coregulate dark patches in the dermis and/or epidermis in P. nigromaculata and B. gargarizans. The dark patch formation depends on melanin granules in the epidermis or/and dermis in P. nigromaculata and B. gargarizans.

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

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    Sanuy, D.


    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.

  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)



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

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    Sara Quagliata


    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.

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

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


    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.

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

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


    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.

  15. Small frogs get their worms first: the role of nonodonate arthropods in the recruitment of Haematoloechus coloradensis and Haematoloechus complexus in newly metamorphosed northern leopard frogs, Rana pipiens, and woodhouse's toads, Bufo woodhousii. (United States)

    Bolek, Matthew G; Janovy, John


    Studies on the life cycles and epizootiology of North American frog lung flukes indicate that most species utilize odonates as second intermediate hosts; adult frogs become infected by ingesting odonate intermediate hosts. Newly metamorphosed frogs are rarely infected with these parasites, predominantly because they are gape-limited predators that cannot feed on large intermediate hosts such as dragonflies. We examined the role of the frog diet and potential intermediate hosts in the recruitment of the frog lung fluke, Haematoloechus coloradensis, to metamorphosed northern leopard frogs (Rana pipiens), Woodhouse's toads (Bufo woodhousii), and bullfrogs (Rana catesbeiana) from western Nebraska. Because of the uncertain validity of H. coloradensis as a distinct species from Haematoloechus complexus, morphological characters of both species were reevaluated and the life cycles of both species were completed in the laboratory. The morphological data on H. coloradensis and H. coimplexus indicate that they differ in their oral sucker to pharynx ratio, uterine loop distribution, and placement of vitelline follicles. However, in terms of their life cycles, both species are quite similar in their use of physid snails as first intermediate hosts, a wide range of nonodonate and odonate arthropods as second intermediate hosts, and leopard frogs and toads as definitive hosts. These results indicate that H. coloradensis and H. complexus are generalists at the second intermediate host level and might be able to infect newly metamorphosed leopard frogs and toads by using small nonodonate arthropods more commonly than other frog lung fluke species. Comparisons of population structure of adult flukes in newly metamorphosed leopard frogs indicate that the generalist nature of H. coloradensis metacercariae enables it to colonize young of the year leopard frogs more commonly than other Haematoloechus spp. that only use odonates as second intermediate hosts. In this respect, the

  16. 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.;


    studied in toads (Bufo bufo) immediately before, and after 2,7, and 14 days exposure to distilled water. General epidermal structure was not affected. However, the numbers of MRCs per mm2 (DMRC) increased throughout the experiment as revealed by staining of epidermal sheets with AgNO3 (Ag) or methylene...... blue (MB). Part of the increased DMRC was accounted for by an increase in MRC subpopulation(s) that stained neither with Ag nor MB. The cell birth rate (Kb) decreased and cell loss by moulting (Kd) increased without any significant change in epidermal cell pool size, indicating a reduced apoptotic rate...

  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


    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, 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, como acetato de Pb. Los anticuerpos naturales

  18. Glycopattern analysis and structure of the egg extra-cellular matrix in the Apennine yellow-bellied toad, Bombina pachypus (Anura: Bombinatoridae

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    Giovanni Scillitani


    Full Text Available We studied the glycopatterns and ultrastructure of the extra-cellular matrix (ECM of the egg of theApennine yellow-bellied toad Bombina pachypus, by light and electron microscopy in order to determine structure,chemical composition and function. Histochemical techniques in light microscopy included PAS and AlcianBlue pH 2.5 and 1.0, performed also after b-elimination. Lectin-binding was tested with nine lectins (AAA,ConA, DBA, HPA, LTA, PNA, SBA, UEA-I, WGA. An inner fertilization envelope (FE and five jelly layers(J1–J5 were observed, differing in histochemical staining, lectin binding and ultrastructure. Most glycans wereO-linked, with many glucosamylated and fucosylated residues. The fertilization envelope presented a perivitellinespace and a fertilization layer, with mostly neutral glycans. The jelly layers consisted of fibers and granules,whose number and orientation differed between layers. Fibers were densely packed in J1 and J4 layers,whereas a looser arrangement was observed in the other layers. Jelly-layer glycans were mostly acidic and particularlyabundant in the J1 and J4 layers. In the J1, J2 and J5 layers, neutral, N-linked glycans were also observed.Mannosylated and/or glucosylated as well as galactosyl/galactosaminylated residues were more abundant in theouter layers. Many microorganisms were observed in the J5 layer. We believe that, apart from their functions inthe fertilization process, acidic and fucosylated glycans could act as a barrier against pathogen penetration.

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

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    Perrin Nicolas


    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

  20. Synergy between glyphosate- and cypermethrin-based pesticides during acute exposures in tadpoles of the common South American toad Rhinella arenarum. (United States)

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


    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.

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

    Janssens, P A; Grigg, J A


    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.

  2. Foleyellides rhinellae sp. nov. (Nematoda, Onchocercidae) a new filaria parasitizing Rhinella marina (Anura, Bufonidae) in Mexico. (United States)

    García-Prieto, Luis; Ruiz-Torres, Nallely; Osorio-Sarabia, David; Merlo-Serna, Aldo


    A new nematode species, Foleyellides rhinellae sp. nov. (Onchocercidae), is described from specimens found in the body cavity of the cane toad, Rhinella marina (Linnaeus) (Anura, Bufonidae), in the Laguna de Coyuca, Guerrero, in the Pacific slope of Mexico. The new species differs from the other nine species of Foleyellides by infecting bufonid anurans and by the number and arrangement of caudal papillae. Other distinguishing feature of the new species is the size of the left spicule (0.16-0.23 long), the smallest recorded among the species included in the genus. Foleyellides rhinellae sp. nov. is the second known species of the genus recorded from amphibians of Mexico.

  3. 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. (United States)

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


    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 < 0.001). Hemoglobin and mean corpuscular hemoglobin levels, as well as the condition factor, are found to be lower at industrial sites compared with the reference sites. Our results suggest that the R. marina can be considered a good biomonitor of the δ-ALAD activity inhibition and hematological alterations at low lead concentrations.

  4. Non-target effects of a glyphosate-based herbicide on Common toad larvae (Bufo bufo, Amphibia and associated algae are altered by temperature

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    Fabian Baier


    Full Text Available Background Glyphosate-based herbicides are the most widely used pesticides in agriculture, horticulture, municipalities and private gardens that can potentially contaminate nearby water bodies inhabited by amphibians and algae. Moreover, the development and diversity of these aquatic organisms could also be affected by human-induced climate change that might lead to more periods with extreme temperatures. However, to what extent non-target effects of these herbicides on amphibians or algae are altered by varying temperature is not well known. Methods We studied effects of five concentrations of the glyphosate-based herbicide formulation Roundup PowerFlex (0, 1.5, 3, 4 mg acid equivalent glyphosate L−1 as a one time addition and a pulse treatment of totally 4 mg a.e. glyphosate L−1 on larval development of Common toads (Bufo bufo, L.; Amphibia: Anura and associated algae communities under two temperature regimes (15 vs. 20 °C. Results Herbicide contamination reduced tail growth (−8%, induced the occurrence of tail deformations (i.e. lacerated or crooked tails and reduced algae diversity (−6%. Higher water temperature increased tadpole growth (tail and body length (tl/bl +66%, length-to-width ratio +4% and decreased algae diversity (−21%. No clear relation between herbicide concentrations and tadpole growth or algae density or diversity was observed. Interactive effects of herbicides and temperature affected growth parameters, tail deformation and tadpole mortality indicating that the herbicide effects are temperature-dependent. Remarkably, herbicide-temperature interactions resulted in deformed tails in 34% of all herbicide treated tadpoles at 15 °C whereas no tail deformations were observed for the herbicide-free control at 15 °C or any tadpole at 20 °C; herbicide-induced mortality was higher at 15 °C but lower at 20 °C. Discussion These herbicide- and temperature-induced changes may have decided effects on ecological

  5. 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


    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。


    Institute of Scientific and Technical Information of China (English)

    费梁; 叶昌媛; 江建平


    对世界蟾蜍科动物的分类现状做了概述,并对我国原定名为鳞皮游蟾Nectophryne scalptus Liu and Hu(1973)及叶昌媛等(1978)将其改为鳞皮厚蹼蟾Pelophryne scalptus(Frost,1985订正种名为scalpta)的海南标本做了进一步研究,与现有蟾蜍科各属、特别是与东南亚地区的几个特有属的特征做了对比研究.结果表明:原定名为鳞皮游蟾Nectophryne scalptus的海南标本应代表一个新属即小蟾属Parapelophryne gen.nov,因此原定名为鳞皮游蟾(或鳞皮厚蹼蟾)的标本为新属的成员,即种名应改为鳞皮小蟾Parapelophryne scalpta(Liu and Hu).

  7. The plasticizer bisphenol A affects somatic and sexual development, but differently in pipid, hylid and bufonid anurans. (United States)

    Tamschick, Stephanie; Rozenblut-Kościsty, Beata; Ogielska, Maria; Kekenj, David; Gajewski, Franz; Krüger, Angela; Kloas, Werner; Stöck, Matthias


    Due to their terrestrial habitats and aquatic reproduction, many amphibians are both very vulnerable and highly suitable bioindicators. The plasticizer bisphenol A (BPA) is one of the most produced chemical substances worldwide, and knowledge on its impacts on humans and animals is mounting. BPA is used for the industrial production of polycarbonate plastics and epoxy resins and found in a multitude of consumer products. Studies on BPA have involved mammals, fish and the fully aquatic anuran model Xenopus laevis. However, our knowledge about the sexual development of non-model, often semi-terrestrial anuran amphibians remains poor. Using a recently developed experimental design, we simultaneously applied BPA to two non-model species (Hyla arborea, Hylidae; Bufo viridis, Bufonidae) and the model X. laevis (Pipidae), compared their genetic and phenotypic sex for detection of sex reversals, and studied sexual development, focusing on anatomical and histological features of gonads. We compared three concentrations of BPA (0.023, 2.28 and 228 μg/L) to control groups in a high-standard flow-through-system, and tested whether conclusions, drawn from the model species, can be extrapolated to non-model anurans. In contrast to previous studies on fish and Xenopus, often involving dosages much higher than most environmental pollution data, we show that BPA causes neither the development of mixed sex nor of sex-reversed individuals (few, seemingly BPA-independent sex reversals) in all focal species. However, environmentally relevant concentrations, as low as 0.023 μg/L, were sufficient to provoke species-specific anatomically and histologically detectable impairments of gonads, and affected morphological traits of metamorphs. As the intensity of these effects differed between the three species, our data imply that BPA diversely affects amphibians with different evolutionary history, sex determination systems and larval ecologies. These results highlight the role of amphibians as a sensitive group that is responsive to environmental pollution.

  8. 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


    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


    Institute of Scientific and Technical Information of China (English)

    李仁德; 李云鸿; 陈强


    应用高效液相色谱法(HPLC)-UV检测了不同季节荒漠沙蜥(Phrynocephalus przewalskii)松果体内褪黑激素的含量.结果显示,其高峰值发生在春季,为1 017±209 pg/pineal.低峰值出现在冬季(实验室内冬眠,2~4℃),为355±68.5 pg/pineal,秋季的含量(735±133.7 pg/pineal)高于夏季的含量(597±94.9 pg/pineal).表明荒漠沙蜥松果体褪黑激素含量呈现明显的年周期节律并与光周期和生殖周期的年节律基本相符.%Seasonal variation in the pineal melatonin content of toad-headed lizards was determined by HPLC. The highest melatonin content (1 017±209 pg/pineal) occurred in spring and the lowest (335±68.5 pg/pineal) in winter. Melatonin levels in autumn (735±133 pg/pineal) were higher than in summer (597±94.9 pg/pineal). We conclude that pineal melatonin content has remarkable seasonal variation that coincides with photoperiod and reproductive rhythms.

  10. 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


    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.

  11. Characteristics of the relative refractory period of compound active potential of sciatic stem in toads%蟾蜍坐骨神经复合动作电位相对不应期的特征

    Institute of Scientific and Technical Information of China (English)

    郭华; 曲瑞瑶; 童学红


    背景:神经纤维疾病的患者经常被推荐做复合动作电位相对不应期的测定,但其在不同刺激条件下的特性始终并未完全证实.目的:通过蟾蜍坐骨神经复合动作电位的实验,更加全面地阐述复合动作电位相对不应期爆发动作电位的特点.设计:随机非对照的实验研究.地点和对象:由首都医科大学实验动物中心提供的6只蟾蜍,在同一生理学实验室被处死来做实验.干预:以不同的刺激强度和组合方式刺激神经.主要观察指标:用NSA-Ⅲ医学信号处理系统记录相对不应期发生动作电位的幅度.结果:在相对不应期的同一时刻,较强的刺激会引起较大幅度的复合动作电位,并且在同样的刺激强度下,不会产生太大变化.结论:在同一时期对相对不应期的刺激可引起不同阈值的神经纤维不同概率性的兴奋,但它们可以固定的概率性叠加,以形成稳定的动作电位.此外,神经干中A类神经纤维的最短绝对不应期可以通过足够强的刺激来测定.%BACKGROUND: The measure of "relative refractory period of compound action potential" is commonly recommended for patients with nervous fiber diseases. But its characteristics with different intensities of stimulus have not been completely proved.OBJECTIVE: To illustrate the characteristics of action potential occurring in "relative refractory period of compound action potential" from the experiment of compound action potential of sciatic stem in toads.DESIGN: A randomly uncontrolled trial study.SETTING and MATERIALS: Six toads were provided by the Experimental Animal Center of Capital University of Medical Sciences and were killed for experiment at the same physiology laboratory.INTERVENTIONS: The sciatic stems were stimulated with different intensities and combinations.MAIN OUTCOME MEASURES: The amplitudes of action potential occurring in relative refractory period were recorded by NSA-Ⅲ medical signal processing system

  12. 蟾蜍Caveolin-1的生物信息学分析及其在肌肉组织中的表达%Bioinformatics analysis of Caveolin-1 in toad and its expression in muscle tissues

    Institute of Scientific and Technical Information of China (English)

    张叶军; 解文放; 李洪艳; 崔玉影; 邹伟


    The Caveolin-1 protein sequence of Xenopus laevis in GenBank was obtained and its struc-ture and function were predicted through various bioinformatics analysis softwares . The results showed that Caveolin-1 of toad and mammals have similar structures and functions .Total protein from muscle tissues of Bufo gargarizans was extracted and the Caveolin-1 had been detected through Western Blot by mouse anti-human Caveolin-1 polyclonal antibody .It was suggested that Caveolin-1 is highly conserved in the long biological evolution process ,and maintains its function as a signal transduction center .%在GenBank中获得非洲爪蟾Caveolin-1蛋白序列,通过多种生物信息学分析软件对其进行分析,预测其结构和功能。以成年中华大蟾蜍为实验材料,提取蟾蜍不同肌肉组织的总蛋白,通过Western Blot技术检测Caveolin-1在肌肉组织中的表达。结果表明:蟾蜍的Caveolin-1与哺乳动物Caveolin-1有着相似的结构和功能;利用本实验室已有的抗人Caveolin-1多克隆抗体在中华大蟾蜍的不同肌肉组织中检测到了Caveolin-1的表达,从另一个角度验证了Caveolin-1的保守性。

  13. 蟾酥固体脂质纳米粒包封率测定%Determination of entrapment efficiencies of cinobufagin and resibufogenin in the toad venom solid lipid nanoparticles

    Institute of Scientific and Technical Information of China (English)

    张素娟; 张永太; 申利娜; 王志; 冯年平


    Objective:To determine the entrapment efficiencies (EE) of cinobufagin (CBG) and resibufogenin (RBG) in the toad venom solid lipid nanoparticles (SLN) by evaluation of the effects of ultrafiltration membrane type,adsorbability and penetration for nanoparticles.Methods:Different types of ultrafiltration membranes were selected to investigate the appropriate molecular weight cut-off (MWCO),and then the membrane adsorbability for various concentrations of the SLN suspensions.The penetrability of SLN through membrane was evaluated as well.Results:The EEs of CBG (92.62 ±1.22)% and RBG (91.07 ±0.46)% were the highest as determined by the ultrafiltration membrane with MWCO of 10 kDa.The selected ultrafiltration membrane showed little adsorbability for CBG and RBG,and could effectively intercept SLN.With the optimized method,the determined EEs of CBG and RBG were (91.94 ± 0.72) % and (92.38 ± 0.65) %,respectively.Conclusion:MWCO of the ultrafiltration membrane has great influence on the determination of EE of SLN,and the selected ultrafiltration membrane with MWCO of 10 kDa can be applied in determination of EEs of CBG and RBG in the SLN.%目的:考察超滤膜型号、吸附性、透过能力对蟾酥固体脂质纳米粒(SLN)包封率(EE)测定的影响,确定包封率测定方法.方法:分别选择不同截留相对分子质量超滤膜进行考察,优选适宜型号超滤膜,评价其对不同浓度SLN混悬液中药物的吸附性,并考察其对SLN的透过能力,综合评价超滤膜在蟾酥固体脂质纳米粒的包封率测定中的适应性.结果:截留相对分子质量为10 kDa的超滤膜测定所得药物包封率较高,华蟾酥毒基与脂蟾毒配基包封率分别为(92.62±1.22)%和(91.07±0.46)%;超滤膜对所测指标性成分基本无吸附,且可以有效截留SLN;采用优选的超滤膜测定方法,测得3批蟾酥SLN样品中CBG与RBG的包封率分别为(91.94±0.72)%和(92.38±0.65)%.结论:超滤膜孔径对SLN混悬

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

    DEFF Research Database (Denmark)

    Jørgensen, Anders Richardt


    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...

  15. Toads Give You Warts--Not! (United States)

    Tomasek, Terry; Matthews, Catherine E.


    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 (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. Anxiety and depression assessment and psychological behavior intervention for diabetic patients with skin infection treated by external application of fresh toad skin%糖尿病皮肤感染鲜蟾皮外敷治疗中焦虑抑郁评估与心理行为干预

    Institute of Scientific and Technical Information of China (English)

    李玉; 张晓义; 施美娟


    Objective To explore the influence of psychological behavior intervention on symptoms of anxiety and depression, blood sugar level and therapeutic effect in diabetic patients with skin infection treated by external application of fresh toad skin. Methods 50 diabetic patients with skin infection were selected, and their emotional status were assessed by the comprehensive Hospital Anxiety and Depression measurement scale (HAD). Levels of anxiety, depression and blood sugar were compared before and after the intervention, and the therapeutic effects were compared between patients with external application of fresh toad skin and patients with conventional processing as well. Results Diabetic patients with skin infection had a higher incidence rate of anxiety and depression. After implementation of psychological behavior intervention, the HAD score decreased significantly (P<0.05), the blood sugar level also decreased significantly (P<0.05). Healing condition of infected skin in patients with external application of fresh toad skin was better than patients with conventional processing. Conclusion Application of HAD and psychological behavior intervention in diabetic patients with skin infection can improve prognosis of diabetes combined with skin infection, so it is worthy of clinical attention.%目的 探讨心理行为干预对糖尿病皮肤感染鲜蟾皮外敷患者焦虑抑郁症状、血糖水平和治疗效果的影响.方法 选择50例糖尿病合并皮肤感染患者为研究对象,采用综合医院焦虑抑郁情绪测定量表(HAD)评定其情绪状况,比较干预前后患者的焦虑抑郁及血糖水平情况,并比较采取鲜蟾皮外敷患者和常规处理感染患者的疗效.结果 糖尿病合并皮肤感染患者有较高的焦虑抑郁发生率,实施心理行为干预后HAD评分较干预前有显著降低(P<0.05),血糖水平也相应明显下降(P<0.05),且鲜蟾皮外敷患者较常规处理皮肤感染患者的愈合状况

  18. 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


    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

  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)


    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. Acerca de la localidad tipo y la distribución geográfica de Melanophryniscus klappenbachi Prigione & Langone, 2000 (Anura: Bufonidae

    Directory of Open Access Journals (Sweden)

    Baldo, Diego


    Full Text Available Dada la distribución geográfica de esta especie en Argentina, Prigioni y Langone (op. cit. sugieren que las citas de M. stelzneri fulvoguttatus para las provincias de Santa Fe (Baldo y Arzamendia, 1997 y Santiago del Estero (Basso y Williams, 1996 y para la localidad formoseña de Bartolomé de las Casas (Gallardo, 1961; 1966 debían ser reexaminadas. Del examen del material en el que se basaron dichas citas, concluyo que pertenecen a M. klappenbachi.

  1. A simple and effective auxiliary device for detection of physiologic func-tion on isolated sciatic nerve and gastrocnemius in toads%检测蟾蜍离体坐骨神经和腓肠肌生理功能的简便有效辅助装置

    Institute of Scientific and Technical Information of China (English)

    崔弘; 宋婷婷; 陶媛媛; 幺雨含; 李影; 金惠珍; 李秀国


    目的:设计一种检测蟾蜍离体坐骨神经动作电位和腓肠肌张力的简便有效辅助装置,并分析其实用性。方法:制作由固定坐骨神经和腓肠肌的坐骨神经槽和器官池组成的实验装置(L 形管)。将蟾蜍离体坐骨神经-腓肠肌标本置于 L 形管中,利用 BL-420S 生物机能实验系统检测坐骨神经动作电位和腓肠肌张力。标本随机分为正常对照组、利多卡因神经组和肌肉组,每组6个标本。利多卡因组(0.05、0.2和1 g/L)用相应浓度的利多卡因处理后再用任氏液冲洗,通过分析其对神经和骨骼肌的可逆性麻醉作用,验证装置的实用性。结果:通过将标本固定于 L 形管,能够同时检测坐骨神经动作电位和腓肠肌张力曲线,且易于更换坐骨神经槽和器官池内液体。与对照组比较,0.05和0.2 g/L 利多卡因使坐骨神经的阈强度和最大刺激强度显著性增高(P <0.05),绝对不应期延长(P <0.01),传导速度减慢(P <0.01),1 g/L 利多卡因完全阻滞神经传导。1 g/L 利多卡因使腓肠肌的静息张力显著性升高(P <0.01),最大单收缩幅度显著性降低(P <0.01),但阈强度和最大刺激强度无统计学差异。冲洗后,坐骨神经和腓肠肌的观察指标完全或部分恢复到对照组水平。结论:作为辅助装置,L 形管能够使蟾蜍离体坐骨神经动作电位和腓肠肌收缩性的检测更为便利。%AIM: To design a simple and effective auxiliary device for detection of the compound action poten-tial (CAP) and the force on the isolated sciatic nerve and gastrocnemius in toads, and to investigate its practicability. METHODS: A simple “L” shape device (L tube), which was composed of a nerve chamber and an organ bath, was made for fixing the isolated sciatic nerve and gastrocnemius.After fixing, the sciatic CAP and the gastrocnemius force were

  2. Teaduslikud töötoad osutusid magnetiks / Martin Pau

    Index Scriptorium Estoniae

    Pau, Martin, 1975-


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

  3. Sex chromosome diversity in Armenian toad grasshoppers (Orthoptera, Acridoidea, Pamphagidae) (United States)

    Bugrov, Alexander G.; Jetybayev, Ilyas E.; Karagyan, Gayane H.; Rubtsov, Nicolay B.


    Abstract Although previous cytogenetic analysis of Pamphagidae grasshoppers pointed to considerable karyotype uniformity among most of the species in the family, our study of species from Armenia has discovered other, previously unknown karyotypes, differing from the standard for Pamphagidae mainly in having unusual sets of sex chromosomes. Asiotmethis turritus (Fischer von Waldheim, 1833), Paranocaracris rubripes (Fischer von Waldheim, 1846), and Nocaracris cyanipes (Fischer von Waldheim, 1846) were found to have the karyotype 2n♂=16+neo-XY and 2n♀=16+neo-XX, the neo-X chromosome being the result of centromeric fusion of an ancient acrocentric X chromosome and a large acrocentric autosome. The karyotype of Paranothrotes opacus (Brunner von Wattenwyl, 1882) was found to be 2n♂=14+X1X2Y and 2n♀=14+X1X1X2X2., the result of an additional chromosome rearrangement involving translocation of the neo-Y and another large autosome. Furthermore, evolution of the sex chromosomes in these species has involved different variants of heterochromatinization and miniaturization of the neo-Y. The karyotype of Eremopeza festiva (Saussure, 1884), in turn, appeared to have the standard sex determination system described earlier for Pamphagidae grasshoppers, 2n♂=18+X0 and 2n♀=18+XX, but all the chromosomes of this species were found to have small second C-positive arms. Using fluorescent in situ hybridization (FISH) with 18S rDNA and telomeric (TTAGG)n DNA repeats to yield new data on the structural organization of chromosomes in the species studied, we found that for most of them, clusters of repeats homologous to 18S rDNA localize on two, three or four pairs of autosomes and on the X. In Eremopeza festiva, however, FISH with labelled 18S rDNA painted C-positive regions of all autosomes and the X chromosome; clusters of telomeric repeats localized primarily on the ends of the chromosome arms. Overall, we conclude that the different stages of neo-Y degradation revealed in the Pamphagidae species studied make the family a very promising and useful model for studying sex chromosome evolution. PMID:27186337

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

    DEFF Research Database (Denmark)

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


    rate limiting for the uptake of KCl when Ki is significantly lower than its physiological value. It is concluded that the voltage-activated Cl currents flow through the m.r. cells and that swelling is caused by an uptake of Cl ions from the apical bath and K ions from the serosal bath. Bilateral....... Unilateral exposure to a Cl-free solution did not prevent ouabain-induced cell swelling. It is concluded that m.r. cells have an amiloride-blockable Na conductance in the apical membrane, a ouabain-sensitive Na pump in the basolateral membrane, and a passive Cl permeability in both membranes. From...... the initial rate of ouabain-induced cell volume increase the active Na current carried by a single m.r. cell was estimated to be 9.9 +/- 1.3 pA. Voltage clamping of the preparation in the physiological range of potentials (0 to -100 mV, serosa grounded) resulted in a cell volume increase with a time course...

  5. Disappearance of boreal toads in Colorado: A contaminant investigation (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)....

  6. Sodium recirculation and isotonic transport in toad small intestine

    DEFF Research Database (Denmark)

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


    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...

  7. All-Optical Reversible Hybrid New Gate using TOAD

    Directory of Open Access Journals (Sweden)

    Goutam Kumar Maity


    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.

  8. A Stylistic Analysis of Philip Larkin’s Toads

    Institute of Scientific and Technical Information of China (English)

    Fu Yanli


    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.

  9. A new species of the Rhinella margaritifera species group (Anura, Bufonidae) from the montane forest of the Selva Central, Peru. (United States)

    Moravec, Jiří; Lehr, Edgar; Cusi, Juan Carlos; Córdova, Jesús H; Gvoždík, Václav


    We describe a new species of the bufonid toad genus Rhinella from transition montane forest of the buffer zones of the Yanachaga-Chemillén National Park and the Pui Pui Protected Forest (eastern slopes of Andes, Selva Central, Peru). The new species belongs to the Rhinella margaritifera species group (confirmed by mtDNA data) and differs from all its members by the absence of tympanic membrane and tympanic annulus. It is characterized by medium size (SVL 57.5-65.5 mm, n = 5), moderately developed cranial crests, absence of neural crest of vertebrae, absence of bone protrusion at angle of jaw, presence of lateral rows of enlarged tubercles, and absence of subgular vocal sac and vocal slits in males. In addition, based on the molecular phylogenetic analyses of selected Rhinella species we propose the monophylum containing R. chavin, R. festae, R. macrorhina, R. manu, R. nesiotes, R. rostrata, and R. yanachaga as a new species group under the name Rhinella festae species group.

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

    DEFF Research Database (Denmark)

    Harck, A F; Larsen, Erik Hviid


    mV (apical bath negative). The active sodium currents were eliminated by replacing external Na+ with K+. With [Cl-]o varying between 1.45 mM and 110 mM (gluconate substitution) and [I-]o = 3 mM, the total clamping current (y) and the sum of halide currents (x), estimated from flux measurements, were...

  11. The role of hind limb flexor muscles during swimming in the toad, Bufo marinus. (United States)

    Gillis, Gary B


    Most work examining muscle function during anuran locomotion has focused largely on the roles of major hind limb extensors during jumping and swimming. Nevertheless, the recovery phase of anuran locomotion likely plays a critical role in locomotor performance, especially in the aquatic environment, where flexing limbs can increase drag on the swimming animal. In this study, I use kinematic and electromyographic analyses to explore the roles of four anatomical flexor muscles in the hind limb of Bufo marinus during swimming: m. iliacus externus, a hip flexor; mm. iliofibularis and semitendinosus, knee flexors; and m. tibialis anticus longus, an ankle flexor. Two general questions are addressed: (1) What role, if any, do these flexors play during limb extension? and (2) How do limb flexors control limb flexion? Musculus iliacus externus exhibits a large burst of EMG activity early in limb extension and shows low levels of activity during recovery. Both m. iliofibularis and m. semitendinosus are biphasically active, with relatively short but intense bursts during limb extension followed by longer and typically weaker secondary bursts during recovery. Musculus tibialis anticus longus becomes active mid way through recovery and remains active through the start of extension in the next stroke. In conclusion, flexors at all three joints exhibit some activity during limb extension, indicating that they play a role in mediating limb movements during propulsion. Further, recovery is controlled by a complex pattern of flexor activation timing, but muscle intensities are generally lower, suggesting relatively low force requirements during this phase of swimming.

  12. Soil organic matter content effects on dermal pesticide bioconcentration in American toads (Bufo americanus). (United States)

    Pesticides have been implicated as a major factor in global amphibian declines and may pose great risk to terrestrial phase amphibians moving to and from breeding ponds on agricultural landscapes. Dermal uptake from soil is known to occur in amphibians, but predicting pesticide a...

  13. 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...

  14. Within- and among-population variation in chytridiomycosis-induced mortality in the toad Alytes obstetricans.

    Directory of Open Access Journals (Sweden)

    Ursina Tobler

    Full Text Available BACKGROUND: Chytridiomycosis is a fungal disease linked to local and global extinctions of amphibians. Susceptibility to chytridiomycosis varies greatly between amphibian species, but little is known about between- and within-population variability. However, this kind of variability is the basis for the evolution of tolerance and resistance evolution to disease. METHODOLOGY/PRINCIPAL FINDINGS: In a common garden experiment, we measured mortality after metamorphosis of Alytes obstetricans naturally infected with Batrachochytrium dendrobatidis. Mortality rates differed significantly among populations and ranged from 27 to 90%. Within populations, mortality strongly depended on mass at and time through metamorphosis. CONCLUSIONS/SIGNIFICANCE: Although we cannot rule out that the differences observed resulted from differences in skin microbiota, different pathogen strains or environmental effects experienced by the host or the pathogen prior to the start of the experiment, we argue that genetic differences between populations are a likely source of at least part of this variation. To our knowledge, this is the first study showing differences in survival between and within populations under constant laboratory conditions. Assuming that some of this intraspecific variation has a genetic basis, this may suggest that there is the potential for the evolution of resistance or tolerance, which might allow population persistence.

  15. Physiological and molecular mechanisms of inorganic phosphate handling in the toad Bufo bufo

    DEFF Research Database (Denmark)

    Møbjerg, Nadja; Werner, Andreas; Hansen, Sofie M;


    (i) absorption across skin and intestine. An initial fragment of a NaPi-II type transporter was amplified from kidney, and the full-length sequence was obtained. The protein showed the molecular hallmarks of NaPi-IIb transporters. When expressed in Xenopus oocytes the clone showed unusual pH dependence......, but apparent affinity constants for P(i) and Na(+) were in the range of other NaPi-II transporters. Expression profiling showed that the transporter was present in skin, intestine and kidney. Reverse transcription-polymerase chain reaction assays on dissected renal tubules indicated expression...... in the collecting duct system. Collecting tubules and ducts were isolated, perfused and microelectrode recordings showed electrogenic P(i) transport in apical and basolateral membranes. Taken together, our results show that P(i) is handled by intestine, kidney and skin. The presently cloned NaPi-IIb is a likely...

  16. Nickel affects gill and muscle development in oriental fire-bellied toad (Bombina orientalis) embryos. (United States)

    Park, Chan Jin; Song, Sang Ha; Kim, Dae Han; Gye, Myung Chan


    The developmental toxicity of nickel was examined in the embryos of Bombina orientalis, a common amphibian in Korea. Based on a standard frog embryo teratogenesis assay, the LC50 and EC50 for malformation of nickel after 168h of treatment were 33.8μM and 5.4μM, respectively. At a lethal concentration (100μM), nickel treatment decreased the space between gill filaments and caused epithelial swelling and abnormal fusion of gill filaments. These findings suggest that nickel affects the functional development of gills, leading to embryonic death. At sublethal concentrations (1-10μM), nickel produced multiple embryonic abnormalities, including bent tail and tail dysplasia. At 10μM, nickel significantly decreased tail length and tail muscle fiber density in tadpoles, indicating inhibition of myogenic differentiation. Before hatching, the pre-muscular response to muscular response stages (stages 26-31) were the most sensitive period to nickel with respect to tail muscle development. During these stages, MyoD mRNA was upregulated, whereas myogenic regulatory factor 4 mRNA was downregulated by 0.1μM nickel. Calcium-dependent kinase activities in muscular response stage embryos were significantly decreased by nickel, whereas these activities were restored by exogenous calcium. In tadpoles, 10μM nickel significantly decreased the expression of the myosin heavy chain and the 12/101 muscle marker protein in the tail. Expression was restored by exogenous calcium. Our results indicate that nickel affects muscle development by disrupting calcium-dependent myogenesis in developing B. orientalis embryos.

  17. Cane Toad or Computer Mouse? Real and Computer-Simulated Laboratory Exercises in Physiology Classes (United States)

    West, Jan; Veenstra, Anneke


    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.…

  18. 75 FR 37358 - Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for the Arroyo Toad (United States)


    ... alter the description or distribution of the animals), and the designation of critical habitat for the... extinction of the species. In making that determination, the legislative history is clear that the Secretary... Construction Battalion One Seabees, 1\\st\\ Marine Expeditionary Force Training and Experimentation...

  19. 76 FR 7245 - Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for the Arroyo Toad (United States)


    ...), wild pigs were found to negatively affect almost all aspects of ecosystem structure and function. Their... colonized by invasive weeds. In addition to rooting and habitat alteration, wild pigs prey on reptiles and... threat that feral pigs (Sus scrofa) pose not only to amphibians in general, but in particular to...

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

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Kristensen, P


    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...

  1. Watch Out for the Under Toad : Role and Method of Interdisciplinary Contextualisation in Comparative Legal Research

    NARCIS (Netherlands)

    E. Mak (Elaine)


    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

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

  3. A curious case of herbivory in the common toad Rhinella arenarum during hibernation in captivity conditions

    Directory of Open Access Journals (Sweden)

    Pozzi, Andrea Gabriela


    Full Text Available El objetivo de la presente nota es documentar un comportamiento curioso ocurrido con un grupo de animales adultos de Rhinella arenarum que fueron mantenidos en condiciones de hibernación artificial en el laboratorio durante abril-julio del 2012.

  4. Biomarker Analysis of American Toad (Anaxyrus Americanus) and Grey Tree Frog (Hyla Versicolor) Tadpoles Following Exposure to Atrazine (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...

  5. A curious case of herbivory in the common toad Rhinella arenarum arenarum during hibernation in captivity conditions


    Jungblut, Lucas David; Pozzi, Andrea Gabriela; Paz, Dante Agustin


    Fil: Jungblut, Lucas David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentina; Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina; Fil: Pozzi, Andrea Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad U...

  6. 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


    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...


    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...

  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


    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. Postcranial osteogenesis of the helmeted water toad Calyptocephalella gayi (Neobatrachia: Calyptocephalellidae) with comments on the osteology of australobatrachians. (United States)

    Muzzopappa, Paula; Pugener, L Analía; Báez, Ana María


    Calyptocephalella gayi is one of over 6,000 neobatrachians arranged into two main groups, Hyloides and Ranoides. Phylogenetically, C. gayi is placed in Australobatrachia, a Gondwanan clade that is either the most basal clade of Hyloides or the sister group of Hyloidea, depending on the cladistic hypothesis; as such, this species is a key taxon in the study of the early evolution of Neobatrachia. The ontogeny of the postcranial skeleton of C. gayi is described in this article. The description is based on pattern of chondrification and ossification of skeletal elements in a growth series of tadpoles, on juveniles and adult individuals. Particular attention was devoted to some developmental aspects and morphological traits of the adult skeleton. The body of Presacral Vertebra VIII is formed from three centers of ossification, in contrast to the usual two dorsolateral centers observed in the remaining vertebrae of C. gayi, as well as in most anuran taxa for which the development of the axial skeleton is known. Each half of the pelvic girdle arises from a single cartilaginous element. The early development of the autopodia of both the forelimb and hindlimb includes the presence of an additional chondral element, which occurs during the formation of Distal Carpal 5 and the transient formation of Distal Tarsal 4 before the latter is incorporated in the cartilaginous distal end of the fibular. Some osteological aspects of other australobatrachian anurans also are reviewed (e.g., presence of intervertebral discs) based on reports in the literature, as well as first hand observations. In the course of this study, it became evident that further osteological studies are needed to formulate a clear picture of the evolution of skeletal characters not only within Australobatrachia, but also within Neobatrachia.

  10. 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...

  11. 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.

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

  13. Morphological re-evaluation of the parotoid glands of Bufo ictericus (Amphibia, Anura, Bufonidae)

    NARCIS (Netherlands)

    Almeida, de P.G.; Felsemburgh, F.A.; Azevedo, R.A.; Brito-Gitirana, de L.


    Multicellular glands in the amphibian integument represent a signifi cant evolutionary advance over those of fi shes. Bufonids have parotoid glands, symmetrically disposed in a post-orbital position. Their secretion may contribute to protection against predators and parasites. This study provides a

  14. 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 ...

  15. 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


    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...

  16. 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.


    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

  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



    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 ce...

  18. Comprehensive two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography for analysis of toad skin. (United States)

    Li, Jia-Fu; Yan, Xia; Wu, Yun-Long; Fang, Mei-Juan; Wu, Zhen; Qiu, Ying-Kun


    An analytical two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography (2D NPLC × RPLC) system was constructed with a newly developed thermal evaporation assisted adsorption (TEAA) interface. This novel TEAA interface with heating temperature above solvent boiling point allowed fast removal of organic NPLC solvent and successfully solved the solvent incompatibility problem between NPLC and RPLC. The system achieved rapid on-line solvent exchange between the two dimensions within a short modulation time of 190 s and was applied in the analysis of an extract from the skin of Bufo bufo gargarizans. This is the first time to realize the on-line comprehensive analysis of a moderate polar natural product by coupling NPLC with reversed phase ultra-high performance liquid chromatography (UHPLC). To be highlighted, with the TEAA interface, the 2D NPLC × RPLC system provided excellent resolution and orthogonality (75.2%), when compared with that of 2D RPLC × RPLC.

  19. On-line comprehensive two-dimensional normal-phase liquid chromatography×reversed-phase liquid chromatography for preparative isolation of toad venom. (United States)

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


    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.

  20. 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


    M in skins from animals adapted to distilled water. Both Va and acCl were found to be positively correlated with Isc (r = 0.66 and r = 0.70, respectively). In eight epithelia from animals adapted to dry milieu/tap water Va and acCl were measured with KCl Ringer's on the outside during activation...... V was stepped back to 40 mV, Va instantaneously shifted to -67.8 +/- 3.9 mV while acCl and fRa remained constant during deactivation of GCl. Similar results were obtained in epithelia impaled from the serosal side. In 12 skins from animals adapted to either tap water or distilled water the density...... zero.(ABSTRACT TRUNCATED AT 400 WORDS)...

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



    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 e...

  2. Acute toxicity of the synthetic pyrethroid alpha-cypermethrin on the tadpoles of variable green toad, Bufotes variabilis (Amphibia:Anura

    Directory of Open Access Journals (Sweden)

    Mert Gürkan


    Full Text Available In this study, acute toxic effects of alpha-cypermethrin were investigated in the tadpoles of Bufotes variabilis (Pallas, 1769. Tadpoles at Gosner stage 19 were exposed to 0, 0.1, 5 and 10 µgl-1 of alpha-cypermethrin concentrations for 96 hours. Mortality, the changes in some morphological measurements (snout-vent length, body width, tail length, and wet weight, morphological anomalies and behavioral changes were evaluated at the end of the experiment. The 96 hours LC50 value was calculated as 15.62 µgl-1. Such morphological changes as axial anomaly, visceral edema, deformation of the mouth, and tail deformation were observed in 83% and 95% of the tadpoles in the groups treated with 5 and 10 µgl-1 of alpha-cypermethrin. Behavioral changes such as shortening of the swimming distance and immobility were recorded in all tadpoles exposed to alpha-cypermethrin. When all findings were evaluated totally, it was concluded that alpha-cypermethrin had negative effects on the development of the tadpoles of B. variabilis

  3. 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


    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.

  4. Advertisement call of species of the genus Frostius Cannatella 1986 (Anura: Bufonidae)


    Flora A. Juncá; David L. Röhr; Ricardo Lourenço-de-Moraes; Flávio J.M. Santos; Airan S. Protázio; Ednei A. Mercês; Mirco Solé


    Frostius pernambucensis and F. erythrophthalmus are cryptic bufonid species recognized mainly by the iris color: yellow in F. permambucensis and red in F. erythrophthalmus. However, field studies showed that the iris color of F. erythrophthalmus could vary between yellow and red. To improve the recognition of these species we described the advertisement call of Frostius pernambucensis and Frostius erythrophthalmus and we tested if call characteristics are influenced by temperature, male size ...

  5. Molecular phylogeny and morphometric analyses reveal deep divergence between Amazonia and Atlantic Forest species of Dendrophryniscus. (United States)

    Fouquet, Antoine; Recoder, Renato; Teixeira, Mauro; Cassimiro, José; Amaro, Renata Cecília; Camacho, Agustín; Damasceno, Roberta; Carnaval, Ana Carolina; Moritz, Craig; Rodrigues, Miguel Trefaut


    Dendrophryniscus is an early diverging clade of bufonids represented by few small-bodied species distributed in Amazonia and the Atlantic Forest. We used mitochondrial (414 bp of 12S, 575 bp of 16S genes) and nuclear DNA (785 bp of RAG-1) to investigate phylogenetic relationships and the timing of diversification within the genus. These molecular data were gathered from 23 specimens from 19 populations, including eight out of the 10 nominal species of the genus as well as Rhinella boulengeri. Analyses also included sequences of representatives of 18 other bufonid genera that were publically available. We also examined morphological characters to analyze differences within Dendrophryniscus. We found deep genetic divergence between an Amazonian and an Atlantic Forest clade, dating back to Eocene. Morphological data corroborate this distinction. We thus propose to assign the Amazonian species to a new genus, Amazonella. The species currently named R. boulengeri, which has been previously assigned to the genus Rhamphophryne, is shown to be closely related to Dendrophryniscus species. Our findings illustrate cryptic trends in bufonid morphological evolution, and point to a deep history of persistence and diversification within the Amazonian and Atlantic rainforests. We discuss our results in light of available paleoecological data and the biogeographic patterns observed in other similarly distributed groups.

  6. Rickettsia bellii in Amblyomma rotundatum ticks parasitizing Rhinella jimi from northeastern Brazil. (United States)

    Horta, Mauricio C; Saraiva, Danilo G; Oliveira, Glauber M B; Martins, Thiago F; Labruna, Marcelo B


    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.

  7. 78 FR 17224 - Environmental Impact Statement; Proposed South Puget Sound Prairie Habitat Conservation Plan... (United States)


    ... marmorata affinus), western toad (Bufo boreas), mardon skipper (Polites mardon), Puget blue butterfly... curtus), rose checker mallow (Sidalcea malviflora virgata), small-flowered trillium (Trillium...

  8. A New Horn Toad Megophrys sangzhiensis from Hunan,China (Amphibia,Anura)%中国湖南角蟾科一新种——桑植角蟾

    Institute of Scientific and Technical Information of China (English)

    江建平; 叶昌媛; 费梁


    对采集于湖南桑植县天平山的角蟾标本(CIB200078)与同域分布的相近种尾突角蟾(Megophrys caudoprocta Shen,1994)标本及其他相近种标本比较后发现,该角蟾标本在形态上明显不同于其他物种.其形态特征与尾突角蟾相比:体形小,体长54.7mm;上眼脸外缘三角形突起小;体腹面后部有斑点;犁骨棱弱,末端不膨大,也无犁骨齿;雄性第一、二指背面黑婚刺相对较大,有声囊.与棘指角蟾相比:肛孔上方有一个向后突出的尾突,腹面观可见;雄性第一、二指背面黑婚刺相对较小而密.故将其订为新种:桑植角蟾Megophrys sangzhiensis sp.nov..

  9. Effects of Shaoyao gancao decoction on the compound action potential of toad's sciatic nerves%芍药甘草汤对蟾蜍坐骨神经动作电位的影响

    Institute of Scientific and Technical Information of China (English)

    阮莉莎; 谷勇; 侯杰荣



  10. Effect of guiding electrode spacing on the duration of the toad sciatic nerve trunk action potential%引导电极间距对蟾蜍坐骨神经干动作电位时程的影响

    Institute of Scientific and Technical Information of China (English)




  11. Effect of hyperkalemia on ECGⅡ and monophasic action potential of toad cardiac muscles%蟾蜍高钾血症动物模型实验方法的研究

    Institute of Scientific and Technical Information of China (English)

    陈德森; 彭吉霞; 郭俐宏; 王星文; 朱克刚


    目的 利用在体蟾蜍心脏建立模拟高钾血症(hyperkalemia)动物模型,观察高血钾对蟾蜍Ⅱ导联心电图(electrocardiograph,ECGⅡ)及心室肌单向动作电位(monophasic action potential,MAP)的影响.方法 本实验经咽淋巴囊注射10%氯化钾(KCl)使蟾蜍心肌细胞外液中钾含量急剧升高,同步记录MAP和ECGⅡ.结果 注射10%KCl 10 min后MAP的二相(坪)动作电位时程延长,心率减慢,ECG显示p-R间期延长,QRS波群增宽变低,T波明显高尖,部分动物T波变低或消失.与给药前相比各记录指标差异显著(P<0.05).结论 咽淋巴囊注射10%KCl可致蟾蜍急性高钾血症且ECG改变与哺乳动物高钾血症有相似之处.

  12. Does greater thermal plasticity facilitate range expansion of an invasive terrestrial anuran into higher latitudes? (United States)

    Winwood-Smith, Hugh S; Alton, Lesley A; Franklin, Craig E; White, Craig R


    Temperature has pervasive effects on physiological processes and is critical in setting species distribution limits. Since invading Australia, cane toads have spread rapidly across low latitudes, but slowly into higher latitudes. Low temperature is the likely factor limiting high-latitude advancement. Several previous attempts have been made to predict future cane toad distributions in Australia, but understanding the potential contribution of phenotypic plasticity and adaptation to future range expansion remains challenging. Previous research demonstrates the considerable thermal metabolic plasticity of the cane toad, but suggests limited thermal plasticity of locomotor performance. Additionally, the oxygen-limited thermal tolerance hypothesis predicts that reduced aerobic scope sets thermal limits for ectotherm performance. Metabolic plasticity, locomotor performance and aerobic scope are therefore predicted targets of natural selection as cane toads invade colder regions. We measured these traits at temperatures of 10, 15, 22.5 and 30°C in low- and high-latitude toads acclimated to 15 and 30°C, to test the hypothesis that cane toads have adapted to cooler temperatures. High-latitude toads show increased metabolic plasticity and higher resting metabolic rates at lower temperatures. Burst locomotor performance was worse for high-latitude toads. Other traits showed no regional differences. We conclude that increased metabolic plasticity may facilitate invasion into higher latitudes by maintaining critical physiological functions at lower temperatures.

  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. FCH_ANAXYRUS_CALIFORNICUS_20110209 (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...

  15. Põhjamaised peegeldused Sagadis ja Viinistul / Kersti Sepper ; interv. Reet Varblane

    Index Scriptorium Estoniae

    Sepper, Kersti


    Fenno-Ugria Asutuse korraldatud rahvusvahelisest festivalist "Põhjamaade peegeldused". Sagadi mõisas toimusid skulptuuri ehk maakunsti, keraamika ja graafika töötoad. Nimetatud eesti ja välisosalejad

  16. Filmifestival õpetas ise filme looma / Aarne Mäe

    Index Scriptorium Estoniae

    Mäe, Aarne, 1967-


    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"

  17. 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.;


    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....

  18. 77 FR 9200 - Los Padres National Forest: California; Environmental Impact Statement for the Removal of the... (United States)


    ... getting crews and suppression resources down into the canyons to do it. (2) There are few suitable areas... trampling of arroyo toads and vegetation. Applicators would avoid walking or stepping in water, to...

  19. Instruction Manual and Frog Survey Protocols for Region 1 National Wildlife Refuges, East-side Zone (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,...

  20. 77 FR 21920 - Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To List the Eastern... (United States)


    ...; Keinath and McGee 2005, p. 22), except for the Sangre de Cristo Mountains, Wet Mountains, and Pikes Peak... boreal toad was known to occur in three Rio Arriba County, New Mexico, localities: Lagunitas,...

  1. Detection of the emerging amphibian pathogens Batrachochytrium dendrobatidis and ranavirus in Russia (United States)

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


    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.

  2. Harbingers of Spring (United States)

    Serrao, John


    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)

  3. Valge fungi uus tulemine / Kersti Pikk

    Index Scriptorium Estoniae

    Pikk, Kersti


    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

  4. Inventory of frog species in the South Carolina Sandhills with a focus on the pine barrens treefrog and the gopher frog (United States)

    US Fish and Wildlife Service, Department of the Interior — Proposal is to conduct an inventory of frogs and toads at the Carolina Sandhills NWR and adjoining lands. Special emphasis is to locate the pine barrens treefrog and...

  5. Amphibian abnormalities on National Wildlife Refuges (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. Mitogenome assembly from genomic multiplex libraries: comparison of strategies and novel mitogenomes for five species of frogs. (United States)

    Machado, D J; Lyra, M L; Grant, T


    Next-generation sequencing continues to revolutionize biodiversity studies by generating unprecedented amounts of DNA sequence data for comparative genomic analysis. However, these data are produced as millions or billions of short reads of variable quality that cannot be directly applied in comparative analyses, creating a demand for methods to facilitate assembly. We optimized an in silico strategy to efficiently reconstruct high-quality mitochondrial genomes directly from genomic reads. We tested this strategy using sequences from five species of frogs: Hylodes meridionalis (Hylodidae), Hyloxalus yasuni (Dendrobatidae), Pristimantis fenestratus (Craugastoridae), and Melanophryniscus simplex and Rhinella sp. (Bufonidae). These are the first mitogenomes published for these species, the genera Hylodes, Hyloxalus, Pristimantis, Melanophryniscus and Rhinella, and the families Craugastoridae and Hylodidae. Sequences were generated using only half of one lane of a standard Illumina HiqSeq 2000 flow cell, resulting in fewer than eight million reads. We analysed the reads of Hylodes meridionalis using three different assembly strategies: (1) reference-based (using bowtie2); (2) de novo (using abyss, soapdenovo2 and velvet); and (3) baiting and iterative mapping (using mira and mitobim). Mitogenomes were assembled exclusively with strategy 3, which we employed to assemble the remaining mitogenomes. Annotations were performed with mitos and confirmed by comparison with published amphibian mitochondria. In most cases, we recovered all 13 coding genes, 22 tRNAs, and two ribosomal subunit genes, with minor gene rearrangements. Our results show that few raw reads can be sufficient to generate high-quality scaffolds, making any Illumina machine run using genomic multiplex libraries a potential source of data for organelle assemblies as by-catch.

  7. Disease in a dynamic landscape: host behavior and wildfire reduce amphibian chytrid infection (United States)

    Hossack, Blake R.; Lowe, Winsor H.; Ware, Joy L.; Corn, Paul Stephen


    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.

  8. Influence of caffeine on the isolated heart and action potential of sciatic nerve of toad%咖啡碱对蟾蜍坐骨神经干动作电位和离体心脏活动的影响

    Institute of Scientific and Technical Information of China (English)

    翟心慧; 王志华; 吴清华; 杨洪


    目的:观察咖啡碱对中华大蟾蜍离体坐骨神经干及离体心脏的影响;方法:采用细胞外电极引导法和离体心脏灌流法;结果:咖啡碱处理后,坐骨神经干动作电位幅度显著或极显著高于对照组(P<0.05,P<0.01);咖啡碱处理使心率明显加快,20 mg/ml时显著增加心肌收缩力;结论:咖啡碱有兴奋神经及强心作用.

  9. 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)




  10. Relationship between the genetic structure of the Andean toad Rhinella spinulosa (Anura: Bufonidae and the northern Chile landscape (21°- 24° S Relación entre la estructura genética del sapo andino Rhinella spinulosa (Anura: Bufonidae y el paisaje del norte de Chile (21°- 24° S

    Directory of Open Access Journals (Sweden)



    Full Text Available We analyzed the relationship of landscape and environmental features on the genetic differentiation of Rhinella spinulosa (Wiegmann, 1834 in the Altiplano of Antofagasta (Chile. We performed three types of analyses at different spatial scales: (1 Considering all populations; (2 Grouping populations by watershed and by sub-watershed; and (3 Using the results of a spatial analysis of molecular variation (SAMOVA. Landscape features were incorporated using Geographic Information Systems, with three hypothetical dispersal models: (1 Euclidean distance (null model; (2 Least cost based on wetland locations; and (3 Least cost based on least slopes. We also included differences in temperature, precipitation and altitude among localities. The Akaike information criterion was used to select the best model and the relative importance of each variable in the model was estimated with partial regressions. We found a high genetic differentiation among populations (Fst = 0.693 and isolation by distance (r = 0.767. AMOVA showed that the watersheds explained 8.67 % of the genetic variance and sub-watersheds 35.99 %. At the largest spatial scale, considering all populations, the model that best explained genetic differentiation included Euclidean distance, altitude and annual precipitation. At a smaller scale, in two of three sub-watersheds (Río San Pedro and Salar de Atacama the genetic differentiation was best explained by landscape variables (principally temperature and altitude. At the smallest scale, considering those populations that have diverged recently detected by SAMOVA, the genetic differentiation was best explained by the wetland-based route and annual precipitation. This approach revealed the importance of landscape features in the colonization of R. spinulosa in this zone.Se evaluó la relación entre las características del paisaje y ambientales y la diferenciación genética de Rhinella spinulosa en el altiplano de la Región de Antofagasta (Chile. Para esto se realizaron tres tipos de análisis a diferentes escalas espaciales: (1 considerando todas las poblaciones; (2 agrupando las poblaciones por cuencas y por subcuencas; y (3 utilizando los resultados del análisis espacial de variación molecular (SAMOVA. Las características del paisaje se incorporaron diseñando tres modelos hipotéticos de dispersión con los Sistemas de Información Geográfico: (1 distancia euclidiana (modelo nulo; (2 de menor costo basado en la localización de los humedales; y (3 de menor costo basado en las pendientes menores. Además, se incluyeron las diferencias en temperatura, precipitación y altitud entre localidades. Para seleccionar el modelo que mejor explicara la diferenciación genética se utilizó el Criterio de Información de Akaike y se estimó la importancia relativa de cada variable del modelo seleccionado utilizando regresiones parciales. Se encontró una alta diferenciación genética entre las poblaciones (Fst = 0.693 y un patrón claro de aislamiento por distancia (r = 0.767. El análisis AMOVA mostró que las cuencas explicaron un 8.67 % de la varianza genética y las subcuencas un 35.99 %. A mayor escala espacial, considerando todas las poblaciones, el mejor modelo que explicó la diferenciación genética incluyó las variables distancia euclidiana, altitud y precipitación anual. A menor escala, en dos de las tres subcuencas (Río San Pedro y Salar de Atacama la diferenciación genética fue mejor explicada por variables del paisaje (temperatura y altitud, principalmente. A menor escala, considerando las poblaciones que han divergido recientemente detectadas por SAMOVA, la diferenciación genética fue mejor explicada por la ruta basada en humedales y la precipitación anual. Esta aproximación muestra la importancia de las características del paisaje en la colonización de R. spinulosa en esta zona.

  11. Sublethal effects of endosulfan and diazinon pesticides on glutathione-S-transferase (GST) in various tissues of adult amphibians (Bufo regularis). (United States)

    Ezemonye, Lawrence; Tongo, Isioma


    Glutathione-S-transferase (GST) plays a key role in cellular detoxification of various xenobiotic chemical, especially pesticides. The study was carried out to assess the effects of the organochlorine pesticide, endosulfan and the organophosphate pesticide, diazinon on the activity of GST of different tissues in the African common toad, Bufo regularis. Toads were exposed for 28 days to varying levels of the pesticides: 0.01, 0.02, 0.03 and 0.04 microg L(-1) for the sublethal test. Activity of GST of toads exposed to the pesticides differentially increased significantly with increasing concentrations. The highest enhancement in GST activity was recorded in the liver followed by the brain, serum, GIT and lungs for both pesticide exposures. The differential increase in GST activity was tissue and pesticide specific. Liver GST increased up to 366% in endosulfan exposed toads and 393% in diazinon exposed toads in the highest concentration (0.04 microg L(-1)). Diazinon pesticide from this study proved to be more toxic than endosulfan pesticide.

  12. A New Time-Based Algorithm for Positioning Mobile Terminals in Wireless Networks

    Directory of Open Access Journals (Sweden)

    Francisco Barcelo-Arroyo


    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.

  13. Adrenocortical stress responses influence an invasive vertebrate's fitness in an extreme environment. (United States)

    Jessop, Tim S; Letnic, Mike; Webb, Jonathan K; Dempster, Tim


    Continued range expansion into physiologically challenging environments requires invasive species to maintain adaptive phenotypic performance. The adrenocortical stress response, governed in part by glucocorticoid hormones, influences physiological and behavioural responses of vertebrates to environmental stressors. However, any adaptive role of this response in invasive populations that are expanding into extreme environments is currently unclear. We experimentally manipulated the adrenocortical stress response of invasive cane toads (Rhinella marina) to investigate its effect on phenotypic performance and fitness at the species' range front in the Tanami Desert, Australia. Here, toads are vulnerable to overheating and dehydration during the annual hot-dry season and display elevated plasma corticosterone levels indicative of severe environmental stress. By comparing unmanipulated control toads with toads whose adrenocortical stress response was manipulated to increase acute physiological stress responsiveness, we found that control toads had significantly reduced daily evaporative water loss and higher survival relative to the experimental animals. The adrenocortical stress response hence appears essential in facilitating complex phenotypic performance and setting fitness trajectories of individuals from invasive species during range expansion.

  14. 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...... is the result of my three year PhD study at the National Environmental Research Institute, Kalø, and University of Copenhagen. Funded by NERI, the Danish Research Academy, and the Danish Road Directorate, it has dealt mainly with the effects of traffic and roads on amphibian populations. The Spadefoot toad...... of Spadefoot toads (Pelobates fuscus Laur.) II The effect of road kills on amphibian populations III Simulating viability of a Spadefoot toad (P. fuscus) metapopulation in a landscape fragmented by a road The manuscripts are preceded by a synopsis which sums up the work and puts it into a broader perspective...

  15. 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.

  16. Advanced Subsystems Status Monitor. (United States)


    algorithms in a fashion analogous to human learning , by monitoring the consistency and effec- tiveness of the human operator’s responses. In view of...ou ill t wX Converer O~t~t133 Itectite.-Ot TABLE 16. CONTINUED. PAIM4(IN PSIONIIS MISSION PHASE ENVIROMENT OISPLAV FOWtAl ram AC toad Meter ff DC toad...annoying, or distracting during NOE flight? Eng./X4SN instnuments in new A/C. f, , tic marks difficult and time consuming to Interpret. Electrical

  17. 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


    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.

  18. Green Thumbs: A Kid's Activity Guide to Indoor and Outdoor Gardening. (United States)

    Carlson, Laurie

    This guide contains indoor and outdoor gardening activities for children. The activities teach children how plants live and grow; how the weather, temperature, and seasons affect all living things; how living things come out of seeds and soil; how the birds, earthworms, bees, and toads help in the garden; and how the whole environment works…

  19. Feleucins: Novel Bombinin Precursor-Encoded Nonapeptide Amides from the Skin Secretion of Bombina variegata

    Directory of Open Access Journals (Sweden)

    Bing Bai


    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.

  20. The Forgotten ‘Coastal Forests' of Mtwara, Tanzania: A Biologically Impoverished and Yet Important Ecosystem

    DEFF Research Database (Denmark)

    Wegner, Guilia; Howell, Kim M.; Davenport, Tim R.;


    -Swahilian Brachystegia Woodland. Some Coastal Forest endemic and threatened species, however, occur in the degraded forest patches, such as east coast akalat Sheppardia gunningi, Reichenow's batis Batis mixta reichenowi, spotted flat-lizard Platysaurus maculatus, woodland toad Mertensophryne micranotis and the shrub...

  1. Effect of atrazine and fenitrothion at no-observed-effect-levels (NOEL) on amphibian and mammalian corticosterone-binding-globulin (CBG). (United States)

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


    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.

  2. Kassinurme mägedes toimusid Elendili päeva pidustused ehk Tolkieni sõprade suvelaager / Ilmar Pajumägi

    Index Scriptorium Estoniae

    Pajumägi, Ilmar


    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

  3. The effect of DDT and dieldrin on myelinated nerve fibres

    NARCIS (Netherlands)

    Bercken, J. van den


    The effects of the chlorinated hydrocarbon insecticides, DDT and dieldrin, on myelinated nerve fibres of the clawed toad, Xenopus laevis, were studied by recording compound action nerve fibres, and membrane potentials of single nodes of Ranvier. The effect of DDT (5 × 10−4 M) was found to be exclusi

  4. Negative temperature coefficient of the action of DDT in a sense organ

    NARCIS (Netherlands)

    Bercken, J. van den; Akkermans, L.M.A.


    DDT induced repetitive spontaneuos activity inthe afferent nerve fibers of the lateral-line organ of the clawed toad, Xenopus laevis. The action of DDT increased markedly with lowered temperature. This temperature-effect was easily reversible. The results demonstrate that DDT has a definite negative

  5. Bibliography on Cold Regions Science and Technology. Volume 41. Part 1 (United States)


    toad surfacings. [VERGLIMIT —der Stand der Erfahrungen mit euhemmenden Fahr - bahnbelagszusätzen], Johannes, H., International Road Fede-ation (IRF...meteorology). Meteorologi- cal data, Pollution. 41-3571 Snow depth and incidence of a snowmold disease on mountain big sagebrush. Sturgcs. D.L

  6. 75 FR 42040 - Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition to List the... (United States)


    ... substantial information to indicate the petitioned action may be warranted, and we announced the initiation of... areas they can use for shelter, including burrows, debris piles, spaces under logs or rocks, and areas... benefit Amargosa toads (STORM-OV 2009a, pp. 1-3). Trespass Seep is a low-flow spring site without...

  7. On the presence of Bufo nasicus Werner in Guiana, with a redescription of the species on the basis of recently collected material

    NARCIS (Netherlands)

    Hoogmoed, M.S.


    During research on material recently collected in Guyana and in Venezuelan Guiana, several specimens of the rare toad Bufo nasicus Werner, thus far only known from the holotype without known origin, were discovered. On the basis of this material the species is redescribed and some notes on its natur

  8. Täpne arhitektuur : ACADIA aastakonverents Cooper Unioni arhitektuurikoolis / Veronika Valk

    Index Scriptorium Estoniae

    Valk, Veronika, 1976-


    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

  9. National Science Resources Center Project to Improve Science Teaching in Elementary Schools. Appendix C. Elementary Science Information Database (United States)


    life cycles ; lizards ; reptiles ; snakes ; toads ; turtles AN LET’S HEAR IT FOR HEWPS! is an interdisciplinary approach to the study of reptiles and... thermoregulation AN The SKIN TEMPERATURE module consists of four activity folios, entitled Map Your Temperature, Out in the Cold, The Great Heat

  10. Ermitaazh läheb Amsterdami / Rael Artel

    Index Scriptorium Estoniae

    Artel, Rael, 1980-


    Peterburi Ermitaazhi filiaali avamisest Amstelhofis Hollandis. Avanäitusel veebruaris 2004 saab tutvuda ligi sajakonna Musta mere regioonist pärit antiikkreeka kuldehtega. Filiaali rajamise II faasist. Ermitaazhil on toad Somerset House'is Londonis, kollektsioonide jagamise leping Guggenheimiga New Yorgis ja Kunsthistorisches Museumiga Viinis

  11. Our Zoo to You (United States)

    Wickless, Mimi; Brooks, David W.; Abuloum, Amjad; Mancuso, Brian; Heng-Moss, Tiffany M.; Mayo, Lois


    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,…

  12. 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: [Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096 (China)


    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)

  13. 78 FR 20352 - Endangered and Threatened Species Permit Applications (United States)


    ... Applicant: Bat Conservation International, Austin, Texas. Applicant requests a new permit for research and... (Dermochelys coriacea) Hawksbill (Eretmochelys imbricata) Permit TE-98704A Applicant: Dogs for Conservation... Houston toads (Bufo houstonensis) from the Houston Zoo for work with training dogs how to detect...

  14. Mesoamerican Indigenous Society at the Millennium: Historic and Contemporary Perspectives. Fulbright Hays Summer Seminars Abroad Program, 2000 (Mexico and Guatemala). (United States)

    Wittmann, Teresa

    This curriculum unit combines folk tales and art from Guatemala and Mexico. The unit introduces students to traditional stories and local art of the indigenous people, as well as some details about the culture and geography of the area. It contains four lesson plans: (1) "The Race of Toad and Deer" (Guatemala), mask and play, grades 2-4;…

  15. What Do Amphibians Have to Offer?: Students Monitor and Map Amphibians in Local Pond Habitats (United States)

    Eareckson, Lee Anne


    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…

  16. All about Amphibians. Animal Life for Children. [Videotape]. (United States)


    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…

  17. Responding to Amphibian Loss

    NARCIS (Netherlands)

    Mendelson III, J.R.; Lips, K.R.; Gagliardo, R.W.; Rabb, G.B.; Collins, J.P.; Diffendorfer, J.E.; Daszak, P.; Ibáñez D., R.; Zippel, K.C.; Lawson, D.P.; Wright, K.M.; Stuart, S.N.; Gascon, C.; da Silva, H.R.; Burrowes, P.A.; Joglar, R.L.; La Marca, E.; Lötters, S.; du Preez, L.H.; Weldon, C.; Hyatt, A.; Rodriguez-Mahecha, J.V.; Hunt, S.; Robertson, H.; Lock, B.; Raxworthy, C.J.; Frost, D.R.; Lacy, R.C.; Alford, R.A.; Campbell, J.A.; Parra-Olea, G.; Bolaños, F.; Calvo Domingo, J.J.; Halliday, T.; Murphy, J.B.; Wake, M.H.; Coloma, L.A.; Kuzmin, S.L.; Price, M.S.; Howell, K.M.; Lau, M.; Pethiyagoda, R.; Boone, M.; Lannoo, M.J.; Blaustein, A.R.; Dobson, A.; Griffiths, R.A.; Crump, M.L.; Wake, D.B.; Brodie Jr, E.D.


    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.

  18. 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.


    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

  19. Environmental Assessment: Grade and Pave Shoulders on Runway 15/33 Westover Air Reserve Base, MA (United States)


    s toad, redback salamander , and eastern spotted newt. Common reptiles include the eastern garter 18 snake, northern ringneck snake, black racer...burned grasslands. This allows grassland species to move to suitable habitat and later recolonize the burned habitat once it has regenerated (Vernegaard

  20. JPRS Report. Science & Technology: China. (United States)


    facilitation. I. Introduction There has been great progress since McCulloch and Pitts proposed the first neuron mathematical model for single-neuron...Pattern Recognition and Stimulus Specific Habituation in Toads, Biological Cybernetics, 51(1985), 223-237. 11. McCulloch , W. S., et al., A Logical

  1. Myths. (United States)

    Wheat, Maxwell Corydon, Jr.


    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)

  2. Final Environmental Assessment for National Air & Space Intelligence Center and US Air Force School of Aerospace Medicine Field Training Activities at Wright-Patterson Air Force Base, Ohio (United States)


    amphibians (4 frogs, a toad, and a salamander), 36 fishes, 14 mussels, 35 butterflies, 8 moths, 15 odonates ( dragonflies and damselflies), 6...environments. Most species of amphibians, reptiles, and dragonflies documented at WPAFB have been found in or near aquatic habitats. Habitat specialists

  3. 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


    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.

  4. "mina usun sõna..." : [luuletused] / Maarja Kangro, Mart Kangur, Lauri Kitsnik jt

    Index Scriptorium Estoniae


    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..."

  5. Plasticity in the melanotrope neuroendocrine interface of Xenopus laevis

    NARCIS (Netherlands)

    Jenks, B.G.; Kidane, A.H.; Scheenen, W.J.; Roubos, E.W.


    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

  6. Historical biogeography of Western Palaearctic pelobatid and pelodytid frogs: a molecular phylogenetic perspective

    NARCIS (Netherlands)

    Veith, M.; Fromhage, L.; Kosuch, J.; Vences, M.


    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

  7. Characterization and regulation of voltage-operated Ca2+ channels in neuroendocrine melanotrope cells of Xenopus laevis

    NARCIS (Netherlands)

    Zhang, H.Y.


    To investigate the way by which multiple incoming neurochemical messengers control second messenger systems to evoke an unambiguous neuronal output, melanotrope neuroendocrine cells in the pars intermedia of the pituitary gland of the South African clawed toad Xenopus laevis were studied. Researches

  8. Species delimitation, phylogeny and evolutionary demography of co-distributed, montane frogs in the southern Brazilian Atlantic Forest. (United States)

    Firkowski, Carina R; Bornschein, Marcos R; Ribeiro, Luiz F; Pie, Marcio R


    The Brazilian Atlantic Forest (BAF) is recognized as one of the world's biodiversity hotspots, with even more species per unit of area than the Amazon, however the mechanisms that led to such astonishing diversity are yet to be fully understood. In this study, we investigate the diversification of two co-distributed frog genera associated with montane areas of southern BAF: Melanophryniscus (Bufonidae) and Brachycephalus (Brachycephalidae). Species delimitation methods using mitochondrial and nuclear loci supported the existence of a remarkable number of highly endemic species in each genus, most of which occupy only one or a few adjacent mountaintops. Their timing of diversification was highly congruent, supporting recent speciation events within the past 600 thousand years. Extended Bayesian skyline plots indicate that most populations have remained relatively stable in size across the evolutionary past, with recent growth after 0.15My, suggesting that the drastic changes found in previous studies on lowland frog species were not shared by these montane taxa. These results are consistent with the existence of a montane refugium in southern BAF, allowing species persistence through the climatic shifts experienced along the BAF during the Quaternary.

  9. Optimisation of an oviposition protocol employing human chorionic and pregnant mare serum gonadotropins in the Barred Frog Mixophyes fasciolatus (Myobatrachidae

    Directory of Open Access Journals (Sweden)

    Clulow John


    Full Text Available Abstract Background Protocols for the hormonal induction of ovulation and oviposition are essential tools for managing threatened amphibians with assisted reproduction, but responses vary greatly between species and even broad taxon groups. Consequently, it is necessary to assess effectiveness of such protocols in representative species when new taxa become targets for induction. The threatened genus Mixophyes (family Myobatrachidae has amongst the highest proportion of endangered species of all the Australian amphibians. This study developed and optimised the induction of oviposition in a non-threatened member of this taxon, the great barred frog (Mixophyes fasciolatus. Methods Gravid female M. fasciolatus were induced to oviposit on one or more occasions by administration of human chorionic gonadotropin (hCG with or without priming with pregnant mare serum gonadotropin (PMSG. Treatments involved variations in hormone doses and combinations (administered via injection into the dorsal lymph sacs, and timing of administration. Pituitary homogenates from an unrelated bufonid species (Rhinella marina were also examined with hCG. Results When injected alone, hCG (900 to 1400 IU induced oviposition. However, priming with two time dependent doses of PMSG (50 IU, 25 IU increased responses, with lower doses of hCG (200 IU. Priming increased response rates in females from around 30% (hCG alone to more than 50% (p = 0.035, and up to 67%. Increasing the interval between the first PMSG dose and first hCG dose from 3 to 6 days also produced significant improvement (p Conclusions This study found that M. fasciolatus is amongst the few amphibian species (including Xenopus (Silurana and some bufonids that respond well to the induction of ovulation utilising mammalian gonadotropins (hCG. The optimal protocol for M. fasciolatus involved two priming doses of PMSG (50 IU and 25 IU administered at 6 and 4 days respectively, prior to two doses of hCG (100 IU, 24

  10. Advertisement call of species of the genus Frostius Cannatella 1986 (Anura: Bufonidae

    Directory of Open Access Journals (Sweden)

    Flora A. Juncá


    Full Text Available Frostius pernambucensis and F. erythrophthalmus are cryptic bufonid species recognized mainly by the iris color: yellow in F. permambucensis and red in F. erythrophthalmus. However, field studies showed that the iris color of F. erythrophthalmus could vary between yellow and red. To improve the recognition of these species we described the advertisement call of Frostius pernambucensis and Frostius erythrophthalmus and we tested if call characteristics are influenced by temperature, male size and perch height. We also report on a physical interaction between two males of F. pernambucensis and the associated vocalization, suggesting that F. pernambucensis has not a territorial call or encounter call. Comparing the advertisement calls, the call of F. pernambucensis was lower, shorter and with a smaller number of notes than the call of F. erythrophthalmus. Dominant frequency and fundamental frequency variation of the F. pernambucensis advertisement call were related to the male’s size, while the call emission rate was related to air temperature. However, we could not find relationship among the acoustic characteristic of F. erythrophthalmus and male size or temperature.

  11. Cranial features of dendrobatid larvae (Amphibia: Anura: Dendrobatidae). (United States)

    Haas, A


    The larval neurocranium and visceral arches of seven dendrobatid species representing four genera are described, based on cleared-and-stained and serially sectioned specimens. A variety of characters is shared by all seven species. Larval features do not substantiate the assumption of close ranoid affinities of the Dendrobatidae. Instead dendrobatid larvae share features such as the special quadripartite cartilago suprarostralis, the lack of the larval processus oticus, the presence of three foramina acustica, and the lack of a foramen perilymphaticum accessorius with many bufonoid larvae. The first of these characters is unique to bufonids, hylids, dendrobatids, and some New World leptodactylids; the other characters also occur in pelobatids and are presumably plesiomorphic for the Neobatrachia. The free proximal ends of Ceratobranchialia II and III are an autapomorphy of the Dendrobatidae supporting the monophyly of the family. Some features of the cranium are paedomorphic: low cartilago orbitalis, lack of connection between cartilage orbitalis and otic capsule (most species), and vestigal taeniae tecti. New anatomical terms are introduced.

  12. A model to inform management actions as a response to chytridiomycosis-associated decline (United States)

    Converse, Sarah; Bailey, Larissa L.; Mosher, Brittany A.; Funk, W. Chris; Gerber, Brian D.; Muths, Erin L.


    Decision-analytic models provide forecasts of how systems of interest will respond to management. These models can be parameterized using empirical data, but sometimes require information elicited from experts. When evaluating the effects of disease in species translocation programs, expert judgment is likely to play a role because complete empirical information will rarely be available. We illustrate development of a decision-analytic model built to inform decision-making regarding translocations and other management actions for the boreal toad (Anaxyrus boreas boreas), a species with declines linked to chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd). Using the model, we explored the management implications of major uncertainties in this system, including whether there is a genetic basis for resistance to pathogenic infection by Bd, how translocation can best be implemented, and the effectiveness of efforts to reduce the spread of Bd. Our modeling exercise suggested that while selection for resistance to pathogenic infectionDecision-analytic models provide forecasts of how systems of interest will respond to management. These models can be parameterized using empirical data, but sometimes require information elicited from experts. When evaluating the effects of disease in species translocation programs, expert judgment is likely to play a role because complete empirical information will rarely be available. We illustrate development of a decision-analytic model built to inform decision-making regarding translocations and other management actions for the boreal toad (Anaxyrus boreas boreas), a species with declines linked to chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd). Using the model, we explored the management implications of major uncertainties in this system, including whether there is a genetic basis for resistance to pathogenic infection by Bd, how translocation can best be implemented, and the effectiveness of efforts to

  13. Prostaglandins as mediators of acidification in the urinary bladder of Bufo marinus

    Energy Technology Data Exchange (ETDEWEB)

    Frazier, L.W.; Yorio, T. (Baylor College of Dentistry, Dallas, TX (USA))


    Experiments were performed to determine whether prostaglandins (PG) play a role in H+ and NH4+ excretion in the urinary bladder of Bufo marinus. Ten paired hemibladders from normal toads were mounted in chambers. One was control and the other hemibladder received PGE2 in the serosal medium (10(-5) M). H+ excretion was measured by change in pH in the mucosal fluid and reported in units of nmol (100 mg tissue)-1 (min)-1. NH4+ excretion was measured colorimetrically and reported in the same units. The control group H+ excretion was 8.4 +/- 1.67, while the experimental group was 16.3 +/- 2.64 (P less than 0.01). The NH4+ excretion in the experimental and control group was not significantly different. Bladders from toads in a 48-hr NH4+Cl acidosis (metabolic) did not demonstrate this response to PGE2 (P greater than 0.30). Toads were put in metabolic acidosis by gavaging with 10 ml of 120 mM NH4+Cl 3 x day for 2 days. In another experiment, we measured levels of PG in bladders from control (N) and animals placed in metabolic acidosis (MA). Bladders were removed from the respective toad, homogenized, extracted, and PG separated using high-pressure liquid chromatography and quantified against PG standards. The results are reported in ng (mg tissue)-1. PGE2 fraction in N was 1.09 +/- 0.14 and in MA was 3.21 +/- 0.63 (P less than 0.01). PGF1 alpha, F2 alpha and I2 were not significantly different in N and MA toads. Bladders were also removed from N and MA toads, and incubated in Ringer's solution containing (3H)arachidonic acid (0.2 microCi/ml) at 25 degrees C for 2 hr. Bladders were then extracted for PG and the extracts separated by thin layer chromatography. PG were identified using standards and autoradiography, scraped from plates, and counted in a scintillation detector. The results are reported in cpm/mg tissue x hr +/- SEM.

  14. Evolution of dispersal and life history interact to drive accelerating spread of an invasive species. (United States)

    Perkins, T Alex; Phillips, Benjamin L; Baskett, Marissa L; Hastings, Alan


    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.

  15. 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.


    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.

  16. Amphibian monitoring in the Atchafalaya Basin (United States)

    Waddle, Hardin


    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.

  17. 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.


    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.

  18. [Quod medicina aliis, aliis est acre venenum**--venoms as a source of anticancer agents]. (United States)

    Kucińska, Małgorzata; Ruciński, Piotr; Murias, Marek


    Natural product derived from plants and animals were used in folk medicine for centuries. The venoms produced by animals for hunting of self-defence are rich in bioactive compounds with broad spectrum of biological activity. The papers presents the most promising compounds isolated from venoms of snakes, scorpions and toads. For these compounds both: mechanism of anticancer activity as well as possibilities of clinical use are presented.

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



    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...

  20. Viikingipäevad Käsmus Vana-Jüri neemel

    Index Scriptorium Estoniae


    5.-6. augustil viikingipäevade raames toimivad töötoad: pronksivalu (Harvi Varkki), tinavalu, sepatöö (Mart Salumaa), keraamika ja maapõletus (Eelin Tiidema), nahktöö (Aarne Vaik), pronks- ja hõbeehted (Toomas Mägi alias Mäga), muinasehted (Meelis Säre alias Vanakaru), tekstiil ja puutööd

  1. Säästva renoveerimise meistrikursused : SRIK-Tallinn (Väike-Patarei 3, Tallinn) / Toomas Tallo

    Index Scriptorium Estoniae

    Tallo, Toomas, 1940-


    Rein Tedrekulli koolitustsükkel (loengud Väike-Patarei 3, töötoad Liivalaia 19a): vanade uste restaureerimine - 1. III loeng, 5. III töötuba; vanade akende restaureerimine - 8. III loeng, 12. III töötuba; vana mööbli restaureerimine - 15. III loeng, 19. III töötuba. Siidimaali sissejuhatav kursus: 18. III Väike-Patarei 3 töötuba, mida juhendab kunstnik Evi Vares

  2. Tarbekunstnike ülevaatenäitus

    Index Scriptorium Estoniae


    28. juunist Tarbekunstimuuseumis näitus "Enampakkumine. Eesti tarbekunst 2002". Osaleb 74 kunstnikku. Eksponeeritud Ivo Lille klaasobjekt "Märklaud" (hõbemedal Kanazawas, 2001), Jaan Pärna kuldfiligraanist ehted (hõbemedal Benvenuto Cellini nim. ehtekunsti konkursil), Ülle Raadiku tekstiilkollaazh "Sõnumid olnust" (III preemia triennaalilt "European Quilt", 2000). 10., 11. ja 12. VII töötoad "Kolme päevaga kunstnikuks!"

  3. Effects of Mg2+ on Ca2+ handling by the sarcoplasmic reticulum in skinned skeletal and cardiac muscle fibres. (United States)

    Kabbara, A A; Stephenson, D G


    The influence of myoplasmic Mg2+ (0.05-10 mM) on Ca2+ accumulation (net Ca2+ flux) and Ca2+ uptake (pump-driven Ca2+ influx) by the intact sarcoplasmic reticulum (SR) was studied in skinned fibres from the toad iliofibularis muscle (twitch portion), rat extensor digitorum longus (EDL) muscle (fast twitch), rat soleus muscle (slow twitch) and rat cardiac trabeculae. Ca2+ accumulation was optimal between 1 and 3 mM Mg2+ in toad fibres and reached a plateau between 1 and 10 mM Mg2+ in the rat EDL fibres and between 3 and 10 mM Mg2+ in the rat cardiac fibres. In soleus fibres, optimal Ca2+ accumulation occurred at 10 mM Mg2+. The same trend was obtained with all preparations at 0.3 and 1 microM Ca2+. Experiments with 2,5-di-(tert-butyl)-1,4-benzohydroquinone, a specific inhibitor of the Ca2+ pump, revealed a marked Ca2+ efflux from the SR of toad iliofibularis fibres in the presence of 0.2 microM Ca2+ and 1 mM Mg2+. Further experiments indicated that the SR Ca2+ leak could be blocked by 10 microM ruthenium red without affecting the SR Ca2+ pump and this allowed separation between SR Ca2+ uptake and SR Ca2+ accumulation. At 0.3 microM Ca2+, Ca2+ uptake was optimal with 1 mM Mg2+ in the toad iliofibularis and rat EDL fibres and between 1 and 10 mM Mg2+ in the rat soleus and trabeculae preparations. At higher [Ca2+] (1 microM), Ca2+ uptake was optimal with 1 mM Mg2+ in the iliofibularis fibres and between 1 and 3 mM Mg2+ in the EDL fibres.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Pilot Plant Demonstration of a Sulfide Precipitation Process for Metal-Finishing Wastewater Treatment. (United States)


    TOAD Metal-Finishing Wastewater Treatment System 6 3 View of Portion of Treatment System 7 4 Section of Treatment System, Showing Clearwell 7 5 Filter... Clearwell Effluent Suspended Solids 21 10 Effluent Oil and Grease 22 1 1 Dewatered Sludge Solids 23 12 Operating Time, Wastewater Flows, and Volume of...showing clearwell . S S S - - - - - - - - - - S 0C C0 CL U. * 4 Figure 6. Control panel. c. Flow Equalization. The effluents from the cyanide

  5. 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)



    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.

  6. Maternal Investment Influences Expression of Resource Polymorphism in Amphibians: Implications for the Evolution of Novel Resource-Use Phenotypes



    Maternal effects--where an individual's phenotype is influenced by the phenotype or environment of its mother--are taxonomically and ecologically widespread. Yet, their role in the origin of novel, complex traits remains unclear. Here we investigate the role of maternal effects in influencing the induction of a novel resource-use phenotype. Spadefoot toad tadpoles, Spea multiplicata, often deviate from their normal development and produce a morphologically distinctive carnivore-morph phenotyp...

  7. Environmental Assessment for Alternate Water Supply System, Joint Base Langley-Eustis, Newport News, Virginia (United States)


    occur along stream corridors. The study area is approximately 30 feet above sea level and the topography is flat. The majority of the land in the...Action is in a forest compartment whose management includes performing annual inspections for insect and disease control. Wildlife Resources...Pleistodon spp.) and box turtles (Terrapene carolina). Amphibians observed in the area include Fowler’s toad (Anaxyrus fowleri), marbled

  8. Developmental reversal in neuropeptide Y action on feeding in an amphibian. (United States)

    Crespi, Erica J; Denver, Robert J


    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.

  9. Environmental Assessment: Tree Removal to Improve FAA Radar Coverage, Youngstown Air Reserve Station (United States)


    Trees would ultimately regenerate , particularly if aggressive invasive species were controlled . The Proposed Action would result in a major loss of the...include toads, frogs, and salamanders . A wide range of birds from Canada geese to common song birds are found within and near the Project Study Area...drainage. As the vegetation at the site regenerates over a three to five or more year period, site hydrology would return to the current conditions

  10. Environmental Assessment of the Construction of the Joint Use Small Arms Range for the 934th Airlift Wing at Minneapolis-St. paul International Airport Air Reserve Station, Minnesota (United States)


    design must preclude escape of both direct-fired projectiles and ricochets. “Blue sky ” should not be visible from any firing position or as one...travels downrange towards the target. Overhead baffles prevent “blue sky ” visibility. The bullet trap at the existing small arms range has exposed... starling (Sturnus vulgaris). Other species might include the common garter snake (Thamnophis sirtalis) and the American toad (Bufo americanus) (934 AW

  11. Environmental Assessment of Proposed Mixed-Use Business Park on an Enchanced Use Lease at Grand Forks Air Force Base, North Dakota (United States)


    Although no formal survey has been conducted for amphibians and reptiles on the base, two reptiles and four amphibians have been observed at...are the American toad (Bufo americanus), and wood frog (Rana sylvatica). Reptiles observed on base include the common garter snake (Thamnophis...original peoples of North and South America (including Central America ) and who maintain tribal affiliation or community attachment;  Asian – A

  12. Immediate and lag effects of pesticide exposure on parasite resistance in larval amphibians. (United States)

    Pochini, Katherine M; Hoverman, Jason T


    Across host-parasite systems, there is evidence that pesticide exposure increases parasite loads and mortality following infection. However, whether these effects are driven by reductions in host resistance to infection or slower rates of parasite clearance is often unclear. Using controlled laboratory experiments, we examined the ability of larval northern leopard frogs (Lithobates pipiens) and American toads (Anaxyrus americanus) to resist and clear trematode (Echinoparyphium sp.) infections following exposure to the insecticide carbaryl. Northern leopard frogs exposed to 1 mg L-1 of carbaryl had 61% higher parasite loads compared with unexposed individuals, while there was no immediate effect of carbaryl on parasite encystment in American toads. However, when tadpoles were exposed to carbaryl and moved to freshwater for 14 days before the parasite challenge, we recovered 37 and 63% more parasites from carbaryl-exposed northern leopard frogs and American toads, respectively, compared with the control. No effects on clearance were found for either species. Collectively, our results suggest that pesticide exposure can reduce the ability of amphibians to resist parasite infections and that these effects can persist weeks following exposure. It is critical for researchers to incorporate species interactions into toxicity studies to improve our understanding of how contaminants affect ecological communities.

  13. Effect of chloride on Ca2+ release from the sarcoplasmic reticulum of mechanically skinned skeletal muscle fibres. (United States)

    Coonan, J R; Lamb, G D


    The effect of intracellular Cl- on Ca2+ release in mechanically skinned fibres of rat extensor digitorum longus (EDL) and toad iliofibularis muscles was examined under physiological conditions of myoplasmic [Mg2+] and [ATP] and sarcoplasmic reticulum (SR) Ca2+ loading. Both in rat and toad fibres, the presence of 20 mM Cl- in the myoplasm increased Ca2+ leakage from the SR at pCa (i.e. -log10 [Ca2+]) 6.7, but not at pCa 8. Ca2+ uptake was not significantly affected by the presence of Cl-. This Ca2+-dependent effect of Cl- on Ca2+ leakage was most likely due to a direct action on the ryanodine receptor/Ca2+ release channel, and could influence channel sensitivity and the resting [Ca2+] in muscle fibres in vivo. In contrast to this effect, acute addition of 20 mM Cl- to the myoplasm caused a 40-50% reduction in Ca2+ release in response to a low caffeine concentration both in toad and rat fibres. One possible explanation for this latter effect is that the addition of Cl- induces a potential across the SR (lumen negative) which might reduce Ca2+ release via several different mechanisms.

  14. Sympatric Masticophis flagellum and Coluber constrictor select vertebrate prey at different levels of taxonomy (United States)

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


    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.

  15. Analgesia Synergism of Essential Oil from Pericarp of Zanthoxylum schinifolium and Verapamil

    Directory of Open Access Journals (Sweden)

    Gao Wu


    Full Text Available Objective. To evaluate the synergistic analgesic effect of essential oil of Zanthoxylum schinifolium Sieb. et Zucc. (EOZ and verapamil (Ver. Method. The qualitative and quantitative composition of EOZ were determined with gas chromatography/Mass spectrometer. The interaction between EOZ and Ver in antinociceptive activity was evaluated by using acetic acid-induced writhing, hot plate, and tail flick tests in mice and in isolated toad sciatic nerve test. Results. Linalool, limonene, and sabinene are the major components of EOZ. EOZ (middle-dose: 40 mg·kg−1, high-dose: 80 mg·kg−1 and EOZ + Ver (Each dose group have remarkable analgesic effects on pain in mice induced by acetic acid-induced writhing, hot plate, and tail flick tests. Low-dose EOZ (20 mg·kg−1 had no analgesic action, but when it is combined with Ver it has shown significant antinociception. Verapamil has a faint analgesic effect but was not able to inhibit action potential transmission in toad sciatic nerve. EOZ (0.2% and EOZ + Ver (0.2% + 0.05% also inhibited action potential transmission in toad sciatic nerve. Combination of EOZ with Ver had a greater analgesic effect and inhibition of nerve action potential transmission compared to its components EOZ and Ver. Conclusion. The combination of EOZ with Ver produces a synergistic analgesic effect.

  16. 外用蟾酥在肿瘤治疗中的应用%Topical application of venenum bufonis application in tumor treatment

    Institute of Scientific and Technical Information of China (English)

    殷子斐; 张慧卿; 苏永华


    Toad venom, as a chinese traditional medicine, can relieve cancer pain and treat skin cancer, cervical cancer and penis cancer effectively when externally used, which has been demonstrated by a great deal of clinical researches. Toad venom is of vital importance in the treatment of cancer, and its clinical application is worth to be introduced. However, the dosage and indications of toad venom should be strictly controlled in order to ensure the safe and effective drug-use in pa-tien ts.%综述了外用蟾酥在治疗体表肿瘤及癌痛中的应用,认为其对皮肤癌、宫颈癌、阴茎癌等肿瘤具有良好治疗作用,在肿瘤治疗中具有重要意义,但在临床外用蟾酥时,需要控制剂量,并严格掌握其适应症,保证临床用药的安全有效.

  17. 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


    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...... active Cl- uptake in fresh water by creating a favourable gradient for an apical HCO3- exit in exchange for external Cl-. The data also suggest that a carbonic anhydrase activity provides H+ and HCO3- for apically co-expressed proton pumps and Cl-/HCO3- exchangers....... of a rheogenic proton pump. Cl- influx was 37.4-7.5 pmol·cm-2·s-1 (n=14) in frog skin and 19.5-3.5 pmol·cm-2·s-1 (n=11) in toad skin. In toad skin, the mean Cl- flux ratio was larger than expected for simple electro-diffusion. In 8 of 11 sets of paired skins, influx was greater than the efflux indicating active......-type proton pump (V-ATPase) inhibitor, significantly reduced proton secretion in frog skin. In addition, concanamycin A (1 µM) significantly reduced Cl- influx in frog skin. We suggest that the active proton secretion and Cl- influx are coupled. We hypothesise that an apical V-ATPase is capable of energising...

  18. OASIS is Automated Statistical Inference for Segmentation, with applications to multiple sclerosis lesion segmentation in MRI. (United States)

    Sweeney, Elizabeth M; Shinohara, Russell T; Shiee, Navid; Mateen, Farrah J; Chudgar, Avni A; Cuzzocreo, Jennifer L; Calabresi, Peter A; Pham, Dzung L; Reich, Daniel S; Crainiceanu, Ciprian M


    Magnetic resonance imaging (MRI) can be used to detect lesions in the brains of multiple sclerosis (MS) patients and is essential for diagnosing the disease and monitoring its progression. In practice, lesion load is often quantified by either manual or semi-automated segmentation of MRI, which is time-consuming, costly, and associated with large inter- and intra-observer variability. We propose OASIS is Automated Statistical Inference for Segmentation (OASIS), an automated statistical method for segmenting MS lesions in MRI studies. We use logistic regression models incorporating multiple MRI modalities to estimate voxel-level probabilities of lesion presence. Intensity-normalized T1-weighted, T2-weighted, fluid-attenuated inversion recovery and proton density volumes from 131 MRI studies (98 MS subjects, 33 healthy subjects) with manual lesion segmentations were used to train and validate our model. Within this set, OASIS detected lesions with a partial area under the receiver operating characteristic curve for clinically relevant false positive rates of 1% and below of 0.59% (95% CI; [0.50%, 0.67%]) at the voxel level. An experienced MS neuroradiologist compared these segmentations to those produced by LesionTOADS, an image segmentation software that provides segmentation of both lesions and normal brain structures. For lesions, OASIS out-performed LesionTOADS in 74% (95% CI: [65%, 82%]) of cases for the 98 MS subjects. To further validate the method, we applied OASIS to 169 MRI studies acquired at a separate center. The neuroradiologist again compared the OASIS segmentations to those from LesionTOADS. For lesions, OASIS ranked higher than LesionTOADS in 77% (95% CI: [71%, 83%]) of cases. For a randomly selected subset of 50 of these studies, one additional radiologist and one neurologist also scored the images. Within this set, the neuroradiologist ranked OASIS higher than LesionTOADS in 76% (95% CI: [64%, 88%]) of cases, the neurologist 66% (95% CI: [52%, 78

  19. Oscillation of an anuran hybrid zone: morphological evidence spanning 50 years.

    Directory of Open Access Journals (Sweden)

    Jean-Sébastien Roy

    Full Text Available BACKGROUND: The hybrid zone between the primarily forest-dwelling American toad, Anaxyrus americanus, and the prairie-adapted Canadian toad, A. hemiophrys, in southeastern Manitoba is known to have shifted its position during the past 50 years. Hybrid zones are areas of interbreeding between species and their movement across a landscape should reflect their underlying dynamics and environmental change. However, empirical demonstrations of hybrid zone movements over long periods of time are rare. This hybrid zone is dominated by individuals of intermediate morphology and genetic composition. We sought to determine if it had continued to move and if that movement was associated with shifts in habitat, as predicted. METHODOLOGY/PRINCIPLE FINDINGS: We used variation in the toads' most diagnostic morphological feature, the separation between their interorbital cranial crests, to determine the geographic position of the hybrid zone center at four times between 1960 and 2009 using maximum likelihood methods. The hybrid zone center moved west by 38 km over 19 years and then east again by 10 km over the succeeding 29 years. The position of the hybrid zone did not track either the direction or the magnitude of movement of the forest-prairie habitat transition over the same time period. CONCLUSIONS/SIGNIFICANCE: This is the first reported evidence of oscillation in the position of a hybrid zone. The back and forth movement indicates that neither species maintains a selective advantage over the other in the long term. However, the movement of the hybrid zone was not bounded by the breadth of the habitat transition. Its oscillation suggests that the hybrid zone is better described as being elastically tethered to the habitat transition.

  20. Effects of Pesticide Mixtures on Host-Pathogen Dynamics of the Amphibian Chytrid Fungus. (United States)

    Buck, Julia C; Hua, Jessica; Brogan, William R; Dang, Trang D; Urbina, Jenny; Bendis, Randall J; Stoler, Aaron B; Blaustein, Andrew R; Relyea, Rick A


    Anthropogenic and natural stressors often interact to affect organisms. Amphibian populations are undergoing unprecedented declines and extinctions with pesticides and emerging infectious diseases implicated as causal factors. Although these factors often co-occur, their effects on amphibians are usually examined in isolation. We hypothesized that exposure of larval and metamorphic amphibians to ecologically relevant concentrations of pesticide mixtures would increase their post-metamorphic susceptibility to the fungus Batrachochytrium dendrobatidis (Bd), a pathogen that has contributed to amphibian population declines worldwide. We exposed five anuran species (Pacific treefrog, Pseudacris regilla; spring peeper, Pseudacris crucifer; Cascades frog, Rana cascadae; northern leopard frog, Lithobates pipiens; and western toad, Anaxyrus boreas) from three families to mixtures of four common insecticides (chlorpyrifos, carbaryl, permethrin, and endosulfan) or herbicides (glyphosate, acetochlor, atrazine, and 2,4-D) or a control treatment, either as tadpoles or as newly metamorphic individuals (metamorphs). Subsequently, we exposed animals to Bd or a control inoculate after metamorphosis and compared survival and Bd load. Bd exposure significantly increased mortality in Pacific treefrogs, spring peepers, and western toads, but not in Cascades frogs or northern leopard frogs. However, the effects of pesticide exposure on mortality were negligible, regardless of the timing of exposure. Bd load varied considerably across species; Pacific treefrogs, spring peepers, and western toads had the highest loads, whereas Cascades frogs and northern leopard frogs had the lowest loads. The influence of pesticide exposure on Bd load depended on the amphibian species, timing of pesticide exposure, and the particular pesticide treatment. Our results suggest that exposure to realistic pesticide concentrations has minimal effects on Bd-induced mortality, but can alter Bd load. This result

  1. Infection and transmission heterogeneity of a multi-host pathogen (Batrachochytrium dendrobatidis) within an amphibian community. (United States)

    Fernández-Beaskoetxea, S; Bosch, J; Bielby, J


    The majority of parasites infect multiple hosts. As the outcome of the infection is different in each of them, most studies of wildlife disease focus on the few species that suffer the most severe consequences. However, the role that each host plays in the persistence and transmission of infection can be crucial to understanding the spread of a parasite and the risk it poses to the community. Current theory predicts that certain host species can modulate the infection in other species by amplifying or diluting both infection prevalence and infection intensity, both of which have implications for disease risk within those communities. The fungus Batrachochytrium dendrobatidis (Bd), the causal agent of the disease chytridiomycosis, has caused global amphibian population declines and extinctions. However, not all infected species are affected equally, and thus Bd is a good example of a multi-host pathogen that must ultimately be studied with a community approach. To test whether the common midwife toad Alytes obstetricans is a reservoir and possible amplifier of infection of other species, we used experimental approaches in captive and wild populations to determine the effect of common midwife toad larvae on infection of other amphibian species found in the Peñalara Massif, Spain. We observed that the most widely and heavily infected species, the common midwife toad, may be amplifying the infection loads in other species, all of which have different degrees of susceptibility to Bd infection. Our results have important implications for performing mitigation actions focused on potential 'amplifier' hosts and for better understanding the mechanisms of Bd transmission.

  2. Diversity of pulsed-field gel electrophoresis pulsotypes, serovars, and antibiotic resistance among Salmonella isolates from wild amphibians and reptiles in the California Central Coast. (United States)

    Gorski, Lisa; Jay-Russell, Michele T; Liang, Anita S; Walker, Samarpita; Bengson, Yingjia; Govoni, Jessica; Mandrell, Robert E


    A survey of cold-blooded vertebrates and associated surface waters in a produce-growing region on the Central California Coast was done between May and September 2011 to determine the diversity of Salmonella. Samples from 460 amphibians and reptiles and 119 water samples were collected and cultured for Salmonella. Animals sampled were frogs (n=331), lizards (n=59), newts (n=5), salamanders (n=6), snakes (n=39), and toads (n=20). Salmonella was isolated from 37 individual animals, including frogs, lizards, snakes, and toads. Snakes were the most likely to contain Salmonella, with 59% testing positive followed by 15.3% of lizards, 5% of toads, and 1.2% of frogs. Fifteen water samples (12.6%) were positive. Twenty-two different serovars were identified, and the majority of isolates were S. enterica subsp. IIIb, with subsp. I, II, and IIIa also found. The serovar isolated most frequently was S. enterica subsp. IIIb 16:z₁₀:e,n,x,z₁₅, from snakes and frogs in five different locations. S. enterica subsp. I serovar Typhimurium and the monophasic I 6,8:d:- were isolated from water, and subspecies I Duisburg and its variants were found in animals and water. Some samples contained more than one type of Salmonella. Analysis of pulsed-field gel electrophoresis pulsotypes indicated that some strains persisted in animals and water collected from the same location. Sixty-six isolates displayed antibiotic resistance, with 27 isolates resistant to more than one antibiotic, including a subspecies IIIb isolate from snake having resistance to five different antibiotics. Twenty-three isolates were resistant to more than one class of antibiotic, and six isolates were resistant to three classes. While these subspecies of IIIa and IIIb cause fewer instances of human illness, they may serve as reservoirs of antibiotic resistance, determinants in the environment, and be sources of contamination of leafy greens associated with product recalls.

  3. Conserving Prairie Pothole Region wetlands and surrounding grasslands: evaluating effects on amphibians (United States)

    Mushet, David M.; Neau, Jordan L.


    The maintenance of viable and genetically diverse populations of amphibians in the Prairie Pothole Region of the United States depends on upland as well as wetland over-wintering and landscape level habitat features. Prairie pothole wetlands provide important amphibian breeding habitat while grasslands surrounding these wetlands provide foraging habitat for adults, overwintering habitat for some species, and important connectivity among breeding wetlands. Grasslands surrounding wetlands were found to be especially important for wood frogs and northern leopard frogs, while croplands dominated habitat utilized by Great Plains toads and Woodhouse’s toads. Habitat suitability mapping highlighted (1) the influence of deep-water overwintering wetlands on suitable habitat for four of five anuran species encountered; (2) the lack of overlap between areas of core habitat for both the northern leopard frog and wood frog compared to the core habitat for both toad species; and (3) the importance of conservation programs in providing grassland components of northern leopard frog and wood frog habitat. Currently, there are approximately 7.2 million acres (2.9 million hectares, ha) of habitat in the PPR identified as suitable for amphibians. WRP and CRP wetland and grassland habitats accounted for approximately 1.9 million acres (0.75 million ha) or 26 percent of this total area. Continued loss of amphibian habitat resulting from an ongoing trend of returning PPR conservation lands to crop production, will likely have significant negative effects on the region’s ability to maintain amphibian biodiversity. Conversely, increases in conservation wetlands and surrounding grasslands on the PPR landscape have great potential to positively influence the region’s amphibian populations.

  4. Distribution and environmental limitations of an amphibian pathogen in the Rocky Mountains, USA (United States)

    Muths, E.; Pilliod, D.S.; Livo, L.J.


    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.

  5. Effects of Pesticide Mixtures on Host-Pathogen Dynamics of the Amphibian Chytrid Fungus.

    Directory of Open Access Journals (Sweden)

    Julia C Buck

    Full Text Available Anthropogenic and natural stressors often interact to affect organisms. Amphibian populations are undergoing unprecedented declines and extinctions with pesticides and emerging infectious diseases implicated as causal factors. Although these factors often co-occur, their effects on amphibians are usually examined in isolation. We hypothesized that exposure of larval and metamorphic amphibians to ecologically relevant concentrations of pesticide mixtures would increase their post-metamorphic susceptibility to the fungus Batrachochytrium dendrobatidis (Bd, a pathogen that has contributed to amphibian population declines worldwide. We exposed five anuran species (Pacific treefrog, Pseudacris regilla; spring peeper, Pseudacris crucifer; Cascades frog, Rana cascadae; northern leopard frog, Lithobates pipiens; and western toad, Anaxyrus boreas from three families to mixtures of four common insecticides (chlorpyrifos, carbaryl, permethrin, and endosulfan or herbicides (glyphosate, acetochlor, atrazine, and 2,4-D or a control treatment, either as tadpoles or as newly metamorphic individuals (metamorphs. Subsequently, we exposed animals to Bd or a control inoculate after metamorphosis and compared survival and Bd load. Bd exposure significantly increased mortality in Pacific treefrogs, spring peepers, and western toads, but not in Cascades frogs or northern leopard frogs. However, the effects of pesticide exposure on mortality were negligible, regardless of the timing of exposure. Bd load varied considerably across species; Pacific treefrogs, spring peepers, and western toads had the highest loads, whereas Cascades frogs and northern leopard frogs had the lowest loads. The influence of pesticide exposure on Bd load depended on the amphibian species, timing of pesticide exposure, and the particular pesticide treatment. Our results suggest that exposure to realistic pesticide concentrations has minimal effects on Bd-induced mortality, but can alter Bd load

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

    Directory of Open Access Journals (Sweden)

    D Cavallo


    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.

  7. The lateral intercellular space as osmotic coupling compartment in isotonic transport

    DEFF Research Database (Denmark)

    Larsen, E.H.; Willumsen, N.J.; Mobjerg, N.;


    solute-water coupling: stoichiometric coupling at the molecular level by transport proteins like SGLT1, electro-osmosis and a 'junctional fluid transfer mechanism'. Convection-diffusion out of the lateral space constitutes the fundamental problem of isotonic transport by making the emerging fluid...... at transepithelial osmotic equilibrium as observed in toad skin epithelium in vitro. Our conclusions are further developed for discussing their application to solute-solvent coupling in other vertebrate epithelia such as small intestine, proximal tubule of glomerular kidney and gallbladder. Evidence is discussed...

  8. Terahertz optical asymmetric demultiplexer based tree-net architecture for all-optical conversion scheme from binary to its other 2n radix based form

    Institute of Scientific and Technical Information of China (English)


    To exploit the parallelism of optics in data processing,a suitable number system and an efficient encoding/decoding scheme for handling the data are very essential.In the field of optical computing and parallel information processing,several number systems like binary,quaternary,octal,hexadecimal,etc.have been used for different arithmetic and algebraic operations.Here,we have proposed an all-optical conversion scheme from its binary to its other 2n radix based form with the help of terahertz optical asymmetric demultiplexer (TOAD) based tree-net architecture.

  9. Electrophysiologic similarities of overdose between digoxin and bufadienolides found in a Chinese aphrodisiac. (United States)

    Bressman, Maxwell; Repplinger, Daniel; Slater, William; Patt, Mitchell


    Classically derived from toad venom, bufadienolides are a group of cardioactive steroids with properties similar to digoxin. Some traditional Chinese medications, including several aphrodisiacs, contain bufadienolides. Owing to their physiologic similarities to digoxin, bufadienolides have been shown to produce a toxic profile similar to that of digoxin and there have been multiple case reports of the use of these aphrodisiacs resulting in death. This report will describe a case that illustrates the electrophysiologic similarities between bufadienolide toxicity and digoxin toxicity as well as the treatment of bufadienolide toxicity.

  10. Amphibians and disease: Implications for conservation in the Greater Yellowstone Ecosystem (United States)

    Corn, P.S.


    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).

  11. Investigating potential for effects of environmental endocrine disrupters on wild populations of amphibians in UK and Japan: status of historical databases and review of methods. (United States)

    Pickford, Daniel B; Larroze, Severine; Takase, Minoru; Mitsui, Naoko; Tooi, Osamu; Santo, Noriaki


    Concern over global declines among amphibians has resulted in increased interest in the effects of environmental contaminants on amphibian populations, and more recently, this has stimulated research on the potential adverse effects of environmental endocrine disrupters in amphibians. Laboratory studies of the effects of single chemicals on endocrine-relevant endpoints in amphibian, mainly anuran, models are valuable in characterizing sensitivity at the individual level and may yield useful bioassays for screening chemicals for endocrine toxicity (for example, thyroid disrupting activity). Nevertheless, in the UK and Japan as in many other countries, it has yet to be demonstrated unequivocally that the exposure of native amphibians to endocrine disrupting environmental contaminants results in adverse effects at the population level. Assessing the potential of such effects is likely to require an ecoepidemiological approach to investigate associations between predicted or actual exposure of amphibians to (endocrine disrupting) environmental contaminants and biologically meaningful responses at the population level. In turn, this demands recent but relatively long-term population trend data. We review two potential sources of such data for widespread UK anurans that could be used in such investigations: records for common frogs and common toads in several databases maintained by the Biological Records Centre (UK Government Centre for Ecology and Hydrology), and adult toad count data from 'Toads on Roads' schemes registered with the UK wildlife charity 'Froglife'. There were little abundance data in the BRC databases that could be used for this purpose, while count data from the Toads on Roads schemes is potentially confounded by the effects of local topology on the detection probabilities and operation of nonchemical anthropogenic stressors. For Japan, local and regional surveys of amphibians and national ecological censuses gathering amphibian data were reviewed to

  12. Embryotoxicity of lead on Bufo arenarum

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  13. 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....... MRI was done using a Philips Achieva 1.5 T system and CT was performed using a Siemens Somatom system. Axial and sagittal slices were acquired using standard T1w and T2w MRI sequences, and visualization was made using the Mistar software (Apollo Imaging Technology, Melbourne, Australia). Images were...

  14. The comparative analyze of the trophic spectrum of two Bombina variegata populations from Baita Plai (Bihor county, Romania

    Directory of Open Access Journals (Sweden)

    Violeta I. PETER


    Full Text Available The present study brings completions to the existing data about the trophic spectrum of the yellow-bellied toad. Its diet is composed of prey taxa belonging to invertebrates: Coleoptera, Hymenoptera Formicida, Nematocera larva, Homoptera Aphids, Colembola as well as Crustacea Cladocera. Beside animal preys in the stomachs contents there were identified vegetal and shed-skins. The most significant differences were recorded when we compared the diet composition of the individuals belonging to the two studied habitats, having in view the very obvious difference of their aspect. Beside these, we also identified differences determined by the sex and size of the individuals or by the collecting period.

  15. New species of Parapharyngodon (Nematoda: Pharyngodonidae) in Rhinella marina (Anura: Bufonidae) from Grenada, West Indies (United States)

    Bursey, Charles; Drake, Michael; Cole, Rebecca; Sterner, Mauritz; Pinckney, Rhonda; Zieger, Ulrike


    Parapharyngodon grenadaensis n. sp. (Nematoda: Pharyngodonidae) from the large intestine of the cane toad, Rhinella marina, is described and illustrated. Parapharyngodon grenadaensis n. sp. is the 48th species assigned to the genus and the 16th species from the Neotropical region. It differs from other species in the genus by possessing 4 pairs of caudal papillae, an echinate anterior cloacal lip, and a blunt spicule of 67–104 μm. This is only the second report of R. marina harboring a species of Parapharyngodon.

  16. 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

  17. Cardiovascular physiology and diseases of amphibians. (United States)

    Heinz-Taheny, Kathleen M


    The class Amphibia includes three orders of amphibians: the anurans (frogs and toads), urodeles (salamanders, axolotls, and newts), and caecilians. The diversity of lifestyles across these three orders has accompanying differences in the cardiovascular anatomy and physiology allowing for adaptations to aquatic or terrestrial habitats, pulmonic or gill respiration, hibernation, and body elongation (in the caecilian). This article provides a review of amphibian cardiovascular anatomy and physiology with discussion of unique species adaptations. In addition, amphibians as cardiovascular animal models and commonly encountered natural diseases are covered.

  18. The Amphibian Research and Monitoring Initiative in the Pacific Northwest (United States)

    Adams, Michael J.


    Amphibians have been disappearing from many locations around the world with reports of declines increasing in recent decades. Some of the most dramatic declines have occurred in areas that were thought to be protected from human disturbance. For example, the once-common boreal toad has virtually disappeared from Rocky Mountain National Park in Colorado. Although there has been debate on whether these declines represent a short-term fluctuation in populations or major sustained losses, there is now general scientific consensus that something really is amiss with amphibian populations.

  19. 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


    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.

  20. Animal reintroductions: an innovative assessment of survival (United States)

    Muths, Erin L.; Bailey, Larissa L.; Watry, Mary Kay


    Quantitative evaluations of reintroductions are infrequent and assessments of milestones reached before a project is completed, or abandoned due to lack of funding, are rare. However, such assessments, which are promoted in adaptive management frameworks, are critical. Quantification can provide defensible estimates of biological success, such as the number of survivors from a released cohort, with associated cost per animal. It is unlikely that the global issues of endangered wildlife and population declines will abate, therefore, assurance colonies and reintroductions are likely to become more common. If such endeavors are to be successful biologically or achieve adequate funding, implementation must be more rigorous and accountable. We use a novel application of a multistate, robust design capture-recapture model to estimate survival of reintroduced tadpoles through metamorphosis (i.e., the number of individuals emerging from the pond) and thereby provide a quantitative measure of effort and success for an "in progress" reintroduction of toads. Our data also suggest that tadpoles released at later developmental stages have an increased probability of survival and that eggs laid in the wild hatched at higher rates than eggs laid by captive toads. We illustrate how an interim assessment can identify problems, highlight successes, and provide information for use in adjusting the effort or implementing a Decision-Theoretic adaptive management strategy.

  1. Comparative study on the tongue of Bufo regularis and Chalcides ocellatus in relation to their habitats

    Directory of Open Access Journals (Sweden)

    E.H. Elsheikh


    Full Text Available The present study investigated the structure of the tongue of the toad, Bufo regularis and the lizard, Chalcides ocellatus. They have different feeding habits and live in different habitats. The tongue of the toad contains two types of lingual papillae; fungiform papillae and filiform papillae. The fungiform papillae are usually scattered among the filiform papillae and are believed to function in gustation and in the secretion of salivary fluid. Scanning electron microscopical studies revealed that no ciliated cells were observed on the surface of the filiform papillae or in the surrounding area of the sensory disc. In C. ocellatus the tip of the tongue is bifurcated and keratinized. The dorsal surface of the tongue is covered with several types of papillae; irregular, scale and ridge-shaped. Taste buds were present in the epithelium of the tongue. The lingual glands consist of mucous cells that form crypt-like invaginations between papillae. The present study revealed that there is a marked correlation between the structure of the tongue of both B. regularis and C. ocellatus and habitats and feeding mechanism of the two species.

  2. Toxic effects of carbaryl on the histology of testes of Bufotes variabilis (Anura: Bufonidae

    Directory of Open Access Journals (Sweden)

    Ozlem Cakici


    Full Text Available This study was designed to investigate histopathologic effects of carbaryl on the testes of adult toad, Bufotes variabilis. To that end, animals were exposed to carbaryl once by oral gavage (low dose: 50 µg/g, medium dose: 100 µg/g and high dose: 200 µg/g. After 96 h, toads were euthanized. In low-dose group, some seminiferous tubules lost their regular shape. Also, the enlargement of interstitial spaces among tubules and germ cell necrosis were determined. A weak hemorrhage was observed among some tubules. In medium-dose group, germ cell necrosis was detected in many seminiferous tubules. This time, a weak hemorrhage was detected within tubules. In the high dose group, an increase in the number of disorganized tubules were observed. Vacuolization and necrosis in germ cells of seminiferous tubules were frequently seen. According to these findings, carbaryl caused dose-related histopathological damage in testis of B. variabilis. Based on these findings, this study clearly shows that carbaryl affects male fertility in B. variabilis.


    Energy Technology Data Exchange (ETDEWEB)

    Farfan, E.; Jannik, T.; Caldwell, E.


    In the most highly contaminated region of the Chernobyl Exclusion Zone: the 'Red Forest' site, the accumulation of the major dose-affecting radionuclides ({sup 90}Sr and {sup 137}Cs) within the components of an ecological system encompassing 3,000 m{sup 2} were characterized. The sampled components included soils (top 0-10 cm depth), Molina caerulea (blue moor grass), Camponotus vagus (carpenter ants) and Pelobates fuscus (spade-footed toad). In a comparison among the components of this ecosystem, the {sup 90}Sr and {sup 137}Cs concentrations measured in 40 separate grids exhibited significant differences, while the frequency distribution of the values were close to a logarithmically normal leptokurtic distribution with a significant right-side skew. While it is important to identify localized areas of high contamination or 'hot spots,' including these values in the arithmetic mean may overestimate the exposure risk. In component sample sets that exhibited logarithmically normal distribution, the geometrical mean more accurately characterizes a site. Ideally, risk assessment is most confidently achieved when the arithmetic and geometrical means are most similar, meaning the distribution approaches normal. Through bioaccumulation, the highest concentrations of {sup 90}Sr and {sup 137}Cs were measured in the blue moor grass and spade-footed toad. These components also possessed distribution parameters that shifted toward a normal distribution.

  4. Investigation of the effect of inositol trisphosphate in skinned skeletal muscle fibres with functional excitation-contraction coupling. (United States)

    Posterino, G S; Lamb, G D


    The effect of inositol trisphosphate (IP3) was investigated in mechanically skinned fibres which had the endogenous level of sarcoplasmic reticulum (SR) Ca2+ and in which the normal excitation-contraction (E-C) coupling mechanism was still functional. Application of 50 or 100 microM IP3 failed to induce a detectable force response in any such skinned fibre from either the extensor digitorum longus muscle of the rat or iliofibularis muscle of the toad, irrespective of whether the fibre was: (a) in its normally polarized, resting state; (b) chronically depolarized to inactivate the voltage sensors; (c) paralysed with D600; or (d) depolarized to threshold for force activation. Furthermore, the size of the response to subsequent depolarization or exposure to caffeine (2mM) or reduced myoplasmic [Mg2+] indicated that little if any Ca2+ had been lost from the SR during the period of IP3 exposure (> or = 1 min). Also, IP3 did not induce a detectable force response when SR Ca2+ uptake was potently inhibited with 20 microM TBQ. Exposure to IP3 (50 microM) slightly potentiated the peak force response to depolarization in toad fibres, and this was probably because of an accompanying small increase in Ca2+ sensitivity of the contractile apparatus. These results appear inconsistent with the proposal that IP3 acts as the second messenger in E-C coupling in skeletal muscle.

  5. Experimental evidence for beneficial effects of projected climate change on hibernating amphibians (United States)

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


    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. (United States)

    Reading, C J


    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. Reproduction, embryonic development, and maternal transfer of contaminants in the amphibian Gastrophryne carolinensis

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, W.A.; DuRant, S.E.; Staub, B.P.; Rowe, C.L.; Jackson, B.P. [Virginia Polytechnic Institute & State University, Blacksburg, VA (United States). Dept. of Fisheries & Wildlife Science


    Although many amphibian populations around the world are declining at alarming rates, the cause of most declines remains unknown. Environmental contamination is one of several factors implicated in declines and may have particularly important effects on sensitive developmental stages. We examined maternal transfer of contaminants in eastern narrow-mouth toads (Gastrophryne carolinensis) collected from a reference site and near a coal-burning power plant. Adult toads inhabiting the industrial area transferred significant quantities of selenium and strontium to their eggs, but Se concentrations were most notable (up to 100 {mu} g/g dry mass). Compared with the reference site, hatching success was reduced by 11% in clutches from the contaminated site. In surviving larvae, the frequency of developmental abnormalities and abnormal swimming was 55-58% higher in the contaminated site relative to the reference site. Craniofacial abnormalities were nearly an order of magnitude more prevalent in hatchlings from the contaminated site. When all developmental criteria were considered collectively, offspring from the contaminated site experienced 19% lower viability. Although there was no statistical relationship between the concentration of Se or Sr transferred to eggs and any measure of offspring viability, our study demonstrates that maternal transfer may be an important route of contaminant exposure in amphibians that has been overlooked.

  8. Multiple stressors in amphibian communities: Effects of chemical contamination, bullfrogs, and fish (United States)

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


    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.

  9. Sink or swim: a test of tadpole behavioral responses to predator cues and potential alarm pheromones from skin secretions. (United States)

    Maag, Nino; Gehrer, Lukas; Woodhams, Douglas C


    Chemical signaling is a vital mode of communication for most organisms, including larval amphibians. However, few studies have determined the identity or source of chemical compounds signaling amphibian defensive behaviors, in particular, whether alarm pheromones can be actively secreted from tadpoles signaling danger to conspecifics. Here we exposed tadpoles of the common toad Bufo bufo and common frog Rana temporaria to known cues signaling predation risk and to potential alarm pheromones. In both species, an immediate reduction in swimming activity extending over an hour was caused by chemical cues from the predator Aeshna cyanea (dragonfly larvae) that had been feeding on conspecific tadpoles. However, B. bufo tadpoles did not detectably alter their behavior upon exposure to potential alarm pheromones, neither to their own skin secretions, nor to the abundant predator-defense peptide bradykinin. Thus, chemicals signaling active predation had a stronger effect than general alarm secretions of other common toad tadpoles. This species may invest in a defensive strategy alternative to communication by alarm pheromones, given that Bufonidae are toxic to some predators and not known to produce defensive skin peptides. Comparative behavioral physiology of amphibian alarm responses may elucidate functional trade-offs in pheromone production and the evolution of chemical communication.

  10. The dual rod system of amphibians supports colour discrimination at the absolute visual threshold (United States)

    Yovanovich, Carola A. M.; Koskela, Sanna M.; Nevala, Noora; Kondrashev, Sergei L.


    The presence of two spectrally different kinds of rod photoreceptors in amphibians has been hypothesized to enable purely rod-based colour vision at very low light levels. The hypothesis has never been properly tested, so we performed three behavioural experiments at different light intensities with toads (Bufo) and frogs (Rana) to determine the thresholds for colour discrimination. The thresholds of toads were different in mate choice and prey-catching tasks, suggesting that the differential sensitivities of different spectral cone types as well as task-specific factors set limits for the use of colour in these behavioural contexts. In neither task was there any indication of rod-based colour discrimination. By contrast, frogs performing phototactic jumping were able to distinguish blue from green light down to the absolute visual threshold, where vision relies only on rod signals. The remarkable sensitivity of this mechanism comparing signals from the two spectrally different rod types approaches theoretical limits set by photon fluctuations and intrinsic noise. Together, the results indicate that different pathways are involved in processing colour cues depending on the ecological relevance of this information for each task. This article is part of the themed issue ‘Vision in dim light’. PMID:28193811

  11. All-optical prefix tree adder with the help of terahertz optical asymmetric demultiplexer

    Institute of Scientific and Technical Information of China (English)

    Dilip Kumar Gayen; Tanay Chattopadhyay; Rajat Kumar Pal; Jitendra Nath Roy


    We propose and describe an all-optical prefix tree adder with the help of a terahertz optical asymmetric demultiplexer (TOAD) using a set of optical switches. The prefix tree adder is useful in compound adder implementation. It is preferred over the ripple carry adder and the carry lookahead adder. We also describe the principle and possibilities of the all-optical prefix tree adder. The theoretical model is presented and verified through numerical simulation. The new method promises higher processing speed and accuracy. The model can be extended for studying more complex all-optical circuits of enhanced functionality in which the prefix tree adder is the basic building block.%@@ We propose and describe an all-optical prefix tree adder with the help of a terahertz optical asymmetric demultiplexer (TOAD) using a set of optical switches.The prefix tree adder is useful in compound adder implementation.It is preferred over the ripple carry adder and the carry lookahead adder.We also describe the principle and possibilities of the all-optical prefix tree adder.The theoretical model is presented and verified through numerical simulation.The new method promises higher processing speed and accuracy.The model can be extended for studying more complex all-optical circuits of enhanced functionality in which the prefix tree adder is the basic building block.

  12. Is “cooling then freezing” a humane way to kill amphibians and reptiles?

    Directory of Open Access Journals (Sweden)

    Richard Shine


    Full Text Available What is the most humane way to kill amphibians and small reptiles that are used in research? Historically, such animals were often killed by cooling followed by freezing, but this method was outlawed by ethics committees because of concerns that ice-crystals may form in peripheral tissues while the animal is still conscious, putatively causing intense pain. This argument relies on assumptions about the capacity of such animals to feel pain, the thermal thresholds for tissue freezing, the temperature-dependence of nerve-impulse transmission and brain activity, and the magnitude of thermal differentials within the bodies of rapidly-cooling animals. A review of published studies casts doubt on those assumptions, and our laboratory experiments on cane toads (Rhinella marina show that brain activity declines smoothly during freezing, with no indication of pain perception. Thus, cooling followed by freezing can offer a humane method of killing cane toads, and may be widely applicable to other ectotherms (especially, small species that are rarely active at low body temperatures. More generally, many animal-ethics regulations have little empirical basis, and research on this topic is urgently required in order to reduce animal suffering.

  13. 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.

  14. Frequency distributions of 90Sr and 137Cs concentrations in an ecosystem of the "Red Forest" area in the Chernobyl exclusion zone. (United States)

    Gaschak, Sergey P; Makliuk, Yulia A; Maksimenko, Andrey M; Bondarkov, Mikhail D; Chizhevsky, Igor; Caldwell, Eric F; Jannik, G Timothy; Farfán, Eduardo B


    In the most highly contaminated region of the Chernobyl Exclusion Zone, the "Red Forest" site, the accumulation of the major dose-affecting radionuclides (90Sr and 137Cs) within the components of an ecological system encompassing 3,000 m(2) was characterized. The sampled components included soils (top 0-10 cm depth), Molina caerulea (blue moor grass), Camponotus vagus (carpenter ants), and Pelobates fuscus (spade-footed toad). In a comparison among the components of this ecosystem, the 90Sr and 137Cs concentrations measured in 40 separate grids exhibited significant differences, while the frequency distribution of the values was close to a logarithmically-normal leptokurtic distribution with a significant right-side skew. While it is important to identify localized areas of high contamination or "hot spots," including these values in the arithmetic mean may overestimate the exposure risk. In component sample sets that exhibited logarithmically normal distribution, the geometric mean more accurately characterizes a site. Ideally, risk assessment is most confidently achieved when the arithmetic and geometric means are most similar, meaning the distribution approaches normal. Through bioaccumulation, the highest concentrations of 90Sr and 137Cs were measured in the blue moor grass and spade-footed toad. These components also possessed distribution parameters that shifted toward a normal distribution.

  15. Amphibian breeding and climate change: The importance of snow in the mountains (United States)

    Corn, P. Stephen


    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.

  16. Biological response to climate change on a tropical mountain (United States)

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


    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,.

  17. Experimental evidence for beneficial effects of projected climate change on hibernating amphibians. (United States)

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


    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.

  18. Predation of Ladybird Beetles (Coleoptera: Coccinellidae by Amphibians

    Directory of Open Access Journals (Sweden)

    John J. Sloggett


    Full Text Available Studies of predation of ladybird beetles (Coccinellidae have focused on a limited number of predator taxa, such as birds and ants, while other potential predators have received limited attention. I here consider amphibians as predators of ladybirds. Published amphibian gut analyses show that ladybirds are quite often eaten by frogs and toads (Anura, with recorded frequencies reaching up to 15% of dietary items. Salamanders (Caudata eat ladybirds less frequently, probably as their habits less often bring them into contact with the beetles. Amphibians do not appear to be deleteriously affected by the potentially toxic alkaloids that ladybirds possess. Amphibians, especially frogs and toads, use primarily prey movement as a release cue to attack their food; it is thus likely that their ability to discriminate against ladybirds and other chemically defended prey is limited. Because of this poor discriminatory power, amphibians have apparently evolved non-specific resistance to prey defensive chemicals, including ladybird alkaloids. Although amphibian-related ladybird mortality is limited, in certain habitats it could outweigh mortality from more frequently studied predators, notably birds. The gut analyses from the herpetological literature used in this study, suggest that in studying predation of insects, entomologists should consider specialized literature on other animal groups.

  19. Amphibian dynamics in constructed ponds on a wildlife refuge: developing expected responses to hydrological restoration (United States)

    Hossack, Blake R.


    Management actions are based upon predictable responses. To form expected responses to restoration actions, I estimated habitat relationships and trends (2002–2015) for four pond-breeding amphibians on a wildlife refuge (Montana, USA) where changes to restore historical hydrology to the system greatly expanded (≥8 times) the flooded area of the primary breeding site for western toads (Anaxyrus boreas). Additional restoration actions are planned for the near future, including removing ponds that provide amphibian habitat. Multi-season occupancy models based on data from 15 ponds sampled during 7 years revealed that the number of breeding subpopulations increased modestly for Columbia spotted frogs (Rana luteiventris) and was stationary for long-toed salamanders (Ambystoma macrodactylum) and Pacific treefrogs (Pseudacris regilla). For these three species, pond depth was the characteristic that was associated most frequently with occupancy or changes in colonization and extinction. In contrast, a large decrease in colonization by western toads explained the decline from eight occupied ponds in 2002 to two ponds in 2015. This decline occurred despite an increase in wetland area and the colonization of a newly created pond. These changes highlight the challenges of managing for multiple species and how management responses can be unpredictable, possibly reducing the efficacy of targeted actions.

  20. Toxicity of road salt to Nova Scotia amphibians

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Sara J. [Department of Biology, Saint Mary' s University, 923 Robie Street, Halifax, NS, B3H 3C3 (Canada); Russell, Ronald W. [Department of Biology, Saint Mary' s University, 923 Robie Street, Halifax, NS, B3H 3C3 (Canada)], E-mail:


    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 (LC{sub 50}) 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.

  1. Unique and shared responses of the gut microbiota to prolonged fasting: a comparative study across five classes of vertebrate hosts. (United States)

    Kohl, Kevin D; Amaya, James; Passement, Celeste A; Dearing, M Denise; McCue, Marshall D


    Many animals face unpredictable food sources and periods of prolonged fasting, which likely present significant challenges to gut microorganisms. While several studies have demonstrated that fasting impacts the gut microbiota, experiments have not been carried out in a comparative context. We used 16S rRNA gene sequencing to document changes in colonic and cecal microbiomes of animals representing five classes of vertebrates at four time points through prolonged fasting: tilapia, toads, geckos, quail, and mice. We found differences in the starvation-induced changes in the microbiome across host species and across gut regions. Microbial phylogenetic diversity increased as a result of fasting in the colons of fish, toads, and mice, while quail exhibited a decrease in diversity; geckos exhibited no change. Microbial diversity in the cecum decreased in fish and exhibited no change in mice. Alterations in relative abundances of microbial taxa varied across hosts. Fish exhibited the most significant changes due to fasting, while geckos maintained a stable community over 28 days of fasting. We uncovered several shared responses of the microbiota across hosts. For example, all tetrapods exhibited decreases in the abundances of Coprobacillus and Ruminococcus in response to fasting. We also discuss host-mediated physiological mechanisms that may underlie these community changes.

  2. From uni- to multimodality: towards an integrative view on anuran communication. (United States)

    Starnberger, Iris; Preininger, Doris; Hödl, Walter


    Undeniably, acoustic signals are the predominant mode of communication in frogs and toads. Acoustically active species are found throughout the vast diversity of anuran families. However, additional or alternative signal modalities have gained increasing attention. In several anurans, seismic, visual and chemical communications have convergently evolved due to ecological constraints such as noisy environments. The production of a visual cue, like the inevitably moving vocal sac of acoustically advertising males, is emphasized by conspicuously coloured throats. Limb movements accompanied by dynamic displays of bright colours are additional examples of striking visual signals independent of vocalizations. In some multimodal anuran communication systems, the acoustic component acts as an alert signal, which alters the receiver attention to the following visual display. Recent findings of colourful glands on vocal sacs, producing volatile species-specific scent bouquets suggest the possibility of integration of acoustic, visual and chemical cues in species recognition and mate choice. The combination of signal components facilitates a broadened display repertoire in challenging environmental conditions. Thus, the complexity of the communication systems of frogs and toads may have been underestimated.

  3. Gratkorn - A new late Middle Miocene vertebrate fauna from Styria (Late Sarmatian, Austria) (United States)

    Gross, M.; Böhme, M.; Prieto, J.


    Integrated stratigraphic approaches provide precise correlations of global standard stages with regional Paratethys stages. Nevertheless, higher resolution stratigraphic matching of terrestrial deposits remains challenging due to the lack of a practical continental biostratigraphy. The mostly used tool for biostratigraphic correlation of non-marine deposits in the Old World is still the concept of Neogene Mammal-zones (MN-zones). However, at higher biostratigraphic resolution (squirrels, gymnures and shrews are concentrated, perhaps demonstrating feeding places of carnivores or more probably of birds of prey. Nonetheless, from geologic point of view, this paleosol represents an event horizon, which accumulated rapidly maybe within tens or hundreds of years. The vertebrate fauna comprises of scattered fishes (e.g. cyprinids, gobiids, ?channids), amphibians (e.g. salamandrids, ranids, discoglossids, bufonids, pelobatids,), reptiles (scincids, lacertids, gekkonids, anguids, varanids, colubrids, testudinids, emydids), birds (coliiformes), rodents and lagomorphs (cricetids, glirids, eomyids, sciurids, castorids), insectivores and chiropterans (erinaceids, soricids, talpids), and large mammals (suids, tragulids, moschids, cervids, ?palaeomerycids, equids, chalicotheriids, rhinos, proboscidians, carnivors). Litho- and biostratigraphy (terrestrial gastropods) as well as magnetostratigraphic data and the sequence stratigraphic and geodynamic frame indicate an age of 12-12.2 Ma (early Late Sarmatian s.str., chron 5An.1n) for the locality. Therefore, Gratkorn is one of richest and most complete fauna of the late Middle Miocene of Central Europe and will be confidentially one of the key faunas for a high-resolution continental biostratigraphy and the comprehension of the faunal succession and interchanges near the Middle/Late Miocene transition. Acknowledgements This is a preliminary overview of the Gratkorn vertebrate fauna. Several taxa are still under investigation. We are

  4. FrogwatchUSA (United States)

    Droege, S.


    full text: Frogs and toads are perhaps the most approachable and available of all our wildlife. In many, if not most places, they are abundant. In wetter parts of the East, almost anyone outside on a warm rainy night in spring will hear their dream-like calls, bellows, trills and snores. Even in the deserts of the Southwest, a nocturnal trip after a summer monsoon will yield toads moving across the roads toward a cacophonous orgy of mating and calling in the roadside ditches and desert pools. Birds share with frogs and toads this same sense of presence in our daily lives. But the difference is that birds are like the attractive neighbor who just never gives you the time of day, while frogs are more like the troglodyte who appears regularly to chat, philosophize, and have a beer. Uninvited, frogs appear in our water gardens, toads are on our stoops in the morning, we catch them when we are kids, raise their babies in the aquarium, and feel sorry when we find we have run them over with the lawnmower. When concerns about declining populations of amphibians reached the mass media, the Secretaries' office became involved. In addition to using traditional research mechanisms to investigate the problem, the Secretary also wanted to involve the public directly. The combination of high public appeal and the relative ease with which frog calls can be learned made a large-scale monitoring program for frogs and toads possible. What emerged was a program called Frogwatch USA, modeled after a successful Canadian program with a similar name. A web site was created ( that presented potential frogwatchers with directions and a way to register their site online as well as enter their data. Observers chose where to count frogs depending on what they felt was important. For some it was their backyard, others chose vulnerable wetlands in their neighborhoods, or spots on local refuges and parks. Initially funded at $8,000 a year and then after two years increased to

  5. Effect of Angelica sinensis on toad’ s heart activities%当归对蛙心脏活动的影响

    Institute of Scientific and Technical Information of China (English)

    施晓楠; 杜瑞卿; 马亚静; 夏敏; 宋晓芳; 韩文星


    The aim of this study was to study the effect of Angelica sinennsis on toad heart activates. Using toad as experiment animal, we tested the heart rate, maximal cardiac contractility, mean cardiac contractility, and cardiac electric by BL-410 biological functional system in each four groups. Results showed that sinennsis had no effect on toad heart rate, but had obvious inhibition on maximal cardiac contractility, mean cardiac contractili-ty and cardiac electric. The index was increased first and then decreased with the increase amount of Angelica tablets. There was a significant positive correlation between cardiac contractility and cardiac electric. Based on the results, our conclusion was as follows:the kind of traditional Chinese medicine has no obvious effect on heart rate. However, it had effect on cardiac contractility and cardiac electric. With appropriate amount, it can protect heart from the myocardial ischemia, heart failure, etc.%为了研究当归对蟾蜍在体心脏活动功能的影响,以蟾蜍为实验动物,利用BL-410生物机能实验系统,以蟾蜍心率、心搏最大收缩力、心搏平均收缩力和心肌电为指标,该药分设四个实验组进行实验。结果表明:当归片对蟾蜍心率没有显著影响,对蟾蜍心搏最大收缩力、心搏平均收缩力和心肌电产生显著影响,随当归片灌胃量的增加,先增大后减小。心搏收缩力与心肌电表现出显著的正相关性。由此获得基本结论:当归对心率基本无显著影响,但对心脏的收缩力和心肌电有影响,适当的用量有利于改善心肌功能,在心肌缺血损伤、心力衰竭情况下,有利于保护心脏。

  6. Risks to Colombian amphibian fauna from cultivation of coca (Erythroxylum coca): a geographical analysis. (United States)

    Lynch, J D; Arroyo, S B


    The Colombian amphibian fauna is among the richest known in the world, with about 20 species of salamanders (order Caudata), 35 of the limbless caecilians (order Gymnophiona), and more than 700 species of frogs and toads (order Anura) recorded from localities within the country. The potential effects of exposure to glyphosate on amphibians arising from production of illegal crops (coca) were examined. The analysis was based on (1) behavior and ecology of species and (2) proximities of actual museum records to localities in which illegal crops are being grown and the subset of those that have been sprayed with glyphosate. Based on data on the location of amphibians collected in Colombia, records were obtained for 193 species (28% of the national diversity) of frogs and toads found in localities within 10 km of areas where coca is grown. Further analyses with ARC MAP software allowed for measurement of the direct distance separating collection locations for frogs, known coca fields, and areas where aerial spraying was being conducted. Records in or near coca fields included data for 11 of 13 families of frogs and toads known to be present in Colombia. Only Ceratophryidae and Pipidae were not reported from these locations and appear not to be at risk. For eight species (Dendrobates truncatus, Craugastor raniformis, Pristimantis gaigeae, Smilisca phaeota, Elachistocleis ovale, Hypsiboas crepitans, Trachycephalus venulosus, and Pseudis paradoxa) selected to represent several habitat preferences and life-cycle strategies, large areas of their distributions lie outside coca production regions and their populations as a whole are at low risk. For a limited number of species that barely enter Colombian territory, the consequences of coca production may be more serious and may have placed several species of frogs at risk. These include Ameerega bilingua, Dendropsophus bifurcus, Pristimantis colomai, P. degener, P. diadematus, P. quaquaversus, P. variabilis, and

  7. Structure of the novel membrane-coating material in proton-secreting epithelial cells and identification as an H+ATPase. (United States)

    Brown, D; Gluck, S; Hartwig, J


    Specialized proton-secreting cells known collectively as mitochondria-rich cells are found in a variety of transporting epithelia, including the kidney collecting duct (intercalated cells) and toad and turtle urinary bladders. These cells contain a population of characteristic tubulovesicles that are believed to be involved in the shuttling of proton pumps (H+ATPase) to and from the plasma membrane. These transporting vesicles have a dense, studlike material coating the cytoplasmic face of their limiting membranes and similar studs are also found beneath parts of the plasma membrane. We have recently shown that this membrane coat does not contain clathrin. The present study was performed to determine the structure of this coat in rapidly frozen and freeze-dried tissue, and to determine whether the coat contains a major membrane protein transported by these vesicles, a proton pumping H+ATPase. The structure of the coat was examined in proton-secreting, mitochondria-rich cells from toad urinary bladder epithelium by rapidly freezing portions of apical membrane and associated cytoplasm that were sheared away from the remainder of the cell using polylysine-coated coverslips. Regions of the underside of these apical membranes as large as 0.2 micron2 were decorated by studlike projections that were arranged into regular hexagonal arrays. Individual studs had a diameter of 9.5 nm and appeared to be composed of multiple subunits arranged around a central depression, possibly representing a channel. The studs had a density of approximately 16,800 per micron2 of membrane. Similar arrays of studs were also found on vesicles trapped in the residual band of cytoplasm that remained attached to the underside of the plasma membrane, but none were seen in adjacent granular cells. To determine whether these arrays of studs contained H+ATPase molecules, we examined a preparation of affinity-purified bovine medullary H+ATPase, using the same technique, after incorporation of the

  8. Dosagem de marcadores cardíacos CK-MB e TnIc e eletrólitos no envenenamento experimental por veneno de sapo em cães

    Directory of Open Access Journals (Sweden)

    Annelise C. Camplesi


    Full Text Available Dentre os sinais sistêmicos causados pelo envenenamento por veneno de sapo (bufotoxina em cães, os efeitos cardiotóxicos são um dos mais importantes. O objetivo deste estudo foi avaliar as potenciais alterações no músculo cardíaco de cães envenenados experimentalmente por veneno de sapo e observar as alterações eletrolíticas que podem ocorrer nesse tipo de envenenamento. Utilizaram-se 20 cães divididos em grupo controle (n=5 e grupo envenenado (n=15. O veneno de sapo foi extraído por meio de compressão manual das glândulas paratóides. Após anestesia geral, os cães do grupo controle receberam placebo (solução fisiológica e os do grupo envenenado uma alíquota do veneno por sonda orogástrica. As colheitas de sangue para dosagem dos marcadores cardíacos foram realizadas seis e 24 horas após o envenenamento. As colheitas de sangue para dosagem dos eletrólitos foram realizadas antes e duas, quatro, seis e 12 horas após o envenenamento. A análise estatística empregada foi o teste não-paramétrico de Mann-Withney (PAmong the systemic signs of toad venom (bufotoxin poisoning in dogs, the cardiotoxic effects are one of the most important. Thus, the objective of this experiment was to evaluate potential changes in the cardiac muscle in dogs poisoned experimentally by toad venom and to observe the eletrolyte alterations which may occur in this condition. Twenty dogs divided into control group (n=5 and poisoned group (n=15 were utilized. The toad venom was extracted by manual compression of the paratoidic glands. After general anesthesia, dogs in the control group received placebo and dogs in the poisoned group received the venom by orogastric catheter. Samples for dosage were collected 6 hours and 24 hours after poisoning and 0, 2, 4, 6 and 12 hours after poisoning for electrolytes dosage. The Man-Withney test was used for statistical analysis (P<0.05. The poisoned dogs showed (saline elevated levels of cardiac markers CK

  9. Influenza em animais heterotérmicos Influenza in heterothermics

    Directory of Open Access Journals (Sweden)

    Dalva Assunção Portari Mancini


    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

  10. Lectin histochemistry shows the comparative biosynthesis and cellular biodistribution of alpha L-fucose residues in some tissues of tetrapoda representatives. (United States)

    Awaad, Aziz


    Fucose is a monosaccharide that plays several immunological roles. This study investigated the comparative biosynthesis and cellular biodistribution of fucose residues in some tissues of tetrapoda representatives using lectin histochemistry. In this study, the mouse was used as a representative for mammalian, pigeon for avian, lizard for reptilian, and toad for amphibians. The localization of the fucose residues was seen in several cell types of mice ileum, such as villi microfold (M) cells, goblet cells, some of intestinal crypts cells, and lamina propria cells. In other tetrapoda representatives, fucose was only seen in M cells of lizard ileum and some cells of villi lamina propria of pigeon, lizard, and toad. It was also observed in the pancreatic acinar cells of the mouse and some cell aggregations of pancreatic parenchyma of the lizard. Contrarily, it was not seen either in pigeon or in toad pancreases parenchyma. Spleen of all animals showed the fucose residues in some splenic cells in the red pulp only, barring the white pulp. The liver parenchyma of all tetrapoda representatives hadn't fucose residues. The fucose cellular biodistribution in some cells of tetrapoda representatives differed based on the cell type. In the mouse, it was highly seen in the apical cytoplasm of the villi M cells as well as in the cup-like part of goblet cells. In addition, it was seen as "rings" in the granule membranes of the Ulex europeaus agglutinin I (UEAI(+)) cells in the intestinal crypts cells. Furthermore, the UEAI(+) cells in the lamina propria showed fucose granules in their cytoplasm. There is no clear evidence about the relation between the cellular biosynthesis of fucose residues and mucosal immune cells. The role of fucose residues in the pancreatic acinar cells are not well understood and need further investigations. In this study, fucose residues were synthesized in several types of cells in the mouse ileum, spleen and pancreas as compared with other tetrapoda. The

  11. Liver-targeting Resibufogenin-loaded poly(lactic-co-glycolic acid-D-α-tocopheryl polyethylene glycol 1000 succinate nanoparticles for liver cancer therapy

    Directory of Open Access Journals (Sweden)

    Chu QC


    Full Text Available Qiuchen Chu,1,* Hong Xu,2,* Meng Gao,1 Xin Guan,1 Hongyan Liu,1 Sa Deng,1 Xiaokui Huo,1 Kexin Liu,1 Yan Tian,1 Xiaochi Ma1 1College of Pharmacy, 2College of Basic Medical Sciences, Dalian Medical University, Dalian, People’s Republic of China *These authors contributed equally to this work Abstract: Liver cancer remains a major problem around the world. Resibufogenin (RBG is a major bioactive compound that was isolated from Chansu (also called toad venom or toad poison, which is a popular traditional Chinese medicine that is obtained from the skin secretions of giant toads. RBG has strong antitumor effects, but its poor aqueous solubility and its cardiotoxicity have limited its clinical use. The aim of this study was to formulate RBG-loaded poly(lactic-co-glycolic acid (PLGA-D-α-tocopheryl polyethylene glycol 1000 succinate nanoparticle (RPTN to enhance the treatment of liver cancer. RPTN, RBG-loaded PLGA nanoparticle (RPN, and RBG/coumarin-6-loaded PLGA-D-α-tocopheryl polyethylene glycol 1000 succinate nanoparticle (RCPTN were prepared. The cellular uptake of RCPTN by HepG2 and HCa-F cells was analyzed using confocal laser scanning microscopy. Apoptosis was induced in HepG2 cells by RPTN, RBG solution (RS, and 5-fluorouracil solution (used as the negative controls, as assayed using flow cytometry. LD50 (median lethal dose values were determined for RS and RPTN, and the liver-targeting properties were determined for RCPTN in intravenously injected mice. A pharmacokinetic study was conducted in rats, and the in vivo therapeutic effects of RPTN, RPN, and RS were examined in a mouse tumor model. The results showed that RCPTN simultaneously delivered both coumarin-6 and RBG into HepG2 and HCa-F cells. The ratio of apoptotic cells was increased in the RPTN group. The LD50 for RPTN was 2.02-fold higher than the value for RS. Compared to RS, RPTN and RPN both showed a significant difference in vivo not only in the pharmacodynamic study but also in

  12. Liver-targeting Resibufogenin-loaded poly(lactic-co-glycolic acid)-d-α-tocopheryl polyethylene glycol 1000 succinate nanoparticles for liver cancer therapy (United States)

    Chu, Qiuchen; Xu, Hong; Gao, Meng; Guan, Xin; Liu, Hongyan; Deng, Sa; Huo, Xiaokui; Liu, Kexin; Tian, Yan; Ma, Xiaochi


    Liver cancer remains a major problem around the world. Resibufogenin (RBG) is a major bioactive compound that was isolated from Chansu (also called toad venom or toad poison), which is a popular traditional Chinese medicine that is obtained from the skin secretions of giant toads. RBG has strong antitumor effects, but its poor aqueous solubility and its cardiotoxicity have limited its clinical use. The aim of this study was to formulate RBG-loaded poly(lactic-co-glycolic acid) (PLGA)-d-α-tocopheryl polyethylene glycol 1000 succinate nanoparticle (RPTN) to enhance the treatment of liver cancer. RPTN, RBG-loaded PLGA nanoparticle (RPN), and RBG/coumarin-6-loaded PLGA-d-α-tocopheryl polyethylene glycol 1000 succinate nanoparticle (RCPTN) were prepared. The cellular uptake of RCPTN by HepG2 and HCa-F cells was analyzed using confocal laser scanning microscopy. Apoptosis was induced in HepG2 cells by RPTN, RBG solution (RS), and 5-fluorouracil solution (used as the negative controls), as assayed using flow cytometry. LD50 (median lethal dose) values were determined for RS and RPTN, and the liver-targeting properties were determined for RCPTN in intravenously injected mice. A pharmacokinetic study was conducted in rats, and the in vivo therapeutic effects of RPTN, RPN, and RS were examined in a mouse tumor model. The results showed that RCPTN simultaneously delivered both coumarin-6 and RBG into HepG2 and HCa-F cells. The ratio of apoptotic cells was increased in the RPTN group. The LD50 for RPTN was 2.02-fold higher than the value for RS. Compared to RS, RPTN and RPN both showed a significant difference in vivo not only in the pharmacodynamic study but also in anticancer efficacy, and RPTN performed much better than RPN. The detection indexes for drug concentration and fluorescence inversion microscopy images both demonstrated that RCPTN was much better at targeting the liver than RS. The liver-targeting RPTN, which displayed enhanced pharmacological effects and

  13. Adaptation or exaptation? An experimental test of hypotheses on the origin of salinity tolerance in Bufo calamita. (United States)

    Gomez-Mestre, I; Tejedo, M


    The natterjack toad (Bufo calamita) shows variation in embryonic and larval salinity tolerance across populations in southern Spain. However, its aquatic/terrestrial biphasic life cycle, together with remarkable differences in salinity tolerance between Spanish and UK freshwater populations suggest an alternative hypothesis to local adaptation. Drought resistance during the terrestrial phase and salinity tolerance during the aquatic phase are both related to osmotic stress tolerance, and if there were an association between them, one could have evolved as an exaptation from the other. To test such an association, we reared B. calamita juveniles from three populations known to differ genetically in their salinity tolerance, under either dry or humid conditions. Drought decreased growth rate, enhanced burying behaviour, and decreased foraging activity and efficiency. No significant population x treatment interaction was found for any variable, i.e. populations were equally affected by drought. These results do not support the hypothesis of a genetic association between salinity and drought tolerance.

  14. All-optical clock recovery from 10-Gb/s NRZ data and NRZ to RZ format conversion

    Institute of Scientific and Technical Information of China (English)

    Lina Yin; Yumei Yan; Yunfeng Zhou; Jian Wu; Jintong Lin


    A non-return-to-zero (NRZ) to pseudo-return-to-zero (PRZ) converter consisting of a semiconductor optical amplifier (SOA) and an arrayed waveguide grating (AWG) is proposed, by which the enhancement of clock frequency component and clock-to-data suppression ratio of the NRZ data are evidently achieved. Alloptical clock recovery from NRZ data at 10 Gb/s is successfully demonstrated with the proposed NRZ-to-PRZ converter and a mode-locked SOA fiber laser. Furthermore, NRZ-to-RZ format conversion of 10 Gb/s is realized by using the recovered clock as the control light of terahertz optical asymmetric demultiplexer(TOAD), which further proves that the proposed clock recovery scheme is applicable.

  15. Conservation needs of amphibians in China:A review

    Institute of Scientific and Technical Information of China (English)

    Michael; Wai; Neng; LAU; Simon; N; STUART; Janice; S; CHANSON; Neil; A; COX; Debra; L; FISCHMAN


    The conservation status of all the amphibians in China is analyzed,and the country is shown to be a global priority for conservation in comparison to many other countries of the world.Three Chinese regions are particularly rich in amphibian diversity:Hengduan,Nanling,and Wuyi mountains.Sala-manders are more threatened than frogs and toads.Several smaller families show a high propensity to become seriously threatened:Bombinatoridae,Cryptobranchidae,Hynobiidae and Salamandridae.Like other parts of the world,stream-breeding,high-elevation forest amphibians have a much higher likeli-hood of being seriously threatened.Habitat loss,pollution,and over-harvesting are the most serious threats to Chinese amphibians.Over-harvesting is a less pervasive threat than habitat loss,but it is more likely to drive a species into rapid decline.Five conservation challenges are mentioned with recommendations for the highest priority research and conservation actions.

  16. Phenomenological models of the dynamics of muscle during isotonic shortening. (United States)

    Yeo, Sang Hoon; Monroy, Jenna A; Lappin, A Kristopher; Nishikawa, Kiisa C; Pai, Dinesh K


    We investigated the effectiveness of simple, Hill-type, phenomenological models of the force-length-velocity relationship for simulating measured length trajectories during muscle shortening, and, if so, what forms of the model are most useful. Using isotonic shortening data from mouse soleus and toad depressor mandibulae muscles, we showed that Hill-type models can indeed simulate the shortening trajectories with sufficiently good accuracy. However, we found that the standard form of the Hill-type muscle model, called the force-scaling model, is not a satisfactory choice. Instead, the results support the use of less frequently used models, the f-max scaling model and force-scaling with parallel spring, to simulate the shortening dynamics of muscle.

  17. User’s Guide for SAMUEL, Version 1.3. (United States)


    t .itt to 4.etaqt 1 thO , Ott .e’WOs.e .ntcuonq th re tote 0 fe..tewtr3 g lsttr ,Oo, le.*t(oo. e.’t~n Cat . toottel g.theeoq s.,h toad the da(A neded...82170 cOdetl. so te-e. t~t ,oIe.Ot 0t tflOlt*.t ten CO tt t dog Itis b-t1d, litotato 0, *Or OI Pe C o Qt tO,tO~leotot0 Ot Lt O ,t .od’oq soqqei~t~On...on the notion of competition and employs genetic algorithms to search the space of decision policies. The rule language in SAMUEL also makes it easier

  18. Impact of otter (Lutra lutra predation on amphibians in temporary ponds in Southern Spain

    Directory of Open Access Journals (Sweden)

    Dan Cogălniceanu


    Full Text Available We report the observation of an event of mortality of ribbed newts (Pleurodeles waltl and Iberian spadefoot toads (Pelobates cultripes due to predation by a pair of otters (Lutra lutra in a temporary pond complex in southern Spain. The peculiar predation mode on ribbed newts, with extraction of soft organs through an incision in the upper part of the thorax, may result in an under estimate of the importance of this species in the diet of otters. The high number of dead amphibians killed by two otters in only several hours suggests that the presence of these predators may pose a serious threat to amphibian populations. The risk is especially high in arid areas, with few ponds, synchronous reproductive migration, and high density of animals. We consider that measures promoting the conservation and population and range increase of otters might have a negative impact on amphibians.

  19. Populations of a susceptible amphibian species can grow despite the presence of a pathogenic chytrid fungus.

    Directory of Open Access Journals (Sweden)

    Ursina Tobler

    Full Text Available Disease can be an important driver of host population dynamics and epizootics can cause severe host population declines. Batrachochytrium dendrobatidis (Bd, the pathogen causing amphibian chytridiomycosis, may occur epizootically or enzootically and can harm amphibian populations in many ways. While effects of Bd epizootics are well documented, the effects of enzootic Bd have rarely been described. We used a state-space model that accounts for observation error to test whether population trends of a species highly susceptible to Bd, the midwife toad Alytes obstetricans, are negatively affected by the enzootic presence of the pathogen. Unexpectedly, Bd had no negative effect on population growth rates from 2002-2008. This suggests that negative effects of disease on individuals do not necessarily translate into negative effects at the population level. Populations of amphibian species that are susceptible to the emerging disease chytridiomycosis can persist despite the enzootic presence of the pathogen under current environmental conditions.

  20. Effects of chlorobutanol and bradykinin on myocardial excitation. (United States)

    Hermsmeyer, K; Aprigliano, O


    The negative inotropic effect of a commonly used formulation of bradykinin (Sandoz BRS-640) was found to be due to chlorobutanol, a constituent of the preparation. Solutions containing up to 100 mug of crystalline bradykinin/ml had no effect on tension or action-potential shape. Chlorobutanol (500 mug/ml) caused a 30% decrease in contraction amplitude and a 20% increase in action-potential duration. Chlorobutanol lowered conduction velocity and induced conduction failure and automaticity within isolated ventricular muscle strips. Chlorobutanol affected neither positive nor negative treppe. We conclude that bradykinin has no direct action on toad, frog, or rat myocardium. However, chlorobutanol does have direct effects on myocardial cells, acting on the cell membrane and decreasing isometric tension produced by the heart.

  1. Quantifying Demyelination in NK venom treated nerve using its electric circuit model (United States)

    Das, H. K.; Das, D.; Doley, R.; Sahu, P. P.


    Reduction of myelin in peripheral nerve causes critical demyelinating diseases such as chronic inflammatory demyelinating polyneuropathy, Guillain-Barre syndrome, etc. Clinical monitoring of these diseases requires rapid and non-invasive quantification of demyelination. Here we have developed formulation of nerve conduction velocity (NCV) in terms of demyelination considering electric circuit model of a nerve having bundle of axons for its quantification from NCV measurements. This approach has been validated and demonstrated with toad nerve model treated with crude Naja kaouthia (NK) venom and also shows the effect of Phospholipase A2 and three finger neurotoxin from NK-venom on peripheral nerve. This opens future scope for non-invasive clinical measurement of demyelination.

  2. Body Surface Area Prediction in Odorrana grahami

    Institute of Scientific and Technical Information of China (English)

    Guiying CHEN; Jiongyu LIU; Qiang DAI; Jianping JIANG


    Body surface area (BSA) was regarded as a more readily quantiifable parameter relative to body mass in the normalization of comparative biochemistry and physiology. The BSA prediction has attracted unceasing research back more than a century on animals, especially on humans and rats. Few studies in this area for anurans were reported, and the equation for body surface area (S) and body mass (W):S=9.9 W 0.56, which was concluded from toads of four species in 1969, was generally adopted to estimate the body surface areas for anurans until recent years. However, this equation was not applicable to Odorrana grahami. The relationship between body surface area and body mass for this species was established as:S=15.4 W 0.579. Our current results suggest estimation equations should be used cautiously across different species and body surface area predictions on more species need to be conducted.

  3. 三王止痛膏治疗癌性疼痛60例疗效观察%Observation on therapeutic effect of Sanwang pain alleviating plaster on cancerous pain in 60 cases

    Institute of Scientific and Technical Information of China (English)

    潘敏求; 黎月恒; 蒋益兰; 吴玉华; 苏旭春


    Objective To observe the therapeutic effect of Sanwang pain alleviating plaster on cancerous pain.Method The study was a randomized,single blinded trial.The patients were randomly divided into 2 groups,study group and control group.Control group received toad plaster.Pain level,functions time and duration of sanwang pain alleviating plaster,quality of life,peripheral blood picture,liver and kidney function,EEG,local stimulation and allergy of skin were evaluated before and after treatment.Result For the study group,total effective rate,duration,KS improvement rate were significantly raised as compared with control group.Total effective rate was different between two groups(P< 0.05) .Conclusion Sanwang pain alleviating plaster can effectively control cancerous pain and improve quality of life.

  4. Effects of the local anesthetic benzocaine on the human erythrocyte membrane and molecular models. (United States)

    Suwalsky, Mario; Schneider, Carlos; Villena, Fernando; Norris, Beryl; Cárdenas, Hernán; Cuevas, Francisco; Sotomayor, Carlos P


    The interaction of the local anesthetic benzocaine with the human erythrocyte membrane and molecular models is described. The latter consisted of isolated unsealed human erythrocyte membranes (IUM), large unilamellar vesicles (LUV) of dimyristoylphospatidylcholine (DMPC), and phospholipid multilayers of DMPC and dimyristoylphospatidyletanolamine (DMPE), representatives of phospholipid classes located in the outer and inner monolayers of the human erythrocyte membrane, respectively. Optical and scanning electron microscopy of human erythrocytes revealed that benzocaine induced the formation of echinocytes. Experiments performed on IUM and DMPC LUV by fluorescence spectroscopy showed that benzocaine interacted with the phospholipid bilayer polar groups and hydrophobic acyl chains. X-ray diffraction analysis of DMPC confirmed these results and showed that benzocaine had no effects on DMPE. The effect on sodium transport was also studied using the isolated toad skin. Electrophysiological measurements indicated a significant decrease in the potential difference (PD) and in the short-circuit current (Isc) after the application of benzocaine, reflecting inhibition of active ion transport.

  5. Book review: Amphibians and reptiles in Minnesota (United States)

    Mushet, David M.


    The photograph of a young boy poised to capture a wood frog (Lithobates sylvaticus) on page 3 of Amphibians and Reptiles in Minnesota captures perfectly the sense of awe and wonderment that one encounters throughout John Moriarty and Carol Hall’s new book. This is a spirit that most children possess naturally and that is so readily apparent when one of them comes face-to-face with one of the 53 species of frogs, toads, salamanders, turtles, lizards, or snakes that make Minnesota their home. This is a spirit that the authors have maintained in their hearts throughout almost 30 years of chasing, capturing, and studying amphibians and reptiles (a.k.a., herptiles or herps) in Minnesota. It is also the spirit that you will find reawakening in yourself as you turn from one page to the next and encounter the abundant color photos and descriptive text within this book.

  6. Invasive and introduced reptiles and amphibians: Chapter 28 (United States)

    Reed, Robert N.; Krysko, Kenneth L.; Mader, Douglas R.; Divers, Stephen J.


    Why is there a section on introduced amphibians and reptiles in this volume, and why should veterinarians care about this issue? Globally, invasive species are a major threat to the stability of native ecosystems,1,2 and amphibians and reptiles are attracting increased attention as potential invaders. Some introduced amphibians and reptiles have had a major impact (e.g., Brown Tree Snakes [Boiga irregularis] wiping out the native birds of Guam3 or Cane Toads [Rhinella marina] poisoning native Australian predators).4 For the vast majority of species, however, the ecological, economic, and sociopolitical effects of introduced amphibians and reptiles are generally poorly quantified, largely because of a lack of focused research effort rather than because such effects are nonexistent. This trend is alarming given that rates of introduction have increased exponentially in recent decades.

  7. Maternal investment influences expression of resource polymorphism in amphibians: implications for the evolution of novel resource-use phenotypes. (United States)

    Martin, Ryan A; Pfennig, David W


    Maternal effects--where an individual's phenotype is influenced by the phenotype or environment of its mother--are taxonomically and ecologically widespread. Yet, their role in the origin of novel, complex traits remains unclear. Here we investigate the role of maternal effects in influencing the induction of a novel resource-use phenotype. Spadefoot toad tadpoles, Spea multiplicata, often deviate from their normal development and produce a morphologically distinctive carnivore-morph phenotype, which specializes on anostracan fairy shrimp. We evaluated whether maternal investment influences expression of this novel phenotype. We found that larger females invested in larger eggs, which, in turn, produced larger tadpoles. Such larger tadpoles are better able to capture the shrimp that induce carnivores. By influencing the expression of novel resource-use phenotypes, maternal effects may play a largely underappreciated role in the origins of novelty.

  8. Maternal investment influences expression of resource polymorphism in amphibians: implications for the evolution of novel resource-use phenotypes.

    Directory of Open Access Journals (Sweden)

    Ryan A Martin

    Full Text Available Maternal effects--where an individual's phenotype is influenced by the phenotype or environment of its mother--are taxonomically and ecologically widespread. Yet, their role in the origin of novel, complex traits remains unclear. Here we investigate the role of maternal effects in influencing the induction of a novel resource-use phenotype. Spadefoot toad tadpoles, Spea multiplicata, often deviate from their normal development and produce a morphologically distinctive carnivore-morph phenotype, which specializes on anostracan fairy shrimp. We evaluated whether maternal investment influences expression of this novel phenotype. We found that larger females invested in larger eggs, which, in turn, produced larger tadpoles. Such larger tadpoles are better able to capture the shrimp that induce carnivores. By influencing the expression of novel resource-use phenotypes, maternal effects may play a largely underappreciated role in the origins of novelty.

  9. Amphibians of the Aurunci Mountains (Latium, Central Italy. Checklist and conservation guidelines

    Directory of Open Access Journals (Sweden)

    Antonio Romano


    Full Text Available The Aurunci Mounts are among the less investigated areas of Latium for herpetological researches. In this study we surveyed 72 potential breeding sites of amphibians within the Monti Aurunci Regional Park. Fifty-eight spawning sites, and nine amphibian species (64.3% out the 14 amphibian species living in Latium region have been found. Green toad and European tree frog were recorded for the first time for the Aurunci Mounts. Reproductive activity was recorded for Salamandrina perspicillata, Triturus carnifex, Lissotriton vulgaris, Lissotriton italicus, Bufo bufo, Pseudopidalea viridis, Hyla intermedia, Rana italica and Rana synklepton hispanica. Unexpectedly, no amphibian species has been recorded within the Monte Redentore (pSIC IT6040027, despite this site was included within the Natura 2000 network also basing on the presence of Triturus carnifex.

  10. A study of the relict fish fauna of northern Chad, with the first records of a polypterid and a poeciliid in the Sahara desert. (United States)

    Trape, Sébastien


    Seventeen species and sub-species of fishes belonging to four families (Cyprinidae, Clariidae, Aplocheilidae, Cichlidae) were known to occur in perennial bodies of water in the Sahara desert. The study of fishes collected in Lake Boukou near Ounianga Serir (Borkou, northern Chad) shows, for the first time, the occurrence in the Sahara desert of relict populations of Polypterus senegalus (Polypteridae) and Poropanchax normani (Poeciliidae). The Cichlidae Tilapia zilli was also collected in this lake. With these new records, the relict fish fauna currently known in lakes and gueltas of the Borkou plateaus comprises six species. In the Ennedi Mountains, where the specific status of Barbus populations was unclear, B. macrops was collected in Bachikere guelta. The toad Amietophrynus regularis was collected in Ounianga Kebir.

  11. 4MOST fiber feed concept design (United States)

    Haynes, D. M.; Winkler, R.; Saviauk, Allar; Haynes, R.; Barden, S.; Bellido-Tirado, O.; Bauer, S.; de Jong, Roelof S.; Depagne, E.; Dionies, F.; Ehrlich, K.; Kelz, Andreas; Saunders, W.; Woche, M.


    4MOST, the 4m Multi-Object Spectroscopic Telescope, features a 2.5 degree diameter field-of-view with ~2400 fibers in the focal plane that are configured by a fiber positioner based on the tilting spine principle (Echidna/FMOS) arranged in a hexagonal pattern. The fibers feed two types of spectrographs; ~1600 fibers go to two spectrographs with resolution R>5000 and ~800 fibers to a spectrograph with R>18,000. Part of the ongoing optimization of the fiber feed subsystem design includes early prototyping and testing of key components such as fiber connectors and fiber cable management. Performance data from this testing will be used in the 4MOST instrument simulator (TOAD) and 4MOST system design optimization. In this paper we give an overview of the current fiber feed subsystem design, simulations and prototyping plans.

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

    Purwaningsih, Endang; Dewi, Kartika; Hasegawa, Hideo


    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.

  13. Climate change promotes hybridisation between deeply divergent species (United States)

    Chiocchio, Andrea; Zampiglia, Mauro; Nascetti, Giuseppe


    Rare hybridisations between deeply divergent animal species have been reported for decades in a wide range of taxa, but have often remained unexplained, mainly considered chance events and reported as anecdotal. Here, we combine field observations with long-term data concerning natural hybridisations, climate, land-use, and field-validated species distribution models for two deeply divergent and naturally sympatric toad species in Europe (Bufo bufo and Bufotes viridis species groups). We show that climate warming and seasonal extreme temperatures are conspiring to set the scene for these maladaptive hybridisations, by differentially affecting life-history traits of both species. Our results identify and provide evidence of an ultimate cause for such events, and reveal that the potential influence of climate change on interspecific hybridisations goes far beyond closely related species. Furthermore, climate projections suggest that the chances for these events will steadily increase in the near future. PMID:28348926

  14. Conservation needs of amphibians in China: A review

    Institute of Scientific and Technical Information of China (English)

    XIE Feng; Michael Wai Neng LAU; Simon N STUART; Janice S CHANSON; Neil A COX; Debra L FISCHMAN


    The conservation status of all the amphibians in China is analyzed, and the country is shown to be a global priority for conservation in comparison to many other countries of the world. Three Chinese regions are particularly rich in amphibian diversity: Hengduan, Nanling, and Wuyi mountains. Salamanders are more threatened than frogs and toads. Several smaller families show a high propensity to become seriously threatened: Bombinatoridae, Cryptobranchidae, Hynobiidae and Salamandridae. Like other parts of the world, stream-breeding, high-elevation forest amphibians have a much higher likelihood of being seriously threatened. Habitat loss, pollution, and over-harvesting are the most serious threats to Chinese amphibians. Over-harvesting is a less pervasive threat than habitat loss, but it is more likely to drive a species into rapid decline. Five conservation challenges are mentioned with recommendations for the highest priority research and conservation actions.

  15. Venomous and poisonous Australian animals of veterinary importance: a rich source of novel therapeutics. (United States)

    Hardy, Margaret C; Cochrane, Jonathon; Allavena, Rachel E


    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. Despite the potency of Australian venoms, there is potential for novel veterinary therapeutics to be modeled on venom toxins, as has been the case with human pharmaceuticals. A comprehensive overview of envenomation and poisoning signs in livestock and companion animals is provided and related to the potential for venom toxins to act as therapeutics.

  16. Venomous and Poisonous Australian Animals of Veterinary Importance: A Rich Source of Novel Therapeutics

    Directory of Open Access Journals (Sweden)

    Margaret C. Hardy


    Full Text Available 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. Despite the potency of Australian venoms, there is potential for novel veterinary therapeutics to be modeled on venom toxins, as has been the case with human pharmaceuticals. A comprehensive overview of envenomation and poisoning signs in livestock and companion animals is provided and related to the potential for venom toxins to act as therapeutics.

  17. 基于电气信号传递特性的“经络”轨迹研究%Study on Display of Acupuncture Meridian Based on Electric Signal Transfer Characteristics

    Institute of Scientific and Technical Information of China (English)

    王志功; 吕晓迎; 王苏阳; 黄岑宇; 陈玥琳; 王一夫; 李艺辉


    目的:根据多端口网络理论和电信号传递系数测量方法,观察电针作用的实时电学效果,为客观确定体内“经络”轨迹及其生理特性摸索途径.方法:将机体模型化为一个“非均匀立体多端口网络”,“经络”定义为“信号传递最畅通道”.以脊蟾蜍为动物模型,在其前后肢制定等身寸坐标,利用一根加工成锥状的同心圆电极刺入实验动物体内,模拟电针治疗施加特设电压信号进行刺激,另一根同样的同心圆电极三维扫描式刺入体内不同位点进行探测.测出各点响应电压并求得电压信号传递系数值后,选取极值点作为“穴位”,将它们连线作为“经络”的轨迹.结果:在12只脊蟾蜍一侧前后肢皮内2 mm深度上下测出了12条由电信号传递函数极值点连接起来的三维曲线.结论:在蟾蜍体内初步验证了从电信号传递特性出发研究电针作用效果和“经络”轨迹的方法的可行性.%Objective To analyze the real-time effects of electroacupuncture (EA) stimulation by means of multiport network theory and measurement of the electric signals transfer coefficient,so as to explore a way for determining the running course of acupuncture meridian and for characterizing its physiological activities in the living body.Methods The body was modeled as a complex inhomogeneous 3-dimensions multi-port network,and the meridians were assumed to be "the most smoothly channels for signal transmission".Experiments were performed in 12 beheaded toads whose forelimbs and hindlimbs were divided into proportional coordinates.A concentric electrode with a conical tip was inserted into the toad leg for electrical stimulation of the local muscle,and another electrode alike was inserted into different spots of the limbs to detect the spreading signals in a 3-dimensional scanning mode.Following detecting the response electric voltage values of various spots and calculating their transfer

  18. Microelectronics-embedded channel bridging and signal regeneration of injured spinal cords

    Institute of Scientific and Technical Information of China (English)

    Zhigong Wang; Xiaosong Gu; Xiaoying Lü; Zhenglin Jiang; Wenyuan Li; Guangming Lü; Yufeng Wang; Xiaoyan Shen; Xintai Zhao; Huiling Wang; Zhenyu Zhang; Hongmei Shen; Yang Wu; Weixing Shen; Jingyang Zhang; Dong Chen; Xiaoyi Mao; Huaxiang Shen


    Due to the difficulty in spinal cord regeneration with biological methods, the microelectronic neural bridge, a new concept based on microelectronic technology, is presented. The microelectronic system has been realized in the forms of hybrid and integrated circuits. The integrated circuits for neural signal detection, stimulation, and regeneration are realized in a CMOS process. In animal experiments with 100 toads, 48 rats, and 3 rabbits, nerve signals have been successfully detected from spinal cords and sciatic nerves, and functional electrical stimulation has been carried out for spinal cords and sciatic nerves. When the microelectronic system is bridged between the controlling and stimulated nerve, the relevant motion of legs and nerve signal waveforms, which are stimulated by the evoked or spontaneous nerve signal through such a system, have been observed. Therefore, the feasibility of the presented method was demonstrated.

  19. Distribution of tadpoles of Ollotis occidentalis (Amphibia: Anura: Bufonidae along the Río Salado, Puebla, México

    Directory of Open Access Journals (Sweden)

    Guillermo A. Woolrich-Piña


    Full Text Available We examined monthly variation in the characteristics of river sections along the Río Salado (Puebla, Mexico and how these factors were associated with the dis- tribution of the tadpoles of the toad Ollotis occidentalis. Tadpoles were observed in the river in March 2007, and from November 2007 through February 2008 and were only found in the main river channel. Sections of the Río Salado with tadpoles were deeper, wider, and longer than sections without tadpoles. Dissolved oxygen levels were higher and salinity was lower in river sections with tadpoles compared to the sections without tadpoles. There was no difference in temperature between sections with and without tadpoles. Tadpoles were found in river sections that contained more vegeta- tion than river section without tadpoles. Our results suggest that the distribution of tadpoles of O. occidentalis is related to the permanence of water, the chemical nature of the water, and the presence of vegetation.

  20. Ground Water Chemistry Changes before Major Earthquakes and Possible Effects on Animals (United States)

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


    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

  1. Ranavirus could facilitate local extinction of rare amphibian species. (United States)

    Earl, Julia E; Chaney, Jordan C; Sutton, William B; Lillard, Carson E; Kouba, Andrew J; Langhorne, Cecilia; Krebs, Jessi; Wilkes, Rebecca P; Hill, Rachel D; Miller, Debra L; Gray, Matthew J


    There is growing evidence that pathogens play a role in population declines and species extinctions. For small populations, disease-induced extinction may be especially probable. We estimated the susceptibility of two amphibian species of conservation concern (the dusky gopher frog [Lithobates sevosus] and boreal toad [Anaxyrus boreas boreas]) to an emerging pathogen (ranavirus) using laboratory challenge experiments, and combined these data with published demographic parameter estimates to simulate the potential effects of ranavirus exposure on extinction risk. We included effects of life stage during pathogen exposure, pathogen exposure interval, hydroperiod of breeding habitat, population carrying capacity, and immigration in simulations. We found that both species were highly susceptible to ranavirus when exposed to the pathogen in water at environmentally relevant concentrations. Dusky gopher frogs experienced 100 % mortality in four of six life stages tested. Boreal toads experienced 100 % mortality when exposed as tadpoles or metamorphs, which were the only life stages tested. Simulations showed population declines, greater extinction probability, and faster times to extinction with ranavirus exposure. These effects were more evident with more frequent pathogen exposure intervals and lower carrying capacity. Immigration at natural rates did little to mitigate effects of ranavirus exposure unless immigration occurred every 2 years. Our results demonstrate that disease-induced extinction by emerging pathogens, such as ranavirus, is possible, and that threat may be especially high for species with small population sizes. For the species in this study, conservation organizations should incorporate ranavirus surveillance into monitoring programs and devise intervention strategies in the event that disease outbreaks occur.

  2. Climate forcing of an emerging pathogenic fungus across a montane multi-host community (United States)

    Clare, Frances C.; Halder, Julia B.; Daniel, Olivia; Bielby, Jon; Semenov, Mikhail A.; Jombart, Thibaut; Loyau, Adeline; Schmeller, Dirk S.; Cunningham, Andrew A.; Rowcliffe, Marcus; Bosch, Jaime


    Changes in the timings of seasonality as a result of anthropogenic climate change are predicted to occur over the coming decades. While this is expected to have widespread impacts on the dynamics of infectious disease through environmental forcing, empirical data are lacking. Here, we investigated whether seasonality, specifically the timing of spring ice-thaw, affected susceptibility to infection by the emerging pathogenic fungus Batrachochytrium dendrobatidis (Bd) across a montane community of amphibians that are suffering declines and extirpations as a consequence of this infection. We found a robust temporal association between the timing of the spring thaw and Bd infection in two host species, where we show that an early onset of spring forced high prevalences of infection. A third highly susceptible species (the midwife toad, Alytes obstetricans) maintained a high prevalence of infection independent of time of spring thaw. Our data show that perennially overwintering midwife toad larvae may act as a year-round reservoir of infection with variation in time of spring thaw determining the extent to which infection spills over into sympatric species. We used future temperature projections based on global climate models to demonstrate that the timing of spring thaw in this region will advance markedly by the 2050s, indicating that climate change will further force the severity of infection. Our findings on the effect of annual variability on multi-host infection dynamics show that the community-level impact of fungal infectious disease on biodiversity will need to be re-evaluated in the face of climate change. This article is part of the themed issue ‘Tackling emerging fungal threats to animal health, food security and ecosystem resilience’. PMID:28080980

  3. Preparation of mPEG2000-PLA-modified Xingnaojing microemulsion and evaluation in mucosal irritation. (United States)

    Wen, Ran; Li, Huiyun; Du, Shouying; Zhao, Xuejiao; Zhao, Zhuang; Bai, Jie; Lu, Yang


    Xingnaojing microemulsion (XNJ-M) administered intranasally is used for stroke treatment. Methoxy poly(ethylene glycol)-poly(lactide) (mPEG-PLA) is a block copolymer with surfactant-like properties and good biodegradability and reliable biological safety. In order to investigate the possibility to lower mucosa irritation with XNJ-M, XNJ-M modified by mPEG2000-PLA (XNJ-MM) was prepared. Different ratios of mPEG2000-PLA were synthesized. The structures and properties were confirmed by 1H-NMR, IR, and DSC. The hydrophile-lipophile balance (HLB) value and critical micellar concentration of copolymers were investigated. The in situ toad palate model was adopted to investigate the ciliotoxicity of the copolymers. The XNJ-M and XNJ-MM were prepared by dropping aqueous phase method. Mucosal irritation of different Xingnaojing (XNJ) preparations was studied by behavioral observations including sneezing and scratching nose. The epithelial thickness of nasal mucosa was evaluated and the secretory protein concentration was determined. The results of in situ toad palate model demonstrated that high HLB value mPEG2000-PLA basically showed no ciliotoxicity, while EL-35 had significant dose-dependent ciliotoxicity (PPLA were significantly lower than EL-35 after seven days of treatment, based on the epithelial thickness of 0.429±0.100 mm and 0.700±0.035 mm, respectively (PPLA-modified microemulsion is a promising dosage form of XNJ, based on reduced irritation on nasal mucosa.

  4. Ground water chemistry changes before major earthquakes and possible effects on animals. (United States)

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


    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.

  5. Ecological strategies predict associations between aquatic and genetic connectivity for dryland amphibians. (United States)

    Mims, Meryl C; Phillipsen, Ivan C; Lytle, David A; Kirk, Emily E Hartfield; Olden, Julian D


    The study of how population genetic structure is shaped by attributes of the environment is a central scientific pursuit in ecology and conservation. But limited resources may prohibit landscape genetics studies for many threatened species, particularly given the pace of current environmental change. Understanding the extent to which species' ecological strategies--their life histories, biology, and behavior-predict patterns and drivers of population connectivity is a critical step in evaluating the potential of multi-taxa inference in landscape genetics. We present results of a landscape genetic study of three dryland amphibians: the canyon treefrog (Hyla arenicolor), red-spotted toad (Anaxyrus punctatus), and Mexican spadefoot (Spea multiplicata). These species characterize a range of ecological strategies, driven primarily by different water dependencies, enabling amphibian survival in arid and semiarid environments. We examined a suite of hypothesized relationships between genetic connectivity and landscape connectivity across species. We found a positive relationship between population differentiation and water dependency, e.g., longer larval development periods and site fidelity for reliable water sources. We also found that aquatic connectivity is important for all species, particularly when considered with topography (slope). The effect of spatial scale varied by species, with canyon treefrogs and Mexican spadefoots characterized by relatively consistent results at different scales in contrast to the stark differences in results for red-spotted toads at different scales. Using ecological information to predict relationships between genetic and landscape connectivity is a promising approach for multi-taxa inference and may help inform conservation efforts where single-species genetic studies are not possible.

  6. Hybrid female mate choice as a species isolating mechanism: environment matters. (United States)

    Schmidt, E M; Pfennig, K S


    A fundamental goal of biology is to understand how new species arise and are maintained. Female mate choice is potentially critical to the speciation process: mate choice can prevent hybridization and thereby generate reproductive isolation between potentially interbreeding groups. Yet, in systems where hybridization occurs, mate choice by hybrid females might also play a key role in reproductive isolation by affecting hybrid fitness and contributing to patterns of gene flow between species. We evaluated whether hybrid mate choice behaviour could serve as such an isolating mechanism using spadefoot toad hybrids of Spea multiplicata and Spea bombifrons. We assessed the mate preferences of female hybrid spadefoot toads for sterile hybrid males vs. pure-species males in two alternative habitat types in which spadefoots breed: deep or shallow water. We found that, in deep water, hybrid females preferred the calls of sterile hybrid males to those of S. multiplicata males. Thus, maladaptive hybrid mate preferences could serve as an isolating mechanism. However, in shallow water, the preference for hybrid male calls was not expressed. Moreover, hybrid females did not prefer hybrid calls to those of S. bombifrons in either environment. Because hybrid female mate choice was context-dependent, its efficacy as a reproductive isolating mechanism will depend on both the environment in which females choose their mates as well as the relative frequencies of males in a given population. Thus, reproductive isolation between species, as well as habitat specific patterns of gene flow between species, might depend critically on the nature of hybrid mate preferences and the way in which they vary across environments.

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

    Directory of Open Access Journals (Sweden)

    Friedemann T. Freund


    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. Bioacustical and etho-ecological features in amphibian communities of Southern Cordoba province (Argentina

    Directory of Open Access Journals (Sweden)

    Salas, Nancy E.


    standardized monitoring practices. In the present work, the most important etho-ecological differences (reproduction habitat, call site, daily and seasonal activity of species that constitute the communities of southern Cordoba Province are indicated, and a classification of advertisement calls is provided. The anuran fauna of the plain area of the southern-central Córdoba Province is represented by 9 species of leptodactylids belonging to 5 genera (Leptodactylus gracilis, L. mystacinus, L. latinasus latinasus, L. ocellatus, Pleurodema tucumanum, Physalaemus biligonigerus, Odontophlynus americanus, Ceratophrys cranwelli and C. ornata, 2 species of bufonids (Bufo arenarum and B. fernandezae and one hylid (Hyla pulchella pulchella. The acoustic records obtained in the field during the reproductive period were analyzed through a program of sound digital analysis comparing the following parameters: dominant frequency, call duration and interval between calls; descriptions regarding type of call and modulation were also made. Three types of basic calls were recognized based on duration; this category was sub-divided depending on the shape of the oscillographic image. Results of this analysis revea] marked differences between advertisement calls, mainly at the level of dominant frequency ranges and call duration. This partition of sound space represents a mechanism of mating isolation that minimizes the interaction between sympatric species that breed at the same time.

  9. 两种无尾类发声器官的初步观察%Preliminary observation of vocal organs of two anurans (Rana chensinensis and Bufo raddei)(Anura)

    Institute of Scientific and Technical Information of China (English)

    张雷; 赵梓伊; 陆宇燕; 李丕鹏; 宋阳; 周正彦; 周兵; 杨宝田; 董丙君


    Vocal organs in Rana chensinensis were preliminarily compared with Bufo raddei with anatomic and histological methods. The results shown that Rana chensinensis had cartilago prearytenoedeas and pulvinaria vocalias, but Bufo raddei did not have. The lateral portions of vocal cords in Bufo raddei were a pair of membranes composed of dense regular connective tissues, and in the mid of medial portion of vocal cords in Bufo raddei there are a pair of fibrious masses. At the end of laryngeal chambers Bufo raddei there are also a pair of posterior membrances. But the lateral portions of vocal cords in Rana chensinensis were composed of dense irregular connective tissues and had no posterior membrances. The difference of areas in medial portions of vocal cords were apparent in Rana chensinensis but in Bufo raddei no this character. The type of vocal sacs in Rana chensinensis was inner vocal sacs lateral to pharynx, but in Bufo raddei it was inner vocal sacs under pharynx. Compared with the two(Rana chensinensis and Bufo raddei) relative length and width of medial portions of vocal cords and laryngeal chambers, the results have statistics significance. In discussion, we analysized the influence of both vocal organs on sound production and it would supply basic information to understand the sounds difference in Bufonids and Ranids.%应用大体解剖和组织学方法对中国林蛙(Rana chensinensis)和花背蟾蜍(Bufo raddei)的发声器官进行了初步观察和比较.结果表明:中国林蛙有独立的前杓状软骨和枕声带,而花背蟾蜍则没有上述结构.花背蟾蜍的声带侧部为规则致密结缔组织构成的膜状结构,并且前端有一对肉质化的纤维小球,喉室末端有一对后膜,而中国林蛙的声带侧部由无规则致密结缔组织构成的肉质化纤维柱状结构,喉室的末端无后膜结构.前者的声带中部为一对厚度均匀的膜系结构.而后者声带中部在不同区域也存在明显的差异,中国林

  10. 蟾蜍高钾血症模型的建立%Reproduction of a hyperkalemia animal model

    Institute of Scientific and Technical Information of China (English)

    霍健; 苏兴利; 王爽


    Objective To reproduce an animal mode! Of myocardium hyperkalemia and to relieve its symptoms with calcium chloride (CaCU) with the purpose of observing the effect of hyperkalemia on electrocardiogram Ⅱ (ECGⅡ). Methods Fifty toads (either gender) were assigned into two groups, I. E. Experiment group and control group. Animals in experiment group were injected with 0. 3ml of 0.2% potassium chloride (KC1) via abdominal vein to reproduce hyperkalemia model, while those in control group were injected same amount of 0. 9% sodium chloride (NaCl), then ECG Ⅱ was synchronously recorded. Two minutes later, animals in experiment group were injected with 0. 2ml of 1% calcium chloride (CaCk) via the abdominal vein to relieve hyperkalemia, and ECGⅡ was again synchronously recorded. Results After injection of 0.2% KC1, ECG Ⅱ of the animals in experiment group showed that the heart rate was slowed down (P<0.05), P-R interval was extended ( P<0.05), QRS was broadened and lowered ( P<0.05), T peak became higher ( P<0.05) as compared with that in control group. Two minutes after injection of 1% CaCk , the ECG U of the animals in experiment group recovered to normal status, and no significant difference was found between that of experiment group and control group. Conclusion The changes in ECG Ⅱ in toad model of myocardium hyperkalemia, produced by injection of 0.2% KCl, and then relieve the symptoms by injection of 1% CaCk via abdominal vein, is similar to that in mammals. Compared with other animal models, the hyperkalemia toad model is more convenient to be established with practical and stable result, and the cost is lower.%目的 建立蟾蜍心脏高钾血症和氯化钙解救动物模型,观察血钾升高及氯化钙解救对蟾蜍Ⅱ导联心电图(ECGⅡ)的影响.方法 蟾蜍50只,雌雄不拘,随机均分为实验组和对照组(n=25).实验组经腹壁静脉注射0.2%氯化钾0.3ml,2rnin后经腹壁静脉注射1%氯化钙0.2ml,对照组均注射等量生理

  11. Food as a source of dioxin exposure in the residents of Bien Hoa City, Vietnam. (United States)

    Schecter, Arnold; Quynh, Hoang Trong; Pavuk, Marian; Päpke, Olaf; Malisch, Rainer; Constable, John D


    Recently, elevated dioxin levels, over 5 parts per trillion (ppt) 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), from Agent Orange was reported in 95% of 43 selected residents of Bien Hoa City, a city in southern Vietnam near a former air base used for Agent Orange-spraying missions. Agent Orange herbicide, contaminated with TCDD, was sprayed in Vietnam between 1962 and 1971 primarily for use as a defoliant. Typical blood TCCD levels are 2 ppt in Vietnamese, but levels are as high as 413 ppt in Bien Hoa City. Elevated TCDD was found in children born many years after Agent Orange spraying ended and in immigrants from non-Agent Orange-sprayed parts of Vietnam, which documented new exposures. Extremely elevated soil TCDD samples, over 1 million ppt, and elevated TCDD in sediment were found in some nearby areas such as Bien Hung Lake. The primary route of intake of almost all dioxins in humans is food. However, in our prior studies in Bien Hoa, food was unavailable for dioxin analysis so the route of intake was not confirmed. In the 1970s, while Agent Orange was still being sprayed, elevated human milk TCDD levels as high as 1850 were detected in milk from Vietnamese people living in Agent Orange-sprayed areas where consumption of fish was high. Furthermore, also in the 1970s, elevated TCDD levels (up to 810 ppt) were found in fish and shrimp from the same area as the milk donors. In the 1980s, we found elevated TCDD and also other organohalogen levels in human tissue, pork, fish, a turtle, and a snake in Southern Vietnam. For these reasons, we recently collected food from Bien Hoa and analyzed it for dioxins, polychlorinated biphenyls (PCBs), DDT and its metabolites, and other organochlorines. We found marked elevation of TCDD, the dioxin characteristic of Agent Orange, in some of the food products, including ducks with 276 ppt and 331 ppt wet weight, chickens from 0.031-15 ppt wet weight, fish from 0.063-65 ppt wet weight, and a toad with 56 ppt wet weight. Usual TCDD

  12. Proteasome Inhibition Contributed to the Cytotoxicity of Arenobufagin after Its Binding with Na, K-ATPase in Human Cervical Carcinoma HeLa Cells.

    Directory of Open Access Journals (Sweden)

    Qingxi Yue

    Full Text Available Although the possibility of developing cardiac steroids/cardiac glycosides as novel cancer therapeutic agents has been recognized, the mechanism of their anticancer activity is still not clear enough. Toad venom extract containing bufadienolides, which belong to cardiac steroids, has actually long been used as traditional Chinese medicine in clinic for cancer therapy in China. The cytotoxicity of arenobufagin, a bufadienolide isolated from toad venom, on human cervical carcinoma HeLa cells was checked. And, the protein expression profile of control HeLa cells and HeLa cells treated with arenobufagin for 48 h was analyzed using two-dimensional electrophoresis, respectively. Differently expressed proteins in HeLa cells treated with arenobufagin were identified and the pathways related to these proteins were mapped from KEGG database. Computational molecular docking was performed to verify the binding of arenobufagin and Na, K-ATPase. The effects of arenobufagin on Na, K-ATPase activity and proteasome activity of HeLa cells were checked. The protein-protein interaction network between Na, K-ATPase and proteasome was constructed and the expression of possible intermediate proteins ataxin-1 and translationally-controlled tumor protein in HeLa cells treated with arenobufagin was then checked. Arenobufagin induced apoptosis and G2/M cell cycle arrest in HeLa cells. The cytotoxic effect of arenobufagin was associated with 25 differently expressed proteins including proteasome-related proteins, calcium ion binding-related proteins, oxidative stress-related proteins, metabolism-related enzymes and others. The results of computational molecular docking revealed that arenobufagin was bound in the cavity formed by the transmembrane alpha subunits of Na, K-ATPase, which blocked the pathway of extracellular Na+/K+ cation exchange and inhibited the function of ion exchange. Arenobufagin inhibited the activity of Na, K-ATPase and proteasome, decreased the

  13. A quantitative determination of air-water heat fluxes in Hermit Lake, New Hampshire under varying meteorological conditions, time of day, and time of year (United States)

    Kyper, Nicholas D.

    An extensive heat flux study is performed at Hermit Lake, New Hampshire from May 26, 2010 till November 7, 2010 to determine the effects of the five individual heat fluxes on Hermit Lake and the surrounding amphibian community. Hermit Lake was chosen due to the relatively long meteorological observations record within the White Mountains of New Hampshire, a new lakeside meteorological station, and ongoing phenology studies of the surrounding eco-system. Utilizing meteorological data from the lakeside weather station and moored water temperature sensors, the incident (Qi), blackbody ( Qbnet ), latent (Qe), sensible (Q s), and net (Qn) heat fluxes are calculated. The incident heat flux is the dominate term in the net flux, accounting for 93% of the variance found in Qn and producing a heat gain of ˜ 19x108 J m-2 throughout the period of study. This large gain produces a net gain of heat in the lake until October 1, 2010, where gains by Qi are offset by the large combined losses of Qbnet , Qs, and Qe thereby producing a gradual decline of heat within the lake. The latent and blackbody heat fluxes produce the largest losses of heat in the net heat flux with a total losses of ˜ -8x108 J m-2 and ˜ -7x108 J m-2, respectively. The sensible heat flux is negligible, producing a total minimal loss of ˜ -1x108 J m-2. Overall the net heat produces a net gain of heat of 2x108 J m-2 throughout the study period. Frog calls indicative of breeding are recorded from May 26, 2010 until August 16, 2010. The spring peeper, American toad, and green frog each produced enough actively calling days to be compared to air temperature, surface water temperature, and wind speed data, as well as data from the five heat fluxes. Linear regression analysis reveals that certain water temperature thresholds affect the calling activities of the spring peeper and green frog, while higher wind speeds have a dramatic effect on the calling activities of both the green frog and American toad. All three

  14. 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: [Department of Ecology, University of Calabria, Via P. Bucci, 87036 Rende (Cosenza) (Italy)


    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

  15. Do lower vertebrates suffer from motion sickness? (United States)

    Lychakov, Dmitri

    The poster presents literature data and results of the author’s studies with the goal to find out whether the lower animals are susceptible to motion sickness (Lychakov, 2012). In our studies, fish and amphibians were tested for 2 h and more by using a rotating device (f = 0.24 Hz, a _{centrifugal} = 0.144 g) and a parallel swing (f = 0.2 Hz, a _{horizontal} = 0.059 g). The performed studies did not revealed in 4 fish species and in toads any characteristic reactions of the motion sickness (sopite syndrome, prodromal preparatory behavior, vomiting). At the same time, in toads there appeared characteristic stress reactions (escape response, an increase of the number of urinations, inhibition of appetite), as well as some other reactions not associated with motion sickness (regular head movements, eye retractions). In trout fry the used stimulation promoted division of the individuals into the groups differing by locomotor reaction to stress, as well as the individuals with the well-expressed compensatory reaction that we called the otolithotropic reaction. Analysis of results obtained by other authors confirms our conclusions. Thus, the lower vertebrates, unlike mammals, are immune to motion sickness either under the land conditions or under conditions of weightlessness. On the basis of available experimental data and theoretical concepts of mechanisms of development the motion sickness, formulated in several hypotheses (mismatch hypothesis, Traisman‘ s hypothesis, resonance hypothesis), there presented the synthetic hypothesis of motion sickness that has the conceptual significance. According to the hypothesis, the unusual stimulation producing sensor-motor or sensor-sensor conflict or an action of vestibular and visual stimuli of frequency of about 0.2 Hz is perceived by CNS as poisoning and causes the corresponding reactions. The motion sickness actually is a byproduct of technical evolution. It is suggested that in the lower vertebrates, unlike mammals

  16. Neural transduction in Xenopus laevis lateral line system. (United States)

    Strelioff, D; Honrubia, V


    1. The process of neural excitation in hair cell systems was studied in an in vitro preparation of the Xenopus laevis (African clawed toad) lateral line organ. A specially designed stimulus chamber was used to apply accurately controlled pressure, water movement, or electrical stimuli, and to record the neural responses of the two afferent fibers innervating each organ or stitch. The objective of the study was to determine the characteristics of the neural responses to these stimuli, and thus gain insight into the transduction process. 2. A sustained deflection of the hair cell cilia due to a constant flow of water past the capula resulted in a maintained change in the mean firing rate (MFR) of the afferent fibers. The data also demonstrated that the neural response was proportional to the velocity of the water flow and indicated that both deflection and movement of the cilia were the effective physiological stimuli for this hair cell system. 3. The preparations responded to sinusoidal water movements (past the capula) over the entire frequency range of the stimulus chamber, 0.1-130 Hz, and were most sensitive between 10 and 40 Hz. The variation of the MFR and the percent modulation indicated that the average dynamic range of each organ was 23.5 dB. 4. The thresholds, if any, for sustained pressure changes and for sinusoidal pressure variations in the absence of water movements were very high. Due to the limitations of the stimulus chamber it was not possible to generate pressure stimuli of sufficient magnitude to elicit a neural response without also generating suprathreshold water-movement stimuli. Sustained pressures had no detectable effect on the neural response to water-movement stimuli. 5. The preparations were very sensitive to electrical potentials applied across the toad skin on which the hair cells were located. Potentials which made the ciliated surfaces of the hair cells positive with respect to their bases increased the MFR of the fibers, whereas

  17. Proteasome Inhibition Contributed to the Cytotoxicity of Arenobufagin after Its Binding with Na, K-ATPase in Human Cervical Carcinoma HeLa Cells. (United States)

    Yue, Qingxi; Zhen, Hong; Huang, Ming; Zheng, Xi; Feng, Lixing; Jiang, Baohong; Yang, Min; Wu, Wanying; Liu, Xuan; Guo, Dean


    Although the possibility of developing cardiac steroids/cardiac glycosides as novel cancer therapeutic agents has been recognized, the mechanism of their anticancer activity is still not clear enough. Toad venom extract containing bufadienolides, which belong to cardiac steroids, has actually long been used as traditional Chinese medicine in clinic for cancer therapy in China. The cytotoxicity of arenobufagin, a bufadienolide isolated from toad venom, on human cervical carcinoma HeLa cells was checked. And, the protein expression profile of control HeLa cells and HeLa cells treated with arenobufagin for 48 h was analyzed using two-dimensional electrophoresis, respectively. Differently expressed proteins in HeLa cells treated with arenobufagin were identified and the pathways related to these proteins were mapped from KEGG database. Computational molecular docking was performed to verify the binding of arenobufagin and Na, K-ATPase. The effects of arenobufagin on Na, K-ATPase activity and proteasome activity of HeLa cells were checked. The protein-protein interaction network between Na, K-ATPase and proteasome was constructed and the expression of possible intermediate proteins ataxin-1 and translationally-controlled tumor protein in HeLa cells treated with arenobufagin was then checked. Arenobufagin induced apoptosis and G2/M cell cycle arrest in HeLa cells. The cytotoxic effect of arenobufagin was associated with 25 differently expressed proteins including proteasome-related proteins, calcium ion binding-related proteins, oxidative stress-related proteins, metabolism-related enzymes and others. The results of computational molecular docking revealed that arenobufagin was bound in the cavity formed by the transmembrane alpha subunits of Na, K-ATPase, which blocked the pathway of extracellular Na+/K+ cation exchange and inhibited the function of ion exchange. Arenobufagin inhibited the activity of Na, K-ATPase and proteasome, decreased the expression of Na, K

  18. phylogeography of the phrynocephalus vlangalii species complex in the upper reaches of the yellow river inferred from mtdna nd4-trnaleu segments

    Institute of Scientific and Technical Information of China (English)


    the ching hai toad-headed agama (phrynocephalus vlangalii) complex is a small toad-headed viviparous lizard that is endemic to the qinghai-tibetan plateau.a fragment of mtdna nd4-trnaleu from 189 samples in 26 populations was used to infer the phylogeographic history of this species complex in the upper reaches of the yellow river.phylogenetic analyses revealed that p.vlangalii and another proposed species (p.putjatia) do not form a monophyletic mtdna clade,which in contrast with a previous study,includes p.theobaldi and p forsythii.lineage diversification occurred in the middle pleistocene for p.vlangali (ca.0.95 ma) and in the early pleistocene for p.putjatia (ca.1.78 ma).the uplift of the a'nyemaqen mountains and glaciations since the mid-late pleistocene,especially during the kunlun glaciation,are considered to have promoted the allopartric divergence of p vlangalii.the diversification of p.putjatia may be triggered by the tectonic movement in the huangshui river valley during the c phase of qingzang movement.subsequently,the glacial climate throughout the pleistocene may have continuedto impede the gene flow of p.putjatia,eventually resulting in the genetic divergence of p.putjatia in the allopatric regions.demographic estimates revealed weak population expansion in one lineage of p vlangalii (a2,the qaidam basin lineage) and one lineage of p.putjatia (b2,the north qinghai lake lineage) after approximately 42 000 years before present.however,constant population size through time was inferred for two lineages (a1 and b1),the source of yellow river lineage of p.vlangalii and the southeast of qinghai lake lineage of p putjatia,possibly due to stable populations persisting in areas unaffected by glacial advances.our results also suggest:1) at least four differentiated lineages of p.vlangalii complex may have evolved allopatrically in different regions during the pleistocene glaciation events; 2) in support of several recent studies,p.putjatia is a valid species

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

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


    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.

  20. Sexual Dimorphism of Head Size in Phrynocephalus przewalskii:Testing the Food Niche Divergence Hypothesis

    Institute of Scientific and Technical Information of China (English)

    Wei ZHAO; Naifa LIU


    Sexual size dimorphism (SSD) is a general phenomenon in lizards, and can evolve through sexual selection or natural selection. But natural selection, which was thought to operate mainly through reducing the competition be-tween the two sexes (niche divergence hypothesis), gave rise to a lot of controversy. We tested the niche divergence hypothesis in the toad-headed lizard Phrynocephalus przewalskii by comparing diet composition and prey sizes between males and females. The species was found to be sexual dimorphic, with males having relatively larger snout-vent length, head width, head length, and tail length, while females have relatively larger abdomen length. Based on analysis of 93 studied stomachs, a total of 1359 prey items were identiifed. The most common prey items were formicid, lygaeid and tenebrionid. The two sexes did not differ in the relative proportions of prey size categories they consumed and the dietary overlap based on prey species was high (O=0.989). In addition, the meal size, the volume or any maximal dimension of the largest prey item in the stomach was not explained by the sexes. According to our results, food niche divergence might not play an important role in the SSD evolution of P. przewalskii.

  1. Predator interference effects on biological control: The "paradox" of the generalist predator revisited (United States)

    Parshad, Rana D.; Bhowmick, Suman; Quansah, Emmanuel; Basheer, Aladeen; Upadhyay, Ranjit Kumar


    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.

  2. Lucilia silvarum Meigen, 1826 (Diptera: Calliphoridae)--a new species of interest for forensic entomology in Europe. (United States)

    Fremdt, Heike; Szpila, Krzysztof; Huijbregts, Johannes; Lindström, Anders; Zehner, Richard; Amendt, Jens


    In Europe, the blowfly genus Lucilia is represented in Forensic Entomology mainly by the species L. ampullacea, L. caesar, L. illustris and L. sericata. In the US, Lucilia silvarum is rarely recorded as a carrion breeding species but usually as a more or less exclusive parasite of frogs and toads. We present three forensic cases from different European countries reporting, for the first time, L. silvarum on human bodies that were found close to lakes, wetlands, or riversides. To use this species for post-mortem interval estimations, thermal development data is needed. The first step is accurate identification by morphological and molecular means. Therefore, we analysed a 611 bp part of the mitochondrial COI region for 23 specimens of L. silvarum from 9 different geographical regions, all of which give the same haplotype. Differences within the haplotype varied by up to 0.2%. Comparison between the haplotype found and those published on GenBank showed up to 1.2% variance. Moreover, we present an updated key for the morphological identification of the third larval instars of European Lucilia spp. of forensic importance, adding not only L. silvarum, but also L. cuprina which was recorded in Europe for the first time about 20 years ago.

  3. Lanfrediella amphicirrus gen. nov. sp. nov. Nematotaeniidae (Cestoda: Cyclophyllidea, a tapeworm parasite of Rhinella marina (Linnaeus, 1758 (Amphibia: Bufonidae

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    Francisco Tiago de Vasconcelos Melo


    Full Text Available The family Nematotaeniidae, tapeworms commonly found in the small intestines of amphibians and reptiles, includes 27 recognised species distributed among four genera: Bitegmen Jones, Cylindrotaenia Jewell, Distoichometra Dickey and Nematotaenia Lühe. The taxonomy of these cestodes is poorly defined, due in part to the difficulties of observing many anatomical traits. This study presents and describes a new genus and species of nematotaeniid parasite found in cane toads (Rhinella marina from eastern Brazilian Amazonia. The cestodes were collected during the necropsy of 20 hosts captured in the urban area of Belém, Pará. The specimens were fixed and processed for light microscopy, scanning electron microscopy (SEM and three-dimensional (3D reconstruction. Samples were also collected for molecular analyses. The specimens presented a cylindrical body, two testes and paruterine organs. However, they could not be allocated to any of the four existing nematotaeniid genera due to the presence of two each of dorsal compact medullary testes, cirri, cirrus pouches, genital pores, ovaries and vitelline glands per mature segment. Lanfrediella amphicirrus gen. nov. sp. nov. is the first nematotaeniid studied using Historesin analysis, SEM and 3D reconstruction, and it is the second taxon for which molecular data have been deposited in GenBank.

  4. Mesodermal origin of median fin mesenchyme and tail muscle in amphibian larvae. (United States)

    Taniguchi, Yuka; Kurth, Thomas; Medeiros, Daniel Meulemans; Tazaki, Akira; Ramm, Robert; Epperlein, Hans-Henning


    Mesenchyme is an embryonic precursor tissue that generates a range of structures in vertebrates including cartilage, bone, muscle, kidney, and the erythropoietic system. Mesenchyme originates from both mesoderm and the neural crest, an ectodermal cell population, via an epithelial to mesenchymal transition (EMT). Because ectodermal and mesodermal mesenchyme can form in close proximity and give rise to similar derivatives, the embryonic origin of many mesenchyme-derived tissues is still unclear. Recent work using genetic lineage tracing methods have upended classical ideas about the contributions of mesodermal mesenchyme and neural crest to particular structures. Using similar strategies in the Mexican axolotl (Ambystoma mexicanum), and the South African clawed toad (Xenopus laevis), we traced the origins of fin mesenchyme and tail muscle in amphibians. Here we present evidence that fin mesenchyme and striated tail muscle in both animals are derived solely from mesoderm and not from neural crest. In the context of recent work in zebrafish, our experiments suggest that trunk neural crest cells in the last common ancestor of tetrapods and ray-finned fish lacked the ability to form ectomesenchyme and its derivatives.

  5. Do parasitic trematode cercariae demonstrate a preference for susceptible host species?

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    Brittany F Sears

    Full Text Available Many parasites are motile and exhibit behavioural preferences for certain host species. Because hosts can vary in their susceptibility to infections, parasites might benefit from preferentially detecting and infecting the most susceptible host, but this mechanistic hypothesis for host-choice has rarely been tested. We evaluated whether cercariae (larval trematode parasites prefer the most susceptible host species by simultaneously presenting cercariae with four species of tadpole hosts. Cercariae consistently preferred hosts in the following order: Anaxyrus ( = Bufo terrestris (southern toad, Hyla squirella (squirrel tree frog, Lithobates ( = Rana sphenocephala (southern leopard frog, and Osteopilus septentrionalis (Cuban tree frog. These host species varied in susceptibility to cercariae in an order similar to their attractiveness with a correlation that approached significance. Host attractiveness to parasites also varied consistently and significantly among individuals within a host species. If heritable, this individual-level host variation would represent the raw material upon which selection could act, which could promote a Red Queen "arms race" between host cues and parasite detection of those cues. If, in general, motile parasites prefer to infect the most susceptible host species, this phenomenon could explain aggregated distributions of parasites among hosts and contribute to parasite transmission rates and the evolution of virulence. Parasite preferences for hosts belie the common assumption of disease models that parasites seek and infect hosts at random.

  6. From frog integument to human skin: dermatological perspectives from frog skin biology. (United States)

    Haslam, Iain S; Roubos, Eric W; Mangoni, Maria Luisa; Yoshizato, Katsutoshi; Vaudry, Hubert; Kloepper, Jennifer E; Pattwell, David M; Maderson, Paul F A; Paus, Ralf


    For over a century, frogs have been studied across various scientific fields, including physiology, embryology, neuroscience, (neuro)endocrinology, ecology, genetics, behavioural science, evolution, drug development, and conservation biology. In some cases, frog skin has proven very successful as a research model, for example aiding in the study of ion transport through tight epithelia, where it has served as a model for the vertebrate distal renal tubule and mammalian epithelia. However, it has rarely been considered in comparative studies involving human skin. Yet, despite certain notable adaptations that have enabled frogs to survive in both aquatic and terrestrial environments, frog skin has many features in common with human skin. Here we present a comprehensive overview of frog (and toad) skin ontogeny, anatomy, cytology, neuroendocrinology and immunology, with special attention to its unique adaptations as well as to its similarities with the mammalian integument, including human skin. We hope to provide a valuable reference point and a source of inspiration for both amphibian investigators and mammalian researchers studying the structural and functional properties of the largest organ of the vertebrate body.

  7. Developmental alterations and osmoregulatory physiology of a larval anuran under osmotic stress. (United States)

    Gomez-Mestre, I; Tejedo, M; Ramayo, E; Estepa, J


    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 under saline conditions (ranging between 85 and 200 mOsm) showed a slower developmental rate, metamorphosing between 4 and 9 d later than the controls. Bufo calamita tadpoles reared in brackish water increased their osmolality and solute concentration (mainly sodium and chloride), decreased their levels of glucose, and decreased the total protein content, all measured from whole-animal extracts. Although most larval anurans are strictly ammoniotelic until the completion of metamorphosis, a few species exposed to dehydrating environments have evolved the ability to use urea as an osmolyte during the larval phase. The data presented here reveal that although B. calamita seems to be yet another exception to the rule of larval strict ammoniotelism, the tadpoles are not able to use urea as an osmolyte and rely on sodium-chloride balance instead. Preliminary immunoassays of thyroid hormone content suggest a possible decrease in hormone levels induced in water salinity conditions that correlate with a decreased developmental rate.

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

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    Bingduo Zhou


    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.

  9. Xenopus laevis a success story of biological research in space (United States)

    Horn, Eberhard R.


    The clawed toad Xenopus laevis is a common experimental animal used in many disciplines of life sciences, such as integrative, developmental and molecular biology or experimental medicine. Since 30 years, Xenopus is used in biological research in space. Important milestones were the years 1975, when Xenopus embryos flew for the first time on the Russian space station Salut-4 and 1994, when Xenopus eggs were successfully fertilized for the first time in space during the Japanese Spacelab mission STS-47 and developed in microgravity to vital tadpoles. Most Xenopus studies were related to embryogenesis and development. Observations during and after altered gravity revealed changes such as the thickening of the blastocoel roof, the dorsalization of the tail, and modifications of vestibular reflexes, fictive and freely swimming. Many changes were reversible even during microgravity exposure. Studies about the vestibuloocular reflex or synapse formation revealed an age-related sensitivity to altered gravity. Xenopus offers useful tools for studies about microgravity effects on living systems. Its oocyte is a suitable model to study ion channel function in space; the dorsalization model can be used to analyse growth factor sensibilities. Hardware for life support of adults, tadpoles and embryos (cf. SUPPLY unit in combination with miniaquaria) as well as for controlled experiments in space are prerequisites for an extension of research with Xenopus. The application aspect is based on the fact that fundamental research per se brings benefit to man.

  10. Triggering Apoptotic Death of Human Malignant Melanoma A375.S2 Cells by Bufalin: Involvement of Caspase Cascade-Dependent and Independent Mitochondrial Signaling Pathways

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    Yu-Ping Hsiao


    Full Text Available Bufalin was obtained from the skin and parotid venom glands of toad and has been shown to induce cytotoxic effects in various types of cancer cell lines, but there is no report to show that whether bufalin affects human skin cancer cells. The aim of this investigation was to study the effects of bufalin on human malignant melanoma A375.S2 cells and to elucidate possible mechanisms involved in induction of apoptosis. A375.S2 cells were treated with different concentrations of bufalin for a specific time period and investigated for effects on apoptotic analyses. Our results indicated that cells after exposure to bufalin significantly decreased cell viability, and induced cell morphological changes and chromatin condensation in a concentration-dependent manner. Flow cytometric assays indicated that bufalin promoted ROS productions, loss of mitochondrial membrane potential (ΔΨm, intracellular Ca2+ release, and nitric oxide (NO formations in A375.S2 cells. Additionally, the apoptotic induction of bufalin on A375.S2 cells resulted from mitochondrial dysfunction-related responses (disruption of the ΔΨm and releases of cytochrome c, AIF, and Endo G, and activations of caspase-3, caspase-8 and caspase-9 expressions. Based on those observations, we suggest that bufalin-triggered apoptosis in A375.S2 cells is correlated with extrinsic- and mitochondria-mediated multiple signal pathways.

  11. Solar Radiation Alters Toxicity of Carbofuran: Evidence from Empirical Trials with Duttaphyrnus melanostictus

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    Full Text Available 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.e. mortality, growth and swimming activity. The mortality of tadpoles exposed to irradiated carbofuran was significantly lower than those exposed to the non-irradiated pesticide. Both treatment and control tadpoles showed a hormetic response for mortality. Tadpoles in irradiated tanks were also larger and more active than those in the control tanks. Photo-altered toxicity was evident at all three tested concentrations. The results of this study therefore signals caution when directly linking results of empirical trials to field scenarios and highlight the necessity to evaluate toxic effects of compounds under variable environmental conditions.

  12. Functional characterization and expression analysis of myoglobin in high-altitude lizard Phrynocephalus erythrurus. (United States)

    Xin, Ying; Tang, Xiaolong; Wang, Huihui; Lu, Songsong; Wang, Yan; Zhang, Yang; Chen, Qiang


    Myoglobin (Mb) is a monomeric hemoprotein which plays an important role in oxygen storage and transport in cardiac and skeletal muscle under hypoxia. The red tail toad-headed lizard Phrynocephalus erythrurus (Lacertilia: Agamidae), which inhabits at an elevation of 4500-5300 m on the Qinghai-Tibetan plateau, is known to be the highest living lizard in the world. To investigate the characters of myoglobin of this unique species, another low altitude lizard Phrynocephalus przewalskii (Lacertilia: Agamidae) was selected as a reference. The open reading frame (ORF) of myoglobin in two lizards was 465 bp which encodes a polypeptide of 154 amino acids with different theoretical molecular weight and isoelectric point. The amino acid substitutions of myoglobin between two species were found at Thr13Ile, Lys87Thr and His118Asn. Homology modeling results indicated that P. erythrurus myoglobin has a greater heme pocket, which may be more favorable to oxygen binding and unloading. On the other hand, the mRNA levels of myoglobin in both cardiac and skeletal muscle in P. erythrurus were significantly larger than those in low altitude P. przewalskii. At protein level, myoglobin concentration in skeletal muscle in P. erythrurus was notably increased, but no significant difference was observed in cardiac muscle.

  13. Tolperisone--a novel modulator of ionic currents in myelinated axons. (United States)

    Hinck, D; Koppenhöfer, E


    The actions of tolperisone on single intact Ranvier nodes of the toad Xenopus were investigated by means of the Hodgkin-Huxley formalism. Adding tolperisone to the bathing medium (100 micromol/l) caused the following fully reversible effects: 1. The sodium permeability P'Na was decreased by about 50% in a nearly potential-independent manner while the so-called sodium inactivation curve was shifted in the negative direction by about 3 mV. 2. The remaining parameters of the sodium system, i.e. m, taum and tauh, did not change. 3. The potassium permeability P'K decreased at strong depolarizing potentials (V > 60 mV); hence the permeability constant P(K) decreased by about 8%. However, weak depolarizations (V tolperisone cannot be said to have a so-called lidocaine-like activity, because its effect on potassium permeability in the threshold region is fundamentally different from that of other known local anaesthetics. We infer that this effect, in combination with the decrease in sodium permeability, is responsible for the tendency of tolperisone to reduce excitability and hence for the antispastic action of tolperisone documented by clinical observations.


    Institute of Scientific and Technical Information of China (English)

    尹检顺; 谭远辉


    The first excavation at Maituo, Wushan, which revealed 19 tombs, basically clarified the cultural characteristics of the Han tombs in the cemetery and preliminarily established the periodization criteria for these tombs. Among the 13 tombs uncovered in the present second excavation besides four Han tombs, there are newly discovered burial types that belong to the Warring States, Southern Dynasties and Song. They provided new data for further research into the cultural features of this graveyard in different periods. The achievements in the present excavation consist mainly in the following two aspects,The first is the discovery of three tombs belonging to the late Warring States period. They represent the Chu cultural complex in an area dominated by the Qin State. The second is the revelation of an Eastern Han high-rank tomb in a good condition (M47). The tomb contains over 100 funeral objects, including objects in gold, silver, bronze and lacquer that reflect the tomb owner's wealth, as well as rare treasures of art, such as exquisite glazed pottery tombfigurines of dancers, lamps with toad-shaped stands, and large-sized pottery, tomb guardians, animals, human figures and statues of the Western Queen Mother that are represented in various positions. The unearthed pottery models of buildings, such as those of theatres and watchtowers delicate in workmanship and clear in layout, are valuable to studying Han architecture. These finds provide precious data for systematically studying Han period production technology, culture and art, building style, religion, and burial customs.

  15. Evaluating the Quality of Protected Areas for Species: A Case Study in Ikh Nart Nature Reserve, Mongolia

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    James D. Murdoch


    Full Text Available Species’ distributions refl ect the quality of landscape conditions, and represent an important component of protected area management. However, distributions are diffi cult to estimate, and consequently, often determined through a combination of limited fi eld data and expert opinion, which may lead to biases. We demonstrate the use of occupancy models to map distributions and estimate landscape quality. We used occupancy models for two species, the red fox and toad-headed agama, to map their distributions in Ikh Nart Nature Reserve located in southeastern Mongolia. We then used occupancy probability as a measure of quality and tested whether differences existed in quality between three areas: 1 inside the reserve, 2 inside the reserve’s core protected area, and 3 outside the reserve, using 30 sample sites in each. Occupancy probability varied from 0.084 to 0.997 for red foxes and 0.022 to 0.949 for agamas in maps. Landscape quality was highest in the core area and lowest outside the reserve for red foxes, and highest outside the reserve and lowest in the core area for agamas. Our results provide visual depictions of distributions across the Ikh Nart landscape and a means of assessing the quality of the Ikh Nart protected area that may inform management activities.

  16. Relaxing the closure assumption in single-season occupancy models: staggered arrival and departure times (United States)

    Kendall, William L.; Hines, James E.; Nichols, James D.; Grant, Evan H. Campbell


    Occupancy statistical models that account for imperfect detection have proved very useful in several areas of ecology, including species distribution and spatial dynamics, disease ecology, and ecological responses to climate change. These models are based on the collection of multiple samples at each of a number of sites within a given season, during which it is assumed the species is either absent or present and available for detection while each sample is taken. However, for some species, individuals are only present or available for detection seasonally. We present a statistical model that relaxes the closure assumption within a season by permitting staggered entry and exit times for the species of interest at each site. Based on simulation, our open model eliminates bias in occupancy estimators and in some cases increases precision. The power to detect the violation of closure is high if detection probability is reasonably high. In addition to providing more robust estimation of occupancy, this model permits comparison of phenology across sites, species, or years, by modeling variation in arrival or departure probabilities. In a comparison of four species of amphibians in Maryland we found that two toad species arrived at breeding sites later in the season than a salamander and frog species, and departed from sites earlier.

  17. Yoginī e Streghe: luoghi isolati, animali selvatici, figure femminili di confine

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    Elisabetta Cangelosi


    Full Text Available In the folklore some female figures are related to border situations. Women, less relevant in the social and cultural context, can take a relevant role in the traditional, mythic and religious imagery. These figures are strictly linked to irrational and mystery. The analysis compares a group of tantric semi-deities, called Yogini, with witches: they are both confined in a border condition under the religious and social point of view since they are considered dangerous as well as respectful; they fly (sometimes after a metamorphosis in wild and dangerous birds like, they dance in circle, they turn into terrestrial animals (like snakes and toads they prefer isolated places and trees. They can live close to cemeteries but they can also be attracted by places where new born children are, in a sort of relation with both birth and death, the limits of human life. Following a comparison between these two groups that are very far away one from the other some interesting aspects appear: a major characteristic is their ambiguity. They are positive and negative at the same time, they are dangerous but attractive (being usually beautiful and sensual and even dangerous because so attractive. They are part of a wild  world which clash with a tidy and urbanized world: the first one is inhabited by demons which are not included in the official religious and cultural dimension; in the second one, which considers Yogini and witches as dangerous  entities, a rational and male-influenced approach prevails.

  18. The effects of ultraviolet-B radiation on the toxicity of fire-fighting chemicals (United States)

    Calfee, R.D.; Little, E.E.


    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.

  19. The European medicinal leech Hirudo medicinalis L.: Morphology and occurrence of an endangered species

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    U. Kutschera


    Full Text Available Although the European medicinal leech (Hirudo medicinalis L. 1758 is one of the best-known members of the Hirudinea due to its use in phlebotomy, this species has been confused with the Mediterranean taxon H. verbana Carena 1820. Here we describe the morphology of adult and juvenile H. medicinalis and document its genetic distance to H. verbana, using newly acquired mitochondrial DNA-sequence (cytochrome c oxidase subunit I, CO-I-data from specimens collected in Germany. Our CO-I analysis shows that H. medicinalis and H. verbana differ by 9.4 %. Hence, the original Hirudo-population diverged ca. 10 million years ago so that today two geographically separated biospecies exist that co-occur in only a few natural habitats. We analyzed the behaviour of adult H. medicinalis, but could not find differences with respect to its sister taxon H. verbana. Finally, we summarize the occurrence of H. medicinalis in Central Europe and conclude that this once widely distributed freshwater species largely disappeared in many countries. We suggest that the loss of natural freshwater ecosystems, with flat, warm banks, and amphibians (frogs, newts and toads as preferred host organisms for the juveniles, are largely responsible for the decline of H. medicinalis in Northern Europe.

  20. A Study of the Key Techniques of High-Speed Optical Time Division Multiplexing Systems

    Institute of Scientific and Technical Information of China (English)


    @@Several key techniques in high-speed optical time division multiplexing (OTDM) systems, including the generation and compression of gain-switched picosecond optical pulses, the all optical demultiplexer based on a nonlinear optical loop mirror (NOLM), terahertz optical asymmetric demultiplexer (TOAD) and the electroabsorption modulator in OTDM systems, are studied in this dissertation. The gain-switching characteristics and the nonlinear dynamics of a semiconductor laser are investigated by solving its single-mode rate equations numerically, highlighting the dependence of the pulse width and the peak power of a gain-switched pulse on the parameters such as the differential gain and the photon lifetime, and the effects of the DC bias current and the modulation current of the laser on the pulse width and the spectral width of the gain-switched pulse. The two-dimensional bifurcation diagram is computed in a large modulation current and modulation frequency range, and it is found that the low-frequency period doubling (multipling) and chaos region are not closed fully and outspread to the high modulation current direction with a narrow modulation frequency region. In addition, a new clock recovery scheme employing the period multipling is proposed. Besides compressing the gain-switched laser diode pulse can be compressed to 6.9ps by using this DILM compressor, and such a short pulse completely satisfies the requirement for a 40 Gbit/s optical time division multiplexing (OTDM) system.