WorldWideScience
 
 
1

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

DEFF Research Database (Denmark)

The European natterjack toad (Bufo calamita) has declined rapidly in recent years, primarily due to loss of habitat, and in Denmark it is estimated that 50% of the isolated populations are lost each decade. To efficiently manage and conserve this species and its genetic diversity, knowledge of the genetic structure is crucial. Based on nine polymorphic microsatellite loci, the genetic diversity, genetic structure and gene flow were investigated at 12 sites representing 5-10% of the natterjack toad localities presently known in Denmark. The expected heterozygosity (H E) within each locality was generally low (range: 0.18-0.43). Further analyses failed to significantly correlate genetic diversity with population size, degree of isolation and increasing northern latitude, indicating a more complex combination of factors in determining the present genetic profile. Genetic differentiation was high (overall ? = 0.29) and analyses based on a Bayesian clustering method revealed that the dataset constituted 11 geneticclusters, defining nearly all sampling sites as distinct populations. Contemporary gene flow among populations was undetectable in nearly all cases, and the failure to detect a pattern of isolation by distance within major regions supported this apparent lack of a gene flow continuum. Indications of a genetic bottleneck were found in three populations. The analyses suggest that the remaining Bufo calamita populations in Denmark are genetically isolated, and represent independent units in a highly fragmented gene pool. Future conservation management of this species is discussed in light of these results.

Allentoft, Morten E.; Siegismund, Hans Redlef

2009-01-01

2

Thyroid anatomy and topography of toad (Bufo marinus ictericus)  

International Nuclear Information System (INIS)

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

3

Abundance and Breeding Migration of the Asian Toad (Bufo gargarizans)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We monitored a breeding population of the Asian toad (Bufo gargarizans), in the Wonheunge pondat Sannamdong, Chungju, from 5 March to 11 April, 2006 and 14 February to 31 March, 2007 to investigate theirmovement patterns, breeding population sizes, and physical characteristics. Terrestrial migration to the pondstarted on 5 March in 2006 and 14 February in 2007. We captured a total of 266 immigrating individuals (213males, 53 females) in 2006 and 307 (222 males, 85 females) in 2007, and found ...

Sung, Hacheol; Oanhee Park; Sukyung Kim; Daesik Park*; Shi-Ryong Park

2007-01-01

4

An Extraordinary New Toad (Bufo) ttom Costa Rica  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new species of toad, Bufo periglenes, is described from the Lower Montane Rainforest zone of the Cordillera de Tilarán on the divide between Puntarenas and AlajueIa provinces, Costa Rica. The new form exhibits a combination of extremely bright coloration and marked sexual dichromism. Males are solid orange, females greenish to black with scarlet spots. The species lacks a tympanum and columella and is voiceless. Tadpoles are described. Relationships and the role of sexual dichromism are di...

Savage, Jay M.

2002-01-01

5

Diazinon mediated biochemical changes in the African toad (Bufo regularis  

Directory of Open Access Journals (Sweden)

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

Uche Ochei

2012-12-01

6

Abundance and Breeding Migration of the Asian Toad (Bufo gargarizans  

Directory of Open Access Journals (Sweden)

Full Text Available We monitored a breeding population of the Asian toad (Bufo gargarizans, in the Wonheunge pondat Sannamdong, Chungju, from 5 March to 11 April, 2006 and 14 February to 31 March, 2007 to investigate theirmovement patterns, breeding population sizes, and physical characteristics. Terrestrial migration to the pondstarted on 5 March in 2006 and 14 February in 2007. We captured a total of 266 immigrating individuals (213males, 53 females in 2006 and 307 (222 males, 85 females in 2007, and found 50 adults apparently killedby motor vehicles while migrating to the pond in 2007. Emigration from the pond to terrestrial sites started on15 March 2006 and 5 March 2007. We captured a total of 245 emigrating toads (181 males, 65 females in2006 and 99 (92 males, 7 females in 2007. An additional 10 emigrating adults were found dead on the road.During both the immigration and emigration periods, two peaks in capture frequency appeared for each sex ineach breeding season. The immigration peaks corresponded with higher temperatures, while the emigrationpeaks corresponded with high humidity. Migrating Asian toads showed sexual size dimorphism and a malebiasedsex ratio. Body weights and SVL (snout-vent length of immigrating and emigrating individuals werenegatively related with migration dates.

Sung, Hacheol

2007-11-01

7

An Extraordinary New Toad (Bufo ttom Costa Rica  

Directory of Open Access Journals (Sweden)

Full Text Available A new species of toad, Bufo periglenes, is described from the Lower Montane Rainforest zone of the Cordillera de Tilarán on the divide between Puntarenas and AlajueIa provinces, Costa Rica. The new form exhibits a combination of extremely bright coloration and marked sexual dichromism. Males are solid orange, females greenish to black with scarlet spots. The species lacks a tympanum and columella and is voiceless. Tadpoles are described. Relationships and the role of sexual dichromism are discussedSe describe una nueva especie de sapo, Bufo periglenes, del bosque montano bajo pluvial de la Cordillera de Tilarán en la divisoria entre las provincias de Puntarenas y Alajuela, Costa Rica. La nueva especie presenta una evidente combinación de colores brillantes y marcado dicromatismo sexual. Los machos son de un color anaranjado intenso uniforme, las hembras verdusco a negro con manchas rojo escarlata. Esta especie carece de tímpano, columela y voz. Se describen los renacuajos. Se discute el parentesco y el papel del dicromatismo sexual

Jay M Savage

2002-06-01

8

An Extraordinary New Toad (Bufo) ttom Costa Rica  

Scientific Electronic Library Online (English)

Full Text Available SciELO Costa Rica | Language: English Abstract in spanish Se describe una nueva especie de sapo, Bufo periglenes, del bosque montano bajo pluvial de la Cordillera de Tilarán en la divisoria entre las provincias de Puntarenas y Alajuela, Costa Rica. La nueva especie presenta una evidente combinación de colores brillantes y marcado dicromatismo sexual. Los m [...] achos son de un color anaranjado intenso uniforme, las hembras verdusco a negro con manchas rojo escarlata. Esta especie carece de tímpano, columela y voz. Se describen los renacuajos. Se discute el parentesco y el papel del dicromatismo sexual Abstract in english A new species of toad, Bufo periglenes, is described from the Lower Montane Rainforest zone of the Cordillera de Tilarán on the divide between Puntarenas and AlajueIa provinces, Costa Rica. The new form exhibits a combination of extremely bright coloration and marked sexual dichromism. Males are sol [...] id orange, females greenish to black with scarlet spots. The species lacks a tympanum and columella and is voiceless. Tadpoles are described. Relationships and the role of sexual dichromism are discussed

Jay M, Savage.

2002-06-01

9

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

Science.gov (United States)

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 level of the Western Palearctic, our dating estimates place most of the deepest phylogenetic structure before the Pleistocene, indicating that Pleistocene glaciations did not have a major role in splitting the major lineages. At a shallow level, the glacial dynamics contributed unevenly to the genetic structuring of populations, with a strong influence in the European-Caucasian populations, and a more relaxed effect in the Iberian populations. PMID:22214922

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

2012-04-01

10

Accumulation and depuration of trace metals in southern toads, Bufo terrestris, exposed to coal combustion waste.  

Science.gov (United States)

Accumulation and depuration of metals by an organism are underrepresented in the literature. We collected southern toads (Bufo terrestris) from coal by-product (ash)-contaminated and uncontaminated sites to examine metal concentrations over time. Toads were placed in four exposure regimes, then sacrificed periodically over a 5-month period, and whole-body metal levels were measured. Toads exposed to ash accumulated significant concentrations of metals. Metal concentrations changed throughout the experiment, and profiles of accumulation and depuration differed depending on the metal and exposure regime. Ash-exposed toads exhibited elevated levels of 11 of 18 metals measured. Increases ranged from 47.5% for Pb to more than 5000% for As. Eight of 18 metals did not change in control toads, while 10 of 18 metals decreased in toads removed from ash, ranging from -25% for Co to -96% for Tl. Seven metals that decreased in toads removed from ash did not change in control toads. PMID:18491174

Ward, Chelsea; Hassan, Sayed; Mendonça, Mary

2009-02-01

11

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

Science.gov (United States)

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

12

SEXUAL DIFFERENCES IN THE ECOLOGY AND HABITAT SELECTION OF WESTERN TOADS (BUFO BOREAS IN NORTHEASTERN OREGON  

Directory of Open Access Journals (Sweden)

Full Text Available Several species of toads (family Bufonidae, including the Western Toad (Bufo boreas have declined in thewestern United States. Information on toad ecology and habitat use is essential to determine potential causes for populationdeclines, as is the potential relationship between this information and disturbance events. Aspects of western toad survival,mortality, movements, habitat selection, and diet were investigated at five study areas in northeastern Oregon duringsummers of 2002-2005. Of 100 radio-tagged toads monitored for one summer during these years, 32% survived untilSeptember, 29% were killed by predators, 10% died of other causes, and 29% were missing or had lost transmitters. Atfour study areas sampled in 2005, 24% of 37 males and 44% of 32 females sampled during the breeding season, and threedead male toads found after the breeding season tested positive for Batrachochytrium dendrobatidis. Females traveledsignificantly farther than males, and the maximum distances traveled by female and male toads were 6230 m and 3870 m,respectively. Toads with transmitters selected habitats: (1 with little or no canopy; (2 on south-facing slopes; (3 nearwater; and (4 with high densities of potential refugia (e.g., burrows, rocks, logs. Males were more closely associated withwater than females. Twenty-six toads overwintered in rodent burrows (38%, under large rocks (27%, under logs or rootwads (19%, and under banks adjacent to streams or a lake (15%. Diet consisted of 82% ants (Formicidae, 13% beetles(Coleoptera, and <1% in 8 additional orders of insects with no differences detected between male and female toads.Disturbance events, such as wildfire, can influence refugia and prey of toads, and climatic conditions may influence a toad’ssusceptibility to B. dendrobatidis.

EVELYN L. BULL

2006-09-01

13

Effects of spirotetramat on the acute toxicity, oxidative stress, and lipid peroxidation in Chinese toad (Bufo bufo gargarizans) tadpoles.  

Science.gov (United States)

The aim of this work was to evaluate the potential effects of antioxidant and lipid peroxidation parameters as indicators of exposure to spirotetramat and effects of acute toxicity in the Chinese toad Bufo bufo gargarizans. The results of an acute toxicity test showed that the 72 and 96 h median lethal concentrations (LC(50)) of spirotetramat for tadpoles were 6.98 and 6.45 mg/L, respectively. It indicated that the spirotetramat was moderate toxicity to Chinese toad tadpoles. In a sub-lethal toxicity test, the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) contents were determined after exposure to 0.03, 0.06, 0.13, 0.65, and 3.23 mg/L for 4, 15, and 30 days. SOD activity significantly in all experimental groups except the highest concentration group increased on day 4 but decreased on days 15 compared with that of the acetone control (P spirotetramat caused oxidative stress and lipid peroxidation in B. gargarizans tadpoles. These results indicate that sub-lethal even non-lethal spirotetramat are potentially toxic to amphibians. The information presented in this study will be helpful for understanding oxidative stress induced by spirotetramat in aquatic organisms. PMID:24835551

Yin, XiaoHui; Jiang, ShengJu; Yu, Jun; Zhu, GuoNian; Wu, HuiMing; Mao, ChenLei

2014-05-01

14

Elevated trace element concentrations in southern toads, Bufo terrestris, exposed to coal combustion waste.  

Science.gov (United States)

A number of recent studies have linked developmental, physiological, and behavioral abnormalities in amphibians to coal combustion wastes (coal ash). Few studies, however, have determined trace element concentrations in amphibians exposed to coal ash. In the current study we compare total body concentrations of 20 trace elements in adult southern toads, Bufo terrestris, inhabiting coal ash settling basins with toads that were not exposed to the combustion wastes (reference). In addition, we document the accumulation of trace elements in toads transplanted from reference sites to field enclosures in an ash settling basin for 7 and 12 weeks. Arsenic, selenium, and vanadium levels were significantly elevated in toads captured at the ash-contaminated site in comparison to toads from the reference site. All three of these elements were also significantly elevated in toads exposed to the contaminated habitat for only 7 weeks. Our study suggests that adult anurans can bioaccumulate particularly high levels of selenium and may be useful bioindicators in agricultural and coal ash-impacted habitats. PMID:9680525

Hopkins, W A; Mendonça, M T; Rowe, C L; Congdon, J D

1998-08-01

15

Metabolic measures of male southern toads (Bufo terrestris) exposed to coal combustion waste.  

Science.gov (United States)

Southern toads (Bufo terrestris) are found in coal fly ash collection basins associated with coal-burning electrical power plants. These basins contain large amounts of trace metals and organisms found in these basins are known to accumulate large quantities of metals. Studies on a variety of organisms exposed to trace metals found that they experience a significant increase in standard metabolic rate. We experimentally exposed southern toads to metal-contaminated sediment and food and measured changes in standard and exercise metabolic rates as well as changes in body, liver and muscle mass, blood glucose, and corticosterone. We found that toads exposed to trace metal contamination gained significantly less mass (18.3 %) than control toads (31.3%) when food was limited and experienced significantly decreased RQ after exercise. However, contaminated toads did not experience changes in standard (x control = 0.114 +/- 0.016 mL O2 g(-1) h(-1); x (ash)=0.109 +/- 0.013 mL O2 g(-1) h(-1), p = 0.08) or exercise metabolic rates (x control = 0.53 +/- 0.06 mL O2 g(-1) h(-1); x ash =0.44 +/- 0.04 mL O2 g(-1) h(-1), p = 0.47) plasma glucose levels (p = 0.6), and hepatic or muscle percentage indices (p > 0.2 in all cases) whether food was limited or not. PMID:16448834

Ward, Chelsea K; Appel, Arthur G; Mendonça, Mary T

2006-03-01

16

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract 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. Cons...

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

2006-01-01

17

Histopathological Alterations in the Liver and Kidney of Toads (Bufo regularis Intoxicated with a Pyrethroid Insecticide  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of the pyrethroid insecticide, fenvalerate, on the liver and kidney of toad (Bufo regularis was studied. Feeding toads with a daily dose of fenvalerate (0.5 mg/kg body weight for three weeks caused histopathological alterations in these organs. The normal structural organization of the hepatic acini was impaired, the hepatocytes showed cytoplasmic vacuolation, the blood vessels were congested and there was remarkable abundance of leucocytic infiltrations. In the kidney, the renal tubules were degenerated and the glomeruli were atrophied. Moreover, the transaminases enzymes GOT (glutamate-oxaloacetate transaminase and GPT (glutamate-pyruvate transaminase were elevated in the sera of treated animals. The magnitude of the changes was time-dependent being more prominent after the third week of treatment with fenvalerate.

S. A. Sakr

2002-01-01

18

Purification of toad (Bufo japonicus) gonadotropins and development of their homologous radioimmunoassays  

International Nuclear Information System (INIS)

We obtained three gonadotropin fractions with different electrophoretic mobilities named B1D, B3D and B5D from a glycoprotein fraction of toad (Bufo japonicus) pituitaries by cation exchange chromatography using the fast protein liquid chromatography (FPLC) system, chromatofocusing and gel filtration using the FPLC system. Gonadotropin activity was monitored by two radioreceptor assay (RRA) systems, one using bullfrog testis and bullfrog LH as the source of receptor and radioligand respectively, and the other using toad testis and bullfrog FSH respectively. Although, LH/FSH specificity was not complete in these RRAs, the fraction BID showed a higher potency in LH-RRA than in FSH-RRA, while B3D and B5D showed lower potencies in LH-RRA activity than in FSH-RRA. Furthermore, B1D had an activity to release androgen from the toad testis, while B3D and B5D had slight activities. All these fractions stimulated accumulation of cAMP in testis slices of the toad in vitro. These results suggest that B1D contains LH, and B3D and B5D contain FSH-like gonadotropin. SDS PAGE analysis in combination with immunoblot revealed that B1D was almost pure LH, but B3D seemed to be not homogeneous. Anti-B1D-serum and anti-B3D-serum were raised in rabbits, and radioimmunoassays (RIAs) for B1D and B3D were established. The cross reactivity of B3D and B5D in B1D-RIA was about 30% of B1D, while that of B1D in B3D-RIA was only 3% of B3D and B5D. These RIAs were sensitive enough to measure gonadotr were sensitive enough to measure gonadotropins in plasma samples of Bufo japonicus. (author)

19

Energetics of metamorphic climax in the southern toad (Bufo terrestris).  

Science.gov (United States)

During metamorphic climax, anuran larvae must rely on stored energy because changes in oral and digestive morphology prevent foraging and efficient assimilation. Thus, the time required to store adequate energy for metamorphic climax may set a lower limit on age at which it can occur. Therefore, the amount and type of energy used during metamorphic climax must be determined. To quantify the energetic costs of metamorphic climax in Bufo terrestris, oxygen consumption during climax was measured. Wet mass, dry mass, and lipid mass for a group of individuals at the initiation of climax (forelimb emergence, FL) and for another group at the end of climax (complete tail resorption, TR) were also measured to determine whether lipids were used to fuel metamorphic climax. The total amount of energy used, maintenance costs, and development costs during metamorphic climax varied considerably among individuals. Variation in energy metabolism during climax was not related to differences in energy metabolism during larval development or body mass at initiation of climax. TR individuals were significantly lighter in terms of wet mass and had less body water than FL individuals. However, the two groups did not differ in dry mass or lipid mass. Therefore, lipid catabolism is not a major source of energy during metamorphic climax in B. terrestris. As a result, decreases in age at metamorphosis may not be constrained by the need to store energy in the form of lipids. PMID:12955492

Beck, Christopher W; Congdon, Justin D

2003-11-01

20

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

Science.gov (United States)

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. PMID:25314823

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

2014-09-01

 
 
 
 
21

Body size, nuptial pad size and hormone levels: potential non-destructive biomarkers of reproductive health in wild toads (Bufo bufo).  

Science.gov (United States)

Amphibians are declining and fertility/fecundity are major drivers of population stability. The development of non-destructive methods to assess reproductive health are needed as destructive measures are fundamentally at odds with conservation goals for declining species. We investigated the utility of body size, nuptial pad size and forelimb width as non-destructive biomarkers of internal reproductive physiology, by analysing correlations with commonly used destructive methods in adult male toads (Bufo bufo) from a low human impact and a high human impact site. Principal component analyses revealed that size was the most important variable for explaining inter-individual differences in other measured endpoints, both non-destructive and destructive, except for hormone levels and nuptial pad, which were independent of size. Toads from the LI and the HI site differed in almost all of the measured endpoints; this was largely driven by the significantly smaller size of toads from the HI site. Correlational analyses within sites revealed that size was correlated with several reproductive endpoints in toads from the HI site but not the LI site, indicating a possible limiting effect of size on reproductive physiology. Intersex was observed in 33% of toads from the HI site and incidence was not related to any other measured endpoint. In conclusion, we provide evidence that size is associated with reproductive physiology and that nuptial pad/hormone levels have potential as additional markers due to their independence from size. We also show that human activities can have a negative effect on reproductive physiology of the common toad. PMID:24935780

Orton, Frances; Baynes, Alice; Clare, Frances; Duffus, Amanda L J; Larroze, Severine; Scholze, Martin; Garner, Trenton W J

2014-09-01

22

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

Science.gov (United States)

The parotoid glands of toads (Bufonidae) consist of large aggregations of granular glands located between the otic region of the skull and the scapular region. To determine the circulatory pattern of these glands, we perfused the vascular systems of Bufo alvarius, B. marinus, B. terrestris, and B. valliceps with either India ink or Microfil, a fine latex. The perfused glands were studied by gross dissection, microscopic examination, and histology. The vascular patterns of the parotoid glands were compared to the arrangement of vessels in the dorsal skin of Rana sphenocephala (Ranidae), a frog that lacks parotoid glands. The parotoid glands of the four species of toads are supplied with blood by the lateral and dorsal cutaneous arteries and are drained by one or more branches of the internal jugular vein. The dorsal cutaneous artery supplies most of the blood to the parotoid glands in B. terrestris and B. valliceps. In B. alvarius and B. marinus, both the lateral and dorsal cutaneous arteries serve major roles in the blood supply of the glands. These patterns of blood flow have not been described previously for parotoid glands and conflict with earlier accounts for B. alvarius and B. marinus. The arteries and veins associated with the parotoid glands of toads are present in R. sphenocephala, but are arranged differently. In R. sphenocephala, the lateral cutaneous artery supplies the dorsal and lateral skin posterior to the shoulder region, whereas the dorsal cutaneous artery supplies the skin of the shoulder region. In toads, both the lateral and dorsal cutaneous arteries supply the skin of the shoulder region and ramify into subcutaneous capillaries that surround the secretory units of the parotoid glands. Extensive vasculature presumably is important for delivering cholesterol and other precursor molecules to the parotoid glands, where those compounds are converted into toxins. PMID:15108163

Hutchinson, Deborah A; Savitzky, Alan H

2004-05-01

23

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

DEFF Research Database (Denmark)

Two types of chloride current response to a step-wise hyperpolarization of the toad skin is demonstrated: (1) An "instantaneous" response observed immediately upon voltage change, and (2) a subsequent slow response, the time course of which is sigmoidal. The slow response is due to an increase of a transcellular conductance which is specific to chloride ions. The time constant of the conductance increase is dependent on the amplitude of the transepithelial voltage displacement, the smallest time constants are obtained for the highest amplitudes and are in the order of 30 s. The voltage dependences of the steady-state conductance and the steady-state chloride current reveal that the chloride pathway has maximum conductance for V approximately -80 mV (outside of the skin being negative) and approaches a non-conducting safe for V greater than 0 mV. This strong outward going rectification is a steady-state phenomenon: In skins hyperpolarized for a few minutes, the "instantaneous" I-V curves show that the chloridepathway in the conducting state allows a large inward chloride current (outward chloride flux) to pass in the voltage range 40 mV greater than V greater than 0 mV. Calculations based on a three-compartment model indicate that the strong steady-state chloride current rectification cannot be obtained if only the intracellular chloride concentration and the membrane potentials are allowed to vary ("Goldman-rectification"). It is suggested, therefore, that the premeability of the chloride pathway varies reversibly with the transepithelial potential difference. The variable which controls the chloride permeability may be a membrane potential or the concentration of an intracellular ion.

Larsen, Erik Hviid; Kristensen, P

1978-01-01

24

NaCl adaptation in Rana ridibunda and a comparison with the euryhaline toad Bufo viridis.  

Science.gov (United States)

The physiological adaptation of the frog Rana ridibunda to saline environment was studied. It was found that blood was always hypertonic to the external solution, but at the highest salinity tolerated (i.e. 300 mOsM) the osmotic gradient across the skin was nearly abolished. Water uptake by the living frog remained unchanged, whereas sodium transport across the skin decreased markedly. Neurohypophyseal hormone increased water uptake and sodium transport to levels similar to those in tap water frogs. Water content of the tissues was not affected by saline adaptation, although it varied appreciably under acute conditions. Oxygen consumption increased in dehydrated frogs, but not in adapted ones. The results are discussed and compared to the euryhaline toad Bufo viridis; the importance of high urea levels for high salt adaptation is stressed. PMID:1214128

Katz, U

1975-12-01

25

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

Science.gov (United States)

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 maintained 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. PMID:16783624

Ward, C K; Mendonça, M T

2006-08-01

26

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

DEFF Research Database (Denmark)

The steady-state Cl- current across the skin of Bufo viridis adapted to tap water was found to be rectified. In skins bathed with NaCl Ringer on both sides, a large outward current, carried by influx of Cl-, was observed at a clamping voltage (V) of less than -50 mV (outside of the skin negative). for V = -50 mV the transepithelial Cl- conductance calculated from isotope flux measurements was 2.5 +/- 0.3 mS cm-2, N = 10. When the skin was clamped at + 50 mV the net flux of Cl- was reversed, but Cl- conductance was only 0.3 +/- 0.1 mScm-2. Flux ratio analysis indicated that the potential-activated Cl- conductance carries Cl- ions by way of passive transport. With NaCl Ringer bathing the outer surface of the skin the spontaneous potential was about -30 mV. At this potential the Cl- conductance of the skin was about half of its maximum value. The time course of Cl- current activation following a fast, stepwise change of V from 50 mV to a potential below O mV showed an initial delay of a few seconds, and proceeded with a halftime (T 1/2) which varied as a bell-shaped function of V. The maximum T 1/2 was about 100 s for V = -10 mV in skins exposed to KCl Ringer on the outside. Following adaptation of the toads to a 250 mM-NaCl solution, the fully activated Cl- conductance of the skin was greatly reduced, and the conductance-voltage curve was shifted to the left along the voltage-axis. With NaCl Ringer on the outside the spontaneous potential was about -20 mV, and Cl- conductance activation was possible only outside the physiological range of potentials. The time constant of Cl- conductance activation from closed to fully activated state was more than doubled following salt adaptation of the toads. The active inward Cl- flux disappeared in skins of toads adapted to a 250 mM-NaCl solution, and apparent leakage conductance was reduced. Application of the phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine to skin of fully salt-adapted toads increased the transepithelial Cl- conductance, and the time courses of voltage clamp currents became more like those of water-adapted toads. Apparent leakage conductance was increased.(ABSTRACT TRUNCATED AT 400 WORDS)

Katz, U; Larsen, Erik Hviid

1984-01-01

27

Increased circulating levels of testosterone and corticosterone in southern toads, Bufo terrestris, exposed to coal combustion waste.  

Science.gov (United States)

This study describes an interrenal stress response in adult toads, Bufo terrestris, after exposure to coal combustion waste (characterized by a variety of trace elements). In the first portion of this study, free-ranging male toads captured at the coal ash polluted site exhibited significantly higher circulating levels of corticosterone (B) in both June/July and August than conspecifics captured at uncontaminated sites. In addition, both calling and noncalling males from the polluted site had higher B levels than conspecifics engaged in the same behaviors at reference sites. Testosterone levels were elevated in toads from the polluted site, regardless of capture month or behavioral state, suggesting altered androgen production, utilization, and/or clearance. In the second portion of this study, male toads from reference sites were transplanted to enclosures at the polluted site or an uncontaminated site. Toads held at the polluted site exhibited significant increases in B after 10 days of exposure compared to toads held at the reference site. B levels remained significantly elevated in toads transplanted to the polluted site after 12 weeks. We hypothesize that high concentrations of various trace elements in the polluted site are responsible for these hormonal responses. PMID:9356219

Hopkins, W A; Mendonça, M T; Congdon, J D

1997-11-01

28

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Hanner, R. H.; Ryan, G. B.

1980-01-01

29

Histochemical and structural characterization of egg extra-cellular matrix in bufonid toads, Bufo bufo and Bufotes balearicus: molecular diversity versus morphological uniformity.  

Science.gov (United States)

The extra-cellular matrix of fertilized eggs in the bufonid toads Bufo bufo and Bufotes balearicus was studied to clear the relationships between structural and molecular diversity. Histochemical (PAS, AB pH 2.5 and pH 1.0, Beta-elimination PAS) and lectin-histochemical (Con A, WGA, Succinyl-WGA, PNA, RCA-1, DBA, SBA, AAA, UEA-I, LTA) techniques were used and the observations were made under light and electron microscopy. Both species present a fertilization envelope (FE) and two jelly layers (J1 and J2). The fibers of J2 are shared among the eggs of a clutch in a jelly ribbon. The FE of both species presents neutral glycoproteins, mostly N-linked. In B. bufo there are also residuals of mannose and/or glucose and N-acetylglucosamine. In the FE fibers run parallel to egg's surface or are in bundles or looser hanks with no clear orientation. The J1 layer of both species presents sialosulfoglycoproteins, mostly O-linked, with lactosaminylated, galactosaminylated, glycosaminylated, and fucosylated residuals. A lower amount of galactosaminylated residuals is observed in B. balearicus in respect to B. bufo, whereas the opposite is seen in the amount of fucosylated residuals. The J2 layer is similar in composition to J1 but in B. balearicus there are no glucosaminylated residuals. J layers present fibers and granules that reduce towards J2 . Several microorganisms, in particular blue algae, are observed in the J2 layer of both species. In respect to other species, B. bufo and B. balearicus have a lower number of jelly layers, but a comparable number of glycan types. PMID:25091902

Mentino, Donatella; Mastrodonato, Maria; Rossi, Roberta; Scillitani, Giovanni

2014-11-01

30

Observations on myiasis by the calliphorid, Bufolucilia silvarum, in the eastern American toad (Bufo americanus americanus) from southeastern Wisconsin.  

Science.gov (United States)

Larvae of certain species of blowflies (Calliphoridae) cause myiasis in amphibians which may result in significant mortality, yet there are few reports from North America. In this study, we observed primary myiasis in a population of juvenile eastern American toads (Bufo americanus americanus) collected during May-July 1998 from southeastern Wisconsin (USA). Nine (6%) of 140 toads were infected by the green blow fly (Bufolucilia silvarum) with a mean intensity of 10.5 +/- 7.2 (range = 1-24). Weekly parasite prevalence and mean intensity remained low, ranging from 0-20% and 2 +/- 1.4 to 14 +/- 6, respectively. We found: 1) flies lay eggs on healthy toads, 2) eggs hatch with first instar maggots penetrating under the skin, 3) maggots develop to mature third instars within 5-7 days, 4) maggots leave the host and form pupa within 8-11 days of hatching, and 5) maggots pupate within 7-9 days at room temperature. All infected toads died within 1-2 wk as a result of the infection. The low prevalence observed in this study and other reports of this species from mammalian and bird carcasses indicated that B. silvarum is probably a facultative parasite of toads and other amphibians in the United States. This is the first report of B. silvarum causing myiasis in Wisconsin amphibians and the first report in eastern American toads in the United States. PMID:12238378

Bolek, Matthew G; Coggins, James R

2002-07-01

31

Checklist of helminth parasites of the cane toad Bufo marinus (Anura: Bufonidae) from Mexico.  

Science.gov (United States)

Thirty-four adult cane toads Bufo marinus L. (12 males and 22 females) collected from 2 localities in Mexico (Cerro de Oro and Temascal Dams, Oaxaca) in September 2003 were examined for helminth parasites. In total, 14,749 helminths belonging to 14 taxa were collected. Included were 2 adult digeneans (Choledocystus hepaticus, Mesocoelium monas); 1 larval cestode (an unidentified pseudophyllidean); and 11 nematodes, including 3 species of larvae (Contracaecum sp., Physaloptera sp., Physocephalus sexalatus) and 8 species of adults (Aplectana itzocanensis, Cosmocerca sp., Cruzia morleyi, Ochoterenella digiticauda, Oswaldocruzia sp., Raillietnema sp., Rhabdias americanus, and Rhabdiasfuelleborni). Higher species richness was recorded in B. marinus from Cerro de Oro (12 taxa versus 9 in those from Temascal); hosts from both localities shared 7 taxa. There were 25 new locality records, and 2 taxa were registered in Mexico for the first time. To date, 112 helminth species have been recorded parasitizing B. marinus along its native and introduced range of distribution, with 40.5% of them reported from Mexico. PMID:17918380

Espinoza-Jiménez, Arlett; García-Prieto, Luis; Osorio-Sarabia, David; León-Règagnon, Virginia

2007-08-01

32

Inhibition of Batrachochytrium dendrobatidis Caused by Bacteria Isolated from the Skin of Boreal Toads, Anaxyrus (Bufo) boreas boreas, from Grand Teton National Park, Wyoming, USA  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The chytrid fungus Batrachochytrium dendrobatidis is a significant cause of the worldwide decline in amphibian populations; however, various amphibian species are capable of coexisting with B. dendrobatidis. Among them are boreal toads (Anaxyrus (Bufo) boreas boreas) located in Grand Teton National Park (GTNP) in Wyoming, USA. The purpose of this study was to identify cultivable bacterial isolates from the skin microbiota of boreal toads from GTNP and determine if they were capable of inhibit...

Park, Shawna T.; Collingwood, Amanda M.; Sophie St-Hilaire; Sheridan, Peter P.

2014-01-01

33

Interactive effects of maternal and environmental exposure to coal combustion wastes decrease survival of larval southern toads (Bufo terrestris)  

International Nuclear Information System (INIS)

We conducted a mesocosm study to assess the individual and interactive effects of previous maternal exposure and larval exposure to trace element-laden sediments on southern toads (Bufo terrestris). Previous maternal exposure to coal combustion wastes (CCW) reduced larval survival to metamorphosis up to 57% compared to larvae of unexposed females. Larvae reared on CCW accumulated significant concentrations of trace elements resulting in extended larval periods, reduced growth rates, and reduced mass at metamorphosis. However, the effects were dependent on age of sediments, suggesting the effects of contaminants from CCW may be partially ameliorated over time through the reduced bioavailability of trace elements in aged CCW. Most importantly, maternal exposure to contaminants coupled with larval exposure to fresh CCW interacted to reduce survival to metamorphosis by 85% compared to reference conditions. Our study yields further evidence that disposal of CCW in aquatic basins potentially creates ecological traps for some amphibian populations. - Highlights: ? The interaction of maternal exposure and larval exposure to CCW reduced survival. ? Previous maternal exposure to CCW had a latent effect on survival to metamorphosis. ? Larval southern toads exposed to CCW experienced prolonged larval periods. ? Larval southern toads exposed to CCW had reduced growth rates. ? Larval southern toads exposed to CCW had reduced mass at metamorphosis. - Maternal and environmephosis. - Maternal and environmental exposure to coal combustion wastes interact to decrease survival in larval amphibians.

34

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

Energy Technology Data Exchange (ETDEWEB)

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) pollutant 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.

Ward, C.K.; Fontes, C.; Breuner, C.W.; Mendonca, M.T. [Auburn University, Auburn, AL (USA). Dept. of Biological Science

2007-05-15

35

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-04-01

36

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

Science.gov (United States)

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...

37

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

Science.gov (United States)

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. At least two hypotheses have been proposed: 1) CBG levels may increase in response to a stressor, thereby decreasing the amount of circulating free corticosterone, or 2) CBG levels may decline, making corticosterone available for its role in increased metabolic needs during stress. 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) pollutant stressor. To conduct this study, we first characterized the properties of CBG in southern toads. Toad CBG has a K(d)=20.6+/-1.0 nM and a B(max)=332.2+/-5.1 nmol/L plasma. The rank order potencies for steroid inhibition of tritiated corticosterone are: dihydrotestosterone > corticosterone > progesterone=testosterone > estrogen=dexamethasone. 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. PMID:17428483

Ward, Chelsea K; Fontes, Cristiano; Breuner, Creagh W; Mendonça, Mary T

2007-05-15

38

De novo sequencing of peptides from the parotid secretion of the cane toad, Bufo marinus (Rhinella marina).  

Science.gov (United States)

Amphibian skin secretions are well known as a rich source of bioactive peptides. However, little is known about the presence or role of peptides in the highly toxic, parotid secretion of the cane toad or giant toad, Bufo marinus (Rhinella marina), though small molecule bufadienolides, which act as potent cardiotoxins, have been described. In the current study we used RP-HPLC, MALDI-TOF mass spectrometry and tandem mass spectrometry to analyze and determine the first sequences of peptides from the parotid secretion of B. marinus. We show that peptides in the range of 900-2500 Da are indeed present, however in extremely low abundance. Despite the low abundance, the sequences of 14 peptides were determined, several of which match fragments of larger cellular proteins, yet none share substantial homology with defensive or anti-microbial peptides reported from frog skin secretions. We conclude that peptides are present in the parotid glands of B. marinus only in very low quantities and that they are likely to be breakdown products of proteins involved in cell maintenance. Given these results, we conclude that peptides are unlikely to contribute directly to the high toxicity of the cane toad. PMID:21115026

Rash, Lachlan D; Morales, Rodrigo A V; Vink, Simone; Alewood, Paul F

2011-02-01

39

Interactive effects of maternal and environmental exposure to coal combustion wastes decrease survival of larval southern toads (Bufo terrestris).  

Science.gov (United States)

We conducted a mesocosm study to assess the individual and interactive effects of previous maternal exposure and larval exposure to trace element-laden sediments on southern toads (Bufo terrestris). Previous maternal exposure to coal combustion wastes (CCW) reduced larval survival to metamorphosis up to 57% compared to larvae of unexposed females. Larvae reared on CCW accumulated significant concentrations of trace elements resulting in extended larval periods, reduced growth rates, and reduced mass at metamorphosis. However, the effects were dependent on age of sediments, suggesting the effects of contaminants from CCW may be partially ameliorated over time through the reduced bioavailability of trace elements in aged CCW. Most importantly, maternal exposure to contaminants coupled with larval exposure to fresh CCW interacted to reduce survival to metamorphosis by 85% compared to reference conditions. Our study yields further evidence that disposal of CCW in aquatic basins potentially creates ecological traps for some amphibian populations. PMID:22366480

Metts, Brian S; Buhlmann, Kurt A; Scott, David E; Tuberville, Tracey D; Hopkins, William A

2012-05-01

40

Evolutionary specificity of hydrins, new hydroosmotic neuropeptides: occurrence of hydrin 2 (vasotocinyl-Gly) in the toad Bufo marinus but not in the viper Vipera aspis.  

Science.gov (United States)

Hydrin 2 (vasotocinyl-Gly), a hydroosmotic peptide resulting from differential processing of provasotocin and recently identified in frog neurohypophysis, has been looked for in the pituitary gland of an exotic toad (Bufo marinus) and of a reptile (Vipera aspis). Hydrin 2 has been found in the amphibian but not in the reptile. This result confirms the evolutionary specificity of hydrin 2 that has been identified only in frogs and toads but not in birds and reptiles. Occurrence of hydrin 2 is explained by its regulatory function on the water permeability of the skin of anurans. PMID:2110910

Michel, G; Rouillé, Y; Chauvet, M T; Chauvet, J; Acher, R

1990-05-01

 
 
 
 
41

Effects of inhibition gastric acid secretion on arterial acid-base status during digestion in the toad Bufo marinus.  

Science.gov (United States)

Digestion affects acid-base status, because the net transfer of HCl from the blood to the stomach lumen leads to an increase in HCO3(-) levels in both extra- and intracellular compartments. The increase in plasma [HCO3(-)], the alkaline tide, is particularly pronounced in amphibians and reptiles, but is not associated with an increased arterial pH, because of a concomitant rise in arterial PCO2 caused by a relative hypoventilation. In this study, we investigate whether the postprandial increase in PaCO2 of the toad Bufo marinus represents a compensatory response to the increased plasma [HCO3(-)] or a state-dependent change in the control of pulmonary ventilation. To this end, we successfully prevented the alkaline tide, by inhibiting gastric acid secretion with omeprazole, and compared the response to that of untreated toads determined in our laboratory during the same period. In addition, we used vascular infusions of bicarbonate to mimic the alkaline tide in fasting animals. Omeprazole did not affect blood gases, acid-base and haematological parameters in fasting toads, but abolished the postprandial increase in plasma [HCO3(-)] and the rise in arterial PCO2 that normally peaks 48 h into the digestive period. Vascular infusion of HCO3(-), that mimicked the postprandial rise in plasma [HCO3(-)], led to a progressive respiratory compensation of arterial pH through increased arterial PCO2. Thus, irrespective of whether the metabolic alkalosis is caused by gastric acid secretion in response to a meal or experimental infusion of bicarbonate, arterial pH is being maintained by an increased arterial PCO2. It seems, therefore, that the elevated PCO2, occuring during the postprandial period, constitutes of a regulated response to maintain pH rather than a state-dependent change in ventilatory control. PMID:12829050

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

2003-07-01

42

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The doublesex/male abnormal 3 (dsx/mab-3 or DM) domain gene family involved in sexual development encodes putative transcription factors including a DNA-binding homology motif, the DM domain. We used highly degenerate primers to clone and sequence seven distinct DM related transcription factor (Dmrt) genes from the Asian toad (Bufo gargarizans Cantor, 1842). A database search for the cloned sequences revealed the following percentage identity with the homologous Dmrt genes of the human: BgDmr...

Wen Chen; Liu-wang Nie; Ping-ping Zheng

2007-01-01

43

Variation in Developmental Duration and Metamorphosis of the Green Toad, Bufo viridis in Temporary Ponds as an Adaptation to Desert Environment  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The green toads, Bufo viridis breed in temporary desert ponds of variable duration and exhibit extreme plasticity in the timing of metamorphosis. Pond duration depended on initial depth and frequency of rainfall. Tadpoles in shorter duration ponds metamorphosed earlier than tadpoles in longer duration ponds. The larvae complete their development rapidly before the pond dried, but resulted in small size at metamorphosis. The effects of changing resource availability on the timing of metamorpho...

Hussein H.K.; Darwish, A. D. M.

2000-01-01

44

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

DEFF Research Database (Denmark)

Substitution of chloride in the outside bathing medium of the toad skin with bromide, iodide, nitrate and sulphate leads to a reduction in the apparent exchange diffusion of chloride across this tissue, and also to a reduction of the chloride current recorded during hyperpolarization. A series of inhibitors (thiocyanate, furosemide, phloretin, and acetazolamide) also affects chloride exchange diffusion, hyperpolarization current as well as chloride influx during hyperpolarization. Although in some cases, effects on the short circuit current were also observed none of the effects on chloride transport systems could be explained as secondary effects due to a primary interaction with the sodium transport mechanisms. A correlation was found between the clamping current recorded during hyperpolarization and the efflux of chloride under short circuit conditions with chloride Ringer's on both sides. On the basis of these findings, and the results reported in the previous paper (Hviid Larsen and Kristensen 1977) it is considered probable that the membrane molecules responsible to chloride exchange diffusion under short circuit conditions, are rearranged under the influence of a hyperpolarizing clamping voltage, thereby forming channels allowing charge transferring transport of chloride.

Kristensen, P; Larsen, Erik Hviid

1978-01-01

45

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

Science.gov (United States)

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.

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

1981-01-01

46

Effects of meal size, meal type, body temperature, and body size on the specific dynamic action of the marine toad, Bufo marinus.  

Science.gov (United States)

Specific dynamic action (SDA), the accumulated energy expended on all physiological processes associated with meal digestion, is strongly influenced by features of both the meal and the organism. We assessed the effects of meal size, meal type, body temperature, and body size on the postprandial metabolic response and calculated SDA of the marine toad, Bufo marinus. Peak postprandial rates of O(2) consumption (.V(O2)) and CO(2) production (.V(CO2)) and SDA increased with meal size (5%-20% of body mass). Postprandial metabolism was impacted by meal type; the digestion of hard-bodied superworms (Zophobas larva) and crickets was more costly than the digestion of soft-bodied earthworms and juvenile rats. An increase in body temperature (from 20 degrees to 35 degrees C) altered the postprandial metabolic profile, decreasing its duration and increasing its magnitude, but did not effect SDA, with the cost of meal digestion remaining constant across body temperatures. Allometric mass exponents were 0.69 for standard metabolic rate, 0.85 for peak postprandial .V(O2), and 1.02 for SDA; therefore, the factorial scope of peak postprandial .V(O2) increased with body mass. The mass of nutritive organs (stomach, liver, intestines, and kidneys) accounted for 38% and 20% of the variation in peak postprandial .V(O2) and SDA, respectively. Toads forced to exercise experienced 25-fold increases in .V(O2) much greater than the 5.5-fold increase experience during digestion. Controlling for meal size, meal type, and body temperature, the specific dynamic responses of B. marinus are similar to those of the congeneric Bufo alvarius, Bufo boreas, Bufo terrestris, and Bufo woodhouseii. PMID:12601612

Secor, Stephen M; Faulkner, Angela C

2002-01-01

47

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-12-01

48

The Glycoconjugate Changes of Apoptotic Skeletal Muscle Tissues in Regressing Eurasian Green Toad, Bufo viridis (Amphibia: Anura Tadpole Tail  

Directory of Open Access Journals (Sweden)

Full Text Available In the present study, programmed cell death of skeletal muscle tissues of the regressing tail of Euroasian green toad Bufo viridis (Amphibia: Anura tadpole was investigated with Hematoxylin-eosin (H+E and TUNEL methods in the three groups of different tail lengths. TUNEL stainings indicate that, during the tail regression, apoptotic skeletal muscle tissue constitutes fragmentations and the progression of cell death occurs from the tip and outer of the tail to its base. In addition, muscle cells apoptosis occurs first near the subepidermal fibrolast layer proposed that these cells may interfere the skeletal muscle cells apoptosis during the tail regression. When the of the glycosaminoglycan alterations of these different sizes of shortening tail was analyzed histochemically. After the Alcian Blue-Periodic Acid Schiff`s (AB-PAS sequences at critical electrolyte concentrations and different pH values, we observed carboxylated glycosaminoglycans (i.e., hyaluronic acid, HA are increased in apoptotic muscle cells throughout the tail regression. We concluded that carboxylated glycosaminglycans may play an important role in shortening of the tail via muscle cell apoptosis.

Mesut Sahin

2006-01-01

49

Antibacterial activity of the parotid glands secretions of sudanese indigenous african toad (Bufo spp.)  

International Nuclear Information System (INIS)

The study revealed a well-built first line innate immunity system in Bufo Spp., the skin extracts illustrated a very active antibiotic attitude which inhibited the growth of human pathogenic bacteria species, Escherichia coli (ATCC 19615), staphylococcus aureus(ATCC29213) and streptococcus pyogenes (ATCC25922). Heat treatment of secretion supported the fact that the antibacterial components possess an enzymatic attitude. Gel filtration chromatography accompanied with sensitivity tests against S.aureus showed the existence of four groups responsible for antibacterial activity in the parotoid glands secretions.(Author)

50

Andrew meets Rensch: sexual size dimorphism and the inverse of Rensch's rule in Andrew's toad (Bufo andrewsi).  

Science.gov (United States)

Variation in sexual size dimorphism (SSD) is a widespread phenomenon and is commonly attributed to variation in sex-specific patterns of selection. According to Rensch's rule, SSD increases with increasing body size when males are the larger sex, and decreases when females are the larger sex. Using data from 17 populations of Andrew's toad (Bufo andrewsi), we tested whether the patterns of SSD conform to Rensch's rule. Using field experiments, we also evaluated the hypothesis that sexual selection favours large male body size and that fecundity selection favours large female body size. The results revealed that the degree of SSD increased with increasing mean size in females, consistent with the inverse of Rensch's rule. Although experiments revealed evidence for a large-male mating advantage, selection for large male size was weak at best, and hence unlikely to be an important source of variation in SSD. However, fecundity selection favouring large females was evident, and likely to explain the observed inverse of Rensch's rule. After correcting male and female body size for age differences, the patterns of SSD remained the same, suggesting that the intra- and interpopulational variation in SSD is not driven by sex differences in age structure. Hence, these findings suggest that the strong fecundity selection favouring large females drives the evolution of female-biased SSD in B. andrewsi, providing an explanation for the inverse of Rensch's rule. As such, the study provides an important addition to the small body of literature that uses an intraspecific approach to demonstrate the inverse of Rensch's rule. PMID:25407623

Liao, Wen Bo; Liu, Wen Chao; Merilä, Juha

2015-02-01

51

Failed recruitment of southern toads (Bufo terrestris) in a trace element-contaminated breeding habitat: direct and indirect effects that may lead to a local population sink.  

Science.gov (United States)

We conducted a transplant study in which embryonic southern toads (Bufo terrestris) were held in a site polluted with coal ash (site AB; containing As, Cd, Cr, Cu, Se, and other elements) and a reference site (site R) through hatching and early larval development. To examine the remainder of the larval period, surviving larvae in AB were then transplanted to R and back-transplanted to AB, whereas surviving larvae from R were back-transplanted to R. Survival through early larval development was lower in AB than in R (34% versus 50%). However, site of hatching did not influence traits later in development (larval metabolic rate, larval morphology, duration of larval period, size at metamorphosis, or average hopping distance by metamorphs). Toads that spent the entire larval period in R had high rates of survival (70-94% of individuals transplanted after the embryonic period) regardless of where they spent the embryonic and early larval period. However, toads held in AB for the duration of the larval period suffered 100% mortality. Algal resources were scarce and their trace element concentrations high in AB compared to R, suggesting that mortality of larval toads resulted from a combination of direct toxicity (via sediment- and foodborne exposure) and indirect effects on resource abundance. The study suggests that the widespread practice of disposing of coal ash in open aquatic basins may result in sink habitats for some amphibian populations. PMID:11443372

Rowe, C L; Hopkins, W A; Coffman, V R

2001-04-01

52

Use of lidocaine, propranolol, amiodarone, and verapamil in toad envenoming (genus bufo in dogs  

Directory of Open Access Journals (Sweden)

Full Text Available Toad envenoming in dogs can cause death by cardiac fibrilation (CVF. Traditional therapy consists mainly of atropine and propranolol, the last one used to prevent the CVF, that is preceded by negative ventricular deflections (NVDs in the QRS complex of the electrocardiogram. This study intended to verify, comparatively, the lidocaine, propranolol, amiodarone, and verapamil abilities to prevent CVF in experimentally envenomed dogs. Thirty-six dogs were divided into 6 groups (GL, GP, GA, GV, GST, and GSV with n=6; the dogs were submitted to volatile anaesthesia. The animals of the groups GL, GP, GA, and GV received 0.38g of toad venom through oro-gastric catheter and were treated with the following drugs respectively: lidocaine (4mg/Kg, propranolol (0.1mg/Kg, amiodarone (8mg/Kg, and verapamil (2mg/Kg. These drugs were repeated if NVDs reappeared with cardiac frequency >150, GST was not treated and GSV was just anaesthetized. The following results were obtained: GL, NVDs present in 4 animals, 100% recuperation with 3.66 doses/animal; GP, NVDs present in 2 animals, 100% recuperation with 1.66 dose/animal, with bradycardia at the anaesthetic return; GA, NVDs present in 3 animals, 33.33% recuperation with 1.5 dose/animal; GV, NVDs present in 4 animals, 100% recuperation with 2.16 doses/animal; GST, NVD present in 6 animals, 100% death and GSV, NVDs absent, 100% recuperation. As a conclusion, the anaesthetic proceedings used, did not cause NVDs, the envenoming that was not treated was lethal, and among the antiarrhythmics drugs used, verapamil was the most efficient, as it did not cause any serious bradycardia at the anaesthetic return and did not require repeated administrations. For lidocaine, it was efficient but required various administrations; amiodarone could not prevent the death of 4 animals; propranolol was efficient in relation to NVDs control, but caused serious bradycardia at the anaesthetic return.

M. SAKATE

2001-12-01

53

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

Science.gov (United States)

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. PMID:8387009

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

1993-04-01

54

Environmental context determines nitrate toxicity in Southern toad (Bufo terrestris) tadpoles.  

Science.gov (United States)

Aquatic nitrate contamination has escalated over the past 50 years, primarily due to intensified fertilizer application and sewage production worldwide. Nitrate's role in the decline of amphibian populations remains unclear, although studies suggest that nitrate exposure affects larval development. We exposed Bufo terrestris tadpoles to environmentally relevant nitrate concentrations from Gosner stage 25 through forelimb emergence. Tadpoles were exposed to fluctuating (0-30 mg/L NO(3)-N, alternated three times per week) or constant nitrate concentrations (0, 5, 15, or 30 mg/L NO(3)-N), and effects were compared in two water types: natural spring water and reverse-osmosis filtered water, fortified with electrolytes (RO(e)). We measured growth and developmental rates, survival, time to metamorphosis, metamorph body size, hepatosomatic index, and whole-body thyroxine (T(4)) concentrations at forelimb emergence. Based on our observations, we reached three main conclusions: (1) in constant nitrate, tadpoles in RO(e) water grew faster, and were generally larger with higher or similar T(4) at metamorphosis than tadpoles raised in spring water, irrespective of nitrate concentration, (2) in fluctuating nitrate (flux), there were no differences in time to or size at metamorphosis in either water type relative to controls; however, mean T(4) concentrations in the flux treatment showed a reversed pattern in the two water types (SP>RO(e)) compared to the general pattern observed with constant nitrate exposure (RO(e)>SP), and (3) the effect of nitrate on growth and development depended on water type. In RO(e) water with high nitrate (RO(e)-30 mg/L NO(3)-N), tadpoles metamorphosed an average of 5 days (13%) earlier than control animals, but were similar in size to controls. However, spring water tadpoles reared in high nitrate (30 mg/L) delayed metamorphosis by 7 days (18%) compared to animals reared in SP-0, and 11 days (32%) compared to tadpoles raised in RO(e)-30. This delayed development allowed SP-30 tadpoles to reach a larger size that was more similar to metamorphs raised in RO(e) water. Based on information from other studies, we conclude that, in RO(e) water, tadpoles exhibited an expected stress response to nitrate (e.g. metamorphosed earlier as nitrate concentration increased). However, we suggest that, in spring water, tadpoles were exposed to additional stressors that decreased growth rate and thyroxine concentrations, and that this effect was modified by nitrate. PMID:16569448

Edwards, Thea M; McCoy, Krista A; Barbeau, Tamatha; McCoy, Michael W; Thro, John Matthew; Guillette, Louis J

2006-06-10

55

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

Scientific Electronic Library Online (English)

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

Wen, Chen; Liu-wang, Nie; Ping-ping, Zheng.

1189-11-01

56

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

International Nuclear Information System (INIS)

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 ?g/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. - Capsule: The effect of cadmium-contaminated soils The effect of cadmium-contaminated soils on hibernating amphibians depends on cadmium concentration and soil composition and moisture

57

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

International Nuclear Information System (INIS)

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

58

Ventilatory behaviors of the toad Bufo marinus revealed by coherence analysis Padrões respiratórios do anfíbio Bufo marinus revelados por análise de coerência  

Directory of Open Access Journals (Sweden)

Full Text Available Breathing in amphibians is a remarkably complex behavior consisting of irregular breaths that may be taken singly or in bouts that are used to deflate and inflate the lungs. The valves at the two outlets of the buccal cavity (nares and glottis need to be finely controlled throughout the bout for the expression of these complex respiratory behaviors. In this study, we use a technique based on the calculation of the coherence spectra between respiratory variables (buccal pressure; narial airflow; and lung pressure. Coherence was also used to quantify the effects of chemoreceptor and pulmonary mechanoreceptor input on narial and glottal valve behavior on normoxic, hypoxic, and hypercapnic toads with both intact and bilaterally sectioned pulmonary vagi. We found a significant reduction in narial coherence in hypoxic vagotomized toads indicating that pulmonary mechanoreceptor feedback modulates narial opening duration. An unexpectedly high coherence between Pl and Pb during non-respiratory buccal oscillations in hypercapnic toads indicated more forceful use of the buccal pump. We concluded that the coherence function reveals behaviors that are not apparent through visual inspection of ventilatory time series.A dinâmica respiratória em anfíbios apresenta um padrão complexo e irregular de episódios respiratórios isolados ou em cadeia utilizados para inflar ou desinflar os pulmões. A dinâmica respiratória depende do controle fino e coordenado das duas saídas da cavidade bucal (glote e válvulas nasais. Neste estudo, utilizamos análise de coerência, uma técnica de análise spectral, para analisar o espectro de coerência entre três variáveis respiratórias: pressão bucal, fluxo de ar nasal e pressão pulmonar. Também quantificamos os efeitos do quimiorreceptor e do mecanorreceptor pulmonar no comportamento da glote e das válvulas nasais em sapos normóxicos, hipóxicos e hipercápnicos com os ramos pulmonares do nervo vago intactos e bilateralmente seccionados. Esta análise revela comportamentos respiratórios não aparentes pelo método tradicional de inspeção visual dos dados. Por exemplo, uma redução significativa da coerência nasal em sapos hipóxicos vagotomizados foi observada, sugerindo a existência de retroalimentação do mecanorreceptor pulmonar que modula a duração da abertura nasal. Uma coerência surpreendentemente alta entre P1 e Pb durante a hipercapnia indica uso mais intenso da bomba bucal. Concluímos que a utilização da função de coerência revela comportamentos não distinguíveis durante a inspeção visual das séries temporais ventilatórias.

F. C. Coelho

2003-02-01

59

Ventilatory behaviors of the toad Bufo marinus revealed by coherence analysis / Padrões respiratórios do anfíbio Bufo marinus revelados por análise de coerência  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A dinâmica respiratória em anfíbios apresenta um padrão complexo e irregular de episódios respiratórios isolados ou em cadeia utilizados para inflar ou desinflar os pulmões. A dinâmica respiratória depende do controle fino e coordenado das duas saídas da cavidade bucal (glote e válvulas nasais). Nes [...] te estudo, utilizamos análise de coerência, uma técnica de análise spectral, para analisar o espectro de coerência entre três variáveis respiratórias: pressão bucal, fluxo de ar nasal e pressão pulmonar. Também quantificamos os efeitos do quimiorreceptor e do mecanorreceptor pulmonar no comportamento da glote e das válvulas nasais em sapos normóxicos, hipóxicos e hipercápnicos com os ramos pulmonares do nervo vago intactos e bilateralmente seccionados. Esta análise revela comportamentos respiratórios não aparentes pelo método tradicional de inspeção visual dos dados. Por exemplo, uma redução significativa da coerência nasal em sapos hipóxicos vagotomizados foi observada, sugerindo a existência de retroalimentação do mecanorreceptor pulmonar que modula a duração da abertura nasal. Uma coerência surpreendentemente alta entre P1 e Pb durante a hipercapnia indica uso mais intenso da bomba bucal. Concluímos que a utilização da função de coerência revela comportamentos não distinguíveis durante a inspeção visual das séries temporais ventilatórias. Abstract in english Breathing in amphibians is a remarkably complex behavior consisting of irregular breaths that may be taken singly or in bouts that are used to deflate and inflate the lungs. The valves at the two outlets of the buccal cavity (nares and glottis) need to be finely controlled throughout the bout for th [...] e expression of these complex respiratory behaviors. In this study, we use a technique based on the calculation of the coherence spectra between respiratory variables (buccal pressure; narial airflow; and lung pressure). Coherence was also used to quantify the effects of chemoreceptor and pulmonary mechanoreceptor input on narial and glottal valve behavior on normoxic, hypoxic, and hypercapnic toads with both intact and bilaterally sectioned pulmonary vagi. We found a significant reduction in narial coherence in hypoxic vagotomized toads indicating that pulmonary mechanoreceptor feedback modulates narial opening duration. An unexpectedly high coherence between Pl and Pb during non-respiratory buccal oscillations in hypercapnic toads indicated more forceful use of the buccal pump. We concluded that the coherence function reveals behaviors that are not apparent through visual inspection of ventilatory time series.

F. C., Coelho; T. L., Baker; N. J., Smatresk.

2003-02-01

60

Toad poisoning in Laos.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe two patients who developed severe illness after eating the skin and eggs of a toad, probably Bufo melanostictus Schneider, in southeastern Laos. One boy died, and one developed a digoxin toxicity-like syndrome with bradycardia and heart failure but survived. A telephone survey of 16 Lao provincial hospitals suggested that toad poisoning occurs in at least six provinces. That 93% of villagers in three villages in southeastern Laos were aware that toads are poisonous but that 51% ha...

Keomany, S.; Mayxay, M; Souvannasing, P.; Vilayhong, C.; Stuart, Bl; Srour, L.; Newton, Pn

2007-01-01

 
 
 
 
61

How complex is the Bufo bufo species group?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 thi...

Arntzen, J. W.; Recuero, E.; Canestrelli, D.; Marti?nez-solano, I.

2013-01-01

62

Inferring the degree of incipient speciation in secondary contact zones of closely related lineages of Palearctic green toads (Bufo viridis subgroup).  

Science.gov (United States)

Reproductive isolation between lineages is expected to accumulate with divergence time, but the time taken to speciate may strongly vary between different groups of organisms. In anuran amphibians, laboratory crosses can still produce viable hybrid offspring >20 My after separation, but the speed of speciation in closely related anuran lineages under natural conditions is poorly studied. Palearctic green toads (Bufo viridis subgroup) offer an excellent system to address this question, comprising several lineages that arose at different times and form secondary contact zones. Using mitochondrial and nuclear markers, we previously demonstrated that in Sicily, B. siculus and B. balearicus developed advanced reproductive isolation after Plio-Pleistocene divergence (2.6 My, 3.3-1.9), with limited historic mtDNA introgression, scarce nuclear admixture, but low, if any, current gene flow. Here, we study genetic interactions between younger lineages of early Pleistocene divergence (1.9 My, 2.5-1.3) in northeastern Italy (B. balearicus, B. viridis). We find significantly more, asymmetric nuclear and wider, differential mtDNA introgression. The population structure seems to be molded by geographic distance and barriers (rivers), much more than by intrinsic genomic incompatibilities. These differences of hybridization between zones may be partly explained by differences in the duration of previous isolation. Scattered research on other anurans suggests that wide hybrid zones with strong introgression may develop when secondary contacts occur <2 My after divergence, whereas narrower zones with restricted gene flow form when divergence exceeds 3 My. Our study strengthens support for this rule of thumb by comparing lineages with different divergence times within the same radiation. PMID:24713825

Dufresnes, C; Bonato, L; Novarini, N; Betto-Colliard, C; Perrin, N; Stöck, M

2014-07-01

63

Expression pattern of glycoconjugates in the Bidderian and ovarian follicles of the Brazilian toad Bufo ictericus analyzed by lectin histochemistry / Padrão de expressão de glicoconjugados nos folículos Bidderianos e ovarianos do sapo brasileiro Bufo ictericus, analisado por histoquímica de lectin  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese O órgão do Bidder e o ovário do sapo Bufo ictericus foram analisados por meio de microscopia de luz, utilizando a coloração pela hematoxilina-eosina (HE) e o método do ácido periódico de Schiff (PAS). A expressão e a distribuição de carboidratos foram verificadas por meio da histoquímica com lectina [...] s, tendo sido utilizadas 8 lectinas com diferentes especificidades para carboidratos (Ulex europaeus (UEA I), Lens culinaris (LCA), Erythrina cristagalli (ECA), Arachis hypogaea (PNA), Ricinus communis (RCA I), Aleuria aurantia (AAA), Triticum vulgaris (WGA) e Glycine maximum (SBA). Os resultados mostraram que a zona pelúcida Bidderiana apresenta resíduos de alfa-mannose, alfa-L-fucose, beta-D-galactose, N-acetilDglicosamine e alfa/beta-N-acetil-galactosamina. As células foliculares Bidderianas mostraram a presença de beta-D-galactose e N-acetil-D-glicosamina. Na matriz de extracelular foram detectados resíduos de alfa-mannose e alfa/beta-N-acetil-galactosamina. Resíduos de alfa-L-fucose, N-acetyl-D-glicosamina e alfa/beta-N-acetil-galactosamina foram evidenciados na zona pelúcida ovariana, enquanto na célula folicular foi detectado o resíduo de alfa-mannose e de N-acetil-D-glicosamina. Assim, a zona pelúcida, em ambos os órgãos, contém resíduos de N-acetil-D-glicosamina e alfa/beta-N-acetil-galactosamina. O resíduo de alfa-L-fucose foi detectado na zona pelúcida de ambos os órgãos, mas utilizando-se diferentes lectinas. Considerando que o resíduo de alfa-D-galactose é ausente no ovário, mas presente no órgão de Bidder, a alfa-D-galactose pode ter um papel importante no controle do desenvolvimento folicular, bloqueando o desenvolvimento dos folículos Bidderianos e impedindo que o órgão de Bidder se transforme em um ovário funcional. Abstract in english The Bidder's organ and ovary of the Brazilian toad Bufo ictericus were studied by light microscopy, using hematoxylin-eosin (HE) and periodic acid Schiff (PAS) staining. The expression and distribution of carbohydrate moieties was analyzed by lectin histochemistry, using 8 lectins with different car [...] bohydrate specificities: Ulex europaeus (UEA I), Lens culinaris (LCA), Erythrina cristagalli (ECA), Arachis hypogaea (PNA), Ricinus communis (RCA I), Aleuria aurantia (AAA), Triticum vulgaris (WGA), and Glycine maximum (SBA). The results showed that the Bidderian zona pellucida presented alpha-mannose, alpha-L-fucose, beta-D-galactose, N-acetyl-D-glucosamine, and alpha/beta-N-acetyl-galactosamine residues. The Bidderian follicular cells showed the presence of beta-D-galactose and N-acetyl-D-glucosamine. In the extracellular matrix, alpha-mannose and alpha/beta-N-acetyl-galactosamine residues were detected. The ovarian zona pellucida showed alpha-L-fucose, N-acetyl-D-glucosamine, alpha/beta-N-acetyl-galactosamine residues, and alpha-mannose and N-acetyl-D-glucosamine residues were detected in the follicular cells. Thus, the zona pellucida in both organs contains N-acetyl-D-glucosamine, and alpha/beta-N-acetyl-galactosamine residues. alpha-L-fucose residues were detected in the zona pellucida of both organs, using different lectins. Considering that beta-D-galactose residue was absent from ovary but present in the Bidder's organ, this sugar residue may play an important role in follicle development, blocking the Bidderian follicles and preventing further development of the Bidder's organ into a functional ovary.

C. F., Farias; R. A., Azevedo; L., Brito-Gitirana.

2006-02-01

64

Expression pattern of glycoconjugates in the Bidderian and ovarian follicles of the Brazilian toad Bufo ictericus analyzed by lectin histochemistry Padrão de expressão de glicoconjugados nos folículos Bidderianos e ovarianos do sapo brasileiro Bufo ictericus, analisado por histoquímica de lectin  

Directory of Open Access Journals (Sweden)

Full Text Available The Bidder's organ and ovary of the Brazilian toad Bufo ictericus were studied by light microscopy, using hematoxylin-eosin (HE and periodic acid Schiff (PAS staining. The expression and distribution of carbohydrate moieties was analyzed by lectin histochemistry, using 8 lectins with different carbohydrate specificities: Ulex europaeus (UEA I, Lens culinaris (LCA, Erythrina cristagalli (ECA, Arachis hypogaea (PNA, Ricinus communis (RCA I, Aleuria aurantia (AAA, Triticum vulgaris (WGA, and Glycine maximum (SBA. The results showed that the Bidderian zona pellucida presented alpha-mannose, alpha-L-fucose, beta-D-galactose, N-acetyl-D-glucosamine, and alpha/beta-N-acetyl-galactosamine residues. The Bidderian follicular cells showed the presence of beta-D-galactose and N-acetyl-D-glucosamine. In the extracellular matrix, alpha-mannose and alpha/beta-N-acetyl-galactosamine residues were detected. The ovarian zona pellucida showed alpha-L-fucose, N-acetyl-D-glucosamine, alpha/beta-N-acetyl-galactosamine residues, and alpha-mannose and N-acetyl-D-glucosamine residues were detected in the follicular cells. Thus, the zona pellucida in both organs contains N-acetyl-D-glucosamine, and alpha/beta-N-acetyl-galactosamine residues. alpha-L-fucose residues were detected in the zona pellucida of both organs, using different lectins. Considering that beta-D-galactose residue was absent from ovary but present in the Bidder's organ, this sugar residue may play an important role in follicle development, blocking the Bidderian follicles and preventing further development of the Bidder's organ into a functional ovary.O órgão do Bidder e o ovário do sapo Bufo ictericus foram analisados por meio de microscopia de luz, utilizando a coloração pela hematoxilina-eosina (HE e o método do ácido periódico de Schiff (PAS. A expressão e a distribuição de carboidratos foram verificadas por meio da histoquímica com lectinas, tendo sido utilizadas 8 lectinas com diferentes especificidades para carboidratos (Ulex europaeus (UEA I, Lens culinaris (LCA, Erythrina cristagalli (ECA, Arachis hypogaea (PNA, Ricinus communis (RCA I, Aleuria aurantia (AAA, Triticum vulgaris (WGA e Glycine maximum (SBA. Os resultados mostraram que a zona pelúcida Bidderiana apresenta resíduos de alfa-mannose, alfa-L-fucose, beta-D-galactose, N-acetilDglicosamine e alfa/beta-N-acetil-galactosamina. As células foliculares Bidderianas mostraram a presença de beta-D-galactose e N-acetil-D-glicosamina. Na matriz de extracelular foram detectados resíduos de alfa-mannose e alfa/beta-N-acetil-galactosamina. Resíduos de alfa-L-fucose, N-acetyl-D-glicosamina e alfa/beta-N-acetil-galactosamina foram evidenciados na zona pelúcida ovariana, enquanto na célula folicular foi detectado o resíduo de alfa-mannose e de N-acetil-D-glicosamina. Assim, a zona pelúcida, em ambos os órgãos, contém resíduos de N-acetil-D-glicosamina e alfa/beta-N-acetil-galactosamina. O resíduo de alfa-L-fucose foi detectado na zona pelúcida de ambos os órgãos, mas utilizando-se diferentes lectinas. Considerando que o resíduo de alfa-D-galactose é ausente no ovário, mas presente no órgão de Bidder, a alfa-D-galactose pode ter um papel importante no controle do desenvolvimento folicular, bloqueando o desenvolvimento dos folículos Bidderianos e impedindo que o órgão de Bidder se transforme em um ovário funcional.

C. F. Farias

2006-02-01

65

The tactile-stimulated startle response of tadpoles: acceleration performance and its relationship to the anatomy of wood frog (Rana sylvatica), bullfrog (Rana catesbeiana), and American toad (Bufo americanus) tadpoles.  

Science.gov (United States)

I described the tactile-stimulated startle response (TSR) of wood frog (Rana sylvatica), bullfrog (Rana catesbeiana), and American toad (Bufo americanus) tadpoles. One purpose was to rank species in terms of maximum acceleration performance. Also, I tested whether anatomical indicators of performance potential were predictive of realized performance. TSRs were elicited in a laboratory setting, filmed at 250 Hz, and digitally analyzed. TSRs began with two, initial body curls during which tadpoles showed a broad spectrum of movement patterns. TSR performance was quantified by maximum linear acceleration and maximum rotational acceleration of the head/body, both of which tended to occur immediately upon initiation of motion (Bullfrog tadpoles had higher maximum acceleration than the other species, but other interspecific differences were not significant. The species' rank order for the anatomical indicator of linear acceleration potential was bullfrog > wood frog > American toad. The species' rank order for the anatomical indicator of rotational acceleration potential was bullfrog > wood frog = American toad. Thus, the anatomical indicators roughly predicted the rank order of interspecific average performance. However, the anatomical indicators did not correlate with individual tadpole performance. Variability in behavioral patterns may obscure the connection between anatomy and performance. This is seen in the current lack of intraspecific correlation between a morphological indicator of acceleration capacity and acceleration performance. PMID:16493644

Eidietis, Laura

2006-04-01

66

The genetics of amphibian declines: 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  

Science.gov (United States)

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.

Bradley, Shaffer H.; Fellers, G.M.; Magee, A.; Randal, Voss S.

2000-01-01

67

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

Science.gov (United States)

Studies on the life cycles and epizootiology of North American frog lung flukes indicate that most species utilize odonates as second intermediate hosts; adult frogs become infected by ingesting odonate intermediate hosts. Newly metamorphosed frogs are rarely infected with these parasites, predominantly because they are gape-limited predators that cannot feed on large intermediate hosts such as dragonflies. We examined the role of the frog diet and potential intermediate hosts in the recruitment of the frog lung fluke, Haematoloechus coloradensis, to metamorphosed northern leopard frogs (Rana pipiens), Woodhouse's toads (Bufo woodhousii), and bullfrogs (Rana catesbeiana) from western Nebraska. Because of the uncertain validity of H. coloradensis as a distinct species from Haematoloechus complexus, morphological characters of both species were reevaluated and the life cycles of both species were completed in the laboratory. The morphological data on H. coloradensis and H. coimplexus indicate that they differ in their oral sucker to pharynx ratio, uterine loop distribution, and placement of vitelline follicles. However, in terms of their life cycles, both species are quite similar in their use of physid snails as first intermediate hosts, a wide range of nonodonate and odonate arthropods as second intermediate hosts, and leopard frogs and toads as definitive hosts. These results indicate that H. coloradensis and H. complexus are generalists at the second intermediate host level and might be able to infect newly metamorphosed leopard frogs and toads by using small nonodonate arthropods more commonly than other frog lung fluke species. Comparisons of population structure of adult flukes in newly metamorphosed leopard frogs indicate that the generalist nature of H. coloradensis metacercariae enables it to colonize young of the year leopard frogs more commonly than other Haematoloechus spp. that only use odonates as second intermediate hosts. In this respect, the generalist nature of H. coloradensis and H. complexus at the second intermediate host level is an avenue for the colonization of young of year frogs. PMID:17539412

Bolek, Matthew G; Janovy, John

2007-04-01

68

Assessing Atrazine-Induced Toxicities in Bufo bufo gargarizans Cantor.  

Science.gov (United States)

Atrazine (AZ), a widely used herbicide has drawn attentions for its potential impacts on amphibians. This study aims to investigate the toxicity of AZ in Bufo bufo gargarizans Cantor (B. bufo gargarizans), a species of toad commonly found in China and countries in East Asia. We treated tadpoles with 0.1, 1, 10 and 100 ?g/L AZ for 85 days and examined related parameters. The results showed that the mortality of the toads in the treatment group increased dramatically in a U-shaped dose-response relationship. The hindlimb extension and metamorphosis rate of the toads were significantly inhibited by AZ at 10 and 100 ?g/L. Under the same condition, there were significant progressive changes in the testicular structures. Moreover, we found that AZ has no significant effects on growth, sex ratios, gonadal morphology, forelimb emergence and histology in the ovaries. Our results support the idea that environmental contaminants including AZ may be relevant to global amphibian decline. PMID:25533566

Sai, Linlin; Wu, Qingbo; Qu, Binpeng; Bo, Cunxiang; Yu, Gongchang; Jia, Qiang; Xie, Lin; Li, Yuezhong; Guo, Qiming; Ng, Jack C; Peng, Cheng

2015-02-01

69

Biometrical Analyses of a Sicilian Green Toad, Bufo siculus (Stöck et al. 2008), Population Living in Sicily (Italy) / Análisis Biométricos del Sapo Verde Siciliano, Bufo siculus (Stöck et al. 2008), Población que Vive en Sicilia (Italia)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Se realizó un estudio morfométrico de la estructura del sapo verde siciliano de la Reserva Natural "Monte Pellegrino" (norte-oeste de Sicilia). Un total de 666 individuos (354 machos y 312 hembras) fueron capturados desde el año 2003 durante la época de reproducción. Se encontraron diferencias estad [...] ísticamente significativas entre los dos sexos, donde el peso corporal fue el mejor parámetro (hasta 92% de clasificación correcta), seguido por la longitud corporal (hasta 90% de clasificación correcta). El uso simultáneo de todos los caracteres examinados solo aumentó un 1% la probabilidad de una correcta discriminación del sexo. En comparación con la dimensión de otras poblaciones de sapos verdes estudiados por otros autores, el tamaño del cuerpo de esta población siciliana resulta elevado, similar a las poblaciones de Córcega y Cerdeña. Es posible que la gran dimensión de la población siciliana pueda deberse al bajo nivel de competencia con anfibios otras especies y/o a la ausencia de una latencia de invierno. Abstract in english Morphometry structure of Sicilian green toad from the Nature Reserve "Monte Pellegrino" (north-western Sicily) was studied. A total of 666 individuals (354 males and 312 females) were captured in 2003 during reproduction period. Meaningful differences have statistically emerged among the two sexes a [...] nd the body weight is the best parameter (up to 92% correct classification), followed by the length of the body (up to 90% correct classification). The simultaneous use of all the examined characters only increases of 1% the probability for correct discrimination of the sex. In comparison to the dimension of other green toad populations studied by other authors, the body size of this sicilian population results elevated, similar to that of Corsica and of Sardinia. It is possible that the high dimension of the Sicilian population is the result of low competition with other amphibians species and/or to the absence of a winter latency.

Mario, Lo Valvo; Gabriele, Giacalone.

2013-06-01

70

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 d...

Caller, Georgina; Brown, Culum

2013-01-01

71

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

International Nuclear Information System (INIS)

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

72

DIET OF THE SOUTHERN TOAD FROM THE SOUTHERN EVERGLADES  

Science.gov (United States)

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

73

ENVENENAMENTO DE CÃES POR BUFADIENOLÍDEOS (Substâncias encontradas na secreção das glândulas paratóides dos sapos do gênero Bufo) POISONING OF DOGS BY BUFADIENOLIDES (SUBSTANCES FOUND IN THE PARATOID GLAND SECRETION OF FROGS OF THE GENUS Bufo)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Os autores estudaram o efeito da aplicação na mucosa bucal de cães, do produto secretado pelas glândulas paratóides de sapos do gênero Bufo. Os cães apresentaram sinais de graves intoxicações, imediatamente após a aplicação do referido produto.

In the present paper, the authors report the effects of toad’s poison...

Lourival Pereira Nunes; Eduardo Cavalheiro Jardim; Paulo Roberto Figueiredo da Silva

2007-01-01

74

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Tonglei Yu; Yanshu Guo

2012-01-01

75

Active urea transport by the skin of Bufo viridis: Amiloride- and phloretin-sensitive transport sites  

International Nuclear Information System (INIS)

Urea is actively transported inwardly (Ji) across the skin of the green toad Bufo viridis. Ji 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 (10-4 M) significantly inhibited Ji in both adapted and unadapted animals and was unaffected by removal of sodium from the external medium. Phloretin (10-4 M) significantly inhibited Ji in adapted animals by 23-46%; there was also a reduction in Ji in unadapted toads at 10-4 and 5 x 10-4 M phloretin. A dose-response study revealed that the concentration of phloretin causing half-maximal inhibition (K1/2) was 5 x 10-4 M for adapted animals. Ji 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 Ji is independent of sodium at Ji is independent of sodium transport

76

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-05-15

77

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract 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...

Phalen David N; Hartigan Ashlie; Šlapeta Jan

2010-01-01

78

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

Science.gov (United States)

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...

79

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

Science.gov (United States)

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...

80

Population admixture and high larval viability among urban toads  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In terms of evolutionary biology, a population admixture of more than two distinct lineages may lead to strengthened genetic variation through hybridization. However, a population admixture arising from artificial secondary contact poses significant problems in conservation biology. In urban Tokyo, a population admixture has emerged from two lineages of Japanese common toad: native Bufo japonicus formosus and nonnative B. japonicus japonicus, of which the latter was introduced in the early 20...

Hase, Kazuko; Nikoh, Naruo; Shimada, Masakazu

2013-01-01

 
 
 
 
81

Endosulfan acute toxicity in Bufo bufo gills: Ultrastructural changes and nitric oxide synthase localization  

International Nuclear Information System (INIS)

Endosulfan is an organochlorine pesticide used in agriculture for a wide range of crops. Endosulfan concentrations of up to 0.7 mg/L can be found in ponds and streams near sprayed agricultural fields. We investigated the short-term toxicity of endosulfan in common toad (Bufo bufo) tadpoles after 24, 48, and 96 h of exposure. Acute toxicity was evaluated at nominal concentrations ranging from 0.01 to 0.6 mg/L: concentrations that could be found after the application of pesticide. Our results show that 0.43 mg/L of endosulfan caused 50% mortality (LC50). The effects of a sublethal endosulfan concentration (0.2 mg/L) on gill apparatus morphology were evaluated by scanning and transmission electron microscopy. Immunohistochemical methods were also applied to detect the expression pattern of the inducible isoform of nitric oxide synthase (iNOS) in the gills using the confocal laser scanner microscope. Exposure to 0.2 mg/L of endosulfan caused an apparent increase in mucus production, the occurrence of secretory vesicles and lamellar bodies, a widening of intercellular spaces and additionally there was evidence of an inflammatory response in the gill apparatus. The morphological alterations occurred after 24 h and were more pronounced after 48 and 96 h of exposure. Altered morphology and increased mucus secretion indicate impaired gas exchange and osmoregulation in the gills. In addition, there was an increase of iNOS expression after 24 and 48 h which may reflecression after 24 and 48 h which may reflect hypoxia and inflammation in the gill epithelium. Our results clearly indicate that short-term exposure to a sublethal concentration of endosulfan, near the high end of the environmental range, disrupts gill morphology and function in B. bufo tadpoles

82

An Electrophoretic Study of Genetic Differentiation in 40 Populations of Bufo japonicus Distributed in Japan  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Electrophoretic analyses of 14 kinds of enzymes and two kinds of blood proteins were made in 525 toads of 40 populations of Bufo japonicus distributed widely in Japan. These populations belong to five subspecies, B. j. montanus, B. j. japonicus (including B. j. formosus and B. j. hokkaidoensis), B. j. torrenticola, B. j. yakushimensis and B. j. miyakonis. The enzymes and blood proteins are controlled by genes at 22 loci. The fixation indexes calculated according to WRIGHT (1978) showed that t...

Kawamura, Toshijiro; Nishioka, Midori; Sumida, Masayuki; ??, ??; ????, ????; Ryuzaki, Masashi

2006-01-01

83

Active urea transport by the skin of Bufo viridis: Amiloride- and phloretin-sensitive transport sites  

Energy Technology Data Exchange (ETDEWEB)

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%; there 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.

Rapoport, J.; Abuful, A.; Chaimovitz, C.; Noeh, Z.; Hays, R.M. (Soroka Medical Center, Beersheva (Israel) Albert Einstein College of Medicine, New York, NY (USA))

1988-09-01

84

ENVENENAMENTO DE CÃES POR BUFADIENOLÍDEOS (Substâncias encontradas na secreção das glândulas paratóides dos sapos do gênero Bufo POISONING OF DOGS BY BUFADIENOLIDES (SUBSTANCES FOUND IN THE PARATOID GLAND SECRETION OF FROGS OF THE GENUS Bufo  

Directory of Open Access Journals (Sweden)

Full Text Available

Os autores estudaram o efeito da aplicação na mucosa bucal de cães, do produto secretado pelas glândulas paratóides de sapos do gênero Bufo. Os cães apresentaram sinais de graves intoxicações, imediatamente após a aplicação do referido produto.

In the present paper, the authors report the effects of toad’s poison in dogs. This is the first case describe in Goiás.

Lourival Pereira Nunes

2007-09-01

85

The importance of glucose for the freezing tolerance/intolerance of the anuran amphibians Rana catesbeiana and Bufo paracnemis A importância da glicose para a tolerância/intolerância ao congelamento dos anfíbios anuros Rana catesbeiana e Bufo paracnemis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several species of terrestrially hibernating frogs, turtles and insects have developed mechanisms, such as increased plasma glucose, anti-freeze proteins and antioxidant enzymes that resist to freezing, for survival at subzero temperatures. In the present study, we assessed the importance of glucose to cryoresistance of two anuran amphibians: the frog Rana catesbeiana and the toad Bufo paracnemis. Both animals were exposed to -2ºC for measurements of plasma glucose levels, liver and muscle g...

Steiner, A. A.; Petenusci, S. O.; Brentegani, L. G.; Branco, L. G. S.

2000-01-01

86

The importance of glucose for the freezing tolerance/intolerance of the anuran amphibians Rana catesbeiana and Bufo paracnemis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several species of terrestrially hibernating frogs, turtles and insects have developed mechanisms, such as increased plasma glucose, anti-freeze proteins and antioxidant enzymes that resist to freezing, for survival at subzero temperatures. In the present study, we assessed the importance of glucose to cryoresistance of two anuran amphibians: the frog Rana catesbeiana and the toad Bufo paracnemis. Both animals were exposed to -2ºC for measurements of plasma glucose levels, liver and muscle g...

Steiner, A. A.; Petenusci, S. O.; Brentegani, L. G.; Branco, L. G. S.

2000-01-01

87

Magnetic orientation of the Common Toad: establishing an arena approach for adult anurans  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Magnetic orientation is a taxonomically widespread phenomenon in the animal kingdom, but has been little studied in anuran amphibians. We collected Common Toads (Bufo bufo during their migration towards their spawning pond and tested them shortly after displacement for possible magnetic orientation in arena experiments. Animals were tested in two different set-ups, in the geomagnetic field and in a reversed magnetic field. To the best of our knowledge, this is the first study testing orientation of adult anurans with a controlled magnetic field of a known strength and alignment. Results After displacement, toads oriented themselves unimodally under the geomagnetic field, following their former migration direction (d-axis. When the magnetic field was reversed, the distribution of bearings changed from a unimodal to a bimodal pattern, but still along the d-axis. The clustering of bearings was only significant after the toads reached the outer circle, 60.5 cm from their starting point. At a virtual inner circle (diameter 39 cm and at the start of the experiment, orientation of toads did not show any significant pattern. Conclusions The experimental set-up used in our study is suitable to test orientation behaviour of the Common Toad. We speculate that toads had not enough time to relocate their position on an internal map. Hence, they followed their former migration direction. Bimodality in orientation when exposed to the reversed magnetic field could be the result of a cue conflict, between magnetic and possibly celestial cues. For maintaining their migration direction toads use, at least partly, the geomagnetic field as a reference system.

Gollmann Günter

2011-03-01

88

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

Science.gov (United States)

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.

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

89

One year in the life of Bufo punctatus: annual patterns of body temperature in a free-ranging desert anuran.  

Science.gov (United States)

The Mojave Desert is characterized by hot dry summers and cold winters. The red-spotted toad (Bufo (Anaxyrus) punctatus) is the predominant anuran species; yet little is known of their thermal histories and strategies to avoid temperature extremes. We measured body temperature (T(b)) in free-ranging adult toads across all four seasons of a year using implanted data loggers. There is marked individual variation in the temperatures experienced by these toads. As expected, toads generally escape extreme seasonal and diel temperature fluctuations. However, our data demonstrate a much wider estimated T(b) range than was previously assumed. Though often for short periods, red-spotted toads do experience T(b) as low as 3.1 degrees C and as high as 39.1 degrees C. All animals showed periods of prolonged thermal stability in cooler months and wider diel oscillations in warmer months. Red-spotted toad thermal history is likely a function of site choice; the exploitation of different refuges results in diverse thermal experiences. These data represent the most complete record of thermal experiences for a desert anuran and reveal greater extremes in body temperature than previously suggested. PMID:18357398

Rausch, Candice M; Starkweather, Peter L; van Breukelen, Frank

2008-06-01

90

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

Directory of Open Access Journals (Sweden)

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

Afonso Lodovico Sinkoc

1997-06-01

91

Origin and genome evolution of polyploid green toads in Central Asia: evidence from microsatellite markers.  

Science.gov (United States)

Polyploidization, which is expected to trigger major genomic reorganizations, occurs much less commonly in animals than in plants, possibly because of constraints imposed by sex-determination systems. We investigated the origins and consequences of allopolyploidization in Palearctic green toads (Bufo viridis subgroup) from Central Asia, with three ploidy levels and different modes of genome transmission (sexual versus clonal), to (i) establish a topology for the reticulate phylogeny in a species-rich radiation involving several closely related lineages and (ii) explore processes of genomic reorganization that may follow polyploidization. Sibship analyses based on 30 cross-amplifying microsatellite markers substantiated the maternal origins and revealed the paternal origins and relationships of subgenomes in allopolyploids. Analyses of the synteny of linkage groups identified three markers affected by translocation events, which occurred only within the paternally inherited subgenomes of allopolyploid toads and exclusively affected the linkage group that determines sex in several diploid species of the green toad radiation. Recombination rates did not differ between diploid and polyploid toad species, and were overall much reduced in males, independent of linkage group and ploidy levels. Clonally transmitted subgenomes in allotriploid toads provided support for strong genetic drift, presumably resulting from recombination arrest. The Palearctic green toad radiation seems to offer unique opportunities to investigate the consequences of polyploidization and clonal transmission on the dynamics of genomes in vertebrates. PMID:25370211

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

2015-03-01

92

Phospholipid transfer activities in toad oocytes and developing embryos  

International Nuclear Information System (INIS)

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 14C-labeled phospholipids and 3H-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 after 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 unferti 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

93

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

Directory of Open Access Journals (Sweden)

Full Text Available We studied the trophic ecology and microhabitat use of the Asiatic toad, Bufo gargarizans Cantor, 1842; Guentheri frog, Rana guentheri (Boulenger, 1882; and the Ricefield frog, Rana limnocharis (Boie, 1834. These three species are common around Nanchong City, in southwestern China, where they live in the same habitat before hibernation. The main objective of this study was to analyze the diets and patterns of coexistence relative to the microhabitat of each species. In the Asiatic toad, based on index of relative importance, the diet was dominated by adult Coleoptera, Isopoda, and Hymenoptera (29.53%, 22.07%, and 15.20%, respectively, while the Guenther's frog and Ricefield frog ingested predominantly Orthoptera (67.44% and 40.94%, respectively. The standardized feeding niche breadth of the Asiatic toad (0.277 was wider than that of the Guentheri frog (0.177 and Ricefield frog (0.269. The overlap in the trophic niche (prey proportion between the toad and two species of frog was low (toad vs. Guentheri frog, C H = 0.526; toad vs. Ricefield frog, C H = 0.521, while this was high for the two species of frogs (C H = 0.942. The three species also differed in microhabitat use. Asiatic toads showed strong preference for small roads close to shrubs or pre-harvest corn, while Guenther's frogs preferred bare surfaces on habitat edges, and Ricefield frogs showed a preference for bare surfaces as feeding sites in the middle of habitat. The difference in diet observed during three species seems to be explained by the difference in microhabitat use and body size of three species.

Tonglei Yu

2012-02-01

94

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english We studied the trophic ecology and microhabitat use of the Asiatic toad, Bufo gargarizans Cantor, 1842; Guentheri frog, Rana guentheri (Boulenger, 1882); and the Ricefield frog, Rana limnocharis (Boie, 1834). These three species are common around Nanchong City, in southwestern China, where they live [...] in the same habitat before hibernation. The main objective of this study was to analyze the diets and patterns of coexistence relative to the microhabitat of each species. In the Asiatic toad, based on index of relative importance, the diet was dominated by adult Coleoptera, Isopoda, and Hymenoptera (29.53%, 22.07%, and 15.20%, respectively), while the Guenther's frog and Ricefield frog ingested predominantly Orthoptera (67.44% and 40.94%, respectively). The standardized feeding niche breadth of the Asiatic toad (0.277) was wider than that of the Guentheri frog (0.177) and Ricefield frog (0.269). The overlap in the trophic niche (prey proportion) between the toad and two species of frog was low (toad vs. Guentheri frog, C H = 0.526; toad vs. Ricefield frog, C H = 0.521), while this was high for the two species of frogs (C H = 0.942). The three species also differed in microhabitat use. Asiatic toads showed strong preference for small roads close to shrubs or pre-harvest corn, while Guenther's frogs preferred bare surfaces on habitat edges, and Ricefield frogs showed a preference for bare surfaces as feeding sites in the middle of habitat. The difference in diet observed during three species seems to be explained by the difference in microhabitat use and body size of three species.

Tonglei, Yu; Yanshu, Guo.

2012-02-01

95

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

Scientific Electronic Library Online (English)

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

Luciana, Sonne; Daniela Bernadete, Rozza; Adriana Nunes, Wolffenbüttel; Adriana Erica Wilkes Burton, Meirelles; Pedro Miguel Ocampos, Pedroso; Eduardo Conceição de, Oliveira; David, Driemeier.

1787-17-01

96

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

Directory of Open Access Journals (Sweden)

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

Luciana Sonne

2008-09-01

97

Presynaptic neuromuscular action of a methanolic extract from the venom of Rhinella schneideri toad  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Background Rhinella schneideri, previously known as Bufo paracnemis, is a common toad in many regions of Brazil. Its venom exerts important cardiovascular effects on humans and other animals. Although this toad venom has been the subject of intense investigations, little is known about its neuromus [...] cular activity. Methods The neurotoxicity of a methanolic extract of R. schneideri venom was tested on mouse phrenic nerve-diaphragm (PND) preparations mounted for conventional twitch tension recording – in response to indirect stimulation – and for electrophysiological measurements. Results Venom extract (50 ?g/mL) increased the muscle twitch tension in PND preparations but did not significantly alter the resting membrane potential values. Electrophysiological evaluations showed that the extract (50 ?g/mL) significantly augmented the frequency of miniature end-plate potential (from 38?±?3.5 to 88?±?15 after 60 minutes; n?=?5; p?

Sandro, Rostelato-Ferreira; Cháriston A Dal, Belo; Gildo B, Leite; Stephen, Hyslop; Léa, Rodrigues-Simioni.

2014-09-02

98

Haematological changes in Bufo maculatus treated with sublethal concentrations of Cadmium  

Directory of Open Access Journals (Sweden)

Full Text Available Adult Bufo maculatus was exposed to sublethal cadmium concentrations of 0.25, 0.50, 1.00 and 2.00 mg/L. The toxicant from which the cadmium concentrations were prepared was cadmium chloride (CdCl2.H2O. There were three replicate tanks per treatment and three individuals per tank including control groups. The hematologic alterations based on the examination of blood indices during the 28 days of exposure showed that total erythrocyte count (TEC, hematocrit (Hct and hemoglobin (Hb concentration decreased (PBufo maculatus toad to cadmium can inflict alterations in the hematologic indices, which could induce unfavorable physiological changes in the amphibian, which may lead to death. There is, therefore, the need to protect amphibians in order to sustain the biodiversity in the Nigerian Niger Delta ecological zone.

Alex Ajeh Enuneku

2011-05-01

99

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

Science.gov (United States)

Glutathione-S-transferase (GST) plays a key role in cellular detoxification of various xenobiotic chemical, especially pesticides. The study was carried out to assess the effects of the organochlorine pesticide, endosulfan and the organophosphate pesticide, diazinon on the activity of GST of different tissues in the African common toad, Bufo regularis. Toads were exposed for 28 days to varying levels of the pesticides: 0.01, 0.02, 0.03 and 0.04 microg L(-1) for the sublethal test. Activity of GST of toads exposed to the pesticides differentially increased significantly with increasing concentrations. The highest enhancement in GST activity was recorded in the liver followed by the brain, serum, GIT and lungs for both pesticide exposures. The differential increase in GST activity was tissue and pesticide specific. Liver GST increased up to 366% in endosulfan exposed toads and 393% in diazinon exposed toads in the highest concentration (0.04 microg L(-1)). Diazinon pesticide from this study proved to be more toxic than endosulfan pesticide. PMID:20609459

Ezemonye, Lawrence; Tongo, Isioma

2010-09-01

100

A Research of Peripheral Blood Cells Annually in Bufo Bufo gargarizans / Investigación de las Células Sanguíneas Periféricas en un Periodo Anual del Bufo Bufo gargarizans  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Se realizó el presente estudio histológico de las células sanguíneas de Bufo Bufo gargarizans en diferentes meses del año: enero, marzo, mayo, julio y octubre. Fueron utilizados métodos de rutina por frotis de sangre con tinción de Wright y observación in vivo. Encontramos dos tipos principales de c [...] élulas de glóbulos rojos al frotis como también en células in vivo: mitóticas y amitóticas. Por cuanto amitosis se produce durante todo el año, sobre todo en el mes de julio, la mitosis hasta el momento se había observado solamente en julio. Además, se encontró una gran cantidad de neutrófilos en los glóbulos de Bufo Bufo gargarizans. Los núcleos de estas células son polimórficos, especialmente en enero y marzo. La concentración de glóbulos rojos era más bajo en mayo y más alta en enero; la concentración de las células blancas de la sangre fue mayor en octubre y menor en marzo. En cuanto a los granulocitos, eosinófilos estos presentaron una mayor proporción en julio y octubre, mientras que los neutrófilos y basófilos registraran una mayor proporción en el mes de julio. Los agranulocitos y las células mononucleares alcanzaron el valor más alto en marzo, y el valor más bajo en enero. Los linfocitos y el valor máximo fue registrado en mayo, el valor más bajo fue registrado en julio. No fueron evidentes los cambios morfológicos de trombocitos, lo que podría tener relación con su estabilidad. Abstract in english The present paper deals with a histological study of the blood cells of Bufo Bufo gargarizans in different months: January, March, May, July and October. The methods used are by routine blood smear in Wright stain and observation in vivo. We found that in smears and in vivo two main types of cells o [...] f the red cells: mitotic as well as amitotic. While amitotic occurs all the year round, particularly in July, mitosis so far had been seen only in July. It is also found that there are plenty of neutrophils in the blood cells of Bufo Bufo gargarizans, furthermore, the nuclei of these cells are polymorphic, especially in January and March. Meanwhile, the concentration of red cells was lowest in May and highest in January; The concentration of white blood cells was highest in October and lowest in March; As to granulocytes, eosinophils in July and October had higher proportion, while neutrophils and basophils in July; in agranulocytes, mononuclear cells reached the highest value in March, lowest in January, lymphocytes and the maximum value appeared in May, the lowest value appeared in July. Morphological changes of thrombocytes were not obvious.

Chongbin, Liu; Chengqiang, Xia; Zhaohui, Xie; Yang, Jiao; Qiusheng, She.

1282-12-01

 
 
 
 
101

The importance of glucose for the freezing tolerance/intolerance of the anuran amphibians Rana catesbeiana and Bufo paracnemis  

Directory of Open Access Journals (Sweden)

Full Text Available Several species of terrestrially hibernating frogs, turtles and insects have developed mechanisms, such as increased plasma glucose, anti-freeze proteins and antioxidant enzymes that resist to freezing, for survival at subzero temperatures. In the present study, we assessed the importance of glucose to cryoresistance of two anuran amphibians: the frog Rana catesbeiana and the toad Bufo paracnemis. Both animals were exposed to -2ºC for measurements of plasma glucose levels, liver and muscle glycogen content, haematocrit and red blood cell volume. Frogs survived cold exposure but toads did not. Blood glucose concentration increased from 40.35 ± 7.25 to 131.87 ± 20.72 mg/dl (P < 0.01 when the frogs were transferred from 20 to -2ºC. Glucose accumulation in response to cold exposition in the frogs was accompanied by a decrease (P < 0.05 in liver glycogen content from 3.94 ± 0.42 to 1.33 ± 0.36 mg/100 mg tissue, indicating that liver carbohydrate reserves were probably the primary carbon source of glucose synthesis whereas muscle carbohydrate seems unimportant. In the toads, the cold-induced hyperglycaemia was less (P < 0.05 pronounced (from 27.25 ± 1.14 to 73.72 ± 13.50 mg/dl and no significant change could be measured in liver or muscle glycogen. Cold exposition had no effect on the haematocrit of the frogs but significantly reduced (P < 0.01 the haematocrit of toads from 20.0 ± 2.1% to 5.8 ± 1.7% due to a decreased red blood cell volume (from 1532 ± 63 to 728 ± 87 mm³. When toads were injected with glucose, blood glucose increased to levels similar to those of frogs and haematocrit did not change, but this failed to make them cryoresistent. In conclusion, the lack of cold-induced glucose catabolism may not be the only mechanism responsible for the freeze intolerance of Bufo paracnemis, a freeze-intolerant species.

STEINER A. A.

2000-01-01

102

Purification of active bufadienolides from toad skin by preparative reversed-phase liquid chromatography coupled with hydrophilic interaction chromatography.  

Science.gov (United States)

An isolation method by reversed-phase liquid chromatography coupled with hydrophilic interaction chromatography was successfully used to isolate and purify active bufadienolides from Bufo bufo gargarizans Cantor toad skin. In the first step, crude samples were run on an XTerra Prep C18 column. After screening for activity, two fractions were chosen for further purification. A Click beta-Cyclodextrin (Click-CD) column made in our laboratory was used for the second step. Seven compounds, including four stereoisomers, were obtained at high purity. The orthogonal isolation method described here was a powerful tool for isolating bufadienolides, including stereoisomers, from a natural product. This integrated method may be useful for the discovery of novel active compounds from natural products. PMID:20432230

Liu, Yanfang; Feng, Jiatao; Xiao, Yuansheng; Guo, Zhimou; Zhang, Jing; Xue, Xingya; Ding, Jin; Zhang, Xiuli; Liang, Xinmiao

2010-06-01

103

Comparative developmental toxicity of nickel to Gastrophryne carolinensis, Bufo terrestris, and Xenopus laevis.  

Science.gov (United States)

The early embryo-larval developmental toxicity of nickel (Ni) to 3 amphibian species, Xenopus laevis (South African clawed frog), Bufo terrestris (southern toad), and Gastrophryne carolinensis (eastern narrow-mouthed toad), was evaluated using a modified FETAX model. Studies were initiated from late blastulae stage (Nieuwkoop and Faber [NF] stage 10 or Gosner stage 12) and completed at a common embryological-based test termination point, which represented the completion of the major stages of organogenesis (NF stage 46 for Xenopus or Gosner stage 26 for the toads). Results indicated that, in terms of lethality, G. carolinensis was the most sensitive and X. laevis was the least sensitive of the species tested. The 4-d LC50 in X. laevis value was approximately 7.2- and 2.8-fold greater than the G. carolinensis and B. terrestris, respectively. In terms of malformation, X. laevis was the most sensitive and B. terrestris was the least sensitive of the species tested. The 7-d EC50 (malformation) in B. terrestris was 10.6- and 7.0-fold greater than X. laevis or G. carolinensis, respectively. The chronic value (ChV) for growth in X. laevis was nearly 4.5-fold less than the ChV for growth determined for B. terrestris. As with the malformation endpoint, X. laevis was more sensitive than the other species, which were nearly equisensitive. Overall, the present study provides new data regarding the toxicity of Ni to larval amphibian species, which may be useful in the establishment of new aquatic life criteria for Ni. PMID:16998636

Fort, Douglas J; Rogers, Robert L; Thomas, John H; Hopkins, William A; Schlekat, Christian

2006-11-01

104

A suspected parasite spill-back of two novel Myxidium spp. (Myxosporea) causing disease in Australian endemic frogs found in the invasive Cane toad.  

Science.gov (United States)

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

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

2011-01-01

105

Two new endemic genera and a new species of toad (Anura: Bufonidae from the Western Ghats of India  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Bufonidae are a large family of toads with a subcosmopolitan distribution. Recent molecular phylogenetic analyses have revealed a radiation of toads (Adenominae with distinct adult and larval ecomorphs on the Southern parts of the Indian subcontinent. The Indian torrential species "Ansonia" ornata has a basal position in this clade and does not group with South-East Asian Ansonia. Additionally, the nested position of "Bufo" koynayensis and an undescribed sister species, and their distinct ecologies including a non-typical egg-laying strategy within bufonids, support the recognition of a second distinct genus. In this paper we describe two new genera and one new species from the Adenominae clade. Findings Ansonia ornata Günther, 1876 "1875" is transferred to Ghatophryne gen. nov., a genus of torrentially adapted toads that are endemic to the Western Ghats of India. On the basis of close morphological resemblance and distribution, Ansonia rubigina Pillai and Pattabiraman, 1981 is provisionally transferred to this new genus. The Western Ghats endemic toad Bufo koynayensis Soman, 1963 is transferred to a new genus Xanthophryne gen. nov. Based on molecular and morphological evidence, we additionally describe a new species, Xanthophryne tigerinus sp. nov., from Amboli in the Western Ghats. Conclusion The descriptions and subsequent taxonomic changes we propose result in three genera of bufonids recognised as being endemic to the Western Ghats (Ghatophryne gen. nov., Xanthophryne gen. nov. and Pedostibes, and one to Sri Lanka (Adenomus. The spatial distribution, and arrangement of these lineages at the base of Adenominae diversification, reflects their Early Neogene isolation in the Western Ghats-Sri Lanka hotspot.

Loader Simon P

2009-12-01

106

NHE-1 sequence and expression in toad, snake and fish red blood cells  

DEFF Research Database (Denmark)

Red blood cells (RBC) from reptiles appear not to express regulatory volume increase (RVI) upon shrinkage (Kristensen et al., 2008). In other vertebrates, the RVI response is primarily mediated by activation of the Na+/H+ exchanger (NHE-1) and we, therefore decided to investigate whether red cells of reptiles express a different NHE-1 that responds less to volume activation compared to other vertebrates or simply lack the Na+/H+ exchanger. Using various tissues from the ball python (Python regius), Cane toad (Bufo marinus) and European perch (Perca fluviatilis), cDNA libraries were created and sequenced using PCR with primers generated from a clustal alignment of available NHE-1 sequences in the NR database. Having established the presence of the NHE-1 gene in python, cane toad and perch, expression was quantified by Western Blot and Immunoconfocal microscopy using fluorophore coupled NHE-1 antibodies. These studies showed that NHE-1 is expressed in RBCs from both toads and teleosts fish, but is not expressed in the RBCs of pythons. Thus, the lack of the RVI response in pythons is likely to reflect the lack of capacity to exchange Na+ and H+ for volume regulation.

Thomsen, Steffen Nyegaard; Wang, Tobias

107

Cardiorespiratory effects of forced activity and digestion in toads.  

Science.gov (United States)

Digestion and physical activity are associated with large and sometimes opposite changes in several physiological parameters. Gastric acid secretion during digestion causes increased levels of plasma bicarbonate ([HCO-3](pl)), whereas activity leads to a metabolic acidosis with increased lactate and decrease in plasma bicarbonate. Here we describe the combined effects of feeding and activity in the toad Bufo marinus to investigate whether the increased bicarbonate buffering capacity during digestion (the so-called alkaline tide) protects the acid-base disturbance during activity and enhances the subsequent recovery. In addition, we describe the changes in arterial oxygen levels and plasma ion composition, as well as rates of gas exchange, heart rates, and blood pressures. Toads were equipped with catheters in the femoral artery and divided into four experimental regimes: control, digestion, forced activity, and forced activity during the postprandial period (N=6 in each). Digestion induced a significant metabolic alkalosis with increased [HCO-3](pl) that was completely balanced by a respiratory acidosis; that is, increased arterial Pco(2) (P(a)co(2)), so that arterial pH (pH(a)) did not change. Forced activity led to a substantial reduction in pH(a) by 0.43 units, an increase in plasma lactate concentration by 12.5 mmol L(-1), and a reduction in [HCO-3](pl) of similar magnitude. While digesting animals had higher P(a)co(2) and [HCO-3](pl) at rest, the magnitude and duration of the changes in arterial acid-base parameters were similar to those of fasting animals, although the reduction in pH(a) was somewhat lower (0.32 units). In conclusion, while recovery from the acidosis following exercise did not seem to be affected by digestion, the alkaline tide did slightly dampen the reduction in pH(a) during activity. PMID:13130426

Andersen, Johnnie Bremholm; Wang, Tobias

2003-01-01

108

Steroid metabolism determines mineralocorticoid specificity in the toad bladder.  

Science.gov (United States)

Edwards et al. (C. R. W. Edwards, P. M. Stewart, D. Burt, L. Brett, M. A. McIntyre, W. S. Sutanto, E. R. de Kloet, and C. Monder, Lancet 2: 986-989, 1988) proposed that 11 beta-hydroxysteroid-dehydrogenase (11 beta-OHSD) plays a key role in the kidney by converting glucocorticoids (cortisol or corticosterone), which display a high affinity for type 1 mineralocorticoid receptors, into their inactive metabolites (cortisone or 11-dehydroxy-corticosterone), thus preventing their illicit occupation of the receptor in the target cell for aldosterone. We have tested this hypothesis in the urinary bladder of Bufo marinus by measuring the sodium transport responses to aldosterone and corticosterone. Aldosterone (10 nM) on the serosal side elicited a quarter of the maximal increase in sodium transport. At the same concentration, corticosterone (10 nM, serosal side) was ineffective. Adding corticosterone (10 nM) on the mucosal side elicited a response equivalent to that of aldosterone, suggesting that corticosterone was inactivated in the serosal or underlying tissue of the toad bladder. Carbenoxolone (10 microM, serosal side), a potent inhibitor of 11 beta-OHSD, did not modify the base-line sodium transport. However, in the presence of carbenoxolone (10 microM, serosal side, 2 h pretreatment) corticosterone (10 nM, serosal side) became as potent as aldosterone in eliciting the mineralocorticoid response. Our data are consistent with the idea that corticosterone is converted into an inactive metabolite in the mucosal and/or submucosal tissue of the toad bladder. These studies are consistent with our concept that 11 beta-OHSD is crucial in protecting the nonspecific mineralocorticoid receptor from glucocorticoid. PMID:2508490

Gaeggeler, H P; Edwards, C R; Rossier, B C

1989-10-01

109

Ventilatory behaviors of the toad Bufo marinus revealed by coherence analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Breathing in amphibians is a remarkably complex behavior consisting of irregular breaths that may be taken singly or in bouts that are used to deflate and inflate the lungs. The valves at the two outlets of the buccal cavity (nares and glottis) need to be finely controlled throughout the bout for the expression of these complex respiratory behaviors. In this study, we use a technique based on the calculation of the coherence spectra between respiratory variables (buccal pressure; narial airfl...

Coelho F. C.; Baker T. L.; Smatresk N. J.

2003-01-01

110

Nematode larvae (order Spirurida) in gastric tissues of Australian anurans: a comparison between the introduced cane toad and sympatric native frogs.  

Science.gov (United States)

The outcomes of host-parasite interactions depend heavily on the host's immune response, which, in turn, is governed by previous interactions between the host and parasite, both over the host's life time and over evolutionary time. In the case of species introductions, such as the cane toad (Bufo marinus) to Australia, parasites that are benign to native species of the introduced range may present a major challenge to the introduced species. Stomachs of introduced cane toads and seven species of sympatric native frogs were examined for parasites, and their pathology and biology were compared. Cane toads were host to eight species of third-stage spirurid larvae, six of which also occurred in the stomach wall of four native frog species. In general, encysted nematode larvae attained higher prevalence and species richness in introduced cane toads than in sympatric native frogs. This trend was largely explained by differences in body sizes: larger anurans were more likely to possess infections, and cane toads are inherently larger than native frogs. Encysted larvae in cane toad stomachs provoked a marked pathologic response. All larvae (physalopterine and Physocephalus spp.) were surrounded by concentric layers of dense, fibrous tissue, with considerable cellular infiltration characterized by lymphocytes and polymorphs. Many cysts were invaded by cells and exudate, which, in more advanced cases, became calcified. Some larvae appeared viable; most were in various stages of destruction, and some smaller Physocephalus spp. were mummified. Conversely, pathologic response observed in native frogs was minimal, with little fibrotic reaction surrounding the cysts, and no cellular infiltration. Presumably, the contrast in pathology between introduced and native hosts reflects the long evolutionary association between these nematode larvae and native frogs, whereas the recent exposure of introduced toads to these helminths provokes a severe reaction. PMID:20966264

Kelehear, Crystal; Jones, Hugh I

2010-10-01

111

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

Energy Technology Data Exchange (ETDEWEB)

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 {mu}g L{sup -1} or 232 {mu}g L{sup -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 {mu}g free-CYN kg{sup -1} fresh weight. This is the first investigation of C. raciborskii exposure effects and toxin bioaccumulation in the developmental stages of an amphibian. - Cane toad tadpoles experienced adverse effects and bioaccumulation of toxin following exposure to the cyanobacterium Cylindrospermopsis raciborskii.

White, S.H. [Freshwater Ecology Group, Centre for Environmental Management, Central Queensland University, Building 6, Bruce Highway, Rockhampton, QLD 4702 (Australia)]. E-mail: s.white@cqu.edu.au; Duivenvoorden, L.J. [Freshwater Ecology Group, Centre for Environmental Management, Central Queensland University, Building 6, Bruce Highway, Rockhampton, QLD 4702 (Australia)]. E-mail: l.duivenvoorden@cqu.edu.au; Fabbro, L.D. [Freshwater Ecology Group, Centre for Environmental Management, Central Queensland University, Building 6, Bruce Highway, Rockhampton, QLD 4702 (Australia)]. E-mail: l.fabbro@cqu.edu.au; Eaglesham, G.K. [Queensland Health Scientific Services, Kessels Road, Coopers Plains, QLD 4109 (Australia)]. E-mail: geoff_eaglesham@health.qld.gov.au

2007-05-15

112

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

International Nuclear Information System (INIS)

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 ?g L-1 or 232 ?g 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 ?g 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. - Cane toad tadpoles experienced adverse effects and bioaccumulation of toxin following exposure to the cyanobacterium Cylindrospermopsis raciborskii

113

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english 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 tu [...] bule 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.

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

2003-04-01

114

Molecular systematics, hybridization, and phylogeography of the Bufo americanus complex in Eastern North America.  

Science.gov (United States)

We reconstruct phylogenetic relationships among a well-studied group of toads and find relationships that differ greatly from the current taxonomic understanding. We use mitochondrial sequences encoding ND1, tRNA(Leu(UUR)), and part of 16S to infer relationships among members of the Bufo americanus complex. Focusing on the four taxa that historically have been most problematic due to morphological similarity and hybridization in sympatry, we sample 150 individuals from multiple populations across each species' geographic range. Our evidence conflicts with previous taxonomic hypotheses that were based on ability to hybridize, geographic distribution, and call variation. First, sequences from B. fowleri do not comprise the sister clade to sequences of B. woodhousii; therefore the previous classifications of B. fowleri as sister species to, or eastern subspecies of, B. woodhousii are both called into question. Second, sequences from B. americanus are more closely related to those of B. woodhousii than to those of B. terrestris, indicating that similar advertisement call characteristics evolved independently. Third, sequences of B. fowleri are paraphyletic, with sequences of B. terrestris embedded within. Lastly, sequences from B. fowleri cluster into three distinct mitochondrial clades, with some divergences corresponding to greater than 2mya. These clades are somewhat geographically structured, suggesting divergence in allopatry during the Pleistocene. These mitochondrial divergences are not accompanied by known phenotypic differences, however, suggesting either evolutionary stasis in morphology and behavior, cryptic phenotypic evolution, or that hybridization in secondary contact has homogenized phenotypic differences that may have arisen in allopatry. PMID:12144763

Masta, Susan E; Sullivan, Brian K; Lamb, Trip; Routman, Eric J

2002-08-01

115

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

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Alejandro Farías

2003-04-01

116

Study on Comparative Histology of Retinas in Ctenopharyngodon idella, Cynops orientalis, Bufo bufo gargarizans, Gekko japonicus, and Columba livia / Estudio Histológico Comparado de la Retina en Ctenopharyngodon Idella, Cynops Orientalis, Bufo Bufo Gargarizans, Gekko Japonicus, y Columba Livia  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish El objetivo de este estudio fue explorar la relación entre las estructuras de la retina y su adaptación al medioambiente en Ctenopharyngodon idella, Cynops orientalis, Bufo bufo gargarizans,Gekko japonicus y Columba livia . La medición del espesor de cada capa de la retina, la capa nuclear y su diám [...] etro en los cinco animales, mostró a través del análisis estadístico que las capas nucleares en todos ellos fueron 4, y sus estructuras se pueden dividir en 10 capas cuando se observan con el microscopio óptico. El espesor de la retina de Ctenopharyngodon idella fue 190,49 µm, de Cynops orientalis fue 173,07 µm, de Bufo bufo gargarizans fue 195,06 µm, de Gekko japonicus fue 224,32 µm y de Columba livia fue 174,10 µm. El número de capas nucleares internas de la retina de Bufo gargarizans, Gekko japonicus y Columba livia fue mayor que sus capas nucleares externas, mientras que las capas nucleares internas de Ctenopharyngodon idella y Cynops orientalis fueron menos que las capas nucleares externas. La capa de conos y bastones de la retina de Cynops orientalis fue más desarrollada, pero su capa de fibras nerviosas presentó una elevada degeneración, lo que muestra una gran fotosensibilidad, pero una sensibilidad visual baja. En Columba livia, la capa de fibras nerviosas de la retina estuvo muy desarrollada, y de esta manera, su visión. El grado de desarrollo de las diferentes estructuras y funciones de la retina de Ctenopharyngodon idella, Cynops orientalis, Bufo bufo gargarizans, Gekko japonicus y Columba livia está relacionada con sus características de comportamiento y el cambio de las condiciones de las vidas acuática y anfibia en la tierra. Abstract in english The objective of this study was to explore the relationship between the retinal structure and its life adaptation to the environment of Ctenopharyngodon idella, Cynops orientalis, Bufo bufo gargarizans, Gekko japonicus and Columba livia . Measuring retinal thickness of each layer, the nuclei layer, [...] and the diameter of each nuclear layer of the five animals, the statistical data analysis shows that: the nuclei layers of five animals are all 4, and their structures can be divided to 10 layers when observing with optical microscope. The retinal thickness of Ctenopharyngodon idella was 190.49 mm, Cynops orientalis was 173.07 µm, and the Bufo bufo gargarizans was 195.06 µm, Gekko japonicus was 224.32 µm and Columba livia was 174.10 µm. The number of retinal inner nuclear layers of Bufo bufo gargarizans and Gekko japonicus and Columba livia are more than their outer nuclear layers, on the contrary, retinal inner nuclear layers of Ctenopharyngodon idella and Cynops orientalis are less than their outer nuclear layers. The rod and cone layer of retina of Cynops orientalis were more advanced, but their nerve fiber layer (NFL) degraded highly, revealing a strong photosensitivity but a low visual sensitivity; to Columba livia , their NFL of retina are highly developed, so as their vision. The different structures and functions of the retina of Ctenopharyngodon idella, Cynops orientalis, Bufo bufo gargarizans, Gekko japonicus and Columba livia correspond with their behavioral characteristics and the living environment's change from aquatic to amphibious to land.

Qiusheng, She; Zhenqiang, An; Chengqiang, Xia; Yunfei, Kong; Enxiang, Chen.

2014-09-01

117

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

International Nuclear Information System (INIS)

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 ?g Cu/g dry mass. Aqueous concentrations of Cu as low as 10 ?g/L significantly reduced survival to the free-swimming stage and no larvae reached metamorphosis at concentrations above 15 ?g/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. -- Highlights: ? Southern toad, Anaxyrus terrestris, embryos and larvae are highly sensitive to Cu. ? Significant variation in survivorship exists among clutches and populations. ? Clutches with prior Cu exposure had the lowest survivorship. ? Body burdens in larvae were up to 27.5 ?g Cu/g dry mass. -- Capsule: Southern toad aquatic survival is significantly reduced at 15 ?g Cu/L with variation in survivorship across clutches and populations

118

Participation of nitric oxide in the nucleus isthmi in CO2-drive to breathing in toads  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The nucleus isthmi (NI) is a mesencephalic structure of the amphibian brain. It has been reported that NI plays an important role in integration of CO2 chemoreceptor information and glutamate is probably involved in this function. However, very little is known about the mechanisms involved. Recently [...] , it has been shown that nitric oxide synthase (NOS) is expressed in the brain of the frog. Thus the gas nitric oxide (NO) may be involved in different functions in the brain of amphibians and may act as a neurotransmitter or neuromodulator. We tested the hypothesis that NO plays a role in CO2-drive to breathing, specifically in the NI comparing pulmonary ventilation, breathing frequency and tidal volume, after microinjecting 100 nmol/0.5 µl of L-NAME (a nonselective NO synthase inhibitor) into the NI of toads (Bufo paracnemis) exposed to normocapnia and hypercapnia. Control animals received microinjections of vehicle of the same volume. Under normocapnia no significant changes were observed between control and L-NAME-treated toads. Hypercapnia caused a significant (P

L.H., Gargaglioni; L.G.S., Branco.

1399-14-01

119

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

Science.gov (United States)

Elastic energy is critical for amplifying muscle power during the propulsive phase of anuran jumping. In this study, we use toads (Bufo marinus) to address whether elastic recoil is also involved after take-off to help flex the limbs before landing. The potential for such spring-like behaviour stems from the unusually flexed configuration of a toad's hindlimbs in a relaxed state. Manual extension of the knee beyond approximately 90° leads to the rapid development of passive tension in the limb as underlying elastic tissues become stretched. We hypothesized that during take-off, the knee regularly extends beyond this, allowing passive recoil to help drive limb flexion in mid-air. To test this, we used high-speed video and electromyography to record hindlimb kinematics and electrical activity in a hindlimb extensor (semimembranosus) and flexor (iliofibularis). We predicted that hops in which the knees extended further during take-off would require less knee flexor recruitment during recovery. Knees extended beyond 90° in over 80% of hops, and longer hops involved greater degrees of knee extension during take-off and more intense semimembranosus activity. However, knee flexion velocities during recovery were maintained despite a significant decrease in iliofibularis intensity in longer hops, results consistent with elastic recoil playing a role. PMID:25030045

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

2014-07-01

120

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

Directory of Open Access Journals (Sweden)

Full Text Available Abstract 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 the luckiest parasites, because it has found an empty niche in Australia. It now flourishes in > 20 endemic and exotic frog species, but its consequences are yet to be fully understood.

Phalen David N

2010-06-01

 
 
 
 
121

Participation of nitric oxide in the nucleus isthmi in CO2-drive to breathing in toads  

Directory of Open Access Journals (Sweden)

Full Text Available The nucleus isthmi (NI is a mesencephalic structure of the amphibian brain. It has been reported that NI plays an important role in integration of CO2 chemoreceptor information and glutamate is probably involved in this function. However, very little is known about the mechanisms involved. Recently, it has been shown that nitric oxide synthase (NOS is expressed in the brain of the frog. Thus the gas nitric oxide (NO may be involved in different functions in the brain of amphibians and may act as a neurotransmitter or neuromodulator. We tested the hypothesis that NO plays a role in CO2-drive to breathing, specifically in the NI comparing pulmonary ventilation, breathing frequency and tidal volume, after microinjecting 100 nmol/0.5 µl of L-NAME (a nonselective NO synthase inhibitor into the NI of toads (Bufo paracnemis exposed to normocapnia and hypercapnia. Control animals received microinjections of vehicle of the same volume. Under normocapnia no significant changes were observed between control and L-NAME-treated toads. Hypercapnia caused a significant (P<0.01 increase in ventilation only after intracerebral microinjection of L-NAME. Exposure to hypercapnia caused a significant increase in breathing frequency both in control and L-NAME-treated toads (P<0.01 for the control group and P<0.001 for the L-NAME group. The tidal volume of the L-NAME group tended to be higher than in the control group under hypercapnia, but the increase was not statistically significant. The data indicate that NO in the NI has an inhibitory effect only when the respiratory drive is high (hypercapnia, probably acting on tidal volume. The observations reported in the present investigation, together with other studies on the presence of NOS in amphibians, indicate a considerable degree of phylogenetic conservation of the NO pathway amongst vertebrates.

Gargaglioni L.H.

1999-01-01

122

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

Directory of Open Access Journals (Sweden)

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

Haley BOWCOCK, Gregory P. BROWN, Richard SHINE

2013-12-01

123

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

Science.gov (United States)

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 ?g Cu/g dry mass. Aqueous concentrations of Cu as low as 10 ?g/L significantly reduced survival to the free-swimming stage and no larvae reached metamorphosis at concentrations above 15 ?g/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. PMID:23500050

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

2013-06-01

124

Chronic hypoxia and chronic hypercapnia differentially regulate an NMDA-sensitive component of the acute hypercapnic ventilatory response in the cane toad (Rhinella marina).  

Science.gov (United States)

This study addressed the hypotheses that exposure to chronic hypoxia (CH) and chronic hypercapnia (CHC) would modify the acute hypercapnic ventilatory response in the cane toad (Rhinella marina; formerly Bufo marinus or Chaunus marinus) and its regulation by NMDA-mediated processes. Cane toads were exposed to 10 days of CH (10% O(2)) or CHC (3.5% CO(2)) followed by acute in vivo hypercapnic breathing trials, conducted before and after an injection of the NMDA-receptor channel blocker, MK801 into the dorsal lymph sac. CH, CHC and MK801 did not alter ventilation under acute normoxic normocapnic conditions. CH blunted the increase in breathing frequency during acute hypercapnia while CHC had no effect. The effect of CH on breathing frequency was mediated by a decrease in the number of breaths per breathing episode. Neither CH nor CHC altered breath area (volume). MK801 augmented breathing frequency (via an increase in breaths per episode) and total ventilation during acute hypercapnia in control toads and toads exposed to CH; there was no effect of MK801 on the increase in breathing frequency or total ventilation, during acute hypercapnia in toads exposed to CHC. The results indicate that CH and CHC differentially alter breathing pattern. Furthermore, they indicate an absence of NMDA-mediated glutamatergic tone during normoxic normocapnia but that NMDA-mediated processes attenuate the increase in breathing frequency during acute hypercapnia under control conditions and following CH but not following CHC. Given that MK801 was administered systemically, the effects could be acting anywhere in the reflex pathway from CO(2)-sensing to respiratory motor output. PMID:21359567

McAneney, Jessica; Gheshmy, Afshan; Manga, Jasmin; Reid, Stephen G

2011-08-01

125

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

Scientific Electronic Library Online (English)

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

Ning, Wang; Rui, Jia; Jing J., Wang; Liu W., Nie.

2010-02-01

126

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

Directory of Open Access Journals (Sweden)

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

Ning Wang

2010-02-01

127

Ventilatory behaviors of the toad Bufo marinus revealed by coherence analysis Padrões respiratórios do anfíbio Bufo marinus revelados por análise de coerência  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Breathing in amphibians is a remarkably complex behavior consisting of irregular breaths that may be taken singly or in bouts that are used to deflate and inflate the lungs. The valves at the two outlets of the buccal cavity (nares and glottis) need to be finely controlled throughout the bout for the expression of these complex respiratory behaviors. In this study, we use a technique based on the calculation of the coherence spectra between respiratory variables (buccal pressure; narial airfl...

Coelho, F. C.; Baker, T. L.; Smatresk, N. J.

2003-01-01

128

Determinación de la frecuencia de micronúcleos en eritrocitos de Bufo arenarum que habitan ambientes urbanizados / Determination of micronuclei frequency in erythrocytes of Bufo arenarum inhabiting urbanized environments  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish Los anfibios son constituyentes integrales de ecosistemas naturales y agrícolas, y debido a su sensibilidad pueden ser utilizados como bioindicadores. La frecuencia de micronúcleos se emplea como un biomarcador que evalúa la respuesta a agentes genotóxicos. El objetivo del trabajo fue determinar y c [...] omparar la frecuencia de micronúcleos en eritrocitos de Bufo arenarum que habitan ambientes antrópicos de la ciudad de Río Cuarto. Se escogieron tres sitios modificados: un lago urbano Lago Villa Dálcar (33º06´S-64º22´W) y dos sitios de cultivo denominados Cultivo1 (33º05'S-64º26'W) y Cultivo 2 (33º05'S-64º25'W). Como control se escogió un área ubicada en las sierras de Comechingones, en el Campo Experimental Las Guindas (32º35'S- 64º42'W), pertenecientes a la UNRC. En cada sitio se recolectaron ocho individuos utilizando trampas de caída y relevamientos por encuentros visuales. A cada individuo se le extrajo sangre de la vena angularis inmediatamente después de la captura. Se realizaron dos extendidos por cada individuo, se dejaron secar al aire por 24 hs, luego se fijaron con metanol por 20 minutos y se colorearon con Giemsa al 5% durante 10 minutos. Posteriormente los frotis fueron analizados con microscopio (1000X) y se tomaron fotografías con cámara digital. La frecuencia de micronúcleos fue contabilizada para 4000 células por individuo. Se realizaron comparaciones utilizando el test de Kruskal-Wallis. Las frecuencias de micronúcleos encontradas son: Las Guindas: 0,17 ± 0,23; Cultivo1: 0,78 ± 0,28; Cultivo 2: 0,61 ± 0,45 y Villa Dálcar: 0,76 ± 0,47. Existen diferencias significativas entre el control y los demás sitios (p Abstract in english Amphibians are integral constituents of natural and agricultural ecosystems, and because of their sensitivity can be used as bioindicators. Micronuclei test is used as a biomarker for determining the response to genotoxic agents. The purpose of this study was to determine and compare the frequency o [...] f micronuclei in peripheral blood erythrocytes of Bufo arenarum toads that inhabiting anthropic environments for the city of Rio Cuarto. Organisms used in the MN test were collected from three sites modified: an urban lakeVilla Dalcar (33º06´S-64º22´W) and two cultivation sites called Crop 1 (33º05'S-64º26'W) and Crop 2 (33º05'S-64º25'W). As a control site, an area in the mountains of Comechingones, Las Guindas (32º35'S-64º42'W), belonging to the UNRC was sampled. At each site, eight individuals were collected using pitfall traps and by visual encounter surveys. To each individual is bled from the vein angularis immediately after capture. We performed two extended for each individual, air-dried for 24 hours, then fixed with methanol for 20 minutes and stained with 5% Giemsa for 10 minutes. Then the smears were analyzed with microscope (1000X) and took pictures with digital camera. For each individual the frequency of micronuclei for 4000 cells was recorded. Comparisons were made using the Kruskal-Wallis test. Micronuclei frequencies found are: Las Guindas: 0.17± 0.23; Crop 1: 0.78 ± 0.28, Crop 2: 0.61 ± 0.45 and Villa Dalcar: 0.76 ± 0.47. There are significant differences between the control and the other sites (p

Evangelina, Caraffa; Clarisa del L, Bionda; Favio E, Pollo; Nancy E, Salas; Adolfo L, Martino.

2013-12-01

129

Cuatro especies nuevas de anuros (Bufonidae: bufo e Hilydae: hyla) del norte de la Argentina  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Se realizó una revisión de las especies del género Bufo de las selvas de altura del noroeste argentino. Como resultado se describen dos nuevas especies del grupo veraguensis-typhonius, y se invalida la cita de Bufo quechua Gallardo, 1961 para el país. Mediante métodos radiológicos se confirma la relación de B. gnustae Gallardo, 1967 con el mismo grupo. Se describen dos especies nuevas del género Hyla, del norte de Argentina. A revision of mountain Forest species of Bufo, from t...

Carrizo, Gustavo R.

1992-01-01

130

Cane toads on cowpats: commercial livestock production facilitates toad invasion in tropical australia.  

Science.gov (United States)

Habitat disturbance and the spread of invasive organisms are major threats to biodiversity, but the interactions between these two factors remain poorly understood in many systems. Grazing activities may facilitate the spread of invasive cane toads (Rhinella marina) through tropical Australia by providing year-round access to otherwise-seasonal resources. We quantified the cane toad's use of cowpats (feces piles) in the field, and conducted experimental trials to assess the potential role of cowpats as sources of prey, water, and warmth for toads. Our field surveys show that cane toads are found on or near cowpats more often than expected by chance. Field-enclosure experiments show that cowpats facilitate toad feeding by providing access to dung beetles. Cowpats also offer moist surfaces that can reduce dehydration rates of toads and are warmer than other nearby substrates. Livestock grazing is the primary form of land use over vast areas of Australia, and pastoral activities may have contributed substantially to the cane toad's successful invasion of that continent. PMID:23145158

González-Bernal, Edna; Greenlees, Matthew; Brown, Gregory P; Shine, Richard

2012-01-01

131

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

Science.gov (United States)

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

132

Comparing and Contrasting with Frog and Toad  

Science.gov (United States)

In this lesson, students will learn how to compare and contrast the experiences of the familiar characters, Frog and Toad, by completing t-charts and writing a simple paragraph about the similarities and differences in the characters' experiences across stories.

Childs, Rebecca

2012-04-09

133

Toad poisoning in three dogs: case reports  

Directory of Open Access Journals (Sweden)

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

CM Barbosa

2009-01-01

134

Toad poisoning in three dogs: case reports  

Scientific Electronic Library Online (English)

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

CM, Barbosa; MS, Medeiros; CCM, Riani Costa; AC, Camplesi; M., Sakate.

135

Invasive cane toads: social facilitation depends upon an individual's personality.  

Science.gov (United States)

Individual variation in behavioural traits (including responses to social cues) may influence the success of invasive populations. We studied the relationship between sociality and personality in invasive cane toads (Rhinella marina) from a recently established population in tropical Australia. In our field experiments, we manipulated social cues (the presence of a feeding conspecific) near a food source. We captured and compared toads that only approached feeding sites where another toad was already present, with conspecifics that approached unoccupied feeding sites. Subsequent laboratory trials showed correlated personality differences (behavioural syndromes) between these two groups of toads. For example, toads that approached already-occupied rather than unoccupied feeding sites in the field, took longer to emerge from a shelter-site in standardized trials, suggesting these individuals are 'shy' (whereas toads that approached unoccupied feeding stations tended to be 'bold'). Manipulating hunger levels did not abolish this difference. In feeding trials, a bold toad typically outcompeted a shy toad under conditions of low prey availability, but the outcome was reversed when multiple prey items were present. Thus, both personality types may be favored under different circumstances. This invasive population of toads contains individuals that exhibit a range of personalities, hinting at the existence of a wide range of social dynamics in taxa traditionally considered to be asocial. PMID:25033047

González-Bernal, Edna; Brown, Gregory P; Shine, Richard

2014-01-01

136

Two-dimensional countercurrent chromatography × high performance liquid chromatography for preparative isolation of toad venom.  

Science.gov (United States)

In this work, a new on-line two-dimensional chromatography coupling of flow programming counter-current chromatography and high-performance liquid chromatography (2D CCC×HPLC) was developed for preparative separation of complicated natural products. The CCC column was used as the first dimensional isolation and a preparative ODS column operated in reversed-phase (RP) mode as the second dimension. The CCC was operated at a controlled flow rate to ensure that each fraction eluted within one hour, corresponding to the isolation time of the 2nd dimensional preparative HPLC. The eluent from the 1st dimensional CCC was diluted using a makeup pump and trapped onto holding column, before been eluted and transferred to the 2nd dimensional HPLC. The performance of the holding column was evaluated, in terms of column size, dilution ratio and diameter-height ratio, as well as system pressure, for the solution to the issue of online trapping of low pressure eluent from a CCC column. Satisfactory trapping efficiency and tolerable CCC pressure can be achieved using a commercially available 15mm×30mm i.d. ODS pre-column. The present integrated system was successfully applied in a one-step preparative separation of 12 compounds, from the crude methanol extract of venom of Bufo bufo gargarizans. Compounds 1-12 were isolated in overall yield of 1.0%, 0.8%, 2.0%, 1.3%, 2.0%, 1.5%, 1.9%, 3.6%, 6.1%, 4.8%, 3.5% and 4.1%, with HPLC purity of 99.9%, 99.7%, 90.6%, 99.9%, 77.0%, 99.9%, 90.4%, 99.9%, 52.0%, 99.9%, 99.3%, and 85.0%, respectively. All the results demonstrate that the flow programming CCC×HPLC method is an efficient and convenient way for the separation of compounds from toad venom and it can also be applied to isolate other complex multi-component natural products. PMID:24484689

Qiu, Ying-Kun; Yan, Xia; Fang, Mei-Juan; Chen, Lin; Wu, Zhen; Zhao, Yu-Fen

2014-02-28

137

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

DEFF Research Database (Denmark)

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). Hematological and cardio-respiratory 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, PO(2) and [HbO(2)]. 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 cardio-metabolic parameters. In conclusion, we found no evidence for temperature induced cardio-respiratory failure in Rhinella marina indicating that maintenance of aerobic scope and oxygen transport is unrelated to the upper thermal limit of this air-breathing semi-terrestrial vertebrate.

Overgaard, Johannes; Andersen, Jonas Lembcke

2012-01-01

138

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

Science.gov (United States)

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. PMID:22771750

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

2012-10-15

139

Cuatro especies nuevas de anuros (Bufonidae: Bufo e Hilydae: Hyla del norte de la Argentina  

Directory of Open Access Journals (Sweden)

Full Text Available Se realizó una revisión de las especies del género Bufo de las selvas de altura del noroeste argentino. Como resultado se describen dos nuevas especies del grupo veraguensis-typhonius, y se invalida la cita de Bufo quechua Gallardo, 1961 para el país. Mediante métodos radiológicos se confirma la relación de B. gnustae Gallardo, 1967 con el mismo grupo. Se describen dos especies nuevas del género Hyla, del norte de Argentina. A revision of mountain Forest species of Bufo, from the North-western Argentina was made. As a result, two new species from the veraguensis-typhonius group are described. The previous report of Bufo quechua Gallardo, 1961 for Argentina is invalidated. By means of radiology methods, the relationship between B. gnustae Gallardo, 1967 and ibis group is confirmed. Two new species of genus Hyla, from the northern Argentina are described.

Carrizo, Gustavo R.

1992-01-01

140

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

Directory of Open Access Journals (Sweden)

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

David Arome

2014-07-01

 
 
 
 
141

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

DEFF Research Database (Denmark)

The isolated toad (Bufo bufo) skin was mounted under voltage-clamp conditions in a chamber shown to cause no significant edge damage. The serosal side of the skin was bathed with NaCl-Ringer's, and the passive voltage-sensitive anion conductance studied in its fully voltage activated state, V = -80 mV (apical bath negative). The active sodium currents were eliminated by replacing external Na+ with K+. With [Cl-]o varying between 1.45 mM and 110 mM (gluconate substitution) and [I-]o = 3 mM, the total clamping current (y) and the sum of halide currents (x), estimated from flux measurements, were related by y = 1.0x-3.7 microA cm-2 (r2 = 0.98, n = 50 preparations). The increase in [Cl-]o produced a sigmoidal increase in Cl- influx and clamping current, with the rate coefficient for the influx increasing with [Cl-]o for 1.45 less than [Cl-]o less than 60 mM, but decreasing slightly again as [Cl-]o was further raised to 110 mM. A similar relationship was obtained between the rate coefficient for the Br- influx and[Br-]o, and the I- influx and [Cl-]o, indicating that these three ions are transported by a pathway that is activated by Cl-o and Br-o. The rate coefficients for the influxes ranked as follows, I-:Cl-:Br- = 0.7:1:1.3. The I-/Cl- selectivity was shown to be independent of the degree of Cl-o activation of the anion pathway, and identical with the I-/Cl- selectivity of a furosemide-sensitive, conductive pathway. With [Cl-]o, [Br-]o, or [I-]o = 110 mM, the currents ranked as follows, Cl-:Br-:I- = 1:0.68:0.06, indicating that Cl-, to a lesser extent Br-, and I-, poorly activate the conductive anion pathway. External I- was a potent inhibitor of the Cl-o activation of the Cl- conductance. The unidirectional I- fluxes ([I-]o = [I-]i = 3 mM, [Cl-]o = [Cl-]i = 110 mM) revealed passive transport for V less than -50 mV, active transport for V = o mV, and exchange diffusion for V = 50 mV, confirming our previous finding that depending on the transepithelial potential, the toad skin exhibits three modes of anion transport. A model that shares some properties with that of the anion transport system of the red cell membrane accounts for our findings, and for an inwardly directed active Cl- flux in terms of Cl-/HCO3- exchange.

Harck, A F; Larsen, Erik Hviid

1986-01-01

142

Responsiveness of the hypothalamo-pituitary-interrenal axis in an amphibian (Bufo terrestris) exposed to coal combustion wastes  

International Nuclear Information System (INIS)

To assess the responsiveness of the interrenal axis to stress, we injected toads exposed to coal combustion wastes and toads from an unpolluted reference site with adrenocorticotropic hormone (ACTH), as well as the vehicle alone (saline). Initial circulating levels of corticosterone in toads captured at the polluted area were significantly higher than levels in toads from the reference site. Corticosterone levels in toads from the polluted site remained high even after 2 weeks of laboratory acclimation and injection with saline. The results may suggest disruption of hepatic enzymes responsible for the metabolic clearance of steroid hormones. Injection of toads from the polluted site with ACTH had no effect on plasma corticosterone levels, whereas a similar treatment of toads from the reference site stimulated a marked increase in corticosterone. Our study provides evidence that toads exposed to coal combustion wastes may be less efficient at responding to additional environmental stressors. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

143

Responsiveness of the hypothalamo-pituitary-interrenal axis in an amphibian (Bufo terrestris) exposed to coal combustion wastes.  

Science.gov (United States)

To assess the responsiveness of the interrenal axis to stress, we injected toads exposed to coal combustion wastes and toads from an unpolluted reference site with adrenocorticotropic hormone (ACTH), as well as the vehicle alone (saline). Initial circulating levels of corticosterone in toads captured at the polluted area were significantly higher than levels in toads from the reference site. Corticosterone levels in toads from the polluted site remained high even after 2 weeks of laboratory acclimation and injection with saline. The results may suggest disruption of hepatic enzymes responsible for the metabolic clearance of steroid hormones. Injection of toads from the polluted site with ACTH had no effect on plasma corticosterone levels, whereas a similar treatment of toads from the reference site stimulated a marked increase in corticosterone. Our study provides evidence that toads exposed to coal combustion wastes may be less efficient at responding to additional environmental stressors. PMID:10190044

Hopkins, W A; Mendonça, M T; Congdon, J D

1999-02-01

144

Further Hopping with Toads and Frogs  

CERN Document Server

We show the value of positions of the combinatorial game ``Toads and Frogs''. We present new values of starting positions. Moreover, we discuss the values of all positions with exactly one $\\Box, \\regT^{a}\\Box\\Box \\regF^{a}, \\regT^{a} \\Box \\Box \\Box \\regF \\regF \\regF,\\regT^{a}\\Box\\Box \\regF^{b}$, $\\regT^{a}\\Box\\Box\\Box \\regF^{b}$. At the end, we post five new conjectures and discuss the possible future work.

Thanatipanonda, Thotsaporn ``Aek''

2008-01-01

145

Biogeographic patterns of Colombian frogs and toads  

International Nuclear Information System (INIS)

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

146

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

Directory of Open Access Journals (Sweden)

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

Ewa Krzysztofowicz

2011-08-01

147

Do invasive cane toads affect the parasite burdens of native Australian frogs??  

Science.gov (United States)

One of the most devastating impacts of an invasive species is the introduction of novel parasites or diseases to native fauna. Invasive cane toads (Rhinella marina) in Australia contain several types of parasites, raising concern that the toads may increase rates of parasitism in local anuran species. We sampled cane toads and sympatric native frogs (Limnodynastes peronii, Litoria latopalmata, and Litoria nasuta) at the southern invasion front of cane toads in north-eastern New South Wales (NSW). We dissected and swabbed these anurans to score the presence and abundance of nematodes (Rhabdias lungworms, and gastric encysting nematodes), myxozoans, and chytrid fungus. To determine if cane toad invasion influences rates of parasitism in native frogs, we compared the prevalence and intensity of parasites in frogs from areas with toads, to frogs from areas without toads. Contrary to the situation on the (rapidly-expanding) tropical invasion front, cane toads on the slowly-expanding southern front were heavily infected with rhabditoid lungworms. Toads also contained gastric-encysting nematodes, and one toad was infected by chytrid fungus, but we did not find myxozoans in any toads. All parasite groups were recorded in native frogs, but were less common in areas invaded by toads than in nearby yet to be invaded areas. Contrary to our predictions, toad invasion was associated with a reduced parasite burden in native frogs. Thus, cane toads do not appear to transfer novel parasites to native frog populations, or act as a reservoir for native parasites to ‘spill-back’ into native frogs. Instead, cane toads may reduce frog-parasite numbers by taking up native parasites that are then killed by the toad’s immune defences. PMID:24533330

Lettoof, Damian C.; Greenlees, Matthew J.; Stockwell, Michelle; Shine, Richard

2013-01-01

148

The early toad gets the worm: cane toads at an invasion front benefit from higher prey availability.  

Science.gov (United States)

In biological invasions, rates of range expansion tend to accelerate through time. What kind of benefits to more rapidly dispersing organisms might impose natural selection for faster rates of dispersal, and hence the evolution of range-edge acceleration? We can answer that question by comparing fitness-relevant ecological traits of individuals at the invasion front compared with conspecifics in the same area a few years post-invasion. In tropical Australia, the rate of invasion by cane toads (Rhinella marina) has increased substantially over recent decades, due to shifts in heritable traits. Our data on field-collected cane toads at a recently invaded site in the Australian wet-dry tropics span a 5-year period beginning with toad arrival. Compared with conspecifics that we monitored in the same sites post-invasion, toads in the invasion vanguard exhibited higher feeding rates, larger energy stores, better body condition and faster growth. Three processes may have contributed to this pattern: (i) higher prey availability at the front (perhaps due to reduced competition from conspecifics); (ii) the lack of viability-reducing parasites and pathogens in invasion-front toads; and (iii) distinctive (active, fast-growing) phenotypes of the invasion-front toads. Nutritional benefits to individuals in the invasion vanguard (whether because of higher prey availability, or lower pathogen levels) thus may have conferred a selective advantage to accelerated dispersal in this system. PMID:23360501

Brown, Gregory P; Kelehear, Crystal; Shine, Richard

2013-07-01

149

Do invasive cane toads affect the parasite burdens of native Australian frogs?  

Science.gov (United States)

One of the most devastating impacts of an invasive species is the introduction of novel parasites or diseases to native fauna. Invasive cane toads (Rhinella marina) in Australia contain several types of parasites, raising concern that the toads may increase rates of parasitism in local anuran species. We sampled cane toads and sympatric native frogs (Limnodynastes peronii, Litoria latopalmata, and Litoria nasuta) at the southern invasion front of cane toads in north-eastern New South Wales (NSW). We dissected and swabbed these anurans to score the presence and abundance of nematodes (Rhabdias lungworms, and gastric encysting nematodes), myxozoans, and chytrid fungus. To determine if cane toad invasion influences rates of parasitism in native frogs, we compared the prevalence and intensity of parasites in frogs from areas with toads, to frogs from areas without toads. Contrary to the situation on the (rapidly-expanding) tropical invasion front, cane toads on the slowly-expanding southern front were heavily infected with rhabditoid lungworms. Toads also contained gastric-encysting nematodes, and one toad was infected by chytrid fungus, but we did not find myxozoans in any toads. All parasite groups were recorded in native frogs, but were less common in areas invaded by toads than in nearby yet to be invaded areas. Contrary to our predictions, toad invasion was associated with a reduced parasite burden in native frogs. Thus, cane toads do not appear to transfer novel parasites to native frog populations, or act as a reservoir for native parasites to 'spill-back' into native frogs. Instead, cane toads may reduce frog-parasite numbers by taking up native parasites that are then killed by the toad's immune defences. PMID:24533330

Lettoof, Damian C; Greenlees, Matthew J; Stockwell, Michelle; Shine, Richard

2013-12-01

150

The envelopes of amphibian oocytes: physiological modifications in Bufo arenarum  

Directory of Open Access Journals (Sweden)

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

Sánchez Mercedes

2003-02-01

151

Lankesterella poeppigii n. sp. (Apicomplexa, Lankesterellidae) from Bufo poeppigii (Tschudi, 1845) from Peru / Lankesterella poeppigii n. sp. (Apicomplexa, Lankesterellidae) de Bufo poeppigii (Tschudi, 1845) del Perú  

Scientific Electronic Library Online (English)

Full Text Available SciELO Peru | Language: English Abstract in spanish Lankesterella poeppigii n. sp. es descrita de Bufo poeppigii (Tschudi, 1845) del Perú. La merogonia y oogonia se producen en el endotelio capilar y los macrófagos en el hígado, el bazo y los riñones. Los esquizontes son ovalados, 25,2-29,4 x 15,7-16,8 micras de tamaño y producen 35-46 merozoitos. Lo [...] s ooquistes miden 26,3-29,4 x 15,1-17,6 micras de tamaño; esporozoitos, reunidos en los macrófagos, miden 9,2-9,8 x 4,2-5,0 micras de tamaño. Liberados, los esporozoitos miden 8,7-9,8 x 2,8-3,1 micras y entran en los eritrocitos. Lankesterella poeppigii es comparada con L. petiti Lainson y Paperna, 1995, que infecta a Bufo marinus (Linnaeus, 1758) en Brasil. Los caracteres específicos citados, sumados a las diferencias entre los huespédes y en la localización geográfica justifican la clasificación de la Lankesterella de B. poeppigii como una nueva especie. Abstract in english Lankesterella poeppigii n. sp. is described from Bufo poeppigii (Tschudi, 1845) from Peru. Merogony and oogony occur in the capillary endothelium and the macrophages in the liver, spleen and kidneys. Meronts are oval, 25,2-29,4 x 15,7-16,8 µm in size and yield 35-46 merozoites. Oocysts are 26,3-29,4 [...] x 15,1-17,6 µm in size; sporozoites 9,2-9,8 x 4,2-5,0 µm in size, assemble in macrophages. Released 8,7-9,8 x 2,8-3,1 µm sporozoites enter erythrocytes. L. poeppigii is compared with Lankesterella petiti Lainson & Paperna, 1995 infecting Bufo marinus (Linnaeus, 1758) in Brazil. The above mentioned specific characters, added to differences in hosts and geographical location warrant the description of Lankesterella poeppigii from B. poeppigii as a new species.

Ilan, Paperna; Patrick, Bastien; Jean-Marc, Chavatte; Irène, Landau.

2009-12-01

152

Phosphorus-31 nuclear magnetic resonance spectroscopy of toad retina.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Phosphorus-31 nuclear magnetic resonance (31P-NMR) spectra were obtained from living toad retinae and toad retinal extracts at 4 degrees C. Several phosphorus metabolites--nucleoside di- and triphosphates (NTP), phosphocreatine, phosphodiesters, inorganic phosphate, and phosphomonoesters--were identified from the spectra of whole retinae. The intracellular pH was determined to be 7.27 +/- 0.06 at 4 degrees C and the intracellular MgNTP/NTP ratio was at least 0.77. These results are consistent...

Apte, D. V.; Koutalos, Y.; Mcfarlane, D. K.; Dawson, M. J.; Ebrey, T. G.

1989-01-01

153

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

Science.gov (United States)

Temperature has a strong influence on biological rates, including the contractile rate properties of muscle and thereby the velocity, acceleration and power of muscle-powered movements. We hypothesized that the dynamics of movements powered by elastic recoil have a lower thermal dependence than muscle-powered movements. We examined the prey capture behavior of toads (Bufo terrestris) using high speed imaging and electromyography to compare the effects of body temperature (11-35°C) on the kinematics, dynamics and motor control of two types of movement: (1) ballistic mouth opening and tongue projection, which are powered by elastic recoil, and (2) non-ballistic prey transport, including tongue retraction and mouth closing, which are powered directly by muscle contraction. Over 11-25°C, temperature coefficients of ballistic mouth opening and tongue projection dynamics (Q(10) of 0.99-1.25) were not significantly different from 1.00 and were consistently lower than those of prey transport movements (Q(10) of 1.77-2.26), supporting our main hypothesis. The depressor mandibulae muscle, which is responsible for ballistic mouth opening and tongue projection via the recovery of elastic strain energy stored by the muscle prior to the onset of the movement, was activated earlier and for a longer duration at lower temperatures (Q(10) of 2.29-2.41), consistent with a slowing of its contractile rates. Muscle recruitment was unaffected by temperature, as revealed by the lack of thermal dependence in the intensity of activity of both the jaw depressor and jaw levator muscles (Q(10) of 0.754-1.12). Over the 20-35°C range, lower thermal dependence was found for the dynamics of non-elastic movements and the motor control of both elastic and non-elastic movements, in accord with a plateau of high performance found in other systems. PMID:21430211

Deban, Stephen M; Lappin, A Kristopher

2011-04-15

154

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

Science.gov (United States)

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.

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

155

Antibacterial activity of lactose-binding lectins from Bufo arenarum skin  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english 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 b-galactoside-binding lectins with molecular weights of 50 and 56 KDa from the s [...] kin 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 mmolar 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.

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

2003-04-01

156

Antibacterial activity of lactose-binding lectins from Bufo arenarum skin  

Directory of Open Access Journals (Sweden)

Full Text Available 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 b-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 mmolar 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.

Alicia Sánchez Riera

2003-04-01

157

An introduced pentastomid parasite (Raillietiella frenata) infects native cane toads (Rhinella marina) in Panama.  

Science.gov (United States)

SUMMARY The pentastomid parasite, Raillietiella frenata, is native to Asia where it infects the Asian House gecko, Hemidactylus frenatus. This gecko has been widely introduced and recently R. frenata was found in introduced populations of cane toads (Rhinella marina) in Australia, indicating a host-switch from introduced geckos to toads. Here we report non-native adult R. frenata infecting the lungs of native cane toads in Panama. Eight of 64 toads were infected (median = 2·5, range = 1-80 pentastomids/toad) and pentastomid prevalence was positively associated with the number of buildings at a site, though further sampling is needed to confirm this pattern. We postulate that this pattern is likely due to a host shift of this parasite from an urban-associated introduced gecko. This is the first record of this parasite infecting cane toads in their native range, and the first instance of this parasite occurring in Central America. PMID:25394910

Kelehear, Crystal; Saltonstall, Kristin; Torchin, Mark E

2014-11-14

158

B-carotene Lock the Effect of Acrylamide on Liver in the Egyptian Toad  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several studies on the harmful effects of chemical pollutants have had an increasing influence on public cancer policy. It has been shown that acrylamide, which is widely used in the synthesis of variety of polymers, induced liver tumor in the Egyptian toad (9 cases out of 50 cases). The liver tumor was diagnosed as hepatocellular carcinoma. In contrast toads treated with acrylamide and B-carotene (3 hr. prior to the carcinogen) completely blocked the hepatocarcinogenesis in toads. However B-...

Sadek, I. A.; Abou-gabal, A.

1999-01-01

159

Invasive Cane Toads: Social Facilitation Depends upon an Individual’s Personality  

Science.gov (United States)

Individual variation in behavioural traits (including responses to social cues) may influence the success of invasive populations. We studied the relationship between sociality and personality in invasive cane toads (Rhinella marina) from a recently established population in tropical Australia. In our field experiments, we manipulated social cues (the presence of a feeding conspecific) near a food source. We captured and compared toads that only approached feeding sites where another toad was already present, with conspecifics that approached unoccupied feeding sites. Subsequent laboratory trials showed correlated personality differences (behavioural syndromes) between these two groups of toads. For example, toads that approached already-occupied rather than unoccupied feeding sites in the field, took longer to emerge from a shelter-site in standardized trials, suggesting these individuals are ‘shy’ (whereas toads that approached unoccupied feeding stations tended to be ‘bold’). Manipulating hunger levels did not abolish this difference. In feeding trials, a bold toad typically outcompeted a shy toad under conditions of low prey availability, but the outcome was reversed when multiple prey items were present. Thus, both personality types may be favored under different circumstances. This invasive population of toads contains individuals that exhibit a range of personalities, hinting at the existence of a wide range of social dynamics in taxa traditionally considered to be asocial. PMID:25033047

González-Bernal, Edna; Brown, Gregory P.; Shine, Richard

2014-01-01

160

Travelling waves for the cane toads equation with bounded traits  

Science.gov (United States)

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

Bouin, Emeric; Calvez, Vincent

2014-09-01

 
 
 
 
161

Comparative effects of mast cell degranulators on perfused systemic blood vessels of Bufo melanostictus and Rana tigrina.  

Science.gov (United States)

Three agents known to induce release of mast cell constituents, viz. polymyxin, compound 48/80 and polysorbate-80, were evaluated for effect on perfused blood vessels of R. tigrina and B. melanostictus. The mast cell degranulators caused vasoconstriction in frog and toad, except that for P-80 whose responses in toad were equivocal. Toads showed a general low responsiveness in comparison to frogs. Pharmacologic intervention with pheniramine, metergoline, hydergine, atropine and mecamylamine, respectively ruled out role of histamine, 5-HT, catecholamine or acetylcholine or even autonomic mechanisms in the above phenomena. The observations are suggestive of phylogenetic differences in biochemical profile of mast cells in amphibian species. PMID:1338198

Singh, R K; Gambhir, S S

1992-12-01

162

Effects of ultraviolet radiation on boreal toads in Colorado  

Science.gov (United States)

Field exposures of Bufo boreas embryos to fractions of ambient UV-B radiation at two sites in Rocky Mountain National Park, Colorado, USA, were conducted to evaluate UV-B as a possible cause of recent severe declines of this species. There were no differences in hatching success of B. boreas embryos exposed to 0-100% of ambient UV-B radiation at either study site, results that are different from those of recent studies in Oregon that found increased mortality of B. boreas embryos exposed to ambient UV-B. The reasons for these differing results are not apparent, and several possible explanations exist, including differences in experimental design, presence or absence of a pathogenic fungus, and geographic genetic variation. Bufo boreas embryos were probably not receiving higher doses of UV-B radiation during the experiments in Oregon compared to the experiments in this study. Results of this study do not support UV-B radiation alone as the cause of the decline of B. boreas during the past 20 yr in the southern Rocky Mountains, but UV-B cannot be dismissed because of the contradictory results from other studies.

Corn, P.S.

1998-01-01

163

Interacting impacts of invasive plants and invasive toads on native lizards.  

Science.gov (United States)

The ecological impacts of an invasive species may be reduced by prior invasions if selective pressures imposed by earlier events preadapt the native biota to deal with the newer arrival. In northwestern Australia, invasion of the cane toad (Rhinella marina) kills many native predators if they ingest the highly toxic toads. Remarkably, the toads' defensive toxins (bufadienolides) are chemically similar to those of another invasive species: an ornamental plant from Madagascar, Bryophyllum spp. (Crassulaceae, mother-of-millions). Omnivorous lizards (bluetongue skinks, Tiliqua scincoides) are imperiled by the invasion of toads in northwestern Australia, but conspecifics from other areas of the continent (those where exotic plants were introduced and including areas where toads have yet to invade) are less affected because they exhibit higher physiological tolerance of toad toxins (and also of plant toxins). The willingness of captive bluetongues to consume both toads and these plants and the high correlation in the lizards' sensitivity to toad toxins versus plant toxins suggest that exotic plants may have imposed strong selection on the lizards' physiological tolerance of bufadienolides. As a result, populations of lizards from areas previously exposed to these alien plants may be preadapted to deal with the toxins of the more recent anuran invader. PMID:22322228

Price-Rees, Samantha J; Brown, Gregory P; Shine, Richard

2012-03-01

164

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

Science.gov (United States)

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

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

2012-09-01

165

CAS role in the brain apoptosis of Bufo arenarum induced by Cypermethrin  

Directory of Open Access Journals (Sweden)

Full Text Available 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 µg 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 ?-catenin, in contrast of ?-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.

M. F. Izaguirre

2006-08-01

166

CAS role in the brain apoptosis of Bufo arenarum induced by Cypermethrin  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english 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 µg 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 ?-catenin, in contrast of ?-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.

M. F., Izaguirre; M. N., Vergara; V. H., Casco.

2006-08-01

167

Descripción de dos renacuajos y una clave para las larvas conocidas del grupo Bufo spinulosus (Anura: Bufonidae) de Perú / Description of two tadpoles and a key to the known larvae of the Bufo spinulosus group (Anura: Bufonidae) occurring in Peru  

Scientific Electronic Library Online (English)

Full Text Available SciELO Peru | Language: Spanish Abstract in spanish Se describen los renacuajos de Bufo arequipensis y Bufo cophotis. Ningún carácter externo examinado permite distinguir la larva de las especies nominales B. arequipensis, B. flavolineatus y B. trifolium. La larva de Bufo limensis se diferencia de las de B. flavolineatus y B. trifolium por presentar [...] un espacio menor en la segunda fila anterior de dentículos labiales y una fórmula de dentículos labiales (LTRF) igual a 2(2)/3[1]. B. cophotis difiere de B. limensis, B. flavolineatus y B. trifolium por presentar la altura máxima de la cola en su extremo posterior, una coloración marrón oscura en el cuerpo y cola, y un LTRF igual a 2(2)/3(1). Se proporciona una clave de identificación para las larvas conocidas del grupo spinulosus presentes en Perú. Abstract in english The tadpoles of Bufo arequipensis and Bufo cophotis are described. No external larval character studied allowed the distinction between the tadpoles of the nominal species B. arequipensis, B. flavolineatus and B. trifolium. The tadpole of B. limensis differs from the ones of B. flavolineatus and B. [...] trifolium by the presence of a small gap in the second anterior tooth row and a 2(2)/3[1] labial tooth row formula (LTRF). The tadpole of B. cophotis differs from B. limensis, B. flavolineatus and B. trifolium larvae by showing the highest part of the tail in its posterior end, a dark brown coloration in the body and tail, and a 2(2)/3(1) LTRF. An identification key for the known Peruvian tadpoles of the spinulosus group is provided.

César, Aguilar; Rocío, Gamarra.

2004-07-01

168

2.MD Frog and Toad on the number line  

Science.gov (United States)

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: One day, Frog and Toad were sitting together on a lily pad. Some lily pads were in a line across the pond. In the morning, Frog hopped three lily pads ...

169

Glyoxylate cycle in toad urinary bladder: possible stimulation by aldosterone.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A homogenate of the toad urinary bladder epithelial cell layer has the two enzymatic activities unique to the glyoxylate cycle--isocitrate lyase (threo-Ds-isocitrate glyoxylate-lyase, EC 4.1.3.1) and malate synthase [L-malate glyoxylate-lyase (CA-acetylating), EC 4.1.3.2]--as well as the capacity to carry out CN-insensitive palmitoyl-CoA oxidation. When tissue is incubated in the presence of a fatty acid substrate, tissue glycogen levels increase. Additionally, in the presence of aldosterone,...

Goodman, D. B.; Davis, W. L.; Jones, R. G.

1980-01-01

170

Toads as reservoirs of salmonellae: prevalence and antibiogram.  

Science.gov (United States)

Of 570 intestinal-content-samples of toads examined, 40 yielded salmonellae, which included 26 strains of S. goverdhan, 9 of S. bareilly, 2 of S. richmond, and 1 each of S. typhimurium, S. weltevreden and S. newport. From 52 visceral-organ samples, 6 strains of S. goverdhan and 1 of S. typhimurium were isolated. Antibiotic sensitivity studied against 18 chemotherapeutic agents, revealed that although the isolates were sensitive to most of the antibiotics, all of them were resistant to bacitracin, novobiocin and oleandomycin. To sulfonamides, erythromycin and pencillin, respectively, 42, 8 and 3 isolates were resistant. PMID:536124

Singh, S; Sharma, V D; Sethi, M S

1979-12-01

171

Reproductive strategies of leopard toad and mascarene frog from Giza, Egypt.  

Science.gov (United States)

I examined the reproductive strategies of leopard toad and mascarene frog by studying their annual vitellogenic cycle, monthly changes of masses of ovary, liver and fat bodies as well as egg size and number in two study areas, Abo Roash and El Mansuriya, and in the years 2001, 2005, and 2008-2009, particularly during the final two years of that period. Based on the presence of the mature ova, I found that vitellogenic cycle is continuous in toad, but discontinuous in frog. Further, leopard body reserves allocated more energy to vitellogenesis than did mascarene frog. Hence, fecundity in toad was higher than that in frog, as associated with higher egg number and size. During oviposition, female mascarene retained a small portion of a clutch, whereas toad shed all egg mass at once. Over the study period, both body and reproductive conditions reacted positively in toad, but negatively in frog. Warm temperature and long photoperiod elucidated ovarian development under high relative humidity in frog. In contrast, in toad, low relative humidity may be an environmental cue for the increase in ovarian mass. Thus, higher sexual activities occurred in spring for toad (dry environment), but in moist summer for frog. Ovarian mass and egg number were temperature-dependent in frog, but independent in toad. Relative humidity correlated significantly and negatively to egg size in both populations. It also related inversely to egg number in toad, but not in frog. Hence, eggs of the frog are controlled by both temperature and humidity in summer season. Rainfall had no effect on sexual parameters in both species. PMID:24410494

Akef, Mamdouh S A

2014-01-01

172

The antiepileptic drug phenytoin affects sodium transport in toad epithelium.  

Science.gov (United States)

The effects of phenytoin on isolated Pleurodema thaul toad skin were investigated. Low (micromolar) concentrations of the antiepileptic agent applied to the outside surface of the toad epithelium increased the electrical parameters (short-circuit current and potential difference) by over 40%, reflecting stimulation of Na(+) transport, whereas higher (millimolar concentrations, outside and inside surface) decreased both electric parameters, the effect being greater at the inside surface (40% and 80% decrease, respectively). The amiloride test showed that the stimulatory effect was accompanied by an increase and the inhibitory effect by a decrease in the sodium electromotive force (ENa). It is concluded that the drug interaction with membrane lipid bilayers might result in a distortion of the lipid-protein interface contributing to disturbance of Na(+) epithelial channel activity. After applying the Na(+)-K(+)-ATPase blocker ouabain and replacing the Na(+) ions in the outer Ringer's solution by choline, it was concluded that both active and passive transport are involved in sodium absorption, although active transport predominates. PMID:16314149

Suwalsky, Mario; Mennickent, Sigrid; Norris, Beryl; Cárdenas, Hernan

2006-01-01

173

B-carotene Lock the Effect of Acrylamide on Liver in the Egyptian Toad  

Directory of Open Access Journals (Sweden)

Full Text Available Several studies on the harmful effects of chemical pollutants have had an increasing influence on public cancer policy. It has been shown that acrylamide, which is widely used in the synthesis of variety of polymers, induced liver tumor in the Egyptian toad (9 cases out of 50 cases. The liver tumor was diagnosed as hepatocellular carcinoma. In contrast toads treated with acrylamide and B-carotene (3 hr. prior to the carcinogen completely blocked the hepatocarcinogenesis in toads. However B-carotene was less effective when administered 3hr, after the carcinogen (acrylamide in 7 out of 50 cases. It is concluded that B-carotene has an inhibitory effect on hepatocarcinogenesis in toads during initiation.

I. A. Sadek

1999-01-01

174

Invader immunology: invasion history alters immune system function in cane toads (Rhinella marina) in tropical Australia.  

Science.gov (United States)

Because an individual's investment into the immune system may modify its dispersal rate, immune function may evolve rapidly in an invader. We collected cane toads (Rhinella marina) from sites spanning their 75-year invasion history in Australia, bred them, and raised their progeny in standard conditions. Evolved shifts in immune function should manifest as differences in immune responses among the progeny of parents collected in different locations. Parental location did not affect the offspring's cell-mediated immune response or stress response, but blood from the offspring of invasion-front toads had more neutrophils, and was more effective at phagocytosis and killing bacteria. These latter measures of immune function are negatively correlated with rate of dispersal in free-ranging toads. Our results suggest that the invasion of tropical Australia by cane toads has resulted in rapid genetically based compensatory shifts in the aspects of immune responses that are most compromised by the rigours of long-distance dispersal. PMID:25399668

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

2015-01-01

175

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

Science.gov (United States)

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. PMID:21756910

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

2011-09-01

176

The All Optical New Universal Gate Using TOAD  

Directory of Open Access Journals (Sweden)

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

Goutam Kumar Maity

2014-06-01

177

Acclimation to Low Level Exposure of Copper in Bufo arenarum Embryos: Linkage of Effects to Tissue Residues  

Science.gov (United States)

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 ?g.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

Herkovits, Jorge; Pérez-Coll, Cristina Silvia

2007-01-01

178

Acclimation to Low Level Exposure of Copper in Bufo arenarum Embryos: Linkage of Effects to Tissue Residues  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Cristina Silvia Pérez-Coll

2007-06-01

179

The uptake of 14C-glycine to Bufo vulgaris formosus (Boulenger) larva at metamorphosis  

International Nuclear Information System (INIS)

With the eggs of Bufo vulgaris formosus (Boulenger) immediately after fertilization, the larvae in the 50 ml solution containing 1 ml of 14C-glycine were developed to the end of metamorphosis. Measurements were made on the length of body, tail, fore limb and hind leg through the stages of tail degeneration and vestige. The radioactivity of the cut off fore limbs, hind legs, tails and head trunks was measured with a scintillation counter, and the 10 ? sections of the samples were used for autoradiography. The larvae uptook orally 14C-glycine to the organs of cell tissues. On the basis of the reports of the autolysis of tails and the activation of lysosome enzyme in metamorphosis and on the uptake of 14C-leucine and 14C-proline to four legs by other workers, and on the present results, the free amino acids formed from the autolysis of tails were utilized for the recomposition of organ protein synthesis in the metamorphosis of the amphibians. (J.P.N.)

180

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

Directory of Open Access Journals (Sweden)

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

O. Fridman

2006-03-01

 
 
 
 
181

Characterisation of major histocompatibility complex class I in the Australian cane toad, Rhinella marina.  

Science.gov (United States)

The Major Histocompatibility Complex (MHC) class I is a highly variable gene family that encodes cell-surface receptors vital for recognition of intracellular pathogens and initiation of immune responses. The MHC class I has yet to be characterised in bufonid toads (Order: Anura; Suborder: Neobatrachia; Family: Bufonidae), a large and diverse family of anurans. Here we describe the characterisation of a classical MHC class I gene in the Australian cane toad, Rhinella marina. From 25 individuals sampled from the Australian population, we found only 3 alleles at this classical class I locus. We also found large number of class I alpha 1 alleles, implying an expansion of class I loci in this species. The low classical class I genetic diversity is likely the result of repeated bottleneck events, which arose as a result of the cane toad's complex history of introductions as a biocontrol agent and its subsequent invasion across Australia. PMID:25093458

Lillie, Mette; Shine, Richard; Belov, Katherine

2014-01-01

182

Embryonic exposure to conspecific chemicals suppresses cane toad growth and survival.  

Science.gov (United States)

Adaptations to suppress the viability of conspecifics may provide novel ways to control invasive taxa. The spread of cane toads (Rhinella marina) through tropical Australia has had severe ecological impacts, stimulating a search for biocontrol. Our experiments show that cane toad tadpoles produce waterborne chemical cues that suppress the viability of conspecifics encountering those cues during embryonic development. Brief (72 h) exposure to these cues in the egg and post-hatching phases massively reduced rates of survival and growth of larvae. Body sizes at metamorphosis (about three weeks later) were almost twice as great in control larvae as in tadpole-exposed larvae. The waterborne cue responsible for these effects might provide a weapon to reduce toad recruitment within the species' invaded range. PMID:21880623

Crossland, Michael R; Shine, Richard

2012-04-23

183

The antiepileptic drug carbamazepine affects sodium transport in toad epithelium.  

Science.gov (United States)

The present work investigates the effects of the antiepileptic drug carbamazepine (CBZ) on sodium transport in the isolated skin of the toad Pleurodema thaul. A submaximal concentration of the drug (0.2 mM) applied to the outer surface of the epithelium increased the electrical parameters short-circuit current (Isc) and potential difference (PD) by over 28%, whereas only a higher concentration (1 mM) induced over a 45% decrease in these parameters when applied to the inner surface. The amiloride test showed that the outer surface stimulatory effect was accompanied by an increase and the inner surface inhibitory effect by a decrease in the sodium electromotive force (ENa). Exploration of these effects of CBZ on the outer surface showed that 0.2 mM increased net Na+ (22Na) influx by 20% and 0.6 mM CBZ decreased Na+ mucosa-serosa flux by 19%, a result in agreement with the finding that higher concentrations of CBZ applied to the inner surface not only decreased ENa but also sodium conductance (GNa). PMID:16542818

Suwalsky, Mario; Mennickent, Sigrid; Norris, Beryl; Cardenas, Hernán

2006-09-01

184

Immunofluorescent localization of cyclic AMP in toad urinary bladder: possible intercellular transfer.  

Science.gov (United States)

By use of an immunofluorescent cytochemical staining technique, adenosine 3',5'-monophosphate (cyclic AMP) has been localized in toad bladder epithelial cells. Within 2 minutes after addition of vasopressin, staining intensity increases in both mitochondria-rich and granular cells. This finding, taken together with the precise anatomical relation between these two epithelial cell types and the observation that after separation of the two cell types vasopressin stimulates cyclic AMP accumulation in only mitochondria-rich cells, suggests that cyclic AMP may be transferred from mitochrondria-rich to granular cells as part of the response of the toad urinary bladder to vasopressin. PMID:167437

Goodman, D B; Bloom, F E; Battenberg, E R; Rasmussen, H; Davis, W L

1975-06-01

185

El ciclo evolutivo experimental de Diphyllobothrium erinaceieuropei en Paracyclops fimbriatus, larvas de Bufo arenarum y caninos Experimental life cycle of Diphyllobothrium erinaceieuropei in Paracyclops fimbriatus, tadpoles of Bufo arenarum and dogs  

Directory of Open Access Journals (Sweden)

Full Text Available El objetivo del trabajo fue lograr la reproducción experimental del ciclo evolutivo de Diphyllobothrium erinaceieuropei Rudolphi 1819 (Cestoda, Pseudophyllidea con la intervención de Paracyclops fimbriatus y larvas de Bufo arenarum como hospedadores intermediarios y caninos como hospedadores definitivos. Los huevos del parásito se obtuvieron de heces de caninos infectados naturalmente y se conservaron refrigerados en agua. Se incubaron 7 días a 25°C para que desarrollaran los coracidios y se pusieron en recipientes que contenían a los copépodos mencionados. Al cabo de 12 días a 22,6°C (promedio se hallaron procercoides maduros en ellos y se agregaron 10 renacuajos de Bufo arenarum. Estos se examinaron por disección 22, 23, 61 y 107 días después, hallándose en todos 1 o más plerocercoides (Temperatura promedio: 24,9°C. El día 23, de 6 renacuajos se obtuvieron 49 plerocercoides, de los cuales se administraron 28, por vía oral, a una perra. El día 107, 3 de 11 plerocercoides obtenidos de un renacuajo se le dieron a otra perra por la misma vía. Se hallaron huevos del cestode en las heces del primer canino a partir del día 22 posterior a la infección (p.i. y a los 30 días p.i., segmentos de estróbila. En el segundo canino se hallaron huevos a los 30 días p.i..Experiments were performed in order to develop the life cycle of Diphyllobothrium erinaceieuropei Rudolphi 1819 (Cestoda, Pseudophyllidea in Paracyclops fimbriatus and Bufo arenarum as intermediate hosts and dogs as definitive hosts. The eggs of Diphyllobothrium erinaceieuropei from faeces of naturally infected dogs were kept refrigered, in water. In order to obtain coracidiums they were incubated at 25°C, and then were placed in a flask which contained Paracyclops fimbriatus. The copepods were observed to be infected with procercoids 12 days after, (mean temperature 22.6°C and then, ten tadpoles of Bufo arenarum were put into the same flask. The tadpoles were examined 22, 23, 61 and 107 days later, finding plerocercoids in all them (mean temperature 24.9°C. On the 23th day, 49 plerocercoids were removed from 6 tadpoles and 28 of them were fed to a bitch. On the 107th day, 11 plerocercoids were recovered from a dead tadpole and 3 of them were fed to another bitch. In the faeces of the first bitch there were observed the eggs of Diphyllobothrium erinaceieuropei 22 days post infection (d.p.i. and part of the strobila 30 d.p.i.. In the faeces of the second bitch the eggs were found 30 d.p.i..

Lucila Venturini

1989-10-01

186

El ciclo evolutivo experimental de Diphyllobothrium erinaceieuropei en Paracyclops fimbriatus, larvas de Bufo arenarum y caninos / Experimental life cycle of Diphyllobothrium erinaceieuropei in Paracyclops fimbriatus, tadpoles of Bufo arenarum and dogs  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Spanish Abstract in spanish El objetivo del trabajo fue lograr la reproducción experimental del ciclo evolutivo de Diphyllobothrium erinaceieuropei Rudolphi 1819 (Cestoda, Pseudophyllidea) con la intervención de Paracyclops fimbriatus y larvas de Bufo arenarum como hospedadores intermediarios y caninos como hospedadores defini [...] tivos. Los huevos del parásito se obtuvieron de heces de caninos infectados naturalmente y se conservaron refrigerados en agua. Se incubaron 7 días a 25°C para que desarrollaran los coracidios y se pusieron en recipientes que contenían a los copépodos mencionados. Al cabo de 12 días a 22,6°C (promedio) se hallaron procercoides maduros en ellos y se agregaron 10 renacuajos de Bufo arenarum. Estos se examinaron por disección 22, 23, 61 y 107 días después, hallándose en todos 1 o más plerocercoides (Temperatura promedio: 24,9°C). El día 23, de 6 renacuajos se obtuvieron 49 plerocercoides, de los cuales se administraron 28, por vía oral, a una perra. El día 107, 3 de 11 plerocercoides obtenidos de un renacuajo se le dieron a otra perra por la misma vía. Se hallaron huevos del cestode en las heces del primer canino a partir del día 22 posterior a la infección (p.i.) y a los 30 días p.i., segmentos de estróbila. En el segundo canino se hallaron huevos a los 30 días p.i.. Abstract in english Experiments were performed in order to develop the life cycle of Diphyllobothrium erinaceieuropei Rudolphi 1819 (Cestoda, Pseudophyllidea) in Paracyclops fimbriatus and Bufo arenarum as intermediate hosts and dogs as definitive hosts. The eggs of Diphyllobothrium erinaceieuropei from faeces of natur [...] ally infected dogs were kept refrigered, in water. In order to obtain coracidiums they were incubated at 25°C, and then were placed in a flask which contained Paracyclops fimbriatus. The copepods were observed to be infected with procercoids 12 days after, (mean temperature 22.6°C) and then, ten tadpoles of Bufo arenarum were put into the same flask. The tadpoles were examined 22, 23, 61 and 107 days later, finding plerocercoids in all them (mean temperature 24.9°C). On the 23th day, 49 plerocercoids were removed from 6 tadpoles and 28 of them were fed to a bitch. On the 107th day, 11 plerocercoids were recovered from a dead tadpole and 3 of them were fed to another bitch. In the faeces of the first bitch there were observed the eggs of Diphyllobothrium erinaceieuropei 22 days post infection (d.p.i.) and part of the strobila 30 d.p.i.. In the faeces of the second bitch the eggs were found 30 d.p.i..

Lucila, Venturini.

1989-10-01

187

Effect of parathyroid hormone on transport by toad and turtle bladder  

International Nuclear Information System (INIS)

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 H2O transport by directly stimulating calcium uptake. The current study was designed to compare the effects of PTH and the calcium ionophore, A23187, on H2O and Na transport and H? secretion in toad and turtle bladders. In toad bladder, PTH and A23187 decreased arginine vasopressin (AVP)-stimulated H2O flow and short-circuit current (SCC) after 60 min serosal incubation. In turtle bladder A23187 decreased SCC to 79.3 +/- 3.6% of base line (P + secretion in turtle bladders. Both PTH and A23187 increased 45Ca uptake in toad bladder epithelial cells; only A23187 increased 45Ca 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 differentt

188

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

Science.gov (United States)

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. PMID:24936876

Brown, Gregory P; Shine, Richard

2014-01-01

189

Invasive species as drivers of evolutionary change: cane toads in tropical Australia.  

Science.gov (United States)

The arrival of an invasive species can have wide-ranging ecological impacts on native taxa, inducing rapid evolutionary responses in ways that either reduce the invader's impact or exploit the novel opportunity that it provides. The invasion process itself can cause substantial evolutionary shifts in traits that influence the invader's dispersal rate (via both adaptive and non-adaptive mechanisms) and its ability to establish new populations. I briefly review the nature of evolutionary changes likely to be set in train by a biological invasion, with special emphasis on recent results from my own research group on the invasion of cane toads (Rhinella marina) through tropical Australia. The toads' invasion has caused evolutionary changes both in the toads and in native taxa. Many of those changes are adaptive, but others may result from non-adaptive evolutionary processes: for example, the evolved acceleration in toad dispersal rates may be due to spatial sorting of dispersal-enhancing genes, rather than fitness advantages to faster-dispersing individuals. Managers need to incorporate evolutionary dynamics into their conservation planning, because biological invasions can affect both the rates and the trajectories of evolutionary change. PMID:25568034

Shine, Richard

2012-02-01

190

Passive and active defense in toads: the parotoid macroglands in Rhinella marina and Rhaebo guttatus.  

Science.gov (United States)

Amphibians have many skin poison glands used in passive defense, in which the aggressor causes its own poisoning when biting prey. In some amphibians the skin glands accumulate in certain regions forming macroglands, such as the parotoids of toads. We have discovered that the toad Rhaebo guttatus is able to squirt jets of poison towards the aggressor, contradicting the typical amphibian defense. We studied the R. guttatus chemical defense, comparing it with Rhinella marina, a sympatric species showing typical toad passive defense. We found that only in R. guttatus the parotoid is adhered to the scapula and do not have a calcified dermal layer. In addition, in this species, the plugs obstructing the glandular ducts are more fragile when compared to R. marina. As a consequence, the manual pressure necessary to extract the poison from the parotoid is twice as high in R. marina when compared to that used in R. guttatus. Compared to R. marina, the poison of R. guttatus is less lethal, induces edema and provokes nociception four times more intense. We concluded that the ability of R. guttatus to voluntary squirt poison is directly related to its stereotyped defensive behavior, together with the peculiar morphological characteristics of its parotoids. Since R. guttatus poison is practically not lethal, it is possibly directed to predators' learning, causing disturbing effects such as pain and edema. The unique mechanism of defense of R. guttatus may mistakenly justify the popular myth that toads, in general, squirt poison into people's eyes. PMID:24130001

Mailho-Fontana, Pedro L; Antoniazzi, Marta M; Toledo, Luís F; Verdade, Vanessa K; Sciani, Juliana M; Barbaro, Katia C; Pimenta, Daniel C; Rodrigues, Miguel T; Jared, Carlos

2014-02-01

191

Corticosterone-immune interactions during captive stress in invading Australian cane toads (Rhinella marina).  

Science.gov (United States)

Vertebrates cope with physiological challenges using two major mechanisms: the immune system and the hypothalamic pituitary-adrenal axis (e.g., the glucocorticoid stress response). Because the two systems are tightly integrated, we need simultaneous studies of both systems, in a range of species, to understand how vertebrates respond to novel challenges. To clarify how glucocorticoids modulate the amphibian immune system, we measured three immune parameters and plasma corticosterone (CORT), before and after inflicting a stressor (capture and captive confinement) on introduced cane toads (Rhinella marina) near their invasion front in Australia. Stress increased CORT levels, decreased complement lysis capacity, increased leukocyte oxidative burst, and did not change heterologous erythrocyte agglutination. The strength of the CORT response was positively correlated with leukocyte oxidative burst, and morphological features associated with invasiveness in cane toads (relative leg length) were correlated with stress responsiveness. No immune parameter that we measured was affected by a toad's infection by a parasitic nematode (Rhabdias pseudosphaerocephala), but the CORT response was muted in infected versus uninfected toads. These results illustrate the complex immune-stress interactions in wild populations of a non-traditional model vertebrate species, and describe immune adaptations of an important invasive species. PMID:22713726

Graham, Sean P; Kelehear, Crystal; Brown, Gregory P; Shine, Richard

2012-07-01

192

Frogs and toads in front of a mirror: lateralisation of response to social stimuli in tadpoles of five anuran species.  

Science.gov (United States)

Tadpoles of five anuran species were tested for preferences in the use of the eyes during inspection of their own visual image in a mirror. When tested in a tank with several small mirrors, tadpoles of five different species (Bufo bufo, Bufo viridis, Rana temporaria, Rana esculenta, Bombina variegata) preferentially approached and positioned themselves with the mirror located on their left side, thus looking at the image with the monocular field of their left eye. Similar results were obtained with tadpoles of R. temporaria tested in a simple task in which they had to choose approaching one or other of two large mirrors located on their left and right side. Control experiment showed that the behavioural asymmetry was not due to motor preferences and that it was independent of morphological asymmetries in the positions of the spiracles. This is the first demonstration of a functional visual lateralisation among juvenile amphibia before metamorphosis. PMID:12191829

Bisazza, Angelo; De Santi, Andrea; Bonso, Silvia; Sovrano, Valeria Anna

2002-08-21

193

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  

Science.gov (United States)

(1) DDT, dieldrin, and heptachlor were each applied to separate replicate plots in a hay field at 0.6, 2.2, or 9.0 kg/ha. For 11 yr thereafter, soil and earthworms were analysed for residues. (2) The average ratios of residues in earthworms (dry weight) to residues in soil (dry weight) were: total DDT, 5; dieldrin, 8; and heptachlor epoxide, 10. The average time for the initial residues in soil to be reduced by 50% were: total DDT, 3.2 yr; dieldrin, 5.1 yr; and heptachlor epoxide, 3.2 yr. The corresponding times for residues in earthworms were: total DDT, 3.2 yr; dieldrin, 2.6 yr; and heptachlor epoxide, 3.0 yr. (3) DDE was most persistent, and in plots treated at 9.0 kg/ha its concentration remained constant at about 0.4 ppm in soil and about 7 ppm in earthworms. (4) When applied at 9.0 kg/ha, DDT accumulated in earthworms to concentrations (32 ppm) which laboratory studies have shown to be hazardous to some sensitive bird species. When heptachlor was applied at 2.2 or 9.0 kg/ha, heptachlor epoxide in earthworms reached concentrations (8 ppm) potentially hazardous to woodcock. Dieldrin remained at potentially hazardous concentrations (8 ppm) for 3 yr in plots treated with 2.2 kg/ha and for 11 yr in plots treated with 9.0 kg/ha.

Shaffer, H.B.; Fellers, G.M.; Magee, A.; Voss, S.R.

2000-01-01

194

Antifungal effects of Ficus sycomorus and Pergularia tomentosa aqueous extracts on some organs in Bufo regularis treated with Aspergillus niger.  

Science.gov (United States)

The antifungal efficacy of Ficus sycomorus and Pergularia tomentosa plant extracts on Bufo regularis experimentally infected with Aspergillus niger was studied. After an oral administration of the pathogen for 15 days, the blood, kidney and liver were examined. Treatment with A. niger produced a reduction in red blood count cells and hemoglobin content. Also, both livers and kidneys revealed marked destruction and degenerative changes. These changes included congestion of blood vessels, leukocytic infiltration, and cytoplasmic vacuolization of the hepatocytes. As well as complete destruction of the cellular boundaries of the tubular epithelia, inflammatory leukocytes between the intertubular spaces, destruction and necrosis in renal tubule cells and the swollen glomeruli with wide glomerular spaces were seen. Pretreatment with F. sycomorus and P. tomentosa plant extracts 1h prior the administration of A. niger for two weeks improved blood parameters and protected against hepatic and renal damage as observed from histological examination and reduced spore numbers in culture media on these organs. PMID:21996552

Bekheet, Souad H M; Abdel-Motaal, Fatma F; Mahalel, Usama A

2011-12-01

195

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

Directory of Open Access Journals (Sweden)

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

Miranda, Leandro Andrés

1996-01-01

196

Regulation of the formation and water permeability of endosomes from toad bladder granular cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Osmotic water permeability (Pf) in toad bladder is regulated by the vasopressin (VP)-dependent movement of vesicles containing water channels between the cytoplasm and apical membrane of granular cells. Apical endosomes formed in the presence of serosal VP have the highest Pf of any biological or artificial membrane (Shi and Verkman. 1989. J. Gen. Physiol. 94:1101-1115). We examine here: (a) the influence of protein kinase A and C effectors on transepithelial Pf (Pfte) in intact bladders and ...

1990-01-01

197

Fast and slow voltage modulation of apical Cl- permeability in toad skin at high [K+  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The influence of voltage on the conductance of toad skin was studied to identify the time course of the activation/deactivation dynamics of voltage-dependent Cl- channels located in the apical membrane of mitochondrion-rich cells in this tissue. Positive apical voltage induced an important conductance inhibition which took a few seconds to fully develop and was instantaneously released by pulse inversion to negative voltage, indicating a short-duration memory of the inhibiting factors. Sinuso...

Procopio J.

1997-01-01

198

QUATERNARY DIVISION OPERATION BASED ON ALL- TERAHERTZ OPTICAL ASYMMETRIC DEMULTIPLEXER (TOAD)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Quaternary division based on all Terahertz Optical Asymmetric Demultiplexer (TOAD) is proposed. It shows quaternary division operation based on discrete-detect zero circuit using T-gate. In this present work all optical scheme of the different quaternary logical states are represented by different polarized state of light. Introducing the discrete-detect zero circuit reduces the overall number of the T-gates in the division operation and the number of T-gate incoming data transmission ...

Al-saffar, Alaa A.; Karim, Doaa A.

2014-01-01

199

The declining spadefoot toad Pelobates fuscus: calling site choice and conservation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigated whether local biotic and abiotic conditions could explain the occurrence of calling males of the declining spadefoot toad Pelobates fuscus in 72 ponds in southern Sweden. The ponds covered the entire distribution range of P. fuscus and were monitored during the breeding season in 2000. Calling males were found in 33 ponds. representing ca 50% of all known ponds for the species ill Sweden. They had a non-random distribution and a discriminant analysis including 19 environmental...

Nystro?m, Per; Birkedal, L.; Dahlberg, C.; Bro?nmark, Christer

2002-01-01

200

Goal orientation by geometric and feature cues: spatial learning in the terrestrial toad Rhinella arenarum.  

Science.gov (United States)

Although of crucial importance in vertebrate evolution, amphibians are rarely considered in studies of comparative cognition. Using water as reward, we studied whether the terrestrial toad, Rhinella arenarum, is also capable of encoding geometric and feature information to navigate to a goal location. Experimental toads, partially dehydrated, were trained in either a white rectangular box (Geometry-only, Experiment 1) or in the same box with a removable colored panel (Geometry-Feature, Experiment 2) covering one wall. Four water containers were used, but only one (Geometry-Feature), or two in geometrically equivalent corners (Geometry-only), had water accessible to the trained animals. After learning to successfully locate the water reward, probe trials were carried out by changing the shape of the arena or the location of the feature cue. Probe tests revealed that, under the experimental conditions used, toads can use both geometry and feature to locate a goal location, but geometry is more potent as a navigational cue. The results generally agree with findings from other vertebrates and support the idea that at the behavioral-level geometric orientation is a conserved feature shared by all vertebrates. PMID:25283747

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

2015-01-01

 
 
 
 
201

The effects of experimentally infecting Australian tree frogs with lungworms (Rhabdias pseudosphaerocephala) from invasive cane toads.  

Science.gov (United States)

Invasive species may transmit novel pathogens to native taxa, and lacking a history of coevolutionary interactions with the pathogen, the new hosts may be severely affected. Cane toads (Rhinella marina) were introduced to Australia in 1935, bringing with them a lungworm (Rhabdias pseudosphaerocephala) not found in Australian frogs. Previous studies suggest that most frog species are unaffected by this parasite, but one tree-frog (Litoria caerulea) can harbour high numbers of lungworm. More detailed laboratory studies confirm and extend the earlier results on L. caerulea and show that Rhabdias infection severely depresses the viability of metamorphs of an allied tree-frog species, Litoria splendida. Parasitic larvae infected both of these two closely related tree-frog species, but the two anurans differed in the consequences of infection. Parasitism reduced the survivorship of L. splendida and the stamina of both species. Lungworms did not consistently reduce growth rates or affect heart rates in either tree-frog species. Although L. splendida is potentially vulnerable to the arrival of toad-transported lungworms, rates of host-switching may be reduced by low levels of habitat overlap between the frogs (which are rock-dwelling and arboreal) and the toads (which are terrestrial and most abundant in disturbed habitats). PMID:21624371

Pizzatto, Lígia; Shine, Richard

2011-08-01

202

Reduce torques and stick the landing: limb posture during landing in toads.  

Science.gov (United States)

A controlled landing, where an animal does not crash or topple, requires enough stability to allow muscles to effectively dissipate mechanical energy. Toads (Rhinella marina) are exemplary models for understanding the mechanics and motor control of landing given their ability to land consistently during bouts of continuous hopping. Previous studies in anurans have shown that ground reaction forces (GRFs) during landing are significantly higher compared with takeoff and can potentially impart large torques about the center of mass (COM), destabilizing the body at impact. We predict that in order to minimize such torques, toads will align their COM with the GRF vector during the aerial phase in anticipation of impact. We combined high-speed videography and force-plate ergometry to quantify torques at the COM and relate the magnitude of torques to limb posture at impact. We show that modulation of hindlimb posture can shift the position of the COM by about 20% of snout-vent length. Rapid hindlimb flexion during the aerial phase of a hop moved the COM anteriorly and reduced torque by aligning the COM with the GRF vector. We found that the addition of extrinsic loads did not significantly alter landing behavior but did change the torques experienced at impact. We conclude that anticipatory hindlimb flexion during the aerial phase of a hop is a critical feature of a mechanically stable landing that allows toads to quickly string together multiple, continuous hops. PMID:25320271

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

2014-10-15

203

Curcumin and its Effect on Cytochrome P450 and GST in Toad Liver Tumor Induced by DMBA  

Directory of Open Access Journals (Sweden)

Full Text Available Curcumin has been used as a colouring agent and spice in many food. The present results clearly demonstrated that toads received 0.5 mg curcumin and 0.5 mg DMBA/toad, 3 times/week for 12 weeks, showed a significant decrease in tumor incidence (3 out of 50 cases in comparison with that treated with DMBA alone (12 out of 50 cases. At the same time, curcumin reduce the activity of liver microsomal cytochrome P450s and cytosolic GTSS enzymes in toads previously treated with DMBA. The present data suggest that curcumin decrease incidence of liver tumor in toads through inhibition of cytochrome P45O and GST activities. The present report was undertaken for two reasons. First to determine whether curcumin, which are widely used in food have anticarcinogenic effect on the liver of the Egyptian toad. Second, are curcumin effect on microsomal cytochrome P450 and GST activities to shed more light on the mechanisms (s of action.

H. Abdel-Latif

1999-01-01

204

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

Science.gov (United States)

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

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

2013-01-01

205

The straight and narrow path: the evolution of straight-line dispersal at a cane toad invasion front.  

Science.gov (United States)

At the edge of a biological invasion, evolutionary processes (spatial sorting, natural selection) often drive increases in dispersal. Although numerous traits influence an individual's displacement (e.g. speed, stamina), one of the most important is path straightness. A straight (i.e. highly correlated) path strongly enhances overall dispersal rate relative to time and energetic cost. Thus, we predict that, if path straightness has a genetic basis, organisms in the invasion vanguard will exhibit straighter paths than those following behind. Our studies on invasive cane toads (Rhinella marina) in tropical Australia clearly support this prediction. Radio-tracking of field-collected toads at a single site showed that path straightness steadily decreased over the first 10 years post-invasion. Consistent with an evolved (genetic) basis to that behavioural shift, path straightness of toads reared under common garden conditions varied according to the location of their parents' origin. Offspring produced by toads from the invasion vanguard followed straighter paths than did those produced by parents from long-established populations. At the individual level, offspring exhibited similar path straightness to their parents. The dramatic acceleration of the cane toad invasion through tropical Australia has been driven, in part, by the evolution of a behavioural tendency towards dispersing in a straight line. PMID:25297862

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

2014-11-22

206

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

Science.gov (United States)

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 multiple eco-physiological levels through impacts on endocrine physiology, performance and potentially fitness traits (e.g. reproductive output). PMID:24643017

Narayan, Edward J; Hero, Jean-Marc

2014-01-01

207

Physiology of invasion: cane toads are constrained by thermal effects on physiological mechanisms that support locomotor performance.  

Science.gov (United States)

Understanding the mechanisms that constrain the invasiveness of introduced animals is essential for managing invasions and for predicting their limits. In most vertebrate species, the capacity for invasion relies upon the physiological systems that support locomotion, and oxygen transport and metabolism may become limiting as environmental temperatures increase as predicted by the oxygen limitation hypothesis. Here we test the oxygen limitation hypothesis and propose the alternative hypothesis that within-individual plasticity will compensate for thermal variation. We show that during exercise in the invasive cane toad (Rhinella marina) oxygen transport by the cardiovascular system was maximised in warm-acclimated toads at high (30°C) temperatures, and that oxygen content of arterial blood was not affected by temperature. Resting oxygen consumption remained stable across a 10°C temperature range (20-30°C) when toads were allowed to acclimate, so that there was no increase in resting oxygen demand that could lead to a decrease in aerobic scope at high temperatures. Additionally, temperature acclimation had no effect on arterial-venous differences in oxygen partial pressures. Toads relied more on glycolytic ATP production at low temperatures to support locomotor activity. Mitochondrial capacities (citrate synthase and cytochrome c oxidase activities) were greatest at warmer temperatures. Interestingly, the metabolic cost of exercise increased at low temperatures. In contradiction to predictions by the oxygen limitation hypothesis, aerobic performance was not limited by high temperatures. On the contrary, the relatively slow advance of cane toads to cooler climates can be explained by the constraints of low temperatures on the physiological systems supporting locomotion. It is likely that human-induced global warming will facilitate invasions of environments that are currently too cool to support cane toads. PMID:21490252

Seebacher, Frank; Franklin, Craig E

2011-05-01

208

Mortalities of the Green Toad (Epidalea viridis (Laurenti, 1768 in Urban Environment: A Case Study from the City of Plovdiv  

Directory of Open Access Journals (Sweden)

Full Text Available The current study analyzes the types of mortalities of the green toad (Epidalea viridis in the city of Plovdiv. Among all recorded mortalities (n=42, the road kill was the most common cause of death (65 % of the cases, followed by killing by humans (usually children – 31%. Killing of green toads by dogs (2% and domestic cats (2% has the lowest impact. Both most significant factors (road kill and killing by humans affect mainly the adult specimens. No statistically significant difference between the mortalities of the two sexes was detected.

Miglena V. Valkanova

2009-08-01

209

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

Directory of Open Access Journals (Sweden)

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

Pablo García-Díaz

2011-02-01

210

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

Science.gov (United States)

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.

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

2011-01-01

211

Covalent labeling of hydrosmotic toad bladder receptors with an antagonist of vasotocin  

International Nuclear Information System (INIS)

A photoreactive analogue of vasotocin, [1-desamino,4-lysine(azidobenzoyl),8-arginine]vasotocin (4-N3-AVT), has been examined in the isolated toad urinary bladder for biological activity and binding to hormonal receptors. Although 4-N3-AVT induced only a small increase in bladder permeability to water, it behaved as a potent inhibitor of hydrosmotic action of [8-arginine]vasotocin (AVT) and [8-arginine]vasopressin (AVP). The inhibitory action of 4-N3-AVT was readily reversed on removal of the analogue from the serosal bathing solution. On the other hand, when bladders were exposed to 4-N3-AVT in the presence of long wavelength UV light (365 nm), the inhibition by 4-N3-AVT was not reversed on washout of the analogue. The dose of vasopressin required for a half-maximal response (ED50 value) was increased from 5 X 10(-9) to 1.3 X 10(-7) M in bladders photolabeled with 4-N3-AVT and the maximal response capacity of the tissue (intrinsic activity) was reduced to 79% of nonphotolabeled controls. A crude membrane preparation derived from bladders photolabeled with 4-N3-AVT contained 72 fmol of specific binding sites for tritium-labeled vasopressin per milligram protein, whereas nonphotolabeled controls had 136 fmol of specific binding sites per milligram protein. These observations suggest that 4-N3-AVT forms a covalent bond with hydrosmotic receptors in the presence of UV light. This is the first antagonistic photoaffinity analogue observed in the toad bladder and it may servserved in the toad bladder and it may serve as a useful tool for analyzing the cellular mechanism of action of antidiuretic hormone

212

Aldosterone increases the apical Na+ permeability of toad bladder by two different mechanisms.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aldosterone-induced augmentation of Na+ transport in toad bladder was analyzed by comparing the hormonal actions on the transepithelial short-circuit current and on the amiloride-sensitive 22Na+ uptake in isolated membrane vesicles. Incubating bladders with 0.5 microM aldosterone for 3 hr evoked more than a 2-fold increase of the short-circuit current (because of the activation or insertion of apical amiloride-blockable channels) but had no effect on the amiloride-sensitive Na+ transport ...

Asher, C.; Garty, H.

1988-01-01

213

Host-parasite relationships during a biologic invasion: 75 years postinvasion, cane toads and sympatric Australian frogs retain separate lungworm faunas.  

Science.gov (United States)

Invasive species may carry with them parasites from their native range, differing from parasite taxa found in the invaded range. Host switching by parasites (either from the invader to native fauna or from native fauna to the invader) may have important consequences for the viability of either type of host (e.g., their survivorship, fecundity, dispersal ability, or geographic distribution). Rhabdias pseudosphaerocephala (Nematoda) is a common parasite of cane toads (Rhinella marina) in the toad's native range (South and Central America) and also in its introduced Australian range. This lungworm can depress host viability and is capable of infecting Australian frogs in laboratory trials. Despite syntopy between toads and frogs for up to 75 yr, our analyses, based on DNA sequence data of lungworms from 80 frogs and 56 toads, collected from 2008 to 2011, did not reveal any cases of host switching in nature: toads and native frogs retain entirely different lungworm faunas. All lungworms in cane toads were the South and Central American species Rhabdias pseudosphaerocephala, whereas Australian frogs contained at least four taxa (mostly undescribed and currently lumped under the name Rhabdias cf. hylae). General patterns of prevalence and intensity, based on the dissection of 1,315 frogs collected between 1989 and 2011 across the toads' Australian range, show that these Australian endemic Rhabdias spp. are widely distributed geographically and across host taxa but are more common in some frog species (especially, large-bodied species) than they are in others. PMID:23060496

Pizzatto, Lígia; Kelehear, Crystal; Dubey, Sylvain; Barton, Diane; Shine, Richard

2012-10-01

214

Individual variation and repeatability in urinary corticosterone metabolite responses to capture in the cane toad (Rhinella marina).  

Science.gov (United States)

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. PMID:22137908

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

2012-01-15

215

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

Science.gov (United States)

...FXES11130200000F5-112-FF02ENEH00] Emergency Exemption; Issuance of Emergency Permit To Salvage Houston Toads Affected by a Wildfire in Bastrop County, TX AGENCY: Fish and Wildlife Service, Interior. ACTION: Notice of issuance of endangered species...

2012-02-09

216

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

Directory of Open Access Journals (Sweden)

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

Ursula DICKE, Antje HEIDORN, Gerhard ROTH

2011-12-01

217

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

International Nuclear Information System (INIS)

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

218

Reassessment of the environmental model of developmental polyphenism in spadefoot toad tadpoles.  

Science.gov (United States)

Polyphenism is the expression of multiple, discrete phenotypes from one genotype, and understanding the environmental factors that trigger development of alternative phenotypes is a critical step toward understanding the evolution of polyphenism and its developmental control. While much is known about the ecology of the well-known carnivore/omnivore polyphenism in spadefoot toad tadpoles, the environmental cues for the development of the specialized carnivore phenotype are not completely clear. We examined 27 different experimental treatments in two spadefoot toad species and used over 1,000 tadpoles in an attempt to elucidate those cues. While only 44 carnivores developed in these treatments, they were concentrated at cooler water temperatures and a diet that included fairy shrimp. However, while a diet of fairy shrimp promoted carnivore development, it was not necessary for inducing carnivore development at lower and intermediate water temperatures. Evidence also suggested a role for social inhibition that limited the proportion of interacting tadpoles that become carnivores. Tadpoles of Spea multiplicata grew larger at cooler temperatures and larger when their diets included fairy shrimp, whereas tadpoles of S. bombifrons grew larger at warmer temperatures and when their diets did not include fairy shrimp. These results indicate that carnivore induction can occur through different cues and that our current model for carnivore development is too limited. Finally, we argue that the carnivore/omnivore spadefoot system is neither a polyphenism nor a polymorphism but is a continuously distributed plasticity. PMID:20842381

Storz, Brian L; Heinrichs, Jessica; Yazdani, Arash; Phillips, Ryan D; Mulvey, Brett B; Arendt, Jeff D; Moerland, Timothy S; Travis, Joseph

2011-01-01

219

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

Science.gov (United States)

Body size at metamorphosis is a key trait in species (such as many anurans) with biphasic life-histories. Experimental studies have shown that metamorph size is highly plastic, depending upon larval density and environmental conditions (e.g. temperature, food supply, water quality, chemical cues from conspecifics, predators and competitors). To test the hypothesis that this developmental plasticity is adaptive, or to determine if inducing plasticity can be used to control an invasive species, we need to know whether or not a metamorphosing anuran's body size influences its subsequent viability. For logistical reasons, there are few data on this topic under field conditions. We studied cane toads (Rhinella marina) within their invasive Australian range. Metamorph body size is highly plastic in this species, and our laboratory studies showed that larger metamorphs had better locomotor performance (both on land and in the water), and were more adept at catching and consuming prey. In mark-recapture trials in outdoor enclosures, larger body size enhanced metamorph survival and growth rate under some seasonal conditions. Larger metamorphs maintained their size advantage over smaller siblings for at least a month. Our data support the critical but rarely-tested assumption that all else being equal, larger body size at metamorphosis is likely to enhance an individual's long term viability. Thus, manipulations to reduce body size at metamorphosis in cane toads may help to reduce the ecological impact of this invasive species. PMID:23922930

Cabrera-Guzmán, Elisa; Crossland, Michael R; Brown, Gregory P; Shine, Richard

2013-01-01

220

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

Science.gov (United States)

The impact of parasites on host populations depend upon parasite prevalence and intensity. Understanding how infection dynamics change through time following a host population's initial exposure to the parasite is fundamental to host-parasite biology. We studied an invasive host (the cane toad, Rhinella marina) currently undergoing range expansion - a process through which this host's range is expanding faster than that of its lung parasites (the nematode, Rhabdias pseudosphaerocephala), such that hosts at the expanding range edge remain parasite-free for several years. It was predicted that parasite intensity and prevalence would be affected by host characteristics (e.g., size, sex), environmental conditions (e.g., seasons, habitat type), and time since parasite arrival in the newly established invading host population. Over 2,400 cane toads were sampled at 10 sites in recently established toad populations in the highly seasonal monsoonal tropics of northern Australia. The sampling spanned 14 consecutive 3 month seasons commencing in the early stages of lungworm establishment in those toad populations. Both parasite prevalence and intensity increased with host body size but were unaffected by host sex. Prevalence and intensity were highest during drier times of year and in drier habitats (i.e., sites lacking permanent waterbodies). These changes in parasite prevalence may reflect a trend for saturated soil to reduce parasite survival during the free-living infective stage, and to allow anuran hosts to disperse widely (thus reducing the transfer of directly transmitted parasites between hosts). Conversely, dry conditions induce toads to aggregate in moist dry-season refugia where conditions may be more conducive to direct transmission of infective parasitic larvae between hosts. PMID:23747925

Pizzatto, Lígia; Kelehear, Crystal; Shine, Richard

2013-08-01

 
 
 
 
221

Effects of temperature on urinary corticosterone metabolite responses to short-term capture and handling stress in the cane toad (Rhinella marina).  

Science.gov (United States)

Extreme temperature can cause metabolic, immune and behavioural changes in amphibians. Short-term stress hormonal response via increased secretion of corticosterone enables amphibians to make necessary physiological and behavioural adjustments for coping with stressors. The effect of temperature on short-term corticosterone responses has not been studied in amphibians. In this study, this relationship was evaluated in adult male cane toads (Rhinella marina). We acclimated male toads (n=24 toads per group) at low, medium and high temperature (15, 25 or 35°C) under controlled laboratory conditions for a 14 day period. After thermal acclimation, short-term corticosterone responses were evaluated in the toads subjected to a standard capture and handling stress protocol over a 24h period. Corticosterone metabolites in toad urine were measured via enzyme-immunoassay. During acclimation, mean baseline urinary corticosterone level increased after transfer of the toads from wild into captivity and returned to baseline on day 14 of acclimation for each of the three temperatures. At the end of the 14 days of thermal acclimation period, baseline corticosterone level were highest for toad group at 35°C and lowest at 15°C. All toads generated urinary corticosterone responses to the standard capture and handling stressor for each temperature. Both individual and mean short-term corticosterone responses of the toads were highest at 35°C and lowest at 15°C. Furthermore, Q(10) values (the factor by which the reaction rate increases when the temperature is raised by 10°) were calculated for mean corrected integrated corticosterone responses as follows; (15-35°C) Q(10)=1.51, (15-25°C) Q(10)=1.60; (25-35°C) Q(10)=1.43. Both total and corrected integrated corticosterone responses were highest for toads at 35°C followed by 25°C and lowest for the 15°C toad group. Overall, the results have demonstrated the thermodynamic response of corticosterone secretion to short-term capture and handling stress in an amphibian species. PMID:22728158

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

2012-09-01

222

Temporal Population Genetic Instability in Range-Edge Western Toads, Anaxyrus boreas.  

Science.gov (United States)

In this article, we address the temporal stability of population genetic structure in a range-edge population that is undergoing continual, short-distance colonization events. We sampled western toad, Anaxyrus boreas, breeding populations over 2 seasons near their northern range limit in southeast Alaska. We sampled 20 ponds each during the summers of 2008 and 2009, with 14 ponds sampled in both summers. We found considerable turnover in the population genetic relationships among ponds in those 2 seasons, as well as biologically meaningful genetic differentiation between years within some ponds. We found relatively consistent relationships between major population centers, whereas the relationships between the central ponds and smaller, outlying populations differed year to year. This finding indicates that multiple years of genetic sampling may be important for understanding the genetic landscape of some populations. PMID:25433082

Holmes, Iris

2015-01-01

223

The complete mitochondrial genome of Grumgzimailo's toad-headed agama, Phrynocephalus grumgrizimailoi (Reptilia, Squamata, Agamidae).  

Science.gov (United States)

Abstract Polymerase chain reaction (PCR), long-and-accurate PCR and directly sequencing by primer walking was used to sequenced he complete mitochondrial genome sequence of Grumgzimailo's toad- headed agama, Phrynocephalus grumgrizimailoi. The Genbank accession was KM093859. There was 16,301?bp in length of the entire mitochondrial genome of P. grumgrizimailoi and the content of A, T, C, and G were 36.4%, 26.5%, 25.0% and 12.1%, respectively, that was similar to most vertebrate. The complete mitochondrial genome of P. grumgrizimailoi contain 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, plus 2 control regions and was similar to those of other Phrynocephalus sand lizards in gene arrangement and composition, except P. przewalskii and P. versicolor. The complete mitochondrial genome of P. grumgrizimailoi provided fundamental data for resolving phylogenetic relationship problems related to Agaimidae and genus Phrynocephalus. PMID:25208174

Shuang, Luo; Liu, Li-Jun; Song, Sen

2014-09-10

224

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

Science.gov (United States)

A chromosome study was carried out on a number of European and Central Asiatic diploid green toad populations by means of standard and various other chromosome banding and staining methods (Ag-NOR-, Q-, CMA3-, late replicating [LR] banding pattern, C-and sequential C-banding + CMA3 + DAPI). This study revealed the remarkable karyological uniformity of specimens from all populations, with the only exception being specimens from a Moldavian population, where one chromosome pair was heteromorphic. Though similar in shape, size and with an identical heterochromatin distribution,the difference in the heteromorphic pair was due to a large inverted segment on its long arms. This heteromorphism was restricted to females, suggesting a female heterogametic sex chromosome system of ZZ/ZW type at a very early step of differentiation. PMID:17762149

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

2007-06-01

225

Isolation of a Bohle-like iridovirus from boreal toads housed within a cosmopolitan aquarium collection.  

Science.gov (United States)

A captive 'survival assurance' population of 56 endangered boreal toads Anaxyrus boreas boreas, housed within a cosmopolitan collection of amphibians originating from Southeast Asia and other locations, experienced high mortality (91%) in April to July 2010. Histological examination demonstrated lesions consistent with ranaviral disease, including multicentric necrosis of skin, kidney, liver, spleen, and hematopoietic tissue, vasculitis, and myriad basophilic intracytoplasmic inclusion bodies. Initial confirmation of ranavirus infection was made by Taqman real-time PCR analysis of a portion of the major capsid protein (MCP) gene and detection of iridovirus-like particles by transmission electron microscopy. Preliminary DNA sequence analysis of the MCP, DNA polymerase, and neurofilament protein (NFP) genes demonstrated highest identity with Bohle iridovirus (BIV). A virus, tentatively designated zoo ranavirus (ZRV), was subsequently isolated, and viral protein profiles, restriction fragment length polymorphism analysis, and next generation DNA sequencing were performed. Comparison of a concatenated set of 4 ZRV genes, for which BIV sequence data are available, with sequence data from representative ranaviruses confirmed that ZRV was most similar to BIV. This is the first report of a BIV-like agent outside of Australia. However, it is not clear whether ZRV is a novel North American variant of BIV or whether it was acquired by exposure to amphibians co-inhabiting the same facility and originating from different geographic locations. Lastly, several surviving toads remained PCR-positive 10 wk after the conclusion of the outbreak. This finding has implications for the management of amphibians destined for use in reintroduction programs, as their release may inadvertently lead to viral dissemination. PMID:25266901

Cheng, Kwang; Jones, Megan E B; Jancovich, James K; Burchell, Jennifer; Schrenzel, Mark D; Reavill, Drury R; Imai, Denise M; Urban, Abby; Kirkendall, Maryanne; Woods, Leslie W; Chinchar, V Gregory; Pessier, Allan P

2014-09-30

226

Bm-TFF2, a toad trefoil factor, promotes cell migration, survival and wound healing  

International Nuclear Information System (INIS)

Research highlights: ? Bm-TFF2 binds to epithelial cells and induces cell migration and wound healing. ? Bm-TFF2 suppresses cell apoptosis. ? Bm-TFF2 has no effect on cell proliferation. -- Abstract: Toad skin is naked and continually confronted by various injurious factors. Constant skin renewal and repairs occur frequently. However, the mechanisms of the renewal and repair have not clearly elucidated. In our previous work, a trefoil factor (TFF), Bm-TFF2, has been purified from the Bombina maxima skin and characterized as a platelet agonist. The mRNA of TFFs in toad skin was up-regulated greatly during the metamorphosis, indicating a pivotal role of TFFs in amphibian skin. Here, we presented the effects of Bm-TFF2 on the cell migration, apoptosis and proliferation. Bm-TFF2 bound to epithelial cells and showed strong cell motility activity. At the concentrations of 1-100 nM, Bm-TFF2-induced migration of human epithelial AGS and HT-29 cells, and rat intestinal epithelial IEC-6 cell lines. The in vitro wound healing assay also verified the activity of Bm-TFF2. Bm-TFF2 could also inhibit cell apoptosis induced by ceramide and sodium butyrate. The cell migration-promoting activity was abolished by MEK1 inhibitors, U0126 and PD98059, suggesting that ERK1/2 activation is crucial for Bm-TFF2 to stimulate cell migration. Taken together, Bm-TFF2 promoted wound healing by stimulating cell migration via MAPK pathway and preventing cell apoptosis. The potent biological activity of Bm-TFF2 makes it a useful molecular tool for further studies of structure-function relationship of the related human TFFs.

227

Bm-TFF2, a toad trefoil factor, promotes cell migration, survival and wound healing  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} Bm-TFF2 binds to epithelial cells and induces cell migration and wound healing. {yields} Bm-TFF2 suppresses cell apoptosis. {yields} Bm-TFF2 has no effect on cell proliferation. -- Abstract: Toad skin is naked and continually confronted by various injurious factors. Constant skin renewal and repairs occur frequently. However, the mechanisms of the renewal and repair have not clearly elucidated. In our previous work, a trefoil factor (TFF), Bm-TFF2, has been purified from the Bombina maxima skin and characterized as a platelet agonist. The mRNA of TFFs in toad skin was up-regulated greatly during the metamorphosis, indicating a pivotal role of TFFs in amphibian skin. Here, we presented the effects of Bm-TFF2 on the cell migration, apoptosis and proliferation. Bm-TFF2 bound to epithelial cells and showed strong cell motility activity. At the concentrations of 1-100 nM, Bm-TFF2-induced migration of human epithelial AGS and HT-29 cells, and rat intestinal epithelial IEC-6 cell lines. The in vitro wound healing assay also verified the activity of Bm-TFF2. Bm-TFF2 could also inhibit cell apoptosis induced by ceramide and sodium butyrate. The cell migration-promoting activity was abolished by MEK1 inhibitors, U0126 and PD98059, suggesting that ERK1/2 activation is crucial for Bm-TFF2 to stimulate cell migration. Taken together, Bm-TFF2 promoted wound healing by stimulating cell migration via MAPK pathway and preventing cell apoptosis. The potent biological activity of Bm-TFF2 makes it a useful molecular tool for further studies of structure-function relationship of the related human TFFs.

Zhang, Yong [Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Yu, Guoyu [Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Department of Biochemistry, Kunming Medical College, Kunming, Yunnan 650032 (China); Xiang, Yang [Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Wu, Jianbo [Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223 (China); Jiang, Ping [Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Lee, Wenhui [Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223 (China); Zhang, Yun, E-mail: zhangy@mail.kiz.ac.cn [Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223 (China)

2010-07-30

228

Morphological and molecular characterization of Ortleppascaris sp. larvae, parasites of the cane toad Rhinella marina from eastern Amazonia.  

Science.gov (United States)

This study presents a new record for the occurrence of larval Ortleppascaris sp.(Sprent, 1978). The nematodes were collected from inside fibrous cysts found in the livers of cane toads, Rhinella marina (Linnaeus, 1758), captured in eastern Brazilian Amazonia. This is the first record of Ortleppascaris sp. larvae in both Brazil and this amphibian host, increasing its distribution in South America as well as expanding the number of helminths known to infect this toad. The detailed description of Ortleppascaris sp. provides new taxonomic data for these larvae, as well as sequences of the internal transcribed spacers and small subunit DNA segments, and the cytochrome oxidase I gene, which will, in time, contribute to a better understanding of the phylogeny of this group of parasites. PMID:22924910

e Silva, Jefferson P; Melo, Francisco T V; Silva, Luciana C N; Gonçalves, Evonnildo C; Giese, Elane G; Furtado, Adriano P; Santos, Jeannie N

2013-02-01

229

Assessment of Polycyclic Aromatic Hydrocarbon Contamination of Breeding Pools Utilized by the Puerto Rican Crested Toad, Peltophryne lemur  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Jenessa Gjeltema; Michael Stoskopf; Damian Shea; Ryan De Voe

2012-01-01

230

Calcium reduces the sodium permeability of luminal membrane vesicles from toad bladder. Studies using a fast-reaction apparatus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Regulation of the sodium permeability of the luminal membrane is the major mechanism by which the net rate of sodium transport across tight epithelia is varied. Previous evidence has suggested that the permeability of the luminal membrane might be regulated by changes in intracellular sodium or calcium activities. To test this directly, we isolated a fraction of the plasma membrane from the toad urinary bladder, which contains a fast, amiloride-sensitive sodium flux with characteristics simil...

1983-01-01

231

Inverse urinary corticosterone and testosterone metabolite responses to different durations of restraint in the cane toad (Rhinella marina).  

Science.gov (United States)

Non-invasive measurement of urinary corticosterone and testosterone metabolites in amphibians provides opportunities for endocrine studies of responses to physiological and psychological stressors. Typically, corticosterone metabolite concentrations increase in frog urine within 1-2h of a mild capture and handling stress protocol. However, no study has investigated the effect of duration of manual restraint on the changes in corticosterone and reproductive hormones in amphibians. We quantified urinary corticosterone and testosterone metabolite responses for 8h following various durations of manual restraint (control, 5, 15 or 30min) in adult male cane toads (Rhinella marina) under controlled laboratory conditions. All toads had a corticosterone stress response over 8h to our standard capture and handling stressor. The mean corticosterone stress response was significantly higher after 15 or 30min restraint in comparison to the control (no restraint) or to 5min restraint. Manual restraint for 5, 15 or 30min caused a significant reduction in urinary testosterone concentrations over 8h. We also provide a novel method of quantifying plasticity in corticosterone stress responses in amphibians with respect to restraint duration using the concept of a "reaction norm". The reaction norm, which was calculated as slope of the regression line of integrated corticosterone response against restraint duration, was 9.69 (pg corticosterone/?g creatinineh)/min for male toads. In summary, corticosterone and testosterone responses to restraint are affected by restraint duration in male toads. Glucocorticoid reaction norms can be applied to study the change in physiological stress hormonal response with respect to restraint duration in other amphibian species. PMID:23036735

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

2012-12-01

232

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

Directory of Open Access Journals (Sweden)

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

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

2011-12-01

233

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

Science.gov (United States)

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

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

2014-01-01

234

Size and sex matter: infection dynamics of an invading parasite (the pentastome Raillietiella frenatus) in an invading host (the cane toad Rhinella marina).  

Science.gov (United States)

Correlations between host phenotype and vulnerability to parasites can clarify the processes that enhance rates of parasitism, and the effects of parasites on their hosts. We studied an invasive parasite (the pentastome Raillietiella frenatus, subclass Pentastomida, order Cephalobaenida) infecting a new host (the invasive cane toad Rhinella marina), in tropical Australia. We dissected toads over a 27-month period to investigate seasonal changes in pentastome population dynamics and establish which aspects of host phenotype are related to infection. Pentastome prevalence and intensity varied seasonally; male toads were 4 times more likely to be infected than were females; and prevalence was highest in hosts of intermediate body size. The strong sex effect may reflect habitat or dietary divergence between the sexes, resulting in males encountering parasites more often. The relationship between pentastome prevalence and host size likely reflects a role for acquired immunity in preventing re-infection. Infection did not influence host body condition (fatbody size), suggesting that R. frenatus does not impose high energy costs in cane toads. Infected toads had heavier spleens (likely an immune response to infection) and larger testes (perhaps since reproductively active hosts have altered microhabitat use and/or immunocompetence) than did uninfected conspecifics. Although experimental studies are required to identify the causal bases of such patterns, our data confirm that infection status within a population can be strongly linked to host phenotypic traits. PMID:22814124

Kelehear, Crystal; Brown, Gregory P; Shine, Richard

2012-10-01

235

A Comparative Study of Morphology and Ecology of Bufo stomaticus (Lutken, 1864, (Anura: Bufonidae fromDistrictLarkana and Shikarpur, Pakistan  

Directory of Open Access Journals (Sweden)

Full Text Available In present investigation, characteristics of Morphology and Ecology of Bufo stomaticus (Lutken, 1864, (Anura: Bufonidae populations in two adjacent DistrictsvizLarkana and Shikarpur of Pakistan have been studied comparativelyfrom March to September 2012 to record morphological and ecological difference between them and also to know which districtprovides better environmental conditions to support their survival. Literature related with Taxonomy and water quality helped in determination of present study.Physical appearanceof both populations observed to be significantly different from each other but morphometric was measured to be relatively same. Habitats of B. stomaticus were analyzed by Physico-chemical parameters viz: pH, conductivity, Total dissolved solids, Chloride, Calcium, Magnesium, Potassium andIron. Most of the parameters were analyzed to be significantly differentbut within favorable level except Conductivity in both Districts.

Kalsoom Shaikh

2013-08-01

236

The complete mitochondrial genome of secret toad-headed agama, Phrynocephalus mystaceus (Reptilia, Squamata, Agamidae).  

Science.gov (United States)

The complete mitogenome sequence of a mystical lizard species Phrynocephalus mystaceus was determined using polymerase chain reaction and directly sequenced with a primer walking method. The complete mitogenome was 16,660 bp in length, containing 13 protein-coding genes, 22 tRNA genes, two rRNA genes and a control region (D-loop). The gene arrangement and composition of P. mystaceus was similar to most other vertebrates, but the Proline tRNA gene was translocated to be adjacent to tRNA-Phe gene. The D-loop consisted of two parts, with part I existing between the tRNA-Thr gene and tRNA-Pro gene and another part inserting between the tRNA-Phe and 12S rRNA. In part I, one conserved sequence (CSB I) could be identified. In part II, two pair of motifs, "TACAT" and its reverted and complemented sequence "ATGTA", could be found in the domain of an extended termination-associated sequence. The mitogenome sequence of P. mystaceus could contribute to a better solution of its phylogenetic position within toad-headed agamids based on the whole mitogenomic data. PMID:23488917

Chen, Dali; Guo, Xianguang; Li, Jun

2014-02-01

237

The complete mitochondrial genome of the Yarkand toad-headed agama, Phrynocephalus axillaris (Reptilia, Squamata, Agamidae).  

Science.gov (United States)

The complete mitochondrial genome of the Yarkand toad-headed agama Phrynocephalus axillaris, the first complete mitogenome from the genus Phrynocephalus, was determined. The total length of this complete mitogenome is 17,937 bp, containing 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 2 control regions (CRs). The overall base composition of the H-strand is 36.4% A, 26.0% T, 25.4% C, and 12.3% G. The gene arrangement and composition of the mitogenome are similar to those of other Agaminae lizards, albeit with one CR existing between the tRNA(Thr) gene and tRNA(Pro) gene and another CR containing 17 copies of 77-bp tandem repeats inserting between the tRNA(Phe) and 12S rRNA. The complete mitogenome sequence of P. axillaris provided fundamental data for resolving phylogenetic and genetic problems related to this species and genus Phrynocephalus. PMID:23327484

Li, Jun; Guo, Xianguang; Chen, Dali; Wang, Yuezhao

2013-06-01

238

Organization of afferents to the striatopallidal systems in the fire-bellied toad Bombina orientalis.  

Science.gov (United States)

The cerebral hemispheres of amphibians display paired dorsal and ventral striatum (commonly referred to as striatum proper and nucleus accumbens, respectively). Each striatal region is proposed to be closely associated with a pallidal structure located caudal to it to form a striatopallidal system. In the present study, afferents to the dorsal and ventral striatopallidal systems of the fire-bellied toad (Bombina orientalis) were investigated using the neuronal tracer biocytin. A quantitative analysis of the topographical distribution of afferent neurons from the thalamus and posterior tubercle/ventral tegmentum was emphasised. The main results show that inputs to the two striatopallidal systems originate from distinct dorsal thalamic nuclei, with dorsal and ventral striatopallidal afferent neurons favouring strongly the lateral/central and anterior thalamic nuclei, respectively. However, afferent neuron distribution in the dorsal thalamus does not differ in the rostrocaudal axis of the brain. Afferent neurons from the posterior tubercle and ventral tegmentum, on the other hand, are organised topographically along the rostrocaudal axis. About 85 % of afferent neurons to the dorsal striatopallidal system are located rostrally in the posterior tubercle, while 75 % of afferent neurons to the ventral striatopallidal system are found more caudally in the ventral tegmentum. This difference is statistically significant and confirms the presence of distinct mesostriatal pathways in an amphibian. These findings demonstrate that an amphibian brain displays striatopallidal systems integrating parallel streams of sensory information potentially under the influence of distinct ascending mesostriatal pathways. PMID:23881295

Ramsay, Zachary J; Laberge, Frédéric

2014-11-01

239

Inhibition of ionic transport and ATPase activities by serotonin analogues in the isolated toad lens.  

Science.gov (United States)

The effects of serotonin and five other indoles were tested on the electrical parameters and ionic transport in the isolated toad lens. Serotonin, tryptophan and 5-hydroxy-L-tryptophan did not affect the electrical parameters of the lens at concentrations as high as 1 mM. Tryptamine, 5-methyltryptamine and 5-methoxytryptamine had dual effects: 1 mM in the posterior bathing solution depressed the potential difference of the posterior face of the lens, which resulted in an increase in the translenticular potential difference and short-circuit current; 1 mM in the anterior solution (in contact with the lens epithelium) produced a quick and pronounced reduction of the potential difference of the anterior face. This resulted in a 90-100% decline of the translenticular short-circuit current. Serotonin and tryptamine were then tested for their effect on the ATPases of lens epithelium. Both amines inhibited the enzymes with tryptamine at 5 mM completely inhibiting all ATPase activity. Since tryptophan is transported from the aqueous humor into the lens and may be converted by lens enzymes to serotonin and tryptamine, these findings may have physiological implications in cataractogenesis. PMID:6252964

Candia, O A; Lanzetta, P A; Alvarez, L J; Gaines, W

1980-11-01

240

Fast and slow voltage modulation of apical Cl- permeability in toad skin at high [K+  

Directory of Open Access Journals (Sweden)

Full Text Available The influence of voltage on the conductance of toad skin was studied to identify the time course of the activation/deactivation dynamics of voltage-dependent Cl- channels located in the apical membrane of mitochondrion-rich cells in this tissue. Positive apical voltage induced an important conductance inhibition which took a few seconds to fully develop and was instantaneously released by pulse inversion to negative voltage, indicating a short-duration memory of the inhibiting factors. Sinusoidal stimulation at 23.4 mM [Cl-] showed hysteresis in the current versus voltage curves, even at very low frequency, suggesting that the rate of voltage application was also relevant for the inhibition/releasing effect to develop. We conclude that the voltage modulation of apical Cl- permeability is essentially a fast process and the apparent slow components of activation/deactivation obtained in the whole skin are a consequence of a gradual voltage build-up across the apical membrane due to voltage sharing between apical and basolateral membranes

Procopio J.

1997-01-01

 
 
 
 
241

Fast and slow voltage modulation of apical Cl- permeability in toad skin at high [K+  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The influence of voltage on the conductance of toad skin was studied to identify the time course of the activation/deactivation dynamics of voltage-dependent Cl- channels located in the apical membrane of mitochondrion-rich cells in this tissue. Positive apical voltage induced an important conductan [...] ce inhibition which took a few seconds to fully develop and was instantaneously released by pulse inversion to negative voltage, indicating a short-duration memory of the inhibiting factors. Sinusoidal stimulation at 23.4 mM [Cl-] showed hysteresis in the current versus voltage curves, even at very low frequency, suggesting that the rate of voltage application was also relevant for the inhibition/releasing effect to develop. We conclude that the voltage modulation of apical Cl- permeability is essentially a fast process and the apparent slow components of activation/deactivation obtained in the whole skin are a consequence of a gradual voltage build-up across the apical membrane due to voltage sharing between apical and basolateral membranes

J., Procopio.

1033-10-01

242

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english In anurans, changes in ambient temperature influence body temperature and, therefore, energy consumption. These changes ultimately affect energy supply and, consequently, heart rate (HR). Typically, anurans living in different thermal environments have different thermal sensitivities, and these cann [...] ot be distinguished by changes in HR. We hypothesized that Rhinella jimi (a toad from a xeric environment that lives in a wide range of temperatures) would have a lower thermal sensitivity regarding cardiac control than R. icterica (originally from a tropical forest environment with a more restricted range of ambient temperatures). Thermal sensitivity was assessed by comparing animals housed at 15° and 25°C. Cardiac control was estimated by heart rate variability (HRV) and heart rate complexity (HRC). Differences in HRV between the two temperatures were not significant (P=0.214 for R. icterica and P=0.328 for R. jimi), whereas HRC differences were. All specimens but one R. jimi had a lower HRC at 15°C (all P

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

2015-01-01

243

Developmental toxicity and risk assessment of nonylphenol to the South American toad, Rhinella arenarum.  

Science.gov (United States)

The toxicity of Nonylphenol, an emerging pollutant, on the common South American toad Rhinella arenarum was stage and time dependent, thus Median Lethal Concentrations (LC50) for acute (96h), short-term chronic (168h) and chronic exposure (336h) were 1.06; 0.96 and 0.17mgNP/L from embryonic period (S.4), whereas for exposure from larvae (S.25), LC50 remained constant at 0.37mgNP/L from 96h to 168h, decreasing to 0.11mgNP/L at 336h. NOEC-168h for exposure from embryos was 0.025mgNP/L. The Teratogenic Potential (NOEC-lethality/NOEC-sublethal effects) was 23 times higher than the threshold value, indicating a high risk for embryos to be malformed in absence of significant lethality and representing a threat for the species conservation. By comparing with other amphibians, the early development of R. arenarum was very sensitive to NP. The results highlight the relevance of extending the exposure time and look for the most sensitive stage in order to perform the bioassays for conservation purposes. PMID:25195099

Mariel, Aronzon Carolina; Alejandra, Babay Paola; Silvia, Pérez Coll Cristina

2014-09-01

244

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

Scientific Electronic Library Online (English)

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

Ulisses, Caramaschi.

2012-08-01

245

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

Directory of Open Access Journals (Sweden)

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

Ulisses Caramaschi

2012-08-01

246

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-08-31

247

Two new species of Oswaldocruzia (Nematoda: Trichostrongylina: Molineoidea) parasites of the cane toad Rhinella marina (Amphibia: Anura) from Peru.  

Science.gov (United States)

Two new species of Oswaldocruzia, O. manuensis sp. nov., and O. urubambaensis sp. nov. are described and illustrated from Peru, these are parasites of the cane toad Rhinella marina. O. manuensis is characterized by having cervical alae which are not well developed, ridges without chitinous supports, caudal bursa type II and branches of fork of dissimilar length. O. urubambaensis is characterized by a caudal bursa of type I, ridges with chitinous supports, a thin cephalic vesicle and origin of rays 9 in tip of the dorsal trunk. PMID:23377910

Guerrero, Ricardo

2013-03-01

248

Energetics of sodium transport in the urinary bladder of the toad. Effect of aldosterone and sodium cyanide.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Experiments were designed to determine whether the stimulatory effect of aldosterone on sodium transport involves an increase in tissue ATP. Urinary bladders that were removed from toads presoaked in 0.6% saline for 48-72 h, mounted as sacs, and maintained in open circuit except for brief observation of short circuit current every 30 min responded to 100 nM aldosterone added to the serosal bath with an increase in short circuit current to 170% of control hemibladders, which plateaus at 2-3 h....

Cortas, N.; Abras, E.; Arnaout, M.; Mooradian, A.; Muakasah, S.

1984-01-01

249

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-03-01

250

Complete genome sequence of a common midwife toad virus-like ranavirus associated with mass mortalities in wild amphibians in the Netherlands.  

Science.gov (United States)

A ranavirus associated with mass mortalities in wild water frogs (Pelophylax spp.) and other amphibians in the Netherlands since 2010 was isolated, and its complete genome sequence was determined. The virus has a genome of 107,772 bp and shows 96.5% sequence identity with the common midwife toad virus from Spain. PMID:25540340

van Beurden, Steven J; Hughes, Joseph; Saucedo, Bernardo; Rijks, Jolianne; Kik, Marja; Haenen, Olga L M; Engelsma, Marc Y; Gröne, Andrea; Verheije, M Helene; Wilkie, Gavin

2014-01-01

251

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

Science.gov (United States)

Parasites that are carried by invasive species can infect native taxa, with devastating consequences. In Australia, invading cane toads (Rhinella marina) carry lungworm parasites (Rhabdias pseudosphaerocephala) that (based on previous laboratory studies) can infect native treefrogs (Litoria caerulea and L. splendida). To assess the potential of parasite transmission from the invader to the native species (and from one infected native frog to another), we used surveys and radiotelemetry to quantify anuran microhabitat use, and proximity to other anurans, in two sites in tropical Australia. Unsurprisingly, treefrogs spent much of their time off the ground (especially by day, and in undisturbed forests) but terrestrial activity was common at night (especially in anthropogenically modified habitats). Microhabitat overlap between cane toads and frogs was generally low, except at night in disturbed areas, whereas overlap between the two frog species was high. The situations of highest overlap, and hence with the greatest danger of parasite transmission, involve aggregations of frogs within crevices by day, and use of open ground by all three anuran species at night. Overall, microhabitat divergence between toads and frogs should reduce, but not eliminate, the transmission of lungworms from invasive toads to vulnerable native frogs. PMID:25188421

Pizzatto, Lígia; Both, Camila; Shine, Richard

2014-01-01

252

76 FR 41808 - Draft Environmental Impact Statement and Draft Habitat Conservation Plan for Oncor Electric...  

Science.gov (United States)

...americanus), Houston toad (Bufo houstonensis), whooping crane (Grus americana), golden-cheeked warbler (Dendroica chrysoparia...Construction activities covered for new facilities include new overhead transmission and distribution lines, new support...

2011-07-15

253

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

CERN Document Server

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

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

2006-01-01

254

Acute toxic effects of cadmium in larvae of the green toad, pseudepidalea variabilis (pallas, 1769) (amphibia: anura).  

Science.gov (United States)

The environmental impact of cadmium use and its accumulation in nature have increased to alarming levels. This study aimed to morphologically and histologically investigate the acute toxic effects of cadmium on green toad, Pseudepidalea variabilis (Pallas, 1769) larvae. Embryos were obtained from specimens collected in amplexus from nature and kept under laboratory conditions until stage 26, when they were exposed to cadmium (0, 1, 5, 10, 25, and 50 Lig L?¹) for 96 h. The LC?? LC??, and LC?? values of cadmium were calculated to be 26.98, 35.35, and 46.31 Lig L?¹, respectively. Our results showed that cadmium had a negative effect on the body size of P. variabilis larvae (over 1 ng L?¹). Histological examination detected a fusion of gill lamellae, liver haemorrhage, oedema in the abdominal cavity, and deformations of pronephric tubules (over 10 ng L?¹). Our findings suggest that the green toad was sensitive to the cadmium treatment, with LC?? values lower than those reported by other studies. Thus, this species could be considered a reliable indicator species of environmental stress in aquatic ecosystem. PMID:25222576

Gürkan, Mert; Cetin, Ay?e; Hayretda?, Sibel

2014-09-01

255

Salida de campo a Santo Domingo de Silos, en Burgos, el 13 de septiembre de 1953  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Field trip to Santo Domingo de Silos, at Burgos, the 13th of September of 1953, of which there were noted observations about the following amphibians: Alytes sp. (Midwife Toad), Bufo bufo (Common Toad, refered as B.vulgaris by the author), Hyla sp. (Tree Frog), Lissotriton vulgaris (Smooth Newt), Rana sp. (Iberian), Salamandra salamandra (Fire Salamander, also refered as S.maculosa by the author) and Triturus cristatus (Great Crested Newt), the following reptiles: Acanthodactylus erythrurus (...

Valverde Go?mez, Jose? Antonio

2008-01-01

256

Locomotion and survival of two sympatric larval anurans, Bufo gargarizans (Anura: Bufonidae) and Rana zhenhaiensis (Anura: Ranidae), after partial tail loss  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Tadpoles of two sympatric anurans, Bufo gargarizans Cantor, 1842 and Rana zhenhaiensis Ye, Fei & Matsui, 1995, were used as model organisms to examine the effects of different levels of tail loss on swimming performance and survival. On average, B. gargarizans tadpoles were shorter and had smaller t [...] ails and body mass than R. zhenhaiensis. After 75% tail loss, the survival rate of experimental and control B. gargarizans tadpoles, and of experimental tadpoles of the two species, differed significantly; the number of tadpoles surviving a complete impairment of their swimming ability did not differ between B. gargarizans and R. zhenhaiensis. After 50% tail loss, the swimming performance (swimming speed, maximum distance and number of stops) of the two species was significantly affected. However, the adverse influence of tail loss on the swimming speed of B. gargarizans tadpoles was greater compared to R. zhenhaiensis tadpoles. Our data indicates that a 50% tail loss results in swimming costs for B. gargarizans and R. zhenhaiensis tadpoles, and that 75% tail loss decreases the survival rate of B. gargarizans tadpoles. Therefore, we conclude that tadpoles of different species and with the same degree of tail loss use distinctive strategies to improve individual fitness in the face of predator pressure.

Guo-Hua, Ding; Zhi-Hua, Lin; Li-Hua, Zhao.

2014-08-01

257

Delimiting genetic units in Neotropical toads under incomplete lineage sorting and hybridization  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Delimiting genetic units is useful to enhance taxonomic discovery and is often the first step toward understanding evolutionary mechanisms generating diversification. The six species within the Rhinella crucifer group of toads were defined under morphological criteria alone. Previous data suggest limited correspondence of these species to mitochondrial lineages, and morphological intergradation at transitions between forms suggests hybridization. Here we extensively sampled populations throughout the geographic distribution of the group and analyzed mitochondrial and nuclear sequence data to delimit genetic units using tree–based and allele frequency–based approaches. Results These approaches yielded complementary results, with allele frequency-based methods performing unexpectedly well given the limited number of loci examined. Both mitochondrial and nuclear markers supported a genetic structure of five units within the group, with three of the inferred units distributed within its main range, while two other units occur in separate isolates. The inferred units are mostly discordant with currently described forms: unequivocal association exists for only two of the six species in the group. Genetic evidence for hybridization exists for two pairs of units, with clear cyto–nuclear allele mixing observed in one case. Conclusions Our results confirmed that current taxonomy does not represent evolutionary units in the Rhinella crucifer group. Correspondence between genetically distinguishable units and the currently recognized species is only possible for Rhinella henseli and R. inopina. The recognition of other species relies on the reassessment of the geographic range of R. crucifer, the examination of the type series of R. ornata for hybrids, and on the use of additional markers to verify the genetic distinctiveness of R. abei. We state that R. pombali should not remain a valid species since its description appears to be based on hybrids, and that the name R. pombali should be considered a synonym of both R. crucifer and R. ornata. The fifth inferred but undescribed genetic unit may represent a new species. Our results underscore the potential of the R. crucifer species group to contribute to a better understanding of diversification processes and hybridization patterns in the Neotropics, and provide the basis for future evolutionary and taxonomic studies.

Thomé Maria Tereza C

2012-12-01

258

Fertilization and development of eggs of the South African clawed toad, Xenopus laevis, on sounding rockets in space.  

Science.gov (United States)

Egg rotation and centrifugation experiments strongly suggest a role for gravity in the determination of the spatial structure of amphibian embryos. Decisive experiments can only be made in Space. Eggs of Xenopus laevis, the South African clawed toad, were the first vertebrate eggs which were successfully fertilized on Sounding Rockets in Space. Unfixed, newly fertilized eggs survived reentry, and a reasonable number showed a seemingly normal gastrulation but died between gastrulation and neurulation. Only a few reached the larval stage, but these developed abnormally. In the future, we intend to test whether this abnormal morphogenesis is due to reentry perturbations, or due to a real microgravity effect, through perturbation of the reinitiation of meiosis and other processes, or started by later sperm penetration. PMID:11536956

Ubbels, G A; Berendsen, W; Kerkvliet, S; Narraway, J

1992-01-01

259

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

Science.gov (United States)

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

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

2012-07-01

260

Experimental and theory study of the system performance of TOAD using for demultiplexing in 160Gb/s OTDM transmission system  

Science.gov (United States)

In this paper, experimental and theoretical investigations of TOAD system performance are implemented. 80Gb/s to 10Gb/s all-optical demultiplexing by the TOAD is demonstrated successfully. Based on the travelling wave model, the non-ideal problems encountered in the experiment are analyzed. The results show the position of SOA is no need to be strictly placed beside the loop midpoint, due to the switching window can be periodically generated with asymmetry values of SOA, and the position of switching window can be adjusted by varying the temporal deviation between counter-propagation signals. Furthermore, the unperfected coupling ratio and the synchronization jitter between the signal and control are crucial limits for the demultiplexing application in 160Gb/s OTDM system.

Lu, Dan; Jia, Nan; Zhong, Kang-ping; Chen, Ming; Li, Tang-jun; Jian, Shui-sheng

2009-11-01

 
 
 
 
261

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

Directory of Open Access Journals (Sweden)

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

Bossuyt Franky

2009-06-01

262

The complete mitochondrial genome of the color changeable toad-headed agama, Phrynocephalus versicolor (Reptilia, Squamata, Agamidae).  

Science.gov (United States)

Abstract The complete mitochondrial genome sequence of color changeable toad-headed agama, Phrynocephalus versicolor, was determined using polymerase chain reaction (PCR), long-and-accurate PCR and directly sequencing by primer walking. The entire mitochondrial genome of P. versicolor was 16,429?bp in length, the accession was KJ749841 and the content of A, T, C, and G were 36.1%, 26.5%, 24.9% and 12.5%, respectively, which was similar to most vertebrate. The complete mitochondrial genome of P. versicolor contain 13 protein-coding genes, 2 rRNA genes, 23 tRNA genes, plus one control region and was similar to those of other Phrynocephalus sand lizards in gene arrangement and composition, except that tRNA-Phe and tRNA-Pro were exchanged and tRNA-Phe had two copies. The control region comprised three parts, one between tRNA-Thr and tRNA-Phe, a second between tRNA-Pro and tRNA-Phe, and a third between tRNA-Phe and 12S RNA. The complete mitochondrial genome of P. versicolor provided fundamental data for resolving phylogenetic relationship problems related to Agaimidae and genus Phrynocephalus. PMID:24989048

Song, Sen; Li, Donghai; Zhang, Caihong; Jiang, Kaiju; Zhang, Dandan; Chang, Cheng

2014-07-01

263

Calcium reduces the sodium permeability of luminal membrane vesicles from toad bladder. Studies using a fast-reaction apparatus  

International Nuclear Information System (INIS)

Regulation of the sodium permeability of the luminal membrane is the major mechanism by which the net rate of sodium transport across tight epithelia is varied. Previous evidence has suggested that the permeability of the luminal membrane might be regulated by changes in intracellular sodium or calcium activities. To test this directly, we isolated a fraction of the plasma membrane from the toad urinary bladder, which contains a fast, amiloride-sensitive sodium flux with characteristics similar to those of the native luminal membrane. Using a flow-quench apparatus to measure the initial rate of sodium efflux from these vesicles in the millisecond time range, we have demonstrated that the isotope exchange permeability of these vesicles is very sensitive to calcium. Calcium reduces the sodium permeability, and the half-maximal inhibitory concentration is 0.5 microM, well within the range of calcium activity found in cells. Also, the permeability of the luminal membrane vesicles is little affected by the ambient sodium concentration. These results, when taken together with studies on whole tissue, suggest that cell calcium may be an important regulator of transepithelial sodium transport by its effect on luminal sodium permeability. The effect of cell sodium on permeability may be mediated by calcium rather than by sodium itself

264

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

Directory of Open Access Journals (Sweden)

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

Rodrigo B. Ferreira

2009-12-01

265

Liver histopathology in the cane toad, Rhinella marina (Amphibia: Bufonidae), induced by Ortleppascaris sp. larvae (Nematoda: Ascarididae).  

Science.gov (United States)

Exposure to parasites is considered to be an important factor in the development of many diseases and histopathologies which are the result of the parasite-host interaction. The present study evaluated the impact of natural infection by larvae of Ortleppascaris sp. (Nematoda: Ascaridida) in the liver of the cane toad Rhinella marina (Linnaeus, 1758). Larvae were encysted in nodules delimited by collagenous fibers and fibroblasts or freely within the hepatic parenchyma, provoking a clear response from the host. The histological examination of the liver revealed viable larvae in a number of different developmental stages, as well as cysts filled with amorphous material and cell residues and surrounded by dense fibrotic tissue. The infection of the liver by these larvae induces a significant increase in the area occupied by melanomacrophages and a reduction or deficit in the vascularization of the liver, hypertrophy of the hepatocytes, vacuolar bodies, and cytoplasmatic granules. Focal concentrations of inflammatory infiltrates were observed enclosing the unencapsulated early-stage larvae. These results indicate that infection by Ortleppascaris sp. induces severe physiological problems and histopathological lesions in the liver of R. marina . PMID:22989059

Silva, Jefferson P E; da Silva, Djane C B; Melo, Francisco T V; Giese, Elane G; Furtado, Adriano P; Santos, Jeannie N

2013-04-01

266

Expression of cell adhesion molecules in the normal and T3 blocked development of the tadpole's kidney of Bufo arenarum (Amphibian, Anuran, Bufonidae) / Expressão das moléculas de adesão celular no desenvolvimento normal e com a inibição do hormônio tireoidea do rim nas larvas do Bufo arenarum (Amphibia, Anura, Bufonidae)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Moléculas de adesão celular atuam como tradutores do ambiente extracelular para o citoesqueleto e o núcleo e, conseqüentemente, induzindo mudanças no padrão da expressão das proteínas estruturais. Neste estudo, observamos os efeitos da inibição do hormônio tireóidea (TH) e detenção da metamorfose na [...] expressão da E-caderina, ?- e ?- catenina no desenvolvimento do rim do Bufo arenarum. As moléculas de adesão celular durante o desenvolvimento têm uma expressão temporal e espacial seletiva, sugerindo um papel específico na nefrogênese. Com o propósito de estudar os mecanismos de controle da expressão das moléculas de adesão durante o desenvolvimento renal, bloqueou-se a metamorfose do B. arenarum com uma substancia goitrogênica que bloqueia a síntese de TH. A expressão da E-caderina nos tubos proximais é independente do controle da tireóide. Entretanto, o bloqueio da síntese de TH provoca uma sobre elevação da E-caderina nos dutos coletores, nos tubos distais e nos glomérulos. A expressão da ?- e ?-catenina nos dutos coletores, nos tubos distais, nos glomérulos e no mesênquima mesonéfrico é independente da TH. O bloqueio da TH causa uma sobre-regulação da ?- e ?-catenina nos tubos proximais. Em contraste com a E-caderina, a expressão da caderina desmossomal demogloína 1 (Dsg-1) é ausente no controle durante a metamorfose da fase larval dos rins e se expressa em algumas células intersticiais nas larvas tratadas com KClO4. De acordo com este trabalho, a expressão Dsg-1 é subregulada pela TH. Demonstramos que a expressão da E-caderina, Dsg-1, ?-catenina e ?-catenina são afetadas de forma diferencial pelos níveis de TH, sugerindo um dependência hormonal destas proteínas na metamorfose renal do B. arenarum. Abstract in english Cell adhesion molecules act as signal transducers from the extracellular environment to the cytoskeleton and the nucleus and consequently induce changes in the expression pattern of structural proteins. In this study, we showed the effect of thyroid hormone (TH) inhibition and arrest of metamorphosi [...] s on the expression of E-cadherin, ?-and ?-catenin in the developing kidney of Bufo arenarum. Cell adhesion molecules have selective temporal and spatial expression during development suggesting a specific role in nephrogenesis. In order to study mechanisms controlling the expression of adhesion molecules during renal development, we blocked the B. arenarum metamorphosis with a goitrogenic substance that blocks TH synthesis. E-cadherin expression in the proximal tubules is independent of thyroid control. However, the blockage of TH synthesis causes up-regulation of E-cadherin in the collecting ducts, the distal tubules and the glomeruli. The expression of ?-and ?-catenin in the collecting ducts, the distal tubules, the glomeruli and the mesonephric mesenchyme is independent of TH. TH blockage causes up-regulation of ?-and ?-catenin in the proximal tubules. In contrast to E-cadherin, the expression of the desmosomal cadherin desmoglein 1 (Dsg-1) is absent in the control of the larvae kidney during metamorphosis and is expressed in some interstitial cells in the KClO4 treated larvae. According to this work, the Dsg-1 expression is down-regulated by TH. We demonstrated that the expression of E-cadherin, Dsg-1, ?-catenin and ?-catenin are differentially affected by TH levels, suggesting a hormone-dependent role of these proteins in the B. arenarum renal metamorphosis.

MF., Izaguirre; MN., García-Sancho; LA., Miranda; J., Tomas; VH., Casco.

2008-08-01

267

Joint estimation of habitat dynamics and species interactions: disturbance reduces co-occurrence of non-native predators with an endangered toad  

Science.gov (United States)

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 for rigorously examining hypotheses about inter-species and species-habitat interactions. In contrast to previous methods that infer dynamic processes based on static patterns in occupancy, the approach we took allows the dynamic processes that determine species-species and species-habitat interactions to be directly estimated.

Miller, David A.W.; Brehme, Cheryl S.; Hines, James E.; Nichols, James D.; Fisher, Robert N.

2012-01-01

268

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

Science.gov (United States)

One hundred specimens of Rhinella marina , (Anura: Bufonidae) collected in St. George's parish, Grenada, from September 2010 to August 2011, were examined for the presence of ectoparasites and helminths. Ninety-five (95%) were parasitized by 1 or more parasite species. Nine species of parasites were found: 1 digenean, 2 acanthocephalans, 4 nematodes, 1 arthropod and 1 pentastome. The endoparasites represented 98.9% of the total number of parasite specimens collected. Grenada represents a new locality record for Mesocoelium monas, Raillietiella frenatus, Pseudoacanthacephalus sp., Aplectana sp., Physocephalus sp., Acanthacephala cystacanth, and Physalopteridae larvae. The digenean M. monas occurred with the highest prevalence of 82%, contrasting many studies of R. marina where nematodes dominate the parasite infracommunity. Female toads were found to have a significantly higher prevalence of Amblyomma dissimile than male toads. Only 2 parasites exhibited a significant difference between wet and dry season with Parapharyngodon grenadensis prevalence highest in the wet season and A. dissimile prevalence highest during the dry season. Additionally, A. dissimile was significantly more abundant during the dry season. PMID:24960037

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

2014-10-01

269

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

Science.gov (United States)

Recent issues surrounding captive amphibians are often nutritionally related problems, such as hypovitaminosis A. Although supplementation of frogs with vitamin A is a topic of investigation, the underlying issue is understanding vitamin A metabolism in amphibian species. To develop a range of "normal" vitamin A concentrations for captive amphibians, baseline vitamin A concentrations must be established in wild amphibian species. In this study, two species, Cuban tree frogs (Osteopilus septentrionalis; n = 59) and marine toads (Rhinella marina; n = 20) were collected from the wild as part of an invasive species control program at Zoo Miami, Miami, Florida. Serum, liver, and whole body samples were analyzed for vitamin A content. The Cuban tree frogs showed higher concentrations on average of vitamin A in serum (82.8 ppb), liver (248.3 IU/g), and whole body (5474.7 IU/kg) samples compared with marine toads (60.1 ppb; 105.3 IU/g; 940.7 IU/kg, respectively), but differences were not significant (P = 0.22). What can be considered "normal" values of vitamin A concentrations across different amphibian species requires further investigation. Although all amphibians collected in this study appeared healthy, a larger sample size of animals, with known health histories and diets, may provide stronger evidence of normal expectations. PMID:25632678

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

2014-12-01

270

Calcium release in skinned muscle fibres of the toad by transverse tubule depolarization or by direct stimulation.  

Science.gov (United States)

1. Skeletal muscle fibres from the toad were mechanically skinned under paraffin oil and then bathed in a potassium HDTA solution (HDTA: hexamethylenediamine-tetraacetate) which mimicked the ionic composition of the myoplasm. 2. Rapid transient contractions could be triggered by substitution of K+ with Na+ (with no change of anion), which should have virtually no direct effect on the electrical polarization of the sarcoplasmic reticulum (SR) membrane. Up to thirty or more contractions could be evoked by repeated substitutions if there was sufficient 'repriming' time (about 30 s) between them; these rapid contractions were analagous to potassium contractures in intact fibres. 3. When the SR was not heavily loaded, substitution of potassium HDTA with choline chloride also produced a rapid, brief contraction. 4. All treatments designed to 'inactivate' the voltage sensor in the T-system invariably abolished the rapid contractions. Thus, rapid contractions were absent if (i) the T-system was permanently depolarized by pre-soaking the muscle in a high potassium solution with ouabain before skinning, (ii) a fibre was split rather than skinned, (iii) the T-system was temporarily depolarized by Na+ substitution immediately before choline chloride substitution, or vice versa, (iv) a skinned fibre was briefly exposed to saponin (50 micrograms/ml) to selectively disrupt the T-system membrane or (v) the muscle was pre-soaked in a solution with 1 mM-EGTA and no Ca2+ or Mg2+ before skinning. In contrast to (v), if 10 mM-Mg2+ was present in the EGTA solution before skinning, rapid contractions could be elicited, presumably because the presence of Mg2+ prevented the inactivation of the T-system voltage sensor in low [Ca2+]. 5. These results unequivocally demonstrate that (a) the T-system reseals and repolarizes after mechanical skinning under oil and (b) the fast contractions are produced by activation of the voltage sensor in the T-system. 6. When the SR had been heavily loaded, choline chloride substitution (but not Na+ substitution) could also induce an unphysiological, slow contraction ('second component'). In total contrast to the fast contraction, this slow component was unaffected by any of the treatments (i-v) above, indicating that it did not depend on activation of the voltage sensor in the T-system but resulted from a direct action of choline chloride on the SR.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1696987

Lamb, G D; Stephenson, D G

1990-04-01

271

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

Science.gov (United States)

Non-invasive endocrine monitoring with minimally invasive biological samples, such as urine, is being used widely for conservation biology research on amphibians. Currently, it is unknown how closely urinary measurements correspond with the traditional serum hormone measurements. We compared urinary and serum concentrations of corticosterone (CORT) and testosterone (T) in adult male cane toads (Rhinella marina) using a standard capture and handling (short-term stressor) protocol. Free-living male cane toads were captured and sampled for baseline urine (0h) with a second urine sample taken at 0.5h and hourly between 1 and 8h. A single blood sample was collected from each toad after the final urine sampling and capture handling. The mean serum CORT concentration increased between 0 and 0.5h, reaching the highest level between 6 and 8h. The mean urinary CORT concentration increased with a lag-time of 1h and continued to increase up to 8h. The mean level of serum T decreased between 0 and 7h and increased between 7 and 8h. Mean urinary T concentration decreased with a lag-time of 0.5h. Urinary T levels did not change between 4 and 8h. Mean serum T levels reached 50% of the original 0h value at 1h while mean serum CORT levels reached 200% of the original 0h value within 0.5h. Mean urinary T levels reached 50% of the original 0h value within 3h while mean urinary CORT levels reached 200% of the original 0h value within 3h. The inter-individual variation in baseline serum and urinary CORT and T levels were highly comparable, suggesting that baseline urine sample provides a reliable indicator of the physiological status of the animal. Overall, the results have demonstrated that urine sampling and standard capture handling protocol provide reliable measures of baseline corticosterone and testosterone, as well as short-term stress hormone responses in amphibians. PMID:23851041

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

2013-09-15

272

Repeated thermal stressor causes chronic elevation of baseline corticosterone and suppresses the physiological endocrine sensitivity to acute stressor in the cane toad (Rhinella marina).  

Science.gov (United States)

Extreme environmental temperature could impact the physiology and ecology of animals. The stress endocrine axis provides necessary physiological stress response to acute (day-day) stressors. Presently, there are no empirical evidences showing that exposure to extreme thermal stressor could cause chronic stress in amphibians. This could also modulate the physiological endocrine sensitivity to acute stressors and have serious implications for stress coping in amphibians, particularly those living in fragmented and disease prone environments. We addressed this important question using the cane toad (Rhinella marina) model from its introduced range in Queensland, Australia. We quantified their physiological endocrine sensitivity to a standard acute (capture and handling) stressor after exposing the cane toads to thermal shock at 35°C for 30min daily for 34 days. Corticosterone (CORT) responses to the capture and handling protocol were measured on three sampling intervals (days 14, 24, and 34) to determine whether the physiological endocrine sensitivity was maintained or modulated over-time. Two control groups (C1 for baseline CORT measurement only and C2 acute handled only) and two temperature treatment groups (T1 received daily thermal shock up to day 14 only and a recovery phase of 20 days and T2 received thermal shock daily for 34 days). Results showed that baseline CORT levels remained high on day 14 (combined effect of capture, captivity and thermal stress) for both T1 and T2. Furthermore, baseline CORT levels decreased for T1 once the thermal shock was removed after day 14 and returned to baseline by day 29. On the contrary, baseline CORT levels kept on increasing for T2 over the 34 days of daily thermal shocks. Furthermore, the magnitudes of the acute CORT responses or physiological endocrine sensitivity were consistently high for both C1 and T1. However, acute CORT responses for T2 toads were dramatically reduced between days 24 and 34. These novel findings suggest that repeated exposure to extreme thermal stressor could cause chronic stress and consequently suppress the physiological endocrine sensitivity to acute stressors (e.g. pathogenic diseases) in amphibians. PMID:24679975

Narayan, Edward J; Hero, Jean-Marc

2014-04-01

273

Urinary corticosterone responses to capture and toe-clipping in the cane toad (Rhinella marina) indicate that toe-clipping is a stressor for amphibians.  

Science.gov (United States)

Toe-clipping, the removal of one or more toes, is a common method used to individually mark free-living animals. Whilst this method is widely used in studies of amphibians, the appropriateness of the method, and its potential detrimental effects have been the subject of debate. Here, we provide for the first time, evidence that toe-clipping is a stressor in a wild amphibian. We measured urinary corticosterone responses of male cane toads (Rhinella marina) to capture and handling only, and to toe-clipping under field conditions. Urinary testosterone concentrations and white blood cell proportions were also measured. Urinary corticosterone metabolite concentrations increased 6h after capture and handling only and remained high for 24h; corticosterone returned to baseline levels after 48 h and remained low at 72 h post capture and handling. Corticosterone concentrations in toads subjected to toe-clipping increased at 6h to significantly higher concentrations than after capture and handling only, then decreased more slowly than after capture and handling, and were still elevated (approximately double basal level) 72 h after toe-clipping. Testosterone did not change significantly after capture and handling only, whereas after toe-clipping testosterone decreased at 6h and remained low at 72 h. There were weak short-term effects of toe-clipping compared with capture and handling only on white blood cell proportions. We have clearly shown that toe-clipping is a distinctly stronger stressor than capture and handling alone. This indicates that there is an ethical cost of toe-clipping, and this should be considered when planning studies of amphibians. PMID:21945118

Narayan, Edward J; Molinia, Frank C; Kindermann, Christina; Cockrem, John F; Hero, Jean-Marc

2011-11-01

274

Excursión a Aranda de Duero (Burgos) el 7 de septiembre de 1953  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Trip to Aranda de Duero, at Burgos, the 7th of September of 1953, of which there were noted observations about the following amphibians: Bufo bufo (Common Toad, refered as B.vulgaris by the author), Hyla arborea (European Tree Frog), Pelophylax esculentus (Edible Frog, refered as Rana sculenta or R.esculenta ridibunda by the author), Salamandra salamandra (Fire Salamander) and Triturus marmoratus (Marbled Newt, refered as Molge marmorata by the author), the following reptiles: Acanthodactylus...

Valverde Go?mez, Jose? Antonio

2008-01-01

275

Test the Toad  

Science.gov (United States)

This game helps children develop concepts and fluency in addition and subtraction within 15. Students indicate the correct answer to a displayed problem by clicking on the appropriately numbered person in a number line. Audio and visual cues help reinforce counting on and back, as well as the meaning and effects of the operations. The resource includes links to printable worksheets and useful information and activities for teachers and parents.

2013-01-01

276

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

Directory of Open Access Journals (Sweden)

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

Fabrizio Li Vigni

2007-01-01

277

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

Directory of Open Access Journals (Sweden)

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

Schneider Horacio

2011-09-01

278

Complete mitochondrial genome of the desert toad-headed agama, Phrynocephalus przewalskii (Reptilia, Squamata, Agamidae), a novel gene organization in vertebrate mtDNA.  

Science.gov (United States)

Abstract The mitogenome of the desert toad-headed agama, Phrynocephalus przewalskii, was amplified using polymerase chain reaction (PCR), long-and-accurate PCR and directly sequenced by primer walking. The complete mitogenome was 16,892?bp in size and contained 13 protein-coding, 23 tRNA, and 2 rRNA genes, and 1 control region. The mitogenome of the P. przewalskii was similar to those of other Phrynocephalus sand lizards in gene arrangement and composition, except that tRNA-Phe and tRNA-Pro were exchanged and tRNA-Phe had two copies. The control region comprised three parts, one between tRNA-Thr and tRNA-Phe, a second between the two tRNA-Phe copies, and a third between tRNA-Pro and 12S RNA. The overall nucleotide composition of the H-strand was 36.3% A, 26.7% T, 12.5% G, 24.6% C. The complete mitogenome of P. przewalskii will contribute to understanding the evolution of the genus Phrynocephalus and the family Agamidae. PMID:24117191

Li, Donghai; Song, Sen; Chen, Tao; Zhang, Caihong; Chang, Cheng

2013-10-14

279

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

Science.gov (United States)

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

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

2014-10-01

280

Diet of the toad Rhinella icterica (Anura: Bufonidae) from Atlantic Forest Highlands of southeastern Brazil / Dieta do sapo Rhinella icterica (Anura: Bufonidae) em altitudes elevadas na Mata Atlântica do sudeste do Brasil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese No presente estudo apresentamos informações sobre o nicho trófico de uma espécie de anuro que reside em altitudes elevadas da Mata Atlântica. Descrevemos a dieta do sapo Rhinella icterica em altitudes acima de 2000 m em áreas de Campos de Altitude no Parque Nacional do Itatiaia. Encontramos 150 iten [...] s nos estômagos analisados de R. icterica, divididos em apenas cinco categorias de presa, além de vestígios da própria pele do anuro e restos vegetais. O índice de importância relativa indicou que besouros e formigas foram os itens mais importantes sendo que formigas representam 70% dos itens ingeridos. A amplitude de nicho trófico (B) foi de 1,81. O reduzido número de categorias alimentares, bem como o elevado número de formigas na dieta sugere que R. icterica apresente uma preferência por este item. Não encontramos nenhuma relação significativa entre as dimensões do anuro com as dimensões das presas. Concluímos que a população de R. icterica que habita os campos de altitude de Itatiaia alimentam-se de artrópodes, principalmente formigas e besouros. O alto consumo de presas com tamanho relativamente semelhante e pequeno como, por exemplo, formigas, impede uma relação esperada entre o tamanho do corpo do anuro ou o tamanho de sua mandíbula e tamanho e volume de presas. Abstract in english In this study, we present some information of the regarding throphic niche from the anuran toad Rhinella icterica living in high altitudes above 2000 m a.s.l. from a habitat of the Atlantic Forest Biome - the Altitude Fields in the Itatiaia National Park. We found 150 prey items in toad stomachs, be [...] longing to five prey types, as well as skin remains and some remains of plant material. The index of relative importance indicated that most important prey types were beetles and ants, these last composing 70% of the diet numerically and the trophic niche breadth (B) was 1.81. The relatively low diversity of prey types we recorded in the diet of R. icterica of Itatiaia and numerically dominated by ants suggests some preference for this item. We do not found significant relationship between the toad measurements with the preys' measurements. We concluded that R. icterica toads at the highlands of Itatiaia feeds on arthropods, mainly ants and coleopterans and that the high consumption of preys with relatively small and similar size as ants in the diet prevents an expected relationship among frog body or mouth size and prey volume and size.

Leandro Talione, Sabagh; Ana Maria Paulino Telles, Carvalho-e-Silva; Carlos Frederico Duarte, Rocha.

2012-12-01

 
 
 
 
281

[Histochemical study of glutamate dehydrogenase activity in the medulla, bulb and in the central cerebellar nuclei of various vertebrates].  

Science.gov (United States)

In this work we research into the GDH location of the spinal cord, in the medullar oblongata and in the central cerebellar nuclei of the rat, cat, dog, chicken, lizard (Lacerta lepida), and Toad (Bufo calamita). The GDH is located at the cytoplasm and at the neuronal prolongations, at oligodendrocytes cells, at Lecerta ependimary glial cells, and at the capillary walls. PMID:913996

Garcia-Segura, L M; Martinez-Rodriquez, R; Toledano, A

1977-01-01

282

Induction of micronuclei and nuclear abnormalities in tadpoles of the common toad (Rhinella arenarum) treated with the herbicides Liberty® and glufosinate-ammonium.  

Science.gov (United States)

The assessment of micronucleated erythrocytes (ME) in blood represents a widely used method for the detection of chromosomal damage by chemical agents, such as herbicides that may occur as water contaminants. We investigated the changes in some circulating blood-cell parameters of tadpoles of the common toad (Rhinella arenarum) that were exposed during 48 or 96 h to three sub-lethal concentrations (3.75, 7.5, and 15 mg/L) of a commercial formulation of a glufosinate-ammonium (GLA)-based herbicide (Liberty(®), LY(®)) as well as to the corresponding active ingredient GLA. The frequency of ME and other erythrocyte nuclear abnormalities (ENA, i.e., lobed nuclei, binucleates or segmented nuclei, kidney-shaped nuclei, notched nuclei, and picnotic nuclei) were evaluated and compared with positive (cyclophosphamide, CP, 40 mg/L) and negative (de-chlorinated tap water) controls. The results indicate that the exposure of R. arenarum tadpoles to LY(®) induces a concentration-dependent increase in ME frequency. The ENA frequency at 48 h was also significantly higher than that in the negative control group for all the chemicals assayed (CP, LY(®) and GLA) whereas at 96 h, increases in ENA over the negative control group were found only for CP and GLA (7.5 mg/L). Our study demonstrates that the commercial formulation of a GLA-based herbicide induces micronucleus formation in R. arenarum tadpoles, in contrast to the active ingredient. According to these results, the inert ingredients of the commercial formulation played an important role in the production of genotoxic damage in erythrocytes of amphibian tadpoles. PMID:24769302

Lajmanovich, Rafael C; Cabagna-Zenklusen, Mariana C; Attademo, Andrés M; Junges, Celina M; Peltzer, Paola M; Bassó, Agustín; Lorenzatti, Eduardo

2014-07-15

283

Effects of multiple chemical, physical, and biological stressors on the incidence and types of abnormalities observed in Bermuda's cane toads (Rhinella marina).  

Science.gov (United States)

The interactive effects of contaminants and ultraviolet light (UV)-exposure on the incidence and types of abnormalities observed were measured in newly metamorphosed cane toads (Rhinella marina) from four Bermuda ponds contaminated with petrochemicals and metals. Abnormalities were compared in toadlets that were field-collected, reared in predator exclusion cages, reared in laboratory microcosms exposed to control media or corresponding pond media, and reared in laboratory microcosms exposed to UV-light and control media or media from two ponds. Percent abnormal for field-collected, cage-reared, and microcosm-reared toadlets were equivalent per site and ranged between 14% and 63%. All treatments produced similar limb abnormalities but the percentage of hind versus forelimb defects was statistically greater only in field-collected toadlets. UV-exposed control media did not induce abnormalities in larvae exhibiting no maternal effect, and did not alter the types of abnormalities observed in larvae exhibiting a maternal or latent effect. Site media treatments without UV exposure induced significant cephalic and limb abnormalities, proved additive to the observed maternal/latent effect, and produced limb defects predominantly in forelimbs. Concurrent exposure to site media and UV-light induced similar types of abnormalities but a significantly higher percentage of hind limb abnormalities (68-89%) than exposure to site media alone (7-13%). Our results suggest that the types of abnormalities expressed were principally determined by direct and/or transgenerational contaminant exposure, but that UV-light exposure caused limb abnormalities to occur primarily in the hind limbs, mirroring field observations. Our field observations also suggest that ectromelia and brachydactyly in some field-collected specimens may be predator-induced. PMID:23526808

Bacon, Jamie P; Fort, Chelsea E; Todhunter, Brian; Mathis, Michael; Fort, Douglas J

2013-06-01

284

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

Directory of Open Access Journals (Sweden)

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

Giovanni Scillitani

2011-07-01

285

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

Directory of Open Access Journals (Sweden)

Full Text Available We studied the glycopatterns and ultrastructure of the extra-cellular matrix (ECM of the egg of the Apennine yellow-bellied toad Bombina pachypus, by light and electron microscopy in order to determine structure, chemical composition and function. Histochemical techniques in light microscopy included PAS and Alcian Blue pH 2.5 and 1.0, performed also after b-elimination. Lectin-binding was tested with nine lectins (AAA, ConA, DBA, HPA, LTA, PNA, SBA, UEA-I, WGA. An inner fertilization envelope (FE and five jelly layers (J1–J5 were observed, differing in histochemical staining, lectin binding and ultrastructure. Most glycans were O-linked, with many glucosamylated and fucosylated residues. The fertilization envelope presented a perivitelline space and a fertilization layer, with mostly neutral glycans. The jelly layers consisted of fibers and granules, whose number and orientation differed between layers. Fibers were densely packed in J1 and J4 layers, whereas a looser arrangement was observed in the other layers. Jelly-layer glycans were mostly acidic and particularly abundant in the J1 and J4 layers. In the J1, J2 and J5 layers, neutral, N-linked glycans were also observed. Mannosylated and/or glucosylated as well as galactosyl/galactosaminylated residues were more abundant in the outer layers. Many microorganisms were observed in the J5 layer. We believe that, apart from their functions in the fertilization process, acidic and fucosylated glycans could act as a barrier against pathogen penetration. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 2, pp. 306–316

Maria Mastrodonato

2011-07-01

286

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

Science.gov (United States)

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

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

2013-02-01

287

PCR detection of ranavirus in adult anurans from the Louisville Zoological Garden.  

Science.gov (United States)

Ranaviruses are known to cause mortality in a variety of anuran species and have the potential to significantly impact wild and captive frog populations. In this study, 16 captive frogs and toads from the Louisville Zoological Garden were examined for the presence of ranavirus; this group included 14 Cope's grey tree frogs (Hyla chrysoscelis), an American toad (Bufo americanus), and a southern toad (Bufo terrestris). All animals were wild caught and were evaluated via polymerase chain reaction (PCR), while animals that died were also assessed via histologic study to understand the role of ranaviral disease in these specimens. Of the animals that died, 82% were positive for ranavirus via PCR. Multiple swab samples collected over time from live tree frogs were positive for ranavirus via PCR. These findings reveal that ranaviral infection in captive adult anurans may occur without clinical signs or consistent histopathologic lesions. PMID:19746873

Driskell, Elizabeth A; Miller, Debra L; Swist, Shannon L; Gyimesi, Zoltan S

2009-09-01

288

Effects of osmolality and ionic strength on the mechanism of Ca2+ release in skinned skeletal muscle fibres of the toad.  

Science.gov (United States)

1. The effects of increased osmolality and ionic strength on the mechanism of Ca2+ release were examined in mechanically skinned skeletal muscle fibres of the toad at 23 degrees C. Ca2+ release was induced by depolarizing the transverse tubular (T-) system by ionic substitution. 2. Increasing the osmolality of the 'myoplasmic' solution about four times (to 955 mosmol/kg), by addition of 700 mM sucrose to the standard potassium (K-)HDTA solution (HDTA: hexamethylenediamine-tetraacetate), only depressed the depolarization-induced response by about 46%. Much of this decrease could be attributed to a reduction in the Ca(2+)-sensitivity of the contractile proteins at this high osmolality. 3. Addition of > 400 mM sucrose itself often induced substantial Ca2+ release and a transient tension response. This 'spontaneous' release was (a) greatly enhanced when the sarcoplasmic reticulum (SR) had been heavily loaded with Ca2+, (b) little affected by inactivation of the voltage sensors by prolonged or permanent depolarization of the T-system and (c) blocked by Ruthenium Red (10 microM). 4. When both the osmolality and ionic strength were increased, by increasing the K-HDTA concentration, the depolarization-induced force was greatly reduced (to 35% at 818 mosmol/kg and 5% at 1095 mosmol/kg). Most of this reduction could be directly attributed to the substantially reduced maximum force and Ca2+ sensitivity of the contractile apparatus. 5. The small amount of releasable Ca2+ remaining in the SR after a single depolarization in a high-HDTA solution with 1 mM EGTA (to chelate the released Ca2+), indicated that depolarization could still elicit massive Ca2+ release at high ionic strength and osmolality (at 1 mM free Mg2+). 6. In contrast, when the total Mg2+ and ATP concentrations were raised about threefold (free [Mg2+] increased 2.7-fold) along with the osmolality and ionic strength, the ability of depolarization to elicit Ca2+ release was greatly hindered. 7. Osmotic compression of the skinned fibres to their in situ diameter by addition of 4% polyvinylpyrrolidone (PVP-40), substantially potentiated the depolarization-induced force responses, due partly to an increase in the Ca(2+)-sensitivity of the contractile apparatus. 8. These results indicate how increased intracellular osmolality, ionic strength and [Mg2+] produce the transient contraction and subsequent inhibition of tetanic tension in intact muscle fibres exposed to hypertonic solutions. PMID:8229822

Lamb, G D; Stephenson, D G; Stienen, G J

1993-05-01

289

Lymph flux rates from various lymph sacs in the cane toad Rhinella marina: an experimental evaluation of the roles of compliance, skeletal muscles and the lungs in the movement of lymph.  

Science.gov (United States)

A new method for quantitatively determining lymph flux from various lymphatic sacs of an anuran, the cane toad, was developed. This method used the dye dilution principle of C(i)V(i)=C(f)V(f) following injection of Evans Blue into specific lymph sacs and measuring its appearance in the venous circulation. The apparent lymph volume was 57 ml kg(-1). The greatest rate of lymph return (0.5-0.8 ml kg(-1) min(-1)) and best linear fit of Evans Blue appearance in the circulation with time followed injections into the subvertebral lymph sac, which has direct connections to both the anterior and posterior pairs of lymphatic hearts. Rate of lymph flux from the pair of posterior lymph hearts was three times greater than the anterior pair. Rates of lymph flux were only influenced by injection volume in the crural lymph sacs, implicating lymph sac compliance as the source of the pressure for lymph movement from these sacs. Femoral lymph sac fluxes were decreased by 60% following ablation of the tendons of the sphincter ani cloacalis, abdominal crenators and piriformis. This supports a role for these muscles in generating the pressure for vertical lymph movement. Femoral lymph sac fluxes were also decreased by 70% by the insertion of a coil in the subvertebral lymph sac, preventing normal compression and expansion of this sac by the lungs. This supports a role for lung ventilation in generating the pressure for vertical movement of lymph. Contrary to previous hypotheses, fluxes from the brachial sac were not influenced by insertion of the coil into the subvertebral sac. A haemorrhage equivalent to 50% of the blood volume did not change lymph flux rates from the femoral lymph sacs. These data provide the first experimental evidence that actual lymph fluxes in the cane toad Rhinella marina depend on lymph sac compliance, contraction of specific skeletal muscles and lung ventilation to move lymph laterally and vertically to the dorsally located lymphatic hearts. PMID:20802118

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

2010-09-15

290

Feleucin-BO1: A Novel Antimicrobial Non-Apeptide Amide from the Skin Secretion of the Toad, Bombina orientalis, and Design of a Potent Broad-Spectrum Synthetic Analogue, Feleucin-K3.  

Science.gov (United States)

Feleucins-BV1 and -BV2 are recently described prototypes of a novel antimicrobial non-apeptide (AMP) family identified in the skin secretion of the bombinid toad, Bombina variegata. They are encoded on different precursors that also encode a novel bombinin. Here we describe the identification of feleucin-BO1 (FLGLLGSLLamide) which is co-encoded with a different novel bombinin, named feleucin precursor-associated bombinin (FPA-bombinin-BO), from the skin secretion of Bombina orientalis. Synthetic feleucin-BO1 displayed activity against a reference Gram-positive bacterium. Staphylococcus aureus (MIC 34 ?m) but was inactive (> 250 ?m) against the Gram-negative bacterium, Escherichia coli, and the yeast, Candida albicans. This pattern of activity was similar to that of the prototypes. Design and synthesis of a cationicity-enhanced analogue, feleucin-K3 (F-K3), in which the amino acid residues at positions 3 (G), 6 (G) and 7 (S) of feleucin-BO1 were substituted with Lys (K) residues, resulted in a peptide with significantly enhanced potency and spectrum of activity. The MICs of F-K3 against the reference micro-organisms were 7 ?m (S. aureus), 14 ?m (E. coli) and 7 ?m (C. albicans). These data indicate that the skin secretions of amphibians can continue to provide novel peptide templates for the rational design of analogues with possible therapeutic utility. PMID:25056849

Hou, Xiaojuan; Du, Qiang; Li, Renjie; Zhou, Mei; Wang, Hui; Wang, Lei; Guo, Can; Chen, Tianbao; Shaw, Chris

2015-03-01

291

Biosystematic Study of Anura in the Markazy Province of Central Iran  

Directory of Open Access Journals (Sweden)

Full Text Available Only recently Anuran fauna of Iran has been studied systematically. In order to study the biosystematics of Anuran in the Markazy Province, 122 specimens were collected from six stations during spring and summer 2004-2005. Samples were transferred alive to the zoology laboratory, identified and were preserved. The samples composed of the marsh frog, Rana ridibunda and the green toad, Bufo viridis. The phenetic studies between populations of the two species, 14 characteristics in frog and 17 characteristics in toad were measured. T-test analysis between sexes were significant in 12 characteristics for frogs and only one characteristic for toads (p<0.001. One way ANOVA between populations for each species were significant in 13 characteristics for frogs and 6 characteristics for toads (p<0.001. Difference between multivariate mean vectors confirmed in T2 Hotelling for populations and sexes of marsh frog (p<0.001. Length of foot and femur were discriminated distinct sexes based on discrimination analysis with 89% correct grouping for frogs and space between eyelids with 92% correct grouping for toads. Discrimination analysis between populations discriminated groups based on two functions with 78% correct grouping in frogs and 88% correct grouping in toads. Cluster analysis based on centroids grouped populations resulted from geographical and ecological conditions.

Hezaveh Nasim

2007-01-01

292

Toads Give You Warts--Not!  

Science.gov (United States)

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

Tomasek, Terry; Matthews, Catherine E.

2008-01-01

293

Pesticide has asymmetric effects on two tadpole species across density gradient.  

Science.gov (United States)

Northern leopard frogs (Rana pipiens) have been disappearing throughout their range. The causes for extirpations have been elusive, although habitat alteration appears to be a major factor. Pesticides have been implicated in declines in western amphibians, but no mechanism has been identified. We tested the hypothesis that leopard frog tadpoles would be eliminated from insecticide-exposed ponds when they were less abundant than a competitor (American toads, Bufo americanus) by manipulating toad and leopard frog density (16, 50, or 150 of each species) with or without the insecticide carbaryl. Insecticide exposure did not interact with density on either species, indicating that contaminant effects were similar despite drastic differences in competition. The survival of both species decreased with increasing conspecific density, but not heterospecific density. Leopard frogs produced more metamorphs at intermediate densities, whereas toads produced more metamorphs at high density. Leopard frog mass at and time to metamorphosis responded negatively to density. Carbaryl did not affect leopard frog survival but positively affected mass at and time to metamorphosis. In contrast, toad survival was reduced after exposure, but mass at metamorphosis was greater. Pesticide-induced survival reductions may not affect population size if reductions are slight (as in toads, whose fitness may be compensated by increased mass). Management strategies aimed at ameliorating the effects of carbaryl in systems with these two species may not need to consider density. PMID:21298710

Distel, Christopher A; Boone, Michelle D

2011-03-01

294

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

Directory of Open Access Journals (Sweden)

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

Gianpaolo Montinaro

2007-01-01

295

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-07-01

296

Activity of sarafotoxin/endothelin peptides in the heart and brain of lower vertebrates.  

Science.gov (United States)

The effects of sarafotoxin-b (SRTX-b) and endothelin-1 (ET-1) were tested in the fish tilapia (Ore niloticus x O. aureus hybrids) and torpedo (Torpedo ocellata), the toad (Bufo viridis), the agama lizard (Agama stellio) and water snake (Natrix tessellata). In isolated heart preparations of the fish and agama, peptide doses of 0.05-0.5 micrograms/ml induced positive inotropic effects, reduction of the contraction rate and arrhythmia, leading to cardiac arrest. In the toad, a negative inotropic effect and a reduction of the contraction rate were observed, whereas the water snake was hardly affected by either SRTX-b or ET-1. In the agama, an i.v. injection of 15 micrograms of SRTX-b caused changes in the ECG, culminating in A-V block that led to cardiac arrest, while in the toad an injection of 45 micrograms induced only transient disturbances in the ECG. Binding studies with 125I-SRTX-b revealed specific binding sites for SRTX-b and ET-1 in the heart and brain preparations of fish (tilapia and torpedo) and agama, whereas no specific binding could be demonstrated in the toad or in the snake. These results suggest that most vertebrates tested are sensitive to SRTX/ET, while the snake may possess receptors that are of a different structure. PMID:1626325

Zigdon-Arad, T; Bdolah, A; Kochva, E; Wollberg, Z

1992-04-01

297

Influenza em animais heterotérmicos Influenza in heterothermics  

Directory of Open Access Journals (Sweden)

Full Text Available O objetivo foi pesquisar Ortomyxovirus em animais heterotérmicos. Coletou-se sangue de serpentes dos gêneros Bothrops e Crotalus e de sapo e rãs dos gêneros Bufo e Rana, para a detecção dos receptores de hemácias e anticorpos específicos, ao vírus influenza, pelos testes de hemaglutinação e inibição da hemaglutinação, respectivamente. Pelo teste de hemaglutinação, verificou-se que serpentes e sapos em cativeiro apresentaram receptores em suas hemácias para o vírus influenza, humano e eqüino do tipo A e tipo B. O mesmo ocorreu com serpentes recém chegadas. Quanto ao teste de inibição da hemaglutinação dos soros dos répteis observou-se títulos protetores de anticorpos aos vírus influenza tipo A (origens humana e eqüina e tipo B. Com soro de sapo não se observou reação de inibição da hemaglutinação porém, 83,3% das rãs obtiveram médias de 40UIH para algumas cepas. Conclui-se que animais heterotérmicos podem oferecer condições de hospedeiros aos vírus influenza, assim como susceptibilidade à infecção.The objective was to study Orthomyxovirus in heterothermic animals. Blood samples from snakes (genus Bothrops and Crotalus and from toads and frogs (genus Bufo and Rana were collected to evaluate the red cell receptors and antibodies specific to influenza virus by the hemagglutination and hemagglutination inhibition tests, respectively. Both snakes and toads kept in captivity presented receptors in their red cells and antibodies specific to either influenza virus type A (human and equine origin or influenza type B. The same was observed with recently captured snakes. Concerning the influenza hemagglutination inhibition antibodies protective levels were observed in the reptiles' serum, against influenza type A and type B. Unlike the toads, 83.3% of the frogs presented mean levels of Ab 40HIU for some influenza strains. It was concluded that heterothermic animals could offer host conditions to the influenza virus and also susceptibility to the infection.

Dalva Assunção Portari Mancini

2004-06-01

298

Influenza em animais heterotérmicos / Influenza in heterothermics  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O objetivo foi pesquisar Ortomyxovirus em animais heterotérmicos. Coletou-se sangue de serpentes dos gêneros Bothrops e Crotalus e de sapo e rãs dos gêneros Bufo e Rana, para a detecção dos receptores de hemácias e anticorpos específicos, ao vírus influenza, pelos testes de hemaglutinação e inibição [...] da hemaglutinação, respectivamente. Pelo teste de hemaglutinação, verificou-se que serpentes e sapos em cativeiro apresentaram receptores em suas hemácias para o vírus influenza, humano e eqüino do tipo A e tipo B. O mesmo ocorreu com serpentes recém chegadas. Quanto ao teste de inibição da hemaglutinação dos soros dos répteis observou-se títulos protetores de anticorpos aos vírus influenza tipo A (origens humana e eqüina) e tipo B. Com soro de sapo não se observou reação de inibição da hemaglutinação porém, 83,3% das rãs obtiveram médias de 40UIH para algumas cepas. Conclui-se que animais heterotérmicos podem oferecer condições de hospedeiros aos vírus influenza, assim como susceptibilidade à infecção. Abstract in english The objective was to study Orthomyxovirus in heterothermic animals. Blood samples from snakes (genus Bothrops and Crotalus) and from toads and frogs (genus Bufo and Rana) were collected to evaluate the red cell receptors and antibodies specific to influenza virus by the hemagglutination and hemagglu [...] tination inhibition tests, respectively. Both snakes and toads kept in captivity presented receptors in their red cells and antibodies specific to either influenza virus type A (human and equine origin) or influenza type B. The same was observed with recently captured snakes. Concerning the influenza hemagglutination inhibition antibodies protective levels were observed in the reptiles' serum, against influenza type A and type B. Unlike the toads, 83.3% of the frogs presented mean levels of Ab 40HIU for some influenza strains. It was concluded that heterothermic animals could offer host conditions to the influenza virus and also susceptibility to the infection.

Dalva Assunção Portari, Mancini; Rita Maria Zucatelli, Mendonça; Aurora Marques, Cianciarullo; Leonardo Setsuo, Kobashi; Hermínio Gomes, Trindade; Wilson, Fernandes; José Ricardo, Pinto.

2004-06-01

299

Effects of chlorinated solvents on four species of North American amphibians.  

Science.gov (United States)

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. PMID:15346783

McDaniel, T V; Martin, P A; Ross, N; Brown, S; Lesage, S; Pauli, B D

2004-07-01

300

Suitability of golf course ponds for amphibian metamorphosis when bullfrogs are removed.  

Science.gov (United States)

Managing areas designed for human recreation so that they are compatible with natural amphibian populations can reduce the negative impacts of habitat destruction. We examined the potential for amphibians to complete larval development in golf course ponds in the presence or absence of overwintered bullfrog tadpoles (Rana catesbeiana), which are frequently found in permanent, human-made ponds. We reared larval American toads (Bufo americanus), southern leopard frogs (R. sphenocephala), and spotted salamanders (Ambystoma maculatum) with 0 or 5 overwintered bullfrog tadpoles in field enclosures located in ponds on golf courses or in experimental wetlands at a reference site. Survival to metamorphosis of American toads, southern leopard frogs, and spotted salamanders was greater in ponds on golf courses than at reference sites. We attributed this increased survival to low abundance of insect predators in golf course ponds. The presence of overwintered bullfrogs, however, reduced the survival of American toads, southern leopard frogs, and spotted salamanders reared in golf course ponds, indicating that the suitability of the aquatic habitats for these species partly depended on the biotic community present. Our results suggest that ponds in human recreational areas should be managed by maintaining intermediate hydroperiods, which will reduce the presence of bullfrog tadpoles and predators, such as fish, and which may allow native amphibian assemblages to flourish. PMID:18254862

Boone, Michelle D; Semlitsch, Raymond D; Mosby, Cory

2008-02-01

 
 
 
 
301

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

International Nuclear Information System (INIS)

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

302

Sodium channels in membrane vesicles from cultured toad bladder cells  

International Nuclear Information System (INIS)

Electrical potential-driven 22Na+ fluxes were measured in membrane vesicles prepared from TBM-18(cl23) cells (a clone of the established cell line TB-M). Fifty to seventy percent of the tracer uptake in vesicles derived from cells that were cultivated on a porous support were blocked by the diuretic amiloride. The amiloride inhibition constant was +-specific channels. Vesicles prepared from cells that were not grown on a porous support exhibited much smaller amiloride-sensitive fluxes. Two Ca2+-dependent processes that down-regulated the channel conductance and were previously identified in native epithelia were found in the cultured cells as well. Vesicles isolated from cells that were preincubated with 5 x 10-7 M aldosterone for 16-20 h exhibited higher amiloride-sensitive conductance than vesicles derived from control, steroid-depleted cells. Thus membrane derived from TBM-18(cl23) cells can be used to characterize the epithelial Na+ channel and its hormonal regulation

303

Bufo arenarum Hensel, 1867 (Amphibia: Anura: Bufonidae) para el Noroeste del Uruguay  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Uruguay, Departamento de Paysandú. Paysandú. Puente Internacional, Comisión Administradora del Río Uruguay. 17 de mayo de 1995. Col: C. Ríos. Colección Zoología Vertebrados de la Facultad de Ciencias (Montevideo, Uruguay) ZVCB 2758 (macho).Departamento de Salto. Salto. Club de Remeros. 27 de febrero de 1997. Col: A. Olmos ZVCB 3459 (hembra).

Olmos, Alejandro; Maneyro, Rau?l

1998-01-01

304

Tazonomy of Toxoplasma.  

Science.gov (United States)

After reviewing reports of the hosts, structure and life cycle of Toxoplasma, the genus is placed in the apicomplexan family Eimeriidae and the folllowing 7 species are recognized: Toxoplasma gondii (Nicolle & Manceaux) (type species) from about 200 species of mammals and birds, with oocysts in felids; Toxoplasma alencari (Da Costa & Pereira) from the frog Leptodactylus ocellatus; Toxoplasma brumpti Coutelen from the iguana Iguana tuberculata; Toxoplasma colubri Tibaldi from the snakes Coluber melanoleucus and Coluber viridiflavus; Toxoplasma hammondi (Frenkel & Dubey) (a new combination for Hammondia hammondi) from the house mouse with oocysts in the domestic cat; Toxoplasma ranae Levine & Nye from the leopard frog Rana Pipiens; and Toxoplasma serpai Scorza, Dagert & Iturriza Arocha from the toad Bufo marinus. PMID:325203

Levine, N D

1977-02-01

305

Sensitivity of midge larvae of Chironomus tentans Fabricius (Diptera Chironomidae) to heavy metals  

Energy Technology Data Exchange (ETDEWEB)

The discharge of heavy metals into the natural waters has numerous obvious impacts on physical, chemical and biological parameters of aquatic ecosystem. Bioassay tests are important steps in establishing appropriate water quality criteria and standards for diverse use of ponds, lakes, streams and river waters. Therefore, the acute toxicities of various heavy metals to water flea Daphnia magna, and snail Lymnaea acuminata, and toad tadpoles Bufo mentanostictus have been reported from the authors' laboratory. Chironomid larvae might be particularly useful as indicators of water quality because they are widely distributed in freshwater systems and often from diverse communities within particular habitat. The aim of this study was to determine the acute toxicity of ten heavy metals to the midge larvae Chironomus tentans Fabricius, which forms an important link in aquatic food chain(s).

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

1989-03-01

306

Monitoring programs to assess reintroduction efforts: a critical component in recovery  

Directory of Open Access Journals (Sweden)

Full Text Available Reintroduction is a powerful tool in our conservation toolbox. However, the necessary follow-up, i.e. long-term monitoring, is not commonplace and if instituted may lack rigor. We contend that valid monitoring is possible, even with sparse data. We present a means to monitor based on demographic data and a projection model using the Wyoming toad (Bufo baxteri as an example. Using an iterative process, existing data is built upon gradually such that demographic estimates and subsequent inferences increase in reliability. Reintroduction and defensible monitoring may become increasingly relevant as the outlook for amphibians, especially in tropical regions, continues to deteriorate and emergency collection, captive breeding, and reintroduction become necessary. Rigorous use of appropriate modeling and an adaptive approach can validate the use of reintroduction and substantially increase its value to recovery programs.

V. Dreitz

2008-01-01

307

Ecotoxicological assessment of cobalt used as supplement in the diet of common carp Cyprinus carpio.  

Science.gov (United States)

Experiments were performed in the laboratory to determine if excess levels of Co used as dietary supplement (0.0, 0.05, 0.10 and 1.0%) to enhance growth of the fish Cyprinus carpio was safe for aquatic organisms. Lethal concentrations of Co for tadpole of toad Bufo melanostictus (96 h LC(50), 17.2 mg/L), oligochaet worm Branchiura sowerbyi (96 h LC(50), 179 mg/L) and crustacean zooplankton Diaptomus forbesi (96 h LC(50), 1.5 mg/L) were compared with the concentration of Co in the medium leached from the unused diets and faeces. The results indicated that the Co leached from diet containing 1.0% Co was ecotoxicologically unsafe for crustacean zooplankton. PMID:21858707

Mukherjee, Sanjukta; Kaviraj, Anilava

2011-11-01

308

The predator defence system of an African king cricket (Orthoptera: Anostostomatidae: does it help to stink?  

Directory of Open Access Journals (Sweden)

Full Text Available We examined the putative defence system of a king cricket,Onosandrus sp., in particular the efficacy of the noxious faeces against two types of predator: a lizard, the skink Mabuya striata (an active, diurnal forager, and the toad Bufo gutturalis (a nocturnal, ambush predator. Contrary to our predictions, the faeces did not act as a deterrent to either predator. Tongueflick trials with cotton scent applicators indicated that the skinks showed a heightened predatory response to king cricket faeces over king cricket integument, field cricket integument and an odourless control. We suggest that ‘primary’ defence mechanisms, such as nocturnal behaviour, cryptic colouration and immobility, are more effective than ‘secondary’ defence mechanisms, such as stridulation, kicking and defecation. Given that the noxious faeces already have a demonstrated role in inter- and intrasexual communication, we suggest that the assumed defensive role of the faeces is minor or an epiphenomenon.

Philip W. Bateman

2011-10-01

309

Ground water chemistry changes before major earthquakes and possible effects on animals.  

Science.gov (United States)

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

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

2011-06-01

310

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

Directory of Open Access Journals (Sweden)

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

Friedemann T. Freund

2011-06-01

311

Alien mink predation induces prolonged declines in archipelago amphibians.  

Science.gov (United States)

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

Ahola, Markus; Nordström, Mikael; Banks, Peter B; Laanetu, Nikolai; Korpimäki, Erkki

2006-05-22

312

EXPERIMENTAL MODEL TO INVESTIGATE DRUGS FOR EPILEPSY  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction.Epilepsy is one of the most common neurological disorders characterized by seizures. Epileptic seizures result from excessive, abnormal, or hyper synchronous neuronal activity in the brain. It is a public health problem that is not yet curable but which can be controlled. A high percentage of patients who suffer from epilepsy do not have seizures control even when using the existing treatments. Therefore, an experimental study was conducted with the objective of determining the effect of the Bufo-toxin in rats belonging to the BALB/c and the Wistar strainsin order to diagnose the group of symptoms that confer lethality to this toxin and which can work as a treatment to such disease.Methodology the bufo-toxin was obtained from toads, then it was placedin alcoholic solution and it was applied to the rats in doses of 5 by 5 for up to 20 Units with an insulin syringe though the intramuscular via. Observations were registered and when the rats died a post-mortem examination was conducted in order to describe the effect of the toxin in the internal organs. Results. The rats that were inoculated within 20 units of the toxin showed epileptic seizures and finally cerebral spill or heart attack. Discussion and conclusion. This model can be used to investigate on useful drugs against epilepsy and even heart diseases, such as, hypertension andheart attacks.

Jesús Carlos Ruvalcaba Ledezma

2013-09-01

313

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

Science.gov (United States)

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

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

2007-01-01

314

Post-meiotic intra-testicular sperm senescence in a wild vertebrate.  

Science.gov (United States)

There is growing interest in sperm senescence, both in its underlying mechanisms and evolutionary consequences, because it can impact the evolution of numerous life history traits. Previous studies have documented various types of sperm senescence, but evidence of post-meiotic intra-testicular sperm senescence in wild animals is lacking. To assess such senescence, we studied within-season changes in sperm motility in the common toad (Bufo bufo), where males produce all sperm prior to the breeding season. We found that males exposed to experimentally induced re-hibernation at the start of the breeding season, that is to experimentally lowered metabolic rates, stored sperm of significantly higher motility than males that were kept under seminatural conditions without females throughout the breeding season. This finding indicates that re-hibernation slows normal rates of sperm ageing and constitutes the first evidence to our knowledge of post-meiotic intra-testicular sperm senescence in a wild vertebrate. We also found that in males kept in seminatural conditions, sperm motility was positively related to the number of matings a male achieved. Thus, our results suggest that post-meiotic intra-testicular sperm senescence does not have a genetically fixed rate and may be modulated by temperature and possibly by mating opportunities. PMID:23226542

Hettyey, Attila; Vági, Balázs; Penn, Dustin J; Hoi, Herbert; Wagner, Richard H

2012-01-01

315

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

Science.gov (United States)

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

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

2014-03-01

316

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

International Nuclear Information System (INIS)

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

317

Toxicity of road salt to Nova Scotia amphibians  

International Nuclear Information System (INIS)

The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC50) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species. - Salt toxicity is presented as a mechanism affecting the distribution of amphibians and structure of amphibian communities in roadside wetlands

318

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

Science.gov (United States)

A leading hypothesis of amphibian population declines is that combinations of multiple stressors contribute to declines. We examined the role that chemical contamination, competition, and predation play singly and in combination in aquatic amphibian communities. We exposed larvae of American toads (Bufo americanus), southern leopard frogs (Rana sphenocephala), and spotted salamanders (Ambystoma maculatum) to overwintered bullfrog tadpoles (R. catesbeiana), bluegill sunfish (Lepomis macrochirus), the insecticide carbaryl, and ammonium nitrate fertilizer in 1000-L mesocosms. Most significantly, our study demonstrated that the presence of multiple factors reduced survival of B. americanus and A. maculatum and lengthened larval periods of R. sphenocephala. The presence of bluegill had the largest impact on the community; it eliminated B. americanus and A. maculatum and reduced the abundance of R. sphenocephala. Chemical contaminants had the second strongest effect on the community with the insecticide, reducing A. maculatum abundance by 50% and increasing the mass of anurans (frogs and toads) at metamorphosis; the fertilizer positively influenced time and mass at metamorphosis for both anurans and A. maculatum. Presence of overwintered bullfrogs reduced mass and increased time to metamorphosis of anurans. While both bluegill and overwintered bullfrog tadpoles had negative effects on the amphibian community, they performed better in the presence of one another and in contaminated habitats. Our results indicate that predicting deleterious combinations from single-factor effects may not be straightforward. Our research supports the hypothesis that combinations of factors can negatively impact some amphibian species and could contribute to population declines. PMID:17479852

Boone, Michelle D; Semlitsch, Raymond D; Little, Edward E; Doyle, Meaghan C

2007-01-01

319

Vertebrate phylogeny of hydrogen sulfide vasoactivity.  

Science.gov (United States)

Hydrogen sulfide (H(2)S) is a recently identified endogenous vasodilator in mammals. In steelhead/rainbow trout (Oncorhynchus mykiss, Osteichthyes), H(2)S produces both dose-dependent dilation and a unique dose-dependent constriction. In this study, we examined H(2)S vasoactivity in all vertebrate classes to determine whether H(2)S is universally vasoactive and to identify phylogenetic and/or environmental trends. H(2)S was generated from NaHS and examined in unstimulated and precontracted systemic and, when applicable, pulmonary arteries (PA) from Pacific hagfish (Eptatretus stouti, Agnatha), sea lamprey (Petromyzon marinus, Agnatha), sandbar shark (Carcharhinus milberti, Chondrichthyes), marine toad (Bufo marinus, Amphibia), American alligator (Alligator mississippiensis, Reptilia), Pekin duck (Anas platyrhynchos domesticus, Aves), and white rat (Rattus rattus, Mammalia). In otherwise unstimulated vessels, NaHS produced 1) a dose-dependent relaxation in Pacific hagfish dorsal aorta; 2) a dose-dependent contraction in sea lamprey dorsal aorta, marine toad aorta, alligator aorta and PA, duck aorta, and rat thoracic aorta; 3) a threshold relaxation in shark ventral aorta, dorsal aorta, and afferent branchial artery; and 4) a multiphasic contraction-relaxation-contraction in the marine toad PA, duck PA, and rat PA. Precontraction of these vessels with another agonist did not affect the general pattern of NaHS vasoactivity with the exception of the rat aorta, where relaxation was now dominant. These results show that H(2)S is a phylogenetically ancient and versatile vasoregulatory molecule that appears to have been opportunistically engaged to suit both organ-specific and species-specific homeostatic requirements. PMID:15345473

Dombkowski, Ryan A; Russell, Michael J; Schulman, Alexis A; Doellman, Meredith M; Olson, Kenneth R

2005-01-01

320

TRATAMENTO DE CÃES ENVENENADOS EXPERIMENTALMENTE POR BUFADIENOLÍDEOS (SUBSTÂNCIAS ENCONTRADAS NA SECREÇÃO DAS GLÂNDULAS PARATÓIDES DOS SAPOS DO GÊNERO BUFO TREATMENT OF DOGS EXPERIMENTALLY POISONED BY BUFADIENOLIDES (SUBSTANCES FOUND IN THE SECRETION OF PARATOID GLANDS OF THE Bufo GENUS FROGS  

Directory of Open Access Journals (Sweden)

Full Text Available

Os autores estudaram a administração de dois princípios medicamentosos no tratamento de dez cães envenenados experimentalmente por bufadienolídeos. A medicação utilizada atuou satisfatoriamente, ocorrendo a recuperação total em oito animais. Pelos resultados obtidos no presente experimento, podemos concluir: a A medicação utilizada atuou satisfatoriamente, e que nos animais envenenados em condições naturais, ela será tanto mais eficaz, quanto mais rapidamente for levada a efeito; b Com relação ao animal que morreu logo após ser medicado, a necrópsia e a histopatologia revelaram alterações orgânicas pré-existentes e que a nosso ver, foram agravadas através da ação do princípio tóxico utilizado.

The authors studied the Atropin and Amplictil effects in the treatment of 10 dogs poisoned by bufadienolideos. Eight dogs clinically recovered.

Paulo César Silva

2007-09-01

 
 
 
 
321

Acid precipitation studies in Colorado and Wyoming: interim report of surveys of montane amphibians and water chemistry  

Science.gov (United States)

Acid deposition may be detrimental or stressful to native populations of wildlife. Because many species of amphibians breed in shallow ponds created by spring rains or melting snow, they may be particularly vulnerable to the effects of acidification. From 1986 to 1988, we surveyed 105 locations in the central Rocky Mountains where amphibians had been recorded previously, and we found that two species of amphibians had experiences major losses. We found the northern leopard frog (Rana pipiens) at only 4 of 33 (12%) historically known localities, and the boreal toad (Bufo boreas) was present at 10 of 59 (17%) known localities. Three other species have not suffered region-wide declines. Tiger salamanders (Ambystoma tigrinum) and wood frogs (Rana sylvatica) were present at 45% and 69% of known localities respectively, and were observed at several localities were they had not been recorded previously. Chorus frogs (Pseudacris triseriata) suffered a catastrophic decline in population size in one population monitored since 1961, but regionally, this species was observed in 36 of 56 (64%) known localities and in another 19 localities where there were no previous records. Complete water chemistry was recorded for 41 localities, and pH was measured at 110 sites in total. Acid neutralizing capacity, pH, specific conductivity, and cation concentrations were negatively correlated with elevation. However, in mountain ponds and lakes, pH was rarely less than 6.0 during the amphibian breeding season. We tested the tolerance of embryos of the four species of frogs to low pH. The LC50 pH was 4.8 for chorus frogs, 4.4-4.7 for leopard frogs, 4.4-4.5 for boreal toads, and 4.2-4.3 for wood frogs. Survival of wood frog embryos declined when exposed to aluminum concentrations of 100 µg/L or greater, but boreal toad embryos survived exposure to aluminum concentrations of 400 µg/L. Acid deposition does not appear to be a major factor in the decline of leopard frogs and boreal toads. However, we have not yet investigated effects of sublethal pH on growth and development of tadpoles. Pollution remains suspect, but other factors, including natural fluctuations in population size, may account for the observed declines.

Corn, Paul Stephen; Stolzenburg, William; Bury, R. Bruce

1989-01-01

322

Enthalpic consequences of reduced chloride binding in Andean frog (Telmatobius peruvianus) hemoglobin  

DEFF Research Database (Denmark)

Based on the exothermic nature of heme oxygenation, the O2 affinity of hemoglobin (Hb) decreases with increasing temperature, which may be physiologically advantageous in augmenting O2 unloading from blood in warm tissues with elevated metabolic rates. This negative oxygenation enthalpy (?H (O)) may, however, become maladaptive, as in cold-tolerant ungulates where it may hamper O2 unloading in cold extremities and commonly is mitigated by an 'additional' chloride-binding site that decreases the temperature effect by increasing the endothermic release of Cl(-) ions upon O2 binding. Since no previous studies have focused on the consequences of reduced Cl(-) binding, I report and compare the enthalpic effects of chloride ions and the allosteric effector, ATP, on Hbs of the high-altitude aquatic Andean frog Telmatobius peruvianus that lacks the ?-chain chloride-binding site, and the lowland (sub-)tropical frog Xenopus laevis that has retained this site and exhibits high chloride sensitivity. In contrast to Xenopus, Telmatobius Hb exhibits high temperature sensitivity (high negative ?H') in the presence of Cl(-) ions, supporting the inverse relationship between the number of Cl(-)-binding sites and temperature sensitivity, and extending it to ectothermic vertebrates. The radically reduced chloride binding in Telmatobius Hb permits assessment of the enthalpy of ATP binding [(?H' ? -62 kJ (mol ATP)(-1) at pH 7.0]-which contrasts sharply with previously reported increases in temperature sensitivity by ATP in toad (Bufo bufo) Hb. The high temperature sensitivity associated with decreased chloride binding and low phosphate sensitivity of Telmatobius Hb likely promotes cutaneous O2 uptake in cold, high-altitude ponds and streams.

Weber, Roy E.

2014-01-01

323

Phylogenetic relationships and call structure in four African bufonid species  

Directory of Open Access Journals (Sweden)

Full Text Available ENGLISH ABSTRACT: Four species of toads of the genus Bufo. comprising three species endemic to southern Africa and one closely-related species, were examined electrophoretically to infer their phylogenetic relationships. The evolution of advertisement call structure in these species is discussed in relation to this phylogeny. Bufo rangeri and B. gutturalis, two species with very different call structures, are sister taxa. Two pairs of species with very similar call structures, B. pardalis and B. gutturalis, and B. rangeri and B. angusticeps, were only distantly related. Our results suggest that call parameters are poor characters to use in inferring phylogenies among congeneric species, probably because of selection for optimal audibility in different habitats, and because of the role that they play in premating isolation. The phylogeny derived from allozyme data agrees with evidence on albumin immunological distance, karyotype and morphology.***********AFRIKAANSE OPSOMMING: Vier spesies skurwepaddas van die genus Buto, bestaande uit drie wat endemies is in Suid-Afrika en een nou-verwante spesie, is elektroforeties ondersoek om hulle filogenetiese verwantskap af te lei. Die evolusie van die struktuur van die bekendstellingsroep by hierdie spesie word met betrekking tot hierdie filogenie bespreek. Buto rangeri en B. gutturalis, twee spesies met baie verskillende roepstrukture, is suster taksa. Twee pare van spesies met baie ooreenstemmende roepstrukture, B. pardalis en B. gutturalis, en B. rangeri en B. angusticeps, was slegs ver langs verwant. Ons resultate dui daarop dat roep-parameters swak kenmerke is om te gebruik by die aflei van filogenieë by verwante spesies, waarskynlik as gevolg van seleksie wat plaasvind vir optimale hoorbaarheid in verskillende habitatte, sowel as die rol wat hulle speel by die pre-paringsisolasie. Die filogenie wat van allosiemdata afgelei is, stem ooreen met getuienis oor albumien immunologiese afstand, kariotipe en morfologie .

W.S. Grant

2012-01-01

324

Paleoclimatic and paleoenvironmental context of the Early Pleistocene hominins from Dmanisi (Georgia, Lesser Caucasus) inferred from the herpetofaunal assemblage  

Science.gov (United States)

Dmanisi is currently the oldest Early Palaeolithic site discovered out of Africa. It has produced over 40 hominin remains, including a set of very informative skulls, in direct association with faunal remains and numerous lithic artifacts. Given the relevance of this locality, every effort is being made to reconstruct the landscapes where these hominins once lived. Amphibian and reptile remains from Dmanisi are here described for the first time and used as paleoclimatic and paleoenvironmental proxies. They comprise at least six taxa: a green toad (Bufo gr. Bufo viridis), the Greek tortoise (Testudo graeca), a green lizard (Lacerta gr. Lacerta viridis), a four-lined snake (Elaphe gr. Elaphe quatuorlineata), an indeterminate colubrid and a water snake (Natrix sp.). As these taxa are not extinct and their ecology can be directly studied, they can contribute to the reconstruction of the landscape and climate. The application of the Mutual Climatic Range method provides quantitative data indicating that during the hominin presence at Dmanisi climate was warm and dry, similar to the present-day Mediterranean climate. In comparison with today climate of Dmanisi, estimated mean annual temperature was 3.1 °C higher, with a greater increase of temperature in summer (+7.1 °C) than in winter (+4.7 °C). The mean annual precipitation was slightly lower (-65 mm) than the current level, with precipitation higher than current one during winter (+104 mm) but strongly lower during the other seasons, suggesting a stronger contrast in the rainfall regime during the year. From a paleoenvironmental point of view, fossil amphibians and reptiles all suggest the predominance of arid environments, from steppe or semi-desert to open Mediterranean forest, with stony or rocky substrate and bushy areas. The presence of permanent aquatic environments is also documented. These results mainly agree with those for large mammals, small mammals and the archaeobotanical analysis that indicate an important water stress suggesting a period of increased aridity contemporaneous with human occupations of the site.

Blain, Hugues-Alexandre; Agustí, Jordi; Lordkipanidze, David; Rook, Lorenzo; Delfino, Massimo

2014-12-01

325

Keystone predators (eastern newts, Notophthalmus viridescens) reduce the impacts of an aquatic invasive species.  

Science.gov (United States)

Predation, competition, and their interaction are known to be important factors that influence the structure of ecological communities. In particular, in those cases where a competitive hierarchy exists among prey species, the presence of certain keystone predators can result in enhanced diversity in the prey community. However, little is known regarding the influence of keystone predator presence on invaded prey communities. Given the widespread occurrence of invasive species and substantial concern regarding their ecological impacts, studies on this topic are needed. In this study I used naturalistic replications of an experimental tadpole assemblage to assess the influence of predatory eastern newts, Notophthalmus viridescens, on the outcome of interspecific competition among native and nonindigenous tadpoles. When newts were absent, the presence of the tadpoles of one invasive species, the Cuban treefrog, Osteopilus septentrionalis, resulted in decreased survival and growth rate of the dominant native species, Bufo terrestris, and dominance of the tadpole assemblage by O. septentrionalis. However, the presence of one adult newt generally reduced or eliminated the negative impacts of O. septentrionalis tadpoles, resulting in comparable survival and performance of native species in invaded and noninvaded treatments. Differential mortality among the tadpole species suggests that newts preyed selectively on O. septentrionalis tadpoles, supporting the hypothesis that newts acted as keystone predators in the invaded assemblage. The presence of nonindigenous larval cane toads, Bufo marinus, did not significantly affect native species, and this species was not negatively affected by the presence of newts. Collectively, these results suggest that eastern newts significantly modified the competitive hierarchy of the invaded tadpole assemblage and reduced the impacts of a competitively superior invasive species. If general, these results suggest that the presence of certain species may be an essential factor regulating the ecological impacts of biological invasions. PMID:16463174

Smith, Kevin G

2006-06-01

326

Keystone predators (eastern newts, Notophthalmus viridescens) reduce the impacts of an aquatic invasive species  

Science.gov (United States)

Predation, competition, and their interaction are known to be important factors that influence the structure of ecological communities. In particular, in those cases where a competitive hierarchy exists among prey species, the presence of certain keystone predators can result in enhanced diversity in the prey community. However, little is known regarding the influence of keystone predator presence on invaded prey communities. Given the widespread occurrence of invasive species and substantial concern regarding their ecological impacts, studies on this topic are needed. In this study I used naturalistic replications of an experimental tadpole assemblage to assess the influence of predatory eastern newts, Notophthalmus viridescens, on the outcome of interspecific competition among native and nonindigenous tadpoles. When newts were absent, the presence of the tadpoles of one invasive species, the Cuban treefrog, Osteopilus septentrionalis, resulted in decreased survival and growth rate of the dominant native species, Bufo terrestris, and dominance of the tadpole assemblage by O. septentrionalis. However, the presence of one adult newt generally reduced or eliminated the negative impacts of O. septentrionalis tadpoles, resulting in comparable survival and performance of native species in invaded and noninvaded treatments. Differential mortality among the tadpole species suggests that newts preyed selectively on O. septentrionalis tadpoles, supporting the hypothesis that newts acted as keystone predators in the invaded assemblage. The presence of nonindigenous larval cane toads, Bufo marinus, did not significantly affect native species, and this species was not negatively affected by the presence of newts. Collectively, these results suggest that eastern newts significantly modified the competitive hierarchy of the invaded tadpole assemblage and reduced the impacts of a competitively superior invasive species. If general, these results suggest that the presence of certain species may be an essential factor regulating the ecological impacts of biological invasions.

Smith, K.G.

2006-01-01

327

SPATIAL SCALE OF AUTOCORRELATION IN WISCONSIN FROG AND TOAD SURVEY DATA  

Science.gov (United States)

The degree to which local population dynamics are correlated with nearby sites has important implications for metapopulation dynamics and landscape management. Spatially extensive monitoring data can be used to evaluate large-scale population dynamic processes. Our goals in this ...

328

Little Frog and Toad: Interaction of Orthography and Phonology in Polish Spelling.  

Science.gov (United States)

Investigates the interaction of lexical and non-lexical processes in spelling through lexical priming of non-lexical spelling in Polish. Explains that orthographic choice for nonwords was assessed under free and primed spelling conditions for both adults and children using direct and associative priming. Finds that lexical orthography influences…

Kaminska, Zofia

2003-01-01

329

Reviled and Revered: Toads, Turtles, Snakes, Salamanders, and Other Creepers and Crawlers  

Science.gov (United States)

Reviled and Revered is an excellent set of lesson plans on reptiles and amphibians, or herps, created by the Smithsonian Institution's Office of Education for grades 3-8. Reviled and Revered is just one example of the interdisciplinary, multicultural learning materials developed by the Smithsonian "to help teachers bring into their classrooms the educational power of museums and other community resources." The Web site includes five interesting lesson plans, most of which blend biology with an examination of our cultural attitudes toward herps.

330

75 FR 37358 - Endangered and Threatened Wildlife and Plants; Revised Critical Habitat for the Arroyo Toad  

Science.gov (United States)

...planting wetland mitigation sites; (2) revegetation of riparian areas; (3) removal of invasive plants such as arundo (Arundo donax) and tamarisk (Tamarix sp.); (4) protecting wetlands from urban runoff by establishing a...

2010-06-29

331

Participation of nitric oxide in the nucleus isthmi in CO2-drive to breathing in toads  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The nucleus isthmi (NI) is a mesencephalic structure of the amphibian brain. It has been reported that NI plays an important role in integration of CO2 chemoreceptor information and glutamate is probably involved in this function. However, very little is known about the mechanisms involved. Recently, it has been shown that nitric oxide synthase (NOS) is expressed in the brain of the frog. Thus the gas nitric oxide (NO) may be involved in different functions in the brain of amphibians and may ...

Gargaglioni, L. H.; Branco, L. G. S.

1999-01-01

332

A new species of arboreal toad (Anura : Bufonidae : Chaunus) from Madidi National Park, Bolivia  

Science.gov (United States)

A new arboreal species of the Chaunus veraguensis group is described for the humid montane forest of Madidi National Park, in northern Bolivia. The new species differs from other species in the group by the combination small size, long and slender extremities, webbed hands, conspicuous tympanic membrane, well developed parotoid glands, absence of large glands on dorsum and extremities, nuptial excrescences of males composed of pungent spines on dorsal surface of thumb, greenish-brown coloration on dorsum with red warts in life, and green iris. It is only known from two nearby localities in the Serran Eslabon, Department La Paz. An operational key for species in the C. veraguensis group is provided.

Padial, J.M.; Reichle, S.; McDiarmid, R.; De la Riva, I.

2006-01-01

333

Cane Toad or Computer Mouse? Real and Computer-Simulated Laboratory Exercises in Physiology Classes  

Science.gov (United States)

Traditional practical classes in many countries are being rationalised to reduce costs. The challenge for university educators is to provide students with the opportunity to reinforce theoretical concepts by running something other than a traditional practical program. One alternative is to replace wet labs with comparable computer simulations.…

West, Jan; Veenstra, Anneke

2012-01-01

334

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

Science.gov (United States)

...least of all. In a study using pitfall traps, Holland and Sisk (2001, pp. 1-32...of shallow pools and sparsely vegetated sand and gravel bars for breeding and rearing...channels and terraces and redistributes sand and sediment, such that breeding...

2011-02-09

335

A survey of Blastocystis infection in anuran and urodele amphibians.  

Science.gov (United States)

Blastocystis infection in amphibians was surveyed in three species of anuran and one species of urodele amphibians captured at two distinct locations in Japan. All three species of frogs were highly infected with Blastocystis, while 69 individual urodele newts, Cynopus pyrrhogaster, were negative for infection. Eleven Blastocystis isolates (47.8%) were recovered from 23 Rana nigromaculata leopard frogs. Twenty-three (92%) of 25 Rana catesbeiana bullfrogs and all (100%) of 24 Bufo japonicus japonicus toads were positive for Blastocystis. Two distinct populations of the toad and bullfrog showed a high prevalence (100 or 84.6%) of Blastocystis infection, while in two populations of the leopard frog only one population was positive for Blastocystis (84.6%). Three Blastocystis isolates from different species of the frogs were established. Since none of the three isolates could survive at 37 degrees C, a temperature tolerance assay was performed to assess the optimal growth temperature and to determine the range of non-lethal temperatures. During the exponential growth phase of 3- or 4-day cultures at 25 degrees C, three isolates were exposed to 4, 28, 31, or 34 degrees C for 3 days and then returned to 25 degrees C to monitor the cell growth. Based on the optimal growth temperatures and different ranges of temperature tolerance among the three new isolates from frogs and two known species, Blastocystis hominis and Blastocystis lapemi, it was established that the three isolates recovered from different species of frogs had different physiological features from B. hominis and B. lapemi. PMID:15177714

Yoshikawa, Hisao; Morimoto, Keiko; Nagashima, Minako; Miyamoto, Naoko

2004-06-21

336

Interactions of an insecticide, herbicide, and natural stressors in amphibian community mesocosms  

Science.gov (United States)

Amphibians developing in wetlands embedded within or near agricultural lands may frequently encounter chemical mixtures. The objectives of our study were to determine the effects that post-application concentrations of an insecticide (carbaryl) and an herbicide (atrazine) have on body mass, development, and survival of two anuran species (southern leopard frog, Rana sphenocephala; American toad, Bufo americanus) and two caudate species (spotted salamander, Ambystoma maculatum; small-mouthed salamander, A. texanum) reared in outdoor cattle tank mesocosms. In one experiment, we manipulated tadpole density (low or high), carbaryl exposure (0, 3.5, 7.0 mg/L), and atrazine exposure (0 or 200 ??g/L) to test for effects on development, mass, and survival of larvae. In a second experiment, we manipulated pond hydroperiod (constant or drying), carbaryl exposure (0 or 5 mg/L), and atrazine exposure (0 or 200 ??g/L) to test for effects on mass, time, and survival to metamorphosis. Salamanders were virtually eliminated in carbaryl treatments, indicating that at realistic levels, this insecticide could cause population declines for salamanders in contaminated habitats. Carbaryl also had negative effects on toad survival. Exposure to atrazine had negative effects on body size, development, and time to metamorphosis in anuran species, which were associated with reduced chlorophyll levels. Both chemicals interacted significantly with density or hydroperiod, indicating that the environmental conditions could influence the impact of a contaminant. A significant atrazine-by-carbaryl interaction resulted in smaller and less developed spotted salamander larvae than in control ponds. Atrazine exposure, however, appeared to moderate negative effects of carbaryl for spotted salamanders. Our research suggests that important changes in the community's food web result from chemical exposure, which influence the susceptibility of amphibian species to contaminants.

Boone, M.D.; James, S.M.

2003-01-01

337

Variation in anti-parasite behaviour and infection among larval amphibian species.  

Science.gov (United States)

Along with immune defences, many animals exhibit effective anti-parasite behaviours such as parasite avoidance and removal that influence their susceptibility to infection. Host ecology and life history influence investment into comparatively fixed defences such as innate immunity but may affect the strength of anti-parasite behaviours as well. We investigated activity levels in five different species of larval amphibian with varying life histories and ecology in control, novel food stimulus, and trematode parasite (Echinoparyphium sp.) threat conditions. There was a significant interaction of species and treatment given that American toad (Bufo americanus), wood frog (Lithobates sylvaticus), and bullfrog (Lithobates catesbeianus) tadpoles generally increased their activity when parasite infectious stages were present while grey tree frogs (Hyla versicolor) and northern leopard frogs (Lithobates pipiens) did not, even though activity was negatively related to infection. In addition, there was considerable variation among species in their susceptibility to parasitism, with infection prevalence ranging from 17% in bullfrog tadpoles to 70% in wood frogs. However, amphibian life history (larval and adult traits) was not related to parasitism or level of anti-parasite behaviour at the species level. Consequently, we suggest that future investigations include more species with a range of life history traits and also consider host ecology, particularly if conspicuous anti-parasite behaviours are more likely in amphibian species that experience a relatively low risk of predation. PMID:24337712

Koprivnikar, Janet; Redfern, Julia C; Mazier, Hannah L

2014-04-01

338

A survey on the faunal diversity of Savar Upazila, Dhaka, Bangladesh.  

Science.gov (United States)

A survey was conducted during January to December 2006 to assess the status of faunal diversity of Savar Upazila, Dhaka, Bangladesh. A total of 30 species of birds, 24 species of winter birds, 7 species of reptiles, 3 species of amphibians, 15 species of mammalians and 32 species of fishes were recorded. Relative abundance of those species were determined. Of the birds, House Sparrow (Passer domesticus) was abundant while Blyth's Kingfisher (Alcedo hercules), Rock Eagle Owl (Bubo bengalensis), Hooded Pitta (Pitta sordida), Black-headed Oriole (Oriolus xanthornus), White-winged Duck (Cairina seululala) and Duck (Anser indicus) were rare. The relative abundance of winter bird could not be assessed because of their migratory habit. Striped keelback (Amphiesma stolata) and Common Smooth Water Snake (Enhydris enhydris) were very common while Black pond turtle (Geoclyms hamiltonii) and Pond tortoise (Melanochelys trijuga) were recorded as endangered. Common Toad (Bufo melanostictus) were abundant but Bull Frog (Rana tigrina) was rare. Asiatic Wild Dog (Cuon alpinus) and House Mouse (Mus musculus) were abundant while Common Otter, Large Indian Civet, Irrawaddy River Dolphin, Indian Hare were rare. Carpu, Silver carp, Tilapia, Nilotica were abundant while, Freshwater Garfish, One stripe spinyeel and Grey Featherback were rare. Landfilling, deforestation, poaching, industrial effluents and current jal were identified as major threats to the faunal diversity of Savar area. PMID:18817158

Hossain, Eftekhar; Chowdhury, Mohammad Mamun; Iqubal, Kazi Farhed

2008-02-01

339

Response of amphibian liver to external gamma irradiation  

International Nuclear Information System (INIS)

Adults toads (Bufo andersonii) were exposed to four doses (i.e. 2.25, 4.50, 6.75 and 9.00 Gy) of gamma radiation from a 60Co source. Five animals were sacrificed at each post-irradiation interval of 1, 2, 3, 7 and 14 days. The liver was fixed in Bouin's fluid and after processing in a routine way, it was examined histologically. The radiation effects were found dose-dependent. The pathological changes appeared on day 3 in the 2.25 Gy group and on day 1 in all the other dose groups. The radiolesions increased gradually in severity up to day 3 in the latter groups followed by onset of recovery on the 7th day. The liver appeared normal in structure on the last interval studied (14 days) in 2.25, 4.50 and 6.75 Gy groups but a few lesions still persisted in the 9.0 Gy group. On day 14 lymphoid structures exhibiting lymphopoiesis were also observed in the 9.0 Gy group. (author)

340

Determination of intracellular pH and PCO2 after metabolic inhibition by fluoride and nitrilotriacetic acid.  

Science.gov (United States)

Mean intracellular pH (pHi) and PCO2 (PiCO2) have been analysed based on pH and total CO2 measurements in tissue homogenates. Tissues were sampled from undisturbed worms (Sipunculus nudus), squid (Illex illecebrosus), trout (Salmo gairdneri), toads (Bufo marinus), and rats. Homogenate metabolism was inhibited by the addition of potassium fluoride and nitrilotriacetic acid (NTA). Model calculations revealed that the influence of dilution, medium buffers, and contamination by extracellular fluids was negligible. In white muscle tissue the resulting pHi values were virtually the same as found in studies using DMO (dimethyloxazolidinedione). If large fractions of mitochondria were present (e.g. in heart muscle), DMO derived pHi values were considerably higher, probably representing overestimates. Homogenate derived pHi values are concluded to represent the effective mean pHi by taking into account pH gradients, and the volumes and buffering of cellular compartments. High time resolution and small variability make this method especially useful to assess rapid changes in pHi, e.g. in exercising animals. PMID:2124717

Pörtner, H O; Boutilier, R G; Tang, Y; Toews, D P

1990-08-01

 
 
 
 
341

Do parasitic trematode cercariae demonstrate a preference for susceptible host species?  

Science.gov (United States)

Many parasites are motile and exhibit behavioural preferences for certain host species. Because hosts can vary in their susceptibility to infections, parasites might benefit from preferentially detecting and infecting the most susceptible host, but this mechanistic hypothesis for host-choice has rarely been tested. We evaluated whether cercariae (larval trematode parasites) prefer the most susceptible host species by simultaneously presenting cercariae with four species of tadpole hosts. Cercariae consistently preferred hosts in the following order: Anaxyrus (?=?Bufo) terrestris (southern toad), Hyla squirella (squirrel tree frog), Lithobates (?=?Rana) sphenocephala (southern leopard frog), and Osteopilus septentrionalis (Cuban tree frog). These host species varied in susceptibility to cercariae in an order similar to their attractiveness with a correlation that approached significance. Host attractiveness to parasites also varied consistently and significantly among individuals within a host species. If heritable, this individual-level host variation would represent the raw material upon which selection could act, which could promote a Red Queen "arms race" between host cues and parasite detection of those cues. If, in general, motile parasites prefer to infect the most susceptible host species, this phenomenon could explain aggregated distributions of parasites among hosts and contribute to parasite transmission rates and the evolution of virulence. Parasite preferences for hosts belie the common assumption of disease models that parasites seek and infect hosts at random. PMID:23272084

Sears, Brittany F; Schlunk, Andrea D; Rohr, Jason R

2012-01-01

342

Differential effects of testosterone and 17?-estradiol on gonadal development in five anuran species.  

Science.gov (United States)

Sex hormones are essential for sexual differentiation and play a key role in the development of gonads in amphibians. The goal of this study was to evaluate the influence of exogenous sex steroids, testosterone, and 17?-estradiol (E(2)) on development of gonads in five anuran species differing in their evolutionary positions, sex determination, and mode of gonadogenesis. We found that in two closely related species of fire-bellied toad, Bombina bombina and Bombina variegata, testosterone and E(2) exposure results in sex reversal as well as intersex and undifferentiated gonads. Similarly, sex reversal was observed in Hyla arborea after exposure to male or female sex steroids. Xenopus laevis was sensitive to E(2) but only moderately to testosterone. In Bufo viridis, treatment with either sex hormone provoked a developmental delay in gonads and Bidder's organs. Therefore, susceptibility to hormonal sex reversal appeared species dependent but unrelated to genetic sex determination and the type of gonadogenesis. We also found that the onset of sex steroid exposure influences gonad differentiation and the meiotic status of the germ cells depends on their location within the gonad. Our findings reveal differential sensitivity of amphibians to testosterone and E(2), establishing a hierarchy of sensitivity to these hormones among different anuran species. PMID:22641770

Piprek, Rafa? P; Pecio, Anna; Kubiak, Jacek Z; Szymura, Jacek M

2012-08-01

343

Hormone effects on transport in cultured epithelia with high electrical resistance.  

Science.gov (United States)

Three continuous lines of amphibian epithelial cells form epithelia with a high transepithelial resistance (greater than 4,000 omega . cm2) in culture. The cell lines are TB-M and TB-6c, derived from the urinary bladder of Bufo marinus, and A6, derived from the kidney of Xenopus laevis. Short-circuit current is equivalent to net mucosa-to-serosa sodium transport in two cell lines and slightly exceeds sodium transport in epithelia formed by TB-6c cells. None of the cell lines has an adenylate cyclase response or a transport or permeability response to vasopressin. Water permeability is low in all three cell lines and is not affected by adenosine 3',5'-cyclic monophosphate (cAMP). In the three lines of cells, cAMP and aldosterone each increases short-circuit current with a time course similar to that seen in naturally occurring epithelia. In contrast to the toad urinary bladder and epithelia of line TB-M in which the aldosterone stimulation of short-circuit current is associated with a fall in transepithelial resistance, there is no change in resistance across epithelia of lines TB-6c and A6. There is also a striking difference in the sensitivity of the three lines to inhibition of short-circuit current by amiloride. PMID:6259946

Handler, J S; Perkins, F M; Johnson, J P

1981-03-01

344

Synergistic impacts of malathion and predatory stress on six species of North American tadpoles.  

Science.gov (United States)

The decline of many amphibian populations is associated with pesticides, but for most pesticides we know little about their toxicity to amphibians. Malathion is a classic example; it is sprayed over aquatic habitats to control mosquitoes that carry malaria and the West Nile virus, yet we know little about its effect on amphibians. I examined the survival of six species of tadpoles (wood frogs, Rana sylvatica; leopard frogs, R. pipiens; green frogs, R. clamitans; bullfrogs, R. catesbeiana; American toads, Bufo americanus; and gray tree frogs, Hyla versicolor) for 16 d in the presence or absence of predatory stress and six concentrations of malathion. Malathion was moderately toxic to all species of tadpoles (median lethal concentration [LC50] values, the concentration estimated to kill 50% of a test population, ranged from 1.25-5.9 mg/L). These values are within the range of values reported for the few amphibians that have been tested (0.2-42 mg/L). In one of the six species, malathion became twice as lethal when combined with predatory stress. Similar synergistic interactions have been found with the insecticide carbaryl, suggesting that the synergy may occur in many carbamate and organophosphate insecticides. While malathion has the potential to kill amphibians and its presence is correlated with habitats containing declining populations, its actual role in amphibian declines is uncertain given the relatively low concentration in aquatic habitats. PMID:15095908

Relyea, Rick A

2004-04-01

345

Hallucinogenic drugs in pre-Columbian Mesoamerican cultures.  

Science.gov (United States)

INTRODUCTION: The American continent is very rich in psychoactive plants and fungi, and many pre-Columbian Mesoamerican cultures used them for magical, therapeutic and religious purposes. OBJECTIVES: The archaeological, ethno-historical and ethnographic evidence of the use of hallucinogenic substances in Mesoamerica is reviewed. RESULTS: Hallucinogenic cactus, plants and mushrooms were used to induce altered states of consciousness in healing rituals and religious ceremonies. The Maya drank Balché (a mixture of honey and extracts of Lonchocarpus) in group ceremonies to achieve intoxication. Ritual enemas and other psychoactive substances were also used to induce states of trance. Olmec, Zapotec, Maya and Aztec used peyote, hallucinogenic mushrooms (teonanacatl: Psilocybe sp.) and the seeds of ololiuhqui (Turbina corymbosa), that contain mescaline, psilocybin and lysergic acid amide, respectively. The skin of the toad Bufo sp. contains bufotoxins with hallucinogenic properties, and was used since the Olmec period. The jimson weed (Datura stramonium), wild tobacco (Nicotiana rustica), water lily (Nymphaea ampla) and Salvia divinorum were used for their psychoactive effects. Fungal stones dating from 3000 BC have been found in ritual contexts in Mesoamerica. Archaeological evidence of peyote use dates back to over 5000 years. Several chroniclers, mainly Fray Bernardino de Sahagún, described their effects in the sixteenth century. CONCLUSIONS: The use of psychoactive substances was common in pre-Columbian Mesoamerican societies. Today, local shamans and healers still use them in ritual ceremonies in Mesoamerica. PMID:21893367

Carod-Artal, F J

2011-09-01

346

Acute toxicity of synthetic pyrethroid cypermethrin to some freshwater organisms.  

Science.gov (United States)

Ninety-six hours static bioassays were made in the laboratory to determine acute toxicity of cypermethrin to five non-target freshwater organisms belonging to different taxa and niche. Susceptibility of the organisms to cypermethrin was in the order: the crustacean Diaptomus forbesi > the aquatic insect Ranatra filiformis > the freshwater carp Cyprinus carpio > the tadpole larva of the toad Bufo melanostictus > the oligochaet worm Branchiura sowerbyi. Ninety-six hours LC50 values of aqueous cypermethrin ranged from 0.03 microg/L for the crustacean to 9.0 microg/L for the tadpole larva. The value was very high (71.12 microg/L) for the oligochaet worm. LC50 values changed with hours of exposure till 72 h after which cypermethrin became inactive in both aqueous and acetone solution. Acetone solution of cypermethrin was more toxic to B. sowerbyi, C. carpio and the tadpole larva. There was no significant difference in susceptibility of any other test organism between aqueous and acetone solution of cypermethrin. PMID:18058051

Saha, Suchismita; Kaviraj, Anilava

2008-01-01

347

The effects of dexamethasone (DXM) and vitamin A on the growth and metamorphosis of gamma irradiated, thyroxine induced Bufo melanostictus tadpoles  

International Nuclear Information System (INIS)

This study deals with the effects of vitamin A and dexamethasone (DXM) on the metamorphosis of irradiated tadpoles. Results indicate that hypervitaminosis A depresses the metamorphosing action of thyroxine for several days. On the contrary, dexamethasone accelerates the action of exogenous thyroxine on tadpoles. Thus present data suggest that DXM supresses STH synthesis and promotes TSH secretion. Moreover, muscle appears to be its target tissue and DXM seems to promote the proteolytic digestion of the larval tail. (author)

348

"...Lleben...las colas a las varrigas de los bufos...": balleneros guipuzcoanos en las "matanzas" de ballenas de Galicia y Asturias durante los siglos XVI y XVII  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Este artículo analiza la presencia de balleneros guipuzcoanos, principalmente procedentes de Orio y Zarauz, en las pesquerías de ballenas de las costas gallegas y asturianas, durante los siglos XVI y XVII. La investigación se organiza en tres bloques bien diferenciados. El primero de ellos analiza el temprano desarrollo de las campañas balleneras vascas en el Cantábrico occidental durante la Baja Edad Media. Un segundo apartado se ocupa de aspectos organizativos relacionad...

Arago?n Ruano, A?lvaro; Alberdi Lonbide, Xavier

2012-01-01

349

THE HERPETOFAUNA OF THE NATURAL RESERVATION FROM THE INFERIOR COURSE OF THE TUR RIVER AND ITS SURROUNDING AREAS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the studied area we encountered 14 species of amphibians (Salamandra salamandra, Triturus vulgaris, Triturus cristatus, Triturus dobrogicus, Bombina bombina, Bombina variegata, Pelobates fuscus, Hyla arborea, Bufo bufo, Bufo viridis, Rana ridibunda, Rana lessonae, Rana dalmatina, Rana arvalis) and 9 species of reptiles (Emys orbicularis, Lacerta agilis, Lacerta viridis, Zootoca vivipara, Anguis fragilis, Natrix natrix, Coronella austriaca, Elaphe longissima and Vipera berus). Hybrids betwe...

Covaciu-marcov, Severus D.; Sas, Istvan; Cicort-lucaciu, Alfred St; Bogdan, Horia V.; Kovacs, Eva H.; Maghiar, Cosmin

2008-01-01

350

Contributions to knowledge regarding the geographical distribution of the herpetofauna of Dobrudja, Romania  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In Dobrudja we encountered 10 species of amphibians (Triturus dobrogicus, Bombina bombina, Hyla arborea, Pelobates fuscus, Pelobates syriacus, Bufo bufo, Bufo viridis, Rana dalmatina, Rana ridibunda, Rana lessonae), 16 species of reptiles (Emys orbicularis, Testudo graeca, Ablepharus kitaibelli, Lacerta agilis, Lacerta viridis, Lacerta trilineata, Podarcis taurica, Podarcis muralis, Eremias arguta, Coronella austriaca, Zamensis longissimus, Elaphe quatuorlineata, Dolichophis caspius, Natrix n...

Bogdan, Horia V.; Strugariu, Alexandru; Sas, Istvan; Cicort-lucaciu, Alfred-s?tefan; Ghira, Ioan; Covaciu-marcov, Severus-daniel

2006-01-01

351

Quantitative study of Trichodina heterodentata (Ciliophora: Mobilia infrapopulations infesting tadpoles of a Brazilian endemic toad Rhinella pombali (Anura: Bufonidae  

Directory of Open Access Journals (Sweden)

Full Text Available In this work we investigated the quantitative aspects of the relationship between Rhinella pombali (Baldissera, Caramaschi & Haddad, 2004 tadpoles and their trichodinid ectoparasites. Specimens were collected from a small stream located at an agricultural area between rainforest fragments in southeastern Brazil. A total of 80 tadpoles were investigated. Trichodina heterodentata Duncan, 1977 was the only trichodinid ciliate species recovered. All tadpoles were naturally infested by T. heterodentata with a mean intensity of 695.14 ± 33.33 trichodinid ciliates per tadpole. A positive correlation was observed between the intensity of the infestation and tadpole weight. Intensity of infestation did not significantly influence mean trichodinid diameter in the populations studied. This is the first study investigating density-dependent effects in interspecific interactions between trichodinids and anurans.

Noemi M. Fernandes

2011-12-01

352

Quantitative study of Trichodina heterodentata (Ciliophora: Mobilia) infrapopulations infesting tadpoles of a Brazilian endemic toad Rhinella pombali (Anura: Bufonidae)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english In this work we investigated the quantitative aspects of the relationship between Rhinella pombali (Baldissera, Caramaschi & Haddad, 2004) tadpoles and their trichodinid ectoparasites. Specimens were collected from a small stream located at an agricultural area between rainforest fragments in southe [...] astern Brazil. A total of 80 tadpoles were investigated. Trichodina heterodentata Duncan, 1977 was the only trichodinid ciliate species recovered. All tadpoles were naturally infested by T. heterodentata with a mean intensity of 695.14 ± 33.33 trichodinid ciliates per tadpole. A positive correlation was observed between the intensity of the infestation and tadpole weight. Intensity of infestation did not significantly influence mean trichodinid diameter in the populations studied. This is the first study investigating density-dependent effects in interspecific interactions between trichodinids and anurans.

Noemi M., Fernandes; Bianca, Sartini; Roberto J. P., Dias; Marta, D' Agosto.

2011-12-01

353

Retention of antidiuretic hormone-induced particle aggregates by luminal membranes separated from toad bladder epithelial cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Aggregates of intramembrane particles appear in the luminal membranes of renal collecting duct and amphibian bladder cells after stimulation by antidiuretic hormone (ADH). We undertook this freeze-fracture study to determine whether particle aggregates, once in place, remain in the luminal membrane of the amphibian bladder after the membrane is physically separated from the rest of the cell. We found that the aggregates do remain in high yield in isolated membranes stabilized with a bifunctio...

1982-01-01

354

Establishment, characterization and immortalization of a fibroblast cell line from the Chinese red belly toad Bombina maxima skin  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The skin of the amphibian Bombina maxima is rich in biologically active proteins and peptides, most of which have mammalian analogues. The physiological functions of most of the mammalian analogues are still unknown. Thus, Bombina maxima skin may be a promising model to reveal the physiological role of these proteins and peptides because of their large capacity for secretion. To investigate the physiological role of these proteins and peptides in vitro, a fibroblast cell line was successfully...

Xiang, Yang; Gao, Qian; Su, Weiting; Zeng, Lin; Wang, Jinhuan; Hu, Yi; Nie, Wenhui; Ma, Xutong; Zhang, Yong; Lee, Wenhui; Zhang, Yun

2011-01-01

355

Tribulations of a prostate cancer trial - lessons learned from TOAD, a cancer council Victoria and Transtasman Radiation Oncology Group Trial  

International Nuclear Information System (INIS)

Full text: From 2004-2009 a total of 226 out of a target of 750 prostate cancer patients have been randomised into the Timing of Androgen Deprivation trial between immediate and delayed androgen deprivation. A screening log was kept by participating centres for the first 928 patients, which documented the reasons for non-entry into the trial; 42.7% of screened patients were ineligible and a further 33.0% were not entered for other reasons. Fewer than 10% of patients cited not wanting to be part of a clinical trial as a reason for non-entry. Strategies to improve recruitment included broadening the eligibility criteria, encouraging international collaboration, the use and support of research nurses in the private health care environment, and the use of phone follow-up. Recruitment will be completed at the number originally intended to inform the interim analysis designed to test the validity of the statistical assumptions, and a combined survival analysis with the Canadian study is planned.

356

Mechanisms of adreno- and cholinoreceptors in isolated pulmonary and systemic vasculature of the cane toad (Rhinella marina)  

DEFF Research Database (Denmark)

While the overall autonomic regulation of the heart and vasculature of anurans has been studied in some detail, little is known about the role of the adreno- and cholinoreceptors in smooth muscle when looking at resistance in the pulmonary and systemic vessels. Vascular smooth muscle is the primary site of regulation of resistance and therefore holds the capacity to control blood flow and pressure. This vascular control allows amphibians to regulate their shunt, i.e. partially bypassing either the pulmonary or systemic circuit. Shunting in amphibians has been studied due to their multiple respiratory modalities and their ontogeny including fundamental morphological changes during metamorphosis. Here we use wire myography to evaluate how the vascular tone of isolated blood vessels from the pulmocutaneous, pulmonary, cutaneous and systemic segments respond to sympathetic and parasympathetic stimulation. Hence, myography on vessels ranging from 0.2 to 2.0 mm allow for the investigation of isometric response to agonists and antagonists of smooth muscle with no autonomic tone. This provides the possibility of mapping the function of adreno- and cholinoreceptor in vascular regulation in anurans.

Pedersen, Pil Birkefeldt MØller; Wang, Tobias

357

A curious case of hervibory in the common toad Rhinella arenarum during hibernation in captivity conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Jungblut, Lucas David; Pozzi, Andrea Gabriela; Paz, Dante Agusti?n

2013-01-01

358

Are hedgehogs like pigs, or tortoises like toads? : language-specific effects of compound structure on conceptualisation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

How far can language-specific structures influence conceptualisation? After a period of time where the discussion of any ‘Whorfian’ effects tended to be considered of little scientific merit, the recent decade has seen a renewed interest in this question. In particular, studies have aimed to tease apart ‘thinking for speaking’ from general cognition (cf. Slobin 1996, Stutterheim & Nüse 2002) and have shown that language-specific differences can often be observed in verbalisation as w...

Wiese, Heike

2010-01-01

359

Distribution of Boreal Toad Populations in Relation to Estimated UV-B Dose in Glacier National Park, Montana, USA  

Science.gov (United States)

This work provides information on amphibian distributions as well as the range of UV-B exposure in mountain habitats, and will be of use to scientists interested in tracking changes in amphibian distributions and abundance, and spatial and temporal patterns of UV-B exposure...

360

Late Miocene diversification and phylogenetic relationships of the huge toads in the Rhinella marina (Linnaeus, 1758) species group (Anura: Bufonidae).  

Science.gov (United States)

We investigated the phylogeny and biogeography of the Rhinella marina group, using molecular, morphological, and skin-secretion data, contributing to an understanding of Neotropical faunal diversification. The maximum-parsimony and Bayesian analyzes of the combined data recovered a monophyletic R. marina group. Molecular dating based on Bayesian inferences and fossil calibration placed the earliest phylogenetic split within the R. marina group at ? 10.47 MYA, in the late Miocene. Two rapid major diversifications occurred from Central Brazil, first northward (? 8.08 MYA) in late Miocene and later southward (? 5.17 MYA) in early Pliocene. These results suggest that barriers and dispersal routes created by the uplift of Brazilian Central Shield and climatic changes explain the diversification and current species distributions of the R. marina group. Dispersal-vicariance analyzes (DIVA) indicated that the two major diversifications of the R. marina group were due to vicariance, although eleven dispersals subsequently occurred. PMID:20813190

Maciel, Natan Medeiros; Collevatti, Rosane Garcia; Colli, Guarino Rinaldi; Schwartz, Elisabeth Ferroni

2010-11-01

 
 
 
 
361

Temperature effects on the biomechanics of prey capture in the frog Rana pipiens.  

Science.gov (United States)

Movements of many animals are powered by a combination of active shortening of muscles and recoil of elastic structures. Movements that rely primarily on elastic recoil, such as the explosive locomotor and feeding movements of many ectotherms, have been shown to exhibit lower thermal dependence than muscle-powered movements because elastically powered movements circumvent the effects of temperature on muscle contractile dynamics. To determine if elastic recoil contributes to the ballistic mouth opening and tongue projection of the frog Rana pipiens, we examined feeding kinematics and dynamics of tongue and jaw movements at three ambient temperatures (10, 15, and 25°C) using 6,000?Hz image sequences. We found that ballistic mouth opening exhibits high instantaneous power (up to 1,783?W?kg(-1) of muscle mass) and its dynamics have low thermal dependence (Q(10) values of 1.02-1.37), indicating the contribution of elastic recoil. The dynamics of tongue projection are more thermally dependent (Q(10) of 1.35-2.51) and likely involve muscle activity during the movement. Mouth opening during prey transport, as well as tongue retraction and mouth closing showed little evidence of elastic recoil and their dynamics show relatively high thermal dependence (Q(10) of 1.38-1.89). R. pipiens shows lower thermal robustness and power of tongue projection than ballistic-tongued Bufo terrestris which displays complete thermal independence, suggesting that in Rana tongue projection is not as tightly coupled to jaw depression as in toads. We propose that thermal experiments may be useful in probing for elastic mechanisms in other biomechanical systems. PMID:22952141

Sandusky, Paula E; Deban, Stephen M

2012-12-01

362

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The amphibians of the pond complex “Stagni di Belangero” in the Po Plain, Asti Province, have been studied. The species living in the pond are Bufo bufo, Bufo viridis, Hyla intermedia, Pelobates fuscus, Rana dalmatina, Rana synklepton esculenta, Rana cf. kurtmuelleri, Triturus carnifex and Triturus vulgaris. Species composition, migration period of P. fuscus, and biometric data are provided. Relevant importance has been given to P. fuscus, since we reconfirm its p...

Fabrizio Li Vigni; Vincenzo Mercurio

2007-01-01

363

The herpetofauna of the north-western region of Bihor County, Romania  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the researched area, we identified a total of 16 species for the herpetofauna. Among these, 11 belong to the amphibians (Triturus vulgaris, Triturus cristatus, Triturus dobrogicus, Bombina bombina, Pelobates fuscus, Bufo bufo, Bufo viridis, Hyla arborea, Rana ridibunda, Rana lessonae, Rana dalmatina) and 5 to the reptiles (Emys orbicularis, Lacerta agilis, Lacerta viridis, Podarcis taurica, Natrix natrix). Aside these 16 species, we also identified populations of Rana kl. esculenta, a hybr...

Covaciu-marcov, Severus-daniel; Bogdan, Horia-vlad; Paina, Cristiana; Toader, Simona; Condure, Natalia

2008-01-01

364

The herpethofauna from the Teuz River hydrographic basin (Arad County, Romania)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the Teuz River hydrographic basin from the western part of Romania we encountered 15 species of amphibians (Salamandra salamandra, Triturus vulgaris, Triturus cristatus, Triturus dobrogicus, Triturus alpestris, Bombina bombina, Bombina variegata, Bufo bufo, Bufo viridis, Hyla arborea, Pelobates fuscus, Rana ridibunda, Rana lessonae, Rana dalmatina, Rana temporaria), 8 species of reptiles (Emys orbicularis, Lacerta agilis, Lacerta viridis, Podarcis muralis, Anguis fragilis, Natrix natrix, C...

Bogdan, H.; Kiss, A.; Sas, I.; Covaciu-marcov, S. D.; St Cicort-lucaciu, A.

2006-01-01

365

Preliminary data regarding the distribution and status of the herpetofauna in Ia?i County (Romania)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents the results of a study conducted in Ia?i County, Romania, an area for which data regarding the distribution of the herpetofauna has previously remained incomplete. Thirteen species of amphibians (Salamandra salamandra, Lissotriton vulgaris, Triturus cristatus, Pelobates fuscus, Hyla arborea, Bombina bombina, Bombina variegata, Bufo bufo, Bufo viridis, Pelophylax ridibundus, Pelophylax lessonae, Rana dalmatina and Rana temporaria), nine reptile species (Emys orbicularis, ...

Strugariu, Alexandru; Zamfirescu, S?tefan R.; Nicoara?, Andreea; Gherghel, Iulian; Sas, Istvan; Pus?cas?u, Cristina M.; Bugeac, Teodor

2008-01-01

366

The herpetofauna of the north-western region of Bihor County, Romania  

Directory of Open Access Journals (Sweden)

Full Text Available In the researched area, we identified a total of 16 species for the herpetofauna. Among these, 11 belong to the amphibians (Triturus vulgaris, Triturus cristatus, Triturus dobrogicus, Bombina bombina, Pelobates fuscus, Bufo bufo, Bufo viridis, Hyla arborea, Rana ridibunda, Rana lessonae, Rana dalmatina and 5 to the reptiles (Emys orbicularis, Lacerta agilis, Lacerta viridis, Podarcis taurica, Natrix natrix. Aside these 16 species, we also identified populations of Rana kl. esculenta, a hybrid form between Rana ridibunda and Rana lessonae.

Severus-Daniel COVACIU-MARCOV

2008-01-01

367

The herpetofauna of the south-western part of Mehedin?i County, Romania  

Digital Repository Infrastructure Vision for European Research (DRIVER)

. The south-western part of Mehedin?i County comprises many herpetofauna species, compared to most regions in Romania. This is how we managed to encounter 14 amphibian species (Salamandra salamandra, Lissotriton vulgaris, Triturus cristatus, Triturus dobrogicus, Bombina bombina, Bombina variegata, Pelobates fuscus, Bufo bufo, Bufo viridis, Hyla arborea, Pelophylax ridibundus, Pelophylax lessonae, Rana dalmatina, Rana temporaria) plus Pelophylax kl. esculentus and 15 reptile species (Emys orb...

Ferent?i, Sara; Sas, Istva?n; Gaceu, Ovidiu; S? Cicort-lucaciu, Alfred; Covaciu-marcov, Severus D.; Bogdan, Horia Vlad

2009-01-01

368

Resumen de las excursiones realizadas a la laguna de La Nava (Fuentes de Nava, Palencia) entre 1950 y 1953, y listado de las especies observadas  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Resumen de las excursiones realizadas a la laguna de La Nava (Fuentes de Nava, Palencia) entre 1950 y 1953, y listado de las especies observadas, entre las que se encuentran los siguientes peces: Barbus sp. (Barbo), Carassius auratus (Pez rojo) y Tinca tinca (Tenca),los siguientes anfibios: Bufo bufo (Sapo común, llamado B.vulgaris por el autor), Epidalea calamita (Sapo corredor, llamado Bufo calamita por el autor), Molge sp. (que seguramente equivale a "Tritón" ,probablemente, Lissotriton ...

Valverde Go?mez, Jose? Antonio

2008-01-01

369

Salida de campo a Orihuela del Tremedal (Teruel) entre el 14 y el 16 de julio de 1952  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Salida de campo del autor y Francisco Bernis a Orihuela del Tremedal, en Teruel, entre el 14 y el 16 de julio de 1952, de la que se anotaron observaciones sobre los siguientes anfibios: Alytes sp. (Sapo partero), Bufo bufo (Sapo común, llamado B.vulgaris por el autor), Epidalea calamita (Sapo corredor, llamado Bufo calamita por el autor) y Hyla sp. (Ranita), los siguientes reptiles: Chalcides sp. (Eslizón, también llamado Eliso por el autor), Podarcis muralis (Lagartija roquera, llamada ...

Valverde Go?mez, Jose? Antonio

2008-01-01

370

Exploring the Genetic Basis of Adaptation to High Elevations in Reptiles: A Comparative Transcriptome Analysis of Two Toad-Headed Agamas (Genus Phrynocephalus)  

Science.gov (United States)

High elevation adaptation offers an excellent study system to understand the genetic basis of adaptive evolution. We acquired transcriptome sequences of two closely related lizards, Phrynocephalus przewalskii from low elevations and P. vlangalii from high elevations. Within a phylogenetic framework, we compared their genomic data along with green anole, chicken and Chinese softshell turtle, and identified candidate genes and functional categories that are potentially linked to adaptation to high elevation environments. More than 100 million sequence reads were generated for each species via Illumina sequencing. A de novo assembly produced 70,919 and 62,118 transcripts for P. przewalskii and P. vlangalii, respectively. Based on a well-established reptile phylogeny, we detected 143 positively selected genes (PSGs) along the P. vlangalii lineage from the 7,012 putative orthologs using a branch-site model. Furthermore, ten GO categories and one KEGG pathway that are over-represented by PSGs were recognized. In addition, 58 GO categories were revealed to have elevated evolutionary rates along the P. vlangalii lineage relative to P. przewalskii. These functional analyses further filter out PSGs that are most likely involved in the adaptation process to high elevations. Among them, ADAM17, MD, and HSP90B1 likely contributed to response to hypoxia, and POLK likely contributed to DNA repair. Many other candidate genes involved in gene expression and metabolism were also identified. Genome-wide scan for candidate genes may serve as the first step to explore the genetic basis of high elevation adaptation. Detailed comparative study and functional verification are needed to solidify any conclusions. High elevation adaptation requires coordinated changes in multiple genes that involve various physiological and biochemical pathways; we hope that our genetic studies will provide useful directions for future physiological or molecular studies in reptiles as well as other poikilothermic species. PMID:25386640

Yang, Weizhao; Qi, Yin; Fu, Jinzhong

2014-01-01

371

Facile synthesis of two diastereomeric indolizidines corresponding to the postulated structure of alkaloid 5,9E-259B from a Bufonid toad (Melanophryniscus  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract A short synthesis of the postulated structure for indolizidine alkaloid 259B with the hydrogens at C5 and C9 entgegen has been achieved with complete control of stereochemistry at C5. Both diastereoisomers at C8 were obtained, but neither proved to be the natural product. The comparison of the mass and FTIR spectral properties of the synthetic compounds to those of the natural material strongly suggest that the gross structure is correct and that the difference may be a branch in the C5 alkyl side-chain. The GC-retention times of the two synthetic compounds were markedly longer than that of the natural 5,9E-259B.

Nelson Angela

2008-01-01

372

Geology and petrography of the basaltic rocks (Arapey formation) cropping out in toad 4 between Arapey river (92 km) and Artigas (200 Km)  

International Nuclear Information System (INIS)

This contribution presents a geological map of the basaltic flows of Arapey formation (Mezosoic) cropping out in Road 4 between the Arapey river (92 Km) and Artigas city (200 Km) together with the description of the petrographic features of the different portions of the 13 recognized flow units. (author)

373

Effects of insecticide formulations used in cotton cultivation in West Africa on the development of flat-backed toad tadpoles (Amietophrynus maculatus).  

Science.gov (United States)

In the West African savanna zone, traditional subsistence farming increasingly shifts to cash crop farming and in particular to cotton cultivation, which is accompanied by application of pesticides. Increasing use of pesticides by smallholder farmers is suspected to have negative effects on non-target organisms. In this study, possible pesticide impact on the development of tadpoles was investigated. Two insecticide formulations used in cotton cultivation in Benin were compared: Cotofan® (active ingredient (a.i.): ?- and ?-endosulfan) and Tihan® (a.i.: spirotetramat and flubendiamide). Tadpoles of the widespread species Amietophrynus maculatus were kept in small water basins with increasing insecticide concentrations (1, 10 and 100 ?g a.i./L) over a period of 28?days. Tadpoles showed reduced survival at the highest endosulfan concentrations (100 ?g/L). Survival of tadpoles undergoing metamorphosis was not influenced by Tihan®. Endosulfan in concentrations of 10 and 100 ?g/L negatively impacted the movement of the tadpoles which was not the case for the mixture of spirotetramat and flubendiamide. Time to metamorphosis was not significantly different in the various treatments. Tail length of tadpoles was significantly shorter in Cotofan® treatments compared to controls. Pesticide residues in the tadpoles were relatively low after keeping them in concentrations of 1 and 10 ?g a.i./L (25 and 26 ?g/kg wet weight (w/w) for the sum of ?-endosulfan, ?-endosulfan and endosulfan sulphate and below the detection limits for flubendiamide and spirotetramat). For the 100 ?g a.i./L treatments, 1,600 ?g/kg w/w was found of ?-endosulfan, ?-endosulfan and endosulfan sulphate together in the survived tadpoles and 21 ?g/kg w/w of flubendiamide. PMID:25192667

Stechert, Christin; Kolb, Marit; Rödel, Mark-Oliver; Bahadir, Müfit

2014-09-01

374

Drug: D06750 [KEGG MEDICUS  

Full Text Available D06750 Crude, Drug Toad venom (JP16) Hellebrin [CPD:C08868], Resibufogenin [CPD:C17058], Cinobuf ... D06750 Toad venom Crude drugs [BR:br08305] Animals Amphibians ... D06750 Toad venom PubChem: 47208401 ...

375

Amphibians of the “Cilento e Vallo di Diano” National Park (Campania, Southern Italy): updated check list, distribution and conservation notes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study, we present the results of our field and bibliographic survey on the amphibians of the “Cilento and Vallo di Diano” National Park (Southern Italy). Two hundred and thirty three spawning sites (167 original and 66 derived from literature), and 11 amphibian species were found. Reproductive activity was recorded for Salamandra salamandra, Salamandrina terdigitata, Triturus carnifex, Lissotriton italicus, Bufo bufo, Hyla i...

Camillo Pignataro; Laura De Riso; Nicola Ventre; Antonio Romano; Cristiano Spilinga

2010-01-01

376

Overwintering without winter: the exceptional case of two terrestrial anurans from the thermal habitats in north-western Romania  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the winter period of December 2006 – February 2007, in the thermal waters from north-western Romania we encountered two terrestrial amphibian species which did not display the hibernation phenomenon: Bufo bufo and Rana temporaria. We hypothesize that the specimens of the two species were dispersing individuals that, being outside their home ranges, were trapped in the thermal ponds in late autumn.

Covaciu-marcov, Severus-daniel; Sas, Istva?n

2007-01-01

377

New effects of Roundup on amphibians: predators reduce herbicide mortality; herbicides induce antipredator morphology.  

Science.gov (United States)

The use of pesticides is important for growing crops and protecting human health by reducing the prevalence of targeted pest species. However, less attention is given to the potential unintended effects on nontarget species, including taxonomic groups that are of current conservation concern. One issue raised in recent years is the potential for pesticides to become more lethal in the presence of predatory cues, a phenomenon observed thus far only in the laboratory. A second issue is whether pesticides can induce unintended trait changes in nontarget species, particularly trait changes that might mimic adaptive responses to natural environmental stressors. Using outdoor mesocosms, I created simple wetland communities containing leaf litter, algae, zooplankton, and three species of tadpoles (wood frogs [Rana sylvatica or Lithobates sylvaticus], leopard frogs [R. pipiens or L. pipiens], and American toads [Bufo americanus or Anaxyrus americanus]). I exposed the communities to a factorial combination of environmentally relevant herbicide concentrations (0, 1, 2, or 3 mg acid equivalents [a.e.]/L of Roundup Original MAX) crossed with three predator-cue treatments (no predators, adult newts [Notophthalmus viridescens], or larval dragonflies [Anax junius]). Without predator cues, mortality rates from Roundup were consistent with past studies. Combined with cues from the most risky predator (i.e., dragonflies), Roundup became less lethal (in direct contrast to past laboratory studies). This reduction in mortality was likely caused by the herbicide stratifying in the water column and predator cues scaring the tadpoles down to the benthos where herbicide concentrations were lower. Even more striking was the discovery that Roundup induced morphological changes in the tadpoles. In wood frog and leopard frog tadpoles, Roundup induced relatively deeper tails in the same direction and of the same magnitude as the adaptive changes induced by dragonfly cues. To my knowledge, this is the first study to show that a pesticide can induce morphological changes in a vertebrate. Moreover, the data suggest that the herbicide might be activating the tadpoles' developmental pathways used for antipredator responses. Collectively, these discoveries suggest that the world's most widely applied herbicide may have much further-reaching effects on nontarget species than previous considered. PMID:22611860

Relyea, Rick A

2012-03-01

378

Preliminary data concerning the distribution of amphibian fauna in Suceava county (Romania  

Directory of Open Access Journals (Sweden)

Full Text Available The present study focused upon an area in which the herpetofauna had previously been very poorly studied and aimed to identify the species of amphibians from the research area and to establish distribution areas. In the 54 investigated localities 16 species of amphibians (Salamandra salamandra, Triturus vulgaris, Triturus cristatus, Triturus alpestris, Triturus montandoni, Pelobates fuscus, Bombina bombina, Bombina variegata, Hyla arborea, Bufo bufo, Bufo viridis, Rana dalmatina, Rana temporaria, Rana arvalis, Rana ridibunda & Rana lessonae and 2 hybrids (Bombina bombina X Bombina variegata & Rana kl. esculanta have been identified. Of these, the Bombina hybrids have been identified for the first time in the studied region.

Alexandru STRUGARIU

2006-05-01

379

Contribution to knowledge of the distribution of herpetofauna in Tarc?u Mountains (Romania  

Directory of Open Access Journals (Sweden)

Full Text Available In the researched area we identified 12 amphibian species: Salamandra salamndra, Lissotritonvulgaris, Triturus cristatus, Mesotriton alpestris, Lissotriton montandoni, Bombina variegata, Bufo bufo,Bufo viridis, Hyla arborea, Pelophylax ridibundus, Rana dalmatina and Rana temporaria and 9 reptilespecies: Lacerta agilis, Lacerta viridis, Zootoca vivipara, Podarcis muralis, Anguis fragilis, Natrix natrix,Zamenis longissimus, Coronella austriaca and Vipera berus. Within the region we identified speciesquoted (Cog?lniceanu et al. 2000, Ghiurc? et al. 2005, Gherghel et al. 2008, Iftime et al. 2008 to havethe lowest altitudinal limit of their spreading area at much higher altitudes. Most of the amphibian andreptilian species are not endangered in the researched area.

Daniel Ghiurc?

2009-12-01

380

Valge fungi uus tulemine / Kersti Pikk  

Index Scriptorium Estoniae

Peeter Tambu projekteeritud valge "eestiaegne" funk eramu, kus avatud planeeringu asemel on paraja suurusega eraldi toad, esikohal ruumide otstarbekus ja ratsionaalsus. Arhitekt on kujundanud interjööri ja mööbli

Pikk, Kersti

2007-01-01

 
 
 
 
381

Moriyama tubamajad väikesele pinnale  

Index Scriptorium Estoniae

Jaapani arhitektid on lahendanud probleemi, kuidas võimal