WorldWideScience
 
 
1

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

UK PubMed Central (United Kingdom)

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

Franz KW; Romanowski J; Johst K; Grimm V

2013-01-01

2

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

Directory of Open Access Journals (Sweden)

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

T. Stephan; K. Ulbrich; W.-R. Grosse; F. Meyer

2001-01-01

3

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

DEFF Research Database (Denmark)

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

Allentoft, Morten E.; Siegismund, Hans Redlef

2009-01-01

4

Thyroid anatomy and topography of toad (Bufo marinus ictericus)  

International Nuclear Information System (INIS)

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

1970-01-01

5

Monitoring Arroyo Toads (Bufo californicus) in the San Bernardino National Forest, 2004. Annual Report.  

Science.gov (United States)

The arroyo toad (Bufo californicus) is endemic to southern California. This nocturnal toad is a habitat specialist preferring low gradient perennial or intermittent streams with sandy banks, gravel / sand bars, and sandy terraces. Urban development and ri...

A. R. Backlin C. J. Hitchcock R. N. Fisher

2004-01-01

6

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

7

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

Directory of Open Access Journals (Sweden)

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.

Moyano-Salvago, Mª Rosario; Molina-López, Ana Mª; Lora-Benítez, Antonio J; Rufino Moya, Pablo J;; Fernández-Palacios, O´Connor, Rocío; Camacho-Sillero, Leonor N

2009-01-01

8

Post-Cedar Fire Arroyo Toad ('Bufo californicus') Monitoring Surveys at Cuyamaca Rancho State Park, 2004.  

Science.gov (United States)

From 2002 to 2004, California State Parks contracted with the U.S. Geological Survey to conduct daytime habitat evaluation and focused nocturnal surveys to determine the distribution of suitable habitat and presence of arroyo toads (Bufo californicus) wit...

M. B. Mendelsohn M. C. Madden-Smith R. N. Fisher

2005-01-01

9

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

Directory of Open Access Journals (Sweden)

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

Isioma Tongo; Lawrence Ezemonye; Uche Ochei

2012-01-01

10

Accumulation and depuration of trace metals in Southern Toads, Bufo Terrestris, exposed to coal combustion waste  

Energy Technology Data Exchange (ETDEWEB)

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

Ward, C.; Hassan, S.; Mendonca, M. [Auburn University, Auburn, AL (United States). Dept. of Biological Science

2009-02-15

11

Altitudinal distribution and blood values in the toad, Bufo spinulosus Wiegmann.  

UK PubMed Central (United Kingdom)

1. Red blood cell (RBC) count, RBC size, hematocrit, cell and blood hemoglobin concentrations and plasma total solid concentration were measured in 16 lowland (from near sea level up to 2700 m) and 18 highland (3200 up to close to 4500 m) adult toads (Bufo spinulosus). 2. Lowland toads showed higher hematocrit values than highland toads, but their blood hemoglobin concentration and plasma solid concentration were not significantly different. 3. Highland toads had smaller RBC size, higher corpuscular hemoglobin concentration, a trend toward larger RBC count and a considerably smaller body size. These features may contribute to their successful life at high altitude.

Ruiz G; Rosenmann M; Veloso A

1989-01-01

12

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

Directory of Open Access Journals (Sweden)

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.

X. Santos; G. A. Llorente; A. Montori; M. A. Carretero; N. Franch; N. Garriga; A. Richter–Boix

2007-01-01

13

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

Science.gov (United States)

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

14

ADRENALIN AND HYDROXYTYRAMINE IN THE PAROTID GLAND VENOM OF THE TOAD, BUFO MARINUS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Preparations from the parotid gland venom of the toad Bufo marinus have been analyzed by paper chromatography for the presence of adrenalin precursors. In addition to adrenalin itself, hydroxytyramine was identified and a second compound which appeared to be an adrenalin ester—perhaps lactyl-adrena...

Gregerman, Robert I.

15

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

Directory of Open Access Journals (Sweden)

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

EVELYN L. BULL

2006-01-01

16

[Specific features of the melanophore system in different color morphs of larvae of the common toad (Bufo bufo L.)].  

UK PubMed Central (United Kingdom)

In a natural pond among usual black larvae of the common toad (Bufo bufo L.), a few unusual individuals of red-olive coloring were found out. In both morphs we investigated the melanophores of skin using different methods. The ESR-spectrometric analysis has shown the absence of distinctions between morphs by the amount of melanin. Analysis of total preparations of skin has shown the presence of various kinds of melanophore cells both in the derma and in the epidermis. Among typical melanophores, essentially differing cells appeared (atypical cells). In black morph tadpoles, the number of all kinds of melanophores is significantly greater than in red-olive morphs. It is shown that dark coloring is connected with a considerable number of atypical cells in the epidermis imposed on a dense layer of typical dermal melanophores with dispersed melanin.

Zakharova LA; Surova GS; Timofeev KN

2012-07-01

17

The ecological impact of invasive cane toads (Bufo marinus) in Australia.  

UK PubMed Central (United Kingdom)

Although invasive species are viewed as major threats to ecosystems worldwide, few such species have been studied in enough detail to identify the pathways, magnitudes, and timescales of their impact on native fauna. One of the most intensively studied invasive taxa in this respect is the cane toad (Bufo marinus), which was introduced to Australia in 1935. A review of these studies suggests that a single pathway-lethal toxic ingestion of toads by frog-eating predators-is the major mechanism of impact, but that the magnitude of impact varies dramatically among predator taxa, as well as through space and time. Populations of large predators (e.g., varanid and scincid lizards, elapid snakes, freshwater crocodiles, and dasyurid marsupials) may be imperilled by toad invasion, but impacts vary spatially even within the same predator species. Some of the taxa severely impacted by toad invasion recover within a few decades, via aversion learning and longer-term adaptive changes. No native species have gone extinct as a result of toad invasion, and many native taxa widely imagined to be at risk are not affected, largely as a result of their physiological ability to tolerate toad toxins (e.g., as found in many birds and rodents), as well as the reluctance of many native anuran-eating predators to consume toads, either innately or as a learned response. Indirect effects of cane toads as mediated through trophic webs are likely as important as direct effects, but they are more difficult to study. Overall, some Australian native species (mostly large predators) have declined due to cane toads; others, especially species formerly consumed by those predators, have benefited. For yet others, effects have been minor or have been mediated indirectly rather than through direct interactions with the invasive toads. Factors that increase a predator's vulnerability to toad invasion include habitat overlap with toads, anurophagy, large body size, inability to develop rapid behavioral aversion to toads as prey items, and physiological vulnerability to bufotoxins as a result of a lack of coevolutionary history of exposure to other bufonid taxa.

Shine R

2010-09-01

18

Plasma aldosterone, angiotensin II, and arginine vasotocin concentrations in the toad, Bufo marinus, following osmotic treatments.  

UK PubMed Central (United Kingdom)

To clarify the physiological roles of the renin-angiotensin-aldosterone system (RAAS) and arginine vasotocin (AVT) on body fluid regulation in amphibians, we measured plasma concentrations of aldosterone (ALDO), angiotensin II (ANG II), and AVT after various osmotic challenges in the marine toad, Bufo marinus (Bufonidae). Hematocrit value (Ht) as an indicator of plasma volume, plasma osmolality and concentrations of plasma components (Na(+), Cl(-), K(+), and urea) were also measured. The toads were maintained under various osmotic treatments for 7 days. In dehydrated toads, plasma concentrations of ALDO, ANG II, AVT, and all plasma components measured were increased. In toads maintained in 300 mosmol/kg H(2)O NaCl solution, plasma osmolality, Na(+), Cl(-), urea, and plasma AVT concentrations were significantly increased, and Ht and plasma concentrations of ALDO and ANG II were significantly decreased. In toads maintained in tap water, plasma osmolality, and concentrations of Na(+) and ALDO were significantly decreased. We also estimated total body water (TBW), plasma volume (PV) using Evans Blue dye and Ht in the toads under various osmotic treatments. In dehydrated toads, TBW and PV were significantly decreased and Ht was significantly increased in comparison with those of control. In toads maintained in 300 mosmol/kg H(2)O NaCl solution, TBW and PV were significantly increased and Ht was significantly decreased in comparison with those of control. There was a significant negative correlation between Ht and PV or TBW. These results show that dehydration, which induces hypovolemic and hyperosmotic conditions, stimulates increases of plasma ALDO, ANG II, and AVT concentrations, while hypervolemic treatment induces decreases of plasma ALDO and ANG II concentrations. There were significant correlations between plasma osmolality and AVT concentration, between Ht and concentrations of RAAS hormones, and between plasma concentrations of ALDO and ANG II. These results suggest that volumetric and osmometric systems regulated by RAAS hormones and AVT are present in B. marinus.

Konno N; Hyodo S; Takei Y; Matsuda K; Uchiyama M

2005-01-01

19

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

Directory of Open Access Journals (Sweden)

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

S. A. Sakr; S. M. Hanafy

2002-01-01

20

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

Energy Technology Data Exchange (ETDEWEB)

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).

Takada, Koji; Itoh, Masanori; Nishio, Hiroshi; Ishii, Susumu (Waseda Univ., Tokyo (Japan))

1989-10-01

 
 
 
 
21

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

22

Differential effects of dietary protein on early life-history and morphological traits in natterjack toad (Epidalea calamita) tadpoles reared in captivity.  

UK PubMed Central (United Kingdom)

The production of high quality amphibian larvae through optimal diets is a critical component of amphibian conservation breeding programs. Larval period, survival, body weight and total length are frequently used as metrics of adequate nutrition. However, the effects of nutrition on tadpole and metamorph morphology are rarely tested in detail. In the present study, we analyzed the most common metrics and six other larval and post-metamorphic morphological traits in natterjack toads (Epidalea calamita) fed with three different commercial fish diets, varying in protein content (32.0%, 38.3%, and 46.2%). Our results suggest that early life-history (tadpole growth, development, and survival) and morphological traits of E. calamita tadpoles are differentially affected by the percentage of dietary protein. As protein content increased, tadpoles exhibited larger bodies along with shorter tail fins; however, with no significant differences in total length. Larval period was similar across treatments but mortality was lower in high-protein diet. At high-protein diets the metamorphs revealed significantly longer bodies, and wider heads and hind legs, but there was no significant difference in the average weight across all dietary treatments. Based on our results, feed containing 46.2% protein promotes growth, development and survival of E. calamita tadpoles better than either of the other two feeds tested. The use of other body measures beyond weight, tadpole total length, and snout-vent length in studies of amphibian nutrition in captivity may assist the selection of appropriate diets to optimize tadpole survival and metamorph fitness.

Martins FM; Oom Mdo M; Rebelo R; Rosa GM

2013-07-01

23

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

Energy Technology Data Exchange (ETDEWEB)

The role of lipid transfer proteins during plasma membrane biogenesis was explored. Developing amphibia embryos were used because during their growth an active plasma membrane biosynthesis occurs together with negligible mitochondrial and endoplasmic reticulum proliferation. Sonicated vesicles, containing /sup 14/C-labeled phospholipids and /sup 3/H-labeled triolein, as donor particles and cross-linked erythrocyte ghosts as acceptor particles were used to measure phospholipid transfer activities in unfertilized oocytes and in developing embryos of the toad Bufo arenarum. Phosphatidylcholine transfer activity in pH 5.1 supernatant of unfertilized oocytes was 8-fold higher than the activity found in female toad liver supernatant, but dropped steadily 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.

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

1987-01-01

24

Factors influencing responses to alarm pheromone by larvae of invasive cane toads, Bufo marinus.  

UK PubMed Central (United Kingdom)

If pheromonal communication systems of invasive species differ from those of native biota, it may be possible to control the invader by exploiting that difference. When injured, the larvae of cane toads, Bufo marinus, an invasive species of major concern in tropical Australia, produce species-specific chemical cues that alert conspecific tadpoles to danger. Repeated exposure to the alarm chemical reduces tadpole survival rates and body sizes at metamorphosis and, thus, could help control toad populations. To evaluate the feasibility of this approach, we need to know how the intensity of toad tadpole response to the alarm chemical is affected by factors such as water temperature, time of day, larval stage and feeding history, geographic origin of the tadpoles, and habituation. Information on these topics may enable us to optimize deployment, so that tadpoles encounter pheromone at the times and places that confer maximum effect. In our studies, tadpole density, nutritional state, larval stage, and geographic origin had little effect on the intensity of the alarm response, but tadpoles reacted most strongly in higher water temperatures and during daylight hours. Repeated, once-daily exposure to pheromone did not induce habituation, but repeated exposure at 15-min intervals did not elicit further responses after 2 h total exposure. The insensitivity of response to most factors tested means that the effectiveness of the pheromone as a control agent should be relatively robust.

Hagman M; Shine R

2009-02-01

25

Factors influencing responses to alarm pheromone by larvae of invasive cane toads, Bufo marinus.  

Science.gov (United States)

If pheromonal communication systems of invasive species differ from those of native biota, it may be possible to control the invader by exploiting that difference. When injured, the larvae of cane toads, Bufo marinus, an invasive species of major concern in tropical Australia, produce species-specific chemical cues that alert conspecific tadpoles to danger. Repeated exposure to the alarm chemical reduces tadpole survival rates and body sizes at metamorphosis and, thus, could help control toad populations. To evaluate the feasibility of this approach, we need to know how the intensity of toad tadpole response to the alarm chemical is affected by factors such as water temperature, time of day, larval stage and feeding history, geographic origin of the tadpoles, and habituation. Information on these topics may enable us to optimize deployment, so that tadpoles encounter pheromone at the times and places that confer maximum effect. In our studies, tadpole density, nutritional state, larval stage, and geographic origin had little effect on the intensity of the alarm response, but tadpoles reacted most strongly in higher water temperatures and during daylight hours. Repeated, once-daily exposure to pheromone did not induce habituation, but repeated exposure at 15-min intervals did not elicit further responses after 2 h total exposure. The insensitivity of response to most factors tested means that the effectiveness of the pheromone as a control agent should be relatively robust. PMID:19184225

Hagman, Mattias; Shine, Richard

2009-01-30

26

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

Directory of Open Access Journals (Sweden)

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-Fluorophenyl)butyl]-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.

Browne Robert K; Li Hong; Seratt Jessica; Kouba Andrew

2006-01-01

27

Active transport of calcium across the urinary bladder and colon of the toad Bufo marinus.  

UK PubMed Central (United Kingdom)

Unidirectional fluxes of calcium were measured (in vitro) across the urinary bladder and colon of the toad Bufo marinus in the absence of electrochemical gradients. A net calcium flux was observed in each tissue, but the polarity differed; it occurred from the mucosal (luminal) to the serosal side of the colon and from the serosal to mucosal (urinary) side of the bladder. The active transport in each tissue appeared to involve different mechanisms; that across the colon exhibited a sodium dependence, possibly involving a sodium-calcium exchange, but this was not seen in the urinary bladder. The net flux in the latter was, however, abolished by metabolic inhibitors, possibly reflecting a role of a calcium-adenosine triphosphatase mechanism. The results are discussed in relation to the calcium metabolism of this amphibian.

Rosoff CJ; Baldwin GF; Bentley PJ

1983-07-01

28

The dynamics of venous return and response to hypervolemia in the toad, Bufo marinus (L.)  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Venous return from the posterior region of amphibians travels by either two renal portal veins to the kidney or a central abdominal vein that drains into the hepatic portal system. The relative proportions of blood flow in these vessels has never been measured nor has a modification of flow been determined when venous return increases by changes in blood volume during hypervolemia or during increased volume input from the posterior lymph hearts. Results Venous return from the posterior region of Bufo marinus was measured under resting conditions and in response to a systemic hypervolemia. Doppler flow probes were positioned on the renal portal and ventral abdominal veins, and flow was recorded as injections of artificial plasma equaling 100% of the animal's plasma volume were administered through the sciatic artery. Resting flow was found to be 5.54 ± 2.03 ml min-1 kg-1 in the paired renal portal veins, and 7.31 ± 0.89 ml min-1 kg-1 in the ventral abdominal vein. While renal portal flow was found to increase by a factor of 2.4 times during the first 10 min of hypervolemia, ventral abdominal flow only increased by a factor of 1.3. Conclusions Our results quantify the contribution to circulation from posterior venous return in the toad Bufo marinus. A preferential movement of excess fluid through the renal portal pathway was also demonstrated, supporting the possibility of water elimination via the renal portal circulation, especially during periods of high water influx into the animals.

Killorn Erin E; Toews Daniel P

2001-01-01

29

Effects of exercise on plasma catecholamine levels in the toad, Bufo paracnemis: role of the adrenals and neural control.  

Science.gov (United States)

Resting plasma epinephrine (E) and norepinephrine (N) concentrations for intact toads (Bufo paracnemis) were 5.57+/-1.0 and 0.88+/-0.38 ng/ml, respectively. Exercise induced a significant increase in heart rate, blood pressure and plasma epinephrine (about 4.3 times), whereas norepinephrine remained unchanged. The resting [E]/[N] ratio was 6.3 and increased to 32.9 during exercise. Adrenal denervation did not alter the basal plasma catecholamine or norepinephrine levels after exercise, but prevented the increase in epinephrine during exercise, suggesting that in the intact toad this increase is due to adrenal secretion whereas resting norepinephrine may be liberated by extra-adrenal chromaffin tissues. This also suggests that the adrenal glands can release selectively the two catecholamines. The increases in heart rate and blood pressure in denervated toads were not significantly different from those of intact animals, suggesting that during exercise the sympathetic nerves play the main role in inducing cardiovascular responses. Spinal transection induced a significant increase in basal norepinephrine levels, which remained elevated after exercise. Since spinal toads are unable to perform spontaneous movements it is possible that this increase may be caused by this stressful condition. The increases in heart rate and blood pressure observed in spinal toads during exercise may be due to direct mechanical effects of venous return on the heart. PMID:15562451

Romero, Sonia Maria Brazil; Pereira, Aparecida Fim; Garófalo, Maria Antonieta Rissato; Hoffmann, Anette

2004-12-01

30

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

UK PubMed Central (United Kingdom)

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

Espinoza-Jiménez A; García-Prieto L; Osorio-Sarabia D; León-Règagnon V

2007-08-01

31

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

Science.gov (United States)

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

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

2007-08-01

32

Hemoglobin affinity for oxygen in three subspecies of toads (Bufo sp.) living at different altitudes  

Directory of Open Access Journals (Sweden)

Full Text Available Blood oxygen affinity and red blood cell properties were measured in three subspecies of genus Bufo: Bufo spinulosus limensis, collected at sea level and at an average day temperature of 20ºC; Bufo spinulosus trifolium, from 3100 m, average day temperature of 15ºC; and Bufo spinulosus flavolineatus, from 4100 m, average day temperature of 10ºC. Electrophoresis of the hemoglobin showed the same component in each of the three subspecies. At 20ºC the blood oxygen affinities (P50) showed small differences between Bufo spinulosus limensis and Bufo spinulosus trifolium, whereas the value for Bufo spinulosus flavolineatus was markedly lower. At 10ºC, the ambient temperature of Bufo spinulosus flavolineatus, the P50 was extremely low compared with the other two subspecies at their corresponding ambient temperatures

HRVOJ OSTOJIC; CARLOS MONGE-C; VERONICA CIFUENTES

2000-01-01

33

Two new species of Rhabdias (Nematoda: Rhabdiasidae) from the marine toad, Bufo marinus (L.) (Lissamphibia: Anura: Bufonidae), in Central America.  

Science.gov (United States)

Two new Rhabdias species are described from the lungs of the cane toad Bufo marinus (L.) from Costa Rica and Nicaragua. Rhabdias alabialis n. sp. differs from other known species of the genus by the remarkable morphology of its head end, i.e., the absence of lips or pseudolabia, the slitlike oral opening, and the triangular shape of the buccal capsule in apical view. Rhabdias pseudosphaerocephala n. sp. is identified as a form previously known in Central and South America as Rhabdias sphaerocephala Goodey, 1924, a species initially described from toads in Europe. The new species is differentiated from R. sphaerocephala based on head-end morphology and sequences of nuclear rDNA. PMID:17436957

Kuzmin, Yuriy; Tkach, Vasyl V; Brooks, Daniel R

2007-02-01

34

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

2012-10-05

35

Prevalence of Salmonella spp. in Cane Toads (Bufo marinus) from Grenada, West Indies, and their Antimicrobial Susceptibility.  

UK PubMed Central (United Kingdom)

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.

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

2013-09-01

36

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

37

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

38

Effects of diazinon on larvae of the Asian common toad (Bufo melanostictus, Schneider 1799).  

Science.gov (United States)

Continuous subchronic exposure experiments were conducted to assess the effects of diazinon, an organophosphate pesticide, on the survival, growth and activity of larvae of the Asian common toad Bufo melanostictus. Two larval stages, the gill stage (Gosner stages 21 and 22) and gill-atrophy stage (Gosner stages 24 and 25), were continuously exposed to 4 microg/L, 400 mirog/L, and 10 mg/L of commercial-grade diazinon for 30 d. Treatments and untreated controls were maintained in triplicate with water changed and pesticide concentrations renewed every 3 d. Observations showed that subchronic exposure to 400 microg/L and 10 mg/L diazinon caused a significant dose-dependent increase in mortality compared to the control, regardless of the age at which larvae were exposed. One hundred percent mortality was observed in larvae exposed to 10 mg/L. No clear age-related sensitivity was evident in this study. The lethal concentrations at which 50% of the tadpoles (LC50) died during 30 d of continuous exposure were 6 and 7.5 mg/L for gill stage and gill-atrophy stage larvae, respectively. Diazinon impaired larval growth and activity. Tail abnormalities were apparent in larvae exposed to 400 microg/L and 10 mg/L of diazinon. This investigation provides the first empirical evidence of the negative effects of diazinon on the survival, growth and activity of B. melanostictus. The high degree of diazinon toxicity in this study highlights the need to consider important nontarget groups when recommending safe levels of pesticide application. PMID:18611080

Sumanadasa, Dulangi M; Wijesinghe, Mayuri R; Ratnasooriya, Wanigasekara D

2008-11-01

39

Effects of diazinon on larvae of the Asian common toad (Bufo melanostictus, Schneider 1799).  

UK PubMed Central (United Kingdom)

Continuous subchronic exposure experiments were conducted to assess the effects of diazinon, an organophosphate pesticide, on the survival, growth and activity of larvae of the Asian common toad Bufo melanostictus. Two larval stages, the gill stage (Gosner stages 21 and 22) and gill-atrophy stage (Gosner stages 24 and 25), were continuously exposed to 4 microg/L, 400 mirog/L, and 10 mg/L of commercial-grade diazinon for 30 d. Treatments and untreated controls were maintained in triplicate with water changed and pesticide concentrations renewed every 3 d. Observations showed that subchronic exposure to 400 microg/L and 10 mg/L diazinon caused a significant dose-dependent increase in mortality compared to the control, regardless of the age at which larvae were exposed. One hundred percent mortality was observed in larvae exposed to 10 mg/L. No clear age-related sensitivity was evident in this study. The lethal concentrations at which 50% of the tadpoles (LC50) died during 30 d of continuous exposure were 6 and 7.5 mg/L for gill stage and gill-atrophy stage larvae, respectively. Diazinon impaired larval growth and activity. Tail abnormalities were apparent in larvae exposed to 400 microg/L and 10 mg/L of diazinon. This investigation provides the first empirical evidence of the negative effects of diazinon on the survival, growth and activity of B. melanostictus. The high degree of diazinon toxicity in this study highlights the need to consider important nontarget groups when recommending safe levels of pesticide application.

Sumanadasa DM; Wijesinghe MR; Ratnasooriya WD

2008-11-01

40

Probabilistic secretion of quanta from nerve terminals in toad (Bufo marinus) muscle modulated by adenosine.  

UK PubMed Central (United Kingdom)

1. A study has been made of the effect of blocking endogenous adenosine on the statistics of quantal secretion at nerve terminals in toad (Bufo marinus) muscle during summer and winter. 2. Exogenous adenosine (10-50 microM) reduces the mean quantal content of the endplate potential (EPP) recorded with an intracellular microelectrode (m) by 36 +/- 6% (mean +/- S.E.M.), independent of the control value of m in both summer and winter. The variance of the EPP (S2) was reduced by adenosine in proportion to m, so that the probability of quantal secretion (p) remained relatively constant. 3. Exogenous adenosine reduces the mean quantal content of secretion recorded with an extracellular electrode (m(e)) to a similar extent (47 +/- 6%) at different relatively high secreting sites along nerve terminal branches in both summer and winter. 4. Both theophylline (20-100 microM) and adenosine deaminase (2.5 i.u./ml) increase the amplitude of the EPP in summer in a [Ca2+]o of 0.5 mM or greater; a maximum increase of about 40% is reached at a [Ca2+]o of 1.2 mM. The amplitude of the EPP in winter is usually reduced by theophylline in a [Ca2+]o of 0.5 mM, but is always increased in a [Ca2+]o greater than 0.9 mM to reach a maximum increase of about 40% at high [Ca2+]o. 5. The variance of the EPP (S2) was always increased by theophylline to a greater extent than m in summer, so that p decreased and Poisson rather than binomial statistics could be used to describe the distribution of EPP amplitudes. In winter, theophylline generally increased m and S2 to about the same extent, so that p did not change much. 6. An autocorrelation analysis of the amplitude of successive EPPs in a long train at 0.5 Hz in high [Ca2+]o showed that these are likely to be independently distributed. Adenosine secreted by one impulse is then unlikely to affect secretion by a subsequent impulse in the train. 7. These observations are discussed in terms of the hypothesis that endogenously secreted adenosine at a release site inhibits secretion by nearby release sites in summer; this has the effect of reducing m and to a greater extent S2 so that binomial rather than Poisson statistics can describe the frequency distribution of EPP amplitudes.

Bennett MR; Karunanithi S; Lavidis NA

1991-02-01

 
 
 
 
41

Hindlimb extensor muscle function during jumping and swimming in the toad (Bufo marinus).  

UK PubMed Central (United Kingdom)

Many anurans use their hindlimbs to generate propulsive forces during both jumping and swimming. To investigate the musculoskeletal dynamics and motor output underlying locomotion in such physically different environments, we examined patterns of muscle strain and activity using sonomicrometry and electromyography, respectively, during jumping and swimming in the toad Bufo marinus. We measured strain and electromyographic (EMG) activity in four hindlimb muscles: the semimembranosus, a hip extensor; the plantaris, an ankle extensor; and the gluteus and cruralis, two knee extensors. During jumping, these four muscles are activated approximately simultaneously; however, joint extension appears to be temporally staggered, with the hip beginning to extend prior to or initially faster than the more distal knee and ankle joints. Mirroring this pattern, the gluteus and plantaris shorten quite slowly and over a small distance during the first half of limb extension during take-off, before beginning to shorten rapidly. The hip and knee extensors finish shortening near the point of take-off (when the feet leave the ground), while the ankle-extending plantaris, which exhibits the longest-duration EMG burst, on average, always completes its shortening after take-off (mean 26 ms). During swimming, activation of the four muscles is also nearly synchronous at the start of a propulsive stroke. The onset of fascicle shortening is temporally staggered, with the knee extensors beginning to shorten first, prior to the hip and ankle extensors. In addition, the knee extensors also often exhibit some degree of slow passive shortening prior to the onset of EMG activity. The offset of muscle shortening during swimming is also staggered, and to a much greater extent than during jumping. During swimming, the cruralis and gluteus finish shortening first, the semimembranosus finishes 30-60 ms later, and the plantaris, which again exhibits the longest EMG burst, finishes shortening last (mean 150 ms after the cruralis). Interestingly, much of this extended shortening in the plantaris occurs at a relatively slow velocity and may reflect passive ankle extension caused by fluid forces, associated with previously generated unsteady (accelerative) limb movements, acting on the foot. Average EMG burst intensity tends to be greater during jumping than during swimming in all muscles but the gluteus. However, EMG burst duration only changes between jumping and swimming in the cruralis (duration during jumping is nearly twice as long as during swimming). The cruralis is also the only muscle to exhibit substantially greater fractional shortening during jumping (mean 0.28) than during swimming (mean 0.20 active strain, 0.22 total strain). On the basis of these results, it appears that toad hindlimb function is altered between jumping and swimming. Moreover, these functional differences are influenced by passive effects associated with physical differences between the external environments, but are also actively mediated by shifts in the motor output and mechanical behavior of several muscles.

Gillis GB; Biewener AA

2000-12-01

42

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

UK PubMed Central (United Kingdom)

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

Oromi N; Marquis O; Miaud C; Sanuy D

2008-01-01

43

Agricultural intensity in ovo affects growth, metamorphic development and sexual differentiation in the common toad (Bufo bufo).  

UK PubMed Central (United Kingdom)

Pollution was cited by the Global Amphibian Assessment to be the second most important cause of amphibian decline worldwide, however, the effects of the agricultural environment on amphibians are not well understood. In this study, spawn from Bufo bufo was taken from four sites in England and Wales with varying intensities of arable agriculture. Spawn was either placed in tanks containing aged tap water (ex-situ, five replicates) or in cages at the native site (caged, five replicates). Hatching success, abnormal tadpoles, and forelimb emergence were recorded during the larval stage. Individuals were also sampled at five time points (TP) during development (5-, 7-, 9-, 12-, 15-weeks post-hatch) and analysed for morphological parameters. The thyroids (TP2) and the gonads (TP3,4,5) were also analysed histologically. With the exception of the thyroid histopathology, all analysed endpoints were significantly different between ex-situ individuals reared under identical conditions from the different sites. In addition, intensity of arable agriculture had a negative effect on growth and development. At one site, despite distinct rearing conditions, a high level of intersex (up to 42%) and similar sex ratios were observed in both ex-situ and caged individuals. Taken together, these data suggest that maternal exposure and/or events in ovo had a much larger effect on growth, metamorphic development, and sexual differentiation in B. bufo than the ambient environment. This could have important implications for traditional exposure scenarios that typically begin at the larval stage. Intersex is reported for the first time in European amphibians in situ, highlighting the potential use of distinct populations of amphibians in fundamental research into the aetiology of specific developmental effects in wild amphibians.

Orton F; Routledge E

2011-06-01

44

Infection dynamics of the lungworm Rhabdias pseudosphaerocephala in its natural host, the cane toad (Bufo marinus), and in novel hosts (native Australian frogs).  

Science.gov (United States)

Host-parasite systems have often evolved over time, such that infection dynamics may become greatly modified from the time of initial contact of the host with the parasite. Biological invasions may be useful to clarify processes in the initial contact of hosts with parasites, and allow us to compare parasite uptake between the ancestral (coevolved) host and novel (noncoevolved) hosts. Cane toads (Bufo marinus) are spreading rapidly through tropical Australia, carrying with them a nematode lungworm (Rhabdias pseudosphaerocephala) congeneric with those found in Australian frogs. We investigated the dynamics of infections of the toad parasite by conducting histologic examinations of cane toads and three native Australian frogs (Litoria dahlii, Litoria nasuta, and Opisthodon ornatus) at 2, 6, and 10 days after experimental exposure to the toad lungworm. More worms were found in toads than in frogs, especially at longer periods postexposure. In toads, the infective larvae entered the skin and muscles within 2 days postexposure, passed into the coelom in 6 days, and reached the lungs at 10 days. In frogs, larvae were found in many organs rather than migrating to consistent target tissues; a few larvae reached the lungs of L. dahlii. Migratory larvae caused increasing inflammation (primarily granulomatous admixed with granulocytes then lymphocytes) through time, especially in frogs. Evolution has resulted in an enhanced ability of the lungworm to locate the target organ (the lungs) of the toad, and an increase in rates of parasite survival within this host. PMID:20966266

Pizzatto, Ligia; Shilton, Catherine M; Shine, Richard

2010-10-01

45

Anticancer Peptide fromChinese Toad (Bufo Bufo Gargarizans) Skin Enhanced Sensitivity to 5-Fu in Hepatocarcinoma cells (HepG2)  

Directory of Open Access Journals (Sweden)

Full Text Available OBJECTIVE To investigate the antiproliferative and apoptogenic activities of peptide extracted from the Chinese toad (Bufo bufogargarizans) skin (TSP) and its effects on hepatocarcinoma cell line.METHODS MTT assaywas used to detect the effects of TSP (50 mg/mL and 5 mg/mL) on the proliferation and viability of Hepatocarcinoma cell line (HepG2) and liver cell line (L-02); Flow cytometry was used in DNA content analysis to determine the cell distribution in different phases of cell cycle; Annexin V-FITC/PI stained fluorescence-activated cell sorter (FACS) and transmission electron microscope (TEM) were used to detect the apoptosis of the treated cells.RESULTS TSP could not suppress the proliferation and viability of normal liver L-02 cells, but strongly inhibited the proliferation and viability of HepG2 cells; TSP (50 mg/mL) primarily arrested the HepG2 cells at G1 phase of the cell cycle; TSP (50 mg/mL) induced apoptosis in HepG2 cells and enhanced the effects of 5-Fu.CONCLUSION TSP has potent antineoplastic activity against human hepatocarcinoma cells with little toxicity to normal liver cells and can enhance the effects of 5-Fu.

Chuang-xin LU; Wen-yu WANG; Ning MA; Yao CUI; Xiao-yan LI; Yun ZHOU

2011-01-01

46

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-12-01

47

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

Directory of Open Access Journals (Sweden)

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

Mesut Sahin; Erdal Balcan

2006-01-01

48

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

Directory of Open Access Journals (Sweden)

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; N. I. El-Desouki; A. E. Essawy

2001-01-01

49

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

International Nuclear Information System (INIS)

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

2009-01-01

50

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

Directory of Open Access Journals (Sweden)

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

M. SAKATE; P. C. LUCAS DE OLIVEIRA

2001-01-01

51

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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 gro (more) ups (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.

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

2001-12-01

52

Adaptation or exaptation? An experimental test of hypotheses on the origin of salinity tolerance in Bufo calamita.  

UK PubMed Central (United Kingdom)

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

Gomez-Mestre I; Tejedo M

2005-07-01

53

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

Directory of Open Access Journals (Sweden)

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; Liu-wang Nie; Ping-ping Zheng

2007-01-01

54

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)

[en] 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

2004-01-01

55

Ultrastructure of developmental stages of Hemolivia stellata (Apicomplexa: Haemogregarinidae) in the cane toad Bufo marinus and in its vector tick Amblyomma rotondatum.  

UK PubMed Central (United Kingdom)

The fine structure of the hemogregarine Hemolivia stellata Petit, Landau, Baccam and Lainson, 1990 developmental stages in the cane toad Bufo marinus L. and the vector tick Amblyomma rotondatum Koch, 1844 are described. In the liver of the toad, merozoites bound by a pellicle were located free and in the cytoplasm, and young and encased mature polynucleated meronts were located in a parasitophorous vacuole (PV). Premature gametocytes in the erythrocytes were bound by a bilayered membranous wall and the mature gametocytes were encased in a bivalved capsule, suture sites occurring at both gametocyte extremities. In the tick gut cells, oocysts located within a PV formed oblong, pellicle-bound sporokinetes, with a small apical complex, a few short rhoptries, and a fragmented crystalloid body. Liberated sporokinetes re-entered gut cells to proceed with their differentiation into sporocysts within a PV with elaborate rims which suggested engagement in active metabolite cross-transport. With maturity, the sporocyst wall gradually transformed into a hard capsule. Differences in fine structural development between species of Hemolivia and the insect-transmitted Hepatozoon are conspicuous. The fine structure and course of development of H. stellata are very similar to those of the previously described Hemolivia mariae; their sporokinetes differ, however, in having conspicuous rhoptries rather than spherical-granular anlagen bodies, and fragmented rather than continuous crystalline bodies.

Boulard Y; Paperna I; Petit G; Landau I

2001-08-01

56

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

International Nuclear Information System (INIS)

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

1997-01-01

57

Effect of an increase in environmental temperature on testicular androgenesis and spermatogenesis in toad (Bufo melanostictus) during hibernating season.  

UK PubMed Central (United Kingdom)

Activities of key testicular androgenic enzymes [?(5), 3?-hydroxysteroid dehydrogenase (?(5), 3?-HSD) and 17?-hydroxysteroid dehydrogenase (17?-HSD)], plasma levels of testosterone, and testicular gametogenic activities were studied in heat-exposed adult male toads during hibernating season for two consecutive years. Exposure of toads to an elevated environmental temperature for 14 and 21 days resulted in significant elevation of testicular ?(5), 3?-HSD and 17?-HSD activities, along with plasma levels of testosterone. Testicular gametogenic activity, by means of quantity of all stages of spermatogenic cycle, were elevated significantly at the same experimental schedule, but 7 days of heat exposure resulted in significant elevation only in stage IV. The results indicated that environmental temperature is an important modulator of breeding activities of male toads. It also demonstrated that testicular activities in seasonally breeding toads are probably not linked to hibernating cycle. Zoo Biol 29:1-8, 2010. © 2010 Wiley-Liss, Inc.

Parua ' Mondal ' S; Debnath JM; Ghosh D

2010-12-01

58

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-01-01

59

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

Directory of Open Access Journals (Sweden)

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

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

2003-01-01

60

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

Scientific Electronic Library Online (English)

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

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

2003-02-01

 
 
 
 
61

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

UK PubMed Central (United Kingdom)

BACKGROUND: One key question in evolutionary biology deals with the mode and rate at which reproductive isolation accumulates during allopatric speciation. Little is known about secondary contacts of recently diverged anuran species. Here we conduct a multi-locus field study to investigate a contact zone between two lineages of green toads with an estimated divergence time of 2.7 My, and report results from preliminary experimental crosses. RESULTS: The Sicilian endemic Bufo siculus and the Italian mainland-origin B. balearicus form a narrow hybrid zone east of Mt. Etna. Despite bidirectional mtDNA introgression over a ca. 40 km North-South cline, no F1 hybrids could be found, and nuclear genomes display almost no admixture. Populations from each side of the contact zone showed depressed genetic diversity and very strong differentiation (FST = 0.52). Preliminary experimental crosses point to a slightly reduced fitness in F1 hybrids, a strong hybrid breakdown in backcrossed offspring (F1 x parental, with very few reaching metamorphosis) and a complete and early mortality in F2 (F1 x F1). CONCLUSION: Genetic patterns at the contact zone are molded by drift and selection. Local effective sizes are reduced by the geography and history of the contact zone, B. balearicus populations being at the front wave of a recent expansion (late Pleistocene). Selection against hybrids likely results from intrinsic genomic causes (disruption of coadapted sets of genes in backcrosses and F2-hybrids), possibly reinforced by local adaptation (the ranges of the two taxa roughly coincide with the borders of semiarid and arid climates). The absence of F1 in the field might be due to premating isolation mechanisms. Our results, show that these lineages have evolved almost complete reproductive isolation after some 2.7 My of divergence, contrasting sharply with evidence from laboratory experiments that some anuran species may still produce viable F1 offspring after > 20 My of divergence.

Colliard C; Sicilia A; Turrisi GF; Arculeo M; Perrin N; Stöck M

2010-01-01

62

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

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background One key question in evolutionary biology deals with the mode and rate at which reproductive isolation accumulates during allopatric speciation. Little is known about secondary contacts of recently diverged anuran species. Here we conduct a multi-locus field study to investigate a contact zone between two lineages of green toads with an estimated divergence time of 2.7 My, and report results from preliminary experimental crosses. Results The Sicilian endemic Bufo siculus and the Italian mainland-origin B. balearicus form a narrow hybrid zone east of Mt. Etna. Despite bidirectional mtDNA introgression over a ca. 40 km North-South cline, no F1 hybrids could be found, and nuclear genomes display almost no admixture. Populations from each side of the contact zone showed depressed genetic diversity and very strong differentiation (FST = 0.52). Preliminary experimental crosses point to a slightly reduced fitness in F1 hybrids, a strong hybrid breakdown in backcrossed offspring (F1 x parental, with very few reaching metamorphosis) and a complete and early mortality in F2 (F1 x F1). Conclusion Genetic patterns at the contact zone are molded by drift and selection. Local effective sizes are reduced by the geography and history of the contact zone, B. balearicus populations being at the front wave of a recent expansion (late Pleistocene). Selection against hybrids likely results from intrinsic genomic causes (disruption of coadapted sets of genes in backcrosses and F2-hybrids), possibly reinforced by local adaptation (the ranges of the two taxa roughly coincide with the borders of semiarid and arid climates). The absence of F1 in the field might be due to premating isolation mechanisms. Our results, show that these lineages have evolved almost complete reproductive isolation after some 2.7 My of divergence, contrasting sharply with evidence from laboratory experiments that some anuran species may still produce viable F1 offspring after > 20 My of divergence.

Colliard Caroline; Sicilia Alessandra; Turrisi Giuseppe; Arculeo Marco; Perrin Nicolas; Stöck Matthias

2010-01-01

63

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

Scientific Electronic Library Online (English)

Full Text Available 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 lectinas, tendo sido utilizadas 8 lectinas com diferentes especificidades para carboidratos (Ulex europaeus (UEA I), Lens culinaris (LCA), Erythrina cristagalli (ECA), Ara (more) chis 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 carbohydrate specificities: Ulex europaeus (UEA I), Lens culinaris (LCA), Erythrina cristagalli (ECA), Arachis hypogaea (PNA), Ricinus communis (RCA I), Aleuria aurantia (AAA), Tr (more) iticum 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.

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

2006-02-01

64

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

Directory of Open Access Journals (Sweden)

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

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

2006-01-01

65

Oxygen Transport in Amphibia: The Functional Properties of Hemoglobins from Bufo bufo and Bufo viridis  

Directory of Open Access Journals (Sweden)

Full Text Available The oxygen binding properties of the hemoglobins from two toads, Bufo bufo and Bufo viridis, have been investigated as a function of protons, chloride ions, organic phosphates and temperature. Electrophoretic analysis of the hemolysates showed the presence of a main hemoglobin in each of the two species. We found that the hemoglobin from Bufo bufo shows at 20°C a slight Bohr effect which tends to increase in the presence of the different allosteric effectors (chloride ions and ATP). At 37°C, the effect of protons is completely abolished in all experimental conditions. The Bufo viridis Hb presents a Bohr effect slightly more pronounced (doubled with respect to B. bufo) which increases only with the simultaneous presence of modulators, both at 20 and at 37°C. Moreover the overall heats of oxygenation (expressed by ?H values) result in the two amphibian hemoglobins much less exothermic than that of the human hemoglobin and in the case of Bufo viridis completely independent by organic phosphate (DPG). These particular features are very interesting because the two hemoglobins seem well adapted to the different habitats and physiological needs characterizing the two toads.

Maria Elisabetta Clementi; Francesco Misiti; Federica Orsini; Michela Pezzotti; Bruno Giardina

2007-01-01

66

Distribution and Status of the Arroyo Toad (Bufo californicus) and Western Pond Turtle (Emys marmorata) in the San Diego MSCP and Surrounding Areas.  

Science.gov (United States)

In 2002 and 2003 the U. S. Geological Survey conducted focused surveys for the arroyo toad and western pond turtle within nine watersheds of San Diego County, eight of which fall within the MSCP boundaries. Daytime arroyo toad habitat surveys were conduct...

E. L. Ervin K. P. Meyer M. C. Madden-Smith R. N. Fisher S. A. Hathaway

2005-01-01

67

How complex is the Bufo bufo species group?  

UK PubMed Central (United Kingdom)

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

Arntzen JW; Recuero E; Canestrelli D; Martínez-Solano I

2013-12-01

68

How complex is the Bufo bufo species group?  

Science.gov (United States)

Species delineation remains one of the most challenging tasks in the study of biodiversity, mostly owing to the application of different species concepts, which results in contrasting taxonomic arrangements. This has important practical consequences, since species are basic units in fields like ecology and conservation biology. We here review molecular genetic evidence relevant to the systematics of toads in the Bufo bufo species group (Anura, Bufonidae). Two studies recently published in this journal (Recuero et al., MPE 62: 71-86 and Garci?a-Porta et al., MPE 63: 113-130) addressed this issue but reached opposing conclusions on the taxonomy of the group (four versus two species). In particular, allozyme data in the latter paper were interpreted as evidence for hybridization across species (between B. bufo-B. spinosus and B. bufo-B. verrucosissimus). We tested claims for hybridization through re-analysis of allozyme data for individuals instead of populations, to be able to distinguish between sympatry with and without admixture, and found no evidence of hybridization across taxa. We propose alternative explanations for the observed patterns that Garci?a-Porta et al. (2012) failed to consider. In the absence of unequivocal evidence for hybridization and introgression, we reject the proposal to downgrade Bufo spinosus and Bufo verrucosissimus to the subspecies level. PMID:23880535

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

2013-07-20

69

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  

Directory of Open Access Journals (Sweden)

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; A.E. Essawy; M.H. Shwairebv; H.M. Abdel-Karim

2000-01-01

70

Low rates of X-Y recombination, not turnovers, account for homomorphic sex chromosomes in several diploid species of Palearctic green toads (Bufo viridis subgroup).  

UK PubMed Central (United Kingdom)

Contrasting with birds and mammals, most ectothermic vertebrates present homomorphic sex chromosomes, which might be due either to a high turnover rate or to occasional X-Y recombination. We tested these two hypotheses in a group of Palearctic green toads that diverged some 3.3 million years ago. Using sibship analyses of sex-linked markers, we show that all four species investigated share the same pair of sex chromosomes and a pattern of male heterogamety with drastically reduced X-Y recombination in males. Phylogenetic analyses of sex-linked sequences show that X and Y alleles cluster by species, not by gametolog. We conclude that X-Y homomorphy and fine-scale sequence similarity in these species do not stem from recent sex-chromosome turnovers, but from occasional X-Y recombination.

Stöck M; Savary R; Betto-Colliard C; Biollay S; Jourdan-Pineau H; Perrin N

2013-03-01

71

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

72

Embryotoxicity of lead on Bufo arenarum  

Energy Technology Data Exchange (ETDEWEB)

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

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

1988-08-01

73

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

UK PubMed Central (United Kingdom)

The notorious “cane toad” (Bufo marinus) is considered to be one of the 100 worst invasive species in the world. A native of South and Central America, Mexico, and the Rio Grande Valley of the United States, this large toad was intentionally introduced to islands in the Caribbean, and subsequently throughout the southern Pacific, as a biological control agent to combat sugar cane pests. Unfortunately, the primary result of those introductions has been deleterious impacts on native biotas, primarily through competition and predation. More recently, the cane toad has devastated populations of amphibian-eating predators in Australia, through the ingestion of this highly toxic anuran. Elsewhere, however, the impact of the toad on native predators has not been documented. Here we report the first evidence that the cane toad is impacting native predators in other geographic regions. Specifically, we document death due to cane toad poisoning in the endemic and threatened Jamaican boa (Epicrates subflavus). To our knowledge, this is the first report of cane toads causing mortality in naturally occurring predators outside of Australia. Like all members of the genus, B. marinus secretes a powerful bufogenin toxin, which is often fatal if ingested by naïve species that have not co-evolved with Bufo species. Our results should therefore serve as a warning that other endemic predator species in the West Indies and elsewhere may be at risk. Thus, efforts to control the population growth and spread of cane toads may be of even greater conservation concern than previously recognized.

Wilson ByronS; Koenig SusanE; van Veen Rick; Miersma Erika; Craig Rudolph D

2011-01-01

74

Impact of Invasive Cane Toads on Australian Birds  

UK PubMed Central (United Kingdom)

The cane toad (Bufo marinus), a large, toxic, American anuran, was introduced to Australia in 1935. Populations of many of Australia's reptiles (snakes, varanid lizards, crocodiles) and carnivorous mammals (dasyurid marsupials) have declined because these predators are killed by the toad's powerful toxins. In contrast to these well-studied species, little is known about the cane toads impacts on Australian birds. We reviewed published and unpublished data on behavioral interactions between Australian avian predators and cane toads and collated distributional and dietary information to identify avian taxa potentially at risk from cane toad invasion. Cane toads are sympatric with 172 frog-eating bird species in Australia, and an additional 8 bird species overlap with the predicted future range of the toad. Although many bird species thus are potentially at risk, behavioral observations suggest the risk level is generally low. Despite occasional reports of Australian birds being killed when they ingest cane toads, most birds either ignore toads or survive the predation event. The apparently higher tolerance of Australian birds to toad toxins, compared with Australian reptiles and marsupials, may reflect genetic exchange between Australian birds and Asian populations that encounter other bufonid species regularly and hence have evolved the capacity to recognize or tolerate this toxic prey.

BECKMANN CHRISTA; SHINE RICHARD

2009-12-01

75

Impact of invasive cane toads on Australian birds.  

UK PubMed Central (United Kingdom)

The cane toad (Bufo marinus), a large, toxic, American anuran, was introduced to Australia in 1935. Populations of many of Australia's reptiles (snakes, varanid lizards, crocodiles) and carnivorous mammals (dasyurid marsupials) have declined because these predators are killed by the toad's powerful toxins. In contrast to these well-studied species, little is known about the cane toads impacts on Australian birds. We reviewed published and unpublished data on behavioral interactions between Australian avian predators and cane toads and collated distributional and dietary information to identify avian taxa potentially at risk from cane toad invasion. Cane toads are sympatric with 172 frog-eating bird species in Australia, and an additional 8 bird species overlap with the predicted future range of the toad. Although many bird species thus are potentially at risk, behavioral observations suggest the risk level is generally low. Despite occasional reports of Australian birds being killed when they ingest cane toads, most birds either ignore toads or survive the predation event. The apparently higher tolerance of Australian birds to toad toxins, compared with Australian reptiles and marsupials, may reflect genetic exchange between Australian birds and Asian populations that encounter other bufonid species regularly and hence have evolved the capacity to recognize or tolerate this toxic prey.

Beckmann C; Shine R

2009-12-01

76

DIET OF THE SOUTHERN TOAD FROM THE SOUTHERN EVERGLADES  

Science.gov (United States)

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

77

Multilocus species tree analyses resolve the radiation of the widespread Bufo bufo species group (Anura, Bufonidae).  

UK PubMed Central (United Kingdom)

New analytical methods are improving our ability to reconstruct robust species trees from multilocus datasets, despite difficulties in phylogenetic reconstruction associated with recent, rapid divergence, incomplete lineage sorting and/or introgression. In this study, we applied these methods to resolve the radiation of toads in the Bufo bufo (Anura, Bufonidae) species group, ranging from the Iberian Peninsula and North Africa to Siberia, based on sequences from two mitochondrial and four nuclear DNA regions (3490 base pairs). We obtained a fully-resolved topology, with the recently described Bufo eichwaldi from the Talysh Mountains in south Azerbaijan and Iran as the sister taxon to a clade including: (1) north African, Iberian, and most French populations, referred herein to Bufo spinosus based on the implied inclusion of populations from its type locality and (2) a second clade, sister to B. spinosus, including two sister subclades: one with all samples of Bufo verrucosissimus from the Caucasus and another one with samples of B. bufo from northern France to Russia, including the Apennine and Balkan peninsulas and most of Anatolia. Coalescent-based estimations of time to most recent common ancestors for each species and selected subclades allowed historical reconstruction of the diversification of the species group in the context of Mediterranean paleogeography and indicated a long evolutionary history in this region. Finally, we used our data to delimit the ranges of the four species, particularly the more widespread and historically confused B. spinosus and B. bufo, and identify potential contact zones, some of which show striking parallels with other co-distributed species.

Recuero E; Canestrelli D; Vörös J; Szabó K; Poyarkov NA; Arntzen JW; Crnobrnja-Isailovic J; Kidov AA; Cog?lniceanu D; Caputo FP; Nascetti G; Martínez-Solano I

2012-01-01

78

Multilocus species tree analyses resolve the radiation of the widespread Bufo bufo species group (Anura, Bufonidae).  

Science.gov (United States)

New analytical methods are improving our ability to reconstruct robust species trees from multilocus datasets, despite difficulties in phylogenetic reconstruction associated with recent, rapid divergence, incomplete lineage sorting and/or introgression. In this study, we applied these methods to resolve the radiation of toads in the Bufo bufo (Anura, Bufonidae) species group, ranging from the Iberian Peninsula and North Africa to Siberia, based on sequences from two mitochondrial and four nuclear DNA regions (3490 base pairs). We obtained a fully-resolved topology, with the recently described Bufo eichwaldi from the Talysh Mountains in south Azerbaijan and Iran as the sister taxon to a clade including: (1) north African, Iberian, and most French populations, referred herein to Bufo spinosus based on the implied inclusion of populations from its type locality and (2) a second clade, sister to B. spinosus, including two sister subclades: one with all samples of Bufo verrucosissimus from the Caucasus and another one with samples of B. bufo from northern France to Russia, including the Apennine and Balkan peninsulas and most of Anatolia. Coalescent-based estimations of time to most recent common ancestors for each species and selected subclades allowed historical reconstruction of the diversification of the species group in the context of Mediterranean paleogeography and indicated a long evolutionary history in this region. Finally, we used our data to delimit the ranges of the four species, particularly the more widespread and historically confused B. spinosus and B. bufo, and identify potential contact zones, some of which show striking parallels with other co-distributed species. PMID:21964513

Recuero, E; Canestrelli, D; Vörös, J; Szabó, K; Poyarkov, N A; Arntzen, J W; Crnobrnja-Isailovic, J; Kidov, A A; Cog?lniceanu, D; Caputo, F P; Nascetti, G; Martínez-Solano, I

2011-09-22

79

Glutathione transferase activity during Bufo bufo development.  

Science.gov (United States)

High levels of glutathione transferase activity were measured during the development of the embryos of Bufo bufo including unfertilized eggs. After stage 4 glutathione transferase activity gradually decreased until stage 25 when the minimum was reached. No change in the number of isozymes was noted during development according to isoelectric focusing analysis performed on the cytosolic fractions of selected stages. PMID:3107890

Del Boccio, G; Di Ilio, C; Miranda, M; Manilla, A; Zarivi, O; Bonfigli, A; Federici, G

1987-01-01

80

Glutathione transferase activity during Bufo bufo development.  

UK PubMed Central (United Kingdom)

High levels of glutathione transferase activity were measured during the development of the embryos of Bufo bufo including unfertilized eggs. After stage 4 glutathione transferase activity gradually decreased until stage 25 when the minimum was reached. No change in the number of isozymes was noted during development according to isoelectric focusing analysis performed on the cytosolic fractions of selected stages.

Del Boccio G; Di Ilio C; Miranda M; Manilla A; Zarivi O; Bonfigli A; Federici G

1987-01-01

 
 
 
 
81

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

UK PubMed Central (United Kingdom)

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.

Bernabò I; Bonacci A; Coscarelli F; Tripepi M; Brunelli E

2013-05-01

82

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

Directory of Open Access Journals (Sweden)

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; Kamal S. Ghazaly; Amina E. Essawy; Atef M. Al-Attar

2002-01-01

83

Toad's tongue for breakfast: exploitation of a novel prey type, the invasive cane toad, by scavenging raptors in tropical Australia  

UK PubMed Central (United Kingdom)

Although interest in the ecological impacts of invasive species has largely focused on negative effects, some native taxa may benefit from invader arrival. In tropical Australia, invasive cane toads (Bufo marinus) have fatally poisoned many native predators (e.g., marsupials, crocodiles, lizards) that attempt to ingest the toxic anurans, but birds appear to be more resistant to toad toxins. We quantified offtake of dead (road-killed) cane toads by raptors (black kites (Milvus migrans) and whistling kites (Haliastur sphenurus)) at a site near Darwin, in the Australian wet-dry tropics. Raptors readily took dead toads, especially small ones, although native frogs were preferred to toads if available. More carcasses were removed in the dry season than the wet season, perhaps reflecting seasonal availability of alternative prey. Raptors appeared to recognize and avoid bufotoxins, and typically removed and consumed only the toads' tongues (thereby minimizing toxin uptake). The invasion of cane toads thus constitutes a novel prey type for scavenging raptors, rather than (as is the case for many other native predators) a threat to population viability.

Beckmann C; Shine R

2011-06-01

84

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

International Nuclear Information System (INIS)

Urea is actively transported inwardly (Ji) across the skin of the green toad Bufo viridis. Ji is markedly enhanced in toads adapted to hypertonic saline. The authors studied urea transport across the skin of Bufo viridis under a variety of experimental conditions, including treatment with amiloride and phloretin, agents that inhibit urea permeability in the bladder of Bufo marinus. Amiloride (10-4 M) significantly inhibited Ji in both adapted and unadapted animals and was unaffected by removal of sodium from the external medium. Phloretin (10-4 M) significantly inhibited Ji in adapted animals by 23-46%; there was also a reduction in Ji in unadapted toads at 10-4 and 5 x 10-4 M phloretin. A dose-response study revealed that the concentration of phloretin causing half-maximal inhibition (K1/2) was 5 x 10-4 M for adapted animals. Ji was unaffected by the substitution of sucrose for Ringer solution or by ouabain. They conclude (1) the process of adaptation appears to involve an increase in the number of amiloride- and phloretin-inhibitable urea transport sites in the skin, with a possible increase in the affinity of the sites for phloretin; (2) the adapted skin resembles the Bufo marinus urinary bladder with respect to amiloride and phloretin-inhibitable sites; (3) they confirm earlier observations that Ji is independent of sodium transport

1988-01-01

85

Effects of an Invasive Plant on Population Dynamics in Toads.  

UK PubMed Central (United Kingdom)

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

Greenberg DA; Green DM

2013-05-01

86

Toad envenoming in dogs: effects and treatment  

Directory of Open Access Journals (Sweden)

Full Text Available 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 their 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

2000-01-01

87

Toad envenoming in dogs: effects and treatment  

Scientific Electronic Library Online (English)

Full Text Available 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 their 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 gl (more) ands, 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.

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

2000-01-01

88

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

Energy Technology Data Exchange (ETDEWEB)

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

Bernabo, Ilaria [Department of Ecology, University of Calabria, Via P. Bucci, 87036 Rende (Cosenza) (Italy); Brunelli, Elvira [Department of Ecology, University of Calabria, Via P. Bucci, 87036 Rende (Cosenza) (Italy)], E-mail: brunelli@unical.it; Berg, Cecilia [Department of Environmental Toxicology, Uppsala University, Norbyvagen 18A, 752 36 Uppsala (Sweden); Bonacci, Antonella; Tripepi, Sandro [Department of Ecology, University of Calabria, Via P. Bucci, 87036 Rende (Cosenza) (Italy)

2008-02-18

89

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

International Nuclear Information System (INIS)

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

2008-02-18

90

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1988-09-01

91

Something different for dinner? Responses of a native Australian predator (the keelback snake) to an invasive prey species (the cane toad)  

UK PubMed Central (United Kingdom)

Predictions from foraging theory suggest that the probability a native predator will incorporate a novel type of prey (such as an invasive species) into its diet depends upon the potential benefits (e.g., nutrient input) vs. costs (e.g., handling time) of ingesting it. Cane toads (Bufo marinus) were introduced to Australia in 1935 and are highly toxic to many frog-eating snakes, thus there was strong selection to delete toads from the diet of these species. What has happened, however, to the feeding responses of an Australian snake species that is able to consume toads without dying? Our field surveys in northeastern Queensland show that, despite their high tolerance to toad toxins (compared to other native snakes), keelbacks (Tropidonophis mairii) feed primarily on native frogs rather than cane toads. This pattern occurs because the snakes show active prey preferences; even under standardized conditions in the laboratory, snakes are more likely to consume frogs than toads. When they are force-fed, snakes frequently regurgitate toads but not frogs. Thus, despite the high availability of the abundant toads, these invasive anurans are largely avoided as prey. This probably occurs because consumption of toads, although not lethal to keelbacks, causes significant sublethal effects and confers little nutritional benefit. Hence, keelback populations are not threatened by toad invasion, but neither do the snakes benefit substantially from the availability of a new type of potential prey.

Llewelyn John; Schwarzkopf Lin; Alford Ross; Shine Richard

2010-05-01

92

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

Science.gov (United States)

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

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

2010-01-01

93

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

UK PubMed Central (United Kingdom)

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

Landler L; Gollmann G

2011-01-01

94

Glutathione peroxidases and glutathione reductase activities during Bufo bufo development.  

UK PubMed Central (United Kingdom)

Glutathione peroxidases and glutathione reductase activities are expressed from the early stage of Bufo bufo development. Selenium-dependent and selenium-independent glutathione peroxidase activities fluctuated independently. The activity of selenium-independent was found to be higher than that of selenium-dependent glutathione peroxidase through all stages of development. Glutathione reductase activity, after a slight fall from stage 4 to stage 7, constantly increased up to stage 25.

Di Ilio C; Del Boccio G; Miranda M; Manilla A; Zarivi O; Federici G

1986-01-01

95

Glutathione peroxidases and glutathione reductase activities during Bufo bufo development.  

Science.gov (United States)

Glutathione peroxidases and glutathione reductase activities are expressed from the early stage of Bufo bufo development. Selenium-dependent and selenium-independent glutathione peroxidase activities fluctuated independently. The activity of selenium-independent was found to be higher than that of selenium-dependent glutathione peroxidase through all stages of development. Glutathione reductase activity, after a slight fall from stage 4 to stage 7, constantly increased up to stage 25. PMID:2869913

Di Ilio, C; Del Boccio, G; Miranda, M; Manilla, A; Zarivi, O; Federici, G

1986-01-01

96

Plasma potassium may protect sodium pumps of toad hearts from an endogenous inhibitor.  

UK PubMed Central (United Kingdom)

Resibufogenin (3-hydroxy-14,15-epoxy-20,22-dienolide glycoside) is a potent sodium pump inhibitor present in toad toxin. It is present in the skin of the cane toad (Bufo marinus) at a concentration equivalent to ouabain of approximately 1 mM. Because toads, like other amphibians, have permeable skin, resibufogenin is also found in high concentrations in the blood. In the cane toad the blood concentration is estimated to be 1 microM (D. Lichtstein, S. Kachalsky, and J. Deutsch. Life Sci. 38: 1261-1270, 1986; D. Lichtstein, S. Samuelov, J. Deutsch, H. Xu, R. A. Lutz, S. S. Chernick and S. S. Chernick. Klin. Wochenschr. 65, Suppl. 8: 40-48, 1987), a concentration thousands of times that required to produce toxicity in humans (J. S. Flier, E. Matatos-Flier, J. A. Pallotta, and D. McIsaac. Nature Lond. 279: 341-343, 1979). In examining how the cane toad avoids inhibiting its own sodium pumps, work on the heart showed that 1) cane toads possess a similar number of cardiac sodium pumps as other vertebrates, and 2) normal plasma K+ levels completely prevent ouabain, and presumably resibufogenin, from binding to cardiac sodium pumps of the cane toad. Other species, i.e., rat (Rattus norvegicus) and salamander (Ambystoma mexicanum), did not show K+ protection of their cardiac ouabain binding sites up to normal plasma K+ levels. These species do not possess the high level of endogenous ouabain-like substance found in the toad. K+ demonstrated a capacity to protect the enzymatic activity of the toad heart sodium pumps from the inhibitory effects of ouabain.

Else PL

1994-09-01

97

Resting respiratory behavior in minimally instrumented toads - effects of very long apneas on blood gases and pH  

Directory of Open Access Journals (Sweden)

Full Text Available Resting respiratory behavior of Bufo marinus in minimally instrumented toads is described for a period of 24 hours in which the animals are left undisturbed. Torpor-related long apneas are described and their implications for blood gas levels are investigated. Results show that the resting ventilation rate of Bufo marinus is much lower than that reported so far. Levels of arterial oxygen, carbon dioxide, and pH are monitored during artificial long apneas induced by anesthesia. The toads showed an unexpected ability to unload carbon dioxide by non-respiratory means, even while being kept on dry plastic box with no access to water. Oxygen arterial partial pressure dropped to very low levels after one hour of apnea. This suggests that these animals may endure very well severe hypoxia for long periods of time while in torpor.

Coelho F. C.; Smatresk N. J.

2003-01-01

98

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

Directory of Open Access Journals (Sweden)

Full Text Available Karyological and flow cytometric (FCM) analyses were performed on a group of 14 green toads of the Bufo viridis species from seven Eurasian populations. Both approaches gave concordant results concerning the DNA ploidy level. All the populations examined were represented exclusively by diploid or tetraploid specimens, except one, where triploids were found. Results evidenced an interpopulation variability in DNA content against the same ploidy level, as well as an unusually high number of triploids in a particular reproductive place. The origin of polyploidy and the presence and persistence of a high number of triploids in a particular population are discussed.

D Cavallo; R De Vita; P Eleuteri; L Borkin; V Ermechenko; G Odierna; E Balletto

2010-01-01

99

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 during the reproductive period, no significant differences were encountered. In addition, red blood cell count and hematocrit values were found to be higher among all sexes in the reproductive period than in the pre-reproductive period.

Fatma DÖNMEZ; Murat TOSUNO?LU; Çi?dem GÜL

2009-01-01

100

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

Directory of Open Access Journals (Sweden)

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

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

2008-01-01

 
 
 
 
101

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O sapo do gênero Bufo possui nas suas glândulas paratóides uma secreção mucóide contendo toxinas como bufaginas e Bufotoxinas, que são esteróides cardiogênicos. Os cães podem atacar os sapos, entrando em contato com o veneno por meio das mucosas. Um canino, da raça Bulldog Francês, foi encaminhado 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 (more) . Na necropsia o canino apresentava pulmões aumentados de volume, avermelhados e com edema, e rins de coloração vermelho-escura. As alterações microscópicas indicaram congestão, hemorragia e edema pulmonar. Nos rins, no baço e nos linfonodos foi observada congestão. As análises toxicológicas para os venenos de rotina foram negativas. Porém, a investigação do veneno de sapo a partir de cromatografia por camada delgada e gasosa demonstrou resultado positivo, revelando ser esta a causa da morte do canino. Abstract in english The toads of the genus Bufo produce, in their parotoid glands, a mucoid secretion containing toxins such as bufagins and Bufotoxins, which are cardiogenic steroids. The mucous membranes of dogs can absorb this venom when they attack the toads. A French bulldog with a history of probable toad venom intoxication was referred to Veterinary Pathology Section of Federal University of Rio Grande do Sul (UFRGS) for necropsy. The necropsy revealed enlarged, reddish, edematous lun (more) gs, 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.

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

2008-09-01

102

Toad Pocket Reference for Oracle  

CERN Document Server

Toad is an enormously popular interactive environment tool for Oracle development and administration. It allows developers to build, test, debug, and format their code via an easy-to-use graphical user interface, available in both freeware and commercial versions. Toad makes developers far more productive; using Toad, you'll find that program changes that once took hours can now be completed in minutes. Toad allows developers to browse their database tables, procedures, and object types; use code templates; and show errors. It also simplifies database administration by providing a way for D

Smith, Jeff; Scalzo, Bert

2005-01-01

103

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

Directory of Open Access Journals (Sweden)

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

Tonglei Yu; Yanshu Guo

2012-01-01

104

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

UK PubMed Central (United Kingdom)

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

Ujvari B; Mun HC; Conigrave AD; Bray A; Osterkamp J; Halling P; Madsen T

2013-01-01

105

C23 Steroids from the Venom of Bufo bufo gargarizans.  

Science.gov (United States)

Five new C23 steroids (1-5) together with five known bufadienolides (6-10) were isolated from the venom of Bufo bufo gargarizans (ChanSu in Chinese). The structures of the new steroids were elucidated by extensive spectroscopic methods in combination with X-ray diffraction analysis. Among these C23 steroids, only compound 3 showed cytotoxicities against HepG2 and A549 cancer cells, with respective IC50 values of 26.8 ± 8.3 and 45.6 ± 2.5 ?M. In contrast, the bufadienolides (7-10) displayed potent inhibitory activities against these cancer cells, with respective IC50 values in the ranges 0.5-5.5 and 0.6-6.5 ?M, but relatively less cytotoxicity on normal mouse spleen cells. In addition, the Na(+)/K(+)-ATPase inhibitory activities of 2, 5, and 7 revealed that the lactone moiety of a bufadienolide was important for the inhibitory activity. PMID:24050254

Tian, Hai-Yan; Luo, Shi-Lin; Liu, Jun-Shan; Wang, Lei; Wang, Ying; Zhang, Dong-Mei; Zhang, Xiao-Qi; Jiang, Ren-Wang; Ye, Wen-Cai

2013-09-19

106

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 prop...

Ratnikov, V. Yu

107

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 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 anuros: 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, hemat? (more) ?crito 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 level (more) s, 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

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

2000-05-01

108

Water uptake by Bufo melanostictus, as affected by osmotic gradients, vasopressin and temperature.  

UK PubMed Central (United Kingdom)

1. The rate of water uptake across the skin was studied in the live toad, Bufo melanostictus. When toads were kept in distilled water at 29 degrees C the uptake of water amounted to 16.9 +/- 1.3 mul./cm(2)/hr; when bathed in sucrose or urea solutions, the water uptake diminished with increasing osmotic pressure. There was no water uptake observed when toads were kept in 200 m-osmolar sucrose or urea.2. Intramuscular injections of vasopressin increased the rate of water uptake from distilled water. There was a good relation between doses and responses over various time intervals. A dose of 4 m-u. vasopressin/g body wt. doubled the rate of water uptake over a period of 1 hr. The same dose of vasopressin doubled the rate of water uptake when the toads were kept in solutions of sucrose or urea of different osmolarity.3. The rate of water uptake when the toads were bathed in sodium chloride solutions was consistently 8 mul./cm(2)/hr greater than when bathed in sucrose or urea solutions of equal osmolarity. There was no water uptake when the sodium chloride solution was 285 m-osmolar.4. Vasopressin (4 m-u./g) injected intramuscularly doubled the rate of water uptake from sodium chloride solutions of different osmolarity.5. With solutions of potassium chloride, sodium nitrate, and potassium nitrate, in concentrations up to 150 m-osmoles/l., the rate of water uptake was found to be the same as with solutions of sodium chloride of the same osmolarity. Similarly, it was doubled by injection of vasopressin (4m-u./g).6. The effect of temperature on the rate of water uptake before and after injection of vasopressin was investigated in toads kept in distilled water, sucrose, or sodium chloride solutions. For temperatures between 20 and 37 degrees C, vasopressin (4 m-u./g) reduced the activation energy involved in the process of water uptake by 4000 cal.7. The results agree with the view that water uptake follows a diffusion process which is facilitated by vasopressin, possibly as a result of increasing the size or number of available pores.

Dicker SE; Elliott AB

1967-05-01

109

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

International Nuclear Information System (INIS)

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

1990-01-01

110

Haematological changes in Bufo maculatus treated with sublethal concentrations of Cadmium  

Directory of Open Access Journals (Sweden)

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

Lawrence Ikechukwu Ezemonye; Alex Ajeh Enuneku

2011-01-01

111

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.

2010-01-01

112

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

UK PubMed Central (United Kingdom)

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

Hartigan A; Fiala I; Dyková I; Jirk? M; Okimoto B; Rose K; Phalen DN; Šlapeta J

2011-01-01

113

A coalescent framework for comparing alternative models of population structure with genetic data: evolution of Celebes toads.  

UK PubMed Central (United Kingdom)

Isolation of populations eventually leads to divergence by genetic drift, but if connectivity varies over time, its impact on diversification may be difficult to discern. Even when the habitat patches of multiple species overlap, differences in their demographic parameters, molecular evolution and stochastic events contribute to differences in the magnitude and distribution of their genetic variation. The Indonesian island of Sulawesi, for example, harbours a suite of endemic species whose intraspecific differentiation or interspecific divergence may have been catalysed by habitat fragmentation. To further test this hypothesis, we have performed phylogenetic and coalescent-based analyses on molecular variation in mitochondrial and nuclear DNA of the Celebes toad (Bufo celebensis). Results support a role for habitat fragmentation that led to a population structure in these toads that closely matches distributions of Sulawesi macaque monkeys. Habitat fragmentation, therefore, may also have affected other groups on this island.

Evans BJ; McGuire JA; Brown RM; Andayani N; Supriatna J

2008-08-01

114

A coalescent framework for comparing alternative models of population structure with genetic data: evolution of Celebes toads.  

Science.gov (United States)

Isolation of populations eventually leads to divergence by genetic drift, but if connectivity varies over time, its impact on diversification may be difficult to discern. Even when the habitat patches of multiple species overlap, differences in their demographic parameters, molecular evolution and stochastic events contribute to differences in the magnitude and distribution of their genetic variation. The Indonesian island of Sulawesi, for example, harbours a suite of endemic species whose intraspecific differentiation or interspecific divergence may have been catalysed by habitat fragmentation. To further test this hypothesis, we have performed phylogenetic and coalescent-based analyses on molecular variation in mitochondrial and nuclear DNA of the Celebes toad (Bufo celebensis). Results support a role for habitat fragmentation that led to a population structure in these toads that closely matches distributions of Sulawesi macaque monkeys. Habitat fragmentation, therefore, may also have affected other groups on this island. PMID:18511406

Evans, Ben J; McGuire, Jimmy A; Brown, Rafe M; Andayani, Noviar; Supriatna, Jatna

2008-08-23

115

Hydrosmotic effect of angiotensin II in the toad skin: role of cyclic AMP.  

UK PubMed Central (United Kingdom)

The mechanism of action of the hydrosmotic response of the isolated skin of the toad Bufo arenarum Hensel to angiotensin II was studied by means of an indirect pharmacological approach. Angiotensin II (2.10(-10) M), vasopressin (2.10(-13) M) and theophylline (10(-4) and 10(-3) M) in subliminal doses produced a significant increase on water permeability when added in different paired combinations. Angiotensin II (2.10(-7) M) and vasopressin (2.10(-8) M) in doses producing significant effects on water permeability increased the response to submaximal doses of epinephrine (10(-6) M) but not to higher doses (10(-5) M). Acid pH (6.4) and prostaglandin E1 (2.10(-7) M) reduced significantly the hydrosmotic response to angiotensin II, but in contrast with the toad bladder, the effect was not completely abolished. Present results support the view that the hydrosmotic effect of angiotensin II in toad skin is mediated by the adenylate cyclase - cyclic AMP system.

Coviello A; Brauckmann ES; de Atenor MS; Apud JA; Causarano J

1975-01-01

116

Hydrosmotic effect of angiotensin II in the toad skin: role of cyclic AMP.  

Science.gov (United States)

The mechanism of action of the hydrosmotic response of the isolated skin of the toad Bufo arenarum Hensel to angiotensin II was studied by means of an indirect pharmacological approach. Angiotensin II (2.10(-10) M), vasopressin (2.10(-13) M) and theophylline (10(-4) and 10(-3) M) in subliminal doses produced a significant increase on water permeability when added in different paired combinations. Angiotensin II (2.10(-7) M) and vasopressin (2.10(-8) M) in doses producing significant effects on water permeability increased the response to submaximal doses of epinephrine (10(-6) M) but not to higher doses (10(-5) M). Acid pH (6.4) and prostaglandin E1 (2.10(-7) M) reduced significantly the hydrosmotic response to angiotensin II, but in contrast with the toad bladder, the effect was not completely abolished. Present results support the view that the hydrosmotic effect of angiotensin II in toad skin is mediated by the adenylate cyclase - cyclic AMP system. PMID:189568

Coviello, A; Brauckmann, E S; de Atenor, M S; Apud, J A; Causarano, J

1975-01-01

117

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

118

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

Directory of Open Access Journals (Sweden)

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

Biju SD; Van Bocxlaer Ines; Giri Varad B; Loader Simon P; Bossuyt Franky

2009-01-01

119

Body size variation of four latitudinally-separated populations of a toad species: age and growth rate as the proximate determinants.  

UK PubMed Central (United Kingdom)

Age and growth rate are critical parameters determining the body size of adult anurans, which grow indeterminately. Therefore, evaluating their relative importance and selective pressures acting on them may help to explain variation in body size of anurans across geographical populations. Based on the data on body size and skeletochronological age of 4 Asiatic toad (Bufo gargarizans) populations that are widely separated in latitude, the present study showed that toads at the northern extremity of the range were the oldest, on average, and grew relatively fast, toads at the southern end of the range were relatively old but grew fastest, whereas mid-latitude toads were intermediate in both traits. These results indicated that relative contributions of age and growth rate to body size differed among populations. From a life history perspective, greater age attained by toads at higher latitudes should result from delayed maturation, and faster growth from an adaptive response to strong seasonal time constraints; in contrast, selective pressures on the 2 parameters at lower latitudes might be associated, respectively, with low adult death rates and longer favorable growing seasons.

Yu T; Lu X

2013-09-01

120

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 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 denominada Karyolysus aquai (Phisalix) por realizar o ciclo agâmico nas células endoteliais. Descreve-se a Haemogregarina legeri nov. sp. Estuda-se um Toxoplasma no sangue (more) 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 esquizogonico de la Haemogregarina aquai Phisalix 1930, proponiendo denominaria Karyolysus aquai (Phisalix) por realizar su ciclo agámico en las células endoteliales. Se describ (more) e 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 Haemogre (more) garina 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

1956-10-01

 
 
 
 
121

[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

122

[Helminth fauna of Bufo raddei in Transbaikalia  

UK PubMed Central (United Kingdom)

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.

Shchepina NA; Baldanova DR

2010-03-01

123

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

Directory of Open Access Journals (Sweden)

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

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

2008-01-01

124

Hopping isn't always about the legs: forelimb muscle activity patterns during toad locomotion.  

UK PubMed Central (United Kingdom)

Although toads are not known for their jumping ability, they are excellent at landing, using their forelimbs to stabilize and decelerate the body as they transition between hops. Forelimb muscles must play important roles during this landing behavior, but to date our understanding of forelimb muscle function during jumping in anurans, particularly after takeoff, is quite limited. Here, we use simultaneous high-speed video and electromyography to characterize the timing and intensity of electrical activity patterns of six muscles that act at the shoulder or elbow joints in the cane toad, Bufo marinus. In particular, we aim to address the importance of these muscles with respect to various potential roles during hopping (e.g. contributing to propulsion during takeoff, resisting impact forces during landing). Five of the six recorded muscles exhibited their highest average intensities during the aerial phase of the hop, with the most intense activity present near forelimb touchdown. In contrast, no muscles exhibited high levels of activity in the initial phase of takeoff. We interpret these data to indicate that the forelimb muscles studied here are likely unimportant in augmenting force production during takeoff, but are critical for both mid-air forelimb positioning and resisting the forces associated with impact. The onset timing of elbow extensors seems to occur at a nearly fixed interval before impact, regardless of hop length, suggesting that these muscles are particularly tuned to resisting impact.

Akella T; Gillis GB

2011-01-01

125

Differences and similarities among parotoid macrogland secretions in South American toads: a preliminary biochemical delineation.  

UK PubMed Central (United Kingdom)

Amphibians are known by cutaneous glands, spread over the skin, containing toxins (proteins, peptides, biogenic amines, steroidal bufadienolides, and alkaloids) used as chemical defense against predators and microbial infection. Toads are characterized by the presence of parotoid macroglands. The common toads have lately been divided into two genera: Bufo (Europe, Asia, and Africa) and Rhinella (South America). Basal Rhaebo genus is exclusively of Central America and Amazon region. Although Rhinella and Rhaebo are related, species may share differences due to the diversity of environments that they live in. In this work, we have performed a biochemical characterization of the components of the poison of eight Rhinella species and one Rhaebo by means of RP-HPLC with either UV or MS detection and by SDS-PAGE, in order to verify whether phylogenetic and biological differences, such as habitat, diet, and defensive strategies, between them may also be reflected in poison composition. Although some components were common among the secretions, we were able to identify exclusive molecules to some species. The fact that closely related animals living in different habitats secrete different molecules into the skin is an indication that biological features, and not only evolution, seem to directly influence the skin secretion composition.

Sciani JM; Angeli CB; Antoniazzi MM; Jared C; Pimenta DC

2013-01-01

126

Identification and detection of the isolated sinus venosus from the Asian toad.  

Science.gov (United States)

The pacemaker activity of mammalian sinoatrial node (SAN) of the heart plays a fundamental role in the integration of vital functions. Studying factors such as drugs that influence pacemaker activity of SAN has its significance. In this study, we isolated sinus venosus, SAN from toads (Bufo gargarizans), and analysed its electronic signal, histological characteristics and the influence of acetylcholine (ACh) and ivabradine on its pacemaker activity using PowerLab® and Chart® 5.0 software. We found that when isolated sinus venosus was treated with ACh, its histological distribution was disorganized and inter-beat (RR) interval was also broadened. The high frequency normalized unit (HFnu) and Poincaré plot of heart rate variability (HRV) of the isolated sinus venosus was also altered upon ACh treatment in a time-dependent and dose-dependent manner. When treated with ivabradine, these parameters of HRV such as square root of the mean of the squared differences between adjacent NN intervals (RMSSD) and HFnu were in the upward tendency, but low frequency normalized unit and low frequency/high frequency were in the opposite tendency. Taken together, we have developed a new model for studying the influences of drugs on autorhythmicity using isolated sinus venosus of the toad. With this model, we showed that ACh and ivabradine may affect the pacemaker activity by stimulating muscarinic receptor or inhibiting I(f) current, respectively. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23348247

Deng, Xin; Guan, Chao; Wang, Yang; Zhang, Bing; Li, Sen; Sun, Guiyuan; Hao, Liying; Li, Gensong

2013-01-25

127

Identification and detection of the isolated sinus venosus from the Asian toad.  

UK PubMed Central (United Kingdom)

The pacemaker activity of mammalian sinoatrial node (SAN) of the heart plays a fundamental role in the integration of vital functions. Studying factors such as drugs that influence pacemaker activity of SAN has its significance. In this study, we isolated sinus venosus, SAN from toads (Bufo gargarizans), and analysed its electronic signal, histological characteristics and the influence of acetylcholine (ACh) and ivabradine on its pacemaker activity using PowerLab® and Chart® 5.0 software. We found that when isolated sinus venosus was treated with ACh, its histological distribution was disorganized and inter-beat (RR) interval was also broadened. The high frequency normalized unit (HFnu) and Poincaré plot of heart rate variability (HRV) of the isolated sinus venosus was also altered upon ACh treatment in a time-dependent and dose-dependent manner. When treated with ivabradine, these parameters of HRV such as square root of the mean of the squared differences between adjacent NN intervals (RMSSD) and HFnu were in the upward tendency, but low frequency normalized unit and low frequency/high frequency were in the opposite tendency. Taken together, we have developed a new model for studying the influences of drugs on autorhythmicity using isolated sinus venosus of the toad. With this model, we showed that ACh and ivabradine may affect the pacemaker activity by stimulating muscarinic receptor or inhibiting I(f) current, respectively. Copyright © 2013 John Wiley & Sons, Ltd.

Deng X; Guan C; Wang Y; Zhang B; Li S; Sun G; Hao L; Li G

2013-01-01

128

[Cloning and bioinformatic analysis of TAGLN2 cDNA of Bufo japonicus formosus].  

Science.gov (United States)

To study the bioactive polypeptides included in Bufo skin and its secretions the plasmid skin cDNA library of adult Japanese toad Bufo japonicus formosus was prepared. The pSD64TR has been used as the vector and the cloning sites are Xho I and EcoR I. To screen cDNAs encoding bioactive components, the plasmid cDNA library was transformed into E. coli DH5 competent cells, and positive colonies were screened by colony PCR (polymerase chain reaction). The suspension of a single colony in LB medium was used as the template, SP6 (the upstream primer of the plasmid cDNA library) and a primer with Xho I site and polyT were used as the primers. As the result, 465 positive colonies out of 1 344 were obtained and their plasmid were collected and sequenced. By homologous analysis, it was found that one of the cDNAs encoding a peptide with high homolog with transgelin-2, which was registered in GenBank (accession number: JX197456), and it was indicated as a partial cDNA sequence with a deletion at the 5' end. The transcript is 997 bp consisting of 31 bp 5', 618 bp 3' untranslated region (UTR) and an open reading frame (ORF) of 348 bp encoding a polypeptide of 115 amino acids. In the putative protein product, there is a calponin homology domain, two cysteine residues for a disulfide bond and three a-helix domains, and five potential phosphorylation sites. The homologous analysis indicates 90% similarity with Xenopus (Silurana) tropicalis and 89% with Xenopus laevis, and 71%-85% with other species. PMID:23672022

Zhuge, Hui; Yuan, Jin-Qiang; Zhang, Shu-Fang; Yang, Xian-Yu

2013-02-01

129

[Cloning and bioinformatic analysis of TAGLN2 cDNA of Bufo japonicus formosus].  

UK PubMed Central (United Kingdom)

To study the bioactive polypeptides included in Bufo skin and its secretions the plasmid skin cDNA library of adult Japanese toad Bufo japonicus formosus was prepared. The pSD64TR has been used as the vector and the cloning sites are Xho I and EcoR I. To screen cDNAs encoding bioactive components, the plasmid cDNA library was transformed into E. coli DH5 competent cells, and positive colonies were screened by colony PCR (polymerase chain reaction). The suspension of a single colony in LB medium was used as the template, SP6 (the upstream primer of the plasmid cDNA library) and a primer with Xho I site and polyT were used as the primers. As the result, 465 positive colonies out of 1 344 were obtained and their plasmid were collected and sequenced. By homologous analysis, it was found that one of the cDNAs encoding a peptide with high homolog with transgelin-2, which was registered in GenBank (accession number: JX197456), and it was indicated as a partial cDNA sequence with a deletion at the 5' end. The transcript is 997 bp consisting of 31 bp 5', 618 bp 3' untranslated region (UTR) and an open reading frame (ORF) of 348 bp encoding a polypeptide of 115 amino acids. In the putative protein product, there is a calponin homology domain, two cysteine residues for a disulfide bond and three a-helix domains, and five potential phosphorylation sites. The homologous analysis indicates 90% similarity with Xenopus (Silurana) tropicalis and 89% with Xenopus laevis, and 71%-85% with other species.

Zhuge H; Yuan JQ; Zhang SF; Yang XY

2013-02-01

130

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

Scientific Electronic Library Online (English)

Full Text Available 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 o (more) f amphibians and may act as a neurotransmitter or neuromodulator. We tested the hypothesis that NO plays a role in CO2-drive to breathing, specifically in the NI comparing pulmonary ventilation, breathing frequency and tidal volume, after microinjecting 100 nmol/0.5 µl of L-NAME (a nonselective NO synthase inhibitor) into the NI of toads (Bufo paracnemis) exposed to normocapnia and hypercapnia. Control animals received microinjections of vehicle of the same volume. Under normocapnia no significant changes were observed between control and L-NAME-treated toads. Hypercapnia caused a significant (P<0.01) increase in ventilation only after intracerebral microinjection of L-NAME. Exposure to hypercapnia caused a significant increase in breathing frequency both in control and L-NAME-treated toads (P<0.01 for the control group and P<0.001 for the L-NAME group). The tidal volume of the L-NAME group tended to be higher than in the control group under hypercapnia, but the increase was not statistically significant. The data indicate that NO in the NI has an inhibitory effect only when the respiratory drive is high (hypercapnia), probably acting on tidal volume. The observations reported in the present investigation, together with other studies on the presence of NOS in amphibians, indicate a considerable degree of phylogenetic conservation of the NO pathway amongst vertebrates.

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

1999-11-01

131

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

UK PubMed Central (United Kingdom)

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

Pallister JA; Halliday DC; Robinson AJ; Venables D; Voysey RD; Boyle DG; Shanmuganathan T; Hardy CM; Siddon NA; Hyatt AD

2011-01-01

132

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-05-15

133

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

International Nuclear Information System (INIS)

[en] 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

2007-01-01

134

Effects of fluoride on metamorphosis, thyroid and skeletal development in Bufo gargarizans tadpoles.  

UK PubMed Central (United Kingdom)

This study examined the effects of chronic fluoride exposure on metamorphosis, thyroid and skeletal development in tadpoles of Chinese Toad, Bufo gargarizans. The tadpoles were exposed to fluoride concentrations either at 0, 1, 5, 10, or at 50 mg L(-1) from Gosner stage 26 to Gosner stage 42. Body weight, total length and percentage of tadpoles reaching metamorphosis climax were recorded, and thyroid histological examinations were employed. In addition, mRNA expression of both deiodinase type 2 (D2) and deiodinase type 3 (D3) was analyzed by using RT-PCR and skeletal systems were investigated by using double-staining methodology at stage 42. Results showed that total length and body weight were unaffected by fluoride exposure at all concentrations while metamorphosis was strongly inhibited only by 50 mg L(-1) fluoride. Histomorphological measurements showed the percentage of colloid depletion in thyroid gland increased significantly, while the average diameter of follicles was significantly shorter at 50 mg L(-1) concentration. In addition, fluoride at 5 mg L(-1) can stimulate bone mineralization, while fluoride at 50 mg L(-1) can retard deposition of calcium. In conclusion, our study suggests that 50 mg L(-1) fluoride could damage follicular cells in thyroid gland and induce a sharp reduction in thyroid hormone probably through the up-regulation of D3 mRNA expression, and these influences on thyroid system may delay metamorphosis as well as ossification in bone tissue by inhibiting calcium deposition.

Zhao H; Chai L; Wang H

2013-09-01

135

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

UK PubMed Central (United Kingdom)

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.

Lance SL; Flynn RW; Erickson MR; Scott DE

2013-06-01

136

Analyses of the karyotype of the henan bufo raddei strauch  

UK PubMed Central (United Kingdom)

The chromosome specimens form the bone marrow cell of Bufo Raddei strauch were prepared by steam-fixed method and the karyotype was analysed in conventional methods.Karyotypes of 2n=22,20m+2 sm were characterised by six male.They are metacentric chromosomes except No.4 which is submetacentric.Compared with Beijing Bufo Raddei strauch which have satellite in the terminal of the long arm of No.4,the Henan Bufo Raddei strauch have satellite in the terminal of the short arm of the same chromosome pair.THe several methods that would increase mitotic index were compared.

Zhou Jie; Dong Zimei; Du Qiyan; Liu Haiying

2004-01-01

137

An interesting case of cardiotoxicity due to bufotoxin (toad toxin).  

UK PubMed Central (United Kingdom)

Consumption of toads for their aphrodisiac effect is a common practice in Laos, China and in some parts of India. Toad secretions from parotid and skin contains toxin similar to cardiac glycosides. It results in bradycardia and cardiac dysfunction leading on to death in some cases. We report a case of toad poisoning in a young previously healthy male.

Ashok G; Ramkumar; Sakunthala SR; Rajasekaran D

2011-11-01

138

An interesting case of cardiotoxicity due to bufotoxin (toad toxin).  

Science.gov (United States)

Consumption of toads for their aphrodisiac effect is a common practice in Laos, China and in some parts of India. Toad secretions from parotid and skin contains toxin similar to cardiac glycosides. It results in bradycardia and cardiac dysfunction leading on to death in some cases. We report a case of toad poisoning in a young previously healthy male. PMID:22616345

Ashok, G; Ramkumar; Sakunthala, S R; Rajasekaran, D

2011-11-01

139

Effect of ethanol on the water permeability and short-circuit current of the urinary bladder of the toad and the response to vasopressin, adenosine-3',5'-monophosphate and theophylline.  

UK PubMed Central (United Kingdom)

The effects of ethanol on the water permeability and short-circuit current of the isolated urinary bladder of the toad, Bufo marinus, were investigated. Ethanol alone did not alter the flow of water along an osmotic gradient. The increase in osmotic water flow caused by vasopressin, theophylline or cyclic adenosine-3',5'-monophosphate was inhibited by 4 to 40 mg per ml of ethanol in the mucosal or serosal bathing medium. The inhibition was more marked when ethanol was added to the serosal bathing medium, in spite of the increase in the osmotic gradient across the toad bladder caused by the ethanol. Ethanol had no effect on the increase in sodium transport (short-circuit current) due to vasopressin, although there was a significant inhibition of base-line short-circuit current. It is possible that the water diuresis due to ethanol may result in part from an inhibition of the effect of vasopressin on the collecting duct.

Meier KE; Mendoza SA

1976-01-01

140

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

UK PubMed Central (United Kingdom)

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

González-Bernal E; Greenlees M; Brown GP; Shine R

2012-01-01

 
 
 
 
141

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

Science.gov (United States)

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

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

2012-11-07

142

Sperm concentration and fertilization rate in Bufo arenarum (Amphibia: Anura).  

UK PubMed Central (United Kingdom)

The influence of sperm concentration upon the fertilization rate of Bufo arenarum oocytes was determinated. The experimental results were analysed according to the theories of Rothschild and Swann, and Hultin and Hagström for Psammechinus miliaris. The experimental results agreed with the predictions of the latter theory. Since Bufo arenarum and Psammechinus miliaris oocytes differ in both size and disposition of jelly envelopes, the postulations of Hultin and Hagström's theory appear to have a general validity.

Cabada MO

1975-04-01

143

Technique for producing instant toad oil  

UK PubMed Central (United Kingdom)

The invention relates to a technique for producing instant toad oil, comprising the following steps: taking a dry product of toad oil, sterilizing by microwave, mixing the sterilized toad oil and drinking water according to the ratio of parts by weight of 1:45, controlling the temperature of the drinking water at 40 DEG C and soaking for 4.5 hours for standby mixing honey and the drinking water according to the ratio of parts by weight of 1:2, heating, stirring to dissolve the mixture and obtaining hydromel for standby removing impurities and water from the soaked toad oil, adding 0.3 part of hydromel according to parts by weight, then adding 3 parts of drinking water, 0.8 part of monosodium glutamate and 1.5 parts of table salt and stirring and putting into a flat-bottom stainless steel kettle filled with boiling water, preheating for 15 minutes, then heating for 40 minutes, cooling and packaging the drinking water is boiled off for 5 minutes and the toad oil produced by the invention is edible at any moment, is clean and sanitary, is easy to absorb and has high bioavailability, good mouth feel, delicious taste and comfortable eating.

XIAOXIAN SUN

144

Effects of the landscape on boreal toad gene flow: does the pattern-process relationship hold true across distinct landscapes at the northern range margin?  

UK PubMed Central (United Kingdom)

Understanding the impact of natural and anthropogenic landscape features on population connectivity is a major goal in evolutionary ecology and conservation. Discovery of dispersal barriers is important for predicting population responses to landscape and environmental changes, particularly for populations at geographic range margins. We used a landscape genetics approach to quantify the effects of landscape features on gene flow and connectivity of boreal toad (Bufo boreas) populations from two distinct landscapes in south-east Alaska (Admiralty Island, ANM, and the Chilkat River Valley, CRV). We used two common methodologies for calculating resistance distances in landscape genetics studies (resistance based on least-cost paths and circuit theory). We found a strong effect of saltwater on genetic distance of CRV populations, but no landscape effects were found for the ANM populations. Our discordant results show the importance of examining multiple landscapes that differ in the variability of their features, to maximize detectability of underlying processes and allow results to be broadly applicable across regions. Saltwater serves as a physiological barrier to boreal toad gene flow and affects populations on a small geographic scale, yet there appear to be few other barriers to toad dispersal in this intact northern region.

Moore JA; Tallmon DA; Nielsen J; Pyare S

2011-12-01

145

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

Science.gov (United States)

...Plants; Revised Critical Habitat for the Arroyo Toad AGENCY: Fish and Wildlife Service...designation of critical habitat for the arroyo toad (Anaxyrus californicus) under the...designation of critical habitat for the arroyo toad; revisions to proposed...

2010-06-29

146

Toad poisoning in three dogs: case reports  

Directory of Open Access Journals (Sweden)

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

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

2009-01-01

147

Toad poisoning in three dogs: case reports  

Scientific Electronic Library Online (English)

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

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

2009-01-01

148

The effect of metal ions and antidiuretic hormone on oxygen consumption in toad bladder.  

UK PubMed Central (United Kingdom)

1. The sodium-dependent oxygen consumption of pieces of toad bladder (Bufo marinus) has been investigated using an oxygen electrode.2. The effect of polyvalent cations (Ca(2+), Sr(2+), Mg(2+), Eu(3+), La(3+) and Mn(2+)) on sodium-dependent oxygen consumption has been measured. All cations inhibited oxygen consumption, the order of effectiveness being Ca(2+) > Sr(2+) > Mg(2+) > Mn(2+) > Eu(3+) > La(3+).3. Treatment of bladder pieces with antidiuretic hormone (50 m-u./ml.) decreased the effectiveness of Ca(2+) and Sr(2+) as inhibitors of sodium-dependent oxygen consumption. Mn(2+), Eu(2+) and La(2+) were more effective after hormonal treatment, while the effectiveness of Mg(2+) was unaltered.4. The results have been interpreted in terms of a model in which sodium entry to the transporting mechanisms of the epithelium is controlled by Ca(2+), and in which antidiuretic hormone alters Ca(2+) binding and so affects sodium transport.

Cuthbert AW; Wong PY

1971-12-01

149

Comparison of the sequence and structure of transcription factor IIIA from Bufo americanus and Rana pipiens.  

Science.gov (United States)

Amino acid (aa) sequences of transcription factor IIIA (TFIIIA) from the toad, Bufo americanus, and the grass frog, Rana pipiens, were determined by cDNA cloning and DNA sequencing. The 3'-untranslated regions of the cDNAs reveal that the TFIIIA gene polyadenylation signal is ATTAAA, rather than the conventional AATAAA. The B. americanus and R. pipiens proteins share about 60% aa sequence homology with each other and with Xenopus laevis TFIIIA. Although these results indicate that TFIIIA has more sequence variation than other DNA-binding proteins, a number of conserved features are evident and of likely functional significance. These include potential guanine nucleotide-binding sites at arginines in zinc fingers (ZnF) II, V, and IX, acidic residues between metal-coordinating cysteines, and a basic region in the C-terminal tail possibly involved in transcription promotion. Sequence similarity also exists in an aa stretch bridging the ninth ZnF and C-terminal tail of both TFIIIA and the 5S RNA-binding protein, p43. DNase I protection analyses demonstrate that B. americanus and R. pipiens TFIIIA interact with the internal control region (ICR) of the Xenopus borealis 5S RNA-encoding gene (5S) in different manners: the B. americanus interaction is similar to X. laevis TFIIIA, protecting the entire 5S gene ICR (nt +96 to +43) from DNase I digestion, whereas the R. pipiens TFIIIA strongly protects the ICR from nt +96 up to +78 and less strongly from +78 to +43. Possibly accounting for the binding differences observed, R. pipiens and R. catesbeiana oocyte 5S RNAs (and by inference 5S genes) were found to contain a G or U at nt position 50 while B. americanus, X. laevis, and other eukaryotic 5S RNAs have an A in the analogous position (nt 53 in generalized eukaryotic structure). PMID:1398134

Gaskins, C J; Smith, J F; Ogilvie, M K; Hanas, J S

1992-10-21

150

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

Scientific Electronic Library Online (English)

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

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

2010-02-01

151

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

Directory of Open Access Journals (Sweden)

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

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

2010-01-01

152

Preparation method of detoxification tablet with toad and poria  

UK PubMed Central (United Kingdom)

The invention relates to a method for producing toad Siberian cocklebur toxicide, wherein the excretion of toad adenohypophysis and several components of toad have significant toxicide function and cancer release function. The invention uses biological enzymolysis ferment technique to prepare the effective components of toad. The Poria cocos mushroom has more than 75% beta-pachyman with inactivity on cancer resistance, but the pachymaran that cuts off branch chain has activity on cancer resistance the polyporus umbellatus contains soluble polyporus umbellatus 1(Gu-1) with significant cancer resistance and immunity treatment. The invention can resist radiation and chemical damage.

CHEN QIZHONG LI

153

Resting respiratory behavior in minimally instrumented toads - effects of very long apneas on blood gases and pH Comportamento respiratório em repouso de sapos minimamente implantados - efeitos de apnéias de longa duração sobre o pH e gases sanguíneos  

Directory of Open Access Journals (Sweden)

Full Text Available Resting respiratory behavior of Bufo marinus in minimally instrumented toads is described for a period of 24 hours in which the animals are left undisturbed. Torpor-related long apneas are described and their implications for blood gas levels are investigated. Results show that the resting ventilation rate of Bufo marinus is much lower than that reported so far. Levels of arterial oxygen, carbon dioxide, and pH are monitored during artificial long apneas induced by anesthesia. The toads showed an unexpected ability to unload carbon dioxide by non-respiratory means, even while being kept on dry plastic box with no access to water. Oxygen arterial partial pressure dropped to very low levels after one hour of apnea. This suggests that these animals may endure very well severe hypoxia for long periods of time while in torpor.O comportamento respiratório em repouso de Bufo marinus é descrito em animais minimamente implantados por um período de 24 horas, durante as quais os animais permanecem em total isolamento. Um estado de torpor associado a longas apnéias é descrito, e suas implicações sobre os níveis de gases sanguíneos é investigada. Os resultados mostram que o ritmo ventilatório em repouso de Bufo marinus é muito mais baixo do que o relatado na literatura até o presente. Os níveis arteriais de oxigênio, dióxido de carbono e pH foram monitorados durante longas apnéias induzidas artificialmente por meio de anestesia. Os sapos demonstraram capacidade surpreendente de eliminar dióxido de carbono por meios não respiratórios mesmo estando confinados em uma caixa plástica seca sem acesso a água. A pressão parcial de oxigênio arterial caiu a níveis extremamente baixos após uma hora de apnéia. Esses resultados sugerem que esses animais podem suportar muito bem hipoxia severa por longos períodos durante o estado de torpor.

F. C. Coelho; N. J. Smatresk

2003-01-01

154

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 L

2012-01-01

155

Biogeographic patterns of Colombian frogs and toads  

International Nuclear Information System (INIS)

[en] 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

1997-01-01

156

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

UK PubMed Central (United Kingdom)

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.

Smith GR; Krishnamurthy SV; Burger AC; Mills LB

2011-02-01

157

Effects of copper, zinc and dragonfly kairomone on growth rate and induced morphology of Bufo arabicus tadpoles.  

Science.gov (United States)

It is well documented that many amphibian species can detect chemical signals from predatory invertebrates and subsequently develop alternate phenotypes that are protective against predation. The effects of metallic pollutants on the development of predator-induced morphology have not previously been reported. Tadpoles of the Arabian toad Bufo arabicus were exposed for 20 days to copper (0, 10 or 100 ?g/L), zinc (0, 10 or 100 ?g/L) and kairomones of larval dragonflies (Crocothemis erythrea 1 dragonfly/12 L) in a fully crossed design. The effects of these treatments of growth and body shape were measured. Measured copper concentrations after 24 h were 4.25 ?g/L±1.30 (10 ?g/L nominal) and 34.9 ?g/L±2.15 (100 ?g/L nominal). Measured zinc concentrations were 3.04 ?g/L±0.1 (10 ?g/L nominal) and 26.3 ?g/L±12.3 (100 ?g/L nominal). Tadpoles exposed to 34.9 ?g/L copper were significantly lighter and had a shorter body length than other groups. There was no direct effect of zinc on growth or tadpole shape. Tadpoles exposed to dragonfly kairomones were heavier, wider and had deeper bodies when viewed laterally and had longer tails but overall length was not affected. At 4.25 ?g/L copper differences between the control and predator-exposed phenotypes increased but at 34.9 ?g/L the phenotypes converged, indicating that copper may inhibit the induced response. PMID:21251714

Barry, Michael J

2011-01-19

158

Effects of copper, zinc and dragonfly kairomone on growth rate and induced morphology of Bufo arabicus tadpoles.  

UK PubMed Central (United Kingdom)

It is well documented that many amphibian species can detect chemical signals from predatory invertebrates and subsequently develop alternate phenotypes that are protective against predation. The effects of metallic pollutants on the development of predator-induced morphology have not previously been reported. Tadpoles of the Arabian toad Bufo arabicus were exposed for 20 days to copper (0, 10 or 100 ?g/L), zinc (0, 10 or 100 ?g/L) and kairomones of larval dragonflies (Crocothemis erythrea 1 dragonfly/12 L) in a fully crossed design. The effects of these treatments of growth and body shape were measured. Measured copper concentrations after 24 h were 4.25 ?g/L±1.30 (10 ?g/L nominal) and 34.9 ?g/L±2.15 (100 ?g/L nominal). Measured zinc concentrations were 3.04 ?g/L±0.1 (10 ?g/L nominal) and 26.3 ?g/L±12.3 (100 ?g/L nominal). Tadpoles exposed to 34.9 ?g/L copper were significantly lighter and had a shorter body length than other groups. There was no direct effect of zinc on growth or tadpole shape. Tadpoles exposed to dragonfly kairomones were heavier, wider and had deeper bodies when viewed laterally and had longer tails but overall length was not affected. At 4.25 ?g/L copper differences between the control and predator-exposed phenotypes increased but at 34.9 ?g/L the phenotypes converged, indicating that copper may inhibit the induced response.

Barry MJ

2011-05-01

159

The complete mitochondrial genome of the Bufo tibetanus (Anura: Bufonidae).  

UK PubMed Central (United Kingdom)

The total length of the Bufo tibetanus mitochondrial genome sequence is 17,405 bp. It consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 1 displacement loop (D-loop). Except for eight tRNAs and nd6 genes, all other mitochondrial genes are encoded on the heavy strand (H strand). Most of the 22 tRNA genes can fold into a typical cloverleaf secondary structure by tRNAscan-SE, except for tRNA(Ser). Molecular data presented here provide a useful toll for helping set the stage for further studies and the molecular evolution of the mitochondrial genome.

Wang X; Wang Y; Yue B; Zhang X; Liu S

2013-06-01

160

Clinical and electrocardiographic evaluation during experimental toad poisoning in dogs  

Scientific Electronic Library Online (English)

Full Text Available 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 evaluate the clinical and electrocardiographic aspects of dogs subjected to experimental toad poisoning, as well as their response to treatment with propranolol. Twenty dogs were (more) 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

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

2010-01-01

 
 
 
 
161

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  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese 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. Amba (more) s 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. Abstract in english 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 (more) 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.

Santana, AS.; Juncá, FA.

2007-02-01

162

A developmentally regulated lectin in Bufo arenarum embryos.  

UK PubMed Central (United Kingdom)

We report the levels of an endogenous beta-galactoside lectin activity from Bufo arenarum whole embryos extracts and specific inhibition by saccharides at different developmental stages. Specific activity measured against trypsinized rabbit red blood cells showed relatively high and fluctuating levels during early stages (up to about 76 h post-fertilization) which fell to significantly lower and more constant values at late stages (77-264 h post-fertilization). Lactose is the most potent inhibitor of this lectin activity, and saccharides having alpha-galactoside configurations are weaker inhibitors. At the last embryonic stage, the agglutinating activity showed a different sugar specificity which suggests either the modification of the preexistent lectin or the synthesis of another type of lectin. The possible physiological roles of these lectins in the blockage of polyspermy or in embryonic cell-cell interactions are discussed.

Elola MT; Fink-de-Cabutti NE; Herkovits H

1987-01-01

163

Stage dependent susceptibility to lead in Bufo arenarum embryos.  

UK PubMed Central (United Kingdom)

The stage dependent susceptibility to lead in amphibian development was studied by exposing Bufo arenarum embryos during neurulae, neuromuscular activity and gill circulation stages for twenty hours to 1 ppm Pb(2+). Survival, malformations and behavioral disorders were evaluated. The embryonic susceptibility to lead was markedly stage dependent. The survival at the neuromuscular activity stage was approximately half that of the other two periods; concerning malformations, the gill circulation stage was the least sensitive. The observed malformations consisted of failed closure of neural tube, hydropsy, small and cylindrical tails, reduced body size and incurvations in the body axis. Some alterations occurred in all experimental groups and therefore were considered non-dependent on the period of treatment. In all experimental embryos, neurological disorders such as trembles and loss of equilibrium were observed.

Pérez-Coll CS; Herkovits J

1990-01-01

164

Behavioral responses of bufo arenarum tadpoles to odonate naiad predation  

Directory of Open Access Journals (Sweden)

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.

MARÍA G. PEROTTI; LEE A. FITZGERALD; LILIANA MORENO; MARIANA PUETA

2006-01-01

165

Author! Author! Creator of Frog and Toad: Arnold Lobel  

Science.gov (United States)

This article presents a brief biography of author Arnold Lobel, perhaps best known for giving the world Frog and Toad. Arnold Lobel was born in Los Angeles, California, on May 22, 1933, and was raised by his grandparents in New York. He loved checking out books from the library when he was a little boy and sharing with his classmates the stories…

Brodie, Carolyn S.

2005-01-01

166

Clinical and electrocardiographic evaluation during experimental toad poisoning in dogs  

Directory of Open Access Journals (Sweden)

Full Text Available 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 evaluate 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 < 0.05). The animals in the poisoned group had gastrointestinal symptoms including emesis, intense salivation, hyperemic or congested oral mucosa and pasty diarrhea. Non-responsive mydriasis, nystagmus, depression, stupor, tachypnea, opisthotonus and ataxia were also manifested by 100% of the poisoned animals. Affected dogs had an increase in blood pressure, statistically significant throughout study. Five poisoned animals developed ventricular tachycardia and were treated with propranolol (0.5 mg/kg IV). All propranolol-treated animals returned to normal sinus rhythm, which evidences the efficacy of this drug to treat ventricular arrhythmias caused by toad venom.

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

2010-01-01

167

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

UK PubMed Central (United Kingdom)

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

Berlow EL; Knapp RA; Ostoja SM; Williams RJ; McKenny H; Matchett JR; Guo Q; Fellers GM; Kleeman P; Brooks ML; Joppa L

2013-01-01

168

Spatial and temporal distribution of amphibian road mortality with a Rana dalmatina and Bufo bufo predominance along the middle section of the Târnava Mare basin, Romania  

Directory of Open Access Journals (Sweden)

Full Text Available Here we present the results of the first extensive Transylvanian road mortality survey of Bufo bufo and Rana dalmatina. Fieldwork was carried out between February 15 and May 03, 2007 in the middle section of the Târnava Mare basin. In a total of seventeen surveys in 2007 altogether 83.3 km of roads were repeatedly investigated. 1437 R. dalmatina, 833 B. bufo and 30 other amphibian individuals were found on the road. Both predominant species are common for the area, and had a larger migration intensity during rainy nights. Most (over 85%) B. bufo individuals were recorded to cross roads in main migration corridors while this ratio was under 50% for R. dalmatina, which has important conservation consequence in the protection of these species from road traffic. The average width of main migration routes crossing roads was 188.8 m (Min-Max: 50-350m, SD = 101.11). These were localized for both predominant species using GPS, in order to allow further studies and assessment for conservation. As proved by the site visits in 2008, these localities remained stable over the two studied years.

Tibor HARTEL; Cosmin Ioan MOGA; Kinga ÖLLERER; Miklós PUKY

2009-01-01

169

Bufoténine et bufoténidine : des alcaloïdes aux vertus hallucinogènes et aphrodisiaques extraits du venin de crapaud Bufotenine and bufotenidine : hallucinogenic and aphrodisiac alleged alcaloids extracted from toad venom  

Directory of Open Access Journals (Sweden)

Full Text Available La bufoténine (5-hydroxy-N,N-diméthyltryptamine) est un alcaloïde indolique de la famille des tryptamines comme la sérotonine, la N-méthylsérotonine, la 5-méthoxy-N-méthyltryptamine et la mélatonine retrouvées dans les graines de certaines légumineuses ainsi que dans les sécrétions de la peau de différents amphibiens. Chez l'homme, ces molécules possèdent de puissantes propriétés psychotropes et sont impliquées dans les désordres mentaux temporaires ou dans des maladies du cerveau comme la schizophrénie et autres symptômes psychotiques, probablement du fait de leur point commun tant sur le plan structural que physiologique avec le L.S.D, vis à vis du récepteur 5-HT2. Le présent travail se propose de faire le point sur la composition et les propriétés du venin de crapaud, ses prétendues vertus hallucinogènes et aphrodisiaques, ce que l'on sait actuellement de ses effets sur l'homme et des risques d'intoxication. Historiquement les crapauds Bufo ont été extrêmement importants pour différentes cultures à travers le monde, durant des millénaires. Ils semblent aujourd'hui susceptibles de nous aider à comprendre et peut-être même un jour à diagnostiquer la survenue de maladies aussi déroutantes que la schizophrénie ou l'autisme et même qui sait, à les guérir. Diverses publications font état de l'usage de ces sécrétions par ingestion ou par inhalation pour leurs effets psychoactifs aux Etats-Unis et en Australie. Cet usage ne semble pas encore répandu en France. On peut souhaiter que le venin de Bufo ne prenne jamais le relais des drogues existantes et qu'au contraire, on puisse y découvrir d'autres molécules d'intérêt thérapeutique. Bufotenin (5-hydroxy-N,N-dimethyltryptamine) is a tryptamine alkaloid, such as serotonin, N-methylserotonin, 5- methoxy-N-methylserotonin and melatonin, widely distributed in the leguminosae family and commonly found in a number of vertebrate as mammals and in many amphibian groups around the world. In human, these molecules show potent psychotropic properties an are usually associated to temporary mental disorders and brain deseases such as schizophrenia and other psychotic symptoms, probably due to their similar physiological and structural features to LSD in the 5HT2 receptor. The present study investigates the properties of toad venom, its hallucinogenic and aphrodisiac alleged properties, what we know about its psychedelic effects and the toxicological hazards for humans. Some papers report the use of toad venom by ingestion or by sniffing in the United States and in Australia. This practice is not yet expanded in France. It is wished that toad venom doesn t take the relay to existent drugs, but on the opposite, it could be useful to discover other therapeutical interests.

Anger Jean-Pierre; Kintz Pascal

2008-01-01

170

Thermodynamic analysis of nonelectrolyte permeation across the toad urinary bladder.  

UK PubMed Central (United Kingdom)

Permeability coefficients (P's) and apparent activation energies (Ealpha's) for nonelectrolyte permeation across the toad urinary bladder have been analyzed in terms of the thermodynamics of partition between membrane lipids and water. Particular attention has been paid to the contributions made by -CH2- and -OH groups: on the average, the addition of one -CH2- group to a molecule increases P fourfold, while the addition of one -OH group reduces P 500-fold. Using these changes in P, we have calculated the incremental free energies (delta delta F), enthalpies (delta delta H), and entropies (delta delta S) for partition, hydration, and solution in membrane lipids. The results for toad bladder have been compared and contrasted with those extracted from the literature for red blood cells, lecithin liposomes, and bulk phase lipid solvents. The partition of -CH2- groups into toad bladder and red cell membranes is dominated by entropy effects, i.e., a decrease in entropy of the aqueous phase that "pushes" the group out of water, and an increase in entropy of the membrane lipid that "pulls" the group into the membrane. This process resembles that in "frozen" liposome membranes. In "melted" liposomes and bulk lipid solvents the free energy of solution in the lipid is controlled by enthalpy of solution. PArtition of -OH groups in all systems is governed by hydrogen bonding between the -OH group and water. However, the solution of the -OH group in the toad bladder membranes is complex, and processes such as dimer and tetramer formation in the lipid phase may be involved. The results presented in this and the previous paper are discussed in terms of the structure of phospholipid bilayer membranes. Attention is drawn to the possible role of structural defects in the quasi-crystalline structure of the lipid (so-called 2 gl klinks) in the permeation of small molecules such as water, urea, methanol and acetamide.

Wright EM; Bindslev N

1976-11-01

171

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

Science.gov (United States)

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

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

2011-01-01

172

A new species of Bufo Laurenti (Anura, Bufonidae) from northeastern Brazil  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english A new species of bufonid load, Bufo jimi sp. nov., is described from Maracás and Itagibá, State of Bahia, Brazil. This species shows close relationships to B. paracnemis Lutz, 1925 by sharing the presence of tibial glands and the paratoid glands shape. The new species is a member of the Bufo marinus-group, and is characlerized by having well-defined glands in most part of dorsal faceof the forearms, in the extcrn side of the feet and in both sides of cloacal region.

Stevaux, Maria Nazaré

2002-07-01

173

A new species of Bufo Laurenti (Anura, Bufonidae) from northeastern Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available A new species of bufonid load, Bufo jimi sp. nov., is described from Maracás and Itagibá, State of Bahia, Brazil. This species shows close relationships to B. paracnemis Lutz, 1925 by sharing the presence of tibial glands and the paratoid glands shape. The new species is a member of the Bufo marinus-group, and is characlerized by having well-defined glands in most part of dorsal faceof the forearms, in the extcrn side of the feet and in both sides of cloacal region.

Maria Nazaré Stevaux

2002-01-01

174

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

UK PubMed Central (United Kingdom)

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

Price-Rees SJ; Brown GP; Shine R

2012-03-01

175

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

Science.gov (United States)

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

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

2012-01-25

176

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

Energy Technology Data Exchange (ETDEWEB)

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

Gauna, L.; Caballero de Castro, A.; Chifflet de Llamas, M.; Pechen de D' Angelo, A.M. (Univ. Nacional del Comahue, Buenos Aires (Argentina))

1991-04-01

177

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

UK PubMed Central (United Kingdom)

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

Crossland MR; Haramura T; Salim AA; Capon RJ; Shine R

2012-09-01

178

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

Science.gov (United States)

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

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

2012-06-13

179

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

180

The envelopes of amphibian oocytes: physiological modifications in Bufo arenarum  

Directory of Open Access Journals (Sweden)

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

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

2003-01-01

 
 
 
 
181

Cannibalistic behaviour of Epidalea (Bufo) viridis tadpoles in an urban breeding habitat  

Directory of Open Access Journals (Sweden)

Full Text Available Larvae of Epidalea (Bufo) viridis showing cannibalistic behaviour were observed in June 2006 in a pond from Oradea city, western Romania. This is the first record of such behaviour in the country and probably was induced by the scarcity of food and the high density of larvae present in the rapidly drying pond in which they occurred.

Éva-Hajnalka KOVÁCS; István SAS

2009-01-01

182

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

2012-05-13

183

Antagonism Between Chlorpyrifos and Flaxedil in Toad and Earthworm Neuromuscular Transmission  

Directory of Open Access Journals (Sweden)

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; Amauri B. Bartoszeck; Samir A. Madeira; Charles I. Abramson

2006-01-01

184

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

Directory of Open Access Journals (Sweden)

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; Nilda E. Fink; Alfredo Salibián

2007-01-01

185

ELECTRICAL EXCITABILITY OF ISOLATED FROG SKIN AND TOAD BLADDER.  

UK PubMed Central (United Kingdom)

When current of proper polarity and sufficient intensity is passed across isolated frog skin or toad bladder, an action potential of about 200 mv and 10 msec. duration with a sharp threshold and refractory period of several seconds' duration is elicited. Interruption of current during the action potential abolishes the response, and, as shown by appropriate bridge measurements, this occurs because the action potential results from resistance variations during the current flow. The ionic composition of the medium bathing the frog skin was varied, and it was found that the response is relatively insensitive to changes in the solution bathing the inner surface, but rapidly and reversibly affected by changes in the outer solution, particularly by replacement of sodium with potassium and by variations of calcium concentration. It was also observed that the resistance of the skin and action potential across it are reversibly altered by metabolic inhibitors and that these alterations occur independently of any changes in the intrinsic EMF of the system. From the finding that the action potential across frog skin and toad bladder results from a time-variant resistance, it is argued that this same phenomenon can be the basis of electrical excitability in general. This would attribute physical significance to the equivalent circuit commonly employed to represent the plasma membrane; i.e., the plasma membrane would be a mosaic structure of spatially separate permselective regions.

FINKELSTEIN A

1964-01-01

186

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

UK PubMed Central (United Kingdom)

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

Sánchez Riera A; Daud A; Gallo A; Genta S; Aybar M; Sánchez S

2003-04-01

187

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

Science.gov (United States)

Amphibians respond to microbial infection through cellular and humoral defense mechanisms such as antimicrobial protein secretion. Most humoral defense proteins are synthetized in the skin. In this study we isolated two beta-galactoside-binding lectins with molecular weights of 50 and 56 KDa from the skin of Bufo arenarum. These lectins have significant hemagglutination activity against trypsinized rabbit erythrocytes, which was inhibited by galactose-containing saccharides. They are water-soluble and independent of the presence of calcium. The antimicrobial analysis for each lectin was performed. At mumolar concentration lectins show strong bacteriostatic activity against Gram negative bacteria (Escherichia coli K12 4100 and wild strains of Escherichia coli and Proteus morganii) and Gram positive bacteria (Enterococcus faecalis). The antibacterial activity of these lectins may provide an effective defense against invading microbes in the amphibian Bufo arenarum. PMID:12847913

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

2003-04-01

188

Antibacterial activity of lactose-binding lectins from Bufo arenarum skin  

Directory of Open Access Journals (Sweden)

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

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

2003-01-01

189

Antibacterial activity of lactose-binding lectins from Bufo arenarum skin  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Amphibians respond to microbial infection through cellular and humoral defense mechanisms such as antimicrobial protein secretion. Most humoral defense proteins are synthetized in the skin. In this study we isolated two b-galactoside-binding lectins with molecular weights of 50 and 56 KDa from the skin of Bufo arenarum. These lectins have significant hemagglutination activity against trypsinized rabbit erythrocytes, which was inhibited by galactose-containing saccharides. (more) 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.

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

2003-04-01

190

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

UK PubMed Central (United Kingdom)

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

Narayan EJ; Cockrem JF; Hero JM

2011-09-01

191

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

Science.gov (United States)

Urinary corticosterone metabolite responses to capture have recently been shown for the first time in amphibians, and in the present study urinary corticosterone metabolite responses to capture and to confinement in captivity were measured in adult cane toads (Rhinella marina) in Queensland, Australia. An adrenocorticotropic hormone (ACTH) challenge was used to provide a biological validation for urinary corticosterone metabolite concentrations measured by radioimmunoassay (RIA). Urinary corticosterone metabolite increased 1-2 days after ACTH but not saline injection and then returned to initial values, indicating that the RIA could detect changes in corticosterone secretion in toads. Urinary corticosterone metabolite responses to short-term capture and restraint in plastic bags were first apparent 2h after capture of wild toads. Toads held communally in captivity for 5 days had elevated urinary corticosterone metabolite concentrations. Mean corticosterone concentrations declined significantly after a further 7 days in individual housing chambers. There was no sex difference in urinary corticosterone metabolite responses of toads to ACTH challenge, short-term capture or captivity. The relative amount of variation in the mean corticosterone responses was quantified by calculating coefficients of variation (CV) for each mean corticosterone response. Mean corticosterone at 0 min was more variable for captive toads than wild toads. Furthermore, initial corticosterone concentrations (0 min) were more variable than concentrations during the ACTH challenge, short-term capture and captivity. There was little change in the amount of variation of mean corticosterone levels between male and female toads with increasing time in captivity (12-29 days). This study has shown individual corticosterone responses of amphibians for the first-time, and has provided a novel method for quantifying the relative amount of variation in amphibian corticosterone responses. PMID:21756910

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

2011-07-02

192

Contribution to the study of immune hemolysis by toad complement  

Scientific Electronic Library Online (English)

Full Text Available 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 (more) 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. 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 syst (more) em, 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.

1982-09-01

193

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

UK PubMed Central (United Kingdom)

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

Toledo LF; Ribeiro RS

2009-09-01

194

Effect of Corn Oil on Liver Glycogen Content and Blood Glucose-6-phosphatase Dehydrogenase in Toads Treated with DMBA  

Directory of Open Access Journals (Sweden)

Full Text Available Environmental factors play an important role in the etiology of several types of cancer, this discovery has led to a great deal of interest in the role of diet in cancer etiology. Fed the Egyptian toad with 0.5 ml corn oil and 0.2 mg DMBA toad/3, 3 times/week increased the incidence of liver tumor (22 out of 50 cases) in comparison with toads treated with DMBA alone (16 out of 50 cases). On the ultrastructural level, corn oil increased (a) the depletion of glycogen, (b) accumulation of fat and lysosomes in toad liver tumor. The biochemical data indicated that glucose-6 phosphatase dehydrogenase in the blood, acid and alkaline phosphatase enzymes activities were increased in serum of toads treated with DMBA and corn oil than animals treated with DMBA alone.

N.E. Abdelmeguid; I. A. Sadek; J. M. Sorour; A. A. Attia

2000-01-01

195

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

196

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

197

Arsenic species and uptake in amphibians (Rana clamitans and Bufo americanus).  

UK PubMed Central (United Kingdom)

Total arsenic concentrations and the chemical form, or species, of arsenic were determined in amphibians (Rana clamitans and Bufo americanus) collected from a site with elevated arsenic concentrations in Nova Scotia, Canada. Frog legs had significantly elevated total arsenic concentrations at a contaminated site when compared with a nearby background site and a calculation of the estimated daily intake rates of arsenic indicates that both diet (invertebrate intake) and water absorption are important sources of arsenic for these adult organisms. Body burdens of tetramethylarsonium were similar for both the contaminated and background site, with up to 50% of the total arsenic contained in frog legs in the form of the tetramethylarsonium ion.

Moriarty MM; Koch I; Reimer KJ

2013-08-01

198

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

UK PubMed Central (United Kingdom)

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

Crossland MR; Shine R

2012-04-01

199

Propagation of natural toad calls in a Mediterranean terrestrial environment.  

UK PubMed Central (United Kingdom)

Propagation patterns of animal acoustic signals provide insights into the evolution of signal design to convey signaler's information to potential recipients. However, propagation properties of vertebrate calls have been rarely studied using natural calls from individuals; instead playback calls broadcast through loudspeakers have been used extensively, a procedure that may involve acoustical and physical features differing from natural sounds. Measurements of the transmission characteristics of natural advertisement calls, which are simple tonal sounds, of the Iberian midwife toad, Alytes cisternasii, were carried out, and the results were compared with previously published results broadcasting recorded calls of the same species. Measurements of sound pressure level (SPL) of calls from individual male A. cisternasii revealed that the call amplitude decreases at distances of 1-8 m from the source at rates averaging 1-5 dB above spherical transmission loss in an omni-directional pattern. A comparison between SPLs of natural calls in the current study and of playback calls from a previous study showed that patterns of propagation did not differ in average values, but variance was significantly higher for natural calls. Results suggest that using broadcast signals for transmission experiments may result in a simplification of the conditions in which actual animals communicate in nature.

Penna M; Llusia D; Márquez R

2012-12-01

200

Propagation of natural toad calls in a Mediterranean terrestrial environment.  

Science.gov (United States)

Propagation patterns of animal acoustic signals provide insights into the evolution of signal design to convey signaler's information to potential recipients. However, propagation properties of vertebrate calls have been rarely studied using natural calls from individuals; instead playback calls broadcast through loudspeakers have been used extensively, a procedure that may involve acoustical and physical features differing from natural sounds. Measurements of the transmission characteristics of natural advertisement calls, which are simple tonal sounds, of the Iberian midwife toad, Alytes cisternasii, were carried out, and the results were compared with previously published results broadcasting recorded calls of the same species. Measurements of sound pressure level (SPL) of calls from individual male A. cisternasii revealed that the call amplitude decreases at distances of 1-8 m from the source at rates averaging 1-5 dB above spherical transmission loss in an omni-directional pattern. A comparison between SPLs of natural calls in the current study and of playback calls from a previous study showed that patterns of propagation did not differ in average values, but variance was significantly higher for natural calls. Results suggest that using broadcast signals for transmission experiments may result in a simplification of the conditions in which actual animals communicate in nature. PMID:23231131

Penna, Mario; Llusia, Diego; Márquez, R

2012-12-01

 
 
 
 
201

Anticipatory motor patterns limit muscle stretch during landing in toads.  

UK PubMed Central (United Kingdom)

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 E; Abbott EM

2013-02-01

202

Real-time OCT for study of cornea of living Indian frogs and toads  

Directory of Open Access Journals (Sweden)

Full Text Available A high-speed Optical Coherence Tomography (OCT) system based on single mode fiber which can capture eightimages per second was used to acquire OCT images of the eyes of Indian frogs and toads. The axial resolution of theset up was estimated to be 18 ?m. With these OCT images, the ocular parameters, viz. corneal thickness, anteriorchamber depth and anterior chamber angle were estimated. The thickness of the cornea of frog and toad is found tobe 136.12 ?m and 100.66 ?m respectively. Measurement of corneal thickness is needed in many physiological andclinical studies and is helpful in diagnosis of several corneal disorders.

S.Kumari

2011-01-01

203

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; Eduardo R. Soto; Claudio Correa; Alberto Veloso; Eliseo Vergara; Michel Sallaberry; Patricia Iturra

2004-01-01

204

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 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 información morfométrica y genética fue analizada en función de la procedencia geográfica. La correlación entre diferenciación genética y morfométrica fue analiz (more) ada 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 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 (more) 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

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

2004-09-01

205

Antagonism Between Chlorpyrifos and Flaxedil in Toad and Earthworm Neuromuscular Transmission  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 prep...

Yong-Chiang Chang; Amauri B. Bartoszeck; Samir A. Madeira; Charles I. Abramson

206

The action of local anesthetics on myelin structure and nerve conduction in toad sciatic nerve.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

X-ray scattering and electrophysiological experiments were performed on toad sciatic nerves in the presence of local anesthetics. In vitro experiments were performed on dissected nerves superfused with Ringer's solutions containing procaine, lidocaine, tetracaine, or dibucaine. In vivo experiments w...

Mateu, L; Morán, O; Padrón, R; Borgo, M; Vonasek, E; Márquez, G; Luzzati, V

207

The functionality of female reciprocal calls in the Iberian midwife toad (Alytes cisternasii): female-female acoustic competition?  

Science.gov (United States)

Female midwife toads (genus Alytes) emit highly variable reciprocal calls of unclear function prior to and during courtship. In some species, female-female competition, expressed as physical fighting, has been reported. Males of Majorcan midwife toads (Alytes muletensis) show phonotactic response to female calls, and females of Iberian midwife toads (Alytes cisternasii) respond differently according to the male call characteristics. In this study, I test the hypothesis of female-female acoustic competition as an additional function of female reciprocal calls. Playback tests indicate that female calls are not clearly involved in female acoustic competition in the Iberian midwife toad, therefore female calls could be directed at males rather than towards competitive females.

Bosch, Jaime

2002-11-01

208

ALIMENTACIÓN DE BUFO MARINUS (LINNAEUS, 1758) (BUFONIDAE: ANURA), EN UNA LOCALIDAD DE SUCRE, COLOMBIA  

Directory of Open Access Journals (Sweden)

Full Text Available Se realizaron recolectas nocturnas de Bufo marinus en una localidad del departamento de Sucre. Se recolectaron 197 ejemplares, de los cuales 128 fueron hembras y 69 machos. Los ejemplares fueron medidos y pesados y se les practicó una disección para extraer el estómago y determinar aspectos cualitativos (tipo de presas) y cuantitativos (número y tamaño de presas). Insectos del orden Hymenoptera fueron las presas de mayor importancia. Los individuos de mayor tamaño ingieren presas más grandes y en menor cantidad mientras que los de menor talla, presas pequeñas, pero en mayor cantidad. La proporción del peso del contenido estomacal en relación con el peso corporal, tanto para hembras como para machos fue similar (6%). Esta especie no parece representar un peligro para la fauna nativa en el departamento de Sucre.

Sampedro Alcides; et al

2011-01-01

209

Study on the alcohol concentration influence on the Bufo heart activity  

UK PubMed Central (United Kingdom)

Using three methods(soaking hearts, injecting sinus vein,injecting stomach),diff erent concentration and volume of ethyl alcohol were added according to the weig ht of Bufo linnaeus,and then recorded the heart pulsing diagram by the two p hysiology recording instrument. The result showed that the ethyl alcohol obvious ly affects the heart rate and contract range. The contract rate of cardiac muscl e was improved gradually and the contract range widened while increasing the con centration of ethyl alcohol. However, when the concentration got its maximum, the heart activity was exhausted gradually and the range descends gradually. The h eart rate slowed down gradually while increasing the alcohol concentration a bit, and then the heart stopped at last.

Wang Suying; Zhang Qifei

2003-01-01

210

Molecular Cloning and Characterization of Cystatin, a Cysteine Protease Inhibitor, from Bufo melanostictus.  

UK PubMed Central (United Kingdom)

Cystatins are efficient inhibitors of papain-like cysteine proteinases, and they serve various important physiological functions. In this study, a novel cystatin, Cystatin-X, was cloned from a cDNA library of the skin of Bufo melanostictus. The single nonglycosylated polypeptide chain of Cystatin-X consisted of 102 amino acid residues, including seven cysteines. Evolutionary analysis indicated that Cystatin-X can be grouped with family 1 cystatins. It contains cystatin-conserved motifs known to interact with the active site of cysteine proteinases. Recombinant Cystatin-X expressed and purified from Escherichia coli exhibited obvious inhibitory activity against cathepsin B. rCystatin-X at a concentration of 8 µM inhibited nearly 80% of cathepsin B activity within 15 s, and about 90% of cathepsin B activity within 15 min. The Cystatin-X identified in this study can play an important role in host immunity and in the medical effect of B. melanostictus.

Liu W; Ji S; Zhang AM; Han Q; Feng Y; Song Y

2013-10-01

211

Alimentación y fecundidad de Bufo variegatus (Anura: Bufonidae) en Santa Cruz, Argentina  

Directory of Open Access Journals (Sweden)

Full Text Available Se describe la alimentación de una población de Bufo variegatus procedente de la región de Lago del Desierto, provincia de Santa Cruz, Argentina. De los 11 ítems presa identificados, los más consumidos por los adultos (tanto machos como hembras) fueron los coleópteros. En los machos la segunda categoría presa mas importante en la contribución a la dieta fueron los ácaros, mientras que en las hembras las hormigas y las larvas de insectos siguieron en importancia al consumo de coleópteros. En los especímenes juveniles, los ácaros fueron las presas más consumidas, quedando los coleópteros en segundo lugar en importancia relativa. Se demuestra la existencia de una correlación positiva significativa entre el volumen de las presas y el tamaño del depredador. Se aportan datos referentes a la fecundidad de B. variegatus y se comprueba la ausencia de correlación entre el tamaño de las hembras grávidas y el número de óvulos maduros. The diet of a population of Bufo variegatus from the region of Lago del Desierto, Santa Cruz province, Argentina, is described. Of the 11 prey items identified, Coleoptera was the most consumed prey both for males and females. In males, the second most important prey was Acarii, while in females they were the ants and insect larvae. Acarii was the most consumed prey for juveniles, followed by Coleoptera. A significant positive correlation was found between prey volume and predator body size. Fecundity information for B. variegwus is given, and a lack of correlation between snout-vent length of mature females and ovarian egg complement is demonstrated.

Rappi, Guillermina E.; Fernández, Sandra R.; Basso, Néstor G.

2000-01-01

212

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

Directory of Open Access Journals (Sweden)

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

Jorge Herkovits; Cristina Silvia Pérez-Coll

2007-01-01

213

Notes on the biology of Amblyomma dissimile Kock, 1844 (Acari: Ixodida) on Bufo marinus (Linnaeus, 1758) from Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available Amblyomma dissimile is a common ectoparasite of cold blooded animals and is an accidental ectoparasite of some wild mammals. Details of the biology of specimens from the State of Amapá were studied in the laboratory in a humidity chamber at an average environmental temperature of 19.5 °C, using Bufo marinus as host for the time in Brazil. We also report the first record of this species in the State of Minas Gerais.

Teresinha Tizu Sato Schumaker; Darci Moraes Barros

1994-01-01

214

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

International Nuclear Information System (INIS)

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

1981-01-01

215

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

Directory of Open Access Journals (Sweden)

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

J. Herkovits; J. L. D´Eramo; O. Fridman

2006-01-01

216

Multisensory interaction in the torus semicircularis of the clawed toad Xenopus laevis.  

UK PubMed Central (United Kingdom)

Interactions between the lateral-line, general somatosensory and auditory system were studied using field potential analysis and single unit recordings in the torus semicircularis of the clawed toad Xenopus laevis. As a response to paired stimuli (electric shocks applied to the peripheral nerves or acoustic clicks), in all systems a reduction of the second evoked potential occurred for intervals of up to 5 s. Following consecutive stimulation of two different systems, the amplitude of the second evoked potential was also reduced, indicating mutual interaction of different systems. Single unit recordings revealed the existence of both inhibitory and excitatory interaction between different modalities.

Zittlau KE; Claas B; Münz H; Görner P

1985-09-01

217

Multisensory interaction in the torus semicircularis of the clawed toad Xenopus laevis.  

Science.gov (United States)

Interactions between the lateral-line, general somatosensory and auditory system were studied using field potential analysis and single unit recordings in the torus semicircularis of the clawed toad Xenopus laevis. As a response to paired stimuli (electric shocks applied to the peripheral nerves or acoustic clicks), in all systems a reduction of the second evoked potential occurred for intervals of up to 5 s. Following consecutive stimulation of two different systems, the amplitude of the second evoked potential was also reduced, indicating mutual interaction of different systems. Single unit recordings revealed the existence of both inhibitory and excitatory interaction between different modalities. PMID:4058802

Zittlau, K E; Claas, B; Münz, H; Görner, P

1985-09-16

218

The effect of three anaesthetic protocols on the stress response in cane toads (Rhinella marina).  

UK PubMed Central (United Kingdom)

OBJECTIVE: Three anaesthetics (MS222, clove oil and a mixture of ketamine/diazepam) were administered to cane toads to determine their effect on the hypothalamic-pituitary-adrenal (HPA) axis. Time to induction and recovery and any adverse events were also evaluated. STUDY DESIGN: Prospective randomized experimental trial. ANIMALS: Thirty adult male cane toads (Rhinella marina) with body mass ranging between 130 and 250 g were captured from the field. METHODS: Three groups of 10 toads were anaesthetized with ketamine (200 mg kg(-1) ) and diazepam (0.2 mg kg(-1) ) by intramuscular injection, MS222 (3 g L(-1) ) or clove-oil (0.3 mL L(-1) ) both by immersion. Blood samples were collected to determine plasma corticosterone concentrations. Induction and recovery time were recorded in each treatment. After full recovery animals were euthanized and a complete post-mortem examination was performed. RESULTS: Significant differences were found in the activation of the HPA axis and in the times of induction and recovery between treatments (p < 0.001). Animals anaesthetized with clove-oil had the highest levels of corticosterone in plasma (42.5 ± 21.6 ng mL(-1) ). No differences were found between ketamine/diazepam (15.0 ± 13.3 ng mL(-1) ) and MS222 (22.0 ± 13.6 ng mL(-1) ) groups. The mean ± SD induction (minutes) and recovery (hours) times respectively were; ketamine/diazepam 66.5 ± 11 and 8 ± 3, clove oil 39 ± 12 and 7.6 ± 3, and MS222 42.5 ± 11 and 1.5 ± 0.5. Clove oil exposure had 30% mortality. Death followed a period of respiratory distress with changes consistent with non-cardiogenic oedema observed at post-mortem examination. CONCLUSIONS AND CLINICAL RELEVANCE: Based on shorter induction and recovery times and minimal activation of HPA, MS222 is the anaesthetic of choice in cane toads. If it is not possible to use immersion methods of anaesthesia, ketamine/diazepam can be used but induction and recovery times are prolonged. Clove oil had unacceptable mortality in this study and should be used with extreme caution.

Hernández SE; Sernia C; Bradley AJ

2012-11-01

219

Development of 22 Polymorphic Microsatellite Loci for the Critically Endangered Morato’s Digger Toad, Proceratophrys moratoi  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Morato’s digger toad (Proceratophrys moratoi) inhabits Brazilian moist savannas and is critically endangered due to its very limited geographic distribution, reduced number of isolated populations, and evidence of population decline and local extinctions. With the objective of providing tools fo...

Maurício Papa Arruda; William Pinheiro Costa; Carla Cristina Silva; Shirlei Maria Recco Pimentel

220

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

 
 
 
 
221

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

2011-01-01

222

Ba2+-inhibitable /sup 86/Rb+ fluxes across membranes of vesicles from toad urinary bladder  

Energy Technology Data Exchange (ETDEWEB)

/sup 86/Rb+ fluxes have been measured in suspensions of vesicles prepared from the epithelium of toad urinary bladder. A readily measurable barium-sensitive, ouabain-insensitive component has been identified; the concentration of external Ba2+ required for half-maximal inhibition was 0.6 mM. The effects of externally added cations on /sup 86/Rb+ influx and efflux have established that this pathway is conductive, with a selectivity for K+, Rb+ and Cs+ over Na+ and Li+. The Rb+ uptake is inversely dependent on external pH, but not significantly affected by internal Ca2+ or external amiloride, quinine, quinidine or lidocaine. It is likely, albeit not yet certain, that the conductive Rb+ pathway is incorporated in basolateral vesicles oriented right-side-out. It is also not yet clear whether this pathway comprises the principle basolateral K+ channel in vivo, and that its properties have been unchanged during the preparative procedures. Subject to these caveats, the data suggest that the inhibition by quinidine of Na+ transport across toad bladder does not arise primarily from membrane depolarization produced by a direct blockage of the basolateral channels. It now seems more likely that the quinidine-induced elevation of intracellular Ca2+ activity directly blocks apical Na+ entry.

Garty, H.; Civan, M.M.

1987-01-01

223

Ba2+-inhibitable 86Rb+ fluxes across membranes of vesicles from toad urinary bladder  

International Nuclear Information System (INIS)

86Rb+ fluxes have been measured in suspensions of vesicles prepared from the epithelium of toad urinary bladder. A readily measurable barium-sensitive, ouabain-insensitive component has been identified; the concentration of external Ba2+ required for half-maximal inhibition was 0.6 mM. The effects of externally added cations on 86Rb+ influx and efflux have established that this pathway is conductive, with a selectivity for K+, Rb+ and Cs+ over Na+ and Li+. The Rb+ uptake is inversely dependent on external pH, but not significantly affected by internal Ca2+ or external amiloride, quinine, quinidine or lidocaine. It is likely, albeit not yet certain, that the conductive Rb+ pathway is incorporated in basolateral vesicles oriented right-side-out. It is also not yet clear whether this pathway comprises the principle basolateral K+ channel in vivo, and that its properties have been unchanged during the preparative procedures. Subject to these caveats, the data suggest that the inhibition by quinidine of Na+ transport across toad bladder does not arise primarily from membrane depolarization produced by a direct blockage of the basolateral channels. It now seems more likely that the quinidine-induced elevation of intracellular Ca2+ activity directly blocks apical Na+ entry.

1987-01-01

224

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

UK PubMed Central (United Kingdom)

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

Pizzatto L; Kelehear C; Shine R

2013-08-01

225

Community structure of helminth parasites of the "Cururu" toad, Rhinella icterica (Anura: Bufonidae) from southern Brazil.  

UK PubMed Central (United Kingdom)

Sixty specimens of the "cururu" toad, Rhinella icterica (Spix 1824) (Bufonidae), were collected in Campo Belo do Sul, State of Santa Catarina, Brazil, between May 2009 and January 2011, and were examined for the presence of helminth parasites. Nine species of adult helminths were found: Catadiscus cohni, Rudolphitrema rudolphii, Cylindrotaenia sp., Rhabdias fuelleborni, Strongyloides sp., Cosmocerca rara, Cosmocerca brasiliensis, Aplectana elenae, and Oxyascaris sp., in addition to an unidentified adult nematode species. Females of cosmocercid nematodes, proteocephalan plerocercoid, and acanthocephalan cystacanth were found but not identified for lack absolute of taxonomic characters. The sex of the anurans had no influence on prevalence, abundance, and richness of helminth species. Length and body mass of hosts did not influence the prevalence and richness of helminths, while the abundance of R. fuelleborni was significantly correlated with both parameters.

Dos Santos VG; Amato SB; Borges-Martins M

2013-03-01

226

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

UK PubMed Central (United Kingdom)

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.

Zhang GB; Wang MY; Zheng JQ; Tang XC

1994-03-01

227

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

UK PubMed Central (United Kingdom)

The Cl- -current through toad skin epithelium depends on the potential in a way consistent with a potential-controlled Cl- permeability. Computer analysis of the Koefoed-Johnsen Ussing two-membrane model provided with constant membrane permeabilities indicates that the voltage- and time-dependent currents are not caused by a trivial Goldmand-type rectification and ion redistributions following transepithelial potential pertubations. Extended with a dynamic Cl- permeability in the apical membrane according to a Hodgkin-Huxley kinetic scheme, the model predicts voltage clamp data which closely resemble experimental observations. This extension of the classic frog skin model implies that the Cl- permeability is activated by a voltage change caused by the inward Na+ current through the apical membrane.

Larsen EH; Rasmussen BE

1983-03-01

228

Drugs activating G proteins disturb cycling of ADH-dependent water channels in toad urinary bladder.  

UK PubMed Central (United Kingdom)

In the toad urinary bladder, antidiuretic hormone (ADH)-mediated changes in water permeability depend on exocytic insertion and endocytic retrieval of water channels into and from the apical membrane, respectively. Because GTP-binding proteins (G proteins) are well-recognized regulators of vesicular trafficking throughout the cell, we tested the hypothesis that drugs interfering with G protein would modify the hydrosmotic response to ADH and the ADH-regulated formation of endosomes, as assessed by luminal incorporation of a fluid-phase marker [fluorescein isothiocyanate (FITC)-dextran, 70 kDa]. Mastoparan (4 microM) and compound 48/80 (poly-p-methoxyphenylethylmethylamine; 50 micrograms/ml), added to the luminal side of the toad urinary bladder, as well as AlF3 added to the serosal side (400 microM), inhibited ADH- and 8-bromoadenosine 3',5'-cyclic monophosphate-induced transepithelial water flow by > 50% and simultaneously enhanced cellular incorporation of FITC-dextran by > 200%. The pattern of FITC-dextran uptake observed using fluorescence microscopy both in scraped cells and in the intact bladder was granular, suggesting fluid-phase endocytosis. Mastoparan and AlF3, which are both probes of G proteins, increased FITC-dextran uptake only in the presence of ADH and a transepithelial osmotic gradient, i.e., under conditions where water channel-carrying endosomes presumably cycle. Therefore, we suggest that the ADH-dependent cycling of water channels could be controlled by one or more G proteins associated with the apical membrane and/or the water channel-carrying vesicles.

Boom A; Flamion B; Abramow M; Beauwens R

1995-08-01

229

Reversible conduction block in isolated toad sciatic nerve by emulsified isoflurane.  

UK PubMed Central (United Kingdom)

BACKGROUND: Studies have shown that the local use of volatile anesthetics can produce local anesthetic effects. We designed this study to evaluate the characteristics of nerve conduction block of emulsified isoflurane (EI) and compare its nerve blockade with 1%lidocaine, by measuring compound nerve action potential (CNAP) parameters in isolated toad sciatic nerve. METHODS: One hundred isolated toad sciatic nerves were selected and randomly assigned to 10 groups of 10 each, administered 2% to 8% EI (v/v) (EI(8) group, etc.), 1% lidocaine, 30% Intralipid(R) (Huarui Pharmacy, Wuxi, Jiangsu, China), and Ringer solution (RS) for 10 minutes, respectively. All nerves were then washed and soaked with RS for 10 minutes and 30 minutes. The nerve conduction block effect was represented by CNAP parameters that were recorded by an extracellular recording technique per minute. RESULTS: The results showed that the negative amplitudes of CNAP were decreased by EI and lidocaine (P < 0.05), and the conduction velocities of CNAP were also decreased at some time points (D7-W3) (P < 0.05). After RS washing, the 2 parameters recovered gradually. The changes in the 2 parameters induced by EI had slower onset rates and faster recoveries than those produced by lidocaine (7 minutes vs 1 minute and 9 minutes vs 30 minutes). The nerve blockade induced by EI was dose dependent (P < 0.05), and the half maximal inhibition concentration of EI was 5.46%. CONCLUSIONS: EI produced completely reversible and dose-dependent nerve conduction inhibition, which had slower onset and faster recovery compared with those produced by lidocaine.

Li Z; Yang J; Liu J; Gong CY; Gan J; Zhang X; Luo WJ; Li GH

2010-04-01

230

Effects of seasonal aridity on the ecology and behaviour of invasive cane toads in the Australian wet–dry tropics  

UK PubMed Central (United Kingdom)

1.?Measuring the costs imposed by specific environmental challenges is difficult, because organisms adapt in ways that reduce those costs. Invasive species provide an opportunity to quantify environmental impacts before organisms can make adaptive changes. 2.?The native range of cane toads (Rhinella marina) lies within the wet neotropics; although part of this range experiences seasonal drought, many of the places recently invaded by this large anuran species are much more arid. 3.?Five years’ fieldwork from a seasonally arid site in the Australian wet–dry tropics shows strong seasonal shifts in the toads’ (i) population structure, reflecting seasonality in breeding and recruitment; (ii) adult morphology (secondary sexual characteristics in males); (iii) growth rates; (iv) energy balance; (v) spatial ecology (philopatry, dispersal rates) and (vi) adult mortality rates. 4.?Some of these patterns accord with intuition: for example, wet?season conditions resulted in higher rates of growth, reproduction and movement, better body condition and more pronounced secondary sexual characteristics. However, seasonal patterns for other traits were non?intuitive: for example, neither hematocrit levels (reflecting hydration state) nor corticosterone levels (reflecting stress) showed significant seasonal variation, and mortality rates were higher in the wet season than the dry season. 5.?The toads’ ability to flexibly adjust their behaviour and ecology to local hydric conditions has allowed them to thrive even under climatic conditions that preclude activity, feeding and reproduction for most of the year.

Brown GP; Kelehear C; Shine R

2011-12-01

231

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

UK PubMed Central (United Kingdom)

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

Li J; Guo X; Chen D; Wang Y

2013-06-01

232

[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

233

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

UK PubMed Central (United Kingdom)

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

Ramsay ZJ; Laberge F

2013-07-01

234

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

Scientific Electronic Library Online (English)

Full Text Available 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, long, narrow, spatulate, with lateral borders parallel and rounded tip; in profile, long, strongly acute; parotoid glands large, rounded; tympanum concealed; dorsum rugose, wi (more) th 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

2012-08-01

235

Angiotensin-(1-7) increases osmotic water permeability in isolated toad skin  

Directory of Open Access Journals (Sweden)

Full Text Available Angiotensin-(1-7) (Ang-(1-7)) increased osmotic water permeability in the isolated toad skin, a tissue with functional properties similar to those of the distal mammalian nephron. Concentrations of 0.1 to 10 µM were effective, with a peak at 20 min. This effect was similar in magnitude to that of frog skin angiotensin II (Ang II) and oxytocin but lower than that of human Ang II and arginine-vasotocin. The AT2 angiotensin receptor antagonist PD 123319 (1.0 µM) fully inhibited the response to 0.1 µM Ang-(1-7) but had no effect on the response to Ang II at the same concentration. The specific receptor antagonist of Ang-(1-7), A-779, was ineffective in blocking the response to Ang-(1-7) and to frog skin Ang II. The AT1 receptor subtype antagonist losartan, which blocked the response to frog skin Ang II, was ineffective in blocking the response to Ang-(1-7). The present results support the view of an antidiuretic action of Ang-(1-7) in the mammalian nephron.

Santos J.C.; Jerez S.; Peral de Bruno M.; Coviello A.

2000-01-01

236

Angiotensin-(1-7) increases osmotic water permeability in isolated toad skin  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Angiotensin-(1-7) (Ang-(1-7)) increased osmotic water permeability in the isolated toad skin, a tissue with functional properties similar to those of the distal mammalian nephron. Concentrations of 0.1 to 10 µM were effective, with a peak at 20 min. This effect was similar in magnitude to that of frog skin angiotensin II (Ang II) and oxytocin but lower than that of human Ang II and arginine-vasotocin. The AT2 angiotensin receptor antagonist PD 123319 (1.0 µM) fully inhi (more) bited the response to 0.1 µM Ang-(1-7) but had no effect on the response to Ang II at the same concentration. The specific receptor antagonist of Ang-(1-7), A-779, was ineffective in blocking the response to Ang-(1-7) and to frog skin Ang II. The AT1 receptor subtype antagonist losartan, which blocked the response to frog skin Ang II, was ineffective in blocking the response to Ang-(1-7). The present results support the view of an antidiuretic action of Ang-(1-7) in the mammalian nephron.

Santos, J.C.; Jerez, S.; Peral de Bruno, M.; Coviello, A.

2000-09-01

237

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

Science.gov (United States)

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

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

2013-01-18

238

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

UK PubMed Central (United Kingdom)

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

Chen D; Guo X; Li J

2013-03-01

239

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

Science.gov (United States)

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

Chen, Dali; Guo, Xianguang; Li, Jun

2013-03-14

240

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

Directory of Open Access Journals (Sweden)

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

Procopio J.

1997-01-01

 
 
 
 
241

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

242

Mitochondrial DNA variation in the hybridizing fire-bellied toads, Bombina bombina and B. variegata.  

Science.gov (United States)

Using five restriction enzymes, geographical variation of mitochondrial DNA (mtDNA) in Bombina bombina and B. variegata was studied in samples from 20 locations. Each restriction enzyme produced a species-specific fragment pattern. B. bombina haplotypes A and B were closely related to each other. In contrast, haplotypes A and B of B. variegata formed two distinct lineages. A very distinctive haplotype (C) was found in the Carpathian Mountains, whereas two other haplotypes, D and E (differing by a single AvaI site), were present in western Europe and the Balkans, respectively. Populations polymorphic for haplotypes D and E occurred in the central Balkans where the haplotypes could replace each other clinally. mtDNA sequence divergence between B. bombina and B. variegata was estimated as 6.0-8.1% and 4.7-5.2% between type C and types D/E of B. variegata. The latter divergence is contrary to allozyme and morphological data that place the western and Carpathian B. v. variegata together (Nei's D = 0.07) and separate them from the Balkan subspecies B. v. scabra (Nei's D = 0.18). Broad interspecific correlation among morphology, allozymes and mtDNA types in European fire-bellied toads argues that, despite continuous hybridization (interrupted perhaps during Pleistocene glacial maxima), little or no mtDNA introgression between the species has occurred outside the narrow hybrid zones that separate these parapatric species. PMID:10886652

Szymura, J M; Uzzell, T; Spolsky, C

2000-07-01

243

Mitochondrial DNA variation in the hybridizing fire-bellied toads, Bombina bombina and B. variegata.  

UK PubMed Central (United Kingdom)

Using five restriction enzymes, geographical variation of mitochondrial DNA (mtDNA) in Bombina bombina and B. variegata was studied in samples from 20 locations. Each restriction enzyme produced a species-specific fragment pattern. B. bombina haplotypes A and B were closely related to each other. In contrast, haplotypes A and B of B. variegata formed two distinct lineages. A very distinctive haplotype (C) was found in the Carpathian Mountains, whereas two other haplotypes, D and E (differing by a single AvaI site), were present in western Europe and the Balkans, respectively. Populations polymorphic for haplotypes D and E occurred in the central Balkans where the haplotypes could replace each other clinally. mtDNA sequence divergence between B. bombina and B. variegata was estimated as 6.0-8.1% and 4.7-5.2% between type C and types D/E of B. variegata. The latter divergence is contrary to allozyme and morphological data that place the western and Carpathian B. v. variegata together (Nei's D = 0.07) and separate them from the Balkan subspecies B. v. scabra (Nei's D = 0.18). Broad interspecific correlation among morphology, allozymes and mtDNA types in European fire-bellied toads argues that, despite continuous hybridization (interrupted perhaps during Pleistocene glacial maxima), little or no mtDNA introgression between the species has occurred outside the narrow hybrid zones that separate these parapatric species.

Szymura JM; Uzzell T; Spolsky C

2000-07-01

244

Expression pattern of glycoconjugates in the integument of Bufo ictericus (Anuran, Bufonidae): biochemical and histochemical (lectin) profiles.  

Science.gov (United States)

Mucous consists of glycoproteins and proteoglycans produced by specific secretory cells (mucocytes). In anurans the cutaneous mucous is produced by intradermal glands and displays both mechanical and chemical protection functions. Indeed, mucous maintains the integument moist and facilitates gas exchange (cutaneous respiration). In this work, the carbohydrate moiety distribution was investigated in the integument of Bufo ictericus using conventional and lectin histochemistry to describe the pattern of cutaneous glycoconjugate expression, including both secretory and structural proteoglycans. As a preliminary step, the descendent chromatography in Whatmann 1MM paper was undertaken to prepare the histochemical trials involving the lectins. In B. ictericus, the integument exhibits the basic morphological structure found in lower terrestrial vertebrates: the epidermis is a keratinized squamous stratified epithelium supported by spongious and compact layers. The spongy dermis contain secretory portion of both mucous and serous (or poison) glands. The paper chromatography identified galactose, fucose and mannose as characteristic sugar residues. The secretory cells of the mucous gland in the dermis, as well as the interstice between the stratum corneum and the subjacent stratum spinosum in the epidermis exhibit alpha-l-fucose and alpha-galactose residues. The serous glands give no reaction. The alpha-mannose residue was detected in the extracellular matrix of spongious dermis, but not in the dermal glands. The different glycoconjugate location reflects in two glycoconjugates categories: the secretory which participate in the water flow regulation, and the structural which is involved in the dermal maintenance. PMID:17900644

de Brito Gitirana, Lycia; Azevedo, Rodrigo Alves; Pelli, Adriana Alves

2007-09-27

245

Effects of the pineal gland and melatonin on the metabolism of oocytes in vitro and on ovulation in Bufo arenarum.  

Science.gov (United States)

The pineal gland and the hormone melatonin appear to be responsible to some extent for the metabolic behaviour of Bufo arenarum oocytes during the winter. This assumption is supported by the observation that, in isolated mitochondria, both elements stimulate the rate of oxidation of citrate and inhibit that of fumarate, thus raising the oxidizing ratio that relates these parameters (C/F) to values close to or above 1, which is characteristic of these animals in winter. The sensitivity of oocytes to melatonin, in terms of the C/F ratio, varies throughout the year. It is maximal in fall and early winter at a dose of 1.8 micrograms/ml after 30 min treatment, minimal or nonexistent in late winter, and it increases gradually during the spring and summer. The response of oocytes to melatonin is more significant if the animals have been previously injected with a homogenate of homologous hypophysis. A direct metabolic effect of melatonin on oocytes was observed when coelomic oocytes, without follicle cells, responded to hormonal treatment. Both an extract of pineal gland and melatonin inhibit in vitro ovulation, the inhibitory effect of the extract being greater than that of the hormone. PMID:8176358

de Atenor, M S; de Romero, I R; Brauckmann, E; Pisanó, A; Legname, A H

1994-05-01

246

Effects of the pineal gland and melatonin on the metabolism of oocytes in vitro and on ovulation in Bufo arenarum.  

UK PubMed Central (United Kingdom)

The pineal gland and the hormone melatonin appear to be responsible to some extent for the metabolic behaviour of Bufo arenarum oocytes during the winter. This assumption is supported by the observation that, in isolated mitochondria, both elements stimulate the rate of oxidation of citrate and inhibit that of fumarate, thus raising the oxidizing ratio that relates these parameters (C/F) to values close to or above 1, which is characteristic of these animals in winter. The sensitivity of oocytes to melatonin, in terms of the C/F ratio, varies throughout the year. It is maximal in fall and early winter at a dose of 1.8 micrograms/ml after 30 min treatment, minimal or nonexistent in late winter, and it increases gradually during the spring and summer. The response of oocytes to melatonin is more significant if the animals have been previously injected with a homogenate of homologous hypophysis. A direct metabolic effect of melatonin on oocytes was observed when coelomic oocytes, without follicle cells, responded to hormonal treatment. Both an extract of pineal gland and melatonin inhibit in vitro ovulation, the inhibitory effect of the extract being greater than that of the hormone.

de Atenor MS; de Romero IR; Brauckmann E; Pisanó A; Legname AH

1994-05-01

247

Transfer of anti-alcoholic effect of Nux Vomica 200 cH through water from one group of toads to another under alcohol anesthesia  

Directory of Open Access Journals (Sweden)

Full Text Available Background: A common practice is to give homeopathic medication to nursing mothers to treat their children, assuming that the drug will be conveyed by the milk. In the case of conventional treatment, the drug molecules are indeed passed on from the mother to her breastfed infant. However, high dilutions (HD) above 12 cH, i.e., over Avogadro’s number, are traditionally held to lack any molecule from the starting material. If that is the case, then, does medication taken by the mother actually reach the child? To answer to that question, we developed plant models and demonstrated the transfer of HD effects between 2 groups of plants. Aims: To demonstrate the transfer of HD effects in an animal model in a much shorter time. Methods: Two batches of toads were respectively placed in two beakers, one containing Nux vomica 200 cH diluted with water 1:500 (direct treatment), and the other the same amount of distilled water were connected by cotton thread soaked in water and encased in a polyethylene tube (connected group); a third batch of toads (control) were placed in a beaker with 90% ethanol diluted with distilled water 1:500; all the animals were left 30 minutes, and then transferred to 3 independent beakers containing 209 mM ethanol. Every 10 minutes, the motionless toads were removed from the beakers, and placed on supine position, failure to recover the upright position after 60 sec was considered as loss of the righting reflex (RR). The experiment was replicated using large adult toads. Results: The percentage of toads losing the RR increased with the time of exposure to 209 mM ethanol in the 3 groups of toads. Significant difference in the percentage distribution was found between the control and the direct treatment and connected groups on ?2 test (p < 0.001, p < 0.01, respectively), whereby the latter required much longer time to lose the RR, and did not differed between them. In the experiment with large adult toads, the control group lost RR in 78 min, whereas the 2 treated groups did not lose RR even after 240 min. Conclusion: Nux-v 200 cH countered the hypnotic effect of alcohol in young toads, and this effect was transferred through capillary water in the cotton thread, supporting the transfer of the effect of homeopathic medication from mother to child.

Nirmal Chandra Sukul; Indrani Chakraborty; Anirban Sukul; Rathin Chakravarty

2012-01-01

248

Female reciprocal calling in the Iberian midwife toad (Alytes cisternasii) varies with male call rate and dominant frequency: implications for sexual selection  

Science.gov (United States)

Male midwife toads (Alytes cisternasii) responded differently depending on the call frequency and call rate of other males. I tested female Iberian midwife toads with the same set of stimuli used earlier with males. Females responded faster to high call rates, and female vocal activity was greater in response to low-frequency male calls. Thus, in both sexes, the vocal response differs in the same direction according to signal frequency variation, but the magnitude of the response is greater in males than in females. In the light of these results, I discuss the implications for sexual selection of this reciprocal calling.

Bosch, Jaime

2001-08-01

249

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-08-31

250

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

UK PubMed Central (United Kingdom)

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

Guerrero R

2013-03-01

251

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 toads. We found significant differences in the size distribution between areas, being the proportion of juveniles greater at the site next to the swamp where the reproduction of the species was observed. This result may suggest that the site located near to the swamp functions as a source habitat of individuals that migrate to the other site, where recruitment would be very scarce. Sex proportion of adults did not differ from 1:1 in neither the total population nor in each site, suggesting that there was not differential mortality by sex. Some toads changed burrows throughout the study period, but there were not differences in the frequency of change between adults and juveniles.Distribuição de tamanho, razão sexual operacional, e uso de covas do sapo Rhinella fernandezae foram estudados na província de Buenos Aires, Argentina, em dois sítios afastados 300 m. Um deles é uma trilha próxima a um pântano, o outro, um jardim de uma casa rural, mais afastado do pântano. Identificamos as covas dos sapos, e os indivíduos dentro delas foram sexados, medidos e marcados individualmente. As covas foram monitoradas mensalmente, depois da primeira amostragem para avaliar a presença dos sapos. Achamos diferenças na distribuição de tamanhos entres os sítios, sendo a proporção de juvenis maior naquele próximo ao pântano, onde a reprodução da espécie foi observada. O resultado sugere que o sítio próximo ao pântano funciona como um habitat fonte de indivíduos que migram para aquele mais afastado, onde o recrutamento seria escasso. A taxa entre os sexos dos adultos não foi diferente de 1:1 em nenhum dos sítios amostrados, nem na população total, sugerindo que não existe mortalidade diferencial entre machos e fêmeas. Alguns sapos mudaram de cova durante o período do estudo, mas não houve diferenças na freqüência de mudança entre juvenis e adultos.

LC. Sanchez; M. Busch

2008-01-01

252

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

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Distribuição de tamanho, razão sexual operacional, e uso de covas do sapo Rhinella fernandezae foram estudados na província de Buenos Aires, Argentina, em dois sítios afastados 300 m. Um deles é uma trilha próxima a um pântano, o outro, um jardim de uma casa rural, mais afastado do pântano. Identificamos as covas dos sapos, e os indivíduos dentro delas foram sexados, medidos e marcados individualmente. As covas foram monitoradas mensalmente, depois da primeira a (more) mostragem para avaliar a presença dos sapos. Achamos diferenças na distribuição de tamanhos entres os sítios, sendo a proporção de juvenis maior naquele próximo ao pântano, onde a reprodução da espécie foi observada. O resultado sugere que o sítio próximo ao pântano funciona como um habitat fonte de indivíduos que migram para aquele mais afastado, onde o recrutamento seria escasso. A taxa entre os sexos dos adultos não foi diferente de 1:1 em nenhum dos sítios amostrados, nem na população total, sugerindo que não existe mortalidade diferencial entre machos e fêmeas. Alguns sapos mudaram de cova durante o período do estudo, mas não houve diferenças na freqüência de mudança entre juvenis e adultos. Abstract in english 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 (more) the presence of toads. We found significant differences in the size distribution between areas, being the proportion of juveniles greater at the site next to the swamp where the reproduction of the species was observed. This result may suggest that the site located near to the swamp functions as a source habitat of individuals that migrate to the other site, where recruitment would be very scarce. Sex proportion of adults did not differ from 1:1 in neither the total population nor in each site, suggesting that there was not differential mortality by sex. Some toads changed burrows throughout the study period, but there were not differences in the frequency of change between adults and juveniles.

Sanchez, LC.; Busch, M.

2008-02-01

253

Ecological impact assessment in data-poor systems: a case study on metapopulation persistence.  

UK PubMed Central (United Kingdom)

Legislation on the protection of biodiversity (e.g., European Union Habitat and Bird Directives) increasingly requires ecological impact assessment of human activities. However, knowledge and understanding of relevant ecological processes and species responses to different types of impact are often incomplete. In this paper we demonstrate with a case study how impact assessment can be carried out for situations where data are scarce but some expert knowledge is available. The case study involves two amphibian species, the great crested newt (Triturus cristatus) and the natterjack toad (Bufo calamita) in the nature reserve the Meinweg in the Netherlands, for which plans are being developed to reopen an old railway track called the Iron Rhine. We assess the effects of this railway track and its proposed alternatives (scenarios) on the metapopulation extinction time and the occupancy times of the patches for both species using a discrete-time stochastic metapopulation model. We quantify the model parameters using expert knowledge and extrapolated data. Because of our uncertainty about these parameter values, we perform a Monte Carlo uncertainty analysis. This yields an estimate of the probability distribution of the model predictions and insight into the contribution of each distinguished source of uncertainty to this probability distribution. We show that with a simple metapopulation model and an extensive uncertainty analysis it is possible to detect the least harmful scenario. The ranking of the different scenarios is consistent. Thus, uncertainty analysis can enhance the role of ecological impact assessment in decision making by making explicit to what extent incomplete knowledge affects predictions.

Etienne RS; Vos CC; Jansen MJ

2003-12-01

254

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

Directory of Open Access Journals (Sweden)

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; GIUSTI, HumbertoGLASS; GLASS, Mogens Lesner

2010-01-01

255

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

256

Malformations and mortality in the Asian Common Toad induced by exposure to pleurolophocercous cercariae (Trematoda: Cryptogonimidae).  

UK PubMed Central (United Kingdom)

Malformations and increased mortality due to infection by the digenetic trematode, Riberioa ondatrae have been reported for many species of amphibians. Severe malformations have also been reported in the Common Hourglass Tree Frog, Polypedates cruciger induced by pleurolophocercous cercariae in Sri Lanka in addition to the changes in the behaviour, development and survival of the host. We exposed pre-limb bud stage tadpoles (Gosner stages 25-26) of the Asian Common Toad, Duttaphrynus melanostictus to the same pleurolophocercous type cercariae under laboratory conditions. Molecular and morphological identification showed that these cercariae belonged Acanthostomum burminis infecting freshwater snakes as definitive hosts. These cercariae induced malformations (27.8%) and reduced survival to metamorphosis (53.8%). The magnitude of the effects increased with the dose of cercariae. Types of malformations were mainly axial, such as scoliosis and kyphosis. Severe limb malformations such as extra or missing limbs as reported for amphibians exposed to R. ondatrae were not observed in the D. melanostictus. Same authors reported a higher percentage of malformations previously when P. cruciger was exposed to the cercariae A. burminis compared to D. melanostictus. However, tadpoles of D. melanostictus, which are smaller compared to those of P. cruciger, experienced higher mortality than P. cruciger tadpoles. Trematode induced malformations and mortality in amphibians are highly variable and depend on multiple factors such as host species differences such as resistance to infection and tolerance, life-history characteristics such as size at metamorphosis and length of the metamorphosis period, and other factors such as size of the amphibian at the time of trematode exposure.

Jayawardena UA; Tkach VV; Navaratne AN; Amerasinghe PH; Rajakaruna RS

2013-06-01

257

Embryotoxic effects of environmental chemicals: tests with the South African clawed toad (Xenopus laevis)  

Energy Technology Data Exchange (ETDEWEB)

In the course of the investigations reported below, it was shown that p-chloroaniline has a lethal effect on the embryos of Xenopus laevis at a concentration of 100 ppm and is development inhibiting (teratogenic) at concentrations of 1 and 10 ppm, respectively. In the case of aniline, a significant development-inhibiting effect was observed at a concentration as low as 1 ppm. A toxic effect was caused by concentrations between 30 and 40 ppm during embryogenesis and by concentrations above 40 ppm during larval development. A very conspicuous finding was an inhibiting effect of 20 to 40 ppm aniline on pigmentation during embryogenesis and of a concentration as low as 1 ppm on the body size of the young toads. In the case of potassium dichromate, it was possible to barely detect a weak development-inhibiting effect during embryogenesis but no development-retarding effect during larval development. Toxic effects of potassium dichromate occurred during embryogenesis at concentrations of 5 and 7.5 ppm and during the larval development at concentrations above 10 ppm. Sodium dodecylbenzenesulfonic acid at a concentration of 50 ppm was found to have such a strong embryolethal effect that 80% of the eggs showed no cell division at all and the remaining 20% developed to only the bicellular stage. A teratogenic effect of this substance was not observed. Phenol, too, was found to be toxic at a concentration of 50 ppm; in contrast to sodium dodecylbenzenesulfonic acid, however, it did not show any lethal effect on the embryos but it did on the tadpoles, mainly in the first stages of larval development. Lower concentrations of phenol (5 and 10 ppm) had a nonsignificant inhibiting effect on the growth of the larvae. A teratogenic effect of phenol was not detected.

Dumpert, K.

1987-06-01

258

Phylogeography of the fire-bellied toads Bombina: independent Pleistocene histories inferred from mitochondrial genomes.  

Science.gov (United States)

The fire-bellied toads Bombina bombina and Bombina variegata, interbreed in a long, narrow zone maintained by a balance between selection and dispersal. Hybridization takes place between local, genetically differentiated groups. To quantify divergence between these groups and reconstruct their history and demography, we analysed nucleotide variation at the mitochondrial cytochrome b gene (1096 bp) in 364 individuals from 156 sites representing the entire range of both species. Three distinct clades with high sequence divergence (K2P = 8-11%) were distinguished. One clade grouped B. bombina haplotypes; the two other clades grouped B. variegata haplotypes. One B. variegata clade included only Carpathian individuals; the other represented B. variegata from the southwestern parts of its distribution: Southern and Western Europe (Balkano-Western lineage), Apennines, and the Rhodope Mountains. Differentiation between the Carpathian and Balkano-Western lineages, K2P approximately 8%, approached interspecific divergence. Deep divergence among European Bombina lineages suggests their preglacial origin, and implies long and largely independent evolutionary histories of the species. Multiple glacial refugia were identified in the lowlands adjoining the Black Sea, in the Carpathians, in the Balkans, and in the Apennines. The results of the nested clade and demographic analyses suggest drastic reductions of population sizes during the last glacial period, and significant demographic growth related to postglacial colonization. Inferred history, supported by fossil evidence, demonstrates that Bombina ranges underwent repeated contractions and expansions. Geographical concordance between morphology, allozymes, and mtDNA shows that previous episodes of interspecific hybridization have left no detectable mtDNA introgression. Either the admixed populations went extinct, or selection against hybrids hindered mtDNA gene flow in ancient hybrid zones. PMID:17561892

Hofman, Sebastian; Spolsky, Christina; Uzzell, Thomas; Cog?lniceanu, Dan; Babik, Wies?aw; Szymura, Jacek M

2007-06-01

259

Phylogeography of the fire-bellied toads Bombina: independent Pleistocene histories inferred from mitochondrial genomes.  

UK PubMed Central (United Kingdom)

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

Hofman S; Spolsky C; Uzzell T; Cog?lniceanu D; Babik W; Szymura JM

2007-06-01

260

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

CERN Document Server

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

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

2006-01-01

 
 
 
 
261

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

UK PubMed Central (United Kingdom)

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

Ubbels GA; Berendsen W; Kerkvliet S; Narraway J

1992-01-01

262

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

Science.gov (United States)

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

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

2012-04-24

263

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

UK PubMed Central (United Kingdom)

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

Ranatunge RA; Wijesinghe MR; Ratnasooriya WD; Dharmarathne HA; Wijesekera RD

2012-07-01

264

Metabolic evidence that serosal sodium does not recycle through the active transepithelial transport pathway of toad bladder.  

UK PubMed Central (United Kingdom)

The possibility that sodium from the serosal bathing medium "back diffuses" into the active sodium transport pool within the mucosal epithelial cell of the isolated toad bladder was examined by determining the effect on the metabolism of the tissue of removing sodium from the serosal medium. It was expected that if recycling of serosal sodium did occur through the active transepithelial transport pathway of the isolated toad bladder, removal of sodium from the serosal medium would reduce the rate of CO2 production by the tissue and enhance of stoichiometric ratio of sodium ions transported across the bladder per molecula of sodium transport dependent CO2 produced simultaneously by the bladder (JNa/JCO2). The data revealed no significant change in this ratio (17.19 with serosal sodium and 16.13 after replacing serosal sodium with choline). Further, when transepithelial sodium transport was inhibited (a) by adding amiloride to the mucosal medium, or (b) by removing sodium from the mucosal medium, subsequent removal of sodium from the serosal medium, or (c) addition of ouabain failed to depress the basal rate of CO2 production by the bladder [(a)rate of basal, nontransport related, CO2 production (JbCO2) equals 1.54 +/- 0.52 with serosal sodium and 1.54 +/- 0.37 without serosal sodium; (b) Jb CO2 equals 2.18 +/- 0.21 with serosal sodium and 2.09 +/- 0.21 without serosal sodium; (c) 1.14 +/- 0.26 without ouabain and 1.13 +/- 0.25 with ouabain; unite of JbCO2 are nmoles mg d.w.-1 min-1]. The results support the hypothesis that little, if any, recycling of serosal sodium occurs in the total bladder.

Canessa M; Labarca P; Leaf A

1976-12-01

265

Participation of the 39-kDa glycoprotein (gp39) of the vitelline envelope of Bufo arenarum eggs in sperm-egg interaction.  

UK PubMed Central (United Kingdom)

The acquisition of egg fertilizability in Bufo arenarum takes place during the oviductal transit and during this process the extracellular coelomic envelope (CE) of the eggs is converted into the vitelline envelope (VE). It has been stated that one of the necessary events leading to a fertilizable state is the proteolytic cleavage of CE glycoproteins in the oviductal pars recta by oviductin, a serine protease. Consequently, there is a marked increase in the relative quantity of glycoproteins with 39 (gp39) and 42 kDa (gp42) in the VE. In the present study, sperm-VE binding assays using heat-solubilized biotin-conjugated VE glycoproteins revealed that both gp39 and gp42 have sperm binding capacity. According to this result, our study was focused on gp39, a glycoprotein that we have previously reported as a homologue of mammalian ZPC. For this purpose, rabbit polyclonal antibodies against gp39 were generated at our laboratory. The specificity of the antibodies was confirmed with western blot of VE glycoproteins separated on SDS-PAGE. Immunohistochemical and immunoelectron studies showed gp39 distributed throughout the width of the VE. In addition, immunofluorescence assays probed that gp39 bound to the sperm head. Finally, as an approach to elucidate the possible involvement of gp39 in fertilization, inhibition assays showed that pretreatment of eggs with antibodies against gp39 generated a significant decrease in the fertilization rate. Therefore, our findings suggest that gp39, which is modified by oviductal action, participates as a VE glycoprotein ligand for sperm in Bufo arenarum fertilization.

Barrera D; Llanos RJ; Miceli DC

2012-05-01

266

Development of 22 Polymorphic Microsatellite Loci for the Critically Endangered Morato’s Digger Toad, Proceratophrys moratoi  

Directory of Open Access Journals (Sweden)

Full Text Available The Morato’s digger toad (Proceratophrys moratoi) inhabits Brazilian moist savannas and is critically endangered due to its very limited geographic distribution, reduced number of isolated populations, and evidence of population decline and local extinctions. With the objective of providing tools for the genetic study of the species, 22 polymorphic microsatellite loci were isolated and screened using DNA extracted from samples of oral mucosa cells obtained from 113 individuals representing five remnant P. moratoi populations in the Brazilian state of São Paulo. These markers presented 2–18 alleles per locus, polymorphism information content (PIC) of 0.02–0.87, observed heterozygosity of 0.02–0.96 and expected heterozygosity of 0.02–0.87. Three of the loci deviated significantly from Hardy–Weinberg equilibrium in one of the populations, possibly due to the presence of null alleles. Significant linkage disequilibrium was also detected between three pairs of loci. The molecular markers developed in this study were able to discriminate each of the individuals sampled (identity analysis). This means that they will be extremely useful for future genetic studies applied to the conservation of P. moratoi, providing a baseline for estimating the levels of genetic diversity, pedigrees, inbreeding, and population structure, which will be essential for the development of effective genetic management programs.

Maurício Papa Arruda; William Pinheiro Costa; Carla Cristina Silva; Shirlei Maria Recco Pimentel

2012-01-01

267

Preparation and in vitro anti-tumor properties of toad venom extract-loaded solid lipid nanoparticles.  

UK PubMed Central (United Kingdom)

In this study, we prepared solid lipid nanoparticles (TV-SLNs) loaded with toad venom extract and investigated their anti-tumor effects in vitro in HeLa and SKOV-3 cells. TV-SLNs were prepared using a cold homogenization technique, and the formulation was optimized by central composite design and response surface methods. The anti-tumor activities of TV-SLNs were evaluated by analyzing cell division and cell cycle distribution by using the MTT assay and flow cytometry. After incubation with TV-SLNs, the growth of both HeLa and SKOV-3 cells was inhibited significantly. The percentage of HeLa cells in G0/G1 phase decreased, whereas that in the S and G2/M phases increased. Thus, the S and G2/M phases were blocked after the incubation of HeLa cells with TV-SLNs for 24 h. In contrast, the percentage of SKOV-3 cells in G0/G1 phase increased and then decreased in S and G2/M phases, with the G0/G1 phase being blocked after incubation with TV-SLNs for 24 h. Our results demonstrate that TV-SLNs inhibited the fissiparism of HeLa and SKOV-3 cells in a time-and dose-dependent manner. TV-SLNs may be effective as a novel TV vaginal delivery system for the treatment of cervical and ovarian cancers.

Zhang SJ; Zhang YT; Zhao JH; Shen LN; Shi F; Feng NP

2013-08-01

268

Genetic diversity and phylogeography of the Apennine yellow-bellied toad Bombina pachypus, with implications for conservation.  

Science.gov (United States)

Genetic variation was investigated in 17 populations of the Italian endemic Apennine yellow-bellied toad using both mitochondrial (598 bp of the cytochrome b gene) and nuclear (21 allozyme loci) markers. Populations from central Calabria (southern Italy) showed the highest levels of intrapopulation genetic variation, whereas samples located north of this region were nearly lacking in variation. This appears to be a typical pattern of 'southern richness and northern purity', usually attributed to the prolonged population stability within southern refugia coupled with the loss of variation during postglacial northward expansion. However, the overall pattern of genetic variation observed has a strong geographical component, suggesting two Calabrian plains, Catanzaro and Crati-Sibari, as historical barriers to dispersal separating three population groups. These findings cannot be explained by the prolonged stability of southern populations alone, and suggest that the southern richness has been at least in part shaped by allopatric differentiation within the refugial range, followed by intermixing of previously differentiated lineages. From a conservation standpoint, Calabria is the major genetic diversity reservoir for this species, thus deserving particular conservation efforts. Furthermore, although the low intrapopulation genetic variation outside Calabria appears to be of clear historical origin, evidence of a current reduction of gene flow suggests that human disturbance has also played a part, particularly in the anthropogenic impacted Volturno river drainage basin. PMID:17032271

Canestrelli, Daniele; Cimmaruta, Roberta; Costantini, Vera; Nascetti, Giuseppe

2006-10-01

269

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

Directory of Open Access Journals (Sweden)

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; delBarco-Trillo Javier; Vance Carrie K; Milam Callie; Carr Meghan

2012-01-01

270

Cloning and sequence analysis of Bufo arenarum oviductin cDNA and detection of its orthologous gene expression in the mouse female reproductive tract.  

UK PubMed Central (United Kingdom)

The glycoprotein envelope surrounding the Bufo arenarum egg exists in different functional forms. Conversion between types involves proteolysis of specific envelope glycoproteins. When the egg is released from the ovary, the envelope cannot be penetrated by sperm. Conversion to a penetrable state occurs during passage through the pars recta portion of the oviduct, where oviductin, a serine protease with trypsin-like substrate specificity, hydrolyzes two kinds of envelope glycoproteins: gp84 and gp55. The nucleotide sequence of a 3203 bp B. arenarum oviductin cDNA was obtained. Deduced amino acid sequence showed a complete open reading frame encoding 980 amino acids. B. arenarum oviductin is a multi-domain protein with a protease domain at the N-terminal region followed by two CUB domains and toward the C-terminal region another protease domain, which lacked an active histidine site, and one CUB domain. Expression of ovochymase 2, the mammalian orthologous of amphibian oviductin, was assayed in mouse female reproductive tract. Ovochymase 2 mRNA was unnoticeable in the mouse oviduct but expression was remarkable in the uterus. Phylogenetic relationship between oviductin and ovochymase 2 opens the possibility to understand the role of this enzyme in mammalian reproduction.

Barrera D; Valdecantos PA; García EV; Miceli DC

2012-02-01

271

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

UK PubMed Central (United Kingdom)

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.

Brown JR; Miiller T; Kerby JL

2013-09-01

272

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

2013-06-28

273

Miniature end-plate currents and potentials generated by quanta of acetylcholine in glycerol-treated toad sartorius fibres.  

UK PubMed Central (United Kingdom)

1. Part of the end-plate region of glycerol-treated toad sartorius muscle fibres in a hypertonic solution was voltage-clamped using two microelectrodes. The control was adequate for recording miniature end-plate currents (m.e.p.c.s) in the vicinity of the electrodes only, at clamp potentials from - 20 to - 100 mV. At any potential, the peak amplitude of m.e.p.c.s varied widely but their mean amplitude was linearly related to clamp potential. The equilibrium potential, obtained by extrapolation, was more positive than in normal fibres.2. The growth phase of m.e.p.c.s was linear and rapid (< 0.7 msec). The decay phase was exponential. The time constant of decay of m.e.p.c.s was affected by temperature, and increased as the membrane potential was increased. At 20 degrees C, the time constant of decay ranged from 0.8 to 3.8 msec at membrane potentials from - 20 to - 100 mV.3. The mean conductance change caused by a quantum of acetylcholine was 5.5 x 10(-8) mho.4. Voltage responses to rectangular current injections through one electrode were recorded with three other electrodes in the end-plate region of glycerol-treated fibres. Miniature end-plate potentials (m.e.p.p.s) were also recorded with the same four electrodes.5. The decrement of both DC voltage responses and m.e.p.p.s along a fibre was exponential but the m.e.p.p. ;space constant' was significantly shorter than the DC space constant.

Gage PW; McBurney RN

1972-10-01

274

Differentiation of antibody-forming cells in toad spleen. A study using density and sedimentation velocity cell separation.  

UK PubMed Central (United Kingdom)

Antibody-forming cells (AFC), developing in toad spleen after stimulation with polymerized flagellin, were studied with an immune adherence assay. Differentiation was followed by several parameters: thymidine uptake to monitor dividing cells; equilibrium density centrifugation in albumin gradients to monitor cell density; microscopic measurements and sedimentation velocity separation to monitor cell size; stained preparations to follow cell morphology. Almost all AFC observed early in the response were dividing cells; the proportion of dividing AFC dropped to 4% 2 wk after stimulation. The earliest AFC detected (3 days) formed a relatively homogeneous light density population, and were purified 17-fold by equilibrium density centrifugation. As the response developed, additional denser peaks were found, so that late in the response dense AFC predominated. Dividing AFC were confined to the light density region throughout the response. Cell diameter measurements revealed that the earliest AFC were all very large cells. In a manner analogous to the density changes, smaller AFC appeared as the response developed until they finally comprised the majority of the AFC population. Dividing AFC were always relatively large, but encompassed a wide range of sizes. Sedimentation velocity separation was employed in a closer study of the immature AFC; they were purified 140-fold by this procedure. The earliest AFC consisted of several readily separable size populations in the range 9-18 micro diameter. The presence of separate peaks related by factors of two in volume suggested that the largest cells undergo a series of halving divisions before entering a division growth cycle. The results suggest an AFC differentiation sequence from a very large, light density, dividing "blast" cell to a nondividing cell with the size, density, and morphological appearance of a small lymphocyte. Stages of this sequence can be defined and selected out for investigation, using sedimentation velocity and equilibrium density centrifugation as complementary techniques.

Kraft N; Shortman K

1972-02-01

275

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

276

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

Science.gov (United States)

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

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

2013-07-11

277

Anti-inflammatory Drug (Indomethacin) and its Effect on Liver Tumor Induced by DMBA  

Directory of Open Access Journals (Sweden)

Full Text Available Liver tumors were induced in the toads, Bufo regularis, , in 16 out of 50 cases by the administration of 0.2 mg DMBA/toad, 3 times / week for 12 weeks. Light and electron microscopic photographs demonstrate that these hepatocytes of DMBA - treated toads showed criteria of malignancy. In contrast, toads treated with DMBA at the same dose level and 0.005 per cent w/w indomethacin / toad, 3 times / week for 12 weeks showed a lower incidence of liver tumors, 8 out of 50 cases. The biochemical analysis showed that the activity of G6PD, LDH, acid phosphatase and alkaline phosphatase enzymes were decreased in animals treated with DMBA and indomethacin in comparison with toads treated with DMBA alone. It is concluded that indomethacin has an inhibitory effect on hepatocarcinogenesis in toads.

N.E. Abdelmeguid; I.A. Sadek; J. M. Sorour; A.A. Attia

1999-01-01

278

Arenobufagin, a natural bufadienolide from toad venom, induces apoptosis and autophagy in human hepatocellular carcinoma cells through inhibition of PI3K/Akt/mTOR pathway.  

UK PubMed Central (United Kingdom)

Hepatocellular carcinoma (HCC) is a deadly form of cancer without effective chemotherapy so far. Currently, only sorafenib, a multitargeted tyrosine kinase inhibitor, slightly improves survival in HCC patients. In searching for natural anti-HCC components from toad venom, which is frequently used in the treatment of liver cancer in traditional Chinese medicine, we discovered that arenobufagin, a bufadienolide from toad venom, had potent antineoplastic activity against HCC HepG2 cells as well as corresponding multidrug-resistant HepG2/ADM cells. We found that arenobufagin induced mitochondria-mediated apoptosis in HCC cells, with decreasing mitochondrial potential, as well as increasing Bax/Bcl-2 expression ratio, Bax translocation from cytosol to mitochondria. Arenobufagin also induced autophagy in HepG2/ADM cells. Autophagy-specific inhibitors (3-methyladenine, chloroquine and bafilomycin A1) or Beclin1 and Atg 5 small interfering RNAs (siRNAs) enhanced arenobufagin-induced apoptosis, indicating that arenobufagin-mediated autophagy may protect HepG2/ADM cells from undergoing apoptotic cell death. In addition, we observed the inhibition of phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway by arenobufagin. Interestingly, inhibition of mTOR by rapamycin or siRNA duplexes augmented arenobufagin-induced apoptosis and autophagy. Finally, arenobufagin inhibited the growth of HepG2/ADM xenograft tumors, which were associated with poly (ADP-ribose) polymerase cleavage, light chain 3-II activation and mTOR inhibition. In summary, we first demonstrated the antineoplastic effect of arenobufagin on HCC cells both in vitro and in vivo. We elucidated the underlying antineoplastic mechanisms of arenobufagin that involve cross talk between apoptosis and autophagy via inhibition of the PI3K/Akt/mTOR pathway. This study may provide a rationale for future clinical application using arenobufagin as a chemotherapeutic agent for HCC.

Zhang DM; Liu JS; Deng LJ; Chen MF; Yiu A; Cao HH; Tian HY; Fung KP; Kurihara H; Pan JX; Ye WC

2013-06-01

279

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 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 (more) 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 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 d (more) uring 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.

2008-08-01

280

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)  

Directory of Open Access Journals (Sweden)

Full Text Available 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 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.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.

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

2008-01-01

 
 
 
 
281

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

Directory of Open Access Journals (Sweden)

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

Sequeira Fernando; Sodré Davidson; Ferrand Nuno; Bernardi José AR; Sampaio Iracilda; Schneider Horacio; Vallinoto Marcelo

2011-01-01

282

Aislamiento, clonado y expresión de la proteína recombinante para el factor de crecimiento fibroblástico 8 (FgF-8) de Rhinella (= Bufo) arenarum/ Isolation, cloning and expression of the recombinant protein for the fibroblast growth factor 8 (FgF-8) of Rhinella (=Bufo) arenarum  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Los estudios embriológicos han demostrado que el origen de los órganos de vertebrados involucra complejas interacciones celulares de diferentes tejidos. Las investigaciones bioquímicas y moleculares, sugieren que las señales endógenas en la cresta ectodérmica apical (AER) ejercidas por el Factor de Crecimiento Fibroblástico 8 (FGF-8), son claves en los procesos de iniciación del desarrollo de los apéndices pares en vertebrados. El objetivo del presente trabajo fu (more) e obtener una proteína recombinante para el FGF-8 empleando técnicas moleculares, a partir del aislamiento del gen de Rhinella arenarum y analizar la secuencia nucleotídica con herramientas bioinformáticas. Los resultados reflejaron una estrecha relación evolutiva con genes homólogos de otros anfíbios. La obtención de la proteína recombinante, nos brinda la posibilidad de llevar a cabo estudios estructurales y fisiológicos del FGF-8 durante el desarrollo de los miembros en nuestro modelo animal (R. arenarum). un objetivo secundario fue producir anticuerpos policlonales para buscar otras posibles localizaciones y roles de este factor durante el desarrollo. Abstract in english Embryological studies have demonstrated that the origin of organs in vertebrates involves complex cellular interactions in different tissues. Biochemical and molecular evidence suggests that endogenous signal in the apical ectodermical ridge (AER) are exerted by Fibroblastic Growth Factor 8 (FGF-8). This Factor is essencial in the initiation of the limb development processes in vertebrates. The main objective of the present work was to use molecular techniques to obtain a (more) recombinant protein to FGF-8, from the isolation of the Rhinella arenarum toad gene, and to analyze their nucleotidic sequence using bioinformatic tools. It was possible to express the recombinant FGF-8 in a soluble form and also to study the evolutionary relationship with different vertebrate species. The results reflect a near evolutionary relation with other homologous vertebrates genes, especially with the amphibians. The obtencion of the recombinant protein gave us the possibility of carrying out structural and physiologycal studies about the role of FGF-8 during the limb development in our experimental animal model (R. arenarum). A secondary objective was to produce specific polyclonal antibodies which allowed for the search of other possible locations and roles of this factor during vertebrate development.

Paravani, Enrique V.; Acosta, María G.; Diaz Zamboni, Javier E.; Casco, Víctor H.

2009-12-01

283

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

Directory of Open Access Journals (Sweden)

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

Giovanni Scillitani; Angela Maria Moramarco; Roberta Rossi; Maria Mastrodonato

2011-01-01

284

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

UK PubMed Central (United Kingdom)

The beta-adrenergic ligand iodocyanopindolol (ICP) bound specifically to hepatic plasma membrane preparations from the axolotl, Ambystoma mexicanum (Bmax, 40 fmol/mg protein (P) at free concentration above 140 pM; KD, 42 pM); the toad, Xenopus laevis (Bmax, 200 fmol/mg P at 1 nM; KD, 300 pM); and the Australian lungfish, Neoceratodus forsteri (Bmax, 100 fmol/mg P at 5 nM). For the lungfish, the Scatchard plot was curved showing two classes of binding site with KD's of 20 and 500 pM. Neither the alpha 1-adrenergic ligand prazosin nor the alpha 2-adrenergic ligand yohimbine bound specifically to hepatic membrane preparations from any of the three species. Several adrenergic ligands displaced ICP from hepatic membrane preparations of all three species with KD's of Axolotl--propranolol, 50 nM; isoprenaline, 600 nM; adrenaline, 10 microM; phenylephrine, 20 microM; noradrenaline, 40 microM; and phentolamine, greater than 100 microM; X. laevis--propranolol, 30 nM; isoprenaline, 100 microM; adrenaline, 200 microM; noradrenaline, 300 microM; phenylephrine, 1 mM; and phentolamine, greater than 1 mM; N. forsteri,--propranolol, 25 nM; isoprenaline, 1 microM; adrenaline, 20 microM; phenylephrine, 35 microM; noradrenaline, 600 microM; and phentolamine, 400 microM. These findings suggest that alpha-adrenergic receptors are not present in hepatic plasma membrane preparations from these three species and that the hepatic actions of catecholamines are mediated via beta-adrenergic receptors. The order of binding of the beta-adrenergic ligands suggests that the receptors are of the beta 2 type.

Janssens PA; Grigg JA

1988-09-01

285

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

UK PubMed Central (United Kingdom)

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

Bacon JP; Fort CE; Todhunter B; Mathis M; Fort DJ

2013-06-01

286

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

Science.gov (United States)

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

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

2013-03-21

287

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

Science.gov (United States)

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 ?-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 J(1) and J(4) layers, whereas a looser arrangement was observed in the other layers. Jelly-layer glycans were mostly acidic and particularly abundant in the J(1) and J(4) layers. In the J(1), J(2) and J(5) 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 J(5) layer. We believe that, apart from their functions in the fertilization process, acidic and fucosylated glycans could act as a barrier against pathogen penetration. PMID:21744333

Scillitani, Giovanni; Moramarco, Angela Maria; Rossi, Roberta; Mastrodonato, Maria

2011-01-01

288

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

Directory of Open Access Journals (Sweden)

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

Giovanni Scillitani; Angela Maria Moramarco; Roberta Rossi; Maria Mastrodonato

2011-01-01

289

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

UK PubMed Central (United Kingdom)

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 ?-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 J(1) and J(4) layers, whereas a looser arrangement was observed in the other layers. Jelly-layer glycans were mostly acidic and particularly abundant in the J(1) and J(4) layers. In the J(1), J(2) and J(5) 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 J(5) layer. We believe that, apart from their functions in the fertilization process, acidic and fucosylated glycans could act as a barrier against pathogen penetration.

Scillitani G; Moramarco AM; Rossi R; Mastrodonato M

2011-01-01

290

Characterization of the ??-crystallin domains of ??-CAT, a non-lens ??-crystallin and trefoil factor complex, from the skin of the toad Bombina maxima.  

Science.gov (United States)

??-CAT is a naturally existing 72-kDa complex of a non-lens ??-crystallin (?-subunit, CAT-?) and a trefoil factor (?-subunit, CAT-?) that contains a non-covalently linked form of ??(2) and was isolated from the skin secretions of the toad Bombina maxima. The N-terminal region of CAT-? (CAT-?N, residues 1-170) contains two ??-crystallin domains while the C-terminal region (CAT-?C) has sequence homology to the membrane insertion domain of the Clostridium perfringens epsilon toxin. To examine the biochemical characteristics of the ??-crystallin domains of ??-CAT, CAT-?N, CAT-?C and CAT-? were expressed in Escherichia coli. Co-immunoprecipitation of the naturally assembled ??-CAT confirmed that the CAT-? and CAT-? complex always exists. Furthermore, recombinant CAT-? bound recombinant CAT-?N. Ca(2+)-binding motifs were identified in CAT-?N, and recombinant CAT-?N was able to bind the calcium probe terbium. However, the conformation of CAT-?N was not significantly altered upon Ca(2+) binding. ??-CAT possesses strong hemolytic activity toward human erythrocytes, and treatment of erythrocytes with ??-CAT resulted in a rapid Ca(2+) influx, eventually leading to hemolysis. However, in the absence of extracellular Ca(2+), no significant hemolysis was detected, even though the binding and oligomerization of ??-CAT in the erythrocyte membrane was observed. Our data demonstrate the binding of CAT-? (a trefoil factor) to CAT-?N (??-crystallin domains) and provide a basis for the formation of a ??-crystallin and trefoil factor complex in vivo. Furthermore, the ??-crystallin domains of ??-CAT are able to bind Ca(2+), and ??-CAT-induced hemolysis is Ca(2+) dependent. PMID:21784123

Gao, Qian; Xiang, Yang; Zeng, Lin; Ma, Xu Tong; Lee, Wen Hui; Zhang, Yun

2011-07-26

291

Characterization of the ??-crystallin domains of ??-CAT, a non-lens ??-crystallin and trefoil factor complex, from the skin of the toad Bombina maxima.  

UK PubMed Central (United Kingdom)

??-CAT is a naturally existing 72-kDa complex of a non-lens ??-crystallin (?-subunit, CAT-?) and a trefoil factor (?-subunit, CAT-?) that contains a non-covalently linked form of ??(2) and was isolated from the skin secretions of the toad Bombina maxima. The N-terminal region of CAT-? (CAT-?N, residues 1-170) contains two ??-crystallin domains while the C-terminal region (CAT-?C) has sequence homology to the membrane insertion domain of the Clostridium perfringens epsilon toxin. To examine the biochemical characteristics of the ??-crystallin domains of ??-CAT, CAT-?N, CAT-?C and CAT-? were expressed in Escherichia coli. Co-immunoprecipitation of the naturally assembled ??-CAT confirmed that the CAT-? and CAT-? complex always exists. Furthermore, recombinant CAT-? bound recombinant CAT-?N. Ca(2+)-binding motifs were identified in CAT-?N, and recombinant CAT-?N was able to bind the calcium probe terbium. However, the conformation of CAT-?N was not significantly altered upon Ca(2+) binding. ??-CAT possesses strong hemolytic activity toward human erythrocytes, and treatment of erythrocytes with ??-CAT resulted in a rapid Ca(2+) influx, eventually leading to hemolysis. However, in the absence of extracellular Ca(2+), no significant hemolysis was detected, even though the binding and oligomerization of ??-CAT in the erythrocyte membrane was observed. Our data demonstrate the binding of CAT-? (a trefoil factor) to CAT-?N (??-crystallin domains) and provide a basis for the formation of a ??-crystallin and trefoil factor complex in vivo. Furthermore, the ??-crystallin domains of ??-CAT are able to bind Ca(2+), and ??-CAT-induced hemolysis is Ca(2+) dependent.

Gao Q; Xiang Y; Zeng L; Ma XT; Lee WH; Zhang Y

2011-10-01

292

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

UK PubMed Central (United Kingdom)

The Coatzacoalcos Region in Veracruz, Mexico houses one of the most important industrial complexes in Mexico and Latin America. Lead is an ubiquitous environmental pollutant which represents a great risk to human health and ecosystems. Amphibian populations have been recognized as biomonitors of changes in environmental conditions. The purpose of this research is to measure exposure to lead and evaluate hematological and biochemical effects in specimens of giant toads (Rhinella marina) taken from three areas surrounding an industrial complex in the Coatzacoalcos River downstream. Lead levels in toads' blood are between 10.8 and 70.6 ?g/dL and are significantly higher in industrial sites. We have found a significant decrease in the delta-aminolevulinic acid dehydratase (?-ALAD) activity in blood from 35.3 to 78 % for the urban-industrial and industrial sites, respectively. In addition, we have identified a strong inverse relationship between the ?-ALAD activity and the blood lead levels (r = -0.84, p < 0.001). Hemoglobin and mean corpuscular hemoglobin levels, as well as the condition factor, are found to be lower at industrial sites compared with the reference sites. Our results suggest that the R. marina can be considered a good biomonitor of the ?-ALAD activity inhibition and hematological alterations at low lead concentrations.

Ilizaliturri-Hernández CA; González-Mille DJ; Mejía-Saavedra J; Espinosa-Reyes G; Torres-Dosal A; Pérez-Maldonado I

2013-02-01

293

Potential, current, and ionic fluxes across the isolated retinal pigment epithelium and choriod.  

UK PubMed Central (United Kingdom)

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

Lasansky A; De Fisch FW

1966-05-01

294

Physically modeling operative temperatures and evaporation rates in amphibians  

Science.gov (United States)

(1) We designed a physical model that simulates the thermal and evaporative properties of live Western toads (Bufo boreas). (2) In controlled tests, the model tracked the body temperature of live toads with an average error of 0.3??0.03??C (test range=4-30??C). (3) It estimated the evaporative water loss of live toads with an average error of 0.35-0.65 g/h, or about 14% (test range=0.7-9 g/h). (4) Data collected with this physical model should provide an effective way for biologists to better understand habitat selection in toads and other amphibians. ?? 2004 Elsevier Ltd. All rights reserved.

Bartelt, P. E.; Peterson, C. R.

2005-01-01

295

Cattle grazing and conservation of a meadow-dependent amphibian species in the Sierra Nevada.  

UK PubMed Central (United Kingdom)

World-wide population declines have sharpened concern for amphibian conservation on working landscapes. Across the Sierra Nevada's national forest lands, where almost half of native amphibian species are considered at risk, permitted livestock grazing is a notably controversial agricultural activity. Cattle (Bos taurus) grazing is thought to degrade the quality, and thus reduce occupancy, of meadow breeding habitat for amphibian species of concern such as the endemic Yosemite toad (Anaxyrus [?=?Bufo] canorus). However, there is currently little quantitative information correlating cattle grazing intensity, meadow breeding habitat quality, and toad use of meadow habitat. We surveyed biotic and abiotic factors influencing cattle utilization and toad occupancy across 24 Sierra Nevada meadows to establish these correlations and inform conservation planning efforts. We utilized both traditional regression models and Bayesian structural equation modeling to investigate potential drivers of meadow habitat use by cattle and Yosemite toads. Cattle use was negatively related to meadow wetness, while toad occupancy was positively related. In mid and late season (mid July-mid September) grazing periods, cattle selected for higher forage quality diets associated with vegetation in relatively drier meadows, whereas toads were more prevalent in wetter meadows. Because cattle and toads largely occupied divergent zones along the moisture gradient, the potential for indirect or direct negative effects is likely minimized via a partitioning of the meadow habitat. During the early season, when habitat use overlap was highest, overall low grazing levels resulted in no detectable impacts on toad occupancy. Bayesian structural equation analyses supported the hypothesis that meadow hydrology influenced toad meadow occupancy, while cattle grazing intensity did not. These findings suggest cattle production and amphibian conservation can be compatible goals within this working landscape.

Roche LM; Latimer AM; Eastburn DJ; Tate KW

2012-01-01

296

Pesticides are involved with population declines of amphibians in the California Sierra Nevadas.  

UK PubMed Central (United Kingdom)

Several species of frogs and toads are in serious decline in the Sierra Nevada Mountains of California. These species include the threatened red-legged frog ( Rana aurora ), foothill yellow-legged frog ( R. boylii ), mountain yellow-legged frog ( R. muscosa ), Cascades frog ( Rana cascadae ), western toad ( Bufo boreas ) and Yosemite toad ( B. canorus ). For many of these species current distributions are down to 10% of historical ranges. Several factors including introduced predators, habitat loss, and ultraviolet radiation have been suggested as causes of these declines. Another probable cause is air-borne pesticides from the Central Valley of California. The Central Valley, especially the San Joaquin Valley, is a major agricultural region where millions of pounds of active ingredient pesticides are applied each year (http://www.cdpr.ca.gov/dprdatabase.htm). Prevailing westerly winds from the Pacific Coast transport these pesticides into the into the Sierras.

Sparling DW; Fellers G; McConnell L

2001-05-01

297

A miniature microdrive for recording auditory evoked potentials from awake anurans.  

UK PubMed Central (United Kingdom)

Electrical activity recording from the brains of awake animals is a corner stone in the study of the neurophysiological basis of behavior. To meet this need, a microelectrode driver suitable for the animal of interest has to be developed. In the present study a miniature microdrive was developed specifically for the leopard toad, Bufo regularis, however, it can be used for other small animals. The microdrive was designed to meet the following requirements: small size, light weight, simple and easy way of attaching and removing, advancing and withdrawing of microelectrode in the animal brain without rotation, can be reused and made from inexpensive materials. To assess the performance of the developed microdrive, we recorded auditory evoked potentials from different auditory centers in the toad's brain. The potentials were obtained from mesencephalic, diencephalic and telencephalic auditory sensitive areas in response to simple and complex acoustic stimuli. The synthetic acoustical tones introduced to the toad were carrying the dominant frequencies of their mating calls.

Mohammed HS; Radwan NM; Walkowiak W; Elsayed AA

2013-09-01

298

[Influenza in heterothermic animals].  

UK PubMed Central (United Kingdom)

The objective was to study Orthomyxovirus in heterothermic animals. Blood samples from snakes (genus Bothrops and Crotalus) and from toads and frogs (genus Bufo and Rana) were collected to evaluate the red cell receptors and antibodies specific to influenza virus by the hemagglutination and hemagglutination inhibition tests, respectively. Both snakes and toads kept in captivity presented receptors in their red cells and antibodies specific to either influenza virus type A (human and equine origin) or influenza type B. The same was observed with recently captured snakes. Concerning the influenza hemagglutination inhibition antibodies protective levels were observed in the reptiles' serum, against influenza type A and type B. Unlike the toads, 83.3% of the frogs presented mean levels of Ab 40HIU for some influenza strains. It was concluded that heterothermic animals could offer host conditions to the influenza virus and also susceptibility to the infection.

Mancini DA; Mendonça RM; Cianciarullo AM; Kobashi LS; Trindade HG; Fernandes W; Pinto JR

2004-05-01

299

Chemical defense of an Asian snake reflects local availability of toxic prey and hatchling diet.  

UK PubMed Central (United Kingdom)

Species that sequester toxins from prey for their own defense against predators may exhibit population-level variation in their chemical arsenal that reflects the availability of chemically defended prey in their habitat. Rhabdophis tigrinus is an Asian snake that possesses defensive glands in the skin of its neck ('nuchal glands'), which typically contain toxic bufadienolide steroids that the snakes sequester from consumed toads. In this study, we compared the chemistry of the nuchal gland fluid of R. tigrinus from toad-rich and toad-free islands in Japan and determined the effect of diet on the nuchal gland constituents. Our findings demonstrate that captive-hatched juveniles from toad-rich Ishima Island that had not been fed toads possess defensive bufadienolides in their nuchal glands, presumably due to maternal provisioning of these sequestered compounds. Wild-caught juveniles from Ishima possess large quantities of bufadienolides, which could result from a combination of maternal provisioning and sequestration of these defensive compounds from consumed toads. Interestingly, juvenile females from Ishima possess larger quantities of bufadienolides than do juvenile males, whereas a small sample of field-collected snakes suggests that adult males contain larger quantities of bufadienolides than do adult females. Captive-born hatchlings from Kinkasan Island lack bufadienolides in their nuchal glands, reflecting the absence of toads on that island, but they can sequester bufadienolides by feeding on toads (Bufo japonicus) in captivity. The presence of large quantities of bufadienolides in the nuchal glands of R. tigrinus from Ishima may reduce the risk of predation by providing an effective chemical defense, whereas snakes on Kinkasan may experience increased predation due to the lack of defensive compounds in their nuchal glands.

Hutchinson DA; Savitzky AH; Burghardt GM; Nguyen C; Meinwald J; Schroeder FC; Mori A

2013-04-01

300

Biosystematic Study of Anura in the Markazy Province of Central Iran  

Directory of Open Access Journals (Sweden)

Full Text Available Only recently Anuran fauna of Iran has been studied systematically. In order to study the biosystematics of Anuran in the Markazy Province, 122 specimens were collected from six stations during spring and summer 2004-2005. Samples were transferred alive to the zoology laboratory, identified and were preserved. The samples composed of the marsh frog, Rana ridibunda and the green toad, Bufo viridis. The phenetic studies between populations of the two species, 14 characteristics in frog and 17 characteristics in toad were measured. T-test analysis between sexes were significant in 12 characteristics for frogs and only one characteristic for toads (p2 Hotelling for populations and sexes of marsh frog (p<0.001). Length of foot and femur were discriminated distinct sexes based on discrimination analysis with 89% correct grouping for frogs and space between eyelids with 92% correct grouping for toads. Discrimination analysis between populations discriminated groups based on two functions with 78% correct grouping in frogs and 88% correct grouping in toads. Cluster analysis based on centroids grouped populations resulted from geographical and ecological conditions.

Hezaveh Nasim; Ghassemzadeh Fereshteh; Tyler Michael

2007-01-01

 
 
 
 
301

Larval Hannemania sp. infestations of Spea spp. in the Southern High Plains, Texas, USA.  

Science.gov (United States)

We describe a case history of larval Hannemania sp. (Acari: Trombiculidae) infestations in two spadefoot toads (Spea spp. Anura: Pelobatidae) captured from playa wetlands in the Southern High Plains, Texas. Hannemania sp. larvae were superficially attached to the skin, not encysted, and dermal changes were not observed. Gross field examinations revealed a presumed occurrence of Hannemania sp. in Spea spp. at four of 24 wetlands in 2003 and 2004. Although other species of amphibians were present (Ambystoma tigrinum mavortium, Bufo cognatus, Bufo debilis insidior, Pseudacris clarkii, Gastrophryne olivacea, Rana blairi, Scaphiopus couchii), investigators did not observe infestations in these species. Future research should focus on identifying this Hannemania to species level and determining if it influences Spea spp. survival. PMID:17984273

Torrence, Shannon M; Smith, Loren M; McMurry, Scott T

2007-10-01

302

Larval Hannemania sp. infestations of Spea spp. in the Southern High Plains, Texas, USA.  

UK PubMed Central (United Kingdom)

We describe a case history of larval Hannemania sp. (Acari: Trombiculidae) infestations in two spadefoot toads (Spea spp. Anura: Pelobatidae) captured from playa wetlands in the Southern High Plains, Texas. Hannemania sp. larvae were superficially attached to the skin, not encysted, and dermal changes were not observed. Gross field examinations revealed a presumed occurrence of Hannemania sp. in Spea spp. at four of 24 wetlands in 2003 and 2004. Although other species of amphibians were present (Ambystoma tigrinum mavortium, Bufo cognatus, Bufo debilis insidior, Pseudacris clarkii, Gastrophryne olivacea, Rana blairi, Scaphiopus couchii), investigators did not observe infestations in these species. Future research should focus on identifying this Hannemania to species level and determining if it influences Spea spp. survival.

Torrence SM; Smith LM; McMurry ST

2007-10-01

303

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 degenerative changes in the nuclei. These serious side effects should be taken into consideration when using this drug.

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

2000-01-01

304

Cannibalism in a population of the medicinal leech (Hirudo medicinalis L.).  

Science.gov (United States)

Medicinal leeches (Hirudo medicinalis L.) were maintained in large ponds in a commercial leech farm at Biebertal, Germany. The feeding of hungry adult leeches was performed on representative individuals that were placed on cloth soaked with mammalian blood obtained from a local butchery (pig, Sus scrofa). In a second set of experiments, cane toads (Bufo marinus) were used as host organisms. The leeches rapidly attached to the toads, explored the body and sucked blood. After feeding, the fully engorged leeches were placed into the pond or an aquarium. In this artificial habitat, the satiated leeches were attacked by hungry conspecifics, sucked off and killed. This observation demonstrates that H. medicinalis must be classified as a cannibalistic annelid. PMID:16535988

Kutschera, U; Roth, M

305

Cannibalism in a population of the medicinal leech (Hirudo medicinalis L.).  

UK PubMed Central (United Kingdom)

Medicinal leeches (Hirudo medicinalis L.) were maintained in large ponds in a commercial leech farm at Biebertal, Germany. The feeding of hungry adult leeches was performed on representative individuals that were placed on cloth soaked with mammalian blood obtained from a local butchery (pig, Sus scrofa). In a second set of experiments, cane toads (Bufo marinus) were used as host organisms. The leeches rapidly attached to the toads, explored the body and sucked blood. After feeding, the fully engorged leeches were placed into the pond or an aquarium. In this artificial habitat, the satiated leeches were attacked by hungry conspecifics, sucked off and killed. This observation demonstrates that H. medicinalis must be classified as a cannibalistic annelid.

Kutschera U; Roth M

2005-11-01

306

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-07-01

307

An invasive species imposes selection on life-history traits of a native frog  

UK PubMed Central (United Kingdom)

As well as their direct ecological impacts on native taxa, invasive species can impose selection on phenotypic attributes (morphology, physiology, behaviour, etc.) of the native fauna. In anurans, body size at metamorphosis is a critical life-history trait: for most challenges faced by post-metamorphic anurans, larger size at metamorphosis probably enhances survival. However, our studies on Australian frogs (Limnodynastes convexiusculus) show that this pattern can be reversed by the arrival of an invasive species. When metamorph frogs first encounter invasive cane toads (Bufo marinus), they try to eat the toxic invader and, if they are able to do so, are likely to die from poisoning. Because frogs are gape-limited predators, small metamorphs cannot ingest a toad and thus survive long enough to disperse away from the natal pond (and thus from potentially deadly toads). These data show that larger size at metamorphosis can reduce rather than increase anuran survival rates, because larger metamorphs are more easily able to ingest (and thus be poisoned by) metamorph cane toads. Our results suggest that patterns of selection on life-history traits of native taxa (such as size and age at metamorphosis, seasonal timing of breeding and duration of pondside aggregation prior to dispersal) can be modified by the arrival of an invasive species.

GREENLEES MATTHEWJ; PHILLIPS BENJAMINL; SHINE RICHARD

2010-06-01

308

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

UK PubMed Central (United Kingdom)

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

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

1992-04-01

309

Ambient ultraviolet B radiation and prevalence of infection by Batrachochytrium dendrobatidis in two amphibian species.  

UK PubMed Central (United Kingdom)

Chytridiomycosis, the emerging disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd) is responsible for declines and extirpations of amphibian populations worldwide. Environmental covariates modify the host-Bd interaction and thus affect the ongoing spread of the pathogen. One such covariate may be the intensity of ultraviolet B (UV-B) radiation. In a field experiment conducted in Laguna Grande de Peñalara (central Spain), a mountainous region where the presence of Bd has been documented since 1997, we analyzed the potential effect of environmental UV-B (daily maximum 2.5-3.9 W/m(2) ) on the susceptibility of larvae of the common toad (Bufo bufo) to Bd. The proportion of infected individuals increased as tadpoles developed. The prevalence of Bd was significantly lower in tadpoles exposed to environmental UV-B intensities (2.94%) than in tadpoles not exposed to the radiation (9.72%). This finding mirrors that seen for a second amphibian species, the European midwife toad (Alytes obstetricans), for which conditional prevalence (i.e., prevalence of infection conditioned on the probability of a site being infected) across the Iberian Peninsula was inversely correlated with the intensity of UV-B.

Ortiz-Santaliestra ME; Fisher MC; Fernández-Beaskoetxea S; Fernández-Benéitez MJ; Bosch J

2011-10-01

310

Ambient ultraviolet B radiation and prevalence of infection by Batrachochytrium dendrobatidis in two amphibian species.  

Science.gov (United States)

Chytridiomycosis, the emerging disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd) is responsible for declines and extirpations of amphibian populations worldwide. Environmental covariates modify the host-Bd interaction and thus affect the ongoing spread of the pathogen. One such covariate may be the intensity of ultraviolet B (UV-B) radiation. In a field experiment conducted in Laguna Grande de Peñalara (central Spain), a mountainous region where the presence of Bd has been documented since 1997, we analyzed the potential effect of environmental UV-B (daily maximum 2.5-3.9 W/m(2) ) on the susceptibility of larvae of the common toad (Bufo bufo) to Bd. The proportion of infected individuals increased as tadpoles developed. The prevalence of Bd was significantly lower in tadpoles exposed to environmental UV-B intensities (2.94%) than in tadpoles not exposed to the radiation (9.72%). This finding mirrors that seen for a second amphibian species, the European midwife toad (Alytes obstetricans), for which conditional prevalence (i.e., prevalence of infection conditioned on the probability of a site being infected) across the Iberian Peninsula was inversely correlated with the intensity of UV-B. PMID:21676032

Ortiz-Santaliestra, Manuel E; Fisher, Matthew C; Fernández-Beaskoetxea, Saioa; Fernández-Benéitez, María J; Bosch, Jaime

2011-06-15

311

Why are some mitochondria more powerful than others: insights from comparisons of muscle mitochondria from three terrestrial vertebrates.  

UK PubMed Central (United Kingdom)

We studied the molecular composition of muscle mitochondria to evaluate whether the contents of cytochromes or adenine nucleotide translocase (ANT) or phospholipid acyl compositions reflect differences in mitochondrial oxidative capacities. We isolated mitochondria from three vertebrates of similar size and preferred temperature, the rat (Rattus norvegicus), the cane toad (Bufo marinus) and the bearded dragon lizard (Pogona vitticeps). Mitochondrial oxidative capacities were higher in rats and cane toads than in bearded dragon, whether rates were expressed relative to protein, cytochromes or ANT. Inter-specific differences were least pronounced when rates were expressed relative to cytochrome A, a component of cytochrome C oxidase (CCO), or ANT. In mitochondria from rat and cane toad, cytochrome A was more abundant than C followed by B and then C(1), while in bearded dragon mitochondria, the cytochromes were present in roughly equal levels. Analysis of correlations between mitochondrial oxidative capacities and macromolecular components revealed that cytochrome A explained at least half of the intra- and inter-specific variability in substrate oxidation rates. ANT levels were an excellent correlate of state 3 rates while phospholipid contents were correlated with state 4 rates. As the % poly-unsaturation and the % 20:4n-6 in mitochondrial phospholipids were equivalent in toads and rats, and exceeded the levels in lizards, they may contribute to the inter-specific differences in oxidative capacities. We suggest that the numbers of CCO and ANT together with the poly-unsaturation of phospholipids explain the higher oxidative capacities in muscle mitochondria from rats and cane toads.

Guderley H; Turner N; Else PL; Hulbert AJ

2005-10-01

312

Why are some mitochondria more powerful than others: insights from comparisons of muscle mitochondria from three terrestrial vertebrates.  

Science.gov (United States)

We studied the molecular composition of muscle mitochondria to evaluate whether the contents of cytochromes or adenine nucleotide translocase (ANT) or phospholipid acyl compositions reflect differences in mitochondrial oxidative capacities. We isolated mitochondria from three vertebrates of similar size and preferred temperature, the rat (Rattus norvegicus), the cane toad (Bufo marinus) and the bearded dragon lizard (Pogona vitticeps). Mitochondrial oxidative capacities were higher in rats and cane toads than in bearded dragon, whether rates were expressed relative to protein, cytochromes or ANT. Inter-specific differences were least pronounced when rates were expressed relative to cytochrome A, a component of cytochrome C oxidase (CCO), or ANT. In mitochondria from rat and cane toad, cytochrome A was more abundant than C followed by B and then C(1), while in bearded dragon mitochondria, the cytochromes were present in roughly equal levels. Analysis of correlations between mitochondrial oxidative capacities and macromolecular components revealed that cytochrome A explained at least half of the intra- and inter-specific variability in substrate oxidation rates. ANT levels were an excellent correlate of state 3 rates while phospholipid contents were correlated with state 4 rates. As the % poly-unsaturation and the % 20:4n-6 in mitochondrial phospholipids were equivalent in toads and rats, and exceeded the levels in lizards, they may contribute to the inter-specific differences in oxidative capacities. We suggest that the numbers of CCO and ANT together with the poly-unsaturation of phospholipids explain the higher oxidative capacities in muscle mitochondria from rats and cane toads. PMID:16085440

Guderley, Helga; Turner, Nigel; Else, Paul L; Hulbert, A J

2005-10-01

313

Influenza em animais heterotérmicos Influenza in heterothermics  

Directory of Open Access Journals (Sweden)

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

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

2004-01-01

314

Sodium channels in membrane vesicles from cultured toad bladder cells  

International Nuclear Information System (INIS)

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

1988-01-01

315

Sodium channels in membrane vesicles from cultured toad bladder cells  

Energy Technology Data Exchange (ETDEWEB)

Electrical potential-driven {sup 22}Na{sup +} fluxes were measured in membrane vesicles prepared from TBM-18(cl23) cells (a clone of the established cell line TB-M). Fifty to seventy percent of the tracer uptake in vesicles derived from cells that were cultivated on a porous support were blocked by the diuretic amiloride. The amiloride inhibition constant was <0.1 {mu}M, indicating that this flux is mediated by the apical Na{sup +}-specific channels. Vesicles prepared from cells that were not grown on a porous support exhibited much smaller amiloride-sensitive fluxes. Two Ca{sup 2+}-dependent processes that down-regulated the channel conductance and were previously identified in native epithelia were found in the cultured cells as well. Vesicles isolated from cells that were preincubated with 5 {times} 10{sup {minus}7} M aldosterone for 16-20 h exhibited higher amiloride-sensitive conductance than vesicles derived from control, steroid-depleted cells. Thus membrane derived from TBM-18(cl23) cells can be used to characterize the epithelial Na{sup +} channel and its hormonal regulation.

Asher, C.; Moran, A.; Rossier, B.C.; Garty, H. (Weizmann Institute of Science, Rehovot (Israel) Ben Gurion Univ., Beer-Sheva (Israel) Institut de Pharmacologie de l' Universite de Lausanne (Switzerland))

1988-04-01

316

A miniature microdrive for recording auditory evoked potentials from awake anurans.  

Science.gov (United States)

Electrical activity recording from the brains of awake animals is a corner stone in the study of the neurophysiological basis of behavior. To meet this need, a microelectrode driver suitable for the animal of interest has to be developed. In the present study a miniature microdrive was developed specifically for the leopard toad, Bufo regularis, however, it can be used for other small animals. The microdrive was designed to meet the following requirements: small size, light weight, simple and easy way of attaching and removing, advancing and withdrawing of microelectrode in the animal brain without rotation, can be reused and made from inexpensive materials. To assess the performance of the developed microdrive, we recorded auditory evoked potentials from different auditory centers in the toad's brain. The potentials were obtained from mesencephalic, diencephalic and telencephalic auditory sensitive areas in response to simple and complex acoustic stimuli. The synthetic acoustical tones introduced to the toad were carrying the dominant frequencies of their mating calls. PMID:23817637

Mohammed, Haitham S; Radwan, Nasr M; Walkowiak, Wolfgang; Elsayed, Anwar A

2013-07-02

317

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

UK PubMed Central (United Kingdom)

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.

Gomez-Mestre I; Touchon JC; Warkentin KM

2006-10-01

318

Evaluating the effects of anthropogenic stressors on source-sink dynamics in pond-breeding amphibians.  

UK PubMed Central (United Kingdom)

Although interwetland dispersal is thought to play an important role in regional persistence of pond-breeding amphibians, few researchers have modeled amphibian metapopulation or source-sink dynamics. Results of recent modeling studies suggest anthropogenic stressors, such as pollution, can negatively affect density and population viability of amphibians breeding in isolated wetlands. Presumably population declines also result in reduced dispersal to surrounding (often uncontaminated) habitats, potentially affecting dynamics of nearby populations. We used our data on the effects of mercury (Hg) on the American toad (?Bufo americanus) as a case study in modeling the effects of anthropogenic stressors on landscape-scale amphibian dynamics. We created a structured metapopulation model to investigate regional dynamics of American toads and to evaluate the degree to which detrimental effects of Hg contamination on individual populations can disrupt interpopulation dynamics. Dispersal from typical American toad populations supported nearby populations that would otherwise have been extirpated over long time scales. Through support of such sink populations, dispersal between wetland-associated subpopulations substantially increased overall productivity of wetland networks, but this effect declined with increasing interwetland distance and decreasing wetland size. Contamination with Hg substantially reduced productivity of wetland-associated subpopulations and impaired the ability of populations to support nearby sinks within relevant spatial scales. Our results add to the understanding of regional dynamics of pond-breeding amphibians, the wide-reaching negative effects of environmental contaminants, and the potential for restoration or remediation of degraded habitats.

Willson JD; Hopkins WA

2013-06-01

319

A comparative study of hepatic mitochondrial oxygen consumption in four vertebrates by using Clark-type electrode.  

UK PubMed Central (United Kingdom)

The present study was undertaken to establish a comparative account on hepatic mitochondrial oxygen consumption of Clarias gariepinus (fish), Bufo melanostictus (amphibian), Gallus gallus (bird) and Rattus norvegicus (mammal) and to correlate it with their specific metabolic rate (SMR). Mitochondrial oxygen consumption was measured with a Clarke-type electrode with succinate and pyruvate/malate as substrates. ADP was used to start state-III respiration. The results show that rats and chickens have higher oxygen consumption rate than that of fish and toads. Similarly, a species and substrate specific difference was also noticed in P/O (phosphate utilized per oxygen atom) ratio and respiratory control index. In case of rat, a significant negative correlation was noticed between P/O ratio and SMR with succinate as substrate. It is surmised that the observed difference in the mitochondrial respiration and P/O ratio in the above vertebrates is due to the difference in their metabolic activities.

Paital B; Samanta L

2013-06-01

320

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

Directory of Open Access Journals (Sweden)

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

Helene Brettschneider; Philip W. Bateman

2011-01-01

 
 
 
 
321

A comparative study of hepatic mitochondrial oxygen consumption in four vertebrates by using Clark-type electrode.  

Science.gov (United States)

The present study was undertaken to establish a comparative account on hepatic mitochondrial oxygen consumption of Clarias gariepinus (fish), Bufo melanostictus (amphibian), Gallus gallus (bird) and Rattus norvegicus (mammal) and to correlate it with their specific metabolic rate (SMR). Mitochondrial oxygen consumption was measured with a Clarke-type electrode with succinate and pyruvate/malate as substrates. ADP was used to start state-III respiration. The results show that rats and chickens have higher oxygen consumption rate than that of fish and toads. Similarly, a species and substrate specific difference was also noticed in P/O (phosphate utilized per oxygen atom) ratio and respiratory control index. In case of rat, a significant negative correlation was noticed between P/O ratio and SMR with succinate as substrate. It is surmised that the observed difference in the mitochondrial respiration and P/O ratio in the above vertebrates is due to the difference in their metabolic activities. PMID:23739884

Paital, B; Samanta, Luna

2013-06-01

322

Probabilistic secretion of quanta from the release sites of nerve terminals in amphibian muscle modulated by seasonal changes.  

UK PubMed Central (United Kingdom)

The number of quanta secreted from release sites along visualized terminal branches at toad (Bufo marinus) neuromuscular junctions during different seasons was determined. Terminal branches were visualized by prior staining with the fluorescent dye, 3,3'-diethyloxadicarbocyanine iodide (DiOC2(5)). The average number of quanta secreted by release sites and recorded with an extracellular electrode was determined at different positions along terminal branches in winter and summer. There was a decrease in me at different positions along terminal branches in winter compared with me at similar positions in summer during each of 3 years. The observations show that the capacity of release sites to secrete quanta is modulated by seasonal changes.

Bennett MR; Lavidis NA

1991-12-01

323

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

UK PubMed Central (United Kingdom)

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

Grant RA; Halliday T; Balderer WP; Leuenberger F; Newcomer M; Cyr G; Freund FT

2011-06-01

324

[Effect of the heart electric stimulation on repolarization of fish and amphibian ventricular myocardium].  

UK PubMed Central (United Kingdom)

By the method of synchronous multielectrode cartography (24-unipolar leads), distribution of durations and time of end of repolarization were studied on ventricular epicardium of pikes (Esox lucius) and frogs (Rana esculenta) and in ventricular intramural layers of toads (Bufo bufo) at the ectopic heart excitation. The time of arrival of the excitation wave and of the end of repolarization in each lead was determined from the minimum of time derivative of potential at the period of the QRS complex and by minimum of the T wave, respectively. It has been established that at the ventricle electrostimulation, alongside with deceleration and a change of sequence of the myocardium activation, there occurs redistribution of local repolarization durations: in areas of late activation the repolarization being longer than in zones of early activation (p < 0.05). At stimulation, the apicobasal gradient of repolarization is predominantly changed due to electrophysiological processes in the apical areas. In all studied species. at ectopical excitation of the heart ventricle the sequence of its repolarization repeats the depolarization sequence due to delay of activation (in fish) and redistribution of repolarization durations (in amphibians).

Azarov IaÉ; Kibler NA; Va?shnora?te MA; Tsvetkova AS; Kharin SN; Vitiazev VA; Shmakov DN

2013-03-01

325

[Effect of the heart electric stimulation on repolarization of fish and amphibian ventricular myocardium].  

Science.gov (United States)

By the method of synchronous multielectrode cartography (24-unipolar leads), distribution of durations and time of end of repolarization were studied on ventricular epicardium of pikes (Esox lucius) and frogs (Rana esculenta) and in ventricular intramural layers of toads (Bufo bufo) at the ectopic heart excitation. The time of arrival of the excitation wave and of the end of repolarization in each lead was determined from the minimum of time derivative of potential at the period of the QRS complex and by minimum of the T wave, respectively. It has been established that at the ventricle electrostimulation, alongside with deceleration and a change of sequence of the myocardium activation, there occurs redistribution of local repolarization durations: in areas of late activation the repolarization being longer than in zones of early activation (p < 0.05). At stimulation, the apicobasal gradient of repolarization is predominantly changed due to electrophysiological processes in the apical areas. In all studied species. at ectopical excitation of the heart ventricle the sequence of its repolarization repeats the depolarization sequence due to delay of activation (in fish) and redistribution of repolarization durations (in amphibians). PMID:23789398

Azarov, Ia É; Kibler, N A; Va?shnora?te, M A; Tsvetkova, A S; Kharin, S N; Vitiazev, V A; Shmakov, D N

326

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

Science.gov (United States)

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

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

2012-12-03

327

Applying fuzzy logic to comparative distribution modelling: a case study with two sympatric amphibians.  

UK PubMed Central (United Kingdom)

We modelled the distributions of two toads (Bufo bufo and Epidalea calamita) in the Iberian Peninsula using the favourability function, which makes predictions directly comparable for different species and allows fuzzy logic operations to relate different models. The fuzzy intersection between individual models, representing favourability for the presence of both species simultaneously, was compared with another favourability model built on the presences shared by both species. The fuzzy union between individual models, representing favourability for the presence of any of the two species, was compared with another favourability model based on the presences of either or both of them. The fuzzy intersections between favourability for each species and the complementary of favourability for the other (corresponding to the logical operation "A and not B") were compared with models of exclusive presence of one species versus the exclusive presence of the other. The results of modelling combined species data were highly similar to those of fuzzy logic operations between individual models, proving fuzzy logic and the favourability function valuable for comparative distribution modelling. We highlight several advantages of fuzzy logic over other forms of combining distribution models, including the possibility to combine multiple species models for management and conservation planning.

Barbosa AM; Real R

2012-01-01

328

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

329

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

330

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

Directory of Open Access Journals (Sweden)

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; Maneyro, Raúl

1998-01-01

331

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

332

Action of some drugs on the dorsal root potentials of the isolated toad spinal cord  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A series of drugs which potentiate or antagonize transmission at cholinergic synapses have been tested on the slow depolarizing dorsal root potentials evoked by stimulation of adjacent dorsal and ventral roots. Some drugs acted specifically on the dorsal root potential evoked by ventral root stimula...

Kiraly, J. K.; Phillis, J. W.

333

Regulation of luminal membrane water permeability by water flow in toad urinary bladder.  

UK PubMed Central (United Kingdom)

Intramembranous particle aggregates (presumed sites for water flow) which appear in the luminal membrane consequent to ADH treatment are derived from cytoplasmic membrane structures (now termed "aggrephores") which fuse with the luminal membrane. We have previously shown that bladders stimulated in the absence of an osmotic gradient have about twice as many aggregates and about three times as many sites of aggrephore fusion as bladders stimulated with ADH in the presence of a 175 milliosmolal gradient. The present studies show that the frequency of fused aggrephores and luminal membrane aggregates can be modified as a consequence of alterations in transmembrane water flow initiated by changing the transbladder osmotic gradient during hormone stimulation. Bladders treated with ADH for 1 hr without a gradient and then for 1 hr with a gradient had approximately 1/3 as many aggregates and fusion sites as paired bladders treated for 2 hr without a gradient. Conversely, bladders treated with ADH for 1 hr with a gradient and then for 1 hr without a gradient had approximately 2x as many aggregates and fusion sites as bladders treated for 2 hr with a gradient. In other experiments we demonstrate that the time course of hormone washout is greatly accelerated if carried out in the presence of an osmotic gradient. In paired bladders that were first stimulated with ADH for 30 min in the absence of a gradient, aggregates and fusion sites as well as osmotic water permeability determined in fixed bladders, persisted at near maximum levels for 15 min of washout in the absence of a gradient.(ABSTRACT TRUNCATED AT 250 WORDS)

Muller J; Kachadorian WA

1985-01-01

334

LACK OF TERATOGENICITY OF MICROCYSTIN-LR IN THE MOUSE AND TOAD  

Science.gov (United States)

Abstract. Microcystin-LR (MC-LR) is a cyanobacterial toxin generated by the organism, Microcystis aeruginosa. Although the hepatotoxicity of this chemical has been characterized, the potential developmental toxicity in vertebrates has not been well studied. The purpose of this...

335

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 th...

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

336

Effect of Phloretin on Water and Solute Movement in the Toad Bladder  

Digital Repository Infrastructure Vision for European Research (DRIVER)

It is generally believed that urea crosses the cell membrane through aqueous channels, and that its movement across the membrane is accelerated in the direction of net water flow (solvent drag effect). The present report presents evidence for a vasopressin-sensitive pathway for the movement of urea,...

Levine, Sherman; Franki, Nicholas; Hays, Richard M.

337

REGIONAL DYNAMICS OF WETLAND-BREEDING FROGS AND TOADS: TURNOVER AND SYNCHRONY  

Science.gov (United States)

We used data from a statewide frog monitoring network to investigate population turnover and synchrony in eight wetland-breeding species. We found that subpopulations at many sites turn over frequently, with breeding choruses absent or undetectable in most years. Frequencies of d...

338

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

Science.gov (United States)

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

339

Are toad tadpoles unpalatable: Evidence from the behaviour of a predatory dragonfly in South China  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Predators are important determinants of amphibian community structure in aquatic habitats, and larval odonates can be significant predators of amphibian larvae. Despite their toxicity as adults, the palatability of bufonid eggs and tadpoles to vertebrate and invertebrate predators remains widely deb...

Karraker, NE

340

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

Science.gov (United States)

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

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

2006-01-01

 
 
 
 
341

Assessment of the effects of urbanization on trace elements of toe bones.  

UK PubMed Central (United Kingdom)

Amphibians, particularly frogs and toads, are increasingly used as bioindicators of contaminant accumulation in pollution studies. We developed an analytical technique to analyse their elemental contents based on a small amount of toe bone samples. This method is environment-friendly as, unlike traditional methods, it is not necessary to kill animals during sampling. Using this technique, we explored the effects of urbanization on the elemental contents of toe bones. Bufo bufo specimens were collected from an urban and two rural ponds. The ratios of Ca and P at the ponds were: 20.5% Ca and 14.6% P at the urban pond and 30.4% and 29.6% Ca, 22.4% and 21.7% P at the rural ponds, respectively. For the other elements, the following percentage ratios were found: 0.7% B, 0.3% Mg and 0.06% Zn at the urban pond and 1.1% and 0.4% B, 0.4% Mg and 0.05% Zn at the rural ponds, respectively. Canonical discriminant analysis indicated the separation of the urban and the rural ponds based on the elemental concentrations of toe bones. Significant differences were found between the concentrations of Ca, P, Mg, B and Zn at the urban and the rural ponds (p?

Simon E; Puky M; Braun M; Tóthmérész B

2012-09-01

342

Phylogenetic relationships and call structure in four African bufonid species  

Directory of Open Access Journals (Sweden)

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

M.I. Cherry; W.S. Grant

2012-01-01

343

How might you compare mitochondria from different tissues and different species?  

UK PubMed Central (United Kingdom)

Mitochondria were isolated from the liver, kidney and mixed hindlimb skeletal muscle of three vertebrate species; the laboratory rat Rattus norvegicus, the bearded dragon lizard Pogona vitticeps, and the cane toad Bufo marinus. These vertebrate species are approximately the same body mass and have similar body temperatures. The content of cytochromes B, C, C1, and A were measured in these isolated mitochondria by oxidised-reduced difference spectra. Adenine nucleotide translocase (ANT) was measured by titration of mitochondrial respiration with carboxyactractyloside and the protein and phospholipid content of isolated mitochondria were also measured. Fatty acid composition of mitochondrial phospholipids was measured. Mitochondrial respiration was measured at 37 degrees C under states III and IV conditions as well as during oligomycin inhibition. Species differed in the ratios of different mitochondrial cytochromes. Muscle mitochondria differed from kidney and liver mitochondria by having a higher ANT content relative to cytochrome content. Respiration rates were compared relative to a number of denominators and found to be most variable when expressed relative to mitochondrial protein content and least variable when expressed relative to mitochondrial cytochrome A and ANT content. The turnover of cytochromes was calculated and found to vary between 1 and 94 electrons s(-1). The molecular activity of mitochondrial cytochromes was found to be significantly positively correlated with the relative polyunsaturation of mitochondrial membrane lipids.

Hulbert AJ; Turner N; Hinde J; Else P; Guderley H

2006-02-01

344

How might you compare mitochondria from different tissues and different species?  

Science.gov (United States)

Mitochondria were isolated from the liver, kidney and mixed hindlimb skeletal muscle of three vertebrate species; the laboratory rat Rattus norvegicus, the bearded dragon lizard Pogona vitticeps, and the cane toad Bufo marinus. These vertebrate species are approximately the same body mass and have similar body temperatures. The content of cytochromes B, C, C1, and A were measured in these isolated mitochondria by oxidised-reduced difference spectra. Adenine nucleotide translocase (ANT) was measured by titration of mitochondrial respiration with carboxyactractyloside and the protein and phospholipid content of isolated mitochondria were also measured. Fatty acid composition of mitochondrial phospholipids was measured. Mitochondrial respiration was measured at 37 degrees C under states III and IV conditions as well as during oligomycin inhibition. Species differed in the ratios of different mitochondrial cytochromes. Muscle mitochondria differed from kidney and liver mitochondria by having a higher ANT content relative to cytochrome content. Respiration rates were compared relative to a number of denominators and found to be most variable when expressed relative to mitochondrial protein content and least variable when expressed relative to mitochondrial cytochrome A and ANT content. The turnover of cytochromes was calculated and found to vary between 1 and 94 electrons s(-1). The molecular activity of mitochondrial cytochromes was found to be significantly positively correlated with the relative polyunsaturation of mitochondrial membrane lipids. PMID:16408229

Hulbert, A J; Turner, Nigel; Hinde, Jack; Else, Paul; Guderley, Helga

2006-01-12

345

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

UK PubMed Central (United Kingdom)

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

Piprek RP; Pecio A; Kubiak JZ; Szymura JM

2012-08-01

346

The mechanism of action of bufalin in inhibition of lipid droplet accumulation in mouse macrophages.  

UK PubMed Central (United Kingdom)

A cardiotonic glycoside, bufalin, originally isolated from the dried white venom of Chinese toad Bufo gargarizans, was found to inhibit lipid droplet accumulation in mouse macrophages. Bufalin selectively inhibited synthesis of [C]cholesteryl ester (CE), a main component of lipid droplet, from [C]oleic acid and [C]cholesterol with IC values of 8.6 µM and 10 µM, respectively. The postlysosomal metabolism of cholesterol to CE in macrophages was also inhibited by the compound with a similar IC value of 13.2 µM. However, the compound exhibited almost no effect on acyl-CoA?:?cholesterol acyltransferase, a key enzyme in CE synthesis localized in the endoplasmic reticulum (ER). From the fluorescent microscopic observation of cellular lipids, bufalin-treated macrophages increased the accumulation of free cholesterol in lysosomes and caused to enlarge the shape and volume of lysosomes as well as pregnenolone-treated macrophages. These findings suggest that bufalin inhibited the postlysosomal metabolism of cholesterol, leading to a reduction of lipid droplets in mouse macrophages without cytotoxicity.

Kobayashi K; Ohshiro T; Matsuda D; Jiang W; Hong B; Si S; Tomoda H

2013-01-01

347

The mechanism of action of bufalin in inhibition of lipid droplet accumulation in mouse macrophages.  

Science.gov (United States)

A cardiotonic glycoside, bufalin, originally isolated from the dried white venom of Chinese toad Bufo gargarizans, was found to inhibit lipid droplet accumulation in mouse macrophages. Bufalin selectively inhibited synthesis of [C]cholesteryl ester (CE), a main component of lipid droplet, from [C]oleic acid and [C]cholesterol with IC values of 8.6 µM and 10 µM, respectively. The postlysosomal metabolism of cholesterol to CE in macrophages was also inhibited by the compound with a similar IC value of 13.2 µM. However, the compound exhibited almost no effect on acyl-CoA?:?cholesterol acyltransferase, a key enzyme in CE synthesis localized in the endoplasmic reticulum (ER). From the fluorescent microscopic observation of cellular lipids, bufalin-treated macrophages increased the accumulation of free cholesterol in lysosomes and caused to enlarge the shape and volume of lysosomes as well as pregnenolone-treated macrophages. These findings suggest that bufalin inhibited the postlysosomal metabolism of cholesterol, leading to a reduction of lipid droplets in mouse macrophages without cytotoxicity. PMID:23449325

Kobayashi, Keisuke; Ohshiro, Taichi; Matsuda, Daisuke; Jiang, Wei; Hong, Bin; Si, Shuyi; Tomoda, Hiroshi

2013-01-01

348

Toxicity of coelomic fluid of the earthworm Eisenia foetida to vertebrates but not invertebrates: probable role of sphingomyelin.  

UK PubMed Central (United Kingdom)

The coelomic fluid (CF) of the earthworm Eisenia foetida exhibits a wide variety of biological activities. We found that the CF was not toxic to 42 species, belonging to seven invertebrate phyla, almost all in aquatic adults and larvae exposed to CF. Eleven teleostean species tested died in 0.2-1% CF mostly between 10 and 120 min and the effects were dose-dependent. Tadpoles of the toad Bufo japonicus formosus died in 0.4-2% CF between 80 and 225 min depending upon size, with larger tadpoles surviving longer. Before dying, all experimental tadpoles developed curled and shrunken tails. The Okinawa tree lizard, soft-shelled turtle, Japanese quail, mouse and rat all died after i.v. injection of CF (above 20 microl/kg). Thus, CF was not toxic to invertebrates, but toxic to vertebrates. After heating, CF lost its toxicity to fish, tadpoles and mice. Both CF and lysenin incubated with sphingomyelin-liposomes (SM-liposomes) were no longer toxic, suggesting the involvement of SM in the toxicity. Lysenin, which is a constituent of CF and known to bind specifically to sphingomyelin, exhibited toxicity similar to that of CF. Thus, lysenin in CF is probably responsible for the toxic effects of CF by binding to SM in vertebrate tissues. The bodies of invertebrates might contain little or no SM, while those of vertebrates do contain SM. The coelomic fluid of the earthworm Pheretima communissima has no toxicity to mouse.

Kobayashi H; Ohtomi M; Sekizawa Y; Ohta N

2001-03-01

349

Toxicity of coelomic fluid of the earthworm Eisenia foetida to vertebrates but not invertebrates: probable role of sphingomyelin.  

Science.gov (United States)

The coelomic fluid (CF) of the earthworm Eisenia foetida exhibits a wide variety of biological activities. We found that the CF was not toxic to 42 species, belonging to seven invertebrate phyla, almost all in aquatic adults and larvae exposed to CF. Eleven teleostean species tested died in 0.2-1% CF mostly between 10 and 120 min and the effects were dose-dependent. Tadpoles of the toad Bufo japonicus formosus died in 0.4-2% CF between 80 and 225 min depending upon size, with larger tadpoles surviving longer. Before dying, all experimental tadpoles developed curled and shrunken tails. The Okinawa tree lizard, soft-shelled turtle, Japanese quail, mouse and rat all died after i.v. injection of CF (above 20 microl/kg). Thus, CF was not toxic to invertebrates, but toxic to vertebrates. After heating, CF lost its toxicity to fish, tadpoles and mice. Both CF and lysenin incubated with sphingomyelin-liposomes (SM-liposomes) were no longer toxic, suggesting the involvement of SM in the toxicity. Lysenin, which is a constituent of CF and known to bind specifically to sphingomyelin, exhibited toxicity similar to that of CF. Thus, lysenin in CF is probably responsible for the toxic effects of CF by binding to SM in vertebrate tissues. The bodies of invertebrates might contain little or no SM, while those of vertebrates do contain SM. The coelomic fluid of the earthworm Pheretima communissima has no toxicity to mouse. PMID:11255113

Kobayashi, H; Ohtomi, M; Sekizawa, Y; Ohta, N

2001-03-01

350

Aphrodisiacs from plant and animal sources--A review of current scientific literature  

UK PubMed Central (United Kingdom)

The use of aphrodisiacs dates back thousands of years in Chinese, Indian, Egyptian, Roman, and Greek cultures. Although the scientific basis of these substances was not understood, aphrodisiacs were valued for their ability to enhance the sexual experience. Their use allowed for human procreation and the ability to obtain a sexually fulfilling relationship. Aphrodisiacs used historically include ambrein, Bufo toad, Spanish fly, yohimbine, Tribulus terrestris, horny goat weed, muira puama, MACA root, Panax ginseng, nutmeg, saffron, and cacao. Previous studies on these substances have shown potential aphrodisiac properties using animal models and in human clinical trials. Aphrodisiacs were shown to relax corpus cavernosum smooth muscle tissue in animals, improve erection quality in humans and animals, or increase sexual behavior and satisfaction in humans and animals. Although most studies showed positive effects of aphrodisiacs on sexual enhancement, more studies are needed to understand their mechanism of action. The need for clinical trials using larger populations is also evident to prove the effectiveness of aphrodisiacs for human use. This paper will review recent scientific studies conducted on these commonly used aphrodisiacs, and determine whether the results support or refute their use for human sexual enhancement.

Melnyk JP; Marcone MF

2011-05-01

351

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

UK PubMed Central (United Kingdom)

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.

Brinkman SF; Johnston WD

2012-02-01

352

Does maternal exposure to an environmental stressor affect offspring response to predators?  

UK PubMed Central (United Kingdom)

There is growing recognition of the ways in which maternal effects can influence offspring size, physiological performance, and survival. Additionally, environmental contaminants increasingly act as stressors in maternal environments, possibly leading to maternal effects on subsequent offspring. Thus, it is important to determine whether contaminants and other stressors can contribute to maternal effects, particularly under varied ecological conditions that encompass the range under which offspring develop. We used aquatic mesocosms to determine whether maternal effects of mercury (Hg) exposure shape offspring phenotype in the American toad (Bufo americanus) in the presence or absence of larval predators (dragonfly naiads). We found significant maternal effects of Hg exposure and significant effects of predators on several offspring traits, but there was little evidence that maternal effects altered offspring interactions with predators. Offspring from Hg-exposed mothers were 18% smaller than those of reference mothers. Offspring reared with predators were 23% smaller at metamorphosis than those reared without predators. There was also evidence of reduced larval survival when larvae were reared with predators, but this was independent of maternal effects. Additionally, 5 times more larvae had spinal malformations when reared without predators, suggesting selective predation of malformed larvae by predators. Lastly, we found a significant negative correlation between offspring survival and algal density in mesocosms, indicating a role for top-down effects of predators on periphyton communities. Our results demonstrate that maternal exposure to an environmental stressor can induce phenotypic responses in offspring in a direction similar to that produced by direct exposure of offspring to predators.

Todd BD; Bergeron CM; Hepner MJ; Burke JN; Hopkins WA

2011-05-01

353

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Importanza del rospo comune nella dieta invernale di una popolazione di lontra (Lutra lutra) in espansione.
Tramite analisi dei resti fecali, abbiamo evidenziato il ruolo fondamentale degli anfibi nella dieta invernale della lontra

Pablo García-Díaz; César Ayres

354

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.

2010-01-01

355

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

356

Estradiol production by the Bidder's organ of the toad Rhinella arenarum (Amphibia, Anura). Seasonal variations in plasma estradiol.  

UK PubMed Central (United Kingdom)

In bufonids, the Bidder's organ (BO), located in the anterior pole of the testis, is sometimes referred to as a rudimentary ovary because of the presence of previtellogenic follicles. In males of Rhinella arenarum it has been demonstrated that some follicles are vitellogenic and also express several steroidogenic enzymes in follicular cells. The purpose of this study is to describe seasonal variations in plasma estradiol (E(2)) and in aromatase activity of the BO, and to determine the capacity of the BO to synthesize E(2) from cholesterol in males of R. arenarum. E(2) was determined by radioimmunoassay and aromatase activity was measured by transformation of radioactive substrates into products. Results indicate that plasma E(2) reached the highest concentration in April and the lowest one in animals captured in June, showing a progressive increase to the end of the year. Plasma E(2) and total activity of aromatase in the BO were significantly lower during the pre-reproductive season than during the reproductive and post-reproductive seasons. It was also demonstrated that the BO is able to produce E(2) from endogenous substrates throughout the year. No correlation was found between plasma E(2) and total BO weight, while there was a significant correlation between plasma E(2) and total activity of aromatase, and between plasma E(2) and E(2) produced in vitro. Taken together, these results demonstrate seasonal variations in plasma E(2), in bidderian total activity of aromatase and, that the BO of adult males of R. arenarum is able to produce E(2) from endogenous substrates.

Scaia MF; Regueira E; Volonteri MC; Ceballos NR

2013-07-01

357

Interactions between bufadienolides derived from toad venom and verapamil in langendorff-perfused guinea-pig hearts.  

UK PubMed Central (United Kingdom)

Drug toxicity may occur due to dangerous drug combination. We aimed to investigate the influence of verapamil (a P-gp inhibitor)--bufadienolides interaction on cardiotoxicity and bufadienolide uptake by the isolated heart. The study was performed in Langendorff isolated perfused guinea-pig hearts by bufadienolides infusion in the absence and presence of verapamil (250, 500ng/ml). Arrhythmia parameters were evaluated by ECG and the content of bufadienolides in heart were measured by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS). In the present of verapamil, the wide QRS duration and lightly rapid heart rate (HR) were markedly reduced in the early stage of bufadienolide intoxication. However, the ECG changes characterized by prolonged P-R interval, and slow heart rate and low QRS amplitude in the late stage of bufadienolide intoxication were significantly enhanced. Furthermore, the contents of a variety of bufadienolide compounds in the verapamil+bufadienolide group were significantly higher when cardiac arrest occurred. Although verapamil reduced the bufadienolide-induced ventricular arrhythmias, verapamil worsened heart block and lethal bradycardia of bufadienolides partly via increasing the uptake of bufadienolides in heart tissue, which could compromise the protective effects of verapamil against bufadienolide intoxication. These results suggested that the verapamil may produce dangerous interactions with drugs containing bufadienolides.

Ma H; Zhou J; Shang E; Zhang J; Lu W; Zhan Z; Qian D; Duan J; Fan X

2013-02-01

358

Hemoparasites of the genus Trypanosoma (Kinetoplastida: Trypanosomatidae) and hemogregarines in Anurans of the São Paulo and Mato Grosso do Sul States - Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available Wild animals are exposed to numerous pathogens, including hemoparasites. The Trypanosoma and hemogregarinegroup are frequently reported as parasites in anurans (frogs, tree frogs and toads). The identification of these hemoparasites is usually made through stage observation of their morphology in the peripheral blood of the host. There areno studies, however, based on the biological cycle of these hemoparasites. The objective of the present study was toevaluate the presence of hemogregarines and Trypanosoma spp. in anurans captured in the States of São Paulo andMato Grosso do Sul- Brazil and to perform the morphological and morphometric characterization of these hemoparasites. The species of anurans examined were: Dendropsophus nanus, D. minutus, Leptodactylus chaquensis L. podicipinus, L. labyrinthicus, L. fuscus, Bufo granulosus, B. schneideri, Phyllomedusa hypocondrialis, Trachicephalus venulosus, Scinax fuscovarius and Hypsiboas albopunctatus. Of the total of 40 animals studied, four (10%)were positive for hemogregarines and eight (20%) were positive for Trypanosoma spp. Hemogregarine gamontsshowed variable morphology and, in addition to intraerythrocytic forms, extraerythrocytic forms were also observed.Extremely different forms of Trypanosoma were observed, as described in the literature, with the broad and oval forms being the most common.Os animais silvestres estão expostos a inúmeros patógenos,dentre eles estão os hemoparasitas. Podem-se destacar espécies do gênero Trypanosoma e do grupo das hemogregarinas,que ocorrem com freqüência parasitando anuros (rãs, pererecas e sapos). Normalmente, a descrição destes hemoparasitas é feita através da morfologia dos estágios observados nosangue periférico do hospedeiro e as pesquisas sobre o ciclobiológico desses hemoparasitas são escassas. Os objetivos dopresente estudo foram avaliar a presença de hemogregarinas eTrypanosoma spp. em anuros capturados nos Estados de São Paulo e Mato Grosso do Sul e fazer a caracterização morfológica e morfométrica dos seus hemoparasitas. As espécies deanuros examinadas foram: Dendropsophus nanus, D. minutus, Leptodactylus chaquensis, L. podicipinus, L. labyrinthicus, L. fuscus, Bufo granulosus, B. schneideri, Phyllomedusahypocondrialis, Trachicephalus venulosus, Scinax fuscovarius e Hypsiboas albopunctatus. Dos 40 animais estudados, foramencontrados quatro (10%) positivos para hemogregarinas e oito(20%) positivos para Trypanosoma spp. Foram observadosgamontes de hemogregarinas com morfologia variável e, alémdas formas intraeritrocíticas, também foram observados gamontes fora das hemácias. As formas de Trypanosoma encontradas eram muito polimórficas, conforme é descrito na literatura, sendo na sua maioria, larga e oval.

Denise D.M. Leal; Lucia H. O'dwyer; Vitor C. Ribeiro; Reinaldo J. Silva; Vanda L. Ferreira; Rozangela B. Rodrigues

2009-01-01

359

Effects of founder events on the genetic variation of translocated island populations: implications for conservation management of the northern quoll  

UK PubMed Central (United Kingdom)

Translocation is a strategy commonly used to maximize the persistence of threatened species, but it may sometimes lead to undesirable genetic consequences. The northern quoll (Dasyurus hallucatus) is a carnivorous marsupial that is critically endangered in Australia's Northern Territory due to rapid population declines in areas recently colonized by the exotic cane toad Chaunus [Bufo] marinus. In 2003, 64 quolls were translocated to two offshore islands to establish insurance populations and reduce the species' risk of extinction. In this study, we assessed genetic diversity at five microsatellite loci in the translocated populations, two endemic islands and three mainland populations. In the short-term (three generations), the translocated populations showed a slight but non-significant reduction in genetic diversity (A = 4.1-4.2; H e = 0.56-0.59) compared to the mainland source populations (A = 5.0-8.4; H e = 0.56-0.71). In comparison, high genetic erosion was observed in the endemic island populations (A = 1.5-2.9; H e = 0.11-0.34). Genetic bottlenecks were detected on both endemic islands and in one mainland population, indicating recent reductions in population size. Our results are consistent with previous studies describing greater losses of genetic diversity on islands compared to mainland populations. Divergence from ancestral allele frequencies in the translocated populations also suggests effects due to founder events. This study, although short-term, highlights the importance of continued monitoring for detecting changes in genetic diversity over time and makes a significant contribution to our understanding of the effects of founder events on island populations.

Cardoso MariaJ; Eldridge MarkDB; Oakwood Meri; Rankmore Brooke; Sherwin WilliamB; Firestone KarenB

2009-12-01

360

Chytridiomycosis widespread in Anurans of Northeastern United States  

Science.gov (United States)

An emerging disease of amphibians caused by the chytrid fungus Batrachochytrium dendrobatidis has been associated with morbidity, mortality, and extinction of species. Typically, researchers have detected B. dendrobatidis only when examining amphibians for causes of mortalities; few data exist on infection rates where mortalities are lacking. During May?September 2000?2002 we obtained amphibian specimens killed by vehicles and others collected at remote off-road sites throughout Maine, USA, and from federal lands in 5 states in the Northeast. We detected infected specimens, mostly green frogs (Rana clamitans), at 5 of 7 national wildlife refuges, a federal waterfowl production area, and Acadia National Park. Seven of 9 species, including all Ranidae species, were infected throughout Maine; rates ranged from 14.6% in American toads (Bufo americanus) to 25.7% in northern leopard frogs (Rana pipiens). We did not detect any infections in 50 eastern gray tree frogs (Hyla versicolor) or 21 spring peepers (Pseudacris crucifer). Species that hibernate in terrestrial habitats seem to have lower rates of infection than species that hibernate in aquatic habitats. Infections peaked in spring and autumn and were associated with air temperatures optimal for B. dendrobatidis growth. The relatively high infection rates among species without documented die-offs suggest that either losses have occurred undetected, that the fungus is endemic and species have attained a level of resistance to infections becoming lethal, or that climatic conditions of the Northeast have a role in preventing infections from being lethal. Data on prevalence and distribution of this chytrid fungus in the Northeast may be useful in modeling its origins and predicting long-term ecosystem effects involving anurans.

Longcore, J.R.; Longcore, J.E.; Pessier, A.P.; Halteman, W.A.

2007-01-01

 
 
 
 
361

Cross-bridge elasticity in single smooth muscle cells.  

UK PubMed Central (United Kingdom)

In smooth muscle, a cross-bridge mechanism is believed to be responsible for active force generation and fiber shortening. In the present studies, the viscoelastic and kinetic properties of the cross-bridge were probed by eliciting tension transients in response to small, rapid, step length changes (delta L = 0.3-1.0% Lcell in 2 ms). Tension transients were obtained in a single smooth muscle cell isolated from the toad (Bufo marinus) stomach muscularis, which was tied between a force transducer and a displacement device. To record the transients, which were of extremely small magnitude (0.1 microN), a high-frequency (400 Hz), ultrasensitive force transducer (18 mV/microN) was designed and built. The transients obtained during maximal force generation (Fmax = 2.26 microN) were characterized by a linear elastic response (Emax = 1.26 X 10(4) mN/mm2) coincident with the length step, which was followed by a biphasic tension recovery made up of two exponentials (tau fast = 5-20 ms, tau slow = 50-300 ms). During the development of force upon activation, transients were elicited. The relationship between stiffness and force was linear, which suggests that the transients originate within the cross-bridge and reflect the cross-bridge's viscoelastic and kinetic properties. The observed fiber elasticity suggests that the smooth muscle cross-bridge is