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Sample records for intact amphibian skeletal

  1. Differential effects of sarcoplasmic reticular Ca(2+)-ATPase inhibition on charge movements and calcium transients in intact amphibian skeletal muscle fibres.

    PubMed

    Chawla, Sangeeta; Skepper, Jeremy N; Huang, Christopher L-H

    2002-03-15

    A hypothesis in which intramembrane charge reflects a voltage sensing process allosterically coupled to transitions in ryanodine receptor (RyR)-Ca(2+) release channels as opposed to one driven by release of intracellularly stored Ca(2+) would predict that such charging phenomena should persist in skeletal muscle fibres unable to release stored Ca(2+). Charge movement components were accordingly investigated in intact voltage-clamped amphibian fibres treated with known sarcoplasmic reticular (SR) Ca(2+)-ATPase inhibitors. Cyclopiazonic acid (CPA) pretreatment abolished Ca(2+) transients in fluo-3-loaded fibres following even prolonged applications of caffeine (10 mM) or K(+) (122 mM). Both CPA and thapsigargin (TG) transformed charge movements that included delayed (q(gamma)) "hump" components into simpler decays. However, steady-state charge-voltage characteristics were conserved to values (maximum charge, Q(max) approximately equal to 20-25 nC microF(-1); transition voltage, V* approximately equal to -40 to-50 mV; steepness factor, k approximately equal to 6-9 mV; holding voltage -90 mV) indicating persistent q(gamma) charge. The features of charge inactivation similarly suggested persistent q(beta) and q(gamma) charge contributions in CPA-treated fibres. Perchlorate (8.0 mM) restored the delayed kinetics shown by "on" q(gamma) charge movements, prolonged their "off" decays, conserved both Q(max) and k, yet failed to restore the capacity of such CPA-treated fibres for Ca(2+) release. Introduction of perchlorate (8.0 mM) or caffeine (0.2 mM) to tetracaine (2.0 mM)-treated fibres, also known to restore q(gamma) charge, similarly failed to restore Ca(2+) transients. Steady-state intramembrane q(gamma) charge thus persists with modified kinetics that can be restored to its normally complex waveform by perchlorate, even in intact muscle fibres unable to release Ca(2+). It is thus unlikely that q(gamma) charge movement is a consequence of SR Ca(2+) release rather than

  2. Amphibians.

    ERIC Educational Resources Information Center

    Naturescope, 1987

    1987-01-01

    Describes some of the characteristics of amphibians. Contains teaching activities ranging from a "frog sing-along" to lessons on amphibian adaptations, and night hikes to identify frog calls. Includes reproducible handouts to be used with the activities, and a quiz. (TW)

  3. Amphibian ryanodine receptor isoforms are related to those of mammalian skeletal or cardiac muscle.

    PubMed

    Lai, F A; Liu, Q Y; Xu, L; el-Hashem, A; Kramarcy, N R; Sealock, R; Meissner, G

    1992-08-01

    The ryanodine receptor (RyR)-Ca2+ release channels of frog skeletal muscle have been purified as 30S protein complexes comprised of two high molecular weight polypeptides. The upper and lower bands of the frog doublet comigrated on sodium dodecyl sulfate polyacylamide gels with the mammalian skeletal and cardiac RyR polypeptides, respectively. Immunoblot analysis showed that a polyclonal antiserum to the rat skeletal RyR preferentially cross-reacted with the upper band, whereas monoclonal antibodies to the canine cardiac RyR preferentially cross-reacted with the lower band of the frog receptor doublet. Immunoprecipitation studies indicated the presence of two homooligomer 30S RyR complexes comprised of either the lower or upper polypeptide band of the frog doublet, and immunocytochemical staining revealed their colocalization in frog gastrocnemius muscle. After planar lipid bilayer reconstitution of the 30S frog RyR, single-channel currents were observed that exhibited a Na+ and Ca2+ conductance and pharmacological characteristics similar to those of the mammalian skeletal and cardiac Ca2+ release channels. These results suggest that amphibian skeletal muscle expresses two distinct RyR isoforms that share epitopes in common with the mammalian skeletal or cardiac RyR. PMID:1325114

  4. Analysis of Aerobic Respiration in Intact Skeletal Muscle Tissue by Microplate-Based Respirometry.

    PubMed

    Shintaku, Jonathan; Guttridge, Denis C

    2016-01-01

    Mitochondrial function is a key component of skeletal muscle health, and its dysfunction has been associated with a wide variety of diseases. Microplate-based respirometry measures aerobic respiration of live cells through extracellular changes in oxygen concentration. Here, we describe a methodology to measure aerobic respiration of intact murine skeletal muscle tissue. The tissues are not cultured, permeabilized, or enzymatically dissociated to single fibers, so there is minimal experimental manipulation affecting the samples prior to acquiring measurements. PMID:27492183

  5. Characterization of actomyosin bond properties in intact skeletal muscle by force spectroscopy

    PubMed Central

    Colombini, Barbara; Bagni, M. Angela; Romano, Giovanni; Cecchi, Giovanni

    2007-01-01

    Force generation and motion in skeletal muscle result from interaction between actin and myosin myofilaments through the cyclical formation and rupture of the actomyosin bonds, the cross-bridges, in the overlap region of the sarcomeres. Actomyosin bond properties were investigated here in single intact muscle fibers by using dynamic force spectroscopy. The force needed to forcibly detach the cross-bridge ensemble in the half-sarcomere (hs) was measured in a range of stretching velocity between 3.4 × 103 nm·hs−1·s−1 or 3.3 fiber length per second (l0s−1) and 6.1 × 104 nm·hs−1·s−1 or 50 l0·s−1 during tetanic force development. The rupture force of the actomyosin bond increased linearly with the logarithm of the loading rate, in agreement with previous experiments on noncovalent single bond and with Bell theory [Bell GI (1978) Science 200:618–627]. The analysis permitted calculation of the actomyosin interaction length, xβ and the dissociation rate constant for zero external load, k0. Mean xβ was 1.25 nm, a value similar to that reported for single actomyosin bond under rigor condition. Mean k0 was 20 s−1, a value about twice as great as that reported in the literature for isometric force relaxation in the same type of muscle fibers. These experiments show, for the first time, that force spectroscopy can be used to reveal the properties of the individual cross-bridge in intact skeletal muscle fibers. PMID:17517641

  6. A Pilot Study of Ceramic Powder Far-Infrared Ray Irradiation (cFIR) on Physiology: Observation of Cell Cultures and Amphibian Skeletal Muscle.

    PubMed

    Leung, Ting-Kai; Lee, Chi-Ming; Tsai, Shih-Yin; Chen, Yi-Chien; Chao, Jo-Shui

    2011-08-31

    The purpose of this research was to assess the potential for far-infrared ray irradiation from ceramic powder to improve exercise performance at room temperature. We designed experiments with murine myoblast cells (C2C12) to study the effect of cFIR irradiation on cell viability and lactate dehydrogenase release under H2O2-mediated oxidative stress and evaluated intracellular levels of nitric oxide and calmodulin. We also used electro-stimulation of amphibian skeletal muscle. Our results show that cFIR strengthened C2C12 under oxidative stress and delayed onset of fatigue induced by muscle contractions. We discuss possible mechanisms including anti-oxidation and prevention of acid build-up in muscle tissue based, and expect to see more applications of cFIR in the future. PMID:22129823

  7. Amphibian Bioacoustics

    NASA Astrophysics Data System (ADS)

    Christensen-Dalsgaard, Jakob

    Anuran amphibians (frogs and toads) of most of the 3,500 species that exist today are highly vocal animals. In most frogs, males will spend considerable energy on calling and incur sizeable predation risks and the females’ detection and localization of the calls of conspecific males is often a prerequisite for successful mating. Therefore, acoustic communication is evidently evolutionarily important in the anurans, and their auditory system is probably shaped by the selective pressures associated with production, detection and localization of the communication calls.

  8. Acid tolerance in amphibians

    SciTech Connect

    Pierce, B.A.

    1985-04-01

    Studies of amphibian acid tolerance provide information about the potential effects of acid deposition on amphibian communities. Amphibians as a group appear to be relatively acid tolerant, with many species suffering increased mortality only below pH 4. However, amphibians exhibit much intraspecific variation in acid tolerance, and some species are sensitive to even low levels of acidity. Furthermore, nonlethal effects, including depression of growth rates and increases in developmental abnormalities, can occur at higher pH.

  9. Skeletal muscle intracellular pH and levels of high energy phosphates during hypercapnia in intact lizards by /sup 31/P NMR

    SciTech Connect

    Johnson, D.C.; Hitzig, B.M.; Elmden, K.; McFarland, E.; Koutcher, J.; Kazemi, H.

    1986-03-05

    Lizards have been shown to reduce ventilation during CO/sub 2/ breathing. This is thought to be detrimental to the maintenance of intracellular pH (pHi) and levels of high energy phosphates. The authors subjected chameleons (n=4) to 5% CO/sub 2/ breathing and made serial measurements of tail (skeletal) muscle pHi, levels of phosphocreatine (PCr), and ATP utilizing high resolution /sup 31/P NMR. pHi was unchanged from controls (7.27 +/- 0.06 units) (mean +/- SE) during 30 minutes of hypercapnia (7.19 +/- 0.09 units) (p>.2) demonstrating effective regulation of skeletal muscle pHi; however, there were significant decreases in the PCr/ATP ratios to 65% +/- 5% (p<.05) of control. The reduced PCr/ATP ratio does not appear due to decreased O/sub 2/ availability because there were no increases in the levels of glycolytic intermediates and inorganic phosphate which would indicate tissue hypoxia. It is possible that an active process requiring ATP is required for the maintenance of pHi in the presence of hypercapnia and that the reduction of PCr/ATP ratio is a reflection of an increased utilization of ATP.

  10. Surgery in Amphibians.

    PubMed

    Chai, Norin

    2016-01-01

    Amphibian surgery has been especially described in research. Since the last decade, interest for captive amphibians has increased, so have the indications for surgical intervention. Clinicians should not hesitate to advocate such manipulations. Amphibian surgeries have no overwhelming obstacles. These patients heal well and tolerate blood loss more than higher vertebrates. Most procedures described in reptiles (mostly lizards) can be undertaken in most amphibians if equipment can be matched to the patients' size. In general, the most difficult aspect would be the provision of adequate anesthesia. PMID:26611925

  11. Climate change and amphibians

    USGS Publications Warehouse

    Corn, P.S.

    2005-01-01

    Amphibian life histories are exceedingly sensitive to temperature and precipitation, and there is good evidence that recent climate change has already resulted in a shift to breeding earlier in the year for some species. There are also suggestions that the recent increase in the occurrence of El Niño events has caused declines of anurans in Central America and is linked to elevated mortality of amphibian embryos in the northwestern United States. However, evidence linking amphibian declines in Central America to climate relies solely on correlations, and the mechanisms underlying the declines are not understood. Connections between embryo mortality and declines in abundance have not been demonstrated. Analyses of existing data have generally failed to find a link between climate and amphibian declines. It is likely, however, that future climate change will cause further declines of some amphibian species. Reduced soil moisture could reduce prey species and eliminate habitat. Reduced snowfall and increased summer evaporation could have dramatic effects on the duration or occurrence of seasonal wetlands, which are primary habitat for many species of amphibians. Climate change may be a relatively minor cause of current amphibian declines, but it may be the biggest future challenge to the persistence of many species

  12. AMPHIBIAN POPULATION DYNAMICS

    EPA Science Inventory

    Agriculture has contributed to loss of vertebrate biodiversity in many regions, including the U.S. Corn Belt. Amphibian populations, in particular, have experienced widespread and often inexplicable declines, range reductions, and extinctions. However, few attempts have been made...

  13. Vikers Viking Amphibian - biplane

    NASA Technical Reports Server (NTRS)

    1924-01-01

    Vikers Viking Amphibian - biplane: Initially procured in 1921 by the U.S. Navy during their studies of foreign designs, the Vickers Viking IV became NACA 17 during its short period of study at Langley.

  14. Amphibian biology and husbandry.

    PubMed

    Pough, F Harvey

    2007-01-01

    Extant amphibians comprise three lineages-- salamanders (Urodela or Caudata), frogs and toads (Anura), and caecilians (Gymnophiona, Apoda, or Caecilia)--which contain more than 6,000 species. Fewer than a dozen species of amphibians are commonly maintained in laboratory colonies, and the husbandry requirements for the vast majority of amphibians are poorly known. For these species, a review of basic characteristics of amphibian biology supplemented by inferences drawn from the morphological and physiological characteristics of the species in question provides a basis for decisions about housing and feeding. Amphibians are ectotherms, and their skin is permeable to water, ions, and respiratory gases. Most species are secretive and, in many cases, nocturnal. The essential characteristics of their environment include appropriate levels of humidity, temperature, and lighting as well as retreat sites. Terrestrial and arboreal species require moist substrates, water dishes, and high relative humidity. Because temperature requirements for most species are poorly known, it is advisable to use a temperature mosaic that will allow an animal to find an appropriate temperature within its cage. Photoperiod may affect physiology and behavior (especially reproduction and hibernation), and although the importance of ultraviolet light for calcium metabolism by amphibians is not yet known, ecological observations suggest that it might be important for some species of frogs. Some amphibians are territorial, and some use olfactory cues to mark their territory and to recognize other individuals of their species. All amphibians are carnivorous as adults, and the feeding response of many species is elicited by the movement of prey. Diets should include a mixture of prey species, and it may be advisable to load prey with vitamins and minerals. PMID:17592184

  15. Adaptive colouration in amphibians.

    PubMed

    Rudh, Andreas; Qvarnström, Anna

    2013-01-01

    Amphibians, i.e. salamanders, frogs and caecilians show a wide range of bright colours in combination with contrasting patterns. There is variation among species, populations and also within species and populations. Furthermore, individuals often change colours during developmental stages or in response to environmental factors. This extraordinary variation means that there are excellent opportunities to test hypotheses of the adaptive significance of colours using amphibian species as models. We review the present view of functions of colouration in amphibians with the main focus on relatively unexplored topics. Variation in colouration has been found to play a role in thermoregulation, UV protection, predator avoidance and sexual signalling. However, many proposed cases of adaptive functions of colouration in amphibians remain virtually scientifically unexplored and surprisingly few genes influencing pigmentation or patterning have been detected. We would like to especially encourage more studies that take advantage of recent developments in measurement of visual properties of several possible signalling receivers (e.g. predators, competitors or mates). Future investigations on interactions between behaviour, ecology and vision have the potential to challenge our current view of the adaptive function of colouration in amphibians. PMID:23664831

  16. DEVELOPMENTAL DIVERSITY OF AMPHIBIANS

    PubMed Central

    Elinson, Richard P.; del Pino, Eugenia M.

    2011-01-01

    The current model amphibian, Xenopus laevis, develops rapidly in water to a tadpole which metamorphoses into a frog. Many amphibians deviate from the X. laevis developmental pattern. Among other adaptations, their embryos develop in foam nests on land or in pouches on their mother’s back or on a leaf guarded by a parent. The diversity of developmental patterns includes multinucleated oogenesis, lack of RNA localization, huge non-pigmented eggs, and asynchronous, irregular early cleavages. Variations in patterns of gastrulation highlight the modularity of this critical developmental period. Many species have eliminated the larva or tadpole and directly develop to the adult. The wealth of developmental diversity among amphibians coupled with the wealth of mechanistic information from X. laevis permit comparisons that provide deeper insights into developmental processes. PMID:22662314

  17. Hypometabolic homeostasis in overwintering aquatic amphibians.

    PubMed

    Boutilier, R G; Donohoe, P H; Tattersall, G J; West, T G

    1997-01-01

    Many amphibians encounter conditions each winter when their body temperature is so low that normal activities are suspended and the animals enter into a state of torpor. In ice-covered ponds or lakes, oxygen levels may also become limiting, thereby forcing animals to endure prolonged periods of severe hypoxia or anoxia. Certain frogs (e.g. Rana temporaria) can dramatically suppress their metabolism in anoxia but are not as tolerant as other facultative vertebrate anaerobes (e.g. turtle, goldfish) of prolonged periods of complete O2 lack. Many overwintering amphibians do, however, tolerate prolonged bouts of severe hypoxia, relying exclusively on cutaneous gas exchange. Rana temporaria overwintering for 2 months in hypoxic water (PO2 approximately 25 mmHg) at 3 degrees C progressively reduce their blood PCO2 to levels characteristic of water-breathing fish. The result is that blood pH rises and presumably facilitates transcutaneous O2 transfer by increasing Hb O2-affinity. Even after months of severe hypoxia, there is no substantial build-up of lactate as the animals continue to rely on cutaneous gas exchange to satisfy the requirements of a suppressed aerobic metabolism. Our recent experiments have shown that the skeletal muscle of frogs oxyconforms in vitro to the amount of O2 available. The cellular basis for the oxyconformation of skeletal muscle is unknown, but the hypothesis driving our continuing experiments theories that metabolic suppression at a cellular level is synonymous with suppressed ion leak across cellular membranes. PMID:9050248

  18. Amphibians of Olympic National Park

    USGS Publications Warehouse

    U.S. Geological Survey

    2000-01-01

    Amphibians evolved from fishes about 360 million years ago and were the first vertebrates adapted to life on land. The word amphibian means "double life." It refers to the life history of many amphibians, which spend part of their life in water and part on land. There are three major groups of amphibians: salamanders, frogs, and toads, and caecilians. Salamanders, frogs, and toads can be found in Olympic National Park (ONP), but caecilians live only in tropical regions. Many amphibians are generalist predators, eating almost any prey they can fit into their mouths.

  19. Rainforest: Reptiles and Amphibians

    ERIC Educational Resources Information Center

    Olson, Susanna

    2006-01-01

    Rainforest reptiles and amphibians are a vibrantly colored, multimedia art experience. To complete the entire project one may need to dedicate many class periods to production, yet in each aspect of the project a new and important skill, concept, or element is being taught or reinforced. This project incorporates the study of warm and cool color…

  20. Amphibian development in microgravity

    NASA Technical Reports Server (NTRS)

    Souza, K. A.

    1987-01-01

    The results of experiments performed by the U.S. Biosatellites 1 and 2 and the Gemini VIII and XII missions and by the Soviet Salyut and Soyuz missions on the effect of gravity on the development of prefertilized amphibian egg and, in particular, of the vestibular system of amphibian embryo are described. In these experiments, the condition of microgravity was reached only after the prefertilized eggs were in the early stages of first cell division or in the blastula stage. No significant changes were observed in the morphology of the embryos or in the vestibular system of embyos developed, respectively, for 2-5 days or 20 days under conditions of microgravity. Experiments planned for future spaceflights are discussed.

  1. Field Surveys of Amphibian Populations.

    ERIC Educational Resources Information Center

    Brodman, Robert

    2000-01-01

    Describes a course on amphibian research for environmental science majors. Involves students in field studies and introduces them to investigative research. Evaluates the course. (Contains 19 references.) (YDS)

  2. Chemosignals, hormones, and amphibian reproduction.

    PubMed

    Woodley, Sarah

    2015-02-01

    This article is part of a Special Issue "Chemosignals and Reproduction". Amphibians are often thought of as relatively simple animals especially when compared to mammals. Yet the chemosignaling systems used by amphibians are varied and complex. Amphibian chemosignals are particularly important in reproduction, in both aquatic and terrestrial environments. Chemosignaling is most evident in salamanders and newts, but increasing evidence indicates that chemical communication facilitates reproduction in frogs and toads as well. Reproductive hormones shape the production, dissemination, detection, and responsiveness to chemosignals. A large variety of chemosignals have been identified, ranging from simple, invariant chemosignals to complex, variable blends of chemosignals. Although some chemosignals elicit straightforward responses, others have relatively subtle effects. Review of amphibian chemosignaling reveals a number of issues to be resolved, including: 1) the significance of the complex, individually variable blends of courtship chemosignals found in some salamanders, 2) the behavioral and/or physiological functions of chemosignals found in anuran "breeding glands", 3) the ligands for amphibian V2Rs, especially V2Rs expressed in the main olfactory epithelium, and 4) the mechanism whereby transdermal delivery of chemosignals influences behavior. To date, only a handful of the more than 7000 species of amphibians has been examined. Further study of amphibians should provide additional insight to the role of chemosignals in reproduction. PMID:24945995

  3. DNA barcoding amphibians and reptiles.

    PubMed

    Vences, Miguel; Nagy, Zoltán T; Sonet, Gontran; Verheyen, Erik

    2012-01-01

    Only a few major research programs are currently targeting COI barcoding of amphibians and reptiles (including chelonians and crocodiles), two major groups of tetrapods. Amphibian and reptile species are typically old, strongly divergent, and contain deep conspecific lineages which might lead to problems in species assignment with incomplete reference databases. As far as known, there is no single pair of COI primers that will guarantee a sufficient rate of success across all amphibian and reptile taxa, or within major subclades of amphibians and reptiles, which means that the PCR amplification strategy needs to be adjusted depending on the specific research question. In general, many more amphibian and reptile taxa have been sequenced for 16S rDNA, which for some purposes may be a suitable complementary marker, at least until a more comprehensive COI reference database becomes available. DNA barcoding has successfully been used to identify amphibian larval stages (tadpoles) in species-rich tropical assemblages. Tissue sampling, DNA extraction, and amplification of COI is straightforward in amphibians and reptiles. Single primer pairs are likely to have a failure rate between 5 and 50% if taxa of a wide taxonomic range are targeted; in such cases the use of primer cocktails or subsequent hierarchical usage of different primer pairs is necessary. If the target group is taxonomically limited, many studies have followed a strategy of designing specific primers which then allow an easy and reliable amplification of all samples. PMID:22684953

  4. Alternative Conceptions in Animal Classification Focusing on Amphibians and Reptiles: A Cross-Age Study

    ERIC Educational Resources Information Center

    Yen, Chiung-Fen; Yao, Tsung-Wei; Chiu, Yu-Chih

    2004-01-01

    This study examined students' alternative conceptions of reptiles and amphibians and the extent to which these conceptions remain intact through the elementary (grades 4 and 6), junior, and senior high school years. We administered multiple-choice and free-response instruments to a total of 513 students and interviewed at least 20 students at each…

  5. Sex determination: the amphibian models.

    PubMed

    Eggert, Christophe

    2004-01-01

    We review and discuss current knowledge about sex determination in amphibians. The astonishing wide variety of mechanisms of genotypic sex determination is presented and discussed in an evolutionary context. We recall the natural occurrence of transitory juvenile hermaphroditism in some species. Our present knowledge of the mechanisms of sex determination in amphibians is compared to that in mammals. The influence of epigenetic factors, and especially temperature is highlighted. In amphibians, the influence of temperature on sexual differentiation, that can prevail over genotypic sex determination, remains poorly considered in publications. We suggest that studies on genetic and epigenetic factors of gonadal sex differentiation in amphibians could provide substantial information on the evolutionary process of sex determination mechanisms in current living vertebrates. PMID:15762298

  6. Polarity of the Amphibian Egg

    NASA Technical Reports Server (NTRS)

    Malacinski, G. M.

    1983-01-01

    Amphibian egg polarity and the mechanism which generates the polarity is addressed. Of particular concern is the question of whether the activation rotation which responds to gravity is a prerequisite for normal development.

  7. North American amphibians: distribution and diversity

    USGS Publications Warehouse

    : Green, David M., (Edited By); Weir, Linda A.; Casper, Gary S.; Lannoo, Michael

    2014-01-01

    Some 300 species of amphibians inhabit North America. The past two decades have seen an enormous growth in interest about amphibians and an increased intensity of scientific research into their fascinating biology and continent-wide distribution. This atlas presents the spectacular diversity of North American amphibians in a geographic context. It covers all formally recognized amphibian species found in the United States and Canada, many of which are endangered or threatened with extinction. Illustrated with maps and photos, the species accounts provide current information about distribution, habitat, and conservation. Researchers, professional herpetologists, and anyone intrigued by amphibians will value North American Amphibians as a guide and reference.

  8. BIOTIC FACTORS IN AMPHIBIAN POPULATION DECLINES

    EPA Science Inventory

    Amphibians evolved in, and continue to exist in, habitats that are replete with many other organisms. Some of these organisms serve as prey for amphibians and others interact with amphibians as predators, competitors, pathogens, or symbionts. Still other organisms in their enviro...

  9. Agricultural ponds support amphibian populations

    USGS Publications Warehouse

    Knutson, M.G.; Richardson, W.B.; Reineke, D.M.; Gray, B.R.; Parmelee, J.R.; Weick, S.E.

    2004-01-01

    In some agricultural regions, natural wetlands are scarce, and constructed agricultural ponds may represent important alternative breeding habitats for amphibians. Properly managed, these agricultural ponds may effectively increase the total amount of breeding habitat and help to sustain populations. We studied small, constructed agricultural ponds in southeastern Minnesota to assess their value as amphibian breeding sites. Our study examined habitat factors associated with amphibian reproduction at two spatial scales: the pond and the landscape surrounding the pond. We found that small agricultural ponds in southeastern Minnesota provided breeding habitat for at least 10 species of amphibians. Species richness and multispecies reproductive success were more closely associated with characteristics of the pond (water quality, vegetation, and predators) compared with characteristics of the surrounding landscape, but individual species were associated with both pond and landscape variables. Ponds surrounded by row crops had similar species richness and reproductive success compared with natural wetlands and ponds surrounded by nongrazed pasture. Ponds used for watering livestock had elevated concentrations of phosphorus, higher turbidity, and a trend toward reduced amphibian reproductive success. Species richness was highest in small ponds, ponds with lower total nitrogen concentrations, tiger salamanders (Ambystoma tigrinum) present, and lacking fish. Multispecies reproductive success was best in ponds with lower total nitrogen concentrations, less emergent vegetation, and lacking fish. Habitat factors associated with higher reproductive success varied among individual species. We conclude that small, constructed farm ponds, properly managed, may help sustain amphibian populations in landscapes where natural wetland habitat is rare. We recommend management actions such as limiting livestock access to the pond to improve water quality, reducing nitrogen input, and

  10. The Metamorphosis of Amphibian Toxicogenomics

    PubMed Central

    Helbing, Caren C.

    2012-01-01

    Amphibians are important vertebrates in toxicology often representing both aquatic and terrestrial forms within the life history of the same species. Of the thousands of species, only two have substantial genomics resources: the recently published genome of the Pipid, Xenopus (Silurana) tropicalis, and transcript information (and ongoing genome sequencing project) of Xenopus laevis. However, many more species representative of regional ecological niches and life strategies are used in toxicology worldwide. Since Xenopus species diverged from the most populous frog family, the Ranidae, ~200 million years ago, there are notable differences between them and the even more distant Caudates (salamanders) and Caecilians. These differences include genome size, gene composition, and extent of polyploidization. Application of toxicogenomics to amphibians requires the mobilization of resources and expertise to develop de novo sequence assemblies and analysis strategies for a broader range of amphibian species. The present mini-review will present the advances in toxicogenomics as pertains to amphibians with particular emphasis upon the development and use of genomic techniques (inclusive of transcriptomics, proteomics, and metabolomics) and the challenges inherent therein. PMID:22435070

  11. METAPOPULATION DYNAMICS AND AMPHIBIAN CONSERVATION

    EPA Science Inventory

    In many respects, amphibian spatial dynamics resemble classical metapopulation models, where subpopulations in breeding ponds blink in and out of existance and where extinction and colonization rates are functions of pond spatial arrangement. This "ponds-as-patches" view of amphi...

  12. Multiple overseas dispersal in amphibians.

    PubMed Central

    Vences, Miguel; Vieites, David R; Glaw, Frank; Brinkmann, Henner; Kosuch, Joachim; Veith, Michael; Meyer, Axel

    2003-01-01

    Amphibians are thought to be unable to disperse over ocean barriers because they do not tolerate the osmotic stress of salt water. Their distribution patterns have therefore generally been explained by vicariance biogeography. Here, we present compelling evidence for overseas dispersal of frogs in the Indian Ocean region based on the discovery of two endemic species on Mayotte. This island belongs to the Comoro archipelago, which is entirely volcanic and surrounded by sea depths of more than 3500 m. This constitutes the first observation of endemic amphibians on oceanic islands that did not have any past physical contact to other land masses. The two species of frogs had previously been thought to be nonendemic and introduced from Madagascar, but clearly represent new species based on their morphological and genetic differentiation. They belong to the genera Mantidactylus and Boophis in the family Mantellidae that is otherwise restricted to Madagascar, and are distinguished by morphology and mitochondrial and nuclear DNA sequences from mantellid species occurring in Madagascar. This discovery permits us to update and test molecular clocks for frogs distributed in this region. The new calibrations are in agreement with previous rate estimates and indicate two further Cenozoic transmarine dispersal events that had previously been interpreted as vicariance: hyperoliid frogs from Africa to Madagascar (Heterixalus) and from Madagascar to the Seychelles islands (Tachycnemis). Our results provide the strongest evidence so far that overseas dispersal of amphibians exists and is no rare exception, although vicariance certainly retains much of its importance in explaining amphibian biogeography. PMID:14667332

  13. Ecopathology of Ranaviruses Infecting Amphibians

    PubMed Central

    Miller, Debra; Gray, Matthew; Storfer, Andrew

    2011-01-01

    Ranaviruses are capable of infecting amphibians from at least 14 families and over 70 individual species. Ranaviruses infect multiple cell types, often culminating in organ necrosis and massive hemorrhaging. Subclinical infections have been documented, although their role in ranavirus persistence and emergence remains unclear. Water is an effective transmission medium for ranaviruses, and survival outside the host may be for significant duration. In aquatic communities, amphibians, reptiles and fish may serve as reservoirs. Controlled studies have shown that susceptibility to ranavirus infection and disease varies among amphibian species and developmental stages, and likely is impacted by host-pathogen coevolution, as well as, exogenous environmental factors. Field studies have demonstrated that the likelihood of epizootics is increased in areas of cattle grazing, where aquatic vegetation is sparse and water quality is poor. Translocation of infected amphibians through commercial trade (e.g., food, fish bait, pet industry) contributes to the spread of ranaviruses. Such introductions may be of particular concern, as several studies report that ranaviruses isolated from ranaculture, aquaculture, and bait facilities have greater virulence (i.e., ability to cause disease) than wild-type isolates. Future investigations should focus on the genetic basis for pathogen virulence and host susceptibility, ecological and anthropogenic mechanisms contributing to emergence, and vaccine development for use in captive populations and species reintroduction programs. PMID:22163349

  14. Ecotoxicology of Amphibians and Reptiles

    USGS Publications Warehouse

    2000-01-01

    For many years, ecological research on amphibians and reptiles has lagged behind that of other vertebrates such as fishes, birds, and mammals, despite the known importance of these animals in their environments. The lack of study has been particularly acute in the he area of ecotoxicology where the number of published scientific papers is a fraction of that found for the other vertebrate classes. Recently, scientists have become aware of severe crises among amphibian populations, including unexplained and sudden extinctions, worldwide declines, and hideous malformations. In many of these instances, contaminants have been listed as probable contributors. Data on the effects of contaminants on reptiles are so depauperate that even the most elementary interpretations are difficult. This state-of-the-science review and synthesis of amphibian and reptile ecotoxicology demonstrates the inter-relationships among distribution, ecology, physiology, and contaminant exposure, and interprets these topics as they pertain to comparative toxicity, population declines, malformations, and risk assessment . In this way, the book identifies and serves as a basis for the most pressing research needs in the coming years. The editors have invited 27 other internationally respected experts to examine the state of existing data in specific areas, interpret it in light of current problems, and identify research gaps and needs. Through its emphasis on recent research, extensive reviews and synthesis, Ecotoxicology of Amphibians and Reptiles will remain a definitive reference work well into the new century.

  15. The metamorphosis of amphibian toxicogenomics.

    PubMed

    Helbing, Caren C

    2012-01-01

    Amphibians are important vertebrates in toxicology often representing both aquatic and terrestrial forms within the life history of the same species. Of the thousands of species, only two have substantial genomics resources: the recently published genome of the Pipid, Xenopus (Silurana) tropicalis, and transcript information (and ongoing genome sequencing project) of Xenopus laevis. However, many more species representative of regional ecological niches and life strategies are used in toxicology worldwide. Since Xenopus species diverged from the most populous frog family, the Ranidae, ~200 million years ago, there are notable differences between them and the even more distant Caudates (salamanders) and Caecilians. These differences include genome size, gene composition, and extent of polyploidization. Application of toxicogenomics to amphibians requires the mobilization of resources and expertise to develop de novo sequence assemblies and analysis strategies for a broader range of amphibian species. The present mini-review will present the advances in toxicogenomics as pertains to amphibians with particular emphasis upon the development and use of genomic techniques (inclusive of transcriptomics, proteomics, and metabolomics) and the challenges inherent therein. PMID:22435070

  16. Skeletal radiology

    SciTech Connect

    Bowerman, J.W.

    1982-01-01

    The main emphasis of the chapter on skeletal radiology is CAT scanning and its use in the diagnosis of neoplasms. Other topics that are discussed include infections, arthritis, trauma, and metabolic and endocrine diseases as they relate to skeletal radiology. (KRM)

  17. Female Sexual Arousal in Amphibians

    PubMed Central

    Wilczynski, Walter; Lynch, Kathleen S.

    2010-01-01

    Rather than being a static, species specific trait, reproductive behavior in female amphibians is variable within an individual during the breeding season when females are capable of reproductive activity. Changes in receptivity coincide with changes in circulating estrogen. Estrogen is highest at the point when females are ready to choose a male and lay eggs. At this time female receptivity (her probability of responding to a male vocal signal) is highest and her selectivity among conspecific calls (measured by her probability of responding to a degraded or otherwise usually unattractive male signal) is lowest. These changes occur even though females retain the ability to discriminate different acoustic characteristics of various conspecific calls. After releasing her eggs, female amphibians quickly become less receptive and more choosy in terms of their responses to male sexual advertisement signals. Male vocal signals stimulate both behavior and estrogen changes in amphibian females making mating more probable. The changes in female reproductive behavior are the same as those generally accepted as indicative of a change in female sexual arousal leading to copulation. They are situationally triggered, gated by interactions with males, and decline with the consummation of sexual reproduction with a chosen male. The changes can be triggered by either internal physiological state or by the presence of stimuli presented by males, and the same stimuli change both behavior and physiological (endocrine) state in such a way as to make acceptance of a male more likely. Thus amphibian females demonstrate many of the same general characteristics of changing female sexual state that in mammals indicate sexual arousal. PMID:20816968

  18. Impending conservation crisis for Southeast Asian amphibians

    PubMed Central

    Rowley, Jodi; Brown, Rafe; Bain, Raoul; Kusrini, Mirza; Inger, Robert; Stuart, Bryan; Wogan, Guin; Thy, Neang; Chan-ard, Tanya; Trung, Cao Tien; Diesmos, Arvin; Iskandar, Djoko T.; Lau, Michael; Ming, Leong Tzi; Makchai, Sunchai; Truong, Nguyen Quang; Phimmachak, Somphouthone

    2010-01-01

    With an understudied amphibian fauna, the highest deforestation rate on the planet and high harvesting pressures, Southeast Asian amphibians are facing a conservation crisis. Owing to the overriding threat of habitat loss, the most critical conservation action required is the identification and strict protection of habitat assessed as having high amphibian species diversity and/or representing distinctive regional amphibian faunas. Long-term population monitoring, enhanced survey efforts, collection of basic biological and ecological information, continued taxonomic research and evaluation of the impact of commercial trade for food, medicine and pets are also needed. Strong involvement of regional stakeholders, students and professionals is essential to accomplish these actions. PMID:20007165

  19. AMPHIBIANS AS BIOINDICATORS OF WETLAND CONDITION

    EPA Science Inventory

    King county has over ten years of data on the distribution and abundance of amphibians in wetlands. Changes in wetland amphibian composition are being analyzed in relationship to physical changes within wetlands and surrounding land-use development and change. In addition to tes...

  20. (Photosynthesis in intact plants)

    SciTech Connect

    Not Available

    1990-01-01

    Progress in the two years since the last renewal application has been excellent. We have made substantial contributions on both main fronts of the projects, and are particularly happy with the progress of our research on intact plants. The approach of basing our field work on a sound foundation of laboratory studies has enabled is to use methods which provide unambiguous assays of well characterized reactions. We have also made excellent progress in several laboratory studies which will have direct applications in future field work, and have introduced to the laboratory a range of molecular genetics techniques which will allow us to explore new options in the attempt to understand function at the level of molecular structure.

  1. Fire and amphibians in North America

    USGS Publications Warehouse

    Pilliod, D.S.; Bury, R.B.; Hyde, E.J.; Pearl, C.A.; Corn, P.S.

    2003-01-01

    Information on amphibian responses to fire and fuel reduction practices is critically needed due to potential declines of species and the prevalence of new, more intensive fire management practices in North American forests. The goals of this review are to summarize the known and potential effects of fire and fuels management on amphibians and their aquatic habitats, and to identify information gaps to help direct future scientific research. Amphibians as a group are taxonomically and ecologically diverse; in turn, responses to fire and associated habitat alteration are expected to vary widely among species and among geographic regions. Available data suggest that amphibian responses to fire are spatially and temporally variable and incompletely understood. Much of the limited research has addressed short-term (1-3 years) effects of prescribed fire on terrestrial life stages of amphibians in the southeastern United States. Information on the long-term negative effects of fire on amphibians and the importance of fire for maintaining amphibian communities is sparse for the majority of taxa in North America. Given the size and severity of recent wildland fires and the national effort to reduce fuels on federal lands, future studies are needed to examine the effects of these landscape disturbances on amphibians. We encourage studies to address population-level responses of amphibians to fire by examining how different life stages are affected by changes in aquatic, riparian, and upland habitats. Research designs need to be credible and provide information that is relevant for fire managers and those responsible for assessing the potential effects of various fuel reduction alternatives on rare, sensitive, and endangered amphibian species. ?? 2003 Elsevier Science B.V. All rights reserved.

  2. Ecology and pathology of amphibian ranaviruses.

    PubMed

    Gray, Matthew J; Miller, Debra L; Hoverman, Jason T

    2009-12-01

    Mass mortality of amphibians has occurred globally since at least the early 1990s from viral pathogens that are members of the genus Ranavirus, family Iridoviridae. The pathogen infects multiple amphibian hosts, larval and adult cohorts, and may persist in herpetofaunal and osteichthyan reservoirs. Environmental persistence of ranavirus virions outside a host may be several weeks or longer in aquatic systems. Transmission occurs by indirect and direct routes, and includes exposure to contaminated water or soil, casual or direct contact with infected individuals, and ingestion of infected tissue during predation, cannibalism, or necrophagy. Some gross lesions include swelling of the limbs or body, erythema, swollen friable livers, and hemorrhage. Susceptible amphibians usually die from chronic cell death in multiple organs, which can occur within a few days following infection or may take several weeks. Amphibian species differ in their susceptibility to ranaviruses, which may be related to their co-evolutionary history with the pathogen. The occurrence of recent widespread amphibian population die-offs from ranaviruses may be an interaction of suppressed and naïve host immunity, anthropogenic stressors, and novel strain introduction. This review summarizes the ecological research on amphibian ranaviruses, discusses possible drivers of emergence and conservation strategies, and presents ideas for future research directions. We also discuss common pathological signs of ranaviral disease, methods for diagnostic evaluation, and ranavirus surveillance methods. In as much as ranaviral disease is listed as a notifiable disease by the World Organization for Animal Health and is a threat to amphibian survival, we recommend that biosecurity precautions are implemented by nations to reduce the likelihood of transporting ranavirus virions among populations. Biosecurity precautions include disinfecting footwear and equipment that comes in contact with surface water inhabited

  3. Two-stage recovery of amphibian assemblages following selective logging of tropical forests.

    PubMed

    Adum, Gilbert Baase; Eichhorn, Markus Peter; Oduro, William; Ofori-Boateng, Caleb; Rödel, Mark-Oliver

    2013-04-01

    There is a lack of quantitative information on the effectiveness of selective-logging practices in ameliorating effects of logging on faunal communities. We conducted a large-scale replicated field study in 3 selectively logged moist semideciduous forests in West Africa at varying times after timber extraction to assess post logging effects on amphibian assemblages. Specifically, we assessed whether the diversity, abundance, and assemblage composition of amphibians changed over time for forest-dependent species and those tolerant of forest disturbance. In 2009, we sampled amphibians in 3 forests (total of 48 study plots, each 2 ha) in southwestern Ghana. In each forest, we established plots in undisturbed forest, recently logged forest, and forest logged 10 and 20 years previously. Logging intensity was constant across sites with 3 trees/ha removed. Recently logged forests supported substantially more species than unlogged forests. This was due to an influx of disturbance-tolerant species after logging. Simultaneously Simpson's index decreased, with increased in dominance of a few species. As time since logging increased richness of disturbance-tolerant species decreased until 10 years after logging when their composition was indistinguishable from unlogged forests. Simpson's index increased with time since logging and was indistinguishable from unlogged forest 20 years after logging. Forest specialists decreased after logging and recovered slowly. However, after 20 years amphibian assemblages had returned to a state indistinguishable from that of undisturbed forest in both abundance and composition. These results demonstrate that even with low-intensity logging (≤3 trees/ha) a minimum 20-year rotation of logging is required for effective conservation of amphibian assemblages in moist semideciduous forests. Furthermore, remnant patches of intact forests retained in the landscape and the presence of permanent brooks may aid in the effective recovery of amphibian

  4. Radioautographic investigation of retinal growth in mature amphibians

    SciTech Connect

    Svistunov, S.A.; Mitashov, V.I.

    1986-07-01

    Growth of the retina was studied in mature intact amphibians, tritons, axolotls, ambystomas and clawed frogs, for six months using multiple injection of /sup 3/H-thymidine. It was established that the source of replenishment of the retina by new cells is its terminal zone in all animals investigated. This is attested to by the gradual migration of labeled cells from the growth zone into differentiated layers of the retina. The most intensely labeled cells occupy a distal position relative to other labeled cells, therefore marking the boundary between the initial part of the retina, not containing labeled nuclei, and the part being augmented. For each species studied, a level of proliferative activity is characteristic for cells of the terminal zone, which decreases in the order axolotl-clawed frog-triton -ambystoma. In the axolotl and additional growth zone is noted in the retina, in addition to the terminal, which is located in the area of the unclosed section of the embryonic fissure. Results obtained serve as a basis for the regenerative potentials of eye tissues revealed previously in these amphibian species.

  5. Skeletal dysplasias.

    PubMed

    Krakow, Deborah

    2015-06-01

    The skeletal dysplasias are a group of more than 450 heritable disorders of bone. They frequently present in the newborn period with disproportion, radiographic abnormalities, and occasionally other organ system abnormalities. For improved clinical care, it is important to determine a precise diagnosis to aid in management, familial recurrence, and identify those disorders highly associated with mortality. Long-term management of these disorders is predicated on an understanding of the associated skeletal system abnormalities, and these children are best served by a team approach to health care surveillance. PMID:26042906

  6. Skeletal Dysplasias

    PubMed Central

    Krakow, Deborah

    2015-01-01

    Synoposis The skeletal dysplasias are a group of more than 450 heritable disorders of bone. They frequently present in the newborn period with disproportion, radiographic abnormalities, and occasionally other organ system abnormalities. For improved clinical care it is important to determine a precise diagnosis to aid in management, familial recurrence and identify those disorders highly associated with mortality. Long-term management of these disorders is predicated on an understanding of the associated skeletal system abnormalities and these children are best served by a team approach to health care surveillance. PMID:26042906

  7. First evidence of amphibian chytrid fungus (Batrachochytrium dendrobatidis) and ranavirus in Hong Kong amphibian trade.

    PubMed

    Kolby, Jonathan E; Smith, Kristine M; Berger, Lee; Karesh, William B; Preston, Asa; Pessier, Allan P; Skerratt, Lee F

    2014-01-01

    The emerging infectious amphibian diseases caused by amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranaviruses are responsible for global amphibian population declines and extinctions. Although likely to have been spread by a variety of activities, transcontinental dispersal appears closely associated with the international trade in live amphibians. The territory of Hong Kong reports frequent, high volume trade in amphibians, and yet the presence of Bd and ranavirus have not previously been detected in either traded or free-ranging amphibians. In 2012, a prospective surveillance project was conducted to investigate the presence of these pathogens in commercial shipments of live amphibians exported from Hong Kong International Airport. Analysis of skin (Bd) and cloacal (ranavirus) swabs by quantitative PCR detected pathogen presence in 31/265 (11.7%) and in 105/185 (56.8%) of amphibians, respectively. In addition, the water in which animals were transported tested positive for Bd, demonstrating the risk of pathogen pollution by the disposal of untreated wastewater. It is uncertain whether Bd and ranavirus remain contained within Hong Kong's trade sector, or if native amphibians have already been exposed. Rapid response efforts are now urgently needed to determine current pathogen distribution in Hong Kong, evaluate potential trade-associated exposure to free-ranging amphibians, and identify opportunities to prevent disease establishment. PMID:24599268

  8. First Evidence of Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) and Ranavirus in Hong Kong Amphibian Trade

    PubMed Central

    Kolby, Jonathan E.; Smith, Kristine M.; Berger, Lee; Karesh, William B; Preston, Asa; Pessier, Allan P.; Skerratt, Lee F.

    2014-01-01

    The emerging infectious amphibian diseases caused by amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranaviruses are responsible for global amphibian population declines and extinctions. Although likely to have been spread by a variety of activities, transcontinental dispersal appears closely associated with the international trade in live amphibians. The territory of Hong Kong reports frequent, high volume trade in amphibians, and yet the presence of Bd and ranavirus have not previously been detected in either traded or free-ranging amphibians. In 2012, a prospective surveillance project was conducted to investigate the presence of these pathogens in commercial shipments of live amphibians exported from Hong Kong International Airport. Analysis of skin (Bd) and cloacal (ranavirus) swabs by quantitative PCR detected pathogen presence in 31/265 (11.7%) and in 105/185 (56.8%) of amphibians, respectively. In addition, the water in which animals were transported tested positive for Bd, demonstrating the risk of pathogen pollution by the disposal of untreated wastewater. It is uncertain whether Bd and ranavirus remain contained within Hong Kong’s trade sector, or if native amphibians have already been exposed. Rapid response efforts are now urgently needed to determine current pathogen distribution in Hong Kong, evaluate potential trade-associated exposure to free-ranging amphibians, and identify opportunities to prevent disease establishment. PMID:24599268

  9. NUDC expression during amphibian development.

    PubMed

    Moreau, N; Aumais, J P; Prudhomme, C; Morris, S M; Yu-Lee, L Y

    2001-10-01

    To identify gene products important for gastrulation in the amphibian Pleurodeles waltl, a screen for regional differences in new protein expression at the early gastrula stage was performed. A 45 kDa protein whose synthesis was specific for progenitor endodermal cells was identified. Microsequencing and cDNA cloning showed that P45 is highly homologous to rat NUDC, a protein suggested to play a role in nuclear migration. Although PNUDC can be detected in all regions of the embryo, its de novo synthesis is tightly regulated spatially and temporally throughout oogenesis and embryonic development. New PNUDC synthesis in the progenitor endodermal cells depends on induction by the mesodermal cells in the gastrula. During development, PNUDC is localized in the egg cortical cytoplasm, at the cleavage furrow during the first embryonic division, around the nuclei and cortical regions of bottle cells in the gastrula, and at the basal region of polarized tissues in the developing embryo. These results show for the first time the expression and compartmentalization of PNUDC at distinct stages during amphibian development. PMID:11732844

  10. Sperm storage in caecilian amphibians

    PubMed Central

    2012-01-01

    Background Female sperm storage has evolved independently multiple times among vertebrates to control reproduction in response to the environment. In internally fertilising amphibians, female salamanders store sperm in cloacal spermathecae, whereas among anurans sperm storage in oviducts is known only in tailed frogs. Facilitated through extensive field sampling following historical observations we tested for sperm storing structures in the female urogenital tract of fossorial, tropical caecilian amphibians. Findings In the oviparous Ichthyophis cf. kohtaoensis, aggregated sperm were present in a distinct region of the posterior oviduct but not in the cloaca in six out of seven vitellogenic females prior to oviposition. Spermatozoa were found most abundantly between the mucosal folds. In relation to the reproductive status decreased amounts of sperm were present in gravid females compared to pre-ovulatory females. Sperm were absent in females past oviposition. Conclusions Our findings indicate short-term oviductal sperm storage in the oviparous Ichthyophis cf. kohtaoensis. We assume that in female caecilians exhibiting high levels of parental investment sperm storage has evolved in order to optimally coordinate reproductive events and to increase fitness. PMID:22672478

  11. The physics of intact capture

    NASA Technical Reports Server (NTRS)

    Tsou, Peter; Griffiths, D. J.; Albee, A. L.

    1994-01-01

    The ability to capture projectiles intact at hypervelocities in underdense media open a new area of study in physics. Underdense material behaves markedly different than solid, liquid, or gas upon hypervelocity impact. This new phenomenon enables applications in science that would either not be possible or would be very costly by other means. This phenomenon has been fully demonstrated in the laboratory and validated in space. Even more interesting is the fact that this hypervelocity intact capture was accomplished passively. A better understanding of the physics of intact capture will lead to improvements in intact capture. A collection of physical observations of this phenomenon is presented here.

  12. Nutrition and health in amphibian husbandry.

    PubMed

    Ferrie, Gina M; Alford, Vance C; Atkinson, Jim; Baitchman, Eric; Barber, Diane; Blaner, William S; Crawshaw, Graham; Daneault, Andy; Dierenfeld, Ellen; Finke, Mark; Fleming, Greg; Gagliardo, Ron; Hoffman, Eric A; Karasov, William; Klasing, Kirk; Koutsos, Elizabeth; Lankton, Julia; Lavin, Shana R; Lentini, Andrew; Livingston, Shannon; Lock, Brad; Mason, Tom; McComb, Alejandra; Morris, Cheryl; Pessier, Allan P; Olea-Popelka, Francisco; Probst, Tom; Rodriguez, Carlos; Schad, Kristine; Semmen, Kent; Sincage, Jamie; Stamper, M Andrew; Steinmetz, Jason; Sullivan, Kathleen; Terrell, Scott; Wertan, Nina; Wheaton, Catharine J; Wilson, Brad; Valdes, Eduardo V

    2014-01-01

    Amphibian biology is intricate, and there are many inter-related factors that need to be understood before establishing successful Conservation Breeding Programs (CBPs). Nutritional needs of amphibians are highly integrated with disease and their husbandry needs, and the diversity of developmental stages, natural habitats, and feeding strategies result in many different recommendations for proper care and feeding. This review identifies several areas where there is substantial room for improvement in maintaining healthy ex situ amphibian populations specifically in the areas of obtaining and utilizing natural history data for both amphibians and their dietary items, achieving more appropriate environmental parameters, understanding stress and hormone production, and promoting better physical and population health. Using a scientific or research framework to answer questions about disease, nutrition, husbandry, genetics, and endocrinology of ex situ amphibians will improve specialists' understanding of the needs of these species. In general, there is a lack of baseline data and comparative information for most basic aspects of amphibian biology as well as standardized laboratory approaches. Instituting a formalized research approach in multiple scientific disciplines will be beneficial not only to the management of current ex situ populations, but also in moving forward with future conservation and reintroduction projects. This overview of gaps in knowledge concerning ex situ amphibian care should serve as a foundation for much needed future research in these areas. PMID:25296396

  13. Nutrition and Health in Amphibian Husbandry

    PubMed Central

    Ferrie, Gina M.; Alford, Vance C.; Atkinson, Jim; Baitchman, Eric; Barber, Diane; Blaner, William S.; Crawshaw, Graham; Daneault, Andy; Dierenfeld, Ellen; Finke, Mark; Fleming, Greg; Gagliardo, Ron; Hoffman, Eric A.; Karasov, William; Klasing, Kirk; Koutsos, Elizabeth; Lankton, Julia; Lavin, Shana R.; Lentini, Andrew; Livingston, Shannon; Lock, Brad; Mason, Tom; McComb, Alejandra; Morris, Cheryl; Pessier, Allan P.; Olea-Popelka, Francisco; Probst, Tom; Rodriguez, Carlos; Schad, Kristine; Semmen, Kent; Sincage, Jamie; Stamper, M. Andrew; Steinmetz, Jason; Sullivan, Kathleen; Terrell, Scott; Wertan, Nina; Wheaton, Catharine J.; Wilson, Brad; Valdes, Eduardo V.

    2015-01-01

    Amphibian biology is intricate, and there are many inter-related factors that need to be understood before establishing successful Conservation Breeding Programs (CBPs). Nutritional needs of amphibians are highly integrated with disease and their husbandry needs, and the diversity of developmental stages, natural habitats, and feeding strategies result in many different recommendations for proper care and feeding. This review identifies several areas where there is substantial room for improvement in maintaining healthy ex situ amphibian populations specifically in the areas of obtaining and utilizing natural history data for both amphibians and their dietary items, achieving more appropriate environmental parameters, understanding stress and hormone production, and promoting better physical and population health. Using a scientific or research framework to answer questions about disease, nutrition, husbandry, genetics, and endocrinology of ex situ amphibians will improve specialists’ understanding of the needs of these species. In general, there is a lack of baseline data and comparative information for most basic aspects of amphibian biology as well as standardized laboratory approaches. Instituting a formalized research approach in multiple scientific disciplines will be beneficial not only to the management of current ex situ populations, but also in moving forward with future conservation and reintroduction projects. This overview of gaps in knowledge concerning ex situ amphibian care should serve as a foundation for much needed future research in these areas. PMID:25296396

  14. Suitability of amphibians and reptiles for translocation.

    PubMed

    Germano, Jennifer M; Bishop, Phillip J

    2009-02-01

    Translocations are important tools in the field of conservation. Despite increased use over the last few decades, the appropriateness of translocations for amphibians and reptiles has been debated widely over the past 20 years. To provide a comprehensive evaluation of the suitability of amphibians and reptiles for translocation, we reviewed the results of amphibian and reptile translocation projects published between 1991 and 2006. The success rate of amphibian and reptile translocations reported over this period was twice that reported in an earlier review in 1991. Success and failure rates were independent of the taxonomic class (Amphibia or Reptilia) released. Reptile translocations driven by human-wildlife conflict mitigation had a higher failure rate than those motivated by conservation, and more recent projects of reptile translocations had unknown outcomes. The outcomes of amphibian translocations were significantly related to the number of animals released, with projects releasing over 1000 individuals being most successful. The most common reported causes of translocation failure were homing and migration of introduced individuals out of release sites and poor habitat. The increased success of amphibian and reptile translocations reviewed in this study compared with the 1991 review is encouraging for future conservation projects. Nevertheless, more preparation, monitoring, reporting of results, and experimental testing of techniques and reintroduction questions need to occur to improve translocations of amphibians and reptiles as a whole. PMID:19143783

  15. Skeletal muscle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are approximately 650-850 muscles in the human body these include skeletal (striated), smooth and cardiac muscle. The approximation is based on what some anatomists consider separate muscle or muscle systems. Muscles are classified based on their anatomy (striated vs. smooth) and if they are v...

  16. Leaping forward in amphibian health and nutrition.

    PubMed

    Olea-Popelka, Francisco; Ferrie, Gina M; Morris, Cheryl; Pessier, Allan P; Schad, Kristine; Stamper, M Andrew; Gagliardo, Ron; Koutsos, Elizabeth; Valdes, Eduardo V

    2014-01-01

    The Epidemiology Working Group, a subgroup of the participants of the Disney's Animal Kingdom Workshop on "Ex situ Amphibian Medicine and Nutrition," identified a critical need to design and implement approaches that will facilitate the assessment and evaluation of factors impacting amphibian health. In this manuscript, we describe and summarize the outcomes of this workshop with regards (a) the identified gaps in knowledge, (b) identified priorities for closing these gaps, and (c) compile a list of actions to address these priorities. Four general areas of improvement were identified in relation to how measurements are currently being taken to evaluate ex situ amphibian health: nutrition, infectious diseases, husbandry, and integrated biology including genetics and endocrinology. The proposed actions that will be taken in order to address the identified gaps include: (1) identify and quantify major health issues affecting ex situ amphibian populations, (2) identify and coordinate laboratories to conduct analyses using standardized and validated protocols to measure nutritional, infectious diseases, genetic, and hormonal parameters, (3) determine in situ baseline distribution of parameters related to amphibian health, and (4) establish an inter-disciplinary research approach to target specific hypotheses related to amphibian health such as the effects of population genetics (e.g., relatedness, inbreeding) on disease susceptibility, or how environmental parameters are related to chronic stress and hormone production. We think is important to address current gaps in knowledge regarding amphibian health in order to increase the probability to succeed in addressing the issues faced by in situ and ex situ amphibians populations. We are confident that the recommendations provided in this manuscript will facilitate to address these challenges and could have a positive impact in both the health of in situ and ex situ amphibian populations, worldwide. PMID:25279727

  17. [Perspective on gravitational biology of amphibians].

    PubMed

    Yamashita, Masamichi; Naitoh, Tomio; Wassersug, Richard J

    2002-12-01

    We review here the scientific significance of the use of amphibians for research in gravitational biology. Since amphibian eggs are quite large, yet develop rapidly and externally, it is easy to observe their development. Consequently amphibians were the first vertebrates to have their early developmental processes investigated in space. Though several deviations from normal embryonic development occur when amphibians are raised in microgravity, their developmental program is robust enough to return the organisms to an ostensibly normal morphology by the time they hatch. Evolutionally, amphibians were the first vertebrate animal to come out of the water and onto land. Subsequently they diversified and have adaptively radiated to various habitats. They now inhabit aquatic, terrestrial, arboreal and fossorial niches. This diversity can be used to help study the biological effects of gravity at the organismal level, where macroscopic phenomena are associated with gravitational loading. By choosing different amphibian models and using a comparative approach one can effectively identify the action of gravity on biological systems, and the adaptation that vertebrates have made to this loading. Advances in cellular and molecular biology provide powerful tools for the study in many fields, including gravitational biology, and amphibians have proven to be good models for studies at those levels as well. The low metabolic rates of amphibians make them convenient organisms to work with (compared to birds and mammals) in the difficult and confined spaces on orbiting research platforms. We include here a review of what is known about and the potential for further behavioral and physiological researches in space using amphibians. PMID:12721528

  18. Ecotoxicology of organic contaminants to amphibians

    USGS Publications Warehouse

    Sparling, D.W.

    2000-01-01

    The effects of organic contaminants on amphibians are poorly known but of considerable interest. These contaminants include the highly toxic dioxins and furans as well as PCBs, PAHs and organochlorine pesticides. Although these compounds may have lower acute toxicity than dioxins and furans, they have been implicated in several problems associated with genotoxicity, endocrine disruption, malformations and reduced growth. There is evidence that amphibian tadpoles bioaccumulate these organic compounds and may have biological concentrating factors ranging in the hundreds. This chapter reviews what is known about the effects and concentrations of organic contaminants in amphibians and provides recommendations for further research

  19. Cardiovascular physiology and diseases of amphibians.

    PubMed

    Heinz-Taheny, Kathleen M

    2009-01-01

    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. PMID:19131029

  20. Report of Amphibian Development Group

    NASA Technical Reports Server (NTRS)

    Malacinski, G.

    1985-01-01

    Amphibian and fish embryos are extremely well suited for studies on pattern specification, whereas other systems (e.g., avian or mammalian) might be just as well suited for studies on differentiation or growth. Those distinctions are important for at least two reasons: (1) More precise focus regarding underlying mechanisms is called for when those distinctions are made. That facilitates the formulation of specific models or hypotheses; and (2) stress effects (i.e., the effects of weightlessness on structures (e.g., bones) which normally bear a load) are distinguished as being indirect, in contrast to direct effects of microgravity, which would be expected to act on pattern specification. That is, direct gravity effects are distinguished from indirect stress effects.

  1. Space research with intact organisms

    NASA Technical Reports Server (NTRS)

    Phillips, Robert W.; Haddy, Francis J.

    1992-01-01

    Effects of space exposure on intact organisms are briefly reviewed, and examples of future experiments that might provide new information on the role of gravity in the evolution of life are suggested. It is noted that long term experiments with intact plant and animals for studying gravitational thresholds will provide important new insights.

  2. Amphibian responses to photoinduced toxicity of PAHs

    SciTech Connect

    Hatch, A.C.; Burton, G.A. Jr.

    1995-12-31

    Amphibians are essential components of many ecosystems, yet little information exists on their sensitivity to environmental stressors. Recent evidence shows amphibian diversity is declining. Others have suggested this decline is a result of increasing ultraviolet (UV) light levels. Polycyclic aromatic hydrocarbons (PAHs) are widespread pollutants in the aquatic environment and their toxicity is increased in the presence of UV light. Embryos of two frogs (Rana pipiens and Xenopus laevis) were exposed to a PAH, fluoranthene, to evaluate amphibian responses to this common contaminant in the presence of sunlight. Hatching rate and development were measured in field and laboratory exposures at multiple concentrations and varying UV intensities. Hatching rate was relatively unaffected, while newly hatched larvae were sensitive to low (ug/L) concentrations. Response was related to both PAH concentration and UV intensity. Results suggest that PAH contamination in the aquatic environment may contribute to declines in amphibian populations.

  3. Amphibian macrophage development and antiviral defenses.

    PubMed

    Grayfer, Leon; Robert, Jacques

    2016-05-01

    Macrophage lineage cells represent the cornerstone of vertebrate physiology and immune defenses. In turn, comparative studies using non-mammalian animal models have revealed that evolutionarily distinct species have adopted diverse molecular and physiological strategies for controlling macrophage development and functions. Notably, amphibian species present a rich array of physiological and environmental adaptations, not to mention the peculiarity of metamorphosis from larval to adult stages of development, involving drastic transformation and differentiation of multiple new tissues. Thus it is not surprising that different amphibian species and their respective tadpole and adult stages have adopted unique hematopoietic strategies. Accordingly and in order to establish a more comprehensive view of these processes, here we review the hematopoietic and monopoietic strategies observed across amphibians, describe the present understanding of the molecular mechanisms driving amphibian, an in particular Xenopus laevis macrophage development and functional polarization, and discuss the roles of macrophage-lineage cells during ranavirus infections. PMID:26705159

  4. A unified anatomy ontology of the vertebrate skeletal system.

    PubMed

    Dahdul, Wasila M; Balhoff, James P; Blackburn, David C; Diehl, Alexander D; Haendel, Melissa A; Hall, Brian K; Lapp, Hilmar; Lundberg, John G; Mungall, Christopher J; Ringwald, Martin; Segerdell, Erik; Van Slyke, Ceri E; Vickaryous, Matthew K; Westerfield, Monte; Mabee, Paula M

    2012-01-01

    The skeleton is of fundamental importance in research in comparative vertebrate morphology, paleontology, biomechanics, developmental biology, and systematics. Motivated by research questions that require computational access to and comparative reasoning across the diverse skeletal phenotypes of vertebrates, we developed a module of anatomical concepts for the skeletal system, the Vertebrate Skeletal Anatomy Ontology (VSAO), to accommodate and unify the existing skeletal terminologies for the species-specific (mouse, the frog Xenopus, zebrafish) and multispecies (teleost, amphibian) vertebrate anatomy ontologies. Previous differences between these terminologies prevented even simple queries across databases pertaining to vertebrate morphology. This module of upper-level and specific skeletal terms currently includes 223 defined terms and 179 synonyms that integrate skeletal cells, tissues, biological processes, organs (skeletal elements such as bones and cartilages), and subdivisions of the skeletal system. The VSAO is designed to integrate with other ontologies, including the Common Anatomy Reference Ontology (CARO), Gene Ontology (GO), Uberon, and Cell Ontology (CL), and it is freely available to the community to be updated with additional terms required for research. Its structure accommodates anatomical variation among vertebrate species in development, structure, and composition. Annotation of diverse vertebrate phenotypes with this ontology will enable novel inquiries across the full spectrum of phenotypic diversity. PMID:23251424

  5. A Unified Anatomy Ontology of the Vertebrate Skeletal System

    PubMed Central

    Dahdul, Wasila M.; Balhoff, James P.; Blackburn, David C.; Diehl, Alexander D.; Haendel, Melissa A.; Hall, Brian K.; Lapp, Hilmar; Lundberg, John G.; Mungall, Christopher J.; Ringwald, Martin; Segerdell, Erik; Van Slyke, Ceri E.; Vickaryous, Matthew K.; Westerfield, Monte; Mabee, Paula M.

    2012-01-01

    The skeleton is of fundamental importance in research in comparative vertebrate morphology, paleontology, biomechanics, developmental biology, and systematics. Motivated by research questions that require computational access to and comparative reasoning across the diverse skeletal phenotypes of vertebrates, we developed a module of anatomical concepts for the skeletal system, the Vertebrate Skeletal Anatomy Ontology (VSAO), to accommodate and unify the existing skeletal terminologies for the species-specific (mouse, the frog Xenopus, zebrafish) and multispecies (teleost, amphibian) vertebrate anatomy ontologies. Previous differences between these terminologies prevented even simple queries across databases pertaining to vertebrate morphology. This module of upper-level and specific skeletal terms currently includes 223 defined terms and 179 synonyms that integrate skeletal cells, tissues, biological processes, organs (skeletal elements such as bones and cartilages), and subdivisions of the skeletal system. The VSAO is designed to integrate with other ontologies, including the Common Anatomy Reference Ontology (CARO), Gene Ontology (GO), Uberon, and Cell Ontology (CL), and it is freely available to the community to be updated with additional terms required for research. Its structure accommodates anatomical variation among vertebrate species in development, structure, and composition. Annotation of diverse vertebrate phenotypes with this ontology will enable novel inquiries across the full spectrum of phenotypic diversity. PMID:23251424

  6. Amphibians and Reptiles of Los Alamos County

    SciTech Connect

    Teralene S. Foxx; Timothy K. Haarmann; David C. Keller

    1999-10-01

    Recent studies have shown that amphibians and reptiles are good indicators of environmental health. They live in terrestrial and aquatic environments and are often the first animals to be affected by environmental change. This publication provides baseline information about amphibians and reptiles that are present on the Pajarito Plateau. Ten years of data collection and observations by researchers at Los Alamos National Laboratory, the University of New Mexico, the New Mexico Department of Game and Fish, and hobbyists are represented.

  7. Transdermal delivery of corticosterone in terrestrial amphibians.

    PubMed

    Wack, Corina L; Lovern, Matthew B; Woodley, Sarah K

    2010-12-01

    Stressors elicit allostatic responses that allow animals to cope with changing and challenging environments and also cause release of glucocorticoid hormones (GCs). Compared to other vertebrate classes, relatively little is known about amphibian behavioral and physiological responses to GCs. To understand the effects of elevated plasma GCs in amphibians, exogenous application of GCs is necessary, but traditional methods to elevate GCs require handling and/or anesthesia which themselves are stressors. A less invasive alternative successfully used in birds and reptiles utilizes transdermal delivery by applying GCs via a dermal patch. We asked whether dermal patches containing corticosterone (CORT, the main GC in amphibians) would elevate plasma CORT in terrestrial salamanders and frogs. We explored the use of the dermal patch to deliver CORT in an acute, sustained, and repeated manner. Patches adhered well to the amphibians' moist skin and were easily removed to regulate the time course of CORT delivery. Application of CORT treated patches elevated plasma CORT concentrations compared to vehicle patches in all species. Patches delivered physiological levels of plasma CORT in ecologically relevant time frames. Repeated application and removal of CORT patches were used to simulate exposure to repeated stressors. Application of patches did not represent a stressor because plasma CORT concentrations were similar between animals that received vehicle patches and untreated animals. Thus, transdermal delivery of GCs represents a potentially useful tool to better understand amphibian allostatic responses to stressors, and perhaps amphibian population declines. PMID:20850442

  8. Semipermeability of the nuclear membrane in the intact cell.

    PubMed

    HARDING, C V; FELDHERR, C

    1959-07-20

    The osmotic properties of nuclei in intact cells were studied by injecting solutions into the cytoplasm of amphibian oocytes. Subsequent changes in nuclear volume were recorded photographically. The injection of solutions containing polyvinylpyrrolidone or bovine serum albumin caused changes in nuclear volume which were related to the colloid osmotic pressure of the solution injected. The concentration in which no significant nuclear volume change occurred (the isotonic range) was 1.0 to 1.5 per cent polyvinylpyrrolidone (2.0 to 3.75 x 10(-4)M). 2 per cent bovine serum albumin had no significant effect on nuclear volume, whereas 4 per cent caused a significant decrease. The significance of these findings is discussed in terms of the permeability characteristics of the nuclear membrane. PMID:13664918

  9. Establishing a baseline and faunal history in amphibian monitoring programs: The amphibians of Harris Neck, GA

    USGS Publications Warehouse

    Dodd, C.K., Jr.; Barichivich, W.J.

    2007-01-01

    We conducted an intensive inventory of Harris Neck National Wildlife Refuge in coastal Georgia to determine the feasibility of establishing an amphibian monitoring program at this location. Thirteen semi-aquatic amphibian species were identified at 21 locations. Amphibian species richness at Harris Neck was similar to that of nearby barrier islands. The amphibian fauna of Harris Neck has long been affected by human-induced landscape changes, including the inadvertent introduction of tadpoles from distant fish hatcheries and the creation of artificial impoundments. Land-use history provides important information necessary to understand current amphibian distribution, especially when census data are used to establish a baseline from which to monitor future status and trends.

  10. Vertebral development and amphibian evolution.

    PubMed

    Carroll, R L; Kuntz, A; Albright, K

    1999-01-01

    Amphibians provide an unparalleled opportunity to integrate studies of development and evolution through the investigation of the fossil record of larval stages. The pattern of vertebral development in modern frogs strongly resembles that of Paleozoic labyrinthodonts in the great delay in the ossification of the vertebrae, with the centra forming much later than the neural arches. Slow ossification of the trunk vertebrae in frogs and the absence of ossification in the tail facilitate the rapid loss of the tail during metamorphosis, and may reflect retention of the pattern in their specific Paleozoic ancestors. Salamanders and caecilians ossify their centra at a much earlier stage than frogs, which resembles the condition in Paleozoic lepospondyls. The clearly distinct patterns and rates of vertebral development may indicate phylogenetic separation between the ultimate ancestors of frogs and those of salamanders and caecilians within the early radiation of ancestral tetrapods. This divergence may date from the Lower Carboniferous. Comparison with the molecular regulation of vertebral development described in modern mammals and birds suggests that the rapid chondrification of the centra in salamanders relative to that of frogs may result from the earlier migration of sclerotomal cells expressing Pax1 to the area surrounding the notochord. PMID:11324019

  11. The phylogeny of amphibian metamorphosis.

    PubMed

    Reiss, John O

    2002-01-01

    Frogs have one of the most extreme metamorphoses among vertebrates. How did this metamorphosis evolve? By combining the methods previously proposed by Mabee and Humphries (1993) and Velhagen (1997), I develop a phylogenetic method suited for rigorous analysis of this question. In a preliminary analysis using 12 transformation sequence characters and 36 associated event sequence characters, all drawn from the osteology of the skull, the evolution of metamorphosis is traced on an assumed phylogeny. This phylogeny has lissamphibians (frogs, salamanders, and caecilians) monophyletic, with frogs the sister group of salamanders. Successive outgroups used are temnospondyls and discosauriscids, both of which are fossil groups for which ontogenetic data are available. In the reconstruction of character evolution, an unambiguous change (synapomorphy) along the branch leading to lissamphibians is a delay in the lengthening of the maxilla until metamorphosis, in accordance with my previous suggestion (Reiss, 1996). However, widening of the interpterygoid vacuity does not appear as a synapomophy of lissamphibians, due to variation in the character states in the outgroups. From a more theoretical perspective, the reconstructed evolution of amphibian metamorphosis involves examples of heterochrony, through the shift of ancestral premetamorphic events to the metamorphic period, caenogenesis, through the origin of new larval features, and terminal addition, through the origin of new adult features. Other changes don't readily fit these categories. This preliminary study provides evidence that metamorphic changes in frogs arose as further modifications of changes unique to lissamphibians, as well as a new method by which such questions can be examined. PMID:16351859

  12. Demographic responses of amphibians to wetland restoration in Carolina bays on the Savannah River Site.

    SciTech Connect

    Kinkead, Karen E.

    2004-09-30

    This project studied the effects of wetland restoration on amphibian populations. These wetlands were Carolina bays located on the Savannah River Site, located near Aiken, S.C. The Savannah River Site is a National Environmental Research Park owned and operated by the U.S. Department of Energy. The study sites included three reference bays (functionally intact), three control bays (with active drainage ditches), six treatment bays (restored during 2001), and four bays near two of the treatment bays (in effect creating two metapopulations).

  13. Estimating terrestrial amphibian pesticide body burden through dermal exposure

    EPA Science Inventory

    Dermal exposure presents a potentially significant but understudied route for pesticide uptake in terrestrial amphibians. Our study measured dermal uptake of pesticides of varying hydrophobicity (logKow) in frogs. Amphibians were indirectly exposed to one of five pesticide active...

  14. ESTIMATING AMPHIBIAN OCCUPANCY RATES IN PONDS UNDER COMPLEX SURVEY DESIGNS

    EPA Science Inventory

    Monitoring the occurrence of specific amphibian species in ponds is one component of the US Geological Survey's Amphibian Monitoring and Research Initiative. Two collaborative studies were conducted in Olympic National Park and southeastern region of Oregon. The number of ponds...

  15. Amphibian parathyroids: morphological and functional aspects.

    PubMed

    Srivastav, A K; Das, V K; Das, S; Sasayama, Y; Suzuki, N

    1995-10-01

    Amphibians living partially or totally in a terrestrial environment are the first tetrapods to possess parathyroid glands. Purely aquatic amphibians and amphibian larvae lack these endocrine glands. The parathyroids develop at the time of metamorphosis. The parathyroid glands in caecilians consist of a single cell type, that of urodeles may be composed of basal (supporting) cells and suprabasal (chief) cells, and that of anurans of small and large chief cells. Parathyroid glands of caecilians and anurans lack connective tissue, blood vessels, and nerves. The parathyroid cells become activated in response to decreased blood calcium concentration and undergo changes indicating increased parathyroid hormone secretion. Increased blood calcium concentration suppresses secretory activity. Usually, parathyroidectomy elicits hypocalcemia in most amphibians. Such operations have no effect in lower urodeles. Parathyroid hormone administration provokes hypercalcemia in most amphibians. The parathyroids of caecilians have not been studied in detail. The urodeles and anurans exhibit seasonal changes in the parathyroid glands. These changes may be initiated by environmental stimuli such as light, temperature, or alterations in blood calcium levels caused by natural hibernation. PMID:8580512

  16. Intact capture of hypervelocity particles

    NASA Technical Reports Server (NTRS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    1986-01-01

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  17. Intact capture of hypervelocity particles

    NASA Astrophysics Data System (ADS)

    Tsou, P.; Brownlee, D. E.; Albee, A. L.

    Knowledge of the phase, structure, and crystallography of cosmic particles, as well as their elemental and isotopic compositions, would be very valuable information toward understanding the nature of our solar system. This information can be obtained from the intact capture of large mineral grains of cosmic particles from hypervelocity impacts. Hypervelocity experiments of intact capture in underdense media have indicated realistic potential in this endeaver. The recovery of the thermal blankets and louvers from the Solar Max spacecraft have independently verified this potential in the unintended capture of cosmic materials from hypervelocity impacts. Passive underdense media will permit relatively simple and inexpensive missions to capture cosmic particles intact, either by going to a planetary body or by waiting for the particles to come to the Shuttle or the Space Station. Experiments to explore the potential of using various underdense media for an intact comet sample capture up to 6.7 km/s were performed at NASA Ames Research Center Vertical Gun Range. Explorative hypervelocity experiments up to 7.9 km/s were also made at the Ernst Mach Institute. These experiments have proven that capturing intact particles at hypervelocity impacts is definitely possible. Further research is being conducted to achieve higher capture ratios at even higher hypervelocities for even smaller projectiles.

  18. Pulmonary compliance and lung volume are related to terrestriality in anuran amphibians.

    PubMed

    Withers, Philip C; Hedrick, Michael S; Drewes, Robert C; Hillman, Stanley S

    2014-01-01

    Dehydration tolerance of anuran amphibians is directly related to their ability to mobilize lymphatic reserves, with more terrestrial species having more effective lymph mobilization dependent on specialized skeletal muscles acting directly on the lymph sacs and via pulmonary ventilation. Consequently, we tested the hypothesis that pulmonary compliance, lung volume, and femoral lymphatic sac volume were related to terrestriality-and, hence, lymph mobilization-for 18 species of aquatic, semiaquatic, or terrestrial anuran amphibians. Lung compliance and volume were significantly related to body mass, but there was no significant phylogenetic pattern. There were significant habitat-related patterns for mass-corrected and phylogenetically corrected residuals for these pulmonary variables. Femoral lymph volume was significantly related to body mass, with no significant phylogenetic pattern, and there was only a weak correlation for habitat with mass-corrected and phylogenetically corrected residuals. These results suggest that pulmonary volume and compliance are strongly related to terrestriality in anuran amphibians and are under significant selection pressure to enhance lymph mobilization, but lymph sac volume does not appear to have a major role in adaptation to terrestriality. PMID:24769702

  19. Amphibians of the northern Great Plains

    USGS Publications Warehouse

    Larson, Diane L.; Euliss, Ned H.; Lannoo, Michael J.; Mushet, David M.

    1998-01-01

    No cry of alarm has been sounded over the fate of amphibian populations in the northern grasslands of North America, yet huge percentages of prairie wetland habitat have been lost, and the destruction continues. Scarcely 30% of the original mixedgrass prairie remains in Nebraska, South Dakota, and North Dakota (See Table 1 in this chapter). If amphibian populations haven’t declined, why haven’t they? Or, have we simply failed to notice? Amphibians in the northern grasslands evolved in a boom-or-bust environment: species that were unable to survive droughts lasting for years died out long before humans were around to count them. Species we find today are expert at seizing the rare, wet moment to rebuild their populations in preparation for the next dry season. When numbers can change so rapidly, who can say if a species is rare or common? A lot depends on when you look.

  20. Amphibian monitoring in the Atchafalaya Basin

    USGS Publications Warehouse

    Waddle, Hardin

    2011-01-01

    Amphibians are a diverse group of animals that includes frogs, toads, and salamanders. They are adapted to living in a variety of habitats, but most require water for at least one life stage. Amphibians have recently become a worldwide conservation concern because of declines and extinctions even in remote protected areas previously thought to be safe from the pressures of habitat loss and degradation. Amphibians are an important part of ecosystem dynamics because they can be quite abundant and serve both as a predator of smaller organisms and as prey to a suite of vertebrate predators. Their permeable skin and aquatic life history also make them useful as indicators of ecosystem health. Since 2002, the U.S. Geological Survey has been studying the frog and toad species inhabiting the Atchafalaya Basin to monitor for population declines and to better understand how the species are potentially affected by disease, environmental contaminants, and climate change.

  1. Emesis and Space Motion Sickness in Amphibians

    NASA Astrophysics Data System (ADS)

    Naitoh, T.; Yamashita, M.; Izumi-Kurotani, A.; Takabatake, I.; Wassersug, R. J.

    Amphibians possess the ability to vomit in response to a variety of stimuli that provoke emesis in mammals. Pharmacological studies have establish that the ejection of gastric contents and the basic mechanism for vomiting have been phylogenetically conserved among these tetrapods. As part of on-going comparative studies on emesis in vertebrates, we previously documented that some postmetamorphic anurans and salamander larvae experience motion-induced emesis when exposed to the provocative stimulus of parabolic aircraft flight. However, more recent experiments suggest that there are strict conditions for inducing emesis in amphibians exposed to parabolic flight and that amphibians are not as sensitive to this stimulus as mammals. Further studies on emesis in lower vertebrates may help us understand the processes that cause emesis in abnormal gravitational regimes

  2. Microbiota and Mucosal Immunity in Amphibians

    PubMed Central

    Colombo, Bruno M.; Scalvenzi, Thibault; Benlamara, Sarah; Pollet, Nicolas

    2015-01-01

    We know that animals live in a world dominated by bacteria. In the last 20 years, we have learned that microbes are essential regulators of mucosal immunity. Bacteria, archeas, and viruses influence different aspects of mucosal development and function. Yet, the literature mainly covers findings obtained in mammals. In this review, we focus on two major themes that emerge from the comparative analysis of mammals and amphibians. These themes concern: (i) the structure and functions of lymphoid organs and immune cells in amphibians, with a focus on the gut mucosal immune system; and (ii) the characteristics of the amphibian microbiota and its influence on mucosal immunity. Lastly, we propose to use Xenopus tadpoles as an alternative small-animal model to improve the fundamental knowledge on immunological functions of gut microbiota. PMID:25821449

  3. Design of an Amphibian Exploring Robot

    NASA Astrophysics Data System (ADS)

    Maity, Atanu; Majumder, Somajyoti

    2014-07-01

    To design and develop an amphibian exploring robot capable of operation in constrained mine environment puts a tremendous challenge to the system developers from both scientific and engineering perspective. Very few attempts have been made to fulfil these criteria of versatility in design, communication and control. The CSIR-CMERI developed amphibian subterranean robotic explorer (SR) is capable of moving over fairly rough terrain. It can swim as well as crawl over basin floor effortlessly. It is capable of operating at a maximum depth of 10m and can swim at 1 knot. A number of field trials have been carried out for performance testing of the system to ascertain its capability in underground flooded mine tunnels. This paper presents the insight on the design of an amphibian exploring robot for mine safety and disaster mitigation with special features of low power consumption vis-a-vis high mission time.

  4. Skeletal anomalies.

    PubMed

    Dugoff, L; Thieme, G; Hobbins, J C

    2000-12-01

    It is possible to identify many types of skeletal dysplasias and conditions involving limb deformities prenatally using ultrasound. It is likely that in the future, with the advancing technology and discoveries in molecular genetics, specific mutation analysis will become available for many of these conditions. This will make first trimester diagnosis an option in many cases. Because of the complex nature of many of these cases, it may be helpful to use a multidisciplinary approach involving a radiologist and a geneticist at times. In utero radiographs may help clarify a diagnosis. In lethal cases where a specific diagnosis has not been confirmed, it may be helpful postpartum to obtain an autopsy; photographs; complete body radiographs; karyotypic analysis; and specimens of bone, cartilage, and fetal blood for further analysis. PMID:11816496

  5. Skeletal Scintigraphy

    PubMed Central

    McDougall, I. Ross

    1979-01-01

    Skeletal scintigraphy, using phosphates or diphosphonates labeled with technetium 99m, is a sensitive method of detecting bone abnormalities. The most important and most frequent role of bone scanning is evaluating the skeletal areas in patients who have a primary cancer, especially a malignant condition that has a tendency to spread to bone areas. The bone scan is superior to bone radiographs in diagnosing these abnormalities; 15 percent to 25 percent of patients with breast, prostate or lung cancer, who have normal roentgenograms, also have abnormal scintigrams due to metastases. The majority of bone metastases appear as hot spots on the scan and are easily recognized. The incidence of abnormal bone scans in patients with early stages (I and II) of breast cancer varies from 6 percent to 26 percent, but almost invariably those patients with scan abnormalities have a poor prognosis and should be considered for additional therapies. Progression or regression of bony lesions can be defined through scanning, and abnormal areas can be identified for biopsy. The incidence of metastases in solitary scan lesions in patients with known primary tumors varies from 20 percent to 64 percent. Bone scintigraphy shows positive uptake in 95 percent of cases with acute osteomyelitis. Stress fractures and trauma suspected in battered babies can be diagnosed by scanning before there is radiological evidence. The procedure is free from acute or long-term side effects and, except in cases of very young patients, sedation is seldom necessary. Although the test is sensitive, it is not specific and therefore it is difficult to overemphasize the importance of clinical, radiographic, biochemical and scanning correlation in each patient. ImagesFigure 2.Figure 3.Figure 4.Figure 5.Figure 6.Figure 7.Figure 8.Figure 9.Figure 10. PMID:390886

  6. Intact capture of cosmic dust

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1991-01-01

    The focus of this development effort is to capture dust particles at hypervelocities intact and unmelted in order to preserve volatile organics. At the same time, the capture process must minimize any organic elemental or compound contamination to prevent any compromise of exobiological analyses. Inorganic silicate aerogel has been developed as a successful capture medium to satisfy both requirements of intact capture and minimal organic contamination. Up to 6 km/s, silicate projectiles from a few microns up to 100 microns have been captured intact without any melting and with minimal loss of mass. Carbon in silicate aerogel can be reduced to less than 1 part in 1000 and hydrogen 3 parts in 1000 when baked in air. Under controlled inert gas environments, additional hydrocarbon reduction can be achieved.

  7. The amphibian pathogen Batrachochytrium dendrobatidis detected in a community of stream and wetland amphibians

    USGS Publications Warehouse

    Grant, E.H.C.; Bailey, L.L.; Ware, J.L.; Duncan, K.C.

    2008-01-01

    The amphibian chytrid fungus Batrachochytrium dendrobatidis, responsible for the potentially fatal amphibian disease chytridiomycosis, is known to occur in a large and ever increasing number of amphibian populations around the world. However, sampling has been biased towards stream- and wetland-breeding anurans, with little attention paid to stream-associated salamanders. We sampled three frog and three salamander species in the Chesapeake and Ohio Canal National Historic Park, Maryland, by swabbing animals for PCR analysis to detect DNA of B. dendrobatidis. Using PCR, we detected B. dendrobatidis DNA in both stream and wetland amphibians, and report here the first occurrence of the pathogen in two species of stream-associated salamanders. Future research should focus on mechanisms within habitats that may affect persistence and dissemination of B. dendrobatidis among stream-associated salamanders.

  8. Helping Your Local Amphibians (HYLA): An Internet-based Amphibian Course for Educators.

    ERIC Educational Resources Information Center

    Murphy, Tony P.

    2001-01-01

    Introduces an online zoology course that was offered primarily to upper elementary and middle school teachers in which teachers were expected to take action to help the local amphibian population. (Author/YDS)

  9. Possible interrelations among environmental toxicants, amphibian development, and decline of amphibian populations.

    PubMed Central

    Carey, C; Bryant, C J

    1995-01-01

    Many amphibian populations are declining in a number of geographical locations throughout the world. In most cases, the cause or causes are unknown, but are assumed to result from man-made alterations in the environment. We review existing evidence concerning how environmental xenobiotics could contribute to declines of amphibian populations by impacting growth and development of the young. This paper examines the potential roles of toxicants in: a) affecting the susceptibility of young to disease; b) retarding growth and development of amphibian young; c) affecting the ability of larvae to avoid predation; d) affecting the development of physiological, morphological, or behavioral processes in a manner that subsequently impairs the ability of the young for future reproduction; and e) directly causing mortality of young. These issues are not well studied, and more studies are needed before the roles of environmental xenobiotics in amphibian declines are fully understood. PMID:7556018

  10. Presence of the amphibian chytrid fungus Batrachochytrium dendrobatidis in native amphibians exported from Madagascar.

    PubMed

    Kolby, Jonathan E

    2014-01-01

    The emerging infectious disease chytridiomycosis is driven by the spread of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd), a highly virulent pathogen threatening global amphibian biodiversity. Although pandemic in distribution, previous intensive field surveys have failed to detect Bd in Madagascar, a biodiversity hotspot home to hundreds of endemic amphibian species. Due to the presence of Bd in nearby continental Africa and the ecological crisis that can be expected following establishment in Madagascar, enhanced surveillance is imperative. I sampled 565 amphibians commercially exported from Madagascar for the presence of Bd upon importation to the USA, both to assist early detection efforts and demonstrate the conservation potential of wildlife trade disease surveillance. Bd was detected in three animals via quantitative PCR: a single Heterixalus alboguttatus, Heterixalus betsileo, and Scaphiophryne spinosa. This is the first time Bd has been confirmed in amphibians from Madagascar and presents an urgent call to action. Our early identification of pathogen presence prior to widespread infection provides the necessary tools and encouragement to catalyze a swift, targeted response to isolate and eradicate Bd from Madagascar. If implemented before establishment occurs, an otherwise likely catastrophic decline in amphibian biodiversity may be prevented. PMID:24599336

  11. Presence of the Amphibian Chytrid Fungus Batrachochytrium dendrobatidis in Native Amphibians Exported from Madagascar

    PubMed Central

    Kolby, Jonathan E.

    2014-01-01

    The emerging infectious disease chytridiomycosis is driven by the spread of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd), a highly virulent pathogen threatening global amphibian biodiversity. Although pandemic in distribution, previous intensive field surveys have failed to detect Bd in Madagascar, a biodiversity hotspot home to hundreds of endemic amphibian species. Due to the presence of Bd in nearby continental Africa and the ecological crisis that can be expected following establishment in Madagascar, enhanced surveillance is imperative. I sampled 565 amphibians commercially exported from Madagascar for the presence of Bd upon importation to the USA, both to assist early detection efforts and demonstrate the conservation potential of wildlife trade disease surveillance. Bd was detected in three animals via quantitative PCR: a single Heterixalus alboguttatus, Heterixalus betsileo, and Scaphiophryne spinosa. This is the first time Bd has been confirmed in amphibians from Madagascar and presents an urgent call to action. Our early identification of pathogen presence prior to widespread infection provides the necessary tools and encouragement to catalyze a swift, targeted response to isolate and eradicate Bd from Madagascar. If implemented before establishment occurs, an otherwise likely catastrophic decline in amphibian biodiversity may be prevented. PMID:24599336

  12. Managing Amphibian Disease with Skin Microbiota.

    PubMed

    Woodhams, Douglas C; Bletz, Molly; Kueneman, Jordan; McKenzie, Valerie

    2016-03-01

    The contribution of emerging amphibian diseases to the sixth mass extinction is driving innovative wildlife management strategies, including the use of probiotics. Bioaugmentation of the skin mucosome, a dynamic environment including host and microbial components, may not provide a generalized solution. Multi-omics technologies and ecological context underlie effective implementation. PMID:26916805

  13. ELASTICITY ANALYSIS OF AMPHIBIAN LIFE HISTORIES

    EPA Science Inventory

    By comparing life history parameters (e.g., age at metamorphosis, age at sexual maturation, egg number, longevity) and phenology of different species, we gain valuable insight into why growth rates differ across populations. Although the demography of most amphibians is lacking, ...

  14. Amphibian pathogens in Southeast Asian frog trade.

    PubMed

    Gilbert, Martin; Bickford, David; Clark, Leanne; Johnson, Arlyne; Joyner, Priscilla H; Ogg Keatts, Lucy; Khammavong, Kongsy; Nguyễn Văn, Long; Newton, Alisa; Seow, Tiffany P W; Roberton, Scott; Silithammavong, Soubanh; Singhalath, Sinpakhone; Yang, Angela; Seimon, Tracie A

    2012-12-01

    Amphibian trade is known to facilitate the geographic spread of pathogens. Here we assess the health of amphibians traded in Southeast Asia for food or as pets, focusing on Batrachochytrium dendrobatidis (Bd), ranavirus and general clinical condition. Samples were collected from 2,389 individual animals at 51 sites in Lao PDR, Cambodia, Vietnam and Singapore for Bd screening, and 74 animals in Cambodia and Vietnam for ranavirus screening. Bd was found in one frog (n = 347) in Cambodia and 13 in Singapore (n = 419). No Bd was found in Lao PDR (n = 1,126) or Vietnam (n = 497), and no ranavirus was found in Cambodia (n = 70) or Vietnam (n = 4). Mild to severe dermatological lesions were observed in all East Asian bullfrogs Hoplobatrachus rugolosus (n = 497) sampled in farms in Vietnam. Histologic lesions consistent with sepsis were found within the lesions of three frogs and bacterial sepsis in two (n = 4); one had Gram-negative bacilli and one had acid-fast organisms consistent with mycobacterium sp. These results confirm that Bd is currently rare in amphibian trade in Southeast Asia. The presence of Mycobacterium-associated disease in farmed H. rugolosus is a cause for concern, as it may have public health implications and indicates the need for improved biosecurity in amphibian farming and trade. PMID:23404036

  15. POTENTIAL DEVELOPMENTAL EFFECTS OF ATRAZINE ON AMPHIBIANS

    EPA Science Inventory

    Recent research has generated conflicting results on the effects of atrazine on gonadal developmental (e.g., male hermaphroditism) in amphibians and how these effects influence secondary sexual characteristics (e.g., laryngeal muscle mass). The SAP is being asked to consider the...

  16. Culture of Cells from Amphibian Embryos.

    ERIC Educational Resources Information Center

    Stanisstreet, Martin

    1983-01-01

    Describes a method for in vitro culturing of cells from amphibian early embryos. Such cells can be used to demonstrate such properties of eukaryote cells as cell motility, adhesion, differentiation, and cell sorting into tissues. The technique may be extended to investigate other factors. (Author/JN)

  17. Universal COI primers for DNA barcoding amphibians.

    PubMed

    Che, Jing; Chen, Hong-Man; Yang, Jun-Xiao; Jin, Jie-Qiong; Jiang, Ke; Yuan, Zhi-Yong; Murphy, Robert W; Zhang, Ya-Ping

    2012-03-01

    DNA barcoding is a proven tool for the rapid and unambiguous identification of species, which is essential for many activities including the vouchering tissue samples in the genome 10K initiative, genealogical reconstructions, forensics and biodiversity surveys, among many other applications. A large-scale effort is underway to barcode all amphibian species using the universally sequenced DNA region, a partial fragment of mitochondrial cytochrome oxidase subunit I COI. This fragment is desirable because it appears to be superior to 16S for barcoding, at least for some groups of salamanders. The barcoding of amphibians is essential in part because many species are now endangered. Unfortunately, existing primers for COI often fail to achieve this goal. Herein, we report two new pairs of primers (➀, ➁) that in combination serve to universally amplify and sequence all three orders of Chinese amphibians as represented by 36 genera. This taxonomic diversity, which includes caecilians, salamanders and frogs, suggests that the new primer pairs will universally amplify COI for the vast majority species of amphibians. PMID:22145866

  18. Diseases of amphibian eggs and embryos

    USGS Publications Warehouse

    Green, D.E.; Converse, K.A.

    2005-01-01

    Amphibians generally are prolific egg producers. In tropical and semi-tropical regions, deposition of eggs may occur year-round or may coincide with rainy seasons, while in temperate regions, deposition of eggs usually occurs immediately after emergence from hibernation. Numbers of eggs produced by each species may vary from a few dozen to thousands. Accordingly, some eggs may be infertile and wastage of embryos is to be expected. Fertility, viability and decomposition of eggs and embryos must be considered before it is assumed that diseases are present. An important consideration in the evaluation of egg masses is the fact that some will contain infertile and non-viable eggs. These infertile and nonviable eggs will undergo decomposition and they may appear similar to eggs that are infected by a pathogen. Evaluation of egg masses and embryos for the presence of disease may require repeated observations in a given breeding season as well as continued monitoring of egg masses during their growth and development and over successive breeding seasons. Amphibian eggs rarely are subjected to a comprehensive health (diagnostic) examination; hence, there is scant literature on the diseases of this life stage. Indeed, the eggs of some North American amphibians have yet to be described. Much basic physiology and normal biomedical baseline data on amphibian eggs is lacking. For example, it is known that the aquatic eggs of some species of shrimp quickly are coated by a protective and commensal bacterium that effectively impedes invasion of the eggs by other environmental organisms and potential pathogens. In the absence of this bacterium, shrimp eggs are rapidly killed by other bacteria and fungi (Green, 2001). The possibility that amphibian eggs also have important symbiotic or commensal bacteria needs to be investigated. Furthermore, the quantity and types of chemicals in the normal gelatinous capsules of amphibian eggs have scarcely been examined. Abnormalities of the

  19. Monitoring Intact Viruses Using Aptamers.

    PubMed

    Kumar, Penmetcha K R

    2016-01-01

    Viral diagnosis and surveillance are necessary steps in containing the spread of viral diseases, and they help in the deployment of appropriate therapeutic interventions. In the past, the commonly employed viral detection methods were either cell-culture or molecule-level assays. Most of these assays are laborious and expensive, require special facilities, and provide a slow diagnosis. To circumvent these limitations, biosensor-based approaches are becoming attractive, especially after the successful commercialization of glucose and other biosensors. In the present article, I have reviewed the current progress using the biosensor approach for detecting intact viruses. At the time of writing this review, three types of bioreceptor surfaces (antibody-, glycan-, and aptamer-based) have been explored on different sensing platforms for detecting intact viruses. Among these bioreceptors, aptamer-based sensors have been increasingly explored for detecting intact viruses using surface plasmon resonance (SPR) and other platforms. Special emphasis is placed on the aptamer-based SPR platform in the present review. PMID:27527230

  20. Establishing causality in the decline and deformity of amphibians: The amphibian research and monitoring initiative model

    USGS Publications Warehouse

    Little, E.E.; Bridges, C.M.; Linder, G.; Boone, M.

    2003-01-01

    Research to date has indicated that a range of environmental variables such as disease, parasitism, predation, competition, environmental contamination, solar ultraviolet radiation, climate change, or habitat alteration may be responsible for declining amphibian populations and the appearance of deformed organisms, yet in many cases no definitive environmental variable stands out as a causal factor. Multiple Stressors are often present in the habitat, and interactions among these can magnify injury to biota. This raises the possibility that the additive or synergistic impact of these Stressors may be the underlying cause of amphibian declines. Effective management for the restoration of amphibian populations requires the identification of causal factors contributing to their declines. A systematic approach to determine causality is especially important because initial impressions may be misleading or ambiguous. In addition, the evaluation of amphibian populations requires consideration of a broader spatial scale than commonly used in regulatory monitoring. We describe a systematic three-tiered approach to determine causality in amphibian declines and deformities. Tier 1 includes an evaluation of historic databases and extant data and would involve a desktop synopsis of the status of various stressors as well as site visits. Tier 2 studies are iterative, hypothesis driven studies beginning with general tests and continuing with analyses of increasing complexity as certain stressors are identified for further investigation. Tier 3 applies information developed in Tier 2 as predictive indicators of habitats and species at risk over broad landscape scales and provides decision support for the adaptive management of amphibian recovery. This comprehensive, tiered program could provide a mechanistic approach to identifying and addressing specific stressors responsible for amphibian declines across various landscapes.

  1. Language and Williams syndrome: how intact is "intact"?

    PubMed

    Karmiloff-Smith, A; Grant, J; Berthoud, I; Davies, M; Howlin, P; Udwin, O

    1997-04-01

    It has been claimed that Williams syndrome (WS), a rare neurodevelopmental disorder, is characterized by serious cognitive deficits alongside intact language. The syndrome is often used as a prime example of the modularity of an innate faculty for morphosyntactic rules. We challenge this claim and hypothesize that morphosyntax, although surprisingly good given WS level of mental retardation, is by no means intact. We make an initial test of this hypothesis through an analysis of the receptive language of a group of English-speaking WS individuals on a standardized morphosyntactic test. We then present an experimental study of expressive language that examines grammatical gender assignment in French-speaking WS patients. Despite a Verbal Mental Age selected to be higher than the chronological age of the young control group, these people with WS continue even in adulthood to show clear-cut deficits in their production of an aspect of morphosyntax that normal children acquire effortlessly very early. The results of the 2 studies, one focusing on receptive language and the other on expressive language, challenge the notion that comprehension and use of morphosyntactic rules in WS individuals are intact. The Within-domain dissociations regarding the use of grammatical gender assignment across several sentence clements and their difficulties in understanding embedded sentences-two quintessentially linguistic skills-suggest that we must rethink the notion of spared, modular, language capacities in Williams syndrome. We conclude that WS language follows a different path to normal acquisition and may turn out to be more like second language learning. PMID:9180000

  2. Helping Your Local Amphibians (HYLA): An Internet-Based Amphibian Course for Educators

    NASA Astrophysics Data System (ADS)

    Murphy, Tony P.

    2001-12-01

    A pilot on-line course on amphibians was offered free to 20 educators around the United States in 1999. This course, called Helping Your Local Amphibians (HYLA), was the first of its kind on-line course for educators dealing with amphibian issues. It also used these animals as a focus to teach about the environment. The course lasted 9 weeks with some additional time for continued discussions and used various aspects of Internet technology (including a virtual conference center), media, and traditional paper-based products to complete the learning process. Five teachers were selected to attend a national amphibian summit hosted by the Center for Global Environmental Education, Hamline University, St. Paul, MN. The course was aimed primarily at upper elementary and middle school teachers, but participants included formal and nonformal educators. For the most part, educators expressed satisfaction with the course and the content, as well as the structure of the web site. For 80% of the group, this was their first Internet-based course. In addition, as part of the course, the educators were expected to take some action with their primary audiences to help local amphibian populations. This mainly took the form of surveys or habitat clean-ups. The development of the course was underwritten by grants from the National Fish and Wildlife Foundation, U.S. Fish and Wildlife Service, the Best Buy Children's Foundation, and Hamline University.

  3. Research proceedings on amphibian model organisms

    PubMed Central

    LIU, Lu-Sha; ZHAO, Lan-Ying; WANG, Shou-Hong; JIANG, Jian-Ping

    2016-01-01

    Model organisms have long been important in biology and medicine due to their specific characteristics. Amphibians, especially Xenopus, play key roles in answering fundamental questions on developmental biology, regeneration, genetics, and toxicology due to their large and abundant eggs, as well as their versatile embryos, which can be readily manipulated and developed in vivo. Furthermore, amphibians have also proven to be of considerable benefit in human disease research due to their conserved cellular developmental and genomic organization. This review gives a brief introduction on the progress and limitations of these animal models in biology and human disease research, and discusses the potential and challenge of Microhyla fissipes as a new model organism. PMID:27469255

  4. Research proceedings on amphibian model organisms.

    PubMed

    Liu, Lu-Sha; Zhao, Lan-Ying; Wang, Shou-Hong; Jiang, Jian-Ping

    2016-07-18

    Model organisms have long been important in biology and medicine due to their specific characteristics. Amphibians, especially Xenopus, play key roles in answering fundamental questions on developmental biology, regeneration, genetics, and toxicology due to their large and abundant eggs, as well as their versatile embryos, which can be readily manipulated and developed in vivo. Furthermore, amphibians have also proven to be of considerable benefit in human disease research due to their conserved cellular developmental and genomic organization. This review gives a brief introduction on the progress and limitations of these animal models in biology and human disease research, and discusses the potential and challenge of Microhyla fissipes as a new model organism. PMID:27469255

  5. Neurosteroid Biosynthesis in the Brain of Amphibians

    PubMed Central

    Vaudry, Hubert; Do Rego, Jean-Luc; Burel, Delphine; Luu-The, Van; Pelletier, Georges; Vaudry, David; Tsutsui, Kazuyoshi

    2011-01-01

    Amphibians have been widely used to investigate the synthesis of biologically active steroids in the brain and the regulation of neurosteroid production by neurotransmitters and neuropeptides. The aim of the present review is to summarize the current knowledge regarding the neuroanatomical distribution and biochemical activity of steroidogenic enzymes in the brain of anurans and urodeles. The data accumulated over the past two decades demonstrate that discrete populations of neurons and/or glial cells in the frog and newt brains express the major steroidogenic enzymes and are able to synthesize de novo a number of neurosteroids from cholesterol/pregnenolone. Since neurosteroidogenesis has been conserved during evolution from amphibians to mammals, it appears that neurosteroids must play important physiological functions in the central nervous system of vertebrates. PMID:22649387

  6. Direct and indirect effects of climate change on amphibian populations

    USGS Publications Warehouse

    Blaustein, Andrew R.; Walls, Susan C.; Bancroft, Betsy A.; Lawler, Joshua J.; Searle, Catherine L.; Gervasi, Stephanie S.

    2010-01-01

    As part of an overall decline in biodiversity, populations of many organisms are declining and species are being lost at unprecedented rates around the world. This includes many populations and species of amphibians. Although numerous factors are affecting amphibian populations, we show potential direct and indirect effects of climate change on amphibians at the individual, population and community level. Shifts in amphibian ranges are predicted. Changes in climate may affect survival, growth, reproduction and dispersal capabilities. Moreover, climate change can alter amphibian habitats including vegetation, soil, and hydrology. Climate change can influence food availability, predator-prey relationships and competitive interactions which can alter community structure. Climate change can also alter pathogen-host dynamics and greatly influence how diseases are manifested. Changes in climate can interact with other stressors such as UV-B radiation and contaminants. The interactions among all these factors are complex and are probably driving some amphibian population declines and extinctions.

  7. Emerging infectious diseases and amphibian population declines.

    PubMed Central

    Daszak, P.; Berger, L.; Cunningham, A. A.; Hyatt, A. D.; Green, D. E.; Speare, R.

    1999-01-01

    We review recent research on the pathology, ecology, and biogeography of two emerging infectious wildlife diseases, chytridiomycosis and ranaviral disease, in the context of host-parasite population biology. We examine the role of these diseases in the global decline of amphibian populations and propose hypotheses for the origins and impact of these panzootics. Finally, we discuss emerging infectious diseases as a global threat to wildlife populations. PMID:10603206

  8. Bent's Old Fort: Amphibians and Reptiles

    USGS Publications Warehouse

    Muths, E.

    2008-01-01

    Bent's Old Fort National Historic Site sits along the Arkansas River in the semi-desert prairie of southeastern Colorado. The USGS provided assistance in designing surveys to assess the variety of herpetofauna (amphibians and reptiles) resident at this site. This brochure is the results of those efforts and provides visitors with information on what frogs, toads, snakes and salamanders might be seen and heard at Bent's Old Fort.

  9. Amphibians as research models for regenerative medicine

    PubMed Central

    Song, Fengyu; Li, Bingbing

    2010-01-01

    The ability to regenerate bone across a critical size defect would be a marked clinical advance over current methods for dealing with such structural gaps. Here, we briefly review the development of limb bones and the mandible, the regeneration of urodele limbs after amputation, and present evidence that urodele and anuran amphibians represent a valuable research model for the study of segment defect regeneration in both limb bones and mandible. PMID:21197215

  10. Ranavirus outbreaks in amphibian populations of northern Idaho

    USGS Publications Warehouse

    Russell, Danelle M.; Goldberg, Caren S.; Sprague, Laura; Waits, Lisette P.; Green, D. Earl; Schuler, Krysten L.; Rosenblum, Erica Bree

    2011-01-01

    Ranavirus outbreaks, caused by pathogens in the genus Ranavirus (Family Iridoviridae), were the largest single cause of reported amphibian mass mortality events in the United States from 1996–2001 (Green et al. 2002). Mortality events associated with ranaviruses have been documented on five continents and throughout the latitudes and elevations where amphibians occur (Gray et al. 2009). However, the threat of ranaviruses to amphibian and reptile populations in specific regions is still largely unknown (Chinchar 2002; Gray et al. 2009).

  11. Pesticide Detection in Rainwater, Stemflow, and Amphibians from Agricultural Spray Drift in Southern Georgia, USA

    EPA Science Inventory

    Amphibians are important sentinel environmental species since they integrate stressors from both aquatic and terrestrial ecosystems. Pesticides are well established as a significant stressor for amphibians. In order to study spray-drift contributions to amphibian habitats, pestic...

  12. Pesticide Uptake Across the Amphibian Dermis Through Soil and Overspray Exposures

    EPA Science Inventory

    For terrestrial amphibians, accumulation ofpesticides through dermal contact is a primary route ofexposure in agricultural landscapes and may be contributingto widespread amphibian declines. To show pesticidetransfer across the amphibian dermis at permitted labelapplication rates...

  13. Amphibian Decline: An Integrated Analysis of Multiple Stressor Effects

    USGS Publications Warehouse

    2003-01-01

    Although the effects of contaminants on amphibians have been studied for decades, relatively little is known about these effects compared to the more intensively studied mammals. and birds. Science has advanced its understanding of the complexities linked to declining amphibian populations; however, there are many remaining questions whose answers would directly benefit amphibians and adaptive management plans ministering to them. In an effort to answer those questions and focus on ecological risk assessment of amphibians, scientists, researchers, and resource management professionals from diverse fields participated in a Society of Environmental Toxicology and Chemistry (SETAC)-Johnson Foundation Wingspread conference with three goals: characterize a process that would bring a range of interdisciplinary technical and management tools to the tasks of causal analysis; demonstrate the current state of available technical tools to assess amphibian populations exposed to various environmental stressors; and focus on identifying research that would likely benefit sustainable populations through adaptive management programs. A result of the Wingspread conference, Amphibian Decline examines the ecotoxicology and stressors of amphibians in an attempt to address issues related to declining amphibian populations and the role that various stressors might have in those losses. It identifies gaps in current data, interprets information into an existing framework, and points toward critical areas for future research. Through the combined efforts of research and resource management communities, recommendations can be developed to change current policies and management actions to address the problem of amphibian decline.

  14. Global rates of habitat loss and implications for amphibian conservation

    USGS Publications Warehouse

    Gallant, A.L.; Klaver, R.W.; Casper, G.S.; Lannoo, M.J.

    2007-01-01

    A large number of factors are known to affect amphibian population viability, but most authors agree that the principal causes of amphibian declines are habitat loss, alteration, and fragmentation. We provide a global assessment of land use dynamics in the context of amphibian distributions. We accomplished this by compiling global maps of amphibian species richness and recent rates of change in land cover, land use, and human population growth. The amphibian map was developed using a combination of published literature and digital databases. We used an ecoregion framework to help interpret species distributions across environmental, rather than political, boundaries. We mapped rates of land cover and use change with statistics from the World Resources Institute, refined with a global digital dataset on land cover derived from satellite data. Temporal maps of human population were developed from the World Resources Institute database and other published sources. Our resultant map of amphibian species richness illustrates that amphibians are distributed in an uneven pattern around the globe, preferring terrestrial and freshwater habitats in ecoregions that are warm and moist. Spatiotemporal patterns of human population show that, prior to the 20th century, population growth and spread was slower, most extensive in the temperate ecoregions, and largely exclusive of major regions of high amphibian richness. Since the beginning of the 20th century, human population growth has been exponential and has occurred largely in the subtropical and tropical ecoregions favored by amphibians. Population growth has been accompanied by broad-scale changes in land cover and land use, typically in support of agriculture. We merged information on land cover, land use, and human population growth to generate a composite map showing the rates at which humans have been changing the world. When compared with the map of amphibian species richness, we found that many of the regions of the

  15. Conceptual Design for the Amphibian Research and Monitoring Initiative (ARMI)

    NASA Astrophysics Data System (ADS)

    Battaglin, W. A.; Langtimm, C. A.; Adams, M. J.; Gallant, A. L.; James, D. L.

    2001-12-01

    In 2000, the President of the United States (US) and Congress directed Department of Interior (DOI) agencies to develop a program for monitoring trends in amphibian populations on DOI lands and to conduct research into causes of declines. The U.S. Geological Survey (USGS) was given lead responsibility for planning and implementing the Amphibian Research and Monitoring Initiative (ARMI) in cooperation with the National Park Service (NPS), Fish and Wildlife Service, and Bureau of Land Management. The program objectives are to (1) establish a network for monitoring the status and distribution of amphibian species on DOI lands; (2) identify and monitor environmental conditions known to affect amphibian populations; (3) conduct research on causes of amphibian population change and malformations; and (4) provide information to resource managers, policy makers, and the public in support of amphibian conservation. The ARMI program will integrate research efforts of USGS, other Federal, and non-federal herpetologists, hydrologists, and geographers across the Nation. ARMI will conduct a small number (~20) of intensive research efforts (for example, studies linking amphibian population changes to hydrologic conditions) and a larger number (~50) of more generalized inventory and monitoring studies encompassing broader areas such as NPS units. ARMI will coordinate with and try to augment other amphibian inventory studies such as the National Amphibian Atlas and the North American Amphibian Monitoring Program. ARMI will develop and test protocols for the standardized collection of amphibian data and provide a centrally managed database designed to simplify data entry, retrieval, and analysis. ARMI pilot projects are underway at locations across the US.

  16. Intact capture of hypervelocity projectiles.

    PubMed

    Tsou, P

    1990-01-01

    The ability to capture projectiles intact at hypervelocities opens new applications in science and technology that would either not be possible or would be very costly by other means. This capability has been demonstrated in the laboratory for aluminum projectiles of 1.6 mm diameter, captured at 6 km/s, in one unmelted piece, and retaining up to 95% of the original mass. Furthermore, capture was accomplished passively using microcellular underdense polymer foam. Another advantage of capturing projectiles in an underdense medium is the ability of such a medium to preserve a record of the projectile's original velocity components of speed and direction. A survey of these experimental results is described in terms of a dozen parameters which characterize the amount of capture and the effect on the projectile due to different capture media. PMID:11538362

  17. Multi-level detection of toxic stress in the mudpuppy (amphibian, salamander)

    SciTech Connect

    Gendron, A.D.; Fortin, R.; Hontela, A.; Bishop, C.A.; Van Der Kraak, G.

    1994-12-31

    Worldwide reports of declining amphibian populations highlight the need for ecotoxicological research on amphibians. The authors have investigated the response to toxic stress in the mudpuppy. Sites (N = 9) along mixed pollution gradients in the St. Lawrence/Ottawa Rivers systems were sampled on two consecutive winters (1992-93). Elevated concentrations of organochlorine pesticides, PCBs, and PCDFs detected in female gonads at the most contaminated sites, led the investigation toward signs of reproductive dysfunction. High levels of skeletal deformities were observed in the most polluted group where mudpuppies were found significantly more at risk to develop limb defects than at the reference site. The frequencies of terata, including oligodactyly and polydactyly, significantly increased with the intensity of exposure to recognized teratogens, in the St. Lawrence River system. The finding of deformities in adults could signal a more important impact during early life stages. The shift toward older t the most impacted site suggest a decrease in recruitment, that is consistent with lower survival of embryos developing under a toxic stress. Among site differences in other indicators of reproductive performance such as fecundity, gonado-somatic indices, circulating levels of 17{beta}-estradiol, testosterone, and corticosterone in females with vitellogenic eggs, were not detected.

  18. Rapid Response to Evaluate the Presence of Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) and Ranavirus in Wild Amphibian Populations in Madagascar

    PubMed Central

    Kolby, Jonathan E.; Smith, Kristine M.; Ramirez, Sara D.; Rabemananjara, Falitiana; Pessier, Allan P.; Brunner, Jesse L.; Goldberg, Caren S.; Berger, Lee; Skerratt, Lee F.

    2015-01-01

    We performed a rapid response investigation to evaluate the presence and distribution of amphibian pathogens in Madagascar following our identification of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranavirus in commercially exported amphibians. This targeted risk-based field surveillance program was conducted from February to April 2014 encompassing 12 regions and 47 survey sites. We simultaneously collected amphibian and environmental samples to increase survey sensitivity and performed sampling both in wilderness areas and commercial amphibian trade facilities. Bd was not detected in any of 508 amphibian skin swabs or 68 water filter samples, suggesting pathogen prevalence was below 0.8%, with 95% confidence during our visit. Ranavirus was detected in 5 of 97 amphibians, including one adult Mantidactylus cowanii and three unidentified larvae from Ranomafana National Park, and one adult Mantidactylus mocquardi from Ankaratra. Ranavirus was also detected in water samples collected from two commercial amphibian export facilities. We also provide the first report of an amphibian mass-mortality event observed in wild amphibians in Madagascar. Although neither Bd nor ranavirus appeared widespread in Madagascar during this investigation, additional health surveys are required to disentangle potential seasonal variations in pathogen abundance and detectability from actual changes in pathogen distribution and rates of spread. Accordingly, our results should be conservatively interpreted until a comparable survey effort during winter months has been performed. It is imperative that biosecurity practices be immediately adopted to limit the unintentional increased spread of disease through the movement of contaminated equipment or direct disposal of contaminated material from wildlife trade facilities. The presence of potentially introduced strains of ranaviruses suggests that Madagascar's reptile species might also be threatened by disease

  19. Control of cell volume in skeletal muscle.

    PubMed

    Usher-Smith, Juliet A; Huang, Christopher L-H; Fraser, James A

    2009-02-01

    Regulation of cell volume is a fundamental property of all animal cells and is of particular importance in skeletal muscle where exercise is associated with a wide range of cellular changes that would be expected to influence cell volume. These complex electrical, metabolic and osmotic changes, however, make rigorous study of the consequences of individual factors on muscle volume difficult despite their likely importance during exercise. Recent charge-difference modelling of cell volume distinguishes three major aspects to processes underlying cell volume control: (i) determination by intracellular impermeant solute; (ii) maintenance by metabolically dependent processes directly balancing passive solute and water fluxes that would otherwise cause cell swelling under the influence of intracellular membrane-impermeant solutes; and (iii) volume regulation often involving reversible short-term transmembrane solute transport processes correcting cell volumes towards their normal baselines in response to imposed discrete perturbations. This review covers, in turn, the main predictions from such quantitative analysis and the experimental consequences of comparable alterations in extracellular pH, lactate concentration, membrane potential and extracellular tonicity. The effects of such alterations in the extracellular environment in resting amphibian muscles are then used to reproduce the intracellular changes that occur in each case in exercising muscle. The relative contributions of these various factors to the control of cell volume in resting and exercising skeletal muscle are thus described. PMID:19133959

  20. AMPHIBIAN DECLINES AND ENVIRONMENTAL CHANGE IN THE EASTERN "MOJAVE DESERT"

    EPA Science Inventory

    A number of amphibian species historically inhabited sparsely distributed wetlands in the Mojave Desert, USA, habitats that have been dramatically altered or eliminated as a result of human activities. The population status and distribution of amphibians were investigated in a 20...

  1. Amphibian Oasis: Designing and Building a Schoolyard Pond.

    ERIC Educational Resources Information Center

    Gosselin, Heather; Johnson, Bob

    1996-01-01

    Building a pond in a schoolyard is a rewarding way to help boost local populations of amphibians, to increase the natural value of school grounds, and to serve as a locale for observing the life cycles of plants, invertebrates, and amphibians. This article outlines important considerations in designing and building a pond from siting through…

  2. 50 CFR 17.43 - Special rules-amphibians.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 2 2010-10-01 2010-10-01 false Special rules-amphibians. 17.43 Section 17.43 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—amphibians. (a) San Marcos salamander (Eurycea nana). (1) All provisions of § 17.31 apply...

  3. 50 CFR 17.43 - Special rules-amphibians.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 2 2011-10-01 2011-10-01 false Special rules-amphibians. 17.43 Section 17.43 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—amphibians. (a) San Marcos salamander (Eurycea nana). (1) All provisions of § 17.31 apply...

  4. 50 CFR 17.43 - Special rules-amphibians.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 2 2013-10-01 2013-10-01 false Special rules-amphibians. 17.43 Section 17.43 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—amphibians. (a) San Marcos salamander (Eurycea nana). (1) All provisions of § 17.31 apply...

  5. 50 CFR 17.43 - Special rules-amphibians.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 2 2012-10-01 2012-10-01 false Special rules-amphibians. 17.43 Section 17.43 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—amphibians. (a) San Marcos salamander (Eurycea nana). (1) All provisions of § 17.31 apply...

  6. All about Amphibians. Animal Life for Children. [Videotape].

    ERIC Educational Resources Information Center

    2000

    This videotape teaches children about their favorite amphibious creatures, as well as amphibians' nearest cousins--toads, newts, and salamanders. Young students discover how these amazing creatures can live both in and out of water, learn about the amphibious life cycle, and compare the differences between amphibians and reptiles. This videotape…

  7. 50 CFR 17.43 - Special rules-amphibians.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 2 2014-10-01 2014-10-01 false Special rules-amphibians. 17.43 Section 17.43 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR... Special rules—amphibians. (a) San Marcos salamander (Eurycea nana). (1) All provisions of § 17.31 apply...

  8. Amphibians and Reptiles from Paramakatoi and Kato, Guyana

    USGS Publications Warehouse

    MacCulloch, Ross D.; Reynolds, Robert P.

    2012-01-01

    We report the herpetofauna of two neighboring upland locations in west-central Guyana. Twenty amphibian and 24 reptile species were collected. Only 40% of amphibians and 12.5% of reptiles were collected in both locations. This is one of the few collections made at upland (750–800 m) locations in the Guiana Shield.

  9. Incorporating Amphibian Malformations into Inquiry-Based Learning

    ERIC Educational Resources Information Center

    Talley, Brooke L.

    2007-01-01

    Amphibians, a class of vertebrates consisting of frogs and toads, salamanders, and caecilians, are excellent organisms for middle school science students to study because of their ecological significance. Because they exchange oxygen and carbon dioxide through their skin, amphibians absorb any chemicals or substances present in their immediate…

  10. MOJAVE DESERT SPRING: THE AMPHIBIAN POINT OF VIEW

    EPA Science Inventory

    Numerous springs are scattered throughout the eastern Mojave Desert, most of which are concentrated near the bases of mountain ranges. Spring-fed wetlands in this region comprise nearly all the available habitat for amphibians. We surveyed 128 springs for amphibians and habitat t...

  11. Amphibian otoconia in normal and altered gravity

    NASA Astrophysics Data System (ADS)

    Membre, H.; Horn, E.; Dournon, C.

    In vertebrates, the macular end organs of the inner ear are gravity sensing organs. They consist of a neuroepithelium overlaid by a mass of little otoconia or by a single large otolith. These crystallites provide essential informations for orientation and equilibrium. They are mosaic biominerals composed of proteic and inorganic phases. In amphibian adults, the mineral phase is calcium carbonate in the form of calcite or aragonite. The calcitic otoconia with a rhomboedric shape are observed in the utricle of Pleurodeles waltl (urodele amphibian). The aragonitic otoconia with a prismatic or a fusiform shape are observed in the saccule and lagena of Pleurodeles, and in the three gravity-sensing regions of Xenopus laevis (anuran amphibian). The aragonitic biocrystallites are in different proportions depending on the inner ear regions. During the development, in Pleurodeles larvae, we observed that saccular otoconia changed from calcitic to aragonitic form. In Xenopus tadpoles, we observed peculiar otoconia with a rhomboedric-like morphology or a tripartite morphology. We called the latter crystallites cauliflower-like otoconia according to the aspect. We reported our observations performed after two space missions, the experiment Torcol which flew on the French Soyuz taxi flight Perseus to MIR (launch: February 20, 1999; landing: August 28, 1999), and the experiment Aquarius-Xenopus which flew on the French Soyuz taxi flight Andromède to ISS (launch: October 21, 2001; landing: October 31, 2001). After a long journey in space, both calcitic and aragonitic otoconia were altered in Pleurodeles adults. After a short space mission, otoconia with rhomboedric, fusiform or cauliflower-like aspects were observed in Xenopus tadpoles. In these tadpoles, otoconia with rhomboedric aspect were never mixed with the other otoconia types, whereas fusiform otoconia were never alone. Cauliflower-shaped otoconia were alone or associated with fusiform otoconia. The study needs further

  12. Late Cretaceous vicariance in Gondwanan amphibians.

    PubMed

    Van Bocxlaer, Ines; Roelants, Kim; Biju, S D; Nagaraju, J; Bossuyt, Franky

    2006-01-01

    Overseas dispersals are often invoked when Southern Hemisphere terrestrial and freshwater organism phylogenies do not fit the sequence or timing of Gondwana fragmentation. We used dispersal-vicariance analyses and molecular timetrees to show that two species-rich frog groups, Microhylidae and Natatanura, display congruent patterns of spatial and temporal diversification among Gondwanan plates in the Late Cretaceous, long after the presumed major tectonic break-up events. Because amphibians are notoriously salt-intolerant, these analogies are best explained by simultaneous vicariance, rather than by oceanic dispersal. Hence our results imply Late Cretaceous connections between most adjacent Gondwanan landmasses, an essential concept for biogeographic and palaeomap reconstructions. PMID:17183706

  13. Partners in amphibian and reptile conservation 2013 annual report

    USGS Publications Warehouse

    Conrad, Paulette M., (Edited By); Weir, Linda A.; Nanjappa, Priya

    2014-01-01

    Partners in Amphibian and Reptile Conservation (PARC) was established in 1999 to address the widespread declines, extinctions, and range reductions of amphibians and reptiles, with a focus on conservation of taxa and habitats in North America. Amphibians and reptiles are affected by a broad range of human activities, both as incidental effects of habitat alteration and direct effect from overexploitation; these animals are also challenged by the perception that amphibians and reptiles are either dangerous or of little environmental or economic value. However, PARC members understand these taxa are important parts of our natural an cultural heritage and they serve important roles in ecosystems throughout the world. With many amphibians and reptiles classified as threatened with extinction, conservation of these animals has never been more important.

  14. Skeletal stem cells.

    PubMed

    Bianco, Paolo; Robey, Pamela G

    2015-03-15

    Skeletal stem cells (SSCs) reside in the postnatal bone marrow and give rise to cartilage, bone, hematopoiesis-supportive stroma and marrow adipocytes in defined in vivo assays. These lineages emerge in a specific sequence during embryonic development and post natal growth, and together comprise a continuous anatomical system, the bone-bone marrow organ. SSCs conjoin skeletal and hematopoietic physiology, and are a tool for understanding and ameliorating skeletal and hematopoietic disorders. Here and in the accompanying poster, we concisely discuss the biology of SSCs in the context of the development and postnatal physiology of skeletal lineages, to which their use in medicine must remain anchored. PMID:25758217

  15. Proteolytic degradation and deactivation of amphibian skin peptides obtained by electrical stimulation of their dorsal glands.

    PubMed

    Samgina, Tatiana Yu; Tolpina, Miriam I; Hakalehto, Elias; Artemenko, Konstantin A; Bergquist, Jonas; Lebedev, Albert T

    2016-05-01

    Amphibians are among the oldest creatures on our planet. Their only defensive weapon efficient against microorganisms and predators involves their skin secretion. The wide range of biological activities of the peptides in the skin secretion of amphibians makes these compounds rather interesting for generation of prospective pharmaceuticals. The first step in studying these molecules requires their structures to be established. Mass spectrometry is the most powerful tool for this purpose. The sampling and sample preparation stages preceding mass spectrometry experiments appear to be rather crucial. The results obtained here demonstrate that these preparation procedures might lead to partial or complete loss of the bioactive peptides in the secretion. Five minutes in water was enough to completely destroy all of the bioactive peptides in the skin secretion of the marsh frog (Rana ridibunda); even immediate addition of methanol to the water solution of the peptides did not prevent partial destruction. Concerted effort should be directed towards development of the most efficient procedure to keep the secreted peptides intact. Graphical Abstract ᅟ. PMID:26975184

  16. Mechanics of intact bone marrow.

    PubMed

    Jansen, Lauren E; Birch, Nathan P; Schiffman, Jessica D; Crosby, Alfred J; Peyton, Shelly R

    2015-10-01

    The current knowledge of bone marrow mechanics is limited to its viscous properties, neglecting the elastic contribution of the extracellular matrix. To get a more complete view of the mechanics of marrow, we characterized intact yellow porcine bone marrow using three different, but complementary techniques: rheology, indentation, and cavitation. Our analysis shows that bone marrow is elastic, and has a large amount of intra- and inter-sample heterogeneity, with an effective Young׳s modulus ranging from 0.25 to 24.7 kPa at physiological temperature. Each testing method was consistent across matched tissue samples, and each provided unique benefits depending on user needs. We recommend bulk rheology to capture the effects of temperature on tissue elasticity and moduli, indentation for quantifying local tissue heterogeneity, and cavitation rheology for mitigating destructive sample preparation. We anticipate the knowledge of bone marrow elastic properties for building in vitro models will elucidate mechanisms involved in disease progression and regenerative medicine. PMID:26189198

  17. Phylogenetically-Informed Priorities for Amphibian Conservation

    PubMed Central

    Isaac, Nick J. B.; Redding, David W.; Meredith, Helen M.; Safi, Kamran

    2012-01-01

    The amphibian decline and extinction crisis demands urgent action to prevent further large numbers of species extinctions. Lists of priority species for conservation, based on a combination of species’ threat status and unique contribution to phylogenetic diversity, are one tool for the direction and catalyzation of conservation action. We describe the construction of a near-complete species-level phylogeny of 5713 amphibian species, which we use to create a list of evolutionarily distinct and globally endangered species (EDGE list) for the entire class Amphibia. We present sensitivity analyses to test the robustness of our priority list to uncertainty in species’ phylogenetic position and threat status. We find that both sources of uncertainty have only minor impacts on our ‘top 100‘ list of priority species, indicating the robustness of the approach. By contrast, our analyses suggest that a large number of Data Deficient species are likely to be high priorities for conservation action from the perspective of their contribution to the evolutionary history. PMID:22952807

  18. Current extinction rates of reptiles and amphibians

    PubMed Central

    Alroy, John

    2015-01-01

    There is broad concern that a mass extinction of amphibians and reptiles is now underway. Here I apply an extremely conservative Bayesian method to estimate the number of recent amphibian and squamate extinctions in nine important tropical and subtropical regions. The data stem from a combination of museum collection databases and published site surveys. The method computes an extinction probability for each species by considering its sighting frequency and last sighting date. It infers hardly any extinction when collection dates are randomized and it provides underestimates when artificial extinction events are imposed. The method also appears to be insensitive to trends in sampling; therefore, the counts it provides are absolute minimums. Extinctions or severe population crashes have accumulated steadily since the 1970s and 1980s, and at least 3.1% of frog species have already disappeared. Based on these data and this conservative method, the best estimate of the global grand total is roughly 200 extinctions. Consistent with previous results, frog losses are heavy in Latin America, which has been greatly affected by the pathogenic chytrid fungus Batrachochytrium dendrobatidis. Extinction rates are now four orders-of-magnitude higher than background, and at least another 6.9% of all frog species may be lost within the next century, even if there is no acceleration in the growth of environmental threats. PMID:26438855

  19. Current extinction rates of reptiles and amphibians.

    PubMed

    Alroy, John

    2015-10-20

    There is broad concern that a mass extinction of amphibians and reptiles is now underway. Here I apply an extremely conservative Bayesian method to estimate the number of recent amphibian and squamate extinctions in nine important tropical and subtropical regions. The data stem from a combination of museum collection databases and published site surveys. The method computes an extinction probability for each species by considering its sighting frequency and last sighting date. It infers hardly any extinction when collection dates are randomized and it provides underestimates when artificial extinction events are imposed. The method also appears to be insensitive to trends in sampling; therefore, the counts it provides are absolute minimums. Extinctions or severe population crashes have accumulated steadily since the 1970s and 1980s, and at least 3.1% of frog species have already disappeared. Based on these data and this conservative method, the best estimate of the global grand total is roughly 200 extinctions. Consistent with previous results, frog losses are heavy in Latin America, which has been greatly affected by the pathogenic chytrid fungus Batrachochytrium dendrobatidis. Extinction rates are now four orders-of-magnitude higher than background, and at least another 6.9% of all frog species may be lost within the next century, even if there is no acceleration in the growth of environmental threats. PMID:26438855

  20. Fetal adaptations for viviparity in amphibians.

    PubMed

    Wake, Marvalee H

    2015-08-01

    Live-bearing has evolved in all three orders of amphibians--frogs, salamanders, and caecilians. Developing young may be either yolk dependent, or maternal nutrients may be supplied after yolk is resorbed, depending on the species. Among frogs, embryos in two distantly related lineages develop in the skin of the maternal parents' backs; they are born either as advanced larvae or fully metamorphosed froglets, depending on the species. In other frogs, and in salamanders and caecilians, viviparity is intraoviductal; one lineage of salamanders includes species that are yolk dependent and born either as larvae or metamorphs, or that practice cannibalism and are born as metamorphs. Live-bearing caecilians all, so far as is known, exhaust yolk before hatching and mothers provide nutrients during the rest of the relatively long gestation period. The developing young that have maternal nutrition have a number of heterochronic changes, such as precocious development of the feeding apparatus and the gut. Furthermore, several of the fetal adaptations, such as a specialized dentition and a prolonged metamorphosis, are homoplasious and present in members of two or all three of the amphibian orders. At the same time, we know little about the developmental and functional bases for fetal adaptations, and less about the factors that drive their evolution and facilitate their maintenance. PMID:24643944

  1. Amphibian skin may select for rare environmental microbes

    PubMed Central

    Walke, Jenifer B; Becker, Matthew H; Loftus, Stephen C; House, Leanna L; Cormier, Guy; Jensen, Roderick V; Belden, Lisa K

    2014-01-01

    Host-microbe symbioses rely on the successful transmission or acquisition of symbionts in each new generation. Amphibians host a diverse cutaneous microbiota, and many of these symbionts appear to be mutualistic and may limit infection by the chytrid fungus, Batrachochytrium dendrobatidis, which has caused global amphibian population declines and extinctions in recent decades. Using bar-coded 454 pyrosequencing of the 16S rRNA gene, we addressed the question of symbiont transmission by examining variation in amphibian skin microbiota across species and sites and in direct relation to environmental microbes. Although acquisition of environmental microbes occurs in some host-symbiont systems, this has not been extensively examined in free-living vertebrate-microbe symbioses. Juvenile bullfrogs (Rana catesbeiana), adult red-spotted newts (Notophthalmus viridescens), pond water and pond substrate were sampled at a single pond to examine host-specificity and potential environmental transmission of microbiota. To assess population level variation in skin microbiota, adult newts from two additional sites were also sampled. Cohabiting bullfrogs and newts had distinct microbial communities, as did newts across the three sites. The microbial communities of amphibians and the environment were distinct; there was very little overlap in the amphibians' core microbes and the most abundant environmental microbes, and the relative abundances of OTUs that were shared by amphibians and the environment were inversely related. These results suggest that, in a host species-specific manner, amphibian skin may select for microbes that are generally in low abundance in the environment. PMID:24858782

  2. Facility design and associated services for the study of amphibians.

    PubMed

    Browne, Robert K; Odum, R Andrew; Herman, Timothy; Zippel, Kevin

    2007-01-01

    The role of facilities and associated services for amphibians has recently undergone diversification. Amphibians traditionally used as research models adjust well to captivity and thrive with established husbandry techniques. However, it is now necessary to maintain hundreds of novel amphibian species in captive breeding, conservation research, and biomedical research programs. These diverse species have a very wide range of husbandry requirements, and in many cases the ultimate survival of threatened species will depend on captive populations. Two critical factors have emerged in the maintenance of amphibians, stringent quarantine and high-quality water. Because exotic diseases such as chytridiomycosis have devastated both natural and captive populations of amphibians, facilities must provide stringent quarantine. The provision of high-quality water is also essential to maintain amphibian health and condition due to the intimate physiological relationship of amphibians to their aquatic environment. Fortunately, novel technologies backed by recent advances in the scientific knowledge of amphibian biology and disease management are available to overcome these challenges. For example, automation can increase the reliability of quarantine and maintain water quality, with a corresponding decrease in handling and the associated disease-transfer risk. It is essential to build facilities with appropriate nontoxic waterproof materials and to provide quarantined amphibian rooms for each population. Other spaces and services include live feed rooms, quarantine stations, isolation rooms, laboratory space, technical support systems, reliable energy and water supplies, high-quality feed, and security. Good husbandry techniques must include reliable and species-specific management by trained staff members who receive support from the administration. It is possible to improve husbandry techniques for many species by sharing knowledge through common information systems. Overall

  3. Modeling effects of conservation grassland losses on amphibian habitat

    USGS Publications Warehouse

    Mushet, David M.; Neau, Jordan L.; Euliss, Ned H.

    2014-01-01

    Amphibians provide many ecosystem services valued by society. However, populations have declined globally with most declines linked to habitat change. Wetlands and surrounding terrestrial grasslands form habitat for amphibians in the North American Prairie Pothole Region (PPR). Wetland drainage and grassland conversion have destroyed or degraded much amphibian habitat in the PPR. However, conservation grasslands can provide alternate habitat. In the United States, the Conservation Reserve Program (CRP) is the largest program maintaining grasslands on agricultural lands. We used an ecosystem services model (InVEST) parameterized for the PPR to quantify amphibian habitat over a six-year period (2007–2012). We then quantified changes in availability of amphibian habitat under various land-cover scenarios representing incremental losses (10%, 25%, 50%, 75%, and 100%) of CRP grasslands from 2012 levels. The area of optimal amphibian habitat in the four PPR ecoregions modeled (i.e., Northern Glaciated Plains, Northwestern Glaciated Plains, Lake Agassiz Plain, Des Moines Lobe) declined by approximately 22%, from 3.8 million ha in 2007 to 2.9 million ha in 2012. These losses were driven by the conversion of CRP grasslands to croplands, primarily for corn and soybean production. Our modeling identified an additional 0.8 million ha (26%) of optimal amphibian habitat that would be lost if remaining CRP lands are returned to crop production. An economic climate favoring commodity production over conservation has resulted in substantial losses of amphibian habitat across the PPR that will likely continue into the future. Other regions of the world face similar challenges to maintaining amphibian habitats.

  4. [Strategies for Conservation of Endangered Amphibian and Reptile Species].

    PubMed

    Anan'eva, N B; Uteshev, V K; Orlova, N L; Gakhova, E N

    2015-01-01

    Strategies for conservation of endangered amphibian and reptile species are discussed. One-fifth of all vertebrates belongs to the category of "endangered species," and amphibians are first on the list (41%). Every fifth reptile species is in danger of extinction, and insufficient information is characteristic of every other fifth. As has been demonstrated, efficient development of a network of nature conservation areas, cryopreservation, and methods for laboratory breeding and reintroduction play.the key roles in adequate strategies for preservation of amphibians and reptiles. PMID:26638239

  5. Larval nematodes found in amphibians from northeastern Argentina.

    PubMed

    González, C E; Hamann, M I

    2010-11-01

    Five species of amphibians, Leptodactylus podicipinus, Scinax acuminatus, S. nasicus, Rhinella fernandezae and Pseudis paradoxa, were collected in Corrientes province, Argentina and searched for larval nematodes. All larval nematodes were found as cysts in the serous of the stomach of hosts. Were identified one superfamily, Seuratoidea; one genus, Spiroxys (Superfamily Gnathostomatoidea) and one family, Rhabdochonidae (Superfamily Thelazioidea). We present a description and illustrations of these taxa. These nematodes have an indirect life cycle and amphibians are infected by consuming invertebrate, the intermediate hosts. The genus Spiroxys and superfamily Seuratoidea were reported for the first time for Argentinean amphibians. PMID:21180919

  6. Amphibian fertilization and development in microgravity

    NASA Technical Reports Server (NTRS)

    Souza, K. A.; Black, S. D.

    1985-01-01

    An experiment investigating the effects of gravity on embryonic development in amphibians is proposed. The planned procedures for the preparation of the frog eggs for launching in the Space Shuttle, for the injection of the eggs with gonadotropin, for the insertion of the eggs into egg chambers, for the storage of one of the chambers in a microgravity area and the second into a centrifuge, and for the fertilization of the eggs are described. The later organogenesis, swimming behavior, cytoplasmic components, cellular formation, neural plate and archenteron expansion, and allometry and expansion of the organ systems will be examined. Normal morphology for embryos and tadpoles developing at microgravity and the formation of the neural plate opposite the sperm entry point meridian are predicted.

  7. Hot bodies protect amphibians against chytrid infection in nature

    PubMed Central

    Rowley, Jodi J. L.; Alford, Ross A.

    2013-01-01

    Environmental context strongly affects many host-pathogen interactions, but the underlying causes of these effects at the individual level are usually poorly understood. The amphibian chytrid fungus has caused amphibian population declines and extinctions in many parts of the world. Many amphibian species that have declined or have been extirpated by the pathogen in some environments coexist with it in others. Here we show that in three species of rainforest frogs in nature, individuals' probability of infection by the amphibian chytrid fungus was strongly related to their thermal history. Individuals' probability of infection declined rapidly as they spent more time above the pathogen's upper optimum temperature. This relationship can explain population-level patterns of prevalence in nature, and suggests that natural or artificial selection for higher thermal preferences could reduce susceptibility to this pathogen. Similar individual-level insights could improve our understanding of environmental context-dependence in other diseases. PMID:23519020

  8. Trends in amphibian occupancy in the United States.

    PubMed

    Adams, Michael J; Miller, David A W; Muths, Erin; Corn, Paul Stephen; Grant, Evan H Campbell; Bailey, Larissa L; Fellers, Gary M; Fisher, Robert N; Sadinski, Walter J; Waddle, Hardin; Walls, Susan C

    2013-01-01

    Though a third of amphibian species worldwide are thought to be imperiled, existing assessments simply categorize extinction risk, providing little information on the rate of population losses. We conducted the first analysis of the rate of change in the probability that amphibians occupy ponds and other comparable habitat features across the United States. We found that overall occupancy by amphibians declined 3.7% annually from 2002 to 2011. Species that are Red-listed by the International Union for Conservation of Nature (IUCN) declined an average of 11.6% annually. All subsets of data examined had a declining trend including species in the IUCN Least Concern category. This analysis suggests that amphibian declines may be more widespread and severe than previously realized. PMID:23717602

  9. Checklist of Helminth parasites of Amphibians from South America.

    PubMed

    Campião, Karla Magalhães; Morais, Drausio Honorio; Dias, Olívia Tavares; Aguiar, Aline; Toledo, Gislayne De Melo; Tavares, Luiz Eduardo Roland; Da Silva, Reinaldo José

    2014-01-01

    Parasitological studies on helminths of amphibians in South America have increased in the past few years. Here, we present a list with summarized data published on helminths of South American amphibians from 1925 to 2012, including a list of helminth parasites, host species, and geographic records. We found 194 reports of helminths parasitizing 185 amphibian species from eleven countries: Argentina, Brazil, Chile, Colombia, Equador, French Guyana, Guyana, Paraguay, Peru, Uruguay and Venezuela. Helminth biodiversity includes 278 parasite species of the groups Acanthocephala, Nematoda, Cestoda, Monogenea and Trematoda. A list of helminth parasite species per host, and references are also presented. This contribution aims to document the biodiversity of helminth parasites in South American amphibians, as well as identify gaps in our knowledge, which in turn may guide subsequent studies.  PMID:25082165

  10. AmphibiaChina: an online database of Chinese Amphibians.

    PubMed

    Che, Jing; Wang, Kai

    2016-01-18

    AmphibiaChina, an open-access, web-based database, is designed to provide comprehensive and up-to-date information on Chinese amphibians. It offers an integrated module with six major sections. Compared to other known databases including AmphibiaWeb and Amphibian Species of the World, AmphibiaChina has the following new functions: (1) online species identification based on DNA barcode sequences; (2) comparisons and discussions of different major taxonomic systems; and (3) phylogenetic progress on Chinese amphibians. This database offers a window for the world to access available information of Chinese amphibians. AmphibiaChina with its Chinese version can be accessed at http://www.amphibiachina.org. PMID:26828034

  11. Twenty years of ISAREN: an amphibian biologist in Wonderland.

    PubMed

    Kikuyama, Sakae

    2010-09-01

    The 6th International Symposium on Amphibian and Reptilian Endocrinology and Neurobiology (ISAREN), the former International Symposium on Amphibian Endocrinology (ISAE), was recently held in Berlin. ISAREN developed from two symposia on amphibian biology held in European countries in 1988-1990. In this article, the history of ISAREN was briefly stated. In addition, some of the topics of our researches carried out in collaboration with several groups, using various amphibian species during the past 20 years and/or presented in the past symposia were reviewed. The topics included the discovery of pancreatic chitinase, involvement of growth hormone in vitellogenin synthesis, changes of ANF-like immunoreactivity in the frogs sent into the space, discovery of a peptide sex-pheromone, origin of the epithelial pituitary, and hypothalamic regulation of thyroid-stimulating hormone. PMID:20138045

  12. CHARACTERIZATION OF RELATIVE SENSITIVITY OF AMPHIBIANS TO ULTRAVIOLET RADIATION

    EPA Science Inventory

    Different studies have demonstrated that solar ultraviolet (UV) radiation can adversely affect survival and development of embryonic and larval amphibians. However, because of among-laboratory variations in exposure profiles (artificial vs. natural sunlight; natural sunlight at d...

  13. CHARACTERIZATION OF RELATIVE SENSITIVITY OF AMPHIBIANS TO ULTRA VIOLET RADIATION

    EPA Science Inventory

    Different studies have demonstrated that solar ultraviolet (UV) radiation can adversely affect survival and development of embryonic and larval amphibians. However, because of among-laboratory variations in exposure profiles (artificial vs. natural sunlight; natural sunlight at d...

  14. Trends in amphibian occupancy in the United States

    USGS Publications Warehouse

    Adams, Michael J.; Miller, David A.W.; Muths, Erin; Corn, Paul Stephen; Grant, Evan H. Campbell; Bailey, Larissa L.; Fellers, Gary M.; Fisher, Robert N.; Sadinski, Walter J.; Waddle, Hardin; Walls, Susan C.

    2013-01-01

    Though a third of amphibian species worldwide are thought to be imperiled, existing assessments simply categorize extinction risk, providing little information on the rate of population losses. We conducted the first analysis of the rate of change in the probability that amphibians occupy ponds and other comparable habitat features across the United States. We found that overall occupancy by amphibians declined 3.7% annually from 2002 to 2011. Species that are Red-listed by the International Union for Conservation of Nature (IUCN) declined an average of 11.6% annually. All subsets of data examined had a declining trend including species in the IUCN Least Concern category. This analysis suggests that amphibian declines may be more widespread and severe than previously realized.

  15. Invasive and introduced reptiles and amphibians: Chapter 28

    USGS Publications Warehouse

    Reed, Robert N.; Krysko, Kenneth L.

    2014-01-01

    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.

  16. Ambient UV-B radiation causes deformities in amphibian embryos

    USGS Publications Warehouse

    Blaustein, A.R.; Kiesecker, J.M.; Chivers, D.P.; Anthony, R.G.

    1997-01-01

    There has been a great deal of recent attention on the suspected increase in amphibian deformities. However, most reports of amphibian deformities have been anecdotal, and no experiments in the field under natural conditions have been performed to investigate this phenomenon. Under laboratory conditions, a variety of agents can induce deformities in amphibians. We investigated one of these agents, UV-B radiation, in field experiments, as a cause for amphibian deformities. We monitored hatching success and development in long-toed salamanders under UV-B shields and in regimes that allowed UV-B radiation. Embryos under UV-B shields had a significantly higher hatching rate and fewer deformities, and developed more quickly than those exposed to UV-B. Deformities may contribute directly to embryo mortality, and they may affect an individual's subsequent survival after hatching.

  17. Metabolism of pesticides after dermal exposure to amphibians

    EPA Science Inventory

    Understanding how pesticide exposure to non-target species influences toxicity is necessary to accurately assess the ecological risks these compounds pose. Aquatic, terrestrial, and arboreal amphibians are often exposed to pesticides during their agricultural application resultin...

  18. An alternative framework for responding to the amphibian crisis

    USGS Publications Warehouse

    Muths, Erin L.; Fisher, Robert N.

    2015-01-01

    Volumes of data illustrate the severity of the crisis affecting amphibians, where > 32% of amphibians worldwide are threatened with declining populations. Although there have been isolated victories, the current approach to the issue is unsuccessful. We suggest that a radically different approach, something akin to human emergency response management (i.e. the Incident Command System), is one alternative to addressing the inertia and lack of cohesion in responding to amphibian issues. We acknowledge existing efforts and the useful research that has been conducted, but we suggest that a change is warranted and that the identification of a new amphibian chytrid provides the impetus for such a change. Our goal is to recognize that without a centralized effort we (collectively) are likely to fail in responding to this challenge.

  19. AmphibiaChina: an online database of Chinese Amphibians

    PubMed Central

    CHE, Jing; WANG, Kai

    2016-01-01

    AmphibiaChina, an open-access, web-based database, is designed to provide comprehensive and up-to-date information on Chinese amphibians. It offers an integrated module with six major sections. Compared to other known databases including AmphibiaWeb and Amphibian Species of the World, AmphibiaChina has the following new functions: (1) online species identification based on DNA barcode sequences; (2) comparisons and discussions of different major taxonomic systems; and (3) phylogenetic progress on Chinese amphibians. This database offers a window for the world to access available information of Chinese amphibians. AmphibiaChina with its Chinese version can be accessed at http://www.amphibiachina.org. PMID:26828034

  20. ALIEN SPECIES: THEIR ROLE IN AMPHIBIAN POPULATION DECLINES AND RESTORATION

    EPA Science Inventory

    Alien species (also referred to as exotic, invasive, introduced, or normative species) have been implicated as causal agents in population declines of many amphibian species. Herein, we evaluate the relative contributions of alien species and other factors in adversely affecting ...

  1. Global amphibian declines: perspectives from the United States and beyond

    USGS Publications Warehouse

    Densmore, Christine L.

    2011-01-01

    Over recent decades, amphibians have experienced population declines, extirpations and species-level extinctions at an alarming rate. Numerous potential etiologies for amphibian declines have been postulated including climate and habitat degradation. Other potential anthropogenic causes including overexploitation and the frequent introductions of invasive predatory species have also been blamed for amphibian declines. Still other underlying factors may include infectious diseases caused by the chytrid fungus Batrachochytrium dendrobatidis, pathogenic viruses (Ranavirus), and other agents. It is nearly certain that more than one etiology is to blame for the majority of the global amphibian declines, and that these causal factors include some combination of climatological or physical habitat destabilization and infectious disease, most notably chytridiomycosis. Scientific research efforts are aimed at elucidating these etiologies on local, regional, and global scales that we might better understand and counteract the driving forces behind amphibian declines. Conservation efforts as outlined in the Amphibian Conservation Action Plan of 2005 are also being made to curtail losses and prevent further extinctions wherever possible.

  2. Predation of Ladybird Beetles (Coleoptera: Coccinellidae) by Amphibians

    PubMed Central

    Sloggett, John J.

    2012-01-01

    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. PMID:26466621

  3. Monitoring amphibians in Great Smoky Mountains National Park

    USGS Publications Warehouse

    Dodd, C. Kenneth, Jr.

    2003-01-01

    This report provides an overview of the Park’s amphibians, the factors affecting their distribution, a review of important areas of biodiversity, and a summary of amphibian life history in the Southern Appalachians. In addition, survey techniques are described as well as examples of how the techniques are set up, a critique of what the results tell the observer, and a discussion of the limitations of the techniques and the data. The report reviews considerations for site selection, outlines steps for biosecurity and for processing diseased or dying animals, and provides resource managers with a decision tree on how to monitor the Park’s amphibians based on different levels of available resources. It concludes with an extensive list of references for inventorying and monitoring amphibians. USGS and Great Smoky Mountains National Park biologists need to establish cooperative efforts and training to ensure that congressionally mandated amphibian surveys are performed in a statistically rigorous and biologically meaningful manner, and that amphibian populations on Federal lands are monitored to ensure their long-term survival. The research detailed in this report will aid these cooperative efforts.

  4. Global patterns of diversification in the history of modern amphibians.

    PubMed

    Roelants, Kim; Gower, David J; Wilkinson, Mark; Loader, Simon P; Biju, S D; Guillaume, Karen; Moriau, Linde; Bossuyt, Franky

    2007-01-16

    The fossil record of modern amphibians (frogs, salamanders, and caecilians) provides no evidence for major extinction or radiation episodes throughout most of the Mesozoic and early Tertiary. However, long-term gradual diversification is difficult to reconcile with the sensitivity of present-day amphibian faunas to rapid ecological changes and the incidence of similar environmental perturbations in the past that have been associated with high turnover rates in other land vertebrates. To provide a comprehensive overview of the history of amphibian diversification, we constructed a phylogenetic timetree based on a multigene data set of 3.75 kb for 171 species. Our analyses reveal several episodes of accelerated amphibian diversification, which do not fit models of gradual lineage accumulation. Global turning points in the phylogenetic and ecological diversification occurred after the end-Permian mass extinction and in the late Cretaceous. Fluctuations in amphibian diversification show strong temporal correlation with turnover rates in amniotes and the rise of angiosperm-dominated forests. Approximately 86% of modern frog species and >81% of salamander species descended from only five ancestral lineages that produced major radiations in the late Cretaceous and early Tertiary. This proportionally late accumulation of extant lineage diversity contrasts with the long evolutionary history of amphibians but is in line with the Tertiary increase in fossil abundance toward the present. PMID:17213318

  5. Endemic skeletal fluorosis

    PubMed Central

    Teotia, M.; Teotia, S. P. S.; Kunwar, K. B.

    1971-01-01

    Endemic skeletal fluorosis is described in 6 children aged 11 or over. Four cases were crippled with severe deformities in the spine, hips, and knees. All showed positive phosphorus, magnesium, and nitrogen balances and excessively positive calcium balances. The skeletal x-rays, histology, and chemical composition of the bones revealed diagnostic changes in each case. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5 PMID:5118057

  6. Histological image data of limb skeletal tissue from larval and adult Ambystoma mexicanum.

    PubMed

    McCusker, Catherine D; Diaz-Castillo, Carlos; Sosnik, Julian; Phan, Anne; Gardiner, David M

    2016-09-01

    The data presented in this article are related to the article entitled "Cartilage and bone cells do not participate in skeletal regeneration in Ambystoma mexicanum limbs" [1]. Here we present image data of the post-embryonic development of the forelimb skeletal tissue of Ambystoma Mexicanum. Histological staining was performed on sections from the intact limbs of young (6.5 cm) and old (25 cm) animals, and on dissected skeletal tissues (cartilage, bone, and periosteum) from these animals. PMID:27547798

  7. Lymphocyte development in fish and amphibians.

    PubMed

    Hansen, J D; Zapata, A G

    1998-12-01

    Recently, molecular markers such as recombination activating genes (RAG), terminal deoxynucleotidyl transferase (TdT), stem cell leukemia hematopoietic transcription factor (SCL), Ikaros and gata-binding protein (Gata)-family members have been isolated and characterized from key lower vertebrates, adding to our growing knowledge of lymphopoiesis in ectotherms. In all gnathostomes there appear to be two main embryonic locations derived from the early mesoderm, both intra- and extraembryonic, which contribute to primitive and definitive hematopoiesis based upon their differential expression of SCL, Gata-1, Gata-2 and myeloblastosis oncogene (c-myb). In teleosts, a unique intraembryonic location for hematopoietic stem cells termed the intermediate cell mass (ICM) of Oellacher appears to be responsible for primitive or definitive hematopoiesis depending upon the species being investigated. In Xenopus, elegant grafting studies in combination with specific molecular markers has led to a better definition of the roles that ventral blood islands and dorsal lateral plate play in amphibian hematopoiesis, that of primitive and definitive lymphopoiesis. After the early embryonic contribution to hematopoiesis, specialized tissues must assume the role of providing the proper microenvironment for T and B-lymphocyte development from progenitor stem cells. In all gnathostomes, the thymus is the major site for T-cell maturation as evidenced by strong expression of developmental markers such as Ikaros, Rag and TdT plus expression of T-cell specific markers such as T-cell receptor beta and lck. In this respect, several zebrafish mutants have provided new insights on the development of the thymopoietic environment. On the other hand, the sites for B-cell lymphopoiesis are less clear among the lower vertebrates. In elasmobranchs, the spleen, Leydig's organ and the spiral valve may all contribute to B-cell development, although pre-B cells have yet to be fully addressed in fish. In

  8. Calcium transients in isolated amphibian skeletal muscle fibres: detection with aequorin.

    PubMed Central

    Blinks, J R; Rüdel, R; Taylor, S R

    1978-01-01

    1. Single twitch muscle fibres isolated from frogs and toads were microinjected with the Ca2+-sensitive bioluminescent protein aequorin. The fibres contracted normally and emitted flashes of light (aequorin responses) in response to stimulation for many hours thereafter. 2. No luminescence was detected from healthy fibres at rest. 3. The aequorin diffused from the site of injection at a rate consistent with a diffusion coefficient of 5 x 10(-8) cm2/sec. 4. During trains of isometric contractions there was a progressive reduction in both the amplitude and the rate of decline of the aequorin response, an observation consistent with the theory that Ca is redistributed from sites of release to sites of sequestration under such circumstances. 5. In isometric tetani light emission continued to rise long after the plateau of force had been achieved. This and the fact that the amplitude of the tetanic aequorin response increased steeply with increasing stimulus frequency suggest that in tetani the sarcoplasmic [Ca2+] may normally be above the level required to saturate the contractile apparatus. 6. Both in twitches and in tetani the amplitude of the aequorin response increased slightly and then decreased substantially as the fibre was stretched progressively beyond slack length. 7. In potassium contractures the luminescent and mechanical responses first became detectable at about the same [K+], but for equivalent force luminescence was less intense than in twitches. The aequorin response was biphasic in solutions of high [K+]. 8. Exposure of the fibre to Ca2+-free solutions had no influence on either the mechanical or the luminescent responses in twitches. In Ca2+-free solutions tetanic aequorin responses tended not to be maintained as well as normally, suggesting that intracellular Ca stores do become somewhat depleted. 9. In twitches the amplitude of the aequorin response probably reflects the amount of Ca2+ liberated into the cytoplasm rather than a [Ca2+] in equilibrium with the myofilaments. Changes in the rate of decay of the aequorin response may reflect changes in the rate of Ca sequestration by the sarcoplasmic reticulum. 10. In K+-contractures and during the plateaus of tetani the aequorin signal changes slowly enough so that it seems unlikely that substantial gradients of [Ca2+] exist at the sarcomere level. Under such circumstances the amplitude of the aequorin response probably does reflect the [Ca2+] in equilibrium with the myofilaments. Images Plate 1 PMID:306438

  9. Translocations of amphibians: Proven management method or experimental technique

    USGS Publications Warehouse

    Seigel, Richard A.; Dodd, C. Kenneth, Jr.

    2002-01-01

    In an otherwise excellent review of metapopulation dynamics in amphibians, Marsh and Trenham (2001) make the following provocative statements (emphasis added): If isolation effects occur primarily in highly disturbed habitats, species translocations may be necessary to promote local and regional population persistence. Because most amphibians lack parental care, they areprime candidates for egg and larval translocations. Indeed, translocations have already proven successful for several species of amphibians. Where populations are severely isolated, translocations into extinct subpopulations may be the best strategy to promote regional population persistence. We take issue with these statements for a number of reasons. First, the authors fail to cite much of the relevant literature on species translocations in general and for amphibians in particular. Second, to those unfamiliar with current research in amphibian conservation biology, these comments might suggest that translocations are a proven management method. This is not the case, at least in most instances where translocations have been evaluated for an appropriate period of time. Finally, the authors fail to point out some of the negative aspects of species translocation as a management method. We realize that Marsh and Trenham's paper was not concerned primarily with translocations. However, because Marsh and Trenham (2001) made specific recommendations for conservation planners and managers (many of whom are not herpetologists or may not be familiar with the pertinent literature on amphibians), we believe that it is essential to point out that not all amphibian biologists are as comfortable with translocations as these authors appear to be. We especially urge caution about advocating potentially unproven techniques without a thorough review of available options.

  10. Developments in amphibian captive breeding and reintroduction programs.

    PubMed

    Harding, Gemma; Griffiths, Richard A; Pavajeau, Lissette

    2016-04-01

    Captive breeding and reintroduction remain high profile but controversial conservation interventions. It is important to understand how such programs develop and respond to strategic conservation initiatives. We analyzed the contribution to conservation made by amphibian captive breeding and reintroduction since the launch of the International Union for Conservation of Nature (IUCN) Amphibian Conservation Action Plan (ACAP) in 2007. We assembled data on amphibian captive breeding and reintroduction from a variety of sources including the Amphibian Ark database and the IUCN Red List. We also carried out systematic searches of Web of Science, JSTOR, and Google Scholar for relevant literature. Relative to data collected from 1966 to 2006, the number of species involved in captive breeding and reintroduction projects increased by 57% in the 7 years since release of the ACAP. However, there have been relatively few new reintroductions over this period; most programs have focused on securing captive-assurance populations (i.e., species taken into captivity as a precaution against extinctions in the wild) and conservation-related research. There has been a shift to a broader representation of frogs, salamanders, and caecilians within programs and an increasing emphasis on threatened species. There has been a relative increase of species in programs from Central and South America and the Caribbean, where amphibian biodiversity is high. About half of the programs involve zoos and aquaria with a similar proportion represented in specialist facilities run by governmental or nongovernmental agencies. Despite successful reintroduction often being regarded as the ultimate milestone for such programs, the irreversibility of many current threats to amphibians may make this an impractical goal. Instead, research on captive assurance populations may be needed to develop imaginative solutions to enable amphibians to survive alongside current, emerging, and future threats. PMID

  11. Energy and water in aestivating amphibians.

    PubMed

    Carvalho, José E; Navas, Carlos A; Pereira, Isabel C

    2010-01-01

    The physiological mechanisms, behavioral adjustments, and ecological associations that allow animal species to live in extreme environments have evoked the attention of many zoologists. Often, extreme environments are defined as those believed to be limiting to life in terms of water, energetic availability, and temperature. These three elements seem extreme in a number of arid and semi-arid settings that even so have been colonized by amphibians. Because this taxon is usually seen as the quintessential water-dependent ectotherm tetrapods, their presence in a number of semi-arid environments poses a number of intriguing questions regarding microhabitat choice and physiological plasticity, particularly regarding the ecological and physiological correlates of behaviors granting avoidance of the harshest conditions of semi-arid environments. Such avoidance states, generally associated to the concept of aestivation, are currently seen as a diverse and complex phenomena varying from species to species and involving numerous behavioral and metabolic adjustments that enhance survival during the drought. This chapter reviews the physiological ecology of anuran aestivation, mainly from the perspective of water and energy balance. PMID:20069408

  12. Mechanics of Blastopore Closure during Amphibian Gastrulation

    PubMed Central

    Feroze, Rafey; Shawky, Joseph H.; von Dassow, Michelangelo; Davidson, Lance A.

    2014-01-01

    Blastopore closure in the amphibian embryo involves large scale tissue reorganization driven by physical forces. These forces are tuned to generate sustained blastopore closure throughout the course of gastrulation. We describe the mechanics of blastopore closure at multiple scales and in different regions around the blastopore by characterizing large scale tissue deformations, cell level shape change and subcellular F-actin organization and by measuring tissue force production and structural stiffness of the blastopore during gastrulation. We find that the embryo generates a ramping magnitude of force until it reaches a peak force on the order of 0.5 μ Newtons. During this time course, the embryo also stiffens 1.5 fold. Strain rate mapping of the dorsal, ventral and lateral epithelial cells proximal to the blastopore reveals changing patterns of strain rate throughout closure. Cells dorsal to the blastopore, which are fated to become neural plate ectoderm, are polarized and have straight boundaries. In contrast, cells lateral and ventral to the blastopore are less polarized and have tortuous cell boundaries. The F-actin network is organized differently in each region with the highest percentage of alignment occurring in the lateral region. Interestingly F-actin was consistently oriented toward the blastopore lip in dorsal and lateral cells, but oriented parallel to the lip in ventral regions. Cell shape and F-actin alignment analyses reveal different local mechanical environments in regions around the blastopore, which was reflected by the strain rate maps. PMID:25448691

  13. Incentive or Habit Learning in Amphibians?

    PubMed Central

    Muzio, Rubén N.; Pistone Creydt, Virginia; Iurman, Mariana; Rinaldi, Mauro A.; Sirani, Bruno; Papini, Mauricio R.

    2011-01-01

    Toads (Rhinella arenarum) received training with a novel incentive procedure involving access to solutions of different NaCl concentrations. In Experiment 1, instrumental behavior and weight variation data confirmed that such solutions yield incentive values ranging from appetitive (deionized water, DW, leading to weight gain), to neutral (300 mM slightly hypertonic solution, leading to no net weight gain or loss), and aversive (800 mM highly hypertonic solution leading to weight loss). In Experiment 2, a downshift from DW to a 300 mM solution or an upshift from a 300 mM solution to DW led to a gradual adjustment in instrumental behavior. In Experiment 3, extinction was similar after acquisition with access to only DW or with a random mixture of DW and 300 mM. In Experiment 4, a downshift from DW to 225, 212, or 200 mM solutions led again to gradual adjustments. These findings add to a growing body of comparative evidence suggesting that amphibians adjust to incentive shifts on the basis of habit formation and reorganization. PMID:22087217

  14. A review of the role of contaminants in amphibian declines

    USGS Publications Warehouse

    Sparling, D.W.

    2003-01-01

    CONCLUSIONS--Although there are no published studies that demonstrate beyond all doubt that contaminants are involved in long term population declines of amphibians, there is ample evidence and reason to encourage active research and concern about effects. Many contaminants are lethal to amphibians at environmentally realistic concentrations. Acute mortality from these compounds may be difficult to detect because investigators would have to be present shortly after exposures. Chronic mortality may be masked by metapopulation phenomena so that areas that serve as population sinks may be repeatedly recolonized and difficult to identify. Metapopulation dynamics also make it more difficult to define discrete populations. Contaminants also have many sublethal effects on behavior, energetics, malformations, and diverse effects on physiological pathways which, by themselves might not lead to overt death but could alter reproduction or interact with other factors to result in gradual declines in populations. Scientific understanding of these interactions, and of the ecotoxicology of amphibians in general is far behind what is known about birds, fish, and mammals, and research is desperately needed in this area. Some specific suggestions for critically needed research include: (1) Determination of lethal concentrations of common contaminants - pesticides, PAHs, metals--under environmentally realistic conditions of light, temperature, and water chemistry. (2) Better understanding of the effects of long term (weeks, months), low- concentration exposure of persistent pesticides and stable contaminants on amphibians. (3) Development and refinement of bioindicators in amphibians to use in monitoring and screening for potential effects of contaminants in declining amphibian populations. (4) Further studies on the interaction between contaminants and disease agents including immunosuppression in amphibians. (5) Additional research on the interaction between ultraviolet radiation

  15. Amphibian populations in the terrestrial environment: Is there evidence of declines of terrestrial forest amphibians in northwestern California?

    USGS Publications Warehouse

    Welsh, H.H., Jr.; Fellers, G.M.; Lind, A.J.

    2007-01-01

    Amphibian declines have been documented worldwide; however the vast majority are species associated with aquatic habitats. Information on the status and trends of terrestrial amphibians is almost entirely lacking. Here we use data collected across a 12-yr period (sampling from 1984-86 and from 1993-95) to address the question of whether evidence exists for declines among terrestrial amphibians in northwestern California forests. The majority of amphibians, both species and relative numbers, in these forests are direct-developing salamanders of the family Plethodontidae. We examined amphibian richness and evenness, and the relative abundances of the four most common species of plethodontid salamanders. We examined evidence of differences between years in two ecological provinces (coastal and interior) and across young, mature, and late seral forests and with reference to a moisture gradient from xeric to hydric within late seral forests. We found evidence of declines in species richness across years on late seral mesic stands and in the coastal ecological province, but these differences appeared to be caused by differences in the detection of rarer species, rather than evidence of an overall pattern. We also found differences among specific years in numbers of individuals of the most abundant species, Ensatina eschscholtzii, but these differences also failed to reflect a consistent pattern of declines between the two decadal sample periods. Results showing differences in richness, evenness, and relative abundances along both the seral and moisture continua were consistent with previous research. Overall, we found no compelling evidence of a downward trend in terrestrial plethodontid salamanders. We believe that continued monitoring of terrestrial salamander populations is important to understanding mechanisms of population declines in amphibian species. Copyright 2007 Society for the Study of Amphibians and Reptiles.

  16. Investigating the Influence of Environmental Factors on Pesticide Exposure in Amphibians

    EPA Science Inventory

    Environmental factors such as temporal weather patterns and soil characterization coupled with pesticide application rates are known to influence exposure and subsequent absorption of these compounds in amphibians. Amphibians are a unique class of vertebrates due to their varied ...

  17. Advective and diffusive dermal processes for estimating terrestrial amphibian pesticide exposure

    EPA Science Inventory

    Background/Question/Methods Dermal exposure presents a potentially significant but understudied route for pesticide uptake in terrestrial amphibians. Historically, evaluation of pesticide risk to both amphibians and reptiles has been achieved by comparing ingestion and inhalat...

  18. The cause of global amphibian declines: a developmental endocrinologist's perspective.

    PubMed

    Hayes, T B; Falso, P; Gallipeau, S; Stice, M

    2010-03-15

    Greater than 70% of the world's amphibian species are in decline. We propose that there is probably not a single cause for global amphibian declines and present a three-tiered hierarchical approach that addresses interactions among and between ultimate and proximate factors that contribute to amphibian declines. There are two immediate (proximate) causes of amphibian declines: death and decreased recruitment (reproductive failure). Although much attention has focused on death, few studies have addressed factors that contribute to declines as a result of failed recruitment. Further, a great deal of attention has focused on the role of pathogens in inducing diseases that cause death, but we suggest that pathogen success is profoundly affected by four other ultimate factors: atmospheric change, environmental pollutants, habitat modification and invasive species. Environmental pollutants arise as likely important factors in amphibian declines because they have realized potential to affect recruitment. Further, many studies have documented immunosuppressive effects of pesticides, suggesting a role for environmental contaminants in increased pathogen virulence and disease rates. Increased attention to recruitment and ultimate factors that interact with pathogens is important in addressing this global crisis. PMID:20190117

  19. Role of Antimicrobial Peptides in Amphibian Defense Against Trematode Infection

    PubMed Central

    Calhoun, Dana M.; Woodhams, Doug; Howard, Cierra; LaFonte, Bryan E.; Gregory, Jacklyn R.; Johnson, Pieter T. J.

    2016-01-01

    Antimicrobial peptides (AMPs) contribute to the immune defenses of many vertebrates, including amphibians. As larvae, amphibians are often exposed to the infectious stages of trematode parasites, many of which must penetrate the host’s skin, potentially interacting with host AMPs. We tested the effects of the natural AMPs repertoires on both the survival of trematode infectious stages as well as their ability to infect larval amphibians. All five trematode species exhibited decreased survival of cercariae in response to higher concentrations of adult bullfrog AMPs, but no effect when exposed to AMPs from larval bullfrogs. Similarly, the use of norepinephrine to remove AMPs from larval bullfrogs, Pacific chorus frogs, and gray treefrogs had only weak (gray treefrogs) or non-significant (other tested species) effects on infection success by Ribeiroia ondatrae. We nonetheless observed strong differences in parasite infection as a function of both host stage (first- versus second-year bullfrogs) and host species (Pacific chorus frogs versus gray treefrogs) that were apparently unrelated to AMPs. Taken together, our results suggest that AMPs do not play a significant role in defending larval amphibians against trematode cercariae, but that they could be one mechanism helping to prevent infection of post-metamorphic amphibians, particularly for highly aquatic species. PMID:26911920

  20. Electrolyte depletion and osmotic imbalance in amphibians with chytridiomycosis.

    PubMed

    Voyles, Jamie; Berger, Lee; Young, Sam; Speare, Rick; Webb, Rebecca; Warner, Jeffrey; Rudd, Donna; Campbell, Ruth; Skerratt, Lee F

    2007-09-14

    Mounting evidence implicates the disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis, in global amphibian declines and extinctions. While the virulence of this disease has been clearly demonstrated, there is, as yet, no mechanistic explanation for how B. dendrobatidis kills amphibians. To investigate the pathology of chytridiomycosis, blood samples were collected from uninfected, aclinically infected and clinically diseased amphibians and analyzed for a wide range of biochemical and hematological parameters. Here, we show that green tree frogs Litoria caerulea with severe chytridiomycosis had reduced plasma osmolality, sodium, potassium, magnesium and chloride concentrations. Stable plasma albumin, hematocrit and urea levels indicated that hydration status was unaffected, signifying depletion of electrolytes from circulation rather than dilution due to increased water uptake. We suggest that B. dendrobatidis kills amphibians by disrupting normal epidermal functioning, leading to osmotic imbalance through loss of electrolytes. Determining how B. dendrobatidis kills amphibians is fundamental to understanding the host-pathogen relationship and thus the population declines attributed to B. dendrobatidis. Understanding the mechanisms of mortality may also explain interspecific variation in susceptibility to chytridiomycosis. PMID:17972752

  1. Neuroendocrine control of spawning in amphibians and its practical applications.

    PubMed

    Vu, Maria; Trudeau, Vance L

    2016-08-01

    Across vertebrates, ovulation and sperm release are primarily triggered by the timed surge of luteinizing hormone (LH). These key reproductive events are governed by the action of several brain neuropeptides, pituitary hormones and gonadal steroids which operate to synchronize physiology with behaviour. In amphibians, it has long been recognized that the neuropeptide gonadotropin-releasing hormone (GnRH) has stimulatory effects to induce spawning. Extensive work in teleosts reveals an inhibitory role of dopamine in the GnRH-regulated release of LH. Preliminary evidence suggests that this may be a conserved function in amphibians. Emerging studies are proposing a growing list of modulators beyond GnRH that are involved in the control of spawning including prolactin, kisspeptins, pituitary adenylate cyclase-activating polypeptide, gonadotropin-inhibitory hormone and endocannabinoids. Based on these physiological data, spawning induction methods have been developed to test on selective amphibian species. However, several limitations remain to be investigated to strengthen the evidence for future applications. The current state of knowledge regarding the neuroendocrine control of spawning in amphibians will be reviewed in detail, the elements of which will have wide implications towards the captive breeding of endangered amphibian species for conservation. PMID:27013378

  2. The cause of global amphibian declines: a developmental endocrinologist's perspective

    PubMed Central

    Hayes, T. B.; Falso, P.; Gallipeau, S.; Stice, M.

    2010-01-01

    Greater than 70% of the world's amphibian species are in decline. We propose that there is probably not a single cause for global amphibian declines and present a three-tiered hierarchical approach that addresses interactions among and between ultimate and proximate factors that contribute to amphibian declines. There are two immediate (proximate) causes of amphibian declines: death and decreased recruitment (reproductive failure). Although much attention has focused on death, few studies have addressed factors that contribute to declines as a result of failed recruitment. Further, a great deal of attention has focused on the role of pathogens in inducing diseases that cause death, but we suggest that pathogen success is profoundly affected by four other ultimate factors: atmospheric change, environmental pollutants, habitat modification and invasive species. Environmental pollutants arise as likely important factors in amphibian declines because they have realized potential to affect recruitment. Further, many studies have documented immunosuppressive effects of pesticides, suggesting a role for environmental contaminants in increased pathogen virulence and disease rates. Increased attention to recruitment and ultimate factors that interact with pathogens is important in addressing this global crisis. PMID:20190117

  3. Annual Report: 2014: Partners in Amphibian and Reptile Conservation (PARC)

    USGS Publications Warehouse

    Weir, Linda A.; Nanjappa, P.; Apodaca, J. J.; Williams, J.

    2015-01-01

    Partners in Amphibian and Reptile Conservation (PARC) was established in 1999 to address the widespread declines, extinctions, and range reductions of amphibians and reptiles, with a focus on conservation of taxa and habitats in North America. Amphibians and reptiles are affected by a broad range of human activities, both as incidental effects of habitat alteration and direct effects from overexploitation; these animals are also burdened by humans attitudes – that amphibians and reptiles are either dangerous or of little environmental or economic value. However, PARC members understand these taxa are important parts of our natural and cultural heritage and they serve important roles in ecosystems throughout the world. With many amphibians and reptiles classified as threatened with extinction, conservation to ensure healthy populations of these animals has never been more important. As you will see herein, PARC’s 15th anniversary has been marked with major accomplishments and an ever-increasing momentum. With your help, PARC can continue to build on its successes and protect these vital species.

  4. Mitogenomic perspectives on the origin and phylogeny of living amphibians.

    PubMed

    Zhang, Peng; Zhou, Hui; Chen, Yue-Qin; Liu, Yi-Fei; Qu, Liang-Hu

    2005-06-01

    Establishing the relationships among modern amphibians (lissamphibians) and their ancient relatives is necessary for our understanding of early tetrapod evolution. However, the phylogeny is still intractable because of the highly specialized anatomy and poor fossil record of lissamphibians. Paleobiologists are still not sure whether lissamphibians are monophyletic or polyphyletic, and which ancient group (temnospondyls or lepospondyls) is most closely related to them. In an attempt to address these problems, eight mitochondrial genomes of living amphibians were determined and compared with previously published amphibian sequences. A comprehensive molecular phylogenetic analysis of nucleotide sequences yields a highly resolved tree congruent with the traditional hypotheses (Batrachia). By using a molecular clock-independent approach for inferring dating information from molecular phylogenies, we present here the first molecular timescale for lissamphibian evolution, which suggests that lissamphibians first emerged about 330 million years ago. By observing the fit between molecular and fossil times, we suggest that the temnospondyl-origin hypothesis for lissamphibians is more credible than other hypotheses. Moreover, under this timescale, the potential geographic origins of the main living amphibian groups are discussed: (i) advanced frogs (neobatrachians) may possess an Africa-India origin; (ii) salamanders may have originated in east Asia; (iii) the tropic forest of the Triassic Pangaea may be the place of origin for the ancient caecilians. An accurate phylogeny with divergence times can be also helpful to direct the search for "missing" fossils, and can benefit comparative studies of amphibian evolution. PMID:16012106

  5. [Muscle-skeletal pain].

    PubMed

    Vygonskaya, M V; Filatova, E G

    2016-01-01

    The paper is devoted to the most complicated aspects of low back pain. The differences between specific and nonspecific low back pain using the "red flags" system is highlighted. The authors consider the causes of pain chronification (the "yellow flags" system) and the necessity of using a biopsychosocial model. Main pathogenetic mechanisms of chronic muscle/skeletal pain are considered and the possible involvement of several mechanism in the pathogenesis of chronic pain as well as the use of complex therapy is discussed. The high efficacy and safety of ketorolac in treatment of nonspecific muscle/skeletal pain is demonstrated. PMID:27042717

  6. Hormonal regulation of ion and water transport in anuran amphibians.

    PubMed

    Uchiyama, Minoru; Konno, Norifumi

    2006-05-15

    Amphibians occupy a wide variety of ecological habitats, and their adaptation is made possible through the specialization of the epithelia of their osmoregulatory organs, such as the skin, kidney, and urinary bladder, which control the hydromineral and acid-base balance of their internal medium. Amphibians can change drastically plasma Na+, Cl-, and urea levels and excretion rates in response to environmental stimuli such as acute desiccation and changes in external salinity. Several hormones and the autonomic nervous system act to control osmoregulation. Several ion channels including an epithelial sodium channel (ENaC), a urea transporter (UT), and water channels (AQPs) are found in epithelial tissues of their osmoregulatory organs. This mini review examines the currents status of our knowledge about hormone receptors for arginine vasotocin, angiotensin II and aldosterone, and membrane ion channels and transporters, such as ENaC, UT, and AQPs in amphibians. PMID:16472810

  7. Pathogenesis of chytridiomycosis, a cause of catastrophic amphibian declines.

    PubMed

    Voyles, Jamie; Young, Sam; Berger, Lee; Campbell, Craig; Voyles, Wyatt F; Dinudom, Anuwat; Cook, David; Webb, Rebecca; Alford, Ross A; Skerratt, Lee F; Speare, Rick

    2009-10-23

    The pathogen Batrachochytrium dendrobatidis (Bd), which causes the skin disease chytridiomycosis, is one of the few highly virulent fungi in vertebrates and has been implicated in worldwide amphibian declines. However, the mechanism by which Bd causes death has not been determined. We show that Bd infection is associated with pathophysiological changes that lead to mortality in green tree frogs (Litoria caerulea). In diseased individuals, electrolyte transport across the epidermis was inhibited by >50%, plasma sodium and potassium concentrations were respectively reduced by approximately 20% and approximately 50%, and asystolic cardiac arrest resulted in death. Because the skin is critical in maintaining amphibian homeostasis, disruption to cutaneous function may be the mechanism by which Bd produces morbidity and mortality across a wide range of phylogenetically distant amphibian taxa. PMID:19900897

  8. The current status of amphibian and reptile ecotoxicological research

    USGS Publications Warehouse

    Sparling, D.W.; Bishop, C.A.; Linder, G.

    2000-01-01

    The extent of research conducted on the effects of contaminants on reptiles and amphibians has been scant compared to that of other vertebrate classes including fishes, birds and mammals. In a review of literature from 1972 until 1998 we found that only about 2.7% of the papers published on ecotoxicology in vertebrates concerned amphibians and 1.4% for reptiles. Most studies on amphibian ecotoxicology were on metals, pesticides, and acid deposition. For reptiles the greatest frequency of papers included metals, organochlorines, and others. In proportion to the taxonomic importance, far more papers were written on turtles than on other reptile orders. Most of the papers dealt with residues and very few dealt with effects of contaminant exposure.

  9. Amphibian research and monitoring initiative: Concepts and implementation

    USGS Publications Warehouse

    Corn, P.S.; Adams, M.J.; Battaglin, W.A.; Gallant, A.L.; James, D.L.; Knutson, M.; Langtimm, C.A.; Sauer, J.R.

    2005-01-01

    This report provides the basis for discussion and subsequent articulation of a national plan for the Amphibian Research and Monitoring Initiative (ARMI). The authors were members of a task force formed from within the U.S. Geological Survey (USGS) that included scientists with expertise in biology, cartography, hydrology, and statistics. The assignment of the task force was to extend work begun by the National Amphibian Leadership Group. This group, composed of senior USGS scientists, managers, and external authorities, met in Gainesville, Florida, in February 20001. The product of this meeting was a document outlining the framework for a national program to monitor amphibian populations and to conduct research into the causes of declines.

  10. Spatial network structure and amphibian persistence in stochastic environments

    PubMed Central

    Fortuna, Miguel A; Gómez-Rodríguez, Carola; Bascompte, Jordi

    2006-01-01

    In the past few years, the framework of complex networks has provided new insight into the organization and function of biological systems. However, in spite of its potential, spatial ecology has not yet fully incorporated tools and concepts from network theory. In the present study, we identify a large spatial network of temporary ponds, which are used as breeding sites by several amphibian species. We investigate how the structural properties of the spatial network change as a function of the amphibian dispersal distance and the hydric conditions. Our measures of network topology suggest that the observed spatial structure of ponds is robust to drought (compared with similar random structures), allowing the movement of amphibians to and between flooded ponds, and hence, increasing the probability of reproduction even in dry seasons. PMID:16777733

  11. Granular gland transcriptomes in stimulated amphibian skin secretions.

    PubMed Central

    Chen, Tianbao; Farragher, Susan; Bjourson, Anthony J; Orr, David F; Rao, Pingfan; Shaw, Chris

    2003-01-01

    Amphibian defensive skin secretions are complex, species-specific cocktails of biologically active molecules, including many uncharacterized peptides. The study of such secretions for novel peptide discovery is time-limited, as amphibians are in rapid global decline. While secretion proteome analysis is non-lethal, transcriptome analysis has until now required killing of specimens prior to skin dissection for cDNA library construction. Here we present the discovery that polyadenylated mRNAs encoding dermal granular gland peptides are present in defensive skin secretions, stabilized by endogenous nucleic acid-binding amphipathic peptides. Thus parallel secretory proteome and transcriptome analyses can be performed without killing the specimen in this model amphibian system--a finding that has important implications in conservation of biodiversity within this threatened vertebrate taxon and whose mechanistics may have broader implications in biomolecular science. PMID:12413397

  12. 50 CFR 16.14 - Importation of live amphibians or their eggs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 1 2013-10-01 2013-10-01 false Importation of live amphibians or their... Importation of live amphibians or their eggs. Upon the filing of a written declaration with the District Director of Customs at the port of entry as required under § 14.61, all species of live amphibians or...

  13. 50 CFR 16.14 - Importation of live amphibians or their eggs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 1 2014-10-01 2014-10-01 false Importation of live amphibians or their... Importation of live amphibians or their eggs. Upon the filing of a written declaration with the District Director of Customs at the port of entry as required under § 14.61, all species of live amphibians or...

  14. 50 CFR 16.14 - Importation of live amphibians or their eggs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 1 2012-10-01 2012-10-01 false Importation of live amphibians or their... Importation of live amphibians or their eggs. Upon the filing of a written declaration with the District Director of Customs at the port of entry as required under § 14.61, all species of live amphibians or...

  15. 50 CFR 16.14 - Importation of live amphibians or their eggs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 1 2011-10-01 2011-10-01 false Importation of live amphibians or their... Importation of live amphibians or their eggs. Upon the filing of a written declaration with the District Director of Customs at the port of entry as required under § 14.61, all species of live amphibians or...

  16. 50 CFR 16.14 - Importation of live amphibians or their eggs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Importation of live amphibians or their... Importation of live amphibians or their eggs. Upon the filing of a written declaration with the District Director of Customs at the port of entry as required under § 14.61, all species of live amphibians or...

  17. The Amphibian Diversity of Bukit Jana, Taiping, Perak

    PubMed Central

    Shahrudin, Shahriza; Jaafar, Ibrahim

    2012-01-01

    The study on the amphibian fauna of Bukit Jana, Taiping, Perak was carried out from January 2009 until December 2010 with a total of 12 nights of observation. Twenty four species of frogs from 14 genera and 6 families were recorded to inhabit the Bukit Jana areas. Seven commensal species were found around human habitations near the foothill whereas the others are typical forest frogs found mostly near the rivers, streams and forest floor. This is the first amphibian checklist of Bukit Jana, Perak and it contributed 22% out of 107 species of frogs that are recorded to inhabit Peninsular Malaysia. PMID:24575233

  18. Effects of freshwater petroleum contamination on amphibian hatching and metamorphosis

    SciTech Connect

    Mahaney, P.A. . Dept. of Zoology)

    1994-02-01

    This study examined the effects of freshwater petroleum contamination on amphibian reproduction. The primary objectives were to assess the potential environmental and physiological impacts of runoff petroleum products on amphibians, using the green tree frog (Hyla cinerea) as a target species and engine crankcase oil as a contaminant. Egg hatching success, tadpole growth, and successful metamorphosis were measured in four concentrations of oil. The effects of oil on food source was also studied. Hatching success was not measurably influenced by the presence of oil. Tadpole and alga growth were negatively associated with the presence of oil. No tadpoles from the high concentration of oil treatments successfully metamorphosed.

  19. Ticks infesting amphibians and reptiles in Pernambuco, Northeastern Brazil.

    PubMed

    Dantas-Torres, Filipe; Oliveira-Filho, Edmilson F; Soares, Fábio Angelo M; Souza, Bruno O F; Valença, Raul Baltazar P; Sá, Fabrício B

    2008-01-01

    Ticks infesting amphibians and reptiles in the State of Pernambuco are reviewed, based on the current literature and new collections recently carried out by the authors. To date, three tick species have been found on amphibians and reptiles in Pernambuco. Amblyomma fuscum appears to be exclusively associated with Boa constrictor, its type host. Amblyomma rotundatum has a relatively low host-specificity, being found on toads, snakes, and iguana. Amblyomma dissimile has been found on a lizard and also small mammals (i.e., rodents and marsupials). New tick-host associations and locality records are given. PMID:19265581

  20. Structure of Skeletal Muscle

    MedlinePlus

    ... Cells, Tissues, & Membranes Cell Structure & Function Cell Structure Cell Function Body Tissues Epithelial Tissue Connective Tissue Muscle Tissue ... nerves. This is directly related to the primary function of skeletal muscle, ... an impulse from a nerve cell. Generally, an artery and at least one vein ...

  1. Lipid diffusibility in the intact erythrocyte membrane.

    PubMed Central

    Bloom, J A; Webb, W W

    1983-01-01

    The lateral diffusion of fluorescent lipid analogues in the plasma membrane of intact erythrocytes from man, mouse, rabbit, and frog has been measured by fluorescence photobleaching recovery (FPR). Intact cells from dystrophic, normoblastic, hemolytic, and spherocytotic mouse mutants; from hypercholesterolemic rabbits and humans; and from prenatal, neonatal, and juvenile mice have been compared with corresponding normals. The lateral diffusion coefficient (D) for 3,3'-dioctadecylindodicarbocyanine iodide (DiI[5]) in intact normal human erythrocytes is D = 8.2 +/- 1.2 X 10(-9) cm2/s at 25 degrees C and D = 2.1 +/- 0.4 X 10(-8) cm2/s at 37 degrees C, and varies approximately 50-fold between 1 degree and 42 degrees C. The diffusion constants of lipid analogue rhodamine-B phosphatidylethanolamine (RBPE) are about twice those of DiI[5]. The temperature dependence and magnitude of D vary by up to a factor of 3 between species and are only influenced by donor age in prenatals. DiI[5] diffusibility is not perturbed by the presence of calcium or local anesthetics or by spectrin depletion (via mutation). However, lipid-analogue diffusibility in erythrocyte ghosts may differ from intact cells. Dietary hypercholesterolemia in rabbits reduces the diffusion coefficient and eliminates the characteristic break in Arrhenius plots of D found in all other cells studied except frog. PMID:6603237

  2. HYDROCARBON VAPOR DIFFUSION IN INTACT CORE SLEEVES

    EPA Science Inventory

    The diffusion of 2,2,4-trimethylpentane (TMP) and 2,2,5-trimethylhexane (TMH) vapors out of residually contaminated sandy soil from the U.S. Environmental Protection Agency (EPA) field research site at Traverse City, Michigan, was measured and modeled. he headspace of an intact c...

  3. HYDROCARBON VAPOR DIFFUSION IN INTACT CORE SLEEVES

    EPA Science Inventory

    The diffusion of 2,2,4-trimethylpentane (TMP) and 2,2,5-trimethylhexane (TMH) vapors put of residually contaminated sandy soil from the U.S. Environmental Protection Agency (EPA) field research site at Traverse City, Michigan, was measured and modeled. The headspace of an intact ...

  4. Gravity and Skeletal Growth

    NASA Technical Reports Server (NTRS)

    Morey-Holton, Emily; Turner, Russell T.

    1999-01-01

    Two simultaneous experiments were performed using 5-week-old male Sprague Dawley rats; in one study, the rats were flown in low earth orbit; in the other study, the hindlimbs of the growing rats were elevated to prevent weight bearing. Following 9 d of unloading, weight bearing was restored for 4, 28, and 76 hrs. Afterwards, additional hindlimb unloading experiments were performed to evaluate the skeletal response to 0, 2, 4, 6, 8, 10, 12, 16, and 24 hrs of restored weight bearing following 7 d of unloading. Cancellous and cortical bone histomorphometry were evaluated in the left tibia at the proximal metaphysis and in the left femur at mid-diaphysis, respectively. Steady-state mRNA levels for bone matrix proteins and skeletal signaling peptides were determined in total cellular RNA extracted from trabeculae from the right proximal tibiametaphysis and periosteum from the right femur. Spaceflight and hindlimb unloading each resulted in cancellous osteopenia, as well as a tendency towards decreased periosteal bone formation. Both models for skeletal unloading resulted in site specific reductions in mRNA levels for transforming growth factor-beta (sub 1) (TGF-beta) osteocalcin (OC), and prepro-alpha (I) subunit of type 1 collagen (collagen) and little or no changes in mRNA levels for glyceraldehyde-3-phosphate dehydrogenase (GAP) and insulin-like growth factor I (IGF-I). Restoration of normal weight bearing resulted in transient increases in mRNA levels for the bone matrix proteins and TGF-beta in the proximal metaphysis and periosteum and no changes in either GAP or IGF-I mRNA levels. The timecourse for the response differed between the two skeletal compartments; the tibial metaphysis responded much more quickly to reloading. These results suggest that the skeletal adaptation to acute physiological changes in mechanical usage are mediated, in part, by changes in mRNA levels for bone matrix proteins and TGF-beta.

  5. Small Particles Intact Capture Experiment (SPICE)

    NASA Astrophysics Data System (ADS)

    Nishioka, Ken-Ji; Carle, G. C.; Bunch, T. E.; Mendez, David J.; Ryder, J. T.

    The Small Particles Intact Capture Experiment (SPICE) will develop technologies and engineering techniques necessary to capture nearly intact, uncontaminated cosmic and interplanetary dust particles (IDP's). Successful capture of such particles will benefit the exobiology and planetary science communities by providing particulate samples that may have survived unaltered since the formation of the solar system. Characterization of these particles may contribute fundamental data to our knowledge of how these particles could have formed into our planet Earth and, perhaps, contributed to the beginnings of life. The term 'uncontaminated' means that captured cosmic and IDP particles are free of organic contamination from the capture process and the term 'nearly intact capture' means that their chemical and elemental components are not materially altered during capture. The key to capturing cosmic and IDP particles that are organic-contamination free and nearly intact is the capture medium. Initial screening of capture media included organic foams, multiple thin foil layers, and aerogel (a silica gel); but, with the exception of aerogel, the requirements of no contamination or nearly intact capture were not met. To ensure no contamination of particles in the capture process, high-purity aerogel was chosen. High-purity aerogel results in high clarity (visual clearness), a useful quality in detection and recovery of embedded captured particles from the aerogel. P. Tsou at the Jet Propulsion Laboratory (JPL) originally described the use of aerogel for this purpose and reported laboratory test results. He has flown aerogel as a 'GAS-can Lid' payload on STS-47 and is evaluating the results. The Timeband Capture Cell Experiment (TICCE), a Eureca 1 experiment, is also flying aerogel and is scheduled for recovery in late April.

  6. Small Particles Intact Capture Experiment (SPICE)

    NASA Technical Reports Server (NTRS)

    Nishioka, Ken-Ji; Carle, G. C.; Bunch, T. E.; Mendez, David J.; Ryder, J. T.

    1994-01-01

    The Small Particles Intact Capture Experiment (SPICE) will develop technologies and engineering techniques necessary to capture nearly intact, uncontaminated cosmic and interplanetary dust particles (IDP's). Successful capture of such particles will benefit the exobiology and planetary science communities by providing particulate samples that may have survived unaltered since the formation of the solar system. Characterization of these particles may contribute fundamental data to our knowledge of how these particles could have formed into our planet Earth and, perhaps, contributed to the beginnings of life. The term 'uncontaminated' means that captured cosmic and IDP particles are free of organic contamination from the capture process and the term 'nearly intact capture' means that their chemical and elemental components are not materially altered during capture. The key to capturing cosmic and IDP particles that are organic-contamination free and nearly intact is the capture medium. Initial screening of capture media included organic foams, multiple thin foil layers, and aerogel (a silica gel); but, with the exception of aerogel, the requirements of no contamination or nearly intact capture were not met. To ensure no contamination of particles in the capture process, high-purity aerogel was chosen. High-purity aerogel results in high clarity (visual clearness), a useful quality in detection and recovery of embedded captured particles from the aerogel. P. Tsou at the Jet Propulsion Laboratory (JPL) originally described the use of aerogel for this purpose and reported laboratory test results. He has flown aerogel as a 'GAS-can Lid' payload on STS-47 and is evaluating the results. The Timeband Capture Cell Experiment (TICCE), a Eureca 1 experiment, is also flying aerogel and is scheduled for recovery in late April.

  7. Red List of amphibians and reptiles of the Wadden Sea area

    NASA Astrophysics Data System (ADS)

    Fog, K.; Podloucky, R.; Dierking, U.; Stumpel, A. H. P.

    1996-10-01

    In the Wadden Sea, in total, 8 species of amphibians and 4 species of reptiles are threatened in at least one subregion. Of these, 7 species of amphibians and all 4 species of reptiles are threatened in the entire area and are therefore placed on the trilateral Red List. 1 species of the listed reptiles is (probably) extinct in the entire Wadden Sea area. The status of 1 species of amphibians is endangered, the status of (probably) 4 species of amphibians and 3 species of reptiles are vulnerable and of 2 species of amphibians susceptible.

  8. Slow dynamics of the amphibian tympanic membrane

    NASA Astrophysics Data System (ADS)

    Bergevin, Christopher; Meenderink, Sebastiaan W. F.; van der Heijden, Marcel; Narins, Peter M.

    2015-12-01

    Several studies have demonstrated that delays associated with evoked otoacoustic emissions (OAEs) largely originate from filter delays of resonant elements in the inner ear. However, one vertebrate group is an exception: Anuran (frogs and toads) amphibian OAEs exhibit relatively long delays (several milliseconds), yet relatively broad tuning. These delays, also apparent in auditory nerve fiber (ANF) responses, have been partially attributed to the middle ear (ME), with a total forward delay of ˜0.7 ms (˜30 times longer than in gerbil). However, ME forward delays only partially account for the longer delays of OAEs and ANF responses. We used scanning laser Doppler vibrometery to map surface velocity over the tympanic membrane (TyM) of anesthetized bullfrogs (Rana catesbeiana). Our main finding is a circularly-symmetric wave on the TyM surface, starting at the outer edges of the TyM and propagating inward towards the center (the site of the ossicular attachment). This wave exists for frequencies ˜0.75-3 kHz, overlapping the range of bullfrog hearing (˜0.05-1.7 kHz). Group delays associated with this wave varied from 0.4 to 1.2 ms and correlated with with TyM diameter, which ranged from ˜6-16 mm. These delays correspond well to those from previous ME measurements. Presumably the TyM waves stem from biomechanical constraints of semi-aquatic species with a relatively large tympanum. We investigated some of these constraints by measuring the pressure ratio across the TyM (˜10-30 dB drop, delay of ˜0.35 ms), the effects of ossicular interruption, the changes due to physiological state of TyM (`dry-out'), and by calculating the middle-ear input impedance. In summary, we found a slow, inward-traveling wave on the TyM surface that accounts for a substantial fraction of the relatively long otoacoustic and neurophysiological delays previously observed in the anuran inner ear.

  9. Cranial muscles in amphibians: development, novelties and the role of cranial neural crest cells

    PubMed Central

    Schmidt, Jennifer; Piekarski, Nadine; Olsson, Lennart

    2013-01-01

    Our research on the evolution of the vertebrate head focuses on understanding the developmental origins of morphological novelties. Using a broad comparative approach in amphibians, and comparisons with the well-studied quail-chicken system, we investigate how evolutionarily conserved or variable different aspects of head development are. Here we review research on the often overlooked development of cranial muscles, and on its dependence on cranial cartilage development. In general, cranial muscle cell migration and the spatiotemporal pattern of cranial muscle formation appears to be very conserved among the few species of vertebrates that have been studied. However, fate-mapping of somites in the Mexican axolotl revealed differences in the specific formation of hypobranchial muscles (tongue muscles) in comparison to the chicken. The proper development of cranial muscles has been shown to be strongly dependent on the mostly neural crest-derived cartilage elements in the larval head of amphibians. For example, a morpholino-based knock-down of the transcription factor FoxN3 in Xenopus laevis has drastic indirect effects on cranial muscle patterning, although the direct function of the gene is mostly connected to neural crest development. Furthermore, extirpation of single migratory streams of cranial neural crest cells in combination with fate-mapping in a frog shows that individual cranial muscles and their neural crest-derived connective tissue attachments originate from the same visceral arch, even when the muscles attach to skeletal components that are derived from a different arch. The same pattern has also been found in the chicken embryo, the only other species that has been thoroughly investigated, and thus might be a conserved pattern in vertebrates that reflects the fundamental nature of a mechanism that keeps the segmental order of the head in place despite drastic changes in adult anatomy. There is a need for detailed comparative fate-mapping of pre

  10. Examining the Evidence for Chytridiomycosis in Threatened Amphibian Species

    PubMed Central

    Heard, Matthew; Smith, Katherine F.; Ripp, Kelsey

    2011-01-01

    Extinction risks are increasing for amphibians due to rising threats and minimal conservation efforts. Nearly one quarter of all threatened/extinct amphibians in the IUCN Red List is purportedly at risk from the disease chytridiomycosis. However, a closer look at the data reveals that Batrachochytrium dendrobatidis (the causal agent) has been identified and confirmed to cause clinical disease in only 14% of these species. Primary literature surveys confirm these findings; ruling out major discrepancies between Red List assessments and real-time science. Despite widespread interest in chytridiomycosis, little progress has been made between assessment years to acquire evidence for the role of chytridiomycosis in species-specific amphibian declines. Instead, assessment teams invoke the precautionary principle when listing chytridiomycosis as a threat. Precaution is valuable when dealing with the world's most threatened taxa, however scientific research is needed to distinguish between real and predicted threats in order to better prioritize conservation efforts. Fast paced, cost effective, in situ research to confirm or rule out chytridiomycosis in species currently hypothesized to be threatened by the disease would be a step in the right direction. Ultimately, determining the manner in which amphibian conservation resources are utilized is a conversation for the greater conservation community that we hope to stimulate here. PMID:21826233

  11. Expanding Distribution of Lethal Amphibian Fungus Batrachochytrium salamandrivorans in Europe.

    PubMed

    Spitzen-van der Sluijs, Annemarieke; Martel, An; Asselberghs, Johan; Bales, Emma K; Beukema, Wouter; Bletz, Molly C; Dalbeck, Lutz; Goverse, Edo; Kerres, Alexander; Kinet, Thierry; Kirst, Kai; Laudelout, Arnaud; Marin da Fonte, Luis F; Nöllert, Andreas; Ohlhoff, Dagmar; Sabino-Pinto, Joana; Schmidt, Benedikt R; Speybroeck, Jeroen; Spikmans, Frank; Steinfartz, Sebastian; Veith, Michael; Vences, Miguel; Wagner, Norman; Pasmans, Frank; Lötters, Stefan

    2016-07-01

    Emerging fungal diseases can drive amphibian species to local extinction. During 2010-2016, we examined 1,921 urodeles in 3 European countries. Presence of the chytrid fungus Batrachochytrium salamandrivorans at new locations and in urodeles of different species expands the known geographic and host range of the fungus and underpins its imminent threat to biodiversity. PMID:27070102

  12. Can Myxosporean parasites compromise fish and amphibian reproduction?

    PubMed Central

    Sitjà-Bobadilla, Ariadna

    2009-01-01

    Research into fish and amphibian reproduction has increased exponentially in recent years owing to the expansion of the aquaculture industry, the need to recover fishery populations, the impact of endocrine disruptors on the aquatic environment and the global decline of amphibian populations. This review focuses on a group of parasites, the Myxozoa, that affect fish and amphibian reproduction. Lists of the myxosporeans that specifically infect gonads are provided. Most of these are parasitic of freshwater hosts, and most amphibian cases are reported from testes. Sex specificity and sex reversal are discussed in relation to gonadal parasitism. The immune response of the fish to the infection is described, and the contribution of the immunoprivilege of gonads to host invasion is emphasized. The pathological effect of these parasites can be significant, especially in aquacultured broodstocks, on some occasions, leading to parasitic castration. Although myxosporean parasites are currently not very frequent in gonads, their impact could increase in the future owing to the transactions in the global market. Their easy release into the aquatic environment with spawning could make their spreading even more feasible. In the absence of commercial drugs or vaccines to treat and prevent these infections, there is an urgent need to develop specific, rapid and reliable diagnostic tools to control and manage animal movements. In addition, much effort is still to be made on deciphering the life cycle of these organisms, their invasion strategies and their immune evasion mechanisms. PMID:19474043

  13. FACTORS ADVERSELY AFFECTING AMPHIBIAN POPULATIONS IN THE US

    EPA Science Inventory

    Factors known or suspected to be adversely affecting native amphibian populations in the US were identified using information from species accounts written in a standardized format by multiple authors in a forthcoming book. Specific adverse factors were identified for 53 (58%) of...

  14. Can myxosporean parasites compromise fish and amphibian reproduction?

    PubMed

    Sitjà-Bobadilla, Ariadna

    2009-08-22

    Research into fish and amphibian reproduction has increased exponentially in recent years owing to the expansion of the aquaculture industry, the need to recover fishery populations, the impact of endocrine disruptors on the aquatic environment and the global decline of amphibian populations. This review focuses on a group of parasites, the Myxozoa, that affect fish and amphibian reproduction. Lists of the myxosporeans that specifically infect gonads are provided. Most of these are parasitic of freshwater hosts, and most amphibian cases are reported from testes. Sex specificity and sex reversal are discussed in relation to gonadal parasitism. The immune response of the fish to the infection is described, and the contribution of the immunoprivilege of gonads to host invasion is emphasized. The pathological effect of these parasites can be significant, especially in aquacultured broodstocks, on some occasions, leading to parasitic castration. Although myxosporean parasites are currently not very frequent in gonads, their impact could increase in the future owing to the transactions in the global market. Their easy release into the aquatic environment with spawning could make their spreading even more feasible. In the absence of commercial drugs or vaccines to treat and prevent these infections, there is an urgent need to develop specific, rapid and reliable diagnostic tools to control and manage animal movements. In addition, much effort is still to be made on deciphering the life cycle of these organisms, their invasion strategies and their immune evasion mechanisms. PMID:19474043

  15. Using Reptile and Amphibian Activities in the Classroom

    ERIC Educational Resources Information Center

    Tomasek, Terry; Matthews, Catherine E.

    2008-01-01

    Reptiles and amphibians are a diverse and interesting group of organisms. The four activities described in this article take students' curiosity into the realm of scientific understanding. The activities involve the concepts of species identification; animal adaptations, communication, and habitat; and conservation. (Contains 1 table and 2…

  16. RISK ASSESSMENT FOR THE EFFECTS OF SOLAR RADIATION ON AMPHIBIANS

    EPA Science Inventory

    Recent studies have demonstrated that exposure to solar ultraviolet radiation (UVR) can cause mortality and increase the occurrence of eye and limb malformation in some species of amphibians. Based on these reports and various field observations, it has been hypothesized that UV...

  17. On the worrying fate of Data Deficient amphibians.

    PubMed

    Nori, Javier; Loyola, Rafael

    2015-01-01

    The 'Data Deficient' (DD) category of the IUCN Red List assembles species that cannot be placed in another category due to insufficient information. This process generates uncertainty about whether these species are safe or actually in danger. Here, we give a global overview on the current situation of DD amphibian species (almost a quarter of living amphibians) considering land-use change through habitat modification, the degree of protection of each species and the socio-political context of each country harboring DD species. We found that DD amphibians have, on average, 81% of their ranges totally outside protected areas. Worryingly, more than half of DD species have less than 1% of their distribution represented in protected areas. Furthermore, the percentage of overlap between species' range and human-modified landscapes is high, at approximately 58%. Many countries harboring a large number of DD species show a worrying socio-political trend illustrated by substantial, recent incremental increases in the Human Development Index and lower incremental increases in the establishment of protected areas. Most of these are African countries, which are located mainly in the central and southern regions of the continent. Other countries with similar socio-political trends are in southeastern Asia, Central America, and in the northern region of South America. This situation is concerning, but it also creates a huge opportunity for considering DD amphibians in future conservation assessments, planning, and policy at different levels of government administration. PMID:25965422

  18. AMPHIBIAN DECLINE, ULTRAVIOLET RADIATION AND LOCAL POPULATION ADAPTATION

    EPA Science Inventory

    Amphibian population declines have been noted on both local and global scales. Causes for these declines are unknown although many hypotheses have been offered. In areas adjacent to human development, loss of habitat is a fairly well accepted cause. However in isolated, seemingl...

  19. Preliminary checklist of amphibians and reptiles from Baramita, Guyana

    USGS Publications Warehouse

    Reynolds, R.P.; MacCulloch, R.D.

    2012-01-01

    We provide an initial checklist of the herpetofauna of Baramita, a lowland rainforest site in the Northwest Region of Guyana. Twenty-five amphibian and 28 reptile species were collected during two separate dry-season visits. New country records for two species of snakes are documented, contributing to the knowledge on the incompletely known herpetofauna of Guyana.

  20. On the Worrying Fate of Data Deficient Amphibians

    PubMed Central

    Nori, Javier; Loyola, Rafael

    2015-01-01

    The ‘Data Deficient’ (DD) category of the IUCN Red List assembles species that cannot be placed in another category due to insufficient information. This process generates uncertainty about whether these species are safe or actually in danger. Here, we give a global overview on the current situation of DD amphibian species (almost a quarter of living amphibians) considering land-use change through habitat modification, the degree of protection of each species and the socio-political context of each country harboring DD species. We found that DD amphibians have, on average, 81% of their ranges totally outside protected areas. Worryingly, more than half of DD species have less than 1% of their distribution represented in protected areas. Furthermore, the percentage of overlap between species’ range and human-modified landscapes is high, at approximately 58%. Many countries harboring a large number of DD species show a worrying socio-political trend illustrated by substantial, recent incremental increases in the Human Development Index and lower incremental increases in the establishment of protected areas. Most of these are African countries, which are located mainly in the central and southern regions of the continent. Other countries with similar socio-political trends are in southeastern Asia, Central America, and in the northern region of South America. This situation is concerning, but it also creates a huge opportunity for considering DD amphibians in future conservation assessments, planning, and policy at different levels of government administration. PMID:25965422

  1. Measuring the Meltdown: Drivers of Global Amphibian Extinction and Decline

    PubMed Central

    Sodhi, Navjot S.; Bickford, David; Diesmos, Arvin C.; Lee, Tien Ming; Koh, Lian Pin; Brook, Barry W.; Sekercioglu, Cagan H.; Bradshaw, Corey J. A.

    2008-01-01

    Habitat loss, climate change, over-exploitation, disease and other factors have been hypothesised in the global decline of amphibian biodiversity. However, the relative importance of and synergies among different drivers are still poorly understood. We present the largest global analysis of roughly 45% of known amphibians (2,583 species) to quantify the influences of life history, climate, human density and habitat loss on declines and extinction risk. Multi-model Bayesian inference reveals that large amphibian species with small geographic range and pronounced seasonality in temperature and precipitation are most likely to be Red-Listed by IUCN. Elevated habitat loss and human densities are also correlated with high threat risk. Range size, habitat loss and more extreme seasonality in precipitation contributed to decline risk in the 2,454 species that declined between 1980 and 2004, compared to species that were stable (n = 1,545) or had increased (n = 28). These empirical results show that amphibian species with restricted ranges should be urgently targeted for conservation. PMID:18286193

  2. Emerging contaminants and their potential effects on amphibians and reptiles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Serious threats to the health and sustainability of global amphibian populations have been well documented over the last few decades. Encroachment upon and destruction of primary habitat is the most critical threat, but some species have disappeared while their habitat remains. Additional stressor...

  3. Effects of pollution on freshwater fish and amphibians

    SciTech Connect

    Pickering, Q.H.; Hunt, E.P.; Phipps, G.L.; Roush, T.H.; Smith, W.E.; Spehar, D.L.; Stephan, C.E.; Tanner, D.K.

    1983-06-01

    A literature review is presented dealing with studies on the effects of pollution on freshwater fish and amphibians. The pollutants studied included acid mine drainage, PCBs, cadmium, lead, naphthalene, plutonium, in addition to several studies dealing with pH effects. (JMT)

  4. Pesticides in amphibian habitats of central and northern California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amphibians in California are facing serious population declines. Contaminants, especially pesticides, have been linked to these declines. This study reports on a survey of central and northern California wetlands sampled along four transects associated with Lassen National Park, Lake Tahoe, Yosemit...

  5. Utricular otoconia of some amphibians have calcitic morphology

    NASA Technical Reports Server (NTRS)

    Pote, K. G.; Ross, M. D.

    1993-01-01

    This report concerns the morphological features of otoconia removed from the inner ear of four amphibian species. Results from scanning electron microscopic examination are compared based on the site of origin. These results show that utricular otoconia have a mineral structure that mimics calcite, rather than the widely accepted idea that they are mineralized by calcium carbonate of the aragonite polymorph.

  6. Batrachochytrium salamandrivorans sp. nov. causes lethal chytridiomycosis in amphibians

    PubMed Central

    Martel, An; Spitzen-van der Sluijs, Annemarieke; Blooi, Mark; Bert, Wim; Ducatelle, Richard; Fisher, Matthew C.; Woeltjes, Antonius; Bosman, Wilbert; Chiers, Koen; Bossuyt, Franky; Pasmans, Frank

    2013-01-01

    The current biodiversity crisis encompasses a sixth mass extinction event affecting the entire class of amphibians. The infectious disease chytridiomycosis is considered one of the major drivers of global amphibian population decline and extinction and is thought to be caused by a single species of aquatic fungus, Batrachochytrium dendrobatidis. However, several amphibian population declines remain unexplained, among them a steep decrease in fire salamander populations (Salamandra salamandra) that has brought this species to the edge of local extinction. Here we isolated and characterized a unique chytrid fungus, Batrachochytrium salamandrivorans sp. nov., from this salamander population. This chytrid causes erosive skin disease and rapid mortality in experimentally infected fire salamanders and was present in skin lesions of salamanders found dead during the decline event. Together with the closely related B. dendrobatidis, this taxon forms a well-supported chytridiomycete clade, adapted to vertebrate hosts and highly pathogenic to amphibians. However, the lower thermal growth preference of B. salamandrivorans, compared with B. dendrobatidis, and resistance of midwife toads (Alytes obstetricans) to experimental infection with B. salamandrivorans suggest differential niche occupation of the two chytrid fungi. PMID:24003137

  7. Effects of Terrestrial Buffer Zones on Amphibians on Golf Courses

    PubMed Central

    Puglis, Holly J.; Boone, Michelle D.

    2012-01-01

    A major cause of amphibian declines worldwide is habitat destruction or alteration. Public green spaces, such as golf courses and parks, could serve as safe havens to curb the effects of habitat loss if managed in ways to bolster local amphibian communities. We reared larval Blanchard's cricket frogs (Acris blanchardi) and green frogs (Rana clamitans) in golf course ponds with and without 1 m terrestrial buffer zones, and released marked cricket frog metamorphs at the golf course ponds they were reared in. Larval survival of both species was affected by the presence of a buffer zone, with increased survival for cricket frogs and decreased survival for green frogs when reared in ponds with buffer zones. No marked cricket frog juveniles were recovered at any golf course pond in the following year, suggesting that most animals died or migrated. In a separate study, we released cricket frogs in a terrestrial pen and allowed them to choose between mown and unmown grass. Cricket frogs had a greater probability of using unmown versus mown grass. Our results suggest that incorporating buffer zones around ponds can offer suitable habitat for some amphibian species and can improve the quality of the aquatic environment for some sensitive local amphibians. PMID:22761833

  8. Expanding Distribution of Lethal Amphibian Fungus Batrachochytrium salamandrivorans in Europe

    PubMed Central

    Spitzen-van der Sluijs, Annemarieke; Martel, An; Asselberghs, Johan; Bales, Emma K.; Beukema, Wouter; Bletz, Molly C.; Dalbeck, Lutz; Goverse, Edo; Kerres, Alexander; Kinet, Thierry; Kirst, Kai; Laudelout, Arnaud; Marin da Fonte, Luis F.; Nöllert, Andreas; Ohlhoff, Dagmar; Sabino-Pinto, Joana; Schmidt, Benedikt R.; Speybroeck, Jeroen; Spikmans, Frank; Steinfartz, Sebastian; Veith, Michael; Vences, Miguel; Wagner, Norman; Pasmans, Frank

    2016-01-01

    Emerging fungal diseases can drive amphibian species to local extinction. During 2010–2016, we examined 1,921 urodeles in 3 European countries. Presence of the chytrid fungus Batrachochytrium salamandrivorans at new locations and in urodeles of different species expands the known geographic and host range of the fungus and underpins its imminent threat to biodiversity. PMID:27070102

  9. UPDATE ON COORDINATED STUDIES OF AMPHIBIAN DISTRIBUTIONS AND UV RADIATION

    EPA Science Inventory

    In February of 2000 researchers from the EPA, the National Park Service, other governmental agencies, and academia formulated a plan for coordinated studies of amphibian distributions and aquatic ultraviolet radiation exposure risks in several national parks. At this point we hav...

  10. Using Amphibians and Reptiles To Learn the Process of Science.

    ERIC Educational Resources Information Center

    Greene, Janice Schnake; Greene, Brian D.

    2001-01-01

    Discusses using amphibians and reptiles as an excellent resource for students to observe and gain an understanding of the process of science. These animals are easy to maintain in the classroom and play important roles in ecosystems as the prey for many birds and mammals and as the predators of various organisms. (SAH)

  11. Spatial Biodiversity Patterns of Madagascar's Amphibians and Reptiles

    PubMed Central

    Brown, Jason L.; Sillero, Neftali; Glaw, Frank; Bora, Parfait; Vieites, David R.; Vences, Miguel

    2016-01-01

    Madagascar has become a model region for testing hypotheses of species diversification and biogeography, and many studies have focused on its diverse and highly endemic herpetofauna. Here we combine species distribution models of a near-complete set of species of reptiles and amphibians known from the island with body size data and a tabulation of herpetofaunal communities from field surveys, compiled up to 2008. Though taxonomic revisions and novel distributional records arose since compilation, we are confident that the data are appropriate for inferring and comparing biogeographic patterns among these groups of organisms. We observed species richness of both amphibians and reptiles was highest in the humid rainforest biome of eastern Madagascar, but reptiles also show areas of high richness in the dry and subarid western biomes. In several amphibian subclades, especially within the Mantellidae, species richness peaks in the central eastern geographic regions while in reptiles different subclades differ distinctly in their richness centers. A high proportion of clades and subclades of both amphibians and reptiles have a peak of local endemism in the topographically and bioclimatically diverse northern geographic regions. This northern area is roughly delimited by a diagonal spanning from 15.5°S on the east coast to ca. 15.0°S on the west coast. Amphibian diversity is highest at altitudes between 800–1200 m above sea-level whereas reptiles have their highest richness at low elevations, probably reflecting the comparatively large number of species specialized to the extended low-elevation areas in the dry and subarid biomes. We found that the range sizes of both amphibians and reptiles strongly correlated with body size, and differences between the two groups are explained by the larger body sizes of reptiles. However, snakes have larger range sizes than lizards which cannot be readily explained by their larger body sizes alone. Range filling, i.e., the amount

  12. Xenopus egg cytoplasm with intact actin.

    PubMed

    Field, Christine M; Nguyen, Phuong A; Ishihara, Keisuke; Groen, Aaron C; Mitchison, Timothy J

    2014-01-01

    We report optimized methods for preparing Xenopus egg extracts without cytochalasin D, that we term "actin-intact egg extract." These are undiluted egg cytoplasm that contains abundant organelles, and glycogen which supplies energy, and represents the least perturbed cell-free cytoplasm preparation we know of. We used this system to probe cell cycle regulation of actin and myosin-II dynamics (Field et al., 2011), and to reconstitute the large, interphase asters that organize early Xenopus embryos (Mitchison et al., 2012; Wühr, Tan, Parker, Detrich, & Mitchison, 2010). Actin-intact Xenopus egg extracts are useful for analysis of actin dynamics, and interaction of actin with other cytoplasmic systems, in a cell-free system that closely mimics egg physiology, and more generally for probing the biochemistry and biophysics of the egg, zygote, and early embryo. Detailed protocols are provided along with assays used to check cell cycle state and tips for handling and storing undiluted egg extracts. PMID:24630119

  13. Inventory of amphibians and reptiles at Death Valley National Park

    USGS Publications Warehouse

    Persons, Trevor B.; Nowak, Erika M.

    2006-01-01

    As part of the National Park Service Inventory and Monitoring Program in the Mojave Network, we conducted an inventory of amphibians and reptiles at Death Valley National Park in 2002-04. Objectives for this inventory were to: 1) Inventory and document the occurrence of reptile and amphibian species occurring at DEVA, primarily within priority sampling areas, with the goal of documenting at least 90% of the species present; 2) document (through collection or museum specimen and literature review) one voucher specimen for each species identified; 3) provide a GIS-referenced list of sensitive species that are federally or state listed, rare, or worthy of special consideration that occur within priority sampling locations; 4) describe park-wide distribution of federally- or state-listed, rare, or special concern species; 5) enter all species data into the National Park Service NPSpecies database; and 6) provide all deliverables as outlined in the Mojave Network Biological Inventory Study Plan. Methods included daytime and nighttime visual encounter surveys, road driving, and pitfall trapping. Survey effort was concentrated in predetermined priority sampling areas, as well as in areas with a high potential for detecting undocumented species. We recorded 37 species during our surveys, including two species new to the park. During literature review and museum specimen database searches, we recorded three additional species from DEVA, elevating the documented species list to 40 (four amphibians and 36 reptiles). Based on our surveys, as well as literature and museum specimen review, we estimate an overall inventory completeness of 92% for Death Valley and an inventory completeness of 73% for amphibians and 95% for reptiles. Key Words: Amphibians, reptiles, Death Valley National Park, Inyo County, San Bernardino County, Esmeralda County, Nye County, California, Nevada, Mojave Desert, Great Basin Desert, inventory, NPSpecies.

  14. Development of a mobile application for amphibian species recognition

    NASA Astrophysics Data System (ADS)

    Parveen, B.; H, Chew T.; Shamsir, M. S.; Ahmad, N.

    2014-02-01

    The smartphones mobility and its pervasiveness are beginning to transform practices in biodiversity conservation. The integrated functionalities of a smartphone have created for the public and biodiversity specialists means to identify, gather and record biodiversity data while simultaneously creating knowledge portability in the digital forms of mobile guides. Smartphones enable beginners to recreate the delight of species identification usually reserved for specialist with years of experience. Currently, the advent of Android platform has enabled stakeholders in biodiversity to harness the ubiquity of this platform and create various types of mobile application or "apps" for use in biodiversity research and conservation. However, there is an apparent lack of application devoted to the identification in herpetofauna or amphibian science. Amphibians are a large class of animals with many different species still unidentified under this category. Here we describe the development of an app called Amphibian Recognition Android Application (ARAA) to identify frog amphibian species as well as an accompanying field guide. The app has the amphibian taxonomic key which assists the users in easy and rapid species identification, thus facilitating the process of identification and recording of species occurrences in conservation work. We will also present an overview of the application work flow and how it is designed to meet the needs a conservationist. As this application is still in its beta phase, further research is required to improve the application to include tools such automatic geolocation and geotagging, participative sensing via crowdsourcing and automated identification via image capture. We believe that the introduction of this app will create an impetus to the awareness of nature via species identification.

  15. Projected climate impacts for the amphibians of the western hemisphere

    USGS Publications Warehouse

    Lawler, Joshua J.; Shafer, Sarah L.; Bancroft, Betsy A.; Blaustein, Andrew R.

    2010-01-01

    Given their physiological requirements, limited dispersal abilities, and hydrologically sensitive habitats, amphibians are likely to be highly sensitive to future climatic changes. We used three approaches to map areas in the western hemisphere where amphibians are particularly likely to be affected by climate change. First, we used bioclimatic models to project potential climate-driven shifts in the distribution of 413 amphibian species based on 20 climate simulations for 2071–2100. We summarized these projections to produce estimates of species turnover. Second, we mapped the distribution of 1099 species with restricted geographic ranges. Finally, using the 20 future climate-change simulations, we mapped areas that were consistently projected to receive less seasonal precipitation in the coming century and thus were likely to have altered microclimates and local hydrologies. Species turnover was projected to be highest in the Andes Mountains and parts of Central America and Mexico, where, on average, turnover rates exceeded 60% under the lower of two emissions scenarios. Many of the restricted-range species not included in our range-shift analyses were concentrated in parts of the Andes and Central America and in Brazil's Atlantic Forest. Much of Central America, southwestern North America, and parts of South America were consistently projected to experience decreased precipitation by the end of the century. Combining the results of the three analyses highlighted several areas in which amphibians are likely to be significantly affected by climate change for multiple reasons. Portions of southern Central America were simultaneously projected to experience high species turnover, have many additional restricted-range species, and were consistently projected to receive less precipitation. Together, our three analyses form one potential assessment of the geographic vulnerability of amphibians to climate change and as such provide broad-scale guidance for directing

  16. Angiopoietin-1 enhances skeletal muscle regeneration in mice

    PubMed Central

    Mofarrahi, Mahroo; McClung, Joseph M.; Kontos, Christopher D.; Davis, Elaine C.; Tappuni, Bassman; Moroz, Nicolay; Pickett, Amy E.; Huck, Laurent; Harel, Sharon; Danialou, Gawiyou

    2015-01-01

    Activation of muscle progenitor cell myogenesis and endothelial cell angiogenesis is critical for the recovery of skeletal muscle from injury. Angiopoietin-1 (Ang-1), a ligand of Tie-2 receptors, enhances angiogenesis and skeletal muscle satellite cell survival; however, its role in skeletal muscle regeneration after injury is unknown. We assessed the effects of Ang-1 on fiber regeneration, myogenesis, and angiogenesis in injured skeletal muscle (tibialis anterior, TA) in mice. We also assessed endogenous Ang-1 levels and localization in intact and injured TA muscles. TA fiber injury was triggered by cardiotoxin injection. Endogenous Ang-1 mRNA levels immediately decreased in response to cardiotoxin then increased during the 2 wk. Ang-1 protein was expressed in satellite cells, both in noninjured and recovering TA muscles. Positive Ang-1 staining was present in blood vessels but not in nerve fibers. Four days after the initiation of injury, injection of adenoviral Ang-1 into injured muscles resulted in significant increases in in situ TA muscle contractility, muscle fiber regeneration, and capillary density. In cultured human skeletal myoblasts, recombinant Ang-1 protein increased survival, proliferation, migration, and differentiation into myotubes. The latter effect was associated with significant upregulation of the expression of the myogenic regulatory factors MyoD and Myogenin and certain genes involved in cell cycle regulation. We conclude that Ang-1 strongly enhances skeletal muscle regeneration in response to fiber injury and that this effect is mediated through induction of the myogenesis program in muscle progenitor cells and the angiogenesis program in endothelial cells. PMID:25608750

  17. Silica Aerogel Captures Cosmic Dust Intact

    NASA Technical Reports Server (NTRS)

    Tsou, P.

    1994-01-01

    The mesostructure of silica aerogel resembles stings of grapes, ranging in size from 10 to 100 angstrom. This fine mesostructure transmits nearly 90 percent of incident light in the visible, while providing sufficiently gentle dissipation of the kinetric energy of hypervelocity cosmic dust particles to permit their intact capture. We introduced silica aerogel in 1987 as capture medium to take advantage of its low density, fine mesostruicture and most importantly, its transparency, allowing optical location of captured micron sized particles.

  18. Multi-View Intact Space Learning.

    PubMed

    Xu, Chang; Tao, Dacheng; Xu, Chao

    2015-12-01

    It is practical to assume that an individual view is unlikely to be sufficient for effective multi-view learning. Therefore, integration of multi-view information is both valuable and necessary. In this paper, we propose the Multi-view Intact Space Learning (MISL) algorithm, which integrates the encoded complementary information in multiple views to discover a latent intact representation of the data. Even though each view on its own is insufficient, we show theoretically that by combing multiple views we can obtain abundant information for latent intact space learning. Employing the Cauchy loss (a technique used in statistical learning) as the error measurement strengthens robustness to outliers. We propose a new definition of multi-view stability and then derive the generalization error bound based on multi-view stability and Rademacher complexity, and show that the complementarity between multiple views is beneficial for the stability and generalization. MISL is efficiently optimized using a novel Iteratively Reweight Residuals (IRR) technique, whose convergence is theoretically analyzed. Experiments on synthetic data and real-world datasets demonstrate that MISL is an effective and promising algorithm for practical applications. PMID:26539856

  19. Measuring mitochondrial function in intact cardiac myocytes

    PubMed Central

    Dedkova, Elena N.; Blatter, Lothar A.

    2011-01-01

    Mitochondria are involved in cellular functions that go beyond the traditional role of these organelles as the power plants of the cell. Mitochondria have been implicated in several human diseases, including cardiac dysfunction, and play a role in the aging process. Many aspects of our knowledge of mitochondria stem from studies performed on the isolated organelle. Their relative inaccessibility imposes experimental difficulties to study mitochondria in their natural environment – the cytosol of intact cells – and has hampered a comprehensive understanding of the plethora of mitochondrial functions. Here we review currently available methods to study mitochondrial function in intact cardiomyocytes. These methods primarily use different flavors of fluorescent dyes and genetically encoded fluorescent proteins in conjunction with high-resolution imaging techniques. We review methods to study mitochondrial morphology, mitochondrial membrane potential, Ca2+ and Na+ signaling, mitochondrial pH regulation, redox state and ROS production, NO signaling, oxygen consumption, ATP generation and the activity of the mitochondrial permeability transition pore. Where appropriate we complement this review on intact myocytes with seminal studies that were performed on isolated mitochondria, permeabilized cells, and in whole hearts. PMID:21964191

  20. Radioimmunoassay for intact Gross mouse leukemia virus.

    PubMed Central

    Yalow, R S; Gross, L

    1976-01-01

    A radioimmunoassay for intact Gross leukemia virus has been developed using 125I-labeled Gross virus grown in tissue culture and guinea pig antisera to Gross virus grown either in tissue culture or harvested from leukemic C3H(f) mice. Separation of bound from free labeled virus was effected using the double antibody method. The assay can detect fewer than 10(8) virus particles and has been used to measure the viral content of individual organs from inoculated leukemic C3H(f) mice and from Ak mice with spontaneous leukemia. Organs from noninoculated healthy C3H(f) mice crossreacted poorly in the system, virus generally being detectable only in the thymus and spleen and at low concentration. In some of the inoculated C3H(f) leukemic mice the viral content of as little as 0.5 mul of plasma is measurable. That this assay is for intact virus and not for soluble antigens of the viral envelope was proven by the observation that the immunoreactive material of plasma and extracts from thymus and liver of leukemic mice has a buoyant denisty in sucrose of 1.17-1.18 g/ml, corresponding to that of intact virus grown in tissue culture. With this sensitivity it may now be possible to quantitate viral concentrations in tissue and body fluids from the time of inoculation through the development of obvious pathology. PMID:1066697

  1. Myocardin-related transcription factors are required for skeletal muscle development.

    PubMed

    Cenik, Bercin K; Liu, Ning; Chen, Beibei; Bezprozvannaya, Svetlana; Olson, Eric N; Bassel-Duby, Rhonda

    2016-08-01

    Myocardin-related transcription factors (MRTFs) play a central role in the regulation of actin expression and cytoskeletal dynamics. Stimuli that promote actin polymerization allow for shuttling of MRTFs to the nucleus where they activate serum response factor (SRF), a regulator of actin and other cytoskeletal protein genes. SRF is an essential regulator of skeletal muscle differentiation and numerous components of the muscle sarcomere, but the potential involvement of MRTFs in skeletal muscle development has not been examined. We explored the role of MRTFs in muscle development in vivo by generating mutant mice harboring a skeletal muscle-specific deletion of MRTF-B and a global deletion of MRTF-A. These double knockout (dKO) mice were able to form sarcomeres during embryogenesis. However, the sarcomeres were abnormally small and disorganized, causing skeletal muscle hypoplasia and perinatal lethality. Transcriptome analysis demonstrated dramatic dysregulation of actin genes in MRTF dKO mice, highlighting the importance of MRTFs in actin cycling and myofibrillogenesis. MRTFs were also shown to be necessary for the survival of skeletal myoblasts and for the efficient formation of intact myotubes. Our findings reveal a central role for MRTFs in sarcomere formation during skeletal muscle development and point to the potential involvement of these transcriptional co-activators in skeletal myopathies. PMID:27385017

  2. Calcium Signaling in Intact Dorsal Root Ganglia

    PubMed Central

    Gemes, Geza; Rigaud, Marcel; Koopmeiners, Andrew S.; Poroli, Mark J.; Zoga, Vasiliki; Hogan, Quinn H.

    2013-01-01

    Background Ca2+ is the dominant second messenger in primary sensory neurons. In addition, disrupted Ca2+ signaling is a prominent feature in pain models involving peripheral nerve injury. Standard cytoplasmic Ca2+ recording techniques use high K+ or field stimulation and dissociated neurons. To compare findings in intact dorsal root ganglia, we used a method of simultaneous electrophysiologic and microfluorimetric recording. Methods Dissociated neurons were loaded by bath-applied Fura-2-AM and subjected to field stimulation. Alternatively, we adapted a technique in which neuronal somata of intact ganglia were loaded with Fura-2 through an intracellular microelectrode that provided simultaneous membrane potential recording during activation by action potentials (APs) conducted from attached dorsal roots. Results Field stimulation at levels necessary to activate neurons generated bath pH changes through electrolysis and failed to predictably drive neurons with AP trains. In the intact ganglion technique, single APs produced measurable Ca2+ transients that were fourfold larger in presumed nociceptive C-type neurons than in nonnociceptive Aβ-type neurons. Unitary Ca2+ transients summated during AP trains, forming transients with amplitudes that were highly dependent on stimulation frequency. Each neuron was tuned to a preferred frequency at which transient amplitude was maximal. Transients predominantly exhibited monoexponential recovery and had sustained plateaus during recovery only with trains of more than 100 APs. Nerve injury decreased Ca2+ transients in C-type neurons, but increased transients in Aβ-type neurons. Conclusions Refined observation of Ca2+ signaling is possible through natural activation by conducted APs in undissociated sensory neurons and reveals features distinct to neuronal types and injury state. PMID:20526180

  3. High frequency oscillations in the intact brain

    PubMed Central

    Buzsáki, György; da Silva, Fernando Lopes

    2016-01-01

    High frequency oscillations (HFOs) constitute a novel trend in neurophysiology that is fascinating neuroscientists in general, and epileptologists in particular. But what are HFOs? What is the frequency range of HFOs? Are there different types of HFOs, physiological and pathological? How are HFOs generated? Can HFOs represent temporal codes for cognitive processes? These questions are pressing and this symposium volume attempts to give constructive answers. As a prelude to this exciting discussion, we summarize the physiological high frequency patterns in the intact brain, concentrating mainly on hippocampal patterns, where the mechanisms of high frequency oscillations are perhaps best understood. PMID:22449727

  4. Radiology of skeletal trauma

    SciTech Connect

    Rogers, L.F.

    1982-01-01

    This 1000-page book contains over 1700 illustrations, is presented in two volumes and subdivided into 23 chapters. After brief chapters of Introduction and General Anatomy, a section on Skeletal Biomechanics is presented. The Epidemiology of Fractures chapter examines, among other things, the effects of age on the frequency and distribution of fractures. In the chapter on Classifications of Fractures, the author describes the character of traumatic forces such as angulating, torsional, avulsive, and compressive, and then relates these to the resultant fracture configurations. The Fracture Treatment chapter presents an overview of treatment principles. Other chapters deal with specific problems in pediatric trauma, fracture healing and nonhealing, and fracture complications.

  5. Glucocorticoids and Skeletal Muscle.

    PubMed

    Bodine, Sue C; Furlow, J David

    2015-01-01

    Glucocorticoids are known to regulate protein metabolism in skeletal muscle, producing a catabolic effect that is opposite that of insulin. In many catabolic diseases, such as sepsis, starvation, and cancer cachexia, endogenous glucocorticoids are elevated contributing to the loss of muscle mass and function. Further, exogenous glucocorticoids are often given acutely and chronically to treat inflammatory conditions such as asthma, chronic obstructive pulmonary disease, and rheumatoid arthritis, resulting in muscle atrophy. This chapter will detail the nature of glucocorticoid-induced muscle atrophy and discuss the mechanisms thought to be responsible for the catabolic effects of glucocorticoids on muscle. PMID:26215994

  6. 50 CFR 622.38 - Landing fish intact.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 10 2011-10-01 2011-10-01 false Landing fish intact. 622.38 Section 622... § 622.38 Landing fish intact. The operator of a vessel that fishes in the EEZ is responsible for ensuring that fish on that vessel in the EEZ are maintained intact and, if taken from the EEZ,...

  7. 7 CFR 160.29 - Containers to remain intact.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Containers to remain intact. 160.29 Section 160.29... STANDARDS FOR NAVAL STORES Analysis, Inspection, and Grading on Request § 160.29 Containers to remain intact... the containers holding such naval stores remain intact as sampled until the analysis,...

  8. Toxicity of road salt to Nova Scotia amphibians.

    PubMed

    Collins, Sara J; Russell, Ronald W

    2009-01-01

    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(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. PMID:18684543

  9. Early 1900s Detection of Batrachochytrium dendrobatidis in Korean Amphibians

    PubMed Central

    Fong, Jonathan J.; Cheng, Tina L.; Bataille, Arnaud; Pessier, Allan P.; Waldman, Bruce; Vredenburg, Vance T.

    2015-01-01

    The pathogenic fungus Batrachochytrium dendrobatidis (Bd) is a major conservation concern because of its role in decimating amphibian populations worldwide. We used quantitative PCR to screen 244 museum specimens from the Korean Peninsula, collected between 1911 and 2004, for the presence of Bd to gain insight into its history in Asia. Three specimens of Rugosa emeljanovi (previously Rana or Glandirana rugosa), collected in 1911 from Wonsan, North Korea, tested positive for Bd. Histology of these positive specimens revealed mild hyperkeratosis – a non-specific host response commonly found in Bd-infected frogs – but no Bd zoospores or zoosporangia. Our results indicate that Bd was present in Korea more than 100 years ago, consistent with hypotheses suggesting that Korean amphibians may be infected by endemic Asian Bd strains. PMID:25738656

  10. Early 1900 s detection of Batrachochytrium dendrobatidis in Korean amphibians.

    PubMed

    Fong, Jonathan J; Cheng, Tina L; Bataille, Arnaud; Pessier, Allan P; Waldman, Bruce; Vredenburg, Vance T

    2015-01-01

    The pathogenic fungus Batrachochytrium dendrobatidis (Bd) is a major conservation concern because of its role in decimating amphibian populations worldwide. We used quantitative PCR to screen 244 museum specimens from the Korean Peninsula, collected between 1911 and 2004, for the presence of Bd to gain insight into its history in Asia. Three specimens of Rugosa emeljanovi (previously Rana or Glandirana rugosa), collected in 1911 from Wonsan, North Korea, tested positive for Bd. Histology of these positive specimens revealed mild hyperkeratosis - a non-specific host response commonly found in Bd-infected frogs - but no Bd zoospores or zoosporangia. Our results indicate that Bd was present in Korea more than 100 years ago, consistent with hypotheses suggesting that Korean amphibians may be infected by endemic Asian Bd strains. PMID:25738656