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

PubMed

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

2008-02-23

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

A Matter of the Heart: The African Clawed Frog Xenopus as a Model for Studying Vertebrate Cardiogenesis and Congenital Heart Defects

PubMed Central

Hempel, Annemarie; Kühl, Michael

2016-01-01

The African clawed frog, Xenopus, is a valuable non-mammalian model organism to investigate vertebrate heart development and to explore the underlying molecular mechanisms of human congenital heart defects (CHDs). In this review, we outline the similarities between Xenopus and mammalian cardiogenesis, and provide an overview of well-studied cardiac genes in Xenopus, which have been associated with congenital heart conditions. Additionally, we highlight advantages of modeling candidate genes derived from genome wide association studies (GWAS) in Xenopus and discuss commonly used techniques. PMID:29367567

The Genome of the Western Clawed Frog Xenopus tropicalis

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

Hellsten, Uffe; Harland, Richard M.; Gilchrist, Michael J.

2009-10-01

The western clawed frog Xenopus tropicalis is an important model for vertebrate development that combines experimental advantages of the African clawed frog Xenopus laevis with more tractable genetics. Here we present a draft genome sequence assembly of X. tropicalis. This genome encodes over 20,000 protein-coding genes, including orthologs of at least 1,700 human disease genes. Over a million expressed sequence tags validated the annotation. More than one-third of the genome consists of transposable elements, with unusually prevalent DNA transposons. Like other tetrapods, the genome contains gene deserts enriched for conserved non-coding elements. The genome exhibits remarkable shared synteny with humanmore » and chicken over major parts of large chromosomes, broken by lineage-specific chromosome fusions and fissions, mainly in the mammalian lineage.« less

Invited review: Genetics and claw health: Opportunities to enhance claw health by genetic selection

USDA-ARS?s Scientific Manuscript database

Routine recording of claw health status at claw trimming of dairy cattle have been established in several countries, providing valuable data for genetic evaluation. In this review, issues related to genetic evaluation of claw health are examined, data sources, trait definitions and data validation p...

Invited review: Genetics and claw health: Opportunities to enhance claw health by genetic selection.

PubMed

Heringstad, B; Egger-Danner, C; Charfeddine, N; Pryce, J E; Stock, K F; Kofler, J; Sogstad, A M; Holzhauer, M; Fiedler, A; Müller, K; Nielsen, P; Thomas, G; Gengler, N; de Jong, G; Ødegård, C; Malchiodi, F; Miglior, F; Alsaaod, M; Cole, J B

2018-06-01

Routine recording of claw health status at claw trimming of dairy cattle has been established in several countries, providing valuable data for genetic evaluation. In this review, we examine issues related to genetic evaluation of claw health; discuss data sources, trait definitions, and data validation procedures; and present a review of genetic parameters, possible indicator traits, and status of genetic and genomic evaluations for claw disorders. Different sources of data and traits can be used to describe claw health. Severe cases of claw disorders can be identified by veterinary diagnoses. Data from lameness and locomotion scoring, activity information from sensors, and feet and leg conformation traits are used as auxiliary traits. The most reliable and comprehensive information is data from regular hoof trimming. In genetic evaluation, claw disorders are usually defined as binary traits, based on whether or not the claw disorder was present (recorded) at least once during a defined time period. The traits can be specific disorders, composite traits, or overall claw health. Data validation and editing criteria are needed to ensure reliable data at the trimmer, herd, animal, and record levels. Different strategies have been chosen, reflecting differences in herd sizes, data structures, management practices, and recording systems among countries. Heritabilities of the most commonly analyzed claw disorders based on data from routine claw trimming were generally low, with ranges of linear model estimates from 0.01 to 0.14, and threshold model estimates from 0.06 to 0.39. Estimated genetic correlations among claw disorders varied from -0.40 to 0.98. The strongest genetic correlations were found among sole hemorrhage (SH), sole ulcer (SU), and white line disease (WL), and between digital/interdigital dermatitis (DD/ID) and heel horn erosion (HHE). Genetic correlations between DD/ID and HHE on the one hand and SH, SU, or WL on the other hand were, in most cases, low

Effects of environmentally relevant sub-chronic atrazine concentrations on African clawed frog (Xenopus laevis) survival, growth and male gonad development.

PubMed

Rimayi, Cornelius; Odusanya, David; Weiss, Jana M; de Boer, Jacob; Chimuka, Luke; Mbajiorgu, Felix

2018-06-01

Sub-chronic toxicity of environmentally relevant atrazine concentrations on exposed tadpoles and adult male African clawed frogs (Xenopus laevis) was evaluated in a quality controlled laboratory for 90 days. The aim of this study was to determine the effects of atrazine on the survival, growth and gonad development of African clawed frogs. After exposure of tadpoles to atrazine concentrations of 0 (control), 0.01, 200 and 500 μg L -1 in water, mortality rates of 0, 0, 3.3 and 70% respectively were recorded for the 90 day exposure period. Morphometry showed significantly reduced tadpole mass in the 500 μg L -1 atrazine exposed tadpoles (p < 0.05). Light microscopy on testes of adult frogs exposed to the same atrazine concentrations using hematoxylin and eosin (H&E) and Van Gieson staining techniques revealed gonadal atrophy, disruption of germ cell lines, seminiferous tubule structure damage and formation of extensive connective tissue around seminiferous tubules of frogs exposed to 200 μg L -1 and 500 μg L -1 atrazine concentrations. Ultrastructural analysis of the cellular organelles using transmission electron microscopy (TEM) revealed significant amounts of damaged mitochondria in testosterone producing Leydig cells as well as Sertoli cells. Biochemical analysis revealed reduced serum testosterone levels in adult frogs at all exposure levels as well as presence of six atrazine metabolites in frog serum and liver. The results indicate that atrazine concentrations greater than the calculated LC50 of 343.7 μg L -1 cause significant mortality in tadpoles, while concentrations ≥200 μg L -1 adversely affect reproductive health of adult frogs and development of tadpoles sub-chronically exposed to atrazine. Copyright © 2018 Elsevier B.V. All rights reserved.

Identification and characterization of amelogenin genes in monotremes, reptiles, and amphibians

PubMed Central

Toyosawa, Satoru; O’hUigin, Colm; Figueroa, Felipe; Tichy, Herbert; Klein, Jan

1998-01-01

Two features make the tooth an excellent model in the study of evolutionary innovations: the relative simplicity of its structure and the fact that the major tooth-forming genes have been identified in eutherian mammals. To understand the nature of the innovation at the molecular level, it is necessary to identify the homologs of tooth-forming genes in other vertebrates. As a first step toward this goal, homologs of the eutherian amelogenin gene have been cloned and characterized in selected species of monotremes (platypus and echidna), reptiles (caiman), and amphibians (African clawed toad). Comparisons of the homologs reveal that the amelogenin gene evolves quickly in the repeat region, in which numerous insertions and deletions have obliterated any similarity among the genes, and slowly in other regions. The gene organization, the distribution of hydrophobic and hydrophilic segments in the encoded protein, and several other features have been conserved throughout the evolution of the tetrapod amelogenin gene. Clones corresponding to one locus only were found in caiman, whereas the clawed toad possesses at least two amelogenin-encoding loci. PMID:9789040

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

PubMed

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

2017-03-06

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

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

USGS Publications Warehouse

McDiarmid, R.W.; Gorzula, S.

1989-01-01

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

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

USGS Publications Warehouse

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

2014-01-01

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

Curvature facilitates prey fixation in predatory insect claws.

PubMed

Petie, Ronald; Muller, Mees

2007-02-21

Insects show a large variety in prey capture strategies, with a correspondingly large diversity in predatory adaptations. We studied a specific type of predatory claws, these can for example be found in praying mantis species. The claw is closeable over its entire length and the prey is fixed between the femur (upper arm) and the tibia (lower arm) of the insect leg. The morphology of these predatory claws is diverse. Some species have straight claws covered with spines, while other species have smooth, curved claws. We have studied the mechanics of this femur-tibia type of predatory insect claws, by making a physical model, eventually trying to explain why in some insect species the claws are curved instead of straight. The main results are (1) when comparing curved claws to straight claws, curvature leads to a strong reduction of forces driving the prey away from the pivoting point, thereby reducing the need for friction generating structures. (2) In the curved claw model a position exists where the resulting force on the prey is exactly zero. This is because the normal forces on the femur and tibia are opposed, and in line. At this position the prey is perfectly clamped and not driven out of the claw. This feature does not exist in straight claws. (3) In the curved claw, the prey cannot be placed at a position further than a certain maximum distance from the pivoting point. Near this maximum position, the resulting force on the prey reaches high values because moment arms are near zero. (4) Between the zero position and the maximum position the resulting force is directed toward the pivoting point, which stabilizes prey fixation.

Evolutionary variation in the mechanics of fiddler crab claws

PubMed Central

2013-01-01

Background Fiddler crabs, genus Uca, are classic examples of how intense sexual selection can produce exaggerated male traits. Throughout the genus the enlarged “major” cheliped (claw) of the male fiddler crab is used both as a signal for attracting females and as a weapon for combat with other males. However, the morphology of the major claw is highly variable across the approximately 100 species within the genus. Here we address variation, scaling, and correlated evolution in the mechanics of the major claw by analyzing the morphology and mechanical properties of the claws of 21 species of fiddler crabs from the Pacific, Gulf and Atlantic coasts of the Americas. Results We find that the mechanics that produce claw closing forces, the sizes of claws and the mechanical strength of the cuticle of claws are all highly variable across the genus. Most variables scale isometrically with body size across species but claw force production scales allometrically with body size. Using phylogenetically independent contrasts, we find that the force that a claw can potentially produce is positively correlated with the strength of the cuticle on the claw where forces are delivered in a fight. There is also a negative correlation between the force that a claw can potentially produce and the size of the claw corrected for the mass of the claw. Conclusions These relationships suggest that there has been correlated evolution between force production and armoring, and that there is a tradeoff between claw mechanics for signaling and claw mechanics for fighting. PMID:23855770

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

PubMed

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

2016-01-01

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

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

PubMed Central

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

2016-01-01

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

Temperature-independent energy expenditure in early development of the African clawed frog Xenopus laevis.

PubMed

Nagano, Yatsuhisa; Ode, Koji L

2014-08-01

The thermal dissipation of activated eggs and embryos undergoing development from cleavage to the tailbud stage of the African clawed frog Xenopus laevis was measured as a function of incubation time at temperatures ranging from T = 288.2 K to 295.2 K, using a high-precision isothermal calorimeter. A23187-mediated activation of mature eggs induced stable periodic thermal oscillations lasting for 8-34 h. The frequency agreed well with the cell cycle frequency of initial cleavages at the identical temperature. In the developing embryo, energy metabolism switches from embryonic to adult features during gastrulation. The thermal dissipation after gastrulation fit well with a single modified Avrami equation, which has been used for modeling crystal-growth. Both the oscillation frequency of the activated egg and the growth rate of the embryo strongly depend on temperature with the same apparent activation energy of approximately 87 kJ mole(-1). This result suggests that early development proceeds as a single biological time, attributable to a single metabolic rate. A temperature-independent growth curve was derived by scaling the thermogram to the biological time, indicating that the amount of energy expenditure during each developmental stage is constant over the optimal temperature range.

Effect of different flooring systems on claw conformation of dairy cows.

PubMed

Telezhenko, E; Bergsten, C; Magnusson, M; Nilsson, C

2009-06-01

The effect of different flooring surfaces in walking and standing areas on claw conformation, claw horn growth, and wear was studied in 2 experiments during 2 consecutive housing seasons in a research dairy herd of 170 cows. In experiment 1, the flooring systems tested were solid rubber mats, mastic asphalt with and without rubber-matted feed-stalls, and aged concrete slats. In experiment 2, slatted concrete flooring was compared with slatted rubber flooring. The cows were introduced to the respective flooring systems in early lactation and their claws were trimmed before the exposure period. Toe length, toe angle, sole concavity, and claw width, as well as claw growth and wear rates were recorded for lateral and medial claws of the left hind limb. Claw asymmetry calculations were based on these claw measurements and on differences in sole protrusion between lateral and medial soles. Asphalt floors caused shorter toe length and steeper toe angle. They also increased wear on rear claws (5.30 +/- 0.31 and 5.95 +/- 0.33 mm/mo for lateral and medial claw, respectively; LSM +/- SE) and horn growth rate (5.12 +/- 0.36 and 5.83 +/- 0.31 mm/mo of lateral and medial claws, respectively). Rubber mats instead of asphalt in walking areas reduced wear (1.36 +/- 0.19 and 2.02 +/- 0.20 mm/mo for lateral and medial claw, respectively) and claw growth (3.83 +/- 0.23 and 3.94 +/- 0.17 mm/mo for lateral and medial claw, respectively). Rubber-matted feed-stalls together with asphalt walkways decreased claw wear (3.29 +/- 0.31 and 4.10 +/- 0.32 mm/mo for lateral and medial claw, respectively). The concavity of claw soles was reduced on asphalt, especially in the lateral rear claws. Rubber matting in feed-stalls prevented loss of sole concavity compared with asphalt. Claw asymmetry did not differ between flooring systems. While different access to abrasive flooring affected claw conformation, there was no evidence that flooring system influenced the disproportion between lateral and

A simple formula for predicting claw volume of cattle.

PubMed

Scott, T D; Naylor, J M; Greenough, P R

1999-11-01

The object of this study was to develop a simple method for accurately calculating the volume of bovine claws under field conditions. The digits of 30 slaughterhouse beef cattle were examined and the following four linear measurements taken from each pair of claws: (1) the length of the dorsal surface of the claw (Toe); (2) the length of the coronary band (CorBand); (3) the length of the bearing surface (Base); and (4) the height of the claw at the abaxial groove (AbaxGr). Measurements of claw volume using a simple hydrometer were highly repeatable (r(2)= 0.999) and could be calculated from linear measurements using the formula:Claw Volume (cm(3)) = (17.192 x Base) + (7.467 x AbaxGr) + 45.270 x (CorBand) - 798.5This formula was found to be accurate (r(2)= 0.88) when compared to volume data derived from a hydrometer displacement procedure. The front claws occupied 54% of the total volume compared to 46% for the hind claws. Copyright 1999 Harcourt Publishers Ltd.

Claw asymmetry in lobsters: case study in developmental neuroethology.

PubMed

Govind, C K

1992-12-01

An enduring debate in the study of development is the relative contribution of genetic and epigenetic factors in the genesis of an organism, that is, the nature vs. nurture debate. The behavior of the paired claws in the lobster offers promising material for pursuing this debate because of the way they develop. The paired claws and their closer muscles are initially symmetrical; both are slender in appearance and have a mixture of fast and slow fibers in their closer muscles. During a critical period of development, they become determined into a major (crusher) and minor (cutter) claw and during subsequent development acquire their final form and behavior: The crusher becomes a stout, molar-toothed claw capable of closing only slowly because its closer muscle has 100% slow fibers while the cutter becomes a slender, incisor-toothed claw capable of closing rapidly because its closer muscle has 90% fast fibers. Our initial hypothesis was that the more active claw became the crusher and its less active counterpart the cutter. Presumably, nerve activity would influence muscle transformation, which in turn would influence the exoskeleton to which they attach and hence claw morphology. Curtailing nerve activity to the claw prevented crusher development, while reflex activation of a claw promoted its development; both results support the notion that nerve activity directly regulates claw form and function. This is not, however, the case, for when both claws were reflexly exercised neither formed a crusher, signifying rather that bilateral differences in predominantly mechanoreceptive input to the paired claws somehow lateralized the claw ganglion [central nervous system (CNS)] into a crusher and cutter side. The side experiencing the greater activity becomes the crusher side while the contralateral side becomes the cutter and is also inhibited from ever becoming a crusher. This initial lateralization in the CNS is expressed, via as yet unknown pathways, at the periphery in

Sequential Turnovers of Sex Chromosomes in African Clawed Frogs (Xenopus) Suggest Some Genomic Regions Are Good at Sex Determination

PubMed Central

Furman, Benjamin L. S.; Evans, Ben J.

2016-01-01

Sexual differentiation is fundamentally important for reproduction, yet the genetic triggers of this developmental process can vary, even between closely related species. Recent studies have uncovered, for example, variation in the genetic triggers for sexual differentiation within and between species of African clawed frogs (genus Xenopus). Here, we extend these discoveries by demonstrating that yet another sex determination system exists in Xenopus, specifically in the species Xenopus borealis. This system evolved recently in an ancestor of X. borealis that had the same sex determination system as X. laevis, a system which itself is newly evolved. Strikingly, the genomic region carrying the sex determination factor in X. borealis is homologous to that of therian mammals, including humans. Our results offer insights into how the genetic underpinnings of conserved phenotypes evolve, and suggest an important role for cooption of genetic building blocks with conserved developmental roles. PMID:27605520

Claw hand

MedlinePlus

... page: //medlineplus.gov/ency/article/003169.htm Claw hand To use the sharing features on this page, ... Duplication for commercial use must be authorized in writing by ADAM Health Solutions. About MedlinePlus Site Map ...

Claw and limb disorders in 12 Norwegian beef-cow herds

PubMed Central

Fjeldaas, Terje; Nafstad, Ola; Fredriksen, Bente; Ringdal, Grethe; Sogstad, Åse M

2007-01-01

Background The main aim of the study was to assess the prevalence of claw and limb disorders in Norwegian beef-cow herds. Methods Twenty-six herds with ≥15 cow-years were selected by computerized systematic assignment from the three most beef cattle-dense regions of Norway. The study population consisted of 12 herds with 28 heifers and 334 cows. The animals were trimmed and examined once by claw trimmers during the late winter and spring of 2003. The seven claw trimmers had been taught diagnosing and recording of claw lesions. Environment, feeding and management routines, age and breed, culling and carcass characteristics were also recorded. Results Lameness was recorded in 1.1% of the animals, and only in hind claws. Pericarpal swellings were recorded in one animal and peritarsal lesions in none. In total, claw and limb disorders including lameness were recorded in 29.6% of the animals, 4.1% with front and 28.2% with hind limb disorders, respectively. Most lesions were mild. Laminitis-related claw lesions were recorded in 18.0% of the animals and infectious lesions in 16.6%. The average claw length was 84 mm in front claws and 89 mm in hind claw. Both laminitis-related and infectious claw lesions were more prevalent with increasing age. Carcasses from animals with claw and limb disorders were on average 34 kg heavier than carcasses from animals without such disorders (p = 0.02). Our results also indicate association between some management factors and claw lesions. Conclusion The study shows that the prevalence of lameness was low in 12 Norwegian beef-cow herds compared to beef-cattle herds in other countries and also that there were less claw and limb disorders in these herds compared to foreign dairy-cattle herds. The prevalence of lameness and white-line fissures was approximately the same as in Norwegian dairy herds whereas less dermatitis, heel-horn erosions, haemorrhages of the sole and the white line and sole ulcers were recorded. PMID:17892582

Morphology and life history of Petasiger variospinosus (trematoda: echinostomatidae) in the Free State, South Africa.

PubMed

King, P H; Van As, J G

2000-04-01

Specimens of the freshwater snail Bulinus tropicus (Krauss, 1848) collected in the Free State, South Africa shed cercariae with an oral collar bearing 27 spines. Tadpoles of the African clawed toad Xenopus laevis laevis Daudin, 1802 collected from the same waters harbored metacercariae with a similar collar of spines. Adults were obtained after feeding infected tadpoles to laboratory-reared reed cormorants, Phalacrocorax africanus (Gmelin, 1789). The parasite was identified as Petasiger variospinosus (Odhner, 1910), the life cycle was experimentally completed, and stages described by the use of light and scanning electron microscopy.

Morphological and functional diversity in therizinosaur claws and the implications for theropod claw evolution.

PubMed

Lautenschlager, Stephan

2014-06-22

Therizinosaurs are a group of herbivorous theropod dinosaurs from the Cretaceous of North America and Asia, best known for their iconically large and elongate manual claws. However, among Therizinosauria, ungual morphology is highly variable, reflecting a general trend found in derived theropod dinosaurs (Maniraptoriformes). A combined approach of shape analysis to characterize changes in manual ungual morphology across theropods and finite-element analysis to assess the biomechanical properties of different ungual shapes in therizinosaurs reveals a functional diversity related to ungual morphology. While some therizinosaur taxa used their claws in a generalist fashion, other taxa were functionally adapted to use the claws as grasping hooks during foraging. Results further indicate that maniraptoriform dinosaurs deviated from the plesiomorphic theropod ungual morphology resulting in increased functional diversity. This trend parallels modifications of the cranial skeleton in derived theropods in response to dietary adaptation, suggesting that dietary diversification was a major driver for morphological and functional disparity in theropod evolution.

Vortex formation with a snapping shrimp claw.

PubMed

Hess, David; Brücker, Christoph; Hegner, Franziska; Balmert, Alexander; Bleckmann, Horst

2013-01-01

Snapping shrimp use one oversized claw to generate a cavitating high speed water jet for hunting, defence and communication. This work is an experimental investigation about the jet generation. Snapping shrimp (Alpheus-bellulus) were investigated by using an enlarged transparent model reproducing the closure of the snapper claw. Flow inside the model was studied using both High-Speed Particle Image Velocimetry (HS-PIV) and flow visualization. During claw closure a channel-like cavity was formed between the plunger and the socket featuring a nozzle-type contour at the orifice. Closing the mechanism led to the formation of a leading vortex ring with a dimensionless formation number of approximate ΔT*≈4. This indicates that the claw might work at maximum efficiency, i.e. maximum vortex strength was achieved by a minimum of fluid volume ejected. The subsequent vortex cavitation with the formation of an axial reentrant jet is a reasonable explanation for the large penetration depth of the water jet. That snapping shrimp can reach with their claw-induced flow. Within such a cavitation process, an axial reentrant jet is generated in the hollow cylindrical core of the cavitated vortex that pushes the front further downstream and whose length can exceed the initial jet penetration depth by several times.

Milking performance evaluation and factors affecting milking claw vacuum levels with flow simulator.

PubMed

Enokidani, Masafumi; Kawai, Kazuhiro; Shinozuka, Yasunori; Watanabe, Aiko

2017-08-01

Milking performance of milking machines that matches the production capability of dairy cows is important in reducing the risk of mastitis, particularly in high-producing cows. This study used a simulated milking device to examine the milking performance of the milking system of 73 dairy farms and to analyze the factors affecting claw vacuum. Mean claw vacuum and range of fluctuation of claw vacuum (claw vacuum range) were measured at three different flow rates: 5.7, 7.6 and 8.7 kg/min. At the highest flow rate, only 16 farms (21.9%) met both standards of mean claw vacuum ≥35 kPa and claw vacuum range ≤ 7 kPa, showing that milking systems currently have poor milking performance. The factors affecting mean claw vacuum were claw type, milk-meter and vacuum shut-off device; the factor affecting claw vacuum range was claw type. Examination of the milking performance of the milking system using a simulated milking device allows an examination of the performance that can cope with high producing cows, indicating the possibility of reducing the risk of mastitis caused by inappropriate claw vacuum. © 2016 Japanese Society of Animal Science.

Evidence toads may modulate landing preparation without predicting impact time

PubMed Central

Cox, S. M.; Gillis, Gary

2017-01-01

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

Extracellular Ca2+ Is Required for Fertilization in the African Clawed Frog, Xenopus laevis

PubMed Central

Duray, Alexis M.; Tembo, Maiwase; Beleny, David O.; Napolitano, Marc A.; Sauer, Monica L.; Wisner, Bennett W.

2017-01-01

Background The necessity of extracellular Ca2+ for fertilization and early embryonic development in the African clawed frog, Xenopus laevis, is controversial. Ca2+ entry into X. laevis sperm is reportedly required for the acrosome reaction, yet fertilization and embryonic development have been documented to occur in high concentrations of the Ca2+ chelator BAPTA. Here we sought to resolve this controversy. Methodology/principal finding Using the appearance of cleavage furrows as an indicator of embryonic development, we found that X. laevis eggs inseminated in a solution lacking added divalent cations developed normally. By contrast, eggs inseminated in millimolar concentrations of BAPTA or EGTA failed to develop. Transferring embryos to varying solutions after sperm addition, we found that extracellular Ca2+ is specifically required for events occurring within the first 30 minutes after sperm addition, but not after. We found that the fluorescently stained sperm were not able to penetrate the envelope of eggs inseminated in high BAPTA, whereas several had penetrated the vitelline envelope of eggs inseminated without a Ca2+ chelator, or with BAPTA and saturating CaCl2. Together these results indicate that fertilization does not occur in high concentrations of Ca2+ chelators. Finally, we found that the jelly coat includes >5 mM of readily diffusible Ca2+. Conclusions/Significance Taken together, these data are consistent with requirement of extracellular Ca2+ for fertilization. Based on our findings, we hypothesize that the jelly coat surrounding the egg acts as a reserve of readily available Ca2+ ions to foster fertilization in changing extracellular milieu. PMID:28114360

Endocrine effects of 2,2{prime},4,4{prime}-tetrachlorobiphenyl in the African clawed frog (Xenopus laevis)

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

Diana, S.; Hansen, L.; Foley, G.

1995-12-31

Ortho-substituted polychlorinated biphenyls are known to exhibit estrogenic activity and, in some cases, to enhance excretion of tetraiodothyronine (T4), resulting in hypothyroxinemia in mammals. Since thyroxine activity is essential for amphibian metamorphosis, and amphibian sex determination can be altered or reversed by exposure to exogenous estrogens or androgens, the effects of exposure of larvae of the African clawed frog (Xenopus laevis) to 2,2{prime},4,4{prime}-tetrachlorobiphenyl (CB 47) were investigated. Eggs and larvae of X. laevis were exposed to nominal concentrations of CB 47 of 0.05 or 0.25 ppm (1 ppm was found to result in 100% mortality) throughout the period of larvalmore » development, and effects on rates of metamorphosis and body growth and on gonad morphology were determined. Stage of metamorphosis, body length and body weight did not differ between treatment and control groups, following exposure to these sub-lethal concentrations, at any time during larval development. Effects of exposure on gonad morphology will be discussed. The failure of CB 47 to delay or prevent metamorphosis under these conditions may be due to poor responsiveness of hepatic UDP-glucuronyl transferases to induction, or novel systems of thyroxine and/or PCB transport, metabolism and excretion in larval amphibians.« less

Overland movement in African clawed frogs (Xenopus laevis): empirical dispersal data from within their native range.

PubMed

De Villiers, F André; Measey, John

2017-01-01

Dispersal forms are an important component of the ecology of many animals, and reach particular importance for predicting ranges of invasive species. African clawed frogs ( Xenopus laevis ) move overland between water bodies, but all empirical studies are from invasive populations with none from their native southern Africa. Here we report on incidents of overland movement found through a capture-recapture study carried out over a three year period in Overstrand, South Africa. The maximum distance moved was 2.4 km with most of the 91 animals, representing 5% of the population, moving ∼150 m. We found no differences in distances moved by males and females, despite the former being smaller. Fewer males moved overland, but this was no different from the sex bias found in the population. In laboratory performance trials, we found that males outperformed females, in both distance moved and time to exhaustion, when corrected for size. Overland movement occurred throughout the year, but reached peaks in spring and early summer when temporary water bodies were drying. Despite permanent impoundments being located within the study area, we found no evidence for migrations of animals between temporary and permanent water bodies. Our study provides the first dispersal kernel for X. laevis and suggests that it is similar to many non-pipid anurans with respect to dispersal.

Effects of depleted uranium on survival, growth, and metamorphosis in the african clawed frog (Xenopus laevis)

USGS Publications Warehouse

Mitchell, S.E.; Caldwell, C.A.; Gonzales, G.; Gould, W.R.; Arimoto, R.

2005-01-01

Embryos (stage 8-47, Nieuwkoop and Faber) of the African clawed frog (Xenopus laevis) were subjected to water-borne depleted uranium (DU) concentrations that ranged from 4.8 to 77.7 mg/Lusing an acute 96-h frog embryo teratogenesis assay-Xenopus (FETAX). In a chronic 64-d assay, X. laevis (from embryo through metamorphosis; stages 8-66) were subjected to concentrations of DU that ranged from 6.2 to 54.3 mg/L Our results indicate DU is a non teratogenic metal. No effects on mortality, malformations, or growth were observed in the 96-h FETAX with concentrations of DU that ranged from 4.8 to 77.7 mg/L From stage 8 to stage 47, X. laevis tadpoles do not actively feed and the gills are not well developed. Thus, uptake of DU was reduced despite exposure to elevated concentrations. The 64-d assay resulted in no concentration response for either mortality or malformations; however, a delay in metamorphosis was observed in tadpoles subjected to elevated DU concentrations (from 13.1 to 54.3 mg/L) compared to tadpoles in both the well-water control and reference. The delay in metamorphosis was likely due to increasing body burden of DU that ranged from 0.98 to 2.82 mg/kg. Copyright?? Taylor & Francis Inc.

[Claw size of Scottish Highland Cows after pasture and housing periods].

PubMed

Nuss, K; Kolp, E; Braun, U; Weidmann, E; Hässig, M

2014-09-01

The claws of pastured Scottish Highland Cattle are large and this may raise the question if regular claw trimming is necessary. Therefore, the claws of the right thoracic and pelvic limbs were measured in 22 Scottish Highland cows 4 times 8 weeks apart. The cows were kept on various alpine pastures before the first measurement, on a two-hectare low-land pasture before the second measurement, in a welfare-compliant straw-bedded free stall before the third measurement and on alpine pasture before the fourth measurement. Housing conditions significantly affected claw dimensions. The claws were composed of dry, hard horn during pasture periods, and had prominent weight-bearing hoof-wall borders and soles with a natural axial slope. Long dorsal walls and heels and a greater symmetry were common. Claw lesions were absent. In contrast, free-stall housing was associated with shorter toes and steeper toe angles, but white line deterioration, heel horn erosion, wearing of the axial slope and hoof wall edges were common.

The colloidal thyroxine (T4) ring as a novel biomarker of perchlorate exposure in the African clawed frog Xenopus laevis

USGS Publications Warehouse

Hu, F.; Sharma, Bibek; Mukhi, S.; Patino, R.; Carr, J.A.

2006-01-01

The purpose of this study was to determine if changes in colloidal thyroxine (T4) immunoreactivity can be used as a biomarker of perchlorate exposure in amphibian thyroid tissue. Larval African clawed frogs (Xenopus laevis) were exposed to 0, 1, 8, 93, and 1131 ??g perchlorate/l for 38 and 69 days to cover the normal period of larval development and metamorphosis. The results of this study confirmed the presence of an immunoreactive colloidal T4 ring in thyroid follicles of X. laevis and demonstrated that the intensity of this ring is reduced in a concentration-dependent manner by perchlorate exposure. The smallest effective concentration of perchlorate capable of significantly reducing colloidal T4 ring intensity was 8 ??g perchlorate/l. The intensity of the immunoreactive colloidal T4 ring is a more sensitive biomarker of perchlorate exposure than changes in hind limb length, forelimb emergence, tail resorption, thyrocyte hypertrophy, or colloid depletion. We conclude that the colloidal T4 ring can be used as a sensitive biomarker of perchlorate-induced thyroid disruption in amphibians. ?? Copyright 2006 Oxford University Press.

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

Treesearch

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

2011-01-01

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

Claw length recommendations for dairy cow foot trimming

PubMed Central

Archer, S. C.; Newsome, R.; Dibble, H.; Sturrock, C. J.; Chagunda, M. G. G.; Mason, C. S.; Huxley, J. N.

2015-01-01

The aim was to describe variation in length of the dorsal hoof wall in contact with the dermis for cows on a single farm, and hence, derive minimum appropriate claw lengths for routine foot trimming. The hind feet of 68 Holstein-Friesian dairy cows were collected post mortem, and the internal structures were visualised using x-ray µCT. The internal distance from the proximal limit of the wall horn to the distal tip of the dermis was measured from cross-sectional sagittal images. A constant was added to allow for a minimum sole thickness of 5 mm and an average wall thickness of 8 mm. Data were evaluated using descriptive statistics and two-level linear regression models with claw nested within cow. Based on 219 claws, the recommended dorsal wall length from the proximal limit of hoof horn was up to 90 mm for 96 per cent of claws, and the median value was 83 mm. Dorsal wall length increased by 1 mm per year of age, yet 85 per cent of the null model variance remained unexplained. Overtrimming can have severe consequences; the authors propose that the minimum recommended claw length stated in training materials for all Holstein-Friesian cows should be increased to 90 mm. PMID:26220848

Bionic Design for Mars Sampling Scoop Inspired by Himalayan Marmot Claw

PubMed Central

2016-01-01

Cave animals are often adapted to digging and life underground, with claw toes similar in structure and function to a sampling scoop. In this paper, the clawed toes of the Himalayan marmot were selected as a biological prototype for bionic research. Based on geometric parameter optimization of the clawed toes, a bionic sampling scoop for use on Mars was designed. Using a 3D laser scanner, the point cloud data of the second front claw toe was acquired. Parametric equations and contour curves for the claw were then built with cubic polynomial fitting. We obtained 18 characteristic curve equations for the internal and external contours of the claw. A bionic sampling scoop was designed according to the structural parameters of Curiosity's sampling shovel and the contours of the Himalayan marmot's claw. Verifying test results showed that when the penetration angle was 45° and the sampling speed was 0.33 r/min, the bionic sampling scoops' resistance torque was 49.6% less than that of the prototype sampling scoop. When the penetration angle was 60° and the sampling speed was 0.22 r/min, the resistance torque of the bionic sampling scoop was 28.8% lower than that of the prototype sampling scoop. PMID:28127229

Bufo toads and bufotenine: fact and fiction surrounding an alleged psychedelic.

PubMed

Lyttle, T; Goldstein, D; Gartz, J

1996-01-01

This paper investigates the supposedly psychedelic Bufo toad and the allegedly psychedelic drug bufotenine, which is contained in the skin and glands of this toad. The bufo toad has held a place in human mythologies and medicines worldwide since archaic times. Used by ancient peoples for a variety of purposes, its most spectacular effects, according to lore, involve magical and shamanic or occult uses for casting spells and for divination. In the Middle Ages, the Bufo toad was celebrated as a panacea and persecuted as a powerful poison. More recently, in the 1960s the Bufo toad was resurrected as a countercultural icon, with people purportedly licking or smoking the secretions to get high. Bufotenine has been at the center of a scientific debate since its discovery in 1893. This paper examines the extensive literature surrounding the Bufo toad and bufotenine, and untangles many of the myths and the misinformation that continue to vex both science and popular reporting. Finally, to promote further investigation, a comprehensive bibliography is provided that charts the history of the Bufo toad and bufotenine.

Dehydration mediated microRNA response in the African clawed frog Xenopus laevis.

PubMed

Wu, Cheng-Wei; Biggar, Kyle K; Storey, Kenneth B

2013-10-25

Exposure to various environmental stresses induces metabolic rate depression in many animal species, an adaptation that conserves energy until the environment is again conducive to normal life. The African clawed frog, Xenopus laevis, is periodically subjected to arid summers in South Africa, and utilizes entry into the hypometabolic state of estivation as a mechanism of long term survival. During estivation, frogs must typically deal with substantial dehydration as their ponds dry out and X. laevis can endure >30% loss of its body water. We hypothesize that microRNAs play a vital role in establishing a reversible hypometabolic state and responding to dehydration stress that is associated with amphibian estivation. The present study analyzes the effects of whole body dehydration on microRNA expression in three tissues of X. laevis. Compared to controls, levels of miR-1, miR-125b, and miR-16-1 decreased to 37±6, 64±8, and 80±4% of control levels during dehydration in liver. By contrast, miR-210, miR-34a and miR-21 were significantly elevated by 3.05±0.45, 2.11±0.08, and 1.36±0.05-fold, respectively, in the liver. In kidney tissue, miR-29b, miR-21, and miR-203 were elevated by 1.40±0.09, 1.31±0.05, and 2.17±0.31-fold, respectively, in response to dehydration whereas miR-203 and miR-34a were elevated in ventral skin by 1.35±0.05 and 1.74±0.12-fold, respectively. Bioinformatic analysis of the differentially expressed microRNAs suggests that these are mainly involved in two processes: (1) expression of solute carrier proteins, and (2) regulation of mitogen-activated protein kinase signaling. This study is the first report that shows a tissue specific mode of microRNA expression during amphibian dehydration, providing evidence for microRNAs as crucial regulators of metabolic depression. © 2013 Elsevier B.V. All rights reserved.

Synthetic rainfall vibrations evoke toad emergence.

PubMed

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

2016-12-19

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

Identification and characterization of integrin-binding sialoprotein (IBSP) genes in reptile and amphibian.

PubMed

Shintani, Seikou; Kamakura, Naofumi; Kobata, Mitsuhiko; Toyosawa, Satoru; Onishi, Tomoyuki; Sato, Akie; Kawasaki, Kazuhiko; Weiss, Kenneth M; Ooshima, Takashi

2008-11-15

Integrin-binding sialoprotein (IBSP) is a member of the small integrin-binding ligand N-linked glycoprotein (SIBLING) family; and the whole SIBLING family is further included in a larger secretory calcium-binding phosphoprotein (SCPP) family. SIBLING proteins are known to construct a part of the non-collagenous extracellular matrices of calcified tissues, and considered to have arisen by duplication and subsequent divergent evolution of a single ancient gene. To understand the alterations of SIBLING molecules associated with the evolution of calcified tissues in vertebrates, we initiated a search for lower vertebrate orthologs of SIBLING genes. In the present study, an IBSP ortholog from a reptile (caiman) and two distinct orthologs from an amphibian (African clawed toad) were identified and characterized. As expected, the toad IBSP genes were transcribed only in calcified tissue (jaw and tibia), as also seen in mammals. The caiman, toad, avian, and mammalian IBSPs share several unique features specific for IBSP and apparently have similar properties. Furthermore, analysis of the sequences suggested that the IBSP molecule might have gradually intensified its functions related to calcification during its evolutionary process through tetrapods.

Comparative toxicity of ammonium and nitrate compounds to Pacific treefrog and African clawed frog tadpoles

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

Schuytema, G.S.; Nebeker, A.V.

1999-10-01

The effects of ammonium nitrate, ammonium chloride, ammonium sulfate, and sodium nitrate on survival and growth of Pacific treefrog (Pseudacris regilla [Baird and Girard]) and African clawed frog (Xenopus laevis [Daudin]) tadpoles were determined in static-renewal tests. The 10-d ammonium nitrate and ammonium sulfate LC50s for P. regilla were 55.2 and 89.7 mg/L NH{sub 4}-N, respectively. The 10-d LC50s for X. laevis for the three ammonium compounds ranged from 45 to 64 mg/L NH{sub 4}-N. The 10-d sodium nitrate LC50s were 266.2 mg/L NO{sub 3}-N for P. regilla and 1,236.2 mg/L NO{sub 3}-N for X. laevis. The lowest observed adversemore » effect level (LOAEL) of ammonium compound based on reduced length or weight was 24.6 mg/L NH{sub 4}-N for P. regilla and 99.5 mg/L NH{sub 4}-N for X. laevis. The lowest sodium nitrate LOAELs based on reduced length or weight were {lt}30.1 mg/L NO{sub 3}-N for P. regilla and 126.3 mg/L NO{sub 3}-N for X. laevis. Calculated un-ionized NH{sub 3} comprised 0.3 to 1.0% of measured NH{sub 4}-N concentrations. Potential harm to amphibians could occur if sensitive life stages were impacted by NH{sub 4}-N and NO{sub 3}-N in agricultural runoff or drainage for a sufficiently long period.« less

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

PubMed

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

2015-09-01

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

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

PubMed

Portik, Daniel M; Papenfuss, Theodore J

2015-08-06

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

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

USGS Publications Warehouse

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

2005-01-01

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

ICAR claw health atlas

USDA-ARS?s Scientific Manuscript database

Awareness of the importance of a properly functioning locomotor system to bovine health and welfare has increased around the world. Several countries have recently introduced electronic systems to routinely record foot and claw disorders in dairy cattle and many more countries are developing plans o...

Shock characterization of toad pins

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

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

1996-05-01

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

Shock characterization of TOAD pins

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

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

1995-08-01

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

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

PubMed

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

2002-01-14

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

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

PubMed Central

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

2012-01-01

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

Unique fatality due to claw injuries in a tiger attack: a case report.

PubMed

Pathak, Hrishikesh; Dixit, Pradeep; Dhawane, Shailendra; Meshram, Satin; Shrigiriwar, Manish; Dingre, Niraj

2014-11-01

This paper describes a unique case of a fatal tiger attack in the wild. In the present case, a tiger fatally mauled a 34-year-old female with its claws, instead of the usual mechanism of killing by the bite injury to the neck. The autopsy revealed multiple fatal and non-fatal injuries caused by the tiger claws. The characteristic injuries due to the tooth impacts were absent as the teeth of the offending tiger were either fallen or non-functional. To the best of our knowledge, probably this rare case would be the first reported human fatality due to the tiger claw injuries in the world. The purpose of the present article is to highlight the fatal injuries due to the tiger claws, as the claw-induced fatal injuries in a tiger attack are not reported in the medico-legal literature. Moreover, this report would be an illustrative one for differentiation between the fatal injuries due to the claws and tooth impacts in a tiger attack. Furthermore, the present report establishes the importance of the tiger claws as a source of fatal injuries in a tiger attack. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Effect of saponin treatment on the sarcoplasmic reticulum of rat, cane toad and crustacean (yabby) skeletal muscle.

PubMed Central

Launikonis, B S; Stephenson, D G

1997-01-01

1. Mechanically skinned fibres from skeletal muscles of the rat, toad and yabby were used to investigate the effect of saponin treatment on sarcoplasmic reticulum (SR) Ca2+ loading properties. The SR was loaded submaximally under control conditions before and after treatment with saponin and SR Ca2+ was released with caffeine. 2. Treatment with 10 micrograms ml-1 saponin greatly reduced the SR Ca2+ loading ability of skinned fibres from the extensor digitorum longus muscle of the rat with a rate constant of 0.24 min-1. Saponin concentrations up to 150 micrograms ml-1 and increased exposure time up to 30 min did not further reduce the SR Ca2+ loading ability of the SR, which indicates that the inhibitory action of 10-150 micrograms ml-1 saponin is not dose dependent. The effect of saponin was also not dependent on the state of polarization of the transverse-tubular system. 3. Treatment with saponin at concentrations up to 100 micrograms ml-1 for 30 min did not affect the Ca2+ loading ability of SR in skinned skeletal muscle fibres from the twitch portion of the toad iliofibularis muscle but SR Ca2+ loading ability decreased markedly with a time constant of 0.22 min-1 in the presence of 150 micrograms ml-1 saponin. 4. The saponin dependent increase in permeability could be reversed in both rat and toad fibres by short treatment with 6 microM Ruthenium Red, a potent SR Ca2+ channel blocker, suggesting that saponin does affect the SR Ca2+ channel properties in mammalian and anuran skeletal muscle. 5. Treatment of skinned fibres of long sarcomere length (> 6 microns) from the claw muscle of the yabby (a freshwater decapod crustacean) with 10 micrograms ml-1 saponin for 30 min abolished the ability of the SR to load Ca2+, indicating that saponin affects differently the SR from skeletal muscles of mammals, anurans and crustaceans. 6. It is concluded that at relatively low concentrations, saponin causes inhibition of the skeletal SR Ca2+ loading ability in a species

Effect of saponin treatment on the sarcoplasmic reticulum of rat, cane toad and crustacean (yabby) skeletal muscle.

PubMed

Launikonis, B S; Stephenson, D G

1997-10-15

1. Mechanically skinned fibres from skeletal muscles of the rat, toad and yabby were used to investigate the effect of saponin treatment on sarcoplasmic reticulum (SR) Ca2+ loading properties. The SR was loaded submaximally under control conditions before and after treatment with saponin and SR Ca2+ was released with caffeine. 2. Treatment with 10 micrograms ml-1 saponin greatly reduced the SR Ca2+ loading ability of skinned fibres from the extensor digitorum longus muscle of the rat with a rate constant of 0.24 min-1. Saponin concentrations up to 150 micrograms ml-1 and increased exposure time up to 30 min did not further reduce the SR Ca2+ loading ability of the SR, which indicates that the inhibitory action of 10-150 micrograms ml-1 saponin is not dose dependent. The effect of saponin was also not dependent on the state of polarization of the transverse-tubular system. 3. Treatment with saponin at concentrations up to 100 micrograms ml-1 for 30 min did not affect the Ca2+ loading ability of SR in skinned skeletal muscle fibres from the twitch portion of the toad iliofibularis muscle but SR Ca2+ loading ability decreased markedly with a time constant of 0.22 min-1 in the presence of 150 micrograms ml-1 saponin. 4. The saponin dependent increase in permeability could be reversed in both rat and toad fibres by short treatment with 6 microM Ruthenium Red, a potent SR Ca2+ channel blocker, suggesting that saponin does affect the SR Ca2+ channel properties in mammalian and anuran skeletal muscle. 5. Treatment of skinned fibres of long sarcomere length (> 6 microns) from the claw muscle of the yabby (a freshwater decapod crustacean) with 10 micrograms ml-1 saponin for 30 min abolished the ability of the SR to load Ca2+, indicating that saponin affects differently the SR from skeletal muscles of mammals, anurans and crustaceans. 6. It is concluded that at relatively low concentrations, saponin causes inhibition of the skeletal SR Ca2+ loading ability in a species

Population structure of the African Clawed Frog (Xenopus laevis) in maize-growing areas with atrazine application versus non-maize-growing areas in South Africa

USGS Publications Warehouse

Du Preez, L.H.; Solomon, K.R.; Carr, J.A.; Giesy, J.P.; Gross, T.S.; Kendall, R.J.; Smith, E.E.; Van Der Kraak, G. L.; Weldon, C.

2005-01-01

The herbicide atrazine has been suggested to cause gonadal deformities in frogs and could possibly impact on reproduction. Since the early 1960s, atrazine has been used in large amounts in maize production areas of South Africa. These areas overlap with populations of the African Clawed Frog (Xenopus laevis) that has a wide distribution in southern Africa and is found in most water-bodies including those where atrazine residues are detected. The aim of this study was to compare various attributes of individual- and population-level responses of X. laevis from maize-growing and non-maize-growing areas. Xenopus laevis were studied in three reference and five maize-growing sites. Sex ratio, snout-vent length, body-mass and age profiles were found to be similar for populations in maize-growing and non-maize-growing areas. Our mark-recapture data indicated that all sites had robust populations. There were no significant relationships between exposure to atrazine and any of the parameters investigated in populations of X. laevis.

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

USGS Publications Warehouse

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

2007-01-01

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

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

NASA Technical Reports Server (NTRS)

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

1991-01-01

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

Urocortins of the South African clawed frog, Xenopus laevis: conservation of structure and function in tetrapod evolution.

PubMed

Boorse, Graham C; Crespi, Erica J; Dautzenberg, Frank M; Denver, Robert J

2005-11-01

Several corticotropin-releasing factor (CRF) family genes have been identified in vertebrates. Mammals have four paralogous genes that encode CRF or the urocortins 1, 2, and 3. In teleost fishes, a CRF, urotensin I (a fish ortholog of mammalian urocortin 1) and urocortin 3 have been identified, suggesting that at least three of the four mammalian lineages arose in a common ancestor of modern bony fishes and tetrapods. Here we report the isolation of genes orthologous to mammalian urocortin 1 and urocortin 3 from the South African clawed frog, Xenopus laevis. We characterize the pharmacology of the frog peptides and show that X. laevis urocortin 1 binds to and activates the frog CRF1 and CRF2 receptors at picomolar concentrations. Similar to mammals, frog urocortin 3 is selective for the CRF2 receptor. Only frog urocortin 1 binds to the CRF-binding protein, although with significantly lower affinity than frog CRF. Both urocortin genes are expressed in brain, pituitary, heart, and kidney of juvenile frogs; urocortin 1 is also expressed in skin. We also identified novel urocortin sequences in the genomes of pufferfish, zebrafish, chicken, and dog. Phylogenetic analysis supports the view that four paralogous lineages of CRF-like peptides arose before the divergence of the actinopterygian and sarcopterygian fishes. Our findings show that the functional relationships among CRF ligands and binding proteins, and their anorexigenic actions mediated by the CRF2 receptor, arose early in vertebrate evolution.

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

PubMed

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

2017-07-01

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

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

USGS Publications Warehouse

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

2018-01-01

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

The structure of the cornified claw sheath in the domesticated cat (Felis catus): implications for the claw-shedding mechanism and the evolution of cornified digital end organs

PubMed Central

Homberger, Dominique G; Ham, Kyungmin; Ogunbakin, Tolulope; Bonin, Jonathan A; Hopkins, Brooke A; Osborn, Michelle L; Hossain, Imtiaz; Barnett, Heath A; Matthews, Kenneth L; Butler, Leslie G; Bragulla, Hermann H

2009-01-01

The morphology of cornified structures is notoriously difficult to analyse because of the extreme range of hardness of their component tissues. Hence, a correlative approach using light microscopy, scanning electron microscopy, three-dimensional reconstructions based on x-ray computed tomography data, and graphic modeling was applied to study the morphology of the cornified claw sheath of the domesticated cat as a model for cornified digital end organs. The highly complex architecture of the cornified claw sheath is generated by the living epidermis that is supported by the dermis and distal phalanx. The latter is characterized by an ossified unguicular hood, which overhangs the bony articular base and unguicular process of the distal phalanx and creates an unguicular recess. The dermis covers the complex surface of the bony distal phalanx but also creates special structures, such as a dorsal dermal papilla that points distally and a curved ledge on the medial and lateral sides of the unguicular process. The hard-cornified external coronary horn and proximal cone horn form the root of the cornified claw sheath within the unguicular recess, which is deeper on the dorsal side than on the medial and lateral sides. As a consequence, their rate of horn production is greater dorsally, which contributes to the overall palmo-apical curvature of the cornified claw sheath. The external coronary and proximal cone horn is worn down through normal use as it is pushed apically. The hard-cornified apical cone horn is generated by the living epidermis enveloping the base and free part of the dorsal dermal papilla. It forms nested horn cones that eventually form the core of the hardened tip of the cornified claw. The sides of the cornified claw sheath are formed by the newly described hard-cornified blade horn, which originates from the living epidermis located on the slanted face of the curved ledge. As the blade horn is moved apically, it entrains and integrates the hard

Effects of an invasive plant on population dynamics in toads.

PubMed

Greenberg, Daniel A; Green, David M

2013-10-01

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

Roughness-dependent friction force of the tarsal claw system in the beetle Pachnoda marginata (Coleoptera, Scarabaeidae).

PubMed

Dai, Zhendong; Gorb, Stanislav N; Schwarz, Uli

2002-08-01

This paper studies slide-resisting forces generated by claws in the free-walking beetle Pachnoda marginata (Coleoptera, Scarabaeoidea) with emphasis on the relationship between the dimension of the claw tip and the substrate texture. To evaluate the force range by which the claw can interact with a substrate, forces generated by the freely moving legs were measured using a load cell force transducer. To obtain information about material properties of the claw, its mechanical strength was tested in a fracture experiment, and the internal structure of the fractured claw material was studied by scanning electron microscopy. The bending stress of the claw was evaluated as 143.4-684.2 MPa, depending on the cross-section model selected. Data from these different approaches led us to propose a model explaining the saturation of friction force with increased texture roughness. The forces are determined by the relative size of the surface roughness R(a) (or an average particle diameter) and the diameter of the claw tip. When surface roughness is much bigger than the claw tip diameter, the beetle can grasp surface irregularities and generate a high degree of attachment due to mechanical interlocking with substrate texture. When R(a) is lower than or comparable to the claw tip diameter, the frictional properties of the contact between claw and substrate particles play a key role in the generation of the friction force.

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

USGS Publications Warehouse

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

2011-01-01

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

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

USGS Publications Warehouse

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

2011-01-01

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

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

NASA Technical Reports Server (NTRS)

Bingel, Bradford D.

1991-01-01

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

Fate of angiotensin I in the toad Bufo melanostictus

PubMed Central

Ng, K. K. F.

1973-01-01

1. The effects of angiotensin I and II on the blood pressure of pithed toads and the disappearance of angiotensin I and II in the perfused organs of the toad were studied. 2. Angiotensin I was relatively inactive on the blood pressure of pithed toads; it exhibited less than 3% of the pressor activity of angiotensin II. 3. Angiotensin I was not converted to angiotensin II during passage through the lungs. There was also no evidence of net conversion during passage through the kidney and hind quarters. 4. During passage through the lungs, 33-50% of angiotensin I was removed and 25-50% was removed during passage through the hind quarters. No loss of activity was detected when angiotensin II passed through the kidneys. 5. Angiotensin II passed through the lungs and kidneys without loss but 25-50% disappeared during passage through the hind quarters. 6. The relatively low pressor activity of angiotensin I together with its lack of conversion to angiotensin II in isolated perfused organs suggest that the converting enzyme is absent in the toad, Bufo melanostictus. PMID:4357961

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

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

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

1983-06-01

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

Serum and hepatic vitamin A levels in captive and wild marine toads (Bufo marinus).

PubMed

Berkvens, Charlene N; Lentini, Andrew; Dutton, Christopher J; Pearl, David L; Barker, Ian K; Crawshaw, Graham J

2014-01-01

The captive breeding program for the endangered Puerto Rican crested toad (Peltophryne [Bufo] lemur) has been hampered by an undiagnosed condition called "Brown Skin Disease" (BSD). Toads develop widespread skin darkening, skin thickening and abnormal shedding and eventually succumb to a chronic loss of viability. This project evaluated the marine toad (Bufo marinus) as a model for the PRCT, examining vitamin A deficiency as a potential cause of BSD. Wild caught marine toads had significantly higher liver vitamin A concentrations (61.89 ± 63.49 µg/g) than captive born marine toads (0.58 ± 0.59 µg/g); P<0.001). A significant difference in serum vitamin A concentration was found between the captive and wild caught toads (P=0.013) and between the low vitamin A-fed and wild caught toads (P=0.004), when controlling for liver vitamin A concentrations. After captive toads were treated with topical and/or oral vitamin A, their hepatic vitamin A concentrations were similar to those of the wild toads, averaging 48.41 ± 37.03 µg/g. However, plasma vitamin A concentrations pre- and post-vitamin A supplementation did not differ statistically. We concluded that plasma vitamin A concentrations do not provide a linear indication of liver/body vitamin A status, and that both topical and oral supplementation with an oil-based vitamin A formulation can increase liver stores in amphibians. No evidence of BSD or other signs of deficiency were noted in the marine toads, although this feeding trial was relatively short (127 days). To date, clinical, pathological and research findings do not support vitamin A deficiency as a primary factor underlying BSD. © 2014 Wiley Periodicals, Inc.

Axially aligned organic fibers and amorphous calcium phosphate form the claws of a terrestrial isopod (Crustacea).

PubMed

Vittori, Miloš; Srot, Vesna; Žagar, Kristina; Bussmann, Birgit; van Aken, Peter A; Čeh, Miran; Štrus, Jasna

2016-08-01

Skeletal elements that are exposed to heavy mechanical loads may provide important insights into the evolutionary solutions to mechanical challenges. We analyzed the microscopic architecture of dactylus claws in the woodlice Porcellio scaber and correlated these observations with analyses of the claws' mineral composition with energy dispersive X-ray spectrometry (EDX), electron energy loss spectroscopy (EELS) and selected area electron diffraction (SAED). Extraordinarily, amorphous calcium phosphate is the predominant mineral in the claw endocuticle. Unlike the strongly calcified exocuticle of the dactylus base, the claw exocuticle is devoid of mineral and is highly brominated. The architecture of the dactylus claw cuticle is drastically different from that of other parts of the exoskeleton. In contrast to the quasi-isotropic structure with chitin-protein fibers oriented in multiple directions, characteristic of the arthropod exoskeleton, the chitin-protein fibers and mineral components in the endocuticle of P. scaber claws are exclusively axially oriented. Taken together, these characteristics suggest that the claw cuticle is highly structurally anisotropic and fracture resistant and can be explained as adaptations to predominant axial loading of the thin, elongated claws. The nanoscale architecture of the isopod claw may inspire technological solutions in the design of durable machine elements subjected to heavy loading and wear. Copyright © 2016 Elsevier Inc. All rights reserved.

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

PubMed

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

2014-01-01

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

Regulation of the insulin-Akt signaling pathway and glycolysis during dehydration stress in the African clawed frog Xenopus laevis.

PubMed

Wu, Cheng-Wei; Tessier, Shannon N; Storey, Kenneth B

2017-12-01

Estivation is an adaptive stress response utilized by some amphibians during periods of drought in the summer season. In this study, we examine the regulation of the insulin signaling cascade and glycolysis pathway in the African clawed frog Xenopus laevis during the dehydration stress induced state of estivation. We show that in the brain and heart of X. laevis, dehydration reduces the phosphorylation of the insulin growth factor-1 receptor (IGF-1R), and this is followed by similar reductions in the phosphorylation of the Akt and mechanistic target of rapamycin (mTOR) kinase. Interestingly, phosphorylation levels of IGF-1R and mTOR were not affected in the kidney, and phosphorylation levels of P70S6K and the ribosomal S6 protein were elevated during dehydration stress. Animals under estivation are also susceptible to periods of hypoxia, suggesting that glycolysis may also be affected. We observed that protein levels of many glycolytic enzymes remained unchanged during dehydration; however, the hypoxia response factor-1 alpha (HIF-1α) protein was elevated by greater than twofold in the heart during dehydration. Overall, we provide evidence that shows that the insulin signaling pathway in X. laevis is regulated in a tissue-specific manner during dehydration stress and suggests an important role for this signaling cascade in mediating the estivation response.

Central Asian mountain Rhithrogenini (Ephemeroptera: Heptageniidae) with pointed and ephemeropteroid claws in the winged stages.

PubMed

Kluge, Nikita J

2015-08-03

Among mountain species of Heptageniidae from Central Asia, six species belonging to the taxa Cinygmula McDunnough 1933, Himalogena Kluge 2004 and Caucasiron Kluge 1997 have all claws of the winged stages (subimago and imago) pointed. In this area Cinygmula is represented by two species: C. hutchinsoni (Traver 1939) (with pointed claws) and C. joosti Braasch 1977 (with the more typical ephemeropteroid claws); for both species all stages of both sexes associated by rearing are redescribed. The Central Asian mountain taxon Himalogena includes seven species: Rhithrogena (Himalogena) tianshanica Brodsky 1930, Rh. (H.) pamirica sp. n., Rh. (H.) carnivora sp. n., Rh. (H.) semicarnivora sp. n., Rh. (H.) stackelbergi Sinitshenkova 1973, Rh. (H.) gunti sp. n. and Rh. (H.) nepalensis Braasch 1984; for five of them, all stages of both sexes associated by rearing are redescribed; Rh. (H.) semicarnivora is known as male imagoes reared from larvae; Rh. (H.) nepalensis formerly known only as larvae, is redescribed based on an anomalous female imago (with gynandromorphism caused by helminth in abdomen) reared from the larval stage. Among these species, Rh. (H.) tianshanica, Rh. (H.) pamirica, Rh. (H.) carnivora and Rh. (H.) semicarnivora have mandibles and the labrum modified for carnivorism, while the other three species have the usual Rhithrogena mouth apparatus. Imagoes and subimagoes of Rh. (H.) pamirica, Rh. (H.) carnivora, Rh. (H.) gunti and Rh. (H.) nepalensis, have both claws of each leg pointed, while the other species have ephemeropteroid claws. Corrections to the description of Rh. minima Sinitshenkova 1973 claw denticulation and to original figure references are given. The taxon Ironopsis/g1 is represented by two species in the Central Asian mountains: Epeorus (Caucasiron) guttatus (Braasch & Soldán 1979) (with pointed claws) and Epeorus (Ironopsis) rheophilus (Brodsky 1930) (with ephemeropteroid claws); for both species all stages of both sexes associated by rearing

Species-specific loss of sexual dimorphism in vocal effectors accompanies vocal simplification in African clawed frogs (Xenopus)

PubMed Central

Leininger, Elizabeth C.; Kitayama, Ken; Kelley, Darcy B.

2015-01-01

ABSTRACT Phylogenetic studies can reveal patterns of evolutionary change, including the gain or loss of elaborate courtship traits in males. Male African clawed frogs generally produce complex and rapid courtship vocalizations, whereas female calls are simple and slow. In a few species, however, male vocalizations are also simple and slow, suggesting loss of male-typical traits. Here, we explore features of the male vocal organ that could contribute to loss in two species with simple, slow male calls. In Xenopus boumbaensis, laryngeal morphology is more robust in males than in females. Larynges are larger, have a more complex cartilaginous morphology and contain more muscle fibers. Laryngeal muscle fibers are exclusively fast-twitch in males but are both fast- and slow-twitch in females. The laryngeal electromyogram, a measure of neuromuscular synaptic strength, shows greater potentiation in males than in females. Male-specific physiological features are shared with X. laevis, as well as with a species of the sister clade, Silurana tropicalis, and thus are likely ancestral. In X. borealis, certain aspects of laryngeal morphology and physiology are sexually monomorphic rather than dimorphic. In both sexes, laryngeal muscle fibers are of mixed-twitch type, which limits the production of muscle contractions at rapid intervals. Muscle activity potentiation and discrete tension transients resemble female rather than male X. boumbaensis. The de-masculinization of these laryngeal features suggests an alteration in sensitivity to the gonadal hormones that are known to control the sexual differentiation of the larynx in other Xenopus and Silurana species. PMID:25788725

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

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

Ward, C.; Hassan, S.; Mendonca, M.

2009-02-15

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 moremore » 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.« less

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

PubMed

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

2012-10-01

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

Sexual differences in the ecology and habitat selection of western toads (Bufo boreas) in northeastern Oregon.

Treesearch

Evelyn L. Bull

2006-01-01

Several species of toads (family Bufonidae), including the Western Toad (bufo boreas) have declined in the Western United States. Information on toad ecology and habitat use is essential to determine potential causes for population declines, as is the potential relationship between this information and disturbance events. Aspects of western toad...

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

PubMed

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

2018-06-13

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

Breeding frequency of western toads (Bufo boreas) in northeastern Oregeon

Treesearch

Evelyn L. Bull; Cynthia Carey

2008-01-01

Many species of toads (family Bufonidae), including the western toad (Bufo boreas), are declining in-the western United States. The ability of this species to recover from declines depends, in part, on its reproductive success. This study examined the breeding frequency in both sexes of B. borelis in northeastern Oregon compared to...

Pioneer identification of fake tiger claws using morphometric and DNA-based analysis in wildlife forensics in India.

PubMed

Vipin; Sharma, Vinita; Sharma, Chandra Prakash; Kumar, Ved Prakash; Goyal, Surendra Prakash

2016-09-01

The illegal trade in wildlife is a serious threat to the existence of wild animals throughout the world. The short supply and high demand for wildlife articles have caused an influx of many different forms of fake wildlife articles into this trade. The task of identifying the materials used in making such articles poses challenges in wildlife forensics as different approaches are required for species identification. Claws constitute 3.8% of the illegal animal parts (n=2899) received at the Wildlife Institute of India (WII) for species identification. We describe the identification of seized suspected tiger claws (n=18) using a combined approach of morphometric and DNA-based analysis. The differential keratin density, determined using X-ray radiographs, indicated that none of the 18 claws were of any large cat but were fake. We determined three claw measurements, viz. ac (from the external coronary dermo-epidermal interface to the epidermis of the skin fold connecting the palmar flanges of the coronary horn), bc (from the claw tip to the epidermis of the skin fold connecting the palmar flanges of the coronary horn) and the ratio bc/ac, for all the seized (n=18), tiger (n=23) and leopard (n=49) claws. Univariate and multivariate statistical analyses were performed using SPSS. A scatter plot generated using canonical discriminant function analysis revealed that of the 18 seized claws, 14 claws formed a cluster separate from the clusters of the tiger and leopard claws, whereas the remaining four claws were within the leopard cluster. Because a discrepancy was observed between the X-ray images and the measurements of these four claws, one of the claw that clustered with the leopard claws was chosen randomly and DNA analysis carried out using the cyt b (137bp) and 16S rRNA (410bp) genes. A BLAST search and comparison with the reference database at WII indicated that the keratin material of the claw was derived from Bos taurus (cattle). This is a pioneering discovery, and

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

PubMed

Phillips, Ben L; Shine, Richard

2004-12-07

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

Development and evolution of the mammalian limb: adaptive diversification of nails, hooves, and claws.

PubMed

Hamrick, M W

2001-01-01

Paleontological evidence indicates that the evolutionary diversification of mammals early in the Cenozoic era was characterized by an adaptive radiation of distal limb structures. Likewise, neontological data show that morphological variation in distal limb integumentary appendages (e.g., nails, hooves, and claws) can be observed not only among distantly related mammalian taxa but also among closely related species within the same clade. Comparative analysis of nail, claw, and hoof morphogenesis reveals relatively subtle differences in mesenchymal and epithelial patterning underlying these adult differences in distal limb appendage morphology. Furthermore, studies of regulatory gene expression during vertebrate claw development demonstrate that many of the signaling molecules involved in patterning ectodermal derivatives such as teeth, hair, and feathers are also involved in organizing mammalian distal limb appendages. For example, Bmp4 signaling plays an important role during the recruitment of mesenchymal cells into the condensations forming the terminal phalanges, whereas Msx2 affects the length of nails and claws by suppressing proliferation of germinal epidermal cells. Evolutionary changes in the form of distal integumentary appendages may therefore result from changes in gene expression during formation of mesenchymal condensations (Bmp4, posterior Hox genes), induction of the claw fold and germinal matrix (shh), and/or proliferation of epidermal cells in the claw matrix (Msx1, Msx2). The prevalence of convergences and parallelisms in nail and claw structure among mammals underscores the existence of multiple morphogenetic pathways for evolutionary change in distal limb appendages.

Impacts of Climate Change on the Global Invasion Potential of the African Clawed Frog Xenopus laevis

PubMed Central

Ihlow, Flora; Courant, Julien; Secondi, Jean; Herrel, Anthony; Rebelo, Rui; Measey, G. John; Lillo, Francesco; De Villiers, F. André; Vogt, Solveig; De Busschere, Charlotte; Backeljau, Thierry; Rödder, Dennis

2016-01-01

By altering or eliminating delicate ecological relationships, non-indigenous species are considered a major threat to biodiversity, as well as a driver of environmental change. Global climate change affects ecosystems and ecological communities, leading to changes in the phenology, geographic ranges, or population abundance of several species. Thus, predicting the impacts of global climate change on the current and future distribution of invasive species is an important subject in macroecological studies. The African clawed frog (Xenopus laevis), native to South Africa, possesses a strong invasion potential and populations have become established in numerous countries across four continents. The global invasion potential of X. laevis was assessed using correlative species distribution models (SDMs). SDMs were computed based on a comprehensive set of occurrence records covering South Africa, North America, South America and Europe and a set of nine environmental predictors. Models were built using both a maximum entropy model and an ensemble approach integrating eight algorithms. The future occurrence probabilities for X. laevis were subsequently computed using bioclimatic variables for 2070 following four different IPCC scenarios. Despite minor differences between the statistical approaches, both SDMs predict the future potential distribution of X. laevis, on a global scale, to decrease across all climate change scenarios. On a continental scale, both SDMs predict decreasing potential distributions in the species’ native range in South Africa, as well as in the invaded areas in North and South America, and in Australia where the species has not been introduced. In contrast, both SDMs predict the potential range size to expand in Europe. Our results suggest that all probability classes will be equally affected by climate change. New regional conditions may promote new invasions or the spread of established invasive populations, especially in France and Great

Impacts of Climate Change on the Global Invasion Potential of the African Clawed Frog Xenopus laevis.

PubMed

Ihlow, Flora; Courant, Julien; Secondi, Jean; Herrel, Anthony; Rebelo, Rui; Measey, G John; Lillo, Francesco; De Villiers, F André; Vogt, Solveig; De Busschere, Charlotte; Backeljau, Thierry; Rödder, Dennis

2016-01-01

By altering or eliminating delicate ecological relationships, non-indigenous species are considered a major threat to biodiversity, as well as a driver of environmental change. Global climate change affects ecosystems and ecological communities, leading to changes in the phenology, geographic ranges, or population abundance of several species. Thus, predicting the impacts of global climate change on the current and future distribution of invasive species is an important subject in macroecological studies. The African clawed frog (Xenopus laevis), native to South Africa, possesses a strong invasion potential and populations have become established in numerous countries across four continents. The global invasion potential of X. laevis was assessed using correlative species distribution models (SDMs). SDMs were computed based on a comprehensive set of occurrence records covering South Africa, North America, South America and Europe and a set of nine environmental predictors. Models were built using both a maximum entropy model and an ensemble approach integrating eight algorithms. The future occurrence probabilities for X. laevis were subsequently computed using bioclimatic variables for 2070 following four different IPCC scenarios. Despite minor differences between the statistical approaches, both SDMs predict the future potential distribution of X. laevis, on a global scale, to decrease across all climate change scenarios. On a continental scale, both SDMs predict decreasing potential distributions in the species' native range in South Africa, as well as in the invaded areas in North and South America, and in Australia where the species has not been introduced. In contrast, both SDMs predict the potential range size to expand in Europe. Our results suggest that all probability classes will be equally affected by climate change. New regional conditions may promote new invasions or the spread of established invasive populations, especially in France and Great Britain.

A Claw is Like My Hand: Comparison Supports Goal Analysis in Infants

PubMed Central

Gerson, Sarah A.; Woodward, Amanda L.

2012-01-01

Understanding the intentional relations in others' actions is critical to human social life. Origins of this knowledge exist in the first year and are a function of both acting as an intentional agent and observing movement cues in actions. We explore a new mechanism we believe plays an important role in infants' understanding of new actions: comparison. We examine how the opportunity to compare a familiar action with a novel, tool use action helps 7- and 10-month-old infants extract and imitate the goal of a tool use action. Infants given the chance to compare their own reach for a toy with an experimenter's reach using a claw later imitated the goal of an experimenter's tool use action. Infants who engaged with the claw, were familiarized with the claw's causal properties, or learned the associations between claw and toys (but did not align their reaches with the claw's) did not imitate. Further, active participation in the familiar action to be compared was more beneficial than observing a familiar and novel action aligned for 10-month-olds. Infants' ability to extract the goal-relation of a novel action through comparison with a familiar action could have a broad impact on the development of action knowledge and social learning more generally. PMID:22099543

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

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

Ward, C.K.; Appel, A.G.; Mendonca, M.T.

2006-03-15

Southern toads (Bufo terrestris) are found in coal fly ash collection basins associated with coal-burning electrical power plants. These basins contain large amounts of trace metals and organisms found in these basins are known to accumulate large quantities of metals. Studies on a variety of organisms exposed to trace metals found that they experience a significant increase in standard metabolic rate. We experimentally exposed southern toads to metal-contaminated sediment and food and measured changes in standard and exercise metabolic rates as well as changes in body, liver and muscle mass, blood glucose, and corticosterone. We found that toads exposed tomore » trace metal contamination gained significantly less mass (18.3%) than control toads (31.3%) when food was limited and experienced significantly decreased RQ after exercise. However, contaminated toads did not experience changes in standard or exercise metabolic rates, plasma glucose levels, and hepatic or muscle percentage indices whether food was limited or not.« less

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

PubMed

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

2009-08-07

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

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

PubMed

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

2017-06-01

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

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

USGS Publications Warehouse

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

2010-01-01

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

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

USGS Publications Warehouse

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

2004-01-01

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

[Healing process of claw lesions in dairy cows in alpine mountain pastures].

PubMed

Lischer, C J; Wehrle, M; Geyer, H; Lutz, B; Ossent, P

2000-07-01

The field study investigated severity, localisation and incidence of claw lesions of dairy cows and their healing process during a period of three months on selected mountain pastures in the central part of Switzerland. In 60 cows, which were at least 120 days in their lactation, the healing process was compared with the biochemical profiles. In 141 cows 197 claw lesions were recorded. Diagnosed were only sole ulcers (38%) and white line lesions (62%). In the first and second half of the summer term, the number of claw lesions was equal, although more severe lesions occurred mainly during the second half (89%). The lesions were treated surgically and the affected claw was elevated on a wood block or a plastic shoe. Average time for formation of a close layer of horn was 14 days. A delayed healing process was observed in dairy cows with an milk yield over 5500 kg per lactation, as well as in the second half of the summer term. Cows with a delayed healing process had significantly higher concentrations of free fatty acids and beta-hydroxybutyrate, and higher plasma enzyme activities for AST than cows with adequate healing process. This indicates that cows with a relatively high milk production touch upon the limits of their physical capacity under harder conditions on alpine pastures, which may affect also the healing process of claw lesions.

Measuring energetics and behaviour using accelerometry in cane toads Bufo marinus.

PubMed

Halsey, Lewis G; White, Craig R

2010-04-21

Cane toads Bufo marinus were introduced to Australia as a control agent but now have a rapidly progressing invasion front and damage new habitats they enter. Predictive models that can give expansion rates as functions of energy supply and feeding ground distribution could help to maximise control efficiency but to date no study has measured rates of field energy expenditure in an amphibian. In the present study we used the accelerometry technique to generate behavioural time budgets and, through the derivation of ODBA (overall dynamic body acceleration), to obtain estimates of energetics in free ranging cane toads. This represents the first time that accelerometers have been used to not only quantify the behaviour of animals but also assign to those behaviours rates of energy expenditure. Firstly, laboratory calibrations between ODBA and metabolic rate were obtained and used to generate a common prediction equation for the subject toads (R(2) = 0.74). Furthermore, acceleration data recorded during different behaviours was studied to ascertain threshold values for objectively defining behaviour categories. Importantly, while subsequent accelerometer field deployments were relatively short they agreed with previous studies on the proportion of time that cane toads locomote yet suggest that the metabolic rate of cane toads in the wild may sometimes be considerably higher than might be assumed based on data for other species.

Inadequate thickness of the weight-bearing surface of claws in ruminants.

PubMed

Shakespeare, A S

2009-12-01

The term 'thin soles' refers to the suboptimal thickness of the weight-bearing surface of claws in ruminants. These palmar/plantar surfaces of the claws support the weight of the animal and consist of the distal wall horn, the sole proper, the heel and the minute white line area. The sole should normally only bear weight on uneven or undulating surfaces. A decrease in the thickness of the weight-bearing claw surface will decrease the protective function of this structure and may alter the proportion of weight-bearing by each section with possible detrimental effects on hoof function. Horn tissue readily absorbs water and becomes softer which can lead to increased wear rates. Growth rates normally match wear rates but, unlike the latter, time is needed for the growth rate response to adapt to changes in wear rate. Concrete surfaces can be abrasive and dairy cows that spend their lactation cycle on these floors should be let out to pasture in the dry period so that their claws can recoup lost horn. Frictional coefficient is a measure of the'slipperiness' of hooves on various surfaces. Newly laid or fresh concrete is not only abrasive but the thin surface suspension of calcium hydroxide that forms has a very alkaline pH which causes keratin degradation and is mostly responsible for the excessive claw wear that occurs. Four case studies are used to illustrate the importance of the distal wall horn, the dangers of over-trimming and the effects of disease and concrete on horn growth and wear rates.

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

PubMed

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

2016-05-01

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

Study of progesterone and cortisol concentrations in the Italian Friesian claw.

PubMed

Comin, A; Peric, T; Magrin, L; Corazzin, M; Cornacchia, G; Prandi, A

2014-09-01

The present research was conducted to study progesterone and cortisol concentrations in the claw of cattle and to verify whether the cattle claw could be considered an efficient matrix to provide retrospective information regarding progesterone and cortisol concentrations related to pregnancy and peripartum periods. These 2 steroids are involved in hoof growth. The study was performed on 32 calves and 24 pregnant milking cows of the Holstein breed, which were clinically healthy and lacking any claw disorders. Samples of at least 0.5cm in thickness were taken from the sole. Progesterone and cortisol concentrations were determined by RIA. The cortisol concentration in the horny shoe of calves from 0 to 30 d of age was significantly higher than the concentration at 31 to 60 and 61 to 120 d of age. Conversely, the progesterone concentration showed no statistically significant difference in relation to age. The horn progesterone concentrations recorded in the milking dairy cows at 7 mo of pregnancy showed high variability in the horizontal sections of the sole (the individual coefficient of variation ranged between 0.09 and 1.11). In 6 cows, genuine extreme values (genuine outliers) of the progesterone level were found. Moreover, significant differences existed among the progesterone concentrations of the sole's transverse sections. We detected a significant positive correlation between the weight of the horn samples after freeze-drying and their weight after hydration. The cortisol and progesterone levels in soaked horn samples were found to be significantly lower than in the same dry samples. These results show that cortisol and progesterone can be measured in the cattle claw horn. The claws of mature dairy cows could not be used as a matrix to provide a retrospective measure of cumulative hormone secretion, whereas the analysis of the calves' claw horns showed retrospective hormonal information similar to hair samples. Copyright © 2014 American Dairy Science

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

PubMed

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

2016-01-01

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

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

PubMed

Muller, Benjamin J; Schwarzkopf, Lin

2017-11-01

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

Rhythm generation, coordination, and initiation in the vocal pathways of male African clawed frogs

PubMed Central

Cavin Barnes, Jessica; Appleby, Todd

2016-01-01

African clawed frogs. We discovered that two vocal phases are mediated by anatomically distinct CPGs, that there are a pair of CPGs contained in the left and right half of the brain stem, and that mechanisms underlying initiation of the two vocal phases are distinct. PMID:27760822

Effect of different flooring systems on weight and pressure distribution on claws of dairy cows.

PubMed

Telezhenko, E; Bergsten, C; Magnusson, M; Ventorp, M; Nilsson, C

2008-05-01

Weight and pressure distribution on the claw were studied in Swedish Holsteins housed in different flooring systems. A total of 127 cows housed in different sections of the experimental barn were used. Each section had different flooring in the walking and standing areas. There were rubber mats or abrasive mastic asphalt flooring on the alleys or a low-abrasive slatted concrete floor. Some sections had feed-stalls equipped with rubber mats; other sections did not. The vertical ground reaction force, contact area, and average contact pressure were determined on the left hind foot using the I-Scan system and analyzed with the F-scan system. These determinations were made in each of the following 3 zones of the claw: bulb, wall, and sole. Most of the weight on claws exposed to concrete floors was carried by the bulb (37.4 +/- 3.5 and 18.3 +/- 2.9% of weight exerted on the foot in the lateral and medial claw, respectively) and the wall zone (20.0 +/- 2.6 and 13.4 +/- 2.4% on lateral and medial claw, respectively). The weight and pressure distribution in cows kept on sections with rubber covered alleys but passing daily over the asphalt floor on their way to the milking parlor did not differ in any zones, except for lateral bulbs, compared with those exposed to slatted concrete alone. Still, the weight bearing of the sole zone in cows kept on rubber mats without access to asphalt was less than that of cows kept on concrete slatted floors (5.1 +/- 0.7 vs. 12.7 +/- 1.1% and 1.1 +/- 0.5 vs. 8.7 +/- 0.7% in lateral and medial claws, respectively). In cows kept on asphalt flooring without feed-stalls, most weight was exerted to the sole zone (36.2 +/- 2.9 and 22.2 +/- 1.8% in lateral and medial claws, respectively). Feed-stalls in combination with asphalt flooring yielded a decreased total contact area (30.1 +/- 1.2 cm(2)) compared with asphalt floors without feed-stalls (35.7 +/- 1.2 cm(2)). The largest total contact area was obtained on the asphalt floor without feed

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

PubMed

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

2011-09-01

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

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

USGS Publications Warehouse

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

2001-01-01

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

Estimation of temporary emigration in male toads

USGS Publications Warehouse

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

2006-01-01

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

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

USGS Publications Warehouse

2001-01-01

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

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

PubMed

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

2011-02-01

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

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

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-09

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

Predation by Oregon spotted frogs (Rana pretiosa) on Western toads (Bufo boreas) in Oregon, USA

USGS Publications Warehouse

Pearl, Christopher A.; Hayes, M.P.

2002-01-01

Toads of the genus Bufo co-occur with true frogs (family Ranidae) throughout their North American ranges. Yet, Bufo are rarely reported as prey for ranid frogs, perhaps due to dermal toxins that afford them protection from some predators. We report field observations from four different localities demonstrating that Oregon spotted frogs (Rana pretiosa) readily consume juvenile western toads (Bufo boreas) at breeding sites in Oregon. Unpalatability thought to deter predators of selected taxa and feeding mode may not protect juvenile stages of western toads from adult Oregon spotted frogs. Activity of juvenile western toads can elicit ambush behavior by Oregon spotted frog adults. Our review of published literature suggests that regular consumption of toadlets sets Oregon spotted frogs apart from most North American ranid frogs. Importance of the trophic context of juvenile western toads as a seasonally important resource to Oregon spotted frogs needs critical investigation.

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

PubMed

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

2017-11-01

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

Genetics, Morphology, Advertisement Calls, and Historical Records Distinguish Six New Polyploid Species of African Clawed Frog (Xenopus, Pipidae) from West and Central Africa

PubMed Central

Evans, Ben J.; Carter, Timothy F.; Greenbaum, Eli; Gvoždík, Václav; Kelley, Darcy B.; McLaughlin, Patrick J.; Pauwels, Olivier S. G.; Portik, Daniel M.; Stanley, Edward L.; Tinsley, Richard C.; Tobias, Martha L.; Blackburn, David C.

2015-01-01

African clawed frogs, genus Xenopus, are extraordinary among vertebrates in the diversity of their polyploid species and the high number of independent polyploidization events that occurred during their diversification. Here we update current understanding of the evolutionary history of this group and describe six new species from west and central sub-Saharan Africa, including four tetraploids and two dodecaploids. We provide information on molecular variation, morphology, karyotypes, vocalizations, and estimated geographic ranges, which support the distinctiveness of these new species. We resurrect Xenopus calcaratus from synonymy of Xenopus tropicalis and refer populations from Bioko Island and coastal Cameroon (near Mt. Cameroon) to this species. To facilitate comparisons to the new species, we also provide comments on the type specimens, morphology, and distributions of X. epitropicalis, X. tropicalis, and X. fraseri. This includes significantly restricted application of the names X. fraseri and X. epitropicalis, the first of which we argue is known definitively only from type specimens and possibly one other specimen. Inferring the evolutionary histories of these new species allows refinement of species groups within Xenopus and leads to our recognition of two subgenera (Xenopus and Silurana) and three species groups within the subgenus Xenopus (amieti, laevis, and muelleri species groups). PMID:26672747

Treatment of patella fracture by claw-like shape memory alloy.

PubMed

Hao, Wei; Zhou, Lugang; Sun, Yujie; Shi, Peng; Liu, Hongzhi; Wang, Xin

2015-07-01

Titanium-nickel shape memory alloy (Ti-Ni SMA) is characterized by shape-memory effect, super-elasticity, excellent fatigue behavior, corrosion resistance, acceptable biocompatibility and high damping capacity. Claw-like Ti-Ni SMA fixator (SMA-claw) has been used to treat transverse fracture of patella. 29 patients (19 males, 10 females) aged from 21 to 71 years old (averaged 43.0 years old) have been received open reduction and internal fixation with SMA-claw from January 2011 to December 2011. After operation, patients have been received gradual knee function exercises, followed by radiographic analysis and Lysholm Knee Score at 1, 2, 3, 6, 9 and 12 months postoperation. The mean follow-up time was 11.48 months (25 patients finished, 1 lost after 6 months and 3 lost after 9 months). Radiographic bone union occurred at 2 months (7 patients) or 3 months (22 patients). Satisfied range of motion for the knee joint has been observed with 1.90/141.72° (hyperextension/flexion) at 3 months, 4.83/143.97° at 6 months, 4.82/144.82° at 9 months and 5.2/145° at 12 months postsurgery. The Ti-Ni SMA-claw fixator produced good osteosynthesis effect by continuous recovery stress with relatively simple and minimally invasive handling process, which can be introduced as an alternative to traditional tension band technique for treatment of patellar transverse fracture.

Effect of rubber flooring on claw health in lactating dairy cows housed in free-stall barns.

PubMed

Vanegas, J; Overton, M; Berry, S L; Sischo, W M

2006-11-01

Multiparous dairy cows between 10 to 30 d in milk (DIM) were enrolled in a clinical trial to evaluate the effects of rubber flooring on the development of claw lesions, locomotion scores, clinical lameness, and rates of hoof growth and wear. Two groups of cows were housed in identical free-stall facilities, except that 1 pen (rubber, n = 84) had rubber alley mats covering the entire concrete floor of the pen, whereas cows in the second pen were exposed to concrete flooring (concrete, n = 82) without rubber alley mats. All cows were evaluated 3 times between 10 and 30, 74 and 94, and 110 and 130 DIM for 1) the presence of claw lesions on their rear feet, 2) the occurrence of clinical lameness based on a locomotion score, and 3) rates of claw growth and wear as observed on the dorsal wall of the right lateral claw. No differences between flooring groups at the time of enrollment were detected for lactation number, mean DIM at first examination, body condition score, and proportion of cows with claw lesions at the first examination. Odds of developing claw lesions between examinations were not different for cows exposed to the rubber surface compared with those exposed to concrete. Cows on concrete, however, had greater odds of developing or exacerbating existing heel erosion than cows on rubber flooring. Regardless of the flooring surface, the lateral claw was more likely to develop lesions than the medial claw. Odds of becoming lame by the third examination and the proportion of cows requiring therapeutic hoof trimming because of lameness were greater for concrete-exposed cows than those on rubber. Cows on rubber flooring had decreased claw growth and wear between the first and last examination compared with cows on concrete. Regardless of flooring surface, second-lactation cows had greater wear rates than those in third or greater parities. Results of our study suggest that a soft flooring surface, such as interlocking rubber, is beneficial for hoof health.

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

PubMed

Toledo, Luís Felipe; Ribeiro, Ricardo S

2009-09-01

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

In the Grip of the Scorpion Claw

NASA Image and Video Library

2010-09-21

Gripped in the claw of the constellation Scorpius sits the reflection nebula DG 129, a cloud of gas and dust that reflects light from nearby, bright stars. This infrared view of the nebula was captured by NASA Wide-field Infrared Survey Explorer.

Hybrid excited claw pole generator with skewed and non-skewed permanent magnets

NASA Astrophysics Data System (ADS)

Wardach, Marcin

2017-12-01

This article contains simulation results of the Hybrid Excited Claw Pole Generator with skewed and non-skewed permanent magnets on rotor. The experimental machine has claw poles on two rotor sections, between which an excitation control coil is located. The novelty of this machine is existence of non-skewed permanent magnets on claws of one part of the rotor and skewed permanent magnets on the second one. The paper presents the construction of the machine and analysis of the influence of the PM skewing on the cogging torque and back-emf. Simulation studies enabled the determination of the cogging torque and the back-emf rms for both: the strengthening and the weakening of magnetic field. The influence of the magnets skewing on the cogging torque and the back-emf rms have also been analyzed.

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

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

Blair, W.F.

1960-10-01

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

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

USGS Publications Warehouse

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

2011-01-01

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

Genome evolution and speciation genetics of clawed frogs (Xenopus and Silurana).

PubMed

Evans, Ben J

2008-05-01

Speciation of clawed frogs occurred through bifurcation and reticulation of evolutionary lineages, and resulted in extant species with different ploidy levels. Duplicate gene evolution and expression in these animals provides a unique perspective into the earliest genomic transformations after vertebrate whole genome duplication (WGD) and suggests that functional constraints are relaxed compared to before duplication but still consistently strong for millions of years following WGD. Additionally, extensive quantitative expression divergence between duplicate genes occurred after WGD. Diversification of clawed frogs was potentially catalyzed by transposition and divergent resolution--processes that occur through different genetic mechanisms but that have analogous implications for genome structure. How sex determination is maintained after genome duplication is fundamental to our understanding of why allopolyploidization is so prevalent in this group, and why clawed frogs violate Haldane's Rule for hybrid sterility. Future studies of expression subfunctionalization in polyploids will shed light on the role and purviews of cis- and trans-regulatory elements in gene regulation.

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

PubMed

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

1995-06-01

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

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

PubMed

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

2015-10-01

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

Effects of ammonia and hydrogen sulfide on physical and biochemical properties of the claw horn of Holstein cows

PubMed Central

Higuchi, Hidetoshi; Kurumado, Hisatoshi; Mori, Maya; Degawa, Aiko; Fujisawa, Hideyo; Kuwano, Atsutoshi; Nagahata, Hajime

2009-01-01

The effects of ammonia and hydrogen sulfide on the physical and biochemical properties of the claw horn of Holstein cows were evaluated. Significant (P < 0.05, 0.01) decreases in hardness and elasticity were found in claw horns soaked in ammonia (NH3) and hydrogen sulfide (H2S) solutions compared with those that were soaked in water for 12, 24, and 48 h. Water absorption rate, as a indicator of permeability barrier function, increased significantly (P < 0.05) over time during the soaking period and was found to be dependent on the concentrations of NH3 and H2S in the solutions. The contents of ceramide, the main lipid component for the permeability barrier system of the stratum corneum, were significantly decreased in claw horns soaked in NH3 and H2S solutions compared with the values before soaking. Quantities of eluted protein released from claw horns treated with NH3 and H2S solutions were approximately 20 times and 30 to 40 times greater than those released from claw horns treated with water alone. Interestingly, the quantities of cytokeratin 10, the main cytoskeletal protein of the stratum corneum, eluted from claw horns treated with NH3 and H2S solutions were markedly greater than the quantity released from horns soaked in water. Our results suggest that abnormal changes in the physical property of claw horn caused by NH3 and H2S treatment are due to disruption of the biochemical property of the claw horn induced by these chemical agents derived from slurry. PMID:19337390

Age-related seasonal variation in captures of stream-borne Boreal Toads (Bufo boreas boreas, Bufonidae) in western Montana

Treesearch

Michael K. Young; David A. Schmetterling

2009-01-01

Like many species of amphibians, Boreal Toads (Bufo boreas boreas, Bufonidae) are declining throughout portions of their range. Recent efforts have focused on describing the ecology of this species, yet few studies have evaluated demographic characteristics that may influence the persistence of Boreal Toad populations. Because Boreal Toads often...

Cardiovascular reflexes in conscious toads.

PubMed

Hoffmann, A; de Souza, M B

1982-05-01

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

Sudden death associated with intravenous injection of toad extract.

PubMed

Kostakis, Chris; Byard, Roger W

2009-07-01

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

Summer movements of boreal toads (Bufo boreas boreas) in two western Montana basins

Treesearch

David A. Schmetterling; Michael K. Young

2008-01-01

The Boreal Toad (Bufo boreas boreas) is widely distributed in the western United States but has declined in portions of its range. Research directed at conserving Boreal Toads has indicated that their movements are largely terrestrial and often limited after the breeding season. We used a combination of stream-based netting, PIT tagging, and radio...

Claw health and prevalence of lameness in cows from compost bedded and cubicle freestall dairy barns in Austria.

PubMed

Burgstaller, J; Raith, J; Kuchling, S; Mandl, V; Hund, A; Kofler, J

2016-10-01

Claw health and lameness data from five dairies with compost bedded barns (n = 201 data sets) were evaluated and compared with data from five dairy herds housed in freestall cubicle barns (n = 297 data sets). They were matched for having the same cow numbers, flooring type and similar milk yield. The prevalence of lameness, claw lesions and their severity grades were analysed. Two claw health indicators, the cow claw score (CCS) and the farm claw score (FCS), were calculated using a computerised claw trimming database programme; there was no significant difference in overall lameness prevalence in cows from five compost bedded barns (18.7%) compared to cows from five freestall cubicle herds (14.9%). A cumulative link mixed model (CLMM) did not show significant differences in locomotion between different types of bedding material, flooring system, breed, visit number, observer and time since last trimming, but locomotion was significantly influenced by CCS. Another CLMM tested the impact of parameters mentioned on CCS and showed significant influence of flooring type, visit number and cattle breed. Statistically significant differences in the prevalence of claw disorders between compost bedded and freestall cubicle barns were found for white line disease (WLD; 20.4% and 46.6%, respectively), heel horn erosion (HHE; 26.9% and 59.9%, respectively), concave dorsal wall as a result of chronic laminitis (6.5% and 15.9%, respectively) and for interdigital hyperplasia (0.2% and 3.1%, respectively). The results of this study indicate that compost dairy barns are a good alternative to common cubicle housing systems in terms of lameness, claw health and animal welfare. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Treesearch

Cathryn H. Greenberg; George W. Tanner

2005-01-01

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

Comparison of claw health and milk yield in dairy cows on elastic or concrete flooring.

PubMed

Kremer, P V; Nueske, S; Scholz, A M; Foerster, M

2007-10-01

This article reports on the effects of elastic (rubber) flooring compared with concrete flooring on claw health and milk yield in dairy cows. Milk yield and activity data of 53 complete lactations from 49 cows were recorded by an automatic milking system in the University of Munich Livestock Center dairy herd. Cows were kept in a loose housing system on concrete-slatted or rubber-matted slatted flooring. Claws were trimmed and measured linearly in combination with claw lesion diagnosis 3 times during one lactation period (including the transition phase). An automatic milking system recorded milk yield and activity. The net horn growth of the claws increased on elastic flooring. Therefore, correct and frequent claw trimming is at least as important for claw health in dairy herds kept on rubber flooring as for those on concrete-slatted flooring. Cows housed on rubber had an increased incidence of sole ulcers. Sole hemorrhages (except for hemorrhages associated with sole ulcers) occurred less frequently on rubber than on concrete. Results concerning digital dermatitis were difficult to assess, because manual manure scraping on rubber required sprinkling the flooring twice daily, which additionally moistened the digital skin of the cows. This might explain the greater incidence of digital dermatitis on elastic flooring. The incidence of clinically lame cows did not differ between flooring types. Cows showed greater activity on rubber, most likely caused by the more comfortable walking surface compared with the concrete-slatted flooring. The greater activity may indicate better overall health of high-yielding dairy cows on rubber flooring. Milk yield, however, did not differ between flooring types.

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

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

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

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

A combined model for Sediment TRansport In Coastal Hazard Events (GeoClaw-STRICHE): Theoretical formulation and validation

NASA Astrophysics Data System (ADS)

Tang, H.; Weiss, R.

2016-12-01

GeoClaw-STRICHE is designed for simulating the physical impacts of tsunami as it relates to erosion, transport and deposition. GeoClaw-STRICHE comprises GeoClaw for the hydrodynamics and the sediment transport model we refer to as STRICHE, which includes an advection diffusion equation as well as bed-updating. Multiple grain sizes and sediment layers are added into GeoClaw-STRICHE to simulate grain-size distribution and add the capability to develop grain-size trends from bottom to the top of a simulated deposit as well as along the inundation. Unlike previous models based on empirical equations or sediment concentration gradient, the standard Van Leer method is applied to calculate sediment flux. We tested and verified GeoClaw-STRICHE with flume experiment by Johnson et al. (2016) and data from the 2004 Indian Ocean tsunami in Kuala Meurisi as published in Apotsos et al. (2011). The comparison with experimental data shows GeoClaw-STRICHE's capability to simulate sediment thickness and grain-size distribution in experimental conditions, which builds confidence that sediment transport is correctly predicted by this model. The comparison with the data from the 2004 Indian Ocean tsunami reveals that the pattern of sediment thickness is well predicted and is of similar quality, if not better than the established computational models such as Delft3D.

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

PubMed

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

1991-01-23

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

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

PubMed Central

Caller, Georgina; Brown, Culum

2013-01-01

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

DNA "nano-claw": logic-based autonomous cancer targeting and therapy.

PubMed

You, Mingxu; Peng, Lu; Shao, Na; Zhang, Liqin; Qiu, Liping; Cui, Cheng; Tan, Weihong

2014-01-29

Cell types, both healthy and diseased, can be classified by inventories of their cell-surface markers. Programmable analysis of multiple markers would enable clinicians to develop a comprehensive disease profile, leading to more accurate diagnosis and intervention. As a first step to accomplish this, we have designed a DNA-based device, called "Nano-Claw". Combining the special structure-switching properties of DNA aptamers with toehold-mediated strand displacement reactions, this claw is capable of performing autonomous logic-based analysis of multiple cancer cell-surface markers and, in response, producing a diagnostic signal and/or targeted photodynamic therapy. We anticipate that this design can be widely applied in facilitating basic biomedical research, accurate disease diagnosis, and effective therapy.

Factors Affecting Students' Attitudes toward Toads

ERIC Educational Resources Information Center

Tomažic, Iztok; Šorgo, Andrej

2017-01-01

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

Regulation of nuclear factor of activated T cells (NFAT) and downstream myogenic proteins during dehydration in the African clawed frog.

PubMed

Zhang, Yichi; English, Simon G; Storey, Kenneth B

2018-06-19

Xenopus laevis, otherwise known as the African clawed frog, undergoes natural dehydration of up to 30% of its total body water during the dry season in sub-Saharan Africa. To survive under these conditions, a variety of physiological and biochemical changes take place in X. laevis. We were interested in understanding the role that the calcineurin-NFAT pathway plays during dehydration stress response in the skeletal muscles of X. laevis. Immunoblotting was performed to characterize the protein levels of NFATc1-4, calcium signalling proteins, in addition to myogenic proteins (MyoD, MyoG, myomaker). In addition, DNA-protein interaction ELISAs were used to assess the binding of NFATs to their consensus binding sequence, and to identify the effect of urea on NFAT-binding. Our results showed that NFATc1 and c4 protein levels decreased during dehydration, and there were no changes in NFATc2, c3, and calcium signalling proteins. However, MyoG and myomaker both showed increases in protein levels during dehydration, thus indicating that the late myogenic program involving myoblast differentiation, but not satellite cell activation and myoblast proliferation, could be involved in preserving the skeletal muscle of X. laevis during dehydration. In addition, we observed that urea seems to reduce NFATc3-binding to DNA during control, but not during dehydration, possibly indicating that NFATc3 is protected from the denaturing effects of urea as it accumulates during dehydration. These findings expand upon our knowledge of adaptive responses to dehydration, and they identify specific protein targets that could be used to protect the skeletal muscle from damage during stress.

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

PubMed

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

2018-04-01

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

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

PubMed Central

2018-01-01

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

Effect of parathyroid hormone on transport by toad and turtle bladder

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

Sabatini, S.; Kurtzman, N.A.

1987-01-01

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

Parallelization of GeoClaw code for modeling geophysical flows with adaptive mesh refinement on many-core systems

USGS Publications Warehouse

Zhang, S.; Yuen, D.A.; Zhu, A.; Song, S.; George, D.L.

2011-01-01

We parallelized the GeoClaw code on one-level grid using OpenMP in March, 2011 to meet the urgent need of simulating tsunami waves at near-shore from Tohoku 2011 and achieved over 75% of the potential speed-up on an eight core Dell Precision T7500 workstation [1]. After submitting that work to SC11 - the International Conference for High Performance Computing, we obtained an unreleased OpenMP version of GeoClaw from David George, who developed the GeoClaw code as part of his PH.D thesis. In this paper, we will show the complementary characteristics of the two approaches used in parallelizing GeoClaw and the speed-up obtained by combining the advantage of each of the two individual approaches with adaptive mesh refinement (AMR), demonstrating the capabilities of running GeoClaw efficiently on many-core systems. We will also show a novel simulation of the Tohoku 2011 Tsunami waves inundating the Sendai airport and Fukushima Nuclear Power Plants, over which the finest grid distance of 20 meters is achieved through a 4-level AMR. This simulation yields quite good predictions about the wave-heights and travel time of the tsunami waves. ?? 2011 IEEE.

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

PubMed

Wijethunga, Uditha; Greenlees, Matthew; Shine, Richard

2015-01-01

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

Reported Experiences Enhance Favourable Attitudes toward Toads

ERIC Educational Resources Information Center

Tomazic, Iztok

2011-01-01

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

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

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-09

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

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

PubMed

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

2017-11-01

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

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

PubMed

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

2017-02-01

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

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

USGS Publications Warehouse

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

2004-01-01

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

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

Treesearch

Valerie K. Hubbartt; Thomas G. Murphey

2005-01-01

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

[Proximal chemical composition and functional properties of fresh meat of crab claws (Homalaspis plana)].

PubMed

Abugoch, L; Barrios, J; Guarda, A

1996-12-01

The research of alternative technological processes is being necessary in order to obtain a better utilization of hydrobiologic resources and food products, with higher added value. Crab (Homolaspis plana) is a crustacean found along the Chilean coast, whose flesh is exported as a frozen product. The resource crab is scantly studied in Chile and could became an excellent raw material for "delicatessen" products, with a high market value. The proximal composition, through the protein, fat, moisture and ashes content was determined. The non nitrogen extract was calculated by difference. The functional properties (water retention, emulsifying and gel-forming capacities) of fresh crab claws meat without additives were measured. The proximal composition for the claw meat was: 79,34 +/- 1.12% moisture, 16.75 +/- 1.29% protein, 1.86 +/- 0.11% ashes, 0.11 +/- 0.01 fat % and 1.93 +/- 1.07% N.N.E. In relation with the emulsifying capacity, claw meat was able to emulsify 2,259.03 +/- 73.04 g vegetal oil/g protein. The water retention was 154.49 +/- 6.85% representing the increase in mass percent; and the force of the gel formed in claw meat was 195.3 +/- 17.16 g-force x cm. According to these results, the claw crab is an attractive food, with a high protein and low fat content. Crab meat showed an excellent emulsifying capacity and water retention, so it can be used as a good raw material for the development of smearing products. In the case of gel-like products, further studies will be required, in order to optimize the conditions in which a stronger gel could be obtained.

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

PubMed

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

2007-11-01

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

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

PubMed

Brown, Gregory P; Shine, Richard

2014-01-01

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

Urotensin II receptor (UTR) exists in hyaline chondrocytes: a study of peripheral distribution of UTR in the African clawed frog, Xenopus laevis.

PubMed

Konno, Norifumi; Fujii, Yuya; Imae, Haruka; Kaiya, Hiroyuki; Mukuda, Takao; Miyazato, Mikiya; Matsuda, Kouhei; Uchiyama, Minoru

2013-05-01

Urotensin II (UII) and UII-related peptide (URP) exhibit diverse physiological actions including vasoconstriction, locomotor activity, osmoregulation, and immune response through UII receptor (UTR), which is expressed in the central nervous system and peripheral tissues of fish and mammals. In amphibians, only UII has been identified. As the first step toward elucidating the actions of UII and URP in amphibians, we cloned and characterized URP and UTR from the African clawed frog Xenopus laevis. Functional analysis showed that treatment of UII or URP with Chinese hamster ovary cells transfected with the cloned receptor increased the intracellular calcium concentration in a concentration-dependent manner, whereas the administration of the UTR antagonist urantide inhibited UII- or URP-induced Ca(2+) mobilization. An immunohistochemical study showed that UTR was expressed in the splenocytes and leukocytes isolated from peripheral blood, suggesting that UII and URP are involved in the regulation of the immune system. UTR was also localized in the apical membrane of the distal tubule of the kidney and in the transitional epithelial cells of the urinary bladder. This result supports the view that the UII/URP-UTR system plays an important role in osmoregulation of amphibians. Interestingly, immunopositive labeling for UTR was first detected in the chondrocytes of various hyaline cartilages (the lung septa, interphalangeal joint and sternum). The expression of UTR was also observed in the costal cartilage, tracheal cartilages, and xiphoid process of the rat. These novel findings probably suggest that UII and URP mediate the formation of the cartilaginous matrix. Copyright © 2013 Elsevier Inc. All rights reserved.

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

PubMed

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

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

Transcriptome profiling of claw muscle of the mud crab (Scylla paramamosain) at different fattening stages

PubMed Central

Jiang, Qingling; Bao, Chenchang; Yang, Ya’nan; Liu, An; Liu, Fang; Huang, Huiyang; Ye, Haihui

2017-01-01

In crustaceans, muscle growth and development is complicated, and to date substantial knowledge gaps exist. In this study, the claw muscle, hepatopancreas and nervous tissue of the mud crab (Scylla paramamosain) were collected at three fattening stages for sequence by the Illumina sequencing. A total of 127.87 Gb clean data with no less than 3.94 Gb generated for each sample and the cycleQ30 percentages were more than 86.13% for all samples. De Bruijn assembly of these clean data produced 94,853 unigenes, thereinto, 50,059 unigenes were found in claw muscle. A total of 121 differentially expressed genes (DEGs) were revealed in claw muscle from the three fattening stages with a Padj value < 0.01, including 63 genes with annotation. Functional annotation and enrichment analysis showed that the DEGs clusters represented the predominant gene catalog with roles in biochemical processes (glycolysis, phosphorylation and regulation of transcription), molecular function (ATP binding, 6-phosphofructokinase activity, and sequence-specific DNA binding) and cellular component (6-phosphofructokinase complex, plasma membrane, and integral component of membrane). qRT-PCR was employed to further validate certain DEGs. Single nucleotide polymorphism (SNP) analysis obtained 159,322, 125,963 and 166,279 potential SNPs from the muscle transcriptome at stage B, stage C and stage D, respectively. In addition, there were sixteen neuropeptide transcripts being predicted in the claw muscle. The present study provides a comprehensive transcriptome of claw muscle of S. paramamosain during fattening, providing a basis for screening the functional genes that may affect muscle growth of S. paramamosain. PMID:29141033

Effect of rubber flooring on group-housed sows' gait and claw and skin lesions.

PubMed

Bos, E-J; van Riet, M M J; Maes, D; Millet, S; Ampe, B; Janssens, G P J; Tuyttens, F A M

2016-05-01

This study evaluated the influence of floor type on sow welfare in terms of lameness, claw lesions, and skin lesions. In a 2 × 3 factorial design, we have investigated the effect of rubber coverings on concrete floors and the effect of 3 levels of dietary zinc supplementation on locomotion and claw and skin lesions in group-housed sows. Six groups of 21 ± 4 hybrid sows were monitored during 3 successive reproductive cycles. The sows were group housed from d 28 after insemination (d 0) until 1 wk before expected farrowing date (d 108) in pens with either exposed concrete floors or concrete floors covered with rubber in part of the lying area and the fully slatted area. During each reproductive cycle, locomotion and skin lesions were assessed 4 times (d 28, 50, 108, and 140) and claw lesions were assessed twice (d 50 and 140). Results are given as least squares means ± SE. Locomotion and claw scores were given in millimeters, on analog scales of 150 and 160 mm, respectively. Here, we report on the effect of floor type, which did not interact with dietary zinc concentration ( > 0.10 for all variables). At move to group (d 28) and mid gestation (d 50), no differences between floor treatments were seen in locomotion ( > 0.10). At the end of gestation (d 108), sows housed on rubber flooring scored 9.9 ± 4.1 mm better on gait ( < 0.001). Regarding claw disorders, both parameters "heel overgrowth and erosion" (difference of 4.6 ± 1.8 mm; = 0.01) and "heel-sole crack" (difference of 3.1 ± 1.5 mm; = 0.04) scores were better for sows on rubber flooring at mid gestation (d 50). However, sows on rubber flooring scored worse for "vertical cracks in the wall horn" (difference of 3.4 ± 1.7 mm; = 0.04). At the end of lactation (d 140), both "white line" (difference of 2.9 ± 1 mm; = 0.02) and "claw length" (difference of 4.7 ± 1.4 mm; < 0.001) had better scores on rubber flooring. No differences for skin lesions were observed between floor treatments. The improved scores

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

USGS Publications Warehouse

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

2001-01-01

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

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

PubMed Central

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

2013-01-01

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

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

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

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

1991-04-01

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

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

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

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

1992-01-01

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

Influence of Soft or Hard Floors before and after First Calving on Dairy Heifer Locomotion, Claw and Leg Health

PubMed Central

Bergsten, Christer; Telezhenko, Evgenij; Ventorp, Michael

2015-01-01

Simple Summary In this study the effect of different flooring systems on locomotion, claw conformation, loading, claw- and leg disorders was assessed in heifers from one year before to one year after calving. After calving, heifers kept on alleys covered with rubber flooring were found to develop less lameness, fewer claw disorders of the sole horn and fewer leg lesions than those kept on concrete alleys. Recruitment heifers reared on soft deep straw bedding had fewer sole horn lesions and more overgrown claws before calving, but were more prone to severe sole horn lesions after calving, than those reared in cubicles with hard concrete floors. Abstract Claw health, an important dairy cow welfare parameter, may be affected by early-life foot/leg stresses. To investigate this, groups of pregnant heifers were allocated to deep straw bedding (Soft) or cubicles (Hard), both with scraped concrete feeding alleys. After the grazing season, they were re-housed in cubicle systems, half on slatted concrete (Hard) and half on slatted rubber (Soft) alleys. Claw measurements, contact area and pressure distribution claw/flooring, claw disorders and leg lesions were recorded at the start and end of each housing season. Locomotion and leg lesions were also scored monthly after calving. Prevalence of sole haemorrhages was higher among pregnant heifers in cubicles than in deep straw. After calving, first-calvers on Hard floors had higher odds for lameness (OR = 3.6; p < 0.01), sole haemorrhages/ulcers (OR = 2.2; p < 0.05), white-line haemorrhages (OR = 2.8; p < 0.01) and leg lesions (OR = 2.6; p < 0.02) than those on Soft floors. Lowest prevalence and severity of sole and white-line haemorrhages (non-significant) in first-calvers was found in those on Soft floors and reared on Hard floors and the highest prevalence and severity on those on Hard floors reared on Soft floors. Soft flooring after calving is of most importance for healthy feet and legs. PMID:26479380

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

PubMed

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

2018-05-01

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

Retropupillary fixation of iris-claw lens in visual rehabilitation of aphakic eyes.

PubMed

Jayamadhury, G; Potti, Sudhakar; Kumar, K Vinaya; Kumar, R Madhu; Divyansh Mishra, K C; Nambula, Srinivasa Rao

2016-10-01

Surgical outcome of retropupillary fixation of iris claw lens. To evaluate the various indications, intra and post-operative complications, and visual outcome of retropupillary fixation of iris claw lens in aphakic eyes. The study design is a retrospective study at a tertiary eye care center. Review of medical records of 61 aphakic eyes of 61 patients, who were rehabilitated with retropupillary fixation of an iris claw lens, with a follow-up duration of at least 1 year. Data analysis was performed using paired t-test and Chi-square test. Mean preoperative uncorrected visual acuity was 1.66 ± 0.3 LogMAR and postoperative acuity at 1 year was 0.53 ± 0.5 LogMAR (P = 0.00001). Preoperative distant best-corrected visual acuity was 0.30 ± 0.48 LogMAR and postoperative acuity at 1 year was 0.27 ± 0.46 LogMAR (P = 0.07). Mean preoperative astigmatism was 1.43 ± 1.94 D and postoperatively was 1.85 ± 2.16 D (P = 0.0127). Mean endothelial cell count was 2353.52 ± 614 cells/mm2 preoperatively which decreased to 2200 ± 728 cells/mm2 at 1 year follow-up (P = 0.006). There was no significant difference in central macular thickness and intraocular pressure pre and post-surgery. Complications included ovalization of pupil in 9.83%, hypotony in 1.63%, toxic anterior segment syndrome in 1.63%, cystoid macular edema in 11.47%, epiretinal membrane in 3.27%, and iris atrophy in 6.55%. Iris claw is a safe and an effective method of rehabilitating aphakic eyes.

Instream movements by boreal toads (Bufo boreas boreas)

Treesearch

Susan B. Adams; David A. Schmetterling; Michael K. Young

2005-01-01

Determining the nature and extent of bufonid movements is critical to understanding the autecology of each species, as well as to developing effective conservation strategies. Within many toad (Bufo spp.) populations, individuals must migrate considerable distances to reach habitats essential for fulfilling requirements that change seasonally and...

Habitat modeling and movements of the Yosemite toad (Anaxyrus (=Bufo) canorus) in the Sierra Nevada, California

Treesearch

C.T. Liang

2010-01-01

The Yosemite toad (Anaxyrus (=Bufo) canorus) is a high-elevation species endemic to the Sierra Nevada mountain range in California and is part of the world-wide amphibian declines phenomenon. The toad is thought to have disappeared from over 50% of its historic range even in seemingly undisturbed areas, and...

Management of bipseudophakia with implantation of an iris claw lens.

PubMed

Izak, Milan G J; Werner, Liliana; Izak, Andrea M; Apple, David J

2003-07-01

We discuss a case of bipseudophakia with secondary dislocation of a posterior chamber intraocular lens (IOL) into the anterior chamber that was managed by explantation of the anterior and posterior chamber IOLs and implantation of an iris claw IOL.

Quantitative evaluation of the relationship between dorsal wall length, sole thickness, and rotation of the distal phalanx in the bovine claw using computed tomography.

PubMed

Tsuka, T; Murahata, Y; Azuma, K; Osaki, T; Ito, N; Okamoto, Y; Imagawa, T

2014-10-01

Computed tomography (CT) was performed on 800 untrimmed claws (400 inner claws and 400 outer claws) of 200 pairs of bovine hindlimbs to investigate the relationships between dorsal wall length and sole thickness, and between dorsal wall length and the relative rotation angle of distal phalanx-to-sole surface (S-D angle). Sole thickness was 3.8 and 4.0 mm at the apex of the inner claws and outer claws, respectively, with dorsal wall lengths <70 mm. These sole thickness values were less than the critical limit of 5 mm, which is associated with a softer surface following thinning of the soles. A sole thickness of 5 mm at the apex was estimated to correlate with dorsal wall lengths of 72.1 and 72.7 mm for the inner and outer claws, respectively. Sole thickness was 6.1 and 6.4 mm at the apex of the inner and outer claws, respectively, with dorsal wall lengths of 75 mm. These sole thickness values were less than the recommended sole thickness of 7 mm based on the protective function of the soles. A sole thickness >7 mm at the apex was estimated to correlate with a dorsal wall length of 79.8 and 78.4mm for the inner and outer claws, respectively. The S-D angles were recorded as anteversions of 2.9° and 4.7° for the inner and outer claws, respectively, with a dorsal wall length of 75 mm. These values indicate that the distal phalanx is likely to have rotated naturally forward toward the sole surface. The distal phalanx rotated backward to the sole surface at 3.2° and 7.6° for inner claws with dorsal wall lengths of 90-99 and ≥100 mm, respectively; and at 3.5° for outer claws with a dorsal wall length ≥100 mm. Dorsal wall lengths of 85.7 and 97.2 mm were estimated to correlate with a parallel positional relationship of the distal phalanx to the sole surface in the inner and outer claws, respectively. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

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

USGS Publications Warehouse

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

2010-01-01

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

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

USGS Publications Warehouse

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

2008-01-01

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

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

USGS Publications Warehouse

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

2013-01-01

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

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

PubMed

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

1996-08-01

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

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

PubMed Central

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

2017-01-01

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

Lameness and Claw Lesions of the Norwegian Red Dairy Cattle Housed in Free Stalls in Relation to Environment, Parity and Stage of Lactation

PubMed Central

Sogstad, ÅM; Fjeldaas, T; Østerås, O

2005-01-01

Approximately 88% of Norwegian dairy cattle are housed in tie stalls. Free stall housing for all dairy cattle will be implemented within 20 years. This means that the majority of existing stalls will be rebuilt in the near future. Fifty-seven free stall herds of the Norwegian Red breed were randomly selected and 1547 cows and 403 heifers were trimmed by 13 claw trimmers during the late winter and spring of 2002. The claw trimmers had been taught diagnosing and recording of claw lesions. Environment, management- and feeding routines were also recorded. Fifty-three herds had concrete slatted alleys while 4 had solid concrete. Thirty-five herds had concrete as a stall base, while 17 had rubber mats, 2 had wood and 3 had deep litter straw beds. The prevalence of lameness was 1.6% in hind claws. Models for lameness and claw lesions were designed to estimate the influence of different risk factors and to account for the cluster effects within herd and claw trimmer. Detected risk factors for lameness were: parity three and above and narrow cubicles; for heel horn erosions: lactation stage around 5–7 months after calving and solid concrete alleys; for haemorrhages of the white line: lactation stage around 3–5 months after calving and solid concrete alleys; for haemorrhages of the sole: parity one, lactation stage around 5–7 months after calving and short cubicles, for white line fissures: slatted concrete alleys; for asymmetrical claws: parities two and above and for corkscrewed claws: solid concrete alleys. The prevalence of lameness in heifers was low, however 29% had one or more claw lesions. Heifers that were housed in pens or free stalls had more heel-horn erosions, haemorrhages of the sole and white-line fissures than heifers in tie stalls. As new free stalls are being built, it is important to optimise the conditions for claw health. PMID:16398332

Effects of alley and stall surfaces on indices of claw and leg health in dairy cattle housed in a free-stall barn.

PubMed

Vokey, F J; Guard, C L; Erb, H N; Galton, D M

2001-12-01

A 15-wk 2 x 3 factorial trial in a university dairy herd compared the effects of two alley surfaces and three free-stall beds on indices of lameness. Alley surfaces were grooved concrete (Ct) or 1.9-cm-thick interlocking rubber mats (R). Stalls were deep sand (S), rubber mattresses (M), or concrete (C). Mattress and concrete stalls were bedded with sawdust. At wk 1 and 15, the hind claws and hocks of 120 primi- (n = 69) and multiparous (n = 51) cows were scored for lesions and three claw measurements (dorsal wall length, heel depth, and toe angle) were recorded. Rates of lateral and medial claw growth and wear were calculated by measuring the migration of a reference mark away from the coronet. Digital photographs of claw surfaces were used to rescore claw lesions. Clinical lameness was evaluated by assigning a locomotion score from 1 to 4 to each cow during wk 1, 5, 10, and 14. Digital dermatitis (present/not present) and interdigital dermatitis (mild, moderate, or severe) were recorded at wk 15. The number of days that cows spent in a hospital barn was recorded. Before assignment, cows were professionally foot trimmed, sorted by initial claw lesion score, and then randomized in consecutive blocks of three to stall treatments. Photograph scores were highly repeatable. Nonparametric statistical techniques were used for analyses of rank data. Claw lesion score increased significantly for all treatment groups except RC and RS; however, when early lactation cows were excluded, no differences were found between treatment groups. Hock scores increased significantly more for cows in CtC than in CtS or RS. Significantly more animals from RC spent more than 10 d in the hospital pen compared with RM and RS. Groups did not significantly differ for clinical lameness. Cows in RS and RC had significantly lower rates for lateral claw net growth than those in CtM. Having moderate or severe interdigital dermatitis at wk 15 was associated with greater increases in claw lesion score

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

Treesearch

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

2009-01-01

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

Effect of claw horn lesion type and severity at the time of treatment on outcome of lameness in dairy cows.

PubMed

Miguel-Pacheco, Giuliana G; Thomas, Heather J; Huxley, Jonathan N; Newsome, Reuben F; Kaler, Jasmeet

2017-07-01

Prompt diagnosis and treatment of claw horn lesions in cattle affects the likelihood of recovery; however, it is unknown if the type of lesion influences the likelihood of recovery. The aim of this study was to investigate whether the type, severity and frequency of claw horn lesions in newly lame cows (lame for no more than 2 weeks) at the time of corrective foot trimming affects the probability of recovery from lameness after treatment. The images of 112 feet (224 claws) from newly lame cows (n=112; lame in only one hind foot), which were treated with a standardised therapeutic hoof trim only, were used to score claw horn lesions (sole ulcer, sole haemorrhage, white line haemorrhage or white line separation). Most cows (n=107/112; 95.5%) were classified as mildly lame at the time of treatment. The proportion of cows that recovered 2 weeks after therapeutic hoof trimming was 88/112 (78.6%). Results of a multilevel logistic regression model indicated that severely lame cows were less likely to recover than those that were mildly lame (odds ratio, OR, 0.16; P=0.04). White line haemorrhage had a significant negative impact on the likelihood of recovery from lameness (OR 0.14; P>0.01); however, recovery of cows with white line haemorrhage was positively associated with the length of the lesion (OR 1.05; P=0.03). This latter finding may be associated with the severity of the lesion, since mild claw horn lesions affected a significantly larger area of the claw than more severe lesions. The length and type of claw horn lesion were associated with recovery from lameness. Copyright © 2017 Elsevier Ltd. All rights reserved.

WEAKLY SYNCHRYRONIZED SUBPOPULATION DYNAMICS IN WISCONSIN FROGS AND TOADS

EPA Science Inventory

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

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

USGS Publications Warehouse

Dodd, C.K.

1994-01-01

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

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

PubMed

Johnson, W E; Propper, C R

2000-05-01

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

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

PubMed

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

2014-09-01

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

DIET OF THE SOUTHERN TOAD FROM THE SOUTHERN EVERGLADES

EPA Science Inventory

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

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

PubMed Central

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

2018-01-01

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

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

PubMed

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

2017-01-01

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

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

PubMed

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

2017-01-01

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

Locomotion and claw disorders in Norwegian dairy cows housed in freestalls with slatted concrete, solid concrete, or solid rubber flooring in the alleys.

PubMed

Fjeldaas, T; Sogstad, A M; Osterås, O

2011-03-01

This study was part of a cross-sectional project on freestall housing, and the aim was to compare locomotion and claw disorders in freestall dairy cattle herds with slatted concrete, solid concrete, or solid rubber flooring in the alleys. The final population for studying claw disorders consisted of 66 dairy herds with 2,709 dry or lactating cows, whereas the population for studying locomotion consisted of 54 herds with 2,216 cows. All herds used Norwegian Red as the main breed. The herds were visited by 15 trained claw trimmers one time during the period from the beginning of February to summer let-out onto pasture in 2008. The trimmers assessed locomotion scores (LocS) of all cows before trimming. At trimming, claw disorders were diagnosed and recorded in the Norwegian Claw Health Card. Estimates describing locomotion and claw disorders in the hind feet were identified by use of multivariable models fit with LocS and each claw disorder as dependent variables, respectively. Herd nested within claw trimmer was included in the model as random effects. The odds ratio (OR) of having LocS >2 and LocS >3 was 1.9 and 2.1, respectively, on slatted concrete compared with solid concrete. Fewer cases of dermatitis were found on slatted than solid concrete (OR=0.70) and a tendency was observed for fewer heel horn erosions on slatted concrete than solid rubber (OR=0.47). Hemorrhages of the white line and sole were more prevalent in herds housed on slatted and solid concrete than in those housed on solid rubber (OR=2.6 and OR=2.1, respectively). White line fissures were also more prevalent in herds housed on slatted and solid concrete than in those housed on solid rubber (OR=2.1 and OR=2.0, respectively). Double soles were more prevalent on solid concrete than solid rubber (OR=4.4). However, sole ulcers were less prevalent in herds with slatted and solid concrete than solid rubber (OR=0.39 and OR=0.53, respectively). Fewer corkscrewed claws were found on slatted concrete than

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

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

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

2004-09-13

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

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

PubMed

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

2001-05-01

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

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

USGS Publications Warehouse

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

2015-01-01

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

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

USGS Publications Warehouse

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

2011-01-01

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

Determinants of Instrumental Extinction in Terrestrial Toads ("Bufo arenarum")

ERIC Educational Resources Information Center

Muzio, Ruben N.; Ruetti, Eliana; Papini, Mauricio R.

2006-01-01

Previous research in a water-reinforced instrumental training situation with toads ("Bufo arenarum") has shown that performance in both acquisition and extinction is poorer after partial, rather than continuous reinforcement training. In Experiment 1, the performance of a group receiving 24 trials on a 50% partial reinforcement schedule was poorer…

Iris reconstruction combined with iris-claw intraocular lens implantation for the management of iris-lens injured patients.

PubMed

Hu, Shufang; Wang, Mingling; Xiao, Tianlin; Zhao, Zhenquan

2016-03-01

To study the efficiency and safety of iris reconstruction combined with iris-claw intraocular lens (IOL) implantation in the patients with iris-lens injuries. Retrospective, noncomparable consecutive case series study. Eleven patients (11 eyes) following iris-lens injuries underwent iris reconstructions combined with iris-claw IOL implantations. Clinical data, such as cause and time of injury, visual acuity (VA), iris and lens injuries, surgical intervention, follow-up period, corneal endothelial cell count, and optical coherence tomography, were collected. Uncorrected VA (UCVA) in all injured eyes before combined surgery was equal to or <20/1000. Within a 1.1-4.2-year follow-up period, a significant increase, equal to or better than 20/66, in UCVA was observed in six (55%) cases, and in best-corrected VA (BCVA) was observed in nine (82%) cases. Postoperative BCVA was 20/40 or better in seven cases (64%). After combined surgery, the iris returned to its natural round shape or smaller pupil, and the iris-claw IOLs in the 11 eyes were well-positioned on the anterior surface of reconstructed iris. No complications occurred in those patients. Iris reconstruction combined with iris-claw IOL implantation is a safe and efficient procedure for an eye with iris-lens injury in the absence of capsular support.

Clawed forelimbs allow northern seals to eat like their ancient ancestors

NASA Astrophysics Data System (ADS)

Hocking, David P.; Marx, Felix G.; Sattler, Renae; Harris, Robert N.; Pollock, Tahlia I.; Sorrell, Karina J.; Fitzgerald, Erich M. G.; McCurry, Matthew R.; Evans, Alistair R.

2018-04-01

Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name `pinniped' comes from the Latin pinna and pedis, meaning `fin-footed'. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. `Hold and tear' processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos. Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding.

Clawed forelimbs allow northern seals to eat like their ancient ancestors.

PubMed

Hocking, David P; Marx, Felix G; Sattler, Renae; Harris, Robert N; Pollock, Tahlia I; Sorrell, Karina J; Fitzgerald, Erich M G; McCurry, Matthew R; Evans, Alistair R

2018-04-01

Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name 'pinniped' comes from the Latin pinna and pedis , meaning 'fin-footed'. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. 'Hold and tear' processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos . Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding.

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

USGS Publications Warehouse

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

2000-01-01

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

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

PubMed

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

1992-04-01

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

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

PubMed Central

Gonzalez, Jonathan; Takeuchi, Hirohiko; Mori, Akira

2016-01-01

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

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

USGS Publications Warehouse

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

2008-01-01

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

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

PubMed

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

2016-11-16

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

The clinical application of absorbable intramedullary nail and claw plate on treating multiple rib fractures.

PubMed

Chai, X; Lin, Q; Ruan, Z; Zheng, J; Zhou, J; Zhang, J

2013-08-01

The absorption intramedullary nail and claw plate indications and efficacy were investigated in the treatment of a life-threatening multiple rib fractures. A retrospective analysis of 248 surgically treated rib fracture patients was performed who admitted to our hospital from March 2007 to December 2012. Intramedullary nailing was performed in 28 cases, a claw-type bone plate was fixed in 141 cases, and a combination of both was fixed in 79 cases. All internal fixation patients were clinically cured except 1 patient died 14 days after a massive pulmonary embolism. The patients with flail chest and floating chest wall causing respiratory and circulatory disorders were promptly corrected. Routine follow-up was from 1 to 2 years, displaced fractures were in 2 cases, and there were 11 cases of internal fixation and extraction. Internal fixation is a simple and reliable method for the treatment of multiple rib fractures. Both internal fixation materials have their pros and cons but the claw bone plate is more robust. The actual selection of appropriate treatment options helps to improve the treatment efficacy.

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

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

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

1988-03-01

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

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

PubMed

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

1992-01-01

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

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

USGS Publications Warehouse

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

2009-01-01

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

Primary iris claw IOL retrofixation with intravitreal triamcinolone acetonide in cases of inadequate capsular support.

PubMed

Kelkar, Aditya; Shah, Rachana; Vasavda, Viraj; Kelkar, Jai; Kelkar, Shreekant

2018-02-01

To assess the outcomes and analyze complication rates following primary iris claw IOL retrofixation with intravitreal triamcinolone acetonide. This is a retrospective interventional case series. Patients with poor capsular support-diagnosed preoperatively or owing to intraoperative complications-were treated with iris claw IOL retrofixation with intravitreal triamcinolone acetonide. The data were retrospectively analyzed. 104 eyes of 102 patients with poor capsular support who underwent the procedure between 2010 and 2013 were analyzed. The minimum follow-up period was 12 months (ranging from 12 to 36 months). Iris claw IOL was implanted in-traumatic subluxated cataracts-24 cases (23.07%), non-traumatic subluxated cataracts in 16 cases (15.38%), or as a complication of cataract surgery-intraoperative posterior capsular rent in 48 cases (46.15%) and intraoperative nucleus drop in 16 cases (15.38%). The final mean best-corrected logMAR visual acuity improved from 1.36 ± 0.64 preoperatively to 0.36 ± 0.32 at 1-year follow-up. Complications included pupil ovalization in 11 cases (10.57%), transient elevation in intraocular pressure in 7 eyes (6.73%), postoperative hypotony in 5 eyes (4.80%), cystoid macular edema in 2 eyes (1.92%), retinal detachment in 1 eye (0.96%), vitreous hemorrhage in 1 eye (0.96%), and hyphema in 1 eye (0.96%). Primary iris claw IOL retrofixation provided excellent alternative in patients with inadequate capsular support. The visual outcomes were good along with favorable rates of complications. The addition of triamcinolone acetonide helps in reducing the chances of cystoid macular edema.

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

PubMed Central

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

2011-01-01

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

Clawed forelimbs allow northern seals to eat like their ancient ancestors

PubMed Central

Sattler, Renae; Harris, Robert N.; Pollock, Tahlia I.; Sorrell, Karina J.; Fitzgerald, Erich M. G.; McCurry, Matthew R.

2018-01-01

Streamlined flippers are often considered the defining feature of seals and sea lions, whose very name ‘pinniped’ comes from the Latin pinna and pedis, meaning ‘fin-footed’. Yet not all pinniped limbs are alike. Whereas otariids (fur seals and sea lions) possess stiff streamlined forelimb flippers, phocine seals (northern true seals) have retained a webbed yet mobile paw bearing sharp claws. Here, we show that captive and wild phocines routinely use these claws to secure prey during processing, enabling seals to tear large fish by stretching them between their teeth and forelimbs. ‘Hold and tear’ processing relies on the primitive forelimb anatomy displayed by phocines, which is also found in the early fossil pinniped Enaliarctos. Phocine forelimb anatomy and behaviour therefore provide a glimpse into how the earliest seals likely fed, and indicate what behaviours may have assisted pinnipeds along their journey from terrestrial to aquatic feeding. PMID:29765684

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

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

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

1987-01-01

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

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

USGS Publications Warehouse

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

2011-01-01

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

Iris reconstruction combined with iris-claw intraocular lens implantation for the management of iris-lens injured patients

PubMed Central

Hu, Shufang; Wang, Mingling; Xiao, Tianlin; Zhao, Zhenquan

2016-01-01

Aim: To study the efficiency and safety of iris reconstruction combined with iris-claw intraocular lens (IOL) implantation in the patients with iris-lens injuries. Settings and Design: Retrospective, noncomparable consecutive case series study. Materials and Methods: Eleven patients (11 eyes) following iris-lens injuries underwent iris reconstructions combined with iris-claw IOL implantations. Clinical data, such as cause and time of injury, visual acuity (VA), iris and lens injuries, surgical intervention, follow-up period, corneal endothelial cell count, and optical coherence tomography, were collected. Results: Uncorrected VA (UCVA) in all injured eyes before combined surgery was equal to or <20/1000. Within a 1.1–4.2-year follow-up period, a significant increase, equal to or better than 20/66, in UCVA was observed in six (55%) cases, and in best-corrected VA (BCVA) was observed in nine (82%) cases. Postoperative BCVA was 20/40 or better in seven cases (64%). After combined surgery, the iris returned to its natural round shape or smaller pupil, and the iris-claw IOLs in the 11 eyes were well-positioned on the anterior surface of reconstructed iris. No complications occurred in those patients. Conclusions: Iris reconstruction combined with iris-claw IOL implantation is a safe and efficient procedure for an eye with iris-lens injury in the absence of capsular support. PMID:27146932

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

PubMed

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

2016-07-01

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

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

PubMed

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

2014-04-01

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

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

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

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

1976-05-17

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

Genetic evaluation of claw health traits accounting for potential preselection of cows to be trimmed.

PubMed

Croué, Iola; Fikse, Freddy; Johansson, Kjell; Carlén, Emma; Thomas, Gilles; Leclerc, Hélène; Ducrocq, Vincent

2017-10-01

Claw lesions are one of the most important health issues in dairy cattle. Although the frequency of claw lesions depends greatly on herd management, the frequency can be lowered through genetic selection. A genetic evaluation could be developed based on trimming records collected by claw trimmers; however, not all cows present in a herd are usually selected by the breeder to be trimmed. The objectives of this study were to investigate the importance of the preselection of cows for trimming, to account for this preselection, and to estimate genetic parameters of claw health traits. The final data set contained 25,511 trimming records of French Holstein cows. Analyzed claw lesion traits were digital dermatitis, heel horn erosion, interdigital hyperplasia, sole hemorrhage circumscribed, sole hemorrhage diffused, sole ulcer, and white line fissure. All traits were analyzed as binary traits in a multitrait linear animal model. Three scenarios were considered: including only trimmed cows in a 7-trait model (scenario 1); or trimmed cows and contemporary cows not trimmed but present at the time of a visit (considering that nontrimmed cows were healthy) in a 7-trait model (scenario 2); or trimmed cows and contemporary cows not trimmed but present at the time of a visit (considering lesion records for trimmed cows only), in an 8-trait model, including a 0/1 trimming status trait (scenario 3). For scenario 3, heritability estimates ranged from 0.02 to 0.09 on the observed scale. Genetic correlations clearly revealed 2 groups of traits (digital dermatitis, heel horn erosion, and interdigital hyperplasia on the one hand, and sole hemorrhage circumscribed, sole hemorrhage diffused, sole ulcer, and white line fissure on the other hand). Heritabilities on the underlying scale did not vary much depending on the scenario: the effect of the preselection of cows for trimming on the estimation of heritabilities appeared to be negligible. However, including untrimmed cows as healthy

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

PubMed

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

2016-09-10

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

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

USGS Publications Warehouse

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

2009-01-01

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

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

PubMed

Narayan, Edward J; Hero, Jean-Marc

2014-01-01

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

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

PubMed Central

Narayan, Edward J.; Hero, Jean-Marc

2014-01-01

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

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

PubMed Central

Hanner, R H; Ryan, G B

1980-01-01

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

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

PubMed Central

1980-01-01

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

Polyploidy in the common tree toad Hyla versicolor Le Conte.

PubMed

Wasserman, A O

1970-01-23

A karyotype of the first known naturally occurring anuran polyploid in North America is described. Hyla versicolor, the common tree toad, is tetraploid (2n-->4n=48). Individual chromosmes representing, each set of four of the Hyla versicolor karyotype correspond closely with those of the diploid (2n = 24) Hyla andersonii karyotype.

Effect of trace mineral source on lactation performance, claw integrity, and fertility of dairy cattle.

PubMed

Siciliano-Jones, J L; Socha, M T; Tomlinson, D J; DeFrain, J M

2008-05-01

Two hundred fifty multiparous and primiparous cows were assigned to a study at approximately 70 d prepartum to determine the effect of trace mineral source on lactation performance, claw integrity, and fertility. Cows received treatments from 3 wk prepartum through wk 35 postpartum. Treatments consisted of 1) all supplemental Zn, Mn, Cu, and Co provided in sulfate form (Sulfate) and 2) 360 mg of Zn, 200 mg of Mn, 125 mg of Cu, and 12 mg of Co supplied daily by Sulfate minerals replaced with similar amounts of minerals supplied by Availa-4 (CTM). Individuals involved with daily animal care or data recording, or both, were blinded to treatment assignments. Cows from all treatments were housed in common pens, and treatments were dispensed to cows via a computerized feeder. All claws of cows were examined before treatment administration and at 16 and 36 wk postpartum by personnel trained in identifying claw lesions. Cows fed the CTM diet tended to produce more milk and energy-corrected milk than cows fed the Sulfate diet. Cows fed the CTM diet also produced more milk protein and solids (fat + protein) than cows fed the Sulfate diet. Replacing Sulfate minerals with those supplied by CTM decreased incidence of sole ulcers at wk 36 postpartum and tended to decrease incidence of interdigital dermatitis at wk 16 and 36 postpartum. Severity of heel erosion tended to be less for cows fed CTM than cows receiving the Sulfate diet. Despite first service conception rates tending to be greater for cows fed the Sulfate diet, there was no effect of treatment on rate of conception. A greater percentage of cows fed the Sulfate diet tended to be culled from the herd before wk 36 postpartum than cows fed the CTM diet. Replacing Sulfate minerals with CTM resulted in improved lactation performance and claw integrity.

Tooth, hair and claw: comparing epithelial stem cell niches of ectodermal appendages

PubMed Central

Naveau, Adrien; Seidel, Kerstin; Klein, Ophir D.

2014-01-01

The vertebrate ectoderm gives rise to organs that produce mineralized or keratinized substances, including teeth, hair, and claws. Most of these ectodermal derivatives grow continuously throughout the animal’s life and have active pools of adult stem cells that generate all the necessary cell types. These organs provide powerful systems for understanding the mechanisms that enable stem cells to regenerate or renew ectodermally derived tissues, and remarkable progress in our understanding of these systems has been made in recent years using mouse models. We briefly compare what is known about stem cells and their niches in incisors, hair follicles, and claws, and we examine expression of Gli1 as a potential example of a shared stem cell marker. We summarize some of the features, structures, and functions of the stem cell niches in these ectodermal derivatives; definition of the basic elements of the stem cell niches in these organs will provide guiding principles for identification and characterization of the niche in similar systems. PMID:24530577

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

EPA Science Inventory

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

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

PubMed

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

2016-11-01

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

Better late than never: effective air-borne hearing of toads delayed by late maturation of the tympanic middle ear structures.

PubMed

Womack, Molly C; Christensen-Dalsgaard, Jakob; Hoke, Kim L

2016-10-15

Most vertebrates have evolved a tympanic middle ear that enables effective hearing of airborne sound on land. Although inner ears develop during the tadpole stages of toads, tympanic middle ear structures are not complete until months after metamorphosis, potentially limiting the sensitivity of post-metamorphic juveniles to sounds in their environment. We tested the hearing of five species of toads to determine how delayed ear development impairs airborne auditory sensitivity. We performed auditory brainstem recordings to test the hearing of the toads and used micro-computed tomography and histology to relate the development of ear structures to hearing ability. We found a large (14-27 dB) increase in hearing sensitivity from 900 to 2500 Hz over the course of ear development. Thickening of the tympanic annulus cartilage and full ossification of the middle ear bone are associated with increased hearing ability in the final stages of ear maturation. Thus, juvenile toads are at a hearing disadvantage, at least in the high-frequency range, throughout much of their development, because late-forming ear elements are critical to middle ear function at these frequencies. We discuss the potential fitness consequences of late hearing development, although research directly addressing selective pressures on hearing sensitivity across ontogeny is lacking. Given that most vertebrate sensory systems function very early in life, toad tympanic hearing may be a sensory development anomaly. © 2016. Published by The Company of Biologists Ltd.

Outbreak of common midwife toad virus in alpine newts (Mesotriton alpestris cyreni) and common midwife toads (Alytes obstetricans) in northern Spain: a comparative pathological study of an emerging ranavirus.

PubMed

Balseiro, Ana; Dalton, Kevin P; del Cerro, Ana; Márquez, Isabel; Parra, Francisco; Prieto, José M; Casais, R

2010-11-01

This report describes the isolation and characterisation of the common midwife toad virus (CMTV) from juvenile alpine newts (Mesotriton alpestris cyreni) and common midwife toad (CMT) tadpoles (Alytes obstetricans) in the Picos de Europa National Park in Northern Spain in August 2008. A comparative pathological and immunohistochemical study was carried out using anti-CMTV polyclonal serum. In the kidneys, glomeruli had the most severe histological lesions in CMT tadpoles, while both glomeruli and renal tubular epithelial cells exhibited foci of necrosis in juvenile alpine newts. Viral antigens were detected by immunohistochemical labelling mainly in the kidneys of CMT tadpoles and in ganglia of juvenile alpine newts. This is the first report of ranavirus infection in the alpine newt, the second known species to be affected by CMTV in the past 2 years. Copyright © 2009 Elsevier Ltd. All rights reserved.

Conservation in the Teaching Laboratory--Substitution of Xenopus for Rana.

ERIC Educational Resources Information Center

Bernhart, David M; And Others

1991-01-01

Reports on experimental comparisons between the leopard frog, currently captured for laboratory use, and the African clawed frog, raised specifically for research. Except for the increased longevity of isolated nerve axons in the clawed frog, no other significant differences were established. Recommends laboratory use of clawed frogs as…

Residue depletion of oxytetracycline (OTC) and 4-epi-oxytetracycline (4-epi-OTC) in broiler chicken's claws by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

PubMed

Cornejo, J; Pokrant, E; Araya, D; Briceño, C; Hidalgo, H; Maddaleno, A; Araya-Jordán, C; San Martin, B

2017-04-01

Antibiotics are widely used in poultry production for the treatment of bacterial diseases. However, residues may remain in products and by-products destined for human consumption or animal feeding. The claws of chickens, which are a by-product of the poultry industry, can directly or indirectly enter the food chain as meals destined to feed other productive animals. Thus, it becomes necessary to determine and quantify antimicrobial residues present in this matrix. The objective of the study was to assess the depletion of oxytetracycline (OTC) and its metabolite 4-epi-OTC in broiler chicken's claws. Claws of 32 broilers treated with a therapeutic dosage of 10% OTC during 7 days were analysed. Samples were taken at days 3, 9, 15 and 19 post-treatment. As for the control group, eight broiler chickens were raised under the same conditions. Extraction was carried out through EDTA-McIlvaine buffer, and clean-up employed a SPE C-18 Sep-Pak®. Instrumental analysis was performed through LC-MS/MS. The concentrations of both analytes were determined in claw samples until day 19 post-treatment. Average concentrations were within the LOD (20 μg kg - 1 ) and LOQ (22 µg kg - 1 ) for OTC and 84 μg kg - 1 for 4-epi-OTC. Withdrawal times (WDTs) of 39 days for OTC and 54 days for 4-epi-OTC were established in claws based on 95% confidence. These findings demonstrate that claws can be a source of antimicrobial residue entry into the food chain, since the results showed that OTC and its metabolite can be found in chicken's claws for long periods, even exceeding the average lifespan of a broiler chicken.

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

Treesearch

Christina T. Liang; Thomas J. Stohlgren

2011-01-01

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

A burrowing frog from the late Paleocene of Mongolia uncovers a deep history of spadefoot toads (Pelobatoidea) in East Asia.

PubMed

Chen, Jianye; Bever, Gaberiel S; Yi, Hong-Yu; Norell, Mark A

2016-01-11

Fossils are indispensible in understanding the evolutionary origins of the modern fauna. Crown-group spadefoot toads (Anura: Pelobatoidea) are the best-known fossorial frog clade to inhabit arid environments, with species utilizing a characteristic bony spade on their foot for burrowing. Endemic to the Northern Hemisphere, they are distributed across the Holarctic except East Asia. Here we report a rare fossil of a crown-group spadefoot toad from the late Paleocene of Mongolia. The phylogenetic analysis using both morphological and molecular information recovered this Asian fossil inside the modern North American pelobatoid clade Scaphiopodidae. The presence of a spade and the phylogenetic position of the new fossil frog strongly support its burrowing behavior. The late Paleocene age and other information suggestive of a mild climate cast doubt on the conventional assertion that burrowing evolved as an adaptation to aridity in spadefoot toads. Temporally and geographically, the new fossil provides the earliest record of Scaphiopodidae worldwide, and the only member of the group in Asia. Quantitative biogeographic analysis suggests that Scaphiopodidae, despite originating in North America, dispersed into East Asia via Beringia in the Early Cenozoic. The absence of spadefoot toads in East Asia today is a result of extinction.

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

PubMed

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

2012-01-15

Urinary corticosterone metabolite enzyme-immunoassay (EIA) can be used for the non-invasive assessment of baseline levels and corticosterone responses in amphibians. In this study, urinary corticosterone responses of wild male cane toads (Rhinella marina) to confinement and repeated handling were measured to quantify individual variation in corticosterone responses for the first time in an amphibian species. Urine samples were collected at 0 h in the wild, hourly from 2 to 8 h after transfer into captivity, and again at 12 and 24 h in captivity. Toads were then held in captivity and subjected to the same sampling protocol on three occasions at 14 days intervals to quantify variation in corticosterone metabolite responses within and between toads. Baseline and individual corticosterone metabolite responses in male cane toads were generally consistent, with high statistical repeatabilities for 0 h (r=0.630), 6 h (r=0.793), 12 h (r=0.652) and 24 h (r=0.721) corticosterone metabolite concentrations, and for the total and corrected integrated corticosterone responses (r=0.567, p=0.033; r=0.728, p=0.014 respectively). Urinary corticosterone responses appear to be a stable, repeatable trait within individuals. Corticosterone responses in amphibians can be more readily measured when urine rather than plasma samples are collected, and the protocol established in the current study can now be applied to the study of variation in corticosterone responses in other amphibians. Copyright © 2011 Elsevier Inc. All rights reserved.

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

Treesearch

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

2008-01-01

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

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

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

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

2007-05-15

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

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

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

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

2005-04-01

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

Development of a superconducting claw-pole linear test-rig

NASA Astrophysics Data System (ADS)

Radyjowski, Patryk; Keysan, Ozan; Burchell, Joseph; Mueller, Markus

2016-04-01

Superconducting generators can help to reduce the cost of energy for large offshore wind turbines, where the size and mass of the generator have a direct effect on the installation cost. However, existing superconducting generators are not as reliable as the alternative technologies. In this paper, a linear test prototype for a novel superconducting claw-pole topology, which has a stationary superconducting coil that eliminates the cryocooler coupler will be presented. The issues related to mechanical, electromagnetic and thermal aspects of the prototype will be presented.

Isotomidae (Collembola) of Buryat Republic. III. The genera Vertagopus and Agrenia, with a note on 'Claw index'.

PubMed

Potapov, Mikhail; Gulgenova, Ayuna; Babykina, Marina

2016-03-07

Two genera are revised based on material from Buryatia (Russia, East Siberia). Vertagopus ceratus sp. nov. and V. asiaticus sp. nov. are described of which the former species is strictly alpine and is defined by pale colouration, the presence of chaetae on the anterior side of the ventral tube, and abundant sensillar chaetotaxy. V. asiaticus sp. nov. is widely distributed in Asia and is unusual due to only 9 chaetae in apical whorl on tibiotarsi. A key to species of Vertagopus Börner, recorded in the republic is given, and notes on morphology, distribution, and ecology are provided. In the genus Agrenia Börner, a form similar with A. bidenticulata was recorded in mountainous areas. Buryatian populations considerably differ from the diagnosis of the typical arctic A.bidenticulata (Tullberg) by a much longer claw. A conception of A. bidenticulata sensu lato complex is temporarily proposed basing on available materials from Palearctic, including High Arctic, sub-Arctic and South Siberian mountains. The complex consists of several local forms which are different in Claw index and associated Tibiotarsus/Claw ratio, while the dependence of the two indexes on the latitude is shown.

Inhibition of basolateral cAMP permeability in the toad urinary bladder.

PubMed

Boom, A; Golstein, P E; Frerotte, M; Sande, J V; Beauwens, R

2000-10-01

1. The effect of sulphonylurea drugs on hydrosmotic flow across toad urinary bladder epithelium was re-evaluated in the present study. Glibenclamide, added to the basolateral medium, significantly enhanced the osmotic flow induced by low doses of antidiuretic hormone (ADH) or forskolin (FK), while it inhibited the effect of exogenous cyclic adenosine monophosphate (cAMP) or its non-hydrolysable bromo derivative, 8-Br-cAMP, added to the basolateral medium. These opposite effects of glibenclamide on the transepithelial osmotic flow can be explained by a reduction of cAMP permeability across the basolateral membrane of the epithelium. The decrease in cAMP permeability leads, according to the direction of the cAMP gradient, to firstly an enhanced osmotic flow when cAMP is generated intracellularly by addition of ADH and FK, glibenclamide reducing cAMP exit from the cell, and secondly a decreased osmotic flow in response to cAMP (and 8-Br-cAMP) added to the basolateral medium, glibenclamide inhibiting, in this case, their entry into the cell. 2. The demonstration that glibenclamide actually inhibits the basolateral cAMP permeability rests on the fact that firstly it decreases the release of cAMP into the basolateral medium by about 40 %, at each concentration of ADH or forskolin tested, secondly it increases the cAMP content of paired hemibladders incubated in the presence of ADH or FK, when intracellular degradation was prevented by phosphodiesterase inhibition, and thirdly it decreases also the uptake of basolateral 8-Br-[3H]cAMP into paired toad hemibladders. 3. Taken together, the present data demonstrate that glibenclamide inhibits the toad urinary bladder basolateral membrane permeability to cAMP, most probably by a direct interaction with a membrane protein not yet indentified but distinct from the sulphonylurea receptor.

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

PubMed Central

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

2006-01-01

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

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

PubMed Central

2010-01-01

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

Hybridization between the African clawed frogs Xenopus laevis and Xenopus muelleri (Pipidae) increases the multiplicity of antimicrobial peptides in skin secretions of female offspring.

PubMed

Mechkarska, Milena; Meetani, Mohammed; Michalak, Pawel; Vaksman, Zalman; Takada, Koji; Conlon, J Michael

2012-09-01

Peptidomic analysis was used to compare the distribution of host-defense peptides in norepinephrine-stimulated skin secretions from laboratory-generated female F1 hybrids of the common clawed frog Xenopus laevis (Daudin, 1802) and Mueller's clawed frog Xenopus muelleri (Peters, 1844) with the corresponding distribution in skin secretions from the parent species. A total of 18 peptides were identified in secretions from the hybrid frogs. Eleven peptides (magainin-1, magainin-2, CPF-1, CPF-3, CPF-4, CPF-5, CPF-6, CPF-7, XPF-1, XPF-2, and PGLa) were identified in secretions of both the hybrids and X. laevis. Four peptides (magainin-M1, XPF-M1, CPF-M1, and tigerinin-M1) were previously found in skin secretions of X. muelleri but magainin-M2 and CPF-M2 from X. muelleri were not detected. Three previously undescribed peptides (magainin-LM1, PGLa-LM1, and CPF-LM1) were purified from the secretions of the hybrid frogs that were not detected in secretions from either X. laevis or X. muelleri. Magainin-LM1 differs from magainin-2 from X. laevis by a single amino acid substitution (Gly(13)→Ala) but PGLa-LM1 and CPF-LM1 differ appreciably in structure from orthologs in the parent species. CPF-LM1 shows potent, broad-spectrum antimicrobial activity and is hemolytic. The data indicate that hybridization increases the multiplicity of skin host-defense peptides in skin secretions. As the female F1 hybrids are fertile, hybridization may represent an adaptive strategy among Xenopus species to increase protection against pathogenic microorganisms in the environment. Copyright © 2012 Elsevier Inc. All rights reserved.

Lethal and sub-lethal effects on the Asian common toad Duttaphrynus melanostictus from exposure to hexavalent chromium.

PubMed

Fernando, Vindhya A K; Weerasena, Jagathpriya; Lakraj, G Pemantha; Perera, Inoka C; Dangalle, Chandima D; Handunnetti, Shiroma; Premawansa, Sunil; Wijesinghe, Mayuri R

2016-08-01

Chromium discharged in industrial effluents frequently occurs as an environmental pollutant, but the lethal and sub-lethal effects the heavy metal might cause in animals exposed to it have been insufficiently investigated. Selecting the amphibian Duttaphrynus melanostictus, we carried out laboratory tests to investigate the effects of short and long term exposure to hexavalent chromium (Cr(VI)) in both tadpoles and adult toads. The concentrations used were 0.002, 0.02, 0.2, 1.0 and 2.0mg/L, the first three corresponding to field levels. In vitro exposures were also carried out using toad erythrocytes and Cr(VI) concentrations of 0.0015, 0.003, 0.015, 0.03, 0.15mg/L. Mortality, growth retardation, developmental delays and structural aberrations were noted in the metal-treated tadpoles, with increasing incidence corresponding to increase in Cr(VI) level and duration of exposure. Many of the sub-lethal effects were evident with long term exposure to environmentally relevant levels of the toxicant. Changes in selected blood parameters and erythrocyte morphometry were also detected in Cr(VI) exposed toads, indicating anaemic and leucopenic conditions. In the genotoxicity study, DNA damage indicated by comet assay and increased micronuclei frequency, occurred at the low Cr(VI) concentrations tested. The multiple deleterious effects of exposure to chromium signal the need for monitoring and controlling the discharge of chromium to the environment. The dose-dependency and genotoxic effects observed in this widely distributed Asian toad indicates its suitability for monitoring heavy metal pollution in aquatic systems. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of flooring and restricted freestall access on behavior and claw health of dairy heifers.

PubMed

Ouweltjes, W; van der Werf, J T N; Frankena, K; van Leeuwen, J L

2011-02-01

Claw health, locomotion, feed intake, milk yield, body weight, activity, and lying and standing behavior of dairy heifers were monitored in a single dairy herd during the first 3 mo after calving. During the first 8 wk after calving, 2 treatments were applied: restricted freestall access by closing the stalls between 2300 h and 0500 h (yes or no) and alley flooring (concrete or rubber topped slatted floors). Apart from treatments, housing was identical. The animals were kept in small groups (n=4 to 6) in adjacent barn pens. Thereafter, the animals were kept in 1 group in a freestall section with concrete slatted floor and unrestricted access to the stalls for 5 wk. All animals were fed the same partial mixed ration. We hypothesized that (1) hard flooring causes high mechanical load of the claws and (2) restricted freestall access causes prolonged standing bouts and reinforced effects of hard flooring on claws. The heifers had only minor claw lesions before first calving, and the prevalence and severity of sole hemorrhages increased during the first 3 mo after calving (from 0.24 ± 0.08 to 1.18 ± 0.14 and from 0.04 ± 0.01 to 0.24 ± 0.02, respectively), particularly in the outer hind claws. Animals kept on rubber alley flooring had lower average hemorrhage scores in wk 9 (0.13 ± 0.03 vs. 0.21 ± 0.03) and wk 14 (0.20 ± 0.03 vs. 0.27 ± 0.03) after calving, had a slower feed intake (3.05 ± 0.14 vs. 3.46 ± 0.14 g/s) and spent more time feeding (7.3 ± 0.3 vs. 6.6 ± 0.3 min/h) than animals kept on hard concrete alley floors. Restricted freestall access resulted in fewer standing bouts per day (14.4 ± 1.0 vs. 17.9 ± 1.0) and more strides per hour (99.8 ± 5.4 vs. 87.2 ± 5.4) without changing overall standing time (15.0 ± 0.3 vs. 14.7 ± 0.3 h/d) and did not affect the occurrence of sole hemorrhages. The animals with no overnight freestall access spent more time standing (55.9 ± 0.9 vs. 35.8 ± 0.9 min/h) and feeding (7.8 ± 0.3 vs. 4.3 ± 0.3 min/h) between

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

PubMed

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

2003-06-01

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

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

Treesearch

Cathryn H. Greenberg; George W. Tanner

2005-01-01

Effective amphibian conservation must consider population and landscape processes, but information at multiple scales is rare. We explore spatial and temporal patterns of breeding and recruitment by eastern spadefoot toads (Scaphiopus holbrookii), using nine years of data from continuous monitoring with drift fences and pitfall traps at eight...

Estradiol and reproduction in the South American toad Rhinella arenarum (Amphibian, Anura).

PubMed

Scaia, María Florencia; Volonteri, María Clara; Czuchlej, Silvia Cristina; Ceballos, Nora Raquel

2018-03-16

Rhinella arenarum is a South American toad with wide geographic distribution. Testes of this toad produce high amount of androgens during the non reproductive season and shift steroid synthesis from androgens to 5α-pregnanedione during the breeding. In addition, plasma estradiol (E 2 ) in males of this species shows seasonal variations but, since testes of R. arenarum do not express aromatase, the source of plasma E 2 remained unknown for several years. However, the Bidder's organ (BO), a structure located at one pole of each testis, is proposed to be the main source of E 2 in male's toads since it expresses several steroidogenic enzymes and is able to produce E 2 from endogenous substrates throughout the year. In addition, there were significant correlations between plasma E 2 and total activity of BO aromatase, and between plasma E 2 and the amount of hormone produced by the BO in vitro. In the toad, apoptosis induced by in vitro treatment with E 2 was mostly detected in spermatocytes during the breeding and in spermatids during the post-reproductive season, suggesting that this steroid has an important role in controlling spermatogenesis. However, in vitro treatment with E 2 had no effect on proliferation. This evidence suggests that the mechanism of action of E 2 on amphibian spermatogenesis is complex and more studies are necessary to fully understand the role of estrogens regulating the balance between cellular proliferation and apoptosis. In addition, in R. arenarum in vitro studies suggested that E 2 has no effect on CypP450c17 protein levels or enzymatic activity, while it reduces 3β-hydroxysteroid dehydrogenase/isomerase (3β-HSD/I) activity during the post reproductive season. As well, E 2 regulates FSHβ mRNA expression all over the year suggesting a down regulation process carried out by this steroid. The effect on LHβ mRNA is dual, since during the reproductive season estradiol increases the expression of LHβ mRNA while in the non

Bufo canorus Camp 1916, Yosemite Toad.

USGS Publications Warehouse

Davidson, Carlos; Fellers, Gary M.; Lannoo, Michael

2005-01-01

Yosemite toads (Bufo canorus) are endemic to the Sierra Nevada, California, from Ebbetts Pass, Alpine County to the Spanish Mountain area, Fresno County (Karlstrom 1962, 1973; Stebbins 1966; unpublished Sierra National Forest survey data, 1995, 2002). Sites occur from 1,950–3,444 m elevation, with the majority of sites between 2,590–3,048 m (Karlstrom, 1962). Jennings and Hayes (1994a) estimate that populations have disappeared from 50% of historically reported sites, although the overall range of the species may have only contracted in the far north and in western Fresno County. Disappearances have been concentrated at lower elevation sites on the western edge of the range, with greater persistence at higher elevation sites (Davidson et al., 2002).

Retropupillary iris-claw intraocular lens for the surgical correction of aphakia in cases with microspherophakia.

PubMed

Fouda, Sameh Mosaad; Al Aswad, Mahmoud A; Ibrahim, Basem M; Bori, Ashraf; Mattout, Hala K

2016-12-01

This study aimed to evaluate the safety and efficacy of retropupillary fixation of an iris-claw intraocular lens (IOL; Verisyse polymethyl methacrylate IOL, Abbott Medical Optics [AMO], Netherlands) for the surgical correction of aphakia in microspherophakic eyes without sufficient capsular support. This was a prospective, interventional, noncomparative case series. This interventional case series comprised 17 eyes of 9 microspherophakic patients. Retropupillary fixation of the Verisyse iris-claw IOL (AMO) was performed in all cases. The surgical time was measured. Corrected distance visual acuity, astigmatism, intraocular pressure (IOP), tissue reaction, pigment dispersion, and stability of the IOL were studied 1 day, 3 days, 1 week, 2 weeks, 1 month, and 6 months postoperatively. Eight patients had familial microspherophakia and one patient had Marfan's syndrome. Eighty-two percent of the cases achieved a visual acuity of 0.3 or better. There was no significant postoperative inflammatory reaction. Transient elevation of IOP was recorded in two cases in the 1st week only. One IOL developed disengagement of one of the haptics from the iris and was successfully re-engaged. All the other IOLs were well centered and stable. The mean surgical time was 18.0 ± 4.5 min. Retropupillary fixation of an iris-claw IOL is a safe and effective procedure that provides early visual recovery. It is also a time-saving method for correcting aphakia in microspherophakic eyes without sufficient capsular support.

Behaviour of the Pleistocene marsupial lion deduced from claw marks in a southwestern Australian cave.

PubMed

Arman, Samuel D; Prideaux, Gavin J

2016-02-15

The marsupial lion, Thylacoleo carnifex, was the largest-ever marsupial carnivore, and is one of the most iconic extinct Australian vertebrates. With a highly-specialised dentition, powerful forelimbs and a robust build, its overall morphology is not approached by any other mammal. However, despite >150 years of attention, fundamental aspects of its biology remain unresolved. Here we analyse an assemblage of claw marks preserved on surfaces in a cave and deduce that they were generated by marsupial lions. The distribution and skewed size range of claw marks within the cave elucidate two key aspects of marsupial lion biology: they were excellent climbers and reared young in caves. Scrutiny of >10,000 co-located Pleistocene bones reveals few if any marsupial lion tooth marks, which dovetails with the morphology-based interpretation of the species as a flesh specialist.

Assigning king eiders to wintering regions in the Bering Sea using stable isotopes of feathers and claws

USGS Publications Warehouse

Oppel, S.; Powell, A.N.

2008-01-01

Identification of wintering regions for birds sampled during the breeding season is crucial to understanding how events outside the breeding season may affect populations. We assigned king eiders captured on breeding grounds in northern Alaska to 3 broad geographic wintering regions in the Bering Sea using stable carbon and nitrogen isotopes obtained from head feathers. Using a discriminant function analysis of feathers obtained from birds tracked with satellite transmitters, we estimated that 88 % of feathers were assigned to the region in which they were grown. We then assigned 84 birds of unknown origin to wintering regions based on their head feather isotope ratios, and tested the utility of claws for geographic assignment. Based on the feather results, we estimated that similar proportions of birds in our study area use each of the 3 wintering regions in the Bering Sea. These results are in close agreement with estimates from satellite telemetry and show the usefulness of stable isotope signatures of feathers in assigning marine birds to geographic regions. The use of claws is currently limited by incomplete understanding of claw growth rates. Data presented here will allow managers of eiders, other marine birds, and marine mammals to assign animals to regions in the Bering Sea based on stable isotope signatures of body tissues. ?? Inter-Research 2008.

Portrait of a small population of boreal toads (anaxyrus boreas)

USGS Publications Warehouse

Muths, E.; Scherer, R. D.

2011-01-01

Much attention has been given to the conservation of small populations, those that are small because of decline, and those that are naturally small. Small populations are of particular interest because ecological theory suggests that they are vulnerable to the deleterious effects of environmental, demographic, and genetic stochasticity as well as natural and human-induced catastrophes. However, testing theory and developing applicable conservation measures for small populations is hampered by sparse data. This lack of information is frequently driven by computational issues with small data sets that can be confounded by the impacts of stressors. We present estimates of demographic parameters from a small population of Boreal Toads (Anaxyrus boreas) that has been surveyed since 2001 by using capturerecapture methods. Estimates of annual adult survival probability are high relative to other Boreal Toad populations, whereas estimates of recruitment rate are low. Despite using simple models, clear patterns emerged from the analyses, suggesting that population size is constrained by low recruitment of adults and is declining slowly. These patterns provide insights that are useful in developing management directions for this small population, and this study serves as an example of the potential for small populations to yield robust and useful information despite sample size constraints. ?? 2011 The Herpetologists' League, Inc.

Portrait of a small population of boreal toads (Anaxyrus boreas)

USGS Publications Warehouse

Muths, Erin; Scherer, Rick D.

2011-01-01

Much attention has been given to the conservation of small populations, those that are small because of decline, and those that are naturally small. Small populations are of particular interest because ecological theory suggests that they are vulnerable to the deleterious effects of environmental, demographic, and genetic stochasticity as well as natural and human-induced catastrophes. However, testing theory and developing applicable conservation measures for small populations is hampered by sparse data. This lack of information is frequently driven by computational issues with small data sets that can be confounded by the impacts of stressors. We present estimates of demographic parameters from a small population of Boreal Toads (Anaxyrus boreas) that has been surveyed since 2001 by using capture-recapture methods. Estimates of annual adult survival probability are high relative to other Boreal Toad populations, whereas estimates of recruitment rate are low. Despite using simple models, clear patterns emerged from the analyses, suggesting that population size is constrained by low recruitment of adults and is declining slowly. These patterns provide insights that are useful in developing management directions for this small population, and this study serves as an example of the potential for small populations to yield robust and useful information despite sample size constraints.

Splenic immunotoxicity in developing cane toads (Rhinella marina) from Bermuda.

PubMed

Fort, Douglas J; Mathis, Michael; Fort, Chelsea E; Fort, Hayley M; Fort, Troy D; Linzey, Donald W; Bacon, Jamie P

2016-10-01

The impacts of contaminated sediment from 2 ponds in Bermuda on immune function in newly metamorphosed cane toads were examined. In the present study, a partial life-cycle experiment exposing Gosner stage 20 cane toad tadpoles to pond sediment and laboratory culture water through metamorphosis and into a juvenile state was performed. A basic immunology battery, including general necropsy, spleen somatic index, spleen white pulp content, splenocyte tissue density, and splenocyte viability, was conducted in newly metamorphosed Rhinella marina exposed to Bermuda freshwater sediment and baseline specimens collected from 2 separate populations in south Texas and south Florida, USA. Immune function was evaluated using a lymphocyte proliferation assay with subset specimens infected with Mycobacterium chelonae. In the Bermuda population exposed to pond sediment, splenocyte tissue density was markedly lower and lymphocyte proliferation substantially less relative to cohorts exposed to control sediment and to the North American populations. Considerable increases in spleen weight and liver and spleen lesions related to M. chelonae infection were recorded in challenged Bermuda R. marina compared with unchallenged specimens. Overall, immune function in Bermuda R. marina was compromised compared with North American mainland R. marina regardless of treatment but more dramatically in specimens exposed to Bermuda pond sediments. Environ Toxicol Chem 2016;35:2604-2612. © 2016 SETAC. © 2016 SETAC.

[Influence of the Concentration of Dissolved Oxygen on Embryonic Development of the Common Toad (Bufo bufo)].

PubMed

Dmitrieva, E V

2015-01-01

Several series of experiments investigating the influence of dissolved oxygen concentrations on the growth rates and mortality in the embryogenesis of the common toad Bufo bufo were carried out. The experiments showed that, when the eggs develop singly, the lack of oxygen does not lead to an increase in mortality by the time of hatching and results only in a change in the dynamics of mortality: mortality occurs at an earlier stage of development than in the conditions of normal access to oxygen. Taking into account the combined effect of the density of eggs and the dissolved oxygen concentration, we increase the accuracy of analysis of the experimental results and improve the interpretation of the results. In the conditions of different initial density of eggs, the impact of the concentration of dissolved oxygen on mortality and rates of development of the common toad embryos is manifested in different ways. At high density, only a small percentage of embryos survives by the time of hatching, and the embryos are significantly behind in their development compared with the individuals that developed in normal oxygen conditions. The lack of oxygen dissolved in the water slows down the development of embryos of the common toad.

Modification of a prey catching response and the development of behavioral persistence in the fire-bellied toad (Bombina orientalis).

PubMed

Ramsay, Zachary J; Ikura, Juntaro; Laberge, Frédéric

2013-11-01

The present report investigated how fire-bellied toads (Bombina orientalis) modified their response in a prey catching task in which the attribution of food reward was contingent on snapping toward a visual stimulus of moving prey displayed on a computer screen. Two experiments investigated modification of the snapping response, with different intervals between the opportunity to snap at the visual stimulus and reward administration. The snapping response of unpaired controls was decreased compared with the conditioned toads when hour or day intervals were used, but intervals of 5 min produced only minimal change in snapping. The determinants of extinction of the response toward the visual stimulus were then investigated in 3 experiments. The results of the first experiment suggested that increased resistance to extinction depended mostly on the number of training trials, not on partial reinforcement or the magnitude of reinforcement during training. This was confirmed in a second experiment showing that overtraining resulted in resistance to extinction, and that the pairing of the reward with a response toward the stimulus was necessary for that effect, as opposed to pairing reward solely with the experimental context. The last experiment showed that the time elapsed between training trials also influenced extinction, but only in toads that received few training trials. Overall, the results suggest that toads learning about a prey stimulus progress from an early flexible phase, when an action can be modified by its consequences, to an acquired habit characterized by an increasingly inflexible and automatic response.

Microscopic and immunohistochemical analyses of the claw of the nesting dinosaur, Citipati osmolskae

PubMed Central

Zheng, Wenxia; Schweitzer, Mary H.

2016-01-01

One of the most well-recognized Cretaceous fossils is Citipati osmolskae (MPC-D 100/979), an oviraptorid dinosaur discovered in brooding position on a nest of unhatched eggs. The original description refers to a thin lens of white material extending from a manus ungual, which was proposed to represent original keratinous claw sheath that, in life, would have covered it. Here, we test the hypothesis that this exceptional morphological preservation extends to the molecular level. The fossil sheath was compared with that of extant birds, revealing similar morphology and microstructural organization. In living birds, the claw sheath consists primarily of two structural proteins; alpha-keratin, expressed in all vertebrates, and beta-keratin, found only in reptiles and birds (sauropsids). We employed antibodies raised against avian feathers, which comprise almost entirely of beta-keratin, to demonstrate that fossil tissues respond with the same specificity, though less intensity, as those from living birds. Furthermore, we show that calcium chelation greatly increased antibody reactivity, suggesting a role for calcium in the preservation of this fossil material. PMID:28120795

Microscopic and immunohistochemical analyses of the claw of the nesting dinosaur, Citipati osmolskae.

PubMed

Moyer, Alison E; Zheng, Wenxia; Schweitzer, Mary H

2016-11-16

One of the most well-recognized Cretaceous fossils is Citipati osmolskae (MPC-D 100/979), an oviraptorid dinosaur discovered in brooding position on a nest of unhatched eggs. The original description refers to a thin lens of white material extending from a manus ungual, which was proposed to represent original keratinous claw sheath that, in life, would have covered it. Here, we test the hypothesis that this exceptional morphological preservation extends to the molecular level. The fossil sheath was compared with that of extant birds, revealing similar morphology and microstructural organization. In living birds, the claw sheath consists primarily of two structural proteins; alpha-keratin, expressed in all vertebrates, and beta-keratin, found only in reptiles and birds (sauropsids). We employed antibodies raised against avian feathers, which comprise almost entirely of beta-keratin, to demonstrate that fossil tissues respond with the same specificity, though less intensity, as those from living birds. Furthermore, we show that calcium chelation greatly increased antibody reactivity, suggesting a role for calcium in the preservation of this fossil material. © 2016 The Author(s).

Fine-scale habitat characteristics related to occupancy of the Yosemite Toad, Anaxyrus canorus

Treesearch

Christina T. Liang; Robert L. Grasso; Julie J. Nelson-Paul; Kim E. Vincent; Amy J. Lind

2017-01-01

Fine-scale habitat information can provide insight into species occupancy and persistence that is not apparent at the landscape-scale. Such information is particularly important for rare species that are experiencing population declines, such as the threatened Yosemite Toad (Anaxyrus canorus). Our study examined differences in physical...

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

USGS Publications Warehouse

Liang, Christina T.; Stohlgren, Thomas J.

2011-01-01

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

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

PubMed

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

2011-01-25

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

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

PubMed Central

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

2011-01-01

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

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

PubMed Central

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

2012-01-01

Habitat preservation and management may play an important role in the conservation of the Puerto Rican crested toad, Peltophryne lemur, due to this species' small geographic range and declining native wild population. Bioavailable water concentrations of Polycyclic Aromatic Hydrocarbon (PAH) contaminants within breeding pools at 3 sites were established using Passive Sampling Devices (PSDs) and gas chromatography-mass spectrometry (GC/MS). A more diverse population of PAH analytes were found in higher concentrations at the breeding site that allowed direct vehicular access, but calculated risk quotients indicated low risk to toad reproduction associated with the current PAH analyte levels. PMID:23762634

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

PubMed Central

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

1973-01-01

It is generally believed that urea crosses the cell membrane through aqueous channels, and that its movement across the membrane is accelerated in the direction of net water flow (solvent drag effect). The present report presents evidence for a vasopressin-sensitive pathway for the movement of urea, other amides, and certain non-amides, which is independent of water flow. Phloretin, when present at 10-4 M concentration in the medium bathing the luminal surface of the toad bladder, strongly inhibits the movement of urea, acetamide, and propionamide across the toad bladder, both in the absence and presence of vasopressin. The vasopressin-stimulated movement of formaldehyde and thiourea is also reduced. Osmotic water flow, on the other hand, is not affected; nor is the movement of ethanol and ethylene glycol, or the net transport of sodium. On the basis of these studies we would conclude that the movement of many, if not all, solutes across the cell membrane is independent of water flow, and that a vasopressin-sensitive carrier may be involved in the transport of certain solutes across the cell membrane. PMID:4703229

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

PubMed Central

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

2008-01-01

Alkaloid profiles in skin of poison frogs/toads (Dendrobatidae, Mantellidae, Bufonidae, and Myobatrachidae) are highly dependent on diet and hence on the nature of habitat. Extracts of the two species of toads (Melanophryniscus klappenbachi and M. cupreuscapularis) from similar habitats in the Corrientes/Chaco Provinces of Argentina have similar profiles of alkaloids, which differ considerably from profiles from other Melanophryniscus species from Brazil, Uruguay and Argentina. Structures of two major alkaloids 239Q (1) and 275I (2) were determined by mass, FTIR, and NMR spectral analysis as 5Z,9Z-3-(1-hydroxybutyl)-5-propylindolizidine and 6Z,10E-4,6-di(pent-4-enyl) quinolizidine, respectively. A third alkaloid, 249F (3), is postulated to be a homopumiliotoxin with an unprecedented conjugated exocyclic diene moiety. PMID:18848574

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

USGS Publications Warehouse

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

2011-01-01

The Horned Toad Formation includes five lithostratigraphic members that record alluvial fan, fluvial, lake margin, and lacustrine deposition within a relatively small basin just south of the active Garlock fault during the late Miocene to early Pliocene. These sediments experienced northwest-southeast contractional deformation during the Pliocene-Pleistocene associated with basement-involved reverse faults. Member Two of the Horned Toad Formation has yielded 24 taxa of fossil mammals, referred to as the Warren Local Fauna, including Cryptotis sp., cf. Scapanus, Hypolagus vetus, Hypolagus edensis,? Spermophilus sp., Prothomomys warrenensis n. gen., n. sp., Perognathus sp., Repomys gustelyi, Postcopemys valensis, Peromyscus sp. A, Peromyscus sp. B, Jacobsomys dailyi n. sp., Borophagus cf. B. secundus, cf. Agriotherium, Machairodus sp. cf. M. coloradensis, Rhynchotherium sp. cf. R. edensis, Pliomastodon vexillarius, Dinohippus edensis, Teleoceras sp. cf. T. fossiger, cf. Prosthennops, Megatylopus sp. cf. M. matthewi, Hemiauchenia vera, Camelidae gen. et. sp. indet., and the antilocaprid cf. Sphenophalos. The majority of fossil localities are confined to a 20 m thick stratigraphic interval within a reversed polarity magnetozone. The fauna demonstrates affinity with other late Hemphillian faunas from California, Nevada, Nebraska, Texas, and Mexico. The Lawlor Tuff, dated elsewhere in California at 4.83 ?? 0.04 Ma and geochemically identified in the Horned Toad Formation, overlies most of the fossil mammal localities. Magnetic polarity data are correlated with Chrons 3n.3r, 3n.3n, and 3n.2r, suggesting an age of approximately 5.0 - 4.6 Ma. These constraints indicate an age for the late Hemphillian Warren Local Fauna of 4.85 - 5.0 Ma. ?? Society of Vertebrate Paleontology November 2011.

An Epigenetic Perspective on the Midwife Toad Experiments of Paul Kammerer (1880-1926).

PubMed

Vargas, Alexander O; Krabichler, Quirin; Guerrero-Bosagna, Carlos

2017-01-01

Paul Kammerer was the most outstanding neo-Lamarckian experimentalist of the early 20th century. He reported spectacular results in the midwife toad, including crosses of environmentally modified toads with normal toads, where acquired traits were inherited in Mendelian fashion. Accusations of fraud generated a great scandal, ending with Kammerer's suicide. Controversy reignited in the 1970s, when journalist Arthur Koestler argued against these accusations. Since then, others have argued that Kammerer's results, even if real, were not groundbreaking and could be explained by somatic plasticity, inadvertent selection, or conventional genetics. More recently, epigenetics has uncovered mechanisms by which inheritance can respond directly to environmental change, inviting a reanalysis of Kammerer's descriptions. Previous arguments for mere somatic plasticity have ignored the description of experiments showing heritable germ line modification. Alleged inadvertent selection associated with egg mortality can be discarded, since mortality decreased in a single generation, upon repeated exposures. The challenging implications did not escape the attention of Kammerer's noted contemporary, William Bateson, but he reacted with disbelief, thus encouraging fraud accusations. Nowadays, formerly puzzling phenomena can be explained by epigenetic mechanisms. Importantly, Kammerer described parent-of-origin effects, an effect of parental sex on dominance. Epigenetic mechanisms underlie these effects in genomic imprinting and experiments of transgenerational epigenetic inheritance. In the early 20th century, researchers had no reason to link them with the inheritance of acquired traits. Thus, the parent-of-origin effects in Kammerer's experiments specifically suggest authenticity. Ultimate proof should come from renewed experimentation. To encourage further research, we present a model of possible epigenetic mechanisms. © 2016 Wiley Periodicals, Inc.

HABITAT PATCH OCCUPANCY BY THE TOADS (BUFO PUNCTATUS) IN A NATURALLY FRAGMENTED, DESERT LANDSCAPE

EPA Science Inventory

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

Factors influencing the attitudes of cattle veterinarians, farmers, and claw trimmers towards the pain associated with the treatment of sole ulcers and the sensitivity to pain of dairy cows.

PubMed

Becker, Johanna; Reist, Martin; Steiner, Adrian

2014-04-01

This study assessed the attitudes of personnel involved in therapeutic claw trimming of dairy cattle in Switzerland towards pain associated with sole ulcers and their treatment. Data from 77 farmers, 32 claw trimmers, and 137 cattle veterinarians were used. A large range of factors were associated with whether the respondents thought that anaesthesia during the treatment of sole ulcers was beneficial; these included year of graduation, work experience, attitude to costs of analgesia, perception of competition between veterinarians and claw trimmers, estimation of pain level associated with treatment, estimated sensitivity of dairy cows to pain, knowledge of the obligation to provide analgesia, and whether the respondent thought lesion size and occurrence of defensive behaviour by the cow were important. Respondents' estimation of the pain level associated with sole ulcer treatment was linked to frequency of therapeutic claw trimming, age, farmers' income, estimated knowledge of the benefits of analgesia, and estimated sensitivity of dairy cows to pain. The latter factor was associated with profession, frequency of therapeutic claw trimming, capability of pain recognition, opinion on the benefits of analgesia, knowledge of the obligation to provide analgesia, and self-estimation of the ability to recognise pain. Improving the knowledge of personnel involved in therapeutic claw trimming with regard to pain in dairy cows and how to alleviate it is crucial if management of pain associated with treatment of sole ulcer and the welfare of lame cows are to be optimised. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tubular system volume changes in twitch fibres from toad and rat skeletal muscle assessed by confocal microscopy

PubMed Central

Launikonis, Bradley S; Stephenson, D George

2002-01-01

The volume of the extracellular compartment (tubular system) within intact muscle fibres from cane toad and rat was measured under various conditions using confocal microscopy. Under physiological conditions at rest, the fractional volume of the tubular system (t-sysVol) was 1.38 ± 0.09 % (n = 17), 1.41 ± 0.09 % (n = 12) and 0.83 ± 0.07 % (n = 12) of the total fibre volume in the twitch fibres from toad iliofibularis muscle, rat extensor digitorum longus muscle and rat soleus muscle, respectively. In toad muscle fibres, the t-sysVol decreased by 30 % when the tubular system was fully depolarized and decreased by 15 % when membrane cholesterol was depleted from the tubular system with methyl-β-cyclodextrin but did not change as the sarcomere length was changed from 1.93 to 3.30 μm. There was also an increase by 30 % and a decrease by 25 % in t-sysVol when toad fibres were equilibrated in solutions that were 2.5-fold hypertonic and 50 % hypotonic, respectively. When the changes in total fibre volume were taken into consideration, the t-sysVol expressed as a percentage of the isotonic fibre volume did actually decrease as tonicity increased, revealing that the tubular system in intact fibres cannot be compressed below 0.9 % of the isotonic fibre volume. The results can be explained in terms of forces acting at the level of the tubular wall. These observations have important physiological implications showing that the tubular system is a dynamic membrane structure capable of changing its volume in response to the membrane potential, cholesterol depletion and osmotic stress but not when the sarcomere length is changed in resting muscle. PMID:11790823

Inhibitory effects of devil's claw (secondary root of Harpagophytum procumbens) extract and harpagoside on cytokine production in mouse macrophages.

PubMed

Inaba, Kazunori; Murata, Kazuya; Naruto, Shunsuke; Matsuda, Hideaki

2010-04-01

Successive oral administration (50 mg/kg) of a 50% ethanolic extract (HP-ext) of devil's claw, the secondary root of Harpagophytum procumbens, showed a significant anti-inflammatory effect in the rat adjuvant-induced chronic arthritis model. HP-ext dose-dependently suppressed the lipopolysaccharide (LPS)-induced production of inflammatory cytokines [interleukin-1beta (IL-1beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha)] in mouse macrophage cells (RAW 264.7). Harpagoside, a major iridoid glycoside present in devil's claw, was found to be one of the active agents in HP-ext and inhibited the production of IL-1beta, IL-6, and TNF-alpha by RAW 264.7.

DNA barcode based wildlife forensics for resolving the origin of claw samples using a novel primer cocktail.

PubMed

Khedkar, Gulab D; Abhayankar, Shil Bapurao; Nalage, Dinesh; Ahmed, Shaikh Nadeem; Khedkar, Chandraprakash D

2016-11-01

Excessive wildlife hunting for commercial purposes can have negative impacts on biodiversity and may result in species extinction. To ensure compliance with legal statutes, forensic identification approaches relying on molecular markers may be used to identify the species of origin of animal material from hairs, claw, blood, bone, or meat. Using this approach, DNA sequences from the COI "barcoding" gene have been used to identify material from a number of domesticated animal species. However, many wild species of carnivores still present great challenges in generating COI barcodes using standard "universal" primer pairs. In the work presented here, the mitochondrial COI gene was successfully amplified using a novel primer cocktail, and the products were sequenced to determine the species of twenty one unknown samples of claw material collected as part of forensic wildlife case investigations. Sixteen of the unknown samples were recognized to have originated from either Panthera leo or P. pardus individuals. The remaining five samples could be identified only to the family level due to the absence of reference animal sequences. This is the first report on the use of COI sequences for the identification of P. pardus and P. leo from claw samples as part of forensic investigations in India. The study also highlights the need for adequate reference material to aid in the resolution of suspected cases of illegal wildlife harvesting.

Voltage directive drive with claw pole motor and control without rotor position indicator

NASA Astrophysics Data System (ADS)

Stroenisch, Volker Ewald

Design and testing of a voltage directive drive for synchronous variable speed claw pole motor and control without rotor position indicator is described. Economic analysis of the designed regulation is performed. Computations of stationary and dynamic behavior are given and experimental operational behavior is determined. The motors can be used for electric transportation vehicles, diesel motors, and electric railway engines.

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

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

Smith, G.C.

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

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

PubMed

Garraffo, H Martin; Andriamaharavo, Nirina R; Vaira, Marcos; Quiroga, María F; Heit, Cecilia; Spande, Thomas F

2012-12-01

GC-MS analysis of single-skins of ten Melanophryniscus rubriventris toads (five collections of two toads each) captured during their breeding season in NW Argentina has revealed a total of 127 alkaloids of which 56 had not been previously detected in any frog or toad. Included among these new alkaloids are 23 new diastereomers of previously reported alkaloids. What is particularly distinguishing about the alkaloid profiles of these ten collections is the occurrence of many of the alkaloids, whether known or new to us, in only one of the ten skins sampled, despite two skins being obtained from each breeding site of the five populations. Many of the alkaloids are of classes known to have structures with branched-chains (e.g. pumiliotoxins and tricyclic structures) that are considered to derive from dietary mites. A large number of previously reported and new alkaloids are also of unclassified structures. Only a very few 3,5-disubstituted-indolizidine or -pyrrolizidine alkaloids are observed that have a straight-chain carbon skeleton and are likely derived from ant prey. The possible relationship of these collections made during the toad's brief breeding episodes to sequestration of dietary arthropods and individual alkaloid profiles is discussed.

Design and Implementation of a Brain Computer Interface System for Controlling a Robotic Claw

NASA Astrophysics Data System (ADS)

Angelakis, D.; Zoumis, S.; Asvestas, P.

2017-11-01

The aim of this paper is to present the design and implementation of a brain-computer interface (BCI) system that can control a robotic claw. The system is based on the Emotiv Epoc headset, which provides the capability of simultaneous recording of 14 EEG channels, as well as wireless connectivity by means of the Bluetooth protocol. The system is initially trained to decode what user thinks to properly formatted data. The headset communicates with a personal computer, which runs a dedicated software application, implemented under the Processing integrated development environment. The application acquires the data from the headset and invokes suitable commands to an Arduino Uno board. The board decodes the received commands and produces corresponding signals to a servo motor that controls the position of the robotic claw. The system was tested successfully on a healthy, male subject, aged 28 years. The results are promising, taking into account that no specialized hardware was used. However, tests on a larger number of users is necessary in order to draw solid conclusions regarding the performance of the proposed system.

Anti-inflammatory and antioxidant activities of cat's claw (Uncaria tomentosa and Uncaria guianensis) are independent of their alkaloid content.

PubMed

Sandoval, M; Okuhama, N N; Zhang, X J; Condezo, L A; Lao, J; Angeles', F M; Musah, R A; Bobrowski, P; Miller, M J S

2002-05-01

Cat's claw is an herbal medicine from the Amazon that is used widely to treat inflammatory disorders. The purpose of this study was to characterize the antioxidative and antiinflammatory properties of cat's claw, Uncaria tomentosa (UT) and Uncaria guianensis (UG). Alkaloids and flavanols were determined using reversed-phase HPLC; scavenging of 1,1-diphenyl-2-picrilhydrazyl (DPPH), hydroxyl radicals, and lipid peroxidation by spectrophotometry; and TNFalpha production by ELISA. Anti-inflammatory activity was assessed in vitro by inhibition of TNFalpha and nitrite production from RAW 264.7 cells exposed to LPS (50 ng/ml) and in vivo using the indomethacin-induced gastritis model. Apoptosis was assessed using the TUNEL technique and TNFalpha mRNA by in situ RT-PCR. In each of the antioxidant assays tested, UG was more potent than UT (P < 0.01). The total oxindole and pentacyclic alkaloid content of UT was 35-fold > UG. The IC50 value for inhibition of TNFalpha production was significantly (P < 0.01) higher for UT (14.1 ng/ml) vs UG (9.5 ng/ml), yet at concentrations that were considerable lower than that required for antioxidant activity. Non-alkaloid HPLC fractions from UT decreased LPS-induced TNFalpha and nitrite production in RAW 264.7 cells (P < 0.01) at a concentration range comparable to the parent botanical. Oral pretreatment for 3 d with UT protected against indomethacin-induced gastritis, and prevented TNFalpha mRNA expression and apoptosis. These results indicate that while both species of cat's claw provide effective antioxidant and anti-inflammatory activities, U. guianensis is more potent. In conclusion, the presence of oxindole or pentacyclic alkaloids did not influence the antioxidant and anti-inflammatory properties of cat's claw.

The relation between the effect of a subhypnotic dose of thiopental on claw pain threshold in rats and adrenalin, noradrenalin and dopamine levels.

PubMed

Aksoy, Mehmet; Ahiskalioglu, Ali; Ince, Ilker; Celik, Mine; Dostbil, Aysenur; Kuyrukluyildiz, Ufuk; Altuner, Durdu; Kurt, Nezahat; Suleyman, Halis

2015-01-01

Thiopental sodium (TPS) needs to be applied together with adrenalin in order to establish its analgesic effect in general anesthesia. We aimed to investigate the effect of TPS on the claw pain threshold in rats and evaluated its relationship with endogenous adrenalin (ADR), noradrenalin (NDR), and dopamine (DOP) levels. Intact and adrenalectomized rats were used in the experiment. Intact animals were divided into the following groups: 15 mg/kg TPS (TS), 0.3 mg/kg ADR+15 mg/kg TPS (ATS) and 0.3 mg/kg ADR alone (ADR). Adrenalectomized animals were divided into the following groups: 15 mg/kg TPS (A-TS), 0.3 mg/kg ADR+15 mg/kg TPS (A-ATS) and 0.3 mg/kg ADR alone (A-ADR). Claw pain threshold and blood ADR, NDR, and DOP levels were measured. The TS group's claw pain threshold was found low. However, the claw pain thresholds of the ATS and ADR groups increased significantly. In the A-TS group, the pain threshold decreased compared with normal, and in the A-ATS and A-ADR groups, the pain threshold increased. TPS reduced the blood ADR levels in intact rats; however, no significant changes were observed in the NDR and DOP levels. #TPS provides hyperalgesia by reducing the production of ADR in rats. The present study shows that to achieve analgesic activity, TPS needs to be applied together with ADR.

A new technique using roentgen stereophotogrammetry to measure changes in the spatial conformation of bovine hind claws in response to external loads.

PubMed

Ouweltjes, W; Gussekloo, S W S; Spoor, C W; van Leeuwen, J L

2016-02-01

Claw and locomotion problems are widespread in ungulates. Although it is presumed that mechanical overload is an important contributor to claw tissue damage and impaired locomotion, deformation and claw injury as a result of mechanical loading has been poorly quantified and, as a result, practical solutions to reduce such lesions have been established mostly through trial and error. In this study, an experimental technique was developed that allowed the measurement under controlled loading regimes of minute deformations in the lower limbs of dissected specimens from large ungulates. Roentgen stereophotogrammetric analysis (RSA) was applied to obtain 3D marker coordinates with an accuracy of up to 0.1 mm with optimal contrast and to determine changes in the spatial conformation. A force plate was used to record the applied forces in three dimensions. The results obtained for a test sample (cattle hind leg) under three loading conditions showed that small load-induced deformations and translations as well as small changes in centres of force application could be measured. Accuracy of the order of 0.2-0.3 mm was feasible under practical circumstances with suboptimal contrast. These quantifications of claw deformation during loading improve understanding of the spatial strain distribution as a result of external loading and the risks of tissue overload. The method promises to be useful in determining load-deformation relationships for a wide variety of specimens and circumstances. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Treesearch

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

2010-01-01

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

Inbreeding Ratio and Genetic Relationships among Strains of the Western Clawed Frog, Xenopus tropicalis

PubMed Central

Igawa, Takeshi; Watanabe, Ai; Suzuki, Atsushi; Kashiwagi, Akihiko; Kashiwagi, Keiko; Noble, Anna; Guille, Matt; Simpson, David E.; Horb, Marko E.; Fujii, Tamotsu; Sumida, Masayuki

2015-01-01

The Western clawed frog, Xenopus tropicalis, is a highly promising model amphibian, especially in developmental and physiological research, and as a tool for understanding disease. It was originally found in the West African rainforest belt, and was introduced to the research community in the 1990s. The major strains thus far known include the Nigerian and Ivory Coast strains. However, due to its short history as an experimental animal, the genetic relationship among the various strains has not yet been clarified, and establishment of inbred strains has not yet been achieved. Since 2003 the Institute for Amphibian Biology (IAB), Hiroshima University has maintained stocks of multiple X. tropicalis strains and conducted consecutive breeding as part of the National BioResource Project. In the present study we investigated the inbreeding ratio and genetic relationship of four inbred strains at IAB, as well as stocks from other institutions, using highly polymorphic microsatellite markers and mitochondrial haplotypes. Our results show successive reduction of heterozygosity in the genome of the IAB inbred strains. The Ivory Coast strains clearly differed from the Nigerian strains genetically, and three subgroups were identified within both the Nigerian and Ivory Coast strains. It is noteworthy that the Ivory Coast strains have an evolutionary divergent genetic background. Our results serve as a guide for the most effective use of X. tropicalis strains, and the long-term maintenance of multiple strains will contribute to further research efforts. PMID:26222540

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

USGS Publications Warehouse

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

2006-01-01

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

Multi-component identification and target cell-based screening of potential bioactive compounds in toad venom by UPLC coupled with high-resolution LTQ-Orbitrap MS and high-sensitivity Qtrap MS.

PubMed

Ren, Wei; Han, Lingyu; Luo, Mengyi; Bian, Baolin; Guan, Ming; Yang, Hui; Han, Chao; Li, Na; Li, Tuo; Li, Shilei; Zhang, Yangyang; Zhao, Zhenwen; Zhao, Haiyu

2018-04-28

Traditional Chinese medicines (TCMs) are undoubtedly treasured natural resources for discovering effective medicines in treating and preventing various diseases. However, it is still extremely difficult for screening the bioactive compounds due to the tremendous constituents in TCMs. In this work, the chemical composition of toad venom was comprehensively analyzed using ultra-high performance liquid chromatography (UPLC) coupled with high-resolution LTQ-Orbitrap mass spectrometry and 93 compounds were detected. Among them, 17 constituents were confirmed by standard substances and 8 constituents were detected in toad venom for the first time. Further, a compound database of toad venom containing the fullest compounds was further constructed using UPLC coupled with high-sensitivity Qtrap MS. Then a target cell-based approach for screening potential bioactive compounds from toad venom was developed by analyzing the target cell extracts. The reliability of this method was validated by negative controls and positive controls. In total, 17 components in toad venom were discovered to interact with the target cancer cells. Further, in vitro pharmacological trials were performed to confirm the anti-cancer activity of four of them. The results showed that the six bufogenins and seven bufotoxins detected in our research represented a promising resource to explore bufogenins/bufotoxins-based anticancer agents with low cardiotoxic effect. The target cell-based screening method coupled with the compound database of toad venom constructed by UPLC-Qtrap-MS with high sensitivity provide us a new strategy to rapidly screen and identify the potential bioactive constituents with low content in natural products, which was beneficial for drug discovery from other TCMs. ᅟ Graphical abstract.

Effects of internal and external pH on amiloride-blockable Na transport across toad urinary bladder vesicles

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

Garty, H.; Civan, E.D.; Civan, M.M.

1985-01-01

The authors have examined the effect of internal and external pH on Na+ transport across toad bladder membrane vesicles. Of the total SSNa uptake measured 0.5-2.0 min after introducing tracer, 80 +/- 4% (mean +/- SE, n = 9) is blocked by the diuretic with a KI of 2 X 10(-8) M. Thus, this amiloride-sensitive flux is mediated by the apical sodium-selective channels. Varying the internal (cytosolic) pH over the physiologic range 7.0-8.0 had no effect on sodium transport; this result suggests that variation of intracellular pH in vivo has no direct apical effect on modulating sodium uptake. On themore » other hand, SSNa was directly and monotonically dependent on external pH. External acidification also reduced the amiloride-sensitive efflux across the walls of the vesicles. This inhibition of 22Na efflux was noted at external Na concentrations of both 0.2 microM and 53 mM. These results are different from those reported with whole toad bladder. A number of possible bases for these differences are considered and discussed. They suggest that the natriferic response induced by mucosal acidification of whole toad urinary bladder appears to operate indirectly through one or more factors, presumably cytosolic, present in whole cells and absent from the vesicles.« less

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

PubMed

Samanta, Luna; Paital, Biswaranjan

2016-11-01

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

Preparation and use of Xenopus egg extracts to study DNA replication and chromatin associated proteins

PubMed Central

Gillespie, Peter J.; Gambus, Agnieszka; Blow, J. Julian

2012-01-01

The use of cell-free extracts prepared from eggs of the South African clawed toad, Xenopus laevis, has led to many important discoveries in cell cycle research. These egg extracts recapitulate the key nuclear transitions of the eukaryotic cell cycle in vitro under apparently the same controls that exist in vivo. DNA added to the extract is first assembled into a nucleus and is then efficiently replicated. Progression of the extract into mitosis then allows the separation of paired sister chromatids. The Xenopus cell-free system is therefore uniquely suited to the study of the mechanisms, dynamics and integration of cell cycle regulated processes at a biochemical level. In this article we describe methods currently in use in our laboratory for the preparation of Xenopus egg extracts and demembranated sperm nuclei for the study of DNA replication in vitro. We also detail how DNA replication can be quantified in this system. In addition, we describe methods for isolating chromatin and chromatin-bound protein complexes from egg extracts. These recently developed and revised techniques provide a practical starting point for investigating the function of proteins involved in DNA replication. PMID:22521908

The relation between the effect of a subhypnotic dose of thiopental on claw pain threshold in rats and adrenalin, noradrenalin and dopamine levels

PubMed Central

Aksoy, Mehmet; Ahiskalioglu, Ali; Ince, Ilker; Celik, Mine; Dostbil, Aysenur; Kuyrukluyildiz, Ufuk; Altuner, Durdu; Kurt, Nezahat; Suleyman, Halis

2015-01-01

Thiopental sodium (TPS) needs to be applied together with adrenalin in order to establish its analgesic effect in general anesthesia. We aimed to investigate the effect of TPS on the claw pain threshold in rats and evaluated its relationship with endogenous adrenalin (ADR), noradrenalin (NDR), and dopamine (DOP) levels. Intact and adrenalectomized rats were used in the experiment. Intact animals were divided into the following groups: 15 mg/kg TPS (TS), 0.3 mg/kg ADR+15 mg/kg TPS (ATS) and 0.3 mg/kg ADR alone (ADR). Adrenalectomized animals were divided into the following groups: 15 mg/kg TPS (A-TS), 0.3 mg/kg ADR+15 mg/kg TPS (A-ATS) and 0.3 mg/kg ADR alone (A-ADR). Claw pain threshold and blood ADR, NDR, and DOP levels were measured. The TS group’s claw pain threshold was found low. However, the claw pain thresholds of the ATS and ADR groups increased significantly. In the A-TS group, the pain threshold decreased compared with normal, and in the A-ATS and A-ADR groups, the pain threshold increased. TPS reduced the blood ADR levels in intact rats; however, no significant changes were observed in the NDR and DOP levels. #TPS provides hyperalgesia by reducing the production of ADR in rats. The present study shows that to achieve analgesic activity, TPS needs to be applied together with ADR. PMID:26211784

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

EPA Science Inventory

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

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

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

The influence of the environment on dairy cow behavior, claw health and herd lameness dynamics.

PubMed

Cook, Nigel B; Nordlund, Kenneth V

2009-03-01

Free stall housing increases the exposure of dairy cows' claws to concrete walk-ways and to manure between periods of rest, and generally shows the highest rate of lameness compared with other dairy management systems. However, there is great variation within a system, and the rate of new cases of lameness can be reduced to very low levels provided time spent resting per day is maximized through good stall design, access to stalls through stocking density control and comfortable transition cow facilities, limiting the time spent milking, provision of adequate heat abatement, and good leg hygiene. Sand bedded stalls are useful as they also permit lame cows to maintain adequate daily rest. Rubberized alley flooring surfaces benefit the cow by reducing claw wear and trauma compared to concrete, making them ideal for parlor holding areas and long transfer lanes and walk ways. However, caution is required when using rubber floors in pens with uncomfortable stalls due to apparent adverse effects on cow time budgets, which may in turn have a detrimental effect on lameness.

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

PubMed

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

2013-01-01

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

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

Treesearch

Evelyn L Bull; Jane L. Hayes

2009-01-01

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

ELECTRON MICROSCOPY OF ABSORPTION OF TRACER MATERIALS BY TOAD URINARY BLADDER EPITHELIUM

PubMed Central

Choi, Jae Kwon

1965-01-01

The absorption of Thorotrast and saccharated iron oxide by the epithelium of the toad urinary bladder was studied by electron microscopy. Whether the toads were hydrated, dehydrated, or given Pitressin, no significant differences in transport of colloidal particles by epithelial cells were observed. This implies that these physiological factors had little effect on the transport of the tracer particles. Tracer particles were encountered in three types of epithelial cells which line the bladder lumen, but most frequently in the mitochondria-rich cells. Tracer materials were incorporated into the cytoplasm of epithelial cells after being adsorbed to the coating layer covering the luminal surface of the cells. In the intermediate stage (1 to 3 hours after introducing tracer) particles were present in small vesicles, tubules, and multivesicular bodies. In the later stages (up to 65 hours), the particles were more commonly seen to be densely packed within large membrane-bounded bodies which were often found near the Golgi region. These large bodies probably were formed by the fusion of small vesicles. Irrespective of the stages of absorption, no particles were found in the intercellular spaces or in the submucosa. Particles apparently did not penetrate the intercellular spaces of the epithelium beyond the level of the tight junction. PMID:14287173

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

EPA Science Inventory

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

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

PubMed

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

2007-12-01

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

No evidence for effects of infection with the amphibian chytrid fungus on populations of yellow-bellied toads.

PubMed

Wagner, Norman; Neubeck, Claus; Guicking, Daniela; Finke, Lennart; Wittich, Martin; Weising, Kurt; Geske, Christian; Veith, Michael

2017-02-08

The parasitic chytrid fungus Batrachochytrium dendrobatidis (Bd) can cause the lethal disease chytridiomycosis in amphibians and therefore may play a role in population declines. The yellow-bellied toad Bombina variegata suffered strong declines throughout western and northwestern parts of its range and is therefore listed as highly endangered for Germany and the federal state of Hesse. Whether chytridiomycosis may play a role in the observed local declines of this strictly protected anuran species has never been tested. We investigated 19 Hessian yellow-bellied toad populations for Bd infection rates, conducted capture-mark-recapture studies in 4 of them over 2 to 3 yr, examined survival histories of recaptured infected individuals, and tested whether multi-locus heterozygosity of individuals as well as expected heterozygosity and different environmental variables of populations affect probabilities of Bd infection. Our results show high prevalence of Bd infection in Hessian yellow-bellied toad populations, but although significant decreases in 2 populations could be observed, no causative link to Bd as the reason for this can be established. Mass mortalities or obvious signs of disease in individuals were not observed. Conversely, we show that growth of Bd-infected populations is possible under favorable habitat conditions and that most infected individuals could be recaptured with improved body indices. Neither genetic diversity nor environmental variables appeared to affect Bd infection probabilities. Hence, genetically diverse amphibian specimens and populations may not automatically be less susceptible for Bd infection.

Granulocytes of the red claw crayfish Cherax quadricarinatus can endocytose beads, E. coli and WSSV, but in different ways.

PubMed

Duan, Hu; Jin, Songjun; Zhang, Yan; Li, Fuhua; Xiang, Jianhai

2014-10-01

The hemocytes of the red claw crayfish Cherax quadricarinatus are classified by morphologic observation into the following types: hyalinocytes (H), semi-granulocytes (SG) and granulocytes (G). Density gradient centrifugation with Percoll was developed to separate these three subpopulations of hemocytes. Beads, Escherichia coli, and FITC labeling WSSV were used to investigate the characteristics of granulocytes by using scanning electron microscope, transmission electron microscope, and laser scan confocal microscope. Results showed that granulocytes could phagocytose beads and E. coli by endocytic pathways. WSSV could rely on caveolae-mediated endocytosis to mainly enter into granulocytes. These results could elucidate the mechanism of the innate immunity function of granulocytes, and it also showed the mechanism by which WSSV invaded granulocytes in the red claw crayfish. Copyright © 2014 Elsevier Ltd. All rights reserved.

Polyphyly of Asian Tree Toads, Genus Pedostibes Günther, 1876 (Anura: Bufonidae), and the Description of a New Genus from Southeast Asia

PubMed Central

Grismer, L. Lee; Zachariah, Anil; Brown, Rafe M.

2016-01-01

The Asian Tree Toad genus Pedostibes, as currently understood, exhibits a conspicuously disjunct distribution, posing several immediate questions relating to the biogeography and taxonomy of this poorly known group. The type species, P. tuberculosus and P. kempi, are known only from India, whereas P. hosii, P. rugosus, and P. everetti are restricted to Southeast Asia. Several studies have shown that these allopatric groups are polyphyletic, with the Indian Pedostibes embedded within a primarily South Asian clade of toads, containing the genera Adenomus, Xanthophryne, and Duttaphrynus. Southeast Asian Pedostibes on the other hand, are nested within a Southeast Asian clade, which is the sister lineage to the Southeast Asian river toad genus Phrynoidis. We demonstrate that Indian and Southeast Asian Pedostibes are not only allopatric and polyphyletic, but also exhibit significant differences in morphology and reproductive mode, indicating that the Southeast Asian species’ are not congeneric with the true Pedostibes of India. As a taxonomic solution, we describe a new genus, Rentapia gen. nov. to accommodate the Southeast Asian species. PMID:26788854

Telencephalic Neuronal Activation Associated with Spatial Memory in the Terrestrial Toad Rhinella arenarum: Participation of the Medial Pallium during Navigation by Geometry.

PubMed

Sotelo, María Inés; Daneri, M Florencia; Bingman, Verner Peter; Muzio, Rubén N

2016-01-01

Amphibians are central to discussions of vertebrate evolution because they represent the transition from aquatic to terrestrial life, a transition with profound consequences for the selective pressures shaping brain evolution. Spatial navigation is one class of behavior that has attracted the interest of comparative neurobiologists because of the relevance of the medial pallium/hippocampus, yet, surprisingly, in this regard amphibians have been sparsely investigated. In the current study, we trained toads to locate a water goal relying on the boundary geometry of a test environment (Geometry-Only) or boundary geometry coupled with a prominent, visual feature cue (Geometry-Feature). Once learning had been achieved, the animals were given one last training session and their telencephali were processed for c-Fos activation. Compared to control toads exposed to the test environment for the first time, geometry-only toads were found to have increased neuronal labeling in the medial pallium, the presumptive hippocampal homologue, while geometry-feature toads were found to have increased neuronal labeling in the medial, dorsal, and lateral pallia. The data indicate medial pallial participation in guiding navigation by environmental geometry and lateral, and to a lesser extent dorsal, pallial participation in guiding navigation by a prominent visual feature. As such, participation of the medial pallium/hippocampus in spatial cognition appears to be a conserved feature of terrestrial vertebrates even if their life history is still tied to water, a brain-behavior feature seemingly at least as ancient as the evolutionary transition to life on land. © 2016 S. Karger AG, Basel.

Effect of claw disorders on milk production, fertility, and longevity, and their economic impact in Spanish Holstein cows.

PubMed

Charfeddine, N; Pérez-Cabal, M A

2017-01-01

The aims of this study were (1) to estimate the phenotypic association between different degrees of severity of claw disorders and production, fertility performance, and longevity in Spanish dairy cattle, and (2) to quantify its economic impact at the animal and herd level. In this study, claw data comprised 108,468 trimmings collected between 2012 and 2014 by 25 trimmers from 804 Holstein dairy herds. The claw disorders considered were the 3 most frequent disorders in Spanish dairy herds: dermatitis (DE), sole ulcer (SU), and white line disease (WL). The presence of SU or WL was associated with a significant decrease in milk production and was more important in cows in second or later lactations. A severe lesion of SU or WL lead to twice the milk losses associated with a mild lesion, ranging from 1.47 to 2.66kg/d of energy-corrected milk. The presence of SU or WL during the early lactation period was associated with more days open, fewer inseminations to get pregnant, and longer calving to first service interval (4.83 and 8.0 d longer due to mild and severe lesions of SU, respectively, and 4.94 and 17.43 d longer due to mild and severe lesions of WL, respectively). The occurrence of a case of SU or WL in first lactation had a significant effect on longevity, with severe lesions reducing up to 71 d of productive life. The cost of a mild lesion ranged from $53 to $232 per affected cow and year, whereas the cost of a severe lesion ranged from $402 to $622 per affected cow and year. The annual costs per cow for DE, SU, and WL were $10.80, $50.9, and $43.2, respectively. An average herd with 64 cows had an extra expenditure of $691/yr due to DE, $3,256/yr due to SU, and $2,765/year due to WL. Milk losses, longer calving intervals, and premature culling contributed to more than half of the costs. Therefore, providing this information to farmers could help decide on strategies to reduce the incidence of claw disorders on the farm. Copyright © 2017 American Dairy Science

Regulation of Phosphorylation of a Specific Protein in Toad-Bladder Membrane by Antidiuretic Hormone and Cyclic AMP, and Its Possible Relationship to Membrane Permeability Changes

PubMed Central

DeLorenzo, Robert J.; Walton, Kenneth G.; Curran, Peter F.; Greengard, Paul

1973-01-01

Phosphorylation of a specific protein was decreased in intact toad bladders by exposure to either antidiuretic hormone or monobutyryl cyclic AMP. The decrease in phosphorylation caused by these agents preceded the change in electrical potential difference (an indicator of the rate of sodium ion transport) observed in response to the same compounds. The addition of cyclic AMP to homogenates of toad bladder led to a decrease in phosphorylation of the same, or a similar, protein. In subcellular fractionation studies, the effect of cyclic AMP on the phosphorylation of this protein was observed in those fractions rich in membrane fragments, but not in the nuclear or cell-sap fractions. These and other results are compatible with the possibility that the regulation by vasopressin and cyclic AMP of sodium and/or water transport in toad bladder may be mediated through regulation of the phosphorylation of this specific protein. Images PMID:4351809

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

EPA Science Inventory

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

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

EPA Science Inventory

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

10Gbit/s all-optical NRZ to RZ conversion based on TOAD

NASA Astrophysics Data System (ADS)

Yan, Yumei; Yin, Lina; Zhou, Yunfeng; Liu, Guoming; Wu, Jian; Lin, Jintong

2006-01-01

Future network will include wavelength division multiplexing (WDM) and optical time division multiplexing (OTDM) technologies. All-optical format conversion between their respective preferable data formats, non-return-to-zero (NRZ) and return-to-zero (RZ), may become an important technology. In this paper, 10Gbit/s all-optical NRZ-to-RZ conversion is demonstrated based on terahertz optical asymmetric demultiplexer (TOAD) using clock all-optically recovered from the NRZ signal for the first time. The clock component is enhanced in an SOA and the pseudo-return-to-zero (PRZ) signal is filtered. The PRZ signal is input into an injection mode-locked fiber ring laser for clock recovery. The recovered clock and the NRZ signal are input into TOAD as pump signal and probe signal, respectively, and format conversion is performed. The quality of the converted RZ signal is determined by that of the recovered clock and the NRZ signal, whereas hardly influenced by gain recovery time of the SOA. In the experimental demonstration, the obtained RZ signal has an extinction ratio of 8.7dB and low pattern dependency. After conversion, the spectrum broadens obviously and shows multimode structure with spectrum interval of 0.08nm, which matches with the bit rate 10Gbit/s. Furthermore, this format conversion method has some tolerance on the pattern dependency of the clock signal.

The complex evolutionary history of the tympanic middle ear in frogs and toads (Anura)

PubMed Central

Pereyra, Martín O.; Womack, Molly C.; Barrionuevo, J. Sebastián; Blotto, Boris L.; Baldo, Diego; Targino, Mariane; Ospina-Sarria, Jhon Jairo; Guayasamin, Juan M.; Coloma, Luis A.; Hoke, Kim L.; Grant, Taran; Faivovich, Julián

2016-01-01

Most anurans possess a tympanic middle ear (TME) that transmits sound waves to the inner ear; however, numerous species lack some or all TME components. To understand the evolution of these structures, we undertook a comprehensive assessment of their occurrence across anurans and performed ancestral character state reconstructions. Our analysis indicates that the TME was completely lost at least 38 independent times in Anura. The inferred evolutionary history of the TME is exceptionally complex in true toads (Bufonidae), where it was lost in the most recent common ancestor, preceding a radiation of >150 earless species. Following that initial loss, independent regains of some or all TME structures were inferred within two minor clades and in a radiation of >400 species. The reappearance of the TME in the latter clade was followed by at least 10 losses of the entire TME. The many losses and gains of the TME in anurans is unparalleled among tetrapods. Our results show that anurans, and especially bufonid toads, are an excellent model to study the behavioural correlates of earlessness, extratympanic sound pathways, and the genetic and developmental mechanisms that underlie the morphogenesis of TME structures. PMID:27677839

The complex evolutionary history of the tympanic middle ear in frogs and toads (Anura).

PubMed

Pereyra, Martín O; Womack, Molly C; Barrionuevo, J Sebastián; Blotto, Boris L; Baldo, Diego; Targino, Mariane; Ospina-Sarria, Jhon Jairo; Guayasamin, Juan M; Coloma, Luis A; Hoke, Kim L; Grant, Taran; Faivovich, Julián

2016-09-28

Most anurans possess a tympanic middle ear (TME) that transmits sound waves to the inner ear; however, numerous species lack some or all TME components. To understand the evolution of these structures, we undertook a comprehensive assessment of their occurrence across anurans and performed ancestral character state reconstructions. Our analysis indicates that the TME was completely lost at least 38 independent times in Anura. The inferred evolutionary history of the TME is exceptionally complex in true toads (Bufonidae), where it was lost in the most recent common ancestor, preceding a radiation of >150 earless species. Following that initial loss, independent regains of some or all TME structures were inferred within two minor clades and in a radiation of >400 species. The reappearance of the TME in the latter clade was followed by at least 10 losses of the entire TME. The many losses and gains of the TME in anurans is unparalleled among tetrapods. Our results show that anurans, and especially bufonid toads, are an excellent model to study the behavioural correlates of earlessness, extratympanic sound pathways, and the genetic and developmental mechanisms that underlie the morphogenesis of TME structures.

Metabolomics method based on ultra high performance liquid chromatography with time-of-flight mass spectrometry to analyze toxins in fresh and dried toad venom.

PubMed

Ma, Hongyue; Niu, Huixia; Cao, Qin; Zhou, Jing; Gong, Yan; Zhu, Zhenhua; Lv, Xiang; Di, Liuqing; Qian, Dawei; Wu, Qinan; Duan, Jin'ao

2016-12-01

Drying is a critical step to prolong the storage time in natural medicine processing but it changes the chemical characteristics of the product. In this study, research was performed to characterize the metabolomic changes in toad venom induced by vacuum-drying at 60°C and air-drying at room temperature by ultra high performance liquid chromatography coupled with pattern recognition approaches. In total 52 metabolites, down-regulated or up-regulated, were identified as potential chemical markers. Compared with fresh toad venom, vacuum-drying at 60°C succeeded in raising the conjugated-type bufadienolide content significantly, while the content of free-type bufadienolides were slightly reduced. On the other hand, toad venom air-dried at room temperature presented a relatively low amount of bufadienolides compared with fresh venom. For example, the content of several known anti-tumor components (gamabufotalin, bufotalin, cinobufagin, etc.) were significantly reduced. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide bioassay further showed that venom air-dried at room temperature had weaker anti-tumor activity on human hepatocellular carcinoma SMMC-7721 proliferation in vitro than samples vacuum-dried at 60°C. These results showed that the great metabolomic changes of toad venom occurred during the drying process, suggesting that a proper drying procedure is important for sustaining the chemical quality of natural medicines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Terrestrial reproduction as an adaptation to steep terrain in African toads

PubMed Central

Müller, Hendrik; Hafner, Julian; Penner, Johannes; Mazuch, Tomáš; Rödel, Mark-Oliver; Loader, Simon P.

2017-01-01

How evolutionary novelties evolve is a major question in evolutionary biology. It is widely accepted that changes in environmental conditions shift the position of selective optima, and advancements in phylogenetic comparative approaches allow the rigorous testing of such correlated transitions. A longstanding question in vertebrate biology has been the evolution of terrestrial life histories in amphibians and here, by investigating African bufonids, we test whether terrestrial modes of reproduction have evolved as adaptations to particular abiotic habitat parameters. We reconstruct and date the most complete species-level molecular phylogeny and estimate ancestral states for reproductive modes. By correlating continuous habitat measurements from remote sensing data and locality records with life-history transitions, we discover that terrestrial modes of reproduction, including viviparity evolved multiple times in this group, most often directly from fully aquatic modes. Terrestrial modes of reproduction are strongly correlated with steep terrain and low availability of accumulated water sources. Evolutionary transitions to terrestrial modes of reproduction occurred synchronously with or after transitions in habitat, and we, therefore, interpret terrestrial breeding as an adaptation to these abiotic conditions, rather than an exaptation that facilitated the colonization of montane habitats. PMID:28356450

Terrestrial reproduction as an adaptation to steep terrain in African toads.

PubMed

Liedtke, H Christoph; Müller, Hendrik; Hafner, Julian; Penner, Johannes; Gower, David J; Mazuch, Tomáš; Rödel, Mark-Oliver; Loader, Simon P

2017-03-29

How evolutionary novelties evolve is a major question in evolutionary biology. It is widely accepted that changes in environmental conditions shift the position of selective optima, and advancements in phylogenetic comparative approaches allow the rigorous testing of such correlated transitions. A longstanding question in vertebrate biology has been the evolution of terrestrial life histories in amphibians and here, by investigating African bufonids, we test whether terrestrial modes of reproduction have evolved as adaptations to particular abiotic habitat parameters. We reconstruct and date the most complete species-level molecular phylogeny and estimate ancestral states for reproductive modes. By correlating continuous habitat measurements from remote sensing data and locality records with life-history transitions, we discover that terrestrial modes of reproduction, including viviparity evolved multiple times in this group, most often directly from fully aquatic modes. Terrestrial modes of reproduction are strongly correlated with steep terrain and low availability of accumulated water sources. Evolutionary transitions to terrestrial modes of reproduction occurred synchronously with or after transitions in habitat, and we, therefore, interpret terrestrial breeding as an adaptation to these abiotic conditions, rather than an exaptation that facilitated the colonization of montane habitats. © 2017 The Author(s).

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

PubMed

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

2018-05-02

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

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

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

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

1987-03-01

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

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

Treesearch

Christina T. Liang

2013-01-01

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

Telencephalic neural activation following passive avoidance learning in a terrestrial toad.

PubMed

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

2016-12-15

The present study explores passive avoidance learning and its neural basis in toads (Rhinella arenarum). In Experiment 1, two groups of toads learned to move from a lighted compartment into a dark compartment. After responding, animals in the experimental condition were exposed to an 800-mM strongly hypertonic NaCl solution that leads to weight loss. Control animals received exposure to a 300-mM slightly hypertonic NaCl solution that leads to neither weight gain nor loss. After 10 daily acquisition trials, animals in the experimental group showed significantly longer latency to enter the dark compartment. Additionally, 10 daily trials in which both groups received the 300-mM NaCl solution after responding eliminated this group effect. Thus, experimental animals showed gradual acquisition and extinction of a passive avoidance respond. Experiment 2 replicated the gradual acquisition effect, but, after the last trial, animals were sacrificed and neural activation was assessed in five brain regions using AgNOR staining for nucleoli-an index of brain activity. Higher activation in the experimental animals, relative to controls, was observed in the amygdala and striatum. Group differences in two other regions, lateral pallium and septum, were borderline, but nonsignificant, whereas group differences in the medial pallium were nonsignificant. These preliminary results suggest that a striatal-amygdala activation could be a key component of the brain circuit controlling passive avoidance learning in amphibians. The results are discussed in relation to the results of analogous experiments with other vertebrates. Copyright © 2016 Elsevier B.V. All rights reserved.

The effect of supplementation with vitamin A on serum and liver concentrations in Puerto Rican crested toads (Peltophryne lemur) and its lack of impact on brown skin disease.

PubMed

Dutton, Christopher; Lentini, Andrew; Berkvens, Charlene; Crawshaw, Graham

2014-01-01

"Brown skin disease" (BSD) is a clinical syndrome of dysecdysis, chronic weight loss and death, previously reported in Puerto Rican crested toads (Peltophryne lemur). Although vitamin A deficiency has been suggested, its cause remains unknown and multiple treatments have failed to prevent or reverse the condition. This study compared the efficacy of vitamin A supplementation, administered in different forms and by different routes, in 48 captive born Puerto Rican crested toads fed from metamorphosis on gut-loaded, dusted, commercially raised crickets. Forty-five toads started to show clinical signs of BSD at 9 months of age; all toads were treated orally with an oil-based vitamin A formulation twice weekly for 2 months but continued to deteriorate. Two treatment groups were then compared: Animals in one group (n=19) received 2 IU injectable vitamin A (Aquasol-A) per gram bodyweight subcutaneously twice weekly for 3 months with no change in diet. Toads in the other group (n=22) received a single oral dose of vitamins A, D3 , and E, and were fed on earthworms and crickets gut-loaded with produce and a finely-ground alfalfa-based pellet, dusted with the same vitamin/mineral supplement. All affected animals developed severe BSD equally and died during, or were euthanized at the end of, the treatment regimen, with no clinical improvement. Animals supplemented with Aquasol-A had significantly higher liver vitamin A concentrations compared with the other treatment group, whereas serum retinol concentrations showed no significant difference. Vitamin A supplementation does not appear a successful treatment once BSD symptoms have developed. © 2014 Wiley Periodicals, Inc.

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

EPA Science Inventory

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

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

EPA Science Inventory

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

Biomarker analysis of American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles following exposure to atrazine.

EPA Science Inventory

The objective of the current study was to use a biomarker-based approach to investigate the influence of atrazine exposure on American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles. Atrazine is one of the most frequently detected herbicides in environme...

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

EPA Science Inventory

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

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

PubMed

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

1998-12-01

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

The effects of dietary biotin supplementation on vertical fissures of the claw wall in beef cattle.

PubMed Central

Campbell, J R; Greenough, P R; Petrie, L

2000-01-01

A clinical field trial was performed on a herd of Hereford beef cows in central Saskatchewan. The herd had a history of being severely affected with vertical fissures. The objective of the study was to determine the effects of supplemental dietary biotin on the prevalence of vertical fissures in beef cows. In June 1994 and June 1995, 1- and 2-year-old heifers were randomly allocated into 2 treatment groups, each composed of 79 animals. One group received a 10 mg/head/day biotin-supplemented free-choice mineral supplement, while the other groups received an identical free-choice mineral without the biotin supplementation. The claws from these animals were evaluated in June 1994, October 1994, June 1995, October 1995, and June 1996 for the presence of vertical fissures. Supplemental dietary biotin significantly increased serum levels of biotin and significantly increased claw hardness in supplemented cows. Both groups of heifers started the trial without vertical fissures. After 18 months, 15% of the cows fed supplemental dietary biotin had vertical fissures compared with 33% in the nonsupplemented group. The difference was statistically significant (P = 0.01). PMID:10992986

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

PubMed

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

2006-05-01

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

Rod phototransduction determines the trade-off of temporal integration and speed of vision in dark-adapted toads.

PubMed

Haldin, Charlotte; Nymark, Soile; Aho, Ann-Christine; Koskelainen, Ari; Donner, Kristian

2009-05-06

Human vision is approximately 10 times less sensitive than toad vision on a cool night. Here, we investigate (1) how far differences in the capacity for temporal integration underlie such differences in sensitivity and (2) whether the response kinetics of the rod photoreceptors can explain temporal integration at the behavioral level. The toad was studied as a model that allows experimentation at different body temperatures. Sensitivity, integration time, and temporal accuracy of vision were measured psychophysically by recording snapping at worm dummies moving at different velocities. Rod photoresponses were studied by ERG recording across the isolated retina. In both types of experiments, the general timescale of vision was varied by using two temperatures, 15 and 25 degrees C. Behavioral integration times were 4.3 s at 15 degrees C and 0.9 s at 25 degrees C, and rod integration times were 4.2-4.3 s at 15 degrees C and 1.0-1.3 s at 25 degrees C. Maximal behavioral sensitivity was fivefold lower at 25 degrees C than at 15 degrees C, which can be accounted for by inability of the "warm" toads to integrate light over longer times than the rods. However, the long integration time at 15 degrees C, allowing high sensitivity, degraded the accuracy of snapping toward quickly moving worms. We conclude that temporal integration explains a considerable part of all variation in absolute visual sensitivity. The strong correlation between rods and behavior suggests that the integration time of dark-adapted vision is set by rod phototransduction at the input to the visual system. This implies that there is an inexorable trade-off between temporal integration and resolution.

Genetic diversity of Morato's Digger Toad, Proceratophrys moratoi: spatial structure, gene flow, effective size and the need for differential management strategies of populations

PubMed Central

Arruda, Mauricio P.; Costa, William P.; Recco-Pimentel, Shirlei M.

2017-01-01

Abstract The Morato's Digger Toad, Proceratophrys moratoi, is a critically endangered toad species with a marked population decline in southern Brazilian Cerrado. Despite this, new populations are being discovered, primarily in the northern part of the distribution range, which raises a number of questions with regard to the conservation status of the species. The present study analyzed the genetic diversity of the species based on microsatellite markers. Our findings permitted the identification of two distinct management units. We found profound genetic structuring between the southern populations, on the left margin of the Tietê River, and all other populations. A marked reduction was observed in the contemporary gene flow among the central populations that are most affected by anthropogenic impacts, such as extensive sugar cane plantations, which presumably decreases habitat connectivity. The results indicated reduced diversity in the southern populations which, combined with a smaller effective population size, may make these populations more susceptible to extinction. We recommend the reclassification of P. moratoi as vulnerable and the establishment of a special protection program for the southern populations. Our results provide important insights about the local extinction of southern populations of this toad. PMID:28590500

Genetic diversity of Morato's Digger Toad, Proceratophrys moratoi: spatial structure, gene flow, effective size and the need for differential management strategies of populations.

PubMed

Arruda, Mauricio P; Costa, William P; Recco-Pimentel, Shirlei M

2017-01-01

The Morato's Digger Toad, Proceratophrys moratoi, is a critically endangered toad species with a marked population decline in southern Brazilian Cerrado. Despite this, new populations are being discovered, primarily in the northern part of the distribution range, which raises a number of questions with regard to the conservation status of the species. The present study analyzed the genetic diversity of the species based on microsatellite markers. Our findings permitted the identification of two distinct management units. We found profound genetic structuring between the southern populations, on the left margin of the Tietê River, and all other populations. A marked reduction was observed in the contemporary gene flow among the central populations that are most affected by anthropogenic impacts, such as extensive sugar cane plantations, which presumably decreases habitat connectivity. The results indicated reduced diversity in the southern populations which, combined with a smaller effective population size, may make these populations more susceptible to extinction. We recommend the reclassification of P. moratoi as vulnerable and the establishment of a special protection program for the southern populations. Our results provide important insights about the local extinction of southern populations of this toad.

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

PubMed

Petrovan, Silviu O; Schmidt, Benedikt R

2016-01-01

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

Influence of demography and environment on persistence in toad populations

USGS Publications Warehouse

Lambert, Brad A.; Schorr, Robert A.; Schneider, Scott C.; Muths, Erin L.

2016-01-01

Effective conservation of rare species requires an understanding of how potential threats affect population dynamics. Unfortunately, information about population demographics prior to threats (i.e., baseline data) is lacking for many species. Perturbations, caused by climate change, disease, or other stressors can lead to population declines and heightened conservation concerns. Boreal toads (Anaxyrus boreas boreas) have undergone rangewide declines due mostly to the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd), with only a few sizable populations remaining in the southern Rocky Mountains, USA, that are disease-free. Despite the apparent region-wide occurrence of Bd, our focal populations in central Colorado were disease free over a 14-year capture-mark-recapture study until the recent discovery of Bd at one of the sites. We used recapture data and the Pradel reverse-time model to assess the influence of environmental and site-specific conditions on survival and recruitment. We then forecast changes in the toad populations with 2 growth models; one using an average lambda value to initiate the projection, and one using the most recent value to capture potential effects of the incursion of disease into the system. Adult survival was consistently high at the 3 sites, whereas recruitment was more variable and markedly low at 1 site. We found that active season moisture, active season length, and breeding shallows were important factors in estimating recruitment. Population growth models indicated a slight increase at 1 site but decreasing trends at the 2 other sites, possibly influenced by low recruitment. Insight into declining species management can be gained from information on survival and recruitment and how site-specific environmental factors influence these demographic parameters. Our data are particularly useful because they provide baseline data on demographics in populations before a disease outbreak and enhance our ability to detect changes

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

Treesearch

Cathryn H. Greenberg; George W. Tanner

2004-01-01

Eastern Spadefoot Toads (Scaphiopus holbrookii) require fish-free, isolated, ephemeral ponds for breeding but otherwise inhabit surrounding uplands, commonly xeric longleaf pine (Pinus palustris) and wiregrass (Aristida beyrichiana) ecosystem. Fire suppression in the Florida sandhills has the potential to alter...

Phylogeography of the smooth-coated otter (Lutrogale perspicillata): distinct evolutionary lineages and hybridization with the Asian small-clawed otter (Aonyx cinereus)

PubMed Central

Moretti, Beatrice; Al-Sheikhly, Omar F.; Guerrini, Monica; Theng, Meryl; Gupta, Brij K.; Haba, Mukhtar K.; Khan, Waseem A.; Khan, Aleem A.; Barbanera, Filippo

2017-01-01

We investigated the phylogeography of the smooth-coated otter (Lutrogale perspicillata) to determine its spatial genetic structure for aiding an adaptive conservation management of the species. Fifty-eight modern and 11 archival (dated 1882–1970) otters sampled from Iraq to Malaysian Borneo were genotyped (mtDNA Cytochrome-b, 10 microsatellite DNA loci). Moreover, 16 Aonyx cinereus (Asian small-clawed otter) and seven Lutra lutra (Eurasian otter) were sequenced to increase information available for phylogenetic reconstructions. As reported in previous studies, we found that L. perspicillata, A. cinereus and A. capensis (African clawless otter) grouped in a clade sister to the genus Lutra, with L. perspicillata and A. cinereus being reciprocally monophyletic. Within L. perspicillata, we uncovered three Evolutionarily Significant Units and proved that L. p. maxwelli is not only endemic to Iraq but also the most recent subspecies. We suggest a revision of the distribution range limits of easternmost L. perspicillata subspecies. We show that smooth-coated otters in Singapore are L. perspicillata x A. cinereus hybrids with A. cinereus mtDNA, the first reported case of hybridization in the wild among otters. This result also provides evidence supporting the inclusion of L. perspicillata and A. cinereus in the genus Amblonyx, thus avoiding the paraphyly of the genus Aonyx. PMID:28128366

Phylogeography of the smooth-coated otter (Lutrogale perspicillata): distinct evolutionary lineages and hybridization with the Asian small-clawed otter (Aonyx cinereus).

PubMed

Moretti, Beatrice; Al-Sheikhly, Omar F; Guerrini, Monica; Theng, Meryl; Gupta, Brij K; Haba, Mukhtar K; Khan, Waseem A; Khan, Aleem A; Barbanera, Filippo

2017-01-27

We investigated the phylogeography of the smooth-coated otter (Lutrogale perspicillata) to determine its spatial genetic structure for aiding an adaptive conservation management of the species. Fifty-eight modern and 11 archival (dated 1882-1970) otters sampled from Iraq to Malaysian Borneo were genotyped (mtDNA Cytochrome-b, 10 microsatellite DNA loci). Moreover, 16 Aonyx cinereus (Asian small-clawed otter) and seven Lutra lutra (Eurasian otter) were sequenced to increase information available for phylogenetic reconstructions. As reported in previous studies, we found that L. perspicillata, A. cinereus and A. capensis (African clawless otter) grouped in a clade sister to the genus Lutra, with L. perspicillata and A. cinereus being reciprocally monophyletic. Within L. perspicillata, we uncovered three Evolutionarily Significant Units and proved that L. p. maxwelli is not only endemic to Iraq but also the most recent subspecies. We suggest a revision of the distribution range limits of easternmost L. perspicillata subspecies. We show that smooth-coated otters in Singapore are L. perspicillata x A. cinereus hybrids with A. cinereus mtDNA, the first reported case of hybridization in the wild among otters. This result also provides evidence supporting the inclusion of L. perspicillata and A. cinereus in the genus Amblonyx, thus avoiding the paraphyly of the genus Aonyx.

Identification of a candidate CD5 homologue in the amphibian Xenopus laevis.

PubMed

Jürgens, J B; Gartland, L A; Du Pasquier, L; Horton, J D; Göbel, T W; Cooper, M D

1995-11-01

We identified a novel T cell Ag in the South African clawed toad (Xenopus laevis) by a mAb designated 2B1. This Ag is present in relatively high levels on most thymocytes, approximately 65% of splenocytes, 55% of PBL, and 65% of intestinal lymphocytes, but is rarely seen on IgM+ B cells in any of these tissues. Lymphocytes bearing the 2B1 Ag proliferate in response to stimulation with Con A or PHA, whereas the 2B1- lymphocytes are reactive to LPS. Biochemical analysis indicates that this Ag is a differentially phosphorylated glycoprotein of 71 to 82 kDa. The protein core of 64 kDa bears both N- and O-linked carbohydrate side chains. The amino-terminal protein sequence of the 2B1 Ag shares significant homology with both the macrophage scavenger receptor type 1 motif and the mammalian CD5/CD6 family. The biochemical characteristics and cellular distribution of the 2B1 Ag suggest that it represents the CD5 homologue in X. laevis. While T cells constitutively express this highly conserved molecule, Xenopus B cells acquire the CD5 homologue only when they are stimulated in the presence of T cells.

Propagation method of saving valuable strains from a Mycobacterium liflandii infection in Western clawed frogs (Silurana tropicalis).

PubMed

Chai, Norin; Bronchain, Odile; Panteix, Gilles; Godreuil, Sylvain; de Medeiros, Christophe; Saunders, Richard; Bouts, Tim; de Luze, Amaury

2012-03-01

Mycobacterium liflandii has been responsible for an emerging infection reported in the international trade of Western clawed frogs (Silurana tropicalis). This study shows that this mycolactone-producing Mycobacterium (MPM) has expanded its distribution range to France. The results of this study suggest that the use of in vitro fertilization to maintain genetic lines could be a temporary solution for valuable S. tropicalis propagation.

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

Treesearch

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

2004-01-01

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

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

PubMed

Fonovich de Schroeder, Teresa M

2005-02-01

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

A Systematic Review of Human Bat Rabies Virus Variant Cases: Evaluating Unprotected Physical Contact with Claws and Teeth in Support of Accurate Risk Assessments.

PubMed

Dato, Virginia M; Campagnolo, Enzo R; Long, Jonah; Rupprecht, Charles E

2016-01-01

In the United States and Canada, the most recent documented cases of rabies have been attributed to bat rabies viruses (RABV). We undertook this systematic review in an effort to summarize and enhance understanding of the risk of infection for individuals who have been potentially exposed to a suspect or confirmed rabid bat. United States rabies surveillance summaries documented a total of 41 human bat-rabies virus variant verified non-transplant cases between 1990 and 2015. All cases were fatal. Seven (17.1%) of 41 cases reported a bite from a bat. Ten (24.3%) cases had unprotected physical contact (UPC); these included seven cases that had a bat land or crawl on them (contact with claws) and one case that touched a bat's teeth. Seven (17.1%) cases had probable UPC. Insectivorous bat teeth are extremely sharp and highly efficient for predation upon arthropod prey. Bats also have sharp claws on the end of their thumbs and feet. One of the most common bat RABV variants has an ability to replicate in non-neural cells. Questioning individuals about unprotected contact with bat teeth and claws (including a bat landing or crawling on a person) may help identify additional exposures.

A Systematic Review of Human Bat Rabies Virus Variant Cases: Evaluating Unprotected Physical Contact with Claws and Teeth in Support of Accurate Risk Assessments

PubMed Central

Campagnolo, Enzo R.; Long, Jonah; Rupprecht, Charles E.

2016-01-01

In the United States and Canada, the most recent documented cases of rabies have been attributed to bat rabies viruses (RABV). We undertook this systematic review in an effort to summarize and enhance understanding of the risk of infection for individuals who have been potentially exposed to a suspect or confirmed rabid bat. United States rabies surveillance summaries documented a total of 41 human bat-rabies virus variant verified non-transplant cases between 1990 and 2015. All cases were fatal. Seven (17.1%) of 41 cases reported a bite from a bat. Ten (24.3%) cases had unprotected physical contact (UPC); these included seven cases that had a bat land or crawl on them (contact with claws) and one case that touched a bat’s teeth. Seven (17.1%) cases had probable UPC. Insectivorous bat teeth are extremely sharp and highly efficient for predation upon arthropod prey. Bats also have sharp claws on the end of their thumbs and feet. One of the most common bat RABV variants has an ability to replicate in non-neural cells. Questioning individuals about unprotected contact with bat teeth and claws (including a bat landing or crawling on a person) may help identify additional exposures. PMID:27459720

THE ANATOMIC SITE OF THE TRANSEPITHELIAL PERMEABILITY BARRIERS OF TOAD BLADDER

PubMed Central

DiBona, Donald R.; Civan, Mortimer M.; Leaf, Alexander

1969-01-01

An examination of the mucosal epithelium of the urinary bladder of the toad reveals that the two major cell types which abut on the urinary surface, the granular and mitochondria-rich cells, also contact the basement membrane. Thus, the epithelium functions as a single cell layer. Although basal cells are interpolated between the granular cells and the basement membrane over a large portion of the epithelium, they do not constitute an additional continuous cell layer. This finding is consistent with extensive physiological data which had assumed that the major permeability barriers of this epithelium were the apical and basal-lateral plasma membranes of a single layer of cells. PMID:5782445

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

PubMed

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

2012-06-01

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

Effects of metal and predator stressors in larval southern toads (Anaxyrus terrestris).

PubMed

Rumrill, Caitlin T; Scott, David E; Lance, Stacey L

2016-08-01

Natural and anthropogenic stressors typically do not occur in isolation; therefore, understanding ecological risk of contaminant exposure should account for potential interactions of multiple stressors. Realistically, common contaminants can also occur chronically in the environment. Because parental exposure to stressors may cause transgenerational effects on offspring, affecting their ability to cope with the same or novel environmental stressors, the exposure histories of generations preceding that being tested should be considered. To examine multiple stressor and parental exposure effects we employed a 2 × 2 × 2 factorial design in outdoor 1000-L mesocosms (n = 24). Larval southern toads (Anaxyrus terrestris), bred from parents collected from reference and metal-contaminated sites, were exposed to two levels of both an anthropogenic (copper-0, 30 µg/L Cu) and natural (predator cue - present/absent) stressor and reared to metamorphosis. Toads from the metal-contaminated parental source population were smaller at metamorphosis and had delayed development; i.e., a prolonged larval period. Similarly, larval Cu exposure also reduced size at metamorphosis and prolonged the larval period. We, additionally, observed a significant interaction between larval Cu and predator-cue exposure on larval period, wherein delayed emergence was only present in the 30-µg/L Cu treatments in the absence of predator cues. The presence of parental effects as well as an interaction between aquatic stressors on commonly measured endpoints highlight the importance of conducting multistressor studies across generations to obtain data that are more relevant to field conditions in order to determine population-level effects of contaminant exposure.

Aromatic claw: A new fold with high aromatic content that evades structural prediction: Aromatic Claw

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

Sachleben, Joseph R.; Adhikari, Aashish N.; Gawlak, Grzegorz

2016-11-10

We determined the NMR structure of a highly aromatic (13%) protein of unknown function, Aq1974 from Aquifex aeolicus (PDB ID: 5SYQ). The unusual sequence of this protein has a tryptophan content five times the normal (six tryptophan residues of 114 or 5.2% while the average tryptophan content is 1.0%) with the tryptophans occurring in a WXW motif. It has no detectable sequence homology with known protein structures. Although its NMR spectrum suggested that the protein was rich in β-sheet, upon resonance assignment and solution structure determination, the protein was found to be primarily α-helical with a small two-stranded β-sheet withmore » a novel fold that we have termed an Aromatic Claw. As this fold was previously unknown and the sequence unique, we submitted the sequence to CASP10 as a target for blind structural prediction. At the end of the competition, the sequence was classified a hard template based model; the structural relationship between the template and the experimental structure was small and the predictions all failed to predict the structure. CSRosetta was found to predict the secondary structure and its packing; however, it was found that there was little correlation between CSRosetta score and the RMSD between the CSRosetta structure and the NMR determined one. This work demonstrates that even in relatively small proteins, we do not yet have the capacity to accurately predict the fold for all primary sequences. The experimental discovery of new folds helps guide the improvement of structural prediction methods.« less

Analysis of the respiratory component of heart rate variability in the Cururu toad Rhinella schneideri.

PubMed

Zena, Lucas A; Leite, Cléo A C; Longhini, Leonardo S; Dias, Daniel P M; da Silva, Glauber S F; Hartzler, Lynn K; Gargaglioni, Luciane H; Bícego, Kênia C

2017-11-23

Beat-to-beat variation in heart rate (f H ) has been used as a tool for elucidating the balance between sympathetic and parasympathetic modulation of the heart. A portion of the temporal changes in f H is evidenced by a respiratory influence (cardiorespiratory interaction) on heart rate variability (HRV) with heartbeats increasing and decreasing within a respiratory cycle. Nevertheless, little is known about respiratory effects on HRV in lower vertebrates. By using frequency domain analysis, we provide the first evidence of a ventilatory component in HRV similar to mammalian respiratory sinus arrhythmia in an amphibian, the toad Rhinella schneideri. Increases in the heartbeats arose synchronously with each lung inflation cycle, an intermittent breathing pattern comprised of a series of successive lung inflations. A well-marked peak in the HRV signal matching lung inflation cycle was verified in toads whenever lung inflation cycles exhibit a regular rhythm. The cardiac beat-to-beat variation evoked at the moment of lung inflation accounts for both vagal and sympathetic influences. This cardiorespiratory interaction may arise from interactions between central and peripheral feedback mechanisms governing cardiorespiratory control and may underlie important cardiorespiratory adjustments for gas exchange improvement especially under extreme conditions like low oxygen availability.

Duration of extinction trials as a determinant of instrumental extinction in terrestrial toads (Rhinella arenarum).

PubMed

Puddington, Martín M; Papini, Mauricio R; Muzio, Rubén N

2018-01-01

Instrumental learning guides behavior toward resources. When such resources are no longer available, approach to previously reinforced locations is reduced, a process called extinction. The present experiments are concerned with factors affecting the extinction of acquired behaviors in toads. In previous experiments, total reward magnitude in acquisition and duration of extinction trials were confounded. The present experiments were designed to test the effects of these factors in factorial designs. Experiment 1 varied reward magnitude (900, 300, or 100 s of water access per trial) and amount of acquisition training (5 or 15 daily trials). With total amount of water access equated in acquisition, extinction with large rewards was faster (longer latencies in 900/5 than 300/15), but with total amount of training equated, extinction with small rewards was faster (longer latencies in 100/15 than 300/15). Experiment 2 varied reward magnitude (1200 or 120 s of water access per trial) while holding constant the number of acquisition trials (5 daily trials) and the duration of extinction trials (300 s). Extinction performance was lower with small, rather than large reward magnitude (longer latencies in 120/300 than in 1200/300). Thus, instrumental extinction depends upon the amount of time toads are exposed to the empty goal compartment during extinction trials.

Differential sensitivity to the antifouling chemical medetomidine between wood frog and American toad tadpoles with evidence for low-dose stimulation and high-dose inhibition of metamorphosis.

PubMed

Fong, Peter P; Lambert, Olivia J; Hoagland, Margot L; Kurtz, Emily R

2018-05-05

Antifouling chemicals are legacy contaminants in aquatic ecosystems. Previous experiments have shown that a 14-day exposure to the antifouling chemical medetomidine delays metamorphosis and reduces body mass in wood frog tadpoles. In the present study, we exposed wood frog tadpoles to medetomidine for 3, 7, and 10 days at 100 nM, 1 μM, and 10 μM. We also exposed American toad tadpoles to medetomidine for 3 days at four concentrations (10 nM, 100 nM, 1 μM, and 10 μM) in static renewal experiments. In each experiment, we measured growth, frequency and time to metamorphosis, and mass at metamorphosis. In both species, medetomidine significantly slowed development as measured by the Gosner stage. After 34 days in culture, wood frog tadpoles exposed to 1 and 10 μM medetomidine for as few as 3 days were significantly less developed compared to controls. Toads exposed to 1 μM medetomidine for 3 days were also significantly less developed on day 27, but by day 34, there was no difference from controls. For wood frogs, medetomidine significantly affected time to metamorphosis with a trend for tadpoles at lower concentrations metamorphosing sooner than those at higher concentrations. While medetomidine affected time to metamorphosis in wood frogs, it did not affect fresh mass, dry mass, or mortality compared to controls. Wood frog tadpoles that did not metamorphose after over 90 days in culture were more frequent in high-concentration groups than in the control. In toads, 10 μM medetomidine was 100% lethal within 23 days, but at the same concentration and duration, no wood frog tadpoles died. Lower concentrations were also significantly lethal to toads compared to controls, but tadpoles that survived in 10 and 100 nM metamorphosed sooner than those in 1 μM. Fresh mass of toad tadpoles exposed to 1 μm was significantly smaller at metamorphosis compared to that of controls. Medetomidine also affected the behavior of tadpoles. In toads, medetomidine

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

PubMed

Martin, D S; Desser, S S

1990-01-01

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

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

USGS Publications Warehouse

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

2012-01-01

1. Ecologists have long been interested in the processes that determine patterns of species occurrence and co-occurrence. Potential short-comings of many existing empirical approaches that address these questions include a reliance on patterns of occurrence at a single time point, failure to account properly for imperfect detection and treating the environment as a static variable.2. We fit detection and non-detection data collected from repeat visits using a dynamic site occupancy model that simultaneously accounts for the temporal dynamics of a focal prey species, its predators and its habitat. Our objective was to determine how disturbance and species interactions affect the co-occurrence probabilities of an endangered toad and recently introduced non-native predators in stream breeding habitats. For this, we determined statistical support for alternative processes that could affect co-occurrence frequency in the system.3. We collected occurrence data at stream segments in two watersheds where streams were largely ephemeral and one watershed dominated by perennial streams. Co-occurrence probabilities of toads with non-native predators were related to disturbance frequency, with low co-occurrence in the ephemeral watershed and high co-occurrence in the perennial watershed. This occurred because once predators were established at a site, they were rarely lost from the site except in cases when the site dried out. Once dry sites became suitable again, toads colonized them much more rapidly than predators, creating a period of predator-free space.4. We attribute the dynamics to a storage effect, where toads persisting outside the stream environment during periods of drought rapidly colonized sites when they become suitable again. Our results support that even in highly connected stream networks, temporal disturbance can structure frequencies with which breeding amphibians encounter non-native predators.5. Dynamic multi-state occupancy models are a powerful

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

PubMed

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

2012-11-01

1. Ecologists have long been interested in the processes that determine patterns of species occurrence and co-occurrence. Potential short-comings of many existing empirical approaches that address these questions include a reliance on patterns of occurrence at a single time point, failure to account properly for imperfect detection and treating the environment as a static variable. 2. We fit detection and non-detection data collected from repeat visits using a dynamic site occupancy model that simultaneously accounts for the temporal dynamics of a focal prey species, its predators and its habitat. Our objective was to determine how disturbance and species interactions affect the co-occurrence probabilities of an endangered toad and recently introduced non-native predators in stream breeding habitats. For this, we determined statistical support for alternative processes that could affect co-occurrence frequency in the system. 3. We collected occurrence data at stream segments in two watersheds where streams were largely ephemeral and one watershed dominated by perennial streams. Co-occurrence probabilities of toads with non-native predators were related to disturbance frequency, with low co-occurrence in the ephemeral watershed and high co-occurrence in the perennial watershed. This occurred because once predators were established at a site, they were rarely lost from the site except in cases when the site dried out. Once dry sites became suitable again, toads colonized them much more rapidly than predators, creating a period of predator-free space. 4. We attribute the dynamics to a storage effect, where toads persisting outside the stream environment during periods of drought rapidly colonized sites when they become suitable again. Our results support that even in highly connected stream networks, temporal disturbance can structure frequencies with which breeding amphibians encounter non-native predators. 5. Dynamic multi-state occupancy models are a powerful tool

Application of Focused Ultrasound-Assisted Extraction for the Quantification of Persistent Organic Pollutions in Liver Tissue of Giant Toad (Rhinella marina).

PubMed

Flores-Ramírez, R; Espinosa-Reyes, G; Cilia-López, V G; González-Mille, D J; Rodríguez-Aguilar, M; Díaz de León-Martínez, L; Díaz-Barriga, F

2017-02-01

A simple and rapid focused ultrasound extraction method was developed for the determination of Persistent Organic Pollutants (POPs) in liver tissue obtained of giant toad (Rhinella marina) using a gas chromatography coupled to a mass detector with electron impact ionization. The performed method for POPs, was validated in fortified matrix, showing linearity from the LOQ up to 100 ng/mL; LODs and LOQs for each compound were between 1.7 and 4.8 and 3.5-7.5 ng/mL, respectively. Recovery rates were among 79%-116% for POPs determined. Finally, the method was applied in liver samples of giant toads found in a malarial area in Mexico. The sensitivity of the proposed method was good enough to ensure reliable determination of target analytes at concentration levels commonly found in this kind of samples.

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

Treesearch

Blake R. Hossack; Paul Stephen Corn

2008-01-01

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

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

Treesearch

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

2008-01-01

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

The GeoClaw software for depth-averaged flows with adaptive refinement

USGS Publications Warehouse

Berger, M.J.; George, D.L.; LeVeque, R.J.; Mandli, Kyle T.

2011-01-01

Many geophysical flow or wave propagation problems can be modeled with two-dimensional depth-averaged equations, of which the shallow water equations are the simplest example. We describe the GeoClaw software that has been designed to solve problems of this nature, consisting of open source Fortran programs together with Python tools for the user interface and flow visualization. This software uses high-resolution shock-capturing finite volume methods on logically rectangular grids, including latitude-longitude grids on the sphere. Dry states are handled automatically to model inundation. The code incorporates adaptive mesh refinement to allow the efficient solution of large-scale geophysical problems. Examples are given illustrating its use for modeling tsunamis and dam-break flooding problems. Documentation and download information is available at www.clawpack.org/geoclaw. ?? 2011.

Microanatomy of passerine hard-cornified tissues: Beak and claw structure of the black-capped chickadee (Poecile atricapillus)

USGS Publications Warehouse

Van Hemert, C.; Handel, Colleen M.; Blake, J.E.; Swor, R.M.; O'Hara, T. M.

2012-01-01

The microanatomy of healthy beaks and claws in passerine birds has not been well described in the literature, despite the importance of these structures in avian life. Histological processing of hard-cornified tissues is notoriously challenging and only a few reports on effective techniques have been published. An emerging epizootic of beak deformities among wild birds in Alaska and the Pacific Northwest region of North America recently highlighted the need for additional baseline information about avian hard-cornified structures. In this study, we examine the beak and claw of the Black-capped Chickadee (Poecile atricapillus), a common North American passerine that is affected by what has been described as "avian keratin disorder." We use light and scanning electron microscopy and high-magnification radiography to document the healthy microanatomy of these tissues and identify features of functional importance. We also describe detailed methods for histological processing of avian hard-cornified structures and discuss the utility of special stains. Results from this study will assist in future research on the functional anatomy and pathology of hard-cornified structures and will provide a necessary reference for ongoing investigations of avian keratin disorder in Black-capped Chickadees and other wild passerine species. ?? 2011 Wiley Periodicals, Inc.

Microanatomy of Passerine hard-cornified tissues: beak and claw structure of the Black-capped Chickadee (Poecile atricapillus)

USGS Publications Warehouse

Van Hemert, Caroline R.; Handel, Colleen M.; Blake, J.; Swor, Rhonda; O'Hara, Todd M.

2012-01-01

The microanatomy of healthy beaks and claws in passerine birds has not been well described in the literature, despite the importance of these structures in avian life. Histological processing of hard-cornified tissues is notoriously challenging and only a few reports on effective techniques have been published. An emerging epizootic of beak deformities among wild birds in Alaska and the Pacific Northwest region of North America recently highlighted the need for additional baseline information about avian hard-cornified structures. In this study, we examine the beak and claw of the Black-capped Chickadee (Poecile atricapillus), a common North American passerine that is affected by what has been described as “avian keratin disorder.” We use light and scanning electron microscopy and high-magnification radiography to document the healthy microanatomy of these tissues and identify features of functional importance. We also describe detailed methods for histological processing of avian hard-cornified structures and discuss the utility of special stains. Results from this study will assist in future research on the functional anatomy and pathology of hard-cornified structures and will provide a necessary reference for ongoing investigations of avian keratin disorder in Black-capped Chickadees and other wild passerine species.

Tadpole of the Critically Endangered Sterling's Toothed Toad (Oreolalax sterlingae).

PubMed

Rowley, Jodi J L; Tapley, Benjamin; Chung, Nguyen Thanh; Altig, Ronald

2017-05-31

Sterling's Toothed Toad, Oreolalax sterlingae (Nguyen et al. 2013), was described from near the summit of the highest peak in Vietnam, Mount Fansipan, Lao Cai Province. The species is the only member of the genus in Vietnam and is presently known from a single stream system on Mount Fansipan at about 2800 m elevation. The closest congener occurs more than 200 km away in China (Fei et al. 2010), and the relationship of O. sterlingae within the genus is not known. Because of its extremely small range and profound habitat modifications and pollution at the site, O. sterlingae was recently assessed as Critically Endangered (IUCN SSC 2015).

Energetics of sodium transport in toad urinary bladder.

PubMed Central

Canessa, M; Labarca, P; DiBona, D R; Leaf, A

1978-01-01

The ratio of the rate of transepithelial sodium transport, JNa, across the isolated toad urinary bladder to the simultaneously measured rate of transport-dependent metabolism, JsbCO2, has been measured as a function of the transepithelial electrical voltage, deltapsi. The ratio remains constant with a mean value of 18 to 20 over the range of imposed voltages of 0 to +70 mV. With increasing hyperpolarization of the bladder, JNa decreases and the calculated electromotive force or apparent "ENa" of the sodium pump increases. From thermodynamic and kinetic arguments it is shown that the apparent "ENa" approaches the maximal electrochemical potential gradient, ENa, against which sodium can be transported by this tissue only when JNa approximately 0. At this unique condition F ENa (in which F is the Faraday constant) is the maximal free energy of the chemical reaction driving sodium transport and thus equal to the maximal extramitochondrial phosphorylation potential and the maximal free energy of the mitochondrial respiratory chain within the transporting cells. PMID:100789

Effect of biotin supplementation on claw horn growth in young, clinically healthy cattle

PubMed Central

da Silva, Luiz Antônio Franco; Franco, Leandro Guimarães; Atayde, Ingrid Bueno; da Cunha, Paulo Henrique Jorge; de Moura, Maria Ivete; Goulart, Daniel Silva

2010-01-01

The effects of orally administered biotin supplementation on the growth of claw horn in young, clinically healthy cattle were analyzed. Twelve, 1-year-old Girolando cattle were randomly assigned to receive either 12.5 mg of diluted powdered biotin (GI) or a control treatment (GII) for 40 consecutive days. Cattle in the GI group showed an average hoof growth of 11.3 ± 0.72 mm, while those in GII had an average hoof growth of 7.2 ± 0.78 mm. The results confirmed the positive effect of biotin supplementation on the growth of angle and length of the dorsal hoof wall, hoof sole length, and on resistance to wearing, in young cattle extensively managed. PMID:20808571

Effects of rearing environment and population origin on responses to repeated behavioural trials in cane toads (Rhinella marina).

PubMed

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

2018-05-02

Behavioural response to repeated trials in captivity can be driven by many factors including rearing environment, population of origin, habituation to captivity/trial conditions and an individual's behavioural type (e.g., bold versus shy). We tested the effect of rearing environment (captive raised common-garden versus wild-caught) and population origin (range-edge versus range-front) on the responses of invasive cane toads (Rhinella marina) to repeated exploration and risk-taking assays in captivity. We found that behavioural responses to identical assays performed on two occasions were complex and showed few consistent patterns based on rearing environment or population of origin. However, behavioural traits were repeatable across Trial Blocks when all sample populations were grouped together, indicating general consistency in individual toad behaviour across repeated behavioural assays. Our findings exemplify the complexity and unpredictability of behavioural responses and their effects on the repeatability and interpretation of behavioural traits across repeated behavioural assays in captivity. To meaningfully interpret the results from repeated behavioural assays, we need to consider how multiple factors may affect behavioural responses to these tests and importantly, how these responses may affect the repeatability of behavioural traits across time. Copyright © 2018. Published by Elsevier B.V.

The Wisconsin Frog and Toad Survey: Update and 1984-97 trends [abstract

USGS Publications Warehouse

Mossman, M.J.; Hartman, L.; Sauer, J.; Hay, R.; Dhuey, B.

1998-01-01

The Wisconsin Frog and Toad Survey (WFTS) is a volunteer-based, roadside auditory count that began in 1981. It's protocols were recently modified for continent-wide use by the North American Amphibian Monitoring Plan (NAAMP). In 1997 we initiated a study to compare data collected by the WFTS and NAAMP protocols, in order to guide WFTS transition from its current methodology to one more compatible with NAAMP, without losing the use of data collected since 1981. In this paper we present results from the first year of this study, along with results from analyses of WFTS data, including distributional maps, 1984-97 population trends, phenological information, and progress on a new web page.

Identification of an anti-lipopolysacchride factor possessing both antiviral and antibacterial activity from the red claw crayfish Cherax quadricarinatus.

PubMed

Lin, Feng-Yu; Gao, Yan; Wang, Hao; Zhang, Qiu-Xia; Zeng, Chang-Lin; Liu, Hai-Peng

2016-10-01

It is well-known that anti-lipopolysacchride factors (ALFs) are involved in the recognition and elimination of invading pathogens. In this study, the full-length ALF cDNA sequence of the red claw crayfish Cherax quadricarinatus (termed CqALF) was cloned from a suppression subtractive hybridization library constructed using red claw crayfish hematopoietic tissue cell (Hpt cell) cultures following challenge with white spot syndrome virus (WSSV). The full-length cDNA sequence of CqALF was 863 bp, and the open reading frame encoded 123 amino acids with a signal peptide in the N-terminus and a conserved LPS-binding domain. Unlike most ALFs, which are highly expressed in haemocytes, high expression levels of CqALF were detected in epithelium, the stomach and eyestalks, while lower expression was detected in Hpt, nerves, the heart, muscle tissue, gonads, haemocytes, intestines, gills and the hepatopancreas. To further explore the biological activities of CqALF, mature recombinant CqALF protein (rCqALF) was expressed and purified using a eukaryotic expression system, and an antimicrobial activity test was carried out. rCqALF clearly exerted antiviral activity, as evidenced by the severe disruption of the envelope of intact WSSV virions following co-incubation of virions with rCqALF. Additionally, pre-incubation of WSSV with rCqALF resulted in both a significant reduction in WSSV replication in red claw crayfish Hpt cell cultures and an increased survival rate among animals. Furthermore, rCqALF was effective against both Gram-negative bacteria and Gram-positive bacteria, particularly Shigella flexneri and Staphylococcus aureus. A membrane integrity assay suggested that rCqALF was unlikely to disrupt bacterial membrane integrity compared to cecropin P1. Taken together, these data suggest that CqALF may play an important role in immune defence in the crustacean C. quadricarinatus. Copyright © 2016 Elsevier Ltd. All rights reserved.

Behavioural and biochemical investigations of the influence of altered gravity on the CNS of aquatic vertebrates during ontogeny

NASA Astrophysics Data System (ADS)

Slenzka, K.; Appel, R.; Hilbig, R.; Kappel, Th.; Vetter, S.; Freischütz, B.; Rahmann, H.

1994-08-01

Quantitative data are presented on the influences of hyper-gravity (3+/-1g) and of simulated weightlessness (~0g) during early ontogeny of cichild fish (Oreochromis mossambicus) and clawed toad (Xenopus laevis, Daudin) demonstrating changes in the swimming behaviour and the brain energy and plasma membrane metabolism. After return to 1g conditions, hyper-g reared fish and toads express the well known ``loop-swimming'' behaviour. By means of a computer based video analyzing system different types of swimming movements and velocities were quantitatively determined. Analyses of the brain energy and plasma-membrane metabolism of hyper-g fish larvae demonstrated an increase in energy availability (glucose 6Pi dehydrogenase, G-6P-DH), a decrease of cellular energy transformation (creatine kinase activity, CK) but no changes in energy consumptive processes (e.g. ATPases) and cytochrome oxidase activity (Cyt.-Ox). In contrast hypo-g fish larvae showed a slight increase in brain CK activity. In addition, unlike 1g controls, hyper-g fish larvae showed pronounced variations in the composition (=polarity) of sialoglycosphingolipids (=gangliosides), typical constituents of the nerve cell membranes, and a slight increase in the activity of sialidase, the enzyme responsible for ganglioside degradation.

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

PubMed

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

2003-11-01

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

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

EPA Science Inventory

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

The effects of microgravity on gametogenesis, fertilization, and early embryogenesis

NASA Astrophysics Data System (ADS)

Tan, X.

Gametogenesis fertilization and early embryogenesis are crucial periods for normal development afterwards In past three decades many experiments have been conducted in space and in simulated weightlessness induced by clinostats to elucidate the issue Different animal species including Drosophila wasp shrimp fish amphibian mouse rats etc have been used for the study Oogenesis and spermatogenesis are affected by microgravity in different ways Some researches found that microgravity condition perturbed the process of oogenesis in many species A significant increased frequency of chromosomal non-disjunction was found in Drosophila females resulting the loss of chromosomes during meiosis and inhibition of cell division Studies on wasp showed a decreased hatchability and accumulation of unhatched eggs when the insects were exposed to spaceflight at different stages of oogenesis For experiments conducted on vertebrate animal models the results are somehow different however Microgravity has no significant effect for fish Medaka etc amphibian South African clawed toad Xenopus laevis or mammals mouse Spermatogenesis on the other hand is more significantly affected by microgravity condition Some researches indicated sperm are sensitive to changes in gravitational force and this sensitivity affects the ability of sperm to fertilize eggs Sperm swim with higher velocity in microgravity which is coupled with altered protein phosphorylation level in sperm under microgravity condition Microgravity also induced activation of the

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

PubMed

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

2011-09-01

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

Associations of water balance and thermal sensitivity of toads with macroclimatic characteristics of geographical distribution.

PubMed

Titon, Braz; Gomes, Fernando Ribeiro

2017-06-01

Interspecific variation in patterns of geographical distribution of phylogenetically related species of amphibians might be related to physiological adaptation to different climatic conditions. In this way, a comparative study of resistance to evaporative water loss, rehydration rates and sensitivity of locomotor performance to variations on hydration level and temperature was performed for five species of Bufonidae toads (Rhinella granulosa, R. jimi, R. ornata, R. schneideri and R. icterica) inhabiting different Brazilian biomes. The hypotheses tested were that, when compared to species inhabiting mesic environments, species living at hot and dry areas would show: (1) greater resistance to evaporative water loss, (2) higher rates of water uptake, (3) lower sensitivity of locomotor performance to dehydration and (4) lower sensitivity of locomotor performance at higher temperatures and higher sensitivity of locomotor performance at lower temperatures. This comparative analysis showed relations between body mass and interspecific variation in rehydration rates and resistance to evaporative water loss in opposite directions. These results might represent a functional compensation associated with relatively lower absorption areas in larger toads and higher evaporative areas in smaller ones. Moreover, species from the semi-arid Caatinga showed locomotor performance less sensitive to dehydration but highly affected by lower temperatures, as well greater resistance to evaporative water loss, when compared to the other species from the mesic Atlantic Forest and the savannah-like area called Cerrado. These results suggest adaptation patterns to environmental conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

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

USGS Publications Warehouse

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

2014-01-01

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

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

PubMed

Burcher, E; Warner, F J

1998-06-01

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

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

PubMed Central

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

1972-01-01

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

Effect of salinity on locomotor performance and thermal extremes of metamorphic Andean Toads (Rhinella spinulosa) from Monte Desert, Argentina.

PubMed

Sanabria, Eduardo; Quiroga, Lorena; Vergara, Cristina; Banchig, Mariana; Rodriguez, Cesar; Ontivero, Emanuel

2018-05-01

Rhinella spinulosa is distributed from Peru to Argentina (from 1200 to 5000 m elevation), inhabiting arid mountain valleys of the Andes, characterized by salty soils. The variations in soil salinity, caused by high evapotranspiration of water, can create an osmotic constraint and high thermal oscillations for metamorphsed Andean toad (R. spinulosa), affecting their thermoregulation and extreme thermal tolerances. We investigated the changes in thermal tolerance parameters (critical thermal maximum and crystallization temperature) of a population of metamorphosed R. spinulosa from the Monte Desert of San Juan, Argentina, under different substrate salinity conditions. Our results suggest that the locomotor performance of metamorphs of R. spinulosa is affected by increasing salinity concentrations in the environment where they develop. On the other hand, the thermal extremes of metamorphs of R. spinulosa also showed changes associated with different salinity conditions. According to other studies on different organisms, the increase of the osmolarity of the internal medium may increase the thermal tolerance of this species. More studies are needed to understand the thermo-osmolar adjustments of the metamorphs of toads to environmental variability. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bufadienolides from parotoid gland secretions of Cuban toad Peltophryne fustiger (Bufonidae): Inhibition of human kidney Na(+)/K(+)-ATPase activity.

PubMed

Perera Córdova, Wilmer H; Leitão, Suzana Guimarães; Cunha-Filho, Geraldino; Bosch, Roberto Alonso; Alonso, Isel Pascual; Pereda-Miranda, Rogelio; Gervou, Rodrigo; Touza, Natália Araújo; Quintas, Luis Eduardo M; Noël, François

2016-02-01

Parotoid gland secretions of toad species are a vast reservoir of bioactive molecules with a wide range of biological properties. Herein, for the first time, it is described the isolation by preparative reversed-phase HPLC and the structure elucidation by NMR spectroscopy and/or mass spectrometry of nine major bufadienolides from parotoid gland secretions of the Cuban endemic toad Peltophryne fustiger: ψ-bufarenogin, gamabufotalin, bufarenogin, arenobufagin, 3-(N-suberoylargininyl) marinobufagin, bufotalinin, telocinobufagin, marinobufagin and bufalin. In addition, the secretion was analyzed by UPLC-MS/MS which also allowed the identification of azelayl arginine. The effect of arenobufagin, bufalin and ψ-bufarenogin on Na(+)/K(+)-ATPase activity in a human kidney preparation was evaluated. These bufadienolides fully inhibited the Na(+)/K(+)-ATPase in a concentration-dependent manner, although arenobufagin (IC50 = 28.3 nM) and bufalin (IC50 = 28.7 nM) were 100 times more potent than ψ-bufarenogin (IC50 = 3020 nM). These results provided evidence about the importance of the hydroxylation at position C-14 in the bufadienolide skeleton for the inhibitory activity on the Na(+)/K(+)-ATPase. Published by Elsevier Ltd.

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

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

Cathryn H. Greenberg; George W. Tanner

2004-08-31

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 breedingmore » 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

Complete Genome Sequence of a Common Midwife Toad Virus-Like Ranavirus Associated with Mass Mortalities in Wild Amphibians in the Netherlands

PubMed Central

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

2014-01-01

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

Dark adaptation of toad rod photoreceptors following small bleaches.

PubMed

Leibrock, C S; Reuter, T; Lamb, T D

1994-11-01

The recovery of toad rod photoreceptors, following exposure to intense lights that bleached 0.02-3% of the rhodopsin, has been investigated using the suction pipette technique. The post-bleach period was accompanied by reduced flash sensitivity, accelerated kinetics, and spontaneous fluctuations (noise). The power spectrum of the fluctuations had substantially the form expected for the random occurrence of single-photon events, and the noise could therefore be expressed as a "photon-noise equivalent intensity". From the level of desensitization at any time, the after-effect of the bleach could also be expressed in terms of a "desensitization-equivalent intensity", and this was found to be at least a factor of 20 times higher than the noise-equivalent intensity at the corresponding time. Our results indicate that a bleach induces two closely-related phenomena: (a) a process indistinguishable from the effect of real light, and (b) another process which desensitizes and accelerates the response in the same way that light does, but without causing photon-like noise. We propose a mechanism underlying these processes.

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

DOE PAGES

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

2015-04-30

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

Membrane currents in the oocyte of the toad Bufo arenarum.

PubMed

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

2002-03-01

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

CONTRAST BETWEEN OSMIUM-FIXED AND PERMANGANATE-FIXED TOAD SPINAL GANGLIA

PubMed Central

Rosenbluth, Jack

1963-01-01

Chains of vesicles are prominent near the plasma membranes of both the neurons and satellite cells of osmium-fixed toad spinal ganglia. In permanganate-fixed specimens, however, such vesicles are absent, and in their place are continuous invaginations of the plasma membranes of these cells. The discrepancy suggests that the serried vesicles seen in osmium-fixed preparations arise through disintegration of plasma membrane invaginations, and do not represent active pinocytosis, as has been suggested previously. A second difference between ganglia fixed by these two methods is that rows of small, disconnected cytoplasmic globules occur in the sheaths of permanganate-fixed ganglia, but not in osmium-fixed samples. It is suggested that these globules arise from the breakdown of thin sheets of satellite cell cytoplasm which occur as continuous lamellae in osmium-fixed specimens. Possible mechanisms of these membrane reorganizations, and the relevance of these findings to other tissues, are discussed. PMID:13990905

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

USGS Publications Warehouse

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

2000-01-01

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

Biomarker analysis of American toad (Anaxyrus americanus) ...

EPA Pesticide Factsheets

The objective of the current study was to use a biomarker-based approach to investigate the influence of atrazine exposure on American toad (Anaxyrus americanus) and grey tree frog (Hyla versicolor) tadpoles. Atrazine is one of the most frequently detected herbicides in environmental matrices throughout the United States. In surface waters, it has been found at concentrations from 0.04–2859 μg/L and thus presents a likely exposure scenario for non-target species such as amphibians. Studies have examined the effect of atrazine on the metamorphic parameters of amphibians, however, the data are often contradictory. Gosner stage 22–24 tadpoles were exposed to 0 (control), 10, 50, 250 or 1250 μg/L of atrazine for 48 h. Endogenous polar metabolites were extracted and analyzed using gas chromatography coupled with mass spectrometry. Statistical analyses of the acquired spectra with machine learning classification models demonstrated identifiable changes in the metabolomic profiles between exposed and control tadpoles. Support vector machine models with recursive feature elimination created a more efficient, non-parametric data analysis and increased interpretability of metabolomic profiles. Biochemical fluxes observed in the exposed groups of both A. americanus and H. versicolor displayed perturbations in a number of classes of biological macromolecules including fatty acids, amino acids, purine nucleosides, pyrimidines, and mono- and di-saccharides. Metabolomic

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

PubMed

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

2012-01-01

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

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

USGS Publications Warehouse

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

2000-01-01

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

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

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

Zhang, Yong; Graduate School of Chinese Academy of Sciences, Beijing 100049; Yu, Guoyu

2010-07-30

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

Differential gene expression profile from haematopoietic tissue stem cells of red claw crayfish, Cherax quadricarinatus, in response to WSSV infection.

PubMed

Liu, Hai-peng; Chen, Rong-yuan; Zhang, Qiu-xia; Peng, Hui; Wang, Ke-jian

2011-07-01

White spot syndrome virus (WSSV) is one of the most important viral pathogens in crustaceans. During WSSV infection, multiple cell signaling cascades are activated, leading to the generation of antiviral molecules and initiation of programmed cell death of the virus infected cells. To gain novel insight into cell signaling mechanisms employed in WSSV infection, we have used suppression subtractive hybridization (SSH) to elucidate the cellular response to WSSV challenge at the gene level in red claw crayfish haematopoietic tissue (Hpt) stem cell cultures. Red claw crayfish Hpt cells were infected with WSSV for 1h (L1 library) and 12h (L12 library), respectively, after which the cell RNA was prepared for SSH using uninfected cells as drivers. By screening the L1 and L12 forward libraries, we have isolated the differentially expressed genes of crayfish Hpt cells upon WSSV infection. Among these genes, the level of many key molecules showed clearly up-regulated expression, including the genes involved in immune responses, cytoskeletal system, signal transduction molecules, stress, metabolism and homestasis related genes, and unknown genes in both L1 and L12 libraries. Importantly, of the 2123 clones screened, 176 novel genes were found the first time to be up-regulated in WSSV infection in crustaceans. To further confirm the up-regulation of differentially expressed genes, the semi-quantitative RT-PCR were performed to test twenty randomly selected genes, in which eight of the selected genes exhibited clear up-regulation upon WSSV infection in red claw crayfish Hpt cells, including DNA helicase B-like, multiprotein bridging factor 1, apoptosis-linked gene 2 and an unknown gene-L1635 from L1 library; coatomer gamma subunit, gabarap protein gene, tripartite motif-containing 32 and an unknown gene-L12-254 from L2 library, respectively. Taken together, as well as in immune and stress responses are regulated during WSSV infection of crayfish Hpt cells, our results also

Early Pliocene anuran fossils from Kanapoi, Kenya, and the first fossil record for the African burrowing frog Hemisus (Neobatrachia: Hemisotidae).

PubMed

Delfino, Massimo

2017-07-13

Isolated amphibian bones from the early Pliocene of Kanapoi (West Turkana, Kenya) help to improve the scarce fossil record of the late Neogene and Quaternary amphibians from East Africa. All currently available 579 bones are referable exclusively to the Anura (frogs and toads). More than half of the remains (366) are identified as Hemisus cf. Hemisus marmoratus, an extant species that still inhabits Kenya, but apparently not the northwest of the country and the Turkana area in particular. The rest of the remains are identified simply as Anura indet. because of poor preservation or non congruence with the relatively few African extant taxa whose osteology is known in detail. The Hemisus material represents the first fossil record for Hemisotidae, an endemic African family of peculiar, head-first burrowing frogs, whose sister taxon relationships indicate a divergence from brevicipitids in the Late Cretaceous or early Paleocene. The ecological requirements of extant H. marmoratus suggest that the Kanapoi area surrounding the fluvial and deltaic settings, from where the fossil remains of vertebrates were buried, was likely a grassland or relatively dry, open low tree-shrub savanna. Copyright © 2017 Elsevier Ltd. All rights reserved.

Uncaria tomentosa (cat's claw) improves quality of life in patients with advanced solid tumors.

PubMed

de Paula, Larissa Carvalho Lopes; Fonseca, Fernando; Perazzo, Fabio; Cruz, Felipe Melo; Cubero, Daniel; Trufelli, Damila Cristina; Martins, Suelen Patrícia Dos Santos; Santi, Patrícia Xavier; da Silva, Eliana Araújo; Del Giglio, Auro

2015-01-01

Cat's claw (Uncaria tomentosa) is a native Amazon plant that exhibits anti-inflammatory and antitumor properties. We wanted to assess its activity for symptom management of terminal cancer patients. This prospective phase II study assessed the effects of a 100-mg dose of a dry extract of U. tomentosa three times per day in patients with advanced solid tumors who had no further therapeutic options and a life expectancy of at least 2 months. The European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ C30) and Functional Assessment of Chronic Illness Therapy - Fatigue questionnaires were used to assess the participants' quality of life, the Hospital Anxiety and Depression Scale questionnaire was used to assess anxiety and depression, and the Pittsburgh Sleep Quality Index was used to assess sleep quality. In addition, several biochemical and inflammatory parameters were analyzed. Fifty-one volunteers were recruited. Their median age was 64 (range, 33-85) years, and 47% of patients were female. More than 65% of patients had scores on the Karnofsky Performance Scale of 80% or less. Treatment improved the patients' overall quality of life (p=0.0411) and social functioning (p=0.0341), as assessed by the EORTC QLQ C-30, and reduced fatigue (p=0.0496) according to the Chalder Fatigue Questionnaire. None of the biochemical or inflammatory parameters assessed (interleukin-1 and -6, C-reactive protein, tumor necrosis factor-α, erythrocyte sedimentation rate, and α-1-acid glycoprotein) changed significantly. No tumor response was detected according to the Response Evaluation Criteria In Solid Tumors; however, the disease stabilized for more than 8 months in four participants. The medication was well tolerated by most patients. Use of cat's claw might be beneficial in patients with advanced cancer by improving their quality of life and reducing fatigue. The mechanism of action does not seem to be related to the anti

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

PubMed Central

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

2016-01-01

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

Global gene expression during early differentiation of Xenopus (Silurana) tropicalis gonad tissues

EPA Science Inventory

African clawed frog Xenopus sp. has been used extensively for developmental biology and toxicology research. Xenopus (Silurana) tropicalis has been coveted more recently for genomics research because its diploid genome has been sequenced. Amid concerns of environmental pollutants...

Effects of landscape composition and wetland fragmentation on frog and toad abundance and species richness in Iowa and Wisconsin, USA [abstract

USGS Publications Warehouse

Knutson, M.G.; Sauer, J.R.; Olsen, D.A.; Mossman, M.J.; Hemesath, L.M.; Lannoo, M.J.

1998-01-01

We examined the relationships between anuran diversity and landscape features in the Upper Midwestern United States. Anuran relative abundance and species richness were measured using data collected by Wisconsin and Iowa state calling surveys conducted from 1990-1995. Landscape features surrounding survey points were determined using National Wetland Inventory and Wisconsin Wetland Inventory maps. We tested several hypotheses suggested by the literature. We hypothesized that the relative abundance and species richness of anurans that breed in ephemeral wetlands is positively correlated with the surrounding area of temporary wetlands and emergent wetlands. We hypothesized that the relative abundance and species richness of anurans is positively correlated with patch diversity and wetland edges, in the absence of local fragmentation effects. We hypothesized that the relative abundance and species richness of anurans is positively associated with forests but negatively associated with agriculture and urban areas. Our results show that the interspersion of different wetland types and the concomitant increase in wetland edge habitats were generally positive for frogs and toads and anuran abundance and diversity were generally higher in association with forests, especially forested wetlands. The presence of agriculture did not always depress frog and toad populations or diversity; some species were associated with agricultural landscapes. The two states differed in how anurans were associated with landscape features like lakes and permanent wetlands. We found that frog and toad relative abundance and diversity were lower when urban areas were present. Managers can use models like ours, generated from landscape analyses, along with range maps and population trend analyses to get a comprehensive picture of the health of individual species and groups of species. Our models could be applied to the landscape as a whole, and used to predict species relative abundance and

Earless toads sense low frequencies but miss the high notes.

PubMed

Womack, Molly C; Christensen-Dalsgaard, Jakob; Coloma, Luis A; Chaparro, Juan C; Hoke, Kim L

2017-10-11

Sensory losses or reductions are frequently attributed to relaxed selection. However, anuran species have lost tympanic middle ears many times, despite anurans' use of acoustic communication and the benefit of middle ears for hearing airborne sound. Here we determine whether pre-existing alternative sensory pathways enable anurans lacking tympanic middle ears (termed earless anurans) to hear airborne sound as well as eared species or to better sense vibrations in the environment. We used auditory brainstem recordings to compare hearing and vibrational sensitivity among 10 species (six eared, four earless) within the Neotropical true toad family (Bufonidae). We found that species lacking middle ears are less sensitive to high-frequency sounds, however, low-frequency hearing and vibrational sensitivity are equivalent between eared and earless species. Furthermore, extratympanic hearing sensitivity varies among earless species, highlighting potential species differences in extratympanic hearing mechanisms. We argue that ancestral bufonids may have sufficient extratympanic hearing and vibrational sensitivity such that earless lineages tolerated the loss of high frequency hearing sensitivity by adopting species-specific behavioural strategies to detect conspecifics, predators and prey. © 2017 The Author(s).

Cytoplasmic involvement in ADH-mediated osmosis across toad urinary bladder.

PubMed

DiBona, D R

1983-11-01

Several lines of investigation have suggested that antidiuretic hormone (ADH) may have direct effects on the cytoskeletal organization of granular epithelial cells in the toad urinary bladder. To some extent, these effects are in concert with the well-established action of ADH on the hydraulic permeability of the mucosal plasma membrane, but it appears that other conformational adjustments (largely cytoplasmic) may be of comparable importance. The thrust of this review is that the hormone brings about a general restructuring of the granular cells so that the epithelium as a whole may function efficiently as an osmotic pathway. Details of cytoskeletal changes are far from clear as yet, but interference with or modulation of these particular effects infer that cytoplasmic organization is the seat of feedback control of osmotic flow rate, the basis for viability in the presence of dramatic cytosolic dilution and a major factor in the observed disparity in osmotic and diffusional permeability coefficients. In the interest of stimulating new thoughts and experiments in this area, a number of preliminary findings have been freely cited.

Genomic regression of claw keratin, taste receptor and light-associated genes provides insights into biology and evolutionary origins of snakes.

PubMed

Emerling, Christopher A

2017-10-01

Regressive evolution of anatomical traits often corresponds with the regression of genomic loci underlying such characters. As such, studying patterns of gene loss can be instrumental in addressing questions of gene function, resolving conflicting results from anatomical studies, and understanding the evolutionary history of clades. The evolutionary origins of snakes involved the regression of a number of anatomical traits, including limbs, taste buds and the visual system, and by analyzing serpent genomes, I was able to test three hypotheses associated with the regression of these features. The first concerns two keratins that are putatively specific to claws. Both genes that encode these keratins are pseudogenized/deleted in snake genomes, providing additional evidence of claw-specificity. The second hypothesis is that snakes lack taste buds, an issue complicated by conflicting results in the literature. I found evidence that different snakes have lost one or more taste receptors, but all snakes examined retained at least one gustatory channel. The final hypothesis addressed is that the earliest snakes were adapted to a dim light niche. I found evidence of deleted and pseudogenized genes with light-associated functions in snakes, demonstrating a pattern of gene loss similar to other dim light-adapted clades. Molecular dating estimates suggest that dim light adaptation preceded the loss of limbs, providing some bearing on interpretations of the ecological origins of snakes. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of S-adenosylmethionine decarboxylase, polyamines, amino acids, and weak bases (amines and ammonia) on development and ribosomal RNA synthesis in Xenopus embryos.

PubMed

Shiokawa, Koichiro; Aso, Mai; Kondo, Takeshi; Takai, Jun-Ichi; Yoshida, Junki; Mishina, Takamichi; Fuchimukai, Kota; Ogasawara, Tsukasa; Kariya, Taro; Tashiro, Kosuke; Igarashi, Kazuei

2010-02-01

We have been studying control mechanisms of gene expression in early embryogenesis in a South African clawed toad Xenopus laevis, especially during the period of midblastula transition (MBT), or the transition from the phase of active cell division (cleavage stage) to the phase of extensive morphogenesis (post-blastular stages). We first found that ribosomal RNA synthesis is initiated shortly after MBT in Xenopus embryos and those weak bases, such as amines and ammonium ion, selectively inhibit the initiation and subsequent activation of rRNA synthesis. We then found that rapidly labeled heterogeneous mRNA-like RNA is synthesized in embryos at pre-MBT stage. We then performed cloning and expression studies of several genes, such as those for activin receptors, follistatin and aldolases, and then reached the studies of S-adenosylmethionine decarboxylase (SAMDC), a key enzyme in polyamine metabolism. Here, we cloned a Xenopus SAMDC cDNA and performed experiments to overexpress the in vitro-synthesized SAMDC mRNA in Xenopus early embryos, and found that the maternally preset program of apoptosis occurs in cleavage stage embryos, which is executed when embryos reach the stage of MBT. In the present article, we first summarize results on SAMDC and the maternal program of apoptosis, and then describe our studies on small-molecular-weight substances like polyamines, amino acids, and amines in Xenopus embryos. Finally, we summarize our studies on weak bases, especially on ammonium ion, as the specific inhibitor of ribosomal RNA synthesis in Xenopus embryonic cells.

Relationship between depolarization-induced force responses and Ca2+ content in skeletal muscle fibres of rat and toad.

PubMed

Owen, V J; Lamb, G D; Stephenson, D G; Fryer, M W

1997-02-01

1. The relationship between the total Ca2+ content of a muscle fibre and the magnitude of the force response to depolarization was examined in mechanically skinned fibres from the iliofibularis muscle of the toad and the extensor digitorum longus muscle of the rat. The response to depolarization in each skinned fibre was assessed either at the endogenous level of Ca2+ content or after depleting the fibre of Ca2+ to some degree. Ca2+ content was determined by a fibre lysing technique. 2. In both muscle types, the total Ca2+ content could be reduced from the endogenous level of approximately 1.3 mmol l-1 (expressed relative to intact fibre volume) to approximately 0.25 mmol l-1 by either depolarization or caffeine application in the presence of Ca2+ chelators, showing that the great majority of the Ca2+ was stored in the sarcoplasmic reticulum (SR). Chelation of Ca2+ in the transverse tubular (T-) system, either by exposure of fibres to EGTA before skinning or by permeabilizing the T-system with saponin after skinning, reduced the lower limit of Ca2+ content to < or = 0.12 mmol l-1, indicating that 10-20% of the total fibre Ca2+ resided in the T-system. 3. In toad fibres, both the peak and the area (i.e. time integral) of the force response to depolarization were reduced by any reduction in SR Ca2+ content, with both decreasing to zero in an approximately linear manner as the SR Ca2+ content was reduced to < 15% of the endogenous level. In rat fibres, the peak size of the force response was less affected by small decreases in SR content, but both the peak and area of the response decreased to zero with greater depletion. In partially depleted toad fibres, inhibition of SR Ca2+ uptake potentiated the force response to depolarization almost 2-fold. 4. The results show that in this skinned fibre preparation: (a) T-system depolarization and caffeine application can each virtually fully deplete the SR of Ca2+, irrespective of any putative inhibitory effect of SR depletion

Influence of altered gravity on brain cellular energy and plasma membrane metabolism of developing lower aquatic vertebrates

NASA Astrophysics Data System (ADS)

Slenzka, K.; Appel, R.; Kappel, Th.; Rahmann, H.

Biochemical analyses of the brain of cichlid fish larvae, exposed for 7 days to increased acceleration of 3g (hyper-g), revealed an increase in energy availability (succinate dehydrogenase activity, SDH), and in mitochondrial energy transformation (creatine kinase, Mi_a-CK), but no changes in an energy consumptive process (high-affinity Ca^2+-ATPase). Brain glucose-6-phosphate dehydrogenase (G6PDH) of developing fish was previously found to be increased after hyper-g exposure. Three respectively 5 hours thereafter dramatic fluctuations in enzyme activity were registered. Analysing the cytosolic or plasma membrane-located brain creatine kinase (BB-CK) of clawed toad larvae after long-term hyper-g exposure a significant increase in enzyme activity was demonstrated, whereas the activity of a high affinity Ca^2+-ATPase remained unaffected.

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

PubMed

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

2012-10-15

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

Two fast-type fibers in claw closer and abdominal deep muscles of the Australian freshwater crustacean, Cherax destructor, differ in Ca2+ sensitivity and troponin-I isoforms.

PubMed

Koenders, Annette; Lamey, Tina M; Medler, Scott; West, Jan M; Mykles, Donald L

2004-07-01

One type of fast fiber and two types of slow (slow-twitch, S1 and slow-tonic, S2) fibers are found in decapod crustacean skeletal muscles that differ in contractile properties and myofibrillar protein isoform compositions. In this study the structural characteristics, protein isoform compositions, and Ca2+-activation properties of fast fibers in the claw closer (F1) and abdominal deep flexor (F2) muscles of Cherax destructor were analyzed. For comparison, myofibrillar protein isoform compositions of slow (long-sarcomere) fibers from claw and abdomen were also determined; our results indicate that the slow fibers in the claw closer were the slow-twitch (S1) type and those in the abdominal superficial flexor were primarily slow-tonic (S2) type. F1 fibers had shorter resting sarcomere lengths (2.93 microm in unstretched fibers and 3.06 microm in stretched fibers) and smaller fiber diameter (256 microm) than F2 fibers (sarcomere lengths 3.48 microm in unstretched and 3.46 microm in stretched; 747 microm diameter). Moreover, F1 fibers showed a narrower range in sarcomere lengths than F2 fibers (2.81 to 3.28 microm vs. 2.47 to 4.05 micro m in unstretched fibers). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting showed that the fast fibers from claw and abdomen differed in troponin-I composition; F1 fibers expressed two isoforms of troponin-I (TnI1 and TnI2) in approximately equal amounts, whereas F2 fibers expressed primarily TnI3 and lower levels of TnI1. F1 fibers were more sensitive to Ca2+, as shown by higher pCa values at threshold activation (pCa(10)=6.50+/-0.07) and at 50% maximum force (pCa(50)=6.43+/-0.07) than F2 fibers (pCa(10)=6.12+/-0.04 and pCa(50)=5.88+/-0.03, respectively). F1 fibers also had a greater degree of co-operativity in Ca2+ activation, as shown by a higher maximum slope of the force-pCa curve (n(Ca)=12.98+/-2.27 vs. 4.34+/-0.64). These data indicate that there is a greater fast fiber-type diversity in crustacean

Alkaloids in bufonid toads (melanophryniscus): temporal and geographic determinants for two argentinian species.

PubMed

Daly, J W; Wilham, J M; Spande, T F; Garraffo, H M; Gil, R R; Silva, G L; Vaira, M

2007-04-01

Bufonid toads of the genus Melanophryniscus represent one of several lineages of anurans with the ability to sequester alkaloids from dietary arthropods for chemical defense. The alkaloid profile for Melanophryniscus stelzneri from a location in the province of Córdoba, Argentina, changed significantly over a 10-year period, probably indicating changes in availability of alkaloid-containing arthropods. A total of 29 alkaloids were identified in two collections of this population. Eight alkaloids were identified in M. stelzneri from another location in the province of Córdoba. The alkaloid profiles of Melanophryniscus rubriventris collected from four locations in the provinces of Salta and Jujuy, Argentina, contained 44 compounds and differed considerably between locations. Furthermore, alkaloid profiles of M. stelzneri and M. rubriventris strongly differed, probably reflecting differences in the ecosystem and hence in availability of alkaloid-containing arthropods.

Acute toxicity of arsenic and oxidative stress responses in the embryonic development of the common South American toad Rhinella arenarum.

PubMed

Mardirosian, Mariana Noelia; Lascano, Cecilia Inés; Ferrari, Ana; Bongiovanni, Guillermina Azucena; Venturino, Andrés

2015-05-01

Arsenic (As), a natural element of ecological relevance, is found in natural water sources throughout Argentina in concentrations between 0.01 mg/L and 15 mg/L. The autochthonous toad Rhinella arenarum was selected to study the acute toxicity of As and the biochemical responses elicited by the exposure to As in water during its embryonic development. The median lethal concentration (LC50) value averaged 24.3 mg/L As and remained constant along the embryonic development. However, As toxicity drastically decreased when embryos were exposed from heartbeat-stage on day 4 of development, suggesting the onset of detoxification mechanisms. Given the environmental concentrations of As in Argentina, there is a probability of exceeding lethal levels at 1% of sites. Arsenic at sublethal concentrations caused a significant decrease in the total antioxidant potential but generated an increase in endogenous glutathione (GSH) content and glutathione S-transferase (GST) activity. This protective response might prevent a deeper decline in the antioxidant system and further oxidative damage. Alternatively, it might be linked to As conjugation with GSH for its excretion. The authors conclude that toad embryos are more sensitive to As during early developmental stages and that relatively high concentrations of this toxic element are required to elicit mortality, but oxidative stress may be an adverse effect at sublethal concentrations. © 2014 SETAC.

The Impact of Nitinol Staples on the Compressive Forces, Contact Area, and Mechanical Properties in Comparison to a Claw Plate and Crossed Screws for the First Tarsometatarsal Arthrodesis.

PubMed

Aiyer, Amiethab; Russell, Nicholas A; Pelletier, Matthew H; Myerson, Mark; Walsh, William R

2016-06-01

Background The optimal fixation method for the first tarsometatarsal arthrodesis remains controversial. This study aimed to develop a reproducible first tarsometatarsal testing model to evaluate the biomechanical performance of different reconstruction techniques. Methods Crossed screws or a claw plate were compared with a single or double shape memory alloy staple configuration in 20 Sawbones models. Constructs were mechanically tested in 4-point bending to 1, 2, and 3 mm of plantar displacement. The joint contact force and area were measured at time zero, and following 1 and 2 mm of bending. Peak load, stiffness, and plantar gapping were determined. Results Both staple configurations induced a significantly greater contact force and area across the arthrodesis than the crossed screw and claw plate constructs at all measurements. The staple constructs completely recovered their plantar gapping following each test. The claw plate generated the least contact force and area at the joint interface and had significantly greater plantar gapping than all other constructs. The crossed screw constructs were significantly stiffer and had significantly less plantar gapping than the other constructs, but this gapping was not recoverable. Conclusions Crossed screw fixation provides a rigid arthrodesis with limited compression and contact footprint across the joint. Shape memory alloy staples afford dynamic fixation with sustained compression across the arthrodesis. A rigid polyurethane foam model provides an anatomically relevant comparison for evaluating the interface between different fixation techniques. Clinical Relevance The dynamic nature of shape memory alloy staples offers the potential to permit early weight bearing and could be a useful adjunctive device to impart compression across an arthrodesis of the first tarsometatarsal joint. Therapeutic, Level V: Bench testing. © 2015 The Author(s).

A decrease in heat insulation of the black-clawed brush-furred rat (Lophuromys melanonyx, Petter) during adaptation to high altitudes.

PubMed

Ivlev, Y F; Lavrenchenko, L A

2016-01-01

The results of the body-surface infrared thermography of rodents of the genus Lophuromys suggest that heat insulation of the black-clawed brush-furred rat L. melanonyx, a large specialized species of the AfroAlpine zone, is worse than that of the related smaller species, the golden-footed (L. chrysopus) and shorttailed (L. brevicaudus) brush-furred rats, that inhabit tropical forest and Erica shrub, respectively. A decrease in heat insulation of the alpine species may facilitate the use of solar radiation for supporting heat balance of these diurnal animals.

Effects of beta-escin and saponin on the transverse-tubular system and sarcoplasmic reticulum membranes of rat and toad skeletal muscle.

PubMed

Launikonis, B S; Stephenson, D G

1999-05-01

Mechanically skinned skeletal muscle fibres from rat and toad were exposed to the permeabilizing agents beta-escin and saponin. The effects of these agents on the sealed transverse tubular system (t-system) and sarcoplasmic reticulum (SR) were examined by looking at changes in the magnitude of the force responses to t-system depolarization, the time course of the fluorescence of fura-2 trapped in the sealed t-system, and changes in the magnitude of caffeine-induced contractures following SR loading with Ca2+ under defined conditions. In the presence of 2 microg ml-1 beta-escin and saponin, the response to t-system depolarization was not completely abolished, decreasing to a plateau, and a large proportion of fura-2 remained in the sealed t-system. At 10 microg ml-1, both agents abolished the ability of both rat and toad preparations to respond to t-system depolarization after 3 min of exposure, but a significant amount of fura-2 remained in sealed t-tubules even after exposure to 100 microg ml-1 beta-escin and saponin for 10 min. beta-Escin took longer than saponin to reduce the t-system depolarizations and fura-2 content of the sealed t-system to a similar level. The ability of the SR to load Ca2+ was reduced to a lower level after treatment with beta-escin than saponin. This direct effect on the SR occurred at much lower concentrations for rat (2 microg ml-1 beta-escin and 10 microg ml-1 saponin) than toad (10 microg ml-1 beta-escin and 150 microg ml-1 saponin). The reverse order in sensitivities to beta-escin and saponin of t-system and SR membranes indicates that the mechanisms of action of beta-escin and saponin are different in the two types of membrane. In conclusion, this study shows that: (1) beta-escin has a milder action on the surface membrane than saponin; (2) beta-escin is a more potent modifier of SR function; (3) simple permeabilization of membranes is not sufficient to explain the effects of beta-escin and saponin on muscle membranes; and (4) the t

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

PubMed

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

2008-06-01

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

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

PubMed

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

2014-12-01

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

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

PubMed Central

Easteal, Simon

1985-01-01

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

Relationship between depolarization-induced force responses and Ca2+ content in skeletal muscle fibres of rat and toad.

PubMed Central

Owen, V J; Lamb, G D; Stephenson, D G; Fryer, M W

1997-01-01

1. The relationship between the total Ca2+ content of a muscle fibre and the magnitude of the force response to depolarization was examined in mechanically skinned fibres from the iliofibularis muscle of the toad and the extensor digitorum longus muscle of the rat. The response to depolarization in each skinned fibre was assessed either at the endogenous level of Ca2+ content or after depleting the fibre of Ca2+ to some degree. Ca2+ content was determined by a fibre lysing technique. 2. In both muscle types, the total Ca2+ content could be reduced from the endogenous level of approximately 1.3 mmol l-1 (expressed relative to intact fibre volume) to approximately 0.25 mmol l-1 by either depolarization or caffeine application in the presence of Ca2+ chelators, showing that the great majority of the Ca2+ was stored in the sarcoplasmic reticulum (SR). Chelation of Ca2+ in the transverse tubular (T-) system, either by exposure of fibres to EGTA before skinning or by permeabilizing the T-system with saponin after skinning, reduced the lower limit of Ca2+ content to < or = 0.12 mmol l-1, indicating that 10-20% of the total fibre Ca2+ resided in the T-system. 3. In toad fibres, both the peak and the area (i.e. time integral) of the force response to depolarization were reduced by any reduction in SR Ca2+ content, with both decreasing to zero in an approximately linear manner as the SR Ca2+ content was reduced to < 15% of the endogenous level. In rat fibres, the peak size of the force response was less affected by small decreases in SR content, but both the peak and area of the response decreased to zero with greater depletion. In partially depleted toad fibres, inhibition of SR Ca2+ uptake potentiated the force response to depolarization almost 2-fold. 4. The results show that in this skinned fibre preparation: (a) T-system depolarization and caffeine application can each virtually fully deplete the SR of Ca2+, irrespective of any putative inhibitory effect of SR depletion

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

USGS Publications Warehouse

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

2015-01-01

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

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

USGS Publications Warehouse

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

2004-01-01

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

Flightless I Expression Enhances Murine Claw Regeneration Following Digit Amputation.

PubMed

Strudwick, Xanthe L; Waters, James M; Cowin, Allison J

2017-01-01

The mammalian digit tip is capable of both reparative and regenerative wound healing dependent on the level of amputation injury. Removal of the distal third of the terminal phalange results in successful regeneration, whereas a more severe, proximal, amputation heals by tissue repair. Flightless I (Flii) is involved in both tissue repair and regeneration. It negatively regulates wound repair but elicits a positive effect in hair follicle regeneration, with Flii overexpression resulting in significantly longer hair fibers. Using a model of digit amputation in Flii overexpressing (FIT) mice, we investigated Flii in digit regeneration. Both wild-type and FIT digits regenerated after distal amputation with newly regenerated FIT claws being significantly longer than intact controls. No regeneration was observed in wild-type mice after severe proximal amputation; however, FIT mice showed significant regeneration of the missing digit. Using a three-dimensional model of nail formation, connective tissue fibroblasts isolated from the mesenchymal tissue surrounding the wild-type and FIT digit tips and cocultured with skin keratinocytes demonstrated aggregate structures resembling rudimentary nail buds only when Flii was overexpressed. Moreover, β-catenin and cyclin D1 expression was maintained in the FIT regenerating germinal matrix suggesting a potential interaction of Flii with Wnt signaling during regeneration. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

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

PubMed

Hakim, J; Gipouloux, J D

1975-10-27

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

A review of the biology and literature of the Gulf Coast Toad (Incilius nebulifer), native to Mexico and the United States.

PubMed

Mendelson, Joseph R Iii; Kinsey, Chase T; Murphy, James B

2015-06-24

The Gulf Coast Toad (Incilius nebulifer) is an abundant and widespread species within its range in the United States and Mexico, so it appears on many faunal checklists and is considered in diverse kinds of research. We review the basic biology, distribution, and published history of this species, identifying only those records and publications referable to I. nebulifer, to help researchers identify published works pertaining to I. nebulfer rather than I. valliceps, with which it formerly was considered to be conspecific.

Vortex Formation and Foraging in Polyphenic Spadefoot Toad Tadpoles.

PubMed

Bazazi, Sepideh; Pfennig, Karin S; Handegard, Nils Olav; Couzin, Iain D

2012-06-01

Animal aggregations are widespread in nature and can exhibit complex emergent properties not found at an individual level. We investigate one such example here, collective vortex formation by congeneric spadefoot toad tadpoles: Spea bombifrons and S. multiplicata. Tadpoles of these species develop into either an omnivorous or a carnivorous (cannibalistic) morph depending on diet. Previous studies show S. multiplicata are more likely to develop into omnivores and feed on suspended organic matter in the water body. The omnivorous morph is frequently social, forming aggregates that move and forage together, and form vortices in which they adopt a distinctive slowly-rotating circular formation. This behaviour has been speculated to act as a means to agitate the substratum in ponds and thus could be a collective foraging strategy. Here we perform a quantitative investigation of the behaviour of tadpoles within aggregates. We found that only S. multiplicata groups exhibited vortex formation, suggesting that social interactions differ between species. The probability of collectively forming a vortex, in response to introduced food particles, increased for higher tadpole densities and when tadpoles were hungry. Individuals inside a vortex moved faster and exhibited higher (by approximately 27%) tailbeat frequencies than those outside the vortex, thus incurring a personal energetic cost. The resulting environmental modification, however, suggests vortex behaviour may be an adaptation to actively create, and exploit, a resource patch within the environment.

Evaluation of inorganic elements in cat's claw teas using ICP OES and GF AAS.

PubMed

Pereira, João B; Dantas, Kelly G F

2016-04-01

The determination of Ba, Ca, Cu, Fe, Mg, Mn, P, Pb, and Zn by inductively coupled plasma optical emission spectrometry (ICP OES), and Se by graphite furnace atomic absorption spectrometry (GF AAS), has been carried out in dry matter and teas from 11 samples of the cat's claw plant. The accuracy and precision values were verified against GBW 07604 (Poplar leaves) certified reference material and by the recovery test. Results showed a high content of Ca in the medicinal plant studied, followed by Mg and P. The values obtained showed that the elements studied have different concentrations depending on the method of tea preparation. The highest levels were observed in Ca and Mg, and the lowest for Se and Pb, by both infusion and decoction. Teas prepared from this plant were found to be at safe levels for human consumption, and may be suitable as sources of these elements in the human diet. Copyright © 2015 Elsevier Ltd. All rights reserved.

An Efficient Strategy Based on Liquid-Liquid Extraction with Three-Phase Solvent System and High Speed Counter-Current Chromatography for Rapid Enrichment and Separation of Epimers of Minor Bufadienolide from Toad Meat.

PubMed

Zou, Denglang; Zhu, Xuelin; Zhang, Fan; Du, Yurong; Ma, Jianbin; Jiang, Renwang

2018-01-31

This study presents an efficient strategy based on liquid-liquid extraction with three-phase solvent system and high speed counter-current chromatography for rapid enrichment and separation of epimers of minor bufadienolide from toad meat. The reflux extraction conditions were optimized by response surface methodology first, and a novel three-phase solvent system composed of n-hexane/methyl acetate/acetonitrile/water (3:6:5:5, v/v) was developed for liquid-liquid extraction of the crude extract. This integrative extraction process could enrich minor bufadienolide from complex matrix efficiently and minimize the loss of minor targets induced by repeated extraction with different kinds of organic solvents occurring in the classical liquid two-phase extraction. As a result, four epimers of minor bufadienolide were greatly enriched in the middle phase and total content of these epimers of minor bufadienolide was increased from 3.25% to 46.23%. Then, the enriched four epimers were separated by HSCCC with a two-phase solvent system composed of chloroform/methanol/water (4:2:2, v/v) successfully. Furthermore, we tested Na + ,K + -ATPase (NKA) inhibitory effect of the four epimers. 3β-Isomers of bufadienolide showed stronger (>8-fold) inhibitory activity than 3α-isomers. The characterization of minor bufadienolide in toad meat and their significant difference of inhibitory effect on NKA would promote the further quantitative analysis and safety evaluation of toad meat as a food source.

Our Zoo to You

ERIC Educational Resources Information Center

Wickless, Mimi; Brooks, David W.; Abuloum, Amjad; Mancuso, Brian; Heng-Moss, Tiffany M.; Mayo, Lois

2003-01-01

An innovative zoo outreach program, Our Zoo to You, places zoo animals in local classrooms for extended observation periods. With guidance and support from zoo staff, students are able to safely experience a variety of animals, including geckos, snakes, legless lizards, horned toads, ringneck doves, ferrets, hedgehogs, African brown millipedes,…

Higher thyroid hormone receptor expression correlates with short larval periods in spadefoot toads and increases metamorphic rate

PubMed Central

Hollar, Amy R.; Choi, Jinyoung; Grimm, Adam T.; Buchholz, Daniel R.

2011-01-01

Spadefoot toad species display extreme variation in larval period duration, due in part to evolution of thyroid hormone (TH) physiology. Specifically, desert species with short larval periods have higher tail tissue content of TH and exhibit increased responsiveness to TH. To address the molecular basis of larval period differences, we examined TH receptor (TR) expression across species. Based on the dual function model for the role of TR in development, we hypothesized that desert spadefoot species with short larval periods would have 1) late onset of TR expression prior to the production of endogenous TH and 2) higher TR levels when endogenous TH becomes available. To test these hypotheses, we cloned fragments of TRα and TRβ genes from the desert spadefoot toads Scaphiopus couchii and Spea multiplicata and their non-desert relative Pelobates cultripes and measured their mRNA levels in tails using quantitative PCR in the absence (premetamorphosis) or presence (natural metamorphosis) of TH. All species express TRα and TRβ from the earliest stages measured (from just after hatching), but S. couchii, which has the shortest larval period, had more TRα throughout development compared to P. cultripes, which has the longest larval period. TRβ mRNA levels were similar across species. Exogenous T3 treatment induced faster TH-response gene expression kinetics in S. couchii compared to the other species, consistent with its increased TRα mRNA expression and indicative of a functional consequence of more TRα activity at the molecular level. To directly test whether higher TRα expression may contribute to shorter larval periods, we overexpressed TRα via plasmid injection into tail muscle cells of the model frog Xenopus laevis and found an increased rate of muscle cell death in response to TH. These results suggest that increased TRα expression evolved in S. couchii and contribute to its higher metamorphic rates. PMID:21651912

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

PubMed Central

Anchukaitis, Kevin J.; Evans, Michael N.

2010-01-01

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

THE EFFECT OF SMOOTH MUSCLE ON THE INTERCELLULAR SPACES IN TOAD URINARY BLADDER

PubMed Central

DiBona, Donald R.; Civan, Mortimer M.

1970-01-01

Phase microscopy of toad urinary bladder has demonstrated that vasopressin can cause an enlargement of the epithelial intercellular spaces under conditions of no net transfer of water or sodium. The suggestion that this phenomenon is linked to the hormone's action as a smooth muscle relaxant has been tested and verified with the use of other agents effecting smooth muscle: atropine and adenine compounds (relaxants), K+ and acetylcholine (contractants). Furthermore, it was possible to reduce the size and number of intercellular spaces, relative to a control, while increasing the rate of osmotic water flow. A method for quantifying these results has been developed and shows that they are, indeed, significant. It is concluded, therefore, that the configuration of intercellular spaces is not a reliable index of water flow across this epithelium and that such a morphologic-physiologic relationship is tenuous in any epithelium supported by a submucosa rich in smooth muscle. PMID:4915450

Social partner discrimination based on sounds and scents in Asian small-clawed otters ( Aonyx cinereus)

NASA Astrophysics Data System (ADS)

Lemasson, A.; Mikus, M.-A.; Blois-Heulin, C.; Lodé, T.

2013-03-01

Ability to discriminate familiar conspecifics is an essential competence in any group-living species, ensuring socio-spatial cohesion, but in many animals, such as mustelids, the relative importance of the different communicative modalities for discrimination is poorly understood. In otters, there is evidence of intra-specific variation in physical appearance and in feces chemical profile, but the potential for acoustic identity coding as well as for identity decoding in visual, acoustic and olfactive domains remains unexplored. We investigated the acoustic structure of contact calls in five captive groups of small-clawed otters and found that it is possible to reliably assign one particular call to a given adult male caller. Females discriminated between familiar and unfamiliar adult males based on their sound (playback) and smell (feces) but not based on their picture, suggesting abilities to memorize and use acoustic and olfactive signatures in their daily social life.

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

PubMed

Martin, D S; Desser, S S

1991-01-01

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

Br-rich tips of calcified crab claws are less hard but more fracture resistant: a comparison of biomineralized and heavy-element biomaterials

PubMed Central

Schofield, Robert M. S.; Niedbala, Jack C.; Nesson, Michael H.; Tao, Ye; Shokes, Jacob E.; Scott, Robert A.; Latimer, Matthew J.

2009-01-01

We find that the spoon-like tips of the chelipeds (large claws) of the crab Pachygrapsus crassipes differ from the rest of the claw in that they are not calcified, but instead contain about 1% bromine – thus they represent a new example of a class of structural biomaterials that contain heavy elements such as Zn, Mn, Fe, Cu, and Br bound in an organic matrix. X-ray absorption spectroscopy data suggest that the bromine is bound to phenyl rings, possibly in tyrosine. We measure a broad array of mechanical properties of a heavy-element biomaterial (abrasion resistance, coefficient of kinetic friction, energy of fracture, hardness, modulus of elasticity and dynamic mechanical properties) for the first time, and we make a direct comparison with a mineralized tissue. Our results suggest that the greatest advantage of bromine-rich cuticle over calcified cuticle is resistance to fracture (the energy of fracture is about an order of magnitude greater than for calcified cuticle). The greatest advantage relative to unenriched cuticle, represented by ant mandible cuticle, is a factor of about 1.5 greater hardness and modulus of elasticity. The spoon-like tips gain increased fracture resistance from the orientation of the constituent laminae and from the viscoelasticity of the materials. We suggest that fracture resistance is of greater importance in smaller organisms, and we speculate that one function of heavy elements in mechanical biomaterials is to reduce molecular resonant frequencies and thereby increase absorption of energy from impacts. PMID:19422071

Fluoride bioaccumulation and toxic effects on the survival and behavior of the endangered white-clawed crayfish Austropotamobius pallipes (Lereboullet).

PubMed

Aguirre-Sierra, Arantxa; Alonso, Alvaro; Camargo, Julio A

2013-08-01

Laboratory experiments were performed to examine the toxic effects of fluoride (F(-)) on the survival and behavior of white-clawed crayfish (Austropotamobius pallipes). Body fluoride contents (bioaccumulation) of test crayfish were also examined. No significant differences between male and female crayfish regarding mortality, escape (tail-flip) response, and fluoride bioaccumulation were detected. For mortality, 48-, 72-, 96-, 120-, 144-, 168-, and 192-h median lethal concentrations (LC50) were estimated to be 93.0, 55.3, 42.7, 36.5, 32.9, 30.6, and 28.9 mg F(-)/l, respectively. For the escape response, 48-, 72-, 96-, 120-, 144-, 168- and 192-h median effective concentrations (EC50) were estimated to be 18.4, 11.1, 8.6, 7.4, 6.7, 6.2 and 5.9 mg F(-)/l, respectively. Average food consumption in test crayfish tended to decrease with increasing water fluoride concentration with a 192-h lowest-observed effect concentration of 10.7 mg F(-)/l. These results indicate that the escape response was the most sensitive end point to fluoride toxicity followed by food consumption and mortality. Fluoride bioaccumulation in test crayfish increased with increasing water fluoride concentration and exposure time. The exoskeleton accumulated more fluoride than muscle. A comparison of the obtained results with previous data for other freshwater invertebrates shows that white-clawed crayfish are relatively tolerant to fluoride toxicity. We conclude that fluoride pollution in freshwater ecosystems should not be viewed as an important risk factor contributing to the catastrophic decrease of A. pallipes in many European countries. Our results indicate that fluoride bioaccumulation in A. pallipes might be used as a bioindicator of fluoride pollution in freshwater ecosystems where it is present.

Questionnaire survey of the pan-African trade in lion body parts

PubMed Central

Loveridge, Andrew J.; Newton, David J.; Macdonald, David W.

2017-01-01

The African lion is in decline across its range, and consumptive utilisation and trade of their body parts and skins has been postulated as a cause for concern. We undertook a pan-African questionnaire and literature survey to document informed opinion and evidence for the occurrence of domestic and international trade and consumption in African lion body parts across current and former range states. Sixty-five people from 18 countries participated in the online questionnaire survey (run from July 2014 to May 2015), with information provided for 28 countries (including 20 out of 24 countries believed to have extant populations). Respondents were experts within their professional spheres, and 77% had ≥6 years relevant experience within lion conservation or allied wildlife matters. Their opinions revealed wide sub-regional differences in consumptive use, drivers of trade, and access to lions that impact wild lion populations in different ways. Traditional medicine practices (African and Asian) were perceived to be the main uses to which lion body parts and bones are put domestically and traded internationally, and there is reason for concern about persistent imports from former lion range states (mainly in West Africa) for parts for this purpose. The domestic, rather than international, trade in lion body parts was perceived to be a bigger threat to wild lion populations. Parts such as skin, claws, teeth and bones are thought to be in most demand across the continent. The impact of international trade on wild populations was acknowledged to be largely unknown, but occasionally was judged to be ‘high’, and therefore vigilance is needed to monitor emerging detrimental impacts. Seventeen countries were nominated as priorities for immediate monitoring, including: South Africa, Tanzania, Zimbabwe, Mozambique, Zambia, Botswana, Kenya, Nigeria, and Cameroon. Reasons for their selection include: prevalence of trophy hunting, ‘hot spots’ for poaching, active

Questionnaire survey of the pan-African trade in lion body parts.

PubMed

Williams, Vivienne L; Loveridge, Andrew J; Newton, David J; Macdonald, David W

2017-01-01

The African lion is in decline across its range, and consumptive utilisation and trade of their body parts and skins has been postulated as a cause for concern. We undertook a pan-African questionnaire and literature survey to document informed opinion and evidence for the occurrence of domestic and international trade and consumption in African lion body parts across current and former range states. Sixty-five people from 18 countries participated in the online questionnaire survey (run from July 2014 to May 2015), with information provided for 28 countries (including 20 out of 24 countries believed to have extant populations). Respondents were experts within their professional spheres, and 77% had ≥6 years relevant experience within lion conservation or allied wildlife matters. Their opinions revealed wide sub-regional differences in consumptive use, drivers of trade, and access to lions that impact wild lion populations in different ways. Traditional medicine practices (African and Asian) were perceived to be the main uses to which lion body parts and bones are put domestically and traded internationally, and there is reason for concern about persistent imports from former lion range states (mainly in West Africa) for parts for this purpose. The domestic, rather than international, trade in lion body parts was perceived to be a bigger threat to wild lion populations. Parts such as skin, claws, teeth and bones are thought to be in most demand across the continent. The impact of international trade on wild populations was acknowledged to be largely unknown, but occasionally was judged to be 'high', and therefore vigilance is needed to monitor emerging detrimental impacts. Seventeen countries were nominated as priorities for immediate monitoring, including: South Africa, Tanzania, Zimbabwe, Mozambique, Zambia, Botswana, Kenya, Nigeria, and Cameroon. Reasons for their selection include: prevalence of trophy hunting, 'hot spots' for poaching, active domestic trade

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

PubMed

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

1992-01-01

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

The effect of claw horn disruption lesions and body condition score at dry-off on survivability, reproductive performance, and milk production in the subsequent lactation.

PubMed

Machado, V S; Caixeta, L S; McArt, J A A; Bicalho, R C

2010-09-01

The objective of this study was to evaluate the effects of claw horn disruption lesions (CHDL; sole ulcers and white line disease) and body condition score (BCS) at dry-off on survivability, milk production, and reproductive performance during the subsequent lactation. An observational prospective cohort study was conducted on a large commercial dairy in Cayuga County, New York, from September 2008 until January 2009. A total of 573 cows enrolled at dry-off were scored for body condition and hoof trimmed; digits were visually inspected for the presence of CHDL. The BCS data were recategorized into a 3-level variable BCS group (BCSG), with cows with BCS<3 placed in BCSG 1 (n=113), cows with BCS=3 placed in BCSG 2 (n=254), and cows with BCS>3 placed in BCSG 3 (n=206). Cows in BCSG 2 were 1.35 and 1.02 times more likely to conceive than cows in BCSG 1 and 3, respectively. The cull/death hazard for BCSG 1 cows was 1.55 and 1.47 times higher than for cows in BCSG 2 and BCSG 3, respectively. Milk yield for cows in BCSG 2 (44.6 kg/d, 95% CI 43.4-45.8) was significantly greater than that for cows in BCSG 1 (41.5 kg/d, 95% CI 39.8-43.3). Cows with previous lactation days open14,054 kg had a similar 1.6 times higher odds of being classified into BCSG 1. Claw horn disruption lesions were found in 24.4% of the cows (n=140) at dry-off. Cows without CHDL were 1.4 times more likely to conceive than cows with CHDL. Additionally, lesion cows were 1.7 times more likely to die or be culled than nonlesion cows. Absence of CHDL did not have a significant effect on milk yield. These findings highlight the importance of claw health and BCS at the end of lactation on future survival and performance. Copyright (c) 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

African and Non-African Admixture Components in African Americans and An African Caribbean Population

PubMed Central

Murray, Tanda; Beaty, Terri H.; Mathias, Rasika A.; Rafaels, Nicholas; Grant, Audrey Virginia; Faruque, Mezbah U.; Watson, Harold R.; Ruczinski, Ingo; Dunston, Georgia M.; Barnes, Kathleen C.

2013-01-01

Admixture is a potential source of confounding in genetic association studies, so it becomes important to detect and estimate admixture in a sample of unrelated individuals. Populations of African descent in the US and the Caribbean share similar historical backgrounds but the distributions of African admixture may differ. We selected 416 ancestry informative markers (AIMs) to estimate and compare admixture proportions using STRUCTURE in 906 unrelated African Americans (AAs) and 294 Barbadians (ACs) from a study of asthma. This analysis showed AAs on average were 72.5% African, 19.6% European and 8% Asian, while ACs were 77.4% African, 15.9% European, and 6.7% Asian which were significantly different. A principal components analysis based on these AIMs yielded one primary eigenvector that explained 54.04% of the variation and captured a gradient from West African to European admixture. This principal component was highly correlated with African vs. European ancestry as estimated by STRUCTURE (r2 = 0.992, r2 = 0.912, respectively). To investigate other African contributions to African American and Barbadian admixture, we performed PCA on ~14,000 (14k) genome-wide SNPs in AAs, ACs, Yorubans, Luhya and Maasai African groups, and estimated genetic distances (FST). We found AAs and ACs were closest genetically (FST = 0.008), and both were closer to the Yorubans than the other East African populations. In our sample of individuals of African descent, ~400 well-defined AIMs were just as good for detecting substructure as ~14,000 random SNPs drawn from a genome-wide panel of markers. PMID:20717976

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

PubMed

Dos Santos, Viviane Gularte Tavares; Amato, Suzana B; Borges-Martins, Márcio

2013-03-01

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.

Br-rich tips of calcified crab claws are less hard but more fracture resistant: a comparison of mineralized and heavy-element biological materials.

PubMed

Schofield, Robert M S; Niedbala, Jack C; Nesson, Michael H; Tao, Ye; Shokes, Jacob E; Scott, Robert A; Latimer, Matthew J

2009-06-01

We find that the spoon-like tips of the chelipeds (large claws) of the crab Pachygrapsus crassipes differ from the rest of the claw in that they are not calcified, but instead contain about 1% bromine--thus they represent a new example of a class of structural biological materials that contain heavy elements such as Zn, Mn, Fe, Cu, and Br bound in an organic matrix. X-ray absorption spectroscopy data suggest that the bromine is bound to phenyl rings, possibly in tyrosine. We measure a broad array of mechanical properties of a heavy-element biological material for the first time (abrasion resistance, coefficient of kinetic friction, energy of fracture, hardness, modulus of elasticity and dynamic mechanical properties), and we make a direct comparison with a mineralized tissue. Our results suggest that the greatest advantage of bromine-rich cuticle over calcified cuticle is resistance to fracture (the energy of fracture is about an order of magnitude greater than for calcified cuticle). The greatest advantage relative to unenriched cuticle, represented by ant mandible cuticle, is a factor of about 1.5 greater hardness and modulus of elasticity.The spoon-like tips gain additional fracture resistance from the orientation of the constituent laminae and from the viscoelasticity of the material. We suggest that fracture resistance is of greater importance in smaller organisms, and we speculate that one function of heavy elements in structural biological materials is to reduce molecular resonant frequencies and thereby increase absorption of energy from impacts.

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

PubMed

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

2016-01-01

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

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

PubMed

Kouba, Andrew J; delBarco-Trillo, Javier; Vance, Carrie K; Milam, Callie; Carr, Meghan

2012-08-20

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. 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. 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 < 0.05), the 300 IU hCG treatment group had a much higher average sperm concentration (P < 0.05) than the treatment group receiving 4.0 micrograms LHRH. In contrast, these two treatments did not result in significant differences in sperm motility or quality of forward progressive motility. However, more males went into amplexus when treated with LHRH vs. hCG (90% vs. 75%) by nine hours post-administration. There is a clear dichotomy between the two hormones

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

PubMed

Narayan, Edward J; Hero, Jean-Marc

2014-04-01

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

Interactive effects of mechano- and chemo-receptor inputs on cardiorespiratory outputs in the toad.

PubMed

Wang, T; Taylor, E W; Reid, S G; Milsom, W K

2004-04-20

Arterial blood pressure (P(b)), pulmocutaneous blood flow (Q(pc)), heart rate (f(H)), and fictive ventilation (motor activity in the Vth cranial nerve, V(int)), were recorded from decerebrated, paralysed toads receiving unidirectional ventilation with experimental gas mixtures over a range of lung inflation. At the onset of spontaneous bouts of fictive ventilation, (Q(pc)) and P(b) increased immediately, often with changes in heart rate, implying central cardiorespiratory interactions. Inflation of the lungs with different gas mixtures revealed that the effect of hypercarbia on V(int) was reduced by lung inflation and that feedback from pulmonary stretch receptors may summate with central feedforward control of f(H) and (Q(pc)) in an interactive fashion. The results of bolus injections of cyanide into the carotid or the pulmonary circulations suggest there are oxygen sensitive receptors in both circuits that affect the cardiovascular system directly and respiratory activity by complex central interactions with inputs from central chemoreceptors and pulmonary stretch receptors.

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

NASA Astrophysics Data System (ADS)

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

2016-04-01

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

Checklist and Simple Identification Key for Frogs and Toads from District IV of The MADA Scheme, Kedah, Malaysia

PubMed Central

Jaafar, Ibrahim; Chai, Teoh Chia; Sah, Shahrul Anuar Mohd; Akil, Mohd Abdul Muin Md.

2009-01-01

A survey was conducted to catalogue the diversity of anurans in District IV of the Muda Agriculture Development Authority Scheme (MADA) in Kedah Darul Aman, Malaysia, from July 1996 to January 1997. Eight species of anurans from three families were present in the study area. Of these, the Common Grass Frog (Fejevarya limnocharis) was the most abundant, followed by Mangrove Frog (Fejevarya cancrivora), Long-legged Frog (Hylarana macrodactyla), and Common Toad (Duttaphrynus melanostictus). Puddle Frog (Occidozyga lima), Taiwanese Giant Frog (Hoplobatrachus rugulosus), and Banded Bullfrog (Kaluola pulchra) were rare during the sampling period, and only one Paddy Frog (Hylarana erythraea) was captured. A simple identification key for the anurans of this area is included for use by scientists and laymen alike. PMID:24575178

A multilocus perspective on the speciation history of a North American aridland toad (Anaxyrus punctatus).

PubMed

Bryson, Robert W; Jaeger, Jef R; Lemos-Espinal, Julio A; Lazcano, David

2012-09-01

Interpretations of phylogeographic patterns can change when analyses shift from single gene-tree to multilocus coalescent analyses. Using multilocus coalescent approaches, a species tree and divergence times can be estimated from a set of gene trees while accounting for gene-tree stochasticity. We utilized the conceptual strengths of a multilocus coalescent approach coupled with complete range-wide sampling to examine the speciation history of a broadly distributed, North American warm-desert toad, Anaxyrus punctatus. Phylogenetic analyses provided strong support for three major lineages within A. punctatus. Each lineage broadly corresponded to one of three desert regions. Early speciation in A. punctatus appeared linked to late Miocene-Pliocene development of the Baja California peninsula. This event was likely followed by a Pleistocene divergence associated with the separation of the Chihuahuan and Sonoran Deserts. Our multilocus coalescent-based reconstruction provides an informative contrast to previous single gene-tree estimates of the evolutionary history of A. punctatus. Copyright © 2012 Elsevier Inc. All rights reserved.

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

PubMed

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

2011-10-15

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

Vocal classification of vocalizations of a pair of Asian small-clawed otters to determine stress.

PubMed

Scheifele, Peter M; Johnson, Michael T; Fry, Michelle; Hamel, Benjamin; Laclede, Kathryn

2015-07-01

Asian Small-Clawed Otters (Aonyx cinerea) are a small, protected but threatened species living in freshwater. They are gregarious and live in monogamous pairs for their lifetimes, communicating via scent and acoustic vocalizations. This study utilized a hidden Markov model (HMM) to classify stress versus non-stress calls from a sibling pair under professional care. Vocalizations were expertly annotated by keepers into seven contextual categories. Four of these-aggression, separation anxiety, pain, and prefeeding-were identified as stressful contexts, and three of them-feeding, training, and play-were identified as non-stressful contexts. The vocalizations were segmented, manually categorized into broad vocal type call types, and analyzed to determine signal to noise ratios. From this information, vocalizations from the most common contextual categories were used to implement HMM-based automatic classification experiments, which included individual identification, stress vs non-stress, and individual context classification. Results indicate that both individual identity and stress vs non-stress were distinguishable, with accuracies above 90%, but that individual contexts within the stress category were not easily separable.

A torque estimator for a traveling wave ultrasonic motor--application to an active claw.

PubMed

Giraud, Frédéric; Semail, Betty

2006-08-01

Depending on its electrical-to-mechanical energy conversion process, the torque on a traveling wave ultrasonic motor (TWUM)'s shaft is not directly proportional to a measurable electrical variable, such as current or voltage. But it is derived from a complicated process at the stator/rotor interface. The load torque is thus quite unknown, and this can be a disadvantage in applications in which a torque limitation is required or a torque measurement is needed. The aim of this article is to come up with a straightforward torque estimator on a TWUM. For that purpose, the motor is modeled; this modeling leads to different estimator strategies. More specifically, we chose a strategy for which a speed sensor is useless, relying only on the stator's resonant behavior. The parameters of the motor needed for the estimator are measured afterward, and some nonlinearities are identified and taken into account. Several experimental trials then are carried out to check the performance of the estimator. A claw actuated by a TWUM is presented because this is a typical application in which the knowledge of the torque helps guarantee the safety of the device.

Characterization of a Crabs Claw Gene in basal eudicot species Epimedium sagittatum (Berberidaceae).

PubMed

Sun, Wei; Huang, Wenjun; Li, Zhineng; Lv, Haiyan; Huang, Hongwen; Wang, Ying

2013-01-08

The Crabs Claw (CRC) YABBY gene is required for regulating carpel development in angiosperms and has played an important role in nectary evolution during core eudicot speciation. The function or expression of CRC-like genes has been explored in two basal eudicots, Eschscholzia californica and Aquilegia formosa. To further investigate the function of CRC orthologous genes related to evolution of carpel and nectary development in basal eudicots, a CRC ortholog, EsCRC, was isolated and characterized from Epimedium sagittatum (Sieb. and Zucc.) Maxim. A phylogenetic analysis of EsCRC and previously identified CRC-like genes placed EsCRC within the basal eudicot lineage. Gene expression results suggest that EsCRC is involved in the development of sepals and carpels, but not nectaries. Phenotypic complementation of the Arabidopsis mutant crc-1 was achieved by constitutive expression of EsCRC. In addition, over-expression of EsCRC in Arabidopsis and tobacco gave rise to abaxially curled leaves. Transgenic results together with the gene expression analysis suggest that EsCRC may maintain a conserved function in carpel development and also play a novel role related to sepal formation. Absence of EsCRC and ElCRC expression in nectaries further indicates that nectary development in non-core eudicots is unrelated to expression of CRC-like genes.

Characterization of a Crabs Claw Gene in Basal Eudicot Species Epimedium sagittatum (Berberidaceae)

PubMed Central

Sun, Wei; Huang, Wenjun; Li, Zhineng; Lv, Haiyan; Huang, Hongwen; Wang, Ying

2013-01-01

The Crabs Claw (CRC) YABBY gene is required for regulating carpel development in angiosperms and has played an important role in nectary evolution during core eudicot speciation. The function or expression of CRC-like genes has been explored in two basal eudicots, Eschscholzia californica and Aquilegia formosa. To further investigate the function of CRC orthologous genes related to evolution of carpel and nectary development in basal eudicots, a CRC ortholog, EsCRC, was isolated and characterized from Epimedium sagittatum (Sieb. and Zucc.) Maxim. A phylogenetic analysis of EsCRC and previously identified CRC-like genes placed EsCRC within the basal eudicot lineage. Gene expression results suggest that EsCRC is involved in the development of sepals and carpels, but not nectaries. Phenotypic complementation of the Arabidopsis mutant crc-1 was achieved by constitutive expression of EsCRC. In addition, over-expression of EsCRC in Arabidopsis and tobacco gave rise to abaxially curled leaves. Transgenic results together with the gene expression analysis suggest that EsCRC may maintain a conserved function in carpel development and also play a novel role related to sepal formation. Absence of EsCRC and ElCRC expression in nectaries further indicates that nectary development in non-core eudicots is unrelated to expression of CRC-like genes. PMID:23299438

Alteration of Neutrophil Reactive Oxygen Species Production by Extracts of Devil's Claw (Harpagophytum).

PubMed

Muzila, Mbaki; Rumpunen, Kimmo; Wright, Helen; Roberts, Helen; Grant, Melissa; Nybom, Hilde; Sehic, Jasna; Ekholm, Anders; Widén, Cecilia

2016-01-01

Harpagophytum, Devil's Claw, is a genus of tuberiferous xerophytic plants native to southern Africa. Some of the taxa are appreciated for their medicinal effects and have been traditionally used to relieve symptoms of inflammation. The objectives of this pilot study were to investigate the antioxidant capacity and the content of total phenols, verbascoside, isoverbascoside, and selected iridoids, as well as to investigate the capacity of various Harpagophytum taxa in suppressing respiratory burst in terms of reactive oxygen species produced by human neutrophils challenged with phorbol myristate acetate (PMA), opsonised Staphylococcus aureus, and Fusobacterium nucleatum. Harpagophytum plants were classified into different taxa according to morphology, and DNA analysis was used to confirm the classification. A putative new variety of H. procumbens showed the highest degree of antioxidative capacity. Using PMA, three Harpagophytum taxa showed anti-inflammatory effects with regard to the PBS control. A putative hybrid between H. procumbens and H. zeyheri in contrast showed proinflammatory effect on the response of neutrophils to F. nucleatum in comparison with treatment with vehicle control. Harpagophytum taxa were biochemically very variable and the response in suppressing respiratory burst differed. Further studies with larger number of subjects are needed to corroborate anti-inflammatory effects of different taxa of Harpagophytum.

Alteration of Neutrophil Reactive Oxygen Species Production by Extracts of Devil's Claw (Harpagophytum)

PubMed Central

Muzila, Mbaki; Wright, Helen; Roberts, Helen; Grant, Melissa; Nybom, Hilde; Sehic, Jasna; Ekholm, Anders

2016-01-01

Harpagophytum, Devil's Claw, is a genus of tuberiferous xerophytic plants native to southern Africa. Some of the taxa are appreciated for their medicinal effects and have been traditionally used to relieve symptoms of inflammation. The objectives of this pilot study were to investigate the antioxidant capacity and the content of total phenols, verbascoside, isoverbascoside, and selected iridoids, as well as to investigate the capacity of various Harpagophytum taxa in suppressing respiratory burst in terms of reactive oxygen species produced by human neutrophils challenged with phorbol myristate acetate (PMA), opsonised Staphylococcus aureus, and Fusobacterium nucleatum. Harpagophytum plants were classified into different taxa according to morphology, and DNA analysis was used to confirm the classification. A putative new variety of H. procumbens showed the highest degree of antioxidative capacity. Using PMA, three Harpagophytum taxa showed anti-inflammatory effects with regard to the PBS control. A putative hybrid between H. procumbens and H. zeyheri in contrast showed proinflammatory effect on the response of neutrophils to F. nucleatum in comparison with treatment with vehicle control. Harpagophytum taxa were biochemically very variable and the response in suppressing respiratory burst differed. Further studies with larger number of subjects are needed to corroborate anti-inflammatory effects of different taxa of Harpagophytum. PMID:27429708

The genome sequence of the emerging common midwife toad virus identifies an evolutionary intermediate within ranaviruses.

PubMed

Mavian, Carla; López-Bueno, Alberto; Balseiro, Ana; Casais, Rosa; Alcamí, Antonio; Alejo, Alí

2012-04-01

Worldwide amphibian population declines have been ascribed to global warming, increasing pollution levels, and other factors directly related to human activities. These factors may additionally be favoring the emergence of novel pathogens. In this report, we have determined the complete genome sequence of the emerging common midwife toad ranavirus (CMTV), which has caused fatal disease in several amphibian species across Europe. Phylogenetic and gene content analyses of the first complete genomic sequence from a ranavirus isolated in Europe show that CMTV is an amphibian-like ranavirus (ALRV). However, the CMTV genome structure is novel and represents an intermediate evolutionary stage between the two previously described ALRV groups. We find that CMTV clusters with several other ranaviruses isolated from different hosts and locations which might also be included in this novel ranavirus group. This work sheds light on the phylogenetic relationships within this complex group of emerging, disease-causing viruses.

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

PubMed

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

2006-04-01

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

Phytogeographic patterns and cryptic diversity in an aposematic toad from NW Argentina.

PubMed

Clemente-Carvalho, Rute B; Vaira, Marcos; King, Laura E; Koscinski, Daria; Bonansea, Maria I; Lougheed, Stephen C

2017-11-01

The Yungas Redbelly Toad, Melanophryniscus rubriventris, is patchily distributed in Argentina, confined to the upland portion (1000-2000m above sea level) of the montane forests of northern and central regions of Salta, and in central-eastern and south-eastern Jujuy. This species is known for its striking aposematic color variation across its geographic distribution, and was once treated as a complex of three subspecies based on distinctive color patterns. Here we assess the geographical genetic variation within M. rubriventris and quantify divergence in color and pattern among individuals sampled from Northwestern Argentina. We compare multi-gene phylogeography of M. rubriventris to patterns of dorsal and ventral coloration to test whether evolutionary affinities predict variation in warning color. Our results reveal two well-supported species lineages: one confined to the extreme northern portion of our sampling area, and the other extending over most of the Argentine portion of the species' range, within which there are two populations. However, these well-supported evolutionary relationships do not mirror the marked variation in warning coloration. This discordance between DNA genealogy and warning color variation may reflect selection brought about by differences in local predation pressures, potentially coupled with effects of sexual selection and thermoregulation. Copyright © 2017 Elsevier Inc. All rights reserved.

Black versus Black: The Relationship among African, African American, and African Caribbean Persons.

ERIC Educational Resources Information Center

Jackson, Jennifer V.; Cothran, Mary E.

2003-01-01

Surveyed people of African descent regarding relationships among African, African-American, and African-Caribbean persons, focusing on contact and friendship, travel to countries of the diaspora, cross-cultural communication, thoughts and stereotypes, and education. Most respondents had contacts with the other groups, but groups had preconceived…

Cold-adapted digestive aspartic protease of the clawed lobsters Homarus americanus and Homarus gammarus: biochemical characterization.

PubMed

Rojo, Liliana; García-Carreño, Fernando; de Los Angeles Navarrete del Toro, Maria

2013-02-01

Aspartic proteinases in the gastric fluid of clawed lobsters Homarus americanus and Homarus gammarus were isolated to homogeneity by single-step pepstatin-A affinity chromatography; such enzymes have been previously identified as cathepsin D-like enzymes based on their deduced amino acid sequence. Here, we describe their biochemical characteristics; the properties of the lobster enzymes were compared with those of its homolog, bovine cathepsin D, and found to be unique in a number of ways. The lobster enzymes demonstrated hydrolytic activity against synthetic and natural substrates at a wider range of pH; they were more temperature-sensitive, showed no changes in the K(M) value at 4°C, 10°C, and 25°C, and had 20-fold higher k(cat)/K(M) values than bovine enzyme. The bovine enzyme was temperature-dependent. We propose that both properties arose from an increase in molecular flexibility required to compensate for the reduction of reaction rates at low habitat temperatures. This is supported by the fast denaturation rates induced by temperature.

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

PubMed Central

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

2003-01-01

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

Properties of whole cell currents in isolated olfactory neurons from the chilean toad Caudiverbera caudiverbera.

PubMed

Delgado, R; Labarca, P

1993-06-01

Isolated olfactory neurons from the chilean toad Caudiverbera caudiverbera were found to possess a same set of currents. Outward currents, made of a delayed rectifier and a Ca(2+)-dependent component, were blocked by replacing K+ by Cs+ in the patch pipette, in the presence of millimolar concentrations of tetraethylammonium and 4-aminopyridine in the external solution. Inward currents were made of a transient and a maintained component. The transient was abolished in the absence of external Na+ and was blocked by tetrodotoxin, with an apparent dissociation constant (KDapp) of 25.4 +/- 0.3 nM. The maintained inward currents were suppressed on removing external Ca2+, could be carried also by Ba2+, and were selectively blocked by Cd2+ (KDapp = 3.2 +/- 1.3 microM). A variety of agents found to block the maintained Ca2+ inward currents, including Co2+ and Ni2+, at millimolar concentrations, and nifedipine, verapamil, amiloride, and the amiloride analogue benzamil, at micromolar concentrations, were also effective in either modifying the gating of, or in blocking, the transient inward currents.

Introduction pathway and climate trump ecology and life history as predictors of establishment success in alien frogs and toads

PubMed Central

Rago, Alfredo; While, Geoffrey M; Uller, Tobias

2012-01-01

A major goal for ecology and evolution is to understand how abiotic and biotic factors shape patterns of biological diversity. Here, we show that variation in establishment success of nonnative frogs and toads is primarily explained by variation in introduction pathways and climatic similarity between the native range and introduction locality, with minor contributions from phylogeny, species ecology, and life history. This finding contrasts with recent evidence that particular species characteristics promote evolutionary range expansion and reduce the probability of extinction in native populations of amphibians, emphasizing how different mechanisms may shape species distributions on different temporal and spatial scales. We suggest that contemporary changes in the distribution of amphibians will be primarily determined by human-mediated extinctions and movement of species within climatic envelopes, and less by species-typical traits. PMID:22957152

Negro, Black, Black African, African Caribbean, African American or what? Labelling African origin populations in the health arena in the 21st century

PubMed Central

Agyemang, C.; Bhopal, R.; Bruijnzeels, M.

2005-01-01

Broad terms such as Black, African, or Black African are entrenched in scientific writings although there is considerable diversity within African descent populations and such terms may be both offensive and inaccurate. This paper outlines the heterogeneity within African populations, and discusses the strengths and limitations of the term Black and related labels from epidemiological and public health perspectives in Europe and the USA. This paper calls for debate on appropriate terminologies for African descent populations and concludes with the proposals that (1) describing the population under consideration is of paramount importance (2) the word African origin or simply African is an appropriate and necessary prefix for an ethnic label, for example, African Caribbean or African Kenyan or African Surinamese (3) documents should define the ethnic labels (4) the label Black should be phased out except when used in political contexts. PMID:16286485

Potential pharmacokinetic interactions between antiretrovirals and medicinal plants used as complementary and African traditional medicines.

PubMed

Müller, Adrienne C; Kanfer, Isadore

2011-11-01

The use of traditional/complementary/alternate medicines (TCAMs) in HIV/AIDS patients who reside in Southern Africa is quite common. Those who use TCAMs in addition to antiretroviral (ARV) treatment may be at risk of experiencing clinically significant pharmacokinetic (PK) interactions, particularly between the TCAMs and the protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). Mechanisms of PK interactions include alterations to the normal functioning of drug efflux transporters, such as P-gp and/or CYP isoenzymes, such a CYP3A4 that mediate the absorption and elimination of drugs in the small intestine and liver. Specific mechanisms include inhibition and activation of these proteins and induction via the pregnane X receptor (PXR). Several clinical studies and case reports involving ARV-herb PK interactions have been reported. St John's Wort, Garlic and Cat's Claw exhibited potentially significant interactions, each with a PI or NNRTI. The potential for these herbs to induce PK interactions with drugs was first identified in reports of in vitro studies. Other in vitro studies have shown that several African traditional medicinal (ATM) plants and extracts may also demonstrate PK interactions with ARVs, through effects on CYP3A4, P-gp and PXR. The most complex effects were exhibited by Hypoxis hemerocallidea, Sutherlandia frutescens, Cyphostemma hildebrandtii, Acacia nilotica, Agauria salicifolia and Elaeodendron buchananii. Despite a high incidence of HIV/AIDs in the African region, only one clinical study, between efavirenz and Hypoxis hemerocallidea has been conducted. However, several issues/concerns still remain to be addressed and thus more studies on ATMs are warranted in order for more meaningful data to be generated and the true potential for such interactions to be determined. Copyright © 2011 John Wiley & Sons, Ltd.

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

PubMed

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

2014-09-01

The toxicity of Nonylphenol, an emerging pollutant, on the common South American toad Rhinella arenarum was stage and time dependent, thus Median Lethal Concentrations (LC50) for acute (96h), short-term chronic (168h) and chronic exposure (336h) were 1.06; 0.96 and 0.17mgNP/L from embryonic period (S.4), whereas for exposure from larvae (S.25), LC50 remained constant at 0.37mgNP/L from 96h to 168h, decreasing to 0.11mgNP/L at 336h. NOEC-168h for exposure from embryos was 0.025mgNP/L. The Teratogenic Potential (NOEC-lethality/NOEC-sublethal effects) was 23 times higher than the threshold value, indicating a high risk for embryos to be malformed in absence of significant lethality and representing a threat for the species conservation. By comparing with other amphibians, the early development of R. arenarum was very sensitive to NP. The results highlight the relevance of extending the exposure time and look for the most sensitive stage in order to perform the bioassays for conservation purposes. Copyright © 2014 Elsevier B.V. All rights reserved.

Host-defense and trefoil factor family peptides in skin secretions of the Mawa clawed frog Xenopus boumbaensis (Pipidae).

PubMed

Conlon, J Michael; Mechkarska, Milena; Kolodziejek, Jolanta; Leprince, Jérôme; Coquet, Laurent; Jouenne, Thierry; Vaudry, Hubert; Nowotny, Norbert; King, Jay D

2015-10-01

Peptidomic analysis of norepinephrine-stimulated skin secretions from the octoploid Mawa clawed frog Xenopus boumbaensis Loumont, 1983 led to the identification and characterization of 15 host-defense peptides belonging to the magainin (two peptides), peptide glycine-leucine-amide (PGLa; three peptides), xenopsin precursor fragment (XPF; three peptides), caerulein precursor fragment (CPF; two peptides), and caerulein precursor fragment-related peptide (CPF-RP; five peptides) families. In addition, caerulein and three peptides with structural similarity to the trefoil factor family (TFF) peptides, xP2 and xP4 from Xenopus laevis were also present in the secretions. Consistent with data from comparisons of the nucleotides sequence of mitochondrial and nuclear genes, the primary structures of the peptides suggest a close phylogenetic relationship between X. boumbaensis and the octoploid frogs Xenopus amieti and Xenopus andrei. As the three species occupy disjunct ranges within Cameroon, it is suggested that they diverged from a common ancestor by allopatric speciation. Copyright © 2015 Elsevier Inc. All rights reserved.

A new species of flea-toad (Anura: Brachycephalidae) from southern Atlantic Forest, Brazil.

PubMed

Condez, Thais Helena; Monteiro, Juliane Petry De Carli; Comitti, Estevão Jasper; Garcia, Paulo Christiano De Anchietta; Amaral, Ivan Borel; Haddad, Célio Fernando Baptista

2016-02-18

We describe a new species of Brachycephalus that is morphologically similar to the flea-toads B. didactylus, B. hermogenesi, and B. pulex. The new species occurs from the sea level up to 1000 m and it is widely distributed throughout southern Atlantic Forest. Brachycephalus sulfuratus sp. nov. is distinguished from all of its congeners by the combination of the following characters: (1) small body size (SVL of adults: 7.4-8.5 mm for males and 9.0-10.8 mm for females); (2) "leptodactyliform" body; (3) pectoral girdle arciferal and less robust compared to the Brachycephalus species with "bufoniform" body; (4) procoracoid and epicoracoid fused with coracoid but separated from the clavicle by a large fenestrae; (5) toe I externally absent; toes II, III, IV, and V distinct; phalanges of toes II and V reduced; (6) skin smooth with no dermal ossifications; (7) in life, general background color brown with small dark-brown spots; skin of throat, chest, arms, and forearms with irregular yellow blotches; in ventral view, cloacal region of alive and preserved specimens surrounded by a dark-brown inverted v-shaped mark outlined with white; (8) advertisement call long, composed of a set of 4-7 high-frequency notes (6.2-7.2 kHz) repeated regularly.

Selective inhibition of osmotic water flow by general anesthetics to toad urinary bladder.

PubMed Central

Levine, S D; Levine, R D; Worthington, R E; Hays, R M

1976-01-01

Vasopressin increases the permeability of the total urinary bladder, an analogue of the mammalian renal collecting duct, to water and small solutes, especially the amide urea. We have observed that three general anesthetic agents of clinical importance, the gases methoxyflurane and halothane and the ultrashortacting barbiturate methohexital, reversibly inhibit vasopressin-stimulated water flow, but do not depress permeability to urea, or the the lipophilic solute diphenylhydantoin. In contrast to their effects in vasopressin-treated bladders, the anesthetics do not inhibit cyclic AMP-stimulated water flow, consistent with an effect on vasopressin-responsive adenylate cyclase. The selectivity of the anesthetic-induced depression of water flow suggests that separate adenylate cyclases and cyclic AMP pools may exist for control of water and urea permeabilities in to toad bladder. Furthermore, theophylline's usual stimulatory effect on water flow, but not its effect on urea permeability, was entirely abolished in methoxyflurane-treated bladders, suggesting that separate phosphodiesterases that control water and urea permeabilities are present as well. We conclude that the majority of water and urea transport takes place via separate pathways across the rate-limiting luminal membrane of the bladder cell, and that separate vasopressin-responsive cellular pools of cyclic AMP appear to control permeability to water and to urea. PMID:184113

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

PubMed

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

2011-11-01

Toe-clipping, the removal of one or more toes, is a common method used to individually mark free-living animals. Whilst this method is widely used in studies of amphibians, the appropriateness of the method, and its potential detrimental effects have been the subject of debate. Here, we provide for the first time, evidence that toe-clipping is a stressor in a wild amphibian. We measured urinary corticosterone responses of male cane toads (Rhinella marina) to capture and handling only, and to toe-clipping under field conditions. Urinary testosterone concentrations and white blood cell proportions were also measured. Urinary corticosterone metabolite concentrations increased 6h after capture and handling only and remained high for 24h; corticosterone returned to baseline levels after 48 h and remained low at 72 h post capture and handling. Corticosterone concentrations in toads subjected to toe-clipping increased at 6h to significantly higher concentrations than after capture and handling only, then decreased more slowly than after capture and handling, and were still elevated (approximately double basal level) 72 h after toe-clipping. Testosterone did not change significantly after capture and handling only, whereas after toe-clipping testosterone decreased at 6h and remained low at 72 h. There were weak short-term effects of toe-clipping compared with capture and handling only on white blood cell proportions. We have clearly shown that toe-clipping is a distinctly stronger stressor than capture and handling alone. This indicates that there is an ethical cost of toe-clipping, and this should be considered when planning studies of amphibians. Copyright © 2011 Elsevier Inc. All rights reserved.

Ultrastructural Comparison of Hepatozoon ixoxo and Hepatozoon theileri (Adeleorina: Hepatozoidae), Parasitising South African Anurans.

PubMed

Conradie, Roxanne; Cook, Courtney A; du Preez, Louis H; Jordaan, Anine; Netherlands, Edward C

2017-03-01

To date, only two haemogregarine parasite species have been described from South African anurans: Hepatozoon ixoxo, infecting toads of the genus Sclerophrys (syn. Amietophrynus); and Hepatozoon theileri, parasitising the common river frog, Amietia quecketti. Both species have been characterised using limited morphology, and molecular data from PCR amplified fragments of the 18S rRNA gene. However, no ultrastructural work has been performed thus far. The aim of this study was to add descriptive information on the two species by studying their ultrastructural morphology. Mature gamont stages, common in the peripheral blood of infected frogs, were examined by transmission electron microscopy. Results indicate that H. ixoxo and H. theileri share typical apicomplexan characteristics, but differ markedly in their external cellular structure. Hepatozoon ixoxo is an encapsulated parasite presenting a prominent cap at the truncate pole, and shows no visible modifications to the host cell membrane. In comparison, H. theileri does not present a capsule or cap, and produces marked morphological changes to its host cell. Scanning electron microscopy was performed to further examine the cytopathological effects of H. theileri, and results revealed small, knob-like protrusions on the erythrocyte surface, as well as notable distortion of the overall shape of the host cell. © 2016 The Author(s) Journal of Eukaryotic Microbiology © 2016 International Society of Protistologists.

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

PubMed

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

2013-06-01

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

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

PubMed

Gipouloux, J D; Hakim, J

1975-10-13

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

Blood lead levels, δ-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.

PubMed

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

2013-02-01

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 μg/dL and are significantly higher in industrial sites. We have found a significant decrease in the delta-aminolevulinic acid dehydratase (δ-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 δ-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 δ-ALAD activity inhibition and hematological alterations at low lead concentrations.

The anuran Bauplan: a review of the adaptive, developmental, and genetic underpinnings of frog and tadpole morphology.

PubMed

Handrigan, Gregory R; Wassersug, Richard J

2007-02-01

Anurans (frogs, toads, and their larvae) are among the most morphologically derived of vertebrates. While tightly conserved across the order, the anuran Bauplan (body plan) diverges widely from that of other vertebrates, particularly with respect to the skeleton. Here we address the adaptive, ontogenetic, and genetic bases of three such hallmark anuran features: (1) the absence of discrete caudal vertebrae, (2) a truncated axial skeleton, and (3) elongate hind limbs. We review the functional significance of each as it relates to the anuran lifestyle, which includes locomotor adaptations to both aquatic and terrestrial environments. We then shift our focus to the proximal origins of each feature, namely, ontogeny and its molecular regulation. Drawing on relatively limited data, we detail the development of each character and then, by extrapolating from comparative vertebrate data, propose molecular bases for these processes. Cast in this light, the divergent morphology of anurans emerges as a product of evolutionary modulation of the generalised vertebrate developmental machinery. Specifically, we hypothesise that: (1) the formation of caudal vertebrae is precluded due to a failure of sclerotomes to form cartilaginous condensations, perhaps resulting from altered expression of a suite of genes, including Pax1, Pax9, Msx1, Uncx-4.1, Sonic hedgehog, and noggin; (2) anteriorised Hox gene expression in the paraxial mesoderm has led to a rostral shift of morphological boundaries of the vertebral column; and, (3) spatial and temporal shifts in Hox expression may underlie the expanded tarsal elements of the anuran hind limb. Technology is currently in place to investigate each of these scenarios in the African clawed frog Xenopus. Experimental corroboration will further our understanding of the molecular regulation of the anuran Bauplan and provide insight into the origin of vertebrate morphological diversity as well as the role of development in evolution.

Lethal and sublethal measures of chronic copper toxicity in the eastern narrowmouth toad, Gastrophryne carolinensis.

PubMed

Flynn, R Wesley; Scott, David E; Kuhne, Wendy; Soteropoulos, Diana; Lance, Stacey L

2015-03-01

Many metals are acutely toxic to aquatic organisms at high concentrations and for some metals, such as copper (Cu), even low-level chronic contamination may be cause for conservation concern. Amphibian susceptibility to Cu has been examined in only a few species, and susceptibility is highly variable. The lethal and sublethal effects were examined of chronic aqueous Cu exposure on embryonic and larval eastern narrowmouth toads, Gastrophryne carolinensis. Copper levels as low as 10 μg Cu/L reduced embryonic and larval survival. Embryonic survivorship varied within- and between-source populations, with embryos derived from uncontaminated-wetland parents having greater survival at lower Cu levels than embryos from parents from a metal-contaminated constructed wetland. At 30 μg/L, embryos from the contaminated site had greater survival. Overall survival from oviposition to metamorphosis was 68.9% at 0 μg/L and 5.4% at 10 μg/L. Similarly, embryos exposed to ≥50 μg/L demonstrated developmental delays in transition from embryo to free-swimming larva. These results demonstrate a negative population-specific response to environmentally relevant levels of Cu. © 2014 SETAC.

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

PubMed Central

Burgos, Mario H.; Fawcett, Don W.

1956-01-01

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

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

PubMed

Liu, Lu; Murray, Michael; Burcher, Elizabeth

2002-01-15

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

African Ancestry Is Associated with Asthma Risk in African Americans

PubMed Central

Pino-Yanes, María; Wade, Michael S.; Pérez-Méndez, Lina; Kittles, Rick A.; Wang, Deli; Papaiahgari, Srinivas; Ford, Jean G.; Kumar, Rajesh; Garcia, Joe G. N.

2012-01-01

Background Asthma is a common complex condition with clear racial and ethnic differences in both prevalence and severity. Asthma consultation rates, mortality, and severe symptoms are greatly increased in African descent populations of developed countries. African ancestry has been associated with asthma, total serum IgE and lower pulmonary function in African-admixed populations. To replicate previous findings, here we aimed to examine whether African ancestry was associated with asthma susceptibility in African Americans. In addition, we examined for the first time whether African ancestry was associated with asthma exacerbations. Methodology/Principal Findings After filtering for self-reported ancestry and genotype data quality, samples from 1,117 self-reported African-American individuals from New York and Baltimore (394 cases, 481 controls), and Chicago (321 cases followed for asthma exacerbations) were analyzed. Genetic ancestry was estimated based on ancestry informative markers (AIMs) selected for being highly divergent among European and West African populations (95 AIMs for New York and Baltimore, and 66 independent AIMs for Chicago). Among case-control samples, the mean African ancestry was significantly higher in asthmatics than in non-asthmatics (82.0±14.0% vs. 77.8±18.1%, mean difference 4.2% [95% confidence interval (CI):2.0–6.4], p<0.0001). This association remained significant after adjusting for potential confounders (odds ratio: 4.55, 95% CI: 1.69–12.29, p = 0.003). African ancestry failed to show an association with asthma exacerbations (p = 0.965) using a model based on longitudinal data of the number of exacerbations followed over 1.5 years. Conclusions/Significance These data replicate previous findings indicating that African ancestry constitutes a risk factor for asthma and suggest that elevated asthma rates in African Americans can be partially attributed to African genetic ancestry. PMID:22235241

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

PubMed

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

2013-04-01

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

Molecular effectors in the chronic exposure to arsenic as early and sensitive biomarkers in developing Rhinella arenarum toads.

PubMed

Mardirosian, Mariana Noelia; Ceschin, Danilo Guillermo; Lascano, Cecilia Inés; Venturino, Andrés

2017-05-01

Arsenic, a natural element of ecological relevance, is one of the most toxic elements present in various regions of the world. It can be found in natural water sources throughout Argentina in concentrations between 0.01 and 15mgL -1 . The Argentinean autochthonous toad Rhinella arenarum was selected to study the molecular mechanisms involved in the effects and response to the chronic As exposure along its embryonic and larval development. We evaluated the effects on MAPK signal transduction pathway and transcription factors c-FOS and c-JUN, and the regulation of the expression at protein levels of different antioxidant enzymes. Our results indicated that As is modulating the MAPK pathway, increasing MEK and ERK levels both in the nuclear and post-nuclear fraction along the embryonic development and mainly at the beginning of the larval stage. Through this pathway, As can upregulate transcription factors like c-FOS and c-JUN, impacting the antioxidant response of the exposed embryos and larvae through antioxidant enzymes and recycling of GSH. Arsenic triggered specifically the synthesis of antioxidant enzymes in exposed R. arenarum embryo and larvae. In particular, the expression levels of SOD, CAT and GST enzymes analyzed by Western blot showed a similar behavior to their enzymatic activities in our previous work. This fact suggests that not only the synthesis of these antioxidant enzymes but also their rapid degradation after inactivation would be regulated in response to ROS levels. Antioxidant enzymes may show dual responses of induction and inactivation followed by degradation depending on the levels of oxidative stress and impact on ROS targets when the exposure is sustained in time and intensity. We also performed a probability of exceedence analysis including our previous results to visualize a progression of the response in time and also established the best early-responding biomarkers at the lowest As concentrations. As a conclusion, the molecular

Identification of proteins interacting with lactate dehydrogenase in claw muscle of the porcelain crab Petrolisthes cinctipes

PubMed Central

Cayenne, Andrea P.; Gabert, Beverly; Stillman, Jonathon H.

2011-01-01

Biochemical adaptation of enzymes involves conservation of activity, stability and affinity across a wide range of intracellular and environmental conditions. Enzyme adaptation by alteration of primary structure is well known, but the roles of protein-protein interactions in enzyme adaptation are less well understood. Interspecific differences in thermal stability of lactate dehydrogenase (LDH) in porcelain crabs (genus Petrolisthes) are related to intrinsic differences among LDH molecules and by interactions with other stabilizing proteins. Here, we identified proteins that interact with LDH in porcelain crab claw muscle tissue using co-immunoprecipitation, and showed LDH exists in high molecular weight complexes using size exclusion chromatography and Western blot analyses. Co-immunoprecipitated proteins were separated using 2D SDS PAGE and analyzed by LC/ESI using peptide MS/MS. Peptide MS/MS ions were compared to an EST database for Petrolisthes cinctipes to identify proteins. Identified proteins included cytoskeletal elements, glycolytic enzymes, a phosphagen kinase, and the respiratory protein hemocyanin. Our results support the hypothesis that LDH interacts with glycolytic enzymes in a metabolon structured by cytoskeletal elements that may also include the enzyme for transfer of the adenylate charge in glycolytically produced ATP. Those interactions may play specific roles in biochemical adaptation of glycolytic enzymes. PMID:21968246

A suite of molecular markers for identifying species, detecting introgression and describing population structure in spadefoot toads (Spea spp.).

PubMed

Pfennig, Karin S; Allenby, Ashley; Martin, Ryan A; Monroy, Anaïs; Jones, Corbin D

2012-09-01

Two congeneric species of spadefoot toad, Spea multiplicata and Spea bombifrons, have been the focus of hybridization studies since the 1970s. Because complex hybrids are not readily distinguished phenotypically, genetic markers are needed to identify introgressed individuals. We therefore developed a set of molecular markers (amplified fragment length polymorphism, polymerase chain reaction-restriction fragment length polymorphism and single nucleotide polymorphism) for identifying pure-species, F1 hybrids and more complex introgressed types. To do so, we tested a series of markers across both species and known hybrids using populations in both allopatry and sympatry. We retained those markers that differentiated the two pure-species and also consistently identified known species hybrids. These markers are well suited for identifying hybrids between these species. Moreover, those markers that show variation within each species can be used in conjunction with existing molecular markers in studies of population structure and gene flow. © 2012 Blackwell Publishing Ltd.

The Genetic Structure and History of Africans and African Americans

PubMed Central

Tishkoff, Sarah A.; Reed, Floyd A.; Friedlaender, Françoise R.; Ehret, Christopher; Ranciaro, Alessia; Froment, Alain; Hirbo, Jibril B.; Awomoyi, Agnes A.; Bodo, Jean-Marie; Doumbo, Ogobara; Ibrahim, Muntaser; Juma, Abdalla T.; Kotze, Maritha J.; Lema, Godfrey; Moore, Jason H.; Mortensen, Holly; Nyambo, Thomas B.; Omar, Sabah A.; Powell, Kweli; Pretorius, Gideon S.; Smith, Michael W.; Thera, Mahamadou A.; Wambebe, Charles; Weber, James L.; Williams, Scott M.

2010-01-01

Africa is the source of all modern humans, but characterization of genetic variation and of relationships among populations across the continent has been enigmatic. We studied 121 African populations, four African American populations, and 60 non-African populations for patterns of variation at 1327 nuclear microsatellite and insertion/deletion markers. We identified 14 ancestral population clusters in Africa that correlate with self-described ethnicity and shared cultural and/or linguistic properties. We observed high levels of mixed ancestry in most populations, reflecting historical migration events across the continent. Our data also provide evidence for shared ancestry among geographically diverse hunter-gatherer populations (Khoesan speakers and Pygmies). The ancestry of African Americans is predominantly from Niger-Kordofanian (~71%), European (~13%), and other African (~8%) populations, although admixture levels varied considerably among individuals. This study helps tease apart the complex evolutionary history of Africans and African Americans, aiding both anthropological and genetic epidemiologic studies. PMID:19407144

African American Males. A Critical Link in the African American Family.

ERIC Educational Resources Information Center

Jones, Dionne J., Ed.

African Americans are experiencing extreme stress in the United States, and African-American males appear to suffer the most. The chapters in this volume examine some of the issues confronting African-American men today. They include: (1) "Introduction" (Dionne J. Jones); (2) "Reaffirming Young African American Males: Mentoring and…

The TG/HDL-C ratio does not predict insulin resistance in overweight women of African descent: a study of South African, African American and West African women.

PubMed

Knight, Michael G; Goedecke, Julia H; Ricks, Madia; Evans, Juliet; Levitt, Naomi S; Tulloch-Reid, Marshall K; Sumner, Anne E

2011-01-01

Women of African descent have a high prevalence of diseases caused by insulin resistance. To positively impact cardiometabolic health in Black women, effective screening tests for insulin resistance must be identified. Recently, the TG/HDL-C ratio has been recommended as a tool to predict insulin resistance in overweight people. While the ratio predicts insulin resistance in White women, it is ineffective in African American women. As there are no data for African women, we tested the ability of the TG/HDL-C ratio to predict insulin resistance in Black women from South Africa, West Africa and the United States. For comparison, the ratio was also tested in White women from South Africa. Participants were 801 women (157 Black South African, 382 African American, 119 West African, 143 White South African, age 36 +/- 9y [mean +/- SD]). Standardized scores were created from log-transformed homeostasis model assessment-insulin resistance values from each population. Participants in the upper third of their population distribution were classified as insulin-resistant. To predict insulin resistance by the TC/HDL-C ratio, area under the receiver operating characteristic (AUC-ROC) curve was used and criteria were: 0.50 for no discrimination and > or = 0.70 for acceptable. Seventy-one percent of the Black women were overweight vs 51% of White women (P<.01). In overweight White women, AUC-ROC curve for prediction of insulin resistance by TG/HDL-C was 0.76 +/- 0.06, but below the 0.70 threshold in each group of overweight Black women (Black South African: 0.64 +/- 0.06, African American: 0.66 +/- 0.03, and West African: 0.63 +/- 0.07). Therefore, TG/HDL-C does not predict insulin resistance in overweight African American women and this investigation extends that finding to overweight Black South African and West African women. Resources to identify effective markers of insulin resistance are needed to improve cardiometabolic health in women of African descent.

Africans in America.

ERIC Educational Resources Information Center

Hart, Ayanna; Spangler, Earl

This book introduces African-American history and culture to children. The first Africans in America came from many different regions and cultures, but became united in this country by being black, African, and slaves. Once in America, Africans began a long struggle for freedom which still continues. Slavery, the Civil War, emancipation, and the…

Iris-claw versus posterior chamber fixation intraocular lens implantation in pediatric traumatic cataract☆

PubMed Central

Kavitha, V; Balasubramanian, Preethi; Heralgi, Mallikarjun M.

2016-01-01

Aim: This study aims to compare visual outcomes and complications of iris-fixated (claw) intraocular lens (IFIOL) implantation with those of posterior chamber intraocular lens (PCIOL) implantation in children with traumatic cataract. Settings and design: Retrospective observational clinical audit. Materials and methods: A total of 50 pediatric traumatic cataract cases that underwent lens removal and IOL implantation (IFIOL or PCIOL) with or without corneal or corneoscleral tear repair between January 2009 and December 2013 were analyzed. After meeting the eligibility criteria, their pre- and postoperative visual outcomes and complication rates were recorded. Data were analyzed descriptively. Results: Out of 50 children, IFIOL and PCIOL implantations were performed in one eye of each of 25 children. Their mean age was 11 ± 4 years (range 4–18 years). Primary (cataract removal with lens implantation) and secondary (corneal tear repair followed by cataract removal with lens implantation) procedures were performed in 19 (76%) and six (24%) children in the IFIOL group and in 21 (84%) and four (16%) children in the PCIOL group, respectively. There was an improvement in best corrected visual acuity postimplantation in both the IFIOL and the PCIOL group, and no significant difference in the logarithm of the minimum angle of resolution of best corrected visual acuity was observed between the two groups over 36 months. Only three eyes in the IFIOL group developed complications: one eye developed secondary glaucoma, one disenclavation of IOL haptic, and one cystoid macular edema. Conclusion: Both IFIOL and PCIOL implantations have good visual outcomes and minimal postoperative complications; therefore, IFIOL can be used as an alternative to PCIOL in children with traumatic cataract with inadequate capsular support. PMID:29018714

Iris-Claw Intraocular Lens and Scleral-Fixated Posterior Chamber Intraocular Lens Implantations in Correcting Aphakia: A Meta-Analysis.

PubMed

Jing, Wu; Guanlu, Liang; Qianyin, Zheng; Shuyi, Li; Fengying, He; Jian, Liu; Wen, Xu

2017-07-01

A meta-analysis to compare iris-claw intraocular lens (IC-IOL) and scleral-fixated posterior chamber intraocular lens (SF-PCIOL) implantations in correcting aphakia without sufficient capsular support. Eligible studies were collected through PubMed, Web of Science, Embase, and the Cochrane library. The pooled relative risks (RR), pooled standardized mean difference (SMD), and their 95% confidence interval of the eligible studies were then calculated. Seven studies met our inclusion criteria, involving 232 and 158 eyes in IC-IOL and SF-PCIOL groups, respectively. The pooled SMD of the mean postoperative corrected distance visual acuity (CDVA) (logMAR) was -0.25. The pooled RR of the eyes achieving 20/40 or better postoperatively was 1.16. The pooled SMD of the surgical time was -2.97. The pooled RR of the surgical complications was 0.86. The pooled RR of IOL dislocation, retinal detachment (RD), and cystoid macular edema (CME) between the two groups were 0.22, 0.63, and 0.64. Implantation of IC-IOL has a more simple procedure and shorter learning curve than SF-PCIOL implantation in correcting aphakia without sufficient capsular support.

African American and Black Caribbean Feelings of Closeness to Africans

PubMed Central

Thornton, Michael C.; Taylor, Robert Joseph; Chatters, Linda M.; Forsythe-Brown, Ivy

2016-01-01

African American and Black Caribbean relations dominate research on interactions across black ethnic divides. Using National Survey of American Life data, we explore a different aspect of black interethnic attitudes: how close these groups feel toward Africans. African Americans and Black Caribbeans were largely similar in their feelings of closeness to Africans. For Black Caribbeans, younger and male respondents, those reporting higher levels of financial strain, living in the northeast and persons who immigrated to the United States at least 11 years ago, report feeling especially close to Africans. Being male was the only significant correlate among African Americans. The findings are discussed in relation to how race, ethnicity and national origin shape personal identities within the U.S. and their significance for intergroup perceptions. These broader issues warrant further consideration in light of assertions that race as a defining feature of American life and intergroup relations is obsolete. PMID:28943747

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

PubMed

Canosa, L F; Ceballos, N R

2002-05-01

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

Identifying tagging SNPs for African specific genetic variation from the African Diaspora Genome

PubMed Central

Johnston, Henry Richard; Hu, Yi-Juan; Gao, Jingjing; O’Connor, Timothy D.; Abecasis, Gonçalo R.; Wojcik, Genevieve L; Gignoux, Christopher R.; Gourraud, Pierre-Antoine; Lizee, Antoine; Hansen, Mark; Genuario, Rob; Bullis, Dave; Lawley, Cindy; Kenny, Eimear E.; Bustamante, Carlos; Beaty, Terri H.; Mathias, Rasika A.; Barnes, Kathleen C.; Qin, Zhaohui S.; Preethi Boorgula, Meher; Campbell, Monica; Chavan, Sameer; Ford, Jean G.; Foster, Cassandra; Gao, Li; Hansel, Nadia N.; Horowitz, Edward; Huang, Lili; Ortiz, Romina; Potee, Joseph; Rafaels, Nicholas; Ruczinski, Ingo; Scott, Alan F.; Taub, Margaret A.; Vergara, Candelaria; Levin, Albert M.; Padhukasahasram, Badri; Williams, L. Keoki; Dunston, Georgia M.; Faruque, Mezbah U.; Gietzen, Kimberly; Deshpande, Aniket; Grus, Wendy E.; Locke, Devin P.; Foreman, Marilyn G.; Avila, Pedro C.; Grammer, Leslie; Kim, Kwang-Youn A.; Kumar, Rajesh; Schleimer, Robert; De La Vega, Francisco M.; Shringarpure, Suyash S.; Musharoff, Shaila; Burchard, Esteban G.; Eng, Celeste; Hernandez, Ryan D.; Pino-Yanes, Maria; Torgerson, Dara G.; Szpiech, Zachary A.; Torres, Raul; Nicolae, Dan L.; Ober, Carole; Olopade, Christopher O; Olopade, Olufunmilayo; Oluwole, Oluwafemi; Arinola, Ganiyu; Song, Wei; Correa, Adolfo; Musani, Solomon; Wilson, James G.; Lange, Leslie A.; Akey, Joshua; Bamshad, Michael; Chong, Jessica; Fu, Wenqing; Nickerson, Deborah; Reiner, Alexander; Hartert, Tina; Ware, Lorraine B.; Bleecker, Eugene; Meyers, Deborah; Ortega, Victor E.; Maul, Pissamai; Maul, Trevor; Watson, Harold; Ilma Araujo, Maria; Riccio Oliveira, Ricardo; Caraballo, Luis; Marrugo, Javier; Martinez, Beatriz; Meza, Catherine; Ayestas, Gerardo; Francisco Herrera-Paz, Edwin; Landaverde-Torres, Pamela; Erazo, Said Omar Leiva; Martinez, Rosella; Mayorga, Alvaro; Mayorga, Luis F.; Mejia-Mejia, Delmy-Aracely; Ramos, Hector; Saenz, Allan; Varela, Gloria; Marina Vasquez, Olga; Ferguson, Trevor; Knight-Madden, Jennifer; Samms-Vaughan, Maureen; Wilks, Rainford J.; Adegnika, Akim; Ateba-Ngoa, Ulysse; Yazdanbakhsh, Maria

2017-01-01

A primary goal of The Consortium on Asthma among African-ancestry Populations in the Americas (CAAPA) is to develop an ‘African Diaspora Power Chip’ (ADPC), a genotyping array consisting of tagging SNPs, useful in comprehensively identifying African specific genetic variation. This array is designed based on the novel variation identified in 642 CAAPA samples of African ancestry with high coverage whole genome sequence data (~30× depth). This novel variation extends the pattern of variation catalogued in the 1000 Genomes and Exome Sequencing Projects to a spectrum of populations representing the wide range of West African genomic diversity. These individuals from CAAPA also comprise a large swath of the African Diaspora population and incorporate historical genetic diversity covering nearly the entire Atlantic coast of the Americas. Here we show the results of designing and producing such a microchip array. This novel array covers African specific variation far better than other commercially available arrays, and will enable better GWAS analyses for researchers with individuals of African descent in their study populations. A recent study cataloging variation in continental African populations suggests this type of African-specific genotyping array is both necessary and valuable for facilitating large-scale GWAS in populations of African ancestry. PMID:28429804

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

PubMed

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

2006-10-01

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

Effect of hydroxylamine on photon-like events during dark adaptation in toad rod photoreceptors.

PubMed Central

Leibrock, C S; Lamb, T D

1997-01-01

1. The suction pipette technique was used to investigate the recovery of toad rod photoreceptors following small bleaches of 0.2-3% of the rhodopsin. 2. The reduction in sensitivity and the increase in noise elicited by bleaches were measured, and from these measurements the underlying rate of occurrence of photon-like events was calculated as a function of time after the bleach. 3. Exposure to hydroxylamine solution was used to hasten the decomposition of the metarhodopsin photoproducts. The outer segment was exposed to 110 mM hydroxylamine in a low-Ca2+ Ringer solution for a period of 10-50 s beginning 10-17 min after the bleaching exposure. 4. By the time of the hydroxylamine exposure, the flash sensitivity and response kinetics had returned almost to normal, and were not significantly altered by the exposure. 5. Following hydroxylamine exposure, the rate of spontaneous photon-like events in the rods declined rapidly to near pre-bleach levels. 6. We conclude that hydroxylamine reduces the rate of occurrence of photon-like events induced by a bleach, and we postulate that this reduction results from the removal of metarhodopsin (most likely metarhodopsin II) from the outer segment. 7. Our results are consistent with a model in which photon-like events result from reversal of the reactions (phosphorylation and capping by arrestin) that lead to inactivation of the activated form of rhodopsin, Rh*. PMID:9174997

Thermal performance curves under daily thermal fluctuation: A study in helmeted water toad tadpoles.

PubMed

Bartheld, José L; Artacho, Paulina; Bacigalupe, Leonardo

2017-12-01

Most research in physiological ecology has focused on the effects of mean changes in temperature under the classic "hot vs cold" acclimation treatment; however, current evidence suggests that an increment in both the mean and variance of temperature could act synergistically to amplify the negative effects of global temperature increase and how it would affect fitness and performance-related traits in ectothermic organisms. We assessed the effects of acclimation to daily variance of temperature on thermal performance curves of swimming speed in helmeted water toad tadpoles (Calyptocephalella gayi). Acclimation treatments were 20°C ± 0.1 SD (constant) and 20°C ± 1.5 SD (fluctuating). We draw two key findings: first, tadpoles exposed to daily temperature fluctuation had reduced maximal performance (Z max ), and flattened thermal performance curves, thus supporting the "vertical shift or faster-slower" hypothesis, and suggesting that overall swimming performance would be lower through an examination of temperatures under more realistic and ecologically-relevant fluctuating regimens; second, there was significant interindividual variation in performance traits by means of significant repeatability estimates. Our present results suggest that the widespread use of constant acclimation temperatures in laboratory experiments to estimate thermal performance curves (TPCs) may lead to an overestimation of actual organismal performance. We encourage the use of temperature fluctuation acclimation treatments to better understand the variability of physiological traits, which predict ecological and evolutionary responses to global change. Copyright © 2017 Elsevier Ltd. All rights reserved.

Antileishmanial and antitrypanosomal activity of bufadienolides isolated from the toad Rhinella jimi parotoid macrogland secretion.

PubMed

Tempone, André Gustavo; Pimenta, Daniel Carvalho; Lebrun, Ivo; Sartorelli, Patrícia; Taniwaki, Noemi N; de Andrade, Heitor Franco; Antoniazzi, Marta Maria; Jared, Carlos

2008-07-01

Amphibian skin secretions are considered a rich source of biologically active compounds and are known to be rich in peptides, bufadienolides and alkaloids. Bufadienolides are cardioactive steroids from animals and plants that have also been reported to possess antimicrobial activities. Leishmaniasis and American Trypanosomiasis are parasitic diseases found in tropical and subtropical regions. The efforts toward the discovery of new treatments for these diseases have been largely neglected, despite the fact that the only available treatments are highly toxic drugs. In this work, we have isolated, through bioguided assays, the major antileishmanial compounds of the toad Rhinella jimi parotoid macrogland secretion. Mass spectrometry and (1)H and (13)C NMR spectroscopic analyses were able to demonstrate that the active molecules are telocinobufagin and hellebrigenin. Both steroids demonstrated activity against Leishmania (L.) chagasi promastigotes, but only hellebrigenin was active against Trypanosoma cruzi trypomastigotes. These steroids were active against the intracellular amastigotes of Leishmania, with no activation of nitric oxide production by macrophages. Neither cytotoxicity against mouse macrophages nor hemolytic activities were observed. The ultrastructural studies with promastigotes revealed the induction of mitochondrial damage and plasma membrane disturbances by telocinobufagin, resulting in cellular death. This novel biological effect of R. jimi steroids could be used as a template for the design of new therapeutics against Leishmaniasis and American Trypanosomiasis.

Conversation on African Music.

ERIC Educational Resources Information Center

Saunders, Leslie R.

1985-01-01

A voice and music education teacher at the University of Lagos, Nigeria, talks about African music in this interview. Topics discussed include differences between African and Western music, African melody, rules for composing African music, the theory of counterpoint, and the popularity of classical composers in Nigeria. (RM)

The African Connection

ERIC Educational Resources Information Center

Oguntoyinbo, Lekan

2012-01-01

From student and faculty exchanges to joint research projects, U.S. universities maintain a broad spectrum of collaborative relationships with African universities. It's unclear how many U.S. colleges and universities have partnerships with African universities. The African Studies Association, an organization of scholars, doesn't keep that kind…

Monitoring of noble, signal and narrow-clawed crayfish using environmental DNA from freshwater samples.

PubMed

Agersnap, Sune; Larsen, William Brenner; Knudsen, Steen Wilhelm; Strand, David; Thomsen, Philip Francis; Hesselsøe, Martin; Mortensen, Peter Bondgaard; Vrålstad, Trude; Møller, Peter Rask

2017-01-01

For several hundred years freshwater crayfish (Crustacea-Decapoda-Astacidea) have played an important ecological, cultural and culinary role in Scandinavia. However, many native populations of noble crayfish Astacus astacus have faced major declines during the last century, largely resulting from human assisted expansion of non-indigenous signal crayfish Pacifastacus leniusculus that carry and transmit the crayfish plague pathogen. In Denmark, also the non-indigenous narrow-clawed crayfish Astacus leptodactylus has expanded due to anthropogenic activities. Knowledge about crayfish distribution and early detection of non-indigenous and invasive species are crucial elements in successful conservation of indigenous crayfish. The use of environmental DNA (eDNA) extracted from water samples is a promising new tool for early and non-invasive detection of species in aquatic environments. In the present study, we have developed and tested quantitative PCR (qPCR) assays for species-specific detection and quantification of the three above mentioned crayfish species on the basis of mitochondrial cytochrome oxidase 1 (mtDNA-CO1), including separate assays for two clades of A. leptodactylus. The limit of detection (LOD) was experimentally established as 5 copies/PCR with two different approaches, and the limit of quantification (LOQ) were determined to 5 and 10 copies/PCR, respectively, depending on chosen approach. The assays detected crayfish in natural freshwater ecosystems with known populations of all three species, and show promising potentials for future monitoring of A. astacus, P. leniusculus and A. leptodactylus. However, the assays need further validation with data 1) comparing traditional and eDNA based estimates of abundance, and 2) representing a broader geographical range for the involved crayfish species.

Monitoring of noble, signal and narrow-clawed crayfish using environmental DNA from freshwater samples

PubMed Central

Knudsen, Steen Wilhelm; Strand, David; Thomsen, Philip Francis; Hesselsøe, Martin; Mortensen, Peter Bondgaard; Vrålstad, Trude; Møller, Peter Rask

2017-01-01

For several hundred years freshwater crayfish (Crustacea—Decapoda—Astacidea) have played an important ecological, cultural and culinary role in Scandinavia. However, many native populations of noble crayfish Astacus astacus have faced major declines during the last century, largely resulting from human assisted expansion of non-indigenous signal crayfish Pacifastacus leniusculus that carry and transmit the crayfish plague pathogen. In Denmark, also the non-indigenous narrow-clawed crayfish Astacus leptodactylus has expanded due to anthropogenic activities. Knowledge about crayfish distribution and early detection of non-indigenous and invasive species are crucial elements in successful conservation of indigenous crayfish. The use of environmental DNA (eDNA) extracted from water samples is a promising new tool for early and non-invasive detection of species in aquatic environments. In the present study, we have developed and tested quantitative PCR (qPCR) assays for species-specific detection and quantification of the three above mentioned crayfish species on the basis of mitochondrial cytochrome oxidase 1 (mtDNA-CO1), including separate assays for two clades of A. leptodactylus. The limit of detection (LOD) was experimentally established as 5 copies/PCR with two different approaches, and the limit of quantification (LOQ) were determined to 5 and 10 copies/PCR, respectively, depending on chosen approach. The assays detected crayfish in natural freshwater ecosystems with known populations of all three species, and show promising potentials for future monitoring of A. astacus, P. leniusculus and A. leptodactylus. However, the assays need further validation with data 1) comparing traditional and eDNA based estimates of abundance, and 2) representing a broader geographical range for the involved crayfish species. PMID:28654642

The distribution of calcium in toad cardiac pacemaker cells during spontaneous firing.

PubMed

Ju, Y K; Allen, D G

2000-12-01

Isolated, spontaneously active pacemaker cells from the sinus venosus region of the toad heart were loaded with the calcium indicator fluo-3. The cells were examined with a confocal microscope to investigate the distribution of calcium during spontaneous activity. Three classes of calcium-related signals were present. First, intense, localised, time-invariant signals were detected from structures distributed across the cell interior. Based on the insensitivity to saponin and the distribution in the cell, these signals appear to arise from fluo-3 located in the sarcoplasmic reticulum and the nuclear envelope. Second, spatially uniform signals from the cytoplasm were present at rest and showed spontaneous increases in [Ca2+]i which propagated along the cell. These Ca2+ transients were uniform in intensity across the diameter of the cell and we could detect no significant delay in the middle of the cell compared to the edges. However, within the nucleus the Ca2+ transient showed a clear delay compared to the cytoplasm. Third, localised, transient increases in [Ca2+]i (Ca2+ sparks) which did not propagate were also detectable. These could be detected both near the surface membrane and in the interior of the cell and reduced in magnitude and increased in duration in the presence of ryanodine. The frequency of firing of Ca2+ sparks significantly increased in the 200-ms period preceding a spontaneous Ca2+ transient. These results suggest that pacemaker cells contain sarcoplasmic reticulum which is distributed across the cell. The Ca2+ transient is uniform across the cell indicating that near-synchronous release of Ca2+ from the sarcoplasmic reticulum is achieved. Ca2+ sparks occur in pacemaker cells though their role in pacemaker function remains to be elucidated.

The Pharmacokinetics of Enrofloxacin in Adult African Clawed Frogs (Xenopus laevis)

PubMed Central

Howard, Antwain M; Papich, Mark G; Felt, Stephen A; Long, Charles T; McKeon, Gabriel P; Bond, Emmitt S; Torreilles, Stéphanie L; Luong, Richard H; Green, Sherril L

2010-01-01

Pharmacokinetics of enrofloxacin, a fluoroquinolone antibiotic, was determined in adult female Xenopus laevis after single-dose administration (10 mg/kg) by intramuscular or subcutaneous injection. Frogs were evaluated at various time points until 8 h after injection. Plasma was analyzed for antibiotic concentration levels by HPLC. We computed pharmacokinetic parameters by using noncompartmental analysis of the pooled concentrations (naive pooled samples). After intramuscular administration of enrofloxacin, the half-life was 5.32 h, concentration maximum was 10.85 µg/mL, distribution volume was 841.96 mL/kg, and area under the time–concentration curve was 57.59 µg×h/mL; after subcutaneous administration these parameters were 4.08 h, 9.76 µg/mL, 915.85 mL/kg, and 47.42 µg×h/mL, respectively. According to plasma pharmacokinetics, Xenopus seem to metabolize enrofloxacin in a manner similar to mammals: low levels of the enrofloxacin metabolite, ciprofloxacin, were detected in the frogs’ habitat water and plasma. At necropsy, there were no gross or histologic signs of toxicity after single-dose administration; toxicity was not evaluated for repeated dosing. The plasma concentrations reached levels considered effective against common aquatic pathogens and suggest that a single, once-daily dose would be a reasonable regimen to consider when treating sick frogs. The treatment of sick frogs should be based on specific microbiologic identification of the pathogen and on antibiotic susceptibility testing. PMID:21205443

Aspartic cathepsin D endopeptidase contributes to extracellular digestion in clawed lobsters Homarus americanus and Homarus gammarus.

PubMed

Rojo, Liliana; Muhlia-Almazan, Adriana; Saborowski, Reinhard; García-Carreño, Fernando

2010-11-01

Acid digestive proteinases were studied in the gastric fluids of two species of clawed lobster (Homarus americanus and Homarus gammarus). An active protein was identified in both species as aspartic proteinase by specific inhibition with pepstatin A. It was confirmed as cathepsin D by mass mapping, N-terminal, and full-length cDNA sequencing. Both lobster species transcribed two cathepsin D mRNAs: cathepsin D1 and cathepsin D2. Cathepsin D1 mRNA was detected only in the midgut gland, suggesting its function as a digestive enzyme. Cathepsin D2 mRNA was found in the midgut gland, gonads, and muscle. The deduced amino acid sequence of cathepsin D1 and cathepsin D2 possesses two catalytic DTG active-site motifs, the hallmark of aspartic proteinases. The putatively active cathepsin D1 has a molecular mass of 36.4 kDa and a calculated pI of 4.14 and possesses three potential glycosylation sites. The sequences showed highest similarities with cathepsin D from insects but also with another crustacean cathepsin D. Cathepsin D1 transcripts were quantified during a starvation period using real-time qPCR. In H. americanus, 15 days of starvation did not cause significant changes, but subsequent feeding caused a 2.5-fold increase. In H. gammarus, starvation caused a 40% reduction in cathepsin D1 mRNA, and no effect was observed with subsequent feeding.

African Music in the Americas

ERIC Educational Resources Information Center

Goines, Leonard

1977-01-01

Discusses African music, how it survived slavery, why it manifests itself in specific forms, why some of these forms are almost purely African today while others are very European, the specific characteristics of African music that permeate all African-American music, and why African derived religions are flourishing in the black communities of…

Accelerated Gene Evolution and Subfunctionalization in thePseudotetraploid Frog Xenopus Laevis

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

Hellsten, Uffe; Khokha, Mustafa K.; Grammar, Timothy C.

2007-03-01

Ancient whole genome duplications have been implicated in the vertebrate and teleost radiations, and in the emergence of diverse angiosperm lineages, but the evolutionary response to such a perturbation is still poorly understood. The African clawed frog Xenopus laevis experienced a relatively recent tetraploidization {approx} 40 million years ago. Analysis of the considerable amount of EST sequence available for this species together with the genome sequence of the related diploid Xenopus tropicalis provides a unique opportunity to study the genomic response to whole genome duplication.

Obesity and African Americans

MedlinePlus

... Data > Minority Population Profiles > Black/African American > Obesity Obesity and African Americans African American women have the ... youthonline . [Accessed 08/18/2017] HEALTH IMPACT OF OBESITY People who are overweight are more likely to ...

A SNP test to identify Africanized honeybees via proportion of 'African' ancestry.

PubMed

Chapman, Nadine C; Harpur, Brock A; Lim, Julianne; Rinderer, Thomas E; Allsopp, Michael H; Zayed, Amro; Oldroyd, Benjamin P

2015-11-01

The honeybee, Apis mellifera, is the world's most important pollinator and is ubiquitous in most agricultural ecosystems. Four major evolutionary lineages and at least 24 subspecies are recognized. Commercial populations are mainly derived from subspecies originating in Europe (75-95%). The Africanized honeybee is a New World hybrid of A. m. scutellata from Africa and European subspecies, with the African component making up 50-90% of the genome. Africanized honeybees are considered undesirable for bee-keeping in most countries, due to their extreme defensiveness and poor honey production. The international trade in honeybees is restricted, due in part to bans on the importation of queens (and semen) from countries where Africanized honeybees are extant. Some desirable strains from the United States of America that have been bred for traits such as resistance to the mite Varroa destructor are unfortunately excluded from export to countries such as Australia due to the presence of Africanized honeybees in the USA. This study shows that a panel of 95 single nucleotide polymorphisms, chosen to differentiate between the African, Eastern European and Western European lineages, can detect Africanized honeybees with a high degree of confidence via ancestry assignment. Our panel therefore offers a valuable tool to mitigate the risks of spreading Africanized honeybees across the globe and may enable the resumption of queen and bee semen imports from the Americas. © 2015 John Wiley & Sons Ltd.

Monoaminergic integration of diet and social signals in the brains of juvenile spadefoot toads.

PubMed

Burmeister, Sabrina S; Rodriguez Moncalvo, Verónica G; Pfennig, Karin S

2017-09-01

Social behavior often includes the production of species-specific signals (e.g. mating calls or visual displays) that evoke context-dependent behavioral responses from conspecifics. Monoamines are important neuromodulators that have been implicated in context-dependent social behavior, yet we know little about the development of monoaminergic systems and whether they mediate the effects of early life experiences on adult behavior. We examined the effects of diet and social signals on monoamines early in development in the plains spadefoot toad ( Spea bombifrons ), a species in which diet affects the developmental emergence of species recognition and body condition affects the expression of adult mating preferences. To do so, we manipulated the diet of juveniles for 6 weeks following metamorphosis and collected their brains 40 min following the presentation of either a conspecific or a heterospecific call. We measured levels of monoamines and their metabolites using high pressure liquid chromatography from tissue punches of the auditory midbrain (i.e. torus semicircularis), hypothalamus and preoptic area. We found that call type affected dopamine and noradrenaline signaling in the auditory midbrain and that diet affected dopamine and serotonin in the hypothalamus. In the preoptic area, we detected an interaction between diet and call type, indicating that diet modulates how the preoptic area integrates social information. Our results suggest that the responsiveness of monoamine systems varies across the brain and highlight preoptic dopamine and noradrenaline as candidates for mediating effects of early diet experience on later expression of social preferences. © 2017. Published by The Company of Biologists Ltd.