POPULATION STRUCTURE OF THE RED-SPOTTED TOAD, BUFO PUNCTATUS, IN A NATURALLY FRAGMENTED DESERT LANDSCAPE

EPA Science Inventory

We investigated the spatial scale at which genetic structure of Bufo punctatus within the Mojave

Desert is organized by sequencing a portion of mitochondrial DNA control region for 831 toads

collected from 43 sites around Las Vegas, Nevada. We grouped these collecti...

RADIATION-INDUCED GENETIC DAMAGE IN THE MEXICAN TOAD (BUFO VALLICEPS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blair, W.F.

1960-10-01

Lines of Mexican toads (Bufo valliceps) bearing x-ray induced genetic damage were established by mating normal females with males that had received gonadal x-ray doses ranging from 300 to 3000 r. Survival in the first generation was inversely proportional to dose,-as was expected. Toads of the 300-r and l000- r lines were inbred, and toads of these lines and of the 700-r line were outcrossed to normal ones. Two crosses were made between toads of the 500-r and 1000-r lines. Developmental abnormalities of various kinds appeared at life history stages rangthg from early embryonic development to post-metamorphic life in bothmore » inbred and outcross generations. These included abnormal gastrulation and neurulation, larval and post-metamorphic edema, abnormally positioned or missing limbs, optical deficiencies, prognathous jaw due to excessive elongation of the lower jaw, and melanin deficiency. The prognathous jaw, in its extreme expression, would probably be lethal in natural populations because of difficulty of feeding. The melanin deficiency, in its extreme expression, is lethal as metamorphosis fails to occur, and in lesser expression, it appears to be lethal or detrimental. The various abnormalities do not appear to be inherited in any simple way, but instead they vary in expression both within and between generations, possibly in relation to genotype and environment. (auth)« less

Selection of diet by metamorphic and juvenile western toads (Bufo boreas) in northeastern Oregon

Treesearch

Evelyn L Bull; Jane L. Hayes

2009-01-01

The decline of Bufo boreas, the Western Toad, in portions of its range has accentuated the need for more complete information on all life stages of this species. Our objectives were to describe the diet of recently metamorphosed and juvenile (one-year old) B. boreas and then compare it to the available arthropods. Metamorphs (n...

Common toads (Bufo arenarum) learn to anticipate and avoid hypertonic saline solutions.

PubMed

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

2007-11-01

Toads (Bufo arenarum) were exposed to pairings between immersion in a neutral saline solution (i.e., one that caused no significant variation in fluid balance), followed by immersion in a highly hypertonic saline solution (i.e., one that caused water loss). In Experiment 1, solutions were presented in a Pavlovian conditioning arrangement. A group receiving a single neutral-highly hypertonic pairing per day exhibited a greater conditioned increase in heart rate than groups receiving either the same solutions in an explicitly unpaired fashion, or just the neutral solution. Paired toads also showed a greater ability to compensate for water loss across trials than that of the explicitly unpaired group. Using the same reinforcers and a similar apparatus, Experiment 2 demonstrated that toads learn a one-way avoidance response motivated by immersion in the highly hypertonic solution. Cardiac and avoidance conditioning are elements of an adaptive system for confronting aversive situations involving loss of water balance. Copyright 2007 APA.

Membrane currents in the oocyte of the toad Bufo arenarum.

PubMed

Kotsias, Basilio A; Damiano, Alicia E; Godoy, Sebastian; Assef, Yanina; Ibarra, Cristina; Cantiello, Horacio F

2002-03-01

The amphibian oocyte cell model is widely used for heterologous expression of ionic channels and receptors. Little is known, however, about the physiology of oocyte cell models other than Xenopus laevis. In this study, the two-electrode voltage clamp technique was used to assess the most common electrical patterns of oocytes of the South American toad Bufo arenarum. Basal membrane resistance, resting potential, and ionic currents were determined in this cell model. The oocyte transmembrane resistance was 0.35 M(Omega), and the resting potential in normal saline was about -33 mV with a range between -20 mV and -50 mV. This is, to our knowledge, the first attempt to begin an understanding of the ion transport mechanisms of Bufo arenarum oocytes. This cell model may provide a viable alternative to the expression of ion channels, in particular those endogenously observed in Xenopus laevis oocytes. Copyright 2002 Wiley-Liss, Inc.

HABITAT PATCH OCCUPANCY BY THE RED-SPOTTED TOAD (BUFO PUNCTATUS) IN A NATURALLY FRAGMENTED, DESERT LANDSCAPE

EPA Science Inventory

Amphibians are often thought to have a metapopulation structure, which may render them vulnerable to habitat fragmentation. The red-spotted toad (Bufo panctatus) in the southwestern USA and Mexico commonly inhabits wetlands that have become much smaller and fewer since the la...

A light and electron microscopic study of Trypanosoma fallisi N. Sp. in toads (Bufo americanus) from Algonquin Park, Ontario.

PubMed

Martin, D S; Desser, S S

1990-01-01

Trypanosoma fallisi n. sp. is described from Bufo americanus in Ontario. The parasite was observed in 65 of 94 toads examined. The trypanosomes were pleomorphic with respect to the age of infections, being longer and broader in early infections (during spring and summer) and shorter and more slender during late summer and autumn. They ranged in size from 38-76 microns in body length and 3-8 microns in width, with a free flagellum 6-30 microns long. Epizootiological and experimental evidence suggests that this trypanosome is transmitted to the toads by the leech, Batracobdella picta. Trypanosoma fallisi is morphologically similar to T. bufophlebotomi described in Bufo boreas from California, but geographic isolation, host and vector differences as well as slight morphological differences indicate that speciation has occurred. Similar trypanosomes from Bufo americanus (which were identified as T. bufophlebotomi) in Michigan, are probably T. fallisi. This species shares many ultrastructural features with trypanosomes of other lower vertebrates and also of mammals.

Tropical cloud forest climate variability and the demise of the Monteverde golden toad

PubMed Central

Anchukaitis, Kevin J.; Evans, Michael N.

2010-01-01

Widespread amphibian extinctions in the mountains of the American tropics have been blamed on the interaction of anthropogenic climate change and a lethal pathogen. However, limited meteorological records make it difficult to conclude whether current climate conditions at these sites are actually exceptional in the context of natural variability. We use stable oxygen isotope measurements from trees without annual rings to reconstruct a century of hydroclimatology in the Monteverde Cloud Forest of Costa Rica. High-resolution measurements reveal coherent isotope cycles that provide annual chronological control and paleoclimate information. Climate variability is dominated by interannual variance in dry season moisture associated with El Niño Southern Oscillation events. There is no evidence of a trend associated with global warming. Rather, the extinction of the Monteverde golden toad (Bufo periglenes) appears to have coincided with an exceptionally dry interval caused by the 1986–1987 El Niño event. PMID:20194772

Toxicity of mine drainage to embryonic and larval boreal toads (Bufonidae: Bufo boreas)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porter, K.R.; Hakanson, D.E.

1976-05-17

Chemical analyses and bioassays of mine drainage were made to determine if it could be a factor accounting for the absence of amphibians from Clear Creek County, Colorado. The concentrations of hydrogen ion, iron, copper and zinc in the drainage were all individually much greater than the tolerance levels of premetamorphic toads. The lethality of the drainage was found to be of such a magnitude that it required diluting approximately one thousand times before larvae could survive in it. Boreal toad (Bufo boreas) larvae are more resistant to acidity than most fish but are very similar to other anuran larvaemore » and salmonids in their sensitivity to copper and zinc. (auth)« less

Hormonal priming, induction of ovulation and in-vitro fertilization of the endangered Wyoming toad (Bufo baxteri)

PubMed Central

Browne, Robert K; Seratt, Jessica; Vance, Carrie; Kouba, Andrew

2006-01-01

The endangered Wyoming toad (Bufo baxteri) is the subject of an extensive captive breeding and reintroduction program. Wyoming toads in captivity rarely ovulate spontaneously and hormonal induction is used to ovulate females or to stimulate spermiation in males. With hormonal induction, ovulation is unreliable and egg numbers are low. The sequential administration of anovulatory doses of hormones (priming) has increased egg numbers and quality in both anurans and fish. Consequently, we tested the efficacy of a combination of human Chorionic Gonadotrophin (hCG) and Luteinizing Hormone Releasing Hormone analogue (LHRHa) administered as one dose, or two or three sequential doses to Bufo baxteri on egg numbers, fertilization and early embryo development. Spawning toads deposited eggs into Simplified Amphibian Ringers (SAR) solution to enable controlled in-vitro fertilization (IVF) with sperm from hormonally induced male toads. Unprimed females receiving a single mixed normally ovulatory dose of 500 IU hCG plus 4 micrograms of LHRHa produced no eggs. Whereas females primed with this dose and an anovulatory dose (100 IU hCG and 0.8 micrograms of LHRHa) of the same hormones, or primed only with an anovulatory dose, spawned after then receiving an ovulatory dose. Higher total egg numbers were produced with two primings than with one priming. Moreover, two primings produced significantly more eggs from each individual female than one priming. The cleavage rate of eggs was not found to differ between one or two primings. Nevertheless, embryo development with eggs from two primings gave a significantly greater percentage neurulation and swim-up than those from one priming. Of the male toads receiving a single dose of 300 IU hCG, 80% produced spermic urine with the greatest sperm concentration 7 hours post-administration (PA). However, peak sperm motility (95%) was achieved at 5 hours PA and remained relatively constant until declining 20 hours PA. In conclusion, Bufo baxteri

METAPOPULATION PROCESSES OF INFINITE DISPERSAL?: HABITAT PATCH OCCUPANCY BY TOADS (BUFO PUNCTATUS) IN A NATURALLY FRAGMENTED DESERT

EPA Science Inventory

Amphibians are often thought to have a metapopulation structure, which may render them vulnerable to habitat fragmentation. The red-spotted toad (Bufo punctatus) in the southwestern USA and Mexico commonly inhabits wetlands that have become much smaller and fewer since the late P...

Circulating catecholamine and glucose concentrations in Japanese toads (Bufo japonicus) during the breeding season.

PubMed

Wilson, J X; Sawai, H; Kikuchi, M; Kubokawa, K; Ishii, S

1995-06-01

We investigated the relationship between catecholamine neurohormones and glucose during seasonal reproductive activity in Japanese toads (Bufo japonicus). Field studies found that plasma epinephrine concentration increased as toads migrated to their breeding ponds, where amplexus most frequently took place. Blood glucose concentration also increased as toads arrived at the ponds, even though these animals did not eat during the breeding season, and there was a positive correlation between epinephrine and glucose levels. Blood glucose concentration was higher in amplectic than in solitary males, whereas this relationship did not occur in females. For both males and females, plasma epinephrine concentration was elevated during amplexus. The plasma concentration of norepinephrine was lower than that of epinephrine and did not correlate with either the proximity of the animal to the breeding ponds or the blood glucose concentration. Laboratory experiments showed that systemic injection of [Trp7,Leu8]gonadotropin-releasing hormone (sGnRH) increased plasma epinephrine to levels characteristic of amplectic feral toads. These results suggest that a physiological role of GnRH-like peptides may be to stimulate epinephrine secretion and consequently to increase glucose production in toads under the starvation conditions associated with the breeding migration.

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

PubMed

Petrovan, Silviu O; Schmidt, Benedikt R

2016-01-01

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

Abundance and reproduction of toads (Bufo) along a regulated river in the southwestern United States: Importance of flooding in riparian ecosystems

Treesearch

H. L. Bateman; M. J. Harner; A. Chung-MacCoubrey

2008-01-01

Abundance and size of toads (Bufo woodhousii and B. cognatus) were related to precipitation, river flow, and groundwater over 7 years along the Middle Rio Grande, a regulated river in the semi-arid southwestern United States. Toads were monitored in riparian areas at 12 sites spanning 140 km of river during summers 2000­2006....

Experimental repatriation of boreal toad (Bufo boreas) eggs, metamorphs, and adults in Rocky Mountain National Park

USGS Publications Warehouse

Muths, E.; Johnson, T.L.; Corn, P.S.

2001-01-01

The boreal toad (Bufo boreas) is an endangered species in Colorado and is considered a candidate species for federal listing by the United States Fish and Wildlife Service. Boreal toads are absent from many areas of suitable habitat in the Southern Rocky Mountains of Colorado presumably due to a combination of causes. We moved boreal toads from existing populations and from captive rearing facilities to habitat which was historically, but is not currently, occupied by toads to experimentally examine methods of repatriation for this species. Repatriation is defined as the release of individuals into areas currently of historically occupied by that species (Dodd and Seigel, 1991). This effort was in response to one of the criteria for delisting the boreal toad in Colorado stated in the conservation plan and agreement for the management and recovery of the Southern Rocky Mountain population of the boreal toad (Loeffler, 1998:16); "...there must be at least 2 viable breeding populations of boreal toads in each of at least 9 of 11 mountain ranges of its historic distribution." Without moving eggs from established wild populations, or from captivity to historical localities, it is doubtful whether the recovery team will attain this ambitions goal.

Movements and habitat use of Yosemite toads (Anaxyrus (formerly Bufo) canorus) in the Sierra National Forest, California

Treesearch

Christina T. Liang

2013-01-01

The Yosemite Toad (Anaxyrus (Bufo) canorus) is a high-elevation species endemic to the central Sierra Nevada mountain range in California whose populations are in decline. There is limited information on their terrestrial movement and habitat use, which impairs our understanding of the ecology and habitat...

Sensitivity of toad tadpoles, Bufo melanostictus (Schneider), to heavy metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khangarot, B.S.; Ray, P.K.

1987-03-01

Amphibian larval stages have several qualities which make them as a useful indicator of harmful levels of pollutants in bioassay tests. Amphibian tadpoles show a variety of sublethal responses such as changes in growth, development rates, pigmentation and expression of morphological deformities in a lesser time of exposure to the environmental pollutants. The objective of the work reported in this paper was to determine the acute toxicity of cadmium, copper, chromium, mercury, nickel, silver and zinc to the tadpoles of toad Bufo melanostictus (Schneider), which is commonly available and breed in aquatic habitats exhibiting a wide range of temperature andmore » varying water quality.« less

METAPOPULATION PROCESSES OR INFINITE DISPERSAL?: HABITAT PATCH OCCUPANCY BY TOADS (BUFO PUNCTATUS) IN A NATURALLY FRAGMENTED DESERT LANDSCAPE

EPA Science Inventory

Amphibians are often thought to have a metapopulation structure, which may render them vulnerable to habitat fragmentation. The red-spotted toad (Bufo punctatus) in the southwestern USA and Mexico commonly inhabits wetlands that have become much smaller and fewer since the late P...

METAPOPULATION PROCESSES OF INFINITE DISPERSAL: HABITAT PATCH OCCUPANCY BY TOADS (BUFO PUNCTATUS) IN A NATURALLY FRAGMENTED DESERT LANDSCAPE

EPA Science Inventory

Amphibians are often thought to have a metapopulation structure, which may render them vulnerable to habitat fragmentation. The red-spotted toad (Bufo punctatus) in the southwestern USA and Mexico commonly inhabits wetlands that have become much smaller and fewer since the late P...

METAPOPULATION PROCESSES OR INFINITE DISPERSAL?: HABITAT PATCH OCCUPANCY BY TOADS (BUFO PUNCTATUS) IN A NAUTRALLY FRAGMENTED DESERT LANDSCAPE

EPA Science Inventory

Amphibians are often thought to have a metapopulation structure, which may render them vulnerable to habitat fragmentation. The red-spotted toad (Bufo punctatus) in the southwestern USA and Mexico commonly inhabits wetlands that have become much smaller and fewer since the late P...

Molecular phylogenetics and historical biogeography of the west-palearctic common toads (Bufo bufo species complex).

PubMed

Garcia-Porta, J; Litvinchuk, S N; Crochet, P A; Romano, A; Geniez, P H; Lo-Valvo, M; Lymberakis, P; Carranza, S

2012-04-01

In most pan-Eurasiatic species complexes, two phenomena have been traditionally considered key processes of their cladogenesis and biogeography. First, it is hypothesized that the origin and development of the Central Asian Deserts generated a biogeographic barrier that fragmented past continuous distributions in Eastern and Western domains. Second, Pleistocene glaciations have been proposed as the main process driving the regional diversification within each of these domains. The European common toad and its closest relatives provide an interesting opportunity to examine the relative contributions of these paleogeographic and paleoclimatic events to the phylogeny and biogeography of a widespread Eurasiatic group. We investigate this issue by applying a multiproxy approach combining information from molecular phylogenies, a multiple correspondence analysis of allozyme data and species distribution models. Our study includes 304 specimens from 164 populations, covering most of the distributional range of the Bufo bufo species complex in the Western Palearctic. The phylogenies (ML and Bayesian analyses) were based on a total of 1988 bp of mitochondrial DNA encompassing three genes (tRNAval, 16S and ND1). A dataset with 173 species of the family Bufonidae was assembled to estimate the separation of the two pan-Eurasiatic species complexes of Bufo and to date the main biogeographic events within the Bufo bufo species complex. The allozyme study included sixteen protein systems, corresponding to 21 presumptive loci. Finally, the distribution models were based on maximum entropy. Our distribution models show that Eastern and Western species complexes are greatly isolated by the Central Asian Deserts, and our dating estimates place this divergence during the Middle Miocene, a moment in which different sources of evidence document a major upturn of the aridification rate of Central Asia. This climate-driven process likely separated the Eastern and Western species. At the

Localization of water channels in the skin of two species of desert toads, Anaxyrus (Bufo) punctatus and Incilius (Bufo) alvarius.

PubMed

Shibata, Yuki; Takeuchi, Hiro-Aki; Hasegawa, Takahiro; Suzuki, Masakazu; Tanaka, Shigeyasu; Hillyard, Stanley D; Nagai, Takatoshi

2011-09-01

Anuran amphibians obtain water by osmosis across their ventral skin. A specialized region in the pelvic skin of semiterrestrial species, termed the seat patch, contains aquaporins (AQPs) that become inserted into the apical plasma membrane of the epidermis following stimulation by arginine vasotocin (AVT) to facilitate rehydration. Two AVT-stimulated AQPs, AQP-h2 and AQP-h3, have been identified in the epidermis of seat patch skin of the Japanese tree frog, Hyla japonica, and show a high degree of homology with those of bufonid species. We used antibodies raised against AQP-h2 and AQP-h3 to characterize the expression of homologous AQPs in the skin of two species of toads that inhabit arid desert regions of southwestern North America. Western blot analysis of proteins gave positive results for AQP-h2-like proteins in the pelvic skin and also the urinary bladder of Anaxyrus (Bufo) punctatus while AQP-h3-like proteins were found in extracts from the pelvic skin and the more anterior ventral skin, but not the urinary bladder. Immunohistochemical observations showed both AQP-h2- and AQP-h3-like proteins were present in the apical membrane of skin from the pelvic skin of hydrated and dehydrated A. punctatus. Further stimulation by AVT or isoproterenol treatment of living toads was not evident. In contrast, skin from hydrated Incilius (Bufo) alvarius showed very weak labeling of AQP-h2- and AQP-h3-like proteins and labeling turned intense following stimulation by AVT. These results are similar to those of tree frogs and toads that occupy mesic habitats and suggest this pattern of AQP expression is the result of phylogenetic factors shared by hylid and bufonid anurans.

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

PubMed

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

2014-09-01

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

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

USGS Publications Warehouse

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

2001-01-01

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

Sexual differences in the post-breeding movements and habitats selected by Western toads (Bufo boreas) in southeastern Idaho

USGS Publications Warehouse

Bartelt, Paul E.; Peterson, Charles R.; Klaver, Robert W.

2004-01-01

We used radio-telemetry to study the movements and habitat use of Western toads (Bufo boreas) in the Targhee National Forest in southeastern Idaho. Eighteen toads (10 male and 8 female) that bred in a seasonally flooded pond, were fitted with radio-transmitters, tracked, and their movements mapped and analyzed with global positioning and geographic information systems. We also analyzed their patterns of habitat selection at micro- and macro-scales by comparing sites used by toads with randomly selected sites. After breeding, two male and six female toads left the breeding pond and used terrestrial habitats extensively. Male and female toads showed different patterns of movement and habitat use, although all toads seemed to behave in ways that reduced loss of body water (e.g., such as traveling on nights of high humidity). Male toads traveled shorter distances from the pond than females (581 ± 98 m and 1105 ± 272 m, respectively). Female toads used terrestrial habitats extensively and were selective of cover types (e.g., shrub) that provided greater protection from dehydration. Female toads also preferred certain habitat edges and open forests over forests with closed canopies or clearcuts. Information from this study can assist land managers in establishing protective buffers and managing forests for the protection of toad populations.

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

Treesearch

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

2004-01-01

In the southeastern United States, coarse woody debris (CWD) typically harbors high densities of invertebrates. However, its importance as a foraging substrate for southeastern amphibians is relatively unknown. We examined effects of CWD manipulations on diet composition of southern toads (Bufo tmrestns) in upland loblolly pine (Pinus taeda) stands...

Factors limiting the recovery of boreal toads (Bufo b. boreas)

USGS Publications Warehouse

Carey, C.; Corn, P.S.; Jones, M.S.; Livo, L.J.; Muths, E.; Loeffler, C.W.; Lannoo, M.

2005-01-01

Boreal toads (Bufo b. boreas) are widely distributed over much of the mountainous western United States. Populations in the Southern Rocky Mountains suffered extensive declines in the late 1970s through early 1980s (Carey, 1993). At the time, these mass mortalities were thought to be associated with a bacterial infection (Carey, 1993). Although the few populations that survived the mass die-offs were not systematically monitored until at least 1993, no mass mortalities had been observed until 1996 when die-offs were observed. A mycotic skin infection associated with a chytrid fungus is now causing mortality of toads in at least two of the populations (M.S. Jones and D.E. Green, unpublished data; Muths et al., 2003). Boreal toads are now absent throughout large areas of their former distribution in Colorado and southern Wyoming and may be extinct in New Mexico (Corn et al., 1989; Carey, 1993; Stuart and Painter, 1994). These toads are classified as “endangered” by Colorado and New Mexico and are designated as a protected non-game species in Wyoming. The U.S. Fish and Wildlife Service has categorized the Southern Rocky Mountain populations for federal listing and is currently reviewing their designation as a “warranted but precluded” species for possible listing in the next few years. For the management of boreal toads and their habitats, a Boreal Toad Recovery Team was formed by the Colorado Division of Wildlife in 1995 as part of a collaborative effort with federal agencies within the United States’ departments of the Interior and Agriculture and with agencies in two adjoining states. To date, conservation agreements have been signed by eight state and federal agencies and by the Colorado Natural Heritage Program. Although boreal toads were considered common throughout their range in Colorado, no comprehensive surveys of the numbers and sizes of their populations were conducted prior to mass die-offs in the 1970s. Surveys completed in the late 1980s to

Heterogeneity and lability of endogenous digitalis-like substances in the plasma of the toad, Bufo marinus.

PubMed

Butler, V P; Morris, J F; Akizawa, T; Matsukawa, M; Keating, P; Hardart, A; Furman, I

1996-08-01

Three major groups of endogenous digitalis-like substances (EDLS) have been identified in the plasma of the toad, Bufo marinus. One group of compounds, present in fresh plasma, is composed of chromatographically homogeneous polar conjugates, principally bufadienolide 3-sulfates, which exhibit relatively weak Na(+)-K(+)-adenosinetriphosphatase (ATPase) inhibitory activity. A second and larger group of compounds, also found in fresh plasma, includes chromatographically heterogeneous conjugates, which are effective inhibitors of Na(+)-K(+)-ATPase; these compounds possess properties similar to those of bufotoxins. The third group of EDLS consists of free unconjugated bufadienolides, which are also effective Na(+)-K(+)-ATPase inhibitors. These unconjugated bufadienolides are present in relatively low concentrations in fresh toad plasma, but appreciable quantities are enzymatically generated from conjugates (believed to consist principally of bufotoxins) during the in vitro incubation of plasma. We suggest that the extent to which circulating polar EDLS are enzymatically deconjugated in vivo may be important in the regulation of the digitalis-sensitive Na(+)-K(+)-ATPase of toad brain, the only known digitalis-sensitive Na(+)-K(+)-ATPase in the toad.

Wildfire effects on water temperature and selection of breeding sites by the boreal toad (Bufo boreas) in seasonal wetlands

Treesearch

Blake R. Hossack; Paul Stephen Corn

2008-01-01

Disturbances can significantly affect the thermal regime and community structure of wetlands. We investigated the effect of a wildfire on water temperature of seasonal, montane wetlands after documenting the colonization of recently burned wetlands by the Boreal Toad (Bufo boreas boreas). We compared the daily mean temperature, daily maximum...

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

PubMed

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

2007-12-01

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

Post-breeding habitat use by adult boreal toads (Bufo boreas boreas) after wildfire in Glacier National Park, USA

Treesearch

C. Gregory Guscio; Blake R. Hossack; Lisa A. Eby; Paul Stephen Corn

2008-01-01

Effects of wildfire on amphibians are complex, and some species may benefit from the severe disturbance of stand-replacing fire. Boreal Toads (Bufo boreas boreas) in Glacier National Park, Montana, USA increased in occurrence after fires in 2001 and 2003. We used radio telemetry to track adult B. boreas in a mosaic of terrestrial...

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

PubMed Central

Hanner, R H; Ryan, G B

1980-01-01

Renal juxtaglomerular regions were examined in the axolotl (Ambystoma mexicanum and toad (Bufo marinus). Prominent granulated peripolar epithelial cells were found surrounding the origin of the glomerular tuft in the axolotl. These cells resembled the peripolar cells recently discovered in mammalian species. They contained multiple electron-dense cytoplasmic granules, some of which showed a paracrystalline substructure and signs of exocytoxic activity. Such cells were difficult to find and smaller in the toad. In contrast, granulated juxtaglomerular arteriolar myoephithelial cells were much more readily found and larger in the toad than in the axolotl. No consistent differences were noted in juxtaglomerular cells or their granules in response to changes in environmental chloride concentration. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 PMID:7410189

Phospholipid transfer activities in toad oocytes and developing embryos. [Bufo arenarum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rusinol, A.; Salomon, R.A.; Bloj, B.

1987-01-01

The role of lipid transfer proteins during plasma membrane biogenesis was explored. Developing amphibia embryos were used because during their growth an active plasma membrane biosynthesis occurs together with negligible mitochondrial and endoplasmic reticulum proliferation. Sonicated vesicles, containing /sup 14/C-labeled phospholipids and /sup 3/H-labeled triolein, as donor particles and cross-linked erythrocyte ghosts as acceptor particles were used to measure phospholipid transfer activities in unfertilized oocytes and in developing embryos of the toad Bufo arenarum. Phosphatidylcholine transfer activity in pH 5.1 supernatant of unfertilized oocytes was 8-fold higher than the activity found in female toad liver supernatant, but dropped steadily aftermore » fertilization. After 20 hr of development, at the stage of late blastula, the phosphatidylcholine transfer activity had dropped 4-fold. Unfertilized oocyte supernatant exhibited phosphatidylinositol and phosphatidylethanolamine transfer activity also, but at the late blastula stage the former had dropped 18-fold and the latter was no longer detectable under our assay conditions. Our results show that fertilization does not trigger a phospholipid transport process catalyzed by lipid transfer proteins. Moreover, they imply that 75% of the phosphatidylcholine transfer activity and more than 95% of the phosphatidylinositol and phosphatidylethanolamine transfer activities present in pH 5.1 supernatants of unfertilized oocytes may not be essential for toad embryo development. Our findings do not rule out, however, that a phosphatidylcholine-specific lipid transfer protein could be required for embryo early growth.« less

Concordant morphological and molecular clines in a contact zone of the Common and Spined toad (Bufo bufo and B. spinosus) in the northwest of France.

PubMed

Arntzen, Jan W; Trujillo, Tania; Butôt, Roland; Vrieling, Klaas; Schaap, Onno; Gutiérrez-Rodríguez, Jorge; Martínez-Solano, Iñigo

2016-01-01

Hybrid zones are regions where individuals of two species meet and produce hybrid progeny, and are often regarded as natural laboratories to understand the process of species formation. Two microevolutionary processes can take place in hybrid zones, with opposing effects on population differentiation. Hybridization tends to produce genetic homogenization, reducing species differences, whereas the presence of mechanisms of reproductive isolation result in barriers to gene flow, maintaining or increasing differences between taxa. Here we study a contact zone between two hybridizing toad species, Bufo bufo and B. spinosus , through a combination of molecular (12 polymorphic microsatellites, four nuclear and two mitochondrial SNP markers) and morphological data in a transect in the northwest of France. The results show largely concordant clines across markers, defining a narrow hybrid zone of ca. 30 km wide. Most hybrids in the centre of the contact zone are classified as F 2 or backcrossed individuals, with no individuals assigned to the F 1 hybrid class. We discuss the implications of these results for our understanding of the evolutionary history of these species. We anticipate that the toad contact zone here described will become an important asset in the study of hybrid zone dynamics and evolutionary biology because of its easy access and the abundance of the species involved.

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

USGS Publications Warehouse

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

2009-01-01

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

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

NASA Astrophysics Data System (ADS)

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

2016-04-01

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

Chronic exposure to coal fly ash causes minimal changes in corticosterone and testosterone concentrations in male southern toads Bufo terrestris

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, C.K.; Mendonca, M.T.

More than 50% of the electricity in the United States is produced by coal-burning power plants. The byproduct of coal-burning plants is coal fly ash, which contains increased concentrations of trace metals and is disposed of in collection basins. Southern toads (Bufo terrestris) frequently use these basins for reproduction. Male toads were collected in spring 2001 and 2002 from an ash basin and a reference site and divided into four groups: toads collected at the control site and maintained on (1) control substrate and food or (2) ash and contaminated food and toads collected at the ash site and maintainedmore » in (3) control or (4) ash conditions. Blood was collected periodically during 5 months to determine testosterone and corticosterone concentrations. Reference to ash toads exhibited a significant, transient increase in corticosterone at 4 weeks, but neither corticosterone nor testosterone continued to increase beyond this time. In contrast, toads caught and maintained on ash did not exhibit increased corticosterone. Testosterone in these toads appeared to be unrelated to ash exposure. This unexpected lack of a corticosterone response and no effect on testosterone suggests that toads chronically exposed to trace metals can acclimate to a polluted environment, but they may still experience subtle long-term consequences.« less

CRYPTIC NEOGENE VICARIANCE AND QUATERNARY DISPERSAL OF THE RED-SPOTTED TOAD (BUFO PUNCTATUS) INSIGHTS ON THE EVOLUTION OF NORTH AMERICAN WARM DESERT BIOTAS

EPA Science Inventory

We define the geographic distributions of embedded evolutionary mitochondrial DNA (mtDNA) lineages (clades) within a broadly distributed, arid- dwelling toad, Bufo punctatus, and evaluate these patterns as they relate to hypothesized vicariant events leading to the formation of b...

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

USGS Publications Warehouse

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

2008-01-01

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

Demography of common toads after local extirpation of co-occurring midwife toads

USGS Publications Warehouse

Bosch, Jaime; Fernandez-Beaskoetxea, S; Scherer, R.; Amburgey, Staci; Muths, Erin L.

2014-01-01

Estimating demographic parameters like survival or recruitment provides insight into the state and trajectory of populations, but understanding the contexts influencing those parameters, including both biotic and abiotic factors, is particularly important for management and conservation. At a high elevation national park in Central Spain, common toads (Bufo bufo) are apparently taking advantage of the near-extirpation of the midwife toad (Alytes obstetricans), as colonization into new breeding ponds is evident. Within this scenario, we expected demographic parameters of common toad populations tobe affected favorably by the putative release from competition. However, we found the population growth rate was negative in 4 of 5 years at the long-standing population; survival probability at the long-standing population and newly-colonised breeding ponds was lower than reported for other toads living at high elevations and the probability of recruitment was inadequate to compensate for the survival rate in maintaining a positive trajectory for either of the breeding ponds. We assessed weather covariates and disease for their contribution to the context that may be limiting the common toad’s successful use of the niche vacated by the midwife toad.

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

USGS Publications Warehouse

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

2004-01-01

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

Seasonal changes in the preferred body temperature, cardiovascular, and respiratory responses to hypoxia in the toad, Bufo paracnemis.

PubMed

Bícego-Nahas, K C; Gargaglioni, L H; Branco, L G

2001-05-01

Estivation is accompanied by a reduction of oxygen consumption in amphibians during drought. We tested the hypothesis that, during the dry season, the toad Bufo paracnemis selects a lower preferred body temperature (T(b)), and would be less sensitive to hypoxia, than during its active period. Therefore, during winter (dry season in São Paulo state, Brazil) and summer, we measured the effects of hypoxia (7% inspired O(2)) on preferred T(b). Additionally, pulmonary ventilation, heart rate, blood pressure, and oxygen consumption were also measured in toads at 15 and 25 degrees C. Blood gases were measured at 25 degrees C. Oxygen consumption was significantly higher during summer in toads at 25 degrees C. Under normoxia, preferred T(b) was higher during summer than during winter, and hypoxia caused a drop in preferred T(b) during both seasons. In both seasons, toads at 15 degrees C showed reduced pulmonary ventilation, heart rate, and blood pressure, and hypoxia had no effect. At 25 degrees C during summer only, hypoxia caused an increase in ventilation. Season had no effect on blood gases. We conclude that B. paracnemis displays an endogenous seasonal pattern of thermoregulation and control of ventilation. The decreased preferred T(b) and the physiological responses to hypoxia may be beneficial to toads encountering drought and when food is not available.

Structure and function of the undulating membrane in spermatozoan propulsion in the toad Bufo marinus

PubMed Central

1980-01-01

Accessory fibers in most sperm surround the axoneme so that their function in propulsion is difficult to assess. In the sperm of the toad Bufo marinus, an accessory fiber is displaced from the axoneme, being connected to it by the thin undulating membrane in such a way that the movement of axoneme and accessory fiber can be viewed independently. The axoneme is highly convoluted in whole mounts, and the axial fiber is straight. Cinemicrographic analysis shows that it is the longer, flexuous fiber, the presumed axoneme, that move actively. The accessory fiber follows it passively with a lower amplitude of movement. The accessory fiber does not move independent of the axoneme, even after demembranation and reactivation of the sperm. On the basis of anatomical relations in the neck region, it appears that the accessory fibers of amphibians are analogous to the dense fibers of mammalian sperm. SDS polyacrylamide gel electrophoresis of demembranated toad sperm tails reveals two principal proteins in addition to the tubulins, the former probably arising from the accessory fibers and the matrix of the undulating membrane. The function of displacing an accessory fiber into an undulating membrane may be to provide stiffness for the tail without incurring an energy deficit large enough to require a long middle piece. A long middle piece is not present in toad sperm, in contrast to those sperm that have accessory fibers around the axoneme. However, the toad sperm suffers a reduction in speed of about one- third, compared with the speed expected for a sperm without an undulating membrane. PMID:6771299

Digitalis-like compounds in the toad Bufo viridis: tissue and plasma levels and significance in osmotic stress.

PubMed

Lichtstein, D; Gati, I; Haver, E; Katz, U

1992-01-01

Digitalis-like compounds (DLC), constituents of animal tissues, are possible regulators of the Na+, K(+)-ATPase implicated in water and salt homeostasis. The distribution of DLC in the toad (Bufo viridis) was determined following methanol extraction and partial purification. DLC highest levels were found in the skin but it was also detected in the plasma and many internal organs. Short term (hours) exposure of the toad to hypertonic shock (1.5% NaCl) induced an increase in plasma osmolarity due to an increase in Na+ and Cl- levels. This treatment induced a transient, three fold, increase of DLC levels in the brain and transient reduction of its levels in the ventral skin. Acclimation of the toads to burrowing conditions for six weeks resulted in an increase in plasma osmolarity due to a large increase in plasma urea with a small increase in ion concentrations. Under these conditions DLC levels in the dorsal skin increased by 100% without alteration of its levels in the plasma, brain and ventral skin. DLC levels in the toad brain of control animals, showed a significant dependence on season, being highest in the summer and lowest in the winter. DLC levels in the skin peaked in May while the levels in the plasma were season independent. The changes in DLC levels induced by the short- as well as long-term perturbations in the animal environmental salinity together with the seasonal differences suggest that DLC in the toad is involved in water and salt homeostasis of these animals, but may also participate in other unknown functions.

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

PubMed

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

2016-11-01

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

How complex is the Bufo bufo species group?

PubMed

Arntzen, Jan W; Recuero, Ernesto; Canestrelli, Daniele; Martínez-Solano, Iñigo

2013-12-01

Species delineation remains one of the most challenging tasks in the study of biodiversity, mostly owing to the application of different species concepts, which results in contrasting taxonomic arrangements. This has important practical consequences, since species are basic units in fields like ecology and conservation biology. We here review molecular genetic evidence relevant to the systematics of toads in the Bufo bufo species group (Anura, Bufonidae). Two studies recently published in this journal (Recuero et al., MPE 62: 71-86 and García-Porta et al., MPE 63: 113-130) addressed this issue but reached opposing conclusions on the taxonomy of the group (four versus two species). In particular, allozyme data in the latter paper were interpreted as evidence for hybridization across species (between B. bufo-B. spinosus and B. bufo-B. verrucosissimus). We tested claims for hybridization through re-analysis of allozyme data for individuals instead of populations, to be able to distinguish between sympatry with and without admixture, and found no evidence of hybridization across taxa. We propose alternative explanations for the observed patterns that García-Porta et al. (2012) failed to consider. In the absence of unequivocal evidence for hybridization and introgression, we reject the proposal to downgrade Bufo spinosus and Bufo verrucosissimus to the subspecies level. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

Modeling amphibian energetics, habitat suitability, and movements of western toads, Anaxyrus (=Bufo) boreas, across present and future landscapes

USGS Publications Warehouse

Bartelt, Paul E.; Klaver, Robert W.; Porter, Warren P.

2010-01-01

Effective conservation of amphibian populations requires the prediction of how amphibians use and move through a landscape. Amphibians are closely coupled to their physical environment. Thus an approach that uses the physiological attributes of amphibians, together with knowledge of their natural history, should be helpful. We used Niche Mapper™ to model the known movements and habitat use patterns of a population of Western toads (Anaxyrus (=Bufo) boreas) occupying forested habitats in southeastern Idaho. Niche Mapper uses first principles of environmental biophysics to combine features of topography, climate, land cover, and animal features to model microclimates and animal physiology and behavior across landscapes. Niche Mapper reproduced core body temperatures (Tc) and evaporation rates of live toads with average errors of 1.6 ± 0.4 °C and 0.8 ± 0.2 g/h, respectively. For four different habitat types, it reproduced similar mid-summer daily temperature patterns as those measured in the field and calculated evaporation rates (g/h) with an average error rate of 7.2 ± 5.5%. Sensitivity analyses indicate these errors do not significantly affect estimates of food consumption or activity. Using Niche Mapper we predicted the daily habitats used by free-ranging toads; our accuracy for female toads was greater than for male toads (74.2 ± 6.8% and 53.6 ± 15.8%, respectively), reflecting the stronger patterns of habitat selection among females. Using these changing to construct a cost surface, we also reconstructed movement paths that were consistent with field observations. The effect of climate warming on toads depends on the interaction of temperature and atmospheric moisture. If climate change occurs as predicted, results from Niche Mapper suggests that climate warming will increase the physiological cost of landscapes thereby limiting the activity for toads in different habitats.

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

PubMed

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

2016-04-01

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

Characterization and quantification of corticosteroid-binding globulin in a southern toad, Bufo terrestris, exposed to coal-combustion-waste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, C.K.; Fontes, C.; Breuner, C.W.

2007-05-15

Corticosteroid-binding globulin (CBG) is a plasma protein that binds corticosterone and may regulate access of hormone to tissues. The role of CBG during a stress response is not clear. In this study, southern toads, Bufo terrestris, were exposed to a chronic pollutant (coal-combustion-waste), to determine changes in CBG and free corticosterone levels. Since toads exposed to chronic pollutants in previous studies did not exhibit the predicted changes in metabolic rate and mass, but did experience a significant elevation in total corticosterone, we hypothesized that CBG would likewise increase and thus, mitigate the effects of a chronic (i.e. 2 months) pollutantmore » stressor. To conduct this study, we first characterized the properties of CBG in southern toads. After characterization, we monitored the changes in CBG, total corticosterone, and free corticosterone in male toads that were exposed to either coal-combustion-waste or control conditions. CBG increased in all groups throughout the experiment. Total corticosterone, on the other hand, was only significantly elevated at four weeks of exposure to coal-combustion-waste. The increase in CBG did not parallel the increase in total corticosterone; as a result, free corticosterone levels were not buffered by CBG, but showed a peak at four weeks similar to total corticosterone. This finding indicates that, in this species, CBG may not provide a protective mechanism during long-term pollution exposure.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2005-04-01

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

Isolation and characterization of novel endogenous digitalis-like factors in the ovary of the giant toad, Bufo marinus.

PubMed

Matsukawa, M; Mukai, T; Akizawa, T; Miyatake, S; Yoshioka, M; Morris, J F; Butler, V P

1998-12-01

We have previously described the structures of four novel unconjugated bufadienolides in the ovary of the toad, Bufo marinus. In this study, we report the separation and characterization of three novel bufadienolide conjugates. These compounds were purified by HPLC, and their structures were determined to be 11alpha, 19-dihydroxytelocinobufagin-3-(12-hydroxydodecanoic acid) ester, 11alpha,19-dihydroxytelocinobufagin-3-(14-hydroxy-7-tetra decenoic acid) ester, and 11alpha, 19-dihydroxytelocinobufagin-3-(14-hydroxytetradecanoic acid) ester on the basis of NMR and MS data. Numerous dicarboxylic acid esters of bufadienolides have previously been described, but the three bufadienolide conjugates described in this report differ from previously described esters in that they contain hydroxylated monocarboxylic acids. The function of these three conjugates is not known but they are, like bufotoxins, potent inhibitors of Na+, K+-ATPase and may play a developmental role in the differentiation of toad oocytes.

Lusitania revisited: a phylogeographic analysis of the natterjack toad Bufo calamita across its entire biogeographical range.

PubMed

Rowe, Graham; Harris, D James; Beebee, Trevor J C

2006-05-01

Attempts to understand the current distributions of plants and animals require both historical and ecological information. Phylogeography has proved highly effective in elucidating historical events such as postglacial colonisations in north temperate zones. However, interesting questions still await resolution. Lusitanian distributions of fauna and flora in western Europe, for example, have puzzled biogeographers for more than 150 years. Lusitanian species have highly disjunct distributions in Ireland and in Iberia, often with few or no other populations inbetween. Despite much debate, no agreed explanation for Lusitanian distributions has yet emerged. We investigated the phylogeographic structure of one Lusitanian species, the natterjack toad Bufo calamita, using mitochondrial DNA control region sequences and allelic variation at eight microsatellite loci. Our results show that this amphibian must have survived in north European refugia, as well as in Iberia, during and since the last (Weichselian) glacial maximum around 20,000 years before present (BP). Subsequent local recolonisation after the Younger Dryas cooling around 11,000 years BP best explains the Lusitanian aspect of natterjack toad distribution.

Trypanosomes of Bufo americanus from northern Michigan.

PubMed

Werner, J K; Davis, J S; Slaght, K S

1988-10-01

Two hundred one American toads (Bufo americanus) from northern Michigan were examined for blood trypanosomes. Three species, Trypanosoma bufophlebotomi, T. schmidti-like sp. and T. pseudopodia, had prevalences of 27, 16 and 1%, respectively. Cross experimental inoculations showed that T. bufophlebotomi from toads is not the same as T. ranarum found in frogs of the family Ranidae of this region.

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

PubMed

Bernabò, Ilaria; Bonacci, Antonella; Coscarelli, Francesca; Tripepi, Manuela; Brunelli, Elvira

2013-05-15

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

The Ecological Genetics of Introduced Populations of the Giant Toad BUFO MARINUS. II. Effective Population Size

PubMed Central

Easteal, Simon

1985-01-01

The allele frequencies are described at ten polymorphic enzyme loci (of a total of 22 loci sampled) in 15 populations of the neotropical giant toad, Bufo marinus, introduced to Hawaii and Australia in the 1930s. The history of establishment of the ten populations is described and used as a framework for the analysis of allele frequency variances. The variances are used to determine the effective sizes of the populations. The estimates obtained (390 and 346) are reasonably precise, homogeneous between localities and much smaller than estimates of neighborhood size obtained previously using ecological methods. This discrepancy is discussed, and it is concluded that the estimates obtained here using genetic methods are the more reliable. PMID:3922852

Digitalis-like and vasoconstrictor effects of endogenous digoxin-like factor(s) from the venom of Bufo marinus toad.

PubMed

Bagrov, A Y; Roukoyatkina, N I; Fedorova, O V; Pinaev, A G; Ukhanova, M V

1993-04-06

Digitalis glycoside-like properties of the Bufo marinus toad crude venom and one of its constituents, bufalin, were studied in various assay systems. In concentrations 0.3-30 micrograms/ml crude venom increased the contractility of isolated electrically driven rat atria, constricted rat aortic rings, inhibited ouabain-sensitive Na+,K(+)-ATPase in rat erythrocytes and the Na+,K(+)-pump in rat aorta, and cross-reacted with antidigoxin antibody from the dissociation enhanced lanthanide fluoroimmunoassay (DELFIA). These effects were unaffected by adrenoceptor blockers and the 5-HT antagonist, deseril, but were blocked by antidigoxin antibody. Bufalin (10-30 microM) increased myocardial contractility and inhibited Na+,K(+)-ATPase in rat erythrocytes similarly to crude Bufo marinus venom. In rat aorta bufalin showed weak and delayed vasoconstrictor activity which was antagonized by 2 microM phentolamine, and had a biphasic effect on the Na+,K(+)-pump; 0.5-1.0 microM bufalin stimulated the pump, while higher concentrations inhibited its activity. Although the effects of bufalin were blocked by antidigoxin antibody, bufalin showed very low digoxin-like immunoreactivity in the DELFIA. These observations suggest that, in addition to bufalin, Bufo marinus venom contains at least one more digitalis-like steroid with significant intrinsic vasoconstrictor activity which, unlike bufalin, constricts the blood vessels acting directly via inhibition of the sodium pump in the vascular smooth muscle membrane.

Chronic toxicity of copper on embryo development in Chinese toad, Bufo gargarizans.

PubMed

Xia, Kun; Zhao, Hongfeng; Wu, Minyao; Wang, Hongyuan

2012-06-01

This study examined the effects of copper exposure on embryonic development of Chinese toad, Bufo gargarizans. Firstly, the LC(50) values from 24 to 96 h of exposure were 3.61×10(-6) M, by means of a 4 d toxicity test with B. gargarizans embryos. Secondly, Chinese toad embryos were exposed to 10(-9)-10(-6) M copper from mid gastrula stage to operculum completion stage. Measurements included mortality, tadpole weight, tadpole total length, growth retardation, duration of different embryo stages and malformation. Embryonic survival was not affected by copper. Relative to control tadpoles, significantly decreased weight and total length were found at 10(-9)-10(-6) M reduced percentage of the embryos in right operculum stage after 10 d exposure to copper and reduced percentage of embryos in operculum completion stage after 12 d exposure to copper were also observed. Moreover, the duration of embryonic development increased at neural, circulation and operculum development stage in copper-treated groups. For the scanning microscope and histological observation, the abnormalities were malformation of wavy dorsal fin, flexural tail, curvature body axis, yolk sac oedema and reduced pigmentation in the yolk sac. Histopathological changes in olfactory, retinal epithelium and skin were also observed. DNA strand breaks exposed to the copper were analyzed by DNA ladder. In conclusion, copper induced toxic effects on B. gargarizans embryos. The present study indicated chronic toxicity tests may provide more accurate way in formulating the "safe levels" of heavy metals to amphibian. Copyright © 2012 Elsevier Ltd. All rights reserved.

The effects of drought on population structure, activity, and orientation of toads Bufo quercicus and B. terrestris at a temporary pond

USGS Publications Warehouse

Dodd, C.K.

1994-01-01

From 1985 through 1990, I monitored the populations of two species of toads, Bufo quercicus and B. terrestris, at a temporary pond in the xeric uplands of north-central Florida. A drift fence with pitfall traps completely encircled the pond basin; the fence was monitored 5 days per week throughout the year. The 5-year study coincided with a severe regional drought that resulted in generally short hydroperiods at unpredictable times of the year. More than 800 toads were captured. Successful metamorphosis never occurred at the pond although toads continued to visit it throughout the study. The sex ratio was male biased in B. quercicus but not in B. terrestris, although significant variation was observed from one year to the next. Likewise, the size-class structure and length-weight patterns varied among species, sexes, and years. Although fewer toads entered the pond basin as the study progressed, toads may have gone elsewhere to breed or they may have remained in refugia. Thus, decreased capture does not necessarily indicate that a drought-related population decline occurred. Drought may have disrupted normal arrival patterns and length of stay within the pond basin. Drought also could be responsible for variation in annual size-class structure of captured toads. The uncertainty of the hydroperiod both spatially and temporally in adjacent breeding sites, the ability of toads to move long distances with the potential for migration between breeding sites, and the lack of specificity in the choice of breeding sites (i.e. permanent versus different types of temporary wetlands) may lead to the formation of metapopulations in the xeric upland habitats of north-central Florida. Long-term monitoring under a variety of climatic conditions is needed to assess the effects of drought and other types of environmental stresses on toad populations.

Ranking landscape development scenarios affecting natterjack toad (Bufo calamita) population dynamics in Central Poland.

PubMed

Franz, Kamila W; Romanowski, Jerzy; Johst, Karin; Grimm, Volker

2013-01-01

When data are limited it is difficult for conservation managers to assess alternative management scenarios and make decisions. The natterjack toad (Bufo calamita) is declining at the edges of its distribution range in Europe and little is known about its current distribution and abundance in Poland. Although different landscape management plans for central Poland exist, it is unclear to what extent they impact this species. Based on these plans, we investigated how four alternative landscape development scenarios would affect the total carrying capacity and population dynamics of the natterjack toad. To facilitate decision-making, we first ranked the scenarios according to their total carrying capacity. We used the software RAMAS GIS to determine the size and location of habitat patches in the landscape. The estimated carrying capacities were very similar for each scenario, and clear ranking was not possible. Only the reforestation scenario showed a marked loss in carrying capacity. We therefore simulated metapopulation dynamics with RAMAS taking into account dynamical processes such as reproduction and dispersal and ranked the scenarios according to the resulting species abundance. In this case, we could clearly rank the development scenarios. We identified road mortality of adults as a key process governing the dynamics and separating the different scenarios. The renaturalisation scenario clearly ranked highest due to its decreased road mortality. Taken together our results suggest that road infrastructure development might be much more important for natterjack toad conservation than changes in the amount of habitat in the semi-natural river valley. We gained these insights by considering both the resulting metapopulation structure and dynamics in the form of a PVA. We conclude that the consideration of dynamic processes in amphibian conservation management may be indispensable for ranking management scenarios.

Cane toads a threat to West Indian wildlife: mortality of Jamaican boas attributable to toad ingestion

Treesearch

Byron S. Wilson; Susan E. Koenig; Rick van Veen; Erika Miersma; D. Craig Rudolph

2011-01-01

The notorious ‘‘cane toad’’ (Bufo marinus) is considered to be one of the 100 worst invasive species in the world. A native of South and Central America, Mexico, and the Rio Grande Valley of the United States, this large toad was intentionally introduced to islands in the Caribbean, and subsequently throughout the southern Pacific, as a biological control agent to...

Salt adaptation in Bufo bufo

PubMed Central

Ferreira, H. G.; Jesus, C. H.

1973-01-01

1. The capacity of adaptation of toads (Bufo bufo) to environments of high salinity was studied and the relative importance of skin, kidney and urinary bladder in controlling the balance of water and salt was assessed. 2. Toads were kept in NaCl solutions of 20, 50, 110, 150 and 220 mM and studied in their fourth week of adaptation. A group of animals considered as `control' was kept in wet soil with free access to water. Plasma, ureter urine, and bladder and colon contents were analysed for sodium, potassium, chloride and osmolality, and total body sodium and water were determined. Absorption of water and 22Na through the skin, and water flow and sodium excretion through the ureter, of intact animals was studied. Hydrosmotic water transport through the isolated urinary bladder of `control' and adapted animals was determined. The effects of pitressin and aldosterone on the water and sodium balance are described. 3. The survival rates of toads kept in saline concentrations up to 150 mM were identical to that of `control' animals, but half of the animals kept in 220 mM died within 4 weeks. 4. There is a linear correlation between the sodium concentrations and osmolality of plasma and of the external media. 5. The sodium concentration in colon contents rose with rising external concentrations, up to values higher than the values in plasma. 6. Sodium concentrations and osmolalities of ureter and bladder urine increased in adapted animals, the values for bladder urine becoming much higher than those for ureter urine in animals adapted to 110, 150 and 220 mM. 7. Total body water, as a percentage of total weight was kept within very narrow limits, although the total body sodium increased with adaptation. 8. Absorption of water through the skin for the same osmotic gradients was smaller in adapted than in `control' animals. 9. The ureteral output of water of toads adapted to 110 and 150 mM-NaCl was larger than the water absorption through the skin. 10. Skin absorption of

Effect of lead acetate on the in vitro engulfment and killing capability of toad (Bufo arenarum) neutrophils.

PubMed

Rosenberg, Carolina E; Fink, Nilda E; Arrieta, Marcos A; Salibián, Alfredo

2003-11-01

Lead is an element of risk for the environment and human health and has harmful effects that may exceed those of other inorganic toxicants. The immune system is one of the targets of lead. Its immunomodulatory actions depend on the level of exposure, and it has been demonstrated that environmental amounts of the metal alter immune function. Very little information is available regarding the effect of the metal on different aspects of the immune system of lower vertebrates, in particular of amphibians. The aim of this study was to investigate the effect of sublethal lead (as acetate) on the function of polymorphonuclear cells of Bufo arenarum. The results revealed that phagocytic and lytic functions of the adherent blood cells collected from sublethal lead-injected toads and incubated with suspensions of Candida pseudotropicalis were affected negatively. The decrease of the phagocytic activity was correlated with increased blood lead levels (P < 0.0001). Additional information referred to the total and differential leukocyte counts was presented; the only difference found was in the number of blast-like cells that resulted augmented in the samples of lead-injected toads. It was concluded that the evaluation of these parameters might be a reliable tool for the biological monitoring of the immune status of amphibians.

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

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-09

... 4 through October 10, 2011, fire may be delayed or the endangered Houston toad (Bufo houstonensis... wild; or transported to the Houston toad captive breeding or captive assurance colony at the Houston...

Embryotoxicity of lead on Bufo arenarum

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

1988-08-01

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

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

DOE PAGES

Stark, Karolina; Scott, David E.; Tsyusko, Olga; ...

2015-04-30

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

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

Treesearch

David S. Pilliod; Erin Muths; Rick D. Scherer; Paul E. Bartelt; Paul Stephen Corn; Blake R. Hossack; Brad A. Lambert; Rebecca McCaffery; Christopher Gaughan

2010-01-01

Chytridiomycosis is linked to the worldwide decline of amphibians, yet little is known about the demographic effects of the disease. We collected capture-recapture data on three populations of boreal toads (Bufo boreas [Bufo = Anaxyrus]) in the Rocky Mountains (U.S.A.). Two of the populations were infected with chytridiomycosis and one was not. We examined the effect...

The effect of Zn2+ on glucose 6-phosphate dehydrogenase activity from Bufo arenarum toad ovary and alfalfa plants.

PubMed

Fonovich de Schroeder, Teresa M

2005-02-01

The effect of Zn2+ on glucose 6-phosphate dehydrogenase (G6PD) activity was monitored in samples from Bufo arenarum toad ovary and alfalfa plants, in the search for a possible new bioindicator able to detect levels of exposure through contaminated soils, and also to elucidate possible similarities between the enzyme from animal and plant tissues. The in vivo effect was evaluated after exposure of the toads to the metal in Ringer solution during 30 days and after 10 days of treatment in 6 weeks old plants, cultured under laboratory conditions. In vitro effects were measured in different extracts from control samples and partially purified enzyme from ovarian tissue as well as in different extracts from control alfalfa plants, by addition of the metal to the reaction mixture containing the enzyme. G6PD from toad ovary was noncompetitively inhibited by zinc both in vivo and in vitro, under all the experimental conditions studied. A kinetic analysis of the enzyme activity showed that the Michaelis-Menten constant (Km) was not modified, while maximal velocity (Vmax) decreased as the consequence of treatment. It was not possible to obtain a dose-response curve for the effects of Zn2+ on G6PD from alfalfa whole plants, measured in vivo or in vitro. Only leaf extracts evidenced a possible relationship between treatment with the metal and G6PD activity alteration. The results agree with a possible role for G6PD as a biomarker of effect and exposure to Zn2+ in B. arenarum ovarian tissue but not in alfalfa plants.

Fine-scale population structure in a desert amphibian: landscape genetics of the black toad (Bufo exsul).

PubMed

Wang, Ian J

2009-09-01

Environmental variables can strongly influence a variety of intra- and inter-population processes, including demography, population structure and gene flow. When environmental conditions are particularly harsh for a certain species, investigating these effects is important to understanding how populations persist under difficult conditions. Furthermore, species inhabiting challenging environments present excellent opportunities to examine the effects of complex landscapes on population processes because these effects will often be more pronounced. In this study, I use 16 microsatellite loci to examine population structure, gene flow and demographic history in the black toad, Bufo exsul, which has one of the most restricted natural ranges of any amphibian. Bufo exsul inhabits four springs in the Deep Springs Valley high desert basin and has never been observed more than several meters from any source of water. My results reveal limited gene flow and moderately high levels of population structure (F(ST) = 0.051-0.063) between all but the two closest springs. I found that the geographic distance across the arid scrub habitat between springs is significantly correlated with genetic structure when distance accounts for topography and barriers to dispersal. I also found very low effective population sizes (N(e) = 7-30) and substantial evidence for historical population bottlenecks in all four populations. Together, these results suggest that the desert landscape and B. exsul's high habitat specificity contribute significantly to population structure and demography in this species and emphasize the importance of considering behavioural and landscape data in conservation genetic studies of natural systems.

Surveys for California red-legged frog and arroyo toad on the Los Padres National Forest

Treesearch

Valerie K. Hubbartt; Thomas G. Murphey

2005-01-01

Starting in the spring of 1999 through the fall of 2000, USDA Forest Service biologists have conducted surveys throughout the Los Padres National Forest for the federally-listed California red-legged frog (Rana aurora draytonii) and arroyo toad (Bufo californicus). Sites known to have frogs or toads present were monitored for...

Effects of seasonal variation on oxidative stress physiology in natural population of toad Bufo melanostictus; clues for analysis of environmental pollution.

PubMed

Samanta, Luna; Paital, Biswaranjan

2016-11-01

Natural population of Bufo melanostictus in response to environmental cues shows several physiologic changes such as reproductive activity, hibernation, aestivation and metabolic depression in different seasons. We investigated the effects of seasonal fluctuations on oxidative stress (OS) physiology biomarkers, such as endogenous (ELPx) and induced (ILPx) lipid peroxidation, front-line redox regulatory enzymes (superoxide dismutase: SOD and catalase) and two non-enzyme antioxidant metabolites (ascorbic acid and reduced glutathione) in liver, gonad and cerebral hemisphere of toads collected from the Bhubaneswar area of India, where temperature fluctuates considerably rising to the highest in summer (∼46 °C) and being lowest in winter (<10 °C). Soil and air of the sampling site, although varying seasonally, were mostly found to be unpolluted, except for suspended particulate matter and respiratory particulate matter that were above recommended value. The magnitude of both ELPx and ILPx levels in most of the tissues, for example, ELPx in liver, cerebral hemisphere and ovary, and ILPx in liver of males and ovary, were found to be higher in rainy season in comparison to the other seasons. Nevertheless, levels of both ELPx and ILPx were low in testes in rainy season in comparison to the other two seasons. No correlation was observed between temperature and the studied OS parameters except a positive correlation with SOD and negative correlations with non-enzymatic small redox regulatory molecules in some selected tissues. Conversely, discriminant function analysis reveals a clear impact of the changing season on OS physiology of the toad. It implies that season considerably modulates OS physiology which be a reflection of the toads to abiotic pollutants alone and/or as results of metabolic changes under hibernation, aestivation and due to reproductive activities. Therefore, seasonal changes in OS physiological responses in poikilothermic models especially in toads

Phylogeography of Aegean green toads (Bufo viridis subgroup): continental hybrid swarm vs. insular diversification with discovery of a new island endemic.

PubMed

Dufresnes, Christophe; Lymberakis, Petros; Kornilios, Panagiotis; Savary, Romain; Perrin, Nicolas; Stöck, Matthias

2018-05-02

Debated aspects in speciation research concern the amount of gene flow between incipient species under secondary contact and the modes by which post-zygotic isolation accumulates. Secondary contact zones of allopatric lineages, involving varying levels of divergence, provide natural settings for comparative studies, for which the Aegean (Eastern Mediterranean) geography offers unique scenarios. In Palearctic green toads (Bufo viridis subgroup or Bufotes), Plio-Pleistocene (~ 2.6 Mya) diverged species show a sharp transition without contemporary gene flow, while younger lineages, diverged in the Lower-Pleistocene (~ 1.9 Mya), admix over tens of kilometers. Here, we conducted a fine-scale multilocus phylogeographic analysis of continental and insular green toads from the Aegean, where a third pair of taxa, involving Mid-Pleistocene diverged (~ 1.5 Mya) mitochondrial lineages, earlier tentatively named viridis and variabilis, (co-)occurs. We discovered a new lineage, endemic to Naxos (Central Cyclades), while coastal islands and Crete feature weak genetic differentiation from the continent. In continental Greece, both lineages, viridis and variabilis, form a hybrid swarm, involving massive mitochondrial and nuclear admixture over hundreds of kilometers, without obvious selection against hybrids. The genetic signatures of insular Aegean toads appear governed by bathymetry and Quaternary sea level changes, resulting in long-term isolation (Central Cyclades: Naxos) and recent land-bridges (coastal islands). Conversely, Crete has been isolated since the end of the Messinian salinity crisis (5.3 My) and Cretan populations thus likely result from human-mediated colonization, at least since Antiquity, from Peloponnese and Anatolia. Comparisons of green toad hybrid zones support the idea that post-zygotic hybrid incompatibilities accumulate gradually over the genome. In this radiation, only one million years of divergence separate a scenario of complete reproductive

Differing long term trends for two common amphibian species (Bufo bufo and Rana temporaria) in alpine landscapes of Salzburg, Austria

PubMed Central

Kyek, Martin; Lindner, Robert

2017-01-01

This study focuses on the population trends of two widespread European anuran species: the common toad (Bufo bufo) and the common frog (Rana temporaria). The basis of this study is data gathered over two decades of amphibian fencing alongside roads in the Austrian state of Salzburg. Different statistical approaches were used to analyse the data. Overall average increase or decrease of each species was estimated by calculating a simple average locality index. In addition the statistical software TRIM was used to verify these trends as well as to categorize the data based on the geographic location of each migration site. The results show differing overall trends for the two species: the common toad being stable and the common frog showing a substantial decline over the last two decades. Further analyses based on geographic categorization reveal the strongest decrease in the alpine range of the species. Drainage and agricultural intensification are still ongoing problems within alpine areas, not only in Salzburg. Particularly in respect to micro-climate and the availability of spawning places these changes appear to have a greater impact on the habitats of the common frog than the common toad. Therefore we consider habitat destruction to be the main potential reason behind this dramatic decline. We also conclude that the substantial loss of biomass of a widespread species such as the common frog must have a severe, and often overlooked, ecological impact. PMID:29121054

Synthetic rainfall vibrations evoke toad emergence.

PubMed

Márquez, Rafael; Beltrán, Juan F; Llusia, Diego; Penna, Mario; Narins, Peter M

2016-12-19

Toads occupy underground refugia during periods of daily or seasonal inactivity, emerging only during rainfall [1]. We test the hypothesis that rainfall-induced vibrations in soil are the cues that trigger the emergence of toads from underground. Using playback experiments in the absence of natural rainfall in native habitats, we observed that two Iberian toad species (Pelobates cultripes and Bufo calamita) emerged significantly earlier than controls when exposed to low-frequency soil vibrations that closely mimic those of rainfall. Our results suggest that detection of abiotic seismic events are biologically relevant and widespread in arid-zone anurans. These findings provide insights into the evolutionary role played by the two low-frequency-tuned inner-ear organs in anuran amphibians - the amphibian papilla and sacculus, both detectors of weak environmental vibrational cues. Copyright © 2016 Elsevier Ltd. All rights reserved.

DIET OF THE SOUTHERN TOAD FROM THE SOUTHERN EVERGLADES

EPA Science Inventory

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

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

USGS Publications Warehouse

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

2010-01-01

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

Distribution and pathogenicity of Batrachochytrium dendrobatidis in boreal toads from the Grand Teton area of western Wyoming

Treesearch

Peter J. Murphy; Sophie St-Hilaire; Sarah Bruer; Paul Stephen Corn; Charles R. Peterson

2009-01-01

The pathogen Batrachochytrium dendrobatidis (Bd), which causes the skin disease chytridiomycosis, has been linked to amphibian population declines and extinctions worldwide. Bd has been implicated in recent declines of boreal toads, Bufo boreas boreas, in Colorado but populations of boreal toads in western Wyoming have high prevalence of Bd without suffering...

Characterization of urea transport in Bufo arenarum oocytes.

PubMed

Silberstein, Claudia; Zotta, Elsa; Ripoche, Pierre; Ibarra, Cristina

2003-07-01

Xenopus laevis oocytes have been extensively used for expression cloning, structure/function relationships, and regulation analysis of transporter proteins. Urea transporters have been expressed in Xenopus oocytes and their properties have been described. In order to establish an alternative system in which urea transporters could be efficiently expressed and studied, we determined the urea transport properties of ovarian oocytes from Bufo arenarum, a toad species common in Argentina. Bufo oocytes presented a high urea permeability of 22.3 x 10(-6) cm/s, which was significantly inhibited by the incubation with phloretin. The urea uptake in these oocytes was also inhibited by mercurial reagents, and high-affinity urea analogues. The urea uptake was not sodium dependent. The activation energy was 3.2 Kcal/mol, suggesting that urea movement across membrane oocytes may be through a facilitated urea transporter. In contrast, Bufo oocytes showed a low permeability for mannitol and glycerol. From these results, we propose that one or several specific urea transporters are present in ovarian oocytes from Bufo arenarum. Therefore, these oocytes cannot be used in expression studies of foreign urea transporters. The importance of Bufo urea transporter is not known but could be implicated in osmotic regulation during the laying of eggs in water. Copyright 2003 Wiley-Liss, Inc.

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

PubMed

Salazar, Rosie D; Montgomery, Robert A; Thresher, Sarah E; Macdonald, David W

2016-01-01

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

AN ELECTRON MICROSCOPE STUDY OF SPERMATID DIFFERENTIATION IN THE TOAD, BUFO ARENARUM HENSEL

PubMed Central

Burgos, Mario H.; Fawcett, Don W.

1956-01-01

The differentiation of the spermatids of Bufo arenarum has been described from a study of electron micrographs of thin sections of testis. The development of the acrosome from the Golgi complex takes place in much the same manner as in mammalian spermatogenesis but no acrosome granule is formed. A perforatorium is described for the first time in this species. It is formed by a convergence of dense filaments that arise between the nuclear membrane and the head cap. During maturation of the spermatid the chromatin undergoes striking physicochemical alterations. Fine chromatin granules uniformly dispersed in the karyoplasm are replaced by larger and larger aggregates and these ultimately coalesce to form a very dense sperm head. Two centrioles of cylindrical form are situated very near the base of the sperm head. The longitudinal fibrils of the tail flagellum take origin from one, and the dense fibrous substance of the undulating membrane is closely related to the other. Phase contrast cinematographic observations on the swimming movements of living toad sperm, when considered in relation to the fine structural components of the tail, suggest that there is a contractile component in the undulating membrane as well as in the axial fibrils. The differences in the structure of mammalian and amphibian sperm tails are discussed in relation to differences in the character of their movements. PMID:13331956

Museum material reveals a frog parasite emergence after the invasion of the cane toad in Australia

PubMed Central

2010-01-01

Background A parasite morphologically indistinguishable from Myxidium immersum (Myxozoa: Myxosporea) found in gallbladders of the invasive cane toad (Bufo marinus) was identified in Australian frogs. Because no written record exists for such a parasite in Australian endemic frogs in 19th and early 20th century, it was assumed that the cane toad introduced this parasite. While we cannot go back in time ourselves, we investigated whether material at the museum of natural history could be used to retrieve parasites, and whether they were infected at the time of their collection (specifically prior to and after the cane toad translocation to Australia in 1935). Results Using the herpetological collection at the Australian Museum we showed that no myxospores were found in any animals (n = 115) prior to the cane toad invasion (1879-1935). The green and golden bell frog (Litoria aurea), the Peron's tree frog (Litoria peronii), the green tree frog (Litoria caerulea) and the striped marsh frog (Limnodynastes peronii) were all negative for the presence of the parasite using microscopy of the gallbladder content and its histology. These results were sufficient to conclude that the population was free from this disease (at the expected minimum prevalence of 5%) at 99.7% confidence level using the 115 voucher specimens in the Australian Museum. Similarly, museum specimens (n = 29) of the green and golden bell frog from New Caledonia, where it was introduced in 19th century, did not show the presence of myxospores. The earliest specimen positive for myxospores in a gallbladder was a green tree frog from 1966. Myxospores were found in eight (7.1%, n = 112) frogs in the post cane toad introduction period. Conclusion Australian wildlife is increasingly under threat, and amphibian decline is one of the most dramatic examples. The museum material proved essential to directly support the evidence of parasite emergence in Australian native frogs. This parasite can be considered one of

Evidence toads may modulate landing preparation without predicting impact time

PubMed Central

Cox, S. M.; Gillis, Gary

2017-01-01

ABSTRACT Within anurans (frogs and toads), cane toads (Bufo marinus) perform particularly controlled landings in which the forelimbs are exclusively used to decelerate and stabilize the body after impact. Here we explore how toads achieve dynamic stability across a wide range of landing conditions. Specifically, we suggest that torques during landing could be reduced by aligning forelimbs with the body's instantaneous velocity vector at impact (impact angle). To test whether toad forelimb orientation varies with landing conditions, we used high-speed video to collect forelimb and body kinematic data from six animals hopping off platforms of different heights (0, 5 and 9 cm). We found that toads do align forelimbs with the impact angle. Further, toads align forelimbs with the instantaneous velocity vector well before landing and then track its changes until touchdown. This suggests that toads may be prepared to land well before they hit the ground rather than preparing for impact at a specific moment, and that they may use a motor control strategy that allows them to perform controlled landings without the need to predict impact time. PMID:27895052

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

USGS Publications Warehouse

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

2007-01-01

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

Effects of Petrol Exposure on Glucose, Liver and Muscle glycogen levels in the Common African toad Bufo regularis.

PubMed

Isehunwa, G O; Yusuf, I O; Alada, A Ar

2017-03-06

This study investigated the effects of exposure to petrol on blood glucose, liver and muscle glycogen levels in the common African toad Bufo regularis. A total of 126 adult toads of either sex weighing between 70-100g were used for this study. The experiment was divided into three phases. The phase 1 experiment the acute toxicity test consisted of animals divided into six groups of 10 toads per group and were exposed to water (H2O), H2O + Tween 80, 2ml/l, 3ml/l, 5ml/l, and 10ml/l of petrol respectively for 96 hours using the static renewal bioassay system. In the Phase 2 experiment, the animals were exposed to H2O, H2O + Tween 80, 0.14ml/l, 0.3ml/l, 0.6ml/l, and 1.13ml/l of petrol respectively for 3 days; while in phase 3 experiment they were exposed to petrol solutions for 14 days. After the various exposures, the blood glucose, liver and muscle glycogen contents were determined using standard methods. The results of the study showed that the median lethal concentration of petrol (96 hours LC50) was 4.5ml/l and sub-lethal concentration of petrol caused mortality of animals. Exposure to petrol solutions for 3 days had no significant effect on blood glucose level of the animals but caused significant decrease in the liver and muscle glycogen levels at high concentrations. In the animals exposed to petrol solutions for 14 days, there was a significant increase in glucose levels and significant reduction in liver and muscle glycogen levels at high concentrations when compared with the control. The results show that sub-lethal concentrations of petrol can cause mortality of animals, hyperglycemia and reduction in liver and muscle glycogen levels. The effects of petrol exposure on carbohydrate metabolism depend on the concentration and duration of exposure.

A Suspected Parasite Spill-Back of Two Novel Myxidium spp. (Myxosporea) Causing Disease in Australian Endemic Frogs Found in the Invasive Cane Toad

PubMed Central

Hartigan, Ashlie; Fiala, Ivan; Dyková, Iva; Jirků, Miloslav; Okimoto, Ben; Rose, Karrie; Phalen, David N.; Šlapeta, Jan

2011-01-01

Infectious diseases are contributing to the decline of endangered amphibians. We identified myxosporean parasites, Myxidium spp. (Myxosporea: Myxozoa), in the brain and liver of declining native frogs, the Green and Golden Bell frog (Litoria aurea) and the Southern Bell frog (Litoria raniformis). We unequivocally identified two Myxidium spp. (both generalist) affecting Australian native frogs and the invasive Cane toad (Bufo marinus, syn. Rhinella marina) and demonstrated their association with disease. Our study tested the identity of Myxidium spp. within native frogs and the invasive Cane toad (brought to Australia in 1935, via Hawaii) to resolve the question whether the Cane toad introduced them to Australia. We showed that the Australian brain and liver Myxidium spp. differed 9%, 7%, 34% and 37% at the small subunit rDNA, large subunit rDNA, internal transcribed spacers 1 and 2, but were distinct from Myxidium cf. immersum from Cane toads in Brazil. Plotting minimum within-group distance against maximum intra-group distance confirmed their independent evolutionary trajectory. Transmission electron microscopy revealed that the brain stages localize inside axons. Myxospores were morphologically indistinguishable, therefore genetic characterisation was necessary to recognise these cryptic species. It is unlikely that the Cane toad brought the myxosporean parasites to Australia, because the parasites were not found in 261 Hawaiian Cane toads. Instead, these data support the enemy-release hypothesis predicting that not all parasites are translocated with their hosts and suggest that the Cane toad may have played an important spill-back role in their emergence and facilitated their dissemination. This work emphasizes the importance of accurate species identification of pathogens relevant to wildlife management and disease control. In our case it is paving the road for the spill-back role of the Cane toad and the parasite emergence. PMID:21541340

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

Treesearch

Christina T. Liang; Thomas J. Stohlgren

2011-01-01

Understanding patch variability is crucial in understanding the spatial population structure of wildlife species, especially for rare or threatened species.We used a well-tested maximum entropy species distribution model (Maxent) to map the Yosemite toad (Anaxyrus (= Bufo) canorus) in the Sierra Nevada...

Brown skin disease: A syndrome of dysecdysis in Puerto Rican crested toads (Peltophryne lemur).

PubMed

Crawshaw, Graham; Pienkowski, Maria; Lentini, Andrew; Dutton, Christopher; Delnatte, Pauline; Russell, Deanna; Berkvens, Charlene; Barker, Ian; Smith, Dale

2014-01-01

The endangered Puerto Rican crested toad (Peltophryne [Bufo] lemur) has been held and bred in zoos for release into protected areas in Puerto Rico since 1982. In 2004, several cases of a novel syndrome of skin changes in toads were noticed at the Toronto Zoo. A total of 21 toads were found to have similar lesions and the condition has been seen in several other groups of toads in subsequent years. Affected toads show an uncharacteristic sheen of dark-brown leathery skin, followed by recurring dysecdysis, reduced appetite, weight loss, and death from secondary causes. Histologically the condition is characterized by epithelial hyperplasia and hyperkeratosis, ulceration, and the presence of superficial mats of bacterial and fungal agents. No etiology has been identified and to date toads have not permanently responded to treatment with various pharmaceutical and nutritional therapies. © 2014 Wiley Periodicals, Inc.

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

PubMed

Baier, Fabian; Gruber, Edith; Hein, Thomas; Bondar-Kunze, Elisabeth; Ivanković, Marina; Mentler, Axel; Brühl, Carsten A; Spangl, Bernhard; Zaller, Johann G

2016-01-01

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

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

PubMed Central

Baier, Fabian; Gruber, Edith; Bondar-Kunze, Elisabeth; Ivanković, Marina; Mentler, Axel; Brühl, Carsten A.; Spangl, Bernhard

2016-01-01

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

The effect of soil composition and hydration on the bioavailability and toxicity of cadmium to hibernating juvenile American toads (Bufo americanus)

USGS Publications Warehouse

James, Stacy M.; Little, Edward E.; Semlitsch, Raymond D.

2004-01-01

The soil ecotoxicology literature has focused primarily on a few major taxa, to the neglect of other fossorial organisms such as amphibians. We selected cadmium (Cd) and the American toad (Bufo americanus) as a model contaminant and biological species to assess the impact of soil contamination on amphibian hibernation survival and post-hibernation condition. Soil sand composition (50, 70, 90%) and hydration (100, 150% water holding capacity (WHC)) were manipulated in addition to Cd concentration (0, 56, 165, 483 μg/g) to determine whether these soil properties affect toxicity. Soil Cd concentration significantly reduced survival and locomotor performance, and was correlated negatively with percent mass loss and positively with whole body Cd concentration. Higher sand content resulted in less mass loss and greater Cd uptake. Toads that were hibernated in 50% sand hydrated to 100% WHC had higher survival, less mass loss, and better sprint performance than those hibernated in 50% sand, 150% WHC. This study demonstrates that concentrations of Cd found in soil at highly contaminated sites can be bioaccumulated by hibernating amphibians and may reduce fitness. Differences in microhabitat use may cause species to vary in their exposure and susceptibility to soil contamination. The toxicity of Cd to amphibians could be greater in natural systems where there are multiple stressors and fluctuations in environmental variables.

76 FR 7245 - Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for the Arroyo Toad

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-09

...We, the U.S. Fish and Wildlife Service (Service), are designating final revised critical habitat for the arroyo toad (Anaxyrus californicus, Bufo californicus). We are designating approximately 98,366 acres (ac) (39,807 hectares (ha)) of habitat in Santa Barbara, Ventura, Los Angeles, San Bernardino, Riverside, Orange, and San Diego Counties, California, as critical habitat for the arroyo toad. This final revised designation constitutes an increase of approximately 86,671 ac (35,074 ha) from the 2005 designation of critical habitat for the arroyo toad. A taxonomic name change has occurred and been accepted for the arroyo toad. Throughout the remainder of this document we will use the currently recognized name for the listed entity, Anaxyrus californicus, for references to the arroyo toad.

In vitro hCG and human recombinant FSH actions on testicular steroidogenesis in the toad Bufo arenarum.

PubMed

Canosa, L F; Ceballos, N R

2002-05-01

In order to study the regulation of testicular steroidogenesis in the toad Bufo arenarum, the effect of gonadotropins (hCG and hrFSH) on steroidogenic enzymes was determined using an in vitro system. 3beta-Hydroxysteroid dehydrogenase/isomerase activity was not affected by any of the gonadotropins, at any of the concentrations used. In contrast, 5alpha-reductase activity was strongly reduced by both hCG and hrFSH. Human chorionic gonadotropin inhibited the activity of cytochrome P450 17alpha-hydroxylase-C(17-20) lyase (P450(c17)), only at the highest concentration used, while hrFSH strongly reduced P450(c17) activity at all the doses assayed. In conclusion, these data suggest that LH (hCG) and FSH regulate steroidogenic enzymes such as 5alphaRed and P450(c17). The results also suggest that FSH could be involved in the regulation of the change in steroidogenesis undergone by the testis during the breeding season. In turn, the inhibition of P450(c17) activity could result in a reduction of androgen production and an increment of C21 steroids. (c) 2002 Elsevier Science (USA).

Role of environmental pollutants on immune functions, parasitic infections and limb malformations in marine toads and whistling frogs from Bermuda.

PubMed

Linzey, Donald; Burroughs, Joy; Hudson, Lisa; Marini, Michele; Robertson, John; Bacon, Jamie; Nagarkatti, Mitzi; Nagarkatti, Prakash

2003-06-01

Soil, water, and amphibian tissues collected between 1995 and 1999 from 15 study sites in Bermuda were analysed for pesticides and heavy metals. The most abundant pesticide residue in soil was p,p'-dichlorodiphenyldichloroethylene (DDE) which was found at all sites in concentrations ranging from 0.003 to 4.023 p.p.m. No pesticide residues were found in water. DDE was also recovered from the livers and fat bodies of marine toads (Bufo marinus) and whistling frogs (Eleutherodactylus johnstonei). Analyses of food sources consumed by these anuran species revealed residue levels of p, p'-DDE ranging from 0.05 to 0.217 p.p.m. Other soil residues included dichlorodiphenyltrichloroethane (DDT) at eight study sites, Dicofol(kelthane) at eight sites, dieldrin at five sites, and polychlorinated biphenyls (PCBs) as Arochlor 1254 and Arochlor 1260 at seven sites. Analyses of toad livers revealed significant concentrations of cadmium, chromium, copper and zinc. Livers of Bermuda toads exhibited altered hepatocytic morphology and an increased number of melanomacrophages and possible granulomas, while spleens showed a marked decrease in white pulp. Spleen cells from Bufo marinus collected at one site having high levels of cadmium exhibited a decreased B cell response to lipopolysaccharide. The incidence of trematode infection in Bufo marinus increased from 53.8% in 1995 to 90% in 1999. Deformity rates in the limbs of subadult and adult toads ranged between 15 and 25%. Examination of 1,995 newly-metamorphosed toads revealed deformity rates as high as 47%. The current comprehensive study suggests that environmental pollutants may account for immunosuppression, increased susceptibility to infections, limb malformations and possible decline in amphibian populations from Bermuda.

Development of Trypanosoma fallisi in the leech, Desserobdella picta, in toads (Bufo americanus), and in vitro. A light and electron microscopic study.

PubMed

Martin, D S; Desser, S S

1991-01-01

The development of Trypanosoma fallisi of Bufo americanus from Algonquin Park, Ontario was studied by light and electron microscopy in blood culture, in its leech vector Desserobdella (= Batracobdella) picta, and in its toad host. In culture, bloodstream trypomastigotes transformed within one day to elongate epimastigotes which divided into rosettes. These gave rise to amastigotes, spheromastigotes, stumpy and elongate epimastigotes, and slender metacyclic trypomastigotes over a 4- to 6-day period. Development in the leech crop was similar to that in culture, with fewer amastigotes and no spheromastigotes observed. The stages in the leech were similar in size to their culture counterparts, except for metacyclic trypomastigotes, which were larger in culture. Culture and leech stages possessed a well developed cytostome-cytopharyngeal complex and prominent reservosomes. The kinetoplast of crop stages was small with a rectangular profile, but became larger and basket-like in the proboscis forms. Migration of trypanosomes to the proboscis appeared to depend on the rate of digestion of the bloodmeal. Flagellates in the leech were also characterized by the presence of intracellular microorganisms. Development of culture forms to mature stages in the toad was completed within 8 days postinoculation, with the organisms transforming into the typical "C"-shape with a large square kinetoplast. Natural infection of B. americanus was detected at 3 days postfeeding by D. picta and the resulting bloodstream trypomastigotes developed more slowly than inoculated cultured stages.

WHEN A PHYLOGENETIC TRICHOTOMY MAKES SENSES: PHYLOGEOGRAPHY OF BUFO PUNCTATUS AND THE EVOLUTION OF THE WARM DESERTS

EPA Science Inventory

Bufo punctatus, the red-spotted toad, is a common, desert-adapted anuran with a widespread distribution throughout warm, and regions of North America. This distribution makes this species ideal for evaluating alternative scenarios of biotic response to geotectonically and climat...

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

USGS Publications Warehouse

2001-01-01

The Wyoming toad was listed as an endangered species under the Endangered Species Act on January 17, 1984, with a recovery plan approved in 1991. Currently the total population of the Wyoming toad includes approximately 200 animals in the captive breeding program and as few as 62 toads surviving at reintroduction sites in the Laramie Basin based upon fall 2000 survey data (after releases of more than 10,000 toads and tadpoles since 1995). Necessary conservation measures include improving reproduction and survival in the captive breeding program, improving survival at reintroduction sites, developing techniques to control the effects of the amphibian chytrid fungus, and eliminating threats and further habitat degradation in the wild.

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

PubMed Central

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

2016-01-01

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

PHYLOGEOGRAPHY OF BUFO PUNCTATUS: LONG TERM EVOLUTION WITHIN THE WARM DESERTS OF NORTH AMERICA AND LATE QUATERNARY RANGE SHIFTING

EPA Science Inventory

Bufo punctatus, the red-spotted toad, is a widespread anuran of the warm-desert regions of western North America. This distribution makes this species ideal for evaluating biotic response to geotectonically and climatically mediated episodes of landscape transformation (e.g., ear...

Tachykinin receptors in the small intestine of the cane toad (Bufo marinus): a radioligand binding and functional study.

PubMed

Burcher, E; Warner, F J

1998-06-01

In this study, we have used radioligand binding and functional techniques to investigate tachykinin receptors in the small intestine of the cane toad Bufo marinus. The radioligand [125I]Bolton-Hunter [Sar9,Met(O2)11]substance P (selective at mammalian NK-1 receptors) showed no specific binding. Specific binding of [125I]Bolton-Hunter substance P ([125I]BHSP) was saturable, of high affinity (Kd 0.3 nM) and was inhibited by SP (IC50 0.64 nM) > ranakinin approximately neurokinin A (NKA) > or = SP(5-11) > or = neuropeptide gamma > or = scyliorhinin II > scyliorhinin I > or = [Sar9]-SP > or = neurokinin B approximately physalaemin approximately carassin > SP(7-11) approximately eledoisin > or = SP(4-11) approximately SP(6-11). Binding was also inhibited by Gpp[NH]p > or = GTPgammaS > App[NH]p, indicating a G-protein coupled receptor. The order of potency of tachykinins and analogues in contracting the isolated lower small intestine was carassin (EC50 1.4 nM) > eledoisin approximately SP > or = physalaemin > or = ranakinin > SP(6-11) > scyliorhinin II > or = neuropeptide gamma > neurokinin B approximately NKA approximately scyliorhinin I > or = SP(4-11) > or = SP(5-11) > [Sar9]SP > SP(7-11). In both studies, the selective mammalian NK-1, NK-2 and NK-3 receptor agonists [Sar9,Met(O2)11]SP, [Lys5,Me-Leu9,Nle10]NKA(4-10) and senktide were weak or ineffective. There was a strong positive correlation between the pD2 and pIC50 values for mammalian tachykinins and analogues (r = 0.907), but not for the non-mammalian tachykinins, which were all full agonists but variable binding competitors. [Sar9,Met(O2)11]-SP(pD2 5.7) was approximately 25-fold less potent as an agonist than [Sar9]SP, which was itself 25-fold weaker than SP. Responses to SP were significantly reduced (n = 8, P<0.001) by the antagonist [D-Arg1,D-Trp7,9,Leu11]-SP (spantide; 1 microM). Highly selective NK-1 receptor antagonists including CP 99994 and GR 82334 (both 1 microM) were ineffective in both functional and

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

Treesearch

Cathryn H. Greenberg; George W. Tanner

2005-01-01

We used data from 10 years of continuous, concurrent monitoring of oak toads at eight isolated, ephemeral ponds in Florida longleaf pine-wiregrass uplands to address: (1): did weather variables affect movement patterns of oak toads? (2) did pond hydrology and the condition of surrounding uplands affect pond selection by adults or juvenile recruitment? (3) were...

LOCAL SCALE FACTORS DETERMINE HABITAT PATCH OCCUPANCY BY RED-SPOTTED TOADS IN A NATURALLY FRAGMENTED DESERT LANDSCAPE

EPA Science Inventory

Amphibians are often thought to have a metapopulation structure, which may render them vulnerable to habitat fragmentation. The red-spotted toad (Bufo punctatus) in the southwestern USA and Mexico commonly inhabits wetlands that have become much smaller and fewer since the late P...

Curcumin synergizes the growth inhibitory properties of Indian toad (Bufo melanostictus Schneider) skin-derived factor (BM-ANF1) in HCT-116 colon cancer cells.

PubMed

Giri, Biplab; Gomes, Antony; Sengupta, Radha; Banerjee, Sanjeev; Nautiyal, Jyoti; Sarkar, Fazlul H; Majumdar, Adhip P N

2009-01-01

Curcumin, an active ingredient of turmeric with no discernable toxicity, inhibits the growth of transformed cells and the development and progression of colon carcinogenesis in experimental animals. Recent data from one of our laboratories demonstrated that a crude skin extract or a purified crystalline compound (Bufo melanostictus-antineoplastic factor 1, BM-ANF1) from Indian common toad (Bufo melanostictus, Schneider) skin inhibits the growth of human leukemic cells. The present investigation was undertaken to determine whether combining BM-ANF1 with curcumin would be a better therapeutic strategy for colon cancer. Colon cancer HCT-116 cells were used. Changes in growth, apoptosis, growth factor receptor signaling and events of the cell cycle were analyzed. Curcumin together with BM-ANF1 produced a greater inhibition of HCT-116 cells growth than either agent alone, attributable to the inhibition of proliferation and stimulation of apoptosis, as evidenced by suppression of proliferating cell nuclear antigen (PCNA) expression, cell cycle arrest at the G2/M-phase and caspase-3 activation. There was also a marked reduction of cyclin-dependent kinase (CDK)2, CDK4 and cyclin B expression and up-regulation of CDK inhibitors (p21, p27) and p53, accompanied by attenuation of Akt signaling and nuclear factor-kappa B (NF-kappaB) activation. BM-ANF1 in combination with curcumin causes a marked inhibition of growth of colon cancer cells and could be an effective therapeutic strategy for colon cancer.

Effective number of breeding adults in Bufo bufo estimated from age-specific variation at minisatellite loci

USGS Publications Warehouse

Scribner, K.T.; Arntzen, J.W.; Burke, T.

1997-01-01

Estimates of the effective number of breeding adults were derived for three semi-isolated populations of the common toad Bufo bufo based on temporal (i.e. adult-progeny) variance in allele frequency for three highly polymorphic minisatellite loci. Estimates of spatial variance in allele frequency among populations and of age-specific measures of genetic variability are also described. Each population was characterized by a low effective adult breeding number (N(b)) based on a large age-specific variance in minisatellite allele frequency. Estimates of N(b) (range 21-46 for population means across three loci) were ??? 55-230-fold lower than estimates of total adult census size. The implications of low effective breeding numbers for long-term maintenance of genetic variability and population viability are discussed relative to the species' reproductive ecology, current land-use practices, and present and historical habitat modification and loss. The utility of indirect measures of population parameters such as N(b) and N(e) based on time-series data of minisatellite allele frequencies is discussed relative to similar measures estimated from commonly used genetic markers such as protein allozymes.

Hormonal induction of spermatozoa from amphibians with Rana temporaria and Bufo bufo as anuran models.

PubMed

Uteshev, V K; Shishova, N V; Kaurova, S A; Browne, R K; Gakhova, E N

2012-01-01

The use of hormonally induced spermatozoa expressed in urine (HISu) is a valuable component of reproduction technologies for amphibians. Five protocols for sampling HISu from the European common frog (Rana temporaria) were compared: (1) pituitary extracts, (2) 0.12 µg g⁻¹ luteinising hormone-releasing hormone analogue (LHRHa), (3) 1.20 µg g⁻¹ LHRHa, (4) 11.7 IU g⁻¹ human chorionic gonadotrophin (hCG) and (5) 23.4 IU g⁻¹ hCG (g⁻¹ = per gram bodyweight). From 1 to 24h after administration we assessed the number and concentration of spermatozoa in spermic urine and in holding water, and in urine the percentage of motile spermatozoa and their progressive motility. The protocol using 1.20 µg g⁻¹ LHRHa gave the highest total sperm numbers (650 × 10⁶) and the highest percentage (40%) of samples with sperm concentrations above 200 × 10⁶ mL⁻¹. The percentage motility and progressive motility was similar from all protocols. Considerable amounts of spermatozoa were expressed by R. temporaria into their holding water. We tested hormonal priming and spermiation in the common toad (Bufo bufo) using 0.13 µg g⁻¹ LHRHa administered 24h before a final spermiating dose of 12.8 IU g⁻¹ hCG. No spermatozoa were expressed in holding water. Priming resulted in 35% more spermatozoa than without; however, there were no differences in sperm concentrations. Primed B. bufo produced spermatozoa with significantly higher percentage motility, but not progressive motility, membrane integrity, or abnormal spermatozoa than unprimed males.

Serum protein profile and blood cell counts in adult toads Bufo arenarum(Amphibia: Anura: Bufonidae): effects of sublethal lead acetate.

PubMed

Chiesa, María E; Rosenberg, Carolina E; Fink, Nilda E; Salibián, Alfredo

2006-04-01

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

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

USGS Publications Warehouse

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

2000-01-01

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

Corticosteroidogenesis in the toad Bufo arenarum H: evidence for a precursor role for an aldosterone 3 beta-hydroxy-5-ene analogue (3 beta, 11 beta, 21-trihydroxy-20-oxo-5-pregnen-18-al).

PubMed Central

Ceballos, N R; Shackleton, C H; Harnik, M; Cozza, E N; Gros, E G; Lantos, C P

1993-01-01

A material isolated following pregnenolone incubations with toad (Bufo arenarum) inter-renal tissue at 28 degrees C has been identified as a 3 beta-hydroxy-5-ene analogue of aldosterone (3 beta, 11 beta, 21-trihydroxy-20-oxo-5-pregnen-18-al). The initial identification was made by enzymic and m.s. methods, and structural confirmation was achieved through comparison with chemically synthesized authentic material. The relative efficacy of corticosterone, 18-hydroxycorticosterone and the 3 beta-hydroxy-5-ene aldosterone analogue as aldosterone precursors was evaluated. In the in vitro situation studied, the 3 beta-hydroxy-5-ene steroid was by far the best precursor. PMID:8503841

Corticosteroidogenesis in the toad Bufo arenarum H: evidence for a precursor role for an aldosterone 3 beta-hydroxy-5-ene analogue (3 beta, 11 beta, 21-trihydroxy-20-oxo-5-pregnen-18-al).

PubMed

Ceballos, N R; Shackleton, C H; Harnik, M; Cozza, E N; Gros, E G; Lantos, C P

1993-05-15

A material isolated following pregnenolone incubations with toad (Bufo arenarum) inter-renal tissue at 28 degrees C has been identified as a 3 beta-hydroxy-5-ene analogue of aldosterone (3 beta, 11 beta, 21-trihydroxy-20-oxo-5-pregnen-18-al). The initial identification was made by enzymic and m.s. methods, and structural confirmation was achieved through comparison with chemically synthesized authentic material. The relative efficacy of corticosterone, 18-hydroxycorticosterone and the 3 beta-hydroxy-5-ene aldosterone analogue as aldosterone precursors was evaluated. In the in vitro situation studied, the 3 beta-hydroxy-5-ene steroid was by far the best precursor.

Effects of an invasive plant on population dynamics in toads.

PubMed

Greenberg, Daniel A; Green, David M

2013-10-01

When populations decline in response to unfavorable environmental change, the dynamics of their population growth shift. In populations that normally exhibit high levels of variation in recruitment and abundance, as do many amphibians, declines may be difficult to identify from natural fluctuations in abundance. However, the onset of declines may be evident from changes in population growth rate in sufficiently long time series of population data. With data from 23 years of study of a population of Fowler's toad (Anaxyrus [ = Bufo] fowleri) at Long Point, Ontario (1989-2011), we sought to identify such a shift in dynamics. We tested for trends in abundance to detect a change point in population dynamics and then tested among competing population models to identify associated intrinsic and extrinsic factors. The most informative models of population growth included terms for toad abundance and the extent of an invasive marsh plant, the common reed (Phragmites australis), throughout the toads' marshland breeding areas. Our results showed density-dependent growth in the toad population from 1989 through 2002. After 2002, however, we found progressive population decline in the toads associated with the spread of common reeds and consequent loss of toad breeding habitat. This resulted in reduced recruitment and population growth despite the lack of significant loss of adult habitat. Our results underscore the value of using long-term time series to identify shifts in population dynamics coincident with the advent of population decline. © 2013 Society for Conservation Biology.

Trypanosoma mega (Kinetoplastida) from Bufo viridis in Siwah Oasis, Egypt.

PubMed

Ashour, A A; Gaafar, N A

1997-04-01

A large pleomorphic trypanosome, identified as Trypanosoma mega, is described from the toad Bufo viridis collected from Siwah Oasis at the Western Desert of Egypt. The prevalence of the trypanosome is 83.3%. Three trypanosome forms are described, small, intermediate and large stumpy form. Observations were also made on the lysed (diffused) trypanosomes. This is the first record of T. mega from B. viridis in Egypt which represents a new host and new geographical location. The measurements of the present trypanosome are given and compared with related forms previously described from Egypt.

Estimation of temporary emigration in male toads

USGS Publications Warehouse

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

2006-01-01

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

Fatal attraction: adaptations to prey on native frogs imperil snakes after invasion of toxic toads.

PubMed

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

2009-08-07

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

The ecological impact of invasive cane toads on tropical snakes: field data do not support laboratory-based predictions.

PubMed

Brown, Gregory P; Phillips, Benjamin L; Shine, Richard

2011-02-01

Predicting which species will be affected by an invasive taxon is critical to developing conservation priorities, but this is a difficult task. A previous study on the impact of invasive cane toads (Bufo marinus) on Australian snakes attempted to predict vulnerability a priori based on the assumptions that any snake species that eats frogs, and is vulnerable to toad toxins, may be at risk from the toad invasion. We used time-series analyses to evaluate the accuracy of that prediction, based on >3600 standardized nocturnal surveys over a 138-month period on 12 species of snakes and lizards on a floodplain in the Australian wet-dry tropics, bracketing the arrival of cane toads at this site. Contrary to prediction, encounter rates with most species were unaffected by toad arrival, and some taxa predicted to be vulnerable to toads increased rather than declined (e.g., death adder Acanthophis praelongus; Children's python Antaresia childreni). Indirect positive effects of toad invasion (perhaps mediated by toad-induced mortality of predatory varanid lizards) and stochastic weather events outweighed effects of toad invasion for most snake species. Our study casts doubt on the ability of a priori desktop studies, or short-term field surveys, to predict or document the ecological impact of invasive species.

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

PubMed Central

2008-01-01

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

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

PubMed

Stöck, Matthias; Sicilia, Alessandra; Belfiore, Natalia M; Buckley, David; Lo Brutto, Sabrina; Lo Valvo, Mario; Arculeo, Marco

2008-02-23

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

Adapting to an invasive species: toxic cane toads induce morphological change in Australian snakes.

PubMed

Phillips, Ben L; Shine, Richard

2004-12-07

The arrival of invasive species can devastate natural ecosystems, but the long-term effects of invasion are less clear. If native organisms can adapt to the presence of the invader, the severity of impact will decline with time. In Australia, invasive cane toads (Bufo marinus) are highly toxic to most snakes that attempt to eat them. Because snakes are gape-limited predators with strong negative allometry for head size, maximum relative prey mass (and thus, the probability of eating a toad large enough to be fatal) decreases with an increase in snake body size. Thus, the arrival of toads should exert selection on snake morphology, favoring an increase in mean body size and a decrease in relative head size. We tested these predictions with data from specimens of four species of Australian snakes, collected over >80 years. Geographic information system layers provided data on the duration of toad exposure for each snake population, as well as environmental variables (latitude, precipitation, and temperature). As predicted, two toad-vulnerable species (Pseudechis porphyriacus and Dendrelaphis punctulatus) showed a steady reduction in gape size and a steady increase in body length with time since exposure to toads. In contrast, two species at low risk from toads (Hemiaspis signata and Tropidonophis mairii) showed no consistent change in these morphological traits as a function of the duration of toad exposure. These results provide strong evidence of adaptive changes in native predators as a result of the invasion of toxic prey.

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

PubMed

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

2017-01-01

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

Cardiovascular reflexes in conscious toads.

PubMed

Hoffmann, A; de Souza, M B

1982-05-01

Methods used for implanting sensors and catheters in temporarily ether-anesthetized toads (Bufo paracnemis) are described. Following recovery it was found that distension of the pulmocutaneous arterial trunk and high frequency electrical stimulation of the laryngeal nerve of conscious toads induce an abrupt fall in arterial pressure accompanied or not by bradycardia or cardiac arrest. A brief suppression of throat movements may occur but this is not a constant finding. The response is blocked by atropine or methyl-homatropine and persists in animals with high spinal sectioning, thus indicating its cholinergic parasympathetic nature. However a certain amount of sympathetic inhibition is not ruled out. Perfusion of the artery with lobeline and electrical stimulation of the laryngeal nerve at low frequency (1/s) induces a rise in arterial pressure which is blocked by phentolamine. The hypertension is followed by enhancing of both throat oscillations and electromyographic discharges. The occurrence of chemoreceptors in the pulmocutaneous arterial wall in these animals is discussed. Blockage of the laryngeal nerve with lidocaine or perfusion of the pulmocutaneous arterial trunk with the same solution elicited a blood pressure rise, tachycardia and enhanced ventilatory movements. This was attributed to suppression of the baroreceptor tonus.

Effect of human gonadotropins on spermiation and androgen biosynthesis in the testis of the toad Bufo arenarum (Amphibia, Anura).

PubMed

Pozzi, Andrea Gabriela; Rosemblit, Cinthia; Ceballos, Nora Raquel

2006-01-01

This paper analyzes, in the toad Bufo arenarum, the effect on spermiation and androgen secretion of two human recombinant gonadotropins, human recombinant LH (hrLH) and human recombinant FSH (hrFSH) as well as the well-known spermiation-inducing hormone, human chorionic gonadotropin (hCG). For this purpose, testes were incubated with different concentrations of hrLH (0.01-2.5 microg/ml) and hrFSH (0.05-5 microg/ml), and results were compared with those obtained with 2.5 microg/ml hCG. Spermiation was most efficiently stimulated by hrFSH, which elicited a higher response than either hrLH or hCG. Both hrFSH and hrLH produced a bell-shaped dose-response curve, with a 50% inhibition on spermiation at a concentration twice higher than that necessary to get the highest response. However, none of the gonadotropins yielded a biphasic response on androgen secretion, hrLH producing the highest response at a concentration that evoked a 70% inhibition in the spermiation test. Regarding steroidogenesis, hrLH and hrFSH were more active than hCG. Taken together, the results described in this paper suggest that, in B. arenarum, spermiation and androgen secretion are mediated by different receptors. After comparing the effects of recombinant hormones, we conclude that hrFSH has a greater effect on spermiation than hCG or hrLH.

Allozyme comparison of three Trypanosoma species (Kinetoplastida: Trypanosomatidae) of toads and frogs by starch-gel electrophoresis.

PubMed

Martin, D S; Desser, S S; Hong, H

1992-04-01

Six metabolic enzymes, glucose-6-phosphate dehydrogenase, glucosephosphate isomerase, isocitrate dehydrogenase, malate dehydrogenase, phosphoglucomutase, and purine nucleoside phosphorylase, from clonal isolates of 3 presumptive species of Trypanosoma (T. fallisi, T. ranarum, and T. rotatorium) from 3 anuran hosts (Bufo americanus, Rana clamitans, and Rana catesbeiana) were compared using starch-gel electrophoresis. Although bands were shared among the different zymodemes of isolates of the same host genus, low genetic polymorphism of the enzyme loci was observed with few apparent shared bands between samples isolated from frogs and toads. A distance value calculated between toad and frog trypanosome isolates suggests the likelihood of long-time separation of species. Cluster analysis based on overall similarity distinguished the trypanosomes of toads and frogs as separate taxa, suggesting that host specificity and observed morphological differences are consistent with heritable allozyme differences.

Apoptotic cell death in the central nervous system of Bufo arenarum tadpoles induced by cypermethrin.

PubMed

Casco, V H; Izaguirre, M F; Marín, L; Vergara, M N; Lajmanovich, R C; Peltzer, P; Soler, A Peralta

2006-05-01

Tadpoles of the toad Bufo arenarum treated with cypermethrin (CY) at concentrations above 39 mug CY/L showed dose-dependent apoptotic cell death in immature cells of the central nervous system as demonstrated by morphometric analysis, the TUNEL method, and DNA fragmentation assay. Light-and electron-microscopic studies showed structural alterations in the intermediate and marginal layers of the brain. Immature cerebral tissue showed cellular shrinkage, nuclear fragmentation and increase of intercellular spaces. In this study we demonstrated high toxicity of CY to larval stages of Bufo arenarum. Our results show that doses lower than those used in routine insecticide applications can cause massive apoptosis in the immature cells of the central nervous system. These results coincide with our previous studies in Physalaemus biligonigerus, confirming the severe toxic effects of CY to the central nervous system of anuran species from Argentina. This may increase the mortality index in wild animals and contribute to the loss of biodiversity in our agroecosystems. We postulate that CY induces apoptosis in central nervous system cells of Bufo arenarum tadpoles by specific neurotoxic mechanisms.

Influence of ambient ultraviolet radiation on Bufo calamita egg development in a semiarid zone (Catalonia, Spain).

PubMed

Oromi, Neus; Marquis, Olivier; Miaud, Claude; Sanuy, Delfi

2008-01-01

Several experiments have shown that ambient ultraviolet-B radiation (UV-B) has negative effects on the development of amphibians' embryos. We studied the effects of UV-B radiation on development, survival and frequency of deformity during egg development in the Natterjack toad (Bufo calamita) from a semiarid region of Lleida (Catalonia, Spain). Eggs exposed to ambient levels of UV-B and those protected from UV-B with a filter exhibited similar developmental rate, mortality rate and frequency of developmental anomalies. These experiments show that eggs of Bufo calamita of the studied population are able to develop normally during embryonic period when exposed to current high levels of UV-B observed in Catalonia. These results will be used as reference for future studies on geographic variation in UV-B tolerance in this species.

Evolutionary Responses to Invasion: Cane Toad Sympatric Fish Show Enhanced Avoidance Learning

PubMed Central

Caller, Georgina; Brown, Culum

2013-01-01

The introduced cane toad (Bufo marinus) poses a major threat to biodiversity due to its lifelong toxicity. Several terrestrial native Australian vertebrates are adapting to the cane toad’s presence and lab trials have demonstrated that repeated exposure to B. marinus can result in learnt avoidance behaviour. Here we investigated whether aversion learning is occurring in aquatic ecosystems by comparing cane toad naïve and sympatric populations of crimson spotted rainbow fish (Melanotaenia duboulayi). The first experiment indicated that fish from the sympatric population had pre-existing aversion to attacking cane toad tadpoles but also showed reduced attacks on native tadpoles. The second experiment revealed that fish from both naïve and sympatric populations learned to avoid cane toad tadpoles following repeated, direct exposure. Allopatric fish also developed a general aversion to tadpoles. The aversion learning abilities of both groups was examined using an experiment involving novel distasteful prey items. While both populations developed a general avoidance of edible pellets in the presence of distasteful pellets, only the sympatric population significantly reduced the number of attacks on the novel distasteful prey item. These results indicate that experience with toxic prey items over multiple generations can enhance avoidance leaning capabilities via natural selection. PMID:23372788

Structure-activity studies of bufokinin, substance P and their C-terminal fragments at bufokinin receptors in the small intestine of the cane toad, Bufo marinus.

PubMed

Liu, Lu; Murray, Michael; Burcher, Elizabeth

2002-01-15

Bufokinin is a substance P-related tachykinin peptide with potent spasmogenic actions, isolated from the intestine of the cane toad, Bufo marinus. Bufokinin acts via a tachykinin receptor with similarities to the mammalian NK(1) receptor. In this structure-activity study of bufokinin, substance P (SP) and their C-terminal fragments, we have used isolated segments and homogenates of toad small intestine to compare the contractile potencies and abilities to compete for the binding of [125I]-Bolton-Hunter bufokinin. In general, potency was very similar in both studies (r=0.956) and was primarily related to peptide length, with the natural undecapeptide tachykinins bufokinin - ranakinin>SP- cod SP -trout SP being most potent. The weakest peptides were [Pro(9)]SP, BUF(7-11) and SP(7-11). Bufokinin fragments (BUF) were approximately equipotent to the corresponding SP fragments, with only BUF(5-11) showing unexpectedly low binding affinity. Data obtained with SP, bufokinin and fragments were subjected to quantitative structure--activity (QSAR) analysis which demonstrated that molecular connectivity and shape descriptors yielded significant regression equations (r approximately 0.90). The predictive capacity of the equations was confirmed using ranakinin, trout SP and cod SP, but not using the synthetic analogs [Pro(9)]SP and [Sar(9)]SP. The study suggests that the full undecapeptide sequence of bufokinin is required for optimal activity, with high potency conferred by Lys(1), Pro(2), Gly(9) and probably Tyr(8). The finding that receptor-ligand interactions were correlated with the shape descriptor 2kappa(alpha) and favored by basic and rigid residues at position 1-3 is consistent with an important role of conformation at the N-terminus of bufokinin.

Alterations induced by E-cadherin and beta-catenin antibodies during the development of Bufo arenarum (Anura-Bufonidae).

PubMed

Izaguirre, M F; Adur, J F; Soler, A P; Casco, V H

2001-10-01

E(epithelial)-cadherin is a member of a calcium-dependent family of cell surface glycoproteins involved in cell-cell adhesion and morphogenesis. Catenins are a large family of proteins that connect the cadherins to the cytoskeleton. They are important for cadherin function and for transducing signals involved in specification of cell fate during embryogenesis. The best characterized catenins include alpha-, beta-, gamma-, and p120-catenin. Using specific antibodies, we studied the expression and distribution of E-cadherin, and alpha- and beta-catenin in developmental stages of Bufo arenarum toad. The three proteins were found co-localized in stages 19 to 41 of development. Surprisingly, E-cadherin was the only of these three proteins found earlier than stage 19. To test whether E-cadherin and beta-catenin have a functional role in Bufo arenarum embryogenesis, stage 17 whole embryos were incubated with anti-E-cadherin and beta-catenin antibodies. Both anti-E-cadherin and anti-beta-catenin antibodies induced severe morphological alterations. However, while alterations produced by the anti-beta-catenin antibody, showed some variability from the most severe (neural tube and notochord duplication) to a simple delay in development, the alterations with anti-E-cadherin were homogeneous. These observations suggest a critical role for E-cadherin and beta-catenin in the early embryonic development of the Bufo arenarum toad. Our results are consistent with the developmental role of these proteins in other species. One of the most surprising findings was the blockage with the anti-beta-catenin antibodies on later embryo stages, and we hypothesize that the partial axes duplication could be mediated by the notochord induction.

Morphological and molecular evidence for a new species of the genus Cosmocercoides Wilkie, 1930 (Ascaridida: Cosmocercidae) from the Asiatic toad Bufo gargarizans Cantor (Amphibia: Anura).

PubMed

Chen, Hui-Xia; Zhang, Lu-Ping; Nakao, Minoru; Li, Liang

2018-06-01

A new cosmocercid species, Cosmocercoides qingtianensis sp. n., collected from the intestine of the Asiatic toad Bufo gargarizans Cantor (Amphibia: Anura) is described using integrated approaches, including light and scanning electron microscopy, and sequencing and analyzing the ribosomal [small ribosomal DNA (18S) and internal transcribed spacer (ITS)] and mitochondrial [cytochrome c oxidase subunit 1 (cox1)] target regions, respectively. The new species can be distinguished from its congeners by the combination of the following morphological characters, including the large body size, the presence of lateral alae and somatic papillae in both sexes, the length of spicules, the particular morphology and length of gubernaculum, the number, arrangement and morphology of caudal rosettes, the presence of large medioventral precloacal papilla and the long tail. Our molecular analysis revealed the level of intraspecific genetic variation of C. qingtianensis sp. n. distinctly lower than that of the interspecific genetic variation in the ITS and cox1 regions. However, there are some overlaps in the range of intra- and interspecific 18S sequence divergence between the new species and some closely related species. The results of molecular analysis supported the validity of the new species based on the morphological observations. The 18S, ITS, and cox1 regions of C. pulcher collected from Bufo japonicus formosus in Japan were also sequenced and analyzed. The results showed a low level of intraspecific genetic variation in 18S and ITS regions (0-0.12% and 0-0.23% nucleotide differences, respectively), but a relatively high level of intraspecific genetic variation in cox1 region (0.78-4.69% nucleotide differences). In addition, it seems more powerful and practical to use the cox1 region as a genetic marker for the accurate identification and differentiation of species of Cosmocercoides than the 18S and ITS regions, especially for the closely related species.

Breeding habit of the toad Bufo coccifer in Costa Rica, with a description of the tadpole

USGS Publications Warehouse

McDiarmid, R.W.; Foster, M.S.

1981-01-01

The breeding habits of Bufo coccifer were studied in northwestern Costa Rica between 1971 and 1974. This species breeds during the rainy season, at least from May through August. Males chorus from areas of shallow water. Their calls resemble those of Mexican representatives of the species in pulse rate and duration, but are closer to those of other Costa Rican and Panamanian populations in dominant frequency. Thus, our data do not clearly support recognition of Bufo cycladen as a distinct species for the Mexican populations. Amplexus is axillary, and two strings of eggs are extruded simultaneously during oviposition. Tadpoles, described for the first time in this paper, are secretive and do not aggregate. Development to metamorphosis requires about 5 weeks.

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

USGS Publications Warehouse

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

2011-01-01

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

Purification of PRL receptors from toad kidney: Comparisons with rabbit mammary PRL receptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunand, M.; Kraehenbuhl, J.P.; Rossier, B.C.

1988-03-01

The binding characteristics of the prolactin (PRL) receptors present in toad (Bufo marinus) kidneys were investigated and compared to those of PRL receptors present in rabbit mammary glands. The molecular characteristics of the Triton X-100 solubilized renal and mammary PRL receptors were assessed by gel filtration and by migration analysis on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) after affinity labeling of the binding sites with {sup 125}I-human growth hormone. Similar results were obtained for both receptors. Partial purification of the toad PRL receptor could be achieved by affinity chromatography. The molecular weight of this purified receptor could be determined bymore » analysis of SDS-PAGE. With the use of a polyclonal antiserum raised against a purified preparation of rabbit mammary PRL receptor, one or several antigenic epitope(s) could be identified on the core of the toad renal PRL receptor. In conclusion, although the structure and the biological role(s) of PRL have substantially changed during evolution, the receptor for this hormone has retained many of its structural features as could be assessed between an amphibian and a mammalian species on functionally different target tissues.« less

Hybrid zone formation and contrasting outcomes of secondary contact over transects in common toads.

PubMed

Arntzen, Jan W; de Vries, Wouter; Canestrelli, Daniele; Martínez-Solano, Iñigo

2017-10-01

Much progress in speciation research stems from documenting patterns of morphological and genetic variation in hybrid zones. Contrasting patterns of marker introgression in different sections of the contact can provide valuable insights on the relative importance of various evolutionary mechanisms maintaining species differences in the face of hybridization and gene flow and on hybrid zone temporal and spatial dynamics. We studied species interactions in the common toads Bufo bufo and B. spinosus in France and northwestern Italy using morphological and molecular data from the mitochondrial and nuclear genomes in an extensive survey, including two independent transects west and east of the Alps. At both, we found sharp, coincident and concordant nuclear genetic transitions. However, morphological clines were wider or absent and mtDNA introgression was asymmetric. We discuss alternative, nonexclusive hypotheses about evolutionary processes generating these patterns, including drift, selection, long-distance dispersal and spatial shifts in hybrid zone location and structure. The distribution of intraspecific mtDNA lineages supports a scenario in which B. bufo held a local refugium during the last glacial maximum. Present-day genetic profiles are best explained by an advance of B. spinosus from a nearby Iberian refugium, largely superseding the local B. bufo population, followed by an advance of B. bufo from the Balkans, with prongs north and south of the Alps, driving B. spinosus southwards. A pendulum moving hybrid zone, first northwards and then southwards, explains the wide areas of introgression at either side of the current position of the contact zones. © 2017 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Antioxidant responses to azinphos methyl and carbaryl during the embryonic development of the toad Rhinella (Bufo) arenarum Hensel.

PubMed

Ferrari, Ana; Lascano, Cecilia I; Anguiano, Olga L; D'Angelo, Ana M Pechen de; Venturino, Andrés

2009-06-04

Amphibian embryos are naturally exposed to prooxidant conditions throughout their development. Environmental exposure to contaminants may affect their capacity to respond to challenging conditions, to progress in a normal ontogenesis, and finally to survive and succeed in completing metamorphosis. We studied the effects of the exposure to two anticholinesterase agents, the carbamate carbaryl and the organophosphate azinphos methyl, on the antioxidant defenses of developing embryos of the toad Rhinella (Bufo) arenarum. Reduced glutathione (GSH) levels were increased early by carbaryl, but were decreased by both pesticides at the end of embryonic development. The GSH-dependent enzymes glutathione reductase and glutathione peroxidases showed oscillating activity patterns that could be attributed to an induction of activity in response to oxidative stress and inactivation by excess of reactive oxygen species. Glutathione-S-transferases, which may participate in the conjugation of lipid peroxide products in addition to pesticide detoxification, showed an increase of activity at the beginning and at the end of development. Catalase also showed variations in the activity suggesting, successively, induction and inactivation in response to pesticide exposure-induced oxidative stress. Superoxide dismutase activity was increased by carbaryl and transiently decreased by azinphos methyl exposure. Judging from the depletion in GSH levels and glutathione reductase inhibition at the end of embryonic development, the oxidative stress caused by azinphos methyl seemed to be greater than that caused by carbaryl, which might be in turn related with a higher number of developmental alterations caused by the organophosphate. GSH content is a good biomarker of oxidative stress in the developing embryos exposed to pesticides. The antioxidant enzymes are in turn revealing the balance between their protective capacity and the oxidative damage to the enzyme molecules, decreasing their

Cellular composition of the islets of langerhans in the himalayan toad, Bufo melanostictus (Schneider): a light microscopical study.

PubMed

Nanda, S; Bisht, J S; Bhatt, S D

1975-01-01

The pancreatic islet tissue of Bufo melanostictus, investigated by differential staining techniques, is generally condensed in the anterior and middle regions, and contains distinguishable islets of various size, shape and or irregular configuration. Histologically, 3 distinct cell types have been identified: B, A1 and A2. Various tinctorial characteristics of B cells reveal that they correspond to the insulin producing B-cells of other vertebrates. The A cells are a few in number, some of which definitely show positive argyrophilia (= A1). A few isolated A- and B-cells are found scattered in the exocrine tissue. A conspicuous feature of several B-cells in some specimens of Bufo melanostictus is the presence of vacuoles of varying size.

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

USGS Publications Warehouse

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

2008-01-01

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

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

USGS Publications Warehouse

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

2004-01-01

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frazier, L.W.; Yorio, T.

1990-05-01

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

TOAD Editor

NASA Technical Reports Server (NTRS)

Bingle, Bradford D.; Shea, Anne L.; Hofler, Alicia S.

1993-01-01

Transferable Output ASCII Data (TOAD) computer program (LAR-13755), implements format designed to facilitate transfer of data across communication networks and dissimilar host computer systems. Any data file conforming to TOAD format standard called TOAD file. TOAD Editor is interactive software tool for manipulating contents of TOAD files. Commonly used to extract filtered subsets of data for visualization of results of computation. Also offers such user-oriented features as on-line help, clear English error messages, startup file, macroinstructions defined by user, command history, user variables, UNDO features, and full complement of mathematical statistical, and conversion functions. Companion program, TOAD Gateway (LAR-14484), converts data files from variety of other file formats to that of TOAD. TOAD Editor written in FORTRAN 77.

Distribution and pathogenicity of Batrachochytrium dendrobatidis in boreal toads from the grand teton area of western wyoming

USGS Publications Warehouse

Murphy, P.J.; St-Hilaire, S.; Bruer, S.; Corn, P.S.; Peterson, C.R.

2009-01-01

The pathogen Batrachochytrium dendrobatidis (Bd), which causes the skin disease chytridiomycosis, has been linked to amphibian population declines and extinctions worldwide. Bd has been implicated in recent declines of boreal toads, Bufo boreas boreas, in Colorado but populations of boreal toads in western Wyoming have high prevalence of Bd without suffering catastrophic mortality. In a field and laboratory study, we investigated the prevalence of Bd in boreal toads from the Grand Teton ecosystem (GRTE) in Wyoming and tested the pathogenicity of Bd to these toads in several environments. The pathogen was present in breeding adults at all 10 sites sampled, with a mean prevalence of 67%. In an experiment with juvenile toadlets housed individually in wet environments, 106 zoospores of Bd isolated from GRTE caused lethal disease in all Wyoming and Colorado animals within 35 days. Survival time was longer in toadlets from Wyoming than Colorado and in toadlets spending more time in dry sites. In a second trial involving Colorado toadlets exposed to 35% fewer Bd zoospores, infection peaked and subsided over 68 days with no lethal chytridiomycosis in any treatment. However, compared with drier aquaria with dry refuges, Bd infection intensity was 41% higher in more humid aquaria and 81% higher without dry refuges available. Our findings suggest that although widely infected in nature, Wyoming toads may escape chytridiomycosis due to a slight advantage in innate resistance or because their native habitat hinders Bd growth or provides more opportunities to reduce pathogen loads behaviorally than in Colorado. ?? 2009 International Association for Ecology and Health.

Analgesic Effects of Toad Cake and Toad-cake-containing Herbal Drugs: Analgesic effects of toad cake.

PubMed

Inoue, Eiji; Shimizu, Yasuharu; Masui, Ryo; Usui, Tomomi; Sudoh, Keiichi

2014-03-01

This study was conducted to clarify the analgesic effect of toad cake and toad-cake-containing herbal drugs. We counted the writhing response of mice after the intraperitoneal administration of acetic acid as a nociceptive pain model and the withdrawal response after the plantar surface stimulation of the hind paw induced by partial sciatic nerve ligation of the mice as a neuropathic pain model to investigate the analgesic effect of toad cake and toad-cake-containing herbal drugs. A co-treatment study with serotonin biosynthesis inhibitory drug 4-chloro- DL-phenylalanine methyl ester hydrochloride (PCPA), the catecholamine biosynthesis inhibitory drug α-methyl- DL-tyrosine methyl ester hydrochloride (AMPT) or the opioid receptor antagonist naloxone hydrochloride was also conducted. Analgesic effects in a mouse model of nociceptive pain and neuropathic pain were shown by oral administration of toad cake and toad-cake-containing herbal drugs. The effects of toad cake and toad-cake-containing herbal drugs disappeared upon co-treatment with PCPA, but not with AMPT or naloxone in the nociceptive pain model; the analgesic effect of toad-cake-containing herbal drugs also disappeared upon co-treatment with PCPA in the neuropathic pain model. Toad cake and toad-cake-containing herbal drugs have potential for the treatments of nociceptive pain and of neuropathic pain, such as post-herpetic neuralgia, trigeminal neuralgia, diabetic neuralgia, and postoperative or posttraumatic pain, by activation of the central serotonin nervous system.

Protective effect of taurine on cardiotoxicity of the bufadienolides derived from toad (Bufo bufo gargarizans Canto) venom in guinea-pigs in vivo and in vitro.

PubMed

Ma, Hongyue; Jiang, Jiejun; Zhang, Junfeng; Zhou, Jing; Ding, Anwei; Lv, Gaohong; Xu, Huiqin; You, Fenqiang; Zhan, Zhen; Duan, Jinao

2012-01-01

In China, toad venom is an anti-inflammatory agent used in small doses for the treatment of various types of inflammation. Bufadienolides are cardioactive steroids responsible for the anti-inflammatory actions of toad venom. We studied the protective effect of taurine on the cardiotoxicity of bufadienolides in guinea-pigs. Bufadienolides (8 mg/kg) caused arrhythmias, cardiac dysfunction and death in guinea-pigs. Pretreatment with taurine (150, 300 mg/kg) significantly prevented bufadienolide-induced cardiotoxicity and reduced the mortality in vivo. Taurine markedly increased the cumulative doses of bufadienolides and resibufogenin required for lethal arrhythmia in ex vivo isolated guinea-pig heart. Taurine did not compromise the anti-inflammatory activity of the bufadienolides on concanavalin-A-stimulated proliferation of guinea-pig splenocytes in vitro. These data indicate that taurine can prevent bufadienolide-induced cardiotoxicity and could be a novel antidote in combination with bufadienolide therapy.

Effect of salt acclimatization on 3 beta-hydroxysteroid dehydrogenase/isomerase activity in the interrenal of Bufo arenarum.

PubMed

Pozzi, Andrea G; Lantos, Carlos P; Ceballos, Nora R

2002-03-01

In amphibians, aldosterone (Aldo) is particularly important in the regulation of Na(+) exchange by skin and urinary bladder. In previous works we studied a key enzyme in Aldo biosynthesis, the 3 beta-hydroxysteroid dehydrogenase/isomerase (3 beta HSD/I), in the interrenals of Bufo arenarum. In those works a dual localization of the 3 beta HSD/I in both microsomes and mitochondria was described. The mitochondrial, but not the microsomal, enzyme prefers the immediate Aldo precursor, 3 beta-analogue of aldosterone, as substrate. In this order, the enzyme 3 beta HSD/I would be not only a key enzyme for the synthesis of Aldo but additionally, due to its microsomal and mitochondrial localization, a possible target for the regulation of Aldo biosynthesis. With this rationale in mind, we have used in vivo and in vitro approaches to study Aldo regulation. In the present investigation the levels of Aldo were determined in plasma of winter (W) and summer (S) toads subjected to different saline concentrations (0.125 and 0.15 M) or kept on wet land. Saline hyperosmotically treated toads had significantly lower levels than isoosmotically treated toads. These results are consistent with the response in mammals, in which salt loading provokes a reduction in Aldo secretion. In W toads, plasmatic corticosterone (B) concentration was higher than Aldo concentration, whereas in S toads, B/Aldo ratio approached unity. The reduction of Aldo levels after saline dehydration was due to a decline in its biosynthesis. K(m) and V(max) values for 3 beta HSD/I were calculated for mitochondrial and microsomal fractions obtained from animals acclimated to 0.15 M NaCl or kept on land. As previously described, V(max) differs between W and S toads. However, only mitochondrial V(max) changed as a consequence of saline adaptation, suggesting that the mitochondrial enzyme could be involved in the regulation of Aldo biosynthesis.

Chemical profiling and cytotoxicity assay of bufadienolides in toad venom and toad skin.

PubMed

Meng, Qiong; Yau, Lee-Fong; Lu, Jing-Guang; Wu, Zhen-Zhen; Zhang, Bao-Xian; Wang, Jing-Rong; Jiang, Zhi-Hong

2016-07-01

Toad venom and toad skin have been widely used for treating various cancers in China. Bufadienolides are regarded as the main anticancer components of toad venom, but the difference on composition and anticancer activities of bufadienolides between toad venom and toad skin remains unclear. Fractions enriched with free and conjugated bufadienolides were prepared from toad venom and toad skin. Bufadienolides in each fraction were comprehensively profiled by using a versatile UHPLC-TOF-MS method. Relative contents of major bufadienolides were determined by using three bufogenins and one bufotoxin as marker compounds with validated UHPLC-TOF-MS method. Furthermore, cytotoxicity of the fractions was examined by MTT assay. Two fractions, i.e., bufogenin and bufotoxin fractions (TV-F and TV-C) were isolated from toad venom, and one bufotoxin fraction (TS-C) was isolated from toad skin. Totally 56 bufadienolides in these three fractions were identified, and 29 were quantified or semi-quantified. Bufotoxins were identified in both toad venom and toad skin, whereas bufogenins exist only in toad venom. Bufalin-3-conjugated bufotoxins are major components in toad venom, whereas cinobufotalin and cinobufagin-3-conjugated bufotoxins are main bufotoxins in toad skin. MTT assay revealed potent cytotoxicity of all the fractions in an order of TV-F>TV-C>TS-C. Our study represents the most comprehensive investigation on the chemical profiles of toad venom and toad skin from both qualitative and quantitative aspects. Eight bufotoxins were identified in toad skin responsible for the cytotoxicity for the first time. Our research provides valuable chemical evidence for the appropriate processing method, quality control and rational exploration of toad skin and toad venom for the development of anticancer medicines. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Distribution of boreal toad populations in relation to estimated UV-B dose in Glacier National Park, Montana, USA

USGS Publications Warehouse

Hossack, B.R.; Diamond, S.A.; Corn, P.S.

2006-01-01

A recent increase in ultraviolet B radiation is one hypothesis advanced to explain suspected or documented declines of the boreal toad (Bufo boreas Baird and Girard, 1852) across much of the western USA, where some experiments have shown ambient UV-B can reduce embryo survival. We examined B. boreas occupancy relative to daily UV-B dose at 172 potential breeding sites in Glacier National Park, Montana, to assess whether UV-B limits the distribution of toads. Dose estimates were based on ground-level UV-B data and the effects of elevation, local topographic and vegetative features, and attenuation in the water column. We also examined temporal trends in surface UV-B and spring snowpack to determine whether populations are likely to have experienced increased UV-B exposure in recent decades. We found no support for the hypothesis that UV-B limits the distribution of populations in the park, even when we analyzed high-elevation ponds separately. Instead, toads were more likely to breed in water bodies with higher estimated UV-B doses. The lack of a detectable trend in surface UV-B since 1979, combined with earlier snow melt in the region and increasing forest density at high elevations, suggests B. boreas embryos and larvae likely have not experienced increased UV-B.

Analgesic Effects of Toad Cake and Toad-cake-containing Herbal Drugs

PubMed Central

Inoue, Eiji; Shimizu, Yasuharu; Masui, Ryo; Usui, Tomomi; Sudoh, Keiichi

2014-01-01

Objectives: This study was conducted to clarify the analgesic effect of toad cake and toad-cake-containing herbal drugs. Methods: We counted the writhing response of mice after the intraperitoneal administration of acetic acid as a nociceptive pain model and the withdrawal response after the plantar surface stimulation of the hind paw induced by partial sciatic nerve ligation of the mice as a neuropathic pain model to investigate the analgesic effect of toad cake and toad-cake-containing herbal drugs. A co-treatment study with serotonin biosynthesis inhibitory drug 4-chloro- DL-phenylalanine methyl ester hydrochloride (PCPA), the catecholamine biosynthesis inhibitory drug α-methyl- DL-tyrosine methyl ester hydrochloride (AMPT) or the opioid receptor antagonist naloxone hydrochloride was also conducted. Results: Analgesic effects in a mouse model of nociceptive pain and neuropathic pain were shown by oral administration of toad cake and toad-cake-containing herbal drugs. The effects of toad cake and toad-cake-containing herbal drugs disappeared upon co-treatment with PCPA, but not with AMPT or naloxone in the nociceptive pain model; the analgesic effect of toad-cake-containing herbal drugs also disappeared upon co-treatment with PCPA in the neuropathic pain model. Conclusion: Toad cake and toad-cake-containing herbal drugs have potential for the treatments of nociceptive pain and of neuropathic pain, such as post-herpetic neuralgia, trigeminal neuralgia, diabetic neuralgia, and postoperative or posttraumatic pain, by activation of the central serotonin nervous system. PMID:25780693

Oxygen-sensitive regulatory volume increase and Na transport in red blood cells from the cane toad, Bufo marinus.

PubMed

Kristensen, Karina; Koldkjaer, Pia; Berenbrink, Michael; Wang, Tobias

2007-07-01

The red blood cells (RBCs) of cane toad, Bufo marinus, are only partially saturated with oxygen in most of the circulation due to cardiac shunts that cause desaturation of arterial blood. The present study examines the oxygen dependency of RBC ouabain-insensitive unidirectional Na transport, using 22Na, in control cells and in cells exposed to hyperosmotic shrinkage or the beta-adrenergic agonist isoproterenol. Deoxygenation per se induced a slow, but significant Na influx, which was paralleled by a slow increase in RBC volume. Hyperosmotic shrinkage by a calculated 25% activated a robust Na influx that in the first 30 min had a strong PO2 dependency with maximal activation at low PO2 values and a P50 of approximately 5.5 kPa. This activation was completely abolished by the Na/H exchanger (NHE) inhibitor EIPA (10(-4) mol l(-1)). Hyperosmotic shrinkage is particularly interesting in B. marinus as it withstands considerable elevation in extracellular osmolarity following dehydration. Parallel studies showed that deoxygenated B. marinus RBCs had a much faster regulatory volume increase (RVI) response than air-equilibrated RBCs, reflecting the difference in magnitude of Na influxes at the two PO2 values. The extent of RVI ( approximately 60%) after 90 min, however, was similar under the two conditions, reflecting a more prolonged elevation of the shrinkage-induced Na influx in air-equilibrated RBCs. There were no significant differences in the ability to perform RVI between whole blood cells at a PCO2 of 1 and 3 kPa or washed RBCs, and 10(-4) mol l(-1) amiloride reduced the RVI under all conditions, whereas 10(-5) mol l(-1) bumetanide had no effect. Isoproterenol (10(-5) mol l(-1)) induced a significant and prolonged increase in an EIPA-sensitive and bumetanide-insensitive Na influx at low PO2 under iso-osmotic conditions, whilst there was no stimulation by isoproterenol for up to 45 min in air-equilibrated RBCs. The prolonged beta-adrenergic activation of the Na

Ecological energetics of three species of ectothermic vertebrates. [Snakes, toads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, G.C.

Comparisons were made of the energy budgets of three ectothermic vertebrates found in the southeastern United States. The three species studied were Elaphe guttata (corn snakes), Heterodon platyrhinos (eastern hognose snakes), and Bufo terrestris (southern toads). Values for assimilation efficiency, ingestion, excretion, growth, shedding, metabolism, and reproduction were converted to caloric units and integrated into energy flow models for each species. Elaphe guttata had a greater weekly ingestion rate than did the other two species in all weight classes. Assimilation efficiencies for the three species were 88.92 percent for E. guttata, 83.92 percent for H. platyrhinos, and 73.70 percent formore » B. terrestris. Regression equations of metabolism per animal hour at 15/sup 0/C, 20/sup 0/C, and 30/sup 0/C for the three species were presented. Reserves of fat in the three species coincided with periods of maximal reproduction suggesting that a large percentage of the energy reserves were utilized for this purpose. Elaphe guttata showed a much greater rate of growth than the other two species in the laboratory. Egg clutches comprised approximately 42 percent of the total caloric values of the females of all three species. Production-assimilation ratios (production/assimilation x 100) were 86 percent for corn snakes, 81 percent for hognose snakes, and 49 percent for southern toads. (JTE)« less

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

PubMed

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

2014-08-11

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

Heavy metal contamination in the river toad, Bufo juxtasper (Inger), near a copper mine in East Malaysia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Yook Heng; Stuebing, R.B.

1990-08-01

Mining of metals creates a potential source of heavy metal contamination in the environment. An open pit copper mine situated in the Northwest of Sabah, East Malaysia has been known to pollute its surroundings especially with discharges involving heavy metals. Although extensive investigations of heavy metal pollution has been carried out, none of the studies performed so far has included amphibians as indicator of heavy metal contamination in the area. As amphibians live both on land and in water, a study on the heavy metal content of these animals will thus enable a more extensive evaluation of the degree ofmore » contamination by heavy metals. Bufo juxtasper was chosen since it inhabits the rocky streams and rivers which exist in both a polluted and non-polluted condition in Sabah. Its' tadpoles are herbivorous feeding mainly on plant detritus, while adults feed principally on ants (which are polyphagous). Furthermore the large adult size of Bufo juxtasper, in which the size of the liver has an allometric relationship with body size, may allow for differentiation between larval and adult uptake through regression analysis. Thus concentration of pollutants acquired only during the larval phase should show a declining or negative slope as a function of body size in adults.« less

[Conseqquences of dorso-ventral and anterior-posterior reversion of early neurula lateral mesoblast on development of urogenital system in common toad, Bufo bufo. (Amphibia anura)].

PubMed

Hakim, J; Gipouloux, J D

1975-10-27

At early neurula stage of the toad, cranio-caudal and dorso-ventral reversal of lateral mesoblast is performed. The genito-urinary system is therefore missing after this intervention. The three following factors of the formation of this system anlage are anlyzed: lateral mesoderm competence, stimulative activites of dorso-caudal endoblast on the one hand, of chordo-mesoderm on the other hand.

When new human-modified habitats favour the expansion of an amphibian pioneer species: Evolutionary history of the natterjack toad (Bufo calamita) in a coal basin.

PubMed

Faucher, Leslie; Hénocq, Laura; Vanappelghem, Cédric; Rondel, Stéphanie; Quevillart, Robin; Gallina, Sophie; Godé, Cécile; Jaquiéry, Julie; Arnaud, Jean-François

2017-09-01

Human activities affect microevolutionary dynamics by inducing environmental changes. In particular, land cover conversion and loss of native habitats decrease genetic diversity and jeopardize the adaptive ability of populations. Nonetheless, new anthropogenic habitats can also promote the successful establishment of emblematic pioneer species. We investigated this issue by examining the population genetic features and evolutionary history of the natterjack toad (Bufo [Epidalea] calamita) in northern France, where populations can be found in native coastal habitats and coalfield habitats shaped by European industrial history, along with an additional set of European populations located outside this focal area. We predicted contrasting patterns of genetic structure, with newly settled coalfield populations departing from migration-drift equilibrium. As expected, coalfield populations showed a mosaic of genetically divergent populations with short-range patterns of gene flow, and native coastal populations indicated an equilibrium state with an isolation-by-distance pattern suggestive of postglacial range expansion. However, coalfield populations exhibited (i) high levels of genetic diversity, (ii) no evidence of local inbreeding or reduced effective population size and (iii) multiple maternal mitochondrial lineages, a genetic footprint depicting independent colonization events. Furthermore, approximate Bayesian computations suggested several evolutionary trajectories from ancient isolation in glacial refugia during the Pleistocene, with biogeographical signatures of recent expansion probably confounded by human-mediated mixing of different lineages. From an evolutionary and conservation perspective, this study highlights the ecological value of industrial areas, provided that ongoing regional gene flow is ensured within the existing lineage boundaries. © 2017 John Wiley & Sons Ltd.

Berberine-induced pigment dispersion in Bufo melanostictus melanophores by stimulation of beta-2 adrenergic receptors.

PubMed

Ali, Sharique A; Naaz, Ishrat; Choudhary, Ram Kumar

2014-02-01

Reduced production of melanin by decreased or the absence of melanocytes leads to various hypopigmentation disorders, and the development of melanogenetic agents for photoprotection and hypopigmentation disorders is one of the top priority areas of research. Hence, the present study was carried out to elucidate the ability of berberine, a principal active ingredient present in the roots of the herb Berberis vulgaris to stimulate pigment dispersion in the isolated skin melanophores of the toad Bufo melanostictus. In the present study, mean melanophore size index of the isolated skin melanophores of B. melanostictus was assayed after treating with various concentrations of berberine. A marked melanin dispersion response leading to skin darkening was observed in the isolated melanophores of toad in response to berberine, which was found to be mediated through beta-2 adrenergic receptors. The physiologically significant dose-related melanin dispersion effects of berberine per se were found to be completely abolished by propranolol, which is a specific beta-2 adrenergic receptor blocker. These per se melanin dispersal effects were also found to be markedly potentiated by isoprenaline, which is a specific beta-adrenoceptor agonist. The results indicate that berberine causes a tremendous, dose-dependent, physiologically significant pigment dispersing in the isolated skin melanophores of B. melanostictus.

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

USGS Publications Warehouse

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

2014-01-01

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

Effects of mGnRH on testicular steroidogenesis in the toad Bufo arenarum.

PubMed

Canosa, Luis F; Pozzi, Andrea G; Somoza, Gustavo M; Ceballos, Nora R

2002-06-15

GnRH controls vertebrate reproduction in several ways. This hormone not only affects the secretion of gonadotropins from the pituitary gland but also has a direct influence on several gonadal functions such as steroidogenesis, spermatogenesis, and spermiation. In the present paper we have studied the in vitro effects of GnRH on the testicular steroidogenesis of Bufo arenarum to ascertain the role of this peptide in the control of the steroidogenic pathway previously described in this species. It was found that GnRH is able to reduce basal as well as hCG-stimulated testosterone release, having an inhibitory effect on P450(c17) activity. Thus, GnRH could be involved in the mechanism that regulates the metabolic change in the testicular steroidogenesis. Additionally, testicular GnRH binding site has been characterised, showing a K(d) of 34 nM and a maximum binding of 4.7 pmol/mg protein. Copyright 2002 Elsevier Science (USA)

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

PubMed

Dorchin, A; Shanas, U

2010-12-01

Road runoff is a major source of environmental pollution, significantly threatening nearby aquatic habitats. Chemical analyses indicate high pollutant concentrations in the road's "first flush", but bioassays are more advantageous for addressing the cumulative effects of the numerous pollutants within the runoff. We used Bufo viridis embryos and larvae to assess the toxicity of road runoff from two major highways in Israel. We show, for the first time, that exposure to midseason runoff not only has an adverse effect on growth and development rates of B. viridis larvae but can also lead to increased rates of morphological deformations. Seasonal first flushes, despite having higher metal concentrations, did not adversely affect the toad larvae, apparently due to a counter effect of organic matter that potentially served as a supplementary energy resource. Road runoff can be a major cause for a qualitative decrease in the quality of aquatic habitats threatening amphibians in Israel. Copyright © 2010 Elsevier Ltd. All rights reserved.

Habitat suitability of patch types: a case study of the Yosemite toad

USGS Publications Warehouse

Liang, Christina T.; Stohlgren, Thomas J.

2011-01-01

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

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

PubMed

Pallister, Jackie A; Halliday, Damien C T; Robinson, Anthony J; Venables, Daryl; Voysey, Rhonda D; Boyle, Donna G; Shanmuganathan, Thayalini; Hardy, Christopher M; Siddon, Nicole A; Hyatt, Alex D

2011-01-25

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

Assessment of Virally Vectored Autoimmunity as a Biocontrol Strategy for Cane Toads

PubMed Central

Robinson, Anthony J.; Venables, Daryl; Voysey, Rhonda D.; Boyle, Donna G.; Shanmuganathan, Thayalini; Hardy, Christopher M.; Siddon, Nicole A.; Hyatt, Alex D.

2011-01-01

Background The cane toad, Bufo (Chaunus) marinus, is one of the most notorious vertebrate pests introduced into Australia over the last 200 years and, so far, efforts to identify a naturally occurring B. marinus-specific pathogen for use as a biological control agent have been unsuccessful. We explored an alternative approach that entailed genetically modifying a pathogen with broad host specificity so that it no longer caused disease, but carried a gene to disrupt the cane toad life cycle in a species specific manner. Methodology/Principal Findings The adult beta globin gene was selected as the model gene for proof of concept of autoimmunity as a biocontrol method for cane toads. A previous report showed injection of bullfrog tadpoles with adult beta globin resulted in an alteration in the form of beta globin expressed in metamorphs as well as reduced survival. In B. marinus we established for the first time that the switch from tadpole to adult globin exists. The effect of injecting B. marinus tadpoles with purified recombinant adult globin protein was then assessed using behavioural (swim speed in tadpoles and jump length in metamorphs), developmental (time to metamorphosis, weight and length at various developmental stages, protein profile of adult globin) and genetic (adult globin mRNA levels) measures. However, we were unable to detect any differences between treated and control animals. Further, globin delivery using Bohle iridovirus, an Australian ranavirus isolate belonging to the Iridovirus family, did not reduce the survival of metamorphs or alter the form of beta globin expressed in metamorphs. Conclusions/Significance While we were able to show for the first time that the switch from tadpole to adult globin does occur in B. marinus, we were not able to induce autoimmunity and disrupt metamorphosis. The short development time of B. marinus tadpoles may preclude this approach. PMID:21283623

Phylogeography of Bufo marinus from its natural and introduced ranges.

PubMed Central

Slade, R W; Moritz, C

1998-01-01

The marine toad, Bufo marinus, has a broad natural distribution extending from the south-west of the USA to southern Peru and the central Amazon. It was introduced to several localities in the Caribbean and Pacific Oceans to control sugar cane pests. We sequenced 468 bp of mitochondrial DNA (mtDNA) containing the ND3 gene, and flanking tRNA genes from toads spanning the broad natural and introduced ranges. Consistent with the known history of introductions and expected effects of serial bottlenecks, mtDNA within introduced populations in Hawaii and Australia was uniform and most closely related to samples from eastern Venezuela and French Guiana. However, mtDNA nucleotide diversity in the geographic region spanning the source areas is also relative low (0.18-0.46%) and the absence of variation in the introduced populations precludes quantitative assessment of the reduction in genetic diversity. Unexpectedly, there was a large phylogeographic break (5.4% sequence divergence) within the natural range separating populations east and west of the Venezuelan Andes. We hypothesize that the two major lineages of B. marinus were isolated by the uplift of the eastern Andean cordillera which was completed approximately 2.7 Ma. Another species of the marinus group, B. paracnemis, had mtDNA paraphyletic, with marinus, being nested within the eastern lineage. Thus, at least one speciation event within the marinus group postdates the split within marinus. These findings suggest that the taxonomy of B. marinus should be re-evaluated and that the search for pathogens to control Australian populations should be conducted in populations from both lineages in the natural range. PMID:9628036

Phylogeographic and population insights of the Asian common toad (Bufo gargarizans) in Korea and China: population isolation and expansions as response to the ice ages

PubMed Central

Santos, Joana L.; Sánchez-RamÍrez, Santiago; Bae, Yoonhyuk; Jang, Yikweon

2017-01-01

The effects of ice ages on speciation have been well documented for many European and North American taxa. In contrast, very few studies have addressed the consequences of such environmental and topographical changes in North East Asian species. More precisely, the Korean Peninsula offers a unique model to assess patterns and processes of speciation as it hosts the northern- and eastern-most distribution limit of some widespread Asian taxa. Despite this, studies addressing phylogeographic patterns and population genetics in the peninsula and surrounding countries are few and studies for most families are lacking. Here we inferred the phylogenetic relationships of the common toad (Bufo gargarizans) from South Korea and their North East Asian counterpart populations, based on mitochondrial data. Korean B. gargarizans GenBank BLASTs matched few individuals from nearby China, but the presence of a Korean clade suggests isolation on the Korean Peninsula, previous to the last glacial maximum, linked to sea level resurgence. Molecular clock calibrations within this group were used to date the divergence between clades and their relationship to paleo-climatic events in the area. Lack of genetic structure among South Korean populations and strong homogeneity between the Korean and some Chinese localities suggest weak isolation and recent expansion. Geographical projection of continuous coalescent maximum-clade-credibility trees shows an original Chinese expansion towards the Korean Peninsula through the Yellow Sea circa two million years ago with colonisation events dating circa 800 thousand years ago (K. y. a.). Following this colonisation, the data point to outgoing Korean Peninsula dispersal events throughout different periods, towards the North through land, and West through land bridge formations over the Yellow Sea during sea level falls. In accordance, demographic analyses revealed a population expansion in the Koran Peninsula circa 300 K. y. a., likely attributed to

Seasonal changes in testicular steroidogenesis in the toad Bufo arenarum H.

PubMed

Canosa, L F; Ceballos, N R

2002-02-15

The biosynthesis of androgens in Bufo arenarum takes place through the 5-ene pathway that includes 5-androstane-3beta,17beta-diol as intermediate in testosterone biosynthesis. Besides testosterone and 5alpha-dihydrotestosterone, testes are able to synthesize 5alpha-pregnan-3,20-dione and several 3alpha- and 20alpha-reduced derivatives. Steroid biosynthesis changes during the breeding period (spring and early summer), turning from androgen to C21 steroid production. During the reproductive season, the production of progesterone, 5alpha-pregnan-3alpha,20alpha-diol, 3alpha-hydroxy-5alpha-pregnan-20-one, and 5alpha-pregnan-3,20-dione increases significantly. The function of most of these steroids in amphibians remains unknown. However, 5alpha-androstan-3alpha,17beta-diol and 3alpha-hydroxy-5alpha-pregnan-20-one were shown to be neuroactive in mammals, modulating sexual behavior. Thus, 5alpha/3alpha-reduced steroids could be involved in the regulation of the reproductive behavior in B. arenarum, a species with a dissociated reproductive pattern. Percentage contribution of each enzymes to the total metabolism reveals that neither 3beta-hydroxysteroid dehydrogenase/isomerase nor 5alpha-reductase change throughout the reproductive cycle. However, a strong reduction in 17-hydroxylase-C(17-20) lyase activity occurs in the reproductive season, suggesting that this enzyme could represent a key enzyme in the regulation of the seasonal change of steroidogenesis. Also, 3alpha-hydroxysteroid dehydrogenase and 20-hydroxysteroid dehydrogenase activities increase during the reproductive period, implying that steroid metabolism is clearly focused on C21-reduced steroids. (C)2002 Elsevier Science (USA).

Chloride channel blockers activate an endogenous cationic current in oocytes of Bufo arenarum.

PubMed

Cavarra, M S; del Mónaco, S M; Kotsias, B A

2004-07-01

A two-electrode, voltage-clamp technique was used to measure the effect of the Cl(-) channel blockers, 9-anthracene carboxylic acid and niflumic acid, upon the ionic currents of oocytes of the South American toad Bufo arenarum. The main results were: (1) both blockers produced a reversible increase of the outward currents on a dose-dependent manner; (2) the activated outward current was voltage dependent; (3) the 9-anthracene carboxylic acid-sensitive current was blocked with barium; and (4) the effect of 9-anthracene carboxylic acid was more pronounced in a zero-K(+) solution than in standard (2 mmol l(-1)) or high (20 mmol l(-1)) K(+) solutions, indicating that a K(+) conductance is activated. The effect of the Cl(-) channel blockers could be due to a direct interaction with endogenous cationic channels. Another possible explanation is that Cl(-) that enter the cell during depolarizing steps in control solution inhibit this cationic conductance; thus, the blockade of Cl(-) channels by 9-anthracene carboxylic acid and niflumic acid would remove this inhibition, allowing the cationic current to flow freely.

Biological response to climate change on a tropical mountain

NASA Astrophysics Data System (ADS)

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

1999-04-01

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

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

PubMed

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

2016-01-01

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

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

PubMed Central

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

2016-01-01

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

Changes in the antioxidant metabolism in the embryonic development of the common South American toad Bufo arenarum: differential responses to pesticide in early embryos and autonomous-feeding larvae.

PubMed

Ferrari, Ana; Anguiano, Liliana; Lascano, Cecilia; Sotomayor, Verónica; Rosenbaum, Enrique; Venturino, Andrés

2008-01-01

Amphibians may be critically challenged by aquatic contaminants during their embryonic development. Many classes of compounds, including organophosphorus pesticides, are able to cause oxidative stress that affects the delicate cellular redox balance regulating tissue modeling. We determined the progression of antioxidant defenses during the embryonic development of the South American common toad, Bufo arenarum. Superoxide dismutase (SOD) and catalase (CAT) activities were high in the unfertilized eggs, and remained constant during the first stages of development. SOD showed a significant increase when the gills were completely active and opercular folds began to form. Reductase (GR) activity was low in the oocytes and increased significantly when gills and mouth were entirely developed and the embryos presented a higher exposure to pro-oxidant conditions suggesting an environmental control. Reduced glutathione (GSH) content was also initially low, and rose continuously pointing out an increasing participation of GSH-related enzymes in the control of oxidative stress. GSH peroxidases and GSH-S-transferases showed relatively high and constant activities, probably related to lipid peroxide control. B. arenarum embryos have plenty of yolk platelets containing lipids, which provide the energy and are actively transferred to the newly synthesized membranes during the early embryonic development. Exposure to the pro-oxidant pesticide malathion during 48 h did not significantly affect the activity of antioxidant enzymes in early embryos, but decreased the activities of CAT, GR, and the pool of GSH in larvae. Previous work indicated that lipid peroxide levels were kept low in malathion-exposed larvae, thus we conclude that oxidative stress is overcome by the antioxidant defenses. The increase in the antioxidant metabolism observed in the posthatching phase of development of B. arenarum embryo, thus constitutes a defense against natural and human-generated pro

Mortality and toxin bioaccumulation in Bufo marinus following exposure to Cylindrospermopsis raciborskii cell extracts and live cultures.

PubMed

White, S H; Duivenvoorden, L J; Fabbro, L D; Eaglesham, G K

2007-05-01

Cylindrospermopsis raciborskii is a cyanobacterium responsible for the production of the toxin, cylindrospermopsin (CYN). Tadpoles of the cane toad Bufo marinus were exposed to freeze-thawed whole cell extracts or live cultures of C. raciborskii containing maximum CYN concentrations of 400 microg L-1 or 232 microg L-1, respectively. Exposure to live culture treatment solutions resulted in up to 66% mortality of B. marinus, whereas tadpoles exposed to whole cell extracts containing similar toxin concentrations survived. Decreases in relative growth rates and time spent for swimming were recorded from tadpoles during both types of exposure regimes. Bioconcentration of CYN was not evident following exposure to whole cell extracts containing extracellular toxin. In contrast exposure to live cultures, which contained cell-bound toxin, resulted in maximum average tissue concentrations of 895 microg free-CYN kg-1 fresh weight. This is the first investigation of C. raciborskii exposure effects and toxin bioaccumulation in the developmental stages of an amphibian.

Counterbalancing effects of maternal mercury exposure during different stages of early ontogeny in American toads.

PubMed

Bergeron, Christine M; Hopkins, William A; Bodinof, Catherine M; Budischak, Sarah A; Wada, Haruka; Unrine, Jason M

2011-10-15

Maternal transfer of environmental contaminants is a disadvantageous parental effect which can have long-lasting implications for offspring fitness. We investigated the effects of mercury (Hg) on the reproductive success of female amphibians and the subsequent effects of maternal transfer on the development of their offspring. American toads (Bufo americanus) maternally transferred Hg to their eggs, and there was a negative relationship between Hg concentrations and the percentage of viable hatchlings produced in clutches. However, when we continued to monitor larvae that successfully hatched, we found 21% greater metamorphic success in larvae from Hg-exposed mothers compared to reference larvae. The negative effect in the embryonic stage and positive effect in the larval stage counterbalanced one another, ultimately resulting in no difference in predicted terrestrial recruitment, regardless of maternal Hg exposure. Our findings demonstrate that maternal effects on survival manifesting at different stages in ontogeny have the potential to produce complicated outcomes. Copyright © 2011 Elsevier B.V. All rights reserved.

Seasonal changes in the activity of cytochrome P450(C17) from the testis of Bufo arenarum.

PubMed

Solari, J J F; Pozzi, A G; Ceballos, N R

2002-12-01

In Bufo arenarum, the biosynthesis of testosterone and 5alpha-dihydrotestosterone takes place through a complete 5-ene pathway, 5-androsten-3beta,17beta-diol being the immediate precursor of testosterone. Besides androgens, testes are able to synthesise 5alpha-pregnan-3,20-dione and several 3alpha and 20alpha reduced derivatives. During the breeding season, steroid biosynthesis turns from androgen to C21-steroid production. As a consequence, the cytochrome P450 17-hydroxylase, C17,20-lyase (CypP450(c17)) could be a key enzyme in that metabolic shift. The present study demonstrates that in testes of B. arenarum, CypP450(c17) co-localises with glucose-6-phosphatase in the microsomal fraction. CypP450(c17) possesses more affinity for pregnenolone than for progesterone in both non-reproductive (Km = 43.76 +/- 4.63 nM and 2,170 +/- 630 nM, respectively) and reproductive (Km = 37.46 +/- 4.19 nM and 3,060 +/- 190 nM, respectively) seasons. These results could explain the predominance of the 5-ene pathway for testosterone biosynthesis. Toad CypP450(c17) activity is higher in the non-reproductive period than the reproductive period, suggesting that this enzyme is an important factor in toad steroidogenic changes. Animals in reproductive conditions showed a significant reduction in circulating androgens. This is in agreement with the decrease in Vmax of cytochrome P450 17-hydroxylase activity, enhancing the physiological relevance of these in vitro results.

RADIATION AND OTHER FACTORS INFLUENCING THE DISTRIBUTION OF ANIMALS. Progress Report and Renewal Proposal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Breckenridge, W.J.; Tester, J.R.

1962-01-01

Progress is reported for studies of environmental and radiation effects on three species of toads, Bufo americanus, B. cognatus and B. hemiophrys. Controlled surival tests in which tadpoles of B. americanus and B. hemiophrys were subjected to physical and chemical extremes indicated that B. hemiophrys is more resistant than B. americanus. The status of the subprojects on factors influencing toad survival during hibernatlon and irradistion of dormant toads is outlined. A soil simulator was built for studying the burrowing behavior of toads. (D.L.C.)

76 FR 46837 - Endangered and Threatened Species Permit Applications

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-03

...). Houston toad (Bufo houstonensis). Barton Springs salamander (Eurycea sosorum). San Marco salamander (Eurycea nana). Texas blind salamander (Typhlomolge rathbuni). Fountain darter (Etheostoma fonticola). Two...

Within- and among-population level differences in response to chronic copper exposure in southern toads, Anaxyrus terrestris.

PubMed

Lance, Stacey L; Flynn, R Wesley; Erickson, Matthew R; Scott, David E

2013-06-01

Environmental contaminants are implicated in the global decline of amphibian populations. Copper (Cu) is a widespread contaminant that can be toxic at concentrations just above the normal physiological range. In the present study we examined the effects of chronic Cu aqueous exposure on embryos and larvae of southern toads, Anaxyrus (Bufo) terrestris. Measurable levels of Cu were found in larvae, with tissue concentrations up to 27.5 μg Cu/g dry mass. Aqueous concentrations of Cu as low as 10 μg/L significantly reduced survival to the free-swimming stage and no larvae reached metamorphosis at concentrations above 15 μg/L. Clutches from populations with prior Cu exposure had the lowest survivorship. Among several populations there was significant variation in survivorship at different levels of Cu. More data are needed to understand the underlying causes of within- and among-population resilience to anthropogenic stressors. Copyright © 2013 Elsevier Ltd. All rights reserved.

Some aspects of the inhibition of the action of antidiuretic hormone by lithium ions in the rat kidney and bladder of the toad Bufo marinus

PubMed Central

Harris, Carol A.; Jenner, F. A.

1972-01-01

1. The effect of intravenous infusions of various ions on the antidiuretic action of antidiuretic hormone has been studied in rats. 2. Lithium (13 mmol/l.) reversibly inhibits the antidiuretic responses. Similar concentrations of potassium, rubidium, strontium, magnesium, choline and calcium do not. Lithium has a similar effect on the antidiuretic activity of oxytocin. 3. The inhibition is not simply related to blood nor whole body lithium concentrations. 4. Lithium (2 mmol/l.) in contact with the serosal surface also inhibits the transport of water facilitated by either 0·5 U/l. antidiuretic hormone or 1·1 mmol/l. cyclic adenosine monophosphate in the isolated toad bladder. 5. Choline (2 mmol/l.) on the serosal surface also inhibits the transport of water facilitated by vasopressin in the toad bladder. PMID:4358411

[The effects of anterio-posterior and dorso-ventral inversions of the lateral mesoblast of the neurula on the formation of the mesonephric, medullary, and adrenal anlage of the common toad, Bufo bufo L. (Amphibia, Anoura)].

PubMed

Gipouloux, J D; Hakim, J

1975-10-13

The experimental results of cranio-caudal reversal and dorso-ventral reversal of the lateral mesoblast of the toad early neurula prove that, at this stage, the cranio-caudal polarity of this tissue is fixed but not the dorso-ventral one. External factors are responsible for the formation of mesonephric, adrenal and gonadal medullary anlage by the lateral mesoblast.

Population genetic structure and disease in montane boreal toads: More heterozygous individuals are more likely to be infected with amphibian chytrid

USGS Publications Warehouse

Addis, Brett; Lowe, Winsor; Hossack, Blake R.; Allendorf, Fred

2015-01-01

Amphibians are more threatened than any other vertebrate group, with 41 % of species classified as threatened. The causes of most declines are not well understood, though many declines have been linked to disease. Additionally, amphibians are physiologically constrained to moist habitats and considered poor dispersers; thus, they may suffer genetic consequences of population isolation. To understand threats to the persistence of boreal toads (Bufo boreas) in Glacier National Park, USA, we genotyped 551 individuals at 11 microsatellite loci and used Bayesian clustering methods to describe population genetic structure and identify barriers to gene flow. We found evidence of two primary genetic groups that differed substantially in elevation and two secondary groups within the high elevation group. There was also evidence of further substructure within the southern high elevation group, suggesting mountain ridges are barriers to gene flow at local scales. Overall, genetic variation was high, but allelic richness declined with increasing elevation, reflecting greater isolation or smaller effective population sizes of high altitude populations. We tested for Batrachochytrium dendrobatidis (Bd), the fungal pathogen which causes chytridiomycosis, and we found that 35 of 199 toads were positive for Bd. Unexpectedly, more heterozygous individuals were more likely to be infected. This suggests that dispersal facilitates the spread of disease because heterozygosity may be highest where dispersal and gene flow are greatest.

Oxidative stress, endocrine disruption, and malformation of Bufo gargarizans embryo exposed to sub-lethal cadmium concentrations.

PubMed

Wu, Chao; Zhang, Yuhui; Chai, Lihong; Wang, Hongyuan

2017-01-01

Thyroid hormone (TH) is critical for vertebrate postembryonic development as well as embryonic development. Chinese toad (Bufo gargarizans) embryos were exposed to different concentrations of cadmium (5, 50, 100, 200 and 500μg Cd L -1 ) for 7days. Malformations were monitored daily, and growth and development of embryos were measured at day 4 and 7, and type 2 and 3 iodothyronine deiodinase (Dio2 and Dio3), thyroid hormone receptors (TRα and TRβ) mRNA levels were also measured to assess disruption of TH synthesis. In addition, superoxide dismutase (SOD), glutathione peroxidase (GPx) and heat shock proteins (HSPs) mRNA expression were examined to evaluate the ability of scavenging ROS. Our results demonstrated a bimodal inhibitory effect of Cd on the embryo growth and development of Bufo gargarizans. Reduced mean stage, total length and weight were observed at 5, 50, 200 and 500, but not at 100μg Cd L -1 . Embryos malformation occurred in all cadmium treatments. Morphological abnormalities of embryos are characterized by axial flexures, abdominal edema, stunted growth and fin flexure. Real-time PCR results show that exposure to cadmium down-regulated TRα and Dio3 mRNA expression and up-regulated Dio2 mRNA level. SOD and GPx mRNA expression was significantly up-regulated after cadmium exposure. We concluded that cadmium could change mRNA expression of TRα, Dio2 and Dio3 leading the inhibition of growth and development of B. gargarizans embryo, which suggests that cadmium might have the endocrine-disrupting effect in embryos. Moreover, the reduced ability of scavenging ROS induced by cadmium might be responsible for the teratogenic effects of cadmium. Copyright © 2016 Elsevier B.V. All rights reserved.

Positive lusitropic effect and diminished myofibrillar sensitivity to calcium produced by cAMP on toad (Bufo arenarum Hensel) ventricle.

PubMed

Vila Petroff, M; Vittone, L; Mundiña, C; Chiappe de Cingolani, G; Alicia, M

1992-01-01

In intact ventricular strips from toad heart, we studied the relaxant or positive lusitropic effect of different interventions known to increase intracellular cAMP levels. Isoproterenol increased developed tension (DT), maximal rate of contraction (+T), and maximal velocity of relaxation (-T). From 10(-8) to 10(-4)M isoproterenol, -T increased proportionally more than +T being the ratio +T/-T significantly decreased. A single dose of isoproterenol (3 x 10(-8)M) increased cAMP levels from 0.174 +/- 0.022 to 0.329 +/- 0.039 pmoles/mg ww (P < 0.05), increased contractility by 69 +/- 13% and decreased +T/-T by 18.5 +/- 4.55%. Administration of 10(-3)M of dibutyryl cyclic AMP (dcAMP) significantly increased DT and +T and decreased the ratio +T/-T. Similar effects were obtained with milrinone, a specific cAMP phosphodiesterase inhibitor. Papaverine, a non selective phosphodiesterase inhibitor, failed to increase +T but significantly increased -T. In chemically skinned ventricular trabeculae, calcium sensitivity of the myofibrils was significantly increased by 10(-5)M of the phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine (IBMX). 10(-3)M dcAMP failed to affect calcium sensitivity of chemically skinned ventricular trabeculae when given alone, but produced a decrease in calcium sensitivity of the myofibrils in the presence of 10(-5)M of either IBMX or papaverine. The results would indicate that the relaxant effect of isoproterenol is mediated in toad ventricle by an increase in intracellular cAMP levels. They furthermore suggest that a decrease in myofilament sensitivity to calcium may be a mechanism by which cAMP produces its relaxant effect.

Potential, Current, and Ionic Fluxes across the Isolated Retinal Pigment Epithelium and Choroid

PubMed Central

Lasansky, Arnaldo; de Fisch, Felisa W.

1966-01-01

A flux chamber was utilized for in vitro studies of a membrane formed by the retinal pigment epithelium and choroid of the eye of the toad (Bufo arenarum and Bufo marinus). A transmembrane potential of 20 to 30 mv was found, the pigment epithelium surface positive with respect to the choroidal surface. Unidirectional fluxes of chloride, sodium, potassium, and calcium were determined in the absence of an electrochemical potential difference. A net transfer of chloride from pigment epithelium to choroid accounted for a major fraction of the mean short-circuit current. A small net flux of sodium from choroid to pigment epithelium was detected in Bufo marinus. In both species of toads, however, about one-third of the mean short-circuit current remained unaccounted for. Manometric determinations of bicarbonate suggested an uptake of this ion at the epithelial surface of the membrane but did not provide evidence of a relationship between this process and the short-circuit current. PMID:5961357

Historical biogeography resolves the origins of endemic Arabian toad lineages (Anura: Bufonidae): Evidence for ancient vicariance and dispersal events with the Horn of Africa and South Asia.

PubMed

Portik, Daniel M; Papenfuss, Theodore J

2015-08-06

The Arabian Peninsula is home to a unique fauna that has assembled and evolved throughout the course of major geophysical events, including the separation of the Arabian Plate from Africa and subsequent collision with Eurasia. Opportunities for faunal exchanges with particular continents occurred in temporally distinct periods, and the presence of African, Western Eurasian, and South Asian derived taxa on the Arabian Peninsula signifies the complexity of these historical biogeographic events. The six true toad species (family Bufonidae) endemic to Arabian Peninsula present a considerable taxonomic and biogeographic challenge because they are part of a global bufonid radiation, including several genera surrounding the Arabian Peninsula, and difficult to discriminate morphologically. As they could be derived from African, Western Eurasian, or South Asian toad groups, elucidating their evolutionary relationships has important implications for historical biogeography. Here, we analyze a global molecular data set of 243 bufonid lineages, with an emphasis on new sampling from the Horn of Africa, Western Eurasia, South Asia, and the Arabian Peninsula, to reconstruct the evolutionary relationships of the Arabian species. We produce a robust time-calibrated phylogeny to infer the biogeographic history of this group on and around the Arabian Peninsula. Our phylogenetic analyses indicate two of the endemic Arabian toad species, "Bufo" tihamicus and "Bufo" arabicus, evolved independently within the African genus Amietophrynus. We confirm the Arabian species Duttaphrynus dhufarensis is of South Asian origin, but do not find evidence for the Asian genus Duttaphrynus being present in the Horn of Africa, discrediting a previously proposed Asian bufonid dispersal event to Africa. We also do not find evidence of the African genus Amietophrynus occurring in South Asia, suggesting that unlike many other vertebrate taxa, toads have not used the Arabian Peninsula as a stepping-stone for

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

PubMed

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

2012-10-15

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rapoport, J.; Abuful, A.; Chaimovitz, C.

Urea is actively transported inwardly (J{sub i}) across the skin of the green toad Bufo viridis. J{sub i} is markedly enhanced in toads adapted to hypertonic saline. The authors studied urea transport across the skin of Bufo viridis under a variety of experimental conditions, including treatment with amiloride and phloretin, agents that inhibit urea permeability in the bladder of Bufo marinus. Amiloride (10{sup {minus}4} M) significantly inhibited J{sub i} in both adapted and unadapted animals and was unaffected by removal of sodium from the external medium. Phloretin (10{sup {minus}4} M) significantly inhibited J{sub i} in adapted animals by 23-46%; theremore » was also a reduction in J{sub i} in unadapted toads at 10{sup {minus}4} and 5 {times} 10{sup {minus}4} M phloretin. A dose-response study revealed that the concentration of phloretin causing half-maximal inhibition (K{sub {1/2}}) was 5 {times} 10{sup {minus}4} M for adapted animals. J{sub i} was unaffected by the substitution of sucrose for Ringer solution or by ouabain. They conclude (1) the process of adaptation appears to involve an increase in the number of amiloride- and phloretin-inhibitable urea transport sites in the skin, with a possible increase in the affinity of the sites for phloretin; (2) the adapted skin resembles the Bufo marinus urinary bladder with respect to amiloride and phloretin-inhibitable sites; (3) they confirm earlier observations that J{sub i} is independent of sodium transport.« less

Endothelial cells in the oral mucosa of Bufo marinus.

PubMed Central

Loo, S K; Yeo, B C; Kovac, H

1980-01-01

The oral mucosa of the cane toad (Bufo marinus) is lined by a pseudostratified columnar ciliated epithelium containing an intraepithelial network of capillaries, which penetrates it to the bases of the distal layer of cells. The capillaries are lined by fenestrated endothelium lying on a complete basal lamina. A connective tissue sheath, approximately 1 micrometer thick, surrounds the capillaries and separates them from the surrounding epithelial cells. Endothelial cells resemble those in lymphatic capillaries in that they show microvillus-like processes or folds projecting into the lumen and also have extremely attenuated and fenestrated cytoplasm except in the nuclear region. Numerous pinocytotic vesicles, bundles of filaments and many electrondense granules occur in the cytoplasm. These granules are oval or round in shape and approximately 250-400 micrometer in diameter. Histochemical tests on the endothelial cells show that the granules do not contain pigment, as both the Schmorl and argentaffin reactions are negative. Both the Sudan black B and Luxol fast blue reactions are also negative showing the lack of stainable lipids. The formaldehyde-induced fluorescence, the argentaffin reactions and lead haematoxylin reactions are negative, indicating that they do not have the characteristics of endocrine cells. The acid phosphatase reaction gives a positive result, localized to the site of the granules by electron microscopy and suggesting that these granules in amphibian capillaries may have a lysosomal function. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 PMID:6773911

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

USGS Publications Warehouse

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

2000-01-01

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

Egg water from the amphibian Bufo arenarum induces capacitation-like changes in homologous spermatozoa.

PubMed

Krapf, Darío; Visconti, Pablo E; Arranz, Silvia E; Cabada, Marcelo O

2007-06-15

Mammalian sperm acquire fertilizing capacity after residing in the female tract, where physiological changes named capacitation take place. In animals with external fertilization as amphibians, gamete interactions are first established between sperm and molecules of the egg jelly coat released into the medium. Since dejellied oocytes are not normally fertilized, the aim of this study was to determine if the jelly coat of the toad Bufo arenarum promotes a "capacitating" activity on homologous sperm. We found that sperm incubation in diffusible substances of the jelly coat (egg water) for 90-180 s is sufficient to render sperm transiently capable of fertilizing dejellied oocytes. The fertilizing state was correlated with an increase of protein tyrosine phosphorylation and a decrease of sperm cholesterol content. Inhibition of either the increase in tyrosine phosphorylation or cholesterol efflux affected the acquisition of fertilizing capacity. Phosphorylation and fertilization could be promoted with NaHCO(3) and also by addition of beta cyclodextrin. Moreover, sperm could gain the ability to fertilize dejellied oocytes in the presence of these compounds. These data indicate that sperm should undergo a series of molecular changes to gain fertilizing capacity; these changes are reminiscent of mammalian sperm capacitation and take place before the acrosome reaction.

Egg water from the amphibian Bufo arenarum induces capacitation-like changes in homologous spermatozoa

PubMed Central

Krapf, Darío; Visconti, Pablo E.; Arranz, Silvia E; Cabada, Marcelo O

2007-01-01

Mammalian sperm acquire fertilizing capacity after residing in the female tract, where physiological changes named capacitation take place. In animals with external fertilization as amphibians, gamete interactions are first established between sperm and molecules of the egg jelly coat released into the medium. Since dejellied oocytes are not normally fertilized, the aim of this study was to determine if the jelly coat of the toad Bufo arenarum promotes a “capacitating” activity on homologous sperm. We found that sperm incubation in diffusible substances of the jelly coat (Egg Water) for 90–180 sec is sufficient to render sperm transiently capable of fertilizing dejellied oocytes. The fertilizing state was correlated with an increase of protein tyrosine phosphorylation and a decrease of sperm cholesterol content. Inhibition of either the increase in tyrosine phosphorylation or cholesterol efflux affected the acquisition of fertilizing capacity. Phosphorylation and fertilization could be promoted with NaHCO3, and also by addition of beta cyclodextrin. Moreover, sperm could gain the ability to fertilize dejellied oocytes in the presence of these compounds. These data indicate that sperm should undergo a series of molecular changes to gain fertilizing capacity; these changes are reminiscent of mammalian sperm capacitation and take place before the acrosome reaction. PMID:17459363

pH and rate of ‘dark’ events in toad retinal rods: test of a hypothesis on the molecular origin of photoreceptor noise

PubMed Central

Firsov, Mikhail L; Donner, Kristian; Govardovskii, Victor I

2002-01-01

Thermal activation of the visual pigment constitutes a fundamental constraint on visual sensitivity. Its electrical correlate in the membrane current of dark-adapted rods are randomly occurring discrete ‘dark events’ indistinguishable from responses to single photons. It has been proposed that thermal activation occurs in a small subpopulation of rhodopsin molecules where the Schiff base linking the chromophore to the protein part is unprotonated. On this hypothesis, rates of thermal activation should increase strongly with rising pH. The hypothesis has been tested by measuring the effect of pH changes on the frequency of discrete dark events in red rods of the common toad Bufo bufo. Dark noise was recorded from isolated rods using the suction pipette technique. Changes in cytoplasmic pH upon manipulations of extracellular pH were quantified by measuring, using fast single-cell microspectrophotometry, the pH-dependent metarhodopsin I-metarhodopsin II equilibrium and subsequent metarhodopsin III formation. These measurements show that, in the conditions of the electrophysiological experiments, changing perfusion pH from 6.5 to 9.3 resulted in a cytoplasmic pH shift from 7.6 to 8.5 that was readily sensed by the rhodopsin. This shift, which implies an 8-fold decrease in cytoplasmic [H+], did not increase the rate of dark events. The results contradict the hypothesis that thermal pigment activation depends on prior deprotonation of the Schiff base. PMID:11897853

Altitudinal variation of demographic life-history traits does not mimic latitudinal variation in natterjack toads (Bufo calamita).

PubMed

Oromi, Neus; Sanuy, Delfi; Sinsch, Ulrich

2012-02-01

In anuran amphibians, age- and size-related life-history traits vary along latitudinal and altiudinal gradients. In the present study, we tested the hypothesis that altitudinal and latitudinal effects cause similar responses by assessing demographic life-history traits in nine Bufo calamita populations inhabiting elevations from sea level to 2270 m. Skeletochronologically determined age at maturity and longevity increased at elevations exceeding 2000 m, but female potential reproductive lifespan (PRLS) did not increase with altitude, as it did with latitude. Integrating the available evidence, it was found that lifetime fecundity of natterjacks decreased at the upper altitudinal range because PRLS was about the same as in lowland populations but females were smaller. In contrast, small size of northern females was compensated for by increased PRLS which minimised latitudinal variation of lifetime fecundity. Thus, this study provides evidence that altitudinal effects on life-history traits do not mimic latitudinal effects. Life-history trait variation along the altitudinal gradient seems to respond directly to the shortening of the annual activity period. As there is no evidence for increasing mortality in highland populations, reduced lifetime fecundity may be the ultimate reason for the natterjacks' inability to colonise elevations exceeding 2500 m. Copyright © 2011 Elsevier GmbH. All rights reserved.

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

PubMed

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

2012-10-01

The influence of landscape matrix on functional connectivity has been clearly established. Now methods to assess the effects of different land uses on species' movements are needed because current methods are often biased. The use of physiological parameters as indicators of the level of resistance to animal movement associated with different land uses (i.e., matrix resistance) could provide estimates of energetic costs and risks to animals migrating through the matrix. To assess whether corticosterone levels indicate matrix resistance, we conducted experiments on substrate choice and measured levels of corticosterone before and after exposure of toads (Bufo bufo) to 3 common substrates (ploughed soil, meadow, and forest litter). We expected matrix resistance and hormone levels to increase from forest litter (habitat of the toad) to meadows to ploughed soil. Adult toads had higher corticosterone levels on ploughed soil than on forest litter or meadow substrates. Hormone levels did not differ between forest litter and meadow. Toads avoided moving onto ploughed soil. Corticosterone levels in juvenile toads were not related to substrate type; however, hormone levels decreased as humidity increased. Juveniles, unlike adults, did not avoid moving over ploughed soil. The difference in responses between adult and juvenile toads may have been due to differences in experimental design (for juveniles, entire body used to measure corticosterone concentration; for adults, saliva alone); differences in the scale of sensory perception of the substrate (juveniles are much smaller than adults); or differences in cognitive processes between adult and juvenile toads. Adults probably had experience with different substrate types, whereas juveniles first emerging from the water probably did not. As a consequence, arable lands could act as ecological traps for juvenile toads. ©2012 Society for Conservation Biology.

Structure of the kidney of Bufo arenarum: intermediate segment, distal tubule and collecting tubule.

PubMed

Farías, Alejandro; Hermida, Gladys Noemí; Fiorito, Luisa Eleonora

2003-04-01

The ultrastructure of the intermediate segment (IS), distal tubule and collecting tubule (CT) of the south american toad Bufo arenarum, was studied by light and transmission electron microscopy. The IS is composed of cubical ciliated cells which propel the urine along the renal tubule. The distal tubule is divided into two portions: the early distal tubule (EDT) and the late distal tubule (LDT). The EDT is characterized by only one type of cells with well developed basolateral interdigitations and numerous elongated mitochondria, which are oriented normal to the basal surface. The "macula densa--like" is a specialized zone of the EDT in contact with the vascular pole, where cells are more tightly packed than in the rest of the tubule. The LDT shows two types of cells called dark and light cells according to the appearance of their cytoplasm. Dark cells have microplicae and few but long microvilli at their luminal surface, and abundant mitochondria in their cytoplasm. Light cells show basal and lateral infoldings and few mitochondria. The CT, which is composed of dark and light cells, exhibits an enlarged lumen with an undulated surface and dilated spaces between neighbouring cells. This work is a contribution to the knowledge of the kidney of B. arenarum; frequently used as an experimental model for physiological and biochemical studies.

Environmental Assessment of Construction of a Security Perimeter Road and Fence at Grand Forks AFB, North Dakota

DTIC Science & Technology

2005-04-01

Mountain juniper (Juniperus scopulorum), laurel leaf willow (Salix pentandra), Japanese lilac tree (Syringa reticulata), Amur chokecherry (Prunus maackii...Western painted turtle (Chrysemys picta belli), Northern leopard frog (Rana pipiens), Western chorus frog (Pseudacris triseriata), American toad (Bufo

Optical, Biochemical, and Molecular Characterization of New Bioluminescence Systems

DTIC Science & Technology

2007-05-09

5cym 5 * Hutioti Annid Polythasta SprinostunthstinosjtnImons + mouth Sou Annelid. - Polyoheete Stats W.nm ++ Itnoen + At 493-5946 616 -664 - 719...biranhunnsi + lhite) +7 mouth fl o Coýi~ca-5eat:m’ptda: - Limpet Ceguthtn. oneuista A Isnoon/blatcl, + Plate ot manatle 572 616-664- 719 Coisc- "tnpda...as an aposematic signal upon toads (Bufo bufo). Behav. 3! Ecol. 2003; 14: 103-108. 6. Baker, CH. Dipterian glow-worms: marvelous maggots weave magic

The effects of fasting and cold exposure on metabolic rate and mitochondrial proton leak in liver and skeletal muscle of an amphibian, the cane toad Bufo marinus.

PubMed

Trzcionka, M; Withers, K W; Klingenspor, M; Jastroch, M

2008-06-01

Futile cycling of protons across the mitochondrial inner membrane contributes significantly to standard metabolic rate in a variety of ectothermic and endothermic animals, but adaptations of the mitochondrial bioenergetics to different environmental conditions have rarely been studied in ectotherms. Changes in ambient temperature and nutritional status have a great effect on the physiological demands of ectothermic amphibians and may require the adjustment of mitochondrial efficiency. In order to investigate the effect of temperature and nutritional status on the mitochondrial level, we exposed male cane toads to either 10 degrees C or 30 degrees C and fasted half of the animals in each group. Cold exposure resulted in a fourfold reduction of the resting metabolic rate whereas nutritional status had only minor effects. The mitochondrial adjustments to each condition were observed by comparing the proton leak kinetics of isolated liver and skeletal muscle mitochondria at 25 degrees C. In response to cold exposure, liver mitochondria showed a decrease in proton conductance while skeletal muscle mitochondria were unchanged. Additional food deprivation had minor effects in skeletal muscle, but in liver we uncovered surprising differences in energy saving mechanisms between the acclimation temperatures: in warm-acclimated toads, fasting resulted in a decrease of the proton conductance whereas in cold-acclimated toads, the activity of the respiratory chain was reduced. To investigate the molecular mechanism underlying mitochondrial proton leakage, we determined the adenine-nucleotide transporter (ANT) content, which explained tissue-specific differences in the basal proton leak, but neither the ANT nor uncoupling protein (UCP) gene expression correlated with alterations of the proton leak in response to physiological stimuli.

Transcriptomics provides mechanistic indicators of fluoride toxicology on endochondral ossification in the hind limb of Bufo gargarizans.

PubMed

Chao, Wu; Zhang, Yuhui; Chai, Lihong; Wang, Hongyuan

2018-06-10

Endochondral ossification, the process by which most of the bone is formed, is regulated by many specific groups of molecules and extracellular matrix components. Hind limb of Bufo gargarizans is a model to study endochondral ossification during metamorphosis. Chinese toad (Bufo gargarizans) were exposed to different fluoride concentrations (0, 1, 5, 10 and 20 mg L -1 ) from G3 to G42. The development of hind limb of B. gargarizans was observed using the double staining methodology. The transcriptome of hind limb of B. gargarizans was conducted using RNA-seq approach, and differentially expressed gene was also validated. In addition, the location of Sox9 and Ihh in the growth cartilage was determined using in situ hybridization. Our results showed that 5 mg L -1 stimulated bone mineralization, while 10 and 20 mg L -1 exposure could inhibit the tibio-fibula, tarsus and metacarpals ossification. Besides, 10 mg F/L treatment could down-regulate Ihh, Sox9, D2, D3, TRα, TRβ, Wnt10, FGF3 and BMP6 expression, while up-regulate ObRb and HHAT mRNA expression in the hind limb of B. gargarizans. Transcript level changes of Ihh, Sox9, D2, D3, TRα, TRβ, Wnt10, FGF3 and BMP6 were consistent with the results of RT-qPCR. In situ hybridization revealed that Ihh was expressed in prehypertrophic chondrocytes, while Sox9 was abundantly expressed in proliferous, prehypertrophic and hypertrophic chondrocytes. However, 10 mg F-/L did not cause any affect in the location of the Ihh and Sox9 mRNA. Therefore, high concentration of fluoride could affect the ossification-related genes mRNA expression and then inhibit the endochondral ossification. The present study thus will greatly contribute to our understanding of the effect of environmental contaminant on ossification in amphibian. Copyright © 2018 Elsevier B.V. All rights reserved.

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

PubMed

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

2016-01-01

Chinese toad (Bufo gargarizans) tadpoles were exposed to copper (1, 6.4, 32 and 64μgL(-1) copper) from the beginning of larval period through completion of metamorphosis. We examined the effects of chronic copper exposure on mortality, growth, time to metamorphosis, tail resorption time, body size at the metamorphic climax (Gs 42) and completion of metamorphosis (Gs 46) and thyroid gland histology. In addition, type 2 and 3 iodothyronine deiodinase (Dio2 and Dio3), thyroid hormone receptors (TRα and TRβ) mRNA levels were also measured to assess disruption of TH synthesis. Our result showed that 6.4-64μgL(-1) copper concentration increased the mortality and inhibited the growth of B. gargarizans tadpoles. In addition, significant reduction in size at Gs 42 and a time delay to Gs 42 were observed at 6.4-64μgL(-1) copper treatments. Moreover, histological examinations have clearly revealed that 64μgL(-1) copper caused follicular cell hyperplasia in thyroid gland. According to real-time PCR results, exposure to 32 and 64μgL(-1) copper significantly up-regulated mRNA expression of Dio3, but down-regulated mRNA expression of TRα and TRβ mRNA level. We concluded that copper delayed amphibian metamorphosis through changing mRNA expression of Dio3, TRα and TRβ, which suggests that copper might have the endocrine-disrupting effect. Copyright © 2015 Elsevier B.V. All rights reserved.

The impact of invasive cane toads on native wildlife in southern Australia.

PubMed

Jolly, Christopher J; Shine, Richard; Greenlees, Matthew J

2015-09-01

Commonly, invaders have different impacts in different places. The spread of cane toads (Rhinella marina: Bufonidae) has been devastating for native fauna in tropical Australia, but the toads' impact remains unstudied in temperate-zone Australia. We surveyed habitat characteristics and fauna in campgrounds along the central eastern coast of Australia, in eight sites that have been colonized by cane toads and another eight that have not. The presence of cane toads was associated with lower faunal abundance and species richness, and a difference in species composition. Populations of three species of large lizards (land mullets Bellatorias major, eastern water dragons Intellagama lesueurii, and lace monitors Varanus varius) and a snake (red-bellied blacksnake Pseudechis porphyriacus) were lower (by 84 to 100%) in areas with toads. The scarcity of scavenging lace monitors in toad-invaded areas translated into a 52% decrease in rates of carrion removal (based on camera traps at bait stations) and an increase (by 61%) in numbers of brush turkeys (Alectura lathami). The invasion of cane toads through temperate-zone Australia appears to have reduced populations of at least four anurophagous predators, facilitated other taxa, and decreased rates of scavenging. Our data identify a paradox: The impacts of cane toads are at least as devastating in southern Australia as in the tropics, yet we know far more about toad invasion in the sparsely populated wilderness areas of tropical Australia than in the densely populated southeastern seaboard.

Long-term heavy metal pollution varied female reproduction investment in free-living anura, Bufo raddei.

PubMed

Zhang, Wenya; Guo, Rui; Ai, Shiwei; Yang, Ying; Ding, Jian; Zhang, Yingmei

2018-09-15

Environment contamination is known to affect the growth, reproduction, and even mortality of anuran species, and hence modulate their life history traits. Although knowledge of the ability of amphibians to cope with harsh environments has gained ongoing research, the reproductive strategy of free-living amphibians subjected to long-term heavy metal pollution is largely unknown. This study aimed to explore the variation in the life history traits, including age structure, maturation age, reproductive investment, and reproduction trade-off, in female Bufo raddei, a widespread anuran in Baiyin (BY) in northwest of China, subjected to sublethal heavy metal pollution. B. raddei collected from Liujiaxia (LJX), a relatively unpolluted area, were used as control. Skeletochronological analysis revealed variation in the average breeding age of females: more than 70% of females from BY began to breed 1 year before the toads collected from LJX. Females from BY tended to prioritize reproduction over survival and invested more in their first reproductive event. Further, females in BY with a high fluctuating asymmetry index showed a relatively lower reproductive investment. For trade-off in offspring number and size, BY population optimize larger clutch sizes with smaller egg size compared with population in LJX. Changes in female reproductive investment caused by heavy metal pollution might ultimately alter the structural stability of amphibian population. Copyright © 2018 Elsevier Inc. All rights reserved.

Herpetofaunal species composition and relative abundance among three New England forest types

Treesearch

Richard M. DeGraaf; Deborah D. Rudis

1990-01-01

Drift fences and pitfall traps captured > 2000 reptiles and amphibians during 2 years; the most common species were wood frog (Rana sylvatica), American toad (Bufo americanus), and redback salamander (Plethodon cinereus). There were differences in species abundances among streamside and upland...

Shock characterization of toad pins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weirick, L.J.; Navarro, M.J.

1996-05-01

The purpose of this program was to characterize Time Of Arrival Detectors (TOAD) pins response to shock loading with respect to risetime, amplitude, repeatability and consistency. TOAD pins were subjected to impacts of 35 to 420 kilobars amplitude and approximately 1 ms pulse width to investigate the timing spread of four pins and the voltage output profile of the individual pins. Sets of pins were also aged at 45{degree}, 60{degree} and 80{degree}C for approximately nine weeks before shock testing at 315 kilobars impact stress. Four sets of pins were heated to 50.2{degree}C (125{degree}F) for approximately two hours and then impactedmore » at either 50 or 315 kilobars. Also, four sets of pins were aged at 60{degree}C for nine weeks and then heated to 50.2{degree}C before shock testing at 50 and 315 kilobars impact stress, respectively. Particle velocity measurements at the contact point between the stainless steel targets and TOAD pins were made using a Velocity Interferometer System for Any Reflector (VISAR) to monitor both the amplitude and profile of the shock waves. {copyright} {ital 1996 American Institute of Physics.}« less

Shock characterization of TOAD pins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weirick, L.J.; Navarro, N.J.

1995-08-01

The purpose of this program was to characterize Time Of Arrival Detectors (TOAD) pins response to shock loading with respect to risetime, amplitude, repeatability and consistency. TOAD pins were subjected to impacts of 35 to 420 kilobars amplitude and approximately 1 ms pulse width to investigate the timing spread of four pins and the voltage output profile of the individual pins. Sets of pins were also aged at 45{degrees}, 60{degrees}, and 80{degrees}C for approximately nine weeks before shock testing at 315 kilobars impact stress. Four sets of pins were heated to 50.2{degrees}C (125{degrees}F) for approximately two hours and then impactedmore » at either 50 or 315 kilobars. Also, four sets of pins were aged at 60{degrees}C for nine weeks and then heated to 50.2{degrees}C before shock testing at 50 and 315 kilobars impact stress, respectively. Particle velocity measurements at the contact point between the stainless steel targets and TOAD pins were made using a Velocity Interferometer System for Any Reflector (VISAR) to monitor both the amplitude and profile of the shock waves.« less

A novel fast optical switch based on two cascaded Terahertz Optical Asymmetric Demultiplexers (TOAD).

PubMed

Wang, Bing; Baby, Varghese; Tong, Wilson; Xu, Lei; Friedman, Michelle; Runser, Robert; Glesk, Ivan; Prucnal, Paul

2002-01-14

A novel optical switch based on cascading two terahertz optical asymmetric demultiplexers (TOAD) is presented. By utilizing the sharp edge of the asymmetric TOAD switching window profile, two TOAD switching windows are overlapped to produce a narrower aggregate switching window, not limited by the pulse propagation time in the SOA of the TOAD. Simulations of the cascaded TOAD switching window show relatively constant window amplitude for different window sizes. Experimental results on cascading two TOADs, each with a switching window of 8ps, but with the SOA on opposite sides of the fiber loop, show a minimum switching window of 2.7ps.

Exploiting intraspecific competitive mechanisms to control invasive cane toads (Rhinella marina)

PubMed Central

Crossland, Michael R.; Haramura, Takashi; Salim, Angela A.; Capon, Robert J.; Shine, Richard

2012-01-01

If invasive species use chemical weapons to suppress the viability of conspecifics, we may be able to exploit those species-specific chemical cues for selective control of the invader. Cane toads (Rhinella marina) are spreading through tropical Australia, with negative effects on native species. The tadpoles of cane toads eliminate intraspecific competitors by locating and consuming newly laid eggs. Our laboratory trials show that tadpoles find those eggs by searching for the powerful bufadienolide toxins (especially, bufogenins) that toads use to deter predators. Using those toxins as bait, funnel-traps placed in natural waterbodies achieved near-complete eradication of cane toad tadpoles with minimal collateral damage (because most native (non-target) species are repelled by the toads' toxins). More generally, communication systems that have evolved for intraspecific conflict provide novel opportunities for invasive-species control. PMID:22696528

The role of calcium in the nuclear maturation of Bufo arenarum oocytes.

PubMed

Zelarayán, Liliana I; Toranzo, Graciela Sánchez; Oterino, Julia M; Bühler, Marta I

2004-02-01

In Bufo arenarum, progesterone is the physiological maturation inducer. However, in this species, oocytes reinitiate meiosis with no need of an exogenous hormonal stimulus when deprived of their enveloping cell, a phenomenon called spontaneous maturation. We demonstrated that in Bufo arenarum spontaneous maturation occurs only in oocytes obtained during the reproductive period, which can be considered competent to mature spontaneously, in contrast to those in the non-reproductive period, which are incompetent. Interestingly, full-grown Bufo arenarum oocytes always respond to progesterone regardless of the season in which they are obtained. There is a general consensus that both a transient increase in intracellular calcium and a decrease in cAMP-dependent protein kinase activity are the first steps in the mechanisms by which progesterone induces maturation in amphibians. In the present work we analysed the role of calcium in the spontaneous and progesterone-induced maturation of Bufo arenarum oocytes. Results demonstrated that the absence of calcium in the incubation medium or the prevention of Ca(2+) influx by channel blockers such as CdCl2 or NiCl2 did not prevent meiosis reinitiation in either type of maturation. The inhibition of the Ca(2+)-calmodulin complex in no case affected the maturation of the treated oocytes. However, when the oocytes were deprived of calcium by incubation in Ca(2+)-free AR + A23187, meiosis resumption was inhibited. In brief, we demonstrated that in Bufo arenarum the reinitiation of meiosis is a process independent of extracellular calcium at any period of the year and that oocytes require adequate levels of intracellular calcium for germinal vesicle breakdown to occur.

Lack of significant changes in the herpetofauna of Theodore Roosevelt National Park, North Dakota, since the 1920s

USGS Publications Warehouse

Hossack, B.R.; Corn, P.S.; Pilliod, D.S.

2005-01-01

We surveyed 88 upland wetlands and 12 1-km river sections for amphibians in Theodore Roosevelt National Park, North Dakota, during 2001–2002 to gather baseline data for future monitoring efforts and to evaluate changes in the distribution of species. We compared our results to collections of herpetofauna made during 1920–1922, 1954 and 1978–1979. The boreal chorus frog (Pseudacris maculata) was the most common amphibian in upland wetlands, followed by the tiger salamander (Ambystoma tigrinum), Woodhouse's toad (Bufo woodhousii), northern leopard frog (Rana pipiens), plains spadefoot (Spea bombifrons) and the Great Plains toad (B. cognatus). Bufo woodhousii was the only species that bred in the river. Our records for reptiles are less complete than for amphibians but no losses from the community are evident. The herpetofauna in Theodore Roosevelt National Park seems unchanged during at least the last half-century and likely since 1920–1922.

Transferable Output ASCII Data (TOAD) editor version 1.0 user's guide

NASA Technical Reports Server (NTRS)

Bingel, Bradford D.; Shea, Anne L.; Hofler, Alicia S.

1991-01-01

The Transferable Output ASCII Data (TOAD) editor is an interactive software tool for manipulating the contents of TOAD files. The TOAD editor is specifically designed to work with tabular data. Selected subsets of data may be displayed to the user's screen, sorted, exchanged, duplicated, removed, replaced, inserted, or transferred to and from external files. It also offers a number of useful features including on-line help, macros, a command history, an 'undo' option, variables, and a full compliment of mathematical functions and conversion factors. Written in ANSI FORTRAN 77 and completely self-contained, the TOAD editor is very portable and has already been installed on SUN, SGI/IRIS, and CONVEX hosts.

Locomotor performance of cane toads differs between native-range and invasive populations.

PubMed

Kosmala, Georgia; Christian, Keith; Brown, Gregory; Shine, Richard

2017-07-01

Invasive species provide a robust opportunity to evaluate how animals deal with novel environmental challenges. Shifts in locomotor performance-and thus the ability to disperse-(and especially, the degree to which it is constrained by thermal and hydric extremes) are of special importance, because they might affect the rate that an invader can spread. We studied cane toads ( Rhinella marina ) across a broad geographical range: two populations within the species' native range in Brazil, two invasive populations on the island of Hawai'i and eight invasive populations encompassing the eastern, western and southern limits of the toad invasion in Australia. A toad's locomotor performance on a circular raceway was strongly affected by both its temperature and its hydration state, but the nature and magnitude of those constraints differed across populations. In their native range, cane toads exhibited relatively low performance (even under optimal test conditions) and a rapid decrease in performance at lower temperatures and hydration levels. At the other extreme, performance was high in toads from southern Australia, and virtually unaffected by desiccation. Hawai'ian toads broadly resembled their Brazilian conspecifics, plausibly reflecting similar climatic conditions. The invasion of Australia has been accompanied by a dramatic enhancement in the toads' locomotor abilities, and (in some populations) by an ability to maintain locomotor performance even when the animal is cold and/or dehydrated. The geographical divergences in performance among cane toad populations graphically attest to the adaptability of invasive species in the face of novel abiotic challenges.

Different susceptibility of two aquatic vertebrates (Oncorhynchus mykiss and Bufo arenarum) to azinphos methyl and carbaryl.

PubMed

Ferrari, Ana; Anguiano, Olga L; Soleño, Jimena; Venturino, Andrés; Pechen de D'Angelo, Ana M

2004-12-01

We studied the effect of two insecticides azinphos methyl and carbaryl on two resident aquatic species (Oncorhynchus mykiss and Bufo arenarum). Juvenile trout and larval stages of toad were used for exposure and recovery assays. O. mykiss was more sensitive to azinphos methyl exposure than B. arenarum larvae, with a mean 96-h LC50 of 0.007 mg/l. Carbaryl is markedly less toxic than the organophosphate and the differences in potency, expressed as LC50, for both species varies only by five-fold. The relationship between cholinesterase (ChE) inhibition and lethality is not straightforward: O. mykiss survives with an almost complete inhibition of the brain enzyme when exposed to azinphos methyl and carbaryl. Their IC50 values are one or two orders of magnitude lower than the corresponding 96-h LC50 value. In B. arenarum larvae, the IC50 values for azinphos methyl and carbaryl are one half and one third of their 96-h LC50s, respectively. The time courses of enzyme inhibition and recovery also points out differences between both types of pesticides and species. Identifying the key features conferring species selectivity can be exploited to minimize the incidence and severity of intoxication of non-target organism. The data presented here highlight the necessity of including several species and endpoint analyses in the pesticide risk evaluations of aquatic ecosystems.

Host-pathogen metapopulation dynamics suggest high elevation refugia for boreal toads

USGS Publications Warehouse

Mosher, Brittany A.; Bailey, Larissa L.; Muths, Erin L.; Huyvaert, Kathryn P

2018-01-01

Emerging infectious diseases are an increasingly common threat to wildlife. Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is an emerging infectious disease that has been linked to amphibian declines around the world. Few studies exist that explore amphibian-Bd dynamics at the landscape scale, limiting our ability to identify which factors are associated with variation in population susceptibility and to develop effective in situdisease management. Declines of boreal toads (Anaxyrus boreas boreas) in the Southern Rocky Mountains are largely attributed to chytridiomycosis but variation exists in local extinction of boreal toads across this metapopulation. Using a large-scale historic dataset, we explored several potential factors influencing disease dynamics in the boreal toad-Bd system: geographic isolation of populations, amphibian community richness, elevational differences, and habitat permanence. We found evidence that boreal toad extinction risk was lowest at high elevations where temperatures may be sub-optimal for Bd growth and where small boreal toad populations may be below the threshold needed for efficient pathogen transmission. In addition, boreal toads were more likely to recolonize high elevation sites after local extinction, again suggesting that high elevations may provide refuge from disease for boreal toads. We illustrate a modeling framework that will be useful to natural resource managers striving to make decisions in amphibian-Bdsystems. Our data suggest that in the southern Rocky Mountains high elevation sites should be prioritized for conservation initiatives like reintroductions.

Stress hormone is implicated in satellite-caller associations and sexual selection in the Great Plains toad.

PubMed

Leary, Christopher J; Garcia, Apryl M; Knapp, Rosemary

2006-10-01

The effects of androgens on male-typical traits suggest that variation among males in circulating levels can play a major role in sexual selection. We examined whether variation in vocal attractiveness is attributable to differences in androgen levels among Great Plains toads (Bufo cognatus). We found that noncalling "satellite" males practicing an alternative mating tactic were more likely to associate with males producing long calls. However, callers with satellites did not have higher androgen levels than callers without satellites. Rather, callers with satellites had significantly lower corticosterone (CORT) levels than callers without satellites. A CORT manipulation experiment suggested that differences in calls for males with and without satellites were related to differences in CORT levels. Furthermore, there was a negative correlation between CORT level and call duration within most nights of chorus activity. However, the correlation was weak for the pooled data (across all nights), suggesting that local environmental and/or social factors also affect call duration. Last, we show that females preferred broadcast calls of longer duration, characteristic of males with satellites and low CORT. These results imply that satellites optimize their reproductive success by associating with males producing long calls. However, this association should negatively affect the fitness of attractive callers.

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

USGS Publications Warehouse

Mitrovich, M.J.; Gallegos, E.A.; Lyren, L.M.; Lovich, R.E.; Fisher, R.N.

2011-01-01

Information on the habitat use and movement patterns of Arroyo Toads (Anaxyrus californicus) is limited. The temporal and spatial characteristics of terrestrial habitat use, especially as it relates to upland use in coastal areas of the species' range, are poorly understood. We present analyses of radiotelemetry data from 40 individual adult toads tracked at a single site in coastal southern California from March through November of 2004. We quantify adult Arroyo Toad habitat use and movements and interpret results in the context of their life history. We show concentrated activity by both male and female toads along stream terraces during and after breeding, and, although our fall sample size is low, the continued presence of adult toads in the floodplain through the late fall. Adult toads used open sandy flats with sparse vegetation. Home-range size and movement frequency varied as a function of body mass. Observed spatial patterns of movement and habitat use both during and outside of the breeding period as well as available climatological data suggest that overwintering of toads in floodplain habitats of near-coastal areas of southern California may be more common than previously considered. If adult toads are not migrating out of the floodplain at the close of the breeding season but instead overwinter on stream terraces in near-coastal areas, then current management practices that assume toad absence from floodplain habitats may be leaving adult toads over-wintering on stream terraces vulnerable to human disturbance during a time of year when Arroyo Toad mortality is potentially highest. ?? 2011 Society for the Study of Amphibians and Reptiles.

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

USGS Publications Warehouse

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

2011-01-01

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

Transferable Output ASCII Data (TOAD) gateway: Version 1.0 user's guide

NASA Technical Reports Server (NTRS)

Bingel, Bradford D.

1991-01-01

The Transferable Output ASCII Data (TOAD) Gateway, release 1.0 is described. This is a software tool for converting tabular data from one format into another via the TOAD format. This initial release of the Gateway allows free data interchange among the following file formats: TOAD; Standard Interface File (SIF); Program to Optimize Simulated Trajectories (POST) input; Comma Separated Value (TSV); and a general free-form file format. As required, additional formats can be accommodated quickly and easily.

[Content of indole alkaloids and bufadienolides contained in toad medicines].

PubMed

Qu, Ting; Gao, Hui-Min; Chen, Liang-Mian; Wang, Zhi-Min; Zhang, Qi-Wei; Cheng, Yi-Yu

2012-10-01

To kinds of establish a HPLC method for determining contents of indole alkaloids and bufadienolides contained in toad medicines, and analyze two kinds of components contained in toad venom, toad skin and toad periostracum. As for alkaloids, Nucleosil C18 column was adopted with acetonitrile and water containing 0.5% potassium dihydrogen phosphate (6: 94, adjust pH to 3.2 with phosphate acid) as the mobile phase. The flow rate was 0.8 mL x min(-1), the detection wavelength was 275 nm, and the column temperature was 30 degrees C. As for bufadienolides, Alltima C18 column was adopted with acetonitrile and water containing 0.3% acetic acid (B) as the mobile phase. The gradient process was as follows: a linear gradient from 28% to 54% acetonitrile in the first 15 min, then kept at 54% for additional 20 min. The flow rate was 0.6 mL x min(-1), the detection wavelength was 296 nm, and the column temperature was 30 degrees C. The linear ranges were 0.079 6-0.796 microg for serotonin, 0.097 2-1.945 microg for N-methylserotonin, 0.074 4-0.744 microg for N,N-dimethylserotonin, 0.103-2.05 microg for N,N,N-trimethylserotonin, and 0.067 2-0.672 microg for bufothionine, respectively. The average recoveries of serotonin and N-methylserotonin were 98.6% and 91.3%, respectively. The linear ranges of gamabufotalin, bufotalin, bufalin, cinobufagin and resibufogenin were 0.004 83-0.614, 0.007 9-1.006, 0.007 95-1.016, 0.009 7-1.24 and 0.009 6-1.22 microg, respectively, and their average recoveries were 101.6%, 102.5%, 101.0%, 99.1% and 98.9%, respectively. Toad venom has the highest contents of indole alkaloids and bufadienolides, followed by toad skin, and toad periostracum showed the lowest contents and even no detection result.

Involvement of purines and phosphoinositides in spontaneous and progesterone-induced nuclear maturation of Bufo arenarum oocytes.

PubMed

Zelarayán, L; Oterino, J; Sánchez Toranzo, G; Bühler, M I

2000-07-01

Although progesterone is the established maturation inducer in amphibia, it has been demonstrated that Bufo arenarum oocytes resume meiosis with no need of an exogenous hormonal stimulus if deprived of their enveloping follicle cells, a phenomenon called "spontaneous maturation." The present studies were designed to evaluate the participation of purines and phosphoinositides in the spontaneous and progesterone-induced maturation in Bufo arenarum full-grown oocytes. The presented data demonstrate that high intracellular levels of purines such as cAMP or guanosine can inhibit both spontaneous and progesterone-induced maturation in full-grown denuded Bufo arenarum oocytes. Moreover, the fact that the mycophenolic acid was able to induce maturation in denuded oocytes obtained during the nonreproductive period in a manner similar to that of the progesterone and also to increase the percentages of spontaneous maturation suggests that in Bufo arenarum, inosine monophosphate dehydrogenase inhibition is an important step in the resumption of meiosis. Inhibition of the phosphatidylinositol 4,5 bisphosphate hydrolysis by treatment of denuded oocytes with neomycin totally blocks spontaneous and progesterone-induced maturation, suggesting that the products of this hydrolysis (1,2 diacylglycerol and inositol 1,4,5 trisphosphate) may be involved in the maturation process of Bufo. In addition, our results indicate that the activation of protein kinase C is also involved in both types of maturation.

Viral discovery in the invasive Australian cane toad (Rhinella marina) using metatranscriptomic and genomic approaches.

PubMed

Russo, Alice G; Eden, John-Sebastian; Enosi Tuipulotu, Daniel; Shi, Mang; Selechnik, Daniel; Shine, Richard; Rollins, Lee Ann; Holmes, Edward C; White, Peter A

2018-06-13

Cane toads are a notorious invasive species, inhabiting over 1.2 million km 2 of Australia and threatening native biodiversity. Release of pathogenic cane toad viruses is one possible biocontrol strategy yet is currently hindered by the poorly-described cane toad virome. Metatranscriptomic analysis of 16 cane toad livers revealed the presence of a novel and full-length picornavirus, Rhimavirus A (RhiV-A), a member of a reptile and amphibian specific-cluster of the Picornaviridae basal to the Kobuvirus -like group. In the combined liver transcriptome, we also identified a complete genome sequence of a distinct epsilonretrovirus, R. marina endogenous retrovirus (RMERV). The recently sequenced cane toad genome contains eight complete RMERV proviruses, as well as 21 additional truncated insertions. The oldest full length RMERV provirus was estimated to have inserted 1.9 MYA. To screen for these viral sequences in additional toads, we analysed publicly available transcriptomes from six diverse Australian locations. RhiV-A transcripts were identified in toads sampled from three locations across 1,000 km of Australia, stretching to the current Western Australia (WA) invasion front, whilst RMERV transcripts were observed at all six sites. Lastly, we scanned the cane toad genome for non-retroviral endogenous viral elements, finding three sequences related to small DNA viruses in the family Circoviridae This shows ancestral circoviral infection with subsequent genomic integration. The identification of these current and past viral infections enriches our knowledge of the cane toad virome, an understanding of which will facilitate future work on infection and disease in this important invasive species. Importance Cane toads are poisonous amphibians which were introduced to Australia in 1935 for insect control. Since then, their population has increased dramatically, and they now threat many native Australian species. One potential method to control the population is to

Effects of nitrate on metamorphosis, thyroid and iodothyronine deiodinases expression in Bufo gargarizans larvae.

PubMed

Wang, Ming; Chai, Lihong; Zhao, Hongfeng; Wu, Minyao; Wang, Hongyuan

2015-11-01

Chinese toad (Bufo gargarizans) tadpoles were exposed to nitrate (10, 50 and 100mg/L NO3-N) from the beginning of the larval period through metamorphic climax. We examined the effects of chronic nitrate exposure on metamorphosis, mortality, body size and thyroid gland. In addition, thyroid hormone (TH) levels, type II iodothyronine deiodinase (Dio2) and type III iodothyronine deiodinase (Dio3) mRNA levels were also measured to assess disruption of TH synthesis. Results showed that significant metamorphic delay and mortality increased were caused in larvae exposed to 100mg/L NO3-N. The larvae exposed to 100mg/L NO3-N clearly exhibited a greater reduction in thyroxine (T4) and 3,5,3'-triiodothyronine (T3) levels. Moreover, treatment with NO3-N induced down-regulation of Dio2 mRNA levels and up-regulation of Dio3 mRNA levels, reflecting the disruption of thyroid endocrine. It seems that increased mass and body size may be correlated with prolonged metamorphosis. Interestingly, we observed an exception that exposure to 100mg/L NO3-N did not exhibit remarkable alterations of thyroid gland size. Compared with control groups, 100mg/L NO3-N caused partial colloid depletion in the thyroid gland follicles. These results suggest that nitrate can act as a chemical stressor inducing retardation in development and metamorphosis. Therefore, we concluded that the presence of high concentrations nitrate can influence the growth, decline the survival, impair TH synthesis and induce metamorphosis retardation of B. gargarizans larvae. Copyright © 2015 Elsevier Ltd. All rights reserved.

Diseases of frogs and toads

USGS Publications Warehouse

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

2005-01-01

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

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

PubMed

Santana, A S; Juncá, F A

2007-02-01

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

Cortical granule exocytosis in Bufo arenarum oocytes matured in vitro.

PubMed

Oterino, J; Sanchez Toranzo, G; Zelarayán, L; Valz-Gianinet, J N; Bühler, M I

2001-08-01

Denuded Bufo arenarum oocytes matured in vitro by progesterone treatment exhibited abnormal segmentation due to the penetration of more than one sperm. These oocytes were able to respond to activation stimuli and exhibited the external signs characteristic of activation. However, the prevention of polyspermy was not effective in these oocytes, which exhibited numerous sperm in their cytoplasm. The aim of this work was to analyse the cortical reaction in polyspermic Bufo arenarum oocytes matured in vitro. The result indicate that the cortical reaction of these oocytes seems to occur with a chronological sequence similar to that described for ovoposited oocytes of this species. In addition, when, 1 min after pricking, cortical granule exocytosis occurred, the oocytes became refractory to sperm entry, suggesting that they are able to establish a slow block to polyspermy.

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

PubMed

Purwaningsih, Endang; Dewi, Kartika; Hasegawa, Hideo

2015-06-24

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

New Weapons in the Toad Toolkit: A Review of Methods to Control and Mitigate the Biodiversity Impacts of Invasive Cane Toads (Rhinella Marina).

PubMed

Tingley, Reid; Ward-Fear, Georgia; Schwarzkopf, Lin; Greenlees, Matthew J; Phillips, Benjamin L; Brown, Gregory; Clulow, Simon; Webb, Jonathan; Capon, Robert; Sheppard, Andy; Strive, Tanja; Tizard, Mark; Shine, Richard

2017-06-01

Our best hope of developing innovative methods to combat invasive species is likely to come from the study of high-profile invaders that have attracted intensive research not only into control, but also basic biology. Here we illustrate that point by reviewing current thinking about novel ways to control one of the world’s most well-studied invasions: that of the cane toad in Australia. Recently developed methods for population suppression include more effective traps based on the toad’s acoustic and pheromonal biology. New tools for containing spread include surveillance technologies (e.g., eDNA sampling and automated call detectors), as well as landscape-level barriers that exploit the toad’s vulnerability to desiccation—a strategy that could be significantly enhanced through the introduction of sedentary, range-core genotypes ahead of the invasion front. New methods to reduce the ecological impacts of toads include conditioned taste aversion in free-ranging predators, gene banking, and targeted gene flow. Lastly, recent advances in gene editing and gene drive technology hold the promise of modifying toad phenotypes in ways that may facilitate control or buffer impact. Synergies between these approaches hold great promise for novel and more effective means to combat the toad invasion and its consequent impacts on biodiversity.

11beta-hydroxysteroid dehydrogenase in the testis of Bufo arenarum: changes in its seasonal activity.

PubMed

Denari, Daniela; Ceballos, Nora R

2005-09-01

In rat Leydig cells, glucocorticoids (GC) inhibit testosterone (T) synthesis via glucocorticoid receptor (GR). However, GC access to GR is regulated by the local expression of 11beta-hydroxysteroid dehydrogenase (11beta-HSD). Two isoforms were identified in mammals: type 1, a NADP+-preferring enzyme with K(m) in the muM range for GC and type 2, NAD+-dependent, with K(m) in the nM range for GC. In amphibians, a seasonal rhythm in baseline GC levels was described. However, a shift in the amount of deactivating 11beta-HSD activity could alter GC effects. The purpose of this work is to describe seasonal changes in testicular activity of 11beta-HSD in Bufo arenarum as well as the annual and seasonal patterns of plasma corticosterone (B) and T. The activity of 11beta-HSD was assayed in homogenate and subcellular fractions in pre-reproductive (Pre-R), reproductive (R) and post-reproductive (Post-R) periods, using [3H]B. Plasma B and T were determined by RIA. Testicular 11beta-HSD is a microsomal NAD+-dependent enzyme with a K(m) in the nM order, its activity being strongly reduced by glycyrrhetinic acid. These results indicate that toad testes express an 11beta-HSD similar to mammalian type 2. Although 11beta-HSD activity is higher in the Post-R than in the R and Pre-R seasons (V(max): Pre-R: 0.26+/-0.10, R: 0.14+/-0.01, Post-R: 1.37+/-0.45, pmol/minmg protein), K(m) value remains constant throughout the year. A seasonal rhythm in baseline GC concentrations inversely correlated with plasma T was also described. T concentration is lower in the R season than in the other periods (Pre-R: 90+/-6; R: 12+/-1; Post-R: 56+/-3, nM) while total B concentration is higher in the breeding than in the other seasons (Pre-R: 62+/-10; R: 145+/-18; Post-R: 96+/-10, nM). Furthermore, free B (Pre-R: 51+/-8; R: 94+/-12; Post-R: 70+/-7, nM) was always below K(m) values. In conclusion, this work shows that the activity of 11beta-HSD in toad testes could modulate GC action by transforming active

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

USGS Publications Warehouse

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

2004-01-01

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

COMPARATIVE DIABETOGENIC ACTION OF THE HYPOPHYSIS FROM VARIOUS ANIMALS

PubMed Central

Houssay, B. A.; Smyth, F. S.; Foglia, V. G.; Houssay, A. B.

1942-01-01

Of all the anterior hypophyses tested, those of the human produced the most marked diabetogenic action in the dog with its pancreatic tissue reduced to 4 gm., and in the hypophysectomized and pancreatectomized toad. The human hypophysis also produced diabetogenic action in the normal dog on daily doses of 1.26 mg. per kilo per day for 2 days. The hypophysectomized dog with its pancreas reduced to 4 gm. is very sensitive to the anterior hypophyseal diabetogenic action and is the best test animal for demonstrating such action in mammals. The anterior hypophysis of man, toad, rat, and chicken produces in such animals a diabetogenic action with doses of from 10 to 15 mg. per kilo per day. The bovine anterior hypophysis has identical action in 20 mg. doses. That of canine origin was much less active in a few though inconclusive experiments. It was impossible to demonstrate a diabetogenic action with either guinea pig hypophysis or with that of fish probably because insufficient doses were injected. The diabetogenic action was not obtained by the injection of other organ extracts of toads, dogs and oxen, of corticosterone (30, 40, and 60 mg. in 4 days) or of desoxycorticosterone (80 mg. and 200 mg. in 4 days). The toad (Bufo arenarum Hensel), deprived of its hypophysis and pancreas is the most sensitive biological reactor for testing the diabetogenic action. In this animal the diabetogenic action of anterior hypophyses from varied sources decreased in the following order: man, dog, toad (Bufo arenarum Hensel), white rat, guinea pig, chicken (whole hypophysis), ox, serpent (Constrictor constrictor (L.)), the fish "corvina" Micropogon opercularis (Quoy and Gaimard, 1824), and "merluza" Merlucius hubbsi (Marini, 1933). PMID:19871171

Antibacterial activity of lactose-binding lectins from Bufo arenarum skin.

PubMed

Sánchez Riera, Alicia; Daud, Adriana; Gallo, Adriana; Genta, Susana; Aybar, Manuel; Sánchez, Sara

2003-04-01

Amphibians respond to microbial infection through cellular and humoral defense mechanisms such as antimicrobial protein secretion. Most humoral defense proteins are synthetized in the skin. In this study we isolated two beta-galactoside-binding lectins with molecular weights of 50 and 56 KDa from the skin of Bufo arenarum. These lectins have significant hemagglutination activity against trypsinized rabbit erythrocytes, which was inhibited by galactose-containing saccharides. They are water-soluble and independent of the presence of calcium. The antimicrobial analysis for each lectin was performed. At mumolar concentration lectins show strong bacteriostatic activity against Gram negative bacteria (Escherichia coli K12 4100 and wild strains of Escherichia coli and Proteus morganii) and Gram positive bacteria (Enterococcus faecalis). The antibacterial activity of these lectins may provide an effective defense against invading microbes in the amphibian Bufo arenarum.

Alfaxalone versus alfaxalone-dexmedetomidine anaesthesia by immersion in oriental fire-bellied toads (Bombina orientalis).

PubMed

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

2016-05-01

To determine a dexmedetomidine concentration, to be added to an alfaxalone-based bath solution, that will enhance the anaesthetic and analgesic effects of alfaxalone; and to compare the quality of anaesthesia and analgesia provided by immersion with either alfaxalone alone or alfaxalone with dexmedetomidine in oriental fire-bellied toads (Bombina orientalis). Pilot study followed by a prospective, randomized, experimental trial. Fourteen oriental fire-bellied toads. The pilot study aimed to identify a useful dexmedetomidine concentration to be added to an anaesthetic bath containing 20 mg 100 mL(-1) alfaxalone. Thereafter, the toads were assigned to one of two groups, each comprising eight animals, to be administered either alfaxalone (group A) or alfaxalone-dexmedetomidine (group AD). After immersion for 20 minutes, the toads were removed from the anaesthetic bath and the righting, myotactic and nociceptive reflexes, cardiopulmonary variables and von Frey filaments threshold were measured at 5 minute intervals and compared statistically between groups. Side effects and complications were noted and recorded. In the pilot study, a dexmedetomidine concentration of 0.3 mg 100 mL(-1) added to the alfaxalone-based solution resulted in surgical anaesthesia. The toads in group AD showed higher von Frey thresholds and lower nociceptive withdrawal reflex scores than those in group A. However, in group AD, surgical anaesthesia was observed in two out of eight toads only, and induction of anaesthesia was achieved in only 50% of the animals, as compared with 100% of the toads in group A. The addition of dexmedetomidine to an alfaxalone-based solution for immersion anaesthesia provided some analgesia in oriental fire-bellied toads, but failed to potentiate the level of unconsciousness and appeared to lighten the depth of anaesthesia. This limitation renders the combination unsuitable for anaesthetizing oriental fire-bellied toads for invasive procedures. © 2015

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

PubMed

Vincent, Kim; Davidson, Carlos

2015-12-01

Pesticide choice based on toxicity to nontarget wildlife is reliant on available toxicity data. Despite a number of recent studies examining the effects of glyphosate on amphibians, very few have aimed to understand the toxicological effects of glyphosate in combination with surfactants as it is commonly applied in the field. Land managers interested in making pesticide choices based on minimizing impacts to nontarget wildlife are hindered by a lack of published toxicity data. Short-term acute toxicity trials were conducted for glyphosate in the form of isopropylamine salt (IPA) alone and mixed with 2 surfactants: Agri-dex and Competitor with western toad (Anaxyrus [Bufo] boreas) tadpoles. Glyphosate IPA mixed with Competitor was 6 times more toxic than glyphosate IPA mixed with Agri-dex, and both mixtures were more toxic than glyphosate IPA alone. The median lethal concentrations reported for 24-h and 48-h exposures were 8279 mg/L (24 h) and 6392 mg/L (48 h) for glyphosate IPA alone; 5092 mg/L (24 h) and 4254 mg/L (48 h) for glyphosate IPA mixed with Agri-dex; and 853 mg/L (24 h) and 711 mg/L (48 h) for glyphosate IPA mixed with Competitor. The present study indicates that the toxicity of a tank mix may be greatly increased by the addition of surfactants and may vary widely depending on the specific surfactant. © 2015 SETAC.

Trypanosome transmitted by Phlebotomus: first report from the Americas.

PubMed

Anderson, J R; Ayala, S C

1968-09-06

Transmission studies carried out in the laboratory incriminated Phlebotomus vexator occidentis as a vector of a species of trypanosome that infects Bufo boreas halophilus. Toads free of parasites contracted the trypanosome after eating infected flies and after intraperitoneal inoculation of flagellates cultured from the hindgut of flies that had fed on infected toads. Discovery of this vectorhost-parasite system in the Americas, and the localization of promastigote flagellates (leptomonads) in the hindgut of the vector, should assist in clarifying interpretative problems associated with infection of wild-caught flies in studies on leishmaniasis in the Americas and elsewhere.

Success of capture of toads improved by manipulating acoustic characteristics of lures.

PubMed

Muller, Benjamin J; Schwarzkopf, Lin

2017-11-01

Management of invasive vertebrates is a crucial component of conservation. Trapping reproductive adults is often effective for control, and modification of traps may greatly increase their attractiveness to such individuals. Cane toads (Rhinella marina) are invasive, and males use advertisement vocalisations to attract reproductive females. In amphibians, including toads, specific structural parameters of calls (e.g. dominant frequency and pulse rate) may be attractive to females. Some cane toad traps use an artificial advertisement vocalisation to attract toads. We determined whether variation of the call's parameters (volume, dominant frequency and pulse rate) could increase the capture rate of gravid females. Overall, traps equipped with loud calls (80 dB at 1 m) caught significantly more toads, and proportionally more gravid females, than traps with quiet calls (60 dB at 1 m), and traps with low dominant frequency calls caught more gravid females than traps with median frequency calls. Traps with high pulse rate calls attracted more females than traps with low pulse rate calls. Approximately 91% of the females trapped using a low frequency and high pulse rate combination call were gravid, whereas in traps using a call with population median parameters only approximately 75% of captured females were gravid. Calls that indicated large-bodied males (low frequency) with high energy reserves (high pulse rate) are often attractive to female anurans and were effective lures for female toads in our study. The design of future trapping regimes should account for behavioural preferences of the target sex. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Urinary corticosterone metabolite responses to capture and captivity in the cane toad (Rhinella marina).

PubMed

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

2011-09-01

Urinary corticosterone metabolite responses to capture have recently been shown for the first time in amphibians, and in the present study urinary corticosterone metabolite responses to capture and to confinement in captivity were measured in adult cane toads (Rhinella marina) in Queensland, Australia. An adrenocorticotropic hormone (ACTH) challenge was used to provide a biological validation for urinary corticosterone metabolite concentrations measured by radioimmunoassay (RIA). Urinary corticosterone metabolite increased 1-2 days after ACTH but not saline injection and then returned to initial values, indicating that the RIA could detect changes in corticosterone secretion in toads. Urinary corticosterone metabolite responses to short-term capture and restraint in plastic bags were first apparent 2h after capture of wild toads. Toads held communally in captivity for 5 days had elevated urinary corticosterone metabolite concentrations. Mean corticosterone concentrations declined significantly after a further 7 days in individual housing chambers. There was no sex difference in urinary corticosterone metabolite responses of toads to ACTH challenge, short-term capture or captivity. The relative amount of variation in the mean corticosterone responses was quantified by calculating coefficients of variation (CV) for each mean corticosterone response. Mean corticosterone at 0 min was more variable for captive toads than wild toads. Furthermore, initial corticosterone concentrations (0 min) were more variable than concentrations during the ACTH challenge, short-term capture and captivity. There was little change in the amount of variation of mean corticosterone levels between male and female toads with increasing time in captivity (12-29 days). This study has shown individual corticosterone responses of amphibians for the first-time, and has provided a novel method for quantifying the relative amount of variation in amphibian corticosterone responses. Copyright © 2011

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

PubMed

Hartel, Tibor; von Wehrden, Henrik

2013-01-01

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

Lueheia inscripta (Westrumb, 1821) (Acanthocephala: Plagiorhynchidae) in anurans (Leptodactylidae: Bufonidae) from Mexico.

PubMed

Salgado-Maldonado, G; Caspeta-Mandujano, J M

2010-06-01

Juveniles of Lueheia inscripta (Westrumb, 1821 Travassos, 1919 (Acanthocephala: Plagiorhynchidae), an acanthocephalan with six lemnisci, are reported and described from mesenteries of frogs Leptodactylus fragilis Brochi, 1877 and a toad Bufo marinus (Linnaeus, 1758) from Morelos state, Mexico. These are new host records extending the known geographical distribution of this species from Brazil and Puerto Rico to Mexico.

Slope-based and geometric encoding of a goal location by the terrestrial toad (Rhinella arenarum).

PubMed

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

2017-11-01

The current study was designed to test for the ability of terrestrial toads, Rhinella arenarum , to use slope as source of spatial information to locate a goal, and investigate the relative importance of slope and geometric information for goal localization. Toads were trained to locate a single, water-reward goal location in a corner of a rectangular arena placed on an incline. Once the toads learned the task, 3 types of probe trials were carried out to determine the relative use of slope and geometric information for goal localization. The probe trials revealed that the toads were able to independently use slope, and as previously reported, geometry to locate the goal. However, the boundary geometry of the experimental arena was found to be preferentially used by the toads when geometric and slope information were set in conflict. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

The archipelago of Fernando de Noronha: an intriguing malformed toad hotspot in South America.

PubMed

Toledo, Luís Felipe; Ribeiro, Ricardo S

2009-09-01

Malformed anurans raise concern among scientists, because deformities may relate to the recent global crisis among amphibian populations, although declining populations also may be associated with other causes (e.g., diseases, over-exploitation, and land use/land cover change). We examined a sample of toads (Rhinella jimi, Bufonidae) from an introduced population in the Archipelago of Fernando de Noronha, Brazil where malformations of anurans were thought to be high. Our sample of 159 specimens from the site revealed that 44.6% of all specimens had one or more malformations. Incidence of malformed toads on the mainland sites was substantially lower: 10.5% at Itamaracá, and 3.7% at Propriá. We describe the malformations observed, including six undescribed types of malformation of anurans, and we pose possible hypotheses to explain this high incidence of malformed toads. In addition to existing hypotheses, we suggest for the first time the hypothesis that lack of predation pressures contributes to numbers of malformed toads. We indicate the need of specific studies to understand the causes of malformations in the R. jimi population of Fernando de Noronha, which is thought to be extreme foci of malformed amphibians in the world. Our results may improve local conservation action plans as this is an alien population that may be affecting endemic fauna, and may affect populations in other parts of the world, because toad species of the genus Rhinella are recognized as exceptional colonizers. More importantly, unknown variables in these toads' environment are evidently affecting toads during development, which should be a concern for all species that inhabit the area, perhaps even humans.

In vivo and in vitro heterogeneity of segment length changes in the semimembranosus muscle of the toad

PubMed Central

Ahn, A N; Monti, R J; Biewener, A A

2003-01-01

Many studies examine sarcomere dynamics in single fibres or length–tension dynamics in whole muscles in vivo or in vitro, but few studies link the various levels of organisation. To relate data addressing in vitro muscle segment behaviour with in vivo whole muscle behaviour during locomotion, we measured in vivo strain patterns of muscle segments using three sonomicrometry crystals implanted along a fascicle of the semimembranosus muscle in the American toad (Bufo americanus; n = 6) during hopping. The centre crystal emitted an ultrasonic signal, while the outer crystals received the signal allowing the instantaneous measurement of lengths from two adjacent muscle segments. On the first day, we recorded from the central and distal segments. On the second day of recordings, the most distal crystal was moved to a proximal position to record from a proximal segment and the same central segment. When the toads hopped a distance of two body lengths, the proximal and central segments strained −15.1 ± 6.1 and −14.0 ± 4.9 % (i.e. shortening), respectively. Strain of the distal segment, however, was significantly lower and more variable in pattern, often lengthening before shortening during a hop. From rest length, the distal segment initially lengthened by 2.6 ± 2.0 % before shortening by 6.5 ± 3.2 % at the same hop distance. Under in vitro conditions, the central segment always shortened more than the distal segment, except when passively cycled, during which the segments strained similarly. When the whole muscle was cycled sinusoidally and stimulated phasically in vitro, the two adjacent segments strained in opposite directions over much (up to 34 %) of the cycle. These differences in strain amplitude and direction imply that two adjacent segments can not only produce and/or absorb varying amounts of mechanical energy, but can also operate on different regions of their force–length and force–velocity relationships when activated by the same neural signal

[Comparison of chemical composition between fresh and processed Bufonis Venenum by UPLC-TQ-MS].

PubMed

Wang, Zi-yue; Wang, Hong-lan; Zhou, Jing; Ma, Hong-yue; Gong, Yan; Yan, Wen-li; Qian, Da-wei

2015-10-01

Toad venom is the Bufo bufo gargarizans or B. melanostictus after the ears of the gland secretion, used in the treatment of various cancers in recent years. Research shows that the main anti-tumor components in bufadienolide. Bufadienolide have free type structure and conjunct type structure. To identify and clarify the difference between bufogenin and bufotoxin contained in Bufonis Venenum, which was from B. bufo gargarizans, an UPLC-TQ-MS method has been established. UPLC-TQ-MS method was used to identify and quantify the major bufadienolides in Bufonis Venenum. UPLC-TQ-MS assay with positive ion mode was performed on a Waters ACQUITY UPLC BEH C, (2.1 mm x 100 mm, 1.7 µm) with the mobile phase consisting of 0. 1% aqueous formic and acidacetonitrile in gradient elution at a flow rate of 0.4 mL · min⁻¹ and the column temperature was set at 35 °C. By comparing their retention time and high resolution mass data of Bufonis Venenum extracts, 37 effective components were primarily identified by MS/MS analysis in positive ion mode. Twenty-six of them were free-type bufadienolides (bufogenin), 11 of them were conjugated bufadienolides. There were significant differences in the main composition between fresh and processed Bufonis Venenum. The study found that the chemical composition of toad venom through great changes after processing, conjunct type content is much less, free type content as well change.

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

PubMed

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

2015-10-01

The objective of the present study was to evaluate the efficacy and the safety of etomidate anaesthesia by immersion technique in Bombina orientalis. The study comprised two phases. The first phase was carried out to identify the etomidate concentration capable of producing anaesthetic induction, as well as surgical anaesthesia, in the toads. The second phase was aimed at testing that concentration in eight additional animals. Etomidate administered via immersion at a concentration of 37.5 mg/L produced effective anaesthesia in oriental fire-bellied toads. The average duration of surgical anaesthesia was 20 min. All the toads enrolled in the study survived the anaesthesia and long-term complications did not occur. However, undesired side-effects, namely itching, myoclonus and prolonged recovery, were noticed during the perianaesthetic period. The authors concluded that etomidate anaesthesia by immersion, at a concentration of 37.5 mg/L, is suitable in oriental fire-bellied toads and produces anaesthesia of a depth and duration that is sufficient to allow the completion of various experimental procedures, without resulting in lethal complications. However, the occurrence of undesired side-effects opens a debate on the safety of this anaesthetic technique, and imposes the need for further investigation prior to proposing the latter for routine laboratory practice. © The Author(s) 2015.

A Deduction of the Golden Spiral Equation via Powers of the Golden Ratio ?

ERIC Educational Resources Information Center

Zahn, Maurício

2017-01-01

This paper presents an interesting deduction of the Golden Spiral equation in a suitable polar coordinate system. For this purpose, the concepts of Golden Ratio and Golden Rectangle, and a significant result for the calculation of powers of the Golden Ratio ? using terms of the Fibonacci sequence are mentioned. Finally, various geometrical…

Farmed Areas Predict the Distribution of Amphibian Ponds in a Traditional Rural Landscape

PubMed Central

Hartel, Tibor; von Wehrden, Henrik

2013-01-01

Background Traditional rural landscapes of Eastern Europe are undergoing major changes due to agricultural intensification, land abandonment, change in agricultural practices and infrastructural development. Small man-made ponds are important yet vulnerable components of rural landscapes. Despite their important role for biodiversity, these ponds tend to be excluded from conservation strategies. Methodology/Findings Our study was conducted in a traditional rural landscape in Eastern Europe. The aim of this study is twofold: (i) to model the distribution of four major man-made pond types and (ii) to present the importance of man-made ponds for the endangered Yellow Bellied Toad (Bombina variegata) and the Common Toad (Bufo bufo). Six environmental variables were used to model pond distribution: Corine landcover, the heterogeneity of the landcover, slope, road distance, distance to closest village and the human population density. Land cover heterogeneity was the most important driver for the distribution of fishponds. Areas used for agriculture with significant areas of natural vegetation were the most important predictors for the distribution of temporary ponds. In addition, areas covered by transitional woodland and scrub were important for the open cattle ponds. Bombina variegata was found predominantly in the temporary ponds (e.g. ponds created by cattle and buffalo, dirt road ponds and concrete ponds created for livestock drinking) and Bufo bufo in fishponds. Conclusions/Significance Our Maxent models revealed that the highest probability of occurrence for amphibian ponds was in areas used as farmland. The traditional farming practices combined with a low level of infrastructure development produces a large number of amphibian ponds. The challenge is to harmonize economic development and the maintenance of high densities of ponds in these traditional rural landscapes. PMID:23704928

The Golden Ratio

ERIC Educational Resources Information Center

Hyde, Hartley

2004-01-01

The Golden Ratio is sometimes called the "Golden Section" or the "Divine Proportion", in which three points: A, B, and C, divide a line in this proportion if AC/AB = AB/BC. "Donald in Mathmagicland" includes a section about the Golden Ratio and the ratios within a five-pointed star or pentagram. This article presents two computing exercises that…

Sudden death associated with intravenous injection of toad extract.

PubMed

Kostakis, Chris; Byard, Roger W

2009-07-01

A 24-year-old male died suddenly following the intravenous injection of what was believed to be the ring-derivate amphetamine 'ecstasy' (MDMA). Toxicological analyses of the victim's blood and the injected material, however, failed to reveal MDMA, but showed instead low levels of bufotenine, a tryptamine derivative alkaloid found in the secretions of various toads. In addition, resibufogenin, cinobufagin and bufalin, bufadienolides that are also found in toad venom, were identified in the injected material. While these substances also occur in certain South American plants, the finding of paracetamol, promethazine and diclofenac would be in keeping with ingredients found in the traditional Chinese herbal product Chan Su that derives from the skin glands and secretions of toads and that is often adulterated with standard pharmaceutical drugs. This case demonstrates the problems that users and sellers may encounter from the unknown composition of street drugs and herbal medicines, and the danger that may be incurred from the injection of such materials. It also shows the difficulties that may be associated with attempting to identify low levels of organic toxins in postmortem specimens necessitating a targeted screening approach guided by information obtained at the death scene.

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

PubMed

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

2016-05-27

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

Effect of salt acclimation on digitalis-like compounds in the toad.

PubMed

Lichtstein, D; Gati, I; Babila, T; Haver, E; Katz, U

1991-01-23

Digitalis-like compounds (DLC) were shown to be a normal constituent of the skin and plasma of toads. In order to assess the possible physiological role of these compounds in the toad, their levels were determined in the brain, plasma and skin following acclimation in different NaCl solutions. We demonstrate that an increase in salt concentrations in the animal medium from 0 to 1.2% decreased the levels of DLC in the brain by 50% without altering significantly its levels in the plasma and skin. An increase in medium salt concentration to 1.5% resulted in a 50% increase of DLC levels in the skin without changing its levels in the plasma or brain. These results suggest that skin and brain DLC may participate in the long-term salt and water homeostasis in the toad, while the plasma compound either participates in the short-term regulations of salt and water homeostasis or have some other, unknown, function.

Relocation of the 146th Tactical Airlift Wing of the California Air National Guard. Volume 2. Appendices

DTIC Science & Technology

1985-08-01

Status *Non-native species Y A L D GNETAE Ephedraceae - Joint Fir Family Ephedra nevadensis C 0 A Nevada Morman Tea DICOTYLEDONES 3 Asteraceae...tortoise Crotalus viridis Western rattlesnake Crotalus cerastes Sidewinder Tantilla planiceps Black-headed snake Bufo boreas Common toad Xantusia viiilis...plant community is Joshua Tree Woodland with Mormon STea ( Ephedra sp.?), Cholla (Opuntia sp.?), Creosote-bush (Larrea Divaricata), Red Brome (Bromus

Phlebotomus Sandflies of the Paloich Area in the Sudan (Diptera, Psychodidae)

DTIC Science & Technology

1964-10-01

Hamster, Cricetus auratus Toad, Bufo regularis (?) Gecko, H. turicus Skink, M. striata Puff adder Snake, CMNH HH-9111’ Snake, CMNH HH-9112’ Hedgehog ...Pharynx unarmed distally or only with few, smail spines ; pigment patch not dark enough to obscure teeth .................. 8 Pharynx heavily...armed distally with numerous, dark spines ; pigment patch very dark, 1964 Quate: Sudanese sandflies 237 often obscuring teeth unless specimen well

Factors Affecting Students' Attitudes toward Toads

ERIC Educational Resources Information Center

Tomažic, Iztok; Šorgo, Andrej

2017-01-01

Amphibians are one of the most threatened animal groups; however, attitudes and emotions toward them are mostly negative. One of the efforts, as a part of the cognitive dimension of nature protection, should be in the shifting of negative attitudes toward amphibians to positive ones. The purpose of this study was reevaluation of the Toad Attitude…

Behavioural divergence during biological invasions: a study of cane toads (Rhinella marina) from contrasting environments in Hawai'i.

PubMed

Gruber, Jodie; Brown, Gregory; Whiting, Martin J; Shine, Richard

2018-04-01

Invasive species must deal with novel challenges, both from the alien environment and from pressures arising from range expansion per se (e.g. spatial sorting). Those conditions can create geographical variation in behaviour across the invaded range, as has been documented across regions of Australia invaded by cane toads; range-edge toads are more exploratory and willing to take risks than are conspecifics from the range-core. That behavioural divergence might be a response to range expansion and invasion per se , or to the different environments encountered. Climate differs across the cane toads' invasion range from the wet tropics of Queensland to the seasonally dry climates of northwestern Western Australia. The different thermal and hydric regimes may affect behavioural traits via phenotypic plasticity or through natural selection. We cannot tease apart the effects of range expansion versus climate in an expanding population but can do so in a site where the colonizing species was simultaneously released in all suitable areas, thus removing any subsequent phase of range expansion. Cane toads were introduced to Hawai'i in 1932; and thence to Australia in 1935. Toads were released in all major sugarcane-growing areas in Hawai'i within a 12-month period. Hence, Hawai'ian cane toads provide an opportunity to examine geographical divergence in behavioural traits in a climatically diverse region (each island has both wet and dry sides) in the absence of range expansion subsequent to release. We conducted laboratory-based behavioural trials testing exploration, risk-taking and response to novelty using field-caught toads from the wet and dry sides of two Hawai'ian islands (Oahu and Hawai'i). Toads from the dry side of Oahu had a higher propensity to take risks than did toads from the dry side of Hawai'i. Toads from Oahu were also more exploratory than were conspecifics from the island of Hawai'i. However, toads from wet versus dry climates were similar in all

Behavioural divergence during biological invasions: a study of cane toads (Rhinella marina) from contrasting environments in Hawai'i

PubMed Central

2018-01-01

Invasive species must deal with novel challenges, both from the alien environment and from pressures arising from range expansion per se (e.g. spatial sorting). Those conditions can create geographical variation in behaviour across the invaded range, as has been documented across regions of Australia invaded by cane toads; range-edge toads are more exploratory and willing to take risks than are conspecifics from the range-core. That behavioural divergence might be a response to range expansion and invasion per se, or to the different environments encountered. Climate differs across the cane toads' invasion range from the wet tropics of Queensland to the seasonally dry climates of northwestern Western Australia. The different thermal and hydric regimes may affect behavioural traits via phenotypic plasticity or through natural selection. We cannot tease apart the effects of range expansion versus climate in an expanding population but can do so in a site where the colonizing species was simultaneously released in all suitable areas, thus removing any subsequent phase of range expansion. Cane toads were introduced to Hawai'i in 1932; and thence to Australia in 1935. Toads were released in all major sugarcane-growing areas in Hawai'i within a 12-month period. Hence, Hawai'ian cane toads provide an opportunity to examine geographical divergence in behavioural traits in a climatically diverse region (each island has both wet and dry sides) in the absence of range expansion subsequent to release. We conducted laboratory-based behavioural trials testing exploration, risk-taking and response to novelty using field-caught toads from the wet and dry sides of two Hawai'ian islands (Oahu and Hawai'i). Toads from the dry side of Oahu had a higher propensity to take risks than did toads from the dry side of Hawai'i. Toads from Oahu were also more exploratory than were conspecifics from the island of Hawai'i. However, toads from wet versus dry climates were similar in all

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mezhzherin, S.V.; Pisanets, E.M.

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

Effect of parathyroid hormone on transport by toad and turtle bladder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabatini, S.; Kurtzman, N.A.

1987-01-01

The authors recently demonstrated that parathyroid hormone (PTH) inhibited both vasopressin- and cyclic AMP-stimulated water transport in the toad bladder. This was associated with an increase in calcium uptake by isolated epithelial cells. They postulated that PTH exerts its action on H/sub 2/O transport by directly stimulating calcium uptake. The current study was designed to compare the effects of PTH and the calcium ionophore, A23187, on H/sub 2/O and Na transport and H..mu.. secretion in toad and turtle bladders. In toad bladder, PTH and A23187 decreased arginine vasopressin (AVP)-stimulated H/sub 2/O flow and short-circuit current (SCC) after 60 min serosalmore » incubation. In turtle bladder A23187 decreased SCC to 79.3 +/- 3.6% of base line (P < 0.05), and significantly decreased RSCC as well. PTH had no effect on SCC or H/sup +/ secretion in turtle bladders. Both PTH and A23187 increased /sup 45/Ca uptake in toad bladder epithelial cells; only A23187 increased /sup 45/Ca uptake in the turtle bladder. The different action of PTH in these two membranes, compared with that of the calcium ionophore, illustrates the selectivity of PTH on membrane transport. PTH increases calcium uptake and decreases transport only in a hormone-sensitive epithelium, whereas the ionophore works in virtually all living membranes. The mode of action of these two agents to increase calcium uptake is, therefore likely different.« less

The Acid Test: pH Tolerance of the Eggs and Larvae of the Invasive Cane Toad (Rhinella marina) in Southeastern Australia.

PubMed

Wijethunga, Uditha; Greenlees, Matthew; Shine, Richard

2015-01-01

Invasive cane toads are colonizing southeastern Australia via a narrow coastal strip sandwiched between unsuitable areas (Pacific Ocean to the east, mountains to the west). Many of the available spawning sites exhibit abiotic conditions (e.g., temperature, salinity, and pH) more extreme than those encountered elsewhere in the toad's native or already invaded range. Will that challenge impede toad expansion? To answer that question, we measured pH in 35 ponds in northeastern New South Wales and 8 ponds in the Sydney region, in both areas where toads occur (and breed) and adjacent areas where toads are likely to invade, and conducted laboratory experiments to quantify effects of pH on the survival and development of toad eggs and larvae. Our field surveys revealed wide variation in pH (3.9-9.8) among natural water bodies. In the laboratory, the hatching success of eggs was increased at low pH (down to pH 4), whereas the survival, growth, and developmental rates of tadpoles were enhanced by higher pH levels. We found that pH influenced metamorph size and shape (relative head width, relative leg length) but not locomotor performance. The broad tolerance range of these early life-history stages suggests that pH conditions in ponds will not significantly slow the toad's expansion southward. Indeed, toads may benefit from transiently low pH conditions, and habitat where pH in wetlands is consistently low (such as coastal heath) may enhance rather than reduce toad reproductive success. A broad physiological tolerance during embryonic and larval life has contributed significantly to the cane toad's success as a widespread colonizer.

Reported Experiences Enhance Favourable Attitudes toward Toads

ERIC Educational Resources Information Center

Tomazic, Iztok

2011-01-01

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

Identification of Bufadienolides from the Boreal Toad, Anaxyrus boreas, Active Against a Fungal Pathogen.

PubMed

Barnhart, Kelly; Forman, Megan E; Umile, Thomas P; Kueneman, Jordan; McKenzie, Valerie; Salinas, Irene; Minbiole, Kevin P C; Woodhams, Douglas C

2017-11-01

Amphibian granular glands provide a wide range of compounds on the skin that defend against pathogens and predators. We identified three bufadienolides-the steroid-like compounds arenobufagin, gamabufotalin, and telocinobufagin-from the boreal toad, Anaxyrus boreas, through liquid chromatography mass spectrometry (LC/MS). Compounds were detected both after inducing skin gland secretions and in constitutive mucosal rinses from toads. We described the antimicrobial properties of each bufadienolide against Batrachochytrium dendrobatidis (Bd), an amphibian fungal pathogen linked with boreal toad population declines. All three bufadienolides were found to inhibit Bd growth at similar levels. The maximum Bd inhibition produced by arenobufagin, gamabufotalin, and telocinobufagin were approximately 50%, in contrast to the complete Bd inhibition shown by antimicrobial skin peptides produced by some amphibian species. In addition, skin mucus samples significantly reduced Bd viability, and bufadienolides were detected in 15 of 62 samples. Bufadienolides also appeared to enhance growth of the anti-Bd bacterium Janthinobacterium lividum, and thus may be involved in regulation of the skin microbiome. Here, we localized skin bacteria within the mucus layer and granular glands of toads with fluorescent in situ hybridization. Overall, our results suggest that bufadienolides can function in antifungal defense on amphibian skin and their production is a potentially convergent trait similar to antimicrobial peptide defenses found on the skin of other species. Further studies investigating bufadienolide expression across toad populations, their regulation, and interactions with other components of the skin mucosome will contribute to understanding the complexities of amphibian immune defense.

First report of exotic ticks (Amblyomma rotundatum) parasitizing invasive cane toads (Rhinella marina) on the Island of Hawai'i.

PubMed

Kelehear, Crystal; Hudson, Cameron M; Mertins, James W; Shine, Richard

2017-02-01

Our surveys of 1401 invasive cane toads (Rhinella marina) from the Hawaiian islands of Hawai'i, O'ahu, and Maui revealed the presence of an exotic tick, Amblyomma rotundatum. Immature and adult female ticks infested three wild adult toads at a single site in the vicinity of a zoo south of Hilo, Island of Hawai'i, Hawai'i, USA. We found no tick-infested toads on O'ahu or Maui. This tick infests cane toads in their native Neotropical range, but it was excluded from Hawai'i when the original founder toads were introduced over 80 years ago. The circumstances of our discovery suggest that A. rotundatum was independently and belatedly introduced to Hawai'i with imported zoo animals, and Hawai'i now joins Florida as the second U.S. state where this tick is established. Published by Elsevier GmbH.

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

PubMed

Brown, Gregory P; Shine, Richard

2014-01-01

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

Constructing an Invasion Machine: The Rapid Evolution of a Dispersal-Enhancing Phenotype During the Cane Toad Invasion of Australia.

PubMed

Hudson, C M; McCurry, M R; Lundgren, P; McHenry, C R; Shine, R

Biological invasions can induce rapid evolutionary change. As cane toads (Rhinella marina) have spread across tropical Australia over an 80-year period, their rate of invasion has increased from around 15 to 60 km per annum. Toads at the invasion front disperse much faster and further than conspecifics from range-core areas, and their offspring inherit that rapid dispersal rate. We investigated morphological changes that have accompanied this dramatic acceleration, by conducting three-dimensional morphometric analyses of toads from both range-core and invasion-front populations. Morphology of heads, limbs, pectoral girdles and pelvic girdles differed significantly between toads from the two areas, ranging from 0.5% to 16.5% difference in mean bone dimensions between populations, with invasion-front toads exhibiting wider forelimbs, narrower hindlimbs and more compact skulls. Those changes plausibly reflect an increased reliance on bounding (multiple short hops in quick succession) rather than separate large leaps. Within an 80-year period, invasive cane toads have converted the basic anuran body plan - which evolved for occasional large leaps to evade predators - into a morphotype better-suited to sustained long-distance travel.

Aspects of the reproductive ecology and behavior of the tepui toads, genus Oreophrynella (Anura: Bufonidae)

USGS Publications Warehouse

McDiarmid, R.W.; Gorzula, S.

1989-01-01

We report direct development for toads of the bufonid genus Oreophrynella, endemic to the tepuis of the Guayanan Highlands. Tepui toads place few (9-13), large (-3 mm diameter) eggs in a single or communal terrestrial nest. One communal nest found on Kukenan-tepui contained 102 toads (70 males, 30 females, 2 hatchlings) and 321 eggs in clumps of 8-35. All viable clutches from Kukenan were attended by an adult. One clutch of 13 eggs from Ilu-tepui was without an attendant adult. Calls of Kukenan males consist of 9-16 partially pulsed notes given at a rate of 5-7 notes per second. Calls and notes were modulated and increased or decreased in frequency; dominant frequencies of the calls ranged between 2650-3650 Hz. Tepui toads are diurnal, rock dwellers with a slow, deliberate walking gait. An unusual balling and tumbling behavior and bright colored venter may be associated with predator avoidance in some populations. Remarkable parallels in reproductive ecology and behavior between Oreophynella and montane populations of the African bufonid Nectophrynoides are noted.

The Interacting Effects of Ungulate Hoofprints and Predatory Native Ants on Metamorph Cane Toads in Tropical Australia

PubMed Central

Cabrera-Guzmán, Elisa; Crossland, Michael R.; González-Bernal, Edna; Shine, Richard

2013-01-01

Many invasive species exploit the disturbed habitats created by human activities. Understanding the effects of habitat disturbance on invasion success, and how disturbance interacts with other factors (such as biotic resistance to the invaders from the native fauna) may suggest new ways to reduce invader viability. In tropical Australia, commercial livestock production can facilitate invasion by the cane toad (Rhinella marina), because hoofprints left by cattle and horses around waterbody margins provide distinctive (cool, moist) microhabitats; nevertheless the same microhabitat can inhibit the success of cane toads by increasing the risks of predation or drowning. Metamorph cane toads actively select hoofprints as retreat-sites to escape dangerous thermal and hydric conditions in the surrounding landscape. However, hoofprint geometry is important: in hoofprints with steep sides the young toads are more likely to be attacked by predatory ants (Iridomyrmex reburrus) and are more likely to drown following heavy rain. Thus, anthropogenic changes to the landscape interact with predation by native taxa to affect the ability of cane toads in this vulnerable life-history stage to thrive in the harsh abiotic conditions of tropical Australia. PMID:24255703

Effects of dieldrin treatment on physiological and biochemical aspects of the toad embryonic development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gauna, L.; Caballero de Castro, A.; Chifflet de Llamas, M.

1991-04-01

Dieldrin is a cylclodiene insecticide highly persistent in nature due to its chemical stability. The exposure of toad embryos to Dieldrin induces hyperactivity in the swimming larvae and inhibition of cholinesterases. However, the inhibition of these enzymes during early development is not life threatening. The present report provides a physiological and biochemical study of the noxious effect of Dieldrin on the toad embryonic development.

Low doses of urethane effectively inhibit spinal seizures evoked by sudden cooling of toad isolated spinal cord

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pina-crespo, J.C.; Dalo, N.L.

1992-01-01

The effect of low doses of urethane on three phases of spinal seizures evoked by sudden cooling (SSSC) of toad isolated spinal cord was studied. In control toads, SSSC began with a latency of 91[plus minus]3 sec exhibiting brief tremors, followed by clonic muscle contractions and finally reaching a tonic contraction. The latency of onset of seizures was significantly enhanced. The tonic phase was markedly abolished in toads pretreated intralymphaticaly with 0.15 g/kg of urethane. Tremors were the only phase observed in 55% of toads that received doses of 0.2 g/kg, and a total blockage of seizures was seen aftermore » doses of 0.25 g/kg of urethane in 50% of the preparations. A possible depressant effect of urethane on transmission mediated by excitatory amino acids is suggested.« less

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

PubMed

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

2009-01-15

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

Seasonal variation in the thermal biology of a terrestrial toad, Rhinella icterica (Bufonidae), from the Brazilian Atlantic Forest.

PubMed

Anderson, Rodolfo César de Oliveira; Bovo, Rafael Parelli; Andrade, Denis Vieira

2018-05-01

As ectotherms, amphibians may exhibit changes in their thermal biology associated with spatial and temporal environmental contingencies. However, our knowledge on how amphibian´s thermal biology responds to seasonal changes in the environment is restricted to a few species, mostly from temperate regions, in a marked contrast with the high species diversity found in the Neotropics. We investigated whether or not the seasonal variation in climatic parameters from a high-montane ombrophilous forest in the Brazilian Atlantic Forest could lead to concurrent adjustments in the thermal biology of the terrestrial toad Rhinella icterica. We measured active body temperature (T b ) in the field, and preferred body temperature (T pref ) and thermal tolerance (critical thermal minimum, CT min , and maximum, CT max ) in the laboratory, for toads collected at two distinct seasons: warm/wet and cold/dry. We also measured operative environmental temperatures (T e ) using agar toad models coupled with dataloggers distributed in different microhabitats in the field to estimate accuracy (d b ) and effectiveness (E) of thermoregulation of the toads for both seasons. Toads had higher T pref in the warm/wet season compared to the cold/dry season, even though no seasonal change occurred in field T b 's. In the warm/wet season, toads decreased the accuracy of thermoregulation and avoided thermally favorable microhabitats, while in the cold/dry season they increased the accuracy of thermoregulation and exhibited high degree of thermoconformity. This result may encompass thermoregulatory adjustments to seasonal changes in T e 's, but may also reflect seasonal differences in compromises between T b regulation and other ecologically relevant activities (reproduction, foraging). Toads did not exhibit changes in CT min or CT max , which indicates a low risk of exposure to extreme temperatures in this particular habitat, at both seasons, possibly combined with a low flexibility of this trait

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keller, D.C.; Nelson, E.I.; Mullen, M.A.

1998-07-01

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

Spontaneous and LH-induced maturation in Bufo arenarum oocytes: importance of gap junctions.

PubMed

Toranzo, G Sánchez; Oterino, J; Zelarayán, L; Bonilla, F; Bühler, M I

2007-02-01

It has been demonstrated in Bufo arenarum that fully grown oocytes are capable of meiotic resumption in the absence of a hormonal stimulus if they are deprived of their follicular envelopes. This event, called spontaneous maturation, only takes place in oocytes collected during the reproductive period, which have a metabolically mature cytoplasm. In Bufo arenarum, progesterone acts on the oocyte surface and causes modifications in the activities of important enzymes, such as a decrease in the activity of adenylate cyclase (AC) and the activation of phospholipase C (PLC). PLC activation leads to the formation of diacylglycerol (DAG) and inositol triphosphate (IP(3)), second messengers that activate protein kinase C (PKC) and cause an increase in intracellular Ca(2+). Recent data obtained from Bufo arenarum show that progesterone-induced maturation causes significant modifications in the level and composition of neutral lipids and phospholipids of whole fully grown ovarian oocytes and of enriched fractions in the plasma membrane. In amphibians, the luteinizing hormone (LH) is responsible for meiosis resumption through the induction of progesterone production by follicular cells. The aim of this work was to study the importance of gap junctions in the spontaneous and LH-induced maturation in Bufo arenarum oocytes. During the reproductive period, Bufo arenarum oocytes are capable of undergoing spontaneous maturation in a similar way to mammalian oocytes while, during the non-reproductive period, they exhibit the behaviour that is characteristic of amphibian oocytes, requiring progesterone stimulation for meiotic resumption (incapable oocytes). This different ability to mature spontaneously is coincident with differences in the amount and composition of the phospholipids in the oocyte membranes. Capable oocytes exhibit in their membranes higher quantities of phospholipids than incapable oocytes, especially of PC and PI, which are precursors of second messengers such as

The Golden Section.

ERIC Educational Resources Information Center

Runion, Garth E.

The Golden Section, also known as the "Golden Mean" and the "Divine Proportion," is a ratio found in art and nature that has mathematical properties. This book explores these geometric and algebraic properties in a variety of activities. Construction problems, designs using the pentagon and pentagram, and opportunities to work…

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

USGS Publications Warehouse

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

2013-01-01

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

Effect of insulin on spontaneous and progesterone-induced GVBD on Bufo arenarum denuded oocytes.

PubMed

Sánchez Toranzo, G; Bonilla, F; Zelarayán, L; Oterino, J; Bühler, M I

2004-08-01

Progesterone is considered as the physiological steroid hormone that triggers meiosis reinitiation in amphibian oocytes. Nevertheless, isolated oocytes can be induced to undergo germinal vesicle breakdown (GVBD) in a saline medium by means of treatment with various hormones or inducing agents such as other steroid hormones, insulin or an insulin-like growth factor. It has been demonstrated that Bufo arenarum oocytes obtained during the reproductive period (spring-summer) resume meiosis with no need of an exogenous hormonal stimulus if deprived of their enveloping follicle cells, a phenomenon called spontaneous maturation. This study was undertaken to evaluate the participation of the purine and phosphoinositide pathway in the insulin-induced maturation of oocytes competent and incompetent to mature spontaneously, as well as to determine whether the activation of the maturation promoting factor (MPF) involved the activation of cdc25 phosphatase in Bufo arenarum denuded oocytes. Our results indicate that insulin was able to induce GBVD in oocytes incompetent to mature spontaneously and to enhance spontaneous and progesterone-induced maturation. In addition, high intracellular levels of purines such as cAMP or guanosine can reversibly inhibit the progesterone and insulin-induced maturation process in Bufo arenarum as well as spontaneous maturation. Assays of the inhibition of phosphatidylinositol-4,5-bisphosphate (PIP2) hydrolysis and its turnover by neomycin and lithium chloride respectively exhibited a different response in insulin- or progesterone-treated oocytes, suggesting that phosphoinositide turnover or hydrolysis of PIP2 is involved in progesterone- but not in insulin-induced maturation. In addition, the inhibitory effect of vanadate suggests that an inactive pre-maturation promoting factor (pre-MPF), activated by dephosphorylation of Thr-14 and Tyr-15 on p34cdc2, is present in Bufo arenarum full-grown oocytes; this step would be common to both spontaneous

Effects of invasion history on physiological responses to immune system activation in invasive Australian cane toads

PubMed Central

West, Andrea J.; Brown, Gregory P.; Fanson, Kerry V.; Addison, BriAnne; Rollins, Lee A.; Shine, Richard

2017-01-01

The cane toad (Rhinella marina) has undergone rapid evolution during its invasion of tropical Australia. Toads from invasion front populations (in Western Australia) have been reported to exhibit a stronger baseline phagocytic immune response than do conspecifics from range core populations (in Queensland). To explore this difference, we injected wild-caught toads from both areas with the experimental antigen lipopolysaccharide (LPS, to mimic bacterial infection) and measured whole-blood phagocytosis. Because the hypothalamic-pituitary-adrenal axis is stimulated by infection (and may influence immune responses), we measured glucocorticoid response through urinary corticosterone levels. Relative to injection of a control (phosphate-buffered saline), LPS injection increased both phagocytosis and the proportion of neutrophils in the blood. However, responses were similar in toads from both populations. This null result may reflect the ubiquity of bacterial risks across the toad’s invaded range; utilization of this immune pathway may not have altered during the process of invasion. LPS injection also induced a reduction in urinary corticosterone levels, perhaps as a result of chronic stress. PMID:29018604

Why is golden rice golden (yellow) instead of red?

PubMed

Schaub, Patrick; Al-Babili, Salim; Drake, Rachel; Beyer, Peter

2005-05-01

The endosperm of Golden Rice (Oryza sativa) is yellow due to the accumulation of beta-carotene (provitamin A) and xanthophylls. The product of the two carotenoid biosynthesis transgenes used in Golden Rice, phytoene synthase (PSY) and the bacterial carotene desaturase (CRTI), is lycopene, which has a red color. The absence of lycopene in Golden Rice shows that the pathway proceeds beyond the transgenic end point and thus that the endogenous pathway must also be acting. By using TaqMan real-time PCR, we show in wild-type rice endosperm the mRNA expression of the relevant carotenoid biosynthetic enzymes encoding phytoene desaturase, zeta-carotene desaturase, carotene cis-trans-isomerase, beta-lycopene cyclase, and beta-carotene hydroxylase; only PSY mRNA was virtually absent. We show that the transgenic phenotype is not due to up-regulation of expression of the endogenous rice pathway in response to the transgenes, as was suggested to be the case in tomato (Lycopersicon esculentum) fruit, where CRTI expression resulted in a similar carotenoid phenomenon. This means that beta-carotene and xanthophyll formation in Golden Rice relies on the activity of constitutively expressed intrinsic rice genes (carotene cis-trans-isomerase, alpha/beta-lycopene cyclase, beta-carotene hydroxylase). PSY needs to be supplemented and the need for the CrtI transgene in Golden Rice is presumably due to insufficient activity of the phytoene desaturase and/or zeta-carotene desaturase enzyme in endosperm. The effect of CRTI expression was also investigated in leaves of transgenic rice and Arabidopsis (Arabidopsis thaliana). Here, again, the mRNA levels of intrinsic carotenogenic enzymes remained unaffected; nevertheless, the carotenoid pattern changed, showing a decrease in lutein, while the beta-carotene-derived xanthophylls increased. This shift correlated with CRTI-expression and is most likely governed at the enzyme level by lycopene-cis-trans-isomerism. Possible implications are

WEAKLY SYNCHRYRONIZED SUBPOPULATION DYNAMICS IN WISCONSIN FROGS AND TOADS

EPA Science Inventory

Spatial synchrony in population dynamics is a topic of increasing interest in basic and applied ecology. We used data from 18 years of frog and toad calling surveys conducted throughout Wisconsin to determine the level of intraspecific synchrony among survey sites, and the relat...

Effects of dehydration on plasma osmolality, thirst-related behavior, and plasma and brain angiotensin concentrations in Couch's spadefoot toad, Scaphiopus couchii.

PubMed

Johnson, W E; Propper, C R

2000-05-01

Under dehydrating conditions, many terrestrial vertebrates species exhibit increases in plasma osmolality and their drinking behavior. Under some circumstances, this behavioral change is accompanied by changes in plasma and central angiotensin concentrations, and it has been proposed that these changes in angiotensin levels induce the thirst-related behaviors. In response to dehydration, the spadefoot toad, Scaphiopus couchii, exhibits thirst-related behavior in the form of cutaneous drinking. This behavior has been termed water absorption response (WR) behavior. Spadefoot toads live in harsh desert environments and are subject annually to dehydrating conditions that may induce thirst-related behavior. We tested the hypothesis that an increase in WR behavior is associated with both an increase in plasma osmolality and an increase in plasma and brain angiotensin concentrations. First, we determined the degree of dehydration that was necessary to initiate WR behavior. Animals dehydrated to 85% of their standard bladder-empty weight via deprivation of water exhibited WR behavior more frequently than control toads left in home containers with water available. Next, using the same dehydration methods, we determined the plasma osmolality and sodium concentrations of dehydrated toads. Toads dehydrated to 85% standard weight also had a significant increase in plasma osmolality, but exhibited no overall change in plasma sodium concentrations, indicating that while an overall increase in plasma osmolality appears to be associated with WR behavior in S. couchii, changes in sodium concentrations alone are not sufficient to induce the behavior. Finally, plasma and brain angiotensin concentrations were measured in control toads and toads dehydrated to 85% standard weight. Plasma and brain angiotensin concentrations did not increase in dehydrated toads, indicating that dehydration-induced WR behavior that is associated with changes in plasma osmolality may not be induced by

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

USGS Publications Warehouse

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

2013-01-01

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

The Golden Section as Optical Limitation.

PubMed

Elliott, Mark A; Kelly, Joy; Friedel, Jonas; Brodsky, Jennifer; Mulcahy, Paul

2015-01-01

The golden section, ϕ = (1 + √5)/2 = 1.618... and its companion ϕ = 1/ϕ = ϕ -1 = 0.618..., are irrational numbers which for centuries were believed to confer aesthetic appeal. In line with the presence of golden sectioning in natural growth patterns, recent EEG recordings show an absence of coherence between brain frequencies related by the golden ratio, suggesting the potential relevance of the golden section to brain dynamics. Using Mondrian-type patterns comprising a number of paired sections in a range of five section-section areal ratios (including golden-sectioned pairs), participants were asked to indicate as rapidly and accurately as possible the polarity (light or dark) of the smallest section in the patterns. They were also asked to independently assess the aesthetic appeal of the patterns. No preference was found for golden-sectioned patterns, while reaction times (RTs) tended to decrease overall with increasing ratio independently of each pattern's fractal dimensionality. (Fractal dimensionality was unrelated to ratio and measured in terms of the Minkowski-Bouligand box-counting dimension). The ease of detecting the smallest section also decreased with increasing ratio, although RTs were found to be substantially slower for golden-sectioned patterns under 8-paired sectioned conditions. This was confirmed by a significant linear relationship between RT and ratio (p < .001) only when the golden-sectioned RTs were excluded [the relationship was non-significant for the full complement of ratios (p = .217)]. Image analysis revealed an absence of spatial frequencies between 4 and 8 cycles-per-degree that was exclusive to the 8-paired (golden)-sectioned patterns. The significance of this was demonstrated in a subsequent experiment by addition of uniformly distributed random noise to the patterns. This provided a uniform spatial-frequency profile for all patterns, which did not influence the decrease in RT with increasing ratio but abolished the elevated

Final Environmental Assessment for Installation Development at Little Rock Air Force Base Arkansas

DTIC Science & Technology

2006-10-18

southwest corners of the base. Long, narrow ridges, oriented from east to west, typify the region to the north of the base. The southernmost of these...grassy areas on base were limited to the three-toed box turtle (Terrapene carolina triunguis) and Fowler’s toad (Bufo woodhousei fowleri) (USAF 2002...known to other tribes as “Ugaxpa,” or “downstream people.” They settled four villages at the mouth of the Arkansas River where they remained until

Enviromental Assessment: Security Forces Regional Training Center at Little Rock Air Force Base Arkansas

DTIC Science & Technology

2004-07-14

stream valleys in the northwest and southwest corners of the base. Long, narrow ridges, oriented from east to west, typify the region to the north of...found in the grassy areas on base were limited to the three-toed box turtle (Terrapene carolina triunguis) and Fowler’s toad (Bufo woodhousei fowleri...other tribes as “Ugaxpa,” or “downstream people.” They settled four villages at the mouth of the Arkansas River where they remained until they were

Characterization of the Skin Microbiota of the Cane Toad Rhinella cf. marina in Puerto Rico and Costa Rica

PubMed Central

Abarca, Juan G.; Zuniga, Ibrahim; Ortiz-Morales, Gilmary; Lugo, Armando; Viquez-Cervilla, Mariel; Rodriguez-Hernandez, Natalia; Vázquez-Sánchez, Frances; Murillo-Cruz, Catalina; Torres-Rivera, Ernesto A.; Pinto-Tomás, Adrián A.; Godoy-Vitorino, Filipa

2018-01-01

Rhinella marina is a toad native to South America that has been introduced in the Antilles, likely carrying high loads of microorganisms, potentially impacting local community diversity. The amphibian skin is involved in pathogen defense and its microbiota has been relatively well studied, however, research focusing on the cane toad microbiota is lacking. We hypothesize that the skin microbial communities will differ between toads inhabiting different geographical regions in Central America and the Caribbean. To test our hypothesis, we compared the microbiota of three populations of R. cf. marina toads, two from Costa Rican (native) and one Puerto Rican (exotic) locations. In Costa Rica, we collected 11 toads, 7 in Sarapiquí and 4 from Turrialba while in Puerto Rico, 10 animals were collected in Santa Ana. Separate swab samples were collected from the dorsal and ventral sites resulting in 42 samples. We found significant differences in the structure of the microbial communities between Puerto Rico and Costa Rica. We detected as much as 35 different phyla; however, communities were dominated by Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. Alpha diversity and richness were significantly higher in toads from Puerto Rico and betadiversity revealed significant differences between the microbiota samples from the two countries. At the genus level, we found in Santa Ana, Puerto Rico, a high dominance of Kokuria, Niabella, and Rhodobacteraceae, while in Costa Rica we found Halomonas and Pseudomonas in Sarapiquí, and Acinetobacter and Citrobacter in Turrialba. This is the first report of Niabella associated with the amphibian skin. The core microbiome represented 128 Operational Taxonomic Units (OTUs) mainly from five genera shared among all samples, which may represent the symbiotic Rhinella’s skin. These results provide insights into the habitat-induced microbial changes facing this amphibian species. The differences in the microbial diversity in

Characterization of the Skin Microbiota of the Cane Toad Rhinella cf. marina in Puerto Rico and Costa Rica.

PubMed

Abarca, Juan G; Zuniga, Ibrahim; Ortiz-Morales, Gilmary; Lugo, Armando; Viquez-Cervilla, Mariel; Rodriguez-Hernandez, Natalia; Vázquez-Sánchez, Frances; Murillo-Cruz, Catalina; Torres-Rivera, Ernesto A; Pinto-Tomás, Adrián A; Godoy-Vitorino, Filipa

2017-01-01

Rhinella marina is a toad native to South America that has been introduced in the Antilles, likely carrying high loads of microorganisms, potentially impacting local community diversity. The amphibian skin is involved in pathogen defense and its microbiota has been relatively well studied, however, research focusing on the cane toad microbiota is lacking. We hypothesize that the skin microbial communities will differ between toads inhabiting different geographical regions in Central America and the Caribbean. To test our hypothesis, we compared the microbiota of three populations of R. cf. marina toads, two from Costa Rican (native) and one Puerto Rican (exotic) locations. In Costa Rica, we collected 11 toads, 7 in Sarapiquí and 4 from Turrialba while in Puerto Rico, 10 animals were collected in Santa Ana. Separate swab samples were collected from the dorsal and ventral sites resulting in 42 samples. We found significant differences in the structure of the microbial communities between Puerto Rico and Costa Rica. We detected as much as 35 different phyla; however, communities were dominated by Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. Alpha diversity and richness were significantly higher in toads from Puerto Rico and betadiversity revealed significant differences between the microbiota samples from the two countries. At the genus level, we found in Santa Ana, Puerto Rico, a high dominance of Kokuria , Niabella , and Rhodobacteraceae, while in Costa Rica we found Halomonas and Pseudomonas in Sarapiquí, and Acinetobacter and Citrobacter in Turrialba. This is the first report of Niabella associated with the amphibian skin. The core microbiome represented 128 Operational Taxonomic Units (OTUs) mainly from five genera shared among all samples, which may represent the symbiotic Rhinella 's skin. These results provide insights into the habitat-induced microbial changes facing this amphibian species. The differences in the microbial diversity in

Effects of long-term exposure to Cu2+ and Cd2+ on the pentose phosphate pathway dehydrogenase activities in the ovary of adult Bufo arenarum: possible role as biomarker for Cu2+ toxicity.

PubMed

Carattino, Marcelo D; Peralta, Susana; Pérez-Coll, Cristina; Naab, Fabián; Burlón, Alejandro; Kreiner, Andrés J; Preller, Ana F; de Schroeder, Teresa M Fonovich

2004-03-01

The effects of copper and cadmium on metabolism through the pentose phosphate pathway were evaluated in Bufo arenarum toad ovary. The effects of the two metals on dehydrogenases from this pathway were evaluated by three experiments: (1) in samples obtained from control females with addition of the metals to the reaction mixture (in vitro), (2) in samples obtained from control females and after long-term exposure of females to 4 and 100 microg/L of Cu or Cd in the incubation media (in vitro after exposure to the metals in vivo), and (3) 14CO2 production through the pentose phosphate pathway was evaluated after [U-14C]glucose microinjection on ovulated oocytes (in vivo after microinjection of the metals). Results from (1) evidenced inhibition of both enzyme activities but only above 1.5 mM Cu and Cd added to the reaction mixture. In (2) both glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities decreased in samples from the ovaries of females exposed in vivo to Cu, in a concentration-dependent manner (up to 90% in females exposed to 100 microg/L Cu: 2.12 +/- 1.57 NADPH micromol/min microg protein x 10(-5) vs 19.97 +/- 8.54 in control females). Cd treatment of the toads only rendered an inhibitory effect on 6-phosphogluconate dehydrogenase activity after exposure to 4 microg/L of the bivalent cation. (3) In vivo 14CO2 evolution significantly decreased in oocytes coinjected with 6.3 x 10(-3) mM Cu (calculated intracellular final concentration of the metal injected) and radioactive glucose. Cu and Cd concentration in samples from exposed females were always under detection limit by particle-induced X-ray emission. The results presented here are in agreement with a role for both glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities determination as biomarkers of effect and exposure for Cu but not for Cd toxicity.

Seasonal migrations, body temperature fluctuations, and infection dynamics in adult amphibians.

PubMed

Daversa, David R; Monsalve-Carcaño, Camino; Carrascal, Luis M; Bosch, Jaime

2018-01-01

Risks of parasitism vary over time, with infection prevalence often fluctuating with seasonal changes in the annual cycle. Identifying the biological mechanisms underlying seasonality in infection can enable better prediction and prevention of future infection peaks. Obtaining longitudinal data on individual infections and traits across seasons throughout the annual cycle is perhaps the most effective means of achieving this aim, yet few studies have obtained such information for wildlife. Here, we tracked spiny common toads ( Bufo spinosus ) within and across annual cycles to assess seasonal variation in movement, body temperatures and infection from the fungal parasite, Batrachochytrium dendrobatidis (Bd) . Across annual cycles, toads did not consistently sustain infections but instead gained and lost infections from year to year. Radio-tracking showed that infected toads lose infections during post-breeding migrations, and no toads contracted infection following migration, which may be one explanation for the inter-annual variability in Bd infections. We also found pronounced seasonal variation in toad body temperatures. Body temperatures approached 0 °C during winter hibernation but remained largely within the thermal tolerance range of Bd . These findings provide direct documentation of migratory recovery (i.e., loss of infection during migration) and escape in a wild population. The body temperature reductions that we observed during hibernation warrant further consideration into the role that this period plays in seasonal Bd dynamics.

Seasonal migrations, body temperature fluctuations, and infection dynamics in adult amphibians

PubMed Central

Daversa, David R.; Monsalve-Carcaño, Camino; Carrascal, Luis M.

2018-01-01

Risks of parasitism vary over time, with infection prevalence often fluctuating with seasonal changes in the annual cycle. Identifying the biological mechanisms underlying seasonality in infection can enable better prediction and prevention of future infection peaks. Obtaining longitudinal data on individual infections and traits across seasons throughout the annual cycle is perhaps the most effective means of achieving this aim, yet few studies have obtained such information for wildlife. Here, we tracked spiny common toads (Bufo spinosus) within and across annual cycles to assess seasonal variation in movement, body temperatures and infection from the fungal parasite, Batrachochytrium dendrobatidis (Bd). Across annual cycles, toads did not consistently sustain infections but instead gained and lost infections from year to year. Radio-tracking showed that infected toads lose infections during post-breeding migrations, and no toads contracted infection following migration, which may be one explanation for the inter-annual variability in Bd infections. We also found pronounced seasonal variation in toad body temperatures. Body temperatures approached 0 °C during winter hibernation but remained largely within the thermal tolerance range of Bd. These findings provide direct documentation of migratory recovery (i.e., loss of infection during migration) and escape in a wild population. The body temperature reductions that we observed during hibernation warrant further consideration into the role that this period plays in seasonal Bd dynamics. PMID:29761041

Angiotensin II induces water absorption behavior in two species of desert anurans.

PubMed

Propper, C R; Johnson, W E

1994-03-01

The octapeptide, angiotensin II (A-II), induces drinking behavior in several vertebrate species; however, relatively little is understood about A-II-induced thirst in amphibians. Scaphiopus couchii and Bufo cognatus were dehydrated to 90% of their ad libitum weight. This level of dehydration was sufficient to induce water absorption response (WR) behavior in both species. Fully hydrated toads injected intraperitoneally with A-II exhibited a significant amount of WR behavior. The minimum effective dose for inducing WR behavior was 10 micrograms/100 g-animal for S. couchii and 100 micrograms/100 g-animal for B. cognatus. When dehydrated toads were treated with the A-II receptor antagonist, Thr8-saralasin, S. couchii, exhibited a significant increase in WR behavior, while B. cognatus did not respond behaviorally. Finally, treatment of dehydrated toads with captopril, a compound that inhibits conversion of angiotensin I to A-II, did not significantly affect WR behavior in either species. These results support other findings that A-II may be involved in WR behavior in amphibians. However, the failure of Thr2-saralasin or captopril to inhibit WR behavior in dehydrated toads suggests that the receptor mechanisms involved in thirst regulation in toads may be different from those in mammals, and the renin-angiotensin system may not be the only potential mediator of WR behavior in these species.

A novel multilocus phylogenetic estimation reveals unrecognized diversity in Asian horned toads, genus Megophrys sensu lato (Anura: Megophryidae).

PubMed

Chen, Jin-Min; Zhou, Wei-Wei; Poyarkov, Nikolay A; Stuart, Bryan L; Brown, Rafe M; Lathrop, Amy; Wang, Ying-Yong; Yuan, Zhi-Yong; Jiang, Ke; Hou, Mian; Chen, Hong-Man; Suwannapoom, Chatmongkon; Nguyen, Sang Ngoc; Duong, Tang Van; Papenfuss, Theodore J; Murphy, Robert W; Zhang, Ya-Ping; Che, Jing

2017-01-01

The horned toad assemblage, genus Megophrys sensu lato, currently includes three groups previously recognized as the genera Atympanophrys, Xenophrys and Megophrys sensu stricto. The taxonomic status and species composition of the three groups remain controversial due to conflicting phenotypic analyses and insufficient phylogenetic reconstruction; likewise, the position of the monotypic Borneophrys remains uncertain with respect to the horned toads. Further, the diversity of the horned toads remains poorly understood, especially for widespread species. Herein, we evaluate species-level diversity based on 45 of the 57 described species from throughout southern China, Southeast Asia and the Himalayas using Bayesian inference trees and the Generalized Mixed Yule Coalescent (GMYC) approach. We estimate the phylogeny using both mitochondrial and nuclear DNA data. Analyses reveal statistically significant mito-nuclear discordance. All analyses resolve paraphyly for horned toads involving multiple strongly supported clades. These clades correspond with geography. We resurrect the genera Atympanophrys and Xenophrys from the synonymy of Megophrys to eliminate paraphyly of Megophrys s.l. and to account for the morphological, molecular and biogeographic differences among these groups, but we also provide an alternative option. Our study suggests that Borneophrys is junior synonym of Megophrys sensu stricto. We provide an estimation of timeframe for the horned toads. The mitochondrial and nuclear trees indicate the presence of many putative undescribed species. Widespread species, such as Xenophrys major and X. minor, likely have dramatically underestimated diversity. The integration of morphological and molecular evidence can validate this discovery. Montane forest dynamics appear to play a significant role in driving diversification of horned toads. Copyright © 2016 Elsevier Inc. All rights reserved.

36 CFR 71.5 - Golden Eagle Passport.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Golden Eagle Passport. 71.5... RECREATION FEES § 71.5 Golden Eagle Passport. (a) The Golden Eagle Passport is an annual permit, valid on a... Passport shall be $10. The annual Golden Eagle Passport shall be nontransferable and the unlawful use...

36 CFR 71.5 - Golden Eagle Passport.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Golden Eagle Passport. 71.5... RECREATION FEES § 71.5 Golden Eagle Passport. (a) The Golden Eagle Passport is an annual permit, valid on a... Passport shall be $10. The annual Golden Eagle Passport shall be nontransferable and the unlawful use...

36 CFR 71.6 - Golden Age Passport.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Golden Age Passport. 71.6... RECREATION FEES § 71.6 Golden Age Passport. (a) Issuance of the Golden Age Passport: (1) Golden Age Passports... Passport will be issued free of charge upon the presentation of identification or information which attests...

36 CFR 71.5 - Golden Eagle Passport.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Golden Eagle Passport. 71.5... RECREATION FEES § 71.5 Golden Eagle Passport. (a) The Golden Eagle Passport is an annual permit, valid on a... Passport shall be $10. The annual Golden Eagle Passport shall be nontransferable and the unlawful use...

36 CFR 71.5 - Golden Eagle Passport.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Golden Eagle Passport. 71.5... RECREATION FEES § 71.5 Golden Eagle Passport. (a) The Golden Eagle Passport is an annual permit, valid on a... Passport shall be $10. The annual Golden Eagle Passport shall be nontransferable and the unlawful use...

36 CFR 71.6 - Golden Age Passport.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Golden Age Passport. 71.6... RECREATION FEES § 71.6 Golden Age Passport. (a) Issuance of the Golden Age Passport: (1) Golden Age Passports... Passport will be issued free of charge upon the presentation of identification or information which attests...

36 CFR 71.6 - Golden Age Passport.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Golden Age Passport. 71.6... RECREATION FEES § 71.6 Golden Age Passport. (a) Issuance of the Golden Age Passport: (1) Golden Age Passports... Passport will be issued free of charge upon the presentation of identification or information which attests...

36 CFR 71.5 - Golden Eagle Passport.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Golden Eagle Passport. 71.5... RECREATION FEES § 71.5 Golden Eagle Passport. (a) The Golden Eagle Passport is an annual permit, valid on a... Passport shall be $10. The annual Golden Eagle Passport shall be nontransferable and the unlawful use...

36 CFR 71.6 - Golden Age Passport.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Golden Age Passport. 71.6... RECREATION FEES § 71.6 Golden Age Passport. (a) Issuance of the Golden Age Passport: (1) Golden Age Passports... Passport will be issued free of charge upon the presentation of identification or information which attests...

36 CFR 71.6 - Golden Age Passport.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Golden Age Passport. 71.6... RECREATION FEES § 71.6 Golden Age Passport. (a) Issuance of the Golden Age Passport: (1) Golden Age Passports... Passport will be issued free of charge upon the presentation of identification or information which attests...

Corticotropin-releasing factor accelerates metamorphosis in Bufo arenarum: effect on pituitary ACTH and TSH cells.

PubMed

Miranda, L A; Affanni, J M; Paz, D A

2000-04-01

The actions of several neuropeptides as hypothalamic mediators in the regulation of Bufo arenarum metamorphosis were investigated. Prometamorphic larvae were injected with 1.5 microg thyrotropin-releasing hormone (TRH), 2 microg ovine corticotropin-releasing factor (oCRF), 2 microg mammalian gonadotropin-releasing hormone (mGnRH), 2 microg human growth hormone-releasing hormone (hGHRH), or Holtfreter solution (control group). Larvae received two injections with the same dose: one at the beginning of the experiment and the other 7 days later. Several morphologic parameters (total length, tail length, wet weight, hind limb length, and metamorphic stages) were measured as indicators of growth and metamorphic development. These measurements were taken in 20 larvae per treatment or control group at the beginning of the experiment, at day 7 and at day 14 when the experiment ended. We observed that only the administration of exogenous CRF stimulated resorption of the tail and accelerated the rate of metamorphosis. In the pituitary of CRF-treated larvae we observed that thyrotropin (TSH) and adrenocorticotropic hormone (ACTH) producing cells showed a weaker immunoreactivity, a decrease in cell number and a reduction of volume density when compared with normal larvae. In conclusion, the results obtained indicate a possible role for CRF in Bufo arenarum metamorphosis. CRF may regulate interrenal and thyroid activity by acting directly upon TSH and ACTH cells. On the other hand, TRH, GnRH and GHRH were inactive in stimulating growth or metamorphosis of Bufo arenarum. J. Exp. Zool. 286:473-480, 2000. Copyright 2000 Wiley-Liss, Inc.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuracko, K. L.; Parang, M.; Landguth, D. C.

2004-09-13

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

Integrating multiple distribution models to guide conservation efforts of an endangered toad

USGS Publications Warehouse

Treglia, Michael L.; Fisher, Robert N.; Fitzgerald, Lee A.

2015-01-01

Species distribution models are used for numerous purposes such as predicting changes in species’ ranges and identifying biodiversity hotspots. Although implications of distribution models for conservation are often implicit, few studies use these tools explicitly to inform conservation efforts. Herein, we illustrate how multiple distribution models developed using distinct sets of environmental variables can be integrated to aid in identification sites for use in conservation. We focus on the endangered arroyo toad (Anaxyrus californicus), which relies on open, sandy streams and surrounding floodplains in southern California, USA, and northern Baja California, Mexico. Declines of the species are largely attributed to habitat degradation associated with vegetation encroachment, invasive predators, and altered hydrologic regimes. We had three main goals: 1) develop a model of potential habitat for arroyo toads, based on long-term environmental variables and all available locality data; 2) develop a model of the species’ current habitat by incorporating recent remotely-sensed variables and only using recent locality data; and 3) integrate results of both models to identify sites that may be employed in conservation efforts. We used a machine learning technique, Random Forests, to develop the models, focused on riparian zones in southern California. We identified 14.37% and 10.50% of our study area as potential and current habitat for the arroyo toad, respectively. Generally, inclusion of remotely-sensed variables reduced modeled suitability of sites, thus many areas modeled as potential habitat were not modeled as current habitat. We propose such sites could be made suitable for arroyo toads through active management, increasing current habitat by up to 67.02%. Our general approach can be employed to guide conservation efforts of virtually any species with sufficient data necessary to develop appropriate distribution models.

Using spatiotemporal models and distance sampling to map the space use and abundance of newly metamorphosed Western Toads (Anaxyrus boreas)

USGS Publications Warehouse

Chelgren, Nathan D.; Samora, Barbara; Adams, Michael J.; McCreary, Brome

2011-01-01

High variability in abundance, cryptic coloration, and small body size of newly metamorphosed anurans have limited demographic studies of this life-history stage. We used line-transect distance sampling and Bayesian methods to estimate the abundance and spatial distribution of newly metamorphosed Western Toads (Anaxyrus boreas) in terrestrial habitat surrounding a montane lake in central Washington, USA. We completed 154 line-transect surveys from the commencement of metamorphosis (15 September 2009) to the date of first snow accumulation in fall (1 October 2009), and located 543 newly metamorphosed toads. After accounting for variable detection probability associated with the extent of barren habitats, estimates of total surface abundance ranged from a posterior median of 3,880 (95% credible intervals from 2,235 to 12,600) in the first week of sampling to 12,150 (5,543 to 51,670) during the second week of sampling. Numbers of newly metamorphosed toads dropped quickly with increasing distance from the lakeshore in a pattern that differed over the three weeks of the study and contradicted our original hypotheses. Though we hypothesized that the spatial distribution of toads would initially be concentrated near the lake shore and then spread outward from the lake over time, we observed the opposite. Ninety-five percent of individuals occurred within 20, 16, and 15 m of shore during weeks one, two, and three respectively, probably reflecting continued emergence of newly metamorphosed toads from the lake and mortality or burrow use of dispersed individuals. Numbers of toads were highest near the inlet stream of the lake. Distance sampling may provide a useful method for estimating the surface abundance of newly metamorphosed toads and relating their space use to landscape variables despite uncertain and variable probability of detection. We discuss means of improving the precision of estimates of total abundance.

Amphibian embryo and parental defenses and a larval predator reduce egg mortality from water mold.

PubMed

Gomez-Mestre, Ivan; Touchon, Justin C; Warkentin, Karen M

2006-10-01

Water molds attack aquatic eggs worldwide and have been associated with major mortality events in some cases, but typically only in association with additional stressors. We combined field observations and laboratory experiments to study egg stage defenses against pathogenic water mold in three temperate amphibians. Spotted salamanders (Ambystoma maculatum) wrap their eggs in a protective jelly layer that prevents mold from reaching the embryos. Wood frog (Rana sylvatica) egg masses have less jelly but are laid while ponds are still cold and mold growth is slow. American toad (Bufo americanus) eggs experience the highest infection levels. They are surrounded by thin jelly and are laid when ponds have warmed and mold grows rapidly. Eggs of all three species hatched early when infected, yielding smaller and less developed hatchlings. This response was strongest in B. americanus. Precocious hatching increased vulnerability of wood frog hatchlings to invertebrate predators. Finally, despite being potential toad hatchling predators, R. sylvatica tadpoles can have a positive effect on B. americanus eggs. They eat water mold off infected toad clutches, increasing their hatching success.

Analysis of Bufo arenarum oviductal secretion during the sexual cycle.

PubMed

Crespo, Claudia A; Ramos, Inés; Medina, Marcela F; Fernández, Silvia N

2009-11-01

SummaryBufo arenarum oocytes are oviposited surrounded by jelly coats, one component of the extracellular matrix required for fertilization. The secretion, released to the oviductal lumen, was analysed by SDS-PAGE. The coomassie blue staining evidenced an electrophoretic pattern with molecules ranging between 300 and 19 kDa that showed variations in their secretion profiles during the sexual cycle. In the preovulatory period the densitometric analysis showed the presence of nine peaks with marked predominance of the 74 kDa molecule. Once ovulation has occurred, the jelly coats become arranged around the oocytes during their transit throughout the oviductal pars convoluta (PC), revealing the addition of three proteins only observed during this period, which suggests a differential secretion. Some of these proteins could not diffuse under any extraction treatment, indicating for them a structural or in situ function. Proteins of low molecular mass diffused totally while others showed a partial diffusing capacity. After ovulation a marked decrease in the relative amount of all the proteins released to the lumen, especially the 74 kDa protein, could be detected. During this period, unlike the other stages of the sexual cycle, a differential secretion pattern was observed along the PC. The histochemical analysis performed during the ovulatory period showed the presence of glycoconjugates including both acidic and neutral groups. The present results are in agreement with previous ultrastructural and histochemical studies that describe the role of Bufo arenarum jelly coats in fertilization.

Field surveys of Midwestern and Northeastern Fish and Wildlife Service lands for the presence of abnormal frogs and toads

USGS Publications Warehouse

Converse, K.A.; Mattsson, J.; Eaton-Poole, L.

2000-01-01

The national distribution of information on the discovery of malformations in Minnesota frogs in 1995 stimulated collection and examination of newly metamorphosed frogs during 1996. By late summer and early fall of 1996, malformed frogs and toads were reported on U.S. Fish and Wildlife Service (USFWS) lands in Vermont (Northeast, Region 5) and Minnesota (Midwest, Region 3). In response to these reports, biologists in USFWS Regions 3 and 5 conducted a survey, during the summer of 1997 to determine the distribution and type of malformations in frogs and toads on selected federal lands. Region 3 personnel surveyed 38 field stations at National Wildlife Refuges (NWR's) and Wetland Management Districts. Malformed frogs and toads were collected at 23 (61%) of the Region 3 sites. External malformations were detected in 110 of 6632 individuals representing seven of 13 frog species and one of three toad species examined for an overall of 1.7% affected (percentages for affected species ranged from 0.4-5.2%). In Region 5, 17 NWR's and one National Park were surveyed. Malformed frogs were collected at 10 (56%) of the Region 5 sites. External malformations were detected in 58 of 2267 individuals representing six of 11 frog species and one of two toad species examined for an overall total of 2.6% affected (percentages for affected species ranged from 1.8-15.6%). The majority of malformations observed in frogs and toads collected in Regions 3 and 5 were partially or completely missing hind limbs and digits (50%)or malformed hind limbs and digits (14%). A few individuals had an extra limb or toe, missing or malformed front limb, missing eye, or malformation of the mandible. Despite small sample sizes at some sites, malformations were confirmed to be present in eight species of frogs and two species of toads on Federal lands in USFWS Regions 3 and 5. Further study is needed to determine the extent and distribution of amphibian malformations in these Regions. Data from this study

Toxin-resistant isoforms of Na+/K+-ATPase in snakes do not closely track dietary specialization on toads

PubMed Central

Gonzalez, Jonathan; Takeuchi, Hirohiko; Mori, Akira

2016-01-01

Toads are chemically defended by bufadienolides, a class of cardiotonic steroids that exert toxic effects by binding to and disabling the Na+/K+-ATPases of cell membranes. Some predators, including a number of snakes, have evolved resistance to the toxic effects of bufadienolides and prey regularly on toads. Resistance in snakes to the acute effects of these toxins is conferred by at least two amino acid substitutions in the cardiotonic steroid binding pocket of the Na+/K+-ATPase. We surveyed 100 species of snakes from a broad phylogenetic range for the presence or absence of resistance-conferring mutations. We found that such mutations occur in a much wider range of taxa than previously believed. Although all sequenced species known to consume toads exhibited the resistance mutations, many of the species possessing the mutations do not feed on toads, much less specialize on that food source. This suggests that either there is little performance cost associated with these mutations or they provide an unknown benefit. Furthermore, the distribution of the mutation among major clades of advanced snakes suggests that the origin of the mutation reflects evolutionary retention more than dietary constraint. PMID:27852804

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

PubMed

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

2016-11-16

Toads are chemically defended by bufadienolides, a class of cardiotonic steroids that exert toxic effects by binding to and disabling the Na + /K + -ATPases of cell membranes. Some predators, including a number of snakes, have evolved resistance to the toxic effects of bufadienolides and prey regularly on toads. Resistance in snakes to the acute effects of these toxins is conferred by at least two amino acid substitutions in the cardiotonic steroid binding pocket of the Na + /K + -ATPase. We surveyed 100 species of snakes from a broad phylogenetic range for the presence or absence of resistance-conferring mutations. We found that such mutations occur in a much wider range of taxa than previously believed. Although all sequenced species known to consume toads exhibited the resistance mutations, many of the species possessing the mutations do not feed on toads, much less specialize on that food source. This suggests that either there is little performance cost associated with these mutations or they provide an unknown benefit. Furthermore, the distribution of the mutation among major clades of advanced snakes suggests that the origin of the mutation reflects evolutionary retention more than dietary constraint. © 2016 The Author(s).

Modulators of Bufo arenarum ovulation.

PubMed

Ramos, Inés; Cisint, Susana B; Crespo, Claudia A; Medina, Marcela F; Fernández, Silvia N

2008-02-01

In this study we investigated ovulation in vitro using ovary samples from Bufo arenarum with respect to their response to stimulation with homologous pituitary homogenate (HPH) or with progesterone and prostaglandins (PGF2alpha and PGE1) as intermediates of pituitary action. Ovary samples were obtained from animals captured during the breeding period. Our results demonstrate that the ovulatory response to all different inducers was dose dependent, the highest percentage of ovulated oocytes being obtained with HPH treatment. An important increase in the ovulatory response was obtained by the association of PGF2alpha with either HPH or progesterone at suboptimal doses, indicating that this prostaglandin induced a synergistic potentiating effect. Incubation with cyclooxygenase inhibitors (indomethacin or diclofenac sodium) produced a significant decrease in the ovulation induced by HPH, demonstrating that prostaglandins are involved in the action of the pituitary gland in this process. According to our results, PGE1 not only had no participation in the ovulatory process, but also produced an inhibitory effect on ovulation induced by HPH treatment.

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

PubMed

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

2000-10-01

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

Golden Gate Vanpool Demonstration Project

DOT National Transportation Integrated Search

1979-07-01

The report evaluates the Golden Gate Vanpool Demonstration Project activities begun in October 1977. The objective of the demonstration is to successfuly promote commuter ridesharing through vanpools. The project grantee, the Golden Gate Bridge, High...

Finding golden mean in a physics exercise

NASA Astrophysics Data System (ADS)

Benedetto, Elmo

2017-07-01

The golden mean is an algebraic irrational number that has captured the popular imagination and is discussed in many books. Indeed, some scientists believe that it appears in some patterns in nature, including the spiral arrangement of leaves and other plant parts. Generally, the golden mean is introduced in geometry and the textbooks give the definition showing a graphical method to determine it. In this short note, we want to find this number by studying projectile motion. This could be a way to introduce the golden mean (also said to be the golden ratio, golden section, Fidia constant, divine proportion or extreme and mean ratio) in a physics course.

Long-term observations of Boreal Toads at an ARMI apex site

USGS Publications Warehouse

Corn, Paul Stephen; Muths, Erin L.; Pilliod, David S.

2011-01-01

The U.S. Geological Survey’s Amphibian Research and Monitoring Initiative (ARMI) is a national project with goals to monitor the status and trends of amphibians, conduct research on causes of declines, and provide information and support to management agencies for conservation of amphibian populations. ARMI activities are organized around extensive inventories and place-based monitoring (such as collaboration with the Greater Yellowstone Inventory and Monitoring Network), and intensive population studies and research at selected locations (apex sites). One such site is an oxbow pond on the Buffalo Fork near the Black Rock Ranger Station east of Grand Teton National Park. We have been conducting mark-recapture of boreal toads (Anaxyrus boreas) at Black Rock since 2002. In concert with studies of other toad populations in the Rocky Mountains, we have documented a high rate of incidence of the chytrid fungus Batrachochytrium dendrobatidis (Bd) and a negative rate of growth of the toad population, but not the population crash or extinction observed in other populations with high prevalence of Bd. Long-term observations at other ARMI apex sites have proven invaluable for studying effects of climate change on amphibian behavior, and the Black Rock site has been upgraded with onsite recording of weather data and auditory monitoring of other amphibian species. Continued research at Black Rock will be critical for understanding the interrelated effects of climate and disease on amphibians in the Greater Yellowstone Ecosystem.

Why Is Golden Rice Golden (Yellow) Instead of Red?1[w

PubMed Central

Schaub, Patrick; Al-Babili, Salim; Drake, Rachel; Beyer, Peter

2005-01-01

The endosperm of Golden Rice (Oryza sativa) is yellow due to the accumulation of β-carotene (provitamin A) and xanthophylls. The product of the two carotenoid biosynthesis transgenes used in Golden Rice, phytoene synthase (PSY) and the bacterial carotene desaturase (CRTI), is lycopene, which has a red color. The absence of lycopene in Golden Rice shows that the pathway proceeds beyond the transgenic end point and thus that the endogenous pathway must also be acting. By using TaqMan real-time PCR, we show in wild-type rice endosperm the mRNA expression of the relevant carotenoid biosynthetic enzymes encoding phytoene desaturase, ζ-carotene desaturase, carotene cis-trans-isomerase, β-lycopene cyclase, and β-carotene hydroxylase; only PSY mRNA was virtually absent. We show that the transgenic phenotype is not due to up-regulation of expression of the endogenous rice pathway in response to the transgenes, as was suggested to be the case in tomato (Lycopersicon esculentum) fruit, where CRTI expression resulted in a similar carotenoid phenomenon. This means that β-carotene and xanthophyll formation in Golden Rice relies on the activity of constitutively expressed intrinsic rice genes (carotene cis-trans-isomerase, α/β-lycopene cyclase, β-carotene hydroxylase). PSY needs to be supplemented and the need for the CrtI transgene in Golden Rice is presumably due to insufficient activity of the phytoene desaturase and/or ζ-carotene desaturase enzyme in endosperm. The effect of CRTI expression was also investigated in leaves of transgenic rice and Arabidopsis (Arabidopsis thaliana). Here, again, the mRNA levels of intrinsic carotenogenic enzymes remained unaffected; nevertheless, the carotenoid pattern changed, showing a decrease in lutein, while the β-carotene-derived xanthophylls increased. This shift correlated with CRTI-expression and is most likely governed at the enzyme level by lycopene-cis-trans-isomerism. Possible implications are discussed. PMID:15821145

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

PubMed

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

2016-07-01

Foraging modalities (e.g. passive, sit-and-wait, active) and traits are plastic in some species, but the extent to which this plasticity affects interspecific competition remains unclear. Using a long-term laboratory mesocosm experiment, we quantified competition strength and the plasticity of foraging traits in a guild of generalist predators of arthropods with a range of foraging modalities. Each mesocosm contained eight passively foraging pink sundews, and we employed an experimental design where treatments were the presence or absence of a sit-and-wait foraging spider and actively foraging toad crossed with five levels of prey abundance. We hypothesized that actively foraging toads would outcompete the other species at low prey abundance, but that spiders and sundews would exhibit plasticity in foraging traits to compensate for strong competition when prey were limited. Results generally supported our hypotheses. Toads had a greater effect on sundews at low prey abundances, and toad presence caused spiders to locate webs higher above the ground. Additionally, the closer large spider webs were to the ground, the greater the trichome densities produced by sundews. Also, spider webs were larger with than without toads and as sundew numbers increased, and these effects were more prominent as resources became limited. Finally, spiders negatively affected toad growth only at low prey abundance. These findings highlight the long-term importance of foraging modality and plasticity of foraging traits in determining the strength of competition within and across taxonomic kingdoms. Future research should assess whether plasticity in foraging traits helps to maintain coexistence within this guild and whether foraging modality can be used as a trait to reliably predict the strength of competitive interactions. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

Are We Golden?: Investigations with the Golden Ratio

ERIC Educational Resources Information Center

Reeder, Stacy L.

2007-01-01

This article describes an activity in which students investigate the "golden nature" of their bodies through measurement and proportional thinking and make connections between mathematics and their world. (Contains 2 figures.)

Variation of thermal parameters in two different color morphs of a diurnal poison toad, Melanophryniscus rubriventris (Anura: Bufonidae).

PubMed

Sanabria, Eduardo A; Vaira, Marcos; Quiroga, Lorena B; Akmentins, Mauricio S; Pereyra, Laura C

2014-04-01

We study the variation in thermal parameters in two contrasting populations Yungas Redbelly Toads (Melanophryniscus rubriventris) with different discrete color phenotypes comparing field body temperatures, critical thermal maximum and heating rates. We found significant differences in field body temperatures of the different morphs. Temperatures were higher in toads with a high extent of dorsal melanization. No variation was registered in operative temperatures between the study locations at the moment of capture and processing. Critical thermal maximum of toads was positively related with the extent of dorsal melanization. Furthermore, we founded significant differences in heating rates between morphs, where individuals with a high extent of dorsal melanization showed greater heating rates than toads with lower dorsal melanization. The color pattern-thermal parameter relationship observed may influence the activity patterns and body size of individuals. Body temperature is a modulator of physiological and behavioral functions in amphibians, influencing daily and seasonal activity, locomotor performance, digestion rate and growth rate. It is possible that some growth constraints may arise due to the relationship of color pattern-metabolism allowing different morphs to attain similar sizes at different locations instead of body-size clines. Copyright © 2014. Published by Elsevier Ltd.

Multi-constituent identification in Australian cane toad skin extracts using high-performance liquid chromatography high-resolution tandem mass spectrometry.

PubMed

Zulfiker, Abu Hasanat Md; Sohrabi, Mohsen; Qi, Ji; Matthews, Ben; Wei, Ming Q; Grice, I Darren

2016-09-10

Toad skins and venom glandular secretions have been widely used for centuries in traditional Chinese and Japanese medicine for the treatment of various ailments such as cancer, sores, toothache, local inflammation and pain. The active chemical constituents from traditional oriental medicines have demonstrated potential in the development of effective therapeutic pharmaceuticals. Our primary focus in this research was to identify and characterise 'active' compounds or groups of compounds for their potential as neuropsychiatric disorder therapeutics. For this aim, we utilised a variety of solvents, i.e., the aqueous, 60% ethanol (aqueous) and acetic acid (aq) (at two different pHs) for extractions of Australian cane toad skins to identify chemical constituents. The identification of compounds was carried out using HPLC-ESI-Q-TOF-MS/MS based on the accurate mass measurement for molecular ions and MS/MS analysis, whereby accurate mass pseudo-molecular ions and characteristic fragment ions were compared to published reference data, including mass bank and NIST. As a result, we have to date identified 42 major constituents including alkaloids, amino acids, bufadienolides, fatty acids, nucleobases, nucleosides and vitamins mostly from the aqueous and 60% ethanol extracts. Of the 42 constituents identified, 29 were found in the aqueous extract, 35 were found in the ethanol (aq) extract and only 10 in the pH 1.78 acetic acid extract and 11 in the pH 2.17 acetic acid extract of the cane toad skins. Therefore, the aqueous and 60% ethanolic extracts present the greatest potential for ongoing development in our assays. There have been no previous reports on the identification of many of the constituents we have here identified in Australian cane toad skins. These findings, while somewhat consistent with findings in toad skins in other countries, identifies the presence of potential bioactive constituents. Our results showed that HPLC-ESI-Q-TOF-MS/MS is an effective method to

Acute thermal stressor increases glucocorticoid response but minimizes testosterone and locomotor performance in the cane toad (Rhinella marina).

PubMed

Narayan, Edward J; Hero, Jean-Marc

2014-01-01

Climatic warming is a global problem and acute thermal stressor in particular could be considered as a major stressor for wildlife. Cane toads (Rhinella marina) have expanded their range into warmer regions of Australia and they provide a suitable model species to study the sub-lethal impacts of thermal stressor on the endocrine physiology of amphibians. Presently, there is no information to show that exposure to an acute thermal stressor could initiate a physiological stress (glucocorticoid) response and secondly, the possible effects on reproductive hormones and performance. Answering these questions is important for understanding the impacts of extreme temperature on amphibians. In this study, we experimented on cane toads from Queensland, Australia by acclimating them to mildly warm temperature (25°C) and then exposing to acute temperature treatments of 30°, 35° or 40°C (hypothetical acute thermal stressors). We measured acute changes in the stress hormone corticosterone and the reproductive hormone testosterone using standard capture and handling protocol and quantified the metabolites of both hormones non-invasively using urinary enzyme-immunoassays. Furthermore, we measured performance trait (i.e. righting response score) in the control acclimated and the three treatment groups. Corticosterone stress responses increased in all toads during exposure to an acute thermal stressor. Furthermore, exposure to a thermal stressor also decreased testosterone levels in all toads. The duration of the righting response (seconds) was longer for toads that were exposed to 40°C than to 30°, 35° or 25°C. The increased corticosterone stress response with increased intensity of the acute thermal stressor suggests that the toads perceived this treatment as a stressor. Furthermore, the results also highlight a potential trade-off with performance and reproductive hormones. Ultimately, exposure acute thermal stressors due to climatic variability could impact amphibians at

Acute Thermal Stressor Increases Glucocorticoid Response but Minimizes Testosterone and Locomotor Performance in the Cane Toad (Rhinella marina)

PubMed Central

Narayan, Edward J.; Hero, Jean-Marc

2014-01-01

Climatic warming is a global problem and acute thermal stressor in particular could be considered as a major stressor for wildlife. Cane toads (Rhinella marina) have expanded their range into warmer regions of Australia and they provide a suitable model species to study the sub-lethal impacts of thermal stressor on the endocrine physiology of amphibians. Presently, there is no information to show that exposure to an acute thermal stressor could initiate a physiological stress (glucocorticoid) response and secondly, the possible effects on reproductive hormones and performance. Answering these questions is important for understanding the impacts of extreme temperature on amphibians. In this study, we experimented on cane toads from Queensland, Australia by acclimating them to mildly warm temperature (25°C) and then exposing to acute temperature treatments of 30°, 35° or 40°C (hypothetical acute thermal stressors). We measured acute changes in the stress hormone corticosterone and the reproductive hormone testosterone using standard capture and handling protocol and quantified the metabolites of both hormones non-invasively using urinary enzyme-immunoassays. Furthermore, we measured performance trait (i.e. righting response score) in the control acclimated and the three treatment groups. Corticosterone stress responses increased in all toads during exposure to an acute thermal stressor. Furthermore, exposure to a thermal stressor also decreased testosterone levels in all toads. The duration of the righting response (seconds) was longer for toads that were exposed to 40°C than to 30°, 35° or 25°C. The increased corticosterone stress response with increased intensity of the acute thermal stressor suggests that the toads perceived this treatment as a stressor. Furthermore, the results also highlight a potential trade-off with performance and reproductive hormones. Ultimately, exposure acute thermal stressors due to climatic variability could impact amphibians at

Acclimation to low level exposure of copper in Bufo arenarum embryos: linkage of effects to tissue residues.

PubMed

Herkovits, Jorge; Pérez-Coll, Cristina Silvia

2007-06-01

The acclimation possibilities to copper in Bufo arenarum embryos was evaluated by means of three different low level copper exposure conditions during 14 days. By the end of the acclimation period the copper content in control embryos was 1.04 +/- 0.09 microg g(-1) (wet weight) while in all the acclimated embryos a reduction of about 25% of copper was found. Thus copper content could be considered as a biomarker of low level exposure conditions. Batches of 10 embryos (by triplicate) from each acclimation condition were challenged with three different toxic concentrations of copper. As a general pattern, the acclimation protocol to copper exerted a transient beneficial effect on the survival of the Bufo arenarum embryos. The acclimation phenomenon could be related to the selection of pollution tolerant organisms within an adaptive process and therefore the persistence of information within an ecological system following a toxicological stressor.

Misconceptions about the Golden Ratio.

ERIC Educational Resources Information Center

Markowsky, George

1992-01-01

Typically, the mathematical properties concerning the golden ratio are stated correctly, but much of what is presented with respect to the golden ratio in art, architecture, literature, and aesthetics is false or seriously misleading. Discussed here are some of the most commonly repeated misconceptions promulgated, particularly within mathematics…

Polyploidy in the common tree toad Hyla versicolor Le Conte.

PubMed

Wasserman, A O

1970-01-23

A karyotype of the first known naturally occurring anuran polyploid in North America is described. Hyla versicolor, the common tree toad, is tetraploid (2n-->4n=48). Individual chromosmes representing, each set of four of the Hyla versicolor karyotype correspond closely with those of the diploid (2n = 24) Hyla andersonii karyotype.

CAS role in the brain apoptosis of Bufo arenarum induced by cypermethrin.

PubMed

Izaguirre, M F; Vergara, M N; Casco, V H

2006-08-01

CAS might have a key role in the apoptosis induced by toxins, acting as anti-apoptotic factor, stimulating the cellular proliferation and the cell contact stabilization. To start to elucidate their role in the brain apoptosis of Bufo arenarum induced by cypermethrin (CY), the expression patterns of CAS and several cell adhesion molecules (CAMs) were established. Bufo arenarum tadpoles of the control and acute bioassay survival at different doses (39, 156, 625 and 2,500 microg CY/L) and times (24, 48, 72 and 96 h) of CY treatment were fixed in Carnoy, embedded in paraffin and sectioned. CAS and CAMs expression was determined by immunofluorescence and immunohistochemistry, respectively. When the bioassay starts, CAS increases suggesting a proliferative or regenerative effect, but decreases when the doses and/or the biocide exposure time increases, suggesting compromise of the cellular cycle control and trigger of an apoptotic wave. However, these neurotoxic mechanisms should not involve degradation of N-cadherin and alpha-catenin, in contrast of beta-catenin and axonal N-CAM180, at least in the initial apoptotic phase. Additionally, an adhesion compensatory mechanism by N-CAM180 is observed in the neuron cell body. These results suggest a dual role of CAS in the cellular cycle control during the CY-induced apoptosis: induction of cell proliferation and stabilization of the cell-cell junctions by modulating CAMs expression.

Effects of nonindigenous tadpoles on native tadpoles in Florida: Evidence of competition

USGS Publications Warehouse

Smith, Kimberly G.

2005-01-01

The impacts of nonindigenous species on native ecosystems can be severe, sometimes leading to the extinction of native taxa. Interspecific competition is a potential mechanism of negative impact of invasive species, but few studies have conclusively demonstrated competition between native and nonindigenous taxa. In this study I used experimental manipulations to examine the competitive effects of the larvae of two widely introduced anurans, the cane toad, Bufo marinus, and the Cuban treefrog, Osteopilus septentrionalis, on the growth and development of the larvae of two native anurans (the southern toad, Bufo terrestris, and the green treefrog, Hyla cinerea). The presence of O. septentrionalis larvae consistently impacted growth and development of native larvae, resulting in reduced growth rates and delayed metamorphosis of both native species and smaller mass at metamorphosis of B. terrestris. Hyla cinerea larvae transformed at greater body masses when reared with the rapidly transforming nonindigenous species as a result of competitive release. The negative effects of O. septentrionalis on native larvae were generally significant whether native tadpoles were exposed to O. septentrionalis alone or in combination with B. marinus. In contrast, B. marinus tadpoles did not significantly impact the growth or development of either native species. Neither nonindigenous species significantly decreased the survivorship of native larvae, although a trend toward decreased survivorship was evident for H. cinerea. These results suggest that nonindigenous larval anurans may adversely impact native tadpole communities as a result of interspecific competition.

Better late than never: effective air-borne hearing of toads delayed by late maturation of the tympanic middle ear structures.

PubMed

Womack, Molly C; Christensen-Dalsgaard, Jakob; Hoke, Kim L

2016-10-15

Most vertebrates have evolved a tympanic middle ear that enables effective hearing of airborne sound on land. Although inner ears develop during the tadpole stages of toads, tympanic middle ear structures are not complete until months after metamorphosis, potentially limiting the sensitivity of post-metamorphic juveniles to sounds in their environment. We tested the hearing of five species of toads to determine how delayed ear development impairs airborne auditory sensitivity. We performed auditory brainstem recordings to test the hearing of the toads and used micro-computed tomography and histology to relate the development of ear structures to hearing ability. We found a large (14-27 dB) increase in hearing sensitivity from 900 to 2500 Hz over the course of ear development. Thickening of the tympanic annulus cartilage and full ossification of the middle ear bone are associated with increased hearing ability in the final stages of ear maturation. Thus, juvenile toads are at a hearing disadvantage, at least in the high-frequency range, throughout much of their development, because late-forming ear elements are critical to middle ear function at these frequencies. We discuss the potential fitness consequences of late hearing development, although research directly addressing selective pressures on hearing sensitivity across ontogeny is lacking. Given that most vertebrate sensory systems function very early in life, toad tympanic hearing may be a sensory development anomaly. © 2016. Published by The Company of Biologists Ltd.

Golden Laboratories and Offices | NREL

Science.gov Websites

most research laboratories are located at our campus in Golden, Colorado, north of highway I-70 and Renewable Energy Laboratory 15013 Denver West Parkway Golden, CO 80401 303-275-3000 GPS Coordinates 39 your trip. Security Procedures Visitors must check in at the Site Entrance Building. Please see

Outbreak of common midwife toad virus in alpine newts (Mesotriton alpestris cyreni) and common midwife toads (Alytes obstetricans) in northern Spain: a comparative pathological study of an emerging ranavirus.

PubMed

Balseiro, Ana; Dalton, Kevin P; del Cerro, Ana; Márquez, Isabel; Parra, Francisco; Prieto, José M; Casais, R

2010-11-01

This report describes the isolation and characterisation of the common midwife toad virus (CMTV) from juvenile alpine newts (Mesotriton alpestris cyreni) and common midwife toad (CMT) tadpoles (Alytes obstetricans) in the Picos de Europa National Park in Northern Spain in August 2008. A comparative pathological and immunohistochemical study was carried out using anti-CMTV polyclonal serum. In the kidneys, glomeruli had the most severe histological lesions in CMT tadpoles, while both glomeruli and renal tubular epithelial cells exhibited foci of necrosis in juvenile alpine newts. Viral antigens were detected by immunohistochemical labelling mainly in the kidneys of CMT tadpoles and in ganglia of juvenile alpine newts. This is the first report of ranavirus infection in the alpine newt, the second known species to be affected by CMTV in the past 2 years. Copyright © 2009 Elsevier Ltd. All rights reserved.

7 CFR 52.1847 - Colors of golden seedless raisins.

Code of Federal Regulations, 2011 CFR

2011-01-01

... range from yellow or golden to light amber color with a predominating yellow or golden color and that... golden or greenish yellow to light amber wherein the predominating color may be greenish yellow or light... 7 Agriculture 2 2011-01-01 2011-01-01 false Colors of golden seedless raisins. 52.1847 Section 52...

7 CFR 52.1847 - Colors of golden seedless raisins.

Code of Federal Regulations, 2012 CFR

2012-01-01

... range from yellow or golden to light amber color with a predominating yellow or golden color and that... golden or greenish yellow to light amber wherein the predominating color may be greenish yellow or light... 7 Agriculture 2 2012-01-01 2012-01-01 false Colors of golden seedless raisins. 52.1847 Section 52...

Acclimation to Low Level Exposure of Copper in Bufo arenarum Embryos: Linkage of Effects to Tissue Residues

PubMed Central

Herkovits, Jorge; Pérez-Coll, Cristina Silvia

2007-01-01

The acclimation possibilities to copper in Bufo arenarum embryos was evaluated by means of three different low level copper exposure conditions during 14 days. By the end of the acclimation period the copper content in control embryos was 1.04 ± 0.09 μg.g−1 (wet weight) while in all the acclimated embryos a reduction of about 25% of copper was found. Thus copper content could be considered as a biomarker of low level exposure conditions. Batches of 10 embryos (by triplicate) from each acclimation condition were challenged with three different toxic concentrations of copper. As a general pattern, the acclimation protocol to copper exerted a transient beneficial effect on the survival of the Bufo arenarum embryos. The acclimation phenomenon could be related to the selection of pollution tolerant organisms within an adaptive process and therefore the persistence of information within an ecological system following a toxicological stressor. PMID:17617681

Communications: Blood chemistry of laboratory-reared Golden trout

USGS Publications Warehouse

Hunn, Joseph B.; Wiedmeyer, Ray H.; Greer, Ivan E.; Grady, Andrew W.

1992-01-01

Golden trout Oncorhynchus aguabonita obtained from a wild stock as fertilized eggs were reared in the laboratory for 21 months. The laboratory-reared golden trout in our study reached sexual maturity earlier and grew more rapidly than wild golden trout do (according to the scientific literature). Male fish averaged 35.6 cm in total length and 426 g in weight, and females averaged 36.2 cm and 487 g. All golden trout were sexually mature when used for hematological analysis. The hematological profile (hematocrit, red blood cells, white blood cells, and thrombocytes) of golden trout was similar to that reported elsewhere for other trout species. Male and female golden trout did not have significantly different thrombocyte counts; however, the immobilization treatment used on the fish (anesthesia versus a blow to the head) resulted in significant treatment differences in thrombocyte numbers and interaction effect of sex in treatment for hematocrits. Gravid female golden trout had significantly higher plasma protein and calcium levels than did males. The ionic compositions of plasma (sodium, potassium, calcium, magnesium, copper, zinc, iron, and chloride) and gallbladder bile (calcium and chloride) were similar to those reported for other salmonids.

Metamorphosis of two amphibian species after chronic cadmium exposure in outdoor aquatic mesocosms

USGS Publications Warehouse

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

2005-01-01

Amphibian larvae at contaminated sites may experience an alteration of metamorphic traits and survival compared to amphibians in uncontaminated conditions. Effects of chronic cadmium (Cd) exposure on the metamorphosis of American toads (Bufo americanus) and southern leopard frogs (Rana sphenocephala) were determined. The two species were reared separately from shortly after hatching through metamorphosis in outdoor mesocosms (1,325-L polyethylene cattle tanks) that simulated natural ponds and enhanced environmental realism relative to the laboratory. Both species exhibited a decrease in survival with increasing initial nominal aqueous Cd concentration. Cadmium treatment did not influence mass at metamorphosis for either species when survival was included as a covariate, but increased the age at metamorphosis for the American toads. The whole body Cd content of metamorphs increased with aqueous Cd treatment level for both species, and the American toads tended to possess more elevated residues. Cadmium quickly partitioned out of the water column and accumulated in and altered the abundance of the tadpoles' diet. Cadmium-contaminated sites may produce fewer metamorphs, and those that survive will metamorphose later and contain Cd. Interspecific differences in the response variables illustrate the importance of testing multiple species when assessing risk.

Overwintered Bullfrog tadpoles negatively affect Salamanders and Anurans in native amphibian communities

USGS Publications Warehouse

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

2004-01-01

We examined the interactive effects of overwintered Bullfrog (Rana catesbeiana) tadpoles and pond hydroperiod on a community of larval amphibians in outdoor mesocosms including American Toads (Bufo americanus), Southern Leopard Frogs (Rana sphenocephala), and Spotted Salamanders (Ambystoma maculatum) - species within the native range of Bullfrogs. Spotted Salamanders and Southern Leopard Frogs were negatively influenced by the presence of overwintered Bullfrogs. Spotted Salamanders had shorter larval periods and slightly smaller masses at metamorphosis, and Southern Leopard Frogs had smaller masses at metamorphosis when reared with Bullfrogs than without. Presence of overwintered Bullfrogs, however, did not significantly affect American Toads. Longer pond hydroperiods resulted in greater survival, greater size at metamorphosis, longer larval periods, and later time until emergence of the first metamorphs for Southern Leopard Frog tadpoles and Spotted Salamander larvae. Our study demonstrated that overwintered Bullfrog tadpoles can respond to changing pond hydroperiods and can negatively impact metamorphosis of native amphibians.

Egg water from the amphibian Bufo arenarum modulates the ability of homologous sperm to undergo the acrosome reaction in the presence of the vitelline envelope.

PubMed

Krapf, Darío; O'Brien, Emma D; Cabada, Marcelo O; Visconti, Pablo E; Arranz, Silvia E

2009-02-01

Sperm from the toad Bufo arenarum must penetrate the egg jelly before reaching the vitelline envelope (VE), where the acrosome reaction is triggered. When the jelly coat is removed, sperm still bind to the VE, but acrosomal exocytosis is not promoted. Our previous work demonstrated that diffusible substances of the jelly coat, termed "egg water" (EW), triggered capacitation-like changes in B. arenarum sperm, promoting the acquisition of a transient fertilizing capacity. In the present work, we correlated this fertilizing capacity with the ability of the sperm to undergo the acrosome reaction, further substantiating the role of the jelly coat in fertilization. When sperm were exposed to the VE, only those preincubated in EW for 5 or 8 min underwent an increase in the intracellular Ca(2+) concentration ([Ca(2+)](i)), which led to acrosomal exocytosis. Responsiveness to the VE was not acquired on preincubation in EW for 2 or 15 min or in Ringer solution regardless of the preincubation time. In contrast, depletion of intracellular Ca(2+) stores (induced by thapsigargin) promoted [Ca(2+)](i) rise and the acrosome reaction even in sperm that were not exposed to EW. Acrosomal exocytosis was blocked by the presence of Ca(2+) chelators independent of whether a physiological or pharmacological stimulus was used. However, Ni(2+) and mibefradil prevented [Ca(2+)](i) rise and the acrosome reaction of sperm exposed to the VE but not of sperm exposed to thapsigargin. These data suggest that the acrosomal responsiveness of B. arenarum sperm, present during a narrow period, is acquired during EW incubation and involves the modulation of a voltage-dependent Ca(2+) channel.

Beyond the Golden Ratio: A Calculator-Based Investigation.

ERIC Educational Resources Information Center

Glidden, Peter L.

2001-01-01

Describes computation of a continued radical to approximate the golden ratio and presents two well-known geometric interpretations of it. Uses guided-discovery to investigate different repeated radicals to see what values they approximate, the golden-rectangle interpretation of these continued radicals, and the golden-section interpretation. (KHR)

Activation of maturation promoting factor in Bufo arenarum oocytes: injection of mature cytoplasm and germinal vesicle contents.

PubMed

Toranzo, G Sánchez; Bonilla, F; Zelarayán, L; Oterino, J; Bühler, M I

2006-11-01

Although progesterone is the established maturation inducer in amphibians, Bufo arenarum oocytes obtained during the reproductive period (spring-summer) resume meiosis with no need of an exogenous hormonal stimulus if deprived of their enveloping follicle cells, a phenomenon called spontaneous maturation. In this species it is possible to obtain oocytes competent and incompetent to undergo spontaneous maturation according to the seasonal period in which animals are captured. Reinitiation of meiosis is regulated by maturation promoting factor (MPF), a complex of the cyclin-dependent kinase p34cdc2 and cyclin B. Although the function and molecule of MPF are common among species, the formation and activation mechanisms of MPF differ according to species. This study was undertaken to evaluate the presence of pre-MPF in Bufo arenarum oocytes incompetent to mature spontaneously and the effect of the injection of mature cytoplasm or germinal vesicle contents on the resumption of meiosis. The results of our treatment of Bufo arenarum immature oocytes incompetent to mature spontaneously with sodium metavanadate (NaVO3) and dexamethasone (DEX) indicates that these oocytes have a pre-MPF, which activates and induces germinal vesicle breakdown (GVBD) by dephosphorylation on Thr-14/Tyr-15 by cdc25 phosphatase and without cyclin B synthesis. The injection of cytoplasm containing active MPF is sufficient to activate an amplification loop that requires the activation of cdc25 and protein kinase C, the decrease in cAMP levels, and is independent of protein synthesis. However, the injection of germinal vesicle content also induces GVBD in the immature receptor oocyte, a process dependent on protein synthesis but not on cdc25 phosphatase or PKC activity.

A burrowing frog from the late Paleocene of Mongolia uncovers a deep history of spadefoot toads (Pelobatoidea) in East Asia.

PubMed

Chen, Jianye; Bever, Gaberiel S; Yi, Hong-Yu; Norell, Mark A

2016-01-11

Fossils are indispensible in understanding the evolutionary origins of the modern fauna. Crown-group spadefoot toads (Anura: Pelobatoidea) are the best-known fossorial frog clade to inhabit arid environments, with species utilizing a characteristic bony spade on their foot for burrowing. Endemic to the Northern Hemisphere, they are distributed across the Holarctic except East Asia. Here we report a rare fossil of a crown-group spadefoot toad from the late Paleocene of Mongolia. The phylogenetic analysis using both morphological and molecular information recovered this Asian fossil inside the modern North American pelobatoid clade Scaphiopodidae. The presence of a spade and the phylogenetic position of the new fossil frog strongly support its burrowing behavior. The late Paleocene age and other information suggestive of a mild climate cast doubt on the conventional assertion that burrowing evolved as an adaptation to aridity in spadefoot toads. Temporally and geographically, the new fossil provides the earliest record of Scaphiopodidae worldwide, and the only member of the group in Asia. Quantitative biogeographic analysis suggests that Scaphiopodidae, despite originating in North America, dispersed into East Asia via Beringia in the Early Cenozoic. The absence of spadefoot toads in East Asia today is a result of extinction.

Individual variation and repeatability in urinary corticosterone metabolite responses to capture in the cane toad (Rhinella marina).

PubMed

Narayan, Edward J; Molinia, Frank C; Cockrem, John F; Hero, Jean-Marc

2012-01-15

Urinary corticosterone metabolite enzyme-immunoassay (EIA) can be used for the non-invasive assessment of baseline levels and corticosterone responses in amphibians. In this study, urinary corticosterone responses of wild male cane toads (Rhinella marina) to confinement and repeated handling were measured to quantify individual variation in corticosterone responses for the first time in an amphibian species. Urine samples were collected at 0 h in the wild, hourly from 2 to 8 h after transfer into captivity, and again at 12 and 24 h in captivity. Toads were then held in captivity and subjected to the same sampling protocol on three occasions at 14 days intervals to quantify variation in corticosterone metabolite responses within and between toads. Baseline and individual corticosterone metabolite responses in male cane toads were generally consistent, with high statistical repeatabilities for 0 h (r=0.630), 6 h (r=0.793), 12 h (r=0.652) and 24 h (r=0.721) corticosterone metabolite concentrations, and for the total and corrected integrated corticosterone responses (r=0.567, p=0.033; r=0.728, p=0.014 respectively). Urinary corticosterone responses appear to be a stable, repeatable trait within individuals. Corticosterone responses in amphibians can be more readily measured when urine rather than plasma samples are collected, and the protocol established in the current study can now be applied to the study of variation in corticosterone responses in other amphibians. Copyright © 2011 Elsevier Inc. All rights reserved.

Easy facial analysis using the facial golden mask.

PubMed

Kim, Yong-Ha

2007-05-01

For over 2000 years, many artists and scientists have tried to understand or quantify the form of the perfect, ideal, or most beautiful face both in art and in vivo (life). A mathematical relationship has been consistently and repeatedly reported to be present in beautiful things. This particular relationship is the golden ratio. It is a mathematical ratio of 1.618:1 that seems to appear recurrently in beautiful things in nature as well as in other things that are seen as beautiful. Dr. Marquardt made the facial golden mask that contains and includes all of the one-dimensional and two-dimensional geometric golden elements formed from the golden ratio. The purpose of this study is to evaluate the usefulness of the golden facial mask. In 40 cases, the authors applied the facial golden mask to preoperative and postoperative photographs and scored each photograph on a 1 to 5 scale from the perspective of their personal aesthetic views. The score was lower when the facial deformity was severe, whereas it was higher when the face was attractive. Compared with the average scores of facial mask applied photographs and nonapplied photographs using a nonparametric test, statistical significance was not reached (P > 0.05). This implies that the facial golden mask may be used as an analytical tool. The facial golden mask is easy to apply, inexpensive, and relatively objective. Therefore, the authors introduce it as a useful facial analysis.

Livestock Grazing, Golden Trout, and Streams in the Golden Trout Wilderness, California: Impacts and Management Implications

Treesearch

R. Knapp; K. Matthews

1996-01-01

Impacts of livestock grazing on California golden trout Oncorhynchus rnykiss aguabonita and their habitat were studied inside and outside of livestock exclosures in the Golden Trout Wilderness, California. In two consecutive years, the majority of stream physical characteristics showed large differences between grazed and ungrazed areas, and the directions of these...

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

PubMed

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

2005-10-01

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

Egg Water from the Amphibian Bufo arenarum Modulates the Ability of Homologous Sperm to Undergo the Acrosome Reaction in the Presence of the Vitelline Envelope1

PubMed Central

Krapf, Darío; O'Brien, Emma D.; Cabada, Marcelo O.; Visconti, Pablo E.; Arranz, Silvia E.

2008-01-01

Sperm from the toad Bufo arenarum must penetrate the egg jelly before reaching the vitelline envelope (VE), where the acrosome reaction is triggered. When the jelly coat is removed, sperm still bind to the VE, but acrosomal exocytosis is not promoted. Our previous work demonstrated that diffusible substances of the jelly coat, termed “egg water” (EW), triggered capacitation-like changes in B. arenarum sperm, promoting the acquisition of a transient fertilizing capacity. In the present work, we correlated this fertilizing capacity with the ability of the sperm to undergo the acrosome reaction, further substantiating the role of the jelly coat in fertilization. When sperm were exposed to the VE, only those preincubated in EW for 5 or 8 min underwent an increase in the intracellular Ca2+ concentration ([Ca2+]i), which led to acrosomal exocytosis. Responsiveness to the VE was not acquired on preincubation in EW for 2 or 15 min or in Ringer solution regardless of the preincubation time. In contrast, depletion of intracellular Ca2+ stores (induced by thapsigargin) promoted [Ca2+]i rise and the acrosome reaction even in sperm that were not exposed to EW. Acrosomal exocytosis was blocked by the presence of Ca2+ chelators independent of whether a physiological or pharmacological stimulus was used. However, Ni2+ and mibefradil prevented [Ca2+]i rise and the acrosome reaction of sperm exposed to the VE but not of sperm exposed to thapsigargin. These data suggest that the acrosomal responsiveness of B. arenarum sperm, present during a narrow period, is acquired during EW incubation and involves the modulation of a voltage-dependent Ca2+ channel. PMID:18923159

Inhibition of basolateral cAMP permeability in the toad urinary bladder.

PubMed

Boom, A; Golstein, P E; Frerotte, M; Sande, J V; Beauwens, R

2000-10-01

1. The effect of sulphonylurea drugs on hydrosmotic flow across toad urinary bladder epithelium was re-evaluated in the present study. Glibenclamide, added to the basolateral medium, significantly enhanced the osmotic flow induced by low doses of antidiuretic hormone (ADH) or forskolin (FK), while it inhibited the effect of exogenous cyclic adenosine monophosphate (cAMP) or its non-hydrolysable bromo derivative, 8-Br-cAMP, added to the basolateral medium. These opposite effects of glibenclamide on the transepithelial osmotic flow can be explained by a reduction of cAMP permeability across the basolateral membrane of the epithelium. The decrease in cAMP permeability leads, according to the direction of the cAMP gradient, to firstly an enhanced osmotic flow when cAMP is generated intracellularly by addition of ADH and FK, glibenclamide reducing cAMP exit from the cell, and secondly a decreased osmotic flow in response to cAMP (and 8-Br-cAMP) added to the basolateral medium, glibenclamide inhibiting, in this case, their entry into the cell. 2. The demonstration that glibenclamide actually inhibits the basolateral cAMP permeability rests on the fact that firstly it decreases the release of cAMP into the basolateral medium by about 40 %, at each concentration of ADH or forskolin tested, secondly it increases the cAMP content of paired hemibladders incubated in the presence of ADH or FK, when intracellular degradation was prevented by phosphodiesterase inhibition, and thirdly it decreases also the uptake of basolateral 8-Br-[3H]cAMP into paired toad hemibladders. 3. Taken together, the present data demonstrate that glibenclamide inhibits the toad urinary bladder basolateral membrane permeability to cAMP, most probably by a direct interaction with a membrane protein not yet indentified but distinct from the sulphonylurea receptor.

Golden Rice is an effective source of vitamin A.

PubMed

Tang, Guangwen; Qin, Jian; Dolnikowski, Gregory G; Russell, Robert M; Grusak, Michael A

2009-06-01

Genetically engineered "Golden Rice" contains up to 35 microg beta-carotene per gram of rice. It is important to determine the vitamin A equivalency of Golden Rice beta-carotene to project the potential effect of this biofortified grain in rice-consuming populations that commonly exhibit low vitamin A status. The objective was to determine the vitamin A value of intrinsically labeled dietary Golden Rice in humans. Golden Rice plants were grown hydroponically with heavy water (deuterium oxide) to generate deuterium-labeled [2H]beta-carotene in the rice grains. Golden Rice servings of 65-98 g (130-200 g cooked rice) containing 0.99-1.53 mg beta-carotene were fed to 5 healthy adult volunteers (3 women and 2 men) with 10 g butter. A reference dose of [13C10]retinyl acetate (0.4-1.0 mg) in oil was given to each volunteer 1 wk before ingestion of the Golden Rice dose. Blood samples were collected over 36 d. Our results showed that the mean (+/-SD) area under the curve for the total serum response to [2H]retinol was 39.9 +/- 20.7 microg x d after the Golden Rice dose. Compared with that of the [13C10]retinyl acetate reference dose (84.7 +/- 34.6 microg x d), Golden Rice beta-carotene provided 0.24-0.94 mg retinol. Thus, the conversion factor of Golden Rice beta-carotene to retinol is 3.8 +/- 1.7 to 1 with a range of 1.9-6.4 to 1 by weight, or 2.0 +/- 0.9 to 1 with a range of 1.0-3.4 to 1 by moles. Beta-carotene derived from Golden Rice is effectively converted to vitamin A in humans. This trial was registered at clinicaltrials.gov as NCT00680355.

Glycoproteins of the vitelline envelope of Amphibian oocyte: biological and molecular characterization of ZPC component (gp41) in Bufo arenarum.

PubMed

Barisone, Gustavo A; Krapf, Darío; Correa-Fiz, Florencia; Arranz, Silvia E; Cabada, Marcelo O

2007-05-01

The vitelline envelope (VE) participates in sperm-egg interactions during the first steps of fertilization. In Bufo arenarum, this envelope is composed of at least four glycoproteins, with molecular masses of 120, 75, 41, and 38 kDa and molar ratio of 1:1.3:7.4:4.8, respectively. These components were isolated and covalently coupled to silanized glass slides in order to study their sperm-binding capacity. When considering the molar ratio of the glycoproteins in the egg-envelope and assuming that each protein is monovalent for sperm, the assay showed that gp41 and gp38 possess 55 and 25% of total sperm-binding activity. We obtained a full-length cDNA of gp41 (ZPC), comprising a sequence for 486 amino acids, with 43.3% homology with Xenopus laevis ZPC. As in the case of mammalian ZP3 and Xenopus ZPC, Bufo ZPC presented a furin-like (convertase) and a C-terminal transmembrane domain (TMD) reflecting common biosynthetic and secretory pathways. As it was reported for some fishes, we obtained evidence that suggests the presence of more than one zpc gene in Bufo genome, based on different partial cDNA sequences of zpc, Southern blots and two-dimensional SDS-PAGE of deglycosylated egg-envelope components. As far as we are aware, this is the first observation of the presence of different zpc genes in an Amphibian species. Copyright (c) 2006 Wiley-Liss, Inc.

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

PubMed

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

2016-08-01

Chromium discharged in industrial effluents frequently occurs as an environmental pollutant, but the lethal and sub-lethal effects the heavy metal might cause in animals exposed to it have been insufficiently investigated. Selecting the amphibian Duttaphrynus melanostictus, we carried out laboratory tests to investigate the effects of short and long term exposure to hexavalent chromium (Cr(VI)) in both tadpoles and adult toads. The concentrations used were 0.002, 0.02, 0.2, 1.0 and 2.0mg/L, the first three corresponding to field levels. In vitro exposures were also carried out using toad erythrocytes and Cr(VI) concentrations of 0.0015, 0.003, 0.015, 0.03, 0.15mg/L. Mortality, growth retardation, developmental delays and structural aberrations were noted in the metal-treated tadpoles, with increasing incidence corresponding to increase in Cr(VI) level and duration of exposure. Many of the sub-lethal effects were evident with long term exposure to environmentally relevant levels of the toxicant. Changes in selected blood parameters and erythrocyte morphometry were also detected in Cr(VI) exposed toads, indicating anaemic and leucopenic conditions. In the genotoxicity study, DNA damage indicated by comet assay and increased micronuclei frequency, occurred at the low Cr(VI) concentrations tested. The multiple deleterious effects of exposure to chromium signal the need for monitoring and controlling the discharge of chromium to the environment. The dose-dependency and genotoxic effects observed in this widely distributed Asian toad indicates its suitability for monitoring heavy metal pollution in aquatic systems. Copyright © 2016 Elsevier B.V. All rights reserved.

The Divine Ratio and Golden Rectangles.

ERIC Educational Resources Information Center

Cooper, Martin

1982-01-01

The material examines aspects of Fibonacci and Lucas sequences, the generation of the Divine Ratio, and the nature of this ratio in golden rectangles, triangles, and figures made up of golden triangles. It is noted Lucas sequence is formed like Fibonacci but has one and three as the first elements. (Author/MP)

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

Treesearch

Cathryn H. Greenberg; George W. Tanner

2005-01-01

Effective amphibian conservation must consider population and landscape processes, but information at multiple scales is rare. We explore spatial and temporal patterns of breeding and recruitment by eastern spadefoot toads (Scaphiopus holbrookii), using nine years of data from continuous monitoring with drift fences and pitfall traps at eight...

Estradiol and reproduction in the South American toad Rhinella arenarum (Amphibian, Anura).

PubMed

Scaia, María Florencia; Volonteri, María Clara; Czuchlej, Silvia Cristina; Ceballos, Nora Raquel

2018-03-16

Rhinella arenarum is a South American toad with wide geographic distribution. Testes of this toad produce high amount of androgens during the non reproductive season and shift steroid synthesis from androgens to 5α-pregnanedione during the breeding. In addition, plasma estradiol (E 2 ) in males of this species shows seasonal variations but, since testes of R. arenarum do not express aromatase, the source of plasma E 2 remained unknown for several years. However, the Bidder's organ (BO), a structure located at one pole of each testis, is proposed to be the main source of E 2 in male's toads since it expresses several steroidogenic enzymes and is able to produce E 2 from endogenous substrates throughout the year. In addition, there were significant correlations between plasma E 2 and total activity of BO aromatase, and between plasma E 2 and the amount of hormone produced by the BO in vitro. In the toad, apoptosis induced by in vitro treatment with E 2 was mostly detected in spermatocytes during the breeding and in spermatids during the post-reproductive season, suggesting that this steroid has an important role in controlling spermatogenesis. However, in vitro treatment with E 2 had no effect on proliferation. This evidence suggests that the mechanism of action of E 2 on amphibian spermatogenesis is complex and more studies are necessary to fully understand the role of estrogens regulating the balance between cellular proliferation and apoptosis. In addition, in R. arenarum in vitro studies suggested that E 2 has no effect on CypP450c17 protein levels or enzymatic activity, while it reduces 3β-hydroxysteroid dehydrogenase/isomerase (3β-HSD/I) activity during the post reproductive season. As well, E 2 regulates FSHβ mRNA expression all over the year suggesting a down regulation process carried out by this steroid. The effect on LHβ mRNA is dual, since during the reproductive season estradiol increases the expression of LHβ mRNA while in the non

The Golden Ratio--A Contrary Viewpoint

ERIC Educational Resources Information Center

Falbo, Clement

2005-01-01

Many assertions about the occurrence of the golden ratio phi in art, architecture, and nature have been shown to be false, unsupported, or misleading. For instance, we show that the spirals found in sea shells, in particular the "Nautilus pompilius," are not in the shape of the golden ratio, as is often claimed. Some of the most interesting…

Diel movement and habitat use of the golden trout Oncorhynchus mykiss aguabonita in their native habitat on the Golden Trout Wilderness, California

Treesearch

K.R. Matthews

1996-01-01

Abstract.—I used radio transmitters to determine the diel habitat use and movement patterns of California golden trout Oncorhynchus mykiss aquabonita inside and outside cattle exclosures on the South Fork Kern River, Golden Trout Wilderness, California. Twenty-three golden trout were monitored from September 10 to 19, 1993, during 216 diel-tracking hours at four study...

Golden Ratio in a Coupled-Oscillator Problem

ERIC Educational Resources Information Center

Moorman, Crystal M.; Goff, John Eric

2007-01-01

The golden ratio appears in a classical mechanics coupled-oscillator problem that many undergraduates may not solve. Once the symmetry is broken in a more standard problem, the golden ratio appears. Several student exercises arise from the problem considered in this paper.

A Response from Golden Rule to "ETS on 'Golden Rule'".

ERIC Educational Resources Information Center

Rooney, J. Patrick

1987-01-01

This article rebuts comments by G. R. Anrig (1987) on the Settlement Agreement that resolved the racial discrimination suit brought by the Golden Rule Insurance Company against the Educational Testing Service (ETS) and the Illinois Department of Insurance. (TJH)

7 CFR 52.1847 - Colors of golden seedless raisins.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Colors of golden seedless raisins. 52.1847 Section 52... Raisins § 52.1847 Colors of golden seedless raisins. The color of Golden Seedless Raisins is not a factor of quality for the purpose of these grades. The color requirements applicable to the respective color...

Portrait of a small population of boreal toads (anaxyrus boreas)

USGS Publications Warehouse

Muths, E.; Scherer, R. D.

2011-01-01

Much attention has been given to the conservation of small populations, those that are small because of decline, and those that are naturally small. Small populations are of particular interest because ecological theory suggests that they are vulnerable to the deleterious effects of environmental, demographic, and genetic stochasticity as well as natural and human-induced catastrophes. However, testing theory and developing applicable conservation measures for small populations is hampered by sparse data. This lack of information is frequently driven by computational issues with small data sets that can be confounded by the impacts of stressors. We present estimates of demographic parameters from a small population of Boreal Toads (Anaxyrus boreas) that has been surveyed since 2001 by using capturerecapture methods. Estimates of annual adult survival probability are high relative to other Boreal Toad populations, whereas estimates of recruitment rate are low. Despite using simple models, clear patterns emerged from the analyses, suggesting that population size is constrained by low recruitment of adults and is declining slowly. These patterns provide insights that are useful in developing management directions for this small population, and this study serves as an example of the potential for small populations to yield robust and useful information despite sample size constraints. ?? 2011 The Herpetologists' League, Inc.

Portrait of a small population of boreal toads (Anaxyrus boreas)

USGS Publications Warehouse

Muths, Erin; Scherer, Rick D.

2011-01-01

Much attention has been given to the conservation of small populations, those that are small because of decline, and those that are naturally small. Small populations are of particular interest because ecological theory suggests that they are vulnerable to the deleterious effects of environmental, demographic, and genetic stochasticity as well as natural and human-induced catastrophes. However, testing theory and developing applicable conservation measures for small populations is hampered by sparse data. This lack of information is frequently driven by computational issues with small data sets that can be confounded by the impacts of stressors. We present estimates of demographic parameters from a small population of Boreal Toads (Anaxyrus boreas) that has been surveyed since 2001 by using capture-recapture methods. Estimates of annual adult survival probability are high relative to other Boreal Toad populations, whereas estimates of recruitment rate are low. Despite using simple models, clear patterns emerged from the analyses, suggesting that population size is constrained by low recruitment of adults and is declining slowly. These patterns provide insights that are useful in developing management directions for this small population, and this study serves as an example of the potential for small populations to yield robust and useful information despite sample size constraints.

Splenic immunotoxicity in developing cane toads (Rhinella marina) from Bermuda.

PubMed

Fort, Douglas J; Mathis, Michael; Fort, Chelsea E; Fort, Hayley M; Fort, Troy D; Linzey, Donald W; Bacon, Jamie P

2016-10-01

The impacts of contaminated sediment from 2 ponds in Bermuda on immune function in newly metamorphosed cane toads were examined. In the present study, a partial life-cycle experiment exposing Gosner stage 20 cane toad tadpoles to pond sediment and laboratory culture water through metamorphosis and into a juvenile state was performed. A basic immunology battery, including general necropsy, spleen somatic index, spleen white pulp content, splenocyte tissue density, and splenocyte viability, was conducted in newly metamorphosed Rhinella marina exposed to Bermuda freshwater sediment and baseline specimens collected from 2 separate populations in south Texas and south Florida, USA. Immune function was evaluated using a lymphocyte proliferation assay with subset specimens infected with Mycobacterium chelonae. In the Bermuda population exposed to pond sediment, splenocyte tissue density was markedly lower and lymphocyte proliferation substantially less relative to cohorts exposed to control sediment and to the North American populations. Considerable increases in spleen weight and liver and spleen lesions related to M. chelonae infection were recorded in challenged Bermuda R. marina compared with unchallenged specimens. Overall, immune function in Bermuda R. marina was compromised compared with North American mainland R. marina regardless of treatment but more dramatically in specimens exposed to Bermuda pond sediments. Environ Toxicol Chem 2016;35:2604-2612. © 2016 SETAC. © 2016 SETAC.

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

PubMed

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

2013-11-01

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

Fine-scale habitat characteristics related to occupancy of the Yosemite Toad, Anaxyrus canorus

Treesearch

Christina T. Liang; Robert L. Grasso; Julie J. Nelson-Paul; Kim E. Vincent; Amy J. Lind

2017-01-01

Fine-scale habitat information can provide insight into species occupancy and persistence that is not apparent at the landscape-scale. Such information is particularly important for rare species that are experiencing population declines, such as the threatened Yosemite Toad (Anaxyrus canorus). Our study examined differences in physical...

Assessment of Polycyclic Aromatic Hydrocarbon Contamination of Breeding Pools Utilized by the Puerto Rican Crested Toad, Peltophryne lemur

PubMed Central

Gjeltema, Jenessa; Stoskopf, Michael; Shea, Damian; De Voe, Ryan

2012-01-01

Habitat preservation and management may play an important role in the conservation of the Puerto Rican crested toad, Peltophryne lemur, due to this species' small geographic range and declining native wild population. Bioavailable water concentrations of Polycyclic Aromatic Hydrocarbon (PAH) contaminants within breeding pools at 3 sites were established using Passive Sampling Devices (PSDs) and gas chromatography-mass spectrometry (GC/MS). A more diverse population of PAH analytes were found in higher concentrations at the breeding site that allowed direct vehicular access, but calculated risk quotients indicated low risk to toad reproduction associated with the current PAH analyte levels. PMID:23762634

Golden Sections

ERIC Educational Resources Information Center

Stuart, Stephen N.

2006-01-01

In this article, the author states that architects, musicians and other thoughtful people have, since the time of Pythagoras, been fascinated by various harmonious proportions. One, is the visual harmony attributed to Euclid, called "the golden section". He explores this concept in geometries of one, two and three dimensions. He added, that in…

Effect of Phloretin on Water and Solute Movement in the Toad Bladder

PubMed Central

Levine, Sherman; Franki, Nicholas; Hays, Richard M.

1973-01-01

It is generally believed that urea crosses the cell membrane through aqueous channels, and that its movement across the membrane is accelerated in the direction of net water flow (solvent drag effect). The present report presents evidence for a vasopressin-sensitive pathway for the movement of urea, other amides, and certain non-amides, which is independent of water flow. Phloretin, when present at 10-4 M concentration in the medium bathing the luminal surface of the toad bladder, strongly inhibits the movement of urea, acetamide, and propionamide across the toad bladder, both in the absence and presence of vasopressin. The vasopressin-stimulated movement of formaldehyde and thiourea is also reduced. Osmotic water flow, on the other hand, is not affected; nor is the movement of ethanol and ethylene glycol, or the net transport of sodium. On the basis of these studies we would conclude that the movement of many, if not all, solutes across the cell membrane is independent of water flow, and that a vasopressin-sensitive carrier may be involved in the transport of certain solutes across the cell membrane. PMID:4703229

Effects of chlorinated solvents on four species of North American amphibians.

PubMed

McDaniel, T V; Martin, P A; Ross, N; Brown, S; Lesage, S; Pauli, B D

2004-07-01

Tetrachloroethylene (PCE), a dry cleaning and degreasing solvent, can enter groundwater through accidental leaks or spills, and concentrations as high as 75 mg/L have been reported in Canadian aquifers. Amphibians in wetlands receiving contaminated groundwater may be exposed to PCE and its degradation products, but little information is available on the impacts of these compounds on indigenous amphibian species. Acute (96-h static renewal) exposures to PCE and its major degradation products, trichloroethylene (TCE) and cisand trans-dichloroethylene, were conducted on embryos of four North American amphibian species: wood frogs (Rana sylvatica), green frogs (R. clamitans), American toads (Bufo americanus), and spotted salamanders (Ambystoma maculatum). Subsequently, chronic exposures to PCE and TCE were conducted with the larvae of American toads. Both PCE and TCE were teratogenic to amphibian embryos; median effective concentrations (EC50s) for developmental deformities produced by PCE and TCE exposure for wood frogs and green frogs were 12 and 40 mg/L, respectively. Embryonic survivorship, however, was not compromised at these concentrations. American toads were less sensitive; the EC50 for developmental abnormalities was not attained at the highest test concentrations, 45 and 85 mg/L PCE and TCE, respectively. These results are pertinent in assessing the impact of groundwater pollution on an aquifer-fed wetland.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

1987-05-01

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

Indolizidine 239Q and Quinolizidine 275I. Major alkaloids in two Argentinian bufonid toads (Melanophryniscus)

PubMed Central

Daly, John W.; Garraffo, H. Martin; Spande, Thomas F.; Yeh, Herman J. C.; Peltzer, Paola M.; Cacivio, Pedro; Baldo, J. Diego; Faivovich, Julián

2008-01-01

Alkaloid profiles in skin of poison frogs/toads (Dendrobatidae, Mantellidae, Bufonidae, and Myobatrachidae) are highly dependent on diet and hence on the nature of habitat. Extracts of the two species of toads (Melanophryniscus klappenbachi and M. cupreuscapularis) from similar habitats in the Corrientes/Chaco Provinces of Argentina have similar profiles of alkaloids, which differ considerably from profiles from other Melanophryniscus species from Brazil, Uruguay and Argentina. Structures of two major alkaloids 239Q (1) and 275I (2) were determined by mass, FTIR, and NMR spectral analysis as 5Z,9Z-3-(1-hydroxybutyl)-5-propylindolizidine and 6Z,10E-4,6-di(pent-4-enyl) quinolizidine, respectively. A third alkaloid, 249F (3), is postulated to be a homopumiliotoxin with an unprecedented conjugated exocyclic diene moiety. PMID:18848574

Development of the nasal chemosensory organs in two terrestrial anurans: the directly developing frog, Eleutherodactylus coqui (Anura: Leptodactylidae), and the metamorphosing toad, Bufo americanus (Anura: Bufonidae).

PubMed

Jermakowicz, Walter J; Dorsey, David A; Brown, Amy L; Wojciechowski, Karen; Giscombe, Claudette L; Graves, Brent M; Summers, Cliff H; Ten Eyck, Gary R

2004-08-01

Nearly all vertebrates possess an olfactory organ but the vomeronasal organ is a synapomorphy for tetrapods. Nevertheless, it has been lost in several groups of tetrapods, including aquatic and marine animals. The present study examines the development of the olfactory and vomeronasal organs in two terrestrial anurans that exhibit different developmental modes. This study compares the development of the olfactory and vomeronasal organs in metamorphic anurans that exhibit an aquatic larva (Bufo americanus) and directly developing anurans that have eliminated the tadpole (Eleutherodactylus coqui). The olfactory epithelium in larval B. americanus is divided into dorsal and ventral branches in the rostral and mid-nasal regions. The larval olfactory pattern in E. coqui has been eliminated. Ontogeny of the olfactory system in E. coqui embryos starts to vary substantially from the larval pattern around the time of operculum development, the temporal period when the larval stage is hypothesized to have been eliminated. The nasal anatomy of the two frogs does not appear morphologically similar until the late stages of embryogenesis in E. coqui and the terminal portion of metamorphosis in B. americanus. Both species and their respective developing offspring, aquatic tadpoles and terrestrial egg/embryos, possess a vomeronasal organ. The vomeronasal organ develops at mid-embryogenesis in E. coqui and during the middle of the larval period in B. americanus, which is relatively late for neobatrachians. Development of the vomeronasal organ in both frogs is linked to the developmental pattern of the olfactory system. This study supports the hypothesis that the most recent common ancestor of tetrapods possessed a vomeronasal organ and was aquatic, and that the vomeronasal organ was retained in the Amphibia, but lost in some other groups of tetrapods, including aquatic and marine animals. Copyright 2004 Wiley-Liss, Inc.

"The Golden Rule": Only a starting point for quality care.

PubMed

Corazzini, Kirsten N; Lekan-Rutledge, Deborah; Utley-Smith, Queen; Piven, Mary L; Colón-Emeric, Cathleen S; Bailey, Donald; Ammarell, Natalie; Anderson, Ruth A

2005-01-01

The Golden Rule guides people to choose for others what they would choose for themselves. The Golden Rule is often described as 'putting yourself in someone else's shoes', or 'Do unto others as you would have them do unto you'(Baumrin 2004). The viewpoint held in the Golden Rule is noted in all the major world religions and cultures, suggesting that this may be an important moral truth (Cunningham 1998). The Golden Rule underlies acts of kindness, caring, and altruism that go above and beyond "business as usual" or "usual care" (Huang, 2005). As such, this heuristic or 'rule of thumb' has universal appeal and helps guide our behaviors toward the welfare of others. So why question the Golden Rule? Unless used mindfully, any heuristic can be overly-simplistic and lead to unintended, negative consequences.A heuristic is a rule of thumb that people use to simplify potentially overwhelming or complex events. These rules of thumb are largely unconscious, and occur irrespective of training and educational level (Gilovich, Griffin & Kahneman 2002). Rules of thumb, such as the Golden Rule, allow a person to reduce a complex situation to something manageable-e.g., 'when in doubt, do what I would want done'. Because it is a simplifying tool, however, the Golden Rule may lead to inappropriate actions because important factors may be overlooked.In this article we describe "The Golden Rule" as used by administrators, supervisors, charge nurses, and CNAs in case studies of four nursing homes. By describing use of this rule-of-thumb, we aim to challenge nurses in nursing homes to: 1) be mindful of their use of "The Golden Rule" and its impact on staff and residents; and 2) help staff members think through how and why "The Golden Rule" may impact their relationships with staff and residents.

The human heart: application of the golden ratio and angle.

PubMed

Henein, Michael Y; Zhao, Ying; Nicoll, Rachel; Sun, Lin; Khir, Ashraf W; Franklin, Karl; Lindqvist, Per

2011-08-04

The golden ratio, or golden mean, of 1.618 is a proportion known since antiquity to be the most aesthetically pleasing and has been used repeatedly in art and architecture. Both the golden ratio and the allied golden angle of 137.5° have been found within the proportions and angles of the human body and plants. In the human heart we found many applications of the golden ratio and angle, in addition to those previously described. In healthy hearts, vertical and transverse dimensions accord with the golden ratio, irrespective of different absolute dimensions due to ethnicity. In mild heart failure, the ratio of 1.618 was maintained but in end-stage heart failure the ratio significantly reduced. Similarly, in healthy ventricles mitral annulus dimensions accorded with the golden ratio, while in dilated cardiomyopathy and mitral regurgitation patients the ratio had significantly reduced. In healthy patients, both the angles between the mid-luminal axes of the pulmonary trunk and the ascending aorta continuation and between the outflow tract axis and continuation of the inflow tract axis of the right ventricle approximate to the golden angle, although in severe pulmonary hypertension, the angle is significantly increased. Hence the overall cardiac and ventricular dimensions in a normal heart are consistent with the golden ratio and angle, representing optimum pump structure and function efficiency, whereas there is significant deviation in the disease state. These findings could have anatomical, functional and prognostic value as markers of early deviation from normality. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

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

USGS Publications Warehouse

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

2011-01-01

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

An Epigenetic Perspective on the Midwife Toad Experiments of Paul Kammerer (1880-1926).

PubMed

Vargas, Alexander O; Krabichler, Quirin; Guerrero-Bosagna, Carlos

2017-01-01

Paul Kammerer was the most outstanding neo-Lamarckian experimentalist of the early 20th century. He reported spectacular results in the midwife toad, including crosses of environmentally modified toads with normal toads, where acquired traits were inherited in Mendelian fashion. Accusations of fraud generated a great scandal, ending with Kammerer's suicide. Controversy reignited in the 1970s, when journalist Arthur Koestler argued against these accusations. Since then, others have argued that Kammerer's results, even if real, were not groundbreaking and could be explained by somatic plasticity, inadvertent selection, or conventional genetics. More recently, epigenetics has uncovered mechanisms by which inheritance can respond directly to environmental change, inviting a reanalysis of Kammerer's descriptions. Previous arguments for mere somatic plasticity have ignored the description of experiments showing heritable germ line modification. Alleged inadvertent selection associated with egg mortality can be discarded, since mortality decreased in a single generation, upon repeated exposures. The challenging implications did not escape the attention of Kammerer's noted contemporary, William Bateson, but he reacted with disbelief, thus encouraging fraud accusations. Nowadays, formerly puzzling phenomena can be explained by epigenetic mechanisms. Importantly, Kammerer described parent-of-origin effects, an effect of parental sex on dominance. Epigenetic mechanisms underlie these effects in genomic imprinting and experiments of transgenerational epigenetic inheritance. In the early 20th century, researchers had no reason to link them with the inheritance of acquired traits. Thus, the parent-of-origin effects in Kammerer's experiments specifically suggest authenticity. Ultimate proof should come from renewed experimentation. To encourage further research, we present a model of possible epigenetic mechanisms. © 2016 Wiley Periodicals, Inc.

Putative golden proportions as predictors of facial esthetics in adolescents.

PubMed

Kiekens, Rosemie M A; Kuijpers-Jagtman, Anne Marie; van 't Hof, Martin A; van 't Hof, Bep E; Maltha, Jaap C

2008-10-01

In orthodontics, facial esthetics is assumed to be related to golden proportions apparent in the ideal human face. The aim of the study was to analyze the putative relationship between facial esthetics and golden proportions in white adolescents. Seventy-six adult laypeople evaluated sets of photographs of 64 adolescents on a visual analog scale (VAS) from 0 to 100. The facial esthetic value of each subject was calculated as a mean VAS score. Three observers recorded the position of 13 facial landmarks included in 19 putative golden proportions, based on the golden proportions as defined by Ricketts. The proportions and each proportion's deviation from the golden target (1.618) were calculated. This deviation was then related to the VAS scores. Only 4 of the 19 proportions had a significant negative correlation with the VAS scores, indicating that beautiful faces showed less deviation from the golden standard than less beautiful faces. Together, these variables explained only 16% of the variance. Few golden proportions have a significant relationship with facial esthetics in adolescents. The explained variance of these variables is too small to be of clinical importance.

Golden trout habitat selection and movement patterns in degraded and recovering sites within the Golden Trout Wilderness, California

Treesearch

K.R. Matthews

1996-01-01

Abstract.—I used radio transmitters to determine habitat selection and movement patterns of California golden trout Oncorhynchus mykiss aguabonita in two areas defined by their different levels of habitat recovery in the Golden Trout Wilderness, California. Study areas were differentiated by the amount of streamside vegetation (low or high coverage of beaked sedge...

Tubular system volume changes in twitch fibres from toad and rat skeletal muscle assessed by confocal microscopy

PubMed Central

Launikonis, Bradley S; Stephenson, D George

2002-01-01

The volume of the extracellular compartment (tubular system) within intact muscle fibres from cane toad and rat was measured under various conditions using confocal microscopy. Under physiological conditions at rest, the fractional volume of the tubular system (t-sysVol) was 1.38 ± 0.09 % (n = 17), 1.41 ± 0.09 % (n = 12) and 0.83 ± 0.07 % (n = 12) of the total fibre volume in the twitch fibres from toad iliofibularis muscle, rat extensor digitorum longus muscle and rat soleus muscle, respectively. In toad muscle fibres, the t-sysVol decreased by 30 % when the tubular system was fully depolarized and decreased by 15 % when membrane cholesterol was depleted from the tubular system with methyl-β-cyclodextrin but did not change as the sarcomere length was changed from 1.93 to 3.30 μm. There was also an increase by 30 % and a decrease by 25 % in t-sysVol when toad fibres were equilibrated in solutions that were 2.5-fold hypertonic and 50 % hypotonic, respectively. When the changes in total fibre volume were taken into consideration, the t-sysVol expressed as a percentage of the isotonic fibre volume did actually decrease as tonicity increased, revealing that the tubular system in intact fibres cannot be compressed below 0.9 % of the isotonic fibre volume. The results can be explained in terms of forces acting at the level of the tubular wall. These observations have important physiological implications showing that the tubular system is a dynamic membrane structure capable of changing its volume in response to the membrane potential, cholesterol depletion and osmotic stress but not when the sarcomere length is changed in resting muscle. PMID:11790823

7 CFR 301.85-9 - Movement of live golden nematodes.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 5 2013-01-01 2013-01-01 false Movement of live golden nematodes. 301.85-9 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Golden Nematode Quarantine and Regulations § 301.85-9 Movement of live golden nematodes. Regulations requiring a permit for and otherwise...

7 CFR 301.85-9 - Movement of live golden nematodes.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 5 2012-01-01 2012-01-01 false Movement of live golden nematodes. 301.85-9 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Golden Nematode Quarantine and Regulations § 301.85-9 Movement of live golden nematodes. Regulations requiring a permit for and otherwise...

7 CFR 301.85-9 - Movement of live golden nematodes.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 5 2014-01-01 2014-01-01 false Movement of live golden nematodes. 301.85-9 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Golden Nematode Quarantine and Regulations § 301.85-9 Movement of live golden nematodes. Regulations requiring a permit for and otherwise...

7 CFR 301.85-9 - Movement of live golden nematodes.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 5 2011-01-01 2011-01-01 false Movement of live golden nematodes. 301.85-9 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Golden Nematode Quarantine and Regulations § 301.85-9 Movement of live golden nematodes. Regulations requiring a permit for and otherwise...

Assessment of the golden ratio in pleasing smiles.

PubMed

Nikgoo, Arash; Alavi, Kamiar; Alavi, Kavah; Mirfazaelian, Ali

2009-01-01

The golden ratio is a guideline to help harmoniously restore or replace missing teeth. However, this concept is controversial. This study assesses the validity of the golden ratio between the widths of the maxillary anterior teeth in individuals presenting with an attractive/nonattractive smile. A double-stage random cluster sample cross-sectional study included 903 students whose ages ranged from 18 to 30 years and met the inclusion criteria. Image-measurement software was used to assess the perceived mesiodistal widths of the maxillary anterior teeth on scanned photographs. A jury of two dental professionals, a portrait photographer, and a painter, along with the respective subject as the fifth judge, determined the attractiveness of each smile on a visual analog scale. The mean value determined whether an individual was allocated to the attractive or nonattractive smile group. Finally, the prevalence of the golden ratio was investigated in these two groups. Intraobserver correlation coefficient was 0.966. Cochran's chi-square test was used for data analysis. According to the jury, 143 individuals had an attractive smile and 289 had a nonattractive smile. Maxillary central to lateral incisor ratio showed the golden proportion in 50.3% of the students with an attractive smile as compared to 38.1% in the nonattractive smile group (P =.014). However, the golden ratio between the maxillary lateral incisors and the canines existed in only 16.8% of the individuals with an attractive smile as compared to 12.1% in the nonattractive smile group (P =.223). The golden ratio can be useful to achieve esthetic restorations of the maxillary central and lateral incisors. However, the golden ratio between the perceived widths of the maxillary lateral incisors to the canines does not seem to be decisive for an attractive smile and other factors should be considered. © 2009 BY QUINTESSENCE PUBLISHING CO, INC.

7 CFR 301.85-9 - Movement of live golden nematodes.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Movement of live golden nematodes. 301.85-9 Section... Regulations § 301.85-9 Movement of live golden nematodes. Regulations requiring a permit for and otherwise governing the movement of live golden nematodes in interstate or foreign commerce are contained in the...

The Effects of the Toxic Cyanobacterium Limnothrix (Strain AC0243) on Bufo marinus Larvae

PubMed Central

Daniels, Olivia; Fabbro, Larelle; Makiela, Sandrine

2014-01-01

Limnothrix (strain AC0243) is a cyanobacterium, which has only recently been identified as toxin producing. Under laboratory conditions, Bufo marinus larvae were exposed to 100,000 cells mL−1 of Limnothrix (strain AC0243) live cultures for seven days. Histological examinations were conducted post mortem and revealed damage to the notochord, eyes, brain, liver, kidney, pancreas, gastrointestinal tract, and heart. The histopathological results highlight the toxicological impact of this strain, particularly during developmental stages. Toxicological similarities to β-N-Methylamino-l-alanine are discussed. PMID:24662524

Alien mink predation induces prolonged declines in archipelago amphibians

PubMed Central

Ahola, Markus; Nordström, Mikael; Banks, Peter B; Laanetu, Nikolai; Korpimäki, Erkki

2006-01-01

Amphibians are undergoing enigmatic global declines variously attributed to a complex web of anthropogenic forces. Alien predators pose a fundamental threat to biodiversity generally that is predicted to be most acute in island ecosystems. While amphibian eggs and tadpoles are vulnerable to aquatic predators, the effect of predators on adult, reproducing frogs, which most influence amphibian population processes, is unknown. Here, we report on the responses of amphibian populations in the outer Finnish Archipelago to a long-term, large-scale removal of American mink (Mustela vison Schreb.), an invasive predator linked to recent biodiversity loss across Europe. Removal increased both the densities and distribution of common frogs (Rana temporaria L.) but not those of common toads (Bufo bufo L.), which appear to escape mink predation because of their unpalatable skin. Importantly, the largest benefits of mink removal to frog recovery were slow to appear as frogs apparently have a delayed maturation in these harsh environments, which means we must be cautious about reliance upon short-term results. PMID:16720400

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

PubMed

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

2012-12-01

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

Short-circuit current and ionic fluxes in the isolated colonic mucosa of Bufo arenarum.

PubMed

Lew, V L

1970-03-01

1. The unidirectional fluxes of (22)Na, (36)Cl and [(14)C]bicarbonate ions were measured in paired portions of the isolated and short-circuited colonic mucosa of Bufo arenarum, separated from its muscular layer. Pharmacological effects as well as effects of changes in the composition of the nutrient solutions on the electrical parameters of membrane activity (potential difference, short-circuit current and total membrane resistance) are described.2. The net fluxes of both Cl and bicarbonate ions were not significantly different from zero in the absence of electrochemical gradients across the membrane.3. The net Na flux from mucosa to serosa represented a variable proportion of the short-circuit current ranging from 62 to 100%.4. The proportion of membranes with high discrepancies between net Na flux and short-circuit current decreased with the duration of captivity of the toads.5. When Na was entirely replaced by choline in the mucosal bathing solution, the short-circuit current dropped by a variable amount within the range of 64 to 98% of its control values in different membranes. This effect was completely reversible. Similar changes in the serosal solution had no effect.6. The short-circuit current and potential difference were very sensitive to the serosal concentration of bicarbonate ions. In different membranes, 60-100% of the short-circuit current was reversibly abolished by bathing the serosal surface with a bicarbonate-free solution. The mucosal bicarbonate level had no effect on either the potential difference or the short-circuit current. 5 mM bicarbonate in the serosal solution restored at least 50% of the short-circuit control value and full recovery was attained by concentrations near 30 mM bicarbonate.7. Anoxia brought the potential difference and short-circuit current reversibly down to zero in about 50 min.8. Ouabain reduced the short-circuit current up to 80% in about 40 min when present in the serosal solution at a concentration of 10(-4)M. At

Short-circuit current and ionic fluxes in the isolated colonic mucosa of Bufo arenarum

PubMed Central

Lew, V. L.

1970-01-01

1. The unidirectional fluxes of 22Na, 36Cl and [14C]bicarbonate ions were measured in paired portions of the isolated and short-circuited colonic mucosa of Bufo arenarum, separated from its muscular layer. Pharmacological effects as well as effects of changes in the composition of the nutrient solutions on the electrical parameters of membrane activity (potential difference, short-circuit current and total membrane resistance) are described. 2. The net fluxes of both Cl and bicarbonate ions were not significantly different from zero in the absence of electrochemical gradients across the membrane. 3. The net Na flux from mucosa to serosa represented a variable proportion of the short-circuit current ranging from 62 to 100%. 4. The proportion of membranes with high discrepancies between net Na flux and short-circuit current decreased with the duration of captivity of the toads. 5. When Na was entirely replaced by choline in the mucosal bathing solution, the short-circuit current dropped by a variable amount within the range of 64 to 98% of its control values in different membranes. This effect was completely reversible. Similar changes in the serosal solution had no effect. 6. The short-circuit current and potential difference were very sensitive to the serosal concentration of bicarbonate ions. In different membranes, 60-100% of the short-circuit current was reversibly abolished by bathing the serosal surface with a bicarbonate-free solution. The mucosal bicarbonate level had no effect on either the potential difference or the short-circuit current. 5 mM bicarbonate in the serosal solution restored at least 50% of the short-circuit control value and full recovery was attained by concentrations near 30 mM bicarbonate. 7. Anoxia brought the potential difference and short-circuit current reversibly down to zero in about 50 min. 8. Ouabain reduced the short-circuit current up to 80% in about 40 min when present in the serosal solution at a concentration of 10-4 M. At

Turning Points of the Spherical Pendulum and the Golden Ratio

ERIC Educational Resources Information Center

Essen, Hanno; Apazidis, Nicholas

2009-01-01

We study the turning point problem of a spherical pendulum. The special cases of the simple pendulum and the conical pendulum are noted. For simple initial conditions the solution to this problem involves the golden ratio, also called the golden section, or the golden number. This number often appears in mathematics where you least expect it. To…

Alternative Fuels Data Center: Golden Eagle Distributors Inc. to Convert

Science.gov Websites

several years. Golden Eagle will convert all fleet vehicles to CNG in their six branch operations Entire Fleet to CNG Golden Eagle Distributors Inc. to Convert Entire Fleet to CNG to someone by E-mail Share Alternative Fuels Data Center: Golden Eagle Distributors Inc. to Convert Entire Fleet

Mitochondrial lipids in Bufo arenarum full-grown oocytes.

PubMed

Gili, Valeria; Alonso, Telma S

2004-05-01

Both the content and composition of polar and neutral lipids from the mitochondrial fraction of ovarian full-grown Bufo arenarum oocytes were analysed in the present study. Triacylglycerols (TAG) represent 33% of the total lipids, followed by phosphatidylcholine (PC), free fatty acids (FFA) and phosphatidylethanolamine (PE). Diphosphatidylglycerol (DPG) or cardiolipin, a specific component of the inner mitochondrial membrane, represents about 4% of the total lipid content. Palmitic (16:0) and arachidonic (20:4n6) acids are the most abundant fatty acids in PC and PE, respectively. DPG is enriched in fatty acids with carbon chain lengths of 18, the principal component being linoleic acid. In phosphatidylinositol (PI), 20:4n6 and stearic acid (18:0) represent about 72 mol% of the total acyl group level. The main fatty acids in TAG are linoleic (18:2), oleic (18:1), and palmitic acids. The fatty acid composition of FFA and diacylglycerols (DAG) is similar, 16:0 being the most abundant acyl group. PE is the most unsaturated lipid and sphingomyelin (SM) has the lowest unsaturation index.

A "Projective" Test of the Golden Section Hypothesis.

ERIC Educational Resources Information Center

Lee, Chris; Adams-Webber, Jack

1987-01-01

In a projective test of the golden section hypothesis, 24 high school students rated themselves and 10 comic strip characters on basis of 12 bipolar constructs. Overall proportion of cartoon figures which subjects assigned to positive poles of constructs was very close to golden section. (Author/NB)

Phylogeography of the Golden Jackal (Canis aureus) in India

PubMed Central

Yumnam, Bibek; Negi, Tripti; Maldonado, Jesús E.; Fleischer, Robert C.; Jhala, Yadvendradev V.

2015-01-01

The golden jackal (Canis aureus) is one of the most common and widely distributed carnivores in India but phylogeographic studies on the species have been limited across its range. Recent studies have observed absence of mitochondrial (mt) DNA diversity in European populations while some North African populations of golden jackal were found to carry gray wolf (Canis lupus lupaster) mtDNA lineages. In the present study, we sequenced 440 basepairs (bp) of control region (CR) and 412 bp of cytochrome b (cyt b) gene of mtDNA from 62 golden jackals sampled from India (n = 55), Israel (n = 2) and Bulgaria (n = 5), to obtain a total of eighteen haplotypes, comprising sixteen from India and one each from Israel and Bulgaria. Except for three previously described haplotypes represented by one cyt b and one CR haplotype both from India, and one CR haplotype from Bulgaria, all haplotypes identified in this study are new. Genetic diversity was high in golden jackals compared to that reported for other canids in India. Unlike the paraphyletic status of African conspecifics with the gray wolf, the Indian (and other Eurasian) golden jackal clustered in a distinct but shallow monophyletic clade, displaying no evidence of admixture with sympatric and related gray wolf and domestic dog clades in the region. Phylogeographic analyses indicated no clear pattern of genetic structuring of the golden jackal haplotypes and the median joining network revealed a star-shaped polytomy indicative of recent expansion of the species from India. Indian haplotypes were observed to be interior and thus ancestral compared to haplotypes from Europe and Israel, which were peripheral and hence more derived. Molecular tests for demographic expansion confirmed a recent event of expansion of golden jackals in the Indian subcontinent, which can be traced back ~ 37,000 years ago during the late Pleistocene. Our results suggest that golden jackals have had a potentially longer evolutionary history in India

Role of phospholipase A2 pathway in regulating activation of Bufo arenarum oocytes.

PubMed

Ajmat, M T; Bonilla, F; Hermosilla, P C; Zelarayán, L; Bühler, M I

2013-08-01

Transient increases in the concentration of cytosolic Ca(2+) are essential for triggering egg activation events. Increased Ca(2+) results from its rapid release from intracellular stores, mainly mediated by one or both intracellular calcium channels: the inositol trisphosphate receptor (IP3R) and the ryanodine receptor (RyR). Several regulatory pathways that tailor the response of these channels to the specific cell type have been proposed. Among its many modulatory actions, calcium can serve as an activator of a cytosolic phospholipase A(2) (cPLA2), which releases arachidonic acid from phospholipids of the endoplasmic reticulum as well as from the nuclear envelope. Previous studies have suggested that arachidonic acid and/or its metabolites were able to modulate the activity of several ion channels. Based on these findings, we have studied the participation of the phospholipase A(2) (PLA(2)) pathway in the process of Bufo arenarum oocyte activation and the interrelation between any of its metabolites and the ion channels involved in the calcium release from the intracellular reservoirs at fertilization. We found that addition of both melittin, a potent PLA(2) activator, and arachidonic acid, the main PLA(2) reaction metabolite, was able to induce activation events in a bell-shaped manner. Differential regulation of IP3Rs and RyRs by arachidonic acid and its products could explain melittin and arachidonic acid behaviour in Bufo arenarum egg activation. The concerted action of arachidonic acid and/or its metabolites could provide controlled mobilization of calcium from intracellular reservoirs and useful tools for understanding calcium homeostasis in eggs that express both types of receptors.

Multi-component identification and target cell-based screening of potential bioactive compounds in toad venom by UPLC coupled with high-resolution LTQ-Orbitrap MS and high-sensitivity Qtrap MS.

PubMed

Ren, Wei; Han, Lingyu; Luo, Mengyi; Bian, Baolin; Guan, Ming; Yang, Hui; Han, Chao; Li, Na; Li, Tuo; Li, Shilei; Zhang, Yangyang; Zhao, Zhenwen; Zhao, Haiyu

2018-04-28

Traditional Chinese medicines (TCMs) are undoubtedly treasured natural resources for discovering effective medicines in treating and preventing various diseases. However, it is still extremely difficult for screening the bioactive compounds due to the tremendous constituents in TCMs. In this work, the chemical composition of toad venom was comprehensively analyzed using ultra-high performance liquid chromatography (UPLC) coupled with high-resolution LTQ-Orbitrap mass spectrometry and 93 compounds were detected. Among them, 17 constituents were confirmed by standard substances and 8 constituents were detected in toad venom for the first time. Further, a compound database of toad venom containing the fullest compounds was further constructed using UPLC coupled with high-sensitivity Qtrap MS. Then a target cell-based approach for screening potential bioactive compounds from toad venom was developed by analyzing the target cell extracts. The reliability of this method was validated by negative controls and positive controls. In total, 17 components in toad venom were discovered to interact with the target cancer cells. Further, in vitro pharmacological trials were performed to confirm the anti-cancer activity of four of them. The results showed that the six bufogenins and seven bufotoxins detected in our research represented a promising resource to explore bufogenins/bufotoxins-based anticancer agents with low cardiotoxic effect. The target cell-based screening method coupled with the compound database of toad venom constructed by UPLC-Qtrap-MS with high sensitivity provide us a new strategy to rapidly screen and identify the potential bioactive constituents with low content in natural products, which was beneficial for drug discovery from other TCMs. ᅟ Graphical abstract.

Golden Rice--five years on the road--five years to go?

PubMed

Al-Babili, Salim; Beyer, Peter

2005-12-01

Provitamin A accumulates in the grain of Golden Rice as a result of genetic transformation. In developing countries, where vitamin A deficiency prevails, grain from Golden Rice is expected to provide this important micronutrient sustainably through agriculture. Since its original production, the prototype Golden Rice has undergone intense research to increase the provitamin A content, to establish the scientific basis for its carotenoid complement, and to better comply with regulatory requirements. Today, the current focus is on how to get Golden Rice effectively into the hands of farmers, which is a novel avenue for public sector research, carried out with the aid of international research consortia. Additional new research is underway to further increase the nutritional value of Golden Rice.

Effects of internal and external pH on amiloride-blockable Na transport across toad urinary bladder vesicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garty, H.; Civan, E.D.; Civan, M.M.

1985-01-01

The authors have examined the effect of internal and external pH on Na+ transport across toad bladder membrane vesicles. Of the total SSNa uptake measured 0.5-2.0 min after introducing tracer, 80 +/- 4% (mean +/- SE, n = 9) is blocked by the diuretic with a KI of 2 X 10(-8) M. Thus, this amiloride-sensitive flux is mediated by the apical sodium-selective channels. Varying the internal (cytosolic) pH over the physiologic range 7.0-8.0 had no effect on sodium transport; this result suggests that variation of intracellular pH in vivo has no direct apical effect on modulating sodium uptake. On themore » other hand, SSNa was directly and monotonically dependent on external pH. External acidification also reduced the amiloride-sensitive efflux across the walls of the vesicles. This inhibition of 22Na efflux was noted at external Na concentrations of both 0.2 microM and 53 mM. These results are different from those reported with whole toad bladder. A number of possible bases for these differences are considered and discussed. They suggest that the natriferic response induced by mucosal acidification of whole toad urinary bladder appears to operate indirectly through one or more factors, presumably cytosolic, present in whole cells and absent from the vesicles.« less

Golden-Local Information | NREL

Science.gov Websites

trip or for more information. Visit the Denver International Airport site to find: Car rental agencies Lakewood Hampton Inn Denver West/Golden Comfort Suites Table Mountain Inn Denver/Lakewood Fairfield Inn

Effect of sediment settling on controlling golden mussel invasion in water transfer project

NASA Astrophysics Data System (ADS)

Xu, Mengzhen; Wang, Zhaoyin; Bogen, Jim; Pan, Baozhu

2013-04-01

Inter-basin water transfer projects have been widely used to solve uneven distribution of water resources and water shortage in China. Along with the transferring of water resources, golden mussel (Limnoperna fortunei), the filter-collector macro-invertebrate species originating from southern China has also been inadvertently transferred to new aquatic environment, resulting in quick and uncontrolled spread of the species. The golden mussels are invasive by nature and endowed with a strong byssus for attaching onto their habitat, allowing them to easily invade natural and artificial aquatic systems, which was resulted in high-density golden mussel attachment that causes serious bio-fouling. Invasion and bio-fouling by golden mussels in water transfer systems has drawn attention widely because it has resulted in high resistance to water flow, corrosion of pipe walls and even clogging of tunnels, as well as causing water pollution and ecological imbalance in the regions that receive water infested with golden mussels. Field investigation was conducted along the East River, which is the main drinking water resource for Cantong province and Hongkong, China, to study the natural habitats of golden mussels. Surveys of water transfer tunnels which carry water from the East River to several big cities in Cantong province were done to study golden mussel invasion and attachment in tunnels. It is found that in the natural habitat, golden mussels mainly attach to bedrock and bank stones and solid surfaces facing upstream, while no golden mussels are attached on the surfaces facing downstream and suffering sediment deposition. In the water transfer tunnels, golden mussel attachment densities of 40,000 individuals/m2 mainly occurred on the portion of tunnel walls which face downwards and thus avoid sedimentation. An experiment was designed to study the effect of sediment settling on golden mussel attachment. The results showed that settling of fine sediment particles affects

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

PubMed

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

2016-07-22

An on-line comprehensive preparative two-dimensional normal-phase liquid chromatography×reversed-phase liquid chromatography (2D NPLC×RPLC) system was constructed with a newly developed vacuum evaporation assisted adsorption (VEAA) interface, allowing fast removal of NPLC solvent in the vacuum condition and successfully solving the solvent incompatibility problem between NPLC and RPLC. The system achieved on-line solvent exchange within the two dimensions and its performance was illustrated by gram-scale isolation of crude extract from the venom of Bufo bufo gargarizans. Within separation time of ∼20h, 19 compounds were obtained with high purity in a single run. With the VEAA interface, the 2D system exhibited apparent advantages in separation efficiency and automation compared with conventional methods, indicating its promising application in the routine separation process for complicated natural products. Copyright © 2016 Elsevier B.V. All rights reserved.

“The Golden Rule”: Only a starting point for quality care

PubMed Central

Corazzini, Kirsten N.; Lekan-Rutledge, Deborah; Utley-Smith, Queen; Piven, Mary L.; Colón-Emeric, Cathleen S.; Bailey, Donald; Ammarell, Natalie; Anderson, Ruth A.

2006-01-01

The Golden Rule guides people to choose for others what they would choose for themselves. The Golden Rule is often described as ‘putting yourself in someone else's shoes’, or ‘Do unto others as you would have them do unto you’(Baumrin 2004). The viewpoint held in the Golden Rule is noted in all the major world religions and cultures, suggesting that this may be an important moral truth (Cunningham 1998). The Golden Rule underlies acts of kindness, caring, and altruism that go above and beyond “business as usual” or “usual care” (Huang, 2005). As such, this heuristic or ‘rule of thumb’ has universal appeal and helps guide our behaviors toward the welfare of others. So why question the Golden Rule? Unless used mindfully, any heuristic can be overly-simplistic and lead to unintended, negative consequences. A heuristic is a rule of thumb that people use to simplify potentially overwhelming or complex events. These rules of thumb are largely unconscious, and occur irrespective of training and educational level (Gilovich, Griffin & Kahneman 2002). Rules of thumb, such as the Golden Rule, allow a person to reduce a complex situation to something manageable—e.g., ‘when in doubt, do what I would want done’. Because it is a simplifying tool, however, the Golden Rule may lead to inappropriate actions because important factors may be overlooked. In this article we describe “The Golden Rule” as used by administrators, supervisors, charge nurses, and CNAs in case studies of four nursing homes. By describing use of this rule-of-thumb, we aim to challenge nurses in nursing homes to: 1) be mindful of their use of “The Golden Rule” and its impact on staff and residents; and 2) help staff members think through how and why “The Golden Rule” may impact their relationships with staff and residents. PMID:17334452

The Golden Gate National Parks Phytophthora response plan

Treesearch

Alisa Shor; John Doyle; Sharon Farrell; Alison Forrestel; Christa Conforti; Lew Stringer; Terri Thomas; Laura Lee Sims

2017-01-01

In partnership with the California Native Nursery Network, the three agencies of the Golden Gate National Parks (National Park Service, Golden Gate National Parks Conservancy, and Presidio Trust) hosted the Symposium, “Responding to an Expanding Threat: Exotic Phytophthora Species in Native Plant Nurseries, Restoration Plantings, and Wildlands” in...

Comprehensive two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography for analysis of toad skin.

PubMed

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

2017-04-15

An analytical two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography (2D NPLC × RPLC) system was constructed with a newly developed thermal evaporation assisted adsorption (TEAA) interface. This novel TEAA interface with heating temperature above solvent boiling point allowed fast removal of organic NPLC solvent and successfully solved the solvent incompatibility problem between NPLC and RPLC. The system achieved rapid on-line solvent exchange between the two dimensions within a short modulation time of 190 s and was applied in the analysis of an extract from the skin of Bufo bufo gargarizans. This is the first time to realize the on-line comprehensive analysis of a moderate polar natural product by coupling NPLC with reversed phase ultra-high performance liquid chromatography (UHPLC). To be highlighted, with the TEAA interface, the 2D NPLC × RPLC system provided excellent resolution and orthogonality (75.2%), when compared with that of 2D RPLC × RPLC. Copyright © 2017 Elsevier B.V. All rights reserved.

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

PubMed Central

Choi, Jae Kwon

1965-01-01

The absorption of Thorotrast and saccharated iron oxide by the epithelium of the toad urinary bladder was studied by electron microscopy. Whether the toads were hydrated, dehydrated, or given Pitressin, no significant differences in transport of colloidal particles by epithelial cells were observed. This implies that these physiological factors had little effect on the transport of the tracer particles. Tracer particles were encountered in three types of epithelial cells which line the bladder lumen, but most frequently in the mitochondria-rich cells. Tracer materials were incorporated into the cytoplasm of epithelial cells after being adsorbed to the coating layer covering the luminal surface of the cells. In the intermediate stage (1 to 3 hours after introducing tracer) particles were present in small vesicles, tubules, and multivesicular bodies. In the later stages (up to 65 hours), the particles were more commonly seen to be densely packed within large membrane-bounded bodies which were often found near the Golgi region. These large bodies probably were formed by the fusion of small vesicles. Irrespective of the stages of absorption, no particles were found in the intercellular spaces or in the submucosa. Particles apparently did not penetrate the intercellular spaces of the epithelium beyond the level of the tight junction. PMID:14287173

Assessment of facial golden proportions among young Japanese women.

PubMed

Mizumoto, Yasushi; Deguchi, Toshio; Fong, Kelvin W C

2009-08-01

Facial proportions are of interest in orthodontics. The null hypothesis is that there is no difference in golden proportions of the soft-tissue facial balance between Japanese and white women. Facial proportions were assessed by examining photographs of 3 groups of Asian women: group 1, 30 young adult patients with a skeletal Class 1 occlusion; group 2, 30 models; and group 3, 14 popular actresses. Photographic prints or slides were digitized for image analysis. Group 1 subjects had standardized photos taken as part of their treatment. Photos of the subjects in groups 2 and 3 were collected from magazines and other sources and were of varying sizes; therefore, the output image size was not considered. The range of measurement errors was 0.17% to 1.16%. ANOVA was selected because the data set was normally distributed with homogeneous variances. The subjects in the 3 groups showed good total facial proportions. The proportions of the face-height components in group 1 were similar to the golden proportion, which indicated a longer, lower facial height and shorter nose. Group 2 differed from the golden proportion, with a short, lower facial height. Group 3 had golden proportions in all 7 measurements. The proportion of the face width deviated from the golden proportion, indicating a small mouth or wide-set eyes in groups 1 and 2. The null hypothesis was verified in the group 3 actresses in the facial height components. Some measurements in groups 1 and 2 showed different facial proportions that deviated from the golden proportion (ratio).

Ossicular density in golden moles (Chrysochloridae).

PubMed

Mason, Matthew J; Lucas, Sarah J; Wise, Erica R; Stein, Robin S; Duer, Melinda J

2006-12-01

The densities of middle ear ossicles of golden moles (family Chrysochloridae, order Afrosoricida) were measured using the buoyancy method. The internal structure of the malleus was examined by high-resolution computed tomography, and solid-state NMR was used to determine relative phosphorus content. The malleus density of the desert golden mole Eremitalpa granti (2.44 g/cm3) was found to be higher than that reported in the literature for any other terrestrial mammal, whereas the ossicles of other golden mole species are not unusually dense. The increased density in Eremitalpa mallei is apparently related both to a relative paucity of internal vascularization and to a high level of mineralization. This high density is expected to augment inertial bone conduction, used for the detection of seismic vibrations, while limiting the skull modifications needed to accommodate the disproportionately large malleus. The mallei of the two subspecies of E. granti, E. g. granti and E. g. namibensis, were found to differ considerably from one another in both size and shape.

The Golden Ratio: A Golden Opportunity to Investigate Multiple Representations of a Problem.

ERIC Educational Resources Information Center

Dickey, Edwin M.

1993-01-01

This article explores the multiple representations (verbal, algebraic, graphical, and numerical) that can be used to study the golden ratio. Emphasis is placed on using technology (both calculators and computers) to investigate the algebraic, graphical, and numerical representations. (JAF)

Lipids during Bufo arenarum oogenesis.

PubMed

Bruzzone, Ariana; Buschiazzo, Jorgelina; Alonso, Telma S

2003-05-01

The content and composition of phospholipids and triacylglycerols (TAGs) in Bufo arenarum oocytes in stages III and IV of their oogenesis were studied. The total amount of phospholipids in stage IV oocytes is 0.5-fold higher than in stage III oocytes. In both cases, the main phospholipids are phosphatidylcholine (PC) and phosphatidylethanolamine (PE). A striking observation concerns the high level of diphosphatidylglycerol (DPG) in stage III oocytes, which could be indicative of a relatively larger mitochondrial population with respect to other oogenetic stages. A net increase in sphingomyelin content was found during oogenesis. This fact could be related to the role of this phospholipid in the signal transductional pathways. In PC, palmitic (16:0), linoleic (18:2) and oleic (18:1) are the major fatty acids for both types of oocytes, while in PE the main acyl groups are 18:1, 16:0, arachidonic acid (20:4n6) and 18:2. PE is more unsaturated than PC and both phospholipids are more unsaturated in stage III oocytes than in stage IV oocytes. The amount of triacylglycerols is 0.3-fold higher in stage IV oocytes than in stage III oocytes. In both stages, the main fatty acids are 18:2, 18:1 and 16:0. During oogenesis, a significant increase in 18:1 and 18:3n3, and a decrease in 18:2 of TAG were found. The unsaturation index of TAGs from stage IV oocytes is higher than that from stage III oocytes. The TAG increase during oogenesis is consistent with the putative use of these lipids as a source of energy in embryo development.

No evidence for effects of infection with the amphibian chytrid fungus on populations of yellow-bellied toads.

PubMed

Wagner, Norman; Neubeck, Claus; Guicking, Daniela; Finke, Lennart; Wittich, Martin; Weising, Kurt; Geske, Christian; Veith, Michael

2017-02-08

The parasitic chytrid fungus Batrachochytrium dendrobatidis (Bd) can cause the lethal disease chytridiomycosis in amphibians and therefore may play a role in population declines. The yellow-bellied toad Bombina variegata suffered strong declines throughout western and northwestern parts of its range and is therefore listed as highly endangered for Germany and the federal state of Hesse. Whether chytridiomycosis may play a role in the observed local declines of this strictly protected anuran species has never been tested. We investigated 19 Hessian yellow-bellied toad populations for Bd infection rates, conducted capture-mark-recapture studies in 4 of them over 2 to 3 yr, examined survival histories of recaptured infected individuals, and tested whether multi-locus heterozygosity of individuals as well as expected heterozygosity and different environmental variables of populations affect probabilities of Bd infection. Our results show high prevalence of Bd infection in Hessian yellow-bellied toad populations, but although significant decreases in 2 populations could be observed, no causative link to Bd as the reason for this can be established. Mass mortalities or obvious signs of disease in individuals were not observed. Conversely, we show that growth of Bd-infected populations is possible under favorable habitat conditions and that most infected individuals could be recaptured with improved body indices. Neither genetic diversity nor environmental variables appeared to affect Bd infection probabilities. Hence, genetically diverse amphibian specimens and populations may not automatically be less susceptible for Bd infection.

Golden ratio: A subtle regulator in our body and cardiovascular system?

PubMed

Ozturk, Selcuk; Yalta, Kenan; Yetkin, Ertan

2016-11-15

Golden ratio, which is an irrational number and also named as the Greek letter Phi (φ), is defined as the ratio between two lines of unequal length, where the ratio of the lengths of the shorter to the longer is the same as the ratio between the lengths of the longer and the sum of the lengths. The so-called formula is a mathematical ratio and there exist a variety of examples in natural and man-made structures of great beauty. Moreover, golden ratio is expressed throughout the human body in some ways, including digits, uterus, teeth, and cardiovascular system. Although the association of Fibonacci series or golden ratio with systems and organs of human being has not been assessed in depth yet, the mainstream regulation of cardiovascular system seems to be associated with golden ratio. This raises the idea that there might have been a fine and subtle regulator in our body. In this article, we aimed to elaborate the relationship between the existence of golden ratio and the human body and to discuss the golden ratio and its association with cardiovascular system. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

The golden section and American psychology, 1892-1938.

PubMed

Benjafield, John G

2010-01-01

The golden section has been said by many to be the most beautiful proportion. Fechner was the first to investigate it experimentally, and several late-nineteenth- and early-twentieth-century American psychologists followed up on his work. Among these were four prominent names: Lightner Witmer (1867-1956), Edward L. Thorndike (1874-1949), Robert S. Woodworth (1869-1962), and Robert M. Ogden (1877-1959). Why did such well-known psychologists bother with the golden section? In attempting to answer this question we discovered that the golden section was surprisingly well known during this period, not only in psychology but also in advertising and design. It would have been entirely congruent with their stature for prominent psychologists to take an interest in it.

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

PubMed Central

Grismer, L. Lee; Zachariah, Anil; Brown, Rafe M.

2016-01-01

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

Golden Rice is an effective source for vitamin A

USDA-ARS?s Scientific Manuscript database

Genetically engineered "Golden Rice" contains up to 35 ug Beta-carotene per gram of rice. It is important to determine the vitamin A equivalency of Golden Rice Beta-carotene to project the potential effect of this biofortified grain in rice-consuming populations that commonly exhibit low vitamin A s...

Coincident mass extirpation of neotropical amphibians with the emergence of the infectious fungal pathogen Batrachochytrium dendrobatidis

PubMed Central

Cheng, Tina L.; Rovito, Sean M.; Wake, David B.; Vredenburg, Vance T.

2011-01-01

Amphibians highlight the global biodiversity crisis because ∼40% of all amphibian species are currently in decline. Species have disappeared even in protected habitats (e.g., the enigmatic extinction of the golden toad, Bufo periglenes, from Costa Rica). The emergence of a fungal pathogen, Batrachochytrium dendrobatidis (Bd), has been implicated in a number of declines that have occurred in the last decade, but few studies have been able to test retroactively whether Bd emergence was linked to earlier declines and extinctions. We describe a noninvasive PCR sampling technique that detects Bd in formalin-preserved museum specimens. We detected Bd by PCR in 83–90% (n = 38) of samples that were identified as positive by histology. We examined specimens collected before, during, and after major amphibian decline events at established study sites in southern Mexico, Guatemala, and Costa Rica. A pattern of Bd emergence coincident with decline at these localities is revealed—the absence of Bd over multiple years at all localities followed by the concurrent emergence of Bd in various species at each locality during a period of population decline. The geographical and chronological emergence of Bd at these localities also indicates a southbound spread from southern Mexico in the early 1970s to western Guatemala in the 1980s/1990s and to Monteverde, Costa Rica by 1987. We find evidence of a historical “Bd epidemic wave” that began in Mexico and subsequently spread to Central America. We describe a technique that can be used to screen museum specimens from other amphibian decline sites around the world. PMID:21543713

Coincident mass extirpation of neotropical amphibians with the emergence of the infectious fungal pathogen Batrachochytrium dendrobatidis.

PubMed

Cheng, Tina L; Rovito, Sean M; Wake, David B; Vredenburg, Vance T

2011-06-07

Amphibians highlight the global biodiversity crisis because ∼40% of all amphibian species are currently in decline. Species have disappeared even in protected habitats (e.g., the enigmatic extinction of the golden toad, Bufo periglenes, from Costa Rica). The emergence of a fungal pathogen, Batrachochytrium dendrobatidis (Bd), has been implicated in a number of declines that have occurred in the last decade, but few studies have been able to test retroactively whether Bd emergence was linked to earlier declines and extinctions. We describe a noninvasive PCR sampling technique that detects Bd in formalin-preserved museum specimens. We detected Bd by PCR in 83-90% (n = 38) of samples that were identified as positive by histology. We examined specimens collected before, during, and after major amphibian decline events at established study sites in southern Mexico, Guatemala, and Costa Rica. A pattern of Bd emergence coincident with decline at these localities is revealed-the absence of Bd over multiple years at all localities followed by the concurrent emergence of Bd in various species at each locality during a period of population decline. The geographical and chronological emergence of Bd at these localities also indicates a southbound spread from southern Mexico in the early 1970s to western Guatemala in the 1980s/1990s and to Monteverde, Costa Rica by 1987. We find evidence of a historical "Bd epidemic wave" that began in Mexico and subsequently spread to Central America. We describe a technique that can be used to screen museum specimens from other amphibian decline sites around the world.

Telencephalic Neuronal Activation Associated with Spatial Memory in the Terrestrial Toad Rhinella arenarum: Participation of the Medial Pallium during Navigation by Geometry.

PubMed

Sotelo, María Inés; Daneri, M Florencia; Bingman, Verner Peter; Muzio, Rubén N

2016-01-01

Amphibians are central to discussions of vertebrate evolution because they represent the transition from aquatic to terrestrial life, a transition with profound consequences for the selective pressures shaping brain evolution. Spatial navigation is one class of behavior that has attracted the interest of comparative neurobiologists because of the relevance of the medial pallium/hippocampus, yet, surprisingly, in this regard amphibians have been sparsely investigated. In the current study, we trained toads to locate a water goal relying on the boundary geometry of a test environment (Geometry-Only) or boundary geometry coupled with a prominent, visual feature cue (Geometry-Feature). Once learning had been achieved, the animals were given one last training session and their telencephali were processed for c-Fos activation. Compared to control toads exposed to the test environment for the first time, geometry-only toads were found to have increased neuronal labeling in the medial pallium, the presumptive hippocampal homologue, while geometry-feature toads were found to have increased neuronal labeling in the medial, dorsal, and lateral pallia. The data indicate medial pallial participation in guiding navigation by environmental geometry and lateral, and to a lesser extent dorsal, pallial participation in guiding navigation by a prominent visual feature. As such, participation of the medial pallium/hippocampus in spatial cognition appears to be a conserved feature of terrestrial vertebrates even if their life history is still tied to water, a brain-behavior feature seemingly at least as ancient as the evolutionary transition to life on land. © 2016 S. Karger AG, Basel.

77 FR 22185 - Golden Nematode; Removal of Regulated Areas

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-13

..., without change, an interim rule that amended the golden nematode regulations by removing the townships of... that the fields in these two townships are free of golden nematode, and we determined that regulation... the townships of Elba and Byron in Genesee County, NY, from the list of generally infested areas. \\1...

Book Review: Stars (Copyright 1985, Golden Press; New York)

NASA Astrophysics Data System (ADS)

Marigza, R. N., Jr.

2009-06-01

Stars is a part of the Golden Guides collection produced by Golden Press. It is a small 160 page paperback guide to the constellations, the sun, the moon, planets, and other celestial bodies. The book is convenient to carry along wherever you go, making it an easy to access reference material.

Regulation of Phosphorylation of a Specific Protein in Toad-Bladder Membrane by Antidiuretic Hormone and Cyclic AMP, and Its Possible Relationship to Membrane Permeability Changes

PubMed Central

DeLorenzo, Robert J.; Walton, Kenneth G.; Curran, Peter F.; Greengard, Paul

1973-01-01

Phosphorylation of a specific protein was decreased in intact toad bladders by exposure to either antidiuretic hormone or monobutyryl cyclic AMP. The decrease in phosphorylation caused by these agents preceded the change in electrical potential difference (an indicator of the rate of sodium ion transport) observed in response to the same compounds. The addition of cyclic AMP to homogenates of toad bladder led to a decrease in phosphorylation of the same, or a similar, protein. In subcellular fractionation studies, the effect of cyclic AMP on the phosphorylation of this protein was observed in those fractions rich in membrane fragments, but not in the nuclear or cell-sap fractions. These and other results are compatible with the possibility that the regulation by vasopressin and cyclic AMP of sodium and/or water transport in toad bladder may be mediated through regulation of the phosphorylation of this specific protein. Images PMID:4351809

Characterizing Golden Eagle risk to lead and anticoagulant rodenticide exposure: A review

USGS Publications Warehouse

Herring, Garth; Eagles-Smith, Collin A.; Buck, Jeremy A.

2017-01-01

Contaminant exposure is among the many threats to Golden Eagle (Aquila chrysaetos) populations throughout North America, particularly lead poisoning and anticoagulant rodenticides (AR). These threats may act in concert with others (e.g., lead poisoning and trauma associated with striking objects) to exacerbate risk. Golden Eagles are skilled hunters but also exploit scavenging opportunities, making them particularly susceptible to contaminant exposure from ingesting tissues of poisoned or shot animals. Lead poisoning has long been recognized as an important source of mortality for Golden Eagles throughout North America. More recently, ARs have been associated with both sublethal and lethal effects in raptor species worldwide. In this review, we examine the current state of knowledge for lead and AR exposure in Golden Eagles, drawing from the broader raptor contaminant ecology literature. We examine lead and AR sources within Golden Eagle habitats, exposure routes and toxicity, effects on individuals and populations, synergistic effects, and data and information needs. Continued research addressing data needs and information gaps will help with Golden Eagle conservation planning.

Molecular architecture of silk fibroin of Indian golden silkmoth, Antheraea assama.

PubMed

Gupta, Adarsh K; Mita, Kazuei; Arunkumar, Kallare P; Nagaraju, Javaregowda

2015-08-03

The golden silk spun by Indian golden silkmoth Antheraea assama, is regarded for its shimmering golden luster, tenacity and value as biomaterial. This report describes the gene coding for golden silk H-fibroin (AaFhc), its expression, full-length sequence and structurally important motifs discerning the underlying genetic and biochemical factors responsible for its much sought-after properties. The coding region, with biased isocodons, encodes highly repetitious crystalline core, flanked by a pair of 5' and 3' non-repetitious ends. AaFhc mRNA expression is strictly territorial, confined to the posterior silk gland, encoding a protein of size 230 kDa, which makes homodimers making the elementary structural units of the fibrous core of the golden silk. Characteristic polyalanine repeats that make tight β-sheet crystals alternate with non-polyalanine repeats that make less orderly antiparallel β-sheets, β-turns and partial α-helices. Phylogenetic analysis of the conserved N-terminal amorphous motif and the comparative analysis of the crystalline region with other saturniid H-fibroins reveal that AaFhc has longer, numerous and relatively uniform repeat motifs with lower serine content that assume tighter β-crystals and denser packing, which are speculated to be responsible for its acclaimed properties of higher tensile strength and higher refractive index responsible for golden luster.

Four-Dimensional Golden Search

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fenimore, Edward E.

2015-02-25

The Golden search technique is a method to search a multiple-dimension space to find the minimum. It basically subdivides the possible ranges of parameters until it brackets, to within an arbitrarily small distance, the minimum. It has the advantages that (1) the function to be minimized can be non-linear, (2) it does not require derivatives of the function, (3) the convergence criterion does not depend on the magnitude of the function. Thus, if the function is a goodness of fit parameter such as chi-square, the convergence does not depend on the noise being correctly estimated or the function correctly followingmore » the chi-square statistic. And, (4) the convergence criterion does not depend on the shape of the function. Thus, long shallow surfaces can be searched without the problem of premature convergence. As with many methods, the Golden search technique can be confused by surfaces with multiple minima.« less

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

PubMed Central

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

2011-01-01

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

10Gbit/s all-optical NRZ to RZ conversion based on TOAD

NASA Astrophysics Data System (ADS)

Yan, Yumei; Yin, Lina; Zhou, Yunfeng; Liu, Guoming; Wu, Jian; Lin, Jintong

2006-01-01

Future network will include wavelength division multiplexing (WDM) and optical time division multiplexing (OTDM) technologies. All-optical format conversion between their respective preferable data formats, non-return-to-zero (NRZ) and return-to-zero (RZ), may become an important technology. In this paper, 10Gbit/s all-optical NRZ-to-RZ conversion is demonstrated based on terahertz optical asymmetric demultiplexer (TOAD) using clock all-optically recovered from the NRZ signal for the first time. The clock component is enhanced in an SOA and the pseudo-return-to-zero (PRZ) signal is filtered. The PRZ signal is input into an injection mode-locked fiber ring laser for clock recovery. The recovered clock and the NRZ signal are input into TOAD as pump signal and probe signal, respectively, and format conversion is performed. The quality of the converted RZ signal is determined by that of the recovered clock and the NRZ signal, whereas hardly influenced by gain recovery time of the SOA. In the experimental demonstration, the obtained RZ signal has an extinction ratio of 8.7dB and low pattern dependency. After conversion, the spectrum broadens obviously and shows multimode structure with spectrum interval of 0.08nm, which matches with the bit rate 10Gbit/s. Furthermore, this format conversion method has some tolerance on the pattern dependency of the clock signal.

The complex evolutionary history of the tympanic middle ear in frogs and toads (Anura)

PubMed Central

Pereyra, Martín O.; Womack, Molly C.; Barrionuevo, J. Sebastián; Blotto, Boris L.; Baldo, Diego; Targino, Mariane; Ospina-Sarria, Jhon Jairo; Guayasamin, Juan M.; Coloma, Luis A.; Hoke, Kim L.; Grant, Taran; Faivovich, Julián

2016-01-01

Most anurans possess a tympanic middle ear (TME) that transmits sound waves to the inner ear; however, numerous species lack some or all TME components. To understand the evolution of these structures, we undertook a comprehensive assessment of their occurrence across anurans and performed ancestral character state reconstructions. Our analysis indicates that the TME was completely lost at least 38 independent times in Anura. The inferred evolutionary history of the TME is exceptionally complex in true toads (Bufonidae), where it was lost in the most recent common ancestor, preceding a radiation of >150 earless species. Following that initial loss, independent regains of some or all TME structures were inferred within two minor clades and in a radiation of >400 species. The reappearance of the TME in the latter clade was followed by at least 10 losses of the entire TME. The many losses and gains of the TME in anurans is unparalleled among tetrapods. Our results show that anurans, and especially bufonid toads, are an excellent model to study the behavioural correlates of earlessness, extratympanic sound pathways, and the genetic and developmental mechanisms that underlie the morphogenesis of TME structures. PMID:27677839

The complex evolutionary history of the tympanic middle ear in frogs and toads (Anura).

PubMed

Pereyra, Martín O; Womack, Molly C; Barrionuevo, J Sebastián; Blotto, Boris L; Baldo, Diego; Targino, Mariane; Ospina-Sarria, Jhon Jairo; Guayasamin, Juan M; Coloma, Luis A; Hoke, Kim L; Grant, Taran; Faivovich, Julián

2016-09-28

Most anurans possess a tympanic middle ear (TME) that transmits sound waves to the inner ear; however, numerous species lack some or all TME components. To understand the evolution of these structures, we undertook a comprehensive assessment of their occurrence across anurans and performed ancestral character state reconstructions. Our analysis indicates that the TME was completely lost at least 38 independent times in Anura. The inferred evolutionary history of the TME is exceptionally complex in true toads (Bufonidae), where it was lost in the most recent common ancestor, preceding a radiation of >150 earless species. Following that initial loss, independent regains of some or all TME structures were inferred within two minor clades and in a radiation of >400 species. The reappearance of the TME in the latter clade was followed by at least 10 losses of the entire TME. The many losses and gains of the TME in anurans is unparalleled among tetrapods. Our results show that anurans, and especially bufonid toads, are an excellent model to study the behavioural correlates of earlessness, extratympanic sound pathways, and the genetic and developmental mechanisms that underlie the morphogenesis of TME structures.

Metabolomics method based on ultra high performance liquid chromatography with time-of-flight mass spectrometry to analyze toxins in fresh and dried toad venom.

PubMed

Ma, Hongyue; Niu, Huixia; Cao, Qin; Zhou, Jing; Gong, Yan; Zhu, Zhenhua; Lv, Xiang; Di, Liuqing; Qian, Dawei; Wu, Qinan; Duan, Jin'ao

2016-12-01

Drying is a critical step to prolong the storage time in natural medicine processing but it changes the chemical characteristics of the product. In this study, research was performed to characterize the metabolomic changes in toad venom induced by vacuum-drying at 60°C and air-drying at room temperature by ultra high performance liquid chromatography coupled with pattern recognition approaches. In total 52 metabolites, down-regulated or up-regulated, were identified as potential chemical markers. Compared with fresh toad venom, vacuum-drying at 60°C succeeded in raising the conjugated-type bufadienolide content significantly, while the content of free-type bufadienolides were slightly reduced. On the other hand, toad venom air-dried at room temperature presented a relatively low amount of bufadienolides compared with fresh venom. For example, the content of several known anti-tumor components (gamabufotalin, bufotalin, cinobufagin, etc.) were significantly reduced. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide bioassay further showed that venom air-dried at room temperature had weaker anti-tumor activity on human hepatocellular carcinoma SMMC-7721 proliferation in vitro than samples vacuum-dried at 60°C. These results showed that the great metabolomic changes of toad venom occurred during the drying process, suggesting that a proper drying procedure is important for sustaining the chemical quality of natural medicines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ground sounds: Seismic detection in the golden mole

NASA Astrophysics Data System (ADS)

Narins, Peter M.; Lewis, Edwin R.

2004-05-01

The Namib Desert golden mole is a nocturnal, surface-foraging mammal, possessing a massively hypertrophied malleus which presumably confers low-frequency, substrate-vibration sensitivity through inertial bone conduction. Foraging trails are punctuated with characteristic sand disturbances in which the animal's head dips under the sand. The function of this behavior is not known but it is thought that it may be used to obtain a seismic fix on the next mound to be visited. To test this, we measured the local seismic vibrations both on the top of a mound and on the flats. The spectrum recorded on the flats shows a relatively low-amplitude peak at about 120 Hz, whereas the spectral peak recorded from the mound is nearly 17 dB greater in amplitude and centered at 310 Hz. This suggests that mounds act as seismic beacons for the golden moles that would be detectable from distances corresponding to typical intermound distances of 20-25 m. In addition, out of the 117 species for which data are available, these golden moles have the greatest ossicular mass relative to body size (Mason, personal communication). Functionally, they appear to be low-frequency specialists, and it is likely that golden moles hear through substrate conduction. [Work supported by NIH.

7 CFR 52.1847 - Colors of golden seedless raisins.

Code of Federal Regulations, 2014 CFR

2014-01-01

... raisins are practically uniform in color and may range from yellow or golden to light amber color with a... uniform in color and may range from yellow or golden or greenish yellow to light amber wherein the predominating color may be greenish yellow or light amber and that not more than 3 percent, by weight, of all...

7 CFR 52.1847 - Colors of golden seedless raisins.

Code of Federal Regulations, 2013 CFR

2013-01-01

... raisins are practically uniform in color and may range from yellow or golden to light amber color with a... uniform in color and may range from yellow or golden or greenish yellow to light amber wherein the predominating color may be greenish yellow or light amber and that not more than 3 percent, by weight, of all...

Whooping crane preyed upon by golden eagle

USGS Publications Warehouse

Windingstad, Ronald M.; Stiles, Harry E.; Drewien, Roderick C.

1981-01-01

The Golden Eagle (Aquila chrysaetos) is the largest predatory bird in North America and is well known for its predatory abilities. Attacks have been reported on mammals such as whitetail jackrabbits (Lepus townsendi) (McGahan 1967, J. Wildl. Mgmt. 31: 496), pronghorn antelope (Antilocapra americana) (Bruhns 1970, Can. Field-Natur. 84: 301), Mallards (Anas platyrhynchos) (Kelleher and O'Malia 1971, Auk 88: 186), and Great Blue Herons (Ardea herodias) (Carnie 1954, Condor 56: 3). This communication describes an attack on an immature Whooping Crane (Grus americana) by a Golden Eagle and the subsequent necropsy findings.

Marquardt’s Facial Golden Decagon Mask and Its Fitness with South Indian Facial Traits

PubMed Central

Gandikota, Chandra Sekhar; Yadagiri, Poornima K; Manne, Ranjit; Juvvadi, Shubhaker Rao; Farah, Tamkeen; Vattipelli, Shilpa; Gumbelli, Sangeetha

2016-01-01

Introduction The mathematical ratio of 1:1.618 which is famously known as golden ratio seems to appear recurrently in beautiful things in nature as well as in other things that are seen as beautiful. Dr. Marquardt developed a facial golden mask that contains and includes all of the one-dimensional and two-dimensional geometric golden elements formed from the golden ratio and he claimed that beauty is universal, beautiful faces conforms to the facial golden mask regardless of sex and race. Aim The purpose of this study was to evaluate the goodness of fit of the golden facial mask with the South Indian facial traits. Materials and Methods A total of 150 subjects (75 males & 75 females) with attractive faces were selected with cephalometric orthodontic standards of a skeletal class I relation. The facial aesthetics was confirmed by the aesthetic evaluation of the frontal photographs of the subjects by a panel of ten evaluators including five orthodontists and five maxillofacial surgeons. The well-proportioned photographs were superimposed with the Golden mask along the reference lines, to evaluate the goodness of fit. Results South Indian males and females invariably show a wider inter-zygomatic and inter-gonial width than the golden mask. Most of the South Indian females and males show decreased mid-facial height compared to the golden mask, while the total facial height is more or less equal to the golden mask. Conclusion Ethnic or individual discrepancies cannot be totally ignored as in our study the mask did not fit exactly with the South Indian facial traits but, the beauty ratios came closer to those of the mask. To overcome this difficulty, there is a need to develop variants of golden facial mask for different ethnic groups. PMID:27190951

Estimating site occupancy rates when detection probabilities are less than one

USGS Publications Warehouse

MacKenzie, D.I.; Nichols, J.D.; Lachman, G.B.; Droege, S.; Royle, J. Andrew; Langtimm, C.A.

2002-01-01

Nondetection of a species at a site does not imply that the species is absent unless the probability of detection is 1. We propose a model and likelihood-based method for estimating site occupancy rates when detection probabilities are 0.3). We estimated site occupancy rates for two anuran species at 32 wetland sites in Maryland, USA, from data collected during 2000 as part of an amphibian monitoring program, Frogwatch USA. Site occupancy rates were estimated as 0.49 for American toads (Bufo americanus), a 44% increase over the proportion of sites at which they were actually observed, and as 0.85 for spring peepers (Pseudacris crucifer), slightly above the observed proportion of 0.83.

The Golden bypass landslide, Golden, Colorado

USGS Publications Warehouse

Highland, L.M.; Brown, W. M.

1993-01-01

Slope instability along a new highway bypass in Golden, Colorado, became a major concern in 1993. Rains and snowmelt accelerated movement of a landslide that had begun to develop before the bypass was opened to traffic in July of 1991. The downslope movement of earth materials increased significantly in 1993. During the first few months of the year, the landslide pushed onto the west shoulder of the road and crumpled the pavement beneath the south-bound lane. As we prepare this article (September, 1993), the slide continues to encroach onto the highway, posing a persistent problem despite repeated efforts to slow or stop its movement. As this article will show, permanent solutions to landslide problems of this kind are difficult to obtain. 

Incorporation of Tritium-labelled Thymidine in Bufo $female$ × Rana temporaria $male$ Hybrid Embryos

DOE Office of Scientific and Technical Information (OSTI.GOV)

TENCER, B.

1961-04-01

Two-cell stages of hybrid embryos resulting from the cross-fertilization of Bufo and Rana temporaria were incubated for 17 hrs in a medium containing tritium-labeled thymidine. The embryos were fixed by freeze-substitution and the incorporation of tritium studied by the radioautographic technique. The embryos stopped development at the late blastula stage. Labeling of desoxyribonucleic acid was demonstrated in morula as well as in blastula cells of the lethal hybrids. Tritium-labeled thymidine was shown to be incorporated into desoxyribonucleic acid 24 hr after development stopped, which suggests that the block in development was not due to the arrest of desoxyribonucleic acid synthesis.more » (C.H.)« less

More than a golden hello.

PubMed

Janstarkers

2017-08-02

Golden hellos for nurses are okay, but won't improve retention of staff. As soon as new recruits learn how short-staffed wards are and how few trained nurses are on shifts, they won't stay long anyway.

76 FR 52649 - Golden Triangle Storage, Inc.; Notice of Application

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-23

... Triangle Storage, Inc.; Notice of Application On August 5, 2011, Golden Triangle Storage, Inc. (Golden... construct and operate two new salt dome storage caverns at its existing storage site located in Jefferson... Triangle Storage, Inc., 1200 Smith Street, Suite 900, Houston, TX 77002, (832) 397-8642 or John F...

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

PubMed

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

2016-12-15

The present study explores passive avoidance learning and its neural basis in toads (Rhinella arenarum). In Experiment 1, two groups of toads learned to move from a lighted compartment into a dark compartment. After responding, animals in the experimental condition were exposed to an 800-mM strongly hypertonic NaCl solution that leads to weight loss. Control animals received exposure to a 300-mM slightly hypertonic NaCl solution that leads to neither weight gain nor loss. After 10 daily acquisition trials, animals in the experimental group showed significantly longer latency to enter the dark compartment. Additionally, 10 daily trials in which both groups received the 300-mM NaCl solution after responding eliminated this group effect. Thus, experimental animals showed gradual acquisition and extinction of a passive avoidance respond. Experiment 2 replicated the gradual acquisition effect, but, after the last trial, animals were sacrificed and neural activation was assessed in five brain regions using AgNOR staining for nucleoli-an index of brain activity. Higher activation in the experimental animals, relative to controls, was observed in the amygdala and striatum. Group differences in two other regions, lateral pallium and septum, were borderline, but nonsignificant, whereas group differences in the medial pallium were nonsignificant. These preliminary results suggest that a striatal-amygdala activation could be a key component of the brain circuit controlling passive avoidance learning in amphibians. The results are discussed in relation to the results of analogous experiments with other vertebrates. Copyright © 2016 Elsevier B.V. All rights reserved.

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

PubMed

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

2014-01-01

"Brown skin disease" (BSD) is a clinical syndrome of dysecdysis, chronic weight loss and death, previously reported in Puerto Rican crested toads (Peltophryne lemur). Although vitamin A deficiency has been suggested, its cause remains unknown and multiple treatments have failed to prevent or reverse the condition. This study compared the efficacy of vitamin A supplementation, administered in different forms and by different routes, in 48 captive born Puerto Rican crested toads fed from metamorphosis on gut-loaded, dusted, commercially raised crickets. Forty-five toads started to show clinical signs of BSD at 9 months of age; all toads were treated orally with an oil-based vitamin A formulation twice weekly for 2 months but continued to deteriorate. Two treatment groups were then compared: Animals in one group (n=19) received 2 IU injectable vitamin A (Aquasol-A) per gram bodyweight subcutaneously twice weekly for 3 months with no change in diet. Toads in the other group (n=22) received a single oral dose of vitamins A, D3 , and E, and were fed on earthworms and crickets gut-loaded with produce and a finely-ground alfalfa-based pellet, dusted with the same vitamin/mineral supplement. All affected animals developed severe BSD equally and died during, or were euthanized at the end of, the treatment regimen, with no clinical improvement. Animals supplemented with Aquasol-A had significantly higher liver vitamin A concentrations compared with the other treatment group, whereas serum retinol concentrations showed no significant difference. Vitamin A supplementation does not appear a successful treatment once BSD symptoms have developed. © 2014 Wiley Periodicals, Inc.

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

EPA Science Inventory

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

Golden Eagle Monitoring Plan for the Desert Renewable Energy Conservation Plan

USGS Publications Warehouse

Wiens, David; Kolar, Patrick; Katzner, Todd

2018-01-01

This report describes options for monitoring the status and population trends of the golden eagle (Aquila chrysaetos) within the Desert Renewable Energy Conservation Plan (DRECP) area of Southern California in maintaining stable or increasing population in the planning area. The report profiles the ecology of golden eagles in the region and provides a range of potential sampling options to address monitoring needs and objectives. This approach also focused on links between changes in human land-use, golden eagle nesting and foraging habitat conditions, and population dynamics. The report outlines how monitoring data from demographic, prey, and habitat studies were used to develop a predictive demographic model for golden eagles in the DRECP area. Results from the model simulations suggest increases in renewable energy development could have negative consequences for population trajectories. Results also suggest site-specific conservation actions could reduce the magnitude of negative impacts to the local population of eagles. A monitoring framework is proposed including: (1) annual assessments of site-occupancy and reproduction by territorial pairs of golden eagles (including rates at which sites become colonized or vacated over time); (2) estimates of survival, movements, and intensity of use of landscapes by breeding and non-breeding golden eagles; (3) periodic (conducted every two to four years) assessments of nesting and foraging habitats, prey populations, and associations with land-use and management activities; and (4) updating the predictive demographic model with new information obtained on eagles and associated population stressors. The results of this research were published in the Journal of Rapture Research, Wiens, David,Inman, Rich D., Esque, Todd C., Longshore, Kathleen M. and Nussear, Kenneth (2017). Spatial Demographic Models to Inform Conservation Planning of Golden Eagles in Renewable Energy Landscapes. 51(3):234-257.

Mechanisms underlying the organizer formation in Bufo arenarum embryos.

PubMed

Manes, M E; Nieto, O L

1989-06-01

In the early gastrula of Bufo arenarum the prospective mesoderm was previously identified as a marginal belt of grey cells. To analyze their differentiation capacity explants of these cells were cultured within ectodermal vesicles, in isolation and in combination with vegetal components. When cultured in isolation, dorsal and ventral fragments from the deep marginal zone behaved differently. Whilst ventral explants produced blood cells, dorsal explants failed to differentiate, remaining as masses of yolk-laden cells. On the other hand, both cultures were drastically modified when associated with superficial cells from the blastoporal zone, which caused the following effects: a) Promotion of differentiation in dorsal marginal explants, able now to produce notochordal and somitic structures, in addition to mesenchymatic cells. b) Promotion of dorsalization in ventral marginal explants, which changed their expected destiny developing axial components, similar to those furnished by "activated" dorso marginal explants. On the contrary, combined cultures of animal and vegetal pieces were unable to generate mesodermal structures. These studies suggest that the axial mesoderm, identified as the "organizer", develops from a marginal substrate of genuine mesodermal cells through a dorsalizing inductive stimulus originated in superficial periblastoporal cells.

Rod phototransduction determines the trade-off of temporal integration and speed of vision in dark-adapted toads.

PubMed

Haldin, Charlotte; Nymark, Soile; Aho, Ann-Christine; Koskelainen, Ari; Donner, Kristian

2009-05-06

Human vision is approximately 10 times less sensitive than toad vision on a cool night. Here, we investigate (1) how far differences in the capacity for temporal integration underlie such differences in sensitivity and (2) whether the response kinetics of the rod photoreceptors can explain temporal integration at the behavioral level. The toad was studied as a model that allows experimentation at different body temperatures. Sensitivity, integration time, and temporal accuracy of vision were measured psychophysically by recording snapping at worm dummies moving at different velocities. Rod photoresponses were studied by ERG recording across the isolated retina. In both types of experiments, the general timescale of vision was varied by using two temperatures, 15 and 25 degrees C. Behavioral integration times were 4.3 s at 15 degrees C and 0.9 s at 25 degrees C, and rod integration times were 4.2-4.3 s at 15 degrees C and 1.0-1.3 s at 25 degrees C. Maximal behavioral sensitivity was fivefold lower at 25 degrees C than at 15 degrees C, which can be accounted for by inability of the "warm" toads to integrate light over longer times than the rods. However, the long integration time at 15 degrees C, allowing high sensitivity, degraded the accuracy of snapping toward quickly moving worms. We conclude that temporal integration explains a considerable part of all variation in absolute visual sensitivity. The strong correlation between rods and behavior suggests that the integration time of dark-adapted vision is set by rod phototransduction at the input to the visual system. This implies that there is an inexorable trade-off between temporal integration and resolution.

Lethal effect of dehydroleucodine (DhL) on amphibian Bufo arenarum embryos.

PubMed

Moreno, Liliana Elizabeth; Juárez, Américo Osvaldo; Pelzer, Lilian Eugenia

2012-03-01

The dehydroleucodine is a sesquiterpene lactone isolated from Artemisia douglasiana Besser which is used in popular medicine. Toxicity tests using embryos of amphibian have been widely used in order to predict toxic effects of different compounds. However, to our knowledge, there are not studies focussed on the toxic effects of dehydroleucodine on Bufo arenarum, which is an anuran widely distributed in South America. The effect of dehydroleucodine on the survival of embryos was evaluated in an acute test during the early life stage of B. arenarum embryos. Lethality and the degree of adverse effects were dehydroleucodine dose-dependent. Overall, amphibian early life stages appeared to be more susceptible to the embryotoxicity associated with exposure to dehydroleucodine, especially at concentration greater that 3mM. This increased susceptibility may result from the relatively high rate of cellular differentiation and morphogenesis that occurs at this early stage of development. Copyright © 2012 Elsevier Ltd. All rights reserved.

Genetic diversity of Morato's Digger Toad, Proceratophrys moratoi: spatial structure, gene flow, effective size and the need for differential management strategies of populations

PubMed Central

Arruda, Mauricio P.; Costa, William P.; Recco-Pimentel, Shirlei M.

2017-01-01

Abstract The Morato's Digger Toad, Proceratophrys moratoi, is a critically endangered toad species with a marked population decline in southern Brazilian Cerrado. Despite this, new populations are being discovered, primarily in the northern part of the distribution range, which raises a number of questions with regard to the conservation status of the species. The present study analyzed the genetic diversity of the species based on microsatellite markers. Our findings permitted the identification of two distinct management units. We found profound genetic structuring between the southern populations, on the left margin of the Tietê River, and all other populations. A marked reduction was observed in the contemporary gene flow among the central populations that are most affected by anthropogenic impacts, such as extensive sugar cane plantations, which presumably decreases habitat connectivity. The results indicated reduced diversity in the southern populations which, combined with a smaller effective population size, may make these populations more susceptible to extinction. We recommend the reclassification of P. moratoi as vulnerable and the establishment of a special protection program for the southern populations. Our results provide important insights about the local extinction of southern populations of this toad. PMID:28590500

Genetic diversity of Morato's Digger Toad, Proceratophrys moratoi: spatial structure, gene flow, effective size and the need for differential management strategies of populations.

PubMed

Arruda, Mauricio P; Costa, William P; Recco-Pimentel, Shirlei M

2017-01-01

The Morato's Digger Toad, Proceratophrys moratoi, is a critically endangered toad species with a marked population decline in southern Brazilian Cerrado. Despite this, new populations are being discovered, primarily in the northern part of the distribution range, which raises a number of questions with regard to the conservation status of the species. The present study analyzed the genetic diversity of the species based on microsatellite markers. Our findings permitted the identification of two distinct management units. We found profound genetic structuring between the southern populations, on the left margin of the Tietê River, and all other populations. A marked reduction was observed in the contemporary gene flow among the central populations that are most affected by anthropogenic impacts, such as extensive sugar cane plantations, which presumably decreases habitat connectivity. The results indicated reduced diversity in the southern populations which, combined with a smaller effective population size, may make these populations more susceptible to extinction. We recommend the reclassification of P. moratoi as vulnerable and the establishment of a special protection program for the southern populations. Our results provide important insights about the local extinction of southern populations of this toad.

Golden Ratio and the heart: A review of divine aesthetics.

PubMed

Yalta, Kenan; Ozturk, Selcuk; Yetkin, Ertan

2016-07-01

In human history, certain mathematical figures or concepts had gained a significant reputation largely due to their occult and esoteric meanings. Among these, Golden Ratio and associated concepts, namely golden proportions, had elicited a tremendous breakthrough in our human awareness and perception regarding mundane and spiritual aspects of physical existence. Golden Ratio or Number (with a numerical value of 1.618) that is also referred to as the Greek letter Phi (φ), has been universally expressed on a line partitioned into two unequal lengths (L, the longer and S, the shorter) in such a manner that L/S=(L+S)/L. Besides, appearing in certain number sequences (Fibonacci Series, etc.), golden proportions, to the consternation of observers, appear to be strikingly prevalent across all levels of physical existence from the innermost structures to the colossal galaxies of the universe potentially labeling these concepts as the measures of divine aesthetics. Accordingly, the human body also serves as an epitome of these mysterious concepts as exemplified by its outward appearance including general stature and extremities along with a variety of inner organ systems. Based on preliminary studies, the human cardiovascular system might also be suggested to serve as a major predilection site of divine aesthetics as measured with Golden Ratio and its allies. This appears to be completely in line with the ancient knowledge associating the human heart with the esoteric and spiritual components of human nature including human soul. Within this context, the present paper primarily aims to discuss human manifestations of divine aesthetics as measured with 'Golden Ratio' and associated indices with a particular and detailed emphasis on their potential link with the human cardiovascular system. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Influence of demography and environment on persistence in toad populations

USGS Publications Warehouse

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

2016-01-01

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

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

Treesearch

Cathryn H. Greenberg; George W. Tanner

2004-01-01

Eastern Spadefoot Toads (Scaphiopus holbrookii) require fish-free, isolated, ephemeral ponds for breeding but otherwise inhabit surrounding uplands, commonly xeric longleaf pine (Pinus palustris) and wiregrass (Aristida beyrichiana) ecosystem. Fire suppression in the Florida sandhills has the potential to alter...

Mobius Assembly: A versatile Golden-Gate framework towards universal DNA assembly

PubMed Central

Andreou, Andreas I.

2018-01-01

Synthetic biology builds upon the foundation of engineering principles, prompting innovation and improvement in biotechnology via a design-build-test-learn cycle. A community-wide standard in DNA assembly would enable bio-molecular engineering at the levels of predictivity and universality in design and construction that are comparable to other engineering fields. Golden Gate Assembly technology, with its robust capability to unidirectionally assemble numerous DNA fragments in a one-tube reaction, has the potential to deliver a universal standard framework for DNA assembly. While current Golden Gate Assembly frameworks (e.g. MoClo and Golden Braid) render either high cloning capacity or vector toolkit simplicity, the technology can be made more versatile—simple, streamlined, and cost/labor-efficient, without compromising capacity. Here we report the development of a new Golden Gate Assembly framework named Mobius Assembly, which combines vector toolkit simplicity with high cloning capacity. It is based on a two-level, hierarchical approach and utilizes a low-frequency cutter to reduce domestication requirements. Mobius Assembly embraces the standard overhang designs designated by MoClo, Golden Braid, and Phytobricks and is largely compatible with already available Golden Gate part libraries. In addition, dropout cassettes encoding chromogenic proteins were implemented for cost-free visible cloning screening that color-code different cloning levels. As proofs of concept, we have successfully assembled up to 16 transcriptional units of various pigmentation genes in both operon and multigene arrangements. Taken together, Mobius Assembly delivers enhanced versatility and efficiency in DNA assembly, facilitating improved standardization and automation. PMID:29293531

Mobius Assembly: A versatile Golden-Gate framework towards universal DNA assembly.

PubMed

Andreou, Andreas I; Nakayama, Naomi

2018-01-01

Synthetic biology builds upon the foundation of engineering principles, prompting innovation and improvement in biotechnology via a design-build-test-learn cycle. A community-wide standard in DNA assembly would enable bio-molecular engineering at the levels of predictivity and universality in design and construction that are comparable to other engineering fields. Golden Gate Assembly technology, with its robust capability to unidirectionally assemble numerous DNA fragments in a one-tube reaction, has the potential to deliver a universal standard framework for DNA assembly. While current Golden Gate Assembly frameworks (e.g. MoClo and Golden Braid) render either high cloning capacity or vector toolkit simplicity, the technology can be made more versatile-simple, streamlined, and cost/labor-efficient, without compromising capacity. Here we report the development of a new Golden Gate Assembly framework named Mobius Assembly, which combines vector toolkit simplicity with high cloning capacity. It is based on a two-level, hierarchical approach and utilizes a low-frequency cutter to reduce domestication requirements. Mobius Assembly embraces the standard overhang designs designated by MoClo, Golden Braid, and Phytobricks and is largely compatible with already available Golden Gate part libraries. In addition, dropout cassettes encoding chromogenic proteins were implemented for cost-free visible cloning screening that color-code different cloning levels. As proofs of concept, we have successfully assembled up to 16 transcriptional units of various pigmentation genes in both operon and multigene arrangements. Taken together, Mobius Assembly delivers enhanced versatility and efficiency in DNA assembly, facilitating improved standardization and automation.

Wintering Golden Eagles on the coastal plain of South Carolina

Treesearch

Mark Vukovich; K.L. Turner; T.E. Grazia; T. Mims; J.C. Beasley; John Kilgo

2015-01-01

Golden Eagles (Aquila chrysaetos) are rare winter residents in eastern North America, with most found along the Appalachian Mountains and few reported on the coastal plain of the Carolinas. We used remote cameras baited with wild pig (Sus scrofa) and white-tailed deer (Odocoileus virginianus) carcasses to detect, age, and individually identify Golden Eagles on the U.S...

Is University Education a Golden Key for a Happy Life?

ERIC Educational Resources Information Center

Lee, Jeong-Kyu

2008-01-01

This article explores what the ultimate purpose of university education is, and whether a university is indeed a golden key for a happy life. Two research questions are addressed as follows: for what the young study in a university?; and a university, is it a golden key for happiness? To defend the research questions systematically, the author…

The golden-mean surface pattern to enhance flow mixing in micro-channel.

PubMed

Wang, J F; Liu, Y; Xu, Y S

2009-04-01

Mixing of analytes and reagents in microfluidic devices is often crucial to the effective functioning of lab-on-a-chip. It is possible to affect the mixing in microfluidics by intelligently controlling the thermodynamic and chemical properties of the substrate surface. Numerous studies have shown that the phase behavior of mixtures is significantly affected by surface properties of microfluidics. For example, the phase separation between the fluids can be affected by heterogeneous patterns on the substrate. The patterned substrate can offer an effective means to control fluid behavior and in turn to enhance mixing. The golden mean is a ratio that is present in the growth patterns of many biological systems--the spiral formed by a shell or the curve of a fern, for example. The golden mean or golden section was derived by the ancient Greeks. Like "pi" the golden mean ratio is an irrational number 1.618, or (square root{5} + 1) / 2. It was found that the golden mean was an optimum ratio in natural convection heat transfer problem (Liu and Phan-Thien, Numer Heat Transf 37:613-630, 2000). In this study, we numerically studied the effect of optimum surface pattern on mixing in a micro channel and found that the flow oscillation and chaotic mixing were enhanced apparently when the ratio of hydrophobic and hydrophilic boundary follows the golden mean.

Wintering Golden Eagles on the coastal plain of South Carolina

DOE PAGES

Vukovich, Mark; Turner, Kelsey L.; Grazia, Tracy E.; ...

2015-10-01

Golden Eagles (Aquila chrysaetos) are rare winter residents in eastern North America, with most found along the Appalachian Mountains and few reported on the coastal plain of the Carolinas. We used remote cameras baited with wild pig (Sus scrofa) and white-tailed deer (Odocoileus virginianus) carcasses to detect, age, and individually identify Golden Eagles on the U.S. Department of Energy’s Savannah River Site on the coastal plain of South Carolina. We identified eight individual Golden Eagles during the winters of 2013–2014 and 2014–2015, with one detected during both winters. We detected eagles for 19 and 66 calendar days during the wintersmore » of 2013–2014 and 2014–2015, respectively, with two adult eagles detected for 30 and 31 calendar days in 2014–2015. Eagles typically scavenged on carcasses for a few days, left, and then returned when cameras were baited with another carcass, suggesting they had remained in the area. These observations suggest that large tracts of forests on the coastal plain may be important wintering areas for some Golden Eagles and, further, that other areas in the coastal plain of the southeastern United States may also harbor wintering eagles. Identification of wintering areas of Golden Eagles in the east will be an important step in the conservation of this protected species, and camera traps baited with carcasses can be an effective tool for such work.« less

Wintering Golden Eagles on the coastal plain of South Carolina

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vukovich, Mark; Turner, Kelsey L.; Grazia, Tracy E.

Golden Eagles (Aquila chrysaetos) are rare winter residents in eastern North America, with most found along the Appalachian Mountains and few reported on the coastal plain of the Carolinas. We used remote cameras baited with wild pig (Sus scrofa) and white-tailed deer (Odocoileus virginianus) carcasses to detect, age, and individually identify Golden Eagles on the U.S. Department of Energy’s Savannah River Site on the coastal plain of South Carolina. We identified eight individual Golden Eagles during the winters of 2013–2014 and 2014–2015, with one detected during both winters. We detected eagles for 19 and 66 calendar days during the wintersmore » of 2013–2014 and 2014–2015, respectively, with two adult eagles detected for 30 and 31 calendar days in 2014–2015. Eagles typically scavenged on carcasses for a few days, left, and then returned when cameras were baited with another carcass, suggesting they had remained in the area. These observations suggest that large tracts of forests on the coastal plain may be important wintering areas for some Golden Eagles and, further, that other areas in the coastal plain of the southeastern United States may also harbor wintering eagles. Identification of wintering areas of Golden Eagles in the east will be an important step in the conservation of this protected species, and camera traps baited with carcasses can be an effective tool for such work.« less

Reproductive characteristics of migratory golden eagles in Denali National Park, Alaska

USGS Publications Warehouse

McIntyre, Carol L.; Adams, Layne G.

1999-01-01

We describe reproductive characteristics of Golden Eagles (Aquila chrysaetos) breeding in Denali National Park, Alaska during an entire snowshoe hare (Lepus americanus) cycle, 1988-1997. Data on nesting eagles were collected at 58 to 72 nesting areas annually using two aerial surveys. Surveys were conducted during the incubation period to determine occupancy and nesting activities and late in the nestling period to count nestlings and determine nesting success. Annual occupancy rates of nesting areas did not vary significantly, whereas laying rates, success rates, and mean brood size varied significantly over the study period. Fledgling production for the study population varied sevenfold during the ten-year period. Laying rates, mean brood size, and overall population productivity were significantly correlated with abundance of cyclic snowshoe hare and Willow Ptarmigan (Lugopus lagopus) populations. Reproductive rates of Golden Eagles in Denali were similar to those of Golden Eagles from other high latitude study areas in North America, but lower than for Golden Eagles from temperate zone study areas in North America.

Improving the nutritional value of Golden Rice through increased pro-vitamin A content.

PubMed

Paine, Jacqueline A; Shipton, Catherine A; Chaggar, Sunandha; Howells, Rhian M; Kennedy, Mike J; Vernon, Gareth; Wright, Susan Y; Hinchliffe, Edward; Adams, Jessica L; Silverstone, Aron L; Drake, Rachel

2005-04-01

"Golden Rice" is a variety of rice engineered to produce beta-carotene (pro-vitamin A) to help combat vitamin A deficiency, and it has been predicted that its contribution to alleviating vitamin A deficiency would be substantially improved through even higher beta-carotene content. We hypothesized that the daffodil gene encoding phytoene synthase (psy), one of the two genes used to develop Golden Rice, was the limiting step in beta-carotene accumulation. Through systematic testing of other plant psys, we identified a psy from maize that substantially increased carotenoid accumulation in a model plant system. We went on to develop "Golden Rice 2" introducing this psy in combination with the Erwinia uredovora carotene desaturase (crtI) used to generate the original Golden Rice. We observed an increase in total carotenoids of up to 23-fold (maximum 37 microg/g) compared to the original Golden Rice and a preferential accumulation of beta-carotene.

Golden eagle population trends in the western United States: 1968-2010

USGS Publications Warehouse

Millsap, Brian A.; Zimmerman, Guthrie S.; Sauer, John R.; Nielson, Ryan M.; Otto, Mark; Bjerre, Emily; Murphy, Robert K.

2013-01-01

In 2009, the United States Fish and Wildlife Service promulgated permit regulations for the unintentional lethal take (anthropogenic mortality) and disturbance of golden eagles (Aquila chrysaetos). Accurate population trend and size information for golden eagles are needed so agency biologists can make informed decisions when eagle take permits are requested. To address this need with available data, we used a log-linear hierarchical model to average data from a late-summer aerial-line-transect distance-sampling survey (WGES) of golden eagles in the United States portions of Bird Conservation Region (BCR) 9 (Great Basin), BCR 10 (Northern Rockies), BCR 16 (Southern Rockies/Colorado Plateau), and BCR 17 (Badlands and Prairies) from 2006 to 2010 with late-spring, early summer Breeding Bird Survey (BBS) data for the same BCRs and years to estimate summer golden eagle population size and trends in these BCRs. We used the ratio of the density estimates from the WGES to the BBS index to calculate a BCR-specific adjustment factor that scaled the BBS index (i.e., birds per route) to a density estimate. Our results indicated golden eagle populations were generally stable from 2006 to 2010 in the 4 BCRs, with an estimated average rate of population change of −0.41% (95% credible interval [CI]: −4.17% to 3.40%) per year. For the 4 BCRs and years, we estimated annual golden eagle population size to range from 28,220 (95% CI: 23,250–35,110) in 2007 to 26,490 (95% CI: 21,760–32,680) in 2008. We found a general correspondence in trends between WGES and BBS data for these 4 BCRs, which suggested BBS data were providing useful trend information. We used the overall adjustment factor calculated from the 4 BCRs and years to scale BBS golden eagle counts from 1968 to 2005 for the 4 BCRs and for 1968 to 2010 for the 8 other BCRs (without WGES data) to estimate golden eagle population size and trends across the western United States for the period 1968 to 2010. In general, we

Evaluation of maxillary anterior teeth and their relation to the golden proportion in Malaysian population.

PubMed

Al-Marzok, Maan Ibrahim; Majeed, Kais Raad Abdul; Ibrahim, Ibrahim Khalil

2013-01-24

The maxillary anterior teeth are important in achieving pleasing dental aesthetics. Various methods are used to measure the size and form of them, including the golden proportion between their perceived widths, and the width-to-height ratio, referred to as the golden standard. The purpose of this study was conducted to evaluate whether consistent relationships exist between tooth width and height of the clinical crown dimensions; and to investigate the occurrence of the golden proportion of the maxillary anterior teeth. Dental casts of the maxillary arches were made in this cross-sectional study from MAHSA University College students who met the inclusion criteria. The 49 participants represented the Malaysian population main ethnics. The dimensions of the anterior teeth and the perceived width of anterior teeth viewed from front were measured using a digital caliper. Comparison of the perceived width ratio of lateral to central incisor and canine to lateral incisor with the golden proportion of 0.618 revealed there were a significant statistical difference (p < 0.05). The statistical difference was significant for the width-to-height ratio of central incisors to the golden standard of 80%. There was no significant difference in the comparison among ethnic groups for the golden proportion and the golden standard. The golden proportion was not found to exist between the perceived widths of maxillary anterior teeth. No golden standard were detected for the width-to-height proportions of maxillary incisors. Specific population characteristics and perception of beauty must be considered. However, ethnicity has no association with the proportions of maxillary anterior teeth.

Voyager Special Cargo: The Golden Record

NASA Image and Video Library

2011-04-29

This image highlights the special cargo onboard NASA Voyager spacecraft: the Golden Record. Each of the two Voyager spacecraft launched in 1977 carry a 12-inch gold-plated phonograph record with images and sounds from Earth.

THE ANATOMIC SITE OF THE TRANSEPITHELIAL PERMEABILITY BARRIERS OF TOAD BLADDER

PubMed Central

DiBona, Donald R.; Civan, Mortimer M.; Leaf, Alexander

1969-01-01

An examination of the mucosal epithelium of the urinary bladder of the toad reveals that the two major cell types which abut on the urinary surface, the granular and mitochondria-rich cells, also contact the basement membrane. Thus, the epithelium functions as a single cell layer. Although basal cells are interpolated between the granular cells and the basement membrane over a large portion of the epithelium, they do not constitute an additional continuous cell layer. This finding is consistent with extensive physiological data which had assumed that the major permeability barriers of this epithelium were the apical and basal-lateral plasma membranes of a single layer of cells. PMID:5782445

The impact of concomitant infections by Trypanosoma cruzi and intestinal helminths on the health of wild golden and golden-headed lion tamarins.

PubMed

Monteiro, Rafael V; Dietz, James M; Jansen, Ana Maria

2010-08-01

A 4-year longitudinal epidemiological study was carried out to evaluate the effect of infection by Trypanosoma cruzi and three intestinal helminth species on the health of golden and golden-headed lion tamarins. We evaluated health using analysis of blood counts, serum proteins, electrophoretograms, electrocardiograms and a health ranking based on physiological parameters. Among the helminths, Trichostrongylidae was demonstrated as the most pathogenic, followed by Prosthenorchis sp.; concomitant infection by Spiruridae may exacerbate the negative effects of the other two helminths. T. cruzi infection was not highly detrimental to the health of the study animals and was correlated with increased resilience to helminths. Tamarins younger than 1-year of age or older than 4-years had lower health condition. Golden-headed lion tamarins were in lower health condition because of higher parasitic prevalence. Our data suggest that when parasite community pathogenicity and prevalence are high, natural selection will allow survival only of lion tamarins in the best health condition. Copyright 2010. Published by Elsevier India Pvt Ltd.

Visibility in a pure model of golden spiral phyllotaxis.

PubMed

Herrmann, Burghard

2018-07-01

This paper considers the geometry of plants with golden spiral phyllotaxis, i.e. growing leaf by leaf on a spiral with golden divergence angle, via the simplest mathematical model, a cylinder with regular arrangement of points on its surface. As is well-known, Fibonacci numbers appear by means of the order of parastichies. This fact is shown to be a straightforward application of logical consequences to a particular model with respect to pure visibility. This notion is very similar to that of contact parastichies. The 3-D cylindrical model of golden spiral phyllotaxis abstracts from the form of leaves and identifies them with points. Pure visibility is specified in the 2-D representation so that common sense parastichies can be scrutinized. The main Theorem states that the orders of the purely most visible parastichies are Fibonacci numbers. Copyright © 2018 Elsevier Inc. All rights reserved.

Effects of metal and predator stressors in larval southern toads (Anaxyrus terrestris).

PubMed

Rumrill, Caitlin T; Scott, David E; Lance, Stacey L

2016-08-01

Natural and anthropogenic stressors typically do not occur in isolation; therefore, understanding ecological risk of contaminant exposure should account for potential interactions of multiple stressors. Realistically, common contaminants can also occur chronically in the environment. Because parental exposure to stressors may cause transgenerational effects on offspring, affecting their ability to cope with the same or novel environmental stressors, the exposure histories of generations preceding that being tested should be considered. To examine multiple stressor and parental exposure effects we employed a 2 × 2 × 2 factorial design in outdoor 1000-L mesocosms (n = 24). Larval southern toads (Anaxyrus terrestris), bred from parents collected from reference and metal-contaminated sites, were exposed to two levels of both an anthropogenic (copper-0, 30 µg/L Cu) and natural (predator cue - present/absent) stressor and reared to metamorphosis. Toads from the metal-contaminated parental source population were smaller at metamorphosis and had delayed development; i.e., a prolonged larval period. Similarly, larval Cu exposure also reduced size at metamorphosis and prolonged the larval period. We, additionally, observed a significant interaction between larval Cu and predator-cue exposure on larval period, wherein delayed emergence was only present in the 30-µg/L Cu treatments in the absence of predator cues. The presence of parental effects as well as an interaction between aquatic stressors on commonly measured endpoints highlight the importance of conducting multistressor studies across generations to obtain data that are more relevant to field conditions in order to determine population-level effects of contaminant exposure.

76 FR 56220 - Draft Environmental Impact Statement for General Management Plan for Golden Gate National...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-12

... Environmental Impact Statement for General Management Plan for Golden Gate National Recreation Area and Muir... Management Plan for Golden Gate National Recreation Area and Muir Woods National Monument. SUMMARY: In accord... Environmental Impact Statement (Draft EIS) for the updating the General Management Plan (GMP) for Golden Gate...

When frequencies never synchronize: the golden mean and the resting EEG.

PubMed

Pletzer, Belinda; Kerschbaum, Hubert; Klimesch, Wolfgang

2010-06-04

The classical frequency bands of the EEG can be described as a geometric series with a ratio (between neighbouring frequencies) of 1.618, which is the golden mean. Here we show that a synchronization of the excitatory phases of two oscillations with frequencies f1 and f2 is impossible (in a mathematical sense) when their ratio equals the golden mean, because their excitatory phases never meet. Thus, in a mathematical sense, the golden mean provides a totally uncoupled ('desynchronized') processing state which most likely reflects a 'resting' brain, which is not involved in selective information processing. However, excitatory phases of the f1- and f2-oscillations occasionally come close enough to coincide in a physiological sense. These coincidences are more frequent, the higher the frequencies f1 and f2. We demonstrate that the pattern of excitatory phase meetings provided by the golden mean as the 'most irrational' number is least frequent and most irregular. Thus, in a physiological sense, the golden mean provides (i) the highest physiologically possible desynchronized state in the resting brain, (ii) the possibility for spontaneous and most irregular (!) coupling and uncoupling between rhythms and (iii) the opportunity for a transition from resting state to activity. These characteristics have already been discussed to lay the ground for a healthy interplay between various physiological processes (Buchmann, 2002). Copyright 2010 Elsevier B.V. All rights reserved.

Analysis of the respiratory component of heart rate variability in the Cururu toad Rhinella schneideri.

PubMed

Zena, Lucas A; Leite, Cléo A C; Longhini, Leonardo S; Dias, Daniel P M; da Silva, Glauber S F; Hartzler, Lynn K; Gargaglioni, Luciane H; Bícego, Kênia C

2017-11-23

Beat-to-beat variation in heart rate (f H ) has been used as a tool for elucidating the balance between sympathetic and parasympathetic modulation of the heart. A portion of the temporal changes in f H is evidenced by a respiratory influence (cardiorespiratory interaction) on heart rate variability (HRV) with heartbeats increasing and decreasing within a respiratory cycle. Nevertheless, little is known about respiratory effects on HRV in lower vertebrates. By using frequency domain analysis, we provide the first evidence of a ventilatory component in HRV similar to mammalian respiratory sinus arrhythmia in an amphibian, the toad Rhinella schneideri. Increases in the heartbeats arose synchronously with each lung inflation cycle, an intermittent breathing pattern comprised of a series of successive lung inflations. A well-marked peak in the HRV signal matching lung inflation cycle was verified in toads whenever lung inflation cycles exhibit a regular rhythm. The cardiac beat-to-beat variation evoked at the moment of lung inflation accounts for both vagal and sympathetic influences. This cardiorespiratory interaction may arise from interactions between central and peripheral feedback mechanisms governing cardiorespiratory control and may underlie important cardiorespiratory adjustments for gas exchange improvement especially under extreme conditions like low oxygen availability.

Duration of extinction trials as a determinant of instrumental extinction in terrestrial toads (Rhinella arenarum).

PubMed

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

2018-01-01

Instrumental learning guides behavior toward resources. When such resources are no longer available, approach to previously reinforced locations is reduced, a process called extinction. The present experiments are concerned with factors affecting the extinction of acquired behaviors in toads. In previous experiments, total reward magnitude in acquisition and duration of extinction trials were confounded. The present experiments were designed to test the effects of these factors in factorial designs. Experiment 1 varied reward magnitude (900, 300, or 100 s of water access per trial) and amount of acquisition training (5 or 15 daily trials). With total amount of water access equated in acquisition, extinction with large rewards was faster (longer latencies in 900/5 than 300/15), but with total amount of training equated, extinction with small rewards was faster (longer latencies in 100/15 than 300/15). Experiment 2 varied reward magnitude (1200 or 120 s of water access per trial) while holding constant the number of acquisition trials (5 daily trials) and the duration of extinction trials (300 s). Extinction performance was lower with small, rather than large reward magnitude (longer latencies in 120/300 than in 1200/300). Thus, instrumental extinction depends upon the amount of time toads are exposed to the empty goal compartment during extinction trials.

Characterization of Bufo arenarum oocyte plasma membrane proteins that interact with sperm.

PubMed

Coux, Gabriela; Cabada, Marcelo O

2006-04-28

Sperm-oocyte plasma membrane interaction is an essential step in fertilization. In amphibians, the molecules involved have not been identified. Our aim was to detect and characterize oocyte molecules with binding affinity for sperm. We isolated plasma membranes free from vitelline envelope and yolk proteins from surface-biotinylated Bufo arenarum oocytes. Using binding assays we detected a biotinylated 100 kDa plasma membrane protein that consistently bound to sperm. Chromatographic studies confirmed the 100 kDa protein and detected two additional oocyte molecules of 30 and 70 kDa with affinity for sperm. Competition studies with an integrin-interacting peptide and cross-reaction with an anti-HSP70 antibody suggested that the 100 and 70 kDa proteins are members of the integrin family and HSP70, respectively. MS/MS analysis suggested extra candidates for a role in this step of fertilization. In conclusion, we provide evidence for the involvement of several proteins, including integrins and HSP70, in B. arenarum sperm-oocyte plasma membrane interactions.

Differential sensitivity to the antifouling chemical medetomidine between wood frog and American toad tadpoles with evidence for low-dose stimulation and high-dose inhibition of metamorphosis.

PubMed

Fong, Peter P; Lambert, Olivia J; Hoagland, Margot L; Kurtz, Emily R

2018-05-05

Antifouling chemicals are legacy contaminants in aquatic ecosystems. Previous experiments have shown that a 14-day exposure to the antifouling chemical medetomidine delays metamorphosis and reduces body mass in wood frog tadpoles. In the present study, we exposed wood frog tadpoles to medetomidine for 3, 7, and 10 days at 100 nM, 1 μM, and 10 μM. We also exposed American toad tadpoles to medetomidine for 3 days at four concentrations (10 nM, 100 nM, 1 μM, and 10 μM) in static renewal experiments. In each experiment, we measured growth, frequency and time to metamorphosis, and mass at metamorphosis. In both species, medetomidine significantly slowed development as measured by the Gosner stage. After 34 days in culture, wood frog tadpoles exposed to 1 and 10 μM medetomidine for as few as 3 days were significantly less developed compared to controls. Toads exposed to 1 μM medetomidine for 3 days were also significantly less developed on day 27, but by day 34, there was no difference from controls. For wood frogs, medetomidine significantly affected time to metamorphosis with a trend for tadpoles at lower concentrations metamorphosing sooner than those at higher concentrations. While medetomidine affected time to metamorphosis in wood frogs, it did not affect fresh mass, dry mass, or mortality compared to controls. Wood frog tadpoles that did not metamorphose after over 90 days in culture were more frequent in high-concentration groups than in the control. In toads, 10 μM medetomidine was 100% lethal within 23 days, but at the same concentration and duration, no wood frog tadpoles died. Lower concentrations were also significantly lethal to toads compared to controls, but tadpoles that survived in 10 and 100 nM metamorphosed sooner than those in 1 μM. Fresh mass of toad tadpoles exposed to 1 μm was significantly smaller at metamorphosis compared to that of controls. Medetomidine also affected the behavior of tadpoles. In toads, medetomidine

Joint estimation of habitat dynamics and species interactions: Disturbance reduces co-occurrence of non-native predators with an endangered toad

USGS Publications Warehouse

Miller, David A.W.; Brehme, Cheryl S.; Hines, James E.; Nichols, James D.; Fisher, Robert N.

2012-01-01

1. Ecologists have long been interested in the processes that determine patterns of species occurrence and co-occurrence. Potential short-comings of many existing empirical approaches that address these questions include a reliance on patterns of occurrence at a single time point, failure to account properly for imperfect detection and treating the environment as a static variable.2. We fit detection and non-detection data collected from repeat visits using a dynamic site occupancy model that simultaneously accounts for the temporal dynamics of a focal prey species, its predators and its habitat. Our objective was to determine how disturbance and species interactions affect the co-occurrence probabilities of an endangered toad and recently introduced non-native predators in stream breeding habitats. For this, we determined statistical support for alternative processes that could affect co-occurrence frequency in the system.3. We collected occurrence data at stream segments in two watersheds where streams were largely ephemeral and one watershed dominated by perennial streams. Co-occurrence probabilities of toads with non-native predators were related to disturbance frequency, with low co-occurrence in the ephemeral watershed and high co-occurrence in the perennial watershed. This occurred because once predators were established at a site, they were rarely lost from the site except in cases when the site dried out. Once dry sites became suitable again, toads colonized them much more rapidly than predators, creating a period of predator-free space.4. We attribute the dynamics to a storage effect, where toads persisting outside the stream environment during periods of drought rapidly colonized sites when they become suitable again. Our results support that even in highly connected stream networks, temporal disturbance can structure frequencies with which breeding amphibians encounter non-native predators.5. Dynamic multi-state occupancy models are a powerful

Joint estimation of habitat dynamics and species interactions: disturbance reduces co-occurrence of non-native predators with an endangered toad.

PubMed

Miller, David A W; Brehme, Cheryl S; Hines, James E; Nichols, James D; Fisher, Robert N

2012-11-01

1. Ecologists have long been interested in the processes that determine patterns of species occurrence and co-occurrence. Potential short-comings of many existing empirical approaches that address these questions include a reliance on patterns of occurrence at a single time point, failure to account properly for imperfect detection and treating the environment as a static variable. 2. We fit detection and non-detection data collected from repeat visits using a dynamic site occupancy model that simultaneously accounts for the temporal dynamics of a focal prey species, its predators and its habitat. Our objective was to determine how disturbance and species interactions affect the co-occurrence probabilities of an endangered toad and recently introduced non-native predators in stream breeding habitats. For this, we determined statistical support for alternative processes that could affect co-occurrence frequency in the system. 3. We collected occurrence data at stream segments in two watersheds where streams were largely ephemeral and one watershed dominated by perennial streams. Co-occurrence probabilities of toads with non-native predators were related to disturbance frequency, with low co-occurrence in the ephemeral watershed and high co-occurrence in the perennial watershed. This occurred because once predators were established at a site, they were rarely lost from the site except in cases when the site dried out. Once dry sites became suitable again, toads colonized them much more rapidly than predators, creating a period of predator-free space. 4. We attribute the dynamics to a storage effect, where toads persisting outside the stream environment during periods of drought rapidly colonized sites when they become suitable again. Our results support that even in highly connected stream networks, temporal disturbance can structure frequencies with which breeding amphibians encounter non-native predators. 5. Dynamic multi-state occupancy models are a powerful tool

China Confronts Afghan Drugs: Law Enforcement Views of The Golden Crescent

DTIC Science & Technology

2011-03-01

US-China relations, and insights into critical developments within China itself. Whether focused on Chinese defense and security issues, Beijing’s... Chinese Assessments of Smuggling and Trafficking Golden Crescent Drugs into Western China.........................................................6... Chinese Assessments of the Growing Seriousness of Golden Crescent Drug Trafficking in Relation to China’s Overall Illegal Drug Patterns

Spatial and structural interrelationships between secretory cells of the subcommissural organ and blood vessels. An immunocytochemical study.

PubMed

Rodríguez, E M; Oksche, A; Hein, S; Rodríguez, S; Yulis, R

1984-01-01

In 76 specimens (amphibians, reptilians, mammals) belonging to 25 different vertebrate species, the region of the subcommissural organ (SCO) was investigated with the use of a primary antiserum raised against an extract of bovine Reissner's fiber + the immunoperoxidase procedure according to Sternberger et al. (1970). In the SCO of a toad (Bufo arenarum) and several species of reptiles (lacertilians, ophidians, crocodilians), the ependymal cells were the only type of secretory cell displaying vascular contacts, whereas in mammals ependymal and hypendymal cells established intimate spatial contacts with blood vessels. In Bufo arenarum, but especially in the reptilian species examined, the ependymo-vascular relationship was exerted by a population of ependymal cells having a rather constant location within the SCO and projecting to capillaries that showed a remarkably constant pattern of anatomical distribution. In the SCO of mammals the modality and degree of the structural relationships between secretory cells and blood vessels varied greatly from species to species. In the SCO of the armadillo and dog the secretory tissue was organized as a thick, highly vascularized layer with most of the cells oriented toward the capillaries. A rather opposite situation was found in the SCO of New- and Old-World monkeys, where vascular contacts were restricted to a few ependymal cells.

An ATP-gated cation channel with some P2Z-like characteristics in gastric smooth muscle cells of toad.

PubMed Central

Ugur, M; Drummond, R M; Zou, H; Sheng, P; Singer, J J; Walsh, J V

1997-01-01

1. Whole-cell and single-channel currents elicited by extracellular ATP were studied in freshly dissociated smooth muscle cells from the stomach of the toad Bufo marinus using standard patch clamp and microfluorimetric techniques. 2. This ATP-gated cation channel shares a number of pharmacological and functional properties with native rat myometrium receptors, certain native P2Z purinoceptors and the recently cloned P2X7 purinoceptor. But, unlike the last two, the ATP-gated channel does not mediate the formation of large non-specific pores. Thus, it may represent a novel member of the P2X or P2Z class. 3. Extracellular application of ATP (> or = 150 microM) elicited an inward whole-cell current at negative holding potentials that was inwardly rectifying and showed no sign of desensitization. Na+, Cs+ and, to a lesser degree, the organic cation choline served as charge carriers, but Cl- did not. Ratiometric fura-2 measurements indicated that the current is carried in part by Ca2+. The EC50 for ATP was 700 microM in solutions with a low divalent cation concentration. 4. ATP (> or = 100 microM) at the extracellular surface of cell-attached or excised patches elicited inwardly rectifying single-channel currents with a 22 pS conductance. Cl- did not serve as a charge carrier but both Na+ and Cs+ did, as did choline to a lesser extent. The mean open time of the channel was quite long, with a range in hundreds of milliseconds at a holding potential of -70 mV. 5. Mg2+ and Ca2+ decreased the magnitude of the ATP-induced whole-cell currents. Mg2+ decreased both the amplitude and the activity of ATP-activated single-channel currents. 6. ADP, UTP, P1, P5-di-adenosine pentaphosphate (AP5A), adenosine and alpha, beta-methylene ATP (alpha, beta-Me-ATP) did not induce significant whole-cell current. ATP-gamma-S and 2-methylthio ATP (2-Me-S-ATP) were significantly less effective than ATP in inducing whole-cell currents, whereas benzoylbenzoyl ATP (BzATP) was more effective. Bz

Lead and mercury in fall migrant golden eagles from western North America.

PubMed

Langner, Heiko W; Domenech, Robert; Slabe, Vincent A; Sullivan, Sean P

2015-07-01

Lead exposure from ingestion of bullet fragments is a serious environmental hazard to eagles. We determined blood lead levels (BLL) in 178 golden eagles (Aquila chrysaetos) captured during fall migration along a major North American flyway. These eagles spent the breeding season distributed over a large range and are the best currently available representation of free flying golden eagles on the continent. We found 58 % of these eagles containing increased BLL > 0.1 mg/L; 10 % were clinically lead poisoned with BLL > 0.6 mg/L; and 4 % were lethally exposed with BLL > 1.2 mg/L. No statistical difference in BLL existed between golden and bald eagles (Haliaeetus leucocephalus). Golden eagles captured on carrion had higher BLL than those captured using live bait suggesting differences in feeding habits among individuals. Median BLL increased with age class. We propose a conceptual model for the long-term increase in BLL after ingestion of lead particles. The mean blood mercury level in golden eagles was 0.023 mg/L. We evaluate a field test for BLL that is based on anodic stripping voltammetry. This cost-effective and immediate method correlated well with results from inductively coupled plasma-mass spectrometry, although results needed to be corrected for each calibration of the test kit.

Application of Focused Ultrasound-Assisted Extraction for the Quantification of Persistent Organic Pollutions in Liver Tissue of Giant Toad (Rhinella marina).

PubMed

Flores-Ramírez, R; Espinosa-Reyes, G; Cilia-López, V G; González-Mille, D J; Rodríguez-Aguilar, M; Díaz de León-Martínez, L; Díaz-Barriga, F

2017-02-01

A simple and rapid focused ultrasound extraction method was developed for the determination of Persistent Organic Pollutants (POPs) in liver tissue obtained of giant toad (Rhinella marina) using a gas chromatography coupled to a mass detector with electron impact ionization. The performed method for POPs, was validated in fortified matrix, showing linearity from the LOQ up to 100 ng/mL; LODs and LOQs for each compound were between 1.7 and 4.8 and 3.5-7.5 ng/mL, respectively. Recovery rates were among 79%-116% for POPs determined. Finally, the method was applied in liver samples of giant toads found in a malarial area in Mexico. The sensitivity of the proposed method was good enough to ensure reliable determination of target analytes at concentration levels commonly found in this kind of samples.

Golden Gait: An Optimization Theory Perspective on Human and Humanoid Walking

PubMed Central

Iosa, Marco; Morone, Giovanni; Paolucci, Stefano

2017-01-01

Human walking is a complex task which includes hundreds of muscles, bones and joints working together to deliver harmonic movements with the need of finding equilibrium between moving forward and maintaining stability. Many different computational approaches have been used to explain human walking mechanisms, from pendular model to fractal approaches. A new perspective can be gained from using the principles developed in the field of Optimization theory and in particularly the branch of Game Theory. In particular we provide a new insight into human walking showing as the trade-off between advancement and equilibrium managed during walking has the same solution of the Ultimatum game, one of the most famous paradigms of game theory, and this solution is the golden ratio. The golden ratio is an irrational number that was found in many biological and natural systems self-organized in a harmonic, asymmetric, and fractal structure. Recently, the golden ratio has also been found as the equilibrium point between two players involved into the Ultimatum Game. It has been suggested that this result can be due to the fact that the golden ratio is perceived as the fairest asymmetric solution by the two players. The golden ratio is also the most common proportion between stance and swing phase of human walking. This approach may explain the importance of harmony in human walking, and provide new perspectives for developing quantitative assessment of human walking, efficient humanoid robotic walkers, and effective neurorobots for rehabilitation. PMID:29311890

Modeling Late-Summer Distribution of Golden Eagles (Aquila chrysaetos) in the Western United States

PubMed Central

Gardner, Grant

2016-01-01

Increasing development across the western United States (USA) elevates concerns about effects on wildlife resources; the golden eagle (Aquila chrysaetos) is of special concern in this regard. Knowledge of golden eagle abundance and distribution across the western USA must be improved to help identify and conserve areas of major importance to the species. We used distance sampling and visual mark-recapture procedures to estimate golden eagle abundance from aerial line-transect surveys conducted across four Bird Conservation Regions in the western USA between 15 August and 15 September in 2006–2010, 2012, and 2013. To assess golden eagle-habitat relationships at this scale, we modeled counts of golden eagles seen during surveys in 2006–2010, adjusted for probability of detection, and used land cover and other environmental factors as predictor variables within 20-km2 sampling units randomly selected from survey transects. We found evidence of positive relationships between intensity of use by golden eagles and elevation, solar radiation, and mean wind speed, and of negative relationships with the proportion of landscape classified as forest or as developed. The model accurately predicted habitat use observed during surveys conducted in 2012 and 2013. We used the model to construct a map predicting intensity of use by golden eagles during late summer across our ~2 million-km2 study area. The map can be used to help prioritize landscapes for conservation efforts, identify areas where mitigation efforts may be most effective, and identify regions for additional research and monitoring. In addition, our map can be used to develop region-specific (e.g., state-level) density estimates based on the latest information on golden eagle abundance from a late-summer survey and aid designation of geographic management units for the species. PMID:27556735

Modeling Late-Summer Distribution of Golden Eagles (Aquila chrysaetos) in the Western United States.

PubMed

Nielson, Ryan M; Murphy, Robert K; Millsap, Brian A; Howe, William H; Gardner, Grant

2016-01-01

Increasing development across the western United States (USA) elevates concerns about effects on wildlife resources; the golden eagle (Aquila chrysaetos) is of special concern in this regard. Knowledge of golden eagle abundance and distribution across the western USA must be improved to help identify and conserve areas of major importance to the species. We used distance sampling and visual mark-recapture procedures to estimate golden eagle abundance from aerial line-transect surveys conducted across four Bird Conservation Regions in the western USA between 15 August and 15 September in 2006-2010, 2012, and 2013. To assess golden eagle-habitat relationships at this scale, we modeled counts of golden eagles seen during surveys in 2006-2010, adjusted for probability of detection, and used land cover and other environmental factors as predictor variables within 20-km2 sampling units randomly selected from survey transects. We found evidence of positive relationships between intensity of use by golden eagles and elevation, solar radiation, and mean wind speed, and of negative relationships with the proportion of landscape classified as forest or as developed. The model accurately predicted habitat use observed during surveys conducted in 2012 and 2013. We used the model to construct a map predicting intensity of use by golden eagles during late summer across our ~2 million-km2 study area. The map can be used to help prioritize landscapes for conservation efforts, identify areas where mitigation efforts may be most effective, and identify regions for additional research and monitoring. In addition, our map can be used to develop region-specific (e.g., state-level) density estimates based on the latest information on golden eagle abundance from a late-summer survey and aid designation of geographic management units for the species.

Population characteristics of golden retriever lifetime study enrollees.

PubMed

Simpson, Melissa; Searfoss, Erin; Albright, Sharon; Brown, Diane E; Wolfe, Barbara; Clark, Nancy K; McCann, Susan E; Haworth, David; Guy, Mike; Page, Rod

2017-01-01

Studying cancer and other diseases poses a problem due to their protracted and multifactorial nature. Prospective studies are useful to investigate chronic disease processes since collection of lifestyle information, exposure data and co-incident health issues are collected before the condition manifests. The Golden Retriever Lifetime Study is one of the first prospective studies following privately-owned dogs throughout life to investigate the incidence and risk factors for disease outcomes, especially cancer.Owners of golden retrievers in the contiguous United States volunteered their dogs in early life. Owners and veterinarians complete online questionnaires about health status and lifestyle; dogs undergo a physical examination and collection of biological samples annually. The data presented summarize the initial study visits and the corresponding questionnaires for 3044 dogs in the cohort. The median age of dogs at enrollment was 14.0 months (interquartile range (IQR): 8-20 months). Approximately half of the population had undergone gonadectomy by their initial study visit. Medical conditions reported at enrollment consisted primarily of integumentary, gastrointestinal and urinary dysfunction. A large majority of the dogs have a record of having received preventive care (vaccines, parasiticides, flea and heartworm prevention) by the time of the initial study visit. Clinical pathology data were unremarkable. This study represents one of the first lifetime observational investigations in veterinary medicine. The population characteristics reported here indicate a healthy cohort of golden retrievers cared for by owners committed to their dogs' health. Data acquired over the study period will provide valuable information about genetic, dietary and environmental risk factors associated with disease in golden retrievers and a framework for future prospective studies in veterinary medicine.

Interactions of an insecticide with competition and pond drying in amphibian communities

USGS Publications Warehouse

Boone, M.D.; Semlitsch, R.D.

2002-01-01

Amphibian populations are often imbedded in agricultural landscapes. Therefore the potential for contamination of their habitat is considerable. Our study examined the effects of an insecticide (carbaryl, a neurotoxin), on larval amphibian communities experiencing natural stresses of competition for resources, predation, and pond drying. In a set of experimental ponds, tadpoles of three anuran species (southern leopard frog [Rana sphenocephala], plains leopard frog [R. blairi], and the Woodhouse's toad [Bufo woodhousii]) were added to 1000-L ponds containing leaf litter, plankton, two newts (Notophthalmus viridescens), and four overwintered green frog (R. clamitans) tadpoles. We manipulated the overall tadpole density (low or high), pond hydroperiod (constant or drying), and chemical exposure (0, 3.5, 5.0, or 7.0 mg/L carbaryl) of the ponds. We measured mass, time, and survival to metamorphosis to determine treatment effects. Carbaryl positively affected Woodhouse's toad survival, although it had a negligible effect on both leopard frog species. Tadpole density interacted with the chemical treatment: Proportionately more Woodhouse's toads survived to metamorphosis in high-density environments than in low-density or control environments. Greater survival may be an indirect effect of increased algal food resources from carbaryl exposure. Most newts lost mass over the course of the experiment, although ponds with drying hydroperiods and high anuran density were the least favorable environments. Overwintered green frogs exposed to carbaryl had longer larval periods on average than did green frogs in control ponds. Our study demonstrated that even sublethal, short-lived contaminants can alter natural communities in ways that cannot be predicted from simple, one-factor studies.

Distribution and environmental limitations of an amphibian pathogen in the Rocky Mountains, USA

USGS Publications Warehouse

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

2008-01-01

Amphibian populations continue to be imperiled by the chytrid fungus (Batrachochytrium dendrobatidis). Understanding where B. dendrobatidis (Bd) occurs and how it may be limited by environmental factors is critical to our ability to effectively conserve the amphibians affected by Bd. We sampled 1247 amphibians (boreal toads and surrogates) at 261 boreal toad (Bufo boreas) breeding sites (97 clusters) along an 11?? latitudinal gradient in the Rocky Mountains to determine the distribution of B. dendrobatidis and examine environmental factors, such as temperature and elevation, that might affect its distribution. The fungus was detected at 64% of all clusters and occurred across a range of elevations (1030-3550 m) and latitudes (37.6-48.6??) but we detected it in only 42% of clusters in the south (site elevations higher), compared to 84% of clusters in the north (site elevations lower). Maximum ambient temperature (daily high) explained much of the variation in Bd occurrence in boreal toad populations and thus perhaps limits the occurrence of the pathogen in the Rocky Mountains to areas where climatic conditions facilitate optimal growth of the fungus. This information has implications in global climate change scenarios where warming temperatures may facilitate the spread of disease into previously un- or little-affected areas (i.e., higher elevations). This study provides the first regional-level, field-based effort to examine the relationship of environmental and geographic factors to the distribution of B. dendrobatidis in North America and will assist managers to focus on at-risk populations as determined by the local temperature regimes, latitude and elevation.

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