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Genetic variability in geographic populations of the natterjack toad (Bufo calamita)  

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Across altitudinal and latitudinal gradients, the proportion of suitable habitats varies, influencing the individual dispersal that ultimately can produce differentiation among populations. The natterjack toad (Bufo calamita) is distributed across a wide geographic range that qualifies the species as interesting for a geographic analysis of its genetic variability. Five populations of B. calamita in the Sierra de Gredos (Spain) were studied in an altitudinal gradient ranging from 750 to 2270 ...

2012-01-01

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Quantifying functional connectivity: experimental assessment of boundary permeability for the natterjack toad (Bufo calamita).  

Science.gov (United States)

Like other pond-breeding amphibians, the natterjack toad (Bufo calamita) typically presents a patchy distribution. Because the species experiences high probabilities of local population extinction, its persistence within landscapes relies on both local and landscape-scale processes [dispersal allowing the (re)colonization of habitat patches]. However, the structure and composition of the matrix surrounding local populations can alter the dispersal rates between populations. As shown previously (Landscape Ecol 19:829-842, 2004), the locomotor performances of individuals at the dispersal stage depend on the nature of the component crossed: some landscape components offer high resistance to movement (high resistance or high viscosity components) whereas others allow high efficiency of movement (low resistance components). We now examine the ability of individuals to discriminate between landscape components and select low-resistance components. Our experimental study investigates the ways in which young natterjack toads choose from among landscape components common to southern Belgium. Toadlets (the dispersal stage) were experimentally confronted with boundaries between surrogates of sandy soils, roads, forests, agricultural fields and intensive pastures. Our results show: 1 the ability of toadlets to react to boundaries between landscape components, 2 differences in permeability among boundaries, and 3 our inability to predict correctly the permeability of the boundaries from the patch-specific resistance assessed previously. Toadlets showed a preference for bare environments and forests, whereas they avoided the use of agricultural environments. This pattern could not be explained in terms of patch-specific resistance only, and is discussed in terms of mortality risks and resource availability in the various landscape components, with particular attention to repercussions on conservation strategies. PMID:16896772

Stevens, Virginie M; Leboulengé, Eric; Wesselingh, Renate A; Baguette, Michel

2006-11-01

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Genetic variability in geographic populations of the natterjack toad (Bufo calamita).  

Science.gov (United States)

Across altitudinal and latitudinal gradients, the proportion of suitable habitats varies, influencing the individual dispersal that ultimately can produce differentiation among populations. The natterjack toad (Bufo calamita) is distributed across a wide geographic range that qualifies the species as interesting for a geographic analysis of its genetic variability. Five populations of B. calamita in the Sierra de Gredos (Spain) were studied in an altitudinal gradient ranging from 750 to 2270 m using microsatellite markers. In addition, we analyzed the latitudinal genetic variation in B. calamita within a global European distribution using genetic diversity parameters (mean number of alleles per locus [M(a)] and expected heterozygosity [H(E)]) obtained from our results and those published in the literature. The low level of genetic differentiation found between populations of B. calamita (F(st) ranging from 0.0115 to 0.1018) and the decreases in genetic diversity with altitude (M(a) from 13.6 to 8.3, H(E) from 0.82 to 0.74) can be interpreted by the combined effects of discontinuous habitat, produced mainly by the high slopes barriers and geographic distance. In the latitudinal gradient, genetic diversity decreases from south to north as a consequence of the colonization of the species from the Pleistocene refugium. We conclude that the genetic variability in B. calamita along its wide altitudinal and latitudinal geographic distribution mainly reflects the colonization history of the species after the last glacial period. PMID:22957202

Oromi, N; Richter-Boix, A; Sanuy, D; Fibla, J

2012-08-01

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The effects of selection, drift and genetic variation on life-history trait divergence among insular populations of natterjack toad, Bufo calamita.  

Science.gov (United States)

Although loss of genetic variation is frequently assumed to be associated with loss of adaptive potential, only few studies have examined adaptation in populations with little genetic variation. On the Swedish west coast, the northern fringe populations of the natterjack toad Bufo calamita inhabit an atypical habitat consisting of offshore rock islands. There are strong among-population differences in the amount of neutral genetic variation, making this system suitable for studies on mechanisms of trait divergence along a gradient of within-population genetic variation. In this study, we examined the mechanisms of population divergence using Q(ST)-F(ST) comparisons and correlations between quantitative and neutral genetic variation. Our results suggest drift or weak stabilizing selection across the six populations included in this study, as indicated by low Q(ST)-F(ST) values, lack of significant population x temperature interactions and lack of significant differences among the islands in breeding pond size. The six populations included in this study differed in both neutral and quantitative genetic variation. Also, the correlations between neutral and quantitative genetic variation tended to be positive, however, the relatively small number of populations prevents any strong conclusions based on these correlations. Contrary to the majority of Q(ST)-F(ST) comparisons, our results suggest drift or weak stabilizing selection across the examined populations. Furthermore, the low heritability of fitness-related traits may limit evolutionary responses in some of the populations. PMID:20465584

Rogell, Björn; Eklund, Martin; Thörngren, Hanna; Laurila, Anssi; Höglund, Jacob

2010-06-01

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Gene flow and functional connectivity in the natterjack toad.  

Science.gov (United States)

Functional connectivity is a key factor for the persistence of many specialist species in fragmented landscapes. However, connectivity estimates have rarely been validated by the observation of dispersal movements. In this study, we estimated functional connectivity of a real landscape by modelling dispersal for the endangered natterjack toad (Bufo calamita) using cost distance. Cost distance allows the evaluation of 'effective distances', which are distances corrected for the costs involved in moving between habitat patches in spatially explicit landscapes. We parameterized cost-distance models using the results of our previous experimental investigation of natterjack's movement behaviour. These model predictions (connectivity estimates from the GIS study) were then confronted to genetic-based dispersal rates between natterjack populations in the same landscape using Mantel tests. Dispersal rates between the populations were inferred from variation at six microsatellite loci. Based on these results, we conclude that matrix structure has a strong effect on dispersal rates. Moreover, we found that cost distances generated by habitat preferences explained dispersal rates better than did the Euclidian distances, or the connectivity estimate based on patch-specific resistances (patch viscosity). This study is a clear example of how landscape genetics can validate operational functional connectivity estimates. PMID:16842409

Stevens, Virginie M; Verkenne, Catherine; Vandewoestijne, Sofie; Wesselingh, Renate A; Baguette, Michel

2006-08-01

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Importance of habitat quality and landscape connectivity for the persistence of endangered natterjack toads.  

Science.gov (United States)

The natterjack toad (Bufo calamita) is endangered in several parts of its distribution, including Belgium, where it occurs mainly in artificial habitats. We parameterized a general model for natterjack population viability analysis (PVA) and tested its sensitivity to changes in the values of basic parameters. Then we assessed the relative efficiency of various conservation measures in 2 situations: a small isolated population and a system of 4 populations connected by rare dispersal movements. We based the population viability analysis on a stage-structured model of natterjack population dynamics. We parameterized the model in the RAMAS GIS platform with vital rates obtained from our own field experience and from published studies. Simulated natterjack populations were highly sensitive to habitat quality (particularly pond drying), to dispersal from surrounding local populations, and to a lesser extent to values of fecundity and survival of terrestrial stages. Population trajectories were nearly insensitive to initial abundances, carrying capacities, and the frequency of extreme climatic conditions. The simulations showed that in habitats with highly ephemeral ponds, where premetamorphosis mortality was high, natterjack populations nearly always had a very high extinction risk. We also illustrated how low dispersal rates (<1 dispersing individual/generation) efficiently rescued declining local populations. Such source-sink dynamics demonstrate that the identification and management of source populations should be a high priority. PMID:18680506

Stevens, Virginie M; Baguette, Michel

2008-10-01

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Phenotypic selection in common toad (Bufo bufo  

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Full Text Available One of the most important problems for evolutionary biologists is to investigate the patterns and strength of phenotypic selection acting on quantitative traits in natural populations. Measurement of selection is complicated by the presence of correlations between characters; selection on a particular trait produces not only a direct effect, but indirect effects as well. Despite the growing body of phenotypic selection studies in a variety of taxa, studies on amphibians are still sparse. The aim of this study was to estimate patterns and strength of selection acting on a set of correlated characters in a natural population of Bufo bufo from the vicinity of Belgrade, Serbia. Morphological traits (body length, fore- and hind leg length were measured, while fitness was assayed as fecundity and gonad weight for females and males, respec­tively. The regression approach was used to estimate selection differentials and gradients. Selection patterns differed between the sexes - linear selection differentials showed significant total directional selection for body size in females, but not in males. In males, differentials were significant for both fore- and hind leg lengths. Sample size did not permit identification of significant nonlinear (quadratic selection.

Cvetkovi? Dragana

2007-01-01

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Progressive Skinning of Toads (Bufo bufo by the Eurasian Otter (Lutra lutra  

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Full Text Available Predation of the Common Toad (Bufo bufo by otters is less common than predation of the Common Frog (Rana temporaria. To avoid the paratoid glands of toads, only the hind legs may be skinned and eaten. At a B. bufo breeding site, regularly predated by otters, an increasing proportion of predated toads have been completely skinned. With declining populations of fish and crustacean prey, it is suggested that this apparent behavioural change better utilises the residual food resource.

Slater F.

2002-04-01

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1987-03-01

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

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

Fernández-Palacios, O´Connor, Rocío

2009-04-01

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An Extraordinary New Toad (Bufo ttom Costa Rica  

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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

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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.

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Evaluating factors affecting amphibian mortality on roads: the case of the Common Toad Bufo bufo, near a breeding place  

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Full Text Available The Common Toad Bufo bufo is the amphibian with the highest rates of road mortality in many European countries. This elevated incidence of road kills has frequently been associated with migration to breeding sites. In this study, we analysed the mortality of the Common Toad in the road network in Catalonia (NE Spain, and investigated the related causative factors on four roads near a breeding site in the Pyrenees. Results suggest that the high mortality rate is due to a combination of factors: toad abundance, traffic density and quality of water bodies for breeding. On the road with the highest incidence of road kills we investigated whether deaths occurred at specific spots or in a random manner. The road was divided into 500 m sections and each section was classified according to biotic (type of vegetation and abiotic (presence of streams, roadside topography variables. Multiple correspondence analysis showed that sections with streams crossing under the road had the highest mortality rate, suggesting that such water bodies flowing into the breeding pond are the toads' main migratory pathways for hibernation and breeding. As toads use the same migratory routes each year, it is critical to identify areas with a high potential mortality so that efficient measures can be designed to increase wildlife permeability, and thereby reduce habitat fragmentation. This methodology could be applied in other areas with high amphibian mortality.

N. Garriga

2007-01-01

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

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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

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Seasonal and daily plasma corticosterone rhythms in American toads, Bufo americanus  

International Nuclear Information System (INIS)

Concentrations of corticosterone were measured in the plasma of American toads, Bufo americanus, on a seasonal basis using a radioimmunoassay technique. Two populations of toads, maintained under different light conditions, were monitored to observe the effects of photoperiod on the seasonal rhythm of plasma corticosterone. Under a natural photoperiod toads demonstrated a rhythm consisting of a spring peak and a fall peak in corticosterone concentration. Toads maintained under a 12L:12D photoperiod all year round demonstrated a similar rhythm with peaks in the spring and fall. This suggests that an endogenous (circannual) rhythm of corticosterone may be playing an important role in the seasonal change of overt behavior and physiology of Bufo americanus. A daily rhythm of corticosterone was also detected in toads when blood samples were taken every 4 hr. When compared to a previously published circadian rhythm study of locomotor activity, the surge in corticosterone concentration for the day occurred at 1730 just prior to the peak in locomotor activity

1983-01-01

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Seasonal and daily plasma corticosterone rhythms in American toads, Bufo americanus  

Energy Technology Data Exchange (ETDEWEB)

Concentrations of corticosterone were measured in the plasma of American toads, Bufo americanus, on a seasonal basis using a radioimmunoassay technique. Two populations of toads, maintained under different light conditions, were monitored to observe the effects of photoperiod on the seasonal rhythm of plasma corticosterone. Under a natural photoperiod toads demonstrated a rhythm consisting of a spring peak and a fall peak in corticosterone concentration. Toads maintained under a 12L:12D photoperiod all year round demonstrated a similar rhythm with peaks in the spring and fall. This suggests that an endogenous (circannual) rhythm of corticosterone may be playing an important role in the seasonal change of overt behavior and physiology of Bufo americanus. A daily rhythm of corticosterone was also detected in toads when blood samples were taken every 4 hr. When compared to a previously published circadian rhythm study of locomotor activity, the surge in corticosterone concentration for the day occurred at 1730 just prior to the peak in locomotor activity.

Pancak, M.K.; Taylor, D.H.

1983-06-01

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Advertisemente calls of cuban toads of the genus Bufo (Anura, Bufonidae  

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Full Text Available The Bufo peltocephalus group is comprised of ten species of toads from the West Indies. Cuba hosts the highest diversity, with a total of seven endemic species. Adequated acoustic characterization of the vocalizations remained absent for the majority of these species. We offer some natural history data on their calling behavior, calling/breeding sites and describe the spectral and temporal characteristics of the advertisement call for all seven Cuban toads, five of wich have no been described. The calls of each species differ from the rest in at least two of the examined parameters, particulary in dominant frequency and pulse rate. We observed two basic patterns of amplitude modulation. The first one, emitted from the three largest toad species, is characterized by long calls with trains of complex pulses. The second pattern, typical of the small and the intermediate size species, includes short calls with trains of simple pulses.

Roberto Alonso

2003-12-01

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[Cardiotropic activity of total bufadienolides from the poison of Central Asian toad Bufo viridis].  

Science.gov (United States)

The sum of bufadienolides (bacagin) isolated from the poison of Bufo viridis toad occurring in Central Asia produces a selective strophanthin-K-like action upon the heart function, increasing myocardial contractility, retarding cardiac rhythm, and positively influencing the parameters of myocardial metabolism. The mechanism of realization of the positive ionotropic effect of bacagin is probably related to the ability of increasing the basal level of cytosol calcium at the expense of inhibiting the activity of Na+/K(+)-ATPase and, to some extent, Ca(2+)-ATPase in endoplasmic reticulum. PMID:12449070

Usanova, I V; Khushbaktova, Z A; Syrov, V N; Azizov, D E; Mirzaakhmedov, Sh Ia; Soliev, A B; Tashmukhamedov, M S; Salikhov, Sh I

2002-01-01

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

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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

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Basal and amiloride-induced short-circuit current across isolated toad skin (Bufo arenarum).  

Science.gov (United States)

We have previously demonstrated that amiloride (amil) addition to the isolated ventral pelvic (VPel) skin of Bufo arenarum toad induces negative short-circuit current values, which are equivalent to the isotopically measured net chloride transport. In the present work, we found that exposure of various regions of toad skin to amil yielded different values of short-circuit current (aSCC): negative aSCC was found in the VPel and ventral pectoral skin, while those of the dorsal one were not different from zero. The distinct values of aSCC found show a regional difference in the active chloride absorption, probably related to postural adaptations. A possible role of this adaptation would be related to chloride participation in the saline balance of the animals, or the maintenance of epithelial integrity. PMID:3141246

Soria, M O; Berman, D M; Coviello, A

1988-08-01

 
 
 
 
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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 gonadotropins in plasma samples of Bufo japonicus. (author)

1989-01-01

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

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

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

2009-01-01

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Progesterone improves the number and quality of hormone induced Fowler toad (Bufo fowleri oocytes  

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Full Text Available Abstract Combinations of progesterone, lutenizing hormone releasing hormone analogue (LHRHa, human chorionic gonadotrophin (hCG, and the dopamine-2 (DA2 receptor antagonist 1-[1-[4,4-bis(4-Fluorophenylbutyl]-4-piperidinyl]-1,3-dihydro-2H-benzimidazol-2-one (Pimozide; Orap were tested for improvement of spawning rates, oocyte numbers, fertilization and neurulation rates of the Fowler toad (Bufo fowleri. Only treatments combined with progesterone produced large numbers of oocytes. The best treatment on oocyte numbers, neurulation rates, and the number of neurulas was with 5 mg progesterone, 20 mic.g LHRHa, and 0.25 mg Pimozide. Progesterone (5 mg with 60 mic.g LHRHa gave high spawning rates, oocyte numbers, and fertilization rates but neurulation rates were low. Progesterone alone in high repeated doses did not result in ovulation. High doses of LHRHa (60 mic.g with hCG, progesterone, and Pimozide gave the greatest number of toads spawning, however, they resulted in low oocyte numbers, fertilization and neurulation rates. A low dose of LHRHa (4 mic.g with hCG, or hCG alone as a second administration, and progesterone with Pimozide produced few good quality oocytes. Toads were given normal ovulatory doses of hormones 24 or 48 hrs after their initial dose, but these resulted in low oocyte numbers followed by poor fertilization. Overall, these results suggest that progesterone with a dose between 20 mic.g and 60 mic.g of LHRHa may be optimal for the induction of ovulation in these toads. Moreover, Pimozide can supplement low doses of LHRHa but not replace it.

Li Hong

2006-02-01

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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

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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

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Morphology and distribution of Müller cells in the retina of the toad Bufo marinus.  

Science.gov (United States)

We have previously shown that an antibody against neuron-specific enolase (NSE) selectively labels Müller cells (MCs) in the anuran retina (Wilhelm et al. 1992). In the present study the light- and electron-microscopic morphology of MCs and their distribution were described in the retina of the toad, Bufo marinus, using the above antibody. The somata of MCs were located in the proximal part of the inner nuclear layer and were interconnected with each other by their processes. The MCs were uniformly distributed across the retina with an average density of 1500 cells/mm2. Processes of MCs encircled the somata of photoreceptor cells isolating them from each other by glial sheath, except for those of the double cones. Some of the photoreceptor pedicles remained free of glial sheath. Electron-microscopic observations confirmed that MC processes provide an extensive scaffolding across the neural retina. At the outer border of the ganglion cell layer these processes formed a non-continuous sheath. The MC processes traversed through the ganglion cell layer and spread beneath it between the neuronal somata and the underlying optic axons. These processes formed a continuous inner limiting membrane separating the optic fibre layer from the vitreous tissue. Neither astrocytic nor oligodendrocytic elements were found in the optic fibre layer. The significance of the uniform MC distribution and the functional implications of the observed pattern of MC scaffolding are discussed. PMID:8481951

Gábriel, R; Wilhelm, M; Straznicky, C

1993-04-01

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Isolation and characterization of iridoviruses from the giant toad Bufo marinus in Venezuela.  

Science.gov (United States)

In this communication we describe for the first time the isolation of 7 iridoviruses from the toad Bufo marinus and an unknown species of frog Leptodactylus in Venezuela, South America. The viruses are icosahedral with electron-dense cores, each of which is surrounded by an inner membrane, capsid and a cell-derived envelope. The virus(es) have an average vertex to vertex diameter of 160 nm and replicate in the cytoplasm of a range of cell lines. Within the cytoplasm of infected cells, rarefied areas could be observed; structures lacked cellular organelles and contained complete, empty and developing viruses. Results from antigen-capture enzyme-linked immunosorbent assays (ELISA) with polyclonal antibody raised against epizootic haematopoietic necrosis virus (EHNV) indicated cross-reactivity between these isolates, Bohle iridovirus (BIV) and frog virus 3 (FV3). Comparison of polypeptide and genomic profiles indicated that the Venezuelan viruses shared many polypeptides of equivalent molecular weight with type species FV3. There were, however, differences between the group of Venezuelan viruses and FV3 and BIV. The viruses belongs to the family Iridoviridae and the genus Ranavirus. PMID:9653454

Zupanovic, Z; Musso, C; Lopez, G; Louriero, C L; Hyatt, A D; Hengstberger, S; Robinson, A J

1998-05-14

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An improved enzyme linked immunosorbent assay for detection of anti-ranavirus antibodies in the serum of the giant toad (Bufo marinus).  

Science.gov (United States)

An improved ranavirus antibody ELISA (R Ab ELISA) for the specific detection of anti-ranavirus antibodies in toad sera was developed. Sheep anti-epizootic haematopoietic necrosis virus (EHNV) was used as the antigen-capture antibody. EHNV was used as the antigen and sera from field and challenged toads were used to detect the virus. Rabbit anti-toad IgG and IgM were used to detect bound toad antibody. Pre-absorption of toad sera with a monoclonal antibody, raised against the 50 kDa EHNV protein, improved the specificity of the technique. A blocking ELISA, immunofluorescence and immuno-electron microscopy were used to confirm the validity of the ELISA. The assay has potential use in screening sera from Bufo marinus for the presence of antibodies against ranaviruses and to facilitate understanding of the humoral immunological response in toads during virus infection. PMID:9877438

Zupanovic, Z; Lopez, G; Hyatt, A; Shiell, B J; Robinson, A J

1998-01-01

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

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Full Text Available 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. Consequently, we tested the efficacy of a combination of human Chorionic Gonadotrophin (hCG and Luteinizing Hormone Releasing Hormone analogue (LHRHa administered as one dose, or two or three sequential doses to Bufo baxteri on egg numbers, fertilization and early embryo development. Spawning toads deposited eggs into Simplified Amphibian Ringers (SAR solution to enable controlled in-vitro fertilization (IVF with sperm from hormonally induced male toads. Unprimed females receiving a single mixed normally ovulatory dose of 500 IU hCG plus 4 micrograms of LHRHa produced no eggs. Whereas females primed with this dose and an anovulatory dose (100 IU hCG and 0.8 micrograms of LHRHa of the same hormones, or primed only with an anovulatory dose, spawned after then receiving an ovulatory dose. Higher total egg numbers were produced with two primings than with one priming. Moreover, two primings produced significantly more eggs from each individual female than one priming. The cleavage rate of eggs was not found to differ between one or two primings. Nevertheless, embryo development with eggs from two primings gave a significantly greater percentage neurulation and swim-up than those from one priming. Of the male toads receiving a single dose of 300 IU hCG, 80% produced spermic urine with the greatest sperm concentration 7 hours post-administration (PA. However, peak sperm motility (95% was achieved at 5 hours PA and remained relatively constant until declining 20 hours PA. In conclusion, Bufo baxteri egg numbers and quality benefited from sequential priming with LHRHa and hCG whereas spermic urine for IVF was produced from males with a single dose of hCG. The power of assisted reproduction technology in the conservation of endangered amphibians is shown by the release of nearly 2000 tadpoles produced by IVF during this study.

Seratt Jessica

2006-06-01

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Visual performance of the toad (bufo bufo) at low light levels: Retinal ganglion cell responses and prey-catching accuracy  

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Abstract The accuracy of toad snapping towards moving worm dummies under various levels of dim illumination (from absolute threshold to moonlight) was videorecorded and related to spike responses of retinal ganglion cells exposed to equivalent stimuli. Some toads (at ca. 16 °C) successfully snapped at dummies that produced only one photoisomerization per 50 rods per second in the retina, in good agreement with thresholds of sensitive retinal ganglion cells. One factor underlying such high s...

Aho, A. -c; Donner, K.; Helenius, S.; Larsen, L. O.; Reuter, T.

1993-01-01

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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

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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

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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 environmental exposure to coal combustion wastes interact to decrease survival in larval amphibians.

2012-05-01

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

Science.gov (United States)

Cloacal swabs and caecal contents sampled from 58 cane toads (Bufo marinus) in St George's parish, Grenada, during a 7-month period in 2011 were examined by an enrichment and selective culture method for presence of Salmonella spp. Twenty-four (41%) toads were positive for Salmonella spp. of which eight were Salmonella enterica serovar Javiana, and eight were S. enterica serovar Rubislaw. The other serovars were as follows: Montevideo, 6; Arechavaleta, 1; and serovar: IV:43:-:-, 1. The high frequency of isolation of serovar Javiana, an emerging human pathogen associated with several outbreaks in the recent years in the eastern United States, suggests a possible role for cane toads in transmission of this serovar. Although S. Rubislaw has been isolated from lizards, bats and cases of some human infections, there is no report of its carriage by cane toads, and in such high frequency. The rate of carriage of S. Montevideo, a cause for human foodborne outbreaks around the world was also over 10% in the 58 toads sampled in this study. The antimicrobial drug susceptibility tests against amoxicillin-clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, imipenem, nalidixic acid, streptomycin, tetracycline and trimethoprim-sulfamethoxazole showed that drug resistance is minimal and is of little concern. Antimicrobial resistance was limited to ampicillin and amoxicillin-clavulanic acid in one isolate of S. Javiana and one isolate of S. Rubislaw. This is the first report of isolation and antimicrobial susceptibilities of various Salmonella serovars not identified previously in cane toads in Grenada, West Indies. PMID:23035820

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

2013-09-01

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Effect of neuropeptide-Y and galanin on autonomic control of heart rate in the toad, Bufo marinus.  

Science.gov (United States)

The effects of neuropeptide-Y (NPY) and galanin (GAL) on the autonomic control of heart rate were investigated in the anaesthetised toad, Bufo marinus. Both vagosympathetic trunks were sectioned to prevent reflex changes in heart rate, and the cardiac responses to electrical stimulation of either the vagal or sympathetic fibres to the heart assessed. Intravenous, bolus doses of 10 or 20 micrograms (2 or 4 nmol) NPY and 5 or 10 micrograms (1.5 or 3 nmol) GAL caused pronounced pressor responses but small direct changes in heart rate. Pulse intervals measured after peptide administration were within 5% of control values. All doses of both peptides caused inhibition of action of the cardiac vagus nerves, the maximum inhibition observed in response to 20 micrograms NPY: mean 49.5 +/- 14% (SEM). No significant changes in cardiac sympathetic nerve action were observed. It is concluded that NPY and GAL have similar, important cardiovascular actions in the toad. Similarities between the responses of toads and mammals to NPY suggest a phylogenetic conservation of function for this peptide. PMID:1717535

Courtice, G P

1991-05-01

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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  

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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)...

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

2006-01-01

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

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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 addit...

Mesut Sahin; Erdal Balcan

2006-01-01

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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

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Comparative Fine Structural Studies on the Adrenal Glands of the Toad, (Bufo tibamicus and the Desert Reptile, (Uromastyx philbyi  

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Full Text Available fine structure of adrenal gland in the toad, (Bufo tibamicus and the desert reptile, (Uromastyx philbyi. The adrenal glands of both animals are composed of adrenocortical and chromaffin tissues. In B. tibamicus, The adrenocortical tissue is comprised of two main types of cells, the steroid cells with abundance of lipid inclusions and eosinophilic cells with eosinophilic granular cytoplasm. The chromaffin tissue is intermingled with adrenocortical tissue. They are formed of adrenaline and nor-adrenaline secreting cells with different electron density and variable sizes. The adrenocortical cells of U. phiblyi constituent the main bulk of the inner gland and they are typical steroid-secreting cells. They also characterized by their rich amount of lipid droplets. Cords or islets of inner chromaffin cells are scattered throughout the adrenocortical cells. The outer portion of the gland is composed of chromaffin cells surrounded by the capsule. Adrenaline and nor-adrenaline secreting cells were distinguished by means of different electron density of their chromaffin granules either in the outer or inner portion of the gland.

S. A. Sakr

2001-01-01

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

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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

 
 
 
 
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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.

42

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

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

Wen Chen

2007-01-01

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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 on hibernating amphibians depends on cadmium concentration and soil composition and moisture

2004-12-01

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

Energy Technology Data Exchange (ETDEWEB)

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

Lee, Yook Heng; Stuebing, R.B. (Univ. Kebangsaan Malaysia, Sabah (Malaysia))

1990-08-01

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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

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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  

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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.

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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  

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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

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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.  

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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 ( 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

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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  

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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

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Age and Growth of the Green Toad, Bufo viridis (Laurenti, 1768) from an Island and a Mainland Population in Giresun, Turkey  

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Age structure and some growth parameters of Bufo viridis from the Giresun Island and Giresun province in Turkey were studied by skeletochronology. We studied 56 specimens (41 female, 15 male) from island and 44 (5 female, 39 male) from mainland population. In both populations, age at sexual maturity was 2-3 years in both males and females. Age was ranged from 2-8 years for females and 3-6 years for males in island while 4-7 and 3-8 years in mainland population, respectively. Males and ...

Bilal Kutrup; Emel Cakir; Zeliha Colak; Ufuk Bulbul; Handan Karaoglu

2011-01-01

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The Use of Swiss Albino Mice and Egyptian Toads (Bufo regularis as Reliable Biological Test Animals for Screening Chemicals and Drugs Which Induce Leukaemia in Man. I: The Effect of Nizoral (Ketoconazole on Leucocytes of Toads and Mice  

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Full Text Available Nizoral (Ketoconazole is an antifungal drug used for the treatment of systemic mycosis and mucocutaneous candidiasis. Administration of Nizoral into toads and mice induced pronounced alterations in leucocytes. Electron microscopical examination revealed that these alterations are leukaemic alterations and they are more or less similar to the criteria reported in human Leukaemia. The changes were all comparable to those observed after the administration of the carcinogenic chemical 7,12 dimethylbenz (a anthracene.

M.M. El-Mofty

2000-01-01

52

The Use of Swiss Albino Mice and Egyptian Toads (Bufo regularis) as Reliable Biological Test Animals for Screening Chemicals and Drugs Which Induce Leukaemia in Man. I: The Effect of Nizoral (Ketoconazole) on Leucocytes of Toads and Mice  

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Nizoral (Ketoconazole) is an antifungal drug used for the treatment of systemic mycosis and mucocutaneous candidiasis. Administration of Nizoral into toads and mice induced pronounced alterations in leucocytes. Electron microscopical examination revealed that these alterations are leukaemic alterations and they are more or less similar to the criteria reported in human Leukaemia. The changes were all comparable to those observed after the administration of the carcinogenic chemical 7,12 dimet...

El-mofty, M. M.; Essawy, A. E.; Shwairebv, M. H.; Abdel-karim, H. M.

2000-01-01

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Effects of temperature and general anesthesia on the water gain and the inulin space of the brain of the toad, Bufo arenarum Hensel.  

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1. The water gain in vitro and the inulin space of the brain of the toad were measured under different experimental conditions. 2. There exists a highly positive correlation between water uptake by the brain and the acclimation-incubation temperature, 7 degrees-37 degrees C. 3. Regional differences in the water gain and inulin space were also demonstrated when measured at 20 degrees C. Higher gains were observed in hemispheres, mesodiencephalon and rhombencephalon. 4. The water gain was higher for whole brains obtained under deep anesthesia with ether or urethane but not under nembutal. The inulin space was also higher under ether but lower under urethane. Nembutal had no effect in this case either. 5. A hypothesis about the possible role of water and electrolyte movements in the mechanism of action of some general anesthetics is advanced. PMID:2893687

Segura, E T; Varsavsky, A; Petriella, S

1987-01-01

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Table 4  

…Species Amphibians Great Crested Newt (Triturus cristatus) Natterjack Toad (Bufo calamita) Beetles A diving beetle (Bidessus unistratus) Flixweed flea beetle (psylliodes sophiae) Birds Skylark (Alauda arvensis) Bittern (Botaurus stellaris) Stone Curlew (Burhinus oedicnemus) Nightjar (Caprimulgus europaeus…

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Table 4  

…Crested Newt (Triturus cristatus) Natterjack Toad (Bufo calamita) Beetles A diving beetle (Bidessus unistratus) Flixweed flea beetle (psylliodes sophiae) Birds Skylark (Alauda arvensis) Bittern (Botaurus stellaris) Stone Curlew (Burhinus oedicnemus) Nightjar (Caprimulgus europaeus) Woodlark (Lullula…

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

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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

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Osteological peculiarities of Bufo brongersmai (Anura: Bufonidae) and their possible relation to life in an arid environment  

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Osteological peculiarities of Bufo brongersmai (Anura: Bufonidae) and their possible relation to life in an arid environment. Zoological Studies 48(1): 108-119. The morphology of selected isolated skeletal elements of the northwestern African endemic toad Bufo brongersmai Hoogmoed 1972 is herein described and compared to those of other Bufo species inhabiting the same area and Europe. The osteological morphology of this species clearly differentiates it from others within the genus, and sever...

Delfino, M.; Doglio, S.; Roc?ek, Z.; Seglie, D.; Kabiri, L.

2009-01-01

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Effect of Fish Oil on Liver Tumorigenesis and Biochemical Perturbations in Toads Treated with 7,12-Dimethylbenz (a) anthracene  

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The effect of fish oil on 7,12-dimethylbenz(a) anthracene (DMBA) - induced liver tumors in toads Bufo regularis was investigated. Feeding toads with DMBA 0.5 mg/toad twice weekly for 14 weeks, induced liver tumors (hepatocellular carcinomas) in 32 % of the treated animals. No tumors were detected in toads received DMBA plus 0.1 ml fish oil. Biochemical estimation of several parameters; total lipids, cholesterol, triglycerides, glutamic pyruvic acid transaminase (GPT) and glutami...

Sadek, Ismail A.; Ghazaly, Kamal S.; Essawy, Amina E.; Al-attar, Atef M.

2002-01-01

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Assessment of age and intersexual size differences in Bufo bufo  

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Full Text Available Numerous studies have underlined the complex nature of relationship between age, size, and reproductive traits in anurans. One of the most intriguing problems for evolutionary biologists is intersexual difference in body size (SSD. For testing various hypotheses about SSD, we need reliable estimates of its extent (the important issue being the choice of trait for analysis as well as the accurate determination of individual age. The measures of SSD may be subject to error if estimated from populations with unknown age distribution; amphibians continue to grow throughout their life and SSD is linked to sex differences in traits such as age at maturity and lifespan. In the present paper, we analyze problems involved in accurate determination of age structure and factors that may lead to under- or overestimation of individual age, as well as the problem of appropriate choice of traits, in the light of our experience and results of investigating populations of common toad (Bufo bufo in the vicinity of Belgrade.

Cvetkovi? Dragana D.

2005-01-01

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

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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

2013-05-15

 
 
 
 
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Offspring of Sex-reversed Males in Bufo viridis LAUR  

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In order to determine the sex-determining mechanism in Bufo viridis, males were sex-reversed into females by castration and subsequent administration with estrogen, and mated with normal males to obtain the offspring. Of the 25 castrated and estrogen-injected males, 17 lived for more than 15 months. While seven of these toads had regenerated testes and normal BIDDER'S organs, the other ten had well-developed ovaries transformed from their BIDDER'S organs, although the oviducts were defective ...

Ueda, Hiroaki

2006-01-01

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

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

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

2007-01-01

63

Detection of antibodies against iridoviruses in the serum of the amphibian Bufo marinus.  

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Sera from the amphibian Bufo marinus (cane or marine toad) were investigated using a newly-developed enzyme-linked immunosorbent assay for the detection of antibodies to ranaviruses (Family Iridoviridae). Epizootic haematopoietic necrosis virus (EHNV) or Bohle iridovirus (BIV) was affinity purified from cell culture supernatants and simultaneously bound to the solid phase using specific linker antibodies. After binding to antigen, antibodies in Bufo marinus serum were then detected with a specific anti-immunoglobulin reagent. Of 21 Bufo marinus sera, 3 contained antibodies against EHNV, BIV or related viruses in the ranavirus group, at titres greater than 3200. Reactivity of cane toad antibodies against BIV, an amphibian virus, was greater than that against similar concentrations of EHNV, a piscine virus. PMID:9395145

Whittington, R J; Kearns, C; Speare, R

1997-10-01

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Infestação de Amblyomma rotundatum (Koch (Acari, Ixodidae em sapos Bufo ictericus (Spix (Amphibia, Bufonidae: novo registro de hospedeiro Infestation of Amblyomma rotundatum (Koch (Acari, Ixodidae ticks on Bufo ictericus (Spix (Amphibia, Bufonidae: new host record  

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Full Text Available Bufo ictericus Spix, 1824 toad population (N = 125 foraging in lighted areas in the Corupá Municipality, Santa Catarina State, was surveyed to evaluate the prevalence (percentage of infestation and the mean infestation intensity of Amblyomma rotundatum Koch, 1844 (Acari, Ixodidae ticks. The prevalence was of 19.2% and the mean infestation intensity was 7.4 ticks per infested toad. For the first time B. ictericus as host of A. rotundatum is reported.

Germano Woehl Jr.

2002-06-01

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Effect of Fish Oil on Liver Tumorigenesis and Biochemical Perturbations in Toads Treated with 7,12-Dimethylbenz (a anthracene  

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Full Text Available The effect of fish oil on 7,12-dimethylbenz(a anthracene (DMBA - induced liver tumors in toads Bufo regularis was investigated. Feeding toads with DMBA 0.5 mg/toad twice weekly for 14 weeks, induced liver tumors (hepatocellular carcinomas in 32 % of the treated animals. No tumors were detected in toads received DMBA plus 0.1 ml fish oil. Biochemical estimation of several parameters; total lipids, cholesterol, triglycerides, glutamic pyruvic acid transaminase (GPT and glutamic oxaloacetic acid transaminase (GOT, demonstrated a significant effects of fish oil on the alterations induced by DMBA. The obtained results collectively revealed the anticancer activity of fish oil as well as its pronounced ameliorative effect against the toxic effects of DMBA on the haematochemical parameters in toads Bufo regularis.

Ismail A. Sadek

2002-01-01

66

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

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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

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An invasive species induces rapid adaptive change in a native predator: cane toads and black snakes in Australia  

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Rapid environmental change due to human activities has increased rates of extinction, but some species may be able to adapt rapidly enough to deal with such changes. Our studies of feeding behaviour and physiological resistance to toxins reveal surprisingly rapid adaptive responses in Australian black snakes (Pseudechis porphyriacus) following the invasion of a lethally toxic prey item, the cane toad (Bufo marinus). Snakes from toad-exposed localities showed increased resistance to toad toxin and a decreased preference for toads as prey. Separate laboratory experiments suggest that these changes are not attributable to learning (we were unable to teach naive snakes to avoid toxic prey) or to acquired resistance (repeated sub-lethal doses did not enhance resistance). These results strongly suggest that black snake behaviour and physiology have evolved in response to the presence of toads, and have done so rapidly. Toads were brought to Australia in 1935, so these evolved responses have occurred in fewer than 23 snake generations.

Phillips, Ben L; Shine, Richard

2006-01-01

68

Toad envenoming in dogs: effects and treatment  

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Full Text Available SciELO Brazil | Language: English Abstract in english Toads (order: Anura; family: Bufonidae; genus: Bufo) are distributed throughout the world, but more species are found in areas of tropical and humid temperate climates. Although toads do not have a venom inoculation system, they are venomous animals because the glands covering the whole surface of t [...] heir bodies secrete a milk-like venom of which composition is not yet completely known. Some of these glands are the bilateral glands located in post-orbital position. These glands, which are somewhat diamond-shaped and can be seen by the naked eye, are known as parotids. Toad envenoming in dogs may cause local and systemic alterations and may cause death by cardiac ventricular fibrillation. The electrocardiographic alterations observed consist of gradual deterioration of the normal standards with progressive appearance of negative ventricular deflections that can result in ventricular fibrillation and death if the envenomed dog is not promptly treated. Traditional therapy consists mainly of administration of atropine and propranolol; the latter used to prevent ventricular fibrillation.

M., SAKATE; P. C. LUCAS DE, OLIVEIRA.

69

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

Science.gov (United States)

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

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

2009-01-01

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Hematological values in hermaphrodite, Bufo bufo (Linnaeus, 1758)  

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Five male, four female, and nineteen hermaphrodite Bufo bufo specimens were examined in terms of six hematological parameters, namely; red blood cell count, hemoglobin concentration, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The erythrocyte count and hematocrit of hermaphrodite specimens were found to be more than those of males and females in the pre-reproductive period. When all parameters were compared between sexes duri...

2009-01-01

71

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  

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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...

2000-01-01

72

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

73

Miniaturized Bioaffinity Assessment Coupled to Mass Spectrometry for Guided Purification of Bioactives from Toad and Cone Snail  

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Full Text Available A nano-flow high-resolution screening platform, featuring a parallel chip-based microfluidic bioassay and mass spectrometry coupled to nano-liquid chromatography, was applied to screen animal venoms for nicotinic acetylcholine receptor like (nAChR affinity by using the acetylcholine binding protein, a mimic of the nAChR. The potential of this microfluidic platform is demonstrated by profiling the Conus textile venom proteome, consisting of over 1,000 peptides. Within one analysis (<90 min, 500 ng venom injected, ligands are detected and identified. To show applicability for non-peptides, small molecular ligands such as steroidal ligands were identified in skin secretions from two toad species (Bufo alvarius and Bufo marinus. Bioactives from the toad samples were subsequently isolated by MS-guided fractionation. The fractions analyzed by NMR and a radioligand binding assay with ?7-nAChR confirmed the identity and bioactivity of several new ligands.

Ferry Heus

2014-02-01

74

Egg Water from the Amphibian Bufo arenarum Modulates the Ability of Homologous Sperm to Undergo the Acrosome Reaction in the Presence of the Vitelline Envelope1  

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Sperm from the toad Bufo arenarum must penetrate the egg jelly before reaching the vitelline envelope (VE), where the acrosome reaction is triggered. When the jelly coat is removed, sperm still bind to the VE, but acrosomal exocytosis is not promoted. Our previous work demonstrated that diffusible substances of the jelly coat, termed “egg water” (EW), triggered capacitation-like changes in B. arenarum sperm, promoting the acquisition of a transient fertilizing capacity. In the present wor...

Krapf, Dari?o; O Brien, Emma D.; Cabada, Marcelo O.; Visconti, Pablo E.; Arranz, Silvia E.

2009-01-01

75

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 "1"4C-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 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

1987-01-01

76

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

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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

77

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

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

Ratnikov, V. Yu

2013-06-01

78

Electrophoretic patterns of proteins in the secretion of Parotoid gland and its extract in Bufo melanostictus (Schneider  

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Full Text Available The present study was carried out to analyze qualitatively the Electrophoretic patterns of proteins in Parotoid gland extract and its secretion in terrestrial toad Bufo melanostictus (Indian toad. The patterns indicated that the gland extraction has higher number of protein bands compared to the gland secretion. The patterns of protein bands observed in the parotoid gland extraction of B. melanostictus using Sodium Dodecyl Sulphate Poly Acryl amide Gel Electrophoresis (SDS-PAGE indicated a distinct pattern of four protein bands and some additional bands, with poor resolution, where as two protein bands in the parotoid gland secretion. The electrophoretogram revealed that both the patterns of parotoid gland extract and its secretion showed homology in protein bands with minor variations.

Raju Neerati

2013-08-01

79

Issues in Species Recovery: An Example Based on the Wyoming Toad  

Science.gov (United States)

This peer reviewed article from Bioscience journal is about species recovery using the Wyoming toad as an example. The identification and recovery of endangered species is difficult because of their rarity, the continuing threats to their survival, and inadequate funding for research and conservation. There have been some success stories, but also a number of failures. Have biologists learned from our failures, or are we repeating the same mistakes? While habitat availability and cost are important limitations to species recovery, other, more easily addressed issues also hamper recovery programs. The Wyoming toad (Bufo baxteri) is an endangered species whose recovery has been stalled by problems that are common to species recovery efforts, especially for animals without significant "charisma." I summarize the research undertaken on the Wyoming toad since its listing, highlight the difficulties in building a scientifically based recovery program, and identify some of the unmet challenges impeding recovery. Although specific to the Wyoming toad, these recommendations are relevant to recovery programs facing similar issues.

VICTORIA J. DREITZ (;)

2006-09-01

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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  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Diversas espécies de rãs terrestres, tartarugas e insetos desenvolveram mecanismos para resistência ao congelamento, como o aumento dos níveis de glicose, proteínas anticongelantes e enzimas antioxidantes. Neste estudo, verificou-se a importância da glicose para a crioresistência de dois anfíbios an [...] uros: a rã Rana catesbeiana e o sapo Bufo paracnemis. Os animais foram expostos a -2ºC para medidas de glicemia, conteúdo de glicogênio muscular e hepático, hematócrito e volume celular das hemácias. As rãs sobreviveram à exposição, enquanto os sapos não. A glicemia aumentou de 40,35 ± 7,25 para 131,87 ± 20,72 mg/dl (P Abstract in english 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

A. A., STEINER; S. O., PETENUSCI; L. G., BRENTEGANI; L. G. S., BRANCO.

 
 
 
 
81

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

Science.gov (United States)

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

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

2009-01-01

82

Haematological changes in Bufo maculatus treated with sublethal concentrations of Cadmium  

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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

83

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

International Nuclear Information System (INIS)

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

2010-12-01

84

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

85

[Helminth fauna of Bufo raddei in Transbaikalia].  

Science.gov (United States)

Helminth fauna of Bufo raddei from Transbaikalia has been studied in 2003-2007. Eleven species of parasites Nematoda were found in this host, namely Rhabdias bufonis (Schrank, 1788), Oswaldocruzia filiformis (Goeze, 1782), Oswaldocruzia yezoensis Morishita, 1926, Contracaecum osculatum (Rudolphi, 1802), Raphidascaris acus, larvae, Aplectana acuminata (Schrank, 1788), Aplectana multipapillosa Ivanitzky, 1940, Cosmocerca commutata (Diesing, 1851), Cosmocerca ornata (Dujardin, 1845), Cosmocercoids pulcher (Wilkie, 1930), and Spiroxis contortus (Rudolphi, 1819). Morhometric characters of the helminthes are given. Parasites belonging to Monogenea, Cestoda, Trematoda, and Acanthocephala were not found in 382 examined specimens of Bufo raddei. PMID:20536007

Shchepina, N A; Baldanova, D R

2010-01-01

86

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.

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

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THE HELMINTH PARASITOFAUNA OF BUFO REGULARIS (REUSS IN AWKA, ANAMBRA STATE, NIGERIA  

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Full Text Available The term "toad" tends to refer to the "True Toads".... which are members of the family Bufonidae, containing more than300 species. One hundred specimens of Bufo regularis (67 males and 33 females were collected between June 2006 andAugust 2006 in Awka metropolis of Anambra State of Nigeria and examined for helminth parasites or for non-protozoan gut andtissue parasites. Seventy one percent (71% (48 males and 23 females of the specimens were infected by five hundred andforty-three (543 parasitic helminthes made up of 475(89% nematodes, 6(2% pentastomids and 62(14% trematodes. Theseseven species collected include Nematoda: Ascaridoid larva (12%, Rhabdias bufonis(30%, Camallanus sp.(10%, Amplicaecumafricanum(31%, Ascaridoid(6%; Trematoda: Messocoelium monodi(14%; Pentastomida: Raillietiella sp.(6%.Amplicaecum africanum was most prevalent in males with 24% than in females 7%. Also Rhabdias bufonis was most prevalent inmales with 19% than in females 11% and the differences were statistically significant. Prevalence also varied with length andweight. Male toads in the length classes of 11.0-11.9cm and 12.0-12.9cm had the highest prevalence of 100% while those in 7.0-7.9cm length class had the least prevalence of 60%. Females in the 10.0-10.9cm length class had the highest prevalence of81.82% while those in 9.0-9.9cm length class had the least prevalence of 50% (P<0.05. Males in 101-120g weight class had thehighest prevalence of 100% while those in the 61-80g weight class had the least prevalence of 63.64%. Females in 141-160gweight class had the highest prevalence of 100%while those in the weight classes of 41-60g, 61-80g and 81-100g had the leastprevalence of 75% and the differences were statistically significant.(P<0.05. All the helminths exhibited site preferences exceptone nematode, Amplicaecum africanum, recovered from rectum, intestine and stomach of both male and female toads.Parasite abundance was variable from one toad size class to another. It appeared that there was a general tendency for theprevalences to increase with increase in size of the host.

NWORAH DC, OLORUNFEMI OJ

2011-12-01

88

Light-dependent binding of G-protein to outer segment membranes of toad photoreceptors [published erratum appears in J Gen Physiol 1987 May;89(5):following 837  

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Light-dependent changes in the binding of G-protein were analyzed in outer segment disk membranes obtained from photoreceptors of the toad (Bufo marinus) retina. Isolated, intact retinas, incubated in oxygenated Ringer's solution at 23 +/- 1 degree C, were subjected to various conditions of illumination and then incubated in darkness for specified periods. The retinas were then chilled (0-4 degrees C) and the receptor outer segments (ROS) were isolated. Binding of the alpha- and beta-subunits...

1986-01-01

89

Estudo sôbre hemoparasitos de Bufo marinus L. da Venezuela: 1. Hemogregarinas - - 2. Uma nova espécie de Toxoplasma  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Faz-se uma revisão das espécies de Haemogregarina, encontradas, até a presente data, em Bufo marinus L. da região Norte, Leste e Sul da Venezuela,descrevendo-se o ciclo agâmico da Haemogregarina darlingi Leger, 1918, o ciclo esquizogônico da Haemogregarina aquai Phisalix, 1930, propondo-se seja deno [...] minada Karyolysus aquai (Phisalix) por realizar o ciclo agâmico nas células endoteliais. Descreve-se a Haemogregarina legeri nov. sp. Estuda-se um Toxoplasma no sangue e vísceras de Bufo marinus L., descrevendo-se a anatomia patológica dos órgãos afetados, discutindo-se o estado atual da sistemática das espécies de Toxoplasma, parasitos de vertebrados poikilotermos, propondo-se o nome de Toxoplasma serpai nov. sp. para êste protozoário. Abstract in spanish Se hace una revisión de las especies de Haemogregarina encontradas hasta el presente en Bufo marinus L. de la región neotrópica, estudiando estos parásitos en sapos del centro, norte, oriente y sur de Venezuela, describiendo el ciclo agamico de la Haemogregarina darlingi Leger 1918, el ciclo esquizo [...] gonico de la Haemogregarina aquai Phisalix 1930, proponiendo denominaria Karyolysus aquai (Phisalix) por realizar su ciclo agámico en las células endoteliales. Se describe la Haemogregarina legeri nov. sp. Se estudia un Toxoplasma en la sangre y visceras de bufo marinus L. describiendo la anatomia patológica de los órganos afectados, discutiendose el estado actual de la sistematica de Toxoplasma parasitos de vertebrados poikilotermos, proponiendo el nombre de Toxoplasma serpai nov. sp. para este protozoario. Abstract in english A revision is made of the species of Haemogregarina found up to now in Bufo marinus L. from the Neotropical Region. Parasites in toads from the north, center, south and east of Venezuela are studied and descriptions are made of the agamic cycle of Haemogregarina darlingi Leger 1918; the schizogonic [...] cycle of Haemogregarina aquai Phisalix 1930, proposing reclassify it as Karyolysus aquai (Phisalix) since its agamic cycle is carried through in endothelial cells, and Haemogregarina legeri nov. sp. A Toxoplasma is studied in the blood and viscera of Bufo marinus L. describing the pathology of affected organs, proposing the name Toxoplasma serpai nov. sp. for it. The actual state of the systematics of Toxoplasma parasites in poikilotherm vertebrates is discussed.

Scorza, José Vicente; Dagert B., Cecilia; Arocha, Luís Iturriza.

90

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

91

Variación estacional en la proporción relativa de los estadios de la oogénesis en Bufo arenarum (Anura: Bufonidae  

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Full Text Available The Anova repeated measure design was used to compare the percentage of oocytes in female toads (Bufo arenarum at stages 1 to 5 and at different physiological ovary periods (or phases: production, before ovulation, after ovulation. Individual comparisons among stages and between phases have been made with the minimum significant difference method at 0.05 probability level. The statistical analysis at percentage of oocytes showed that: a Stages 1 and 2 have few variation. They are the permanent oocytes group. b Stage 3 (late vitelogenesis oocytes are absent previous to the breeding season. Their rate increases in summer and decreases in autumn. The development of oocytes 3 take place afterwards the ovulation. c Stage 4 increases in autumn and disappears in late winter. d Stage 5 sets up as the 18% of the ovulated oocytes. e. Stages 3, 4 and 5 are renewed every year; they are temporary ovarian oocytes.

Echeverría, Dinorah D.

1994-01-01

92

Toad poisoning in three dogs: case reports  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 irrita...

2009-01-01

93

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

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

Inoue Eiji

2014-03-01

94

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

2007-05-01

95

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

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The generic assignment of three fossil forms described as Bufo belogoricus Ratnikov, 1993, Bufo planus Ratnikov, 1993 and Bufo albus Ratnikov, 1993 is discussed. The author justifies why their original generic names should not be changed to Pseudepidalea, as recently proposed, but should be maintained until more convincing evidence is discovered.Se discute la atribución genérica de tres formas fósiles descritas como Bufo belogoricus Ratnikov, 1993...

Ratnikov, V. Yu

2013-01-01

96

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

2013-06-01

97

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.

98

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

99

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

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

Liang, Christina T.; Stohlgren, Thomas J.

2011-06-01

100

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

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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

 
 
 
 
101

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

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

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

2013-12-01

102

Morphology of Bufo ictericus integument (Amphibia, Bufonidae).  

Science.gov (United States)

Bufo ictericus integument was investigated by stereoscopic, low vacuum scanning electron microscopy, transmission electron microscopy and light microscopy. The studies revealed, that the dorsal integument surface is rougher than ventral. Three types of projections are visualized: larger rounded verrucae, smaller conical cornified tubercles, and conical short spines. Prominent verrucae are observed on the dorsal surface, being flatter on the ventral surface. The tubercles are visualized only on the dorsal surface. The verrucae are separated by grooves that may contribute spreading and retention of the glandular secretion upon the integument. The pattern of the epidermal grooves is also important for water distribution, protecting the animal against desiccation. The epidermis is composed of a stratified epithelium with intraepithelial blood vessels, where keratinocytes predominate, but flask cells, and Merkel cells also occur. In the spongious dermis, cutaneous glands are visualized. The compact dermis is a series of alternating layers of bundles of collagenous fibers, and between spongious and compact dermis there are basophilic areas that correspond to Eberth-Katschenko layer. The dorsal and the ventral surfaces of B. ictericus are morphologically distinct. The integument structure is related to the physiology of each surface and represents an adaptation to habitat, reflecting a lifestyle of the animal. PMID:15975802

de Brito-Gitirana, L; Azevedo, R A

2005-01-01

103

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

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

104

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

Science.gov (United States)

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

Donaldson, P J; Leader, J P

1993-11-01

105

Estereoultraestructura del pulmón de anuros bufónidos. Bufo arenarum  

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Full Text Available Scanning electron microscopy was used to determined the inner morphology of the Bufo arenarum lung. The observations let conclude that the lung presents three types of folds which divide the organ into alveolar spaces. The inner surface of the lung, as well as the lateral wall of the folds are lined with respiratory epithelium, except in the apex of the primary folds (ciliated surface with goblet cells and in the secondary folds (ciliated surface.

Hermida, Gladys N.

1994-01-01

106

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...

107

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

Science.gov (United States)

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

108

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

Scientific Electronic Library Online (English)

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

Azevedo, MFC; Foresti, F.; Ramos, PRR; Jim, J.

109

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

110

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

111

Interaction between Pax6 and its novel mutant in Bufo raddei Strauch  

Science.gov (United States)

Purpose Exploration of the relationship between a novel paired box 6 (Pax6) mutant and Pax6 in Bufo raddei Strauch. Methods RT–PCR, yeast 2-hybrid system, and co-immunoprecipitation were used to analyze the Pax6 protein and its mutant during embryonic eye development in Bufo raddei Strauch. Results We have cloned the Pax6 ORF sequence from Bufo raddei Strauch. Here we report the cloning of a novel Pax6 homolog of Bufo raddei Strauch named Pax6 variant. Comparing the 2 genes, the homolog of ORF nucleotide sequence is more than 99% in Bufo raddei Strauch; only the proline-serine-threonine(PST)-rich transaction domain differs. The deduced amino acid sequences of PST region are 53.1% identical. An interaction was found between Pax6 and Pax6 variant via yeast 2-hybrid system; with further study, we found that they interacted in vivo via co-immunopricipitation. Conclusions A Pax6 mutant was first found in Bufo raddei Strauch. Interaction between Pax6 and Pax6 variant may play a critical role during eye development in Bufo raddei Strauch. This suggests that expression of Pax6 variant may play a role and appears to be a necessity in eye development, but that Pax6 itself is still pivotal in eye development.

Ju, Furong; Zhao, Yongqing; Zhao, Yuanlin; Wang, Ying; Wen, Fan; Ye, Lin

2011-01-01

112

Differential effects of malathion and nitrate exposure on American Toad and Wood Frog tadpoles.  

Science.gov (United States)

Organisms living in aquatic ecosystems are increasingly likely to be exposed to multiple pollutants at the same time due to the simultaneous use of several pesticides and fertilizers. We examined the single and interactive effects of environmentally realistic concentrations of nitrate and malathion on two species of tadpoles common in agricultural regions of the United States-the American Toad (Bufo americanus) and the Wood Frog (Rana sylvatica)-using a fully factorial mesocosm experiment that crossed four concentrations of malathion ranging from 0 to 1000 ?g/l and two concentrations of nitrate (0 or 8 mg/l). In both B. americanus and R. sylvatica, malathion delayed metamorphosis compared to controls, even at the lowest concentration of malathion. Malathion did not affect survivorship in either species. B. americanus metamorphs were smaller in malathion treatments, whereas R. sylvatica were larger in malathion treatments. Nitrate did not affect survivorship or metamorph size in either species, but did accelerate time to metamorphosis in R. sylvatica. The interaction between nitrate and malathion had no effects in B. americanus and had no effect on R. sylvatica survivorship or metamorph size. However, in the 250 ?g/l and 500 ?g/l malathion treatments, nitrate reduced the negative effect of malathion on time to metamorphosis in R. sylvatica such that there was little if any delay in metamorphosis compared to the controls in these treatment combinations. This observation suggests that the presence of nitrate might ameliorate the effects of malathion on R. sylvatica. Our results suggest that malathion could have significant effects on anuran populations and communities and that nitrate might potentially mediate such effects in some species. PMID:20556601

Smith, Geoffrey R; Krishnamurthy, S V; Burger, Anthony C; Mills, Leonard B

2011-02-01

113

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

1997-07-01

114

Spadefoot toads break the rules in dry weather  

Science.gov (United States)

Desert-dwelling animals have all kinds of clever tricks for surviving in their dry environments. This includes the spadefoot toad, which is named for the hard, pointy "spade" on its hind feet, which is used for digging.

American Association for the Advancement of Science (AAAS;)

2007-11-08

115

Effect of an acute glucose overload on Islet cell morphology and secretory function in the toad.  

Science.gov (United States)

The aim of this work was to study the effect of induced hyperglycemia on islet cell mass and insulin secretion in normal toads. Immunolabeled beta cell area, replication (bromodeoxyuridine) and apoptosis (propidium iodide) rate, islet neogenesis (cytokeratin), and insulin secretion in vitro were measured in adult male specimens of Bufo arenarum during and after interruption of the injection of either a 50% glucose solution (2 g/100 g) or its vehicle for 4 days. Glucose administration caused hyperglycemia (122.6 +/- 16.7 and 508.3 +/- 115.9 mg/dl vs 23.5 +/- 1.26 and 22.8 +/- 1.8 mg/dl, at days 3 and 5, respectively, P < 0.05) and a significant decrease in the number of islets/mm(2) (day 3: 9.7 +/- 0.9 vs 3.3 +/- 0.4, P < 0.05; day 5: 9.4 +/- 0.8 vs 7.4 +/- 0.6; day 9: 9.6 +/- 0.9 vs 6.2 +/- 0.4, P < 0.05) and in the percentage of immunolabeled beta cell area (day 3: 2.07 +/- 0.2 vs 0.5 +/- 0.1%, P < 0.05; day 5: 1.8 +/- 0.1 vs 0.6 +/- 0.1%; day 9: 1.7 +/- 0.1 vs 0.7 +/- 0.1%, P < 0.05). Glucose-injected animals had a simultaneous significantly higher percentage of BrdU-labeled beta cells (day 3: 0.46 +/- 0.02 vs 0.23 +/- 0.03%; day 5: 0.54 +/- 0.13 vs 0.22 +/- 0.02%; day 9: 0.61 +/- 0.0 vs 0.27 +/- 0.05%, P < 0.05) and cytokeratin-labeled endocrine cells (day 3: 0.21 +/- 0.06 vs 0.01 +/- 0.00%; day 5: 0.17 +/- 0.06 vs 0.01 +/- 0.01%; day 9: 1.25 +/- 0.2 vs 0.01 +/- 0.008%, P < 0.05) and a higher rate of apoptotic beta cells (day 3: 0.14 +/- 0.04 vs 0.05 +/- 0.02%; day 5: 0.4 +/- 0.06 vs 0.05 +/- 0.2, P < 0.05; day 9: 0.47 +/- 0.04 vs 0.06 +/- 0.03, P < 0.05). Comparable amounts of insulin were secreted in vitro by both groups in response to 2 mM glucose, whereas there was a significantly reduced response to 8 mM glucose in treated animals (day 3: 73 +/- 12 vs 165 +/- 20%; day 5: 74 +/- 11 vs 204 +/- 18%, P < 0.05). This decreased response to high glucose reverted to normal after removal of the glucose injection. These results show for the first time that short-term hyperglycemia triggers marked morphological and transient secretory changes in the toad pancreas similar in part to those elicited in the pancreas of several mammals. As with other results previously reported, these results support the usefulness of the toad as an alternative easily handled model to study the growth and secretory function of the endocrine pancreas. PMID:11316418

Francini, F; Del Zotto, H; Gagliardino, J J

2001-05-01

116

MCBCP Arroyo Toad Monitoring Results for 2006 with Multi-Year Trend Analysis. Data Summary.  

Science.gov (United States)

In 2003, the USGS implemented a new monitoring program for the endangered arroyo toad (Anaxyrus californicus) on Marine Corps Base Camp Pendleton (MCBCP). To address problems associated with large variations in adult toad activity, we employed a spatial a...

C. J. Rochester C. S. Brehme G. M. Turschak R. N. Fisher S. L. Schuster

2008-01-01

117

Diet of Physalaemus cf. cicada (Leptodactylidae and Bufo granulosus (Bufonidae in a semideciduous forest Dieta de Physalaemus cf. cicada (Leptodactylidae e Bufo granulosus (Bufonidae em uma floresta semidecídua  

Directory of Open Access Journals (Sweden)

Full Text Available We determined the diet of the two most abundant anuran species which occur in the litter of a semideciduous forest (Lençóis, Bahia, Brazil, Physalaemus cf. cicada and Bufo granulosus in the dry and rainy seasons. Pitfall traps were used to collect anuran and invertebrate fauna, which showed the availability of prey in the environment. Physalaemus cf. cicada was present in both seasons and Bufo granulosus only in the rainy season. Both species fed mainly on Isoptera and Formicidae. However, there is a difference between the rainy and dry seasons concerning the diet of P. cf. cicada. During the rainy season P. cf. cicada consumed less Isoptera and more Formicidae than in the dry season. In the volumetric sense, Orthoptera was the most important alimentary category for P. cf. cicada and B. granulosus. The Jacobs’ electivity index indicated that Physalaemus cf. cicada and Bufo granulosus were specialists in Isoptera.Foi determinada a dieta das duas espécies mais abundantes de anuros que ocorrem na serrapilheira de uma floresta semidecídua (Lençóis, Bahia, Brasil, Physalaemus cf. cicada e Bufo granulosus, nas estações seca e chuvosa. Armadilhas de queda foram usadas para a coleta de anuros e fauna de invertebrados que indicaram a disponibilidade de presas no ambiente. Physalaemus cf. cicada estava presente em ambas as estações e Bufo granulosus, só na estação chuvosa. Ambas as espécies alimentaram-se principalmente de Isoptera e Formicidae. Porém, houve uma diferença entre estações chuvosa e seca relativo à dieta de P. cf. cicada. Durante a estação chuvosa, P. cf. cicada consumiu menos Isoptera e mais Formicidae que na estação seca. Volumetricamente, Orthoptera foi a categoria alimentar mais importante para P. cf. cicada e B. granulosus. O índice de eletividade de Jacobs indicou que Physalaemus cf. cicada e Bufo granulosus são especialistas em Isoptera.

AS. Santana

2007-02-01

118

Behavioral responses of bufo arenarum tadpoles to odonate naiad predation  

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Full Text Available Abstract.—In the presence of predators, anuran tadpoles often exhibit behavioral plasticity, which in turn reduces predationrisk. We evaluated indirect effects of odonate larva predation on activity of Bufo arenarum tadpoles. We reared intact andtail-damaged larvae in three different predator treatments: (1 caged predators fed tadpoles; (2 caged predators that werestarved; and (3 no predators. Both intact and damaged tadpoles were significantly less active when exposed to predator cues.There were no differences in activity between tadpoles with damaged and intact tails, however significant differences wereobserved between fed and starved predator treatments. Our results are consistent with other studies that have shown bufonidtadpoles reduce activity when exposed to predator cues and address a novel contribution of southern-hemisphere bufonid,expanding the knowledge of that family in ecological experiments.

MARIANA PUETA

2006-12-01

119

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in spanish Existe evidencia de que los niveles de metal ambientales afectan la función inmune. En el caso particular del impacto de metales pesados, la información disponible sugiere que el sistema inmune es un blanco para la exposición a bajas dosis de Pb. Entre los vertebrados, se ha mostrado que los anfibio [...] s son capaces de formar anticuerpos contra una variedad de antígenos, que causan diversas respuestas, tales como respuesta anafiláctica y rechazo de injertos. En este estudio, la producción de anticuerpos fue evaluada contra eritrocitos de oveja (EO) en el anuro Bufo arenarum, luego de seis inyecciones semanales de dosis subletales de plomo (50 mg.kg-1, como acetato de Pb). Los anticuerpos naturales (heteroaglutininas naturales) fueron también cuantificados contra EO. Ambas evaluaciones fueron llevadas a cabo empleando un método de ELISA desarrollado a este fin, midiendo la absorbancia (A). Para los anticuerpos anti-EO naturales, tanto en sapos controles (C) como en sapos tratados con Pb (T), hubo una tendencia significativa a incrementar las absorbancias iniciales (C inicial: 0,69±0,39 A; T inicial: 0,54±0,30 A); la relación T/C tampoco mostró cambios. La única diferencia significativa se encontró entre las muestras inicial y final de los sapos tratados con plomo (p Abstract in english There is evidence that environmental metal levels affect the immune function. In the particular case of the impact of heavy metals, information available suggests that the immune system is a target for low-dose Pb exposure. Among vertebrates it was shown that amphibians are capable of forming antibo [...] dies against a variety of antigens, causing several responses such as anaphylactic response and rejecting grafts. In this study, the production of antibodies was assessed against sheep red blood cells (SRBC) in the anuran Bufo arenarum after six weekly injections of sublethal doses of lead (50 mg.kg-1, as lead acetate). Natural antibodies (natural heteroagglutinins) were also quantified against SRBC. Both assessments were carried out employing an ELISA method developed to this end, measuring absorbance (A). For natural anti-SRBC antibodies in both control (C) and Pb treated (T) toads, there was a non significant tendency to increase the initial absorbances (C initial: 0.69±0.39 A; T initial: 0.54±0.30 A), relative to those registered at the end of the experiments (C final: 0.89±0.49 A; T final: 0.76±0.31A); the T/C ratios also did not show changes. The only significant difference was found between initial and final samples from lead-treated toads (p

Carolina E., Rosenberg; Nilda E., Fink; Alfredo, Salibián.

120

Clinical and electrocardiographic evaluation during experimental toad poisoning in dogs  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Accidents involving toad poisoning are frequent and dogs are the most common victims; they become poisoned by biting or ingesting a toad. When released in the organism, the venom is absorbed by both the oral mucosa and the digestive tract, initiating its toxic action. The aim of this work was to eva [...] luate the clinical and electrocardiographic aspects of dogs subjected to experimental toad poisoning, as well as their response to treatment with propranolol. Twenty dogs were divided into two groups, a control group (n = 5) and a poisoned group (n = 15). After general anesthesia, the control group received a placebo, while the poisoned group received a venom aliquot through an orogastric tube. Results were tested through multivariate analysis (p

AC, Camplesi; M, Sakate; NMB, Simão; R, Marucio; FCD, Mota; CF, Moya-Araujo.

 
 
 
 
121

Morfologia da glândula intermaxilar do sapo (Bufo paracnemis Lutz, 1925  

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Full Text Available The intermaxillary gland of Bufo paracnemis Lutz, 1925 is located at the pre-nasal area being divided anteriorly by the ascendent processes of the intermaxillary bone. The secretory tubules converge to form very ramified ducts which drain into a common opening in a fosseta underlying the vomer bone. The cells of the intermaxillary gland were be classified in four distinct types: Light-granule secretory; Dark-granule secretory; ciliated and basal cells. The light-granule secretory cells, are the main type of the secretory tubules, which are also found, in smaller numbers, in the excretory ducts. The dark-granule secretory cells appear in a low number, both in the secretory tubules and in the excretory ducts. Degranulated cells are frequently found in the excretory ducts and represent the degranulated phase of dark-granule secretory cells. The ciliated cells occur only in the excretory ducts. The basal cells occur in small number in the excretory ducts and secretory tubules. In the excretory ducts these cells are regarded as being mioepithelial cells. Although usually described in the literature as mucous, the secretory cells of the intermaxillary gland have serous characteristics. The intermaxillary gland is the first salivary gland to appear in the vertebrate evolution. Its duct system is uniformly lined by ciliated cells and scattered secretory cells. This indicates that in the evolution, of salivary glands, there was a diversification of the duct system, together with progressxve concentration of secretory cells in special áreas of this system.

Marlene Soares Dias Alves

1988-01-01

122

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

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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...

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

2006-01-01

123

Aluminum-zinc antagonism in Bufo arenarum embryos  

Energy Technology Data Exchange (ETDEWEB)

As a result of their aquatic embryonic and larval development, many species of amphibians are potentially affected by adverse environmental conditions. In this study the possibility of reducing the lethal effect of aluminum (ALC13, Mallinckrodt) in Bufo arenarum embryos by means of simultaneous zinc (ZnSO4) treatment is reported. The aluminum hazard was evaluated in a 7 day renewal toxicity testing study conducted with batches of 10 individuals (by quadruplicate) in six concentrations of aluminum plus the control at 20 C. The pH of the experimental solutions were measured. The LC100 expressed as Al(3 +) mg/L at 24 and up till 168 hours of treatment were 0.9 (the pH of the solution was 6.2 while in control Holtfreter solution the pH was 6.8). Therefore, aluminum exert a lethal effect on amphibian embryos in concentrations which reduce only slightly the pH of the maintaining solution. The lethal effect of aluminum could be reduced 100% by means of simultaneous treatment with 2 mg Zn(2 +)/L. The results point out the high sensibility of the amphibian embryos to aluminum (LC100/24hs:0.9mg Al(3 +)/L) and therefore, episodic increases in dissolved aluminum, usually concomitant with surface water pH decreases, could produce very harmful effects during embryonic stages of amphibians. The noteworthy beneficial effect of zinc against the lethal effect of aluminum could be of practical value in reducing the harmful effects exerted by aluminum. The conspicuous Al-Zn antagonism points out the need of biological test systems for recording the integrated effects of substances released to the environment.

Herkovits, J.; Herkovits, F.D.; Perez-Coll [Inst. de Ciencias Ambientales y Salud, Buenos Aires (Argentina). Programa Seguridad Quimica

1995-12-31

124

The envelopes of amphibian oocytes: physiological modifications in Bufo arenarum  

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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

125

Morfologia da glândula intermaxilar do sapo (Bufo paracnemis Lutz, 1925)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] Abstract in english The intermaxillary gland of Bufo paracnemis Lutz, 1925 is located at the pre-nasal area being divided anteriorly by the ascendent processes of the intermaxillary bone. The secretory tubules converge to form very ramified ducts which drain into a common opening in a fosseta underlying the vomer bone. [...] The cells of the intermaxillary gland were be classified in four distinct types: Light-granule secretory; Dark-granule secretory; ciliated and basal cells. The light-granule secretory cells, are the main type of the secretory tubules, which are also found, in smaller numbers, in the excretory ducts. The dark-granule secretory cells appear in a low number, both in the secretory tubules and in the excretory ducts. Degranulated cells are frequently found in the excretory ducts and represent the degranulated phase of dark-granule secretory cells. The ciliated cells occur only in the excretory ducts. The basal cells occur in small number in the excretory ducts and secretory tubules. In the excretory ducts these cells are regarded as being mioepithelial cells. Although usually described in the literature as mucous, the secretory cells of the intermaxillary gland have serous characteristics. The intermaxillary gland is the first salivary gland to appear in the vertebrate evolution. Its duct system is uniformly lined by ciliated cells and scattered secretory cells. This indicates that in the evolution, of salivary glands, there was a diversification of the duct system, together with progressxve concentration of secretory cells in special áreas of this system.

Marlene Soares Dias, Alves.

126

Toad venom poisoning: resemblance to digoxin toxicity and therapeutic implications  

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A healthy man developed gastrointestinal symptoms after ingesting purported aphrodisiac pills. He had severe unrelenting bradycardia, hyperkalaemia, and acidosis. He rapidly developed severe life threatening cardiac arrhythmias and died after a few hours. He was found to have positive serum digoxin concentrations, although he was not taking digoxin. Toad venom poisoning is similar to digitalis toxicity and carries a high mortality. Cardiac glycoside poisoning can occur from ingestion of vario...

2003-01-01

127

Interaction of vasopressin and prostaglandins in the toad urinary bladder.  

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Prostaglandins are important modulators of the action of vasopressin. Others researchers have proposed that vasopressin stimulates prostaglandin synthesis, completing a negative feedback loop and thereby limiting vasopressin's antidiuretic effect. We have re-examined this question, using specific radioimmunoassay and thin-layer radiochromatography to determine prostaglandin synthesis by the toad bladder. Under control conditions, the bladder synthesizes prostaglandin (PG)E2 and thromboxane (T...

Bisordi, J. E.; Schlondorff, D.; Hays, R. M.

1980-01-01

128

Rhabdias esculentarum n. sp. (Nematoda: Rhabdiasidae) from green frogs of the Rana esculenta species complex in Italy: molecular evidence, morphological description and genetic differentiation from its congeners in frogs and toads.  

Science.gov (United States)

A new taxon, Rhabdias esculentarum n. sp., is described based on DNA sequence analysis at multiple loci (i.e. mtDNA cox-1, 12S rRNA, ITS-1 and partial ITS-2 regions of the nuclear rDNA) and morphometric analysis carried out on specimens collected from the green frogs of the Rana esculenta species complex in Italy (i.e. R. lessonae Camerano and R. esculenta Linnaeus, identified genetically by diagnostic allozyme loci). Rhabdias esculentarum n. sp. was differentiated genetically, at both mitochondrial and nuclear levels, from Rh. bufonis (Schrank, 1788) (sensu Hartwich, 1972) and Rh. sphaerocephala Goodey, 1924 recovered from the toad Bufo bufo Linnaeus collected sympatrically with the specimens of Rana lessonae and R. esculenta examined in the present study. Moreover, the new taxon proved to be different from the other species of Rhabdias from anurans, which had previously been sequenced using the same genes and deposited in GeneBank. Phylogenetic analyses (MP and ML) inferred from mitochondrial (mtDNA cox-1 and 12S ribosomal RNA) and nuclear (ITS-1 and ITS-2 of the rDNA regions) sequences datasets were congruent in depicting Rh. esculentarum n. sp. as forming a highly supported clade distinct from the sympatric species Rh. bufonis, as well as from Rh. sphaerocephala, characterised on the basis of the same loci. Morphometric analysis and the differential diagnosis of genetically characterised specimens of the new species have revealed differences in several features in comparison with the type-species, Rh. bufonis. Material of the latter species included voucher specimens from Germany deposited by Hartwich (1972) and other specimens collected from B. bufo in Italy. Among the diagnostic characters, the particular cup-shaped buccal capsule characterising Rh. esculentarum is clearly different from the tear-shaped buccal capsule observed in material of R. bufonis obtained from Berlin Museum and collected in the same geographical area as the green frogs under study. Rh. esculentarum was also found to differ in some measurements and allometric characters from Rh. bufonis (sensu Moravec et al., 1997). The data so far collected appear to indicate a host-preference of Rh. esculentarum for Rana lessonae and R. esculenta, which belong to the R. esculenta hybridogenetic species complex in Italy. PMID:22581250

Cipriani, Paolo; Mattiucci, Simonetta; Paoletti, Michela; Santoro, Mario; Nascetti, Giuseppe

2012-06-01

129

Antibacterial activity of lactose-binding lectins from Bufo arenarum skin  

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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

130

The envelopes of amphibian oocytes: physiological modifications in Bufo arenarum  

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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 ...

Barisone Gustavo A; Albertali Isabel E; Sánchez Mercedes; Cabada Marcelo O

2003-01-01

131

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

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Full Text Available There is evidence that environmental metal levels affect the immune function. In the particular case of the impact of heavy metals, information available suggests that the immune system is a target for low-dose Pb exposure. Among vertebrates it was shown that amphibians are capable of forming antibodies against a variety of antigens, causing several responses such as anaphylactic response and rejecting grafts. In this study, the production of antibodies was assessed against sheep red blood cells (SRBC in the anuran Bufo arenarum after six weekly injections of sublethal doses of lead (50 mg.kg-1, as lead acetate. Natural antibodies (natural heteroagglutinins were also quantified against SRBC. Both assessments were carried out employing an ELISA method developed to this end, measuring absorbance (A. For natural anti-SRBC antibodies in both control (C and Pb treated (T toads, there was a non significant tendency to increase the initial absorbances (C initial: 0.69±0.39 A; T initial: 0.54±0.30 A, relative to those registered at the end of the experiments (C final: 0.89±0.49 A; T final: 0.76±0.31A; the T/C ratios also did not show changes. The only significant difference was found between initial and final samples from lead-treated toads (pExiste evidencia de que los niveles de metal ambientales afectan la función inmune. En el caso particular del impacto de metales pesados, la información disponible sugiere que el sistema inmune es un blanco para la exposición a bajas dosis de Pb. Entre los vertebrados, se ha mostrado que los anfibios son capaces de formar anticuerpos contra una variedad de antígenos, que causan diversas respuestas, tales como respuesta anafiláctica y rechazo de injertos. En este estudio, la producción de anticuerpos fue evaluada contra eritrocitos de oveja (EO en el anuro Bufo arenarum, luego de seis inyecciones semanales de dosis subletales de plomo (50 mg.kg-1, como acetato de Pb. Los anticuerpos naturales (heteroaglutininas naturales fueron también cuantificados contra EO. Ambas evaluaciones fueron llevadas a cabo empleando un método de ELISA desarrollado a este fin, midiendo la absorbancia (A. Para los anticuerpos anti-EO naturales, tanto en sapos controles (C como en sapos tratados con Pb (T, hubo una tendencia significativa a incrementar las absorbancias iniciales (C inicial: 0,69±0,39 A; T inicial: 0,54±0,30 A; la relación T/C tampoco mostró cambios. La única diferencia significativa se encontró entre las muestras inicial y final de los sapos tratados con plomo (p<0,014. Los niveles de anticuerpos anti-EO inmune de sapos inmunizados con EO mostraron un bajo incremento significativo (p<0,05 en los animales tratados con plomo (T final: 0,66±0,36 A, al compararse con sapos control (C final: 0,91±0,50 A al final del experimento. De este modo, se concluye que los cambios debidos a las dosis analizadas de Pb en los niveles de anticuerpos no pueden explicarse sólo sobre la base de un único mecanismo de acción del metal, sino como resultado de una conjunción de efectos sobre diferentes subpoblaciones de células inmunocompetentes. Estas diferentes respuestas sugieren que los factores que afectan los animales expuestos a un estímulo externo son diferentes de aquellos que influyen la respuesta en los animales silvestres.

Carolina E. Rosenberg

2007-07-01

132

Antagonism Between Chlorpyrifos and Flaxedil in Toad and Earthworm Neuromuscular Transmission  

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Full Text Available The cholinesterase inhibition effect of chlorpyrifos, a commercial insecticide, was tested by its antagonism to the acetylcholine inhibition effect of flaxedil in 30 isolated nerve-sartorius muscle preparations of the toad, compared with its antagonism in 30 isolated nerve cord-body wall muscle preparations of the earthworm. Inhibition and facilitation in this antagonism were measured by changes in depolarizing rate of toad endplate potential and in earthworm slow potential and by changes in interstimulus interval for evoking an action potential in toad preparations and a graded spike potential in earthworm preparations. Earthworm depolarizing rate (0.32 V s-1 in its normal Ringer was five times lower than that (1.50 V s-1 of toad under [Flaxedilï]o = 3 x 10-3 g cc-1. Earthworm interstimulus interval (15.6 ms in its normal Ringer was nine times longer than that (1.75 ms of toad under [Flaxedil]o = 3 x 10-3 g cc-1. [Flaxedilï]o between 3 x 10-4 g cc-1 and 5 x 10-4 g cc-1 attenuated 25% of toad depolarizing rate and 23% of earthworm depolarizing rate, 60% of toad interstimulus interval and eliminated the earthworm interstimulus interval almost entirely. Enhancement of toad depolarizing rate and interstimulus interval by chlorpyrifos between 5 x 10-4 g cc-1 and 10-2 g cc-1 after being attenuated by flaxedil was not significant but was significant in the earthworm preparation. Inhibition of earthworm cholinesterase by chlorpyrifos may be related to its lower neuromuscular excitability than that of the toad.

Yong-Chiang Chang

2006-01-01

133

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

Science.gov (United States)

...the following physical and biological features: Space for Individual...controlled open- space areas managed by the State of California...Area 1 Open Space conserved lands...toad and the physical and biological...provisions in other State and...

2011-02-09

134

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

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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

135

Comparison of the susceptibility of amphibian (Bufo arenarum embryos) and fish (Cnesterodon decemmaculatus) to aluminum  

Energy Technology Data Exchange (ETDEWEB)

Although crustaceans, fish and algae are receiving increasing attention as test organisms in short-term tests, it is important to note that other species could be more than order of magnitude more susceptible la xenobiotics and therefore, profitable for toxicity screening for a proper protection of the diversity and complexity of the ecosystems. In this report the sensitivity of Bufo arenarum (embryos) and Cnesterodon decemmaculatus to aluminum (AIC1 3) is evaluated in a renewal toxicity test system at 20 C and informed as LC100, LC50 and NOEC for 24 and up till 96 hours of exposure (acute Toxicity Profile -- TPa -- for aluminum). The tests with fish were conducted maintaining 10 individuals in 1 liter of EPA water (by quadruplicate) in six concentration of Al(3+). The pH of the experimental solutions were measured. The LC100, LC50 and NOEC for fishes expressed in Al(3+) mg/L were: 7.5 (the pH of this solutions was 4.3), 7 and 6 at 24 as well as for 48, 72 and 96 hours of exposure, while for Bufo arenarum embryos the LC100, LC50 and NOEC were 0.9 (pH 6.2), 0.6 and 0.1 for 24 hours and up till 96 hours of exposure. Therefore, Bufo arenarum (embryos) seems to be about one order of magnitude more sensitive than the solution is adjusted from 4.3 to 6.2, no lethal effect on fish was registered. The TPa shows that the most toxic period is within the first 24 hours of exposure while on the other hand in fishes as well as in amphibian embryos the LC50 is closer to the LC100 value that to NOEC and therefore, exposure around LC50 concentrations, in the case of aluminum, represents a risk for the whole population.

Herkovits, J.; Herkovits, F.D.; Perez-Coll, C.S. [Inst. de Ciencias Ambientales y Salud, Buenos Aires (Argentina). Programa de Seguridad Quimica

1995-12-31

136

Mercurium-zinc antagonism in Bufo arenarum embryos and Cnesterodon decemmaculatus  

Energy Technology Data Exchange (ETDEWEB)

The identification of mercurium hazard for Cnesterodon decemmaculatus and Bufo arenarum (embryos) was evaluated in a renewal toxicity test system at 20 C and informed as LC100, LC50 and NOEC for 24 and up till 96 hours of exposure (acute Toxicity Profile -- TPa -- for mercurium). On addition the beneficial effect of zinc against the lethal effect of mercurium is reported. The test with fish were conducted maintaining 10 individuals in 1 L of EPA water (by quadruplicate) in six concentrations of Hg plus controls, while for amphibian, batches of 10 Bufo arenarum embryos at stage 25 (by quadruplicate) were maintained in 40 ml of Holtfreter`s solution in six concentration of Hg + (HgCl) plus controls. The LC100, LC50 and NOEC for fishes expressed in Hg (+) mg/L were: 0.60, 0.25 and 0.10 for 24 hours of exposure. These values increased very slightly at least up till 96 hours of exposure. Therefore, Bufo arenarum seems to be about three times more sensitive than Cnesterodon decemmaculatus to mercurium. By means of simultaneous mercurium-zinc treatment (ZnSO4) the lethal effect of mercurium could be reduced in amphibians up till 100% with 18 mg Zn2+/L, while for the fish the best result obtained was a reduction of about 50% of lethality within the first 96 hours of treatment with 20 mg Zn2+/L. As a whole the results point out the high susceptibility of amphibian embryos to xenobiotics, the beneficial effect of zinc against embryos to xenobiotics, the beneficial effect of zinc against toxicity exerted by Hg and the need of biological test systems for recording the combined effects of substances released to the environment.

Herkovits, J.; Herkovits, F.D.; Fernandez, A. [Inst. de Ciencias Ambientales y Salud, Buenos Aires (Argentina). Programa de Seguridad Quimica

1995-12-31

137

Indolizidine 239Q and Quinolizidine 275I. Major alkaloids in two Argentinian bufonid toads (Melanophryniscus)  

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Alkaloid profiles in skin of poison frogs/toads (Dendrobatidae, Mantellidae, Bufonidae, and Myobatrachidae) are highly dependent on diet and hence on the nature of habitat. Extracts of the two species of toads (Melanophryniscus klappenbachi and M. cupreuscapularis) from similar habitats in the Corrientes/Chaco Provinces of Argentina have similar profiles of alkaloids, which differ considerably from profiles from other Melanophryniscus species from Brazil, Uruguay and Argentina. Structures of ...

Daly, John W.; Garraffo, H. Martin; Spande, Thomas F.; Yeh, Herman J. C.; Peltzer, Paola M.; Cacivio, Pedro; Baldo, J. Diego; Faivovich, Julia?n

2008-01-01

138

Characterization and partial purification of solubilized active opiate receptors from toad brain.  

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Opiate receptors have been solubilized from toad brain membranes in active form by using digitonin. Between 40% and 50% of the stereospecific binding activity present in toad brain membranes is recoverable in the ultracentrifugal supernatant of digitonin extracts. Binding of opiates to the solubilized receptor is enhanced 4- to 5-fold by decreasing digitonin concentration to 0.1% or less prior to binding. The solubilized receptor is similar to the membrane-bound receptor in its affinity for v...

Ruegg, U. T.; Cuenod, S.; Hiller, J. M.; Gioannini, T.; Howells, R. D.; Simon, E. J.

1981-01-01

139

Haematological changes in Bufo maculatus treated with sublethal concentrations of Cadmium  

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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 hemo...

Lawrence Ikechukwu Ezemonye; Alex Ajeh Enuneku

2011-01-01

140

Population traits of the burrowing toad Rhinella fernandezae (Gallardo, 1957) (Anura, Bufonidae) Características populacionais do sapo Rhinella fernandezae (Anura, Bufonidae)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Size distribution, sex ratio and use of burrows of the burrowing toad Rhinella fernandezae were studied in Buenos Aires province, Argentina. Two sites separated by approximately 300 m were studied: one was a road next to a swamp, and the other a garden of a country house located further from the swamp. We identified toad burrows, and individuals were sexed, measured and given an individual mark. Burrows were examined in subsequent months after the first sampling to assess the presence of toad...

Lc, Sanchez; Busch, M.

2008-01-01

 
 
 
 
141

Detection of single photons by toad and mouse rods.  

Science.gov (United States)

Amphibian and mammalian rods can both detect single photons of light even though they differ greatly in physical dimensions, mammalian rods being much smaller in diameter than amphibian rods. To understand the changes in physiology and biochemistry required by such large differences in outer segment geometry, we developed a computational approach, taking into account the spatial organization of the outer segment divided into compartments, together with molecular dynamics simulations of the signaling cascade. We generated simulations of the single-photon response together with intrinsic background fluctuations in toad and mouse rods. Combining this computational approach with electrophysiological data from mouse rods, we determined key biochemical parameters. On average around one phosphodiesterase (PDE) molecule is spontaneously active per mouse compartment, similar to the value for toad, which is unexpected due to the much smaller diameter in mouse. A larger number of spontaneously active PDEs decreases dark noise, thereby improving detection of single photons; it also increases cGMP turnover, which accelerates the decay of the light response. These constraints explain the higher PDE density in mammalian compared with amphibian rods that compensates for the much smaller diameter of mammalian disks. We further find that the rate of cGMP hydrolysis by light-activated PDE is diffusion limited, which is not the case for spontaneously activated PDE. As a consequence, in the small outer segment of a mouse rod only a few activated PDEs are sufficient to generate a signal that overcomes noise, which permits a shorter lifetime of activated rhodopsin and greater temporal resolution. PMID:24214653

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

2013-11-26

142

Contribution to the study of immune hemolysis by toad complement  

Directory of Open Access Journals (Sweden)

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

Marisa Gennari

1982-09-01

143

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

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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

144

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.

145

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Bufo spinulosus presenta una amplia y fragmentada distribución en Chile (18º a 33º S) a lo largo de gradientes altitudinales y latitudinales. La variación genética fue estimada utilizando marcadores RAPD ("Random Amplified Polymorphic DNA") en diez poblaciones del norte y centro de Chile. La informa [...] ción morfométrica y genética fue analizada en función de la procedencia geográfica. La correlación entre diferenciación genética y morfométrica fue analizada utilizando la prueba de Mantel. Se observó un incremento en el tamaño corporal en función de la latitud. Los individuos de El Tatio mostraron el tamaño corporal más pequeño y la mayor divergencia morfométrica. El AMOVA aplicado a los datos genéticos indicó que el 57.85 % de la varianza es explicada por diferencias entre regiones y que el 30.12 % de la varianza se encuentra dentro de las poblaciones. Bajos niveles de diferenciación genética intraregional fueron observados en las poblaciones del norte de Chile, mientras que las poblaciones de Chile central mostraron niveles más altos de diferenciación genética. Las pruebas de Mantel revelaron una correlación significativa y positiva entre la variación genética y la distancia geográfica. Cuando excluimos la población de El Tatio, las pruebas de Mantel mostraron correlaciones positivas y significativas entre las distancias morfológicas, genéticas y geográficas. Se discute si la temperatura del agua podría explicar la divergencia morfológica observada en los individuos de El Tatio Abstract in english Bufo spinulosus has a wide and fragmented range distribution in Chile (18° to 33° S) along altitudinal and latitudinal gradients. Genetic variation was estimated using RAPD (Random Amplified Polymorphic DNA) markers in 10 populations from northern and central Chile. Morphometric and genetic informat [...] ion was analyzed as a function of geographical origin. The correlation between genetic and morphometric differentiation was analyzed by the Mantel test. An increase in body size as a function of latitude was observed. Specimens from El Tatio had the smallest body size and the greatest morphometric divergence. The AMOVA applied to genetic data indicated that 57.85 % of the variance is explained by interregional differences and that 30.12 % of the variance is found within populations. Low levels of within-regions genetic differentiation was observed in northern populations while higher levels of genetic differentiation was found in populations from central Chile. Mantel tests revealed a significant, positive correlation between genetic variation and geographic distance. When we excluded El Tatio population, Mantel test analyses showed significant correlations between morphological distance and genetic and geographic distances. We discuss whether water temperature could explain the morphological divergence observed in individuals from El Tatio

Marco A., Méndez; Eduardo R., Soto; Claudio, Correa; Alberto, Veloso; Eliseo, Vergara; Michel, Sallaberry; Patricia, Iturra.

146

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

Directory of Open Access Journals (Sweden)

Full Text Available Bufo spinulosus has a wide and fragmented range distribution in Chile (18° to 33° S along altitudinal and latitudinal gradients. Genetic variation was estimated using RAPD (Random Amplified Polymorphic DNA markers in 10 populations from northern and central Chile. Morphometric and genetic information was analyzed as a function of geographical origin. The correlation between genetic and morphometric differentiation was analyzed by the Mantel test. An increase in body size as a function of latitude was observed. Specimens from El Tatio had the smallest body size and the greatest morphometric divergence. The AMOVA applied to genetic data indicated that 57.85 % of the variance is explained by interregional differences and that 30.12 % of the variance is found within populations. Low levels of within-regions genetic differentiation was observed in northern populations while higher levels of genetic differentiation was found in populations from central Chile. Mantel tests revealed a significant, positive correlation between genetic variation and geographic distance. When we excluded El Tatio population, Mantel test analyses showed significant correlations between morphological distance and genetic and geographic distances. We discuss whether water temperature could explain the morphological divergence observed in individuals from El TatioBufo spinulosus presenta una amplia y fragmentada distribución en Chile (18º a 33º S a lo largo de gradientes altitudinales y latitudinales. La variación genética fue estimada utilizando marcadores RAPD ("Random Amplified Polymorphic DNA" en diez poblaciones del norte y centro de Chile. La información morfométrica y genética fue analizada en función de la procedencia geográfica. La correlación entre diferenciación genética y morfométrica fue analizada utilizando la prueba de Mantel. Se observó un incremento en el tamaño corporal en función de la latitud. Los individuos de El Tatio mostraron el tamaño corporal más pequeño y la mayor divergencia morfométrica. El AMOVA aplicado a los datos genéticos indicó que el 57.85 % de la varianza es explicada por diferencias entre regiones y que el 30.12 % de la varianza se encuentra dentro de las poblaciones. Bajos niveles de diferenciación genética intraregional fueron observados en las poblaciones del norte de Chile, mientras que las poblaciones de Chile central mostraron niveles más altos de diferenciación genética. Las pruebas de Mantel revelaron una correlación significativa y positiva entre la variación genética y la distancia geográfica. Cuando excluimos la población de El Tatio, las pruebas de Mantel mostraron correlaciones positivas y significativas entre las distancias morfológicas, genéticas y geográficas. Se discute si la temperatura del agua podría explicar la divergencia morfológica observada en los individuos de El Tatio

Marco A. Méndez

2004-09-01

147

Contribution to the study of immune hemolysis by toad complement  

Scientific Electronic Library Online (English)

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

Gennari, Marisa; Reis, Moema H.; Ferreira, Vera C. A.; Siqueira, Maria; Bier, Otto G..

148

Effects of detergents on sodium transport in toad urinary bladder.  

Science.gov (United States)

The effects of ionic, nonionic and zwitterionic detergents (zwittergents) on apical sodium permeability of toad urinary bladder were investigated. Applied to the mucosal side at concentrations less than 1/100 of their respective critical micellar concentration (CMC), sodium lauryl sulfate, Triton X-100 and a series of sulfobetaine zwittergents reversibly increased amiloride-sensitive sodium current. These detergents decreased the current at concentrations higher than 1/100 of the CMC and caused large, irreversible increases of tissue electrical conductance at a concentration close to the CMC. Nonionic detergent Tween 80, however, stimulated the current at concentrations from 1/100 to 10,000 of its CMC. The maximum stimulation of current by each zwittergent occurred at 1/100 of its CMC, and the larger the CMC, the greater the stimulation attainable. Analysis of the dependence of current on mucosal sodium concentration in the presence of stimulating doses of a zwittergent and Tween 80 showed that the increase in current was not the result of increased apical maximum sodium permeability, but the consequence of removal of sodium self-inhibition. The amiloride dose-response curve in the presence of stimulating dose of zwittergent was shown to shift to the left and yield a smaller apparent inhibition constant as predicted on the basis of such a removal and an unaltered intrinsic amiloride blocking kinetic. PMID:3090236

Li, J H; Zuzack, J S; Kau, S T

1986-08-01

149

Anticipatory motor patterns limit muscle stretch during landing in toads  

Science.gov (United States)

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

Azizi, Emanuel; Abbott, Emily M.

2013-01-01

150

Stage dependent acute toxicity of exposure of Bufo maculatus and Ptychadena bibroni tadpoles to cadmium (Cd2)  

International Nuclear Information System (INIS)

Tadpoles of Bufo maculatus and Ptychadena bibroni were exposed to five concentrations of Cadmium (Cd2+) (0.1, 0.15, 0.2, 0.25 and 0.5 ?g/L) at four life stages (7, 14, 21 and 28 days) after hatching. Two replicate tanks with 20 tadpoles per replicate were used for the study. Percentage mortality increased with increase in concentration of Cd2+ and exposure time, but decreased as maturation stage increased. Derived 96 h lethal median count (LC50) values increased with increase in maturation and ranged between 0.103 - 0.148 ?lg/L for Bufo maculatus and 0.126 - 0.159 ?lg/L for Ptychadena bibroni. Acute toxicity of Cd2+ was observed to be species specific. Tadpoles of Bufo maculatus were highly sensitive to Cd2+, while tadpoles of Ptychadena bibroni were observed to be better sentinels of Cd2+ due to the higher tolerance level exhibited. The four-week old larvae proved to be a better experimental material for ecotoxicological studies. Since the anuran larvae were sensitive to chemical stressors containing Cd, discharging effluents containing Cd2+ into aquatic ecosystem during amphibian breeding must be avoided. (au)

2006-01-01

151

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

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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 da...

Abdel-latif, H.; Sadek, I. A.

1999-01-01

152

Time-dependent aldosterone metabolism in toad urinary bladder  

International Nuclear Information System (INIS)

Aldosterone (Aldo) metabolism was examined in the toad bladder. Bladders were incubated with [3H]aldosterone (10(-7) M) for 5 h, 1 h, or 10 min. Tissues were analyzed for metabolites using high-pressure liquid chromatography (HPLC). In separate experiments, Na+ transport was assessed by the short-circuit current (SCC) technique. Following a 5-h tissue incubation, about 25% of the [3H]-aldosterone was converted into metabolites including a polar monosulfate metabolite, 20 beta-dihydroaldo (20 beta-DHAldo), small quantities of 5 beta-reduced products, and a variety of 5 alpha-reduced Aldo products including 5 alpha-DHAldo, 3 alpha,5 alpha-tetrahydroaldo (3 alpha,5 alpha-THAldo), and 3 beta,5 alpha-THAldo. Tissues metabolized approximately 10% of the labeled hormone into the same compounds by 1 h. Measurable quantities of these metabolites were also synthesized by bladders exposed to Aldo for only 10 min and then incubated in buffer for an additional 50 min without Aldo. Bladders pretreated with the spironolactone, K+-canrenoate (3.5 X 10(-4) M), and stimulated with Aldo (10(-7) M) generated a peak SCC 44 +/- 6% of that observed in matched pairs stimulated with Aldo (P less than 0.001; n = 6). K+-canrenoate also markedly diminished [3H]aldosterone metabolism at both 5 and 1 h. Thus, metabolic transformation of Aldo begins prior to hormone-induced increases in Na+ transport. Both the generation of certain metabolites (e.g., 5 alpha-reductase pathway products) and the increase in Na+ transport can be selectively inhibited by K+-canrenoate

1988-01-01

153

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

GC-MS analysis of single-skins of ten Melanophryniscus rubriventris toads (five collections of two toads each) captured during their breeding season in NW Argentina has revealed a total of 127 alkaloids of which 56 had not been previously detected in any frog or toad. Included among these new alkaloids are 23 new diastereomers of previously reported alkaloids. What is particularly distinguishing about the alkaloid profiles of these ten collections is the occurrence of many of the alkaloids, w...

2012-01-01

154

Pathways for chloride and sodium transport across toad skin  

DEFF Research Database (Denmark)

The voltage dependecies of Na and Cl fluxes were investigated in the isolated toad skin. With Cl-Ringer's on both sides Cl outflux varied very little with clamping voltage. The same was true for the influx of Cl at depolarizing voltages (psii -psio lessthan0 mV), wheras hyperpolarization led to a marked increase in this flux. A net chloride influx under short circuit conditions indicated active transport of chloride. The outflux of Cl was a saturable function of outside Cl concentration. The outflux of urea was hardly affected by raising outside Cl concentration, and the effect of varying outside nitrate concentration on Cl outflux was likewise small. Both influx and outflux could be inhibited partially bt acetazolamide. The outflux of Na varied with the clamping voltage as would be expected for an ion transported by electrodiffusion, and it was shown that amiloride had no effect on Na outflux, so it was concluded that the Na outflux route is particular. In the absence of Cl in the outside solution a small outflux of Cl persists. Also this flux varied with the clamping voltage according to laws for electrodiffusion. The variation of the ratio of sodium outflux to chloride outflux with clamping voltage indicated free passive diffusion of both these ions under the conditions mentioned. A comparison of the outfluxes of Na and Cl in skins bathed with gluconate Ringer's outside showed that the outflux route of these two ions was cation selective (PNa/PCl=1.88). When the paracellular leak pathway of the skins was opened by exposing the outside to hyperosmolar urea solutions, the ratio of the transport numbers was found to be TNa/TCl=1.71. The roles of the two ions in determining the steady state current-voltage relationships were compared. At hyperpolarizing voltages most or all of the clamping current was carried by an inward Cl flux. By depolarization sodium influx plays an increasing role with increasing depolarization. Under short circuit conditions active chloride transport was found to contribute to the short circuit current.

Bruus, K; Kristensen, P

1976-01-01

155

On facilitation of transmitter release at the toad neuromuscular junction.  

Science.gov (United States)

1. The time dependence of the increase in amplitude (facilitation) of a second end-plate potential (e.p.p.) elicited within 10-100 msec of a preceding e.p.p. was examined at neuromuscular junctions in sartorius muscles of toads. Facilitation was defined by two characteristics, initial facilitation and the time constant of its exponential decay.2. The time constant of decay of facilitation was longer at lower temperatures and the Q(10) was 4.3 in the range 10-25 degrees C. There was no significant effect of temperature on initial facilitation.3. Ouabain (10(-4)-10(-3)M), lithium substitution for sodium, sodium azide (5 mM) and N-ethylmaleimide (NEM, 0.1 mM) initially had no effect on initial facilitation or the decay of facilitation. After some time, they all caused a longer time constant of decay of facilitation and a depression of initial facilitation.4. It was concluded that the decay of facilitation is not directly dependent on active transport of sodium ions, calcium efflux, ATP-dependent movements of calcium or mitochondrial uptake of calcium following an action potential.5. Ouabain, lithium, sodium azide, and NEM all caused an increase in transmitter release. This effect, and the late effects on facilitation, were thought to be due to an increase in intracellular calcium concentration in nerve terminals.6. No relationship was found between the quantal content of e.p.p.s (range, 0.8-100) and initial facilitation, or the time constant of decay of facilitation.7. Substitution of strontium for calcium ions caused a marked prolongation of the time constant of decay of facilitation, and a depression of initial facilitation.8. The results were consistent with the hypothesis that the time constant of decay of facilitation is related to the rate of disappearance of an ;active' complex of calcium (CaA) which, of itself, is not sufficient for transmitter release. It is suggested that an action potential produces CaA which decays with the time constant of facilitation and CaS, a short-life complex of calcium which decays with the time constant of the phasic release of transmitter. The release of transmitter is proportional to some function of [CaA] and [CaS]. PMID:4152979

Balnave, R J; Gage, P W

1974-06-01

156

Ion transport by mitochondria-rich cells in toad skin  

DEFF Research Database (Denmark)

The optical sectioning video imaging technique was used for measurements of the volume of mitochondria-rich (m.r.) cells of the isolated epithelium of toad skin. Under short-circuit conditions, cell volume decreased by about 14% in response to bilateral exposure to Cl-free (gluconate substitution) solutions, apical exposure to a sodium-free solution, or to amiloride. Serosal exposure to ouabain resulted in a large increase in volume, which could be prevented either by the simultaneous application of amiloride in the apical solution or by the exposure of the epithelium to bilateral Cl-free solutions. Unilateral exposure to a Cl-free solution did not prevent ouabain-induced cell swelling. It is concluded that m.r. cells have an amiloride-blockable Na conductance in the apical membrane, a ouabain-sensitive Na pump in the basolateral membrane, and a passive Cl permeability in both membranes. From the initial rate of ouabain-induced cell volume increase the active Na current carried by a single m.r. cell was estimated to be 9.9 +/- 1.3 pA. Voltage clamping of the preparation in the physiological range of potentials (0 to -100 mV, serosa grounded) resulted in a cell volume increase with a time course similar to that of the stimulation of the voltage-dependent Cl conductance. Volume increase and conductance activation were prevented by exposure of the tissue to a Cl-free apical solution. The steady-state volume of the m.r. cells increased with the clamping voltage, and at -100 mV the volume was about 1.15 times that under short-circuit conditions. The rate of volume increase during current passage was significantly decreased by lowering the serosal K concentration (Ki) to 0.5 mM, but was independent of whether Ki was 2.4, 5, or 10 mM. This indicates that the K conductance of the serosal membrane becomes rate limiting for the uptake of KCl when Ki is significantly lower than its physiological value. It is concluded that the voltage-activated Cl currents flow through the m.r. cells and that swelling is caused by an uptakeof Cl ions from the apical bath and K ions from the serosal bath. Bilateral exposure of the tissue to hypo- or hypertonic bathing solutions changed cell volume without detectable changes in the Cl conductance. The volume response to external osmotic perturbations followed that of an osmometer with an osmotically inactive volume of 21%.(ABSTRACT TRUNCATED AT 400 WORDS)

Larsen, Erik Hviid; Ussing, H H

1987-01-01

157

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

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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

158

Calcineurin Regulates Progressive Motility Activation of Rhinella (Bufo) arenarum Sperm Through Dephosphorylation of PKC Substrates.  

Science.gov (United States)

Animals with external fertilization, as amphibians, store their sperm in a quiescent state in the testis. When spermatozoa are released into natural fertilization media, the hypotonic shock triggers activation of sperm motility. Rhinella (Bufo) arenarum sperm are immotile in artificial seminal plasma (ASP, resembling testicular plasma tonicity) but acquire in situ flagellar beating upon dilution. However, if components from the egg shelly coat are added to this medium, motility shifts to a progressive pattern. Recently, we have shown that the signal transduction pathway required for in situ motility activation involves a rise in intracellular cAMP through a transmembrane adenylyl cyclase and activation of PKA, mostly in the midpiece and in the sperm head. In this report, we demonstrate that activation of calcineurin (aka PP2B and PPP3) is required for the shift from in situ to progressive sperm motility. The effect of calcineurin is manifested by dephosphorylation of PKC substrates, and can be promoted by intracellular calcium rise by Ca(2+) ionophore. Both phosphorylated PKC substrates and calcineurin localized to the flagella, indicating a clear differentiation between compartmentalization of PKA and calcineurin pathways. Moreover, no crosstalk is observed between these signaling events, even though both pathways are required for progressive motility acquisition as discussed. J. Cell. Physiol. 229: 1378-1386, 2014. © 2014 Wiley Periodicals, Inc. PMID:24648036

Krapf, Dario; O'Brien, Emma; Maidagán, Paula M; Morales, Enrique S; Visconti, Pablo E; Arranz, Silvia E

2014-10-01

159

Effect Of The Apical Ectodermal Ridge On Mitotic Index In Hind Limb Bud Mesenchyme In Bufo Regularis  

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The apical ectodermal ridge (AER) was formed at stage 51 of Bufo regularis, it persisted at stage 52 (limb bud acquiring paddle-shaped outline), then it disappeared by stage 53 (first indication of fourth and fifth toes). Mitotic index (MI) in the AER (stage 51) was higher (40%) than that of the apical ectoderm at stage 50, then it decreased (15%) by stage 52. By apical ectoderm removal at stage 50, the wound epithelium formed an AER by stage 51. The operated bud (80% of cases) showed a decre...

Abdel Karim, Ahmed E.

1991-01-01

160

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

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

1990-01-01

 
 
 
 
161

Chytridiomycosis related mortality in a midwife toad (Alytes obstetricans) in Belgium  

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Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis, contributes to amphibian declines worldwide. Recently, the fungus has shown to be widely distributed in Belgium and the Netherlands, although no clinical cases of the disease have been diagnosed yet. This case report describes the first case of mortality due to chytridiomycosis in Belgium in a wild population of midwife toads (Alytes obstetricans). The presence of clinical chytridiomycosis, combined with the relatively hig...

Pasmans, Frank; Muijsers, Mariska; Maes, Sofie; Rooij, Pascale; Brutyn, Melanie; Ducatelle, Richard; Haesebrouck, Freddy; Martel, An

2010-01-01

162

Participation of inositol trisphosphate and ryanodine receptors in Bufo arenarum oocyte activation.  

Science.gov (United States)

Calcium is considered the most important second messenger at fertilization. Transient release from intracellular stores is modulated through both agonist-gated channels, IP?Rs and RyRs, which can be found individually or together depending on the oocyte species. Using the four commonly used compounds (thimerosal, caffeine, heparin and ruthenium red), we investigated the existence and interdependence of both IP?Rs and RyRs in mature Bufo arenarum oocytes. We found that caffeine, a well known specific RyRs agonist, was able to trigger oocyte activation in a dose-dependent manner. Microinjection of 10 mM caffeine showed 100% of oocytes exhibiting characteristic morphological criteria of egg activation. Ruthenium red, the specific RyR blocker, was able to inhibit oocyte activation induced either by sperm or caffeine. Our present findings provide the first reported evidence of the existence of RyR in frogs. We further explored the relationship between IP?Rs and RyRs in B. arenarum oocytes by exposing them to the agonists of one class after injecting a blocker of the other class of receptor. We found that thimerosal overcame the inhibitory effect of RyR on oocyte activation, indicating that IP?Rs function as independent receptors. In contrast, previous injection of heparin delayed caffeine-induced calcium release, revealing a relative dependence of RyRs on functional IP?Rs, probably through a CICR mechanism. Both receptors play a role in Ca²+ release mechanisms although their relative contribution to the activation process is unclear. PMID:20880424

Ajmat, M T; Bonilla, F; Zelarayán, L; Bühler, M I

2011-05-01

163

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

164

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

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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

165

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

166

Behaviour of the vitelline envelope in Bufo arenarum oocytes matured in vitro in blockade to polyspermy.  

Science.gov (United States)

During activation of amphibian eggs, cortical granule exocytosis causes elaborate ultrastructural changes in the vitelline envelope. These changes involve modifications in the structure of the vitelline envelope and formation of a fertilization envelope (FE) that can no longer be penetrated by sperm. In Bufo arenarum, as the egg traverses the oviduct, the vitelline envelope is altered by a trypsin-like protease secreted by the oviduct, which induces an increased susceptibility of the vitelline envelope to sperm lysins. Full-grown oocytes of B. arenarum, matured in vitro by progesterone, are polyspermic, although cortical granule exocytosis seems to occur within a normal chronological sequence. These oocytes can be fertilized with or without trypsin treatment, suggesting that the vitelline envelope is totally sperm-permeable. Vitelline envelopes without trypsin treatment cannot retain either gp90 or gp96. This suggests that these glycoproteins are involved in the block to polyspermy and that trypsin treatment of matured in vitro oocytes before insemination is necessary to enable vitelline envelopes to block polyspermy. The loss of the binding capacity in vitelline envelopes isolated from B. arenarum oocytes matured in vitro with trypsin treatment and activated by electric shock suggests that previous trypsin treatment is a necessary step for sperm block to occur. When in vitro matured oocytes were incubated with the product of cortical granules obtained from in vitro matured oocytes (vCGP), vitelline envelopes with trypsin treatment were able to block sperm entry. These oocytes exhibited the characteristic signs of activation. These results support the idea that B. arenarum oocytes can be activated by external stimuli and suggest the presence of unknown oocyte surface receptors linked to the activation machinery in response to fertilization. Electrophoretic profiles obtained by SDS-PAGE of solubilized vitelline envelopes from oocytes matured in vitro revealed the conversion of gp40 (in vitro matured oocytes, without trypsin treatment) to gp38 (ascribable to trypsin activity or cortical granule product activity, CGP) and the conversion of gp70 to gp68 (ascribable to trypsin activity plus CGP activity). Taking into account that only the vitelline envelopes of in vitro matured oocytes with trypsin treatment and activated can block sperm entry, we may suggest that the conversion of gp70 to gp68 is related to the changes associated with sperm binding. PMID:16719945

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

2006-05-01

167

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

Science.gov (United States)

Habitat preservation and management may play an important role in the conservation of the Puerto Rican crested toad, Peltophryne lemur, due to this species' small geographic range and declining native wild population. Bioavailable water concentrations of Polycyclic Aromatic Hydrocarbon (PAH) contaminants within breeding pools at 3 sites were established using Passive Sampling Devices (PSDs) and gas chromatography-mass spectrometry (GC/MS). A more diverse population of PAH analytes were found in higher concentrations at the breeding site that allowed direct vehicular access, but calculated risk quotients indicated low risk to toad reproduction associated with the current PAH analyte levels.

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

2012-01-01

168

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

169

Thromboxane and Stable Prostaglandin Endoperoxide Analogs Stimulate Water Permeability in the Toad Urinary Bladder  

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The effects of thromboxane B2 and the stable prostaglandin endoperoxide analogs (15Z)-hydroxy - 9? - 11? - (epoxymethano)prosta - 5Z,13E - dienoic acid (U44069) and (15Z)-hydroxy -11?,9?-(epoxymethano) prosta-5Z,13E-dienoic acid (U46619) were tested on water flow across the toad urinary bladder. In the presence of indomethacin or meclofenamic acid, inhibitors of prostaglandin and thromboxane A2 synthesis, thromboxane B2 stimulated water flow in a dose-dependent manner. U44069 (1 ?M) stim...

Burch, Ronald M.; Halushka, Perry V.

1980-01-01

170

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

Science.gov (United States)

We study the variation in thermal parameters in two contrasting populations Yungas Redbelly Toads (Melanophryniscus rubriventris) with different discrete color phenotypes comparing field body temperatures, critical thermal maximum and heating rates. We found significant differences in field body temperatures of the different morphs. Temperatures were higher in toads with a high extent of dorsal melanization. No variation was registered in operative temperatures between the study locations at the moment of capture and processing. Critical thermal maximum of toads was positively related with the extent of dorsal melanization. Furthermore, we founded significant differences in heating rates between morphs, where individuals with a high extent of dorsal melanization showed greater heating rates than toads with lower dorsal melanization. The color pattern-thermal parameter relationship observed may influence the activity patterns and body size of individuals. Body temperature is a modulator of physiological and behavioral functions in amphibians, influencing daily and seasonal activity, locomotor performance, digestion rate and growth rate. It is possible that some growth constraints may arise due to the relationship of color pattern-metabolism allowing different morphs to attain similar sizes at different locations instead of body-size clines. PMID:24679965

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

2014-04-01

171

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

172

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

173

The electrical characteristics of active sodium transport in the toad bladder.  

Science.gov (United States)

The mechanism responsible for active sodium transport in the urinary bladder of the toad appears to be located at the serosal boundary of the epithelial cell layer of the bladder. Studies of the potential step observed at the serosal boundary in the open-circuited state were undertaken in an attempt to define the factors responsible for its production. Glass micropipettes were used to measure the serosal potential step in bladders exposed on the serosal side to solutions of high potassium or of high potassium and low chloride concentration. Observed potentials exceed the maximum values which would have been expected if the serosal potential step were a potassium or chloride diffusion potential. Measurements of net cation flux exclude the possibility of a diffusion potential at this border due to the passive movement of any anionic species. The observed independence of transbladder potential and short-circuit current from the pH of the serosal medium over a wide range of pH makes it unlikely that the observed serosal potential step is a hydrogen ion diffusion potential. We conclude that the active sodium transport mechanism in toad bladder is "electrogenic." PMID:13959378

FRAZIER, H S; LEAF, A

1963-01-01

174

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

1977-01-01

175

Electrical activity of the toad telencephalon during tonic immobility (animal hypnosis).  

Science.gov (United States)

During tonic immobility obtained in toads by restraining maneuvers there was an increased incidence of waves in the 8-12 c/s range grouped in spindles, in addition to an overall power increase detected by frequency analysis. There was also abolition of phasic movements, increased firing of anti-gravity muscles, and myosis. The electrographic recordings were characteristic of a state of behavioral alert in this species, supporting the hypothesis that a certain level of information processing may occur during tonic immobility, permitting the animal to detect the moment most appropriate for flight. These changes also occurred in animals with sectioned olfactory nerves, showing that they did not depend solely on ventilatory modifications. PMID:3179570

Hoffmann, A; Menescal-de-Oliveira, L

1988-01-01

176

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 lines to three. The design promises both higher processing speed and accuracy. The design can be evolution for more complex optical circuits of enhanced functionality in which the T-gate is the basic building block. The principles and possibilities of design of alloptical quaternary division circuits are proposed and described through numerical simulation.

Alaa A. Al-Saffar

2014-03-01

177

Evolution of Rapid Development in Spadefoot Toads Is Unrelated to Arid Environments  

Science.gov (United States)

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

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

2014-01-01

178

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.

2010-07-30

179

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)  

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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 metamorphosis 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 sug...

Mf, Izaguirre; Mn, Garci?a-sancho; La, Miranda; Tomas, J.; Vh, Casco

2008-01-01

180

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

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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

 
 
 
 
181

Male-Biased Sexual Size Dimorphism, Resource Defense Polygyny, and Multiple Paternity in the Emei Moustache Toad (Leptobrachium boringii)  

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We tested the hypotheses that the Emei moustache toad (Leptobrachium boringii) exhibits resource defense polygyny and that combat led to the evolution of male-biased sexual size dimorphism. Between February and March of 2011 and 2012, 26 female and 55 male L. boringii from Mount Emei UNESCO World Heritage Site, Sichuan, China, were observed throughout the breeding season. Prior to the breeding season, males grow 10–16 keratinized maxillary nuptial spines, which fall off once the season has ...

Hudson, Cameron M.; Fu, Jinzhong

2013-01-01

182

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

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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

183

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

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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

184

Effect of temperature on nonelectrolyte permeation across the toad urinary bladder.  

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The permeability of the toad urinary bladder to 22 nonelectrolytes was obtained from measurements of radioactive tracer fluxes. The permeability coefficients (P's), after suitable corrections for unstirred layers, were proportional to the olive oil/water partition coefficients for the majority of the molecules (Palpha Koill.3). In the absence of chain branching, inductive effects, and intramolecular hydrogen bonding effects, a hydroxyl group reduced P an average 500-fold and a methylene group increased P an average four fold. Branched chain solutes were less permeable than their straight chain isomers, and small solutes, polar and nonpolar, exhibited higher rates of permeation than expected from the relationship between P and Koil. (Over the molecular size range 18-175 cc/mole Palpha(Molecular Volume)-2.7.) The high rates of permeation of small molecules are consistent with diffusion through a highly organized lipid structure. Large polar solutes, e.g., sucrose, appear to pass across the epithelium via an extracellular shunt pathway. The apparent activation energies (Ealpha) for the permeation of 16 select molecules were obtained from permeability measurements over the temperature range 2-32 degrees C. Linear Arrhenius plots (i.e., log P/T-1) were obtained for all molecules after unstirred layer corrections. In the absence of these corrections "phase transitions" were seen for molecules with very high P's (P greater than 300 X 10(-7) cm/sec), but these are simply due to diffusion limited permeation. Ealpha increased by 2.5-3.6 kcals/mole with the introduction of each additional methylene group into a molecule, and decreased by up to 9 kcals/mole for the addition of a hydroxyl group. Qualitatively similar results were obtained in preliminary studies of olive oil/water partition coefficients. Arrhenius plots of the toad bladder conductance over the temperature range 2-32 degrees C yield apparent activation energies of 4-5 kcals/mole which is identical to that found previously for "leaky" epithelia. PMID:825648

Bindslev, N; Wright, E M

1976-11-22

185

Protein synthesis inhibitors attenuate water flow in vasopressin-stimulated toad urinary bladder  

International Nuclear Information System (INIS)

Vasopressin stimulates the introduction of aggregated particles, which may represent pathways for water flow, into the luminal membrane of toad urinary bladder. It is not known whether water transport pathways are degraded on removal from membrane or whether they are recycled. The authors examined the effect of the protein synthesis inhibitors cycloheximide and puromycin using repeated 30-min cycles of vasopressin followed by washout of vasopressin, all in the presence of an osmotic gradient, a protocol that maximizes aggregate turnover. High dose cycloheximide inhibited flow immediately. Low dose cycloheximide did not affect initial flow. In the absence of vasopressin, inhibition did not develop. Despite the inhibition of flow in vasopressin-treated tissues, the cAMP-dependent protein kinase ratio was elevated in cycloheximide-treated tissues, suggesting modulation at a distal site in the stimulatory cascade. [14C]urea permeability was not inhibited by cycloheximide. Puromycin also inhibited water flow by the fourth challenge with vasopressin. The data suggest that protein synthesis inhibitors attenuate flow at a site that is distal to cAMP-dependent protein kinase. However, the reversal of inhibition in MIX-treated tissues suggests that the water pathway can be fully manifested given suitable stimulation. They conclude that either large stores of the transport system are available or that the transport system is extensively recycled on retrieval from the membrane

1988-01-01

186

Epoxygenase metabolites of arachidonic acid inhibit vasopressin response in toad bladder  

International Nuclear Information System (INIS)

In addition to cyclooxygenase and lipoxygenase pathways, the kidney can also metabolize arachidonic acid by a NADPH-dependent cytochrome P-450 enzyme to epoxyeicosatrienoic acids (EETs); furthermore, 5,6-EET has been shown to alter electrolyte transport across isolated renal tubules. The authors examined the effects of three [14C-labeled]-EETs (5,6-, 11,12-, and 14,15-EET) on osmotic water flow across toad urinary bladder. All three EETs reversibly inhibited vasopressin-stimulated osmotic water flow with 5,6- and 11,12-EET being the most potent. The effects appeared to be independent of prostaglandins EETs inhibited the water flow response to forskolin but not the response to adenosine 3',5'-cyclic monophosphate (cAMP) or 8-BrcAMP, consistent with an effect on cAMP generation. To determine whether these effects were due to the EETs or to products of their metabolism, they examined the effects of their vicinal diol hydrolysis products, the dihydroxyeicosatrienoic acids. Nonenzymatic conversion of labeled 5,6-EET to its vicinal diol occurred rapidly in the buffer, whereas 11,12-EET was hydrolyzed in a saturable manner only when incubated in the presence of bladder tissue. The dihydroxyeicosatrienoic acids formed inhibited water flow in a manner paralleling that of the EETs. The data support the hypothesis that EETs and their physiologically active dihydroxyeicosatrienoic acid metabolites inhibit vasopressin-stimulated water flow predominantly via inhibition of adenylate cyclase

1987-01-01

187

Phylogeography of endemic toads and post-Pliocene persistence of the Brazilian Atlantic Forest.  

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The Plio-Pleistocene refugia hypothesis recently gained support in explaining Brazilian Atlantic Forest megadiversity from combined analyses of species paleodistributions and genetic diversity. Here we examine genetic differentiation and historical distributions in the Rhinella crucifer group of toads, endemic to and widely distributed within this biome. We analyzed sequences of mitochondrial (control region, ND1, and ND2) and nuclear (beta-crystallin and rhodopsin) DNA markers from 65 individuals representing five species. We found deep structure across the range at mitochondrial markers; genetic diversity is geographically structured in four main haplotype clades with the oldest divergence, dated to the Pliocene, between the southernmost populations and other regions of the species' range. Remaining populations are distributed in haplotype clades that may have diverged throughout the Pleistocene. Our paleoecological distribution models support a scenario of habitat fragmentation associated with glacial cycling, but we found limited congruence of phylogeographic patterns with the refugia. We found that some genetic breaks geographically coincide with putative barriers associated to neotectonic activity, but finer-scale sampling will be necessary to test the relative importance of distinct isolation mechanisms. Overall, the data refute the recently proposed hypothesis of a southern Holocene colonization of the Atlantic Forest from northern refugia, suggesting instead persistence of forested habitats in the south. Our unexpected results underscore the need to consider distinct organismal histories in planning biome-level conservation. We discuss species correspondence to clades recovered in our phylogenetic analyses. PMID:20139019

Thomé, Maria Tereza C; Zamudio, Kelly R; Giovanelli, João G R; Haddad, Célio F B; Baldissera, Flávio A; Alexandrino, João

2010-06-01

188

Phylogeography, geographic structure, genetic variation, and potential species boundaries in Philippine slender toads.  

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We investigated phylogeography of Philippine slender toads (genus Ansonia) and used a temporal framework for diversification, statistical tests of alternate topologies, and Bayesian approaches to test previous hypotheses concerning dispersal to, and colonization routes within, the southern Philippine island of Mindanao. Two species of Ansonia previously have been documented, with ranges separated by an east-west split corresponding to the approximate boundaries of Mindanao's paleoisland precursors. We present new mtDNA sequence data (1946 bp from genes encoding ND1, 16S rRNA and tRNALeu) for 105 Ansonia specimens sampled from 20 localities on Mindanao Island. Our data suggest that Philippine Ansonia is composed of at least eight, well-supported population lineages, structured into a minimum of four highly divergent mtDNA clades. One clade corresponds to Ansonia mcgregori, a range-restricted species apparently limited to the distal portion of the Zamboanga Peninsula of western Mindanao. Two morphologically indistinguishable, but genetically divergent, lineages possibly are undescribed cryptic species from western Mindanao. We recognize the five remaining lineages as Ansonia muelleri pending data from morphology or bioacoustics that might diagnose separate species among these lineages. Regardless of their species status, the five allopatric lineages of A. muelleri should be viewed as important genetic units for future genetic conservation planning. PMID:21757017

Sanguila, Marites Bonachita; Siler, Cameron D; Diesmos, Arvin C; Nuñeza, Olga; Brown, Rafe M

2011-11-01

189

Composition of fatty oils from semen ziziphi spinosae and its cardiotonic effect on isolated toad hearts.  

Science.gov (United States)

In this study, the composition of fatty oil from Semen Ziziphi Spinosae and its cardiotonic activity on the heart isolated from a toad were studied. Oil-in-water (O/W) emulsions of fatty oil were prepared by the perfusion method. The fatty oil had a positive inotropic effect on isolated rat hearts at a concentration between 5?×?10(-3) and 2?×?10(-2)?mL/10?mL, and the effect was in positive correlation with the concentration of calcium ions. In addition, this effect was inhibited by 2?mg/mL nifedipine, suggesting that the cardiotonic mechanism could be responsible for accelerating the inflow of calcium ions. Gas chromatography-mass spectrometry analysis showed that the main constituents of the fatty oil were 9-octadecenoic acid (43.32%), 9,12-octadecadienoic acid (42.57%), hexadecanoic acid (4.76%), 9-eicosenoic acid (2.95%), stearic acid (2.41%) and arachidic acid (0.81%). This preliminary study revealed that the fatty oil of Semen Ziziphi Spinosae exhibited remarkable cardiotonic activity in the tested models, and it is necessary to further reveal the effective substances of the fatty oil. PMID:21707231

Xie, Junbo; Zhang, Yanqing; Wang, Lijuan; Qi, Wuqin; Zhang, Mingchun

2012-01-01

190

Phylogenetic relationships of the mustache toads inferred from mtDNA sequences.  

Science.gov (United States)

Species of the genus Vibrissaphora are unique among all anurans in that males exhibit external cornified spines in the maxillary region during the breeding season. They were separated from species of the genus Leptobrachium based on this unique character. We construct a phylogeny using the 16S, ND4, and cytochrome b mitochondrial genes of 42 individuals from eight species of Vibrissaphora and five species of Leptobrachium from mainland China, Southeast Asia, and Hainan Island. Species of both Oreolalax and Scutiger were used as outgroups. The results indicate that: L. huashen and L. chapaense form a clade that is nested within Vibrissaphora, and L. hainanense is the sister taxon to the clade comprising all Vibrissaphora plus L. chapaense and L. huashen; V. boringiae is grouped with a clade consisting of V. leishanensis, V. liui, and V. yaoshanensis; and V. yaoshanensis is a species separate from V. liui. We propose taxonomic changes that reflect these findings. Also based on the resulting phylogenetic trees, we propose that the mustache toads originated in the trans-Himalayan region of southwest China, and that the evolution of maxillary spines, large body size, and reverse sexual size dimorphism in these frogs was influenced by intrasexual selection due to adopting a resource-defense polygyny mating system. PMID:18024176

Rao, Ding-Qi; Wilkinson, Jeffery A

2008-01-01

191

[Facilitation of cholinergic transmission by huperzine A in toad paravertebral ganglia in vitro].  

Science.gov (United States)

Using the intracellular recording techniques of toad paravertebral ganglia (PVG), the effects of cholinesterase inhibitor huperzine A (Hup-A), an alkaloid first isolated from Huperzia serrata (Thunb) Trev in China, on the synaptic transmission were studied. In 30 PVG cells tested, no remarkable changes in membrane potential and input resistance were observed during superfusion of Hup-A 0.3 or 1 mumol.L-1 for 15 min. The rate of orthodromic action potential evoked by preganglionic stimulation was increased by Hup-A 0.3 or 1 mumol.L-1 (n = 12, P < 0.05), and much faster, stronger, and longer in action at 50 or 100 mumol.L-1 (n = 11). The amplitude and duration of exogenous acetylcholine-, but not carbachol-, induced depolarization were increased (P < 0.05). It is concluded that Hup-A is a selective and potent cholinesterase inhibitor, by which action it facilitates the cholinergic transmission of PVG neurons. PMID:8010112

Zhang, G B; Wang, M Y; Zheng, J Q; Tang, X C

1994-03-01

192

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

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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

J. Procopio

1997-08-01

193

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.

Caramaschi, Ulisses.

194

Toddia sp., "corpúsculo paranuclear" no sangue de Leptodactylus e Bufo do Brasil: desenvolvimento e citoquímica / Toddia sp. a paranuclear corpuscle in the blood of Leptodactylus and Bufo of Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O gênero Toddia, criado por França 1911, para um organismo encontrado em eritrõcitos de um anfíbio anuro, tem estrutura particular e o problema de sua natureza (protozoário ou vírus) é discutido. Nosso resultados mostram reações Feulgen e Verde Metila positivas, principalmente no início da infecção. [...] Com o decorrer da infecção as partículas são, geralmente, maiores que aquelas observadas alguns dias após as inoculações, mas as reações citoquímicas citadas anteriormente são, em geral, negativas ou fracamente positivas. Os mesmos resultados foram obtidos quando empregamos Laranja de acridina para caracterização do DNA e esta técnica foi negativa para o RNA. Estudando o desenvolvimento deste organismo e seus efeitos infecciosos foram confirmados por inoculações experimentais. As alterações no sangue do hospedeiro foram observadas e notamos que o núclo dos eritrócitos é severamente alterado durante o desenvolvimento da infecção, que é geralmente, muito intensa, terminando com a morte do hospedeiro. As inoculações experimentais demonstraram a especificidade da infecção, e diante dos conhecimentos a respeito dos organismos deste gênero, discutimos o problema da criação de espécies. Abstract in english Toddia, a genus created by França 1911 for an organism found in the erythrocytes of an anuran amphibian, has a particular structure and the problem of its viral relationship of protozoa nature is an important point which has recently been discussed. Attempt to resolve this problem must be made using [...] ultrastructure and cytochemical studies. Our results have shown a Feulgen positive reaction and a Methyl-Green positive reaction for this organism, chiefly in the beginning of the infection. At the end of the infection the particles are greater than that in the beginning but the reactions above cited are generaly wakly positive or negative. We have also employed the Acridine orange method in the characterization of DNA and the results are positive too. Further histochemical studies are necessary to determine the true nature of the material observed in this study. We have also studied the development of this organism and its pathogenic effects have been confirmed by experimental inoculation. The alterations in the blood of the host were observed and we noted that the nucleus of the red blood cells is severely disturbed during the development of the infection. The experimental inoculation (in Leptodactylus and Bufo) have demonstred specific infectivety which is generaly hard, finishing with the death of the host. The taxonomic aspects related to this genus are discussed and the authors agree to the point of view of Mackerras 1961, and Marquardt 1967, about the identity of Pirhemocyton and Toddia. We need more research to stablish the viral nature of this organism.

Neize de Moura, Pereira; Sylvio Celso Gonçalves da, Costa; Maria Auxiliadora de, Sousa.

195

All-optical packet header and payload separation based on two TOADs for optical packet switched networks  

Science.gov (United States)

We present a novel all-optical header and payload separation technique that can be utilized in Un-Slotted optical packet switched networks. The technique uses two modified TOADs, one is for packet header extraction with differential modulation scheme and the other performs a simple XOR operation between the packet and its self-derived header to get the separated payload. The main virtue of this system is simple structure and low power consumption. Through numerical simulations, the operating characteristics of the scheme are illustrated. In addition, the system parameters are discussed and designed to optimize the performance of the proposed scheme.

Ji, Wei; Zhang, Min; Ye, Peida

2006-10-01

196

Genetic limits of thymic immunosuppression of anti-hapten antibody production in Xenopus laevis laevis, the South African clawed toad.  

Science.gov (United States)

Thymic immunosuppression in adult Xenopus laevis laevis, the South African clawed toad, is antigen-dependent and antigen-specific, but it is not genetically restricted. In this report, we show that combination in vitro with a thymus from an immunized Xenopus laevis laevis can suppress antibody production to a hapten from spleen fragments, if the spleen fragments are derived from a subspecies of Xenopus laevis or a species of Xenopus which shares the same diploid chromosome number (2N = 36). Some aspects of the evolution of thymic immunosuppression are considered in the light of these results. PMID:6707484

Ruben, L N; James, H S; Clothier, R H; Balls, M

1984-02-01

197

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

198

AVALIATION OF VENTILATORY PATTERN IN THE TOAD RHINELLA SCHNEIDERI (ANURA: BUFONIDAE  

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Full Text Available Amphibians ventilated their lungs by buccal pumping mechanism, which was first described in 1969 as a model for studying anurans respiration. Since amphibians do not have alveoli in their lungs, wecalculated to the toad Rhinella schneideri the equivalent lung ventilation from the equation VEFF = (VLCO2·RT/PLCO2. We analyzed buccal and pulmonary pressures, respiratory volumes, lung and buccalventilation, and ventilation frequency. [VE (12,1 ± 0,6ml BTPS.min-1.kg-1 ; VEB (164,3 ± 2,2ml BTPS.min-1.kg- 1 ; fR (5,8 ± 0,4min-1; buccal frequencies (68,5 ± 1,6min-1; Tidal volume(VT = 2.4 ml BTPS·kg-1]. The low oxygen extraction (17,3 ± 2,8% was used to explain the high frequency of pulmonary and buccal ventilation.Os anfíbios ventilam seus pulmões por meio de bombeamento bucal, mecanismo que foi primeiramente descrito 1969 como um modelo para a respiração de anuros. Como os anfíbios não possuem alvéolos em seus pulmões, foi calculado para o sapo Rhinella schneideri a ventilação equivalente do pulmão por meio da equação VEFF = (VLCO2·RT/PLCO2. Analisamos as pressões bucais e pulmonares, os volumes respiratórios, ventilação pulmonar e bucal, e frequências de ventilação. [VE (12,1 ± 0,6 ml BTPS.min-1.kg-1; VEB (164,3 ± 2,2 ml BTPS.min-1.kg-1; fR (5,8 ± 0,4 min -1; Freqüência bucal (68,5 ± 1,6 min-1; volume corrente(VT = 2,4 BTPS ml • kg-1]. A baixa extração de oxigênio (17,3% ± 2,8 foi utilizada para explicar a alta freqüência da ventilação pulmonar e bucal.

FERNANDES, Marcelo dos Santos

2010-11-01

199

76 FR 18576 - Endangered and Threatened Wildlife and Plants; Permits  

Science.gov (United States)

...take black-footed ferrets (Mustela nigripes) in conjunction with recovery activities...possess black-footed ferret (Mustela nigripes) and Wyoming toad (Bufo baxteri) for...possess black-footed ferret (Mustela nigripes) for public display and...

2011-04-04

200

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

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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

 
 
 
 
201

Miniaturized bioaffinity assessment coupled to mass spectrometry for guided purification of bioactives from toad and cone snail.  

Science.gov (United States)

A nano-flow high-resolution screening platform, featuring a parallel chip-based microfluidic bioassay and mass spectrometry coupled to nano-liquid chromatography, was applied to screen animal venoms for nicotinic acetylcholine receptor like (nAChR) affinity by using the acetylcholine binding protein, a mimic of the nAChR. The potential of this microfluidic platform is demonstrated by profiling the Conus textile venom proteome, consisting of over 1,000 peptides. Within one analysis (Bioactives from the toad samples were subsequently isolated by MS-guided fractionation. The fractions analyzed by NMR and a radioligand binding assay with ?7-nAChR confirmed the identity and bioactivity of several new ligands. PMID:24833338

Heus, Ferry; Otvos, Reka A; Aspers, Ruud L E G; van Elk, Rene; Halff, Jenny I; Ehlers, Andreas W; Dutertre, Sébastien; Lewis, Richard J; Wijmenga, Sybren; Smit, August B; Niessen, Wilfried M A; Kool, Jeroen

2014-01-01

202

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

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Abstract Background Captive breeding programs for endangered amphibian species often utilize exogenous hormones for species that are difficult to breed. The purpose of our study was to compare the efficacy of two different hormones at various concentrations on sperm production, quantity and quality over time in order to optimize assisted breeding. Methods Male American toads (Anaxyrus americanus) were divided into three separate treatment groups, with animals in each group rotated through dif...

Kouba, Andrew J.; Delbarco-trillo, Javier; Vance, Carrie K.; Milam, Callie; Carr, Meghan

2012-01-01

203

Regulation of the sodium permeability of the luminal border of toad bladder by intracellular sodium and calcium: role of sodium-calcium exchange in the basolateral membrane  

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Sodium movement across the luminal membrane of the toad bladder is the rate-limiting step for active transepithelial transport. Recent studies suggest that changes in intracellular sodium regulate the Na permeability of the luminal border, either directly or indirectly via increases in cell calcium induced by the high intracellular sodium. To test these proposals, we measured Na movement across the luminal membrane (th Na influx) and found that it is reduced when intracellular Na is increased...

1981-01-01

204

Molecular characterization of MHC class II in a nonmodel anuran species, the fire-bellied toad Bombina bombina.  

Science.gov (United States)

While the anuran Xenopus comprises one of the best characterized nonmammalian taxa regarding the major histocompatibility complex (MHC), the organization of this gene complex has never been studied in other anurans, and information on amphibian MHC (other than Xenopus) is generally very scarce. Here, we describe the characterization of the first MHC class II B cDNA sequences from a nonmodel anuran species, the European fire-bellied toad (Bombina bombina). We isolated two transcript sequences differing substantially in amino acid composition and length within the beta2 domain. To investigate the variability of the peptide binding region in this species, we sequenced a 158-bp large fragment from wild B. bombina (n = 20) and identified eight distinct alleles. All substitutions but one were nonsynonymous, and many of the highly polymorphic sites corresponded with amino acid positions known to be involved in antigen binding. The level of variation we found in B. bombina was similar compared to that previously found in a comparable sample of a wild urodelan species, Ambystoma tigrinum, and to that found in Xenopus laevis. Based on the cDNA data and the individual's allelic diversity, we conclude that Bombina possesses at least two class II B loci. With our new beta1 primers, we were able to generate sequences in other species of anurans. We provide here a first phylogenetic analysis of this gene in amphibians. PMID:17406862

Hauswaldt, J Susanne; Stuckas, H; Pfautsch, S; Tiedemann, R

2007-06-01

205

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

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

Kouba Andrew J

2012-08-01

206

Role of prostaglandin E2 in mediating the effects of pH on the hydroosmotic response to vasopressin in the toad urinary bladder.  

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Acidosis inhibits the hydroosmotic response to vasopressin. Since prostaglandins are known to modulate vasopressin-stimulated water flow we investigated the role of endogenous prostaglandin E2(PGE2) production in the pH-dependent response of the toad urinary bladder to vasopressin. Graded acidification of the serosal medial resulted in a progressive decline in vasopressin-stimulated water flow from 26.6 +/- 0.5 mg/min at pH 8.4 to 1.7 +/- 0.6 at pH 6.9. In these bladders basal PGE2 synthesis ...

1982-01-01

207

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

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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 co...

Ferreira, Rodrigo B.; Teixeira, Roge?rio L.

2009-01-01

208

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

209

Murine and human interleukin 2 can substitute for the thymus in immune responses to TNP-Ficoll in Xenopus laevis, the South African clawed toad.  

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Extirpation of the thymuses of Xenopus laevis abrogates the capacity to respond to trinitrophenol (TNP)-Ficoll regardless of the age of the animal. This thymus requirement can be substituted for by a variety of treatments which stimulate thymus-derived (T)cell activity in the periphery, such as the rejection of allogeneic skin grafts, immunologic challenge with thymus-dependent immunogens, (e.g., heterologous erythrocytes), or plant-derived lectins (e.g., concanavalin A). Here we report that interleukin 2 (IL-2), a T-cell-produced hormone of mammalian origin also substitutes for this thymus requirement in thymectomized toads. PMID:3873289

Ruben, L N; Clothier, R H; Balls, M

1985-06-01

210

Light regulation of cGMP metabolism in toad rod outer segments (ROS) deduced from intact photoreceptor and cellfree kinetics  

International Nuclear Information System (INIS)

The rate of cGMP hydrolysis by phosphodiesterase (PDE) in intact ROS, monitored in dark-adapted isolated toad retina by the rate of 18O appearance in guanine nucleotide ?-phosphoryls, is 1/360th of that observed in disrupted ROS at a substrate concentration equivalent to the total [cGMP] in ROS. Low to moderate photic stimuli increase this cGMP hydrolytic rate up to 10-fold in intact ROS with little or no change in total [cGMP]. G-protein activation determined in intact ROS by the fraction of GDP labeled with 18O corresponds with light-related increases in cGMP flux. In contrast, relatively high intensities and extended illumination cause attenuation of maximal cGMP hydrolysis with proportionate reductions in total [cGMP]. From these observations combined with the effects of activated G-protein on kinetics and cGMP binding of ROS PDE the following model for light-regulation of cGMP metabolism was deduced: cGMP flux in intact ROS is severely restricted in the dark state because approximately 99% of the cGMP is bound to high affinity sites on the non-stimulated form of PDE. This constraint is relieved when activated G-protein converts the cGMP-binding form of PDE to a high K/sub m/ catalytic form. cGMP is then redistributed to a dynamic pool where it is available to PDE catalytic sites and lower affinity allosteric sites. The [cGMP] in the dynamic pool is maintained or further increased or decreased by modulating the activity of an apparently light-sensitive guanylyl cyclase

1987-05-01

211

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1988-06-25

212

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

International Nuclear Information System (INIS)

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

1988-06-25

213

Population Structure, Historical Biogeography and Demographic History of the Alpine Toad Scutiger ningshanensis in the Tsinling Mountains of Central China  

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

Meng, Hongzhe; Li, Xiaochen; Qiao, Penghai

2014-01-01

214

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

Science.gov (United States)

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

Procopio, J; Lacaz-Vieira, F

1990-07-01

215

Climate Change and the Distribution of Neotropical Red-Bellied Toads (Melanophryniscus, Anura, Amphibia): How to Prioritize Species and Populations?  

Science.gov (United States)

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

Zank, Caroline; Becker, Fernando Gertum; Abadie, Michelle; Baldo, Diego; Maneyro, Raul; Borges-Martins, Marcio

2014-01-01

216

Genetic Variation among various populations of spadefoot toads (Pelobates syriacus, Boettger, 1869 at breeding sites in northern Israel  

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Full Text Available A genetic study was carried out on spadefoot toads (Pelobates syriacus from habitats of various locations and altitudes in northern Israel. Cytochrome b and 12S were amplified by PCR for the analysis of genetic variation based on five DNA polymorphisms and for RAPD PCR. The nucleotide sequences of the mitochondrial DNA fragments were determined from a 460 bp clone of cytochrome b and a 380 bp clone of 12S (GenBank accession numbers, FJ595199-FJ59-5203. No genetic variation was found among the populations with regard to 12S. According to the analysis of five sequences using Arlequin software, there was a high gene identity among the populations (98.7%-99.6%. Both populations, Elrom Pond breeding site, at the highest altitude and Fara Pond, at the lowest, had the lowest identities as compared to other populations. The DNA variation among P. syri-acus populations from various breeding sites, according to band sharing (BS, when using the OP-4 primer, was 0.92-1.00. Similarity was low between the population of Elrom Pond and the populations of Kash Pond, Raihania Pond and Sasa Pond (0.92 BS, as well as between the population of Fara Pond at the lowest altitude, and the populations of Kash Pond, Raihania Pond and Sasa Pond (0.92 BS. Similar results were obtained when comparing the results obtained using primer OPA-3. The lowest similarity was found between populations of the highest altitude (Elrom Pond and lowest altitude (Fara Pond, relative to the other ponds (Kash Pond, Raihania Pond and Sasa Pond with a BS of 0.93.

Gad Degani

2013-10-01

217

The interactive effect of an emerging infectious disease and an emerging contaminant on Woodhouse's toad (Anaxyrus woodhousii) tadpoles.  

Science.gov (United States)

Two factors that influence amphibian population declines are infectious diseases and exposure to anthropogenic contaminants. The authors examined an emerging fungal pathogen, Batrachochytrium dendrobatidis (Bd), and its interaction with an emerging contaminant, the antimicrobial triclosan. They first conducted a 2?×?2?×?4 factorial study to examine the interactive impacts of dragonfly predator cues, Bd, and triclosan (0?µg/L, 10?µg/L, 100?µg/L, and 1000?µg/L) on Woodhouse's toad (Anaxyrus woodhousii) tadpoles. The authors measured the lethal and sublethal impacts of these stressors on tadpoles over 4 wk. All tadpoles in the 100-µg/L and 1000-µg/L concentrations of triclosan died within 24?h of exposure, but tadpoles in the low concentration (10?µg/L) survived. Tadpoles exposed to only Bd (no triclosan) exhibited a low survival rate (67.5%), whereas those exposed to both 10?µg/L triclosan and Bd exhibited a high survival rate (91.1%), implying that triclosan inhibits effects of Bd on tadpoles. Batrachochytrium dendrobatidis and predator cue exposure individually increased the developmental rate of the surviving tadpoles, but this effect was absent when these factors were combined with triclosan. In a follow-up study, the authors found Bd growth in culture was significantly inhibited at the 10-µg/L concentration of triclosan and completely inhibited at 100?µg/L. These findings suggest that interactions among multiple stressors can be complex and require examination in conjunction with one another to evaluate actual impacts to aquatic fauna. PMID:23637083

Brown, Jennifer R; Miiller, Tyler; Kerby, Jacob L

2013-09-01

218

Disruption of excitation-contraction coupling and titin by endogenous Ca2+-activated proteases in toad muscle fibres.  

Science.gov (United States)

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

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

2005-05-01

219

Outcrop analysis of trace fossil assemblages in the Toad Formation (Triassic), SE Yukon Territory : implications for hydrocarbon exploration in NE British Columbia  

Energy Technology Data Exchange (ETDEWEB)

Hydrocarbon producing strata is often characterized by trace fossil assemblages, but trace fossils are not always available for core-based sub surfaces. Therefore, it is a good idea to integrate outcrop and subsurface ichnological studies to make better use of subsurface data. Strata of the Lower Triassic Toad Formation in the southeastern region of the Yukon Territory consists of inter bedded shale, siltstone, and sandstone. The rocks contain a diverse assemblage of well-preserved trace fossils. Five facies associations have been recognized within the stratigraphic sequence. They reveal that the rocks were deposited on a wave-dominated shelf. In distal shelf facies, the trace fossil diversity is low, but is moderate to high in offshore to shoreface strata. The most common ichno fossils are burrow networks and simple infaunal burrows. Arthropods make up much of the ichno fauna. It was noted that the sediments and trace fossil assemblages of the Toad Formation in the La Biche River area are similar to the gas producing strata of the Montney Formation of northeastern British Columbia. The Yukon succession can potentially be used to model that of British Columbia.

MacNaughton, R.B.; Zonneveld, J.P.; Utting, J. [Geological Survey of Canada, Calgary, AB (Canada)

2002-07-01

220

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.

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

 
 
 
 
221

Species delineation using Bayesian model-based assignment tests: a case study using Chinese toad-headed agamas (genus Phrynocephalus  

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Full Text Available Abstract Background Species are fundamental units in biology, yet much debate exists surrounding how we should delineate species in nature. Species discovery now requires the use of separate, corroborating datasets to quantify independently evolving lineages and test species criteria. However, the complexity of the speciation process has ushered in a need to infuse studies with new tools capable of aiding in species delineation. We suggest that model-based assignment tests are one such tool. This method circumvents constraints with traditional population genetic analyses and provides a novel means of describing cryptic and complex diversity in natural systems. Using toad-headed agamas of the Phrynocephalus vlangalii complex as a case study, we apply model-based assignment tests to microsatellite DNA data to test whether P. putjatia, a controversial species that closely resembles P. vlangalii morphologically, represents a valid species. Mitochondrial DNA and geographic data are also included to corroborate the assignment test results. Results Assignment tests revealed two distinct nuclear DNA clusters with 95% (230/243 of the individuals being assigned to one of the clusters with > 90% probability. The nuclear genomes of the two clusters remained distinct in sympatry, particularly at three syntopic sites, suggesting the existence of reproductive isolation between the identified clusters. In addition, a mitochondrial ND2 gene tree revealed two deeply diverged clades, which were largely congruent with the two nuclear DNA clusters, with a few exceptions. Historical mitochondrial introgression events between the two groups might explain the disagreement between the mitochondrial and nuclear DNA data. The nuclear DNA clusters and mitochondrial clades corresponded nicely to the hypothesized distributions of P. vlangalii and P. putjatia. Conclusions These results demonstrate that assignment tests based on microsatellite DNA data can be powerful tools for distinguishing closely related species and support the validity of P. putjatia. Assignment tests have the potential to play a significant role in elucidating biodiversity in the era of DNA data. Nonetheless, important limitations do exist and multiple independent datasets should be used to corroborate results from assignment programs.

Fu Jinzhong

2010-06-01

222

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

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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

223

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.

224

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

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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

225

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

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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

226

Myiasis by Lucilia silvarum (Calliphoridae) in amphibian species in boreal Alberta, Canada.  

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We report myiasis by Lucilia silvarum with an overall prevalence of 0.9% in amphibian populations in boreal Alberta. In the period 1998--1999, we documented L. silvarum infestations in wild populations of wood frog (Rana sylvatica), boreal chorus frog (Pseudacris maculata), boreal toad (Bufo boreas boreas), and Canadian toad (B. hemiophrys). We believe this is the first record of this parasite from boreal and Canadian toads. Almost all previous records of L. silvarum parasitism in North America indicate that myiasis is fatal to an anuran host. Here, we provide the first record of adult individuals from 2 species (wood frog and boreal toad) surviving infestations. Although we actively captured and examined amphibians in Alberta from 1996 to 2006, we only found parasitism in 1998 and 1999. This is the most northerly record of anuran infestations by this parasite. PMID:18576743

Eaton, Brian R; Moenting, Alissa E; Paszkowski, Cynthia A; Shpeley, Danny

2008-08-01

227

Microbial Specificity of Metallic Surfaces Exposed to Ambient Seawater  

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High-molecular-weight materials associated with the extracellular matrix and film found on titanium and aluminum surfaces after exposure to flowing coastal seawater were isolated. This material was purified by hydroxylapatite chromatography and subsequently employed to produce antibodies in the toad, Bufo marinus. The antibodies were immobilized on a solid support and employed to isolate adhesion-enhancing, high-molecular-weight materials from the laboratory culture media of bacterial strains...

1984-01-01

228

Coincident mass extirpation of neotropical amphibians with the emergence of the infectious fungal pathogen Batrachochytrium dendrobatidis  

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Amphibians highlight the global biodiversity crisis because ?40% of all amphibian species are currently in decline. Species have disappeared even in protected habitats (e.g., the enigmatic extinction of the golden toad, Bufo periglenes, from Costa Rica). The emergence of a fungal pathogen, Batrachochytrium dendrobatidis (Bd), has been implicated in a number of declines that have occurred in the last decade, but few studies have been able to test retroactively whether Bd emergence was linked...

Cheng, Tina L.; Rovito, Sean M.; Wake, David B.; Vredenburg, Vance T.

2011-01-01

229

Can Differences in Host Behavior Drive Patterns of Disease Prevalence in Tadpoles?  

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Differences in host behavior and resistance to disease can influence the outcome of host-pathogen interactions. We capitalized on the variation in aggregation behavior of Fowler's toads (Anaxyrus [?=?Bufo] fowleri) and grey treefrogs (Hyla versicolor) tadpoles and tested for differences in transmission of Batrachochytrium dendrobatidis (Bd) and host-specific fitness consequences (i.e., life history traits that imply fitness) of infection in single-species amphibian mesocosms. On average, ...

Venesky, Matthew D.; Kerby, Jacob L.; Storfer, Andrew; Parris, Matthew J.

2011-01-01

230

Perpetual production of hair cells and maturational changes in hair cell ultrastructure accompany postembryonic growth in an amphibian ear.  

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Sensory hair cells are produced in the ears of birds and mammals only during early development, so that a programmed termination of hair cell proliferation leaves adult birds and mammals susceptible to irreversible deafness and balance disorders. This study reports that this is not an inherent feature of hair cells and is not shared through all the vertebrate classes. In toads (Bufo marinus) hair cells accumulate throughout life, increasing in the sacculus from approximately 400 cells at meta...

Corwin, J. T.

1985-01-01

231

Slowing of velocity during isotonic shortening in single isolated smooth muscle cells. Evidence for an internal load  

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In single smooth muscle cells, shortening velocity slows continuously during the course of an isotonic (fixed force) contraction (Warshaw, D.M. 1987. J. Gen. Physiol. 89:771-789). To distinguish among several possible explanations for this slowing, single smooth muscle cells were isolated from the gastric muscularis of the toad (Bufo marinus) and attached to an ultrasensitive force transducer and a length displacement device. Cells were stimulated electrically and produced maximum stress of 1...

1990-01-01

232

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

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

1986-01-01

233

Anti-inflammatory Steroid (Prednisolone) and its Effect on the Adrenal Gland  

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Administration of an anti-inflammatory steroidal drug prednisolone- (0.85 mg/ kg body weight daily for 10 days) to adult toads Bufo tibamicus resulted in suppression of the function of the adrenal gland, as shown by a significant increase in the lipid droplets, autolysis of mitochondria and disorganization and degranulation of ER in the steriodogenic cells. Furthermore, chromaffin cells (catecholamines secreting cells), showed a marked decrease in the number of chronaffin granules and ...

Essay, A. E.; Sakr, S. A.; Saleh, A. T.; El-salmy, F.

2000-01-01

234

Polymorphism in purified guanylate cyclase from vertebrate rod photoreceptors.  

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Guanylate cyclase from rod photoreceptors of amphibian (toad, Bufo marinus, and frog, Rana catesbeiana) and bovine retinas was solubilized and purified by a single chromatography step on a GTP-agarose column. Silver staining of purified amphibian enzymes in SDS/polyacrylamide gels disclosed a doublet band (110 and 115 kDa), while the bovine enzyme appeared as a singlet band (110 kDa). The identification of these guanylate cyclases was confirmed using three chromatography systems with the puri...

1991-01-01

235

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

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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

236

Glutathione transferase isoenzymes from frog (Xenopus laevis) liver and embryo.  

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The expression of glutathione transferase isoenzymes has been investigated in embryo and adult liver of the frog Xenopus laevis. By analysing the GST isoenzymes recovered from GSH-affinity chromatography in terms of electrophoretic mobility, HPLC elution profile, immunological reactivity, N-terminal amino acid sequence and mass spectrometry molecular mass no significant difference in the GST subunit composition between embryos and liver was found. In both tissues the same three subunits, showing similarity to mu, alpha and sigma class GSTs, are present. These results, together with those previously reported for toad (Bufo bufo), strongly support the notion that the transition from an aquatic environment to a terrestrial atmosphere containing high oxygen concentration has accompanied specific GST gene expression. PMID:11853961

Angelucci, Stefania; Sacchetta, Paolo; De Luca, Antonella; Moio, Pasquale; Amicarelli, Fernanda; Di Ilio, Carmine

2002-01-15

237

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

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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

238

Toxicity of road salt to Nova Scotia amphibians.  

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The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC(50)) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species. PMID:18684543

Collins, Sara J; Russell, Ronald W

2009-01-01

239

Juvenile amphibians do not avoid potentially lethal levels of urea on soil substrate.  

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We examined the effects of a forest fertilizer (urea) on newly metamorphosed terrestrial amphibians (Western toads, Bufo boreas; Cascades frogs, Rana cascadae; long-toed salamanders, Ambystoma macrodactylum; and roughskin newts, Taricha granulosa). We examined avoidance behavior of Western toads and Cascades frogs on both paper towel and soil substrates dosed with urea (control and 100 kg N/ha and an additional treatment of 50 kg N/ha for Western toads on soil substrate) and avoidance behavior of long-toed salamanders on soil substrate dosed with urea. We further examined the survival and feeding behavior of all four species exposed to urea on soil substrate (100 kg N/ha) for 5 d. Juvenile Western toads and Cascades frogs avoided paper towels dosed with urea but did not avoid urea-dosed soil substrate. However, Western toads and Cascades frogs both suffered significant mortality when exposed to urea on a soil substrate for 5 d. Furthermore, after adjusting for weight, we found that urea-exposed juvenile Western toads and Cascades frogs consumed significantly fewer prey items (crickets) compared with nonexposed control animals. Long-toed salamanders did not discriminate against soil substrate dosed with urea, and neither long-toed salamanders nor roughskin newts died or reduced prey consumption as a result of urea exposure. Juvenile amphibians may not be able to detect and avoid harmful levels of urea fertilizer on a natural substrate. Furthermore, anthropogenic stressors such as urea fertilizer can significantly reduce the survival and prey consumption of juvenile amphibians. These effects are important to consider in light of possible threats to the conservation status of many amphibian species. PMID:11596767

Hatch, A C; Belden, L K; Scheessele, E; Blaustein, A R

2001-10-01

240

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

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Water molds attack aquatic eggs worldwide and have been associated with major mortality events in some cases, but typically only in association with additional stressors. We combined field observations and laboratory experiments to study egg stage defenses against pathogenic water mold in three temperate amphibians. Spotted salamanders (Ambystoma maculatum) wrap their eggs in a protective jelly layer that prevents mold from reaching the embryos. Wood frog (Rana sylvatica) egg masses have less jelly but are laid while ponds are still cold and mold growth is slow. American toad (Bufo americanus) eggs experience the highest infection levels. They are surrounded by thin jelly and are laid when ponds have warmed and mold grows rapidly. Eggs of all three species hatched early when infected, yielding smaller and less developed hatchlings. This response was strongest in B. americanus. Precocious hatching increased vulnerability of wood frog hatchlings to invertebrate predators. Finally, despite being potential toad hatchling predators, R. sylvatica tadpoles can have a positive effect on B. americanus eggs. They eat water mold off infected toad clutches, increasing their hatching success. PMID:17089665

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

2006-10-01

 
 
 
 
241

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

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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

242

Acid-precipitation studies in Colorado and Wyoming: Interim report of surveys of Montane amphibians and water chemistry. Interim report, 1986-1988  

Energy Technology Data Exchange (ETDEWEB)

Surveys for amphibians were conducted in the Rocky Mountains of northern Colorado and southern Wyoming from 1986 to 1988. The northern leopard frog (Rana pipiens) was present at only 12% of historically known localities, and the boreal toad (Bufo boreas) was present at 17% of known localities. Chorus frogs (Pseudacris triseriata) suffered a catastrophic decline in population size in one population monitored since 1961, but regionally, this species was observed in 64% of known localities. Tiger salamanders (Ambystoma tigrinum) and wood frogs (Rana sylvatica) were present at 45% and 69% of known localities respectively. Acid neutralizing capacity, pH, specific conductivity, and cation concentrations in water at amphibian localities were negatively correlated with elevation. Survival of wood frog embryos declined when exposed to aluminum concentrations.

Corn, P.S.; Stolzenburg, W.; Bury, R.B.

1989-06-01

243

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

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Full Text Available 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

1998-01-01

244

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

245

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

246

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-10-15

247

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. 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

2007-10-15

248

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

Science.gov (United States)

Effective management of wetland quantity and quality is crucial for effective conservation of declining amphibian populations. In particular, frogs and toads that employ aggregative breeding strategies may suffer negative population impacts in response to changes in availability of aquatic breeding habitat, including overabundance of suitable habitat, if density of conspecifics attending aggregations is positively correlated with reproductive success. Here we document such a positive relationship, potentially the first example of a component Allee effect in an anuran, in the critically endangered Houston toad (Bufo houstonensis). We assessed the relationship between mean yearly chorus size and reproductive success of males at the pond level using an information theoretic model selection approach and a two-sample t-test. The chosen model contained the single variable of mean yearly chorus size to predict probability of reproduction, as selected using the Akaike Information Criterion corrected for small sample size and Akaike weight. Mean chorus sizes were significantly higher among ponds exhibiting evidence of reproduction than in those that showed no evidence of reproduction. Our results suggest that chorusing alone is a poor proxy for inference of population stability and highlight a need for reassessment of widely-used amphibian monitoring protocols. Further, amphibian conservation efforts should account for potential Allee effects in order to optimize benefits and avoid underestimating critical population thresholds, particularly in species exhibiting rapid population declines. PMID:20404930

Gaston, Michele A; Fuji, Akiko; Weckerly, Floyd W; Forstner, Michael R J

2010-01-01

249

Soil-food chain-pesticide wildlife relationships in aldrin-treated fields  

Science.gov (United States)

Soil-food-chain-pesticide wildlife relationships were investigated to learn the concentration of pesticide residues present in soils, macro-invertebrates, vertebrates, and seeds as a result of annual applications of aldrin at recommended rates for pest control. Two central Missouri cornfields treated witb aldrin at 1 lb/acre, for 16 and 15 of the past 17 years, were selected for study during 1965-67. Primary samples collected for residue analyses included soils, earthworms (Lumbricidae), crickets (GryIlidae), and two kinds of ground beetles (Carabidae) obtained during early April, June, August, and October. Vertebrates and plant seeds collected during 1967 included white-footed mice (Peromyscus maniculatus), toads (Bufo americanus), snakes (Thamnophis sirtalis and Pituophis sayi), corn (Zea Mays), foxtail (Setaria Faberii), and annual sunflower (Helianthus annuus). Pesticide residues consisted primarily of dieldrin, the degradation product of aldrin. Combined aldrin and dieldrin residues, as two field all-season averages, wet weight basis, were: soils, 0.31 ppm; earthworms, 1.49 ppm; crickets, 0.23 ppm; Harpalus ground beetles, 1.10 ppm; Poecilus ground beetles, 9.67 ppm; white-footed mice, 0.98 ppm; toads, 3.53 ppm; garter snakes, 12.35 ppm; and corn, foxtail, and sunflower seeds less than 0.02 ppm each. Unusually high average residues (37.48 ppm) in Poecilus beetles during June, 1967, were attributed to abnormally high soil moisture and predacious feeding habits of these insects.

Korschgen, L.J.

1970-01-01

250

Toxicity of road salt to Nova Scotia amphibians  

Energy Technology Data Exchange (ETDEWEB)

The deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. In northern latitudes, a major pollutant in runoff water is salt (NaCl), used as de-icing agents. In this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. Acute toxicity tests (LC{sub 50}) were performed on five locally common amphibian species using a range of environmentally significant NaCl concentrations. Field surveys indicated that spotted salamanders (Ambystoma maculatum) and wood frogs (Rana sylvatica) did not occupy high chloride ponds. American toads (Bufo americanus) showed no pond preference based on chloride concentration. Acute toxicity tests showed spotted salamanders and wood frogs were most sensitive to chloride, and American toads were the least. Spring peepers (Pseudacris crucifer) and green frogs (Rana clamitans) showed intermediate sensitivities. We concluded that chloride concentrations in ponds due to application of de-icing salts, influenced community structure by excluding salt intolerant species. - Salt toxicity is presented as a mechanism affecting the distribution of amphibians and structure of amphibian communities in roadside wetlands.

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

2009-01-15

251

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

2009-01-01

252

Helminth communities in five species of sympatric amphibians from three adjacent ephemeral ponds in southeastern Wisconsin.  

Science.gov (United States)

Representatives of 5 amphibian species (313 individuals), including eastern American toads (Bufo americanus), wood frogs (Rana sylvatica), spring peepers (Pseudacris crucifer), blue-spotted salamanders (Ambystoma laterale), and central newts (Notophthalmus viridescens louisianensis), were collected from 3 ephemeral ponds during spring 1994, and they were inspected for helminth parasites. The component communities of anurans were more diverse than those of caudates. Infracommunities of all host species were isolationist and depauperate, due mostly to host ectothermy and low vagility. Toad infracommunities were dominated by skin-penetrating nematodes, and they had the highest values of mean total parasite abundance, mean species richness, and overall prevalence. This was likely due to their greater vagility compared with other host species. Infracommunities of wood frogs and blue-spotted salamanders had intermediate values for these measures of parasitism, whereas spring peeper and newt infracommunities had the lowest values. In addition to relative vagility, feeding habits and habitat preference were likely important in helminth community structure. Body size also seemed to play a role because mean wet weight of host species followed the same general trend as values of parasitism. However, effects of size were variable within host species and difficult to separate from other aspects of host ecology. PMID:17918353

Yoder, H Randall; Coggins, James R

2007-08-01

253

Blind location and separation of callers in a natural chorus using a microphone array.  

Science.gov (United States)

Male frogs and toads call in dense choruses to attract females. Determining the vocal interactions and spatial distribution of the callers is important for understanding acoustic communication in such assemblies. It has so far proved difficult to simultaneously locate and recover the vocalizations of individual callers. Here a microphone-array technique is developed for blindly locating callers using arrival-time delays at the microphones, estimating their steering-vectors, and recovering the calls with a frequency-domain adaptive beamformer. The technique exploits the time-frequency sparseness of the signal space to recover sources even when there are more sources than sensors. The method is tested with data collected from a natural chorus of Gulf Coast toads (Bufo valliceps) and Northern cricket frogs (Acris crepitans). A spatial map of locations accurate to within a few centimeters is constructed, and the individual call waveforms are recovered for nine individual animals within a 9 x 9 m(2). These methods work well in low reverberation when there are no reflectors other than the ground. They will require modifications to incorporate multi-path propagation, particularly for the estimation of time-delays. PMID:19640054

Jones, Douglas L; Ratnam, Rama

2009-08-01

254

Blind location and separation of callers in a natural chorus using a microphone array  

Science.gov (United States)

Male frogs and toads call in dense choruses to attract females. Determining the vocal interactions and spatial distribution of the callers is important for understanding acoustic communication in such assemblies. It has so far proved difficult to simultaneously locate and recover the vocalizations of individual callers. Here a microphone-array technique is developed for blindly locating callers using arrival-time delays at the microphones, estimating their steering-vectors, and recovering the calls with a frequency-domain adaptive beamformer. The technique exploits the time-frequency sparseness of the signal space to recover sources even when there are more sources than sensors. The method is tested with data collected from a natural chorus of Gulf Coast toads (Bufo valliceps) and Northern cricket frogs (Acris crepitans). A spatial map of locations accurate to within a few centimeters is constructed, and the individual call waveforms are recovered for nine individual animals within a 9×9 m2. These methods work well in low reverberation when there are no reflectors other than the ground. They will require modifications to incorporate multi-path propagation, particularly for the estimation of time-delays.

Jones, Douglas L.; Ratnam, Rama

2009-01-01

255

Density dependence in the terrestrial life history stage of two anurans.  

Science.gov (United States)

Populations of species with complex life cycles have the potential to be regulated at multiple life history stages. However, research tends to focus on single stage density-dependence, which can lead to inaccurate conclusions about population regulation and subsequently hinder conservation efforts. In amphibians, many studies have demonstrated strong effects of larval density and have often assumed that populations are regulated at this life history stage. However, studies examining density regulation in the terrestrial stages are rare, and the functional relationships between terrestrial density and vital rates in amphibians are unknown. We determined the effects of population density on survival, growth and reproductive development in the terrestrial stage of two amphibians by raising juvenile wood frogs (Rana sylvatica) and American toads (Bufo americanus) at six densities in terrestrial enclosures. Density had strong negative effects on survival, growth and reproductive development in both species. We fitted a priori recruitment functions to describe the relationship between initial density and the density of survivors after one year, and determined the functional relationship between initial density and mass after one year. Animals raised at the lowest densities experienced growth and survival rates that were over twice as great as those raised at the highest density. All female wood frogs in the lowest density treatment showed signs of reproductive development, compared to only 6% in the highest density treatment. Female American toads reached minimum reproductive size only at low densities, and male wood frogs and American toads reached maturity only in the three lowest density treatments. Our results demonstrate that in the complex life cycle of amphibians, density in the terrestrial stage can reduce growth, survival and reproductive development and may play an important role in amphibian population regulation. We discuss the implications of these results for population regulation in complex life cycles and for amphibian conservation. PMID:17622562

Harper, Elizabeth B; Semlitsch, Raymond D

2007-10-01

256

Ecology of anuran populations inhabiting thermally stressed aquatic ecosystems, with emphasis on larval Rana pipiens and Bufo terrestris  

International Nuclear Information System (INIS)

Field and laboratory studies were conducted to determine the responses of anuran populations to thermally stressed aquatic ecosystems. Adult and larval amphibians were sampled in and around a cool arm of a 67 ha reservoir that receives high temperature effluent from a nuclear production reactor on the Savannah River Plant (SRP) in South Carolina. Patterns for some species were compared with data from nearby unheated areas and analyzed in terms of the thermal gradient (16-45 C) extending the length of the reservoir's cool arm. The adaptation to breeding during nocturnal rainfall fortuitously confers a double advantage especially to anurans breeding in thermally stressed waters. (U.S.)

1974-01-01

257

Analysis of the displacement of five iberian anuran species in stress conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study describes the movement paths -in situation of stress- of five anuran species (Alytes obstetricans, Pelobates cultripes, Bufo bufo, Bufo calamita and Bufo viridis balearicus) by trajectometric analysis. Different experimental treatments (artificial vs. natural) and seasonal variations were studied. The path structure reflects specific (phyogenetic) constraints. Each species showed a characteristic pattern of locomotion for different experimental situations and seasons.

Sanuy Castells, Delfi?

1998-01-01

258

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

Science.gov (United States)

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. PMID:24677177

Weber, Roy E

2014-07-01

259

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 (â??H (O)) may, however, become maladaptive, as in cold-tolerant ungulates where it may hamper O2 unloading in cold extremities and commonly is mitigated by an 'additional' chloride-binding site that decreases the temperature effect by increasing the endothermic release of Cl(-) ions upon O2 binding. Since no previous studies have focused on the consequences of reduced Cl(-) binding, I report and compare the enthalpic effects of chloride ions and the allosteric effector, ATP, on Hbs of the high-altitude aquatic Andean frog Telmatobius peruvianus that lacks the α-chain chloride-binding site, and the lowland (sub-)tropical frog Xenopus laevis that has retained this site and exhibits high chloride sensitivity. In contrast to Xenopus, Telmatobius Hb exhibits high temperature sensitivity (high negative â??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 [(â??H' â?? -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; Weber, Roy E.

2014-01-01

260

A curious case of herbivory 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

2012-01-01

 
 
 
 
261

Biochemical parameters during reproduction of the toad fish, Halobatrachus didactylus (Schneider, 1801)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

[EN] Duringreproduction of Halobatrachus didactylus there are variations in thegonadosomatic and hepatosomatic indices. These variations are more marked infemales, with maximal values at the end of oogenesis and spermatogenesis. Serumcalcium concentration showed significant differences (P < 0.01), with highervalues in females and specially during the reproductive period (from January toApril). Hepatic and gonadal proteins also reach their maximum values in thisperiod. In gonads of both sexes ...

Rosety, Manuel; Blanco, Miguel; Gonza?lez Canales, Mari?a Luisa; Grau, Amalia; Sarasquete, Carmen

1992-01-01

262

The influence of muscle length on the development of fatigue in toad sartorius  

Science.gov (United States)

1. Fatigue curves were obtained on muscles contracting at length (L) different from the optimal (Lo), and performing isometric tetani of fixed duration at regular intervals. Every sixth tetanus occurred at Lo, the remainder took place at L. The parameters of the fatigue curve were compared with those of controls contracting always at Lo. Fatigability was measured as the coefficient of exponential decrease of tension with time. 2. Fatigability varied linearly with length in shortened and lengthened muscles, but the slopes of the relations were significantly different for the two groups. 3. The tension values from single experimental muscles fell on two independent curves, one for those obtained at Lo, another for data at L. The same muscle showed, therefore, two different fatigue processes which followed independent temporal evolutions. 4. Points 2 and 3 of this Summary imply that fatigue is a process dependent on the actual setting of the myofilaments during contraction and not distributed uniformly within the sarcomere. 5. It is proposed that fatigue results from local changes taking place at discrete reactive points in the myofilament. The experimental results are discussed in terms of this hypothesis and of the sliding model of contraction.

Aljure, Emilio F.; Borrero, Luis M.

1968-01-01

263

The influence of muscle length on the development of fatigue in toad sartorus.  

Science.gov (United States)

1. Fatigue curves were obtained on muscles contracting at length (L) different from the optimal (L(o)), and performing isometric tetani of fixed duration at regular intervals. Every sixth tetanus occurred at L(o), the remainder took place at L. The parameters of the fatigue curve were compared with those of controls contracting always at L(o). Fatigability was measured as the coefficient of exponential decrease of tension with time.2. Fatigability varied linearly with length in shortened and lengthened muscles, but the slopes of the relations were significantly different for the two groups.3. The tension values from single experimental muscles fell on two independent curves, one for those obtained at L(o), another for data at L. The same muscle showed, therefore, two different fatigue processes which followed independent temporal evolutions.4. Points 2 and 3 of this Summary imply that fatigue is a process dependent on the actual setting of the myofilaments during contraction and not distributed uniformly within the sarcomere.5. It is proposed that fatigue results from local changes taking place at discrete reactive points in the myofilament. The experimental results are discussed in terms of this hypothesis and of the sliding model of contraction. PMID:5723511

Aljure, E F; Borrero, L M

1968-12-01

264

Evidence for the introduction of lethal Chytridiomycosis affecting wild betic midwife toads (Alytes dickhilleni).  

Science.gov (United States)

Batrachochytrium dendrobatidis is an unpredictable pathogen for European amphibian species, and existing field surveillance studies likely underestimate the scope of its distribution and effects. Mass mortality episodes recorded in Europe indicate that investigations of unstudied species should focus on members of the frog family Alytidae. Here, we report the combined results of a field survey and laboratory observations of field collected Alytes dickhilleni. Our data support the hypothesis that B. dendrobatidis has recently emerged in at least two disjunct locations in the species range and populations across much of the species range lack evidence of infection pathogen. Tadpoles taken into the laboratory from sites with infection experienced 70% mortality, unlike those taken into the laboratory from uninfected sites, and both infection and strength of infection was associated with mortality in animals collected from infected locations. Several conservation interventions are underway in response to our study, including the establishment of a captive assurance colony, a public awareness campaign, and experimental tests of disease mitigation schemes. PMID:23494771

Bosch, Jaime; García-Alonso, David; Fernández-Beaskoetxea, Saioa; Fisher, Matthew C; Garner, Trenton W J

2013-03-01

265

Elevated temperature clears chytrid fungus infections from tadpoles of the midwife toad, Alytes obstetricans  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) is sensitive to high temperature. Hence, exposing amphibians to high temperature may be a method to clear Bd infection. However, the effect of exposure to elevated

Geiger, C. C.; Ku?pfer, E.; Scha?r, S.; Wolf, S.; Schmidt, B. R.

2011-01-01

266

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

267

Genotypic analysis of Mucor from the platypus in Australia.  

Science.gov (United States)

Mucor amphibiorum is the only pathogen known to cause significant morbidity and mortality in the free-living platypus (Ornithorhynchus anatinus) in Tasmania. Infection has also been reported in free-ranging cane toads (Bufo marinus) and green tree frogs (Litoria caerulea) from mainland Australia but has not been confirmed in platypuses from the mainland. To date, there has been little genotyping specifically conducted on M. amphibiorum. A collection of 21 Mucor isolates representing isolates from the platypus, frogs and toads, and environmental samples were obtained for genotypic analysis. Internal transcribed spacer (ITS) region sequencing and GenBank comparison confirmed the identity of most of the isolates. Representative isolates from infected platypuses formed a clade containing the reference isolates of M. amphibiorum from the Centraal Bureau voor Schimmelcultures repository. The M. amphibiorum isolates showed a close sequence identity with Mucor indicus and consisted of two haplotypes, differentiated by single nucleotide polymorphisms within the ITS1 and ITS2 regions. With the exception of isolate 96-4049, all isolates from platypuses were in one haplotype. Multilocus fingerprinting via the use of intersimple sequence repeats polymerase chain reaction identified 19 genotypes. Two major clusters were evident: 1) M. amphibiorum and Mucor racemosus; and 2) Mucor circinelloides, Mucor ramosissimus, and Mucor fragilis. Seven M. amphibiorum isolates from platypuses were present in two subclusters, with isolate 96-4053 appearing genetically distinct from all other isolates. Isolates classified as M. circinelloides by sequence analysis formed a separate subcluster, distinct from other Mucor spp. The combination of sequencing and multilocus fingerprinting has the potential to provide the tools for rapid identification of M. amphibiorum. Data presented on the diversity of the pathogen and further work in linking genetic diversity to functional diversity will provide critical information for its management in Tasmanian river systems. PMID:20090018

Connolly, J H; Stodart, B J; Ash, G J

2010-01-01

268

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

269

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

270

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

271

Notes on the Vertebrates of northern Pará, Brazil: a forgotten part of the Guianan Region, I. Herpetofauna  

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Full Text Available We discuss the herpetological results of seven expeditions to the Guianan part of Pará, which resulted in a total of 80 species of amphibians (77 frogs and three caecilians and 95 species of reptiles (36 species of lizards, three species of amphisbaenians, 49 species of snakes, five species of chelonians and two species of caiman. We report six species new to science (three frogs, one caecilian, one lizard, one amphisbaenian, six new records for Brazil (five frogs, one caecilian and 23 new records for Pará (13 frogs, four lizards, six snakes. For each of the new records we provide comments. Special comment is made about a large population of the toad Atelopus hoogmoedi that seems to be doing well and does not show any signs of population decline as many species of Atelopus at higher elevations do. We provide a complete list of species collected per locality containing data on endemicity, habitat, reproduction and food. For each of the seven collecting sites we provide data on richness and abundance of species. The sites are compared regarding their speciescomposition, even though we can not say how much of the differences are due to specific habitats or geographic variation, seasonal variation or sampling deficiency. We synonymised the Bufonid Rhinella martyi with Bufo margaritifer and selected a lectotype for Rana margaritifera in order to resolve the problems about this name.

Teresa Cristina Sauer Avila-Pires

2010-04-01

272

Acute toxicity of zinc to several aquatic species native to the Rocky Mountains.  

Science.gov (United States)

National water-quality criteria for the protection of aquatic life are based on toxicity tests, often using organisms that are easy to culture in the laboratory. Species native to the Rocky Mountains are poorly represented in data sets used to derive national water-quality criteria. To provide additional data on the toxicity of zinc, several laboratory acute-toxicity tests were conducted with a diverse assortment of fish, benthic invertebrates, and an amphibian native to the Rocky Mountains. Tests with fish were conducted using three subspecies of cutthroat trout (Colorado River cutthroat trout Oncorhynchus clarkii pleuriticus, greenback cutthroat trout O. clarkii stomias, and Rio Grande cutthroat trout O. clarkii virginalis), mountain whitefish (Prosopium williamsoni), mottled sculpin (Cottus bairdi), longnose dace (Rhinichthys cataractae), and flathead chub (Platygobio gracilis). Aquatic invertebrate tests were conducted with mayflies (Baetis tricaudatus, Drunella doddsi, Cinygmula sp. and Ephemerella sp.), a stonefly (Chloroperlidae), and a caddis fly (Lepidostoma sp.). The amphibian test was conducted with tadpoles of the boreal toad (Bufo boreas). Median lethal concentrations (LC(50)s) ranged more than three orders of magnitude from 166 ?g/L for Rio Grande cutthroat trout to >67,000 ?g/L for several benthic invertebrates. Of the organisms tested, vertebrates were the most sensitive, and benthic invertebrates were the most tolerant. PMID:21811884

Brinkman, Stephen F; Johnston, Walter D

2012-02-01

273

Mercury-resistant plasmids in bacteria from a mercury and antimony deposit area.  

Science.gov (United States)

Most bacterial cells (Pseudomonas, Acinetobacter) obtained from the soil at the Khaidarkan mercury and antimony mine (Kirghiz USSR) contain R plasmids with mercury (HgCl2) resistance determinants. The plasmids have a large molecular mass (about 100 MD, though smaller ones also occur), and at least some of them are transmissive. Many of the Hgr bacteria also display an elevated antimony (SbCl3) resistance, though this trait was not shown to be plasmid-dependent. There are practically no Hgr plasmids in bacteria taken from the soil at different distances from the mine: the saturation of bacteria with Hgr plasmids is maintained by selective pressure only in the area with a high enough toxin concentration. In the same mercury and antimony deposit area Hgr plasmids were also found in Escherichia coli isolates from the gut of Mus musculus mice and Bufo viridis toads. At least some of the bacterial plasmids obtained from animals also carry antibiotic-resistance determinants (Tcr, Cmr, Smr). These plasmids are also transmissive. They display internal instability and lose their resistance determinants after a conjugation transfer to other E. coli strains. PMID:6394954

Khesin, R B; Karasyova, E V

1984-01-01

274

[R-factors of mercury resistance in bacteria isolated in the mercury-antimony deposit region].  

Science.gov (United States)

Most of bacterial cells in soil samples taken from a mine at the Khaidarkan mercury-antimony deposit (Kirghiz SSR) proved to contain R-plasmids with determinants of mercury resistance (HgCl2). Plasmids had a high molecular mass (approximately 10(8], though some deviated substantially from this size; at least part of them were transmissible. Many Hgr bacteria also showed an increased resistance to antimony (SbCl3), but no relation could be found between this character and the plasmids. Bacteria from soil samples taken at different distances from the mine were virtually devoid of Hgr plasmids: saturation of bacteria with Hgr factors is maintained by selective pressure action only within regions with high concentration of poison. Hgr plasmids at the Khaidarkan deposit were also found in enteric bacteria isolates from the gut of Mus musculus mice and Bufo viridis toads. Some bacterial plasmids from animals carried, apart from Hgr, antibiotic resistance determinants (Tcr, Cmr, Smr), i.e. were multiple resistance factors. These plasmids often displayed intrinsic instability and lost resistance determinants when conjugationally transferred to some E. coli strains. PMID:3158803

Khesin, R B

1985-01-01

275

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

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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

276

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

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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. heterod...

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

2011-01-01

277

Distribution and characteristics of aquatic habitats of newts and yellow-bellied toads in the district of Ioannina (Epirus, Greece)  

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The study describes the aquatic habitats and distribution of Triturus alpestris veluchiensis Wolterstorff 1935, T. carnifex macedonicus (Karaman, 1922), T. vulgaris graecus (Wolterstorff, 1905) and Bombina variegata scabra (Küster, 1843) in the district (“nomos”) of Ioannina, Northern Greece. Bombina variegata was found to be the most common species, followed by T. alpestris and T. carnifex while T. vulgaris seemed to be rare. The four taxa differed in habitat use and geographic distribu...

2004-01-01

278

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.

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

279

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

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A mathematical model of an absorbing leaky epithelium is developed for analysis of solute coupled water transport. The non-charged driving solute diffuses into cells and is pumped from cells into the lateral intercellular space (lis). All membranes contain water channels with the solute passing those of tight junction and interspace basement membrane by convection-diffusion. With solute permeability of paracellular pathway large relative to paracellular water flow, the paracellular flux ratio...

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

2000-01-01

280

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.

2010-10-01

 
 
 
 
281

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

282

Evaluating Amphibian Declines with Site Revisits and Occupancy Models: Status of Montane Anurans in the Pacific Northwest USA  

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Full Text Available Amphibian declines have been reported in mountainous areas around the western USA. Few data quantify the extent of population losses in the Pacific Northwest, a region in which amphibian declines have received much attention. From 2001–2004, we resurveyed historical breeding sites of two species of conservation concern, the Western Toad (Bufo [=Anaxyrus] boreas and Cascades Frog (Rana cascadae. We detected B. boreas breeding at 75.9% and R. cascadae breeding at 66.6% of historical sites. When we analyzed the data using occupancy models that accounted for detection probability, we estimated the current use of historically occupied sites in our study area was 84.9% (SE = 4.9 for B. boreas and 72.4% (SE = 6.6 for R. cascadae. Our ability to detect B. boreas at sites where they were present was lower in the first year of surveys (a low snowpack year and higher at sites with introduced fish. Our ability to detect R. cascadae was lower at sites with fish. The probability that B. boreas still uses a historical site for breeding was related to the easting of the site (+ and the age of record (-. None of the variables we analyzed was strongly related to R. cascadae occupancy. Both species had increased odds of occupancy with higher latitude, but model support for this variable was modest. Our analysis suggests that while local losses are possible, these two amphibians have not experienced recent, broad population losses in the Oregon Cascades. Historical site revisitation studies such as ours cannot distinguish between population losses and site switching, and do not account for colonization of new habitats, so our analysis may overestimate declines in occupancy within our study area.

Brome McCreary

2009-12-01

283

Changes in the mechanical properties of human and amphibian muscle after eccentric exercise.  

Science.gov (United States)

Following a series of eccentric contractions, that is stretching of the muscle while generating active tension, the length-tension relationship of isolated amphibian muscle has been shown to shift towards longer muscle length (Katz 1939; Wood et al. 1993). Here we report observations of electrically stimulated ankle extensor muscles of nine human subjects, demonstrating a similar shift in optimum angle for torque generation [3.9 (1.5) degrees] following exercise on an inclined treadmill that involved eccentric contractions in one leg. (All values are means with the SEMs in parentheses). The shift in the unexercised, control leg was significantly less [mean 0.4 (0.7) degree P < 0.05]. Correlated with this shift was a drop in torque [25.1 (5.6)% for the experimental leg; 1.6 (0.7)% for the control leg, P < 0.002]. Optimum angles returned to pre-exercise values by 2 days post-exercise, while torque took a week to recover. A similar shift in optimum length [12 (1.3)% of rest length] was obtained for five toad (Bufo marinus) sartorius muscles subjected to 25 eccentric contractions. Isometrically contracted control muscles showed a smaller shift [3.5 (1.6)%, n = 5]. Accompanying the shift was a drop in tension of 46 (3)% after the eccentric contractions [control isometric, 23 (6)%, P < 0.0001]. By 5 h after the eccentric contractions the shift had returned to control values, while tension had not recovered. When viewed with an electron microscope, sartorius muscles fixed immediately after the eccentric contractions exhibited many small, and a few larger, regions of myofilament disruption. In muscles fixed 5 h after the contractions, no small regions of disruption were visible, and the number of large regions was no greater than in those muscles fixed immediately after the eccentric contractions. These disruptions are interpreted as the cause of the shift in length-tension relationship. PMID:9243166

Jones, C; Allen, T; Talbot, J; Morgan, D L; Proske, U

1997-01-01

284

Phytochemical Investigation of Biologically Active Fractions of Astragalus spinosus Roots Grown in Egypt  

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Full Text Available The research work was undertaken to asses activity directed isolation of plant extracts, column fractions and isolated glycosides of Astragalus spinosus roots (Fabaceae in the treatment of induced hepatic, renal and cardiac toxicities. A single subcutaneous dose of CCl4 (5.93 ml kg-1 b.wt. which represents 24h LD100 served as a toxicant, was used during this study. Ethyl acetate fraction was the most active fraction, then butanol, aqueous and dichloromethane fraction. By subjecting the ethyl acetate fraction to column chromatography (CC it afforded two column fractions A and B which have effect in reducing CCl4-induced mortalities. Rechromatography of fractions A and B on medium pressure liquid chromatography (MPLC and CC, respectively, afforded (a mixture of isoastragaloside I and trigonoside I and cycloastragenol-6-0-glucoside. The structure of the isolated glycosides was determined by 1H, 13C NMR, EIMS and FABMS spectral data, together with co-TLC with reference materials. The efficacy of the isolated glycosides (isoastragaloside I and trigonoside I, cycloastragenol-6-0-glycoside and adsurgenic acid (recently isolated from the ether extract in reducing CCl4-induced mortalities and some disturbances in biochemical parameters (liver transaminases AST, ALT and creatine kinase CK activities, serum urea and serum creatinine were investigated in adult female Bufo regularis (Egyptian toads. The bioassay studies revealed that the effect of the glycosides on reducing CCl4-induced mortality have the following order (cycloastragenol-6-0-glycoside > isoastragaloside I and trigonoside I > adsurgenic acid. The biochemical studies confirmed the bioassay studies. This is the first report on the identification of trigonoside I in Astragalus spinosus plant and the presence of isoastragaloside I and cylcoastragenol-6-0-glycoside in A. spinosus roots. This suggested that these saponin glycosides may be promising in modulating CCl4-induced lethality and most of its toxic effects.

Fikria A. Darwish

2002-01-01

285

Pseudacris triseriata (western chorus frog) and Rana sylvatica (wood frog) chytridiomycosis  

Science.gov (United States)

The chytrid fungus Batrachochytrium dendrobatidis is a known pathogen of anuran amphibians, and has been correlated with amphibian die-offs worldwide (Daszak et. al. 1999. Emerging Infectious Diseases 5:735-748). In Colorado, B. dendrobatidis has infected Boreal toads (Bufo boreas) (Muths et. al., in review) and has been identified on museum specimens of northern leopard frogs (Rana pipiens) (Carey et. al. 1999. Develop. Comp. Immunol. 23:459-472). We report the first verified case of chytrid fungus in chorus frogs (Pseudacris triseriata) and wood frogs (Rana sylvatica) in the United States. We collected seven P. triseriata, and two adult and two juvenile R. sylvatica in the Kawuneeche Valley in Rocky Mountain National Park (RMNP) during June 2001. These animals were submitted to the National Wildlife Health Center (NWHC) as part of an amphibian health evaluation in RMNP. Chorus frogs were shipped in one container. Wood frog adults and juveniles were shipped in two separate containers. Histological examinations of all chorus frogs and 3 of 4 wood frogs were positive for chytrid fungus infection. The fourth (adult) wood frog was too decomposed for meaningful histology. Histological findings consisted of multifocally mild to diffusely severe infections of the epidermis of the ventrum and hindlimb digital skin. Chytrid thalli were confined to the thickened epidermis (hyperkeratosis), were spherical to oval, and occasional thalli contained characteristic discharge pores or zoospores (Green and Kagarise Sherman 1999. J. Herpetol 35:92-103; Fellers et al. 2001. Copeia 2001:945-953). We cannot confirm that all specimens carried the fungus at collection, because infection may have spread from one individual to all other individuals in each container during transport. Further sampling of amphibians in Kawuneeche Valley is warranted to determine the rate of infection and mortality in these populations.

Rittman, S. E.; Muths, E.; Green, D. E.

2003-01-01

286

Guidance for possession, transport, sale and exchange of Annexe IV ...  

Sep 2, 2007 ... injured and could not fly away the defence could be relied upon for their removal \\for tending and release. ..... Midwife Toad; Olive Midwife Toad. Anaecypris \\hispanica .... Egyptian Fruit Bat; Egyptian Rousette. Rupicapra ...

287

From Antarctica or Asia? New colonization scenario for Australian-New Guinean narrow mouth toads suggested from the findings on a mysterious genus Gastrophrynoides  

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Full Text Available Abstract Background Microhylidae is a geographically widespread family of anurans. Although several extensive molecular analyses have attempted to elucidate their subfamilial relationships, and correlate these with Mesozoic and Cenozoic continental drifts, consensus has not been reached. Further, generic level relationships have not been well investigated in some microhylid subfamilies, and therefore subfamilial affiliations of some genera are still unclear. To elucidate the phylogenetic positions of two mysterious Asian genera, Gastrophrynoides and Phrynella, and to better understand the trans-continental distributions of microhylid taxa, we performed molecular phylogenetic and dating analyses using the largest molecular dataset applied to these taxa to date. Results Six nuclear and two mitochondrial genes (approx. 8 kbp were sequenced from 22 microhylid frog species representing eight subfamilies. The maximum likelihood and Bayesian analyses could not fully elucidate the subfamilial relationships, suggesting a rapid radiation of these taxa between 85 and 66 million years ago. In contrast, generic relationships of Asian microhylines were generally well resolved. Conclusion Our results clearly showed that one of two problematic Asian genera, Phrynella, was nested in the clade of the Asian subfamily Microhylinae. By contrast, Gastrophrynoides occupied the most basal position of the Australian-New Guinean subfamily Asterophryinae. The estimated divergence of Gastrophrynoides from other asterophryine was unexpectedly around 48 million years ago. Although a colonization scenario via Antarctica to the Australian-New Guinean landmass has been suggested for Asterophryinae, our finding suggested a novel colonization route via Indo-Eurasia.

Ahmad Norhayati

2011-06-01

288

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

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There is evidence that environmental metal levels affect the immune function. In the particular case of the impact of heavy metals, information available suggests that the immune system is a target for low-dose Pb exposure. Among vertebrates it was shown that amphibians are capable of forming antibodies against a variety of antigens, causing several responses such as anaphylactic response and rejecting grafts. In this study, the production of antibodies was assessed against sheep red blood ce...

Rosenberg, Carolina E.; Fink, Nilda E.; Alfredo Salibián

2007-01-01

289

Risk from radionuclides: a frog's perspective : Accumulation of 137Cs in a riparian wetland, radiation doses, and effects on frogs and toads after low-dose rate exposure  

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Threats from man-made radionuclides include waste issues, increasing number of power plants, underground bomb testing, nuclear weapons, and “dirty bombs”. Until recently the ionizing radiation protection system focused on protecting humans with an implied protection of biota. However, goals of sustainable development and precautionary principles for human activity are leading to an inclusion of plant and animal populations in the protection system. From this perspective, the present thesi...

2006-01-01

290

Reptile and amphibian responses to large-scale wildfires in southern California  

Science.gov (United States)

In 2003, southern California experienced several large fires that burned thousands of hectares of wildlife habitats and conserved lands. To investigate the effects of these fires on the reptile and amphibian communities, we compared the results from prefire herpetofauna and vegetation sampling to two years of postfire sampling across 38 burned and 17 unburned plots. The sampling plots were spread over four vegetation types and four open space areas within San Diego County. Our capture results indicated that burned chaparral and coastal sage scrub plots lost herpetofaunal species diversity after the fires and displayed a significant shift in overall community structure. Shrub and tree cover at the burned plots, averaged across the second and third postfire years, had decreased by 53 in chaparral and 75 in coastal sage scrub. Additionally, postfire herpetofauna community structure at burned plots was more similar to that found in unburned grasslands. In grassland and woodland/riparian vegetation plots, where shrub and tree cover was not significantly affected by fires, we found no differences in the herpetofaunal species diversity or community composition. At the individual species level, Sceloporus occidentalis was the most abundant reptile in these areas both before and after the fires. We saw increases in the net capture rates for several lizard species, including Aspidoscelis tigris, Phrynosoma coronatum, and Uta stansburiana in burned chaparral plots and Aspidoscelis hyperythra and U. stansburiana in burned coastal sage scrub plots. The toad, Bufo boreas, was detected at significantly fewer burned plots in chaparral after the fires. Additionally, we documented decreases in the number of plots occupied by lizards (Elgaria multicarinata), salamanders (Batrachoseps major), and snakes (Coluber constrictor, Lampropeltis getula, Pituophis catenifer, and Masticophis lateralis) in coastal sage scrub and chaparral after the fires. We discuss the individual species results as they relate to such life-history traits as the susceptibility to initial mortality, the response to the altered postfire habitat, and shifts in the availability of potential prey. We foresee that a continued unnatural fire regime will result in a simplification of the southern California reptile and amphibian communities. ?? 2010 Society for the Study of Amphibians and Reptiles.

Rochester, C. J.; Brehme, C. S.; Clark, D. R.; Stokes, D. C.; Hathaway, S. A.; Fisher, R. N.

2010-01-01

291

Annual Proxy Records from Tropical Cloud Forest Trees in the Monteverde Cloud Forest, Costa Rica  

Science.gov (United States)

The extinction of the Golden Toad (Bufo periglenes) from Costa Rica's Monteverde Cloud Forest prompted research into the causes of ecological change in the montane forests of Costa Rica. Subsequent analysis of meteorological data has suggested that warmer global surface and tropical Pacific sea surface temperatures contribute to an observed decrease in cloud cover at Monteverde. However, while recent studies may have concluded that climate change is already having an effect on cloud forest environments in Costa Rica, without the context provided by long-term climate records, it is difficult to confidently conclude that the observed ecological changes are the result of anthropogenic climate forcing, land clearance in the lowland rainforest, or natural variability in tropical climate. To address this, we develop high-resolution proxy paleoclimate records from trees without annual rings in the Monteverde Cloud Forest in Costa Rica. Calibration of an age model in these trees is a fundamental prerequisite for proxy paleoclimate reconstructions. Our approach exploits the isotopic seasonality in the ?18O of water sources (fog versus rainfall) used by trees over the course of a single year. Ocotea tenera individuals of known age and measured annual growth increments were sampled in long-term monitored plantation sites in order to test this proposed age model. High-resolution (200?m increments) stable isotope measurements on cellulose reveal distinct, coherent ?18O cycles of 6 to 10‰. The calculated growth rates derived from the isotope timeseries match those observed from basal growth increment measurements. Spatial fidelity in the age model and climate signal is examined by using multiple cores from multiple trees and multiple sites. These data support our hypothesis that annual isotope cycles in these trees can be used to provide chronological control in the absence of rings. The ability of trees to record interannual climate variability in local hydrometeorology and remote climate forcing is evaluated using the isotope signal from multiple trees, local meteorological observations, and climate field data for the well-observed 1997-1998 warm El Niño-Southern Oscillation (ENSO) event. The successful calibration of our age model is a necessary step toward the development of long, annually-resolved paleoclimate reconstructions from old trees, even without rings, which will be used to evaluate the cause of recent observed climate change at Monteverde and as proxies for tropical climate field reconstructions.

Anchukaitis, K. J.; Evans, M. N.; Wheelwright, N. T.; Schrag, D. P.

2005-12-01

292

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

293

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

294

Moriyama tubamajad väikesele pinnale  

Index Scriptorium Estoniae

Jaapani arhitektid on lahendanud probleemi, kuidas võimalikult väikesele pinnale mahutada tavalise pere elamine. Kõik toad on eraldiseisvate aiamajakestena paigutatud väiksele krundile kõrvuti, üksteise peale ja vahele

2008-01-01

295

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

296

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

297

76 FR 35235 - Endangered and Threatened Species Permit Applications  

Science.gov (United States)

...Bufo houstonensis), and black-footed ferret (Mustela nigripes) within the Fort Worth Zoo. Permit TE-43719A Applicant...sucker (Xyrauchen texanus), black-footed ferret (Mustela nigripes), Arizona cliffrose (Purshia subintegra), and Gila...

2011-06-16

298

Primer registro de especies del suborden myxophaga (insecta: coleoptera en la provincia del Golfo de Mexico  

Directory of Open Access Journals (Sweden)

Full Text Available Members of the Coleoptera suborder Myxophaga: Lepicerus bufo Hinton (Lepiceridae and Sphaerius sp. (Sphaeriusidae are recorded by the first time for the lowlands of Gulf of Mexico in southern Veracruz, Mexico.

Miguel Ángel Morón

2008-01-01

299

Facile synthesis of two diastereomeric indolizidines corresponding to the postulated structure of alkaloid 5,9E-259B from a Bufonid toad (Melanophryniscus)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 differe...

Nelson Angela; Martin, Garraffo H.; Spande Thomas F; Daly John W; Stevenson Paul J

2008-01-01

300

Notice on the ocurrence of supernumerary teeth in the two-toad sloths Choloepus didactylus and C. hoffmanni / Noticias sobre la ocurrencia de dientes supernumerarios en perezosos de dos dedos, Choloepus didactylus y C. hoffmanni  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in spanish Si bien casi todos los órdenes de mamíferos modernos presentan dientes supernumerarios, no se habían publicado casos entre pilosos vivientes. En este estudio se documentan dientes supernumerarios en tres individuos del género de perezosos Choloepus: dos C. hoffmani y un C. didactylus. Todos los dien [...] tes duplicados se encuentran en el maxilar derecho. Uno de los dos C. hoffmani presenta, además, un diente duplicado del lado izquierdo, lo que sugiere que la duplicación no es específica a nivel de taxón o lateralidad. Los dientes de los perezosos erupcionan como conos simples redondeados y, por lo tanto, la variedad de patrones cuspidales característicos de cada género se produce por el desgaste y el desplazamiento en el espacio de las denticiones superior e inferior. Abstract in english Supernumerary teeth occur in nearly all modern mammalian orders, although no previous cases have been published for extant pilosans. We report here three specimens of the sloth genus Choloepus, two C. hoffmanni and one C. didactylus, exhibiting supernumerary teeth. All duplicated teeth are maxillary [...] , and all but one on the right side. One C. hoffmanni bears an additional left tooth, suggesting duplication is neither species nor toothrow-side specific. Sloth teeth erupt as simple rounded cones and the different "cusp" patterns characteristic of each extant and extinct genus arise from wear and the differential spacing of upper versus lower dentitions.

Robert K, McAfee; Virginia L, Naples.

 
 
 
 
301

Amphibians of the Ausoni Mountains (Latium, Central Italy  

Directory of Open Access Journals (Sweden)

Full Text Available In this study we searched for amphibians in 89 potential breeding sites within the Ausoni Mounts, which are among the less investigated areas of Latium. Sixtynine spawning sites, and eight amphibian species (57.1% of the 14 amphibian species living in Latium region were found. Reproductive activity was recorded for Salamandrina perspicillata, Triturus carnifex, Lissotriton vulgaris, Lissotriton italicus, Bufo bufo, Hyla intermedia, Rana italica and Pelophylax synklepton hispanica.

Antonio Romano

2007-11-01

302

Morphological distinction between filaments that converge upon desmosomes and those that are attached to hemidesmosomes in the epidermis of anuran larvae and lampreys.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two populations of morphologically distinct intermediate filaments which are segregated into different compartments of the cytoplasm and which may attach to different junctional specialisations were observed in the basal layer cells of the epidermis of tadpoles of Rana catesbeiana, Rana temporaria, Bufo bufo, Leptodactylus flavopictus and Pseudis paradoxus and in the skin of the adult lamprey, Lampetra planeri. These two distinct populations of cytokeratin intermediate filaments were recognis...

1991-01-01

303

Behavioural flexibility allows an invasive vertebrate to survive in a semi-arid environment.  

Science.gov (United States)

Plasticity or evolution in behavioural responses are key attributes of successful animal invasions. In northern Australia, the invasive cane toad (Rhinella marina) recently invaded semi-arid regions. Here, cane toads endure repeated daily bouts of severe desiccation and thermal stress during the long dry season (April-October). We investigated whether cane toads have shifted their ancestral nocturnal rehydration behaviour to one that exploits water resources during the day. Such a shift in hydration behaviour could increase the fitness of individual toads by reducing exposure to desiccation and thermal stress suffered during the day even within terrestrial shelters. We used a novel method (acoustic tags) to monitor the daily hydration behaviour of 20 toads at two artificial reservoirs on Camfield station, Northern Territory. Remarkably, cane toads visited reservoirs to rehydrate during daylight hours, with peaks in activity between 9.00 and 17.00. This diurnal pattern of rehydration activity contrasts with nocturnal rehydration behaviour exhibited by adult toads in their native geographical range and more mesic parts of Australia. Our results demonstrate that cane toads phase shift a key behaviour to survive in a harsh semi-arid landscape. Behavioural phase shifts have rarely been reported in invasive species but could facilitate ongoing invasion success. PMID:24573152

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

2014-02-01

304

Release calls of female Bombina bombina (Anura: Bombinatoridae)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Release calls of a female fire-bellied toad, Bombina bombina, were recorded in the field while handling the toad. Duration and structure of these calls are similar to release calls of male B. bombina.

Günter Gollmann; Andreas Benkö; Walter Hödl

2009-01-01

305

Ahju tuleb kütta kuivade puude ja kõva tulega / Arvo Uustalu  

Index Scriptorium Estoniae

Vt. ka Linnaleht : Pärnu ; Linnaleht : Tartu 10. veebr., lk. B3. Tartus tegutseva ahjupotivabriku omanik ja ahjumeister Annes Andersson annab nõu, kuidas ja millega kütta, et toad oleksid mõnusalt soojad

Uustalu, Arvo, 1964-

2006-01-01

306

Otsitakse pilte Kalvi mõisast  

Index Scriptorium Estoniae

OÜ Kalwi Mõis otsib fotosid, maale, kirjeldusi ja mälestusi Kalvi mõisast ja selle ümbrusest, et neid kasutada mõisa restaureerimiseks ja mõisa ajalugu tutvustava muuseumitoa sisustamiseks; mõisa kavatsetakse rajada hotell, mille toad sisustataks ajaloolistes stiilides.

2000-01-01

307

Hilissügise õhtul : [luuletused] / Ain Väät  

Index Scriptorium Estoniae

Sisu: Hilissügise õhtul ; Kalalkäik ; Koerailm ; Tasakaal ; Hiirte elu ; Vabaõhukontsert ; Õhtu varestega ; Heliredel ; Noorte kukkede koor ; Lindude kaitseks ; Valge hommik ; Kala mäng ; Siili vatitekk ; Taevane lugu ; Toad on vahel segamini ; Õhtu tuleb ; Õhtul ; Juss sööb õuna ; Sirtsud ; Tõnu jõulusalm

Väät, Ain

2001-01-01

308

Presidendi külalismaja avatakse turistidele märtsis / Kadri Paas  

Index Scriptorium Estoniae

President Toomas Hendrik Ilvese ja proua Evelin Ilvese Ärma talu- ja puhkekompleks Erma Park Abja-Paluoja naabruses avatakse külalistele 2007. a. märtsis. Külaliste toad kannavad tuntud ajalooliste ühiskonna- ja kultuuritegelaste nimesid

Paas, Kadri, 1982-

2007-01-01

309

Amphibians of the Simbruini Mountains (Latium, Central Italy  

Directory of Open Access Journals (Sweden)

Full Text Available Little attention has been paid to the herpetological fauna of the Simbruini Mountains Regional Park, Latium (Central Italy. In this study, we surveyed 50 sites in the course of about ten years of field research, especially during the period 2005-2008. Nine amphibian species, four Caudata and five Anura, 60.0% out of the 15 amphibian species so far observed in Latium, were discovered in the protected area: Salamandra salamandra, Salamandrina perspicillata, Lissotriton vulgaris, Triturus carnifex, Bombina pachypus, Bufo balearicus, Bufo bufo, Rana dalmatina, Rana italica. Physiography of sites has been detailed together with potential threatening patterns. For each species the following topics have been discussed; ecology of sites, altitudinal distribution, phenology, sintopy. Salamandra salamandra and Bombina pachypus are at higher risk. The importance of the maintenance of artificial/natural water bodies for the conservation management of amphibian population of this territory is discussed.

Luca Tringali

2010-07-01

310

Surviving Chytridiomycosis: Differential Anti-Batrachochytrium dendrobatidis Activity in Bacterial Isolates from Three Lowland Species of Atelopus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the Neotropics, almost every species of the stream-dwelling harlequin toads (genus Atelopus) have experienced catastrophic declines. The persistence of lowland species of Atelopus could be explained by the lower growth rate of Batrachochytrium dendrobatidis (Bd) at temperatures above 25°C. We tested the complementary hypothesis that the toads' skin bacterial microbiota acts as a protective barrier against the pathogen, perhaps delaying or impeding the symptomatic phase of chytridiomycosis...

Flechas, Sandra V.; Sarmiento, Carolina; Ca?rdenas, Martha E.; Medina, Edgar M.; Restrepo, Silvia; Ame?zquita, Adolfo

2012-01-01

311

[Toxicity of drugs on nasal mucocilia and the method of its evaluation].  

Science.gov (United States)

Effect of solutions or suspensions of eight drugs including analgin, paracetamol, propafenone hydrochloride, propranolol hydrochloride, ephedrine hydrochloride, gentamycin sulfate, sodium deoxycholate and hydrocortisone on ciliary movement were evaluated with in vitro or in situ toad palate model and scanning electron microscope. In vitro toad palate model: 0.2 ml of test drug solution or suspension was applied to a piece of freshly dissected upper palate of toad. The mucocilia were examined with an optical microscope and the lasting time of ciliary movement was recorded after drug application. The upper palate was rinsed with physiological saline when the ciliary movement stopped. The lasting time of ciliary movement after rinsing was then recorded again. In situ palate model: 0.5 ml of test drug solution or suspension was applied to the upper palate of toad for 30 min, and rinsed with physiological saline. The palate was dissected out and the operation was carried out in a similar manner. The results showed that the in situ toad palate model is a satisfactory method for studying the ciliotoxicity of drugs. The in vitro toad palate model is unsuitable for suspension and gel. The results of the eight drugs revealed that ciliary movement is frequently affected by many drugs and, therefore, care must be taken in developing any nasal dosage form to ensure its least ciliotoxicity. PMID:8712011

Jiang, X G; Cui, J B; Fang, X L; Wei, Y; Xi, N Z

1995-11-01

312

Revisão do gênero Satipoella (Coleoptera, Cerambycidae, Lamiinae Revision of the genus Satipoella (Coleoptera, Cerambycidae, Lamiinae  

Directory of Open Access Journals (Sweden)

Full Text Available The genus Satipoella Lane, 1964 is revised and a new synonym is proposed, Icarai Galileo & Martins, 1998, with Satipoella. A new species, S. ochroma, is described from Amazonas, Brazil. New combination: Satipoella bufo (Thomson, 1864 from Icarai. The three species of Satipoella are illustrated and keyed.

Carlos Eduardo de Alvarenga Julio

2003-06-01

313

Revisão do gênero Satipoella (Coleoptera, Cerambycidae, Lamiinae) / Revision of the genus Satipoella (Coleoptera, Cerambycidae, Lamiinae)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese [...] Abstract in english The genus Satipoella Lane, 1964 is revised and a new synonym is proposed, Icarai Galileo & Martins, 1998, with Satipoella. A new species, S. ochroma, is described from Amazonas, Brazil. New combination: Satipoella bufo (Thomson, 1864) from Icarai. The three species of Satipoella are illustrated and [...] keyed.

Carlos Eduardo de Alvarenga, Julio.

314

A hybrid zone of two toad sister species, Rhinella atacamensis and R. arunco (Anura: Bufonidae), defined by a consistent altitudinal segregation in watersheds / Una zona de hibridación de dos especies hermanas de anuros, Rhinella atacamensis y R. arunco (Anura: Bufonidae), definida por una consistente segregación altitudinal en cuencas hidrográficas  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Definir la extensión espacial de una zona de hibridación es esencial para entender su origen histórico e identificar los factores geográficos y/o ambientales que la delimitan. Rhinella atacamensis y R. arunco son dos especies hermanas que en conjunto habitan entre los 25 y 38° S a lo largo de Chile. [...] Sus límites de distribución coinciden aproximadamente a los 32° S, donde recientemente se reportó que hibridan en una pequeña cuenca hidrográfica (estero Pupío). Aunque la evidencia genética sugiere que estas especies forman un enjambre híbrido, no se mezclan homogéneamente a lo largo de la cuenca sino que se segregan espacialmente: R. arunco se encuentra en la parte baja del estero, mientras que R. atacamensis se ubica en la parte alta. Una extensa exploración al norte y sur de los 32° S reveló otras instancias de hibridación donde se mantiene el mismo patrón de segregación espacial dentro de otras cuencas. En este estudio se describe esta zona de hibridación combinando secuencias mitocondriales y marcadores nucleares AFLP. En su parte norte, la zona conforma una estrecha franja que atraviesa varias cuencas extendiéndose más de 130 km en dirección noroeste-sureste, de manera que R. atacamensis se encuentra cada vez a mayor altura a medida que se avanza hacia el sur. Sin embargo, dos puntos ubicados el sur de esta franja muestran que la zona de hibridación es más extensa y compleja, y que probablemente se extiende por todo el borde de las cadenas de cerros que conforman la cuenca hidrográfica del río Aconcagua (32°30' - 33° S). Se plantea una explicación para el origen de esta zona de hibridación considerando antecedentes paleoclimáticos y orográficos y se discuten brevemente las implicancias taxonómicas de estos resultados. Abstract in english Delimiting the spatial extension of a hybrid zone is essential to understand its historical origin and to identify the geographical and/or environmental factors which delimit it. Rhinella atacamensis and R. arunco are two sister species which together inhabit Chile between 25° and 38° S. Their distr [...] ibution limits coincide at about 32° S, where recently it was reported that they hybridize in a small watershed (Pupío creek). Although the genetic evidence suggests that these two species form a hybrid swarm, they are not mixed homogeneously in the entire watershed, but rather are spatially segregated: R. arunco is found in the lower part of the creek and R. atacamensis in the higher part. An extensive exploration north and south of 32° S revealed other instances of hybridization, with the same pattern of spatial segregation within other watersheds. This study describes the hybrid zone combining mitochondrial sequences and nuclear AFLP markers. In the northern part, the hybrid zone is a narrow strip which crosses several watersheds and extends more than 130 km from NW-SE, so that R. atacamensis is found at higher altitudes towards the south. However, two points south of this strip show that the hybrid zone is more extensive and complex, and probably extends along the entire border of the mountain chains which form the watershed of the Aconcagua River (32°30' - 33° S). We propose an explanation for the origin of this hybrid zone considering paleoclimatic and orographic information, and briefly discuss the taxonomic implications of these results.

CLAUDIO, CORREA; MARCO A, MÉNDEZ; SERGIO, ARAYA; GABRIEL, LOBOS; R. EDUARDO, PALMA.

315

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

Scientific Electronic Library Online (English)

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

CAROLINA E, GALLARDO; HÉCTOR J, HERNÁNDEZ; JOSÉ A. F, DINIZ-FILHO; R. EDUARDO, PALMA; MARCO A, MÉNDEZ.

316

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

Directory of Open Access Journals (Sweden)

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

CAROLINA E GALLARDO

2011-09-01

317

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

We analyzed the relationship of landscape and environmental features on the genetic differentiation of Rhinella spinulosa (Wiegmann, 1834) in the Altiplano of Antofagasta (Chile). We performed three types of analyses at different spatial scales: (1) Considering all populations; (2) Grouping populations by watershed and by sub-watershed; and (3) Using the results of a spatial analysis of molecular variation (SAMOVA). Landscape features were incorporated using Geographic Information Systems, wi...

2011-01-01

318

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

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents a positioning algorithm, named time of arrival to time difference of arrival (TOAD, which computes time-difference-of-arrival (TDOA measurements from the messages that time-of-arrival (TOA stations in sight exchange while their positioning processes are running. This study addresses the accuracy of the TOAD algorithm in two different environments: line-of-sight (LOS and non-line-of-sight (NLOS. Simulation is used to set up a wireless network. The Gauss-Newton nonlinear least squares algorithm is used to compute the positions in both TOA and TOAD stations. Results indicate that the TOAD algorithm increases the root mean square error (RMSE of the positioning error in LOS scenarios by 10 to 20% compared with the RMSE achieved by TOA. This drop in accuracy contrasts with the results for the NLOS scenarios. The RMSE of TOAD in such scenarios is at least 10% lower than that achieved by TOA. This result is specially important since this latter scenario is the most common. Consequently, this novel technique therefore improves the scalability and integrity of TOA techniques based on RTT, making it possible for the stations to position themselves without injecting traffic and with QoS figures close and most times better than that achieved by TOA.

Francisco Barcelo-Arroyo

2008-03-01

319

Adrenocortical stress responses influence an invasive vertebrate's fitness in an extreme environment.  

Science.gov (United States)

Continued range expansion into physiologically challenging environments requires invasive species to maintain adaptive phenotypic performance. The adrenocortical stress response, governed in part by glucocorticoid hormones, influences physiological and behavioural responses of vertebrates to environmental stressors. However, any adaptive role of this response in invasive populations that are expanding into extreme environments is currently unclear. We experimentally manipulated the adrenocortical stress response of invasive cane toads (Rhinella marina) to investigate its effect on phenotypic performance and fitness at the species' range front in the Tanami Desert, Australia. Here, toads are vulnerable to overheating and dehydration during the annual hot-dry season and display elevated plasma corticosterone levels indicative of severe environmental stress. By comparing unmanipulated control toads with toads whose adrenocortical stress response was manipulated to increase acute physiological stress responsiveness, we found that control toads had significantly reduced daily evaporative water loss and higher survival relative to the experimental animals. The adrenocortical stress response hence appears essential in facilitating complex phenotypic performance and setting fitness trajectories of individuals from invasive species during range expansion. PMID:23945686

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

2013-10-01

320

7ª Contribuição ao estudo dos Flebotomus (Diptera: Psychodidae): descrição dos machos de 24 novas espécies  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in english The A. and his co-workers captured in trips in the hinterland of Brazil more tham 17.000 flebotomi from which 35 are new ones, 11 discribed by, him in previous papers. The A. found these insects in groups of species living in different habitats, some ones of them not yet known: ondoors, or outdoors [...] attracted by light or animal baits, without Shannon?s trap, in great or small caves, in the jungle in tree?s holes, holes in stones, holes in the soil habited by animals like armadillos, pacas (Aguti paca), wild rats, cururú toad (Bufo sp.). He observed the life history of 13 species: Flebotomus longipalpis Lutz& Neiva, 1912, Flebotomus intermedius Lutz & Neiva, 1912, Flebotomus avellari Costa Lima, 1932, Flebotomus aragãoi costa Lima, 1932, Flebotomus lutzianus Costa Lima, 1932, Flebotomus limai fonseca, 1935, Flebotomus rickardi Costa Lima, 1936, Flebotomus dasipodogeton Castro, 1939, Flebotomus oswaldoi n. sp., Flebotomus villelai n. sp., Flebotomus triacanthus n. sp., Flebotomus longispinus n. sp. And flebotomus travassosi n. sp. He describes the male of 24 n. sp., explaining the differential diagnose of group or nearly allied species. He inclued F. rooti n. sp. And F. hirsutus n. sp. In the sub-genus Shannonomyia. The first one, very allied to F. davisi Root is different from it, for presenting in the dorsal side of the abdomen bristles and not scales and to have the median claspers longer than his inner appendage and F. hirsutus quite different from the others which show 3 spines on distal segment of the upper clasper and for being the only one who presents the bristles of inner appendage of median clasper longer than it. Only the females of F. amazonensis Root and f. chagasi Costa Lima, are known and then it is possible that they belong to one of the species of this sub-genus from whom only the male have been described. F. choti Floch & Abonnenc, captured also at Pará, F. triacanthus n. sp. F. trispinosus n. sp. And F. equatorialis n. sp. Are very related and to this group the A. proposes the same of Pressatia as sub-genus in honor to whom demonstrated the medical importance of the flebotomi, considering F. triacanthus as the type specie of this sub-genus. In this sub-genus the V papal joint is very long, longer than III + IV, the antennae with geniculated spines without posterior outgrowth. At the genitalia the basal segment of the upper clasper presents two types of bristles ou the inner face, arranged in tuft; the distal segment with 3 spines and 2 thin bristles something difficult to see one of them situated near the apical spine and the other on the base of tubercle where the median spine is articulated; the median clasper is unarmed and compressed; the inferior clasper is also unarmed and longer than de basal segment of the upper clasper; the pompeta is longer than the basal segment of the upper clasper. Following it is presented a key for the determination of the males of the four species of this sub-genus. F. micropygus n. sp., F. minasensis n. sp. e F. dandrophylus n. sp., f. shannoni, F. monticolus, F. pestanai, F. lanei and F. cayenensis constitute a group with many similars characters. F. micropygus is the only American species who present ? smaller than ? and for that reason and others is allied to. F. minuts and others related species, but presents two terminal spines on the distal segment of the upper clasper. F. micropygus and f. minasensis are quite different because they have very small genitalia, smaller than their heads. F. dendrophylus presents on the median clasper a naked area near the apex and for this and others characters is different from the others of the group. F. flaviscutellatus n. sp., F. oliverioi, F. intermedius and whithmani, are very allied but the first one can be very easily distinguished because it?s scutellum is light. Flebotomus barrettoi n. sp., F. coutinhoi n. sp., F. aragãoi, F. brasiliensis, F. lutzianus, F. texanus, F. pascalei, F. atroclavatus and F. tejeraae are very allied

Mangabeira Filho, O..

 
 
 
 
321

7ª Contribuição ao estudo dos Flebotomus (Diptera: Psychodidae: descrição dos machos de 24 novas espécies  

Directory of Open Access Journals (Sweden)

Full Text Available The A. and his co-workers captured in trips in the hinterland of Brazil more tham 17.000 flebotomi from which 35 are new ones, 11 discribed by, him in previous papers. The A. found these insects in groups of species living in different habitats, some ones of them not yet known: ondoors, or outdoors attracted by light or animal baits, without Shannon’s trap, in great or small caves, in the jungle in tree’s holes, holes in stones, holes in the soil habited by animals like armadillos, pacas (Aguti paca, wild rats, cururú toad (Bufo sp.. He observed the life history of 13 species: Flebotomus longipalpis Lutz& Neiva, 1912, Flebotomus intermedius Lutz & Neiva, 1912, Flebotomus avellari Costa Lima, 1932, Flebotomus aragãoi costa Lima, 1932, Flebotomus lutzianus Costa Lima, 1932, Flebotomus limai fonseca, 1935, Flebotomus rickardi Costa Lima, 1936, Flebotomus dasipodogeton Castro, 1939, Flebotomus oswaldoi n. sp., Flebotomus villelai n. sp., Flebotomus triacanthus n. sp., Flebotomus longispinus n. sp. And flebotomus travassosi n. sp. He describes the male of 24 n. sp., explaining the differential diagnose of group or nearly allied species. He inclued F. rooti n. sp. And F. hirsutus n. sp. In the sub-genus Shannonomyia. The first one, very allied to F. davisi Root is different from it, for presenting in the dorsal side of the abdomen bristles and not scales and to have the median claspers longer than his inner appendage and F. hirsutus quite different from the others which show 3 spines on distal segment of the upper clasper and for being the only one who presents the bristles of inner appendage of median clasper longer than it. Only the females of F. amazonensis Root and f. chagasi Costa Lima, are known and then it is possible that they belong to one of the species of this sub-genus from whom only the male have been described. F. choti Floch & Abonnenc, captured also at Pará, F. triacanthus n. sp. F. trispinosus n. sp. And F. equatorialis n. sp. Are very related and to this group the A. proposes the same of Pressatia as sub-genus in honor to whom demonstrated the medical importance of the flebotomi, considering F. triacanthus as the type specie of this sub-genus. In this sub-genus the V papal joint is very long, longer than III + IV, the antennae with geniculated spines without posterior outgrowth. At the genitalia the basal segment of the upper clasper presents two types of bristles ou the inner face, arranged in tuft; the distal segment with 3 spines and 2 thin bristles something difficult to see one of them situated near the apical spine and the other on the base of tubercle where the median spine is articulated; the median clasper is unarmed and compressed; the inferior clasper is also unarmed and longer than de basal segment of the upper clasper; the pompeta is longer than the basal segment of the upper clasper. Following it is presented a key for the determination of the males of the four species of this sub-genus. F. micropygus n. sp., F. minasensis n. sp. e F. dandrophylus n. sp., f. shannoni, F. monticolus, F. pestanai, F. lanei and F. cayenensis constitute a group with many similars characters. F. micropygus is the only American species who present ? smaller than ? and for that reason and others is allied to. F. minuts and others related species, but presents two terminal spines on the distal segment of the upper clasper. F. micropygus and f. minasensis are quite different because they have very small genitalia, smaller than their heads. F. dendrophylus presents on the median clasper a naked area near the apex and for this and others characters is different from the others of the group. F. flaviscutellatus n. sp., F. oliverioi, F. intermedius and whithmani, are very allied but the first one can be very easily distinguished because it’s scutellum is light. Flebotomus barrettoi n. sp., F. coutinhoi n. sp., F. aragãoi, F. brasiliensis, F. lutzianus, F. texanus, F. pascalei, F. atroclavatus and F. tejeraae are very allied forming a natural group. The two last ones are not well known

O. Mangabeira Filho

1942-01-01

322

Chiggers recently infesting Spea spp. in Texas, USA, were Eutrombicula alfreddugesi, not Hannemania sp.  

Science.gov (United States)

Upon re-examination of preserved larval chiggers collected from spadefoot toads (Spea bombifrons and Spea multiplicata) in the Southern High Plains of Texas, USA, and identified previously as Hannemania sp., we found them to be Eutrombicula alfreddugesi. A review of previous reports of Eutrombicula spp. chiggers on amphibian hosts provides context for current findings. All members of the genus Hannemania are specialized larval parasites of amphibians, whereas larval E. alfreddugesi are generalist parasites of a wide variety of terrestrial vertebrate hosts that infrequently includes amphibians. Spadefoot toads are previously undocumented hosts for E. alfreddugesi, and observed infestations were unusually prevalent and intense for this chigger on an amphibian host. PMID:21719825

Mertins, James W; Torrence, Shannon M; Sterner, M C

2011-07-01

323

Chiggers recently infesting Spea spp., in Texas, USA, were Eutrombicula alfreddugesi, not Hannemania sp.  

Science.gov (United States)

Upon re-examination of preserved larval chiggers collected from spadefoot toads (Spea bombifrons and Spea multiplicata) in the Southern High Plains of Texas, USA, and identified previously as Hannemania sp., we found them to be Eutrombicula alfreddugesi. A review of previous reports of Eutrombicula spp. chiggers on amphibian hosts provides context for current findings. All members of the genus Hannemania are specialized larval parasites of amphibians, whereas larval E. alfreddugesi are generalist parasites of a wide variety of terrestrial vertebrate hosts that infrequently includes amphibians. Spadefoot toads are previously undocumented hosts for E. alfreddugesi, and observed infestations were unusually prevalent and intense for this chigger on an amphibian host.

Mertins, James W.; Torrence, Shannon M.; Sterner, M. C.

2011-01-01

324

Relação dos anfíbios do Parque Nacional da Lagoa do Peixe, Rio Grande do Sul, Brasil Amphibians list from Lagoa do Peixe National Park, Rio Grande do Sul, Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available Este trabalho apresenta uma relação das espécies de anfíbios do Parque Nacional da Lagoa do Peixe. Durante os anos de 2001 e 2002 os anfíbios foram amostrados através de armadilhas de queda, procura visual e identificação através da atividade de vocalização. O estudo cobriu três diferentes ambientes: a campos e banhados; b dunas costeiras e c praia oceânica. Observou-se a presença de 13 espécies distribuídas em três famílias (Bufonidae, Leptodactylidae e Hylidae. As espécies encontradas são típicas da região costeira do Rio Grande do Sul. O número de espécies foi diferente para cada ambiente, sendo maior no ambiente de campos e banhados onde todas as espécies foram encontradas. Nas dunas costeiras foram encontrados sete espécies de anfíbios, sendo Physalaemus biligonigerus (Cope, 1861 e Bufo arenarum Hensel, 1867 as espécies mais abundantes. Bufo arenarum foi a única espécie encontrada na praia oceânica. De acordo com a literatura, esta espécie parece ser a único anuro capaz de suportar este ambiente que sofre forte influência da salinidade, e o usa para se alimentar.This paper reports the first taxonomic list of amphibians from Lagoa do Peixe National Park. During the years 2001 and 2002 we sampled using Pit Fall Traps, visual searching and identification through vocalization activity. The study covered three different habitats: a plains and swamps; b coastal dunes and c open beach. We observed 13 species into three families (Bufonidae, Leptodactylidae and Hylidae. All species were found along all coastal environment of Rio Grande do Sul. The number of species was different for each environment, being greater in plains and swamps, where all species were found. On the coastal dunes we found seven species of amphibians, being Physalaemus biligonigerus (Cope, 1861 and Bufo arenarum Hensel, 1867 the most abundant. Bufo arenarum was the unique specie that was found in the beach. According to literature, this species seems to be the only anuran able to support this environment which has strong influence of salinity, using it for feeding.

Daniel Loebmann

2005-06-01

325

Expresión heteróloga de ARN mensajeros de Leishmania en ovocitos de anfibios  

Digital Repository Infrastructure Vision for European Research (DRIVER)

La técnica de expresión heteróloga en ovocitos de Xenopus laevis ha sido ampliamente utilizada para la caracterización funcional de canales iónicos. En este estudio se reporta el uso del modelo nativo de ovocitos de Bufo marinus para la expresión heteróloga de ARN poliadenilado (ARNm poli(A)+) de Leishmania amazonensis y la posterior identificación de canales iónicos mediante registros electrofisiológicos utilizando la técnica de voltaje controlado (voltage-clamp). Se logró realiz...

2006-01-01

326

Macroinvertebrates as tadpole food: importance and body size relationships Macroinvertebrados como alimento de girinos: importância e relações com tamanho de corpo  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Macroinvertebrates as food were recorded for three anurans tadpoles: Hyla saxicola (Bokermann, 1964) (Hylidae), Scinax machadoi (Bokermann & Sazima, 1973) (Hylidae), and Bufo rubescens (Lutz, 1925) (Bufonidae). These species are commonly found in the mountain streams at Serra do Cipó National Park, Minas Gerais State, Brazil. Tadpoles were collected in pools of second-order reach in Mascates stream and third and fourth order reaches of Indaiá stream from March-October, 2003. Biometrical dat...

Dutra, Silvia L.; Marcos Callisto

2005-01-01

327

Studies on Alkaline Phosphatase Activity in Amphibians : III. Effects of Inhibitor and Temperature on Alkaline Phosphatases in Japanese Amphibians  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The effects of L-homoarginine, L-phenylalanine, L-phenylalanylglycylglycine and L-leucine and high temperatures on the alkaline phosphatases extracted from the skins, lungs, livers, kidneys, ovaries and small intestines of Rana nigromaculata, Rana japonica, Rana rugosa, Rana limnocharis, Rana catesbeiana, Rhacophorus schlegelii, Hyla arborea japonica, Bufo japonicus and Cynops pyrrhogaster were examined in order to confirm the differences in the stability of alkaline phosphatases to these inh...

2006-01-01

328

76 FR 23879 - Approval and Promulgation of Air Quality Implementation Plans; Indiana; Removal of Vehicle...  

Science.gov (United States)

...g., Confidential Business Information or other...people or to prevent global warming, the state...the advantages and disadvantages of the plans in order...advantages as well as disadvantages to continuing to...added by the Small Business Regulatory...

2011-04-29

329

Microelectronic neural bridge for signal regeneration and function rebuilding over two separate nerves  

Science.gov (United States)

According to the feature of neural signals, a micro-electronic neural bridge (MENB) has been designed. It consists of two electrode arrays for neural signal detection and functional electrical stimulation (FES), and a microelectronic circuit for signal amplifying, processing, and FES driving. The core of the system is realized in 0.5-?m CMOS technology and used in animal experiments. A special experimental strategy has been designed to demonstrate the feasibility of the system. With the help of the MENB, the withdrawal reflex function of the left/right leg of one spinal toad has been rebuilt in the corresponding leg of another spinal toad. According to the coherence analysis between the source and regenerated neural signals, the controlled spinal toad's sciatic nerve signal is delayed by 0.72 ms in relation to the sciatic nerve signal of the source spinal toad and the cross-correlation function reaches a value of 0.73. This shows that the regenerated signal is correlated with the source sciatic signal significantly and the neural activities involved in reflex function have been regenerated. The experiment demonstrates that the MENB is useful in rebuilding the neural function between nerves of different bodies.

Xiaoyan, Shen; Zhigong, Wang; Xiaoying, Lü; Shushan, Xie; Zonghao, Huang

2011-06-01

330

Microelectronic neural bridge for signal regeneration and function rebuilding over two separate nerves  

International Nuclear Information System (INIS)

According to the feature of neural signals, a micro-electronic neural bridge (MENB) has been designed. It consists of two electrode arrays for neural signal detection and functional electrical stimulation (FES), and a microelectronic circuit for signal amplifying, processing, and FES driving. The core of the system is realized in 0.5-?m CMOS technology and used in animal experiments. A special experimental strategy has been designed to demonstrate the feasibility of the system. With the help of the MENB, the withdrawal reflex function of the left/right leg of one spinal toad has been rebuilt in the corresponding leg of another spinal toad. According to the coherence analysis between the source and regenerated neural signals, the controlled spinal toad's sciatic nerve signal is delayed by 0.72 ms in relation to the sciatic nerve signal of the source spinal toad and the cross-correlation function reaches a value of 0.73. This shows that the regenerated signal is correlated with the source sciatic signal significantly and the neural activities involved in reflex function have been regenerated. The experiment demonstrates that the MENB is useful in rebuilding the neural function between nerves of different bodies. (semiconductor integrated circuits)

2011-06-01

331

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

Science.gov (United States)

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

Wittmann, Teresa

332

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

Index Scriptorium Estoniae

Sisu: "mina usun sõna..." ; Tüdruk heitis mulle silma (Silmapartii) ; "Helista siis mulle. Hoolimata sellest, mis kell ma täna magama..." ; Tärkab ; Toad ; "Tee sees on augud. Maa sees on augud..." ; "Puuk on perses. Ai-ai, valus on..." ; Päärätik ; Pliidikütt ; "Ukrainlannast põetaja..." ; Stereonurr ; "Luuletused..."

2007-01-01

333

Kolm põlvkonda ühe katuse all / Jana Rand  

Index Scriptorium Estoniae

Käsitööõpetaja Eva ja ärimees Peeter Pree avatud planeeringuga kodu Vastse-Kuustes. Sisekujunduse autor Eva Pree. Terrasiga eramu fassaadi kaunistab vapp, magamistuba on rõduga, toad on sisustatud klassikalise mööbliga, viimistluses on kasutatud pastelseid toone. Erinevatel tasapindadel aias on kiviktaimla. 10 ill

Rand, Jana, 1963-

2003-01-01

334

Pääsupesad 1-5 : [luuletused] / Saila Susiluoto ; tõlkinud Hasso Krull  

Index Scriptorium Estoniae

Sisu: Pääsupesad:1-5 ; Viis muinasjuttu Espoo ridamajadest: 1-5 ; Tüdrukumuinasjutt ; Muinasjutt maast ; Naiste tualettruum ; Relvakamber ; Koridoriaken öösel ; Õe ja venna toast viib trepp vanasse kartulikeldrisse, nüüd moosikeldrisse ; Varisev tuba mehaanilise luigega ; Toas kasvab palavikupuu, toast läbi ; Lühike trepp ; Sinise magamistoa rõdu ; Vee toad. Eluloolisi andmeid autori kohta lk. 278

Susiluoto, Saila

2004-01-01

335

Ergutavad, lohutavad ja ravivad värvid / Jana Rand  

Index Scriptorium Estoniae

Altmõisa puhkemaja Läänemaal Tuuru külas. Hoone sisekujunduse on teinud Heli Tuksam, abiks olid kunstnikud Piret Veski ja Tuuli Puhvel ning Tartu Kõrgema Kunstikooli üliõpilased. Toad on kujundatud erinevates värvitoonides. Fuajees on mosaiikpõrand. Kasutatud ökoloogilisi ehitus- ja viimistlusmaterjale. Ill.: välisvaade 7 sisevaadet, värv.

Rand, Jana, 1963-

2005-01-01

336

Kaks kodu ühe katuse all / Ado Eigi  

Index Scriptorium Estoniae

Arhitekt Maire Annuse projekteeritud, 1997. a. valminud kahekorruseline kellerdatud kaksikelamu, mille keskel on kaht poolt siduva lülina avatud trepihallid. Kummagi elamupoole keskele on projekteeritud kolme korrust läbiv santehniliste ruumide blokk. Avarast kaminaga elutoast avaneb pääs terrassile ja aeda. Keldrikorrusel on puhkeruum, saun, väike bassein. Teisel korrusel on tütarde ja vanemate toad. Tütarde tubade kardinate autor - Kati Sihver

Eigi, Ado, 1938-2008

1998-01-01

337

Contributions to an up-date of the Red List of wild species from the Danube Delta Biosphere Reserve. Part I. Amphibians  

Directory of Open Access Journals (Sweden)

Full Text Available Up to the present in the Danube Delta Biosphere Reserve (DDBR there were recorded 11 native amphibian taxa (10 species and one hybrid. The first Red List of the wild species from DDBR was drafted in 1999 and printed in 2000. Based on the results of investigations carried out since 2000 and taking into account the developments related to criteria for conservation status of wild species (on world-wide level, on European continental level, on EU level and on national level, the present work provides details on the proposals to consider the following conservations status to amphibians occurring in the DDBR: Triturus dobrogicus (widely distributed, but not frequent species – Vulnerable; Triturus vulgaris (widely distributed, but not frequent species – Vulnerable; Bombina bombina (widely distributed, frequent species - Least Concern; Pelobates fuscus (widely distributed, relatively frequent species - Least Concern; Pelobates syriacus (a species distributed in the southern part of DDBR and at the limit of the continental plateau– Vulnerable; Bufo bufo (species occurring only in the proper Danube Delt and less adapted to regularely flooded wetlands with high water-level variations - Least Concern; Bufo viridis (widely distributed, frequent species, excepting the reed-dominated areas - Least Concern; Hyla arborea (widely distributed, relatively frequent species - Least Concern; Rana lessonae (species recorded only in the proper Danube Delt, but probably more frequent than is it known in the present - Least Concern; Rana ridibunda (widely distributed, frequent species - Least Concern and Rana kl. esculenta (widely distributed, frequent amphibian - Least Concern.

TÖRÖK Zsolt Csaba

2013-12-01

338

Effects of environmental radiation of Kori nuclear power plant on the human population  

International Nuclear Information System (INIS)

In order to clarify and protect the effects of environmental radiation according to the operation of Kori nuclear power plant on human population, the base line survey for the human monitoring, the fauna of land nocturnal insects, and the karyotypes of amphibian species which have been living around the power plant site were carried out. ''Kilchunri'' population which took for the human monitoring lie within a 2km distance from power plant site. Human monitoring, house and food characteristics, individual experience of X-ray exposures, human chromosome analysis and fauna of nocturnal land insects were surveyed and expressed in numerical tables. Chromosome number obtained from the amphibia which were collected around the power plant area was as follows; Kaloula borealis 2N=30, Rana amurensis 2N=26, Rana dybouskii 2N=24, Rana rugosa 2N=26, Rana migromaculata 2N=26, Rana plancyi 2N=26, Bombina orientalis 2N=24, Hyla arborea 2N=24, Bufo stejnegeri 2N=22, and Bufo bufo 2N=22. (author)

1979-01-01

339

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 natrix, Natrix tessellata, Vipera ammodytes and also Rana kl. esculenta populations. Some species of amphibians (Pelobates fuscus, Pelobates syriacus that were only previously known inform the lower regions of the Danube’s meadow and in the vicinity of the Black Sea, were recorded in the high areas of northern Dobrudja. Also here, all three forms of the green frogs’ complex documented for Romania have been encountered, but Rana lessonae and Rana esculenta are very rare, being found only in the north. The central sectors of Dobrudja are severely impacted by human activities, almost completely cleared as a result of agriculture and showed very low number of herpetofauna species as being present. The most important areas for the herpetofauna are the northern and south-western regions.

Horia V. BOGDAN

2006-12-01

340

Preliminary data regarding the distribution and status of the herpetofauna in Ia?i County (Romania  

Directory of Open Access Journals (Sweden)

Full Text Available 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, Anguis fragilis, Lacerta agilis, Lacerta viridis, Natrix natrix, Coronella austriaca, Zamenis longissimus, Vipera berus and Vipera ursiniiand hybrids between B. bombina and B. variegata and between P. ridibundus and P. lessonae (Pelophylax kl. esculentus were recorded in the 62 investigated localities in Ia?i County. Salamandra salamandra is recorded for the first time in the area, east of the Siret river, being situated at its eastern distribution limit for Europe. Among the most important results of our study is the identification of a new locality for one of the rarest European reptiles, Vipera ursinii. One amphibian (Lissotriton montandoni and one reptile (Elaphe sauromates have previously been recorded in our study area but we were unable to reconfirm their presence.

Alexandru STRUGARIU

2008-11-01

 
 
 
 
341

Acetylcholine-like activity in the fruit of the black nightshade (Solanaceae).  

Science.gov (United States)

The presence of acetylcholine in aqueous extracts of the fruit of Solanum nigrum Linn. (black nightshade) has been established based upon the following pharmacological tests: a) isotonic contraction of the isolated toad rectus abdominis; b) negative chronotropic and inotropic action on the isolated toad heart; c) isotonic contraction of the isolated guinea pig's ileum; d) isotonic contraction of the rat's isolated jejunum; 3) decrease on the cat's arterial blood pressure; f) secretory effects on the rat's submaxillary gland. These actions were selectively blocked by curate or atropine and disappeared after incubation of the extract at 37 C with plasma. Further evidence showing that the fruit of the black nightshade contains acetylcholine was obtained by chromatographic separation of the aqueous extract. The average content of acetylcholine was found to be 250 micrograms/g of fruit. PMID:122174

de Melo, A C; Perec, C J; Rubio, M C

1978-01-01

342

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 gathered data from 1990--1997 (excluding 1992), they plan to determine if patterns can be found in the annual and seasonal population changes of four species of reptiles and amphibians over the past seven years. The four species studied are the Woodhouse toad, the western chorus frog, the many-linked skink, and the plateau striped whiptail lizard. Statistical analysis results show that significant changes occurred on a seasonal basis for the western chorus frog and the many-lined skink. Results indicate a significant difference in the annual population of the Woodhouse toad.

Nelson, E.I.; Haarmann, T.; Keller, D.C.; Foxx, T.

1998-11-01

343

Diet of Brachycephalus brunneus (Anura: Brachycephalidae): in the Atlantic Rainforest of Paraná, southern Brazil</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">Saddleback <span class="hlt">toads</span> (Brachycephalidae: Brachycephalus) are a remarkable group of highly endemic species from the southern Atlantic Rainforest of Brazil. They are brightly colored, diurnal, minute frogs that live in the leaf litter of high-elevation cloud forests. Little is known about the natural history of these frogs, particularly their diet. In the present study we provide the first published account of a Brachycephalus species diet. Specimens of Brachycephalu...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::9cf702484fc13a88bfe675c1b62aa4c7"> <span id="translatedtitle">Sound level discrimination by gray treefrogs in the presence and absence of chorus-shaped noise</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">An important aspect of hearing and acoustic communication is the ability to discriminate differences in sound level. Little is known about level discrimination in anuran amphibians (frogs and <span class="hlt">toads</span>), for which vocal communication in noisy social environments is often critical for reproduction. This study used two-choice phonotaxis tests to investigate the ability of females of Cope’s gray treefrog (Hyla chrysoscelis) to discriminate between two advertisement calls differing only in sound pr...</p> <div class="credits"> <p class="dwt_author">Bee, Mark A.; Ve?lez, Alejandro; Forester, James D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">345</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=doajarticles::b0814d6baf7ad03deae714445c2f18af"> <span id="translatedtitle">Gluttony Causes Death in Juvenile Puff Adder Bitis arietans</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">Little is known about the predator/prey relationship in reptiles. The puff adder Bitis arietans is known to feed on a variety of food items, their diet consisting mainly of rodents, while birds, lizards and <span class="hlt">toads</span> may be included (Broadley 1983, FitzSimons' Snakes of Southern Africa, Johannesburg: Delta Books). Pitman (1974, The Snakes of Uganda, Glasgow: Wheldon and Wesley) recorded larger prey for puff adders in East Africa, while Robertson, Chapman & Chapman (1965, Puku 3: 149-170) repo...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=doajarticles::95881342ee0661c340b9c0928fbda2e3"> <span id="translatedtitle">Solar Radiation Alters Toxicity of Carbofuran: Evidence from Empirical Trials with Duttaphyrnus melanostictus</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">In the present study we investigated the potential of natural solar radiation to alter the toxicity of a commonly used carbamate pesticide, carbofuran, on tadpoles of the Common Asian <span class="hlt">Toad</span> Duttaphrynus melanostictus. A single exposure trial was conducted over 96 hrs with three concentrations (150, 250 and 500 µgl-1) of photo-irradiated and non-irradiated carbofuran. Results show that photo-irradiation markedly reduced the toxicity of carbofuran as evident by its effects on three ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=doajarticles::4ddbbe8bc9b061e1b637f51d1195b88a"> <span id="translatedtitle">Solar Radiation Alters Toxicity of Carbofuran: Evidence from Empirical Trials with Duttaphyrnus melanostictus</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">In the present study we investigated the potential of natural solar radiation to alter the toxicity of a commonly used carbamate pesticide, carbofuran, on tadpoles of the Common Asian <span class="hlt">Toad</span> Duttaphrynus melanostictus. A single exposure trial was conducted over 96 hrs with three concentrations (150, 250 and 500 µgl-1) of photo-irradiated and non-irradiated carbofuran. Results show that photo-irradiation markedly reduced the toxicity of carbofuran as evident by its effects on three end points, ...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=doajarticles::3abb7eb9fddbaf245c5510ad5d51409d"> <span id="translatedtitle">Chemical Evaluation of the Nutrient Composition of Some Unconventional Animal Protein Sources</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">A trial was conducted to assess the nutrient composition of some novel feed ingredients so as to enhance livestock development and human protein intake. Ten (10) unconventional protein sources which include fish, crayfish, frog, shrimps, crabs, squilla, <span class="hlt">toads</span> and grasshopper were harvested, processed and analyzed for their proximate and mineral (macro) composition using internationally established procedures. The results showed that the samples had percent crude protein that ranged fro...</p> <div class="credits"> <p class="dwt_author">Ojewola, G. S.; Udom, S. F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=doajarticles::baf4ead0b2f431113f5789a7c014b595"> <span id="translatedtitle">Expression pattern of three-finger toxin and phospholipase A<sub>2 </sub>genes in the venom glands of two sea snakes, <it>Lapemis curtus </it>and <it>Acalyptophis peronii</it>: comparison of evolution of these toxins in land snakes, sea kraits and sea snakes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">Abstract Background Snake venom composition varies widely both among closely related species and within the same species, based on ecological variables. In terrestrial snakes, such variation has been proposed to be due to snakes' diet. Land snakes target various prey species including insects (arthropods), lizards (reptiles), frogs and <span class="hlt">toads</span> (amphibians), birds (aves), and rodents (mammals), whereas sea snakes target a single vertebrate class (fishes) and often specialize on ...</p> <div class="credits"> <p class="dwt_author">Pahari Susanta; Bickford David; Fry Bryan G; Manjunatha, Kini R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::26592638aa8ade99ce719e6e86cb0a41"> <span id="translatedtitle">Potential Component Allee Effects and Their Impact on Wetland Management in the Conservation of Endangered Anurans</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">Effective management of wetland quantity and quality is crucial for effective conservation of declining amphibian populations. In particular, frogs and <span class="hlt">toads</span> that employ aggregative breeding strategies may suffer negative population impacts in response to changes in availability of aquatic breeding habitat, including overabundance of suitable habitat, if density of conspecifics attending aggregations is positively correlated with reproductive success. Here we document such a positive relation...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::bba088efe68223807ef973cef935bb00"> <span id="translatedtitle">Endemic predators, invasive prey and native diversity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">Interactions between native diversity and invasive species can be more complex than is currently understood. Invasive ant species often substantially reduce diversity in the native ants diversity that act as natural control agents for pest insects. In Indonesia (on the island of Sulawesi), the third largest cacao producer worldwide, we show that a predatory endemic <span class="hlt">toad</span> (Ingerophrynus celebensis) controls invasive ant (Anoplolepis gracilipes) abundance, and positively affects native ant diver...</p> <div class="credits"> <p class="dwt_author">Wanger, Thomas C.; Wielgoss, Arno C.; Motzke, Iris; Clough, Yann; Brook, Barry W.; Sodhi, Navjot S.; Tscharntke, Teja</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::92212c094be784fcb6c7066d7fd55bb6"> <span id="translatedtitle">Why are blue visual pigments blue? A resonance Raman microprobe study.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">A resonance Raman microscope has been developed to study the structure of the retinal prosthetic group in the visual pigments of individual photoreceptor cells. Raman vibrational spectra are obtained by focusing the probe laser on intact photoreceptors frozen on a 77 K cold stage. To elucidate the mechanism of wavelength regulation in blue visual pigments, we have used this apparatus to study the structure of the chromophore in the 440-nm absorbing pigment found in "green rods" of the <span class="hlt">toad</span> (B...</p> <div class="credits"> <p class="dwt_author">Loppnow, G. R.; Barry, B. A.; Mathies, R. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/15562621"> <span id="translatedtitle">Observations on myiasis by the calliphorids, Bufolucilia silvarum and Bufolucilia elongata, in wood frogs, Rana sylvatica, from southeastern Wisconsin.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.science.gov/">Science.gov (United States)</a></p> <p class="result-summary">Larvae of certain species of blowflies (Calliphoridae) can cause myiasis in frogs and <span class="hlt">toads</span>, but there are few reports from North American amphibians. Of these, most are from <span class="hlt">toads</span> (bufonids). In this study, we observe primary myiasis in a population of juvenile wood frogs, Rana sylvatica, collected on 22-23 August 2003, from southeastern Wisconsin and compare our observations with previous studies on myiasis from <span class="hlt">toads</span>. Two (5%) of 39 frogs were infected by the blow fly Bufolucilia silvarum, with an intensity of 28 and 31, whereas 1 (2.5%) of 39 frogs was infected by the blow fly Bufolucilia elongata with an intensity of 14. We found that (1) B. silvarum lay eggs on healthy wood frogs, (2) eggs hatch, with first-instar maggots penetrating under the skin, (3) maggots develop to mature third instars within 13-16 hr of egg hatching, (4) maggots kill the host within 7-47 hr of egg hatching, and (5) maggots consume the entire frog carcass reducing it to bones within 42-59 hr of egg hatching. Our observations on the time of death and how quickly carcasses of wood frogs were consumed by these maggots compared with previous studies on <span class="hlt">toads</span> suggest that finding infected juvenile wood frogs may be uncommon. Therefore, myiasis by these flies on wood frogs and other small terrestrial anurans may be a phenomenon that is much more common than is currently observed. This is the first report of B. silvarum and B. elongata causing myiasis in wood frogs. PMID:15562621</p> <div class="credits"> <p class="dwt_author">Bolek, Matthew G; Janovy, John</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______330::98c1579feff90e1ea44c99e22027539b"> <span id="translatedtitle">No detection of chytrid in first systematic screening of Bombina variegata pachypus (Anura: Bombinatoridae) in Liguria, northern Italy</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">The Apennine Yellow-bellied <span class="hlt">toad</span> Bombina variegata pachypus, a small anuran endemic to peninsular Italy, has been declining throughout its range over the last 30 years. Although mortality by chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis, was first reported for the species in 2004, its role in the decline has not yet been assessed. Between 2011 and 2012 we sampled eight populations of B. v. pachypus in Liguria, northern Italy, swabbing 86 and 143 individuals respectivel...</p> <div class="credits"> <p class="dwt_author">Canessa, Stefano; Martel, An; Pasmans, Frank</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::3b3def574b1639553e266522083fea67"> <span id="translatedtitle">Widespread Occurrence of Batrachochytrium dendrobatidis in Contemporary and Historical Samples of the Endangered Bombina pachypus along the Italian Peninsula</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">Batrachochytrium dendrobatidis is considered a main driver of the worldwide declines and extinctions of amphibian populations. Nonetheless, fundamental questions about its epidemiology, including whether it acts mainly as a “lone killer” or in conjunction with other factors, remain largely open. In this paper we analysed contemporary and historical samples of the endangered Apennine yellow-bellied <span class="hlt">toad</span> (Bombina pachypus) along the Italian peninsula, in order to assess the presence of the ...</p> <div class="credits"> <p class="dwt_author">Canestrelli, Daniele; Zampiglia, Mauro; Nascetti, Giuseppe</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::d89017d17134de05b44337a3e613787d"> <span id="translatedtitle">Removing the rubbish: frogs eliminate foreign objects from the body cavity through the bladder</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">During the course of a telemetry study on three species of Australian frogs (Litoria caerulea, Litoria dahlii and Cyclorana australis), we found that many of the surgically implanted transmitters had migrated into the bladder. We subsequently implanted small beads into L. caerulea and they were expelled from the body in 10–23 days. Beads implanted into cane <span class="hlt">toads</span> (Rhinella marina) to document the process were either expelled or were enveloped into the bladder. This appears to be a unique pa...</p> <div class="credits"> <p class="dwt_author">Tracy, Christopher R.; Christian, Keith A.; Mcarthur, Lorrae J.; Gienger, C. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=doajarticles::ef80504065c2be0dac05ffe926b8fca9"> <span id="translatedtitle">Frog Swarms: Earthquake Precursors or False Alarms?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">In short-term earthquake risk forecasting, the avoidance of false alarms is of utmost importance to preclude the possibility of unnecessary panic among populations in seismic hazard areas. Unusual animal behaviour prior to earthquakes has been reported for millennia but has rarely been scientifically documented. Recently large migrations or unusual behaviour of amphibians have been linked to large earthquakes, and media reports of large frog and <span class="hlt">toad</span> migrations in areas of high seismic risk s...</p> <div class="credits"> <p class="dwt_author">Grant, Rachel A.; Hilary Conlan</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::6a919a2a6132fb1eb309aed147dd59ef"> <span id="translatedtitle">Purification and characterization of the amiloride-sensitive sodium channel from A6 cultured cells and bovine renal papilla.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">The amiloride-binding Na+ channel protein of high electrical resistance epithelia was solubilized and purified from cultured A6 <span class="hlt">toad</span> kidney cells and bovine renal papilla. Purification was assessed by enrichment in [3H]methylbromoamiloride specific binding. Chromatography of 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS)-solubilized plasma membrane vesicles on agarose-immobilized wheat-germ agglutinin provided a 130-fold enrichment of the amiloride-binding component compare...</p> <div class="credits"> <p class="dwt_author">Benos, D. J.; Saccomani, G.; Brenner, B. M.; Sariban-sohraby, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::96ebd484222c811768263ef87316fad3"> <span id="translatedtitle">Sexual Hearing: The influence of sex hormones on acoustic communication in frogs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">The majority of anuran amphibians (frogs and <span class="hlt">toads</span>) use acoustic communication to mediate sexual behavior and reproduction. Generally, females find and select their mates using acoustic cues provided by males in the form of conspicuous advertisement calls. In these species, vocal signal production and reception are intimately tied to successful reproduction. Research with anurans has demonstrated that acoustic communication is modulated by reproductive hormones, including gonadal steroids and...</p> <div class="credits"> <p class="dwt_author">Arch, Victoria S.; Narins, Peter M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=doajarticles::688ebda9d7713876e54856d4dbd5dee5"> <span id="translatedtitle">Distribution of tadpoles of <em>Ollotis occidentalis</em> (Amphibia: Anura: Bufonidae) along the Río Salado, Puebla, México</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">We examined monthly variation in the characteristics of river sections along the Río Salado (Puebla, Mexico) and how these factors were associated with the dis- tribution of the tadpoles of the <span class="hlt">toad</span> <em>Ollotis occidentalis</em>. Tadpoles were observed in the river in March 2007, and from November 2007 through February 2008 and were only found in the main river channel. Sections of the Río Salado with tadpoles were deeper, wider, and longer than sections without tadp...</p> <div class="credits"> <p class="dwt_author">Woolrich-pin?a, Guillermo A.; Smith, Geoffrey R.; Luis Oliver-López; Monica Barbosa Morales; Lemos-espinal, Julio A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:90%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://worldwidescience.org/wws/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_17");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://worldwidescience.org/wws/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a style="font-weight: bold;">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_19");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://worldwidescience.org/wws/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://worldwidescience.org/wws/images/icon.last.18x20.png" alt="Last Page" /></a> </div> <div id="refine_search_form_div" style="right:140px"> <form id="simple_search_form" method="post" action="http://worldwidescience.org/cgi-bin/wwsproxy.pl" onsubmit="return ValidationUtils.validateSimpleSearch('refine_search_terms');"> <input name="viewId" value="view0" type="hidden" /><input name="ssid" value="" type="hidden" /> <input id="search_terms" name="expression" value="natterjack toad bufo" class="TextInput" type="text" style="width:250; height:17pt"/> <input name="ssid" value="" type="hidden" /><button type="submit" class="search_submit" id="search_submit" title="New Search">Search</button> </form>  <br>  </div> </div> </div><!-- page_18 div --> <div id="page_19" class="hiddenDiv"> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:90%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://worldwidescience.org/wws/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://worldwidescience.org/wws/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a style="font-weight: bold;">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_20");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://worldwidescience.org/wws/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://worldwidescience.org/wws/images/icon.last.18x20.png" alt="Last Page" /></a> </div> <div id="refine_search_form_div" style="right:140px"> <form id="simple_search_form" method="post" action="http://worldwidescience.org/cgi-bin/wwsproxy.pl" onsubmit="return ValidationUtils.validateSimpleSearch('refine_search_terms');"> <input name="viewId" value="view0" type="hidden" /><input name="ssid" value="" type="hidden" /> <input id="search_terms" name="expression" value="natterjack toad bufo" class="TextInput" type="text" style="width:250; height:17pt"/> <input name="ssid" value="" type="hidden" /><button type="submit" class="search_submit" id="search_submit" title="New Search">Search</button> </form>  <br>  </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">361</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24664895"> <span id="translatedtitle">Effect of a Punica granatum enriched diet on immunocompetence in Rhinella marina.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.science.gov/">Science.gov (United States)</a></p> <p class="result-summary">Direct ingestion of plant materials has been shown to have immunomodulatory effects on a variety of herbivores. Studies have also shown that compounds ingested indirectly by predators through prey items can affect the general physiology of the ingesting organism. Relatively little data exists, however, concerning the modulation of a predator's immune system via compounds obtained indirectly through prey. In this study, we sought to determine if the immune-stimulating properties of Punica granatum (pomegranate) could be conveyed from a prey organism, Acheta domestica, to a predator, Rhinella marina, through diet specialization. Experimental crickets were fed a diet of agar supplemented with 10?mg/mL of lyophilized, powdered, whole pomegranate while control crickets were fed unadulterated agar. Experimental <span class="hlt">toads</span> consumed a diet consisting of crickets fed the pomegranate-enriched diet, while control <span class="hlt">toads</span> consumed a diet consisting of crickets fed the standard agar diet. Blood samples were taken weekly and leukocyte profiles and neutrophil phagocytic activity were determined for all <span class="hlt">toads</span> over an 8-week period. Complement activity was measured at 6 weeks. <span class="hlt">Toads</span> fed the pomegranate-enriched diet showed altered leukocyte profiles as evidenced by an increase in circulating eosinophil number and a decrease in the number of circulating lymphocytes, monocytes, and basophils as compared to controls, indicating an immunomodulatory effect of the pomegranate-enhanced diet. These results suggest that pomegranate-derived immunomodulatory compounds can be transferred from prey to predator, and suggests that the flora in the environment where insectivores forage could have a significant effect on the physiology of the animal. J. Exp. Zool. 321A: 316-323, 2014. © 2014 Wiley Periodicals, Inc. PMID:24664895</p> <div class="credits"> <p class="dwt_author">Parker, Anna N; Ward, Chelsea K; Estes, N Robert</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22561289"> <span id="translatedtitle">Developmental reversal in neuropeptide Y action on feeding in an amphibian.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.science.gov/">Science.gov (United States)</a></p> <p class="result-summary">Neuropeptide Y (NPY) is expressed in the hypothalamus where it exerts orexigenic actions within the feeding control circuit. While NPY stimulates feeding in juvenile and adult animals, it is not known whether NPY influences food intake at earlier life stages. We investigated a role for NPY in regulating feeding at two stages of the life cycle of an amphibian, the Western spadefoot <span class="hlt">toad</span> Spea hammondii. We administered NPY by intracerebroventricular (i.c.v.) injection to juvenile <span class="hlt">toads</span> or prometamorphic tadpoles, and monitored locomotion, feeding behavior and/or food intake. Injection of NPY (20 or 200 ng/g BW) into juvenile <span class="hlt">toads</span> decreased the latency to, and increased the number of strikes at prey, and the number of crickets eaten compared to uninjected or vehicle-injected controls. By contrast, injection of NPY (0.02-20 ng/g BW) into prometamorphic tadpoles caused a dose-dependent decrease in time spent foraging compared to controls. Blocking NPY signaling in the prometamorphic tadpole brain by i.c.v. injection of a general NPY receptor antagonist increased foraging, and partly blocked the action of exogenous NPY on foraging. Taken together, our findings show a developmental reversal in NPY actions on feeding in an amphibian, with the peptide having a characteristic orexigenic action in the juvenile <span class="hlt">toad</span>, but an inhibitory action on foraging in the prometamorphic tadpole. The anorexigenic action of NPY in the tadpole correlates with a decrease in feeding that occurs at metamorphic climax when the tadpole's gut and cranium remodels for the transition to a carnivorous diet. PMID:22561289</p> <div class="credits"> <p class="dwt_author">Crespi, Erica J; Denver, Robert J</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::a7b3e47f600f1b3f08d9e5460c96d37d"> <span id="translatedtitle">Anuran radiations and the evolution of tadpole morphospace</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">Anurans (frogs and <span class="hlt">toads</span>) are unique among land vertebrates in possessing a free-living larval stage that, parallel to adult frogs, diversified into an impressive range of ecomorphs. The tempo and mode at which tadpole morphology evolved through anuran history as well as its relationship to lineage diversification remain elusive. We used a molecular phylogenetic framework to examine patterns of morphological evolution in tadpoles in light of observed episodes of accelerated lineage diversific...</p> <div class="credits"> <p class="dwt_author">Roelants, Kim; Haas, Alexander; Bossuyt, Franky</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::153b6f413439a7be5d4da8d1ddf2d04a"> <span id="translatedtitle">Erythrocyte differentiation during the metamorphic hemoglobin switch of Rana catesbeiana.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">Anurans (frogs and <span class="hlt">toads</span>) switch from tadpole to adult hemoglobin synthesis during metamorphosis. A number of workers have attempted to determine whether tadpole and adult Hb types are expressed in the same or different erythroid cells during the switch. If the different Hb types are found in different cells during the transition, the switch in globin gene expression occurs at an early stage of cellular differentiation. Previous studies, in which immunocytochemical techniques were used to app...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=doajarticles::d13942dc3eff130cb75ad183b0c1a0c6"> <span id="translatedtitle">Widespread disruptive selection in the wild is associated with intense resource competition</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">Abstract Background Disruptive selection has been documented in a growing number of natural populations. Yet, its prevalence within individual systems remains unclear. Furthermore, few studies have sought to identify the ecological factors that promote disruptive selection in the wild. To address these issues, we surveyed 15 populations of Mexican spadefoot <span class="hlt">toad</span> tadpoles, Spea multiplicata, and measured the prevalence of disruptive selection acting on resource-use ph...</p> <div class="credits"> <p class="dwt_author">Martin Ryan A; Pfennig David W</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::991c03548d36dc8c864fc277b82cc71b"> <span id="translatedtitle">Rapid voltage-dependent dissociation of scorpion alpha-toxins coupled to Na channel inactivation in amphibian myelinated nerves</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">The voltage-dependent action of several scorpion alpha-toxins on Na channels was studied in <span class="hlt">toad</span> myelinated nerve under voltage clamp. These toxins slow the declining phase of macroscopic Na current, apparently by inhibiting an irreversible channel inactivation step and thus permitting channels to reopen from a closed state in depolarized membranes. In this article, we describe the rapid reversal of alpha- toxin action by membrane depolarizations more positive than +20 mV, an effect not achie...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=od_______908::c7b54e098d92e8f94a72a0654f22279b"> <span id="translatedtitle">Calcium dependence of the activation and inactivation kinetics of the light-activated phosphodiesterase of retinal rods</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">The Ca2+ dependence of the kinetics and light sensitivity of light- activated phosphodiesterase was studied with a pH assay in <span class="hlt">toad</span> and bovine rod disk membranes (RDM), and in a reconstituted system containing GTP-binding protein, phosphodiesterase and rhodopsin kinase. Three statistics, peak hydrolytic velocity, turnoff time, and time to peak velocity, were measured. ATP decreased phosphodiesterase light sensitivity nearly 10-fold and accelerated the dim-flash kinetics of cGMP hydrolysis whe...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006SPIE.6354E...2L"> <span id="translatedtitle">Ultrafast optical header processing with DPSK for asynchronous optical packet switch</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.science.gov/">Science.gov (United States)</a></p> <p class="result-summary">An optical header extraction and recognition structure was presented in the paper. The optical header is extracted by the improved i<span class="hlt">TOAD</span> structure with DPSK modulation, while the header recognition is realized by discrete time stretch technology with super-continuum pulse to slow down the optical header speed for the high-speed asynchronous optical packet switch. Analysis and Experimental results shows that the i<span class="hlt">TOAD</span> with time stretch technique can enlarge the output header 20dB and improve the switching ratio to 15dB when the input pulse is only 0.1pJ. By adjusting the tunable FDL length, the two pulses after the coupler switching have the ? phase shift in the i<span class="hlt">TOAD</span> SOA. The structure can slow down the high-speed optical header speed. Furthermore, the low speed header has the low latency time decreases (latency time less than 100?s) and overcomes the drawbacks of time bandwidth limitation associated with dispersion in long lengths of fiber. The system is highly scalable, lower power consumption and photonic integration.</p> <div class="credits"> <p class="dwt_author">Liu, Huanlin; Pan, Yingjun; Chen, Qianbin</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/20878751"> <span id="translatedtitle">Variation in the hormonal stress response among larvae of three amphibian species.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.science.gov/">Science.gov (United States)</a></p> <p class="result-summary">In a series of studies, we examined how larval corticosterone treatment for several species of amphibians can impact fitness parameters both during exposure and after metamorphosis. We completed confinement stress series on larvae of three species in natural/semi-natural conditions: wood frogs (Rana sylvatica), Jefferson salamanders (Ambystoma jeffersonianum), and Eastern spadefoot <span class="hlt">toads</span> (Scaphiopus holbrooki). Two of the species had a typical vertebrate response of increasing corticosterone with confinement. However, Eastern spadefoot <span class="hlt">toads</span>, which have a very short developmental period before metamorphosis, did not show any increase in corticosterone in response to confinement. In a second study, we treated the three species with a low and a high concentration of corticosterone (0.001 and 0.01?µM dissolved in tank water) in the laboratory and examined effects on growth. Although we were successful in raising baseline corticosterone levels with our high corticosterone concentrations, this did not translate into changes in mean larval growth for any of the three species. The larval treatments also did not appear to translate into differences in the juvenile response to confinement stress after metamorphosis. Although juvenile wood frogs did respond to confinement with increasing corticosterone, there was no variation based on larval treatment. As with the larval responses, the juvenile Eastern spadefoot <span class="hlt">toads</span> did not have a hormonal response to confinement. In summary, while our larval corticosterone exposures did elevate baseline corticosterone levels, we did not see effects of exposure on growth or any latent effects of larval exposure on juvenile responses to confinement. PMID:20878751</p> <div class="credits"> <p class="dwt_author">Belden, Lisa K; Wingfield, John C; Kiesecker, Joseph M</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">370</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81752005000200006&lang=en"> <span id="translatedtitle">Relação dos anfíbios do Parque Nacional da Lagoa do Peixe, Rio Grande do Sul, Brasil / Amphibians list from Lagoa do Peixe National Park, Rio Grande do Sul, Brazil</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.scielo.org/php/index.php?lang=en">Scientific Electronic Library Online (English)</a></p> <p class="result-summary">Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Este trabalho apresenta uma relação das espécies de anfíbios do Parque Nacional da Lagoa do Peixe. Durante os anos de 2001 e 2002 os anfíbios foram amostrados através de armadilhas de queda, procura visual e identificação através da atividade de vocalização. O estudo cobriu três diferentes ambientes [...] : a) campos e banhados; b) dunas costeiras e c) praia oceânica. Observou-se a presença de 13 espécies distribuídas em três famílias (Bufonidae, Leptodactylidae e Hylidae). As espécies encontradas são típicas da região costeira do Rio Grande do Sul. O número de espécies foi diferente para cada ambiente, sendo maior no ambiente de campos e banhados onde todas as espécies foram encontradas. Nas dunas costeiras foram encontrados sete espécies de anfíbios, sendo Physalaemus biligonigerus (Cope, 1861) e <span class="hlt">Bufo</span> arenarum Hensel, 1867 as espécies mais abundantes. <span class="hlt">Bufo</span> arenarum foi a única espécie encontrada na praia oceânica. De acordo com a literatura, esta espécie parece ser a único anuro capaz de suportar este ambiente que sofre forte influência da salinidade, e o usa para se alimentar. Abstract in english This paper reports the first taxonomic list of amphibians from Lagoa do Peixe National Park. During the years 2001 and 2002 we sampled using Pit Fall Traps, visual searching and identification through vocalization activity. The study covered three different habitats: a) plains and swamps; b) coastal [...] dunes and c) open beach. We observed 13 species into three families (Bufonidae, Leptodactylidae and Hylidae). All species were found along all coastal environment of Rio Grande do Sul. The number of species was different for each environment, being greater in plains and swamps, where all species were found. On the coastal dunes we found seven species of amphibians, being Physalaemus biligonigerus (Cope, 1861) and <span class="hlt">Bufo</span> arenarum Hensel, 1867 the most abundant. <span class="hlt">Bufo</span> arenarum was the unique specie that was found in the beach. According to literature, this species seems to be the only anuran able to support this environment which has strong influence of salinity, using it for feeding.</p> <div class="credits"> <p class="dwt_author">Daniel, Loebmann; João P., Vieira.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">371</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://inis.iaea.org/search/search.aspx?orig_q=RN:8321391"> <span id="translatedtitle">Electrophoretic pattern of blood serum proteins of some of the vertebrates of Pakistan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://inis.iaea.org/search/">International Nuclear Information System (INIS)</a></p> <p class="result-summary">The electrophoretic pattern of blood serum proteins of some of the common fishes e.g. Catla catla, Cirrhina mrigala, Channa punctatus, Channa marulius, Wallago attu, Heterop-neustes fossilis; amphibia e.g., Rana tigrina, Rana cyanophlyctis, <span class="hlt">Bufo</span> melanostictus; reptiles e.g. Varanus bengalensis, Uromastix hardwickii; birds e.g. Columba livia, Gallus domesticus, Passer domestica, Anas platyrhynchos; and mammals e.g. Homo sapiens, Mus musculus, Lepus cuniculus have been described. The mobility of proteins of blood sera has been studied over cellulose acetate paper and then a comparative pattern analysed</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1976-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">372</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://www.aes.bioflux.com.ro/docs/2010.2.113-119.pdf"> <span id="translatedtitle">Distribution of molluscan fauna in the Karangad estuarine mangroves, South East Coast of India</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.doaj.org/doaj?func=searchArticles">Directory of Open Access Journals (Sweden)</a></p> <p class="result-summary">Full Text Available A survey has been made during February 2010 to know the pattern of molluscan fauna inthe mangroves located along the Karangad estuary. During the present investigation in the researcharea, 25 species of molluscs were recorded. They belong to 14 genera, 10 families and 5 orders. Inthe study area, 13 species of gastropods namely, Cerithidea fluviatilis, Terebralia palustris, Cerithiumcitrinum, C. scabridum, C. obeliscus, Littorina scabra, L. undulata, Planaxis sulcatus, Drupamargariticola, D. heptagonalis, Thais rudolphi, T. <span class="hlt">bufo</span>, and T. tissoti and 12 species of bivalves –Gafrarium tumidum, G. pectinatum, Crassostrea madrasensis, Mactra cuneata, Tellina ala, T. bruguieri,Saccostrea cucculata, Modiolus metcalfei, M. tulipa, M. traillii, Meretrix meretrix and M. casta - wererecorded.</p> <div class="credits"> <p class="dwt_author">Santhanam Rajagopal</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">373</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=https://beta.openaire.eu/index.php?option=com_openaire&view=article&Itemid=114&articleId=doajarticles::05cd30a60b5532410f5b8fc263152c01"> <span id="translatedtitle">Synergistic Effects of Copper and Butylic Ester of 2,4-Dichlorophenoxyacetic Acid (Esternon Ultra) on Amphibian Embryos</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://search1.driver.research-infrastructures.eu/webInterface/simpleSearch.do?action=load">Digital Repository Infrastructure Vision for European Research (DRIVER)</a></p> <p class="result-summary">Cu2+ and butylic ester of 2,4-Dichlorophenoxyacetic acid as Esternon Ultra (2,4-D) toxicity on <span class="hlt">Bufo</span> arenarum embryos were evaluated by means of a short-term chronic toxicity test (AMPHITOX). The NOEC values for Cu and 2,4-D were 0.02 mg/L and 2 mg/L respectively. The toxicity profile curves for Cu and 2,4-D were reported. The interactions of the metal and the herbicide were evaluated by combined treatments with different concentrations of Cu and 2,4-D. Although in all cases, a synergistic eff...</p> <div class="credits"> <p class="dwt_author">Cristina Silvia Pérez-Coll; Jorge Herkovits</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">374</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://www.aha.org.ar/es/cuadherpetol/caracterizacion-morfologica-de-larvas-de-anuros-del-noroeste-argentino.pdf++"> <span id="translatedtitle">Caracterización morfológica de larvas de anuros del Noroeste argentino</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.doaj.org/doaj?func=searchArticles">Directory of Open Access Journals (Sweden)</a></p> <p class="result-summary">Full Text Available Se analizan caracteres morfológicos en larvas de catorce especies de anuros. Las especies analizadas son <span class="hlt">Bufo</span> arenarum, B. paracnemis, Leptodadylus chaquensis, L. latinasus, Odontophrynus americanus, O. lavillai, Phrynohyas venulosa, Phyllomedusa sauvagii, Physalaemus biligonigerus, P. cuqui, Pleurodema borellii, P. tucumana, Scinax fuscovaria y S. nasica. Estas especies se desarrollan en charcas temporarias del Noroeste de Argentina. Se caracterizan las larvas de cada especie por el análisis de la morfología externa e interna, caracteres de la cavidad oral, condrocráneo y arcos viscerales. Algunos de estos aspectos morfológicos se discuten con las hipótesis propuestas acerca de larvas generalizadas. We have analyzed morphological characters in tadpoles of fourteen anuran species. The species considered are <span class="hlt">Bufo</span> arenaum, B. paracnemis, Leptodactylus chaquensis, L. latinasus, Odontopbynus americanus, O.lavillai, Phrynohyas venulosa, Phyllomedusa sauvagii, Physalaemus biligonigerus, P. cuqui, Pleurodema borellii, P. tucumana, Scinax fuscovaria and S. nasica. They develop in similar temporary ponds of Northwestern of Argentina. We characterized the larvae of each species by the analyses on external morphology, internal oral features, chondrocranium and visceral archs. Some of these morphological aspects have been discussed with proposal hypotheses about generalized tadpoles.</p> <div class="credits"> <p class="dwt_author">Fabrezi, Marissa</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">375</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://www.redalyc.org/articulo.oa?id=80531103"> <span id="translatedtitle">Aprendizaje instrumental en anfibios</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.doaj.org/doaj?func=searchArticles">Directory of Open Access Journals (Sweden)</a></p> <p class="result-summary">Full Text Available Este trabajo presenta una revisión de los estudios realizados acerca de los mecanismos de aprendizaje en anfibios. Se conoce muy poco acerca de los procesos de aprendizaje en anfibios, y aún menos respecto de las relaciones cerebro-aprendizaje. Recientemente hemos comenzado el estudio sistemático del aprendizaje instrumental en el sapo <span class="hlt">Bufo</span> arenarum dentro de un marco comparativo. Se observaron diversos fenómenos de aprendizaje comunes a una amplia variedad de vertebrados, tales como la adquisición bajo condiciones de entrenamiento masivo y espaciado, la extinción, la recuperación espontánea, el efecto subsiguiente al refuerzo, y el efecto en al adquisición de la magnitud del reforzamiento. Además, comenzamos el análisis de los efectos sobre el aprendizaje de las lesiones del pallium medial (estructura postulada como homóloga al hipocampo de los mamíferos. La lesión del paIlium medial no tuvo efectos sobre el desempeño ni sobre la tasa de captación de agua durante la adquisición. Pero retardó significativamente la extinción de la respuesta instrumental en un corredor recto. Estos datos sugieren que el palli um medial de los sapos juega un papel en la inhibición de respuestas previamente aprendidas. Los resultados de nuestros estudios en el sapo <span class="hlt">Bufo</span> arenarum aportan datos origi na1es a la limitada información disponible sobre aprendizaje en anfibios.</p> <div class="credits"> <p class="dwt_author">Rubén N. Muzio</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">376</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://inis.iaea.org/search/search.aspx?orig_q=RN:36088395"> <span id="translatedtitle">Deriving freshwater quality criteria for 2,4-dichlorophenol for protection of aquatic life in China</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://inis.iaea.org/search/">International Nuclear Information System (INIS)</a></p> <p class="result-summary">Criteria were established for an organic pollutant in freshwaters of China. - Freshwater quality criteria for 2,4-dichlorophenol (2,4-DCP) were developed with particular reference to the aquatic biota in China, and based on USEPA's guidelines. Acute toxicity tests were performed on nine different domestic species indigenous to China to determine 48-h LC50 and 96-h LC50 values for 2,4-DCP. In addition, 21 day survival-reproduction tests with Daphnia magna, 30-day embryo-larval tests with Carassius auratus, 60 day fry-juvenile test with Ctenopharyngodon idellus, 30 d early life stage tests with <span class="hlt">Bufo</span> <span class="hlt">bufo</span> gargarizans and 96 h growth inhibition tests with Scenedesms obliqaus were conducted, to estimate lower chronic limit (LCL) and upper chronic limit (UCL) values. The final acute value (FAV) was 2.49 mg/l 2,4-DCP. Acute-to-chronic ratios (ACR) ranged from 3.74 to 22.5. The final chronic value (FCV) and the final plant value (FPV) of 2.4-DCP were 0.212 mg/l and 7.07 mg/l respectively. Based on FAV, FCV, and FPV, a criteria maximum concentration (CMC) of 1.25 mg/l and a criterion continuous concentration (CCC) of 0.212 mg/l were derived. The results of this study provide useful data for deriving national or local water quality criteria for 2,4-DCP based on aquatic biota in China</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2003-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">377</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24814996"> <span id="translatedtitle">Efficient purification of active bufadienolides by a class separation method based on hydrophilic solid-phase extraction and reversed-phase high performance liquid chromatography.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.science.gov/">Science.gov (United States)</a></p> <p class="result-summary">Traditional Chinese medicines (TCMs) have played a significant role in the process of discovering natural bioactive compounds, especially in anticancer therapeutics. However, the components of TCMs are complex mixtures with wide variation in polarity and content, which leads to inefficiency in the process of active compound discovery from TCMs. In this paper, the popular strategy of utilizing "pre-fractionated natural product libraries" has been improved by a new class separation approach to accelerate the process. As an example, the skin of <span class="hlt">Bufo</span> <span class="hlt">bufo</span> gargarizans Cantor, a well-known TCM, mainly contains two distinct bufadienolide classes: amino acid-conjugated bufadienolides (AACBs) and free form bufadienolides (AAUBs). We utilized hydrophilic interaction liquid chromatography solid-phase extraction (HILIC-SPE) to resolve the two types of bufadienolides, which co-eluted on C18 columns. By this strategy, twelve bufadienolides of the two types were purified via prep-HPLC from one active fraction, and eight of them were identified by (1)H NMR and (13)C NMR. These results indicated that the class separation method not only overcame the limited orthogonality in a 2D-RPLC×RPLC system but also accelerated the process of active compound discovery. PMID:24814996</p> <div class="credits"> <p class="dwt_author">Li, Xiaolong; Liu, Yanfang; Shen, Aijin; Wang, Chaoran; Yan, Jingyu; Zhao, Weijie; Liang, Xinmiao</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">378</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://www.revistas.unal.edu.co/index.php/cal/article/view/34432"> <span id="translatedtitle">Una nueva especie colombiana de Atelopus (Amphibia: Bufonidae Una nueva especie colombiana de Atelopus (Amphibia: Bufonidae</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.doaj.org/doaj?func=searchArticles">Directory of Open Access Journals (Sweden)</a></p> <p class="result-summary">Full Text Available Se describe una nueva especie del género Atelopus (loc. typ.: Río Carauta, Parque Nacional Natural de las Orquídeas, vertiente occidental de la Cordillera Occidental, Departamento de Antioquia, Colombia, distinguible de sus congéneres principalmente por su elongación rostral con el complejo esfenoetmoidal osificado y muy alargado, la ausencia de tímpano y de la columella auris, y la notable exóstosis de las crestas supratimpánicas y de las espinas neurales de las vértebras presacras. Por el desarrollo del rostro, la ausencia de tímpano y de columella auris y sus caracteres cromáticos exhibe un notable paralelismo evolutivo con las especies del género Rhamphophryne. También la exóstosis craneal y vertebral hallada, indican paralelismo evolutivo con <span class="hlt">Bufo</span> typhonius y con las especies del género Hemiphractus.A new species of Atelopus is described (loc. typ.: Río Carauta, Parque Nacional Natural de las Orquídeas, western slope of the Western Andes, Dept. of Antioquia, Colombia , it is recognizable among the remaining species of the genus mainly by the strikingly protruding snout, the ossification and elongation of the sphenoethmoidal complex, the absence of tympanum and columella auris, and the remarkable exostosis development of the supratympanic crests and the neural spines of the presacral vertebrae. The rostral development, the absence of tympanum and columella auris, and the chromatic characters reveal a noticeable evolutionary parallelism with the species of the genus Rhamphophryne. Also the cranial and vertebral exostosis found indicate a parallelism with <span class="hlt">Bufo</span> typhonius and the species of the genus Hemiphractus.</p> <div class="credits"> <p class="dwt_author">Ruíz Carranza Pedro M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1978-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">379</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://worldwidescience.org/wws/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUSMNB14A..05L"> <span id="translatedtitle">Tadpoles of Early Breeding Amphibians are Negatively Affected by Leaf Litter From Invasive Chinese Tallow Trees</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.science.gov/">Science.gov (United States)</a></p> <p class="result-summary">As wetlands are invaded by Chinese tallow trees (Triadica sebifera), native trees are displaced and detrital inputs to amphibian breeding ponds are altered. I used a mesocosm experiment to examine the effect of Chinese tallow leaf litter on the survival to, size at, and time to metamorphosis of amphibian larvae. Fifty 1000-L cattle watering tanks were treated with 1500 g dry weight of one of five leaf litter trea